openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity
linux/arch/powerpc/kernel/entry_64.S

1227 lines
30 KiB
ArmAsm
Raw Normal View History

powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
* Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
* Adapted for Power Macintosh by Paul Mackerras.
* Low-level exception handlers and MMU support
* rewritten by Paul Mackerras.
* Copyright (C) 1996 Paul Mackerras.
* MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
*
* This file contains the system call entry code, context switch
* code, and exception/interrupt return code for PowerPC.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/errno.h>
powerpc/kernel: Switch to using MAX_ERRNO Currently on powerpc we have our own #define for the highest (negative) errno value, called _LAST_ERRNO. This is defined to be 516, for reasons which are not clear. The generic code, and x86, use MAX_ERRNO, which is defined to be 4095. In particular seccomp uses MAX_ERRNO to restrict the value that a seccomp filter can return. Currently with the mismatch between _LAST_ERRNO and MAX_ERRNO, a seccomp tracer wanting to return 600, expecting it to be seen as an error, would instead find on powerpc that userspace sees a successful syscall with a return value of 600. To avoid this inconsistency, switch powerpc to use MAX_ERRNO. We are somewhat confident that generic syscalls that can return a non-error value above negative MAX_ERRNO have already been updated to use force_successful_syscall_return(). I have also checked all the powerpc specific syscalls, and believe that none of them expect to return a non-error value between -MAX_ERRNO and -516. So this change should be safe ... Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:01 +08:00
#include <linux/err.h>
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
#include <asm/unistd.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
[POWERPC] implement BEGIN/END_FW_FTR_SECTION and use it an all the obvious places in assembler code. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
2006-09-25 16:19:00 +08:00
#include <asm/firmware.h>
[POWERPC] Fix manual assembly WARN_ON() in enter_rtas(). When we switched over to the generic BUG mechanism we forgot to change the assembly code which open-codes a WARN_ON() in enter_rtas(), so the bug table got corrupted. This patch provides an EMIT_BUG_ENTRY macro for use in assembly code, and uses it in entry_64.S. Tested with CONFIG_DEBUG_BUGVERBOSE on ppc64 but not without -- I tried to turn it off but it wouldn't go away; I suspect Aunt Tillie probably needed it. This version gets __FILE__ and __LINE__ right in the assembly version -- rather than saying include/asm-powerpc/bug.h line 21 every time which is a little suboptimal. Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-01-02 02:45:34 +08:00
#include <asm/bug.h>
[POWERPC] Move stackframe definitions to common header This moves various definitions used all over the place to parse stack frames to ptrace.h so only one definition is needed. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 12:34:59 +08:00
#include <asm/ptrace.h>
[POWERPC] irqtrace support for 64-bit powerpc This adds the low level irq tracing hooks to the powerpc architecture needed to enable full lockdep functionality. This is partly based on Johannes Berg's initial version. I removed the asm trampoline that isn't needed (thus improving performance) and modified all sorts of bits and pieces, reworking most of the assembly, etc... Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 12:35:01 +08:00
#include <asm/irqflags.h>
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
#include <asm/hw_irq.h>
powerpc: Use the new schedule_user API on userspace preemption This patch corresponds to [PATCH] x86: Use the new schedule_user API on userspace preemption commit 0430499ce9d78691f3985962021b16bf8f8a8048 Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-14 00:16:43 +08:00
#include <asm/context_tracking.h>
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
#include <asm/tm.h>
powerpc: Add support for userspace P9 copy paste The copy paste facility introduced in POWER9 provides an optimised mechanism for a userspace application to copy a cacheline. This is provided by a pair of instructions, copy and paste, while a third, cp_abort (copy paste abort), provides a clean up of the state in case of a failure. The copy instruction will read a 128 byte cacheline and store it in an internal buffer. The subsequent paste instruction will store this internal buffer to memory and set a CR field if the paste succeeds. Since the state of the copy paste buffer is internal (and not architecturally visible), in the unlikely event of a context switch, the state cannot be stored and the paste should therefore fail. The cp_abort instruction exists to fail and clean up any such interrupted copy paste sequence and is to be called by the kernel as part of the context switch. Doing so prevents data from a preceding copy in one process leaking into the paste of another. This code enables use of the cp_abort instruction if a supported processor is detected. NOTE: this is for userspace only, not in kernel, and does not deal with KVM guests. Patch created with much assistance from Michael Neuling <mikey@neuling.org> Signed-off-by: Chris Smart <chris@distroguy.com> Reviewed-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-04-26 08:28:50 +08:00
#include <asm/ppc-opcode.h>
ppc: move exports to definitions Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-14 12:33:46 +08:00
#include <asm/export.h>
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/*
* System calls.
*/
.section ".toc","aw"
powerpc: Don't use a function descriptor for system call table There is no need to create a function descriptor for the system call table. By using one we force the system call table into the text section and it really belongs in the rodata section. This also removes another use of dot symbols. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:05:53 +08:00
SYS_CALL_TABLE:
.tc sys_call_table[TC],sys_call_table
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* This value is used to mark exception frames on the stack. */
exception_marker:
[POWERPC] Move stackframe definitions to common header This moves various definitions used all over the place to parse stack frames to ptrace.h so only one definition is needed. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 12:34:59 +08:00
.tc ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
.section ".text"
.align 7
.globl system_call_common
system_call_common:
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
BEGIN_FTR_SECTION
extrdi. r10, r12, 1, (63-MSR_TS_T_LG) /* transaction active? */
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
bne .Ltabort_syscall
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
END_FTR_SECTION_IFSET(CPU_FTR_TM)
#endif
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
andi. r10,r12,MSR_PR
mr r10,r1
addi r1,r1,-INT_FRAME_SIZE
beq- 1f
ld r1,PACAKSAVE(r13)
1: std r10,0(r1)
std r11,_NIP(r1)
std r12,_MSR(r1)
std r0,GPR0(r1)
std r10,GPR1(r1)
powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller [PATCH 1/6] powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller The first instruction in ACCOUNT_CPU_USER_ENTRY is 'beq' which checks for exceptions coming from kernel mode. PPR value will be saved immediately after ACCOUNT_CPU_USER_ENTRY and is also for user level exceptions. So moved this branch instruction in the caller code. Signed-off-by: Haren Myneni <haren@us.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-12-07 05:46:37 +08:00
beq 2f /* if from kernel mode */
powerpc32: provide VIRT_CPU_ACCOUNTING This patch provides VIRT_CPU_ACCOUTING to PPC32 architecture. PPC32 doesn't have the PACA structure, so we use the task_info structure to store the accounting data. In order to reuse on PPC32 the PPC64 functions, all u64 data has been replaced by 'unsigned long' so that it is u32 on PPC32 and u64 on PPC64 Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Scott Wood <oss@buserror.net>
2016-05-17 14:33:46 +08:00
ACCOUNT_CPU_USER_ENTRY(r13, r10, r11)
powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller [PATCH 1/6] powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller The first instruction in ACCOUNT_CPU_USER_ENTRY is 'beq' which checks for exceptions coming from kernel mode. PPR value will be saved immediately after ACCOUNT_CPU_USER_ENTRY and is also for user level exceptions. So moved this branch instruction in the caller code. Signed-off-by: Haren Myneni <haren@us.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-12-07 05:46:37 +08:00
2: std r2,GPR2(r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
std r3,GPR3(r1)
powerpc: Better scheduling of CR save code in system call path At the moment system call entry looks like: crclr so ... mfcr r9 ... std r9,_CCR(r1) commit bd19c8994a82 ([POWERPC] system call micro optimisation) put some space between the crclr and mfcr in order to avoid a stall. There is still a stall seen between the mfcr and std. We can avoid the crclr by doing it in a GPR with rlwinm which gives us more room to better schedule the sequence. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-05 11:44:48 +08:00
mfcr r2
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
std r4,GPR4(r1)
std r5,GPR5(r1)
std r6,GPR6(r1)
std r7,GPR7(r1)
std r8,GPR8(r1)
li r11,0
std r11,GPR9(r1)
std r11,GPR10(r1)
std r11,GPR11(r1)
std r11,GPR12(r1)
powerpc: No need to save XER in a system call The XER is a volatile register so there is no need to save and restore it over a system call - zero it out in the exception stack frame instead. This should fix a 5 cycle stall of the mfxer/std seen on POWER7. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-05 02:24:29 +08:00
std r11,_XER(r1)
powerpc: No need to preserve count register across system call The count register is volatile so we don't need to preserve it. Store zero to the entry in the exception frame. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-05 02:26:39 +08:00
std r11,_CTR(r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
std r9,GPR13(r1)
mflr r10
powerpc: Better scheduling of CR save code in system call path At the moment system call entry looks like: crclr so ... mfcr r9 ... std r9,_CCR(r1) commit bd19c8994a82 ([POWERPC] system call micro optimisation) put some space between the crclr and mfcr in order to avoid a stall. There is still a stall seen between the mfcr and std. We can avoid the crclr by doing it in a GPR with rlwinm which gives us more room to better schedule the sequence. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-05 11:44:48 +08:00
/*
* This clears CR0.SO (bit 28), which is the error indication on
* return from this system call.
*/
rldimi r2,r11,28,(63-28)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
li r11,0xc01
std r10,_LINK(r1)
std r11,_TRAP(r1)
std r3,ORIG_GPR3(r1)
powerpc: Better scheduling of CR save code in system call path At the moment system call entry looks like: crclr so ... mfcr r9 ... std r9,_CCR(r1) commit bd19c8994a82 ([POWERPC] system call micro optimisation) put some space between the crclr and mfcr in order to avoid a stall. There is still a stall seen between the mfcr and std. We can avoid the crclr by doing it in a GPR with rlwinm which gives us more room to better schedule the sequence. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-05 11:44:48 +08:00
std r2,_CCR(r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r2,PACATOC(r13)
addi r9,r1,STACK_FRAME_OVERHEAD
ld r11,exception_marker@toc(r2)
std r11,-16(r9) /* "regshere" marker */
cputime: Generic on-demand virtual cputime accounting If we want to stop the tick further idle, we need to be able to account the cputime without using the tick. Virtual based cputime accounting solves that problem by hooking into kernel/user boundaries. However implementing CONFIG_VIRT_CPU_ACCOUNTING require low level hooks and involves more overhead. But we already have a generic context tracking subsystem that is required for RCU needs by archs which plan to shut down the tick outside idle. This patch implements a generic virtual based cputime accounting that relies on these generic kernel/user hooks. There are some upsides of doing this: - This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING if context tracking is already built (already necessary for RCU in full tickless mode). - We can rely on the generic context tracking subsystem to dynamically (de)activate the hooks, so that we can switch anytime between virtual and tick based accounting. This way we don't have the overhead of the virtual accounting when the tick is running periodically. And one downside: - There is probably more overhead than a native virtual based cputime accounting. But this relies on hooks that are already set anyway. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2012-07-25 13:56:04 +08:00
#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC_SPLPAR)
powerpc: Account time using timebase rather than PURR Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the PURR register for measuring the user and system time used by processes, as well as other related times such as hardirq and softirq times. This turns out to be quite confusing for users because it means that a program will often be measured as taking less time when run on a multi-threaded processor (SMT2 or SMT4 mode) than it does when run on a single-threaded processor (ST mode), even though the program takes longer to finish. The discrepancy is accounted for as stolen time, which is also confusing, particularly when there are no other partitions running. This changes the accounting to use the timebase instead, meaning that the reported user and system times are the actual number of real-time seconds that the program was executing on the processor thread, regardless of which SMT mode the processor is in. Thus a program will generally show greater user and system times when run on a multi-threaded processor than on a single-threaded processor. On pSeries systems on POWER5 or later processors, we measure the stolen time (time when this partition wasn't running) using the hypervisor dispatch trace log. We check for new entries in the log on every entry from user mode and on every transition from kernel process context to soft or hard IRQ context (i.e. when account_system_vtime() gets called). So that we can correctly distinguish time stolen from user time and time stolen from system time, without having to check the log on every exit to user mode, we store separate timestamps for exit to user mode and entry from user mode. On systems that have a SPURR (POWER6 and POWER7), we read the SPURR in account_system_vtime() (as before), and then apportion the SPURR ticks since the last time we read it between scaled user time and scaled system time according to the relative proportions of user time and system time over the same interval. This avoids having to read the SPURR on every kernel entry and exit. On systems that have PURR but not SPURR (i.e., POWER5), we do the same using the PURR rather than the SPURR. This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl for now since it conflicts with the use of the dispatch trace log by the time accounting code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-27 03:56:43 +08:00
BEGIN_FW_FTR_SECTION
beq 33f
/* if from user, see if there are any DTL entries to process */
ld r10,PACALPPACAPTR(r13) /* get ptr to VPA */
ld r11,PACA_DTL_RIDX(r13) /* get log read index */
powerpc: Fix little endian lppaca, slb_shadow and dtl_entry The lppaca, slb_shadow and dtl_entry hypervisor structures are big endian, so we have to byte swap them in little endian builds. LE KVM hosts will also need to be fixed but for now add an #error to remind us. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-08-07 00:01:46 +08:00
addi r10,r10,LPPACA_DTLIDX
LDX_BE r10,0,r10 /* get log write index */
powerpc: Account time using timebase rather than PURR Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the PURR register for measuring the user and system time used by processes, as well as other related times such as hardirq and softirq times. This turns out to be quite confusing for users because it means that a program will often be measured as taking less time when run on a multi-threaded processor (SMT2 or SMT4 mode) than it does when run on a single-threaded processor (ST mode), even though the program takes longer to finish. The discrepancy is accounted for as stolen time, which is also confusing, particularly when there are no other partitions running. This changes the accounting to use the timebase instead, meaning that the reported user and system times are the actual number of real-time seconds that the program was executing on the processor thread, regardless of which SMT mode the processor is in. Thus a program will generally show greater user and system times when run on a multi-threaded processor than on a single-threaded processor. On pSeries systems on POWER5 or later processors, we measure the stolen time (time when this partition wasn't running) using the hypervisor dispatch trace log. We check for new entries in the log on every entry from user mode and on every transition from kernel process context to soft or hard IRQ context (i.e. when account_system_vtime() gets called). So that we can correctly distinguish time stolen from user time and time stolen from system time, without having to check the log on every exit to user mode, we store separate timestamps for exit to user mode and entry from user mode. On systems that have a SPURR (POWER6 and POWER7), we read the SPURR in account_system_vtime() (as before), and then apportion the SPURR ticks since the last time we read it between scaled user time and scaled system time according to the relative proportions of user time and system time over the same interval. This avoids having to read the SPURR on every kernel entry and exit. On systems that have PURR but not SPURR (i.e., POWER5), we do the same using the PURR rather than the SPURR. This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl for now since it conflicts with the use of the dispatch trace log by the time accounting code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-27 03:56:43 +08:00
cmpd cr1,r11,r10
beq+ cr1,33f
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl accumulate_stolen_time
powerpc: Account time using timebase rather than PURR Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the PURR register for measuring the user and system time used by processes, as well as other related times such as hardirq and softirq times. This turns out to be quite confusing for users because it means that a program will often be measured as taking less time when run on a multi-threaded processor (SMT2 or SMT4 mode) than it does when run on a single-threaded processor (ST mode), even though the program takes longer to finish. The discrepancy is accounted for as stolen time, which is also confusing, particularly when there are no other partitions running. This changes the accounting to use the timebase instead, meaning that the reported user and system times are the actual number of real-time seconds that the program was executing on the processor thread, regardless of which SMT mode the processor is in. Thus a program will generally show greater user and system times when run on a multi-threaded processor than on a single-threaded processor. On pSeries systems on POWER5 or later processors, we measure the stolen time (time when this partition wasn't running) using the hypervisor dispatch trace log. We check for new entries in the log on every entry from user mode and on every transition from kernel process context to soft or hard IRQ context (i.e. when account_system_vtime() gets called). So that we can correctly distinguish time stolen from user time and time stolen from system time, without having to check the log on every exit to user mode, we store separate timestamps for exit to user mode and entry from user mode. On systems that have a SPURR (POWER6 and POWER7), we read the SPURR in account_system_vtime() (as before), and then apportion the SPURR ticks since the last time we read it between scaled user time and scaled system time according to the relative proportions of user time and system time over the same interval. This avoids having to read the SPURR on every kernel entry and exit. On systems that have PURR but not SPURR (i.e., POWER5), we do the same using the PURR rather than the SPURR. This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl for now since it conflicts with the use of the dispatch trace log by the time accounting code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-27 03:56:43 +08:00
REST_GPR(0,r1)
REST_4GPRS(3,r1)
REST_2GPRS(7,r1)
addi r9,r1,STACK_FRAME_OVERHEAD
33:
END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
cputime: Generic on-demand virtual cputime accounting If we want to stop the tick further idle, we need to be able to account the cputime without using the tick. Virtual based cputime accounting solves that problem by hooking into kernel/user boundaries. However implementing CONFIG_VIRT_CPU_ACCOUNTING require low level hooks and involves more overhead. But we already have a generic context tracking subsystem that is required for RCU needs by archs which plan to shut down the tick outside idle. This patch implements a generic virtual based cputime accounting that relies on these generic kernel/user hooks. There are some upsides of doing this: - This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING if context tracking is already built (already necessary for RCU in full tickless mode). - We can rely on the generic context tracking subsystem to dynamically (de)activate the hooks, so that we can switch anytime between virtual and tick based accounting. This way we don't have the overhead of the virtual accounting when the tick is running periodically. And one downside: - There is probably more overhead than a native virtual based cputime accounting. But this relies on hooks that are already set anyway. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2012-07-25 13:56:04 +08:00
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE && CONFIG_PPC_SPLPAR */
powerpc: Account time using timebase rather than PURR Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the PURR register for measuring the user and system time used by processes, as well as other related times such as hardirq and softirq times. This turns out to be quite confusing for users because it means that a program will often be measured as taking less time when run on a multi-threaded processor (SMT2 or SMT4 mode) than it does when run on a single-threaded processor (ST mode), even though the program takes longer to finish. The discrepancy is accounted for as stolen time, which is also confusing, particularly when there are no other partitions running. This changes the accounting to use the timebase instead, meaning that the reported user and system times are the actual number of real-time seconds that the program was executing on the processor thread, regardless of which SMT mode the processor is in. Thus a program will generally show greater user and system times when run on a multi-threaded processor than on a single-threaded processor. On pSeries systems on POWER5 or later processors, we measure the stolen time (time when this partition wasn't running) using the hypervisor dispatch trace log. We check for new entries in the log on every entry from user mode and on every transition from kernel process context to soft or hard IRQ context (i.e. when account_system_vtime() gets called). So that we can correctly distinguish time stolen from user time and time stolen from system time, without having to check the log on every exit to user mode, we store separate timestamps for exit to user mode and entry from user mode. On systems that have a SPURR (POWER6 and POWER7), we read the SPURR in account_system_vtime() (as before), and then apportion the SPURR ticks since the last time we read it between scaled user time and scaled system time according to the relative proportions of user time and system time over the same interval. This avoids having to read the SPURR on every kernel entry and exit. On systems that have PURR but not SPURR (i.e., POWER5), we do the same using the PURR rather than the SPURR. This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl for now since it conflicts with the use of the dispatch trace log by the time accounting code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-27 03:56:43 +08:00
powerpc: Improve 64-bit syscall entry/exit We unconditionally hard enable interrupts. This is unnecessary as syscalls are expected to always be called with interrupts enabled. While at it, we add a WARN_ON if that is not the case and CONFIG_TRACE_IRQFLAGS is enabled (we don't want to add overhead to the fast path when this is not set though). Thus let's remove the enabling (and associated irq tracing) from the syscall entry path. Also on Book3S, replace a few mfmsr instructions with loads of PACAMSR from the PACA, which should be faster & schedule better. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-01 12:40:23 +08:00
/*
* A syscall should always be called with interrupts enabled
* so we just unconditionally hard-enable here. When some kind
* of irq tracing is used, we additionally check that condition
* is correct
*/
#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_BUG)
lbz r10,PACASOFTIRQEN(r13)
xori r10,r10,1
1: tdnei r10,0
EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING
#endif
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#ifdef CONFIG_PPC_BOOK3E
wrteei 1
#else
powerpc/64s: Optimise MSR handling in exception handling mtmsrd with L=1 only affects MSR_EE and MSR_RI bits, and we always know what state those bits are, so the kernel MSR does not need to be loaded when modifying them. mtmsrd is often in the critical execution path, so avoiding dependency on even L1 load is noticable. On a POWER8 this saves about 3 cycles from the syscall path, and possibly a few from other exception returns (not measured). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-15 17:04:46 +08:00
li r11,MSR_RI
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ori r11,r11,MSR_EE
mtmsrd r11,1
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#endif /* CONFIG_PPC_BOOK3E */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc/64s: Move system_call() symbol to just after setting MSR_EE It is common to get a PMU interrupt right after the mtmsr instruction that enables interrupts. Due to this, the stack trace profile gets needlessly split across system_call_common() and system_call(). Previously, system_call() symbol was at the current place to hide a few earlier symbols which have since been made private or removed entirely. So, let's move system_call() slightly higher up, right after the mtmsr instruction that enables interrupts. Convert existing references to system_call to a local syscall symbol. Suggested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:17 +08:00
system_call: /* label this so stack traces look sane */
powerpc: Improve 64-bit syscall entry/exit We unconditionally hard enable interrupts. This is unnecessary as syscalls are expected to always be called with interrupts enabled. While at it, we add a WARN_ON if that is not the case and CONFIG_TRACE_IRQFLAGS is enabled (we don't want to add overhead to the fast path when this is not set though). Thus let's remove the enabling (and associated irq tracing) from the syscall entry path. Also on Book3S, replace a few mfmsr instructions with loads of PACAMSR from the PACA, which should be faster & schedule better. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-01 12:40:23 +08:00
/* We do need to set SOFTE in the stack frame or the return
* from interrupt will be painful
*/
li r10,1
std r10,SOFTE(r1)
powerpc: Use CURRENT_THREAD_INFO instead of open coded assembly Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-05 12:41:35 +08:00
CURRENT_THREAD_INFO(r11, r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r10,TI_FLAGS(r11)
powerpc: Rename _TIF_SYSCALL_T_OR_A to _TIF_SYSCALL_DOTRACE Once upon a time, at least 9 years ago (< 2.6.12), _TIF_SYSCALL_T_OR_A meant "TRACE or AUDIT". But these days it means TRACE or AUDIT or SECCOMP or TRACEPOINT or NOHZ. All of those are implemented via syscall_dotrace() so rename the flag to that to try and clarify things. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-01-15 09:01:42 +08:00
andi. r11,r10,_TIF_SYSCALL_DOTRACE
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
bne .Lsyscall_dotrace /* does not return */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
cmpldi 0,r0,NR_syscalls
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
bge- .Lsyscall_enosys
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc/64s: Move system_call() symbol to just after setting MSR_EE It is common to get a PMU interrupt right after the mtmsr instruction that enables interrupts. Due to this, the stack trace profile gets needlessly split across system_call_common() and system_call(). Previously, system_call() symbol was at the current place to hide a few earlier symbols which have since been made private or removed entirely. So, let's move system_call() slightly higher up, right after the mtmsr instruction that enables interrupts. Convert existing references to system_call to a local syscall symbol. Suggested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:17 +08:00
.Lsyscall:
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/*
* Need to vector to 32 Bit or default sys_call_table here,
* based on caller's run-mode / personality.
*/
powerpc: Don't use a function descriptor for system call table There is no need to create a function descriptor for the system call table. By using one we force the system call table into the text section and it really belongs in the rodata section. This also removes another use of dot symbols. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:05:53 +08:00
ld r11,SYS_CALL_TABLE@toc(2)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
andi. r10,r10,_TIF_32BIT
beq 15f
addi r11,r11,8 /* use 32-bit syscall entries */
clrldi r3,r3,32
clrldi r4,r4,32
clrldi r5,r5,32
clrldi r6,r6,32
clrldi r7,r7,32
clrldi r8,r8,32
15:
slwi r0,r0,4
powerpc: ABIv2 function calls must place target address in r12 To establish addressability quickly, ABIv2 requires the target address of the function being called to be in r12. Fix a number of places in assembly code that we do indirect function calls. We need to avoid function descriptors on ABIv2 too. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:47 +08:00
ldx r12,r11,r0 /* Fetch system call handler [ptr] */
mtctr r12
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
bctrl /* Call handler */
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
.Lsyscall_exit:
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
std r3,RESULT(r1)
powerpc: Use CURRENT_THREAD_INFO instead of open coded assembly Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-05 12:41:35 +08:00
CURRENT_THREAD_INFO(r12, r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r8,_MSR(r1)
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#ifdef CONFIG_PPC_BOOK3S
/* No MSR:RI on BookE */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
andi. r10,r8,MSR_RI
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
beq- .Lunrecov_restore
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#endif
powerpc/64s: Un-blacklist system_call() from kprobes It is actually safe to probe system_call() in entry_64.S, but only till we unset MSR_RI. To allow this, add a new symbol system_call_exit() after the mtmsrd and blacklist that. Suggested-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:18 +08:00
/*
* This is a few instructions into the actual syscall exit path (which actually
* starts at .Lsyscall_exit) to cater to kprobe blacklisting and to reduce the
* number of visible symbols for profiling purposes.
*
* We can probe from system_call until this point as MSR_RI is set. But once it
* is cleared below, we won't be able to take a trap.
*
* This is blacklisted from kprobes further below with _ASM_NOKPROBE_SYMBOL().
*/
system_call_exit:
powerpc: Improve 64-bit syscall entry/exit We unconditionally hard enable interrupts. This is unnecessary as syscalls are expected to always be called with interrupts enabled. While at it, we add a WARN_ON if that is not the case and CONFIG_TRACE_IRQFLAGS is enabled (we don't want to add overhead to the fast path when this is not set though). Thus let's remove the enabling (and associated irq tracing) from the syscall entry path. Also on Book3S, replace a few mfmsr instructions with loads of PACAMSR from the PACA, which should be faster & schedule better. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-01 12:40:23 +08:00
/*
* Disable interrupts so current_thread_info()->flags can't change,
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
* and so that we don't get interrupted after loading SRR0/1.
*/
#ifdef CONFIG_PPC_BOOK3E
wrteei 0
#else
powerpc: Clear RI and EE at the same time in system call exit mtmsrd is an expensive instruction, we save a few cycles by doing it once instead of twice. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-29 20:22:00 +08:00
/*
* For performance reasons we clear RI the same time that we
* clear EE. We only need to clear RI just before we restore r13
* below, but batching it with EE saves us one expensive mtmsrd call.
* We have to be careful to restore RI if we branch anywhere from
* here (eg syscall_exit_work).
*/
powerpc/64s: Optimise MSR handling in exception handling mtmsrd with L=1 only affects MSR_EE and MSR_RI bits, and we always know what state those bits are, so the kernel MSR does not need to be loaded when modifying them. mtmsrd is often in the critical execution path, so avoiding dependency on even L1 load is noticable. On a POWER8 this saves about 3 cycles from the syscall path, and possibly a few from other exception returns (not measured). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-15 17:04:46 +08:00
li r11,0
powerpc: Clear RI and EE at the same time in system call exit mtmsrd is an expensive instruction, we save a few cycles by doing it once instead of twice. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-29 20:22:00 +08:00
mtmsrd r11,1
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#endif /* CONFIG_PPC_BOOK3E */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r9,TI_FLAGS(r12)
powerpc/kernel: Switch to using MAX_ERRNO Currently on powerpc we have our own #define for the highest (negative) errno value, called _LAST_ERRNO. This is defined to be 516, for reasons which are not clear. The generic code, and x86, use MAX_ERRNO, which is defined to be 4095. In particular seccomp uses MAX_ERRNO to restrict the value that a seccomp filter can return. Currently with the mismatch between _LAST_ERRNO and MAX_ERRNO, a seccomp tracer wanting to return 600, expecting it to be seen as an error, would instead find on powerpc that userspace sees a successful syscall with a return value of 600. To avoid this inconsistency, switch powerpc to use MAX_ERRNO. We are somewhat confident that generic syscalls that can return a non-error value above negative MAX_ERRNO have already been updated to use force_successful_syscall_return(). I have also checked all the powerpc specific syscalls, and believe that none of them expect to return a non-error value between -MAX_ERRNO and -516. So this change should be safe ... Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:01 +08:00
li r11,-MAX_ERRNO
powerpc: Rename _TIF_SYSCALL_T_OR_A to _TIF_SYSCALL_DOTRACE Once upon a time, at least 9 years ago (< 2.6.12), _TIF_SYSCALL_T_OR_A meant "TRACE or AUDIT". But these days it means TRACE or AUDIT or SECCOMP or TRACEPOINT or NOHZ. All of those are implemented via syscall_dotrace() so rename the flag to that to try and clarify things. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-01-15 09:01:42 +08:00
andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
bne- .Lsyscall_exit_work
powerpc: Restore FPU/VEC/VSX if previously used Currently the FPU, VEC and VSX facilities are lazily loaded. This is not a problem unless a process is using these facilities. Modern versions of GCC are very good at automatically vectorising code, new and modernised workloads make use of floating point and vector facilities, even the kernel makes use of vectorised memcpy. All this combined greatly increases the cost of a syscall since the kernel uses the facilities sometimes even in syscall fast-path making it increasingly common for a thread to take an *_unavailable exception soon after a syscall, not to mention potentially taking all three. The obvious overcompensation to this problem is to simply always load all the facilities on every exit to userspace. Loading up all FPU, VEC and VSX registers every time can be expensive and if a workload does avoid using them, it should not be forced to incur this penalty. An 8bit counter is used to detect if the registers have been used in the past and the registers are always loaded until the value wraps to back to zero. Several versions of the assembly in entry_64.S were tested: 1. Always calling C. 2. Performing a common case check and then calling C. 3. A complex check in asm. After some benchmarking it was determined that avoiding C in the common case is a performance benefit (option 2). The full check in asm (option 3) greatly complicated that codepath for a negligible performance gain and the trade-off was deemed not worth it. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> [mpe: Move load_vec in the struct to fill an existing hole, reword change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> fixup
2016-02-29 14:53:47 +08:00
powerpc/64: Avoid restore_math call if possible in syscall exit The syscall exit code that branches to restore_math is quite heavy on Book3S, consisting of 2 mtmsr instructions. Threads that don't use both FP and vector can get caught here if the kernel ever uses FP or vector. Lazy-FP/vec context switching also trips this case. So check for lazy FP and vector before switching RI for restore_math. Move most of this case out of line. For threads that do want to restore math registers, the MSR switches are still suboptimal. Future direction may be to use a soft-RI bit to avoid MSR switches in kernel (similar to soft-EE), but for now at least the no-restore POWER9 context switch rate increases by about 5% due to sched_yield(2) return performance. I haven't constructed a test to measure the syscall cost. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:35:05 +08:00
/* If MSR_FP and MSR_VEC are set in user msr, then no need to restore */
li r7,MSR_FP
powerpc: Restore FPU/VEC/VSX if previously used Currently the FPU, VEC and VSX facilities are lazily loaded. This is not a problem unless a process is using these facilities. Modern versions of GCC are very good at automatically vectorising code, new and modernised workloads make use of floating point and vector facilities, even the kernel makes use of vectorised memcpy. All this combined greatly increases the cost of a syscall since the kernel uses the facilities sometimes even in syscall fast-path making it increasingly common for a thread to take an *_unavailable exception soon after a syscall, not to mention potentially taking all three. The obvious overcompensation to this problem is to simply always load all the facilities on every exit to userspace. Loading up all FPU, VEC and VSX registers every time can be expensive and if a workload does avoid using them, it should not be forced to incur this penalty. An 8bit counter is used to detect if the registers have been used in the past and the registers are always loaded until the value wraps to back to zero. Several versions of the assembly in entry_64.S were tested: 1. Always calling C. 2. Performing a common case check and then calling C. 3. A complex check in asm. After some benchmarking it was determined that avoiding C in the common case is a performance benefit (option 2). The full check in asm (option 3) greatly complicated that codepath for a negligible performance gain and the trade-off was deemed not worth it. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> [mpe: Move load_vec in the struct to fill an existing hole, reword change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> fixup
2016-02-29 14:53:47 +08:00
#ifdef CONFIG_ALTIVEC
powerpc/64: Avoid restore_math call if possible in syscall exit The syscall exit code that branches to restore_math is quite heavy on Book3S, consisting of 2 mtmsr instructions. Threads that don't use both FP and vector can get caught here if the kernel ever uses FP or vector. Lazy-FP/vec context switching also trips this case. So check for lazy FP and vector before switching RI for restore_math. Move most of this case out of line. For threads that do want to restore math registers, the MSR switches are still suboptimal. Future direction may be to use a soft-RI bit to avoid MSR switches in kernel (similar to soft-EE), but for now at least the no-restore POWER9 context switch rate increases by about 5% due to sched_yield(2) return performance. I haven't constructed a test to measure the syscall cost. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:35:05 +08:00
oris r7,r7,MSR_VEC@h
powerpc: Restore FPU/VEC/VSX if previously used Currently the FPU, VEC and VSX facilities are lazily loaded. This is not a problem unless a process is using these facilities. Modern versions of GCC are very good at automatically vectorising code, new and modernised workloads make use of floating point and vector facilities, even the kernel makes use of vectorised memcpy. All this combined greatly increases the cost of a syscall since the kernel uses the facilities sometimes even in syscall fast-path making it increasingly common for a thread to take an *_unavailable exception soon after a syscall, not to mention potentially taking all three. The obvious overcompensation to this problem is to simply always load all the facilities on every exit to userspace. Loading up all FPU, VEC and VSX registers every time can be expensive and if a workload does avoid using them, it should not be forced to incur this penalty. An 8bit counter is used to detect if the registers have been used in the past and the registers are always loaded until the value wraps to back to zero. Several versions of the assembly in entry_64.S were tested: 1. Always calling C. 2. Performing a common case check and then calling C. 3. A complex check in asm. After some benchmarking it was determined that avoiding C in the common case is a performance benefit (option 2). The full check in asm (option 3) greatly complicated that codepath for a negligible performance gain and the trade-off was deemed not worth it. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> [mpe: Move load_vec in the struct to fill an existing hole, reword change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> fixup
2016-02-29 14:53:47 +08:00
#endif
powerpc/64: Avoid restore_math call if possible in syscall exit The syscall exit code that branches to restore_math is quite heavy on Book3S, consisting of 2 mtmsr instructions. Threads that don't use both FP and vector can get caught here if the kernel ever uses FP or vector. Lazy-FP/vec context switching also trips this case. So check for lazy FP and vector before switching RI for restore_math. Move most of this case out of line. For threads that do want to restore math registers, the MSR switches are still suboptimal. Future direction may be to use a soft-RI bit to avoid MSR switches in kernel (similar to soft-EE), but for now at least the no-restore POWER9 context switch rate increases by about 5% due to sched_yield(2) return performance. I haven't constructed a test to measure the syscall cost. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:35:05 +08:00
and r0,r8,r7
cmpd r0,r7
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
bne .Lsyscall_restore_math
powerpc/64: Avoid restore_math call if possible in syscall exit The syscall exit code that branches to restore_math is quite heavy on Book3S, consisting of 2 mtmsr instructions. Threads that don't use both FP and vector can get caught here if the kernel ever uses FP or vector. Lazy-FP/vec context switching also trips this case. So check for lazy FP and vector before switching RI for restore_math. Move most of this case out of line. For threads that do want to restore math registers, the MSR switches are still suboptimal. Future direction may be to use a soft-RI bit to avoid MSR switches in kernel (similar to soft-EE), but for now at least the no-restore POWER9 context switch rate increases by about 5% due to sched_yield(2) return performance. I haven't constructed a test to measure the syscall cost. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:35:05 +08:00
.Lsyscall_restore_math_cont:
powerpc: Restore FPU/VEC/VSX if previously used Currently the FPU, VEC and VSX facilities are lazily loaded. This is not a problem unless a process is using these facilities. Modern versions of GCC are very good at automatically vectorising code, new and modernised workloads make use of floating point and vector facilities, even the kernel makes use of vectorised memcpy. All this combined greatly increases the cost of a syscall since the kernel uses the facilities sometimes even in syscall fast-path making it increasingly common for a thread to take an *_unavailable exception soon after a syscall, not to mention potentially taking all three. The obvious overcompensation to this problem is to simply always load all the facilities on every exit to userspace. Loading up all FPU, VEC and VSX registers every time can be expensive and if a workload does avoid using them, it should not be forced to incur this penalty. An 8bit counter is used to detect if the registers have been used in the past and the registers are always loaded until the value wraps to back to zero. Several versions of the assembly in entry_64.S were tested: 1. Always calling C. 2. Performing a common case check and then calling C. 3. A complex check in asm. After some benchmarking it was determined that avoiding C in the common case is a performance benefit (option 2). The full check in asm (option 3) greatly complicated that codepath for a negligible performance gain and the trade-off was deemed not worth it. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> [mpe: Move load_vec in the struct to fill an existing hole, reword change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> fixup
2016-02-29 14:53:47 +08:00
powerpc/64: Avoid restore_math call if possible in syscall exit The syscall exit code that branches to restore_math is quite heavy on Book3S, consisting of 2 mtmsr instructions. Threads that don't use both FP and vector can get caught here if the kernel ever uses FP or vector. Lazy-FP/vec context switching also trips this case. So check for lazy FP and vector before switching RI for restore_math. Move most of this case out of line. For threads that do want to restore math registers, the MSR switches are still suboptimal. Future direction may be to use a soft-RI bit to avoid MSR switches in kernel (similar to soft-EE), but for now at least the no-restore POWER9 context switch rate increases by about 5% due to sched_yield(2) return performance. I haven't constructed a test to measure the syscall cost. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:35:05 +08:00
cmpld r3,r11
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
ld r5,_CCR(r1)
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
bge- .Lsyscall_error
powerpc: Hide some system call labels from profile tools syscall_dotrace_cont and syscall_error_cont tend to complicate perf output so make them local. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-05 02:23:27 +08:00
.Lsyscall_error_cont:
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r7,_NIP(r1)
powerpc: Feature nop out reservation clear when stcx checks address The POWER architecture does not require stcx to check that it is operating on the same address as the larx. This means it is possible for an an exception handler to execute a larx, get a reservation, decide not to do the stcx and then return back with an active reservation. If the interrupted code was in the middle of a larx/stcx sequence the stcx could incorrectly succeed. All recent POWER CPUs check the address before letting the stcx succeed so we can create a CPU feature and nop it out. As Ben suggested, we can only do this in our syscall path because there is a remote possibility some kernel code gets interrupted by an exception that ends up operating on the same cacheline. Thanks to Paul Mackerras and Derek Williams for the idea. To test this I used a very simple null syscall (actually getppid) testcase at http://ozlabs.org/~anton/junkcode/null_syscall.c I tested against 2.6.35-git10 with the following changes against the pseries_defconfig: CONFIG_VIRT_CPU_ACCOUNTING=n CONFIG_AUDIT=n CONFIG_PPC_4K_PAGES=n CONFIG_PPC_64K_PAGES=y CONFIG_FORCE_MAX_ZONEORDER=9 CONFIG_PPC_SUBPAGE_PROT=n CONFIG_FUNCTION_TRACER=n CONFIG_FUNCTION_GRAPH_TRACER=n CONFIG_IRQSOFF_TRACER=n CONFIG_STACK_TRACER=n to remove the overhead of virtual CPU accounting, syscall auditing and the ftrace mcount tracers. 64kB pages were enabled to minimise TLB misses. POWER6: +8.2% POWER7: +7.0% Another suggestion was to use a larx to something in the L1 instead of a stcx. This was almost as fast as removing the larx on POWER6, but only 3.5% faster on POWER7. We can use this to speed up the reservation clear in our exception exit code. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-11 09:40:27 +08:00
BEGIN_FTR_SECTION
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
stdcx. r0,0,r1 /* to clear the reservation */
powerpc: Feature nop out reservation clear when stcx checks address The POWER architecture does not require stcx to check that it is operating on the same address as the larx. This means it is possible for an an exception handler to execute a larx, get a reservation, decide not to do the stcx and then return back with an active reservation. If the interrupted code was in the middle of a larx/stcx sequence the stcx could incorrectly succeed. All recent POWER CPUs check the address before letting the stcx succeed so we can create a CPU feature and nop it out. As Ben suggested, we can only do this in our syscall path because there is a remote possibility some kernel code gets interrupted by an exception that ends up operating on the same cacheline. Thanks to Paul Mackerras and Derek Williams for the idea. To test this I used a very simple null syscall (actually getppid) testcase at http://ozlabs.org/~anton/junkcode/null_syscall.c I tested against 2.6.35-git10 with the following changes against the pseries_defconfig: CONFIG_VIRT_CPU_ACCOUNTING=n CONFIG_AUDIT=n CONFIG_PPC_4K_PAGES=n CONFIG_PPC_64K_PAGES=y CONFIG_FORCE_MAX_ZONEORDER=9 CONFIG_PPC_SUBPAGE_PROT=n CONFIG_FUNCTION_TRACER=n CONFIG_FUNCTION_GRAPH_TRACER=n CONFIG_IRQSOFF_TRACER=n CONFIG_STACK_TRACER=n to remove the overhead of virtual CPU accounting, syscall auditing and the ftrace mcount tracers. 64kB pages were enabled to minimise TLB misses. POWER6: +8.2% POWER7: +7.0% Another suggestion was to use a larx to something in the L1 instead of a stcx. This was almost as fast as removing the larx on POWER6, but only 3.5% faster on POWER7. We can use this to speed up the reservation clear in our exception exit code. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-11 09:40:27 +08:00
END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
andi. r6,r8,MSR_PR
ld r4,_LINK(r1)
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
powerpc: Implement accurate task and CPU time accounting This implements accurate task and cpu time accounting for 64-bit powerpc kernels. Instead of accounting a whole jiffy of time to a task on a timer interrupt because that task happened to be running at the time, we now account time in units of timebase ticks according to the actual time spent by the task in user mode and kernel mode. We also count the time spent processing hardware and software interrupts accurately. This is conditional on CONFIG_VIRT_CPU_ACCOUNTING. If that is not set, we do tick-based approximate accounting as before. To get this accurate information, we read either the PURR (processor utilization of resources register) on POWER5 machines, or the timebase on other machines on * each entry to the kernel from usermode * each exit to usermode * transitions between process context, hard irq context and soft irq context in kernel mode * context switches. On POWER5 systems with shared-processor logical partitioning we also read both the PURR and the timebase at each timer interrupt and context switch in order to determine how much time has been taken by the hypervisor to run other partitions ("steal" time). Unfortunately, since we need values of the PURR on both threads at the same time to accurately calculate the steal time, and since we can only calculate steal time on a per-core basis, the apportioning of the steal time between idle time (time which we ceded to the hypervisor in the idle loop) and actual stolen time is somewhat approximate at the moment. This is all based quite heavily on what s390 does, and it uses the generic interfaces that were added by the s390 developers, i.e. account_system_time(), account_user_time(), etc. This patch doesn't add any new interfaces between the kernel and userspace, and doesn't change the units in which time is reported to userspace by things such as /proc/stat, /proc/<pid>/stat, getrusage(), times(), etc. Internally the various task and cpu times are stored in timebase units, but they are converted to USER_HZ units (1/100th of a second) when reported to userspace. Some precision is therefore lost but there should not be any accumulating error, since the internal accumulation is at full precision. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-02-24 07:06:59 +08:00
beq- 1f
powerpc32: provide VIRT_CPU_ACCOUNTING This patch provides VIRT_CPU_ACCOUTING to PPC32 architecture. PPC32 doesn't have the PACA structure, so we use the task_info structure to store the accounting data. In order to reuse on PPC32 the PPC64 functions, all u64 data has been replaced by 'unsigned long' so that it is u32 on PPC32 and u64 on PPC64 Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Scott Wood <oss@buserror.net>
2016-05-17 14:33:46 +08:00
ACCOUNT_CPU_USER_EXIT(r13, r11, r12)
powerpc/kernel: Open code HMT_MEDIUM_LOW_HAS_PPR HMT_MEDIUM_LOW_HAS_PPR is only used in once place, open code it. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-11-25 11:25:17 +08:00
BEGIN_FTR_SECTION
HMT_MEDIUM_LOW
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
powerpc: Implement accurate task and CPU time accounting This implements accurate task and cpu time accounting for 64-bit powerpc kernels. Instead of accounting a whole jiffy of time to a task on a timer interrupt because that task happened to be running at the time, we now account time in units of timebase ticks according to the actual time spent by the task in user mode and kernel mode. We also count the time spent processing hardware and software interrupts accurately. This is conditional on CONFIG_VIRT_CPU_ACCOUNTING. If that is not set, we do tick-based approximate accounting as before. To get this accurate information, we read either the PURR (processor utilization of resources register) on POWER5 machines, or the timebase on other machines on * each entry to the kernel from usermode * each exit to usermode * transitions between process context, hard irq context and soft irq context in kernel mode * context switches. On POWER5 systems with shared-processor logical partitioning we also read both the PURR and the timebase at each timer interrupt and context switch in order to determine how much time has been taken by the hypervisor to run other partitions ("steal" time). Unfortunately, since we need values of the PURR on both threads at the same time to accurately calculate the steal time, and since we can only calculate steal time on a per-core basis, the apportioning of the steal time between idle time (time which we ceded to the hypervisor in the idle loop) and actual stolen time is somewhat approximate at the moment. This is all based quite heavily on what s390 does, and it uses the generic interfaces that were added by the s390 developers, i.e. account_system_time(), account_user_time(), etc. This patch doesn't add any new interfaces between the kernel and userspace, and doesn't change the units in which time is reported to userspace by things such as /proc/stat, /proc/<pid>/stat, getrusage(), times(), etc. Internally the various task and cpu times are stored in timebase units, but they are converted to USER_HZ units (1/100th of a second) when reported to userspace. Some precision is therefore lost but there should not be any accumulating error, since the internal accumulation is at full precision. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-02-24 07:06:59 +08:00
ld r13,GPR13(r1) /* only restore r13 if returning to usermode */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
1: ld r2,GPR2(r1)
ld r1,GPR1(r1)
mtlr r4
mtcr r5
mtspr SPRN_SRR0,r7
mtspr SPRN_SRR1,r8
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
RFI
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
b . /* prevent speculative execution */
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
.Lsyscall_error:
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
oris r5,r5,0x1000 /* Set SO bit in CR */
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
neg r3,r3
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
std r5,_CCR(r1)
powerpc: Hide some system call labels from profile tools syscall_dotrace_cont and syscall_error_cont tend to complicate perf output so make them local. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-05 02:23:27 +08:00
b .Lsyscall_error_cont
powerpc/64: Avoid restore_math call if possible in syscall exit The syscall exit code that branches to restore_math is quite heavy on Book3S, consisting of 2 mtmsr instructions. Threads that don't use both FP and vector can get caught here if the kernel ever uses FP or vector. Lazy-FP/vec context switching also trips this case. So check for lazy FP and vector before switching RI for restore_math. Move most of this case out of line. For threads that do want to restore math registers, the MSR switches are still suboptimal. Future direction may be to use a soft-RI bit to avoid MSR switches in kernel (similar to soft-EE), but for now at least the no-restore POWER9 context switch rate increases by about 5% due to sched_yield(2) return performance. I haven't constructed a test to measure the syscall cost. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:35:05 +08:00
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
.Lsyscall_restore_math:
powerpc/64: Avoid restore_math call if possible in syscall exit The syscall exit code that branches to restore_math is quite heavy on Book3S, consisting of 2 mtmsr instructions. Threads that don't use both FP and vector can get caught here if the kernel ever uses FP or vector. Lazy-FP/vec context switching also trips this case. So check for lazy FP and vector before switching RI for restore_math. Move most of this case out of line. For threads that do want to restore math registers, the MSR switches are still suboptimal. Future direction may be to use a soft-RI bit to avoid MSR switches in kernel (similar to soft-EE), but for now at least the no-restore POWER9 context switch rate increases by about 5% due to sched_yield(2) return performance. I haven't constructed a test to measure the syscall cost. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:35:05 +08:00
/*
* Some initial tests from restore_math to avoid the heavyweight
* C code entry and MSR manipulations.
*/
LOAD_REG_IMMEDIATE(r0, MSR_TS_MASK)
and. r0,r0,r8
bne 1f
ld r7,PACACURRENT(r13)
lbz r0,THREAD+THREAD_LOAD_FP(r7)
#ifdef CONFIG_ALTIVEC
lbz r6,THREAD+THREAD_LOAD_VEC(r7)
add r0,r0,r6
#endif
cmpdi r0,0
beq .Lsyscall_restore_math_cont
1: addi r3,r1,STACK_FRAME_OVERHEAD
#ifdef CONFIG_PPC_BOOK3S
li r10,MSR_RI
mtmsrd r10,1 /* Restore RI */
#endif
bl restore_math
#ifdef CONFIG_PPC_BOOK3S
li r11,0
mtmsrd r11,1
#endif
/* Restore volatiles, reload MSR from updated one */
ld r8,_MSR(r1)
ld r3,RESULT(r1)
li r11,-MAX_ERRNO
b .Lsyscall_restore_math_cont
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* Traced system call support */
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
.Lsyscall_dotrace:
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl save_nvgprs
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
addi r3,r1,STACK_FRAME_OVERHEAD
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl do_syscall_trace_enter
powerpc/kernel: Change the do_syscall_trace_enter() API The API for calling do_syscall_trace_enter() is currently sensible enough, it just returns the (modified) syscall number. However once we enable seccomp filter it will get more complicated. When seccomp filter runs, the seccomp kernel code (via SECCOMP_RET_ERRNO), or a ptracer (via SECCOMP_RET_TRACE), may reject the syscall and *may* or may *not* set a return value in r3. That means the assembler that calls do_syscall_trace_enter() can not blindly return ENOSYS, it needs to only return ENOSYS if a return value has not already been set. There is no way to implement that logic with the current API. So change the do_syscall_trace_enter() API to make it deal with the return code juggling, and the assembler can then just return whatever return code it is given. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:02 +08:00
powerpc: Make syscall tracing use tracehook.h helpers This changes powerpc syscall tracing to use the new tracehook.h entry points. There is no change, only cleanup. In addition, the assembly changes allow do_syscall_trace_enter() to abort the syscall without losing the information about the original r0 value. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-07-27 14:51:03 +08:00
/*
powerpc/kernel: Change the do_syscall_trace_enter() API The API for calling do_syscall_trace_enter() is currently sensible enough, it just returns the (modified) syscall number. However once we enable seccomp filter it will get more complicated. When seccomp filter runs, the seccomp kernel code (via SECCOMP_RET_ERRNO), or a ptracer (via SECCOMP_RET_TRACE), may reject the syscall and *may* or may *not* set a return value in r3. That means the assembler that calls do_syscall_trace_enter() can not blindly return ENOSYS, it needs to only return ENOSYS if a return value has not already been set. There is no way to implement that logic with the current API. So change the do_syscall_trace_enter() API to make it deal with the return code juggling, and the assembler can then just return whatever return code it is given. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:02 +08:00
* We use the return value of do_syscall_trace_enter() as the syscall
* number. If the syscall was rejected for any reason do_syscall_trace_enter()
* returns an invalid syscall number and the test below against
* NR_syscalls will fail.
powerpc: Make syscall tracing use tracehook.h helpers This changes powerpc syscall tracing to use the new tracehook.h entry points. There is no change, only cleanup. In addition, the assembly changes allow do_syscall_trace_enter() to abort the syscall without losing the information about the original r0 value. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-07-27 14:51:03 +08:00
*/
mr r0,r3
powerpc/kernel: Change the do_syscall_trace_enter() API The API for calling do_syscall_trace_enter() is currently sensible enough, it just returns the (modified) syscall number. However once we enable seccomp filter it will get more complicated. When seccomp filter runs, the seccomp kernel code (via SECCOMP_RET_ERRNO), or a ptracer (via SECCOMP_RET_TRACE), may reject the syscall and *may* or may *not* set a return value in r3. That means the assembler that calls do_syscall_trace_enter() can not blindly return ENOSYS, it needs to only return ENOSYS if a return value has not already been set. There is no way to implement that logic with the current API. So change the do_syscall_trace_enter() API to make it deal with the return code juggling, and the assembler can then just return whatever return code it is given. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:02 +08:00
/* Restore argument registers just clobbered and/or possibly changed. */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r3,GPR3(r1)
ld r4,GPR4(r1)
ld r5,GPR5(r1)
ld r6,GPR6(r1)
ld r7,GPR7(r1)
ld r8,GPR8(r1)
powerpc/kernel: Change the do_syscall_trace_enter() API The API for calling do_syscall_trace_enter() is currently sensible enough, it just returns the (modified) syscall number. However once we enable seccomp filter it will get more complicated. When seccomp filter runs, the seccomp kernel code (via SECCOMP_RET_ERRNO), or a ptracer (via SECCOMP_RET_TRACE), may reject the syscall and *may* or may *not* set a return value in r3. That means the assembler that calls do_syscall_trace_enter() can not blindly return ENOSYS, it needs to only return ENOSYS if a return value has not already been set. There is no way to implement that logic with the current API. So change the do_syscall_trace_enter() API to make it deal with the return code juggling, and the assembler can then just return whatever return code it is given. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:02 +08:00
powerpc/64s: Move system_call() symbol to just after setting MSR_EE It is common to get a PMU interrupt right after the mtmsr instruction that enables interrupts. Due to this, the stack trace profile gets needlessly split across system_call_common() and system_call(). Previously, system_call() symbol was at the current place to hide a few earlier symbols which have since been made private or removed entirely. So, let's move system_call() slightly higher up, right after the mtmsr instruction that enables interrupts. Convert existing references to system_call to a local syscall symbol. Suggested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:17 +08:00
/* Repopulate r9 and r10 for the syscall path */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
addi r9,r1,STACK_FRAME_OVERHEAD
powerpc: Use CURRENT_THREAD_INFO instead of open coded assembly Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-05 12:41:35 +08:00
CURRENT_THREAD_INFO(r10, r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r10,TI_FLAGS(r10)
powerpc/kernel: Change the do_syscall_trace_enter() API The API for calling do_syscall_trace_enter() is currently sensible enough, it just returns the (modified) syscall number. However once we enable seccomp filter it will get more complicated. When seccomp filter runs, the seccomp kernel code (via SECCOMP_RET_ERRNO), or a ptracer (via SECCOMP_RET_TRACE), may reject the syscall and *may* or may *not* set a return value in r3. That means the assembler that calls do_syscall_trace_enter() can not blindly return ENOSYS, it needs to only return ENOSYS if a return value has not already been set. There is no way to implement that logic with the current API. So change the do_syscall_trace_enter() API to make it deal with the return code juggling, and the assembler can then just return whatever return code it is given. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:02 +08:00
cmpldi r0,NR_syscalls
powerpc/64s: Move system_call() symbol to just after setting MSR_EE It is common to get a PMU interrupt right after the mtmsr instruction that enables interrupts. Due to this, the stack trace profile gets needlessly split across system_call_common() and system_call(). Previously, system_call() symbol was at the current place to hide a few earlier symbols which have since been made private or removed entirely. So, let's move system_call() slightly higher up, right after the mtmsr instruction that enables interrupts. Convert existing references to system_call to a local syscall symbol. Suggested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:17 +08:00
blt+ .Lsyscall
powerpc/kernel: Change the do_syscall_trace_enter() API The API for calling do_syscall_trace_enter() is currently sensible enough, it just returns the (modified) syscall number. However once we enable seccomp filter it will get more complicated. When seccomp filter runs, the seccomp kernel code (via SECCOMP_RET_ERRNO), or a ptracer (via SECCOMP_RET_TRACE), may reject the syscall and *may* or may *not* set a return value in r3. That means the assembler that calls do_syscall_trace_enter() can not blindly return ENOSYS, it needs to only return ENOSYS if a return value has not already been set. There is no way to implement that logic with the current API. So change the do_syscall_trace_enter() API to make it deal with the return code juggling, and the assembler can then just return whatever return code it is given. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:02 +08:00
/* Return code is already in r3 thanks to do_syscall_trace_enter() */
b .Lsyscall_exit
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
.Lsyscall_enosys:
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
li r3,-ENOSYS
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
b .Lsyscall_exit
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
.Lsyscall_exit_work:
powerpc: Clear RI and EE at the same time in system call exit mtmsrd is an expensive instruction, we save a few cycles by doing it once instead of twice. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-29 20:22:00 +08:00
#ifdef CONFIG_PPC_BOOK3S
powerpc/64s: Optimise MSR handling in exception handling mtmsrd with L=1 only affects MSR_EE and MSR_RI bits, and we always know what state those bits are, so the kernel MSR does not need to be loaded when modifying them. mtmsrd is often in the critical execution path, so avoiding dependency on even L1 load is noticable. On a POWER8 this saves about 3 cycles from the syscall path, and possibly a few from other exception returns (not measured). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-15 17:04:46 +08:00
li r10,MSR_RI
powerpc: Clear RI and EE at the same time in system call exit mtmsrd is an expensive instruction, we save a few cycles by doing it once instead of twice. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-29 20:22:00 +08:00
mtmsrd r10,1 /* Restore RI */
#endif
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
/* If TIF_RESTOREALL is set, don't scribble on either r3 or ccr.
If TIF_NOERROR is set, just save r3 as it is. */
andi. r0,r9,_TIF_RESTOREALL
powerpc: Fix various syscall/signal/swapcontext bugs A careful reading of the recent changes to the system call entry/exit paths revealed several problems, plus some things that could be simplified and improved: * 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit path, so it was only doing anything with it once it saw some other bit being set. In other words, the noerror behaviour would apply to the next system call where we had to reschedule or deliver a signal, which is not necessarily the current system call. * 32-bit wasn't doing the call to ptrace_notify in the syscall exit path when the _TIF_SINGLESTEP bit was set. * _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and _TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set by system calls. I took it out of _TIF_USER_WORK_MASK. * On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers to be restored (unless perhaps a signal was delivered or the syscall was traced or single-stepped). Thus the non-volatile registers weren't restored on exit from a signal handler. We probably got away with it mostly because signal handlers written in C wouldn't alter the non-volatile registers. * On 32-bit I simplified the code and made it more like 64-bit by making the syscall exit path jump to ret_from_except to handle preemption and signal delivery. * 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was set - but I think because of that 32-bit was actually restoring the non-volatile registers on exit from a signal handler. * I changed the order of enabling interrupts and saving the non-volatile registers before calling do_syscall_trace_leave; now we enable interrupts first. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-08 10:24:22 +08:00
beq+ 0f
REST_NVGPRS(r1)
b 2f
powerpc/kernel: Switch to using MAX_ERRNO Currently on powerpc we have our own #define for the highest (negative) errno value, called _LAST_ERRNO. This is defined to be 516, for reasons which are not clear. The generic code, and x86, use MAX_ERRNO, which is defined to be 4095. In particular seccomp uses MAX_ERRNO to restrict the value that a seccomp filter can return. Currently with the mismatch between _LAST_ERRNO and MAX_ERRNO, a seccomp tracer wanting to return 600, expecting it to be seen as an error, would instead find on powerpc that userspace sees a successful syscall with a return value of 600. To avoid this inconsistency, switch powerpc to use MAX_ERRNO. We are somewhat confident that generic syscalls that can return a non-error value above negative MAX_ERRNO have already been updated to use force_successful_syscall_return(). I have also checked all the powerpc specific syscalls, and believe that none of them expect to return a non-error value between -MAX_ERRNO and -516. So this change should be safe ... Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Kees Cook <keescook@chromium.org>
2015-07-23 18:21:01 +08:00
0: cmpld r3,r11 /* r11 is -MAX_ERRNO */
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
blt+ 1f
andi. r0,r9,_TIF_NOERROR
bne- 1f
ld r5,_CCR(r1)
neg r3,r3
oris r5,r5,0x1000 /* Set SO bit in CR */
std r5,_CCR(r1)
1: std r3,GPR3(r1)
2: andi. r0,r9,(_TIF_PERSYSCALL_MASK)
beq 4f
powerpc: Fix various syscall/signal/swapcontext bugs A careful reading of the recent changes to the system call entry/exit paths revealed several problems, plus some things that could be simplified and improved: * 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit path, so it was only doing anything with it once it saw some other bit being set. In other words, the noerror behaviour would apply to the next system call where we had to reschedule or deliver a signal, which is not necessarily the current system call. * 32-bit wasn't doing the call to ptrace_notify in the syscall exit path when the _TIF_SINGLESTEP bit was set. * _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and _TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set by system calls. I took it out of _TIF_USER_WORK_MASK. * On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers to be restored (unless perhaps a signal was delivered or the syscall was traced or single-stepped). Thus the non-volatile registers weren't restored on exit from a signal handler. We probably got away with it mostly because signal handlers written in C wouldn't alter the non-volatile registers. * On 32-bit I simplified the code and made it more like 64-bit by making the syscall exit path jump to ret_from_except to handle preemption and signal delivery. * 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was set - but I think because of that 32-bit was actually restoring the non-volatile registers on exit from a signal handler. * I changed the order of enabling interrupts and saving the non-volatile registers before calling do_syscall_trace_leave; now we enable interrupts first. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-08 10:24:22 +08:00
/* Clear per-syscall TIF flags if any are set. */
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
li r11,_TIF_PERSYSCALL_MASK
addi r12,r12,TI_FLAGS
3: ldarx r10,0,r12
andc r10,r10,r11
stdcx. r10,0,r12
bne- 3b
subi r12,r12,TI_FLAGS
powerpc: Fix various syscall/signal/swapcontext bugs A careful reading of the recent changes to the system call entry/exit paths revealed several problems, plus some things that could be simplified and improved: * 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit path, so it was only doing anything with it once it saw some other bit being set. In other words, the noerror behaviour would apply to the next system call where we had to reschedule or deliver a signal, which is not necessarily the current system call. * 32-bit wasn't doing the call to ptrace_notify in the syscall exit path when the _TIF_SINGLESTEP bit was set. * _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and _TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set by system calls. I took it out of _TIF_USER_WORK_MASK. * On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers to be restored (unless perhaps a signal was delivered or the syscall was traced or single-stepped). Thus the non-volatile registers weren't restored on exit from a signal handler. We probably got away with it mostly because signal handlers written in C wouldn't alter the non-volatile registers. * On 32-bit I simplified the code and made it more like 64-bit by making the syscall exit path jump to ret_from_except to handle preemption and signal delivery. * 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was set - but I think because of that 32-bit was actually restoring the non-volatile registers on exit from a signal handler. * I changed the order of enabling interrupts and saving the non-volatile registers before calling do_syscall_trace_leave; now we enable interrupts first. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-08 10:24:22 +08:00
4: /* Anything else left to do? */
powerpc/kernel: Open code SET_DEFAULT_THREAD_PPR This is only used in one location, open code it. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-11-25 11:25:18 +08:00
BEGIN_FTR_SECTION
lis r3,INIT_PPR@highest /* Set thread.ppr = 3 */
ld r10,PACACURRENT(r13)
sldi r3,r3,32 /* bits 11-13 are used for ppr */
std r3,TASKTHREADPPR(r10)
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
powerpc: Rename _TIF_SYSCALL_T_OR_A to _TIF_SYSCALL_DOTRACE Once upon a time, at least 9 years ago (< 2.6.12), _TIF_SYSCALL_T_OR_A meant "TRACE or AUDIT". But these days it means TRACE or AUDIT or SECCOMP or TRACEPOINT or NOHZ. All of those are implemented via syscall_dotrace() so rename the flag to that to try and clarify things. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-01-15 09:01:42 +08:00
andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
beq ret_from_except_lite
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
/* Re-enable interrupts */
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#ifdef CONFIG_PPC_BOOK3E
wrteei 1
#else
powerpc/64s: Optimise MSR handling in exception handling mtmsrd with L=1 only affects MSR_EE and MSR_RI bits, and we always know what state those bits are, so the kernel MSR does not need to be loaded when modifying them. mtmsrd is often in the critical execution path, so avoiding dependency on even L1 load is noticable. On a POWER8 this saves about 3 cycles from the syscall path, and possibly a few from other exception returns (not measured). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-15 17:04:46 +08:00
li r10,MSR_RI
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
ori r10,r10,MSR_EE
mtmsrd r10,1
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#endif /* CONFIG_PPC_BOOK3E */
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl save_nvgprs
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
addi r3,r1,STACK_FRAME_OVERHEAD
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl do_syscall_trace_leave
b ret_from_except
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
.Ltabort_syscall:
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
/* Firstly we need to enable TM in the kernel */
mfmsr r10
powerpc/tm: do not use r13 for tabort_syscall tabort_syscall runs with RI=1, so a nested recoverable machine check will load the paca into r13 and overwrite what we loaded it with, because exceptions returning to privileged mode do not restore r13. Fixes: b4b56f9ecab4 (powerpc/tm: Abort syscalls in active transactions) Cc: stable@vger.kernel.org Signed-off-by: Nick Piggin <npiggin@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2016-07-25 12:26:51 +08:00
li r9, 1
rldimi r10, r9, MSR_TM_LG, 63-MSR_TM_LG
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
mtmsrd r10, 0
/* tabort, this dooms the transaction, nothing else */
powerpc/tm: do not use r13 for tabort_syscall tabort_syscall runs with RI=1, so a nested recoverable machine check will load the paca into r13 and overwrite what we loaded it with, because exceptions returning to privileged mode do not restore r13. Fixes: b4b56f9ecab4 (powerpc/tm: Abort syscalls in active transactions) Cc: stable@vger.kernel.org Signed-off-by: Nick Piggin <npiggin@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2016-07-25 12:26:51 +08:00
li r9, (TM_CAUSE_SYSCALL|TM_CAUSE_PERSISTENT)
TABORT(R9)
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
/*
* Return directly to userspace. We have corrupted user register state,
* but userspace will never see that register state. Execution will
* resume after the tbegin of the aborted transaction with the
* checkpointed register state.
*/
powerpc/tm: do not use r13 for tabort_syscall tabort_syscall runs with RI=1, so a nested recoverable machine check will load the paca into r13 and overwrite what we loaded it with, because exceptions returning to privileged mode do not restore r13. Fixes: b4b56f9ecab4 (powerpc/tm: Abort syscalls in active transactions) Cc: stable@vger.kernel.org Signed-off-by: Nick Piggin <npiggin@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2016-07-25 12:26:51 +08:00
li r9, MSR_RI
andc r10, r10, r9
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
mtmsrd r10, 1
mtspr SPRN_SRR0, r11
mtspr SPRN_SRR1, r12
rfid
b . /* prevent speculative execution */
#endif
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:16 +08:00
_ASM_NOKPROBE_SYMBOL(system_call_common);
powerpc/64s: Un-blacklist system_call() from kprobes It is actually safe to probe system_call() in entry_64.S, but only till we unset MSR_RI. To allow this, add a new symbol system_call_exit() after the mtmsrd and blacklist that. Suggested-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:18 +08:00
_ASM_NOKPROBE_SYMBOL(system_call_exit);
powerpc/tm: Abort syscalls in active transactions This patch changes the syscall handler to doom (tabort) active transactions when a syscall is made and return very early without performing the syscall and keeping side effects to a minimum (no CPU accounting or system call tracing is performed). Also included is a new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this behaviour to userspace. Currently, the system call instruction automatically suspends an active transaction which causes side effects to persist when an active transaction fails. This does change the kernel's behaviour, but in a way that was documented as unsupported. It doesn't reduce functionality as syscalls will still be performed after tsuspend; it just requires that the transaction be explicitly suspended. It also provides a consistent interface and makes the behaviour of user code substantially the same across powerpc and platforms that do not support suspended transactions (e.g. x86 and s390). Performance measurements using http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of a normal (non-aborted) system call increases by about 0.25%. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-12 09:06:32 +08:00
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* Save non-volatile GPRs, if not already saved. */
_GLOBAL(save_nvgprs)
ld r11,_TRAP(r1)
andi. r0,r11,1
beqlr-
SAVE_NVGPRS(r1)
clrrdi r0,r11,1
std r0,_TRAP(r1)
blr
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
_ASM_NOKPROBE_SYMBOL(save_nvgprs);
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 02:52:18 +08:00
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/*
* The sigsuspend and rt_sigsuspend system calls can call do_signal
* and thus put the process into the stopped state where we might
* want to examine its user state with ptrace. Therefore we need
* to save all the nonvolatile registers (r14 - r31) before calling
* the C code. Similarly, fork, vfork and clone need the full
* register state on the stack so that it can be copied to the child.
*/
_GLOBAL(ppc_fork)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl save_nvgprs
bl sys_fork
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
b .Lsyscall_exit
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
_GLOBAL(ppc_vfork)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl save_nvgprs
bl sys_vfork
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
b .Lsyscall_exit
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
_GLOBAL(ppc_clone)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl save_nvgprs
bl sys_clone
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
b .Lsyscall_exit
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: Fix various syscall/signal/swapcontext bugs A careful reading of the recent changes to the system call entry/exit paths revealed several problems, plus some things that could be simplified and improved: * 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit path, so it was only doing anything with it once it saw some other bit being set. In other words, the noerror behaviour would apply to the next system call where we had to reschedule or deliver a signal, which is not necessarily the current system call. * 32-bit wasn't doing the call to ptrace_notify in the syscall exit path when the _TIF_SINGLESTEP bit was set. * _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and _TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set by system calls. I took it out of _TIF_USER_WORK_MASK. * On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers to be restored (unless perhaps a signal was delivered or the syscall was traced or single-stepped). Thus the non-volatile registers weren't restored on exit from a signal handler. We probably got away with it mostly because signal handlers written in C wouldn't alter the non-volatile registers. * On 32-bit I simplified the code and made it more like 64-bit by making the syscall exit path jump to ret_from_except to handle preemption and signal delivery. * 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was set - but I think because of that 32-bit was actually restoring the non-volatile registers on exit from a signal handler. * I changed the order of enabling interrupts and saving the non-volatile registers before calling do_syscall_trace_leave; now we enable interrupts first. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-08 10:24:22 +08:00
_GLOBAL(ppc32_swapcontext)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl save_nvgprs
bl compat_sys_swapcontext
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
b .Lsyscall_exit
powerpc: Fix various syscall/signal/swapcontext bugs A careful reading of the recent changes to the system call entry/exit paths revealed several problems, plus some things that could be simplified and improved: * 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit path, so it was only doing anything with it once it saw some other bit being set. In other words, the noerror behaviour would apply to the next system call where we had to reschedule or deliver a signal, which is not necessarily the current system call. * 32-bit wasn't doing the call to ptrace_notify in the syscall exit path when the _TIF_SINGLESTEP bit was set. * _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and _TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set by system calls. I took it out of _TIF_USER_WORK_MASK. * On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers to be restored (unless perhaps a signal was delivered or the syscall was traced or single-stepped). Thus the non-volatile registers weren't restored on exit from a signal handler. We probably got away with it mostly because signal handlers written in C wouldn't alter the non-volatile registers. * On 32-bit I simplified the code and made it more like 64-bit by making the syscall exit path jump to ret_from_except to handle preemption and signal delivery. * 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was set - but I think because of that 32-bit was actually restoring the non-volatile registers on exit from a signal handler. * I changed the order of enabling interrupts and saving the non-volatile registers before calling do_syscall_trace_leave; now we enable interrupts first. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-08 10:24:22 +08:00
_GLOBAL(ppc64_swapcontext)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl save_nvgprs
bl sys_swapcontext
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
b .Lsyscall_exit
powerpc: Fix various syscall/signal/swapcontext bugs A careful reading of the recent changes to the system call entry/exit paths revealed several problems, plus some things that could be simplified and improved: * 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit path, so it was only doing anything with it once it saw some other bit being set. In other words, the noerror behaviour would apply to the next system call where we had to reschedule or deliver a signal, which is not necessarily the current system call. * 32-bit wasn't doing the call to ptrace_notify in the syscall exit path when the _TIF_SINGLESTEP bit was set. * _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and _TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set by system calls. I took it out of _TIF_USER_WORK_MASK. * On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers to be restored (unless perhaps a signal was delivered or the syscall was traced or single-stepped). Thus the non-volatile registers weren't restored on exit from a signal handler. We probably got away with it mostly because signal handlers written in C wouldn't alter the non-volatile registers. * On 32-bit I simplified the code and made it more like 64-bit by making the syscall exit path jump to ret_from_except to handle preemption and signal delivery. * 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was set - but I think because of that 32-bit was actually restoring the non-volatile registers on exit from a signal handler. * I changed the order of enabling interrupts and saving the non-volatile registers before calling do_syscall_trace_leave; now we enable interrupts first. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-08 10:24:22 +08:00
powerpc: Add a proper syscall for switching endianness We currently have a "special" syscall for switching endianness. This is syscall number 0x1ebe, which is handled explicitly in the 64-bit syscall exception entry. That has a few problems, firstly the syscall number is outside of the usual range, which confuses various tools. For example strace doesn't recognise the syscall at all. Secondly it's handled explicitly as a special case in the syscall exception entry, which is complicated enough without it. As a first step toward removing the special syscall, we need to add a regular syscall that implements the same functionality. The logic is simple, it simply toggles the MSR_LE bit in the userspace MSR. This is the same as the special syscall, with the caveat that the special syscall clobbers fewer registers. This version clobbers r9-r12, XER, CTR, and CR0-1,5-7. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-03-28 18:35:16 +08:00
_GLOBAL(ppc_switch_endian)
bl save_nvgprs
bl sys_switch_endian
b .Lsyscall_exit
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
_GLOBAL(ret_from_fork)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl schedule_tail
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
REST_NVGPRS(r1)
li r3,0
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
b .Lsyscall_exit
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: split ret_from_fork ... and get rid of in-kernel syscalls in kernel_thread() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-13 06:32:42 +08:00
_GLOBAL(ret_from_kernel_thread)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl schedule_tail
powerpc: split ret_from_fork ... and get rid of in-kernel syscalls in kernel_thread() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-13 06:32:42 +08:00
REST_NVGPRS(r1)
mtlr r14
mr r3,r15
powerpc: Define and use PPC64_ELF_ABI_v2/v1 We're approaching 20 locations where we need to check for ELF ABI v2. That's fine, except the logic is a bit awkward, because we have to check that _CALL_ELF is defined and then what its value is. So check it once in asm/types.h and define PPC64_ELF_ABI_v2 when ELF ABI v2 is detected. We also have a few places where what we're really trying to check is that we are using the 64-bit v1 ABI, ie. function descriptors. So also add a #define for that, which simplifies several checks. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-06-07 00:56:10 +08:00
#ifdef PPC64_ELF_ABI_v2
powerpc: Fix kernel thread creation on ABIv2 Change how we setup registers for ret_from_kernel_thread. In ABIv1, instead of passing a function descriptor in, dereference it and pass the target in directly. Use ppc_global_function_entry to get it right on both ABIv1 and ABIv2. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:08:51 +08:00
mr r12,r14
#endif
powerpc: split ret_from_fork ... and get rid of in-kernel syscalls in kernel_thread() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-13 06:32:42 +08:00
blrl
li r3,0
powerpc/kernel: Make syscall_exit a local label Currently when we back trace something that is in a syscall we see something like this: [c000000000000000] [c000000000000000] SyS_read+0x6c/0x110 [c000000000000000] [c000000000000000] syscall_exit+0x0/0x98 Although it's entirely correct, seeing syscall_exit at the bottom can be confusing - we were exiting from a syscall and then called SyS_read() ? If we instead change syscall_exit to be a local label we get something more intuitive: [c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110 [c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0 ie. we were handling a system call, and it was SyS_read(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 18:16:59 +08:00
b .Lsyscall_exit
powerpc: switch to generic sys_execve()/kernel_execve() the only non-obvious part is that current_pt_regs() is really needed here - task_pt_regs() is NULL for kernel threads; it's OK for ptrace uses (the thing task_pt_regs() is intended for), but not for us. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-01 03:48:05 +08:00
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/*
* This routine switches between two different tasks. The process
* state of one is saved on its kernel stack. Then the state
* of the other is restored from its kernel stack. The memory
* management hardware is updated to the second process's state.
* Finally, we can return to the second process, via ret_from_except.
* On entry, r3 points to the THREAD for the current task, r4
* points to the THREAD for the new task.
*
* Note: there are two ways to get to the "going out" portion
* of this code; either by coming in via the entry (_switch)
* or via "fork" which must set up an environment equivalent
* to the "_switch" path. If you change this you'll have to change
* the fork code also.
*
* The code which creates the new task context is in 'copy_thread'
[PATCH] powerpc: trivial: modify comments to refer to new location of files This patch removes all self references and fixes references to files in the now defunct arch/ppc64 tree. I think this accomplises everything wanted, though there might be a few references I missed. Signed-off-by: Jon Mason <jdmason@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-24 00:58:20 +08:00
* in arch/powerpc/kernel/process.c
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
*/
.align 7
_GLOBAL(_switch)
mflr r0
std r0,16(r1)
stdu r1,-SWITCH_FRAME_SIZE(r1)
/* r3-r13 are caller saved -- Cort */
SAVE_8GPRS(14, r1)
SAVE_10GPRS(22, r1)
powerpc: Remove redundant mflr in _switch No need to execute mflr twice. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-10-29 08:43:56 +08:00
std r0,_NIP(r1) /* Return to switch caller */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
mfcr r23
std r23,_CCR(r1)
std r1,KSP(r3) /* Set old stack pointer */
powerpc/64: Drop explicit hwsync in context switch The sync (aka. hwsync, aka. heavyweight sync) in the context switch code to prevent MMIO access being reordered from the point of view of a single process if it gets migrated to a different CPU is not required because there is an hwsync performed earlier in the context switch path. Comment this so it's clear enough if anything changes on the scheduler or the powerpc sides. Remove the hwsync from _switch. This improves context switch performance by 2-3% on POWER8. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:36:08 +08:00
/*
* On SMP kernels, care must be taken because a task may be
* scheduled off CPUx and on to CPUy. Memory ordering must be
* considered.
*
* Cacheable stores on CPUx will be visible when the task is
* scheduled on CPUy by virtue of the core scheduler barriers
* (see "Notes on Program-Order guarantees on SMP systems." in
* kernel/sched/core.c).
*
* Uncacheable stores in the case of involuntary preemption must
* be taken care of. The smp_mb__before_spin_lock() in __schedule()
* is implemented as hwsync on powerpc, which orders MMIO too. So
* long as there is an hwsync in the context switch path, it will
* be executed on the source CPU after the task has performed
* all MMIO ops on that CPU, and on the destination CPU before the
* task performs any MMIO ops there.
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
*/
powerpc: Feature nop out reservation clear when stcx checks address The POWER architecture does not require stcx to check that it is operating on the same address as the larx. This means it is possible for an an exception handler to execute a larx, get a reservation, decide not to do the stcx and then return back with an active reservation. If the interrupted code was in the middle of a larx/stcx sequence the stcx could incorrectly succeed. All recent POWER CPUs check the address before letting the stcx succeed so we can create a CPU feature and nop it out. As Ben suggested, we can only do this in our syscall path because there is a remote possibility some kernel code gets interrupted by an exception that ends up operating on the same cacheline. Thanks to Paul Mackerras and Derek Williams for the idea. To test this I used a very simple null syscall (actually getppid) testcase at http://ozlabs.org/~anton/junkcode/null_syscall.c I tested against 2.6.35-git10 with the following changes against the pseries_defconfig: CONFIG_VIRT_CPU_ACCOUNTING=n CONFIG_AUDIT=n CONFIG_PPC_4K_PAGES=n CONFIG_PPC_64K_PAGES=y CONFIG_FORCE_MAX_ZONEORDER=9 CONFIG_PPC_SUBPAGE_PROT=n CONFIG_FUNCTION_TRACER=n CONFIG_FUNCTION_GRAPH_TRACER=n CONFIG_IRQSOFF_TRACER=n CONFIG_STACK_TRACER=n to remove the overhead of virtual CPU accounting, syscall auditing and the ftrace mcount tracers. 64kB pages were enabled to minimise TLB misses. POWER6: +8.2% POWER7: +7.0% Another suggestion was to use a larx to something in the L1 instead of a stcx. This was almost as fast as removing the larx on POWER6, but only 3.5% faster on POWER7. We can use this to speed up the reservation clear in our exception exit code. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-11 09:40:27 +08:00
/*
powerpc/64: Drop reservation-clearing ldarx in context switch There is no need to explicitly break the reservation in _switch, because we are guaranteed that the context switch path will include a larx/stcx. Comment the guarantee and remove the reservation clear from _switch. This is worth 1-2% in context switch performance. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:36:07 +08:00
* The kernel context switch path must contain a spin_lock,
* which contains larx/stcx, which will clear any reservation
* of the task being switched.
powerpc: Feature nop out reservation clear when stcx checks address The POWER architecture does not require stcx to check that it is operating on the same address as the larx. This means it is possible for an an exception handler to execute a larx, get a reservation, decide not to do the stcx and then return back with an active reservation. If the interrupted code was in the middle of a larx/stcx sequence the stcx could incorrectly succeed. All recent POWER CPUs check the address before letting the stcx succeed so we can create a CPU feature and nop it out. As Ben suggested, we can only do this in our syscall path because there is a remote possibility some kernel code gets interrupted by an exception that ends up operating on the same cacheline. Thanks to Paul Mackerras and Derek Williams for the idea. To test this I used a very simple null syscall (actually getppid) testcase at http://ozlabs.org/~anton/junkcode/null_syscall.c I tested against 2.6.35-git10 with the following changes against the pseries_defconfig: CONFIG_VIRT_CPU_ACCOUNTING=n CONFIG_AUDIT=n CONFIG_PPC_4K_PAGES=n CONFIG_PPC_64K_PAGES=y CONFIG_FORCE_MAX_ZONEORDER=9 CONFIG_PPC_SUBPAGE_PROT=n CONFIG_FUNCTION_TRACER=n CONFIG_FUNCTION_GRAPH_TRACER=n CONFIG_IRQSOFF_TRACER=n CONFIG_STACK_TRACER=n to remove the overhead of virtual CPU accounting, syscall auditing and the ftrace mcount tracers. 64kB pages were enabled to minimise TLB misses. POWER6: +8.2% POWER7: +7.0% Another suggestion was to use a larx to something in the L1 instead of a stcx. This was almost as fast as removing the larx on POWER6, but only 3.5% faster on POWER7. We can use this to speed up the reservation clear in our exception exit code. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-08-11 09:40:27 +08:00
*/
powerpc/pseries: Kill all prefetch streams on context switch On context switch, we should have no prefetch streams leak from one userspace process to another. This frees up prefetch resources for the next process. Based on patch from Milton Miller. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-30 03:34:27 +08:00
#ifdef CONFIG_PPC_BOOK3S
/* Cancel all explict user streams as they will have no use after context
* switch and will stop the HW from creating streams itself
*/
DCBT_STOP_ALL_STREAM_IDS(r6)
#endif
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
addi r6,r4,-THREAD /* Convert THREAD to 'current' */
std r6,PACACURRENT(r13) /* Set new 'current' */
ld r8,KSP(r4) /* new stack pointer */
powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code We also use MMU_FTR_RADIX to branch out from code path specific to hash. No functionality change. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-04-29 21:26:07 +08:00
#ifdef CONFIG_PPC_STD_MMU_64
BEGIN_MMU_FTR_SECTION
b 2f
powerpc/mm: Make MMU_FTR_RADIX a MMU family feature MMU feature bits are defined such that we use the lower half to present MMU family features. Remove the strict split of half and also move Radix to a mmu family feature. Radix introduce a new MMU model and strictly speaking it is a new MMU family. This also free up bits which can be used for individual features later. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-27 11:19:01 +08:00
END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX)
[POWERPC] Use 1TB segments This makes the kernel use 1TB segments for all kernel mappings and for user addresses of 1TB and above, on machines which support them (currently POWER5+, POWER6 and PA6T). We detect that the machine supports 1TB segments by looking at the ibm,processor-segment-sizes property in the device tree. We don't currently use 1TB segments for user addresses < 1T, since that would effectively prevent 32-bit processes from using huge pages unless we also had a way to revert to using 256MB segments. That would be possible but would involve extra complications (such as keeping track of which segment size was used when HPTEs were inserted) and is not addressed here. Parts of this patch were originally written by Ben Herrenschmidt. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-11 18:37:10 +08:00
BEGIN_FTR_SECTION
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
clrrdi r6,r8,28 /* get its ESID */
clrrdi r9,r1,28 /* get current sp ESID */
powerpc: Remove MMU_FTR_SLB We now only support cpus that use an SLB, so we don't need an MMU feature to indicate that. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-10 10:29:20 +08:00
FTR_SECTION_ELSE
[POWERPC] Use 1TB segments This makes the kernel use 1TB segments for all kernel mappings and for user addresses of 1TB and above, on machines which support them (currently POWER5+, POWER6 and PA6T). We detect that the machine supports 1TB segments by looking at the ibm,processor-segment-sizes property in the device tree. We don't currently use 1TB segments for user addresses < 1T, since that would effectively prevent 32-bit processes from using huge pages unless we also had a way to revert to using 256MB segments. That would be possible but would involve extra complications (such as keeping track of which segment size was used when HPTEs were inserted) and is not addressed here. Parts of this patch were originally written by Ben Herrenschmidt. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-11 18:37:10 +08:00
clrrdi r6,r8,40 /* get its 1T ESID */
clrrdi r9,r1,40 /* get current sp 1T ESID */
powerpc: Remove MMU_FTR_SLB We now only support cpus that use an SLB, so we don't need an MMU feature to indicate that. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-10 10:29:20 +08:00
ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_1T_SEGMENT)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
clrldi. r0,r6,2 /* is new ESID c00000000? */
cmpd cr1,r6,r9 /* or is new ESID the same as current ESID? */
cror eq,4*cr1+eq,eq
beq 2f /* if yes, don't slbie it */
/* Bolt in the new stack SLB entry */
ld r7,KSP_VSID(r4) /* Get new stack's VSID */
oris r0,r6,(SLB_ESID_V)@h
ori r0,r0,(SLB_NUM_BOLTED-1)@l
[POWERPC] Use 1TB segments This makes the kernel use 1TB segments for all kernel mappings and for user addresses of 1TB and above, on machines which support them (currently POWER5+, POWER6 and PA6T). We detect that the machine supports 1TB segments by looking at the ibm,processor-segment-sizes property in the device tree. We don't currently use 1TB segments for user addresses < 1T, since that would effectively prevent 32-bit processes from using huge pages unless we also had a way to revert to using 256MB segments. That would be possible but would involve extra complications (such as keeping track of which segment size was used when HPTEs were inserted) and is not addressed here. Parts of this patch were originally written by Ben Herrenschmidt. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-11 18:37:10 +08:00
BEGIN_FTR_SECTION
li r9,MMU_SEGSIZE_1T /* insert B field */
oris r6,r6,(MMU_SEGSIZE_1T << SLBIE_SSIZE_SHIFT)@h
rldimi r7,r9,SLB_VSID_SSIZE_SHIFT,0
powerpc: Free up some CPU feature bits by moving out MMU-related features Some of the 64bit PPC CPU features are MMU-related, so this patch moves them to MMU_FTR_ bits. All cpu_has_feature()-style tests are moved to mmu_has_feature(), and seven feature bits are freed as a result. Signed-off-by: Matt Evans <matt@ozlabs.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-07 03:48:50 +08:00
END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
[POWERPC] Implement SLB shadow buffer This adds a shadow buffer for the SLBs and regsiters it with PHYP. Only the bolted SLB entries (top 3) are shadowed. The SLB shadow buffer tells the hypervisor what the kernel needs to have in the SLB for the kernel to be able to function. The hypervisor can use this information to speed up partition context switches. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-08-07 14:19:19 +08:00
[POWERPC] Remove barriers from the SLB shadow buffer update After talking to an IBM POWER hypervisor (PHYP) design and development guy, there seems to be no need for memory barriers when updating the SLB shadow buffer provided we only update it from the current CPU, which we do. Also, these guys see no need in the future for these barriers. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-08-24 14:58:37 +08:00
/* Update the last bolted SLB. No write barriers are needed
* here, provided we only update the current CPU's SLB shadow
* buffer.
*/
[POWERPC] Implement SLB shadow buffer This adds a shadow buffer for the SLBs and regsiters it with PHYP. Only the bolted SLB entries (top 3) are shadowed. The SLB shadow buffer tells the hypervisor what the kernel needs to have in the SLB for the kernel to be able to function. The hypervisor can use this information to speed up partition context switches. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-08-07 14:19:19 +08:00
ld r9,PACA_SLBSHADOWPTR(r13)
[POWERPC] SLB shadow buffer cleanup Cleanup some of the #define magic as suggested by Milton. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-08-09 15:00:30 +08:00
li r12,0
powerpc: Fix little endian lppaca, slb_shadow and dtl_entry The lppaca, slb_shadow and dtl_entry hypervisor structures are big endian, so we have to byte swap them in little endian builds. LE KVM hosts will also need to be fixed but for now add an #error to remind us. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-08-07 00:01:46 +08:00
std r12,SLBSHADOW_STACKESID(r9) /* Clear ESID */
li r12,SLBSHADOW_STACKVSID
STDX_BE r7,r12,r9 /* Save VSID */
li r12,SLBSHADOW_STACKESID
STDX_BE r0,r12,r9 /* Save ESID */
[POWERPC] Implement SLB shadow buffer This adds a shadow buffer for the SLBs and regsiters it with PHYP. Only the bolted SLB entries (top 3) are shadowed. The SLB shadow buffer tells the hypervisor what the kernel needs to have in the SLB for the kernel to be able to function. The hypervisor can use this information to speed up partition context switches. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-08-07 14:19:19 +08:00
powerpc: Free up some CPU feature bits by moving out MMU-related features Some of the 64bit PPC CPU features are MMU-related, so this patch moves them to MMU_FTR_ bits. All cpu_has_feature()-style tests are moved to mmu_has_feature(), and seven feature bits are freed as a result. Signed-off-by: Matt Evans <matt@ozlabs.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-07 03:48:50 +08:00
/* No need to check for MMU_FTR_NO_SLBIE_B here, since when
[POWERPC] Add 1TB workaround for PA6T PA6T has a bug where the slbie instruction does not honor the large segment bit. As a result, we have to always use slbia when switching context. We don't have to worry about changing the slbie's during fault processing, since they should never be replacing one VSID with another using the same ESID. I.e. there's no risk for inserting duplicate entries due to a failed slbie of the old entry. So as long as we clear it out on context switch we should be fine. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-15 22:58:59 +08:00
* we have 1TB segments, the only CPUs known to have the errata
* only support less than 1TB of system memory and we'll never
* actually hit this code path.
*/
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
slbie r6
slbie r6 /* Workaround POWER5 < DD2.1 issue */
slbmte r7,r0
isync
2:
powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code We also use MMU_FTR_RADIX to branch out from code path specific to hash. No functionality change. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-04-29 21:26:07 +08:00
#endif /* CONFIG_PPC_STD_MMU_64 */
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
powerpc: Use CURRENT_THREAD_INFO instead of open coded assembly Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-05 12:41:35 +08:00
CURRENT_THREAD_INFO(r7, r8) /* base of new stack */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
because we don't need to leave the 288-byte ABI gap at the
top of the kernel stack. */
addi r7,r7,THREAD_SIZE-SWITCH_FRAME_SIZE
powerpc/64s: Leave interrupts hard enabled in context switch for radix Commit 4387e9ff25 ("[POWERPC] Fix PMU + soft interrupt disable bug") hard disabled interrupts over the low level context switch, because the SLB management can't cope with a PMU interrupt accesing the stack in that window. Radix based kernel mapping does not use the SLB so it does not require interrupts hard disabled here. This is worth 1-2% in context switch performance on POWER9. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 23:36:06 +08:00
/*
* PMU interrupts in radix may come in here. They will use r1, not
* PACAKSAVE, so this stack switch will not cause a problem. They
* will store to the process stack, which may then be migrated to
* another CPU. However the rq lock release on this CPU paired with
* the rq lock acquire on the new CPU before the stack becomes
* active on the new CPU, will order those stores.
*/
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
mr r1,r8 /* start using new stack pointer */
std r7,PACAKSAVE(r13)
powerpc: Restore correct DSCR in context switch During a context switch we always restore the per thread DSCR value. If we aren't doing explicit DSCR management (ie thread.dscr_inherit == 0) and the default DSCR changed while the process has been sleeping we end up with the wrong value. Check thread.dscr_inherit and select the default DSCR or per thread DSCR as required. This was found with the following test case, when running with more threads than CPUs (ie forcing context switching): http://ozlabs.org/~anton/junkcode/dscr_default_test.c With the four patches applied I can run a combination of all test cases successfully at the same time: http://ozlabs.org/~anton/junkcode/dscr_default_test.c http://ozlabs.org/~anton/junkcode/dscr_explicit_test.c http://ozlabs.org/~anton/junkcode/dscr_inherit_test.c Signed-off-by: Anton Blanchard <anton@samba.org> Cc: <stable@kernel.org> # 3.0+ Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-04 00:51:10 +08:00
ld r6,_CCR(r1)
mtcrf 0xFF,r6
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* r3-r13 are destroyed -- Cort */
REST_8GPRS(14, r1)
REST_10GPRS(22, r1)
/* convert old thread to its task_struct for return value */
addi r3,r3,-THREAD
ld r7,_NIP(r1) /* Return to _switch caller in new task */
mtlr r7
addi r1,r1,SWITCH_FRAME_SIZE
blr
.align 7
_GLOBAL(ret_from_except)
ld r11,_TRAP(r1)
andi. r0,r11,1
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bne ret_from_except_lite
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
REST_NVGPRS(r1)
_GLOBAL(ret_from_except_lite)
/*
* Disable interrupts so that current_thread_info()->flags
* can't change between when we test it and when we return
* from the interrupt.
*/
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#ifdef CONFIG_PPC_BOOK3E
wrteei 0
#else
powerpc/64s: Optimise MSR handling in exception handling mtmsrd with L=1 only affects MSR_EE and MSR_RI bits, and we always know what state those bits are, so the kernel MSR does not need to be loaded when modifying them. mtmsrd is often in the critical execution path, so avoiding dependency on even L1 load is noticable. On a POWER8 this saves about 3 cycles from the syscall path, and possibly a few from other exception returns (not measured). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-15 17:04:46 +08:00
li r10,MSR_RI
powerpc: Replace mfmsr instructions with load from PACA kernel_msr field On 64-bit, the mfmsr instruction can be quite slow, slower than loading a field from the cache-hot PACA, which happens to already contain the value we want in most cases. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-02 08:33:52 +08:00
mtmsrd r10,1 /* Update machine state */
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#endif /* CONFIG_PPC_BOOK3E */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: Use CURRENT_THREAD_INFO instead of open coded assembly Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-05 12:41:35 +08:00
CURRENT_THREAD_INFO(r9, r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r3,_MSR(r1)
powerpc: Restore dbcr0 on user space exit On BookE (Branch taken + Single Step) is as same as Branch Taken on BookS and in Linux we simulate BookS behavior for BookE as well. When doing so, in Branch taken handling we want to set DBCR0_IC but we update the current->thread->dbcr0 and not DBCR0. Now on 64bit the current->thread.dbcr0 (and other debug registers) is synchronized ONLY on context switch flow. But after handling Branch taken in debug exception if we return back to user space without context switch then single stepping change (DBCR0_ICMP) does not get written in h/w DBCR0 and Instruction Complete exception does not happen. This fixes using ptrace reliably on BookE-PowerPC lmbench latency test (lat_syscall) Results are (they varies a little on each run) 1) ./lat_syscall <action> /dev/shm/uImage action: Open read write stat fstat null Before: 3.8618 0.2017 0.2851 1.6789 0.2256 0.0856 After: 3.8580 0.2017 0.2851 1.6955 0.2255 0.0856 1) ./lat_syscall -P 2 -N 10 <action> /dev/shm/uImage action: Open read write stat fstat null Before: 4.1388 0.2238 0.3066 1.7106 0.2256 0.0856 After: 4.1413 0.2236 0.3062 1.7107 0.2256 0.0856 [ Slightly modified to avoid extra branch in the fast path on Book3S and fix build on all non-BookE 64-bit -- BenH ] Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-22 12:20:59 +08:00
#ifdef CONFIG_PPC_BOOK3E
ld r10,PACACURRENT(r13)
#endif /* CONFIG_PPC_BOOK3E */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r4,TI_FLAGS(r9)
andi. r3,r3,MSR_PR
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
beq resume_kernel
powerpc: Restore dbcr0 on user space exit On BookE (Branch taken + Single Step) is as same as Branch Taken on BookS and in Linux we simulate BookS behavior for BookE as well. When doing so, in Branch taken handling we want to set DBCR0_IC but we update the current->thread->dbcr0 and not DBCR0. Now on 64bit the current->thread.dbcr0 (and other debug registers) is synchronized ONLY on context switch flow. But after handling Branch taken in debug exception if we return back to user space without context switch then single stepping change (DBCR0_ICMP) does not get written in h/w DBCR0 and Instruction Complete exception does not happen. This fixes using ptrace reliably on BookE-PowerPC lmbench latency test (lat_syscall) Results are (they varies a little on each run) 1) ./lat_syscall <action> /dev/shm/uImage action: Open read write stat fstat null Before: 3.8618 0.2017 0.2851 1.6789 0.2256 0.0856 After: 3.8580 0.2017 0.2851 1.6955 0.2255 0.0856 1) ./lat_syscall -P 2 -N 10 <action> /dev/shm/uImage action: Open read write stat fstat null Before: 4.1388 0.2238 0.3066 1.7106 0.2256 0.0856 After: 4.1413 0.2236 0.3062 1.7107 0.2256 0.0856 [ Slightly modified to avoid extra branch in the fast path on Book3S and fix build on all non-BookE 64-bit -- BenH ] Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-22 12:20:59 +08:00
#ifdef CONFIG_PPC_BOOK3E
lwz r3,(THREAD+THREAD_DBCR0)(r10)
#endif /* CONFIG_PPC_BOOK3E */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* Check current_thread_info()->flags */
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
andi. r0,r4,_TIF_USER_WORK_MASK
powerpc: Restore dbcr0 on user space exit On BookE (Branch taken + Single Step) is as same as Branch Taken on BookS and in Linux we simulate BookS behavior for BookE as well. When doing so, in Branch taken handling we want to set DBCR0_IC but we update the current->thread->dbcr0 and not DBCR0. Now on 64bit the current->thread.dbcr0 (and other debug registers) is synchronized ONLY on context switch flow. But after handling Branch taken in debug exception if we return back to user space without context switch then single stepping change (DBCR0_ICMP) does not get written in h/w DBCR0 and Instruction Complete exception does not happen. This fixes using ptrace reliably on BookE-PowerPC lmbench latency test (lat_syscall) Results are (they varies a little on each run) 1) ./lat_syscall <action> /dev/shm/uImage action: Open read write stat fstat null Before: 3.8618 0.2017 0.2851 1.6789 0.2256 0.0856 After: 3.8580 0.2017 0.2851 1.6955 0.2255 0.0856 1) ./lat_syscall -P 2 -N 10 <action> /dev/shm/uImage action: Open read write stat fstat null Before: 4.1388 0.2238 0.3066 1.7106 0.2256 0.0856 After: 4.1413 0.2236 0.3062 1.7107 0.2256 0.0856 [ Slightly modified to avoid extra branch in the fast path on Book3S and fix build on all non-BookE 64-bit -- BenH ] Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-22 12:20:59 +08:00
bne 1f
powerpc: Restore FPU/VEC/VSX if previously used Currently the FPU, VEC and VSX facilities are lazily loaded. This is not a problem unless a process is using these facilities. Modern versions of GCC are very good at automatically vectorising code, new and modernised workloads make use of floating point and vector facilities, even the kernel makes use of vectorised memcpy. All this combined greatly increases the cost of a syscall since the kernel uses the facilities sometimes even in syscall fast-path making it increasingly common for a thread to take an *_unavailable exception soon after a syscall, not to mention potentially taking all three. The obvious overcompensation to this problem is to simply always load all the facilities on every exit to userspace. Loading up all FPU, VEC and VSX registers every time can be expensive and if a workload does avoid using them, it should not be forced to incur this penalty. An 8bit counter is used to detect if the registers have been used in the past and the registers are always loaded until the value wraps to back to zero. Several versions of the assembly in entry_64.S were tested: 1. Always calling C. 2. Performing a common case check and then calling C. 3. A complex check in asm. After some benchmarking it was determined that avoiding C in the common case is a performance benefit (option 2). The full check in asm (option 3) greatly complicated that codepath for a negligible performance gain and the trade-off was deemed not worth it. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> [mpe: Move load_vec in the struct to fill an existing hole, reword change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> fixup
2016-02-29 14:53:47 +08:00
#ifdef CONFIG_PPC_BOOK3E
powerpc: Restore dbcr0 on user space exit On BookE (Branch taken + Single Step) is as same as Branch Taken on BookS and in Linux we simulate BookS behavior for BookE as well. When doing so, in Branch taken handling we want to set DBCR0_IC but we update the current->thread->dbcr0 and not DBCR0. Now on 64bit the current->thread.dbcr0 (and other debug registers) is synchronized ONLY on context switch flow. But after handling Branch taken in debug exception if we return back to user space without context switch then single stepping change (DBCR0_ICMP) does not get written in h/w DBCR0 and Instruction Complete exception does not happen. This fixes using ptrace reliably on BookE-PowerPC lmbench latency test (lat_syscall) Results are (they varies a little on each run) 1) ./lat_syscall <action> /dev/shm/uImage action: Open read write stat fstat null Before: 3.8618 0.2017 0.2851 1.6789 0.2256 0.0856 After: 3.8580 0.2017 0.2851 1.6955 0.2255 0.0856 1) ./lat_syscall -P 2 -N 10 <action> /dev/shm/uImage action: Open read write stat fstat null Before: 4.1388 0.2238 0.3066 1.7106 0.2256 0.0856 After: 4.1413 0.2236 0.3062 1.7107 0.2256 0.0856 [ Slightly modified to avoid extra branch in the fast path on Book3S and fix build on all non-BookE 64-bit -- BenH ] Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-22 12:20:59 +08:00
/*
* Check to see if the dbcr0 register is set up to debug.
* Use the internal debug mode bit to do this.
*/
andis. r0,r3,DBCR0_IDM@h
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
beq restore
powerpc: Restore dbcr0 on user space exit On BookE (Branch taken + Single Step) is as same as Branch Taken on BookS and in Linux we simulate BookS behavior for BookE as well. When doing so, in Branch taken handling we want to set DBCR0_IC but we update the current->thread->dbcr0 and not DBCR0. Now on 64bit the current->thread.dbcr0 (and other debug registers) is synchronized ONLY on context switch flow. But after handling Branch taken in debug exception if we return back to user space without context switch then single stepping change (DBCR0_ICMP) does not get written in h/w DBCR0 and Instruction Complete exception does not happen. This fixes using ptrace reliably on BookE-PowerPC lmbench latency test (lat_syscall) Results are (they varies a little on each run) 1) ./lat_syscall <action> /dev/shm/uImage action: Open read write stat fstat null Before: 3.8618 0.2017 0.2851 1.6789 0.2256 0.0856 After: 3.8580 0.2017 0.2851 1.6955 0.2255 0.0856 1) ./lat_syscall -P 2 -N 10 <action> /dev/shm/uImage action: Open read write stat fstat null Before: 4.1388 0.2238 0.3066 1.7106 0.2256 0.0856 After: 4.1413 0.2236 0.3062 1.7107 0.2256 0.0856 [ Slightly modified to avoid extra branch in the fast path on Book3S and fix build on all non-BookE 64-bit -- BenH ] Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-22 12:20:59 +08:00
mfmsr r0
rlwinm r0,r0,0,~MSR_DE /* Clear MSR.DE */
mtmsr r0
mtspr SPRN_DBCR0,r3
li r10, -1
mtspr SPRN_DBSR,r10
b restore
#else
powerpc: Restore FPU/VEC/VSX if previously used Currently the FPU, VEC and VSX facilities are lazily loaded. This is not a problem unless a process is using these facilities. Modern versions of GCC are very good at automatically vectorising code, new and modernised workloads make use of floating point and vector facilities, even the kernel makes use of vectorised memcpy. All this combined greatly increases the cost of a syscall since the kernel uses the facilities sometimes even in syscall fast-path making it increasingly common for a thread to take an *_unavailable exception soon after a syscall, not to mention potentially taking all three. The obvious overcompensation to this problem is to simply always load all the facilities on every exit to userspace. Loading up all FPU, VEC and VSX registers every time can be expensive and if a workload does avoid using them, it should not be forced to incur this penalty. An 8bit counter is used to detect if the registers have been used in the past and the registers are always loaded until the value wraps to back to zero. Several versions of the assembly in entry_64.S were tested: 1. Always calling C. 2. Performing a common case check and then calling C. 3. A complex check in asm. After some benchmarking it was determined that avoiding C in the common case is a performance benefit (option 2). The full check in asm (option 3) greatly complicated that codepath for a negligible performance gain and the trade-off was deemed not worth it. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> [mpe: Move load_vec in the struct to fill an existing hole, reword change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> fixup
2016-02-29 14:53:47 +08:00
addi r3,r1,STACK_FRAME_OVERHEAD
bl restore_math
b restore
powerpc: Restore dbcr0 on user space exit On BookE (Branch taken + Single Step) is as same as Branch Taken on BookS and in Linux we simulate BookS behavior for BookE as well. When doing so, in Branch taken handling we want to set DBCR0_IC but we update the current->thread->dbcr0 and not DBCR0. Now on 64bit the current->thread.dbcr0 (and other debug registers) is synchronized ONLY on context switch flow. But after handling Branch taken in debug exception if we return back to user space without context switch then single stepping change (DBCR0_ICMP) does not get written in h/w DBCR0 and Instruction Complete exception does not happen. This fixes using ptrace reliably on BookE-PowerPC lmbench latency test (lat_syscall) Results are (they varies a little on each run) 1) ./lat_syscall <action> /dev/shm/uImage action: Open read write stat fstat null Before: 3.8618 0.2017 0.2851 1.6789 0.2256 0.0856 After: 3.8580 0.2017 0.2851 1.6955 0.2255 0.0856 1) ./lat_syscall -P 2 -N 10 <action> /dev/shm/uImage action: Open read write stat fstat null Before: 4.1388 0.2238 0.3066 1.7106 0.2256 0.0856 After: 4.1413 0.2236 0.3062 1.7107 0.2256 0.0856 [ Slightly modified to avoid extra branch in the fast path on Book3S and fix build on all non-BookE 64-bit -- BenH ] Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-22 12:20:59 +08:00
#endif
1: andi. r0,r4,_TIF_NEED_RESCHED
beq 2f
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl restore_interrupts
powerpc: Use the new schedule_user API on userspace preemption This patch corresponds to [PATCH] x86: Use the new schedule_user API on userspace preemption commit 0430499ce9d78691f3985962021b16bf8f8a8048 Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-14 00:16:43 +08:00
SCHEDULE_USER
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
b ret_from_except_lite
powerpc: Don't corrupt transactional state when using FP/VMX in kernel Currently, when we have a process using the transactional memory facilities on POWER8 (that is, the processor is in transactional or suspended state), and the process enters the kernel and the kernel then uses the floating-point or vector (VMX/Altivec) facility, we end up corrupting the user-visible FP/VMX/VSX state. This happens, for example, if a page fault causes a copy-on-write operation, because the copy_page function will use VMX to do the copy on POWER8. The test program below demonstrates the bug. The bug happens because when FP/VMX state for a transactional process is stored in the thread_struct, we store the checkpointed state in .fp_state/.vr_state and the transactional (current) state in .transact_fp/.transact_vr. However, when the kernel wants to use FP/VMX, it calls enable_kernel_fp() or enable_kernel_altivec(), which saves the current state in .fp_state/.vr_state. Furthermore, when we return to the user process we return with FP/VMX/VSX disabled. The next time the process uses FP/VMX/VSX, we don't know which set of state (the current register values, .fp_state/.vr_state, or .transact_fp/.transact_vr) we should be using, since we have no way to tell if we are still in the same transaction, and if not, whether the previous transaction succeeded or failed. Thus it is necessary to strictly adhere to the rule that if FP has been enabled at any point in a transaction, we must keep FP enabled for the user process with the current transactional state in the FP registers, until we detect that it is no longer in a transaction. Similarly for VMX; once enabled it must stay enabled until the process is no longer transactional. In order to keep this rule, we add a new thread_info flag which we test when returning from the kernel to userspace, called TIF_RESTORE_TM. This flag indicates that there is FP/VMX/VSX state to be restored before entering userspace, and when it is set the .tm_orig_msr field in the thread_struct indicates what state needs to be restored. The restoration is done by restore_tm_state(). The TIF_RESTORE_TM bit is set by new giveup_fpu/altivec_maybe_transactional helpers, which are called from enable_kernel_fp/altivec, giveup_vsx, and flush_fp/altivec_to_thread instead of giveup_fpu/altivec. The other thing to be done is to get the transactional FP/VMX/VSX state from .fp_state/.vr_state when doing reclaim, if that state has been saved there by giveup_fpu/altivec_maybe_transactional. Having done this, we set the FP/VMX bit in the thread's MSR after reclaim to indicate that that part of the state is now valid (having been reclaimed from the processor's checkpointed state). Finally, in the signal handling code, we move the clearing of the transactional state bits in the thread's MSR a bit earlier, before calling flush_fp_to_thread(), so that we don't unnecessarily set the TIF_RESTORE_TM bit. This is the test program: /* Michael Neuling 4/12/2013 * * See if the altivec state is leaked out of an aborted transaction due to * kernel vmx copy loops. * * gcc -m64 htm_vmxcopy.c -o htm_vmxcopy * */ /* We don't use all of these, but for reference: */ int main(int argc, char *argv[]) { long double vecin = 1.3; long double vecout; unsigned long pgsize = getpagesize(); int i; int fd; int size = pgsize*16; char tmpfile[] = "/tmp/page_faultXXXXXX"; char buf[pgsize]; char *a; uint64_t aborted = 0; fd = mkstemp(tmpfile); assert(fd >= 0); memset(buf, 0, pgsize); for (i = 0; i < size; i += pgsize) assert(write(fd, buf, pgsize) == pgsize); unlink(tmpfile); a = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); assert(a != MAP_FAILED); asm __volatile__( "lxvd2x 40,0,%[vecinptr] ; " // set 40 to initial value TBEGIN "beq 3f ;" TSUSPEND "xxlxor 40,40,40 ; " // set 40 to 0 "std 5, 0(%[map]) ;" // cause kernel vmx copy page TABORT TRESUME TEND "li %[res], 0 ;" "b 5f ;" "3: ;" // Abort handler "li %[res], 1 ;" "5: ;" "stxvd2x 40,0,%[vecoutptr] ; " : [res]"=r"(aborted) : [vecinptr]"r"(&vecin), [vecoutptr]"r"(&vecout), [map]"r"(a) : "memory", "r0", "r3", "r4", "r5", "r6", "r7"); if (aborted && (vecin != vecout)){ printf("FAILED: vector state leaked on abort %f != %f\n", (double)vecin, (double)vecout); exit(1); } munmap(a, size); close(fd); printf("PASSED!\n"); return 0; } Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-01-13 12:56:29 +08:00
2:
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
andi. r0,r4,_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM
bne 3f /* only restore TM if nothing else to do */
addi r3,r1,STACK_FRAME_OVERHEAD
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl restore_tm_state
powerpc: Don't corrupt transactional state when using FP/VMX in kernel Currently, when we have a process using the transactional memory facilities on POWER8 (that is, the processor is in transactional or suspended state), and the process enters the kernel and the kernel then uses the floating-point or vector (VMX/Altivec) facility, we end up corrupting the user-visible FP/VMX/VSX state. This happens, for example, if a page fault causes a copy-on-write operation, because the copy_page function will use VMX to do the copy on POWER8. The test program below demonstrates the bug. The bug happens because when FP/VMX state for a transactional process is stored in the thread_struct, we store the checkpointed state in .fp_state/.vr_state and the transactional (current) state in .transact_fp/.transact_vr. However, when the kernel wants to use FP/VMX, it calls enable_kernel_fp() or enable_kernel_altivec(), which saves the current state in .fp_state/.vr_state. Furthermore, when we return to the user process we return with FP/VMX/VSX disabled. The next time the process uses FP/VMX/VSX, we don't know which set of state (the current register values, .fp_state/.vr_state, or .transact_fp/.transact_vr) we should be using, since we have no way to tell if we are still in the same transaction, and if not, whether the previous transaction succeeded or failed. Thus it is necessary to strictly adhere to the rule that if FP has been enabled at any point in a transaction, we must keep FP enabled for the user process with the current transactional state in the FP registers, until we detect that it is no longer in a transaction. Similarly for VMX; once enabled it must stay enabled until the process is no longer transactional. In order to keep this rule, we add a new thread_info flag which we test when returning from the kernel to userspace, called TIF_RESTORE_TM. This flag indicates that there is FP/VMX/VSX state to be restored before entering userspace, and when it is set the .tm_orig_msr field in the thread_struct indicates what state needs to be restored. The restoration is done by restore_tm_state(). The TIF_RESTORE_TM bit is set by new giveup_fpu/altivec_maybe_transactional helpers, which are called from enable_kernel_fp/altivec, giveup_vsx, and flush_fp/altivec_to_thread instead of giveup_fpu/altivec. The other thing to be done is to get the transactional FP/VMX/VSX state from .fp_state/.vr_state when doing reclaim, if that state has been saved there by giveup_fpu/altivec_maybe_transactional. Having done this, we set the FP/VMX bit in the thread's MSR after reclaim to indicate that that part of the state is now valid (having been reclaimed from the processor's checkpointed state). Finally, in the signal handling code, we move the clearing of the transactional state bits in the thread's MSR a bit earlier, before calling flush_fp_to_thread(), so that we don't unnecessarily set the TIF_RESTORE_TM bit. This is the test program: /* Michael Neuling 4/12/2013 * * See if the altivec state is leaked out of an aborted transaction due to * kernel vmx copy loops. * * gcc -m64 htm_vmxcopy.c -o htm_vmxcopy * */ /* We don't use all of these, but for reference: */ int main(int argc, char *argv[]) { long double vecin = 1.3; long double vecout; unsigned long pgsize = getpagesize(); int i; int fd; int size = pgsize*16; char tmpfile[] = "/tmp/page_faultXXXXXX"; char buf[pgsize]; char *a; uint64_t aborted = 0; fd = mkstemp(tmpfile); assert(fd >= 0); memset(buf, 0, pgsize); for (i = 0; i < size; i += pgsize) assert(write(fd, buf, pgsize) == pgsize); unlink(tmpfile); a = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); assert(a != MAP_FAILED); asm __volatile__( "lxvd2x 40,0,%[vecinptr] ; " // set 40 to initial value TBEGIN "beq 3f ;" TSUSPEND "xxlxor 40,40,40 ; " // set 40 to 0 "std 5, 0(%[map]) ;" // cause kernel vmx copy page TABORT TRESUME TEND "li %[res], 0 ;" "b 5f ;" "3: ;" // Abort handler "li %[res], 1 ;" "5: ;" "stxvd2x 40,0,%[vecoutptr] ; " : [res]"=r"(aborted) : [vecinptr]"r"(&vecin), [vecoutptr]"r"(&vecout), [map]"r"(a) : "memory", "r0", "r3", "r4", "r5", "r6", "r7"); if (aborted && (vecin != vecout)){ printf("FAILED: vector state leaked on abort %f != %f\n", (double)vecin, (double)vecout); exit(1); } munmap(a, size); close(fd); printf("PASSED!\n"); return 0; } Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-01-13 12:56:29 +08:00
b restore
3:
#endif
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl save_nvgprs
powerpc: do_notify_resume can be called with bad thread_info flags argument Back in 7230c5644188 ("powerpc: Rework lazy-interrupt handling") we added a call out to restore_interrupts() (written in c) before calling do_notify_resume: bl restore_interrupts addi r3,r1,STACK_FRAME_OVERHEAD bl do_notify_resume Unfortunately do_notify_resume takes two arguments, the second one being the thread_info flags: void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) We do populate r4 (the second argument) earlier, but restore_interrupts() is free to muck it up all it wants. My guess is the gcc compiler gods shone down on us and its register allocator never used r4. Sometimes, rarely, luck is on our side. LLVM on the other hand did trample r4. Signed-off-by: Anton Blanchard <anton@samba.org> Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-31 13:50:57 +08:00
/*
* Use a non volatile GPR to save and restore our thread_info flags
* across the call to restore_interrupts.
*/
mr r30,r4
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl restore_interrupts
powerpc: do_notify_resume can be called with bad thread_info flags argument Back in 7230c5644188 ("powerpc: Rework lazy-interrupt handling") we added a call out to restore_interrupts() (written in c) before calling do_notify_resume: bl restore_interrupts addi r3,r1,STACK_FRAME_OVERHEAD bl do_notify_resume Unfortunately do_notify_resume takes two arguments, the second one being the thread_info flags: void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) We do populate r4 (the second argument) earlier, but restore_interrupts() is free to muck it up all it wants. My guess is the gcc compiler gods shone down on us and its register allocator never used r4. Sometimes, rarely, luck is on our side. LLVM on the other hand did trample r4. Signed-off-by: Anton Blanchard <anton@samba.org> Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-31 13:50:57 +08:00
mr r4,r30
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
addi r3,r1,STACK_FRAME_OVERHEAD
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl do_notify_resume
b ret_from_except
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
resume_kernel:
powerpc/kprobe: Complete kprobe and migrate exception frame We can't emulate stwu since that may corrupt current exception stack. So we will have to do real store operation in the exception return code. Firstly we'll allocate a trampoline exception frame below the kprobed function stack and copy the current exception frame to the trampoline. Then we can do this real store operation to implement 'stwu', and reroute the trampoline frame to r1 to complete this exception migration. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-17 07:54:30 +08:00
/* check current_thread_info, _TIF_EMULATE_STACK_STORE */
powerpc/ppc64: Remove the unneeded load of ti_flags in resume_kernel We already got the value of current_thread_info and ti_flags and store them into r9 and r4 respectively before jumping to resume_kernel. So there is no reason to reload them again. Signed-off-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-26 16:41:34 +08:00
andis. r8,r4,_TIF_EMULATE_STACK_STORE@h
powerpc/kprobe: Complete kprobe and migrate exception frame We can't emulate stwu since that may corrupt current exception stack. So we will have to do real store operation in the exception return code. Firstly we'll allocate a trampoline exception frame below the kprobed function stack and copy the current exception frame to the trampoline. Then we can do this real store operation to implement 'stwu', and reroute the trampoline frame to r1 to complete this exception migration. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-17 07:54:30 +08:00
beq+ 1f
addi r8,r1,INT_FRAME_SIZE /* Get the kprobed function entry */
powerpc/kprobe: Fix oops when kprobed on 'stdu' instruction If we set a kprobe on a 'stdu' instruction on powerpc64, we see a kernel OOPS: Bad kernel stack pointer cd93c840 at c000000000009868 Oops: Bad kernel stack pointer, sig: 6 [#1] ... GPR00: c000001fcd93cb30 00000000cd93c840 c0000000015c5e00 00000000cd93c840 ... NIP [c000000000009868] resume_kernel+0x2c/0x58 LR [c000000000006208] program_check_common+0x108/0x180 On a 64-bit system when the user probes on a 'stdu' instruction, the kernel does not emulate actual store in emulate_step() because it may corrupt the exception frame. So the kernel does the actual store operation in exception return code i.e. resume_kernel(). resume_kernel() loads the saved stack pointer from memory using lwz, which only loads the low 32-bits of the address, causing the kernel crash. Fix this by loading the 64-bit value instead. Fixes: be96f63375a1 ("powerpc: Split out instruction analysis part of emulate_step()") Cc: stable@vger.kernel.org # v3.18+ Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> [mpe: Change log massage, add stable tag] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-11 13:08:13 +08:00
ld r3,GPR1(r1)
powerpc/kprobe: Complete kprobe and migrate exception frame We can't emulate stwu since that may corrupt current exception stack. So we will have to do real store operation in the exception return code. Firstly we'll allocate a trampoline exception frame below the kprobed function stack and copy the current exception frame to the trampoline. Then we can do this real store operation to implement 'stwu', and reroute the trampoline frame to r1 to complete this exception migration. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-17 07:54:30 +08:00
subi r3,r3,INT_FRAME_SIZE /* dst: Allocate a trampoline exception frame */
mr r4,r1 /* src: current exception frame */
mr r1,r3 /* Reroute the trampoline frame to r1 */
/* Copy from the original to the trampoline. */
li r5,INT_FRAME_SIZE/8 /* size: INT_FRAME_SIZE */
li r6,0 /* start offset: 0 */
mtctr r5
2: ldx r0,r6,r4
stdx r0,r6,r3
addi r6,r6,8
bdnz 2b
powerpc/kprobe: Fix oops when kprobed on 'stdu' instruction If we set a kprobe on a 'stdu' instruction on powerpc64, we see a kernel OOPS: Bad kernel stack pointer cd93c840 at c000000000009868 Oops: Bad kernel stack pointer, sig: 6 [#1] ... GPR00: c000001fcd93cb30 00000000cd93c840 c0000000015c5e00 00000000cd93c840 ... NIP [c000000000009868] resume_kernel+0x2c/0x58 LR [c000000000006208] program_check_common+0x108/0x180 On a 64-bit system when the user probes on a 'stdu' instruction, the kernel does not emulate actual store in emulate_step() because it may corrupt the exception frame. So the kernel does the actual store operation in exception return code i.e. resume_kernel(). resume_kernel() loads the saved stack pointer from memory using lwz, which only loads the low 32-bits of the address, causing the kernel crash. Fix this by loading the 64-bit value instead. Fixes: be96f63375a1 ("powerpc: Split out instruction analysis part of emulate_step()") Cc: stable@vger.kernel.org # v3.18+ Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> [mpe: Change log massage, add stable tag] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-11 13:08:13 +08:00
/* Do real store operation to complete stdu */
ld r5,GPR1(r1)
powerpc/kprobe: Complete kprobe and migrate exception frame We can't emulate stwu since that may corrupt current exception stack. So we will have to do real store operation in the exception return code. Firstly we'll allocate a trampoline exception frame below the kprobed function stack and copy the current exception frame to the trampoline. Then we can do this real store operation to implement 'stwu', and reroute the trampoline frame to r1 to complete this exception migration. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-17 07:54:30 +08:00
std r8,0(r5)
/* Clear _TIF_EMULATE_STACK_STORE flag */
lis r11,_TIF_EMULATE_STACK_STORE@h
addi r5,r9,TI_FLAGS
powerpc: add a missing label in resume_kernel A label 0 was missed in the patch a9c4e541 (powerpc/kprobe: Complete kprobe and migrate exception frame). This will cause the kernel branch to an undetermined address if there really has a conflict when updating the thread flags. Signed-off-by: Kevin Hao <haokexin@gmail.com> Cc: stable@vger.kernel.org Acked-By: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
2013-04-10 06:31:24 +08:00
0: ldarx r4,0,r5
powerpc/kprobe: Complete kprobe and migrate exception frame We can't emulate stwu since that may corrupt current exception stack. So we will have to do real store operation in the exception return code. Firstly we'll allocate a trampoline exception frame below the kprobed function stack and copy the current exception frame to the trampoline. Then we can do this real store operation to implement 'stwu', and reroute the trampoline frame to r1 to complete this exception migration. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-17 07:54:30 +08:00
andc r4,r4,r11
stdcx. r4,0,r5
bne- 0b
1:
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
#ifdef CONFIG_PREEMPT
/* Check if we need to preempt */
andi. r0,r4,_TIF_NEED_RESCHED
beq+ restore
/* Check that preempt_count() == 0 and interrupts are enabled */
lwz r8,TI_PREEMPT(r9)
cmpwi cr1,r8,0
ld r0,SOFTE(r1)
cmpdi r0,0
crandc eq,cr1*4+eq,eq
bne restore
/*
* Here we are preempting the current task. We want to make
powerpc/ppc64: Rename SOFT_DISABLE_INTS with RECONCILE_IRQ_STATE The SOFT_DISABLE_INTS seems an odd name for something that updates the software state to be consistent with interrupts being hard disabled, so rename SOFT_DISABLE_INTS with RECONCILE_IRQ_STATE to avoid this confusion. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-07-16 11:09:30 +08:00
* sure we are soft-disabled first and reconcile irq state.
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
*/
powerpc/ppc64: Rename SOFT_DISABLE_INTS with RECONCILE_IRQ_STATE The SOFT_DISABLE_INTS seems an odd name for something that updates the software state to be consistent with interrupts being hard disabled, so rename SOFT_DISABLE_INTS with RECONCILE_IRQ_STATE to avoid this confusion. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-07-16 11:09:30 +08:00
RECONCILE_IRQ_STATE(r3,r4)
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
1: bl preempt_schedule_irq
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
/* Re-test flags and eventually loop */
powerpc: Use CURRENT_THREAD_INFO instead of open coded assembly Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-05 12:41:35 +08:00
CURRENT_THREAD_INFO(r9, r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r4,TI_FLAGS(r9)
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
andi. r0,r4,_TIF_NEED_RESCHED
bne 1b
powerpc/book3e: Disable interrupt after preempt_schedule_irq In preempt case current arch_local_irq_restore() from preempt_schedule_irq() may enable hard interrupt but we really should disable interrupts when we return from the interrupt, and so that we don't get interrupted after loading SRR0/1. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> CC: <stable@vger.kernel.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-01-06 08:49:34 +08:00
/*
* arch_local_irq_restore() from preempt_schedule_irq above may
* enable hard interrupt but we really should disable interrupts
* when we return from the interrupt, and so that we don't get
* interrupted after loading SRR0/1.
*/
#ifdef CONFIG_PPC_BOOK3E
wrteei 0
#else
powerpc/64s: Optimise MSR handling in exception handling mtmsrd with L=1 only affects MSR_EE and MSR_RI bits, and we always know what state those bits are, so the kernel MSR does not need to be loaded when modifying them. mtmsrd is often in the critical execution path, so avoiding dependency on even L1 load is noticable. On a POWER8 this saves about 3 cycles from the syscall path, and possibly a few from other exception returns (not measured). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-15 17:04:46 +08:00
li r10,MSR_RI
powerpc/book3e: Disable interrupt after preempt_schedule_irq In preempt case current arch_local_irq_restore() from preempt_schedule_irq() may enable hard interrupt but we really should disable interrupts when we return from the interrupt, and so that we don't get interrupted after loading SRR0/1. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> CC: <stable@vger.kernel.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-01-06 08:49:34 +08:00
mtmsrd r10,1 /* Update machine state */
#endif /* CONFIG_PPC_BOOK3E */
ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt In entry_64.S version of ret_from_except_lite, you'll notice that in the !preempt case, after we've checked MSR_PR we test for any TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work or not. However, in the preempt case, we do a convoluted trick to test SIGPENDING only if PR was set and always test NEED_RESCHED ... but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So that means that with preempt, we completely fail to test for things like single step, syscall tracing, etc... This should be fixed as the following path: - Test PR. If not set, go to resume_kernel, else continue. - If go resume_kernel, to do that original do_work. - If else, then always test for _TIF_USER_WORK_MASK to decide to do that original user_work, else restore directly. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-07 04:56:43 +08:00
#endif /* CONFIG_PREEMPT */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
.globl fast_exc_return_irq
fast_exc_return_irq:
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
restore:
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
/*
powerpc/irq: Fix another case of lazy IRQ state getting out of sync So we have another case of paca->irq_happened getting out of sync with the HW irq state. This can happen when a perfmon interrupt occurs while soft disabled, as it will return to a soft disabled but hard enabled context while leaving a stale PACA_IRQ_HARD_DIS flag set. This patch fixes it, and also adds a test for the condition of those flags being out of sync in arch_local_irq_restore() when CONFIG_TRACE_IRQFLAGS is enabled. This helps catching those gremlins faster (and so far I can't seem see any anymore, so that's good news). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-11 00:12:38 +08:00
* This is the main kernel exit path. First we check if we
* are about to re-enable interrupts
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
*/
powerpc: Streamline ret_from_except_lite for non-iSeries platforms There is a small passage of code in ret_from_except_lite which is only required on iSeries. For a multi-platform kernel on non-iSeries machines this means we end up executing ~15 nops in ret_from_except_lite. It would be nicer if non-iSeries could skip the code entirely, and on iSeries we can jump out of line to execute the code. I have no performance numbers to justify this, other than the assertion that executing 15 nops takes longer than executing 0. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-16 12:21:34 +08:00
ld r5,SOFTE(r1)
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
lbz r6,PACASOFTIRQEN(r13)
powerpc/irq: Fix another case of lazy IRQ state getting out of sync So we have another case of paca->irq_happened getting out of sync with the HW irq state. This can happen when a perfmon interrupt occurs while soft disabled, as it will return to a soft disabled but hard enabled context while leaving a stale PACA_IRQ_HARD_DIS flag set. This patch fixes it, and also adds a test for the condition of those flags being out of sync in arch_local_irq_restore() when CONFIG_TRACE_IRQFLAGS is enabled. This helps catching those gremlins faster (and so far I can't seem see any anymore, so that's good news). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-11 00:12:38 +08:00
cmpwi cr0,r5,0
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
beq .Lrestore_irq_off
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
powerpc/irq: Fix another case of lazy IRQ state getting out of sync So we have another case of paca->irq_happened getting out of sync with the HW irq state. This can happen when a perfmon interrupt occurs while soft disabled, as it will return to a soft disabled but hard enabled context while leaving a stale PACA_IRQ_HARD_DIS flag set. This patch fixes it, and also adds a test for the condition of those flags being out of sync in arch_local_irq_restore() when CONFIG_TRACE_IRQFLAGS is enabled. This helps catching those gremlins faster (and so far I can't seem see any anymore, so that's good news). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-11 00:12:38 +08:00
/* We are enabling, were we already enabled ? Yes, just return */
cmpwi cr0,r6,1
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
beq cr0,.Ldo_restore
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc/irq: Fix another case of lazy IRQ state getting out of sync So we have another case of paca->irq_happened getting out of sync with the HW irq state. This can happen when a perfmon interrupt occurs while soft disabled, as it will return to a soft disabled but hard enabled context while leaving a stale PACA_IRQ_HARD_DIS flag set. This patch fixes it, and also adds a test for the condition of those flags being out of sync in arch_local_irq_restore() when CONFIG_TRACE_IRQFLAGS is enabled. This helps catching those gremlins faster (and so far I can't seem see any anymore, so that's good news). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-11 00:12:38 +08:00
/*
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
* We are about to soft-enable interrupts (we are hard disabled
* at this point). We check if there's anything that needs to
* be replayed first.
*/
lbz r0,PACAIRQHAPPENED(r13)
cmpwi cr0,r0,0
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
bne- .Lrestore_check_irq_replay
[POWERPC] Clear RI bit in MSR before restoring r13 when returning to userspace Some instruction tracing tools use the RI (recoverable interrupt) bit in the MSR to indicate when it's safe to single-step. Currently we clear RI after restoring r13 when returning to userspace. However, if we single-step past the point where r13 is restored, we'll corrupt r13 in the exception entry code and not restore it. This moves the clearing of RI to just before r13 is restored so this doesn't happen. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07 10:13:26 +08:00
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
/*
* Get here when nothing happened while soft-disabled, just
* soft-enable and move-on. We will hard-enable as a side
* effect of rfi
*/
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
.Lrestore_no_replay:
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
TRACE_ENABLE_INTS
li r0,1
stb r0,PACASOFTIRQEN(r13);
/*
* Final return path. BookE is handled in a different file
*/
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
.Ldo_restore:
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#ifdef CONFIG_PPC_BOOK3E
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
b exception_return_book3e
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#else
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
/*
* Clear the reservation. If we know the CPU tracks the address of
* the reservation then we can potentially save some cycles and use
* a larx. On POWER6 and POWER7 this is significantly faster.
*/
BEGIN_FTR_SECTION
stdcx. r0,0,r1 /* to clear the reservation */
FTR_SECTION_ELSE
ldarx r4,0,r1
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
/*
* Some code path such as load_up_fpu or altivec return directly
* here. They run entirely hard disabled and do not alter the
* interrupt state. They also don't use lwarx/stwcx. and thus
* are known not to leave dangling reservations.
*/
.globl fast_exception_return
fast_exception_return:
ld r3,_MSR(r1)
[POWERPC] Clear RI bit in MSR before restoring r13 when returning to userspace Some instruction tracing tools use the RI (recoverable interrupt) bit in the MSR to indicate when it's safe to single-step. Currently we clear RI after restoring r13 when returning to userspace. However, if we single-step past the point where r13 is restored, we'll corrupt r13 in the exception entry code and not restore it. This moves the clearing of RI to just before r13 is restored so this doesn't happen. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07 10:13:26 +08:00
ld r4,_CTR(r1)
ld r0,_LINK(r1)
mtctr r4
mtlr r0
ld r4,_XER(r1)
mtspr SPRN_XER,r4
REST_8GPRS(5, r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
andi. r0,r3,MSR_RI
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
beq- .Lunrecov_restore
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: Fix fatal SLB miss when restoring PPR When restoring the PPR value, we incorrectly access the thread structure at a time where MSR:RI is clear, which means we cannot recover from nested faults. However the thread structure isn't covered by the "bolted" SLB entries and thus accessing can fault. This fixes it by splitting the code so that the PPR value is loaded into a GPR before MSR:RI is cleared. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-11-05 13:33:22 +08:00
/* Load PPR from thread struct before we clear MSR:RI */
BEGIN_FTR_SECTION
ld r2,PACACURRENT(r13)
ld r2,TASKTHREADPPR(r2)
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
[POWERPC] Clear RI bit in MSR before restoring r13 when returning to userspace Some instruction tracing tools use the RI (recoverable interrupt) bit in the MSR to indicate when it's safe to single-step. Currently we clear RI after restoring r13 when returning to userspace. However, if we single-step past the point where r13 is restored, we'll corrupt r13 in the exception entry code and not restore it. This moves the clearing of RI to just before r13 is restored so this doesn't happen. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07 10:13:26 +08:00
/*
* Clear RI before restoring r13. If we are returning to
* userspace and we take an exception after restoring r13,
* we end up corrupting the userspace r13 value.
*/
powerpc/64s: Optimise MSR handling in exception handling mtmsrd with L=1 only affects MSR_EE and MSR_RI bits, and we always know what state those bits are, so the kernel MSR does not need to be loaded when modifying them. mtmsrd is often in the critical execution path, so avoiding dependency on even L1 load is noticable. On a POWER8 this saves about 3 cycles from the syscall path, and possibly a few from other exception returns (not measured). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-15 17:04:46 +08:00
li r4,0
[POWERPC] Clear RI bit in MSR before restoring r13 when returning to userspace Some instruction tracing tools use the RI (recoverable interrupt) bit in the MSR to indicate when it's safe to single-step. Currently we clear RI after restoring r13 when returning to userspace. However, if we single-step past the point where r13 is restored, we'll corrupt r13 in the exception entry code and not restore it. This moves the clearing of RI to just before r13 is restored so this doesn't happen. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07 10:13:26 +08:00
mtmsrd r4,1
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: Add transactional memory paca scratch register to show_regs Add transactional memory paca scratch register to show_regs. This is useful for debugging. Signed-off-by: Matt Evans <matt@ozlabs.org> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-02-14 00:21:34 +08:00
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/* TM debug */
std r3, PACATMSCRATCH(r13) /* Stash returned-to MSR */
#endif
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/*
* r13 is our per cpu area, only restore it if we are returning to
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
* userspace the value stored in the stack frame may belong to
* another CPU.
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
*/
[POWERPC] Clear RI bit in MSR before restoring r13 when returning to userspace Some instruction tracing tools use the RI (recoverable interrupt) bit in the MSR to indicate when it's safe to single-step. Currently we clear RI after restoring r13 when returning to userspace. However, if we single-step past the point where r13 is restored, we'll corrupt r13 in the exception entry code and not restore it. This moves the clearing of RI to just before r13 is restored so this doesn't happen. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07 10:13:26 +08:00
andi. r0,r3,MSR_PR
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
beq 1f
powerpc: Fix fatal SLB miss when restoring PPR When restoring the PPR value, we incorrectly access the thread structure at a time where MSR:RI is clear, which means we cannot recover from nested faults. However the thread structure isn't covered by the "bolted" SLB entries and thus accessing can fault. This fixes it by splitting the code so that the PPR value is loaded into a GPR before MSR:RI is cleared. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-11-05 13:33:22 +08:00
BEGIN_FTR_SECTION
mtspr SPRN_PPR,r2 /* Restore PPR */
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
powerpc32: provide VIRT_CPU_ACCOUNTING This patch provides VIRT_CPU_ACCOUTING to PPC32 architecture. PPC32 doesn't have the PACA structure, so we use the task_info structure to store the accounting data. In order to reuse on PPC32 the PPC64 functions, all u64 data has been replaced by 'unsigned long' so that it is u32 on PPC32 and u64 on PPC64 Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Scott Wood <oss@buserror.net>
2016-05-17 14:33:46 +08:00
ACCOUNT_CPU_USER_EXIT(r13, r2, r4)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
REST_GPR(13, r1)
1:
[POWERPC] Clear RI bit in MSR before restoring r13 when returning to userspace Some instruction tracing tools use the RI (recoverable interrupt) bit in the MSR to indicate when it's safe to single-step. Currently we clear RI after restoring r13 when returning to userspace. However, if we single-step past the point where r13 is restored, we'll corrupt r13 in the exception entry code and not restore it. This moves the clearing of RI to just before r13 is restored so this doesn't happen. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-02-07 10:13:26 +08:00
mtspr SPRN_SRR1,r3
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r2,_CCR(r1)
mtcrf 0xFF,r2
ld r2,_NIP(r1)
mtspr SPRN_SRR0,r2
ld r0,GPR0(r1)
ld r2,GPR2(r1)
ld r3,GPR3(r1)
ld r4,GPR4(r1)
ld r1,GPR1(r1)
rfid
b . /* prevent speculative execution */
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#endif /* CONFIG_PPC_BOOK3E */
powerpc/irq: Fix another case of lazy IRQ state getting out of sync So we have another case of paca->irq_happened getting out of sync with the HW irq state. This can happen when a perfmon interrupt occurs while soft disabled, as it will return to a soft disabled but hard enabled context while leaving a stale PACA_IRQ_HARD_DIS flag set. This patch fixes it, and also adds a test for the condition of those flags being out of sync in arch_local_irq_restore() when CONFIG_TRACE_IRQFLAGS is enabled. This helps catching those gremlins faster (and so far I can't seem see any anymore, so that's good news). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-11 00:12:38 +08:00
/*
* We are returning to a context with interrupts soft disabled.
*
* However, we may also about to hard enable, so we need to
* make sure that in this case, we also clear PACA_IRQ_HARD_DIS
* or that bit can get out of sync and bad things will happen
*/
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
.Lrestore_irq_off:
powerpc/irq: Fix another case of lazy IRQ state getting out of sync So we have another case of paca->irq_happened getting out of sync with the HW irq state. This can happen when a perfmon interrupt occurs while soft disabled, as it will return to a soft disabled but hard enabled context while leaving a stale PACA_IRQ_HARD_DIS flag set. This patch fixes it, and also adds a test for the condition of those flags being out of sync in arch_local_irq_restore() when CONFIG_TRACE_IRQFLAGS is enabled. This helps catching those gremlins faster (and so far I can't seem see any anymore, so that's good news). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-11 00:12:38 +08:00
ld r3,_MSR(r1)
lbz r7,PACAIRQHAPPENED(r13)
andi. r0,r3,MSR_EE
beq 1f
rlwinm r7,r7,0,~PACA_IRQ_HARD_DIS
stb r7,PACAIRQHAPPENED(r13)
1: li r0,0
stb r0,PACASOFTIRQEN(r13);
TRACE_DISABLE_INTS
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
b .Ldo_restore
powerpc/irq: Fix another case of lazy IRQ state getting out of sync So we have another case of paca->irq_happened getting out of sync with the HW irq state. This can happen when a perfmon interrupt occurs while soft disabled, as it will return to a soft disabled but hard enabled context while leaving a stale PACA_IRQ_HARD_DIS flag set. This patch fixes it, and also adds a test for the condition of those flags being out of sync in arch_local_irq_restore() when CONFIG_TRACE_IRQFLAGS is enabled. This helps catching those gremlins faster (and so far I can't seem see any anymore, so that's good news). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-05-11 00:12:38 +08:00
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
/*
* Something did happen, check if a re-emit is needed
* (this also clears paca->irq_happened)
*/
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
.Lrestore_check_irq_replay:
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
/* XXX: We could implement a fast path here where we check
* for irq_happened being just 0x01, in which case we can
* clear it and return. That means that we would potentially
* miss a decrementer having wrapped all the way around.
*
* Still, this might be useful for things like hash_page
*/
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl __check_irq_replay
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
cmpwi cr0,r3,0
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
beq .Lrestore_no_replay
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
/*
* We need to re-emit an interrupt. We do so by re-using our
* existing exception frame. We first change the trap value,
* but we need to ensure we preserve the low nibble of it
*/
ld r4,_TRAP(r1)
clrldi r4,r4,60
or r4,r4,r3
std r4,_TRAP(r1)
/*
* Then find the right handler and call it. Interrupts are
* still soft-disabled and we keep them that way.
*/
cmpwi cr0,r3,0x500
bne 1f
addi r3,r1,STACK_FRAME_OVERHEAD;
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl do_IRQ
b ret_from_except
powerpc/book3s: Add basic infrastructure to handle HMI in Linux. Handle Hypervisor Maintenance Interrupt (HMI) in Linux. This patch implements basic infrastructure to handle HMI in Linux host. The design is to invoke opal handle hmi in real mode for recovery and set irq_pending when we hit HMI. During check_irq_replay pull opal hmi event and print hmi info on console. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-29 21:10:01 +08:00
1: cmpwi cr0,r3,0xe60
bne 1f
addi r3,r1,STACK_FRAME_OVERHEAD;
bl handle_hmi_exception
b ret_from_except
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
1: cmpwi cr0,r3,0x900
bne 1f
addi r3,r1,STACK_FRAME_OVERHEAD;
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl timer_interrupt
b ret_from_except
powerpc: Add code to handle soft-disabled doorbells on server This patch adds the logic to properly handle doorbells that come in when interrupts have been soft disabled and to replay them when interrupts are re-enabled: - masked_##_H##interrupt is modified to leave interrupts enabled when a doorbell has come in since doorbells are edge sensitive and as such won't be automatically re-raised. - __check_irq_replay now tests if a doorbell happened on book3s, and returns either 0xe80 or 0xa00 depending on whether we are the hypervisor or not. - restore_check_irq_replay now tests for the two possible server doorbell vector numbers to replay. - __replay_interrupt also adds tests for the two server doorbell vector numbers, and is modified to use a compare instruction rather than an andi. on the single bit difference between 0x500 and 0x900. The last two use a CPU feature section to avoid needlessly testing against the hypervisor vector if it is not the hypervisor, and vice versa. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-11-15 02:49:48 +08:00
#ifdef CONFIG_PPC_DOORBELL
1:
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
#ifdef CONFIG_PPC_BOOK3E
powerpc: Add code to handle soft-disabled doorbells on server This patch adds the logic to properly handle doorbells that come in when interrupts have been soft disabled and to replay them when interrupts are re-enabled: - masked_##_H##interrupt is modified to leave interrupts enabled when a doorbell has come in since doorbells are edge sensitive and as such won't be automatically re-raised. - __check_irq_replay now tests if a doorbell happened on book3s, and returns either 0xe80 or 0xa00 depending on whether we are the hypervisor or not. - restore_check_irq_replay now tests for the two possible server doorbell vector numbers to replay. - __replay_interrupt also adds tests for the two server doorbell vector numbers, and is modified to use a compare instruction rather than an andi. on the single bit difference between 0x500 and 0x900. The last two use a CPU feature section to avoid needlessly testing against the hypervisor vector if it is not the hypervisor, and vice versa. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-11-15 02:49:48 +08:00
cmpwi cr0,r3,0x280
#else
BEGIN_FTR_SECTION
cmpwi cr0,r3,0xe80
FTR_SECTION_ELSE
cmpwi cr0,r3,0xa00
ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
#endif /* CONFIG_PPC_BOOK3E */
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
bne 1f
addi r3,r1,STACK_FRAME_OVERHEAD;
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl doorbell_exception
b ret_from_except
powerpc: Add code to handle soft-disabled doorbells on server This patch adds the logic to properly handle doorbells that come in when interrupts have been soft disabled and to replay them when interrupts are re-enabled: - masked_##_H##interrupt is modified to leave interrupts enabled when a doorbell has come in since doorbells are edge sensitive and as such won't be automatically re-raised. - __check_irq_replay now tests if a doorbell happened on book3s, and returns either 0xe80 or 0xa00 depending on whether we are the hypervisor or not. - restore_check_irq_replay now tests for the two possible server doorbell vector numbers to replay. - __replay_interrupt also adds tests for the two server doorbell vector numbers, and is modified to use a compare instruction rather than an andi. on the single bit difference between 0x500 and 0x900. The last two use a CPU feature section to avoid needlessly testing against the hypervisor vector if it is not the hypervisor, and vice versa. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-11-15 02:49:48 +08:00
#endif /* CONFIG_PPC_DOORBELL */
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
1: b ret_from_except /* What else to do here ? */
powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
2012-03-06 15:27:59 +08:00
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
.Lunrecov_restore:
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
addi r3,r1,STACK_FRAME_OVERHEAD
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl unrecoverable_exception
powerpc/64s: Blacklist functions invoked on a trap Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-30 01:49:19 +08:00
b .Lunrecov_restore
_ASM_NOKPROBE_SYMBOL(ret_from_except);
_ASM_NOKPROBE_SYMBOL(ret_from_except_lite);
_ASM_NOKPROBE_SYMBOL(resume_kernel);
_ASM_NOKPROBE_SYMBOL(fast_exc_return_irq);
_ASM_NOKPROBE_SYMBOL(restore);
_ASM_NOKPROBE_SYMBOL(fast_exception_return);
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
#ifdef CONFIG_PPC_RTAS
/*
* On CHRP, the Run-Time Abstraction Services (RTAS) have to be
* called with the MMU off.
*
* In addition, we need to be in 32b mode, at least for now.
*
* Note: r3 is an input parameter to rtas, so don't trash it...
*/
_GLOBAL(enter_rtas)
mflr r0
std r0,16(r1)
stdu r1,-RTAS_FRAME_SIZE(r1) /* Save SP and create stack space. */
/* Because RTAS is running in 32b mode, it clobbers the high order half
* of all registers that it saves. We therefore save those registers
* RTAS might touch to the stack. (r0, r3-r13 are caller saved)
*/
SAVE_GPR(2, r1) /* Save the TOC */
SAVE_GPR(13, r1) /* Save paca */
SAVE_8GPRS(14, r1) /* Save the non-volatiles */
SAVE_10GPRS(22, r1) /* ditto */
mfcr r4
std r4,_CCR(r1)
mfctr r5
std r5,_CTR(r1)
mfspr r6,SPRN_XER
std r6,_XER(r1)
mfdar r7
std r7,_DAR(r1)
mfdsisr r8
std r8,_DSISR(r1)
[PATCH] powerpc: Workaround for pSeries RTAS bug A bug in the RTAS services incorrectly interprets some bits in the CR when called from the OS. Specifically, bits in CR4. The result could be a firmware crash that also takes down the partition. A firmware fix is in the works. We have seen this situation when performing DLPAR operations. As a temporary workaround, clear the CR in enter_rtas(). Note that enter_rtas() will not set any bits in CR4 before calling RTAS. Also note that the 32 bit version of enter_rtas() should have the same work around even though the chances of hitting the bug are much smaller due to the lack of DLPAR on 32 bit kernels. However, my assembly skills are a bit rusty and the 32 bit code doesn't seem to follow the conventions for where things should be saved. In addition, I don't have a system to test 32 bit kernels. Help creating and at least touch testing the same workaround for 32 bit would be appreciated. Signed-off-by: Mike Kravetz <kravetz@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-28 07:20:00 +08:00
/* Temporary workaround to clear CR until RTAS can be modified to
* ignore all bits.
*/
li r0,0
mtcr r0
[POWERPC] Fix manual assembly WARN_ON() in enter_rtas(). When we switched over to the generic BUG mechanism we forgot to change the assembly code which open-codes a WARN_ON() in enter_rtas(), so the bug table got corrupted. This patch provides an EMIT_BUG_ENTRY macro for use in assembly code, and uses it in entry_64.S. Tested with CONFIG_DEBUG_BUGVERBOSE on ppc64 but not without -- I tried to turn it off but it wouldn't go away; I suspect Aunt Tillie probably needed it. This version gets __FILE__ and __LINE__ right in the assembly version -- rather than saying include/asm-powerpc/bug.h line 21 every time which is a little suboptimal. Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-01-02 02:45:34 +08:00
#ifdef CONFIG_BUG
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* There is no way it is acceptable to get here with interrupts enabled,
* check it with the asm equivalent of WARN_ON
*/
[POWERPC] Lazy interrupt disabling for 64-bit machines This implements a lazy strategy for disabling interrupts. This means that local_irq_disable() et al. just clear the 'interrupts are enabled' flag in the paca. If an interrupt comes along, the interrupt entry code notices that interrupts are supposed to be disabled, and clears the EE bit in SRR1, clears the 'interrupts are hard-enabled' flag in the paca, and returns. This means that interrupts only actually get disabled in the processor when an interrupt comes along. When interrupts are enabled by local_irq_enable() et al., the code sets the interrupts-enabled flag in the paca, and then checks whether interrupts got hard-disabled. If so, it also sets the EE bit in the MSR to hard-enable the interrupts. This has the potential to improve performance, and also makes it easier to make a kernel that can boot on iSeries and on other 64-bit machines, since this lazy-disable strategy is very similar to the soft-disable strategy that iSeries already uses. This version renames paca->proc_enabled to paca->soft_enabled, and changes a couple of soft-disables in the kexec code to hard-disables, which should fix the crash that Michael Ellerman saw. This doesn't yet use a reserved CR field for the soft_enabled and hard_enabled flags. This applies on top of Stephen Rothwell's patches to make it possible to build a combined iSeries/other kernel. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-04 14:47:49 +08:00
lbz r0,PACASOFTIRQEN(r13)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
1: tdnei r0,0
[POWERPC] Fix manual assembly WARN_ON() in enter_rtas(). When we switched over to the generic BUG mechanism we forgot to change the assembly code which open-codes a WARN_ON() in enter_rtas(), so the bug table got corrupted. This patch provides an EMIT_BUG_ENTRY macro for use in assembly code, and uses it in entry_64.S. Tested with CONFIG_DEBUG_BUGVERBOSE on ppc64 but not without -- I tried to turn it off but it wouldn't go away; I suspect Aunt Tillie probably needed it. This version gets __FILE__ and __LINE__ right in the assembly version -- rather than saying include/asm-powerpc/bug.h line 21 every time which is a little suboptimal. Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-01-02 02:45:34 +08:00
EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING
#endif
[POWERPC] Lazy interrupt disabling for 64-bit machines This implements a lazy strategy for disabling interrupts. This means that local_irq_disable() et al. just clear the 'interrupts are enabled' flag in the paca. If an interrupt comes along, the interrupt entry code notices that interrupts are supposed to be disabled, and clears the EE bit in SRR1, clears the 'interrupts are hard-enabled' flag in the paca, and returns. This means that interrupts only actually get disabled in the processor when an interrupt comes along. When interrupts are enabled by local_irq_enable() et al., the code sets the interrupts-enabled flag in the paca, and then checks whether interrupts got hard-disabled. If so, it also sets the EE bit in the MSR to hard-enable the interrupts. This has the potential to improve performance, and also makes it easier to make a kernel that can boot on iSeries and on other 64-bit machines, since this lazy-disable strategy is very similar to the soft-disable strategy that iSeries already uses. This version renames paca->proc_enabled to paca->soft_enabled, and changes a couple of soft-disables in the kexec code to hard-disables, which should fix the crash that Michael Ellerman saw. This doesn't yet use a reserved CR field for the soft_enabled and hard_enabled flags. This applies on top of Stephen Rothwell's patches to make it possible to build a combined iSeries/other kernel. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-04 14:47:49 +08:00
/* Hard-disable interrupts */
mfmsr r6
rldicl r7,r6,48,1
rotldi r7,r7,16
mtmsrd r7,1
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* Unfortunately, the stack pointer and the MSR are also clobbered,
* so they are saved in the PACA which allows us to restore
* our original state after RTAS returns.
*/
std r1,PACAR1(r13)
std r6,PACASAVEDMSR(r13)
/* Setup our real return addr */
powerpc: Remove superflous function descriptors in assembly only code We have a number of places where we load the text address of a local function and indirectly branch to it in assembly. Since it is an indirect branch binutils will not know to use the function text address, so that trick wont work. There is no need for these functions to have a function descriptor so we can replace it with a label and remove the dot symbol. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:52 +08:00
LOAD_REG_ADDR(r4,rtas_return_loc)
[PATCH] powerpc: Cleanup LOADADDR etc. asm macros This patch consolidates the variety of macros used for loading 32 or 64-bit constants in assembler (LOADADDR, LOADBASE, SET_REG_TO_*). The idea is to make the set of macros consistent across 32 and 64 bit and to make it more obvious which is the appropriate one to use in a given situation. The new macros and their semantics are described in the comments in ppc_asm.h. In the process, we change several places that were unnecessarily using immediate loads on ppc64 to use the GOT/TOC. Likewise we cleanup a couple of places where we were clumsily subtracting PAGE_OFFSET with asm instructions to use assemble-time arithmetic or the toreal() macro instead. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-13 11:56:25 +08:00
clrldi r4,r4,2 /* convert to realmode address */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
mtlr r4
li r0,0
ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI
andc r0,r6,r0
li r9,1
rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG)
powerpc: Endian safe trampoline Create a trampoline that works in either endian and flips to the expected endian. Use it for primary and secondary thread entry as well as RTAS and OF call return. Credit for finding the magic instruction goes to Paul Mackerras Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-23 10:04:45 +08:00
ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
andc r6,r0,r9
sync /* disable interrupts so SRR0/1 */
mtmsrd r0 /* don't get trashed */
[PATCH] powerpc: Cleanup LOADADDR etc. asm macros This patch consolidates the variety of macros used for loading 32 or 64-bit constants in assembler (LOADADDR, LOADBASE, SET_REG_TO_*). The idea is to make the set of macros consistent across 32 and 64 bit and to make it more obvious which is the appropriate one to use in a given situation. The new macros and their semantics are described in the comments in ppc_asm.h. In the process, we change several places that were unnecessarily using immediate loads on ppc64 to use the GOT/TOC. Likewise we cleanup a couple of places where we were clumsily subtracting PAGE_OFFSET with asm instructions to use assemble-time arithmetic or the toreal() macro instead. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-13 11:56:25 +08:00
LOAD_REG_ADDR(r4, rtas)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r5,RTASENTRY(r4) /* get the rtas->entry value */
ld r4,RTASBASE(r4) /* get the rtas->base value */
mtspr SPRN_SRR0,r5
mtspr SPRN_SRR1,r6
rfid
b . /* prevent speculative execution */
powerpc: Remove superflous function descriptors in assembly only code We have a number of places where we load the text address of a local function and indirectly branch to it in assembly. Since it is an indirect branch binutils will not know to use the function text address, so that trick wont work. There is no need for these functions to have a function descriptor so we can replace it with a label and remove the dot symbol. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:52 +08:00
rtas_return_loc:
powerpc: Endian safe trampoline Create a trampoline that works in either endian and flips to the expected endian. Use it for primary and secondary thread entry as well as RTAS and OF call return. Credit for finding the magic instruction goes to Paul Mackerras Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-23 10:04:45 +08:00
FIXUP_ENDIAN
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* relocation is off at this point */
powerpc: In HV mode, use HSPRG0 for PACA When running in Hypervisor mode (arch 2.06 or later), we store the PACA in HSPRG0 instead of SPRG1. The architecture specifies that SPRGs may be lost during a "nap" power management operation (though they aren't currently on POWER7) and this enables use of SPRG1 by KVM guests. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-20 14:50:21 +08:00
GET_PACA(r4)
[PATCH] powerpc: Cleanup LOADADDR etc. asm macros This patch consolidates the variety of macros used for loading 32 or 64-bit constants in assembler (LOADADDR, LOADBASE, SET_REG_TO_*). The idea is to make the set of macros consistent across 32 and 64 bit and to make it more obvious which is the appropriate one to use in a given situation. The new macros and their semantics are described in the comments in ppc_asm.h. In the process, we change several places that were unnecessarily using immediate loads on ppc64 to use the GOT/TOC. Likewise we cleanup a couple of places where we were clumsily subtracting PAGE_OFFSET with asm instructions to use assemble-time arithmetic or the toreal() macro instead. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-13 11:56:25 +08:00
clrldi r4,r4,2 /* convert to realmode address */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: Use LOAD_REG_IMMEDIATE only for constants on 64-bit Using LOAD_REG_IMMEDIATE to get the address of kernel symbols generates 5 instructions where LOAD_REG_ADDR can do it in one, and will generate R_PPC64_ADDR16_* relocations in the output when we get to making the kernel as a position-independent executable, which we'd rather not have to handle. This changes various bits of assembly code to use LOAD_REG_ADDR when we need to get the address of a symbol, or to use suitable position-independent code for cases where we can't access the TOC for various reasons, or if we're not running at the address we were linked at. It also cleans up a few minor things; there's no reason to save and restore SRR0/1 around RTAS calls, __mmu_off can get the return address from LR more conveniently than the caller can supply it in R4 (and we already assume elsewhere that EA == RA if the MMU is on in early boot), and enable_64b_mode was using 5 instructions where 2 would do. Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-08-30 09:41:12 +08:00
bcl 20,31,$+4
0: mflr r3
powerpc: Remove superflous function descriptors in assembly only code We have a number of places where we load the text address of a local function and indirectly branch to it in assembly. Since it is an indirect branch binutils will not know to use the function text address, so that trick wont work. There is no need for these functions to have a function descriptor so we can replace it with a label and remove the dot symbol. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:52 +08:00
ld r3,(1f-0b)(r3) /* get &rtas_restore_regs */
powerpc: Use LOAD_REG_IMMEDIATE only for constants on 64-bit Using LOAD_REG_IMMEDIATE to get the address of kernel symbols generates 5 instructions where LOAD_REG_ADDR can do it in one, and will generate R_PPC64_ADDR16_* relocations in the output when we get to making the kernel as a position-independent executable, which we'd rather not have to handle. This changes various bits of assembly code to use LOAD_REG_ADDR when we need to get the address of a symbol, or to use suitable position-independent code for cases where we can't access the TOC for various reasons, or if we're not running at the address we were linked at. It also cleans up a few minor things; there's no reason to save and restore SRR0/1 around RTAS calls, __mmu_off can get the return address from LR more conveniently than the caller can supply it in R4 (and we already assume elsewhere that EA == RA if the MMU is on in early boot), and enable_64b_mode was using 5 instructions where 2 would do. Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-08-30 09:41:12 +08:00
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
mfmsr r6
li r0,MSR_RI
andc r6,r6,r0
sync
mtmsrd r6
ld r1,PACAR1(r4) /* Restore our SP */
ld r4,PACASAVEDMSR(r4) /* Restore our MSR */
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
rfid
b . /* prevent speculative execution */
powerpc: Use LOAD_REG_IMMEDIATE only for constants on 64-bit Using LOAD_REG_IMMEDIATE to get the address of kernel symbols generates 5 instructions where LOAD_REG_ADDR can do it in one, and will generate R_PPC64_ADDR16_* relocations in the output when we get to making the kernel as a position-independent executable, which we'd rather not have to handle. This changes various bits of assembly code to use LOAD_REG_ADDR when we need to get the address of a symbol, or to use suitable position-independent code for cases where we can't access the TOC for various reasons, or if we're not running at the address we were linked at. It also cleans up a few minor things; there's no reason to save and restore SRR0/1 around RTAS calls, __mmu_off can get the return address from LR more conveniently than the caller can supply it in R4 (and we already assume elsewhere that EA == RA if the MMU is on in early boot), and enable_64b_mode was using 5 instructions where 2 would do. Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-08-30 09:41:12 +08:00
.align 3
powerpc: Remove superflous function descriptors in assembly only code We have a number of places where we load the text address of a local function and indirectly branch to it in assembly. Since it is an indirect branch binutils will not know to use the function text address, so that trick wont work. There is no need for these functions to have a function descriptor so we can replace it with a label and remove the dot symbol. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:52 +08:00
1: .llong rtas_restore_regs
powerpc: Use LOAD_REG_IMMEDIATE only for constants on 64-bit Using LOAD_REG_IMMEDIATE to get the address of kernel symbols generates 5 instructions where LOAD_REG_ADDR can do it in one, and will generate R_PPC64_ADDR16_* relocations in the output when we get to making the kernel as a position-independent executable, which we'd rather not have to handle. This changes various bits of assembly code to use LOAD_REG_ADDR when we need to get the address of a symbol, or to use suitable position-independent code for cases where we can't access the TOC for various reasons, or if we're not running at the address we were linked at. It also cleans up a few minor things; there's no reason to save and restore SRR0/1 around RTAS calls, __mmu_off can get the return address from LR more conveniently than the caller can supply it in R4 (and we already assume elsewhere that EA == RA if the MMU is on in early boot), and enable_64b_mode was using 5 instructions where 2 would do. Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-08-30 09:41:12 +08:00
powerpc: Remove superflous function descriptors in assembly only code We have a number of places where we load the text address of a local function and indirectly branch to it in assembly. Since it is an indirect branch binutils will not know to use the function text address, so that trick wont work. There is no need for these functions to have a function descriptor so we can replace it with a label and remove the dot symbol. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:52 +08:00
rtas_restore_regs:
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* relocation is on at this point */
REST_GPR(2, r1) /* Restore the TOC */
REST_GPR(13, r1) /* Restore paca */
REST_8GPRS(14, r1) /* Restore the non-volatiles */
REST_10GPRS(22, r1) /* ditto */
powerpc: In HV mode, use HSPRG0 for PACA When running in Hypervisor mode (arch 2.06 or later), we store the PACA in HSPRG0 instead of SPRG1. The architecture specifies that SPRGs may be lost during a "nap" power management operation (though they aren't currently on POWER7) and this enables use of SPRG1 by KVM guests. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-20 14:50:21 +08:00
GET_PACA(r13)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
ld r4,_CCR(r1)
mtcr r4
ld r5,_CTR(r1)
mtctr r5
ld r6,_XER(r1)
mtspr SPRN_XER,r6
ld r7,_DAR(r1)
mtdar r7
ld r8,_DSISR(r1)
mtdsisr r8
addi r1,r1,RTAS_FRAME_SIZE /* Unstack our frame */
ld r0,16(r1) /* get return address */
mtlr r0
blr /* return to caller */
#endif /* CONFIG_PPC_RTAS */
_GLOBAL(enter_prom)
mflr r0
std r0,16(r1)
stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
/* Because PROM is running in 32b mode, it clobbers the high order half
* of all registers that it saves. We therefore save those registers
* PROM might touch to the stack. (r0, r3-r13 are caller saved)
*/
powerpc/of: Remove useless register save/restore when calling OF back enter_prom() used to save and restore registers such as CTR, XER etc.. which are volatile, or SRR0,1... which we don't care about. This removes a bunch of useless code and while at it turns an mtmsrd into an MTMSRD macro which will be useful to Book3E. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:07 +08:00
SAVE_GPR(2, r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
SAVE_GPR(13, r1)
SAVE_8GPRS(14, r1)
SAVE_10GPRS(22, r1)
powerpc/of: Remove useless register save/restore when calling OF back enter_prom() used to save and restore registers such as CTR, XER etc.. which are volatile, or SRR0,1... which we don't care about. This removes a bunch of useless code and while at it turns an mtmsrd into an MTMSRD macro which will be useful to Book3E. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:07 +08:00
mfcr r10
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
mfmsr r11
powerpc/of: Remove useless register save/restore when calling OF back enter_prom() used to save and restore registers such as CTR, XER etc.. which are volatile, or SRR0,1... which we don't care about. This removes a bunch of useless code and while at it turns an mtmsrd into an MTMSRD macro which will be useful to Book3E. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:07 +08:00
std r10,_CCR(r1)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
std r11,_MSR(r1)
powerpc: Endian safe trampoline Create a trampoline that works in either endian and flips to the expected endian. Use it for primary and secondary thread entry as well as RTAS and OF call return. Credit for finding the magic instruction goes to Paul Mackerras Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-23 10:04:45 +08:00
/* Put PROM address in SRR0 */
mtsrr0 r4
/* Setup our trampoline return addr in LR */
bcl 20,31,$+4
0: mflr r4
addi r4,r4,(1f - 0b)
mtlr r4
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: Endian safe trampoline Create a trampoline that works in either endian and flips to the expected endian. Use it for primary and secondary thread entry as well as RTAS and OF call return. Credit for finding the magic instruction goes to Paul Mackerras Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-23 10:04:45 +08:00
/* Prepare a 32-bit mode big endian MSR
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
*/
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#ifdef CONFIG_PPC_BOOK3E
rlwinm r11,r11,0,1,31
powerpc: Endian safe trampoline Create a trampoline that works in either endian and flips to the expected endian. Use it for primary and secondary thread entry as well as RTAS and OF call return. Credit for finding the magic instruction goes to Paul Mackerras Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-23 10:04:45 +08:00
mtsrr1 r11
rfi
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#else /* CONFIG_PPC_BOOK3E */
powerpc: Endian safe trampoline Create a trampoline that works in either endian and flips to the expected endian. Use it for primary and secondary thread entry as well as RTAS and OF call return. Credit for finding the magic instruction goes to Paul Mackerras Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-23 10:04:45 +08:00
LOAD_REG_IMMEDIATE(r12, MSR_SF | MSR_ISF | MSR_LE)
andc r11,r11,r12
mtsrr1 r11
rfid
powerpc: Remaining 64-bit Book3E support This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:59 +08:00
#endif /* CONFIG_PPC_BOOK3E */
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
powerpc: Endian safe trampoline Create a trampoline that works in either endian and flips to the expected endian. Use it for primary and secondary thread entry as well as RTAS and OF call return. Credit for finding the magic instruction goes to Paul Mackerras Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-23 10:04:45 +08:00
1: /* Return from OF */
FIXUP_ENDIAN
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
/* Just make sure that r1 top 32 bits didn't get
* corrupt by OF
*/
rldicl r1,r1,0,32
/* Restore the MSR (back to 64 bits) */
ld r0,_MSR(r1)
powerpc/of: Remove useless register save/restore when calling OF back enter_prom() used to save and restore registers such as CTR, XER etc.. which are volatile, or SRR0,1... which we don't care about. This removes a bunch of useless code and while at it turns an mtmsrd into an MTMSRD macro which will be useful to Book3E. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-07-24 07:15:07 +08:00
MTMSRD(r0)
powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S The system call table has been consolidated into systbl.S. We have separate 32-bit and 64-bit versions of entry.S and misc.S since the code is mostly sufficiently different to be not worth merging. There are some common bits that will be extracted in future. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:36:14 +08:00
isync
/* Restore other registers */
REST_GPR(2, r1)
REST_GPR(13, r1)
REST_8GPRS(14, r1)
REST_10GPRS(22, r1)
ld r4,_CCR(r1)
mtcr r4
addi r1,r1,PROM_FRAME_SIZE
ld r0,16(r1)
mtlr r0
blr