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linux/arch/powerpc/kernel/fpu.S

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powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
/*
* FPU support code, moved here from head.S so that it can be used
* by chips which use other head-whatever.S files.
*
[POWERPC] Restore copyright notice in arch/powerpc/kernel/fpu.S This code got moved from head.S but the copyright notice on head.S didn't get transferred with it. Noticed by Cort Dougan <cort@fsmlabs.com>. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-08-30 12:45:35 +08:00
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
* Copyright (C) 1996 Paul Mackerras.
* Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
*
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
* 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.
*
*/
powerpc: Use reg.h instead of processor.h when we just want reg names Now that the register names and bit definitions are all in reg.h, use that instead of processor.h in assembly code in a few places. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-10 20:20:10 +08:00
#include <asm/reg.h>
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/cputable.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
powerpc: Remove second definition of STACK_FRAME_OVERHEAD Since STACK_FRAME_OVERHEAD is defined in asm/ptrace.h and that is ASSEMBER safe, we can just include that instead of going via asm-offsets.h. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-11-18 23:06:17 +08:00
#include <asm/ptrace.h>
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
powerpc: Add VSX assembler code macros This adds the macros for the VSX load/store instruction as most binutils are not going to support this for a while. Also add VSX register save/restore macros and vsr[0-63] register definitions. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-25 12:07:18 +08:00
#ifdef CONFIG_VSX
powerpc: Enforce usage of R0-R31 where possible Enforce the use of R0-R31 in macros where possible now we have all the fixes in. R0-R31 macros are removed here so that can't be used anymore. They should not be defined anywhere. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:23 +08:00
#define __REST_32FPVSRS(n,c,base) \
powerpc: Add VSX assembler code macros This adds the macros for the VSX load/store instruction as most binutils are not going to support this for a while. Also add VSX register save/restore macros and vsr[0-63] register definitions. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-25 12:07:18 +08:00
BEGIN_FTR_SECTION \
b 2f; \
END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
REST_32FPRS(n,base); \
b 3f; \
2: REST_32VSRS(n,c,base); \
3:
powerpc: Enforce usage of R0-R31 where possible Enforce the use of R0-R31 in macros where possible now we have all the fixes in. R0-R31 macros are removed here so that can't be used anymore. They should not be defined anywhere. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:23 +08:00
#define __SAVE_32FPVSRS(n,c,base) \
powerpc: Add VSX assembler code macros This adds the macros for the VSX load/store instruction as most binutils are not going to support this for a while. Also add VSX register save/restore macros and vsr[0-63] register definitions. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-25 12:07:18 +08:00
BEGIN_FTR_SECTION \
b 2f; \
END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
SAVE_32FPRS(n,base); \
b 3f; \
2: SAVE_32VSRS(n,c,base); \
3:
#else
powerpc: Enforce usage of R0-R31 where possible Enforce the use of R0-R31 in macros where possible now we have all the fixes in. R0-R31 macros are removed here so that can't be used anymore. They should not be defined anywhere. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:23 +08:00
#define __REST_32FPVSRS(n,b,base) REST_32FPRS(n, base)
#define __SAVE_32FPVSRS(n,b,base) SAVE_32FPRS(n, base)
powerpc: Add VSX assembler code macros This adds the macros for the VSX load/store instruction as most binutils are not going to support this for a while. Also add VSX register save/restore macros and vsr[0-63] register definitions. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-25 12:07:18 +08:00
#endif
powerpc: Enforce usage of R0-R31 where possible Enforce the use of R0-R31 in macros where possible now we have all the fixes in. R0-R31 macros are removed here so that can't be used anymore. They should not be defined anywhere. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:23 +08:00
#define REST_32FPVSRS(n,c,base) __REST_32FPVSRS(n,__REG_##c,__REG_##base)
#define SAVE_32FPVSRS(n,c,base) __SAVE_32FPVSRS(n,__REG_##c,__REG_##base)
powerpc: Add VSX assembler code macros This adds the macros for the VSX load/store instruction as most binutils are not going to support this for a while. Also add VSX register save/restore macros and vsr[0-63] register definitions. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-25 12:07:18 +08:00
powerpc: Add FP/VSX and VMX register load functions for transactional memory This adds functions to restore the state of the FP/VSX registers from what's stored in the thread_struct. Two version for FP/VSX are required since one restores them from transactional/checkpoint side of the thread_struct and the other from the speculated side. Similar functions are added for VMX registers. 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 00:21:36 +08:00
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/* void do_load_up_transact_fpu(struct thread_struct *thread)
*
* This is similar to load_up_fpu but for the transactional version of the FP
* register set. It doesn't mess with the task MSR or valid flags.
* Furthermore, we don't do lazy FP with TM currently.
*/
_GLOBAL(do_load_up_transact_fpu)
mfmsr r6
ori r5,r6,MSR_FP
#ifdef CONFIG_VSX
BEGIN_FTR_SECTION
oris r5,r5,MSR_VSX@h
END_FTR_SECTION_IFSET(CPU_FTR_VSX)
#endif
SYNC
MTMSRD(r5)
powerpc: Put FP/VSX and VR state into structures This creates new 'thread_fp_state' and 'thread_vr_state' structures to store FP/VSX state (including FPSCR) and Altivec/VSX state (including VSCR), and uses them in the thread_struct. In the thread_fp_state, the FPRs and VSRs are represented as u64 rather than double, since we rarely perform floating-point computations on the values, and this will enable the structures to be used in KVM code as well. Similarly FPSCR is now a u64 rather than a structure of two 32-bit values. This takes the offsets out of the macros such as SAVE_32FPRS, REST_32FPRS, etc. This enables the same macros to be used for normal and transactional state, enabling us to delete the transactional versions of the macros. This also removes the unused do_load_up_fpu and do_load_up_altivec, which were in fact buggy since they didn't create large enough stack frames to account for the fact that load_up_fpu and load_up_altivec are not designed to be called from C and assume that their caller's stack frame is an interrupt frame. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-10 18:20:42 +08:00
addi r7,r3,THREAD_TRANSACT_FPSTATE
lfd fr0,FPSTATE_FPSCR(r7)
powerpc: Add FP/VSX and VMX register load functions for transactional memory This adds functions to restore the state of the FP/VSX registers from what's stored in the thread_struct. Two version for FP/VSX are required since one restores them from transactional/checkpoint side of the thread_struct and the other from the speculated side. Similar functions are added for VMX registers. 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 00:21:36 +08:00
MTFSF_L(fr0)
powerpc: Put FP/VSX and VR state into structures This creates new 'thread_fp_state' and 'thread_vr_state' structures to store FP/VSX state (including FPSCR) and Altivec/VSX state (including VSCR), and uses them in the thread_struct. In the thread_fp_state, the FPRs and VSRs are represented as u64 rather than double, since we rarely perform floating-point computations on the values, and this will enable the structures to be used in KVM code as well. Similarly FPSCR is now a u64 rather than a structure of two 32-bit values. This takes the offsets out of the macros such as SAVE_32FPRS, REST_32FPRS, etc. This enables the same macros to be used for normal and transactional state, enabling us to delete the transactional versions of the macros. This also removes the unused do_load_up_fpu and do_load_up_altivec, which were in fact buggy since they didn't create large enough stack frames to account for the fact that load_up_fpu and load_up_altivec are not designed to be called from C and assume that their caller's stack frame is an interrupt frame. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-10 18:20:42 +08:00
REST_32FPVSRS(0, R4, R7)
powerpc: Add FP/VSX and VMX register load functions for transactional memory This adds functions to restore the state of the FP/VSX registers from what's stored in the thread_struct. Two version for FP/VSX are required since one restores them from transactional/checkpoint side of the thread_struct and the other from the speculated side. Similar functions are added for VMX registers. 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 00:21:36 +08:00
blr
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
powerpc: Provide for giveup_fpu/altivec to save state in alternate location This provides a facility which is intended for use by KVM, where the contents of the FP/VSX and VMX (Altivec) registers can be saved away to somewhere other than the thread_struct when kernel code wants to use floating point or VMX instructions. This is done by providing a pointer in the thread_struct to indicate where the state should be saved to. The giveup_fpu() and giveup_altivec() functions test these pointers and save state to the indicated location if they are non-NULL. Note that the MSR_FP/VEC bits in task->thread.regs->msr are still used to indicate whether the CPU register state is live, even when an alternate save location is being used. This also provides load_fp_state() and load_vr_state() functions, which load up FP/VSX and VMX state from memory into the CPU registers, and corresponding store_fp_state() and store_vr_state() functions, which store FP/VSX and VMX state into memory from the CPU registers. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-10 18:21:10 +08:00
/*
* Load state from memory into FP registers including FPSCR.
* Assumes the caller has enabled FP in the MSR.
*/
_GLOBAL(load_fp_state)
lfd fr0,FPSTATE_FPSCR(r3)
MTFSF_L(fr0)
REST_32FPVSRS(0, R4, R3)
blr
/*
* Store FP state into memory, including FPSCR
* Assumes the caller has enabled FP in the MSR.
*/
_GLOBAL(store_fp_state)
SAVE_32FPVSRS(0, R4, R3)
mffs fr0
stfd fr0,FPSTATE_FPSCR(r3)
blr
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
/*
* This task wants to use the FPU now.
* On UP, disable FP for the task which had the FPU previously,
* and save its floating-point registers in its thread_struct.
* Load up this task's FP registers from its thread_struct,
* enable the FPU for the current task and return to the task.
powerpc: Don't corrupt user registers on 32-bit Commit de79f7b9f6 ("powerpc: Put FP/VSX and VR state into structures") modified load_up_fpu() and load_up_altivec() in such a way that they now use r7 and r8. Unfortunately, the callers of these functions on 32-bit machines then return to userspace via fast_exception_return, which doesn't restore all of the volatile GPRs, but only r1, r3 -- r6 and r9 -- r12. This was causing userspace segfaults and other userspace misbehaviour on 32-bit machines. This fixes the problem by changing the register usage of load_up_fpu() and load_up_altivec() to avoid using r7 and r8 and instead use r6 and r10. This also adds comments to those functions saying which registers may be used. Signed-off-by: Paul Mackerras <paulus@samba.org> Tested-by: Scott Wood <scottwood@freescale.com> (on e500mc, so no altivec) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-23 16:40:02 +08:00
* Note that on 32-bit this can only use registers that will be
* restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
*/
powerpc: Define 32/64 bit asm macros and use them in fpu.S These macros help in writing assembly code that works for both ppc32 and ppc64. With this we now have a common fpu.S. This takes out load_up_fpu from head_64.S. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-06 08:59:19 +08:00
_GLOBAL(load_up_fpu)
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
mfmsr r5
ori r5,r5,MSR_FP
powerpc: Add VSX context save/restore, ptrace and signal support This patch extends the floating point save and restore code to use the VSX load/stores when VSX is available. This will make FP context save/restore marginally slower on FP only code, when VSX is available, as it has to load/store 128bits rather than just 64bits. Mixing FP, VMX and VSX code will get constant architected state. The signals interface is extended to enable access to VSR 0-31 doubleword 1 after discussions with tool chain maintainers. Backward compatibility is maintained. The ptrace interface is also extended to allow access to VSR 0-31 full registers. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-25 12:07:18 +08:00
#ifdef CONFIG_VSX
BEGIN_FTR_SECTION
oris r5,r5,MSR_VSX@h
END_FTR_SECTION_IFSET(CPU_FTR_VSX)
#endif
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
SYNC
MTMSRD(r5) /* enable use of fpu now */
isync
/* enable use of FP after return */
powerpc: Define 32/64 bit asm macros and use them in fpu.S These macros help in writing assembly code that works for both ppc32 and ppc64. With this we now have a common fpu.S. This takes out load_up_fpu from head_64.S. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-06 08:59:19 +08:00
#ifdef CONFIG_PPC32
powerpc: Put FP/VSX and VR state into structures This creates new 'thread_fp_state' and 'thread_vr_state' structures to store FP/VSX state (including FPSCR) and Altivec/VSX state (including VSCR), and uses them in the thread_struct. In the thread_fp_state, the FPRs and VSRs are represented as u64 rather than double, since we rarely perform floating-point computations on the values, and this will enable the structures to be used in KVM code as well. Similarly FPSCR is now a u64 rather than a structure of two 32-bit values. This takes the offsets out of the macros such as SAVE_32FPRS, REST_32FPRS, etc. This enables the same macros to be used for normal and transactional state, enabling us to delete the transactional versions of the macros. This also removes the unused do_load_up_fpu and do_load_up_altivec, which were in fact buggy since they didn't create large enough stack frames to account for the fact that load_up_fpu and load_up_altivec are not designed to be called from C and assume that their caller's stack frame is an interrupt frame. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-10 18:20:42 +08:00
mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
lwz r4,THREAD_FPEXC_MODE(r5)
ori r9,r9,MSR_FP /* enable FP for current */
or r9,r9,r4
powerpc: Define 32/64 bit asm macros and use them in fpu.S These macros help in writing assembly code that works for both ppc32 and ppc64. With this we now have a common fpu.S. This takes out load_up_fpu from head_64.S. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-06 08:59:19 +08:00
#else
ld r4,PACACURRENT(r13)
addi r5,r4,THREAD /* Get THREAD */
powerpc/64: Fix bug in setting floating-point exception mode When loading up the FPU, we were using a 'ld' (load doubleword) instruction to get the FP exception mode from the thread_struct, but it's only an int field. This changes the ld to lwz (load word and zero-extend). Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-02-07 10:55:30 +08:00
lwz r4,THREAD_FPEXC_MODE(r5)
powerpc: Define 32/64 bit asm macros and use them in fpu.S These macros help in writing assembly code that works for both ppc32 and ppc64. With this we now have a common fpu.S. This takes out load_up_fpu from head_64.S. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-06 08:59:19 +08:00
ori r12,r12,MSR_FP
or r12,r12,r4
std r12,_MSR(r1)
#endif
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
/* Don't care if r4 overflows, this is desired behaviour */
lbz r4,THREAD_LOAD_FP(r5)
addi r4,r4,1
stb r4,THREAD_LOAD_FP(r5)
powerpc: Don't corrupt user registers on 32-bit Commit de79f7b9f6 ("powerpc: Put FP/VSX and VR state into structures") modified load_up_fpu() and load_up_altivec() in such a way that they now use r7 and r8. Unfortunately, the callers of these functions on 32-bit machines then return to userspace via fast_exception_return, which doesn't restore all of the volatile GPRs, but only r1, r3 -- r6 and r9 -- r12. This was causing userspace segfaults and other userspace misbehaviour on 32-bit machines. This fixes the problem by changing the register usage of load_up_fpu() and load_up_altivec() to avoid using r7 and r8 and instead use r6 and r10. This also adds comments to those functions saying which registers may be used. Signed-off-by: Paul Mackerras <paulus@samba.org> Tested-by: Scott Wood <scottwood@freescale.com> (on e500mc, so no altivec) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-23 16:40:02 +08:00
addi r10,r5,THREAD_FPSTATE
lfd fr0,FPSTATE_FPSCR(r10)
[POWERPC] 64bit FPSCR support Forthcoming machines will extend the FPSCR to 64 bits. We already had a 64-bit save area for the FPSCR, but we need to use a new form of the mtfsf instruction. Fortunately this new form is decoded as an ordinary mtfsf by existing 64-bit processors. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-06-10 18:18:39 +08:00
MTFSF_L(fr0)
powerpc: Don't corrupt user registers on 32-bit Commit de79f7b9f6 ("powerpc: Put FP/VSX and VR state into structures") modified load_up_fpu() and load_up_altivec() in such a way that they now use r7 and r8. Unfortunately, the callers of these functions on 32-bit machines then return to userspace via fast_exception_return, which doesn't restore all of the volatile GPRs, but only r1, r3 -- r6 and r9 -- r12. This was causing userspace segfaults and other userspace misbehaviour on 32-bit machines. This fixes the problem by changing the register usage of load_up_fpu() and load_up_altivec() to avoid using r7 and r8 and instead use r6 and r10. This also adds comments to those functions saying which registers may be used. Signed-off-by: Paul Mackerras <paulus@samba.org> Tested-by: Scott Wood <scottwood@freescale.com> (on e500mc, so no altivec) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-23 16:40:02 +08:00
REST_32FPVSRS(0, R4, R10)
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
/* restore registers and return */
/* we haven't used ctr or xer or lr */
powerpc: Make load_up_fpu and load_up_altivec callable Make load_up_fpu and load_up_altivec callable so they can be reused by the VSX code. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-25 12:07:18 +08:00
blr
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
/*
powerpc: Add the ability to save FPU without giving it up This patch adds the ability to be able to save the FPU registers to the thread struct without giving up (disabling the facility) next time the process returns to userspace. This patch optimises the thread copy path (as a result of a fork() or clone()) so that the parent thread can return to userspace with hot registers avoiding a possibly pointless reload of FPU register state. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 14:53:49 +08:00
* save_fpu(tsk)
* Save the floating-point registers in its thread_struct.
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
* Enables the FPU for use in the kernel on return.
*/
powerpc: Add the ability to save FPU without giving it up This patch adds the ability to be able to save the FPU registers to the thread struct without giving up (disabling the facility) next time the process returns to userspace. This patch optimises the thread copy path (as a result of a fork() or clone()) so that the parent thread can return to userspace with hot registers avoiding a possibly pointless reload of FPU register state. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 14:53:49 +08:00
_GLOBAL(save_fpu)
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
addi r3,r3,THREAD /* want THREAD of task */
powerpc: Provide for giveup_fpu/altivec to save state in alternate location This provides a facility which is intended for use by KVM, where the contents of the FP/VSX and VMX (Altivec) registers can be saved away to somewhere other than the thread_struct when kernel code wants to use floating point or VMX instructions. This is done by providing a pointer in the thread_struct to indicate where the state should be saved to. The giveup_fpu() and giveup_altivec() functions test these pointers and save state to the indicated location if they are non-NULL. Note that the MSR_FP/VEC bits in task->thread.regs->msr are still used to indicate whether the CPU register state is live, even when an alternate save location is being used. This also provides load_fp_state() and load_vr_state() functions, which load up FP/VSX and VMX state from memory into the CPU registers, and corresponding store_fp_state() and store_vr_state() functions, which store FP/VSX and VMX state into memory from the CPU registers. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-10 18:21:10 +08:00
PPC_LL r6,THREAD_FPSAVEAREA(r3)
[PATCH] powerpc: Consolidate asm compatibility macros This patch consolidates macros used to generate assembly for compatibility across different CPUs or configs. A new header, asm-powerpc/asm-compat.h contains the main compatibility macros. It uses some preprocessor magic to make the macros suitable both for use in .S files, and in inline asm in .c files. Headers (bitops.h, uaccess.h, atomic.h, bug.h) which had their own such compatibility macros are changed to use asm-compat.h. ppc_asm.h is now for use in .S files *only*, and a #error enforces that. As such, we're a lot more careless about namespace pollution here than in asm-compat.h. While we're at it, this patch adds a call to the PPC405_ERR77 macro in futex.h which should have had it already, but didn't. Built and booted on pSeries, Maple and iSeries (ARCH=powerpc). Built for 32-bit powermac (ARCH=powerpc) and Walnut (ARCH=ppc). Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-10 09:56:55 +08:00
PPC_LL r5,PT_REGS(r3)
powerpc: Provide for giveup_fpu/altivec to save state in alternate location This provides a facility which is intended for use by KVM, where the contents of the FP/VSX and VMX (Altivec) registers can be saved away to somewhere other than the thread_struct when kernel code wants to use floating point or VMX instructions. This is done by providing a pointer in the thread_struct to indicate where the state should be saved to. The giveup_fpu() and giveup_altivec() functions test these pointers and save state to the indicated location if they are non-NULL. Note that the MSR_FP/VEC bits in task->thread.regs->msr are still used to indicate whether the CPU register state is live, even when an alternate save location is being used. This also provides load_fp_state() and load_vr_state() functions, which load up FP/VSX and VMX state from memory into the CPU registers, and corresponding store_fp_state() and store_vr_state() functions, which store FP/VSX and VMX state into memory from the CPU registers. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-10 18:21:10 +08:00
PPC_LCMPI 0,r6,0
bne 2f
powerpc: Put FP/VSX and VR state into structures This creates new 'thread_fp_state' and 'thread_vr_state' structures to store FP/VSX state (including FPSCR) and Altivec/VSX state (including VSCR), and uses them in the thread_struct. In the thread_fp_state, the FPRs and VSRs are represented as u64 rather than double, since we rarely perform floating-point computations on the values, and this will enable the structures to be used in KVM code as well. Similarly FPSCR is now a u64 rather than a structure of two 32-bit values. This takes the offsets out of the macros such as SAVE_32FPRS, REST_32FPRS, etc. This enables the same macros to be used for normal and transactional state, enabling us to delete the transactional versions of the macros. This also removes the unused do_load_up_fpu and do_load_up_altivec, which were in fact buggy since they didn't create large enough stack frames to account for the fact that load_up_fpu and load_up_altivec are not designed to be called from C and assume that their caller's stack frame is an interrupt frame. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-10 18:20:42 +08:00
addi r6,r3,THREAD_FPSTATE
powerpc: Add the ability to save FPU without giving it up This patch adds the ability to be able to save the FPU registers to the thread struct without giving up (disabling the facility) next time the process returns to userspace. This patch optimises the thread copy path (as a result of a fork() or clone()) so that the parent thread can return to userspace with hot registers avoiding a possibly pointless reload of FPU register state. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 14:53:49 +08:00
2: SAVE_32FPVSRS(0, R4, R6)
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
mffs fr0
powerpc: Put FP/VSX and VR state into structures This creates new 'thread_fp_state' and 'thread_vr_state' structures to store FP/VSX state (including FPSCR) and Altivec/VSX state (including VSCR), and uses them in the thread_struct. In the thread_fp_state, the FPRs and VSRs are represented as u64 rather than double, since we rarely perform floating-point computations on the values, and this will enable the structures to be used in KVM code as well. Similarly FPSCR is now a u64 rather than a structure of two 32-bit values. This takes the offsets out of the macros such as SAVE_32FPRS, REST_32FPRS, etc. This enables the same macros to be used for normal and transactional state, enabling us to delete the transactional versions of the macros. This also removes the unused do_load_up_fpu and do_load_up_altivec, which were in fact buggy since they didn't create large enough stack frames to account for the fact that load_up_fpu and load_up_altivec are not designed to be called from C and assume that their caller's stack frame is an interrupt frame. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-10 18:20:42 +08:00
stfd fr0,FPSTATE_FPSCR(r6)
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-09-26 14:04:21 +08:00
blr
[PATCH] powerpc: Fix handling of fpscr on 64-bit The recent merge of fpu.S broken the handling of fpscr for ARCH=powerpc and CONFIG_PPC64=y. FP registers could be corrupted, leading to strange random application crashes. The confusion arises, because the thread_struct has (and requires) a 64-bit area to save the fpscr, because we use load/store double instructions to get it in to/out of the FPU. However, only the low 32-bits are actually used, so we want to treat it as a 32-bit quantity when manipulating its bits to avoid extra load/stores on 32-bit. This patch replaces the current definition with a structure of two 32-bit quantities (pad and val), to clarify things as much as is possible. The 'val' field is used when manipulating bits, the structure itself is used when obtaining the address for loading/unloading the value from the FPU. While we're at it, consolidate the 4 (!) almost identical versions of cvt_fd() and cvt_df() (arch/ppc/kernel/misc.S, arch/ppc64/kernel/misc.S, arch/powerpc/kernel/misc_32.S, arch/powerpc/kernel/misc_64.S) into a single version in fpu.S. The new version takes a pointer to thread_struct and applies the correct offset itself, rather than a pointer to the fpscr field itself, again to avoid confusion as to which is the correct field to use. Finally, this patch makes ARCH=ppc64 also use the consolidated fpu.S code, which it previously did not. Built for G5 (ARCH=ppc64 and ARCH=powerpc), 32-bit powermac (ARCH=ppc and ARCH=powerpc) and Walnut (ARCH=ppc, CONFIG_MATH_EMULATION=y). Booted on G5 (ARCH=powerpc) and things which previously fell over no longer do. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-27 14:27:25 +08:00
/*
* These are used in the alignment trap handler when emulating
* single-precision loads and stores.
*/
_GLOBAL(cvt_fd)
lfs 0,0(r3)
stfd 0,0(r4)
blr
_GLOBAL(cvt_df)
lfd 0,0(r3)
stfs 0,0(r4)
blr