p71924506
/
linux_old1
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

x86/asm/entry/64: Save all regs on interrupt entry 

To prepare for the big rewrite of the error and interrupt exit
paths, we will need pt_regs completely filled in.

It's already completely filled in when error_exit runs, so rearrange
interrupt handling to match it.  This will slow down interrupt
handling very slightly (eight instructions), but the
simplification it enables will be more than worth it.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/d8a766a7f558b30e6e01352854628a2d9943460c.1435952415.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2015-07-03 12:44:29 -07:00 committed by Ingo Molnar
parent 29ea1b258b
commit ff467594f2
2 changed files with 9 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/entry/calling.h
View File

@ -135,9 +135,6 @@ For 32-bit we have the following conventions - kernel is built with
movq %rbp, 4*8+\offset(%rsp)
movq %rbx, 5*8+\offset(%rsp)
.endm
.macro SAVE_EXTRA_REGS_RBP offset=0
movq %rbp, 4*8+\offset(%rsp)
.endm
.macro RESTORE_EXTRA_REGS offset=0
movq 0*8+\offset(%rsp), %r15

29
arch/x86/entry/entry_64.S
View File

@ -502,21 +502,13 @@ END(irq_entries_start)
/* 0(%rsp): ~(interrupt number) */
.macro interrupt func
cld
/*
* Since nothing in interrupt handling code touches r12...r15 members
* of "struct pt_regs", and since interrupts can nest, we can save
* four stack slots and simultaneously provide
* an unwind-friendly stack layout by saving "truncated" pt_regs
* exactly up to rbp slot, without these members.
*/
ALLOC_PT_GPREGS_ON_STACK -RBP
SAVE_C_REGS -RBP
/* this goes to 0(%rsp) for unwinder, not for saving the value: */
SAVE_EXTRA_REGS_RBP -RBP
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
SAVE_EXTRA_REGS
leaq -RBP(%rsp), %rdi /* arg1 for \func (pointer to pt_regs) */
movq %rsp,%rdi /* arg1 for \func (pointer to pt_regs) */
testb $3, CS-RBP(%rsp)
testb $3, CS(%rsp)
jz 1f
SWAPGS
1:
@ -553,9 +545,7 @@ ret_from_intr:
decl PER_CPU_VAR(irq_count)
/* Restore saved previous stack */
popq %rsi
/* return code expects complete pt_regs - adjust rsp accordingly: */
leaq -RBP(%rsi), %rsp
popq %rsp
testb $3, CS(%rsp)
jz retint_kernel
@ -580,7 +570,7 @@ retint_swapgs: /* return to user-space */
TRACE_IRQS_IRETQ
SWAPGS
jmp restore_c_regs_and_iret
jmp restore_regs_and_iret
/* Returning to kernel space */
retint_kernel:
@ -604,6 +594,8 @@ retint_kernel:
* At this label, code paths which return to kernel and to user,
* which come from interrupts/exception and from syscalls, merge.
*/
restore_regs_and_iret:
RESTORE_EXTRA_REGS
restore_c_regs_and_iret:
RESTORE_C_REGS
REMOVE_PT_GPREGS_FROM_STACK 8
@ -674,12 +666,10 @@ retint_signal:
jz retint_swapgs
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
SAVE_EXTRA_REGS
movq $-1, ORIG_RAX(%rsp)
xorl %esi, %esi /* oldset */
movq %rsp, %rdi /* &pt_regs */
call do_notify_resume
RESTORE_EXTRA_REGS
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
GET_THREAD_INFO(%rcx)
@ -1160,7 +1150,6 @@ END(error_entry)
*/
ENTRY(error_exit)
movl %ebx, %eax
RESTORE_EXTRA_REGS
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
testl %eax, %eax