diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2013-08-14 16:51:00 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-09-25 16:23:07 +0400 |
| commit | 1a338ac32ca630f67df25b4a16436cccc314e997 (patch) | |
| tree | 3291247c33c17376160821d19d1460c2da1da1a6 /arch/x86/include/asm/calling.h | |
| parent | c2daa3bed53a81171cf8c1a36db798e82b91afe8 (diff) | |
| download | linux-1a338ac32ca630f67df25b4a16436cccc314e997.tar.xz | |
sched, x86: Optimize the preempt_schedule() call
Remove the bloat of the C calling convention out of the
preempt_enable() sites by creating an ASM wrapper which allows us to
do an asm("call ___preempt_schedule") instead.
calling.h bits by Andi Kleen
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-tk7xdi1cvvxewixzke8t8le1@git.kernel.org
[ Fixed build error. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/calling.h')
| -rw-r--r-- | arch/x86/include/asm/calling.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/arch/x86/include/asm/calling.h b/arch/x86/include/asm/calling.h index 0fa675033912..cb4c73bfeb48 100644 --- a/arch/x86/include/asm/calling.h +++ b/arch/x86/include/asm/calling.h @@ -48,6 +48,8 @@ For 32-bit we have the following conventions - kernel is built with #include <asm/dwarf2.h> +#ifdef CONFIG_X86_64 + /* * 64-bit system call stack frame layout defines and helpers, * for assembly code: @@ -192,3 +194,51 @@ For 32-bit we have the following conventions - kernel is built with .macro icebp .byte 0xf1 .endm + +#else /* CONFIG_X86_64 */ + +/* + * For 32bit only simplified versions of SAVE_ALL/RESTORE_ALL. These + * are different from the entry_32.S versions in not changing the segment + * registers. So only suitable for in kernel use, not when transitioning + * from or to user space. The resulting stack frame is not a standard + * pt_regs frame. The main use case is calling C code from assembler + * when all the registers need to be preserved. + */ + + .macro SAVE_ALL + pushl_cfi %eax + CFI_REL_OFFSET eax, 0 + pushl_cfi %ebp + CFI_REL_OFFSET ebp, 0 + pushl_cfi %edi + CFI_REL_OFFSET edi, 0 + pushl_cfi %esi + CFI_REL_OFFSET esi, 0 + pushl_cfi %edx + CFI_REL_OFFSET edx, 0 + pushl_cfi %ecx + CFI_REL_OFFSET ecx, 0 + pushl_cfi %ebx + CFI_REL_OFFSET ebx, 0 + .endm + + .macro RESTORE_ALL + popl_cfi %ebx + CFI_RESTORE ebx + popl_cfi %ecx + CFI_RESTORE ecx + popl_cfi %edx + CFI_RESTORE edx + popl_cfi %esi + CFI_RESTORE esi + popl_cfi %edi + CFI_RESTORE edi + popl_cfi %ebp + CFI_RESTORE ebp + popl_cfi %eax + CFI_RESTORE eax + .endm + +#endif /* CONFIG_X86_64 */ + |