diff options
| author | Christoph Lameter <cl@linux.com> | 2011-03-26 20:57:18 -0500 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-27 19:25:36 -0700 |
| commit | d7c3f8cee81f4548de0513403b74131aee655576 (patch) | |
| tree | 3512188d9be3e429284d094d4bc1fdc2299b92db /arch/x86 | |
| parent | 76597cd31470fa130784c78fadb4dab2e624a723 (diff) | |
percpu: Omit segment prefix in the UP case for cmpxchg_double
Omit the segment prefix in the UP case. GS is not used then
and we will generate segfaults if cmpxchg16b is used otherwise.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/percpu.h | 10 | ||||
| -rw-r--r-- | arch/x86/lib/cmpxchg16b_emu.S | 14 |
2 files changed, 16 insertions, 8 deletions
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index a09e1f052d8..d475b4398d8 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -45,7 +45,7 @@ #include <linux/stringify.h> #ifdef CONFIG_SMP -#define __percpu_arg(x) "%%"__stringify(__percpu_seg)":%P" #x +#define __percpu_prefix "%%"__stringify(__percpu_seg)":" #define __my_cpu_offset percpu_read(this_cpu_off) /* @@ -62,9 +62,11 @@ (typeof(*(ptr)) __kernel __force *)tcp_ptr__; \ }) #else -#define __percpu_arg(x) "%P" #x +#define __percpu_prefix "" #endif +#define __percpu_arg(x) __percpu_prefix "%P" #x + /* * Initialized pointers to per-cpu variables needed for the boot * processor need to use these macros to get the proper address @@ -516,11 +518,11 @@ do { \ typeof(o2) __n2 = n2; \ typeof(o2) __dummy; \ alternative_io("call this_cpu_cmpxchg16b_emu\n\t" P6_NOP4, \ - "cmpxchg16b %%gs:(%%rsi)\n\tsetz %0\n\t", \ + "cmpxchg16b " __percpu_prefix "(%%rsi)\n\tsetz %0\n\t", \ X86_FEATURE_CX16, \ ASM_OUTPUT2("=a"(__ret), "=d"(__dummy)), \ "S" (&pcp1), "b"(__n1), "c"(__n2), \ - "a"(__o1), "d"(__o2)); \ + "a"(__o1), "d"(__o2) : "memory"); \ __ret; \ }) diff --git a/arch/x86/lib/cmpxchg16b_emu.S b/arch/x86/lib/cmpxchg16b_emu.S index 3e8b08a6de2..1e572c507d0 100644 --- a/arch/x86/lib/cmpxchg16b_emu.S +++ b/arch/x86/lib/cmpxchg16b_emu.S @@ -10,6 +10,12 @@ #include <asm/frame.h> #include <asm/dwarf2.h> +#ifdef CONFIG_SMP +#define SEG_PREFIX %gs: +#else +#define SEG_PREFIX +#endif + .text /* @@ -37,13 +43,13 @@ this_cpu_cmpxchg16b_emu: pushf cli - cmpq %gs:(%rsi), %rax + cmpq SEG_PREFIX(%rsi), %rax jne not_same - cmpq %gs:8(%rsi), %rdx + cmpq SEG_PREFIX 8(%rsi), %rdx jne not_same - movq %rbx, %gs:(%rsi) - movq %rcx, %gs:8(%rsi) + movq %rbx, SEG_PREFIX(%rsi) + movq %rcx, SEG_PREFIX 8(%rsi) popf mov $1, %al |