diff options
| author | H. Peter Anvin <hpa@linux.intel.com> | 2010-07-29 04:05:11 +0400 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2010-07-29 04:05:11 +0400 |
| commit | a378d9338e8dde78314b3a6ae003de351936c729 (patch) | |
| tree | 1f0c947c4c55bbb98c129a260ac604f6b39526ac /arch | |
| parent | 90c8f92f5c807807ca74d5f2f313794925174e6b (diff) | |
| download | linux-a378d9338e8dde78314b3a6ae003de351936c729.tar.xz | |
x86, asm: Merge cmpxchg_486_u64() and cmpxchg8b_emu()
We have two functions for doing exactly the same thing -- emulating
cmpxchg8b on 486 and older hardware -- with different calling
conventions, and yet doing the same thing. Drop the C version and use
the assembly version, via alternatives, for both the local and
non-local versions of cmpxchg8b.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <AANLkTikAmaDPji-TVDarmG1yD=fwbffcsmEU=YEuP+8r@mail.gmail.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/cmpxchg_32.h | 30 | ||||
| -rw-r--r-- | arch/x86/lib/cmpxchg.c | 18 |
2 files changed, 14 insertions, 34 deletions
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h index f5bd1fd388ff..284a6e8f7ce1 100644 --- a/arch/x86/include/asm/cmpxchg_32.h +++ b/arch/x86/include/asm/cmpxchg_32.h @@ -246,8 +246,6 @@ static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old, * to simulate the cmpxchg8b on the 80386 and 80486 CPU. */ -extern unsigned long long cmpxchg_486_u64(volatile void *, u64, u64); - #define cmpxchg64(ptr, o, n) \ ({ \ __typeof__(*(ptr)) __ret; \ @@ -265,20 +263,20 @@ extern unsigned long long cmpxchg_486_u64(volatile void *, u64, u64); __ret; }) - -#define cmpxchg64_local(ptr, o, n) \ -({ \ - __typeof__(*(ptr)) __ret; \ - if (likely(boot_cpu_data.x86 > 4)) \ - __ret = (__typeof__(*(ptr)))__cmpxchg64_local((ptr), \ - (unsigned long long)(o), \ - (unsigned long long)(n)); \ - else \ - __ret = (__typeof__(*(ptr)))cmpxchg_486_u64((ptr), \ - (unsigned long long)(o), \ - (unsigned long long)(n)); \ - __ret; \ -}) +#define cmpxchg64_local(ptr, o, n) \ +({ \ + __typeof__(*(ptr)) __ret; \ + __typeof__(*(ptr)) __old = (o); \ + __typeof__(*(ptr)) __new = (n); \ + alternative_io("call cmpxchg8b_emu", \ + "cmpxchg8b (%%esi)" , \ + X86_FEATURE_CX8, \ + "=A" (__ret), \ + "S" ((ptr)), "0" (__old), \ + "b" ((unsigned int)__new), \ + "c" ((unsigned int)(__new>>32)) \ + : "memory"); \ + __ret; }) #endif diff --git a/arch/x86/lib/cmpxchg.c b/arch/x86/lib/cmpxchg.c index 2056ccf572cc..5d619f6df3ee 100644 --- a/arch/x86/lib/cmpxchg.c +++ b/arch/x86/lib/cmpxchg.c @@ -52,21 +52,3 @@ unsigned long cmpxchg_386_u32(volatile void *ptr, u32 old, u32 new) } EXPORT_SYMBOL(cmpxchg_386_u32); #endif - -#ifndef CONFIG_X86_CMPXCHG64 -unsigned long long cmpxchg_486_u64(volatile void *ptr, u64 old, u64 new) -{ - u64 prev; - unsigned long flags; - - /* Poor man's cmpxchg8b for 386 and 486. Unsuitable for SMP */ - local_irq_save(flags); - prev = *(u64 *)ptr; - if (prev == old) - *(u64 *)ptr = new; - local_irq_restore(flags); - return prev; -} -EXPORT_SYMBOL(cmpxchg_486_u64); -#endif - |