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| author |   Nick Piggin <nickpiggin@yahoo.com.au> | 2005-11-13 16:07:23 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-13 18:14:15 -0800 |
| commit | 53e86b91b7ae66d4c2757195cbd42e00d9199cf2 (patch) | |
| tree | 80c44aeb046ac91a5bc7465da91a7b2519c53096 /include/asm-i386 | |
| parent | [PATCH] rcutorture: renice to low priority (diff) | |
| download | linux-dev-53e86b91b7ae66d4c2757195cbd42e00d9199cf2.tar.xz linux-dev-53e86b91b7ae66d4c2757195cbd42e00d9199cf2.zip | |
[PATCH] i386: generic cmpxchg
- Make cmpxchg generally available on the i386 platform.
- Provide emulation of cmpxchg suitable for uniprocessor if built and run on
386.
From: Christoph Lameter <clameter@sgi.com>
- Cut down patch and small style changes.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-i386')
| -rw-r--r-- | include/asm-i386/system.h | 42 |
1 files changed, 39 insertions, 3 deletions
diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h index 97d52ac49e46..772f85da1206 100644 --- a/include/asm-i386/system.h +++ b/include/asm-i386/system.h @@ -263,6 +263,10 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz #ifdef CONFIG_X86_CMPXCHG #define __HAVE_ARCH_CMPXCHG 1 +#define cmpxchg(ptr,o,n)\ + ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\ + (unsigned long)(n),sizeof(*(ptr)))) +#endif static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) @@ -291,10 +295,42 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, return old; } -#define cmpxchg(ptr,o,n)\ - ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\ - (unsigned long)(n),sizeof(*(ptr)))) +#ifndef CONFIG_X86_CMPXCHG +/* + * Building a kernel capable running on 80386. It may be necessary to + * simulate the cmpxchg on the 80386 CPU. For that purpose we define + * a function for each of the sizes we support. + */ +extern unsigned long cmpxchg_386_u8(volatile void *, u8, u8); +extern unsigned long cmpxchg_386_u16(volatile void *, u16, u16); +extern unsigned long cmpxchg_386_u32(volatile void *, u32, u32); + +static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old, + unsigned long new, int size) +{ + switch (size) { + case 1: + return cmpxchg_386_u8(ptr, old, new); + case 2: + return cmpxchg_386_u16(ptr, old, new); + case 4: + return cmpxchg_386_u32(ptr, old, new); + } + return old; +} + +#define cmpxchg(ptr,o,n) \ +({ \ + __typeof__(*(ptr)) __ret; \ + if (likely(boot_cpu_data.x86 > 3)) \ + __ret = __cmpxchg((ptr), (unsigned long)(o), \ + (unsigned long)(n), sizeof(*(ptr))); \ + else \ + __ret = cmpxchg_386((ptr), (unsigned long)(o), \ + (unsigned long)(n), sizeof(*(ptr))); \ + __ret; \ +}) #endif #ifdef CONFIG_X86_CMPXCHG64 |