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authorNick Piggin <nickpiggin@yahoo.com.au>2005-11-13 19:07:23 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-13 21:14:15 -0500
commit53e86b91b7ae66d4c2757195cbd42e00d9199cf2 (patch)
tree80c44aeb046ac91a5bc7465da91a7b2519c53096 /include/asm-i386/system.h
parentdbdf65b1b7f8ec48bda1604cfea7ac09ce583d6b (diff)
[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/system.h')
-rw-r--r--include/asm-i386/system.h42
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
263 263
264#ifdef CONFIG_X86_CMPXCHG 264#ifdef CONFIG_X86_CMPXCHG
265#define __HAVE_ARCH_CMPXCHG 1 265#define __HAVE_ARCH_CMPXCHG 1
266#define cmpxchg(ptr,o,n)\
267 ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
268 (unsigned long)(n),sizeof(*(ptr))))
269#endif
266 270
267static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, 271static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
268 unsigned long new, int size) 272 unsigned long new, int size)
@@ -291,10 +295,42 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
291 return old; 295 return old;
292} 296}
293 297
294#define cmpxchg(ptr,o,n)\ 298#ifndef CONFIG_X86_CMPXCHG
295 ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\ 299/*
296 (unsigned long)(n),sizeof(*(ptr)))) 300 * Building a kernel capable running on 80386. It may be necessary to
301 * simulate the cmpxchg on the 80386 CPU. For that purpose we define
302 * a function for each of the sizes we support.
303 */
297 304
305extern unsigned long cmpxchg_386_u8(volatile void *, u8, u8);
306extern unsigned long cmpxchg_386_u16(volatile void *, u16, u16);
307extern unsigned long cmpxchg_386_u32(volatile void *, u32, u32);
308
309static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
310 unsigned long new, int size)
311{
312 switch (size) {
313 case 1:
314 return cmpxchg_386_u8(ptr, old, new);
315 case 2:
316 return cmpxchg_386_u16(ptr, old, new);
317 case 4:
318 return cmpxchg_386_u32(ptr, old, new);
319 }
320 return old;
321}
322
323#define cmpxchg(ptr,o,n) \
324({ \
325 __typeof__(*(ptr)) __ret; \
326 if (likely(boot_cpu_data.x86 > 3)) \
327 __ret = __cmpxchg((ptr), (unsigned long)(o), \
328 (unsigned long)(n), sizeof(*(ptr))); \
329 else \
330 __ret = cmpxchg_386((ptr), (unsigned long)(o), \
331 (unsigned long)(n), sizeof(*(ptr))); \
332 __ret; \
333})
298#endif 334#endif
299 335
300#ifdef CONFIG_X86_CMPXCHG64 336#ifdef CONFIG_X86_CMPXCHG64