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| author |   Jan Beulich <JBeulich@novell.com> | 2005-10-30 14:59:27 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-30 17:37:11 -0800 |
| commit | 8896fab35e62aa748a5ce62ac773508e51f10be1 (patch) | |
| tree | bb8f2dce7b5d0aa6ffe68aa6b97920d2ce32e164 /include/asm-i386 | |
| parent | [PATCH] i386 and x86_64 TSC set_cyc2ns_scale imprecision (diff) | |
| download | linux-dev-8896fab35e62aa748a5ce62ac773508e51f10be1.tar.xz linux-dev-8896fab35e62aa748a5ce62ac773508e51f10be1.zip | |
[PATCH] x86: cmpxchg improvements
This adjusts i386's cmpxchg patterns so that
- for word and long cmpxchg-es the compiler can utilize all possible
registers
- cmpxchg8b gets disabled when the minimum specified hardware architectur
doesn't support it (like was already happening for the byte, word, and
long ones).
Signed-off-by: Jan Beulich <jbeulich@novell.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 | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h index acd5c26b69ba..97d52ac49e46 100644 --- a/include/asm-i386/system.h +++ b/include/asm-i386/system.h @@ -167,6 +167,8 @@ struct __xchg_dummy { unsigned long a[100]; }; #define __xg(x) ((struct __xchg_dummy *)(x)) +#ifdef CONFIG_X86_CMPXCHG64 + /* * The semantics of XCHGCMP8B are a bit strange, this is why * there is a loop and the loading of %%eax and %%edx has to @@ -221,6 +223,8 @@ static inline void __set_64bit_var (unsigned long long *ptr, __set_64bit(ptr, (unsigned int)(value), (unsigned int)((value)>>32ULL) ) : \ __set_64bit(ptr, ll_low(value), ll_high(value)) ) +#endif + /* * Note: no "lock" prefix even on SMP: xchg always implies lock anyway * Note 2: xchg has side effect, so that attribute volatile is necessary, @@ -259,7 +263,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz #ifdef CONFIG_X86_CMPXCHG #define __HAVE_ARCH_CMPXCHG 1 -#endif static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) @@ -275,13 +278,13 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, case 2: __asm__ __volatile__(LOCK_PREFIX "cmpxchgw %w1,%2" : "=a"(prev) - : "q"(new), "m"(*__xg(ptr)), "0"(old) + : "r"(new), "m"(*__xg(ptr)), "0"(old) : "memory"); return prev; case 4: __asm__ __volatile__(LOCK_PREFIX "cmpxchgl %1,%2" : "=a"(prev) - : "q"(new), "m"(*__xg(ptr)), "0"(old) + : "r"(new), "m"(*__xg(ptr)), "0"(old) : "memory"); return prev; } @@ -291,6 +294,30 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, #define cmpxchg(ptr,o,n)\ ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\ (unsigned long)(n),sizeof(*(ptr)))) + +#endif + +#ifdef CONFIG_X86_CMPXCHG64 + +static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long long old, + unsigned long long new) +{ + unsigned long long prev; + __asm__ __volatile__(LOCK_PREFIX "cmpxchg8b %3" + : "=A"(prev) + : "b"((unsigned long)new), + "c"((unsigned long)(new >> 32)), + "m"(*__xg(ptr)), + "0"(old) + : "memory"); + return prev; +} + +#define cmpxchg64(ptr,o,n)\ + ((__typeof__(*(ptr)))__cmpxchg64((ptr),(unsigned long long)(o),\ + (unsigned long long)(n))) + +#endif #ifdef __KERNEL__ struct alt_instr { |