Messages in this thread Patch in this message | | | From | Jeremy Fitzhardinge <> | Subject | [PATCH 07/15] x86: add xadd helper macro | Date | Mon, 22 Aug 2011 16:15:03 -0700 |
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From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Add a common xadd implementation.
This has the side effect of generating a bad instruction if you try to use it on a 64-bit value on a 32-bit system - but don't do that.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> --- arch/x86/include/asm/cmpxchg.h | 32 ++++++++++++++++++++++++++++++++ 1 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h index a460fa0..b771cdb 100644 --- a/arch/x86/include/asm/cmpxchg.h +++ b/arch/x86/include/asm/cmpxchg.h @@ -1,5 +1,37 @@ +#ifndef ASM_X86_CMPXCHG_H +#define ASM_X86_CMPXCHG_H + #ifdef CONFIG_X86_32 # include "cmpxchg_32.h" #else # include "cmpxchg_64.h" #endif + + +#define xadd(ptr, inc) \ + do { \ + switch (sizeof(*(ptr))) { \ + case 1: \ + asm volatile (LOCK_PREFIX "xaddb %b0, %1\n" \ + : "+r" (inc), "+m" (*(ptr)) \ + : : "memory", "cc"); \ + break; \ + case 2: \ + asm volatile (LOCK_PREFIX "xaddw %w0, %1\n" \ + : "+r" (inc), "+m" (*(ptr)) \ + : : "memory", "cc"); \ + break; \ + case 4: \ + asm volatile (LOCK_PREFIX "xaddl %0, %1\n" \ + : "+r" (inc), "+m" (*(ptr)) \ + : : "memory", "cc"); \ + break; \ + case 8: \ + asm volatile (LOCK_PREFIX "xaddq %q0, %1\n" \ + : "+r" (inc), "+m" (*(ptr)) \ + : : "memory", "cc"); \ + break; \ + } \ + } while(0) + +#endif /* ASM_X86_CMPXCHG_H */ -- 1.7.6
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