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| author | Christoph Lameter <cl@linux.com> | 2011-06-01 21:25:47 +0400 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2011-06-25 23:17:32 +0400 |
| commit | 3824abd1279ef75f791c43a6b1e3162ae0692b42 (patch) | |
| tree | f8ca989ec654a9f5cffc28eca7acb4e8a5389814 /arch/x86/include/asm/cpufeature.h | |
| parent | 56299378726d5f2ba8d3c8cbbd13cb280ba45e4f (diff) | |
| download | linux-3824abd1279ef75f791c43a6b1e3162ae0692b42.tar.xz | |
x86: Add support for cmpxchg_double
A simple implementation that only supports the word size and does not
have a fallback mode (would require a spinlock).
Add 32 and 64 bit support for cmpxchg_double. cmpxchg double uses
the cmpxchg8b or cmpxchg16b instruction on x86 processors to compare
and swap 2 machine words. This allows lockless algorithms to move more
context information through critical sections.
Set a flag CONFIG_CMPXCHG_DOUBLE to signal that support for double word
cmpxchg detection has been build into the kernel. Note that each subsystem
using cmpxchg_double has to implement a fall back mechanism as long as
we offer support for processors that do not implement cmpxchg_double.
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Christoph Lameter <cl@linux.com>
Link: http://lkml.kernel.org/r/20110601172614.173427964@linux.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/include/asm/cpufeature.h')
| -rw-r--r-- | arch/x86/include/asm/cpufeature.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 71cc3800712c..d1053cd6f896 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -288,6 +288,8 @@ extern const char * const x86_power_flags[32]; #define cpu_has_hypervisor boot_cpu_has(X86_FEATURE_HYPERVISOR) #define cpu_has_pclmulqdq boot_cpu_has(X86_FEATURE_PCLMULQDQ) #define cpu_has_perfctr_core boot_cpu_has(X86_FEATURE_PERFCTR_CORE) +#define cpu_has_cx8 boot_cpu_has(X86_FEATURE_CX8) +#define cpu_has_cx16 boot_cpu_has(X86_FEATURE_CX16) #if defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_64) # define cpu_has_invlpg 1 |