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authorAndi Kleen <ak@suse.de>2008-01-30 13:32:37 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:32:37 +0100
commit707fa8ed923b1b6a3d7af0d386b0b3abad28ed19 (patch)
tree181c7fe62e4c392486a06380df4da870bfaa40bf /include/asm-x86/cpufeature.h
parentde4218634e3df6d73a3e6cdfdf3a17fa3bc7e013 (diff)
x86: Implement support to synchronize RDTSC with LFENCE on Intel CPUs
According to Intel RDTSC can be always synchronized with LFENCE on all current CPUs. Implement the necessary CPUID bit for that. It is unclear yet if that is true for all future CPUs too, but if there's another way the kernel can be always updated. Cc: asit.k.mallick@intel.com Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/asm-x86/cpufeature.h')
-rw-r--r--include/asm-x86/cpufeature.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/asm-x86/cpufeature.h b/include/asm-x86/cpufeature.h
index 7d53eea8b94..c1a7e07859c 100644
--- a/include/asm-x86/cpufeature.h
+++ b/include/asm-x86/cpufeature.h
@@ -80,6 +80,7 @@
#define X86_FEATURE_SYNC_RDTSC (3*32+15) /* RDTSC synchronizes the CPU */
#define X86_FEATURE_REP_GOOD (3*32+16) /* rep microcode works well on this CPU */
#define X86_FEATURE_MFENCE_RDTSC (3*32+17) /* Mfence synchronizes RDTSC */
+#define X86_FEATURE_LFENCE_RDTSC (3*32+18) /* Lfence synchronizes RDTSC */
/* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
#define X86_FEATURE_XMM3 (4*32+ 0) /* Streaming SIMD Extensions-3 */