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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 /arch/x86/kernel/cpu
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 'arch/x86/kernel/cpu')
-rw-r--r--arch/x86/kernel/cpu/intel.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index e4b7e73e902..0a4abdb61ae 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -203,9 +203,10 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
}
#endif
+ if (cpu_has_xmm)
+ set_bit(X86_FEATURE_LFENCE_RDTSC, c->x86_capability);
if (c->x86 == 15) {
set_bit(X86_FEATURE_P4, c->x86_capability);
- set_bit(X86_FEATURE_SYNC_RDTSC, c->x86_capability);
}
if (c->x86 == 6)
set_bit(X86_FEATURE_P3, c->x86_capability);