From: Stephane Eranian Here is a patch (used by perfmon2) to detect the presence of the Precise Event Based Sampling (PEBS) feature for i386. The patch also adds the cpu_has_pebs macro. - adds X86_FEATURE_PEBS - adds cpu_has_pebs to test for X86_FEATURE_PEBS Signed-off-by: stephane eranian Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/kernel/cpu/intel.c | 8 +++++++- include/asm-i386/cpufeature.h | 2 ++ 2 files changed, 9 insertions(+), 1 deletion(-) diff -puN arch/i386/kernel/cpu/intel.c~i386-add-x86_feature_pebs-and-detection arch/i386/kernel/cpu/intel.c --- a/arch/i386/kernel/cpu/intel.c~i386-add-x86_feature_pebs-and-detection +++ a/arch/i386/kernel/cpu/intel.c @@ -195,8 +195,14 @@ static void __cpuinit init_intel(struct if ((c->x86 == 0xf && c->x86_model >= 0x03) || (c->x86 == 0x6 && c->x86_model >= 0x0e)) set_bit(X86_FEATURE_CONSTANT_TSC, c->x86_capability); -} + if (cpu_has_ds) { + unsigned int l1; + rdmsr(MSR_IA32_MISC_ENABLE, l1, l2); + if (!(l1 & (1<<12))) + set_bit(X86_FEATURE_PEBS, c->x86_capability); + } +} static unsigned int __cpuinit intel_size_cache(struct cpuinfo_x86 * c, unsigned int size) { diff -puN include/asm-i386/cpufeature.h~i386-add-x86_feature_pebs-and-detection include/asm-i386/cpufeature.h --- a/include/asm-i386/cpufeature.h~i386-add-x86_feature_pebs-and-detection +++ a/include/asm-i386/cpufeature.h @@ -73,6 +73,7 @@ #define X86_FEATURE_UP (3*32+ 9) /* smp kernel running on up */ #define X86_FEATURE_FXSAVE_LEAK (3*32+10) /* FXSAVE leaks FOP/FIP/FOP */ #define X86_FEATURE_ARCH_PERFMON (3*32+11) /* Intel Architectural PerfMon */ +#define X86_FEATURE_PEBS (3*32+12) /* Precise-Event Based Sampling */ /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */ #define X86_FEATURE_XMM3 (4*32+ 0) /* Streaming SIMD Extensions-3 */ @@ -135,6 +136,7 @@ #define cpu_has_pmm boot_cpu_has(X86_FEATURE_PMM) #define cpu_has_pmm_enabled boot_cpu_has(X86_FEATURE_PMM_EN) #define cpu_has_ds boot_cpu_has(X86_FEATURE_DS) +#define cpu_has_pebs boot_cpu_has(X86_FEATURE_PEBS) #endif /* __ASM_I386_CPUFEATURE_H */ _