From 36b2a8d5aff4cb3ee83d5e40447a8f073bcfe2fb Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Thu, 7 Dec 2006 02:14:01 +0100 Subject: [PATCH] [PATCH] x86-64: add X86_FEATURE_PEBS and detection Here is a patch (used by perfmon2) to detect the presence of the Precise Event Based Sampling (PEBS) feature for Intel 64-bit processors. The patch also adds the cpu_has_pebs macro. changelog: - adds X86_FEATURE_PEBS - adds cpu_has_pebs to test for X86_FEATURE_PEBS Signed-off-by: stephane eranian Signed-off-by: Andi Kleen --- arch/x86_64/kernel/setup.c | 7 +++++++ include/asm-x86_64/cpufeature.h | 2 ++ 2 files changed, 9 insertions(+) diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c index fc944b5e8f4a..619af2e2fa26 100644 --- a/arch/x86_64/kernel/setup.c +++ b/arch/x86_64/kernel/setup.c @@ -835,6 +835,13 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c) set_bit(X86_FEATURE_ARCH_PERFMON, &c->x86_capability); } + if (cpu_has_ds) { + unsigned int l1, l2; + rdmsr(MSR_IA32_MISC_ENABLE, l1, l2); + if (!(l1 & (1<<12))) + set_bit(X86_FEATURE_PEBS, c->x86_capability); + } + n = c->extended_cpuid_level; if (n >= 0x80000008) { unsigned eax = cpuid_eax(0x80000008); diff --git a/include/asm-x86_64/cpufeature.h b/include/asm-x86_64/cpufeature.h index 65eb39e8f3cc..d280384807ef 100644 --- a/include/asm-x86_64/cpufeature.h +++ b/include/asm-x86_64/cpufeature.h @@ -68,6 +68,7 @@ #define X86_FEATURE_FXSAVE_LEAK (3*32+7) /* FIP/FOP/FDP leaks through FXSAVE */ #define X86_FEATURE_UP (3*32+8) /* SMP kernel running on UP */ #define X86_FEATURE_ARCH_PERFMON (3*32+9) /* Intel Architectural PerfMon */ +#define X86_FEATURE_PEBS (3*32+10) /* 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 */ @@ -113,5 +114,6 @@ #define cpu_has_centaur_mcr 0 #define cpu_has_clflush boot_cpu_has(X86_FEATURE_CLFLSH) #define cpu_has_ds boot_cpu_has(X86_FEATURE_DS) +#define cpu_has_pebs boot_cpu_has(X86_FEATURE_PEBS) #endif /* __ASM_X8664_CPUFEATURE_H */ -- 2.30.2