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authorStephane Eranian <eranian@hpl.hp.com>2006-12-07 02:14:01 +0100
committerAndi Kleen <andi@basil.nowhere.org>2006-12-07 02:14:01 +0100
commit36b2a8d5aff4cb3ee83d5e40447a8f073bcfe2fb (patch)
treea7883c46dcc89ac79474ff4717ec923043adfd2f
parentbd1d599518bf11992cc6d5b0df08da4a2b7b0db5 (diff)
[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 <eranian@hpl.hp.com> Signed-off-by: Andi Kleen <ak@suse.de>
-rw-r--r--arch/x86_64/kernel/setup.c7
-rw-r--r--include/asm-x86_64/cpufeature.h2
2 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index fc944b5e8f4..619af2e2fa2 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 65eb39e8f3c..d280384807e 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 */