[PATCH] i386: i386 add X86_FEATURE_PEBS and detection
authorStephane Eranian <eranian@hpl.hp.com>
Thu, 7 Dec 2006 01:14:01 +0000 (02:14 +0100)
committerAndi Kleen <andi@basil.nowhere.org>
Thu, 7 Dec 2006 01:14:01 +0000 (02:14 +0100)
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 <eranian@hpl.hp.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
arch/i386/kernel/cpu/intel.c
include/asm-i386/cpufeature.h

index 94a95aa5227e8be03735f56a6ecd5c84638e2be7..798c2f617e8710d590c300c71f5836b8a282e154 100644 (file)
@@ -195,8 +195,14 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
        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)
 {
index 69ce35049a07e33ec566e95029d1c557130e5763..231672558c1fc3dda8f799faa080644235e1b8ad 100644 (file)
@@ -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 */
 #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 */