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[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>
This commit is contained in:
Stephane Eranian 2006-12-07 02:14:01 +01:00 committed by Andi Kleen
parent bd1d599518
commit 36b2a8d5af
2 changed files with 9 additions and 0 deletions
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7
arch/x86_64/kernel/setup.c
View File

@ -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);

2
include/asm-x86_64/cpufeature.h
View File

@ -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 */