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x86/cpufeatures: Add PerfMonV2 feature bit 

CPUID leaf 0x80000022 i.e. ExtPerfMonAndDbg advertises some
new performance monitoring features for AMD processors.

Bit 0 of EAX indicates support for Performance Monitoring
Version 2 (PerfMonV2) features. If found to be set during
PMU initialization, the EBX bits of the same CPUID function
can be used to determine the number of available PMCs for
different PMU types. Additionally, Core PMCs can be managed
using new global control and status registers.

For better utilization of feature words, PerfMonV2 is added
as a scattered feature bit.

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/c70e497e22f18e7f05b025bb64ca21cc12b17792.1650515382.git.sandipan.das@amd.com
This commit is contained in:
Sandipan Das 2022-04-21 11:16:53 +05:30 committed by Peter Zijlstra
parent 78ed93d72d
commit d6d0c7f681
2 changed files with 2 additions and 1 deletions
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2
arch/x86/include/asm/cpufeatures.h
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@ -211,7 +211,7 @@
#define X86_FEATURE_SSBD ( 7*32+17) /* Speculative Store Bypass Disable */
#define X86_FEATURE_MBA ( 7*32+18) /* Memory Bandwidth Allocation */
#define X86_FEATURE_RSB_CTXSW ( 7*32+19) /* "" Fill RSB on context switches */
/* FREE! ( 7*32+20) */
#define X86_FEATURE_PERFMON_V2 ( 7*32+20) /* AMD Performance Monitoring Version 2 */
#define X86_FEATURE_USE_IBPB ( 7*32+21) /* "" Indirect Branch Prediction Barrier enabled */
#define X86_FEATURE_USE_IBRS_FW ( 7*32+22) /* "" Use IBRS during runtime firmware calls */
#define X86_FEATURE_SPEC_STORE_BYPASS_DISABLE ( 7*32+23) /* "" Disable Speculative Store Bypass. */

1
arch/x86/kernel/cpu/scattered.c
View File

@ -43,6 +43,7 @@ static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 },
{ X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
{ X86_FEATURE_MBA, CPUID_EBX, 6, 0x80000008, 0 },
{ X86_FEATURE_PERFMON_V2, CPUID_EAX, 0, 0x80000022, 0 },
{ 0, 0, 0, 0, 0 }
};