Messages in this thread Patch in this message | | | From | Xiaojian Du <> | Subject | [PATCH 1/2] x86/cpufeatures: Add AMD FAST CPPC feature flag | Date | Mon, 29 Apr 2024 15:03:21 +0800 |
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From: Perry Yuan <perry.yuan@amd.com>
Some AMD Zen 4 processors support a new feature FAST CPPC which allows for a faster CPPC loop due to internal architectual enhancements. The goal of this faster loop is higher performance at the same power consumption.
Reference: See the page 99 of PPR for AMD Family 19h Model 61h rev.B1, docID 56713
Signed-off-by: Perry Yuan <perry.yuan@amd.com> Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com> Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de> --- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/kernel/cpu/scattered.c | 1 + 2 files changed, 2 insertions(+)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 3c7434329661..6c128d463a14 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -470,6 +470,7 @@ #define X86_FEATURE_BHI_CTRL (21*32+ 2) /* "" BHI_DIS_S HW control available */ #define X86_FEATURE_CLEAR_BHB_HW (21*32+ 3) /* "" BHI_DIS_S HW control enabled */ #define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* "" Clear branch history at vmexit using SW loop */ +#define X86_FEATURE_FAST_CPPC (21*32 + 5) /* "" AMD Fast CPPC */ /* * BUG word(s) diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c index af5aa2c754c2..9c273c231f56 100644 --- a/arch/x86/kernel/cpu/scattered.c +++ b/arch/x86/kernel/cpu/scattered.c @@ -51,6 +51,7 @@ static const struct cpuid_bit cpuid_bits[] = { { X86_FEATURE_PERFMON_V2, CPUID_EAX, 0, 0x80000022, 0 }, { X86_FEATURE_AMD_LBR_V2, CPUID_EAX, 1, 0x80000022, 0 }, { X86_FEATURE_AMD_LBR_PMC_FREEZE, CPUID_EAX, 2, 0x80000022, 0 }, + { X86_FEATURE_FAST_CPPC, CPUID_EDX, 15, 0x80000007, 0 }, { 0, 0, 0, 0, 0 } }; -- 2.34.1
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