From: Xiaojian Du <Xiaojian.Du@amd.com>
To: <linux-pm@vger.kernel.org>, <gautham.shenoy@amd.com>,
<Borislav.Petkov@amd.com>, <mario.limonciello@amd.com>,
<ray.huang@amd.com>
Cc: <Perry.Yuan@amd.com>, Perry Yuan <perry.yuan@amd.com>,
Xiaojian Du <Xiaojian.Du@amd.com>
Subject: [PATCH 1/2] x86/cpufeatures: Add AMD FAST CPPC feature flag
Date: Sun, 28 Apr 2024 17:11:32 +0800 [thread overview]
Message-ID: <20240428091133.592333-1-Xiaojian.Du@amd.com> (raw)
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:
Page 99 of PPR for AMD Family 19h Model 61h rev.B1
https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/programmer-references/56713-B1_3_05.zip
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com>
---
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
next reply other threads:[~2024-04-28 9:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-28 9:11 Xiaojian Du [this message]
2024-04-28 9:11 ` [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay for some models Xiaojian Du
2024-04-28 9:54 ` [PATCH 1/2] x86/cpufeatures: Add AMD FAST CPPC feature flag Borislav Petkov
2024-04-28 10:59 ` Du, Xiaojian
2024-04-28 11:05 ` Borislav Petkov
2024-04-29 7:03 Xiaojian Du
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