[PATCH 1/2] x86: Add support for Intel HWP feature detection.

From: dirk . brandewie
Date: Thu Nov 06 2014 - 12:41:33 EST


From: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>

Add support of Hardware Managed Performance States (HWP) described in Volume 3
section 14.4 of the SDM.

One bit CPUID.06H:EAX[bit 7] expresses the presence of the HWP feature on
the processor. The remaining bits CPUID.06H:EAX[bit 8-11] denote the
presense of various HWP features.

Cc: x86@xxxxxxxxxx
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
---
arch/x86/include/asm/cpufeature.h | 5 +++++
arch/x86/kernel/cpu/scattered.c | 5 +++++
2 files changed, 10 insertions(+)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 0bb1335..aede2c3 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -189,6 +189,11 @@
#define X86_FEATURE_DTHERM ( 7*32+ 7) /* Digital Thermal Sensor */
#define X86_FEATURE_HW_PSTATE ( 7*32+ 8) /* AMD HW-PState */
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
+#define X86_FEATURE_HWP ( 7*32+ 10) /* "hwp" Intel HWP */
+#define X86_FEATURE_HWP_NOITFY ( 7*32+ 11) /* Intel HWP_NOTIFY */
+#define X86_FEATURE_HWP_ACT_WINDOW ( 7*32+ 12) /* Intel HWP_ACT_WINDOW */
+#define X86_FEATURE_HWP_EPP ( 7*32+13) /* Intel HWP_EPP */
+#define X86_FEATURE_HWP_PKG_REQ ( 7*32+14) /* Intel HWP_PKG_REQ */

/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index 4a8013d..6063909 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -36,6 +36,11 @@ void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
{ X86_FEATURE_ARAT, CR_EAX, 2, 0x00000006, 0 },
{ X86_FEATURE_PLN, CR_EAX, 4, 0x00000006, 0 },
{ X86_FEATURE_PTS, CR_EAX, 6, 0x00000006, 0 },
+ { X86_FEATURE_HWP, CR_EAX, 7, 0x00000006, 0 },
+ { X86_FEATURE_HWP_NOITFY, CR_EAX, 8, 0x00000006, 0 },
+ { X86_FEATURE_HWP_ACT_WINDOW, CR_EAX, 9, 0x00000006, 0 },
+ { X86_FEATURE_HWP_EPP, CR_EAX,10, 0x00000006, 0 },
+ { X86_FEATURE_HWP_PKG_REQ, CR_EAX,11, 0x00000006, 0 },
{ X86_FEATURE_APERFMPERF, CR_ECX, 0, 0x00000006, 0 },
{ X86_FEATURE_EPB, CR_ECX, 3, 0x00000006, 0 },
{ X86_FEATURE_HW_PSTATE, CR_EDX, 7, 0x80000007, 0 },
--
1.9.3

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