From: Borislav Petkov <borislav.petkov@xxxxxxx>
By semi-popular demand, this adds the Core Performance Boost feature
flag to /proc/cpuinfo. Possible use case for this is userspace tools
like cpufreq-aperf, for example, so that they don't have to jump through
hoops of accessing "/dev/cpu/%d/cpuid" in order to check for CPB hw
support, or call cpuid from userspace.
Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx>
Reviewed-by: Thomas Renninger <trenn@xxxxxxx>
---
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/kernel/cpu/addon_cpuid_features.c | 5 +++--
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 0cd82d0..630e623 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -161,6 +161,7 @@
*/
#define X86_FEATURE_IDA (7*32+ 0) /* Intel Dynamic Acceleration */
#define X86_FEATURE_ARAT (7*32+ 1) /* Always Running APIC Timer */
+#define X86_FEATURE_CPB (7*32+ 2) /* AMD Core Performance Boost */
/* Virtualization flags: Linux defined */
#define X86_FEATURE_TPR_SHADOW (8*32+ 0) /* Intel TPR Shadow */
diff --git a/arch/x86/kernel/cpu/addon_cpuid_features.c b/arch/x86/kernel/cpu/addon_cpuid_features.c
index 97ad79c..ead2a1c 100644
--- a/arch/x86/kernel/cpu/addon_cpuid_features.c
+++ b/arch/x86/kernel/cpu/addon_cpuid_features.c
@@ -30,8 +30,9 @@ void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
const struct cpuid_bit *cb;
static const struct cpuid_bit __cpuinitconst cpuid_bits[] = {
- { X86_FEATURE_IDA, CR_EAX, 1, 0x00000006 },
- { X86_FEATURE_ARAT, CR_EAX, 2, 0x00000006 },
+ { X86_FEATURE_IDA, CR_EAX, 1, 0x00000006 },
+ { X86_FEATURE_ARAT, CR_EAX, 2, 0x00000006 },
+ { X86_FEATURE_CPB, CR_EDX, 9, 0x80000007 },
{ X86_FEATURE_NPT, CR_EDX, 0, 0x8000000a },
{ X86_FEATURE_LBRV, CR_EDX, 1, 0x8000000a },
{ X86_FEATURE_SVML, CR_EDX, 2, 0x8000000a },
--
1.7.0
--
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