[PATCH] X86: Introduce HW-Pstate scattered cpuid feature

From: Thomas Renninger
Date: Thu Dec 22 2011 - 12:55:19 EST


On Thursday, December 22, 2011 01:14:41 AM Andi Kleen wrote:
> > So this should be:
> >
> > 1. added to the scattered CPUID features list;
> > 2. artificially set in the AMD-specific initialization code for the
> > older CPUs.
>
> Not sure (2) is correct. As far as I understand it's actually different
> mechanisms, just implemented by the same driver.
>
> Keeping the list for old CPUs is not a big issue anyways.
>
> Agreed with (1)

This would be the hw-pstate feature patch to avoid
mainting families for autoloading, etc.

It should be in powernow-k8 then:
/* IO-Based switching */
{ X86_VENDOR_AMD, 0xf, },
/* Future models support MSR based switching and a cpuid bit for it */
{ X86_VENDOR_AMD, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_HW_PSTATE },

Something does not work and I need to re-test and dig.
I'll embed this one into the others from Andi and will resend the next days.

Thomas

---
X86: Introduce HW-Pstate scattered cpuid feature

It is rather similar to CPB (boot capability) feature
and exists since fam10h (can be looked up in AMD's BKDG).

Signed-off-by: Thomas Renninger <trenn@xxxxxxx>

---
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/kernel/cpu/scattered.c | 1 +
2 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index f3444f7..7a1003d 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -176,6 +176,7 @@
#define X86_FEATURE_PLN (7*32+ 5) /* Intel Power Limit Notification */
#define X86_FEATURE_PTS (7*32+ 6) /* Intel Package Thermal Status */
#define X86_FEATURE_DTS (7*32+ 7) /* Digital Thermal Sensor */
+#define X86_FEATURE_HW_PSTATE (7*32+ 8) /* AMD HW-PState */

/* 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 c7f64e6..addf9e8 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -40,6 +40,7 @@ void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
{ X86_FEATURE_EPB, CR_ECX, 3, 0x00000006, 0 },
{ X86_FEATURE_XSAVEOPT, CR_EAX, 0, 0x0000000d, 1 },
{ X86_FEATURE_CPB, CR_EDX, 9, 0x80000007, 0 },
+ { X86_FEATURE_HW_PSTATE, CR_EDX, 7, 0x80000007, 0 },
{ X86_FEATURE_NPT, CR_EDX, 0, 0x8000000a, 0 },
{ X86_FEATURE_LBRV, CR_EDX, 1, 0x8000000a, 0 },
{ X86_FEATURE_SVML, CR_EDX, 2, 0x8000000a, 0 },
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