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SubjectRe: [PATCH 3/5] cpufreq: Add APERF/MPERF support for AMD processors
Date
On Monday 22 March 2010 19:38:39 Borislav Petkov wrote:
> From: Mark Langsdorf <mark.langsdorf@amd.com>
>
> Starting with model 10 of Family 0x10, AMD processors may have
> support for APERF/MPERF. Add support for identifying it and using
> it within cpufreq. Move the APERF/MPERF functions out of the
> acpi-cpufreq code and into their own file so they can easily be
> shared.
>
> Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com>
> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
> ---
> arch/x86/kernel/cpu/amd.c | 6 +++
> arch/x86/kernel/cpu/cpufreq/Makefile | 4 +-
> arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 44 +-----------------------
> arch/x86/kernel/cpu/cpufreq/mperf.c | 50 ++++++++++++++++++++++++++++
> arch/x86/kernel/cpu/cpufreq/mperf.h | 9 +++++
> arch/x86/kernel/cpu/cpufreq/powernow-k8.c | 8 ++++
> 6 files changed, 77 insertions(+), 44 deletions(-)
> create mode 100644 arch/x86/kernel/cpu/cpufreq/mperf.c
> create mode 100644 arch/x86/kernel/cpu/cpufreq/mperf.h
>
> diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> index e485825..796f662 100644
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -537,6 +537,12 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
> set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC);
> }
>
> + if (c->cpuid_level >= 6) {
> + unsigned ecx = cpuid_ecx(6);
> + if (ecx & 0x01)
> + set_cpu_cap(c, X86_FEATURE_APERFMPERF);
> + }
This is nearly identical to (beside c->cpuid_level > 6),
in arch/x86/kernel/cpu/intel.c:
if (c->cpuid_level > 6) {
unsigned ecx = cpuid_ecx(6);
if (ecx & 0x01)
set_cpu_cap(c, X86_FEATURE_APERFMPERF);
}
I expect you are correct... or could it get moved to general x86 init code?

Thomas


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