On Thu, Oct 03, 2024 at 04:37:58PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <perry.yuan@xxxxxxx>
>
> CPUID leaf 0x80000026 advertises core types with different efficiency
> rankings.
>
> Bit 30 indicates the heterogeneous core topology feature, if the bit
> set, it means not all instances at the current hierarchical level have
> the same core topology.
>
> This is described in the AMD64 Architecture Programmers Manual Volume
> 2 and 3, doc ID #25493 and #25494.
>
> Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx>
> Co-developed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
> 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 dd4682857c12..cea1ed82aeb4 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -473,6 +473,7 @@
> #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 */
> +#define X86_FEATURE_HETERO_CORE_TOPOLOGY (21*32 + 6) /* Heterogeneous Core Topology */
So this is an AMD-specific feature bit and so it should have "AMD" in the
name:
#define X86_FEATURE_AMD_HETERO_CORE_TOPOLOGY (21*32 + 6) /* Heterogeneous Core Topology */
Also, as clarified offlist, please do not take x86 patches without an Ack at
least through some other tree.
> diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
> index c84c30188fdf..3bba55323163 100644
> --- a/arch/x86/kernel/cpu/scattered.c
> +++ b/arch/x86/kernel/cpu/scattered.c
> @@ -52,6 +52,7 @@ 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_HETERO_CORE_TOPOLOGY, CPUID_EAX, 30, 0x80000026, 0 },
So my APM calls this bit: "HeterogeneousCores".
Why aren't you calling it this?
IOW: X86_FEATURE_AMD_HETEROGENEOUS_CORES
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
