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SubjectRe: [PATCH 1/2] x86/intel: introduce platform_id
On Mon, Jan 15, 2018 at 01:43:22PM +0800, Jia Zhang wrote:
> Platform ID retrieved from MSR_IA32_PLATFORM_ID may be used as
> a filtration condition in some cases.
>
> Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com>
> ---
> arch/x86/include/asm/processor.h | 1 +
> arch/x86/kernel/cpu/intel.c | 7 +++++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index d3a67fb..c0b4d47 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -133,6 +133,7 @@ struct cpuinfo_x86 {
> u16 cpu_index;
> u32 microcode;
> unsigned initialized : 1;
> + u8 platform_id;

Platform ID in cpuinfo?

Nope, I don't think so.

> } __randomize_layout;
>
> struct cpuid_regs {
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index b1af220..cee0554 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -229,6 +229,13 @@ static void early_init_intel(struct cpuinfo_x86 *c)
> }
>
> check_mpx_erratum(c);
> +
> + if ((c->x86 > 6) || (c->x86_model >= 5)) {
> + u32 val[2];
> +
> + rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
> + c->platform_id = 1 << ((val[1] >> 18) & 7);
> + }

collect_cpu_info() in arch/x86/kernel/cpu/microcode/intel.c already does
that so you already have that info without duplicating it.

--
Regards/Gruss,
Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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