Re: [PATCH 2/4] x86, CPU: Extend TLB size detection for AMD

From: H. Peter Anvin
Date: Fri Aug 03 2012 - 14:33:10 EST


On 08/03/2012 09:37 AM, Borislav Petkov wrote:
> From: Borislav Petkov <borislav.petkov@xxxxxxx>
>
> TLB characteristics on AMD are in the extended CPUID level, leafs
> 0x8000000{5,6} so we need to check those before doing the detection.
>
> Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx>
> ---
> arch/x86/kernel/cpu/common.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index d239977f361f..ebab0e77e691 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -940,7 +940,8 @@ void __init identify_boot_cpu(void)
> #else
> vgetcpu_set_mode();
> #endif
> - if (boot_cpu_data.cpuid_level >= 2)
> + if (boot_cpu_data.cpuid_level >= 2 ||
> + boot_cpu_data.extended_cpuid_level >= 0x80000006)
> cpu_detect_tlb(&boot_cpu_data);
> }
>

This really belongs in cpu_detect_tlb() itself (or rather, in the
subfunctions called by it.) Can we just lose the general test here, please?

-hpa

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