Re: [PATCH v1 2/4] x86, CPU: Push TLB detection CPUID check down

From: Alex Shi
Date: Mon Aug 06 2012 - 20:35:58 EST


On 08/07/2012 01:00 AM, Borislav Petkov wrote:

> From: Borislav Petkov <borislav.petkov@xxxxxxx>
>
> Push the max CPUID leaf check into the ->detect_tlb function and remove
> general test case from the generic path.
>
> Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx>


Acked-by: Alex Shi <alex.shi@xxxxxxxxx>

> ---
> arch/x86/kernel/cpu/common.c | 3 +--
> arch/x86/kernel/cpu/intel.c | 4 ++++
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index d239977f361f..080f4a737e3e 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -940,8 +940,7 @@ void __init identify_boot_cpu(void)
> #else
> vgetcpu_set_mode();
> #endif
> - if (boot_cpu_data.cpuid_level >= 2)
> - cpu_detect_tlb(&boot_cpu_data);
> + cpu_detect_tlb(&boot_cpu_data);
> }
>
> void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index 0a4ce2980a5a..198e019a531a 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -648,6 +648,10 @@ static void __cpuinit intel_detect_tlb(struct cpuinfo_x86 *c)
> int i, j, n;
> unsigned int regs[4];
> unsigned char *desc = (unsigned char *)regs;
> +
> + if (c->cpuid_level < 2)
> + return;
> +
> /* Number of times to iterate */
> n = cpuid_eax(2) & 0xFF;
>


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