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Message-ID: <86802c440805192249y77e78918u8392f5a43331365@mail.gmail.com>
Date: Mon, 19 May 2008 22:49:28 -0700
From: "Yinghai Lu" <yhlu.kernel@gmail.com>
To: "Dave Jones" <davej@redhat.com>
Subject: Re: [X86] Add recent Centaur CPUs to PAT whitelist
Cc: "Linux Kernel" <linux-kernel@vger.kernel.org>,
       "Ingo Molnar" <mingo@elte.hu>, "Thomas Gleixner" <tglx@linutronix.de>,
       hpa@zytor.com
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On Mon, May 19, 2008 at 9:09 PM, Dave Jones <davej@redhat.com> wrote:
> From conversation with Centaur engineers, both the newer generations
> of the VIA C7, and their future CPUs support PAT, with no known errata.
>
> Signed-off-by: Dave Jones <davej@redhat.com>
>
> diff --git a/arch/x86/kernel/cpu/addon_cpuid_features.c b/arch/x86/kernel/cpu/addon_cpuid_features.c
> index c2e1ce3..638a3a6 100644
> --- a/arch/x86/kernel/cpu/addon_cpuid_features.c
> +++ b/arch/x86/kernel/cpu/addon_cpuid_features.c
> @@ -62,6 +81,10 @@ void __cpuinit validate_pat_support(struct cpuinfo_x86 *c)
>                if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15))
>                        return;
>                break;
> +       case X86_VENDOR_CENTAUR:
> +               if ((c->x86 > 6) || (c->x86 == 6 && c->x86_model >= 10))
> +                       set_cpu_cap(c, X86_FEATURE_PAT);
> +               break;
>        }
>
>        pat_disable(cpu_has_pat ?

you may need to return early...

> +       case X86_VENDOR_CENTAUR:
> +               if ((c->x86 > 6) || (c->x86 == 6 && c->x86_model >= 10)) {
> +                       set_cpu_cap(c, X86_FEATURE_PAT); /* may not need, if cpuid already has that set */
> +                       return;
> +               }
> +               break;

YH