linux-kernel - RE: [PATCH 2/3] x86, intel: Use cpu

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Date:	Mon, 29 Aug 2011 18:08:46 -0700
From:	"Yu, Fenghua" <fenghua.yu@...el.com>
To:	Andi Kleen <andi@...stfloor.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:	"x86@...nel.org" <x86@...nel.org>, Andi Kleen <ak@...ux.intel.com>,
	"jbeulich@...ell.com" <jbeulich@...ell.com>,
	"khali@...ux-fr.org" <khali@...ux-fr.org>,
	"Yu, Fenghua" <fenghua.yu@...el.com>
Subject: RE: [PATCH 2/3] x86, intel: Use cpu_update for Atom errata check

>--- a/arch/x86/kernel/cpu/intel.c
>+++ b/arch/x86/kernel/cpu/intel.c
>@@ -55,17 +55,10 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
>        * need the microcode to have already been loaded... so if it is
>        * not, recommend a BIOS update and disable large pages.
 >      */
>-       if (c->x86 == 6 && c->x86_model == 0x1c && c->x86_mask <= 2) {
>-               u32 ucode, junk;
>-
>-               wrmsr(MSR_IA32_UCODE_REV, 0, 0);
>-               sync_core();
>-               rdmsr(MSR_IA32_UCODE_REV, junk, ucode);
>-
>-               if (ucode < 0x20e) {
>-                       printk(KERN_WARNING "Atom PSE erratum detected, BIOS microcode update recommended\n");
>-                       clear_cpu_cap(c, X86_FEATURE_PSE);
>-               }
>+       if (c->x86 == 6 && c->x86_model == 0x1c && c->x86_mask <= 2 &&
>+           c->microcode < 0x20e) {
>+               printk(KERN_WARNING "Atom PSE erratum detected, BIOS microcode update recommended\n");
>+               clear_cpu_cap(c, X86_FEATURE_PSE); 
>       }

c->microcode is used here BEFORE it's initialized in init_intel() in your patch set [1/3].

Thanks.

-Fenghua
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