From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755414AbYCYBbB (ORCPT ); Mon, 24 Mar 2008 21:31:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752135AbYCYBay (ORCPT ); Mon, 24 Mar 2008 21:30:54 -0400 Received: from terminus.zytor.com ([198.137.202.10]:48911 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751952AbYCYBax (ORCPT ); Mon, 24 Mar 2008 21:30:53 -0400 Message-ID: <47E85593.4030104@zytor.com> Date: Mon, 24 Mar 2008 18:29:55 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: yhlu.kernel@gmail.com CC: Ingo Molnar , Thomas Gleixner , Andrew Morton , kernel list Subject: Re: [PATCH] x86: enable PAT for amd k8 and fam10h References: <200803241602.01957.yhlu.kernel@gmail.com> In-Reply-To: <200803241602.01957.yhlu.kernel@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yinghai Lu wrote: > [PATCH] x86: enable PAT for amd k8 and fam10h > > make known_pat_cpu to think amd k8 and fam10h is ok too. > > also make tom2 below to be WRBACK > > diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c > index f74505f..a9e1a27 100644 > --- a/arch/x86/mm/pat.c > +++ b/arch/x86/mm/pat.c > @@ -49,6 +49,12 @@ static int pat_known_cpu(void) > return 1; > } > } > + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD && > + boot_cpu_data.x86 >= 0xf && boot_cpu_data.x86 <= 0x11) { > + if (cpu_has_pat) { > + return 1; > + } > + } > > pat_wc_enabled = 0; > printk(KERN_INFO "CPU and/or kernel does not support PAT.\n"); This really should be handled through a CPU flag. Specifically, it should be handled by disabling the PAT flag if PAT is unusable or suspect of being unusable; it should *NOT* be stashed away in a completely separate piece of code. -hpa