Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762273AbYARS5I (ORCPT ); Fri, 18 Jan 2008 13:57:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763953AbYARS4s (ORCPT ); Fri, 18 Jan 2008 13:56:48 -0500 Received: from mx1.redhat.com ([66.187.233.31]:46119 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763635AbYARS4r (ORCPT ); Fri, 18 Jan 2008 13:56:47 -0500 Date: Fri, 18 Jan 2008 13:56:35 -0500 From: Dave Jones To: "Pallipadi, Venkatesh" Cc: Ingo Molnar , Yinghai Lu , LKML Subject: Re: [PATCH] X86: fix typo PAT to X86_PAT Message-ID: <20080118185635.GD10167@redhat.com> Mail-Followup-To: Dave Jones , "Pallipadi, Venkatesh" , Ingo Molnar , Yinghai Lu , LKML References: <20080118123140.GI11044@elte.hu> <20080118182437.GA10167@redhat.com> <924EFEDD5F540B4284297C4DC59F3DEE62B7BA@orsmsx423.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <924EFEDD5F540B4284297C4DC59F3DEE62B7BA@orsmsx423.amr.corp.intel.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1303 Lines: 29 On Fri, Jan 18, 2008 at 10:47:05AM -0800, Venki Pallipadi wrote: > >This exclusion is going to be a real pain in the ass for > >distro kernels. > >It's impossible for example to build a kernel that will now support > >the MTRR-alike registers on the AMD K6/early Cyrix etc and also > >support PAT. > > Actually, this exclusion will not work at all with the current code. > Infact it should be PAT selects MTRR, for the current code. As > pat_init() is called during mtrr init as the rules for how to change PAT > and how to change MTRR are same. Further, MTRR is always required on > SMP, as we read the MTRR setting from boot CPU and set it on Aps at boot > time. We should only remove the /proc/mtrr write permissions with > CONFIG_PAT. We need to deprecate it for a while before that... > Ingo, can you remove this PAT MTRR exclusion. The removal of write-permission also needs to be decided at runtime rather than compile time, or we screw over the "doesn't support PAT" CPUs in distro kernels. Dave -- http://www.codemonkey.org.uk -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/