Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753880AbYHNVrT (ORCPT ); Thu, 14 Aug 2008 17:47:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751332AbYHNVrI (ORCPT ); Thu, 14 Aug 2008 17:47:08 -0400 Received: from gw.goop.org ([64.81.55.164]:39971 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751324AbYHNVrH (ORCPT ); Thu, 14 Aug 2008 17:47:07 -0400 Message-ID: <48A4A7B4.3060008@goop.org> Date: Thu, 14 Aug 2008 14:46:28 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: Mathieu Desnoyers CC: Harvey Harrison , "H. Peter Anvin" , Andi Kleen , Linus Torvalds , Ingo Molnar , Steven Rostedt , Steven Rostedt , LKML , Thomas Gleixner , Peter Zijlstra , Andrew Morton , David Miller , Roland McGrath , Ulrich Drepper , Rusty Russell , Gregory Haskins , Arnaldo Carvalho de Melo , "Luis Claudio R. Goncalves" , Clark Williams , Christoph Lameter Subject: Re: [RFC PATCH] x86 alternatives : fix LOCK_PREFIX race with preemptible kernel and CPU hotplug References: <48A3A806.8060509@goop.org> <20080814151805.GA29507@Krystal> <48A459B1.2070601@zytor.com> <20080814165802.GC517@Krystal> <48A465F2.8000701@goop.org> <20080814173021.GA4697@Krystal> <48A46EC2.1010301@goop.org> <48A47B83.3090408@zytor.com> <20080814185338.GB7896@Krystal> <48A487A6.9060501@goop.org> <20080814203122.GC7896@Krystal> In-Reply-To: <20080814203122.GC7896@Krystal> X-Enigmail-Version: 0.95.6 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 Content-Length: 811 Lines: 20 Mathieu Desnoyers wrote: > I'm just worried about this comment from Harvey Harrison : > > arch/x86/mm/fault.c : is_prefetch() > > * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes. > * In X86_64 long mode, the CPU will signal invalid > * opcode if some of these prefixes are present so > * X86_64 will never get here anyway > I would say that comment is wrong. But we'd never put a lock prefix on a prefetch, so you won't be added a ds prefix either. J -- 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/