Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933298AbZIDQzV (ORCPT ); Fri, 4 Sep 2009 12:55:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932751AbZIDQzU (ORCPT ); Fri, 4 Sep 2009 12:55:20 -0400 Received: from terminus.zytor.com ([198.137.202.10]:60407 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932706AbZIDQzT (ORCPT ); Fri, 4 Sep 2009 12:55:19 -0400 Message-ID: <4AA145E6.8000603@zytor.com> Date: Fri, 04 Sep 2009 09:52:54 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Tejun Heo , mingo@redhat.com, linux-kernel@vger.kernel.org, jeremy.fitzhardinge@citrix.com, stable@kernel.org, tglx@linutronix.de, mingo@elte.hu, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/asm] x86/i386: Make sure stack-protector segment base is cache aligned References: <4AA01893.6000507@goop.org> <4AA02687.9080406@zytor.com> <4AA02B02.7080101@goop.org> <4AA031DE.2070109@zytor.com> <4AA080A0.7010804@kernel.org> <4AA08283.5020306@kernel.org> <4AA08B09.50503@zytor.com> <4AA139DF.3050902@goop.org> In-Reply-To: <4AA139DF.3050902@goop.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 755 Lines: 23 On 09/04/2009 09:01 AM, Jeremy Fitzhardinge wrote: >>> >> It's correct that it doesn't make any difference for access, only for load. >> > > Well, to be completely precise, restore. When returning to usermode, > the "pop %seg" is slightly faster if you're restoring a null selector, > which is typically the case for %fs as 32-bit usermode doesn't use it. > That's a segment load... -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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/