From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763036AbXGSUw4 (ORCPT ); Thu, 19 Jul 2007 16:52:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755808AbXGSUwu (ORCPT ); Thu, 19 Jul 2007 16:52:50 -0400 Received: from gw.goop.org ([64.81.55.164]:52818 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755147AbXGSUwt (ORCPT ); Thu, 19 Jul 2007 16:52:49 -0400 Message-ID: <469FCEE7.8060900@goop.org> Date: Thu, 19 Jul 2007 13:51:51 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.4 (X11/20070615) MIME-Version: 1.0 To: Andi Kleen CC: patches@x86-64.org, Zachary Amsden , Mathieu Desnoyers , Rusty Russell , linux-kernel@vger.kernel.org, "S. P. Prasanna" , Chris Wright Subject: Re: [patches] new text patching for review References: <200707191105.44056.ak@suse.de> <469FC9D4.5070604@goop.org> <200707192246.58047.ak@suse.de> In-Reply-To: <200707192246.58047.ak@suse.de> X-Enigmail-Version: 0.95.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: > Normally there are not that many NMIs or MCEs at boot, but it would > be still good to avoid the very rare crash by auditing the code first > [better than try to debug it on some production system later] > Auditing it for what? If we want to make patching safe against NMI/MCE, I guess we need to make sure those handlers don't use any pvops, but that seems unreasonable if they want to poke at MSRs and so on. > In theory yes, in practice there can be errata of course. There tend > to be a couple with self modifying code, especially cross modifying > (from another CPU) -- but you don't do that. > No, but the pv-ops patching code should have no requirement for atomicity at all; we shouldn't be trying to patch a live instruction stream. J