From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756539AbYDJJsV (ORCPT ); Thu, 10 Apr 2008 05:48:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753314AbYDJJsM (ORCPT ); Thu, 10 Apr 2008 05:48:12 -0400 Received: from hellhawk.shadowen.org ([80.68.90.175]:4523 "EHLO hellhawk.shadowen.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752265AbYDJJsL (ORCPT ); Thu, 10 Apr 2008 05:48:11 -0400 Date: Thu, 10 Apr 2008 10:46:37 +0100 From: Andy Whitcroft To: Andi Kleen Cc: "H. Peter Anvin" , Steven Rostedt , LKML , Ingo Molnar , Peter Zijlstra , Linus Torvalds , akpm@osdl.org, Rusty Russell , Glauber de Oliveira Costa , Jan Beulich , Thomas Gleixner , pinskia@gcc.gnu.org Subject: Re: [PATCH] pop previous section in alternative.c Message-ID: <20080410094637.GW17915@shadowen.org> References: <47FD5D42.5000603@zytor.com> <87wsn6m6zt.fsf@basil.nowhere.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87wsn6m6zt.fsf@basil.nowhere.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 10, 2008 at 10:47:18AM +0200, Andi Kleen wrote: > "H. Peter Anvin" writes: > >>> > >> Oh, and this would not be complete without giving Andrew Pinski > >> complete > >> credit for telling me it wasn't a gcc bug but a bug in the toplevel asm > >> code in the kernel. ;-) > > We've actually had such bugs before, it isn't the first time. > > > > > In many ways it's kind of silly for this even to be in assembly, since > > all it is is a sequence of comma-separated byte values; I guess it was > > the easiest way to deal with it given the ".byte" prefix, but still... > > The nops are primarily used in inline assembler statements (in alternative) > and only once in this table. Not using this would have meant to write > them all twice which would have been nasty. There is also no sane > way to get standard arrays into inline assembler as instructions. > > BTW it looks like the problem was added with 121d7bf5a246d282ba91234d03a4edf9ccc9c940, > signed off by me, sorry for not catching it in review. > > Perhaps that is something that would make sense adding to checkpatch.pl? > Complain for .section in inline assembler without .previous or popsection > (cc Andy). I think such a check would make sense. Do you have an example of such a bad thing? My only concern is this sounds like a check which could potentially need to see more lines than are available in the patch context and so the test might be rather unreliable. -apw