From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937438AbXGTWfQ (ORCPT ); Fri, 20 Jul 2007 18:35:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755583AbXGTWfE (ORCPT ); Fri, 20 Jul 2007 18:35:04 -0400 Received: from terminus.zytor.com ([198.137.202.10]:35447 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754885AbXGTWfC (ORCPT ); Fri, 20 Jul 2007 18:35:02 -0400 Message-ID: <46A13859.7020608@zytor.com> Date: Fri, 20 Jul 2007 15:34:01 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.0 (X11/20070419) MIME-Version: 1.0 To: "Luck, Tony" CC: Andi Kleen , Andreas Schwab , Randy Dunlap , Arthur Jones , Vasily Tarasov , linux-kernel@vger.kernel.org, Jan Kara , linux-arch@vger.kernel.org Subject: Re: build fix for x86_64... References: <617E1C2C70743745A92448908E030B2A01FA4C43@scsmsx411.amr.corp.intel.com> In-Reply-To: <617E1C2C70743745A92448908E030B2A01FA4C43@scsmsx411.amr.corp.intel.com> X-Enigmail-Version: 0.95.0 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 Luck, Tony wrote: > At the moment our problem is that there is some code that has > been added to handle the compatability problem caused by u64 > objects having different alignment when running on 32-bit and > 64-bit systems. This only affects ia64 and x86-64 because all > the other 32/64 bit capable systems wisely avoided this issue > by making 64-bit objects *always* 8-byte aligned. > It is possible that in the future more such issues will arise > (either because we find some more existing interfaces that > have this problem, or because new interfaces are introduced > that also have this problem). Such new code will also require > some compatability functions. These functions will also only > be needed on ia64 and x86-64, and even on these systems the > code will only be needed if CONFIG_COMPAT=y The issue here is I was looking at it from a new interfaces perspective, and not from a legacy interfaces perspective. However, for new interfaces we want the opposite -- properly aligned elements -- so please disregard previous objection. However, I'm still thinking it might be worthwhile to consider the __i[us]64 typedefs previously discussed as a way to avoid alignment bloopers in new interfaces. -hpa