From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:42087 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752407AbXFOL4m (ORCPT ); Fri, 15 Jun 2007 07:56:42 -0400 From: Andi Kleen Subject: Re: [PATCH] Introduce compat_u64 and compat_s64 types Date: Fri, 15 Jun 2007 13:55:57 +0200 References: <200706150159.l5F1xNgM000459@hera.kernel.org> <200706151128.39566.arnd@arndb.de> <200706151131.38429.arnd@arndb.de> In-Reply-To: <200706151131.38429.arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200706151355.57464.ak@suse.de> Sender: linux-arch-owner@vger.kernel.org To: Arnd Bergmann Cc: Benjamin Herrenschmidt , David Woodhouse , Linux Kernel Mailing List , Dave Airlie , linux-arch@vger.kernel.org, Andrew Morton List-ID: On Friday 15 June 2007 11:31:37 Arnd Bergmann wrote: > One common problem with 32 bit system call and ioctl emulation > is the different alignment rules between i386 and 64 bit machines. > A number of drivers work around this by marking the compat > structures as 'attribute((packed))', which is not the right > solution because it breaks all the non-x86 architectures that > want to use the same compat code. Why does it break them? It should just make them a little slower. The network code requires unaligned accesses to work anyways so if your architecture doesn't support them it is already remotely crashable. -Andi