Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424332AbWKJBHz (ORCPT ); Thu, 9 Nov 2006 20:07:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1424324AbWKJBHz (ORCPT ); Thu, 9 Nov 2006 20:07:55 -0500 Received: from koto.vergenet.net ([210.128.90.7]:47777 "EHLO koto.vergenet.net") by vger.kernel.org with ESMTP id S1424332AbWKJBHx (ORCPT ); Thu, 9 Nov 2006 20:07:53 -0500 Date: Fri, 10 Nov 2006 09:50:52 +0900 From: Horms To: "Eric W. Biederman" Cc: Magnus Damm , linux-kernel@vger.kernel.org, Vivek Goyal , Andi Kleen , magnus.damm@gmail.com, fastboot@lists.osdl.org, Dave Anderson Subject: Re: [PATCH 02/02] Elf: Align elf notes properly Message-ID: <20061110005051.GB4107@verge.net.au> References: <20061102101942.452.73192.sendpatchset@localhost> <20061102101949.452.23441.sendpatchset@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: mutt-ng/devel-r804 (Debian) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2051 Lines: 46 On Thu, Nov 09, 2006 at 07:00:22AM -0700, Eric W. Biederman wrote: > Magnus Damm writes: > > > elf: Align elf notes properly > > > > The kernel currently contains several elf note aligment implementations. Most > > implementations follow the spec on 32-bit platforms, but none current aligns > > the notes correctly on 64-bit platforms. This patch tries to fix this by > > interpreting the 64-bit and 32-bit elf specs as the following: > > > > offset bytes name > > 0 4 n_namesz -+ -+ > > 4 4 n_descsz | elf note header | > > 8 4 n_type -+ | elf note entry size - N4 > > 12 N1 name | > > N2 N3 desc -+ > > > > WS = word size in bytes (4 for 32 bit, 8 for 64 bit) > > N1 = roundup(n_namesz + sizeof(elf note header), WS) - sizeof(elf note header) > > N2 = sizeof(elf note header) + N1 > > N3 = roundup(n_descsz, WS) > > N4 = sizeof(elf note header) + N1 + N2 > > > > The elf note header contains three 32-bit values on 32-bit and 64-bit systems. > > The header is followed by name and desc data together with padding. The > > alignment and padding varies depending on the word size. > > I see your point and I disagree. The notes in a kernel generated > core dump do not vary in size. Find me some implementation evidence that > anyone ever added the extra 4 bytes of alignment to the description and the > padding fields and I will be ready to consider this. Currently this > just appears to be reading a draft spec that doesn't match reality. Or perhaps a spec that hasn't been implemented correctly. I guess that the real question is, what padding is correct? -- Horms H: http://www.vergenet.net/~horms/ W: http://www.valinux.co.jp/en/ - 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/