Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966007AbWKIOCy (ORCPT ); Thu, 9 Nov 2006 09:02:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S966008AbWKIOCy (ORCPT ); Thu, 9 Nov 2006 09:02:54 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:10374 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S966007AbWKIOCx (ORCPT ); Thu, 9 Nov 2006 09:02:53 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Magnus Damm Cc: linux-kernel@vger.kernel.org, Vivek Goyal , Andi Kleen , magnus.damm@gmail.com, fastboot@lists.osdl.org, Horms , Dave Anderson Subject: Re: [PATCH 02/02] Elf: Align elf notes properly References: <20061102101942.452.73192.sendpatchset@localhost> <20061102101949.452.23441.sendpatchset@localhost> Date: Thu, 09 Nov 2006 07:00:22 -0700 In-Reply-To: <20061102101949.452.23441.sendpatchset@localhost> (Magnus Damm's message of "Thu, 02 Nov 2006 19:19:49 +0900") Message-ID: User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1726 Lines: 38 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. Eric - 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/