From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754762AbZEZGLX (ORCPT ); Tue, 26 May 2009 02:11:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753361AbZEZGLP (ORCPT ); Tue, 26 May 2009 02:11:15 -0400 Received: from hera.kernel.org ([140.211.167.34]:34239 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753278AbZEZGLO (ORCPT ); Tue, 26 May 2009 02:11:14 -0400 Date: Tue, 26 May 2009 06:09:50 GMT From: tip-bot for Tejun Heo To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, JBeulich@novell.com, tj@kernel.org, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tj@kernel.org, JBeulich@novell.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <4A1B8150.40702@kernel.org> References: <4A1B8150.40702@kernel.org> Subject: [tip:x86/urgent] x86, relocs: ignore R_386_NONE in kernel relocation entries Message-ID: Git-Commit-ID: 46176b4f6bac19454b7b5c35f68594b85850a600 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Tue, 26 May 2009 06:09:51 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 46176b4f6bac19454b7b5c35f68594b85850a600 Gitweb: http://git.kernel.org/tip/46176b4f6bac19454b7b5c35f68594b85850a600 Author: Tejun Heo AuthorDate: Tue, 26 May 2009 14:42:40 +0900 Committer: H. Peter Anvin CommitDate: Mon, 25 May 2009 22:52:49 -0700 x86, relocs: ignore R_386_NONE in kernel relocation entries For relocatable 32bit kernels, boot/compressed/relocs.c processes relocation entries in the kernel image and appends it to the kernel image such that boot/compressed/head_32.S can relocate the kernel. The kernel image is one statically linked object and only uses two relocation types - R_386_PC32 and R_386_32, of the two only the latter needs massaging during kernel relocation and thus handled by relocs. R_386_PC32 is ignored and all other relocation types are considered error. When the target of a relocation resides in a discarded section, binutils doesn't throw away the relocation record but nullifies it by changing it to R_386_NONE, which unfortunately makes relocs fail. The problem was triggered by yet out-of-tree x86 stack unwind patches but given the binutils behavior, ignoring R_386_NONE is the right thing to do. The problem has been tracked down to binutils behavior by Jan Beulich. [ Impact: fix build with certain binutils by ignoring R_386_NONE ] Signed-off-by: Tejun Heo Cc: Jan Beulich Cc: Ingo Molnar LKML-Reference: <4A1B8150.40702@kernel.org> Signed-off-by: H. Peter Anvin --- arch/x86/boot/compressed/relocs.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c index 857e492..bbeb0c3 100644 --- a/arch/x86/boot/compressed/relocs.c +++ b/arch/x86/boot/compressed/relocs.c @@ -504,8 +504,11 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym)) if (sym->st_shndx == SHN_ABS) { continue; } - if (r_type == R_386_PC32) { - /* PC relative relocations don't need to be adjusted */ + if (r_type == R_386_NONE || r_type == R_386_PC32) { + /* + * NONE can be ignored and and PC relative + * relocations don't need to be adjusted. + */ } else if (r_type == R_386_32) { /* Visit relocations that need to be adjusted */