From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752973AbXCPHRt (ORCPT ); Fri, 16 Mar 2007 03:17:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752988AbXCPHRt (ORCPT ); Fri, 16 Mar 2007 03:17:49 -0400 Received: from 207.47.60.147.static.nextweb.net ([207.47.60.147]:31383 "EHLO rpc.xensource.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752973AbXCPHRr (ORCPT ); Fri, 16 Mar 2007 03:17:47 -0400 Subject: Re: [PATCH 1/1] Allow i386 crash kernels to handle x86_64 dumps From: Ian Campbell To: Horms Cc: Vivek Goyal , hbabu@us.ibm.com, fastboot@lists.osdl.org, linux-kernel@vger.kernel.org, Magnus Damm In-Reply-To: <20070315234807.GB10861@verge.net.au> References: <1173891609.8591.41.camel@localhost.localdomain> <20070315014635.GC28396@verge.net.au> <20070315045536.GA6766@in.ibm.com> <20070315050754.GB22329@verge.net.au> <20070315054726.GC6766@in.ibm.com> <1173961378.8591.63.camel@localhost.localdomain> <20070315132616.GH6766@in.ibm.com> <20070315234807.GB10861@verge.net.au> Content-Type: text/plain Date: Fri, 16 Mar 2007 07:17:43 +0000 Message-Id: <1174029463.28658.25.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 16 Mar 2007 07:17:46.0534 (UTC) FILETIME=[32548460:01C7679B] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2007-03-16 at 08:48 +0900, Horms wrote: > > > > > > Signed-off-by: Ian Campbell > > > > > > diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c > > > index d960507..523e109 100644 > > > --- a/fs/proc/vmcore.c > > > +++ b/fs/proc/vmcore.c > > > @@ -514,7 +514,7 @@ static int __init parse_crash_elf64_headers(void) > > > /* Do some basic Verification. */ > > > if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 || > > > (ehdr.e_type != ET_CORE) || > > > - !elf_check_arch(&ehdr) || > > > + !vmcore_elf_check_arch(&ehdr) || > > > ehdr.e_ident[EI_CLASS] != ELFCLASS64 || > > > ehdr.e_ident[EI_VERSION] != EV_CURRENT || > > > ehdr.e_version != EV_CURRENT || > > > diff --git a/include/asm-i386/kexec.h b/include/asm-i386/kexec.h > > > index 4dfc9f5..c76737e 100644 > > > --- a/include/asm-i386/kexec.h > > > +++ b/include/asm-i386/kexec.h > > > @@ -47,6 +47,9 @@ > > > /* The native architecture */ > > > #define KEXEC_ARCH KEXEC_ARCH_386 > > > > > > +/* We can also handle crash dumps from 64 bit kernel. */ > > > +#define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64) > > > + > > > > Ideal place for this probably should have been arch dependent crash_dump.h > > file. But we don't have one and no point introducing one just for this > > macro. > > > > This change looks good to me. > > Won't the above change break non i386 archtectures as > vmcore_elf_check_arch_cross isn't defined for them? No, because of this hunk: diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h index 3250365..db60dac 100644 --- a/include/linux/crash_dump.h +++ b/include/linux/crash_dump.h @@ -14,5 +14,13 @@ extern ssize_t copy_oldmem_page(unsigned long, char *, size_t, extern const struct file_operations proc_vmcore_operations; extern struct proc_dir_entry *proc_vmcore; +/* Architecture code defines this if there are other possible ELF + * machine types, e.g. on bi-arch capable hardware. */ +#ifndef vmcore_elf_check_arch_cross(x) +#define vmcore_elf_check_arch_cross(x) 0 +#endif [snip]