From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755959AbXD2LA3 (ORCPT ); Sun, 29 Apr 2007 07:00:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755191AbXD2Kxd (ORCPT ); Sun, 29 Apr 2007 06:53:33 -0400 Received: from ns.suse.de ([195.135.220.2]:52143 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755175AbXD2KxR (ORCPT ); Sun, 29 Apr 2007 06:53:17 -0400 From: Andi Kleen References: <200704291252.514680000@suse.de> In-Reply-To: <200704291252.514680000@suse.de> To: Ian Campbell , Horms , Magnus Damm , "Eric W. Biederman" , Andi Kleen , patches@x86-64.org, linux-kernel@vger.kernel.org Subject: [PATCH] [27/48] i386: Allow i386 crash kernels to handle x86_64 dumps Message-Id: <20070429105316.78A7D15108@wotan.suse.de> Date: Sun, 29 Apr 2007 12:53:16 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Ian Campbell The specific case I am encountering is kdump under Xen with a 64 bit hypervisor and 32 bit kernel/userspace. The dump created is 64 bit due to the hypervisor but the dump kernel is 32 bit for maximum compatibility. It's possibly less likely to be useful in a purely native scenario but I see no reason to disallow it. [akpm@linux-foundation.org: build fix] Signed-off-by: Ian Campbell Signed-off-by: Andi Kleen Acked-by: Vivek Goyal Cc: Horms Cc: Magnus Damm Cc: "Eric W. Biederman" Cc: Andi Kleen Signed-off-by: Andrew Morton --- fs/proc/vmcore.c | 2 +- include/asm-i386/kexec.h | 3 +++ include/linux/crash_dump.h | 8 ++++++++ 3 files changed, 12 insertions(+), 1 deletion(-) Index: linux/fs/proc/vmcore.c =================================================================== --- linux.orig/fs/proc/vmcore.c +++ linux/fs/proc/vmcore.c @@ -514,7 +514,7 @@ static int __init parse_crash_elf64_head /* 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 || Index: linux/include/asm-i386/kexec.h =================================================================== --- linux.orig/include/asm-i386/kexec.h +++ linux/include/asm-i386/kexec.h @@ -42,6 +42,9 @@ /* 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) + #define MAX_NOTE_BYTES 1024 /* CPU does not save ss and esp on stack if execution is already Index: linux/include/linux/crash_dump.h =================================================================== --- linux.orig/include/linux/crash_dump.h +++ linux/include/linux/crash_dump.h @@ -14,5 +14,13 @@ extern ssize_t copy_oldmem_page(unsigned 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 +#define vmcore_elf_check_arch_cross(x) 0 +#endif + +#define vmcore_elf_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x)) + #endif /* CONFIG_CRASH_DUMP */ #endif /* LINUX_CRASHDUMP_H */