Commit 79e03011 authored by Ian Campbell's avatar Ian Campbell Committed by Andi Kleen

[PATCH] i386: Allow i386 crash kernels to handle x86_64 dumps

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: default avatarIan Campbell <ian.campbell@xensource.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Acked-by: default avatarVivek Goyal <vgoyal@in.ibm.com>
Cc: Horms <horms@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent eab0c72a
......@@ -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 ||
......
......@@ -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
......
......@@ -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
#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 */
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