The patch titled
Allow i386 crash kernels to handle x86_64 dumps
has been removed from the -mm tree. Its filename was
allow-i386-crash-kernels-to-handle-x86_64-dumps.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: Allow i386 crash kernels to handle x86_64 dumps
From: Ian Campbell <ian.campbell@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxx: build fix]
Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxxxxx>
Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Horms <horms@xxxxxxxxxxxx>
Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/vmcore.c | 2 +-
include/asm-i386/kexec.h | 3 +++
include/linux/crash_dump.h | 8 ++++++++
3 files changed, 12 insertions(+), 1 deletion(-)
diff -puN fs/proc/vmcore.c~allow-i386-crash-kernels-to-handle-x86_64-dumps fs/proc/vmcore.c
--- a/fs/proc/vmcore.c~allow-i386-crash-kernels-to-handle-x86_64-dumps
+++ a/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 ||
diff -puN include/asm-i386/kexec.h~allow-i386-crash-kernels-to-handle-x86_64-dumps include/asm-i386/kexec.h
--- a/include/asm-i386/kexec.h~allow-i386-crash-kernels-to-handle-x86_64-dumps
+++ a/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
diff -puN include/linux/crash_dump.h~allow-i386-crash-kernels-to-handle-x86_64-dumps include/linux/crash_dump.h
--- a/include/linux/crash_dump.h~allow-i386-crash-kernels-to-handle-x86_64-dumps
+++ a/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 */
_
Patches currently in -mm which might be from ian.campbell@xxxxxxxxxxxxx are
-
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