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authorSai Praneeth <sai.praneeth.prakhya@intel.com>2017-05-26 14:36:49 +0300
committerIngo Molnar <mingo@kernel.org>2017-05-28 12:06:16 +0300
commit4e52797d2efefac3271abdc54439a3435abd77b9 (patch)
tree41ca4de5ff8e1faff7dbb3b327ad30fb1f6657fa
parent684e3f965d0be8c26fedefe94f637374242aba08 (diff)
downloadlinux-4e52797d2efefac3271abdc54439a3435abd77b9.tar.xz
x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map
Booting kexec kernel with "efi=old_map" in kernel command line hits kernel panic as shown below. BUG: unable to handle kernel paging request at ffff88007fe78070 IP: virt_efi_set_variable.part.7+0x63/0x1b0 PGD 7ea28067 PUD 7ea2b067 PMD 7ea2d067 PTE 0 [...] Call Trace: virt_efi_set_variable() efi_delete_dummy_variable() efi_enter_virtual_mode() start_kernel() x86_64_start_reservations() x86_64_start_kernel() start_cpu() [ efi=old_map was never intended to work with kexec. The problem with using efi=old_map is that the virtual addresses are assigned from the memory region used by other kernel mappings; vmalloc() space. Potentially there could be collisions when booting kexec if something else is mapped at the virtual address we allocated for runtime service regions in the initial boot - Matt Fleming ] Since kexec was never intended to work with efi=old_map, disable runtime services in kexec if booted with efi=old_map, so that we don't panic. Tested-by: Lee Chun-Yi <jlee@suse.com> Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Acked-by: Dave Young <dyoung@redhat.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Shankar <ravi.v.shankar@intel.com> Cc: Ricardo Neri <ricardo.neri@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20170526113652.21339-4-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/platform/efi/efi.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 7e76a4d8304b..43b96f5f78ba 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -828,9 +828,11 @@ static void __init kexec_enter_virtual_mode(void)
/*
* We don't do virtual mode, since we don't do runtime services, on
- * non-native EFI
+ * non-native EFI. With efi=old_map, we don't do runtime services in
+ * kexec kernel because in the initial boot something else might
+ * have been mapped at these virtual addresses.
*/
- if (!efi_is_native()) {
+ if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
efi_memmap_unmap();
clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
return;