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>
1 file changed