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 <[email protected]>
Signed-off-by: Sai Praneeth Prakhya <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Acked-by: Dave Young <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Shankar <[email protected]>
Cc: Ricardo Neri <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions