x86/efi: Allocate e820 buffer before calling efi_exit_boot_service

The following commit:

  d64934019f6c ("x86/efi: Use efi_exit_boot_services()")

introduced a regression on systems with large memory maps causing them
to hang on boot. The first "goto get_map" that was removed from
exit_boot() ensured there was enough room for the memory map when
efi_call_early(exit_boot_services) was called. This happens when
(nr_desc > ARRAY_SIZE(params->e820_table).

Chain of events:

  exit_boot()
    efi_exit_boot_services()
      efi_get_memory_map                  <- at this point the mm can't grow over 8 desc
      priv_func()
        exit_boot_func()
          allocate_e820ext()              <- new mm grows over 8 desc from e820 alloc
      efi_call_early(exit_boot_services)  <- mm key doesn't match so retry
      efi_call_early(get_memory_map)      <- not enough room for new mm
      system hangs

This patch allocates the e820 buffer before calling efi_exit_boot_services()
and fixes the regression.

 [ mingo: minor cleanliness edits. ]

Signed-off-by: Eric Snowberg <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>
Cc: <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Arend van Spriel <[email protected]>
Cc: Bhupesh Sharma <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Hans de Goede <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Jon Hunter <[email protected]>
Cc: Julien Thierry <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Matt Fleming <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sai Praneeth Prakhya <[email protected]>
Cc: Sedat Dilek <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: YiFei Zhu <[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