efi/x86: Disallow efi=old_map in mixed mode

Before:

  1f299fad1e31: ("efi/x86: Limit EFI old memory map to SGI UV machines")

enabling the old EFI memory map on mixed mode systems
disabled EFI runtime services altogether.

Given that efi=old_map is a debug feature designed to work around
firmware problems related to EFI runtime services, and disabling
them can be achieved more straightforwardly using 'noefi' or
'efi=noruntime', it makes more sense to ignore efi=old_map on
mixed mode systems.

Currently, we do neither, and try to use the old memory map in
combination with mixed mode routines, which results in crashes,
so let's fix this by making efi=old_map functional on native
systems only.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/platform/uv/bios_uv.c b/arch/x86/platform/uv/bios_uv.c
index 7c2b8c5d0b496ccbe61a9b1150b778b5e03d61d8..607f58147311c7bb763fce47b12fece4c9167458 100644 (file)
--- a/arch/x86/platform/uv/bios_uv.c
+++ b/arch/x86/platform/uv/bios_uv.c
@@ -371,7 +371,7 @@ static int __init arch_parse_efi_cmdline(char *str)
                return -EINVAL;
        }
 
-       if (parse_option_str(str, "old_map"))
+       if (!efi_is_mixed() && parse_option_str(str, "old_map"))
                set_bit(EFI_UV1_MEMMAP, &efi.flags);
 
        return 0;