[tip:efi/urgent] efi: Align 'efi_guid_t' to 64 bits

[tip-bot for Heinrich Schuchardt]

Commit-ID:  793423cf07e51e3185b8680167115813589c057d
Gitweb:     https://git.kernel.org/tip/793423cf07e51e3185b8680167115813589c057d
Author:     Heinrich Schuchardt <xypron.glpk@xxxxxx>
AuthorDate: Mon, 17 Dec 2018 19:02:14 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 17 Dec 2018 19:12:48 +0100

efi: Align 'efi_guid_t' to 64 bits

The UEFI Specification Version 2.7 Errata A defines:

  "EFI_GUID
  128-bit buffer containing a unique identifier value.
  Unless otherwise specified, aligned on a 64-bit boundary."

Before this patch efi_guid_t was only 8-bit aligned.

Note that this could potentially trigger alignment faults during
EFI runtime services calls on 32-bit ARM, given that it does not
permit load/store double or load/store multiple instructions to
operate on memory addresses that are not 32-bit aligned.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.9+, or earlier if possible
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-efi@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20181217180214.9436-3-ard.biesheuvel@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 include/linux/efi.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/efi.h b/include/linux/efi.h
index 100ce4a4aff6..e6480c805932 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -48,7 +48,7 @@ typedef u16 efi_char16_t;		/* UNICODE character */
 typedef u64 efi_physical_addr_t;
 typedef void *efi_handle_t;
 
-typedef guid_t efi_guid_t;
+typedef guid_t efi_guid_t __aligned(8);
 
 #define EFI_GUID(a,b,c,d0,d1,d2,d3,d4,d5,d6,d7) \
 	GUID_INIT(a, b, c, d0, d1, d2, d3, d4, d5, d6, d7)