Let's sync definition with Linux, so we are able to pass efi_guid_t
types to function accepting guid_t. This has the added benefit of us
starting to observe alignment, which may become relevant with barebox
EFI on non-x86.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
include/efi.h | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/include/efi.h b/include/efi.h
index 3595cf05ccb7..1904caf3a4b6 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -14,6 +14,7 @@
*/
#include <linux/string.h>
#include <linux/types.h>
+#include <linux/uuid.h>
#ifdef CONFIG_EFI_BOOTUP
#define EFIAPI __attribute__((ms_abi))
@@ -66,10 +67,20 @@ typedef u16 efi_char16_t; /* UNICODE character */
typedef u64 efi_physical_addr_t;
typedef void *efi_handle_t;
-
-typedef struct {
- u8 b[16];
-} efi_guid_t;
+/*
+ * The UEFI spec and EDK2 reference implementation both define EFI_GUID as
+ * struct { u32 a; u16; b; u16 c; u8 d[8]; }; and so the implied alignment
+ * is 32 bits not 8 bits like our guid_t. In some cases (i.e., on 32-bit ARM),
+ * this means that firmware services invoked by the kernel may assume that
+ * efi_guid_t* arguments are 32-bit aligned, and use memory accessors that
+ * do not tolerate misalignment. So let's set the minimum alignment to 32 bits.
+ *
+ * Note that the UEFI spec as well as some comments in the EDK2 code base
+ * suggest that EFI_GUID should be 64-bit aligned, but this appears to be
+ * a mistake, given that no code seems to exist that actually enforces that
+ * or relies on it.
+ */
+typedef guid_t efi_guid_t __aligned(__alignof__(u32));
#define EFI_GUID(a, b, c, d0, d1, d2, d3, d4, d5, d6, d7) \
((efi_guid_t) \
--
2.39.2
