[PATCH v4 09/12] firmware: google: Pack structures for coreboot table entries

[Thomas Zimmermann <tzimmermann@suse.de>]

Pack the fields in the coreboot table entries. These entries are part of
the coreboot ABI, so they don't follow regular calling conventions. Fields
of type u64 are aligned to boundaries of 4 bytes instead of 8. [1]

So far this has not been a problem. In the future, padding bytes should
be added where explicit alignment is required.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://github.com/coreboot/coreboot/blob/main/payloads/libpayload/include/coreboot_tables.h#L96 # [1]
Suggested-by: Julius Werner <jwerner@chromium.org>
Acked-by: Julius Werner <jwerner@chromium.org>
Acked-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
v2:
- use aligned 64-bit type instead of __packed__ attribute (Julius)
---
 include/linux/coreboot.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/coreboot.h b/include/linux/coreboot.h
index 48705b439c6e..5746b99a070d 100644
--- a/include/linux/coreboot.h
+++ b/include/linux/coreboot.h
@@ -12,8 +12,11 @@
 #ifndef _LINUX_COREBOOT_H
 #define _LINUX_COREBOOT_H
 
+#include <linux/compiler_attributes.h>
 #include <linux/types.h>
 
+typedef __aligned(4) u64 cb_u64;
+
 /* List of coreboot entry structures that is used */
 
 #define CB_TAG_FRAMEBUFFER 0x12
@@ -30,7 +33,7 @@ struct lb_cbmem_ref {
 	u32 tag;
 	u32 size;
 
-	u64 cbmem_addr;
+	cb_u64 cbmem_addr;
 };
 
 /* Corresponds to LB_TAG_CBMEM_ENTRY */
@@ -38,7 +41,7 @@ struct lb_cbmem_entry {
 	u32 tag;
 	u32 size;
 
-	u64 address;
+	cb_u64 address;
 	u32 entry_size;
 	u32 id;
 };
@@ -48,7 +51,7 @@ struct lb_framebuffer {
 	u32 tag;
 	u32 size;
 
-	u64 physical_address;
+	cb_u64 physical_address;
 	u32 x_resolution;
 	u32 y_resolution;
 	u32 bytes_per_line;
-- 
2.52.0