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From 9985cbbf4073ce9d0beec66bf702db9123758852 Mon Sep 17 00:00:00 2001
From: Peter Jones <>
Date: Wed, 29 May 2019 10:11:24 -0400
Subject: [PATCH 21/63] Fix up efi_guid_cmp()'s alignment problem a different

With the prior fix for efi_guid_cmp()'s alignment issue, abicheck shows:

1 function with some indirect sub-type change:

  [C]'function int efi_guid_cmp(void* const, void* const)' at <built-in>:34:1 has some indirect sub-type changes:
    parameter 1 of type 'void* const' changed:
      entity changed from 'void* const' to 'const efi_guid_t*'
      type size hasn't changed
    parameter 2 of type 'void* const' changed:
      entity changed from 'void* const' to 'const efi_guid_t*'
      type size hasn't changed

While this isn't a meaningful ABI difference in terms of linking, it is
definitely worse than having the type actually specified.

This patch changes the type back to the previous type, but also changes
the typedef to require a 1-byte alignment.  This will guarantee that all
new builds of efi_guid_cmp() and related code have code generated in a
way that's compatible with any alignment, thus alleviating the issue.

Signed-off-by: Peter Jones <>
 src/guid.c                  | 2 +-
 src/include/efivar/efivar.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/guid.c b/src/guid.c
index 3156b3b7c60..306c9ff8287 100644
--- a/src/guid.c
+++ b/src/guid.c
@@ -31,7 +31,7 @@
 extern const efi_guid_t efi_guid_zero;
-efi_guid_cmp(const void * const a, const void * const b)
+efi_guid_cmp(const efi_guid_t *a, const efi_guid_t *b)
 	return memcmp(a, b, sizeof (efi_guid_t));
diff --git a/src/include/efivar/efivar.h b/src/include/efivar/efivar.h
index ff95cb10791..11d9a9d7b78 100644
--- a/src/include/efivar/efivar.h
+++ b/src/include/efivar/efivar.h
@@ -37,7 +37,7 @@ typedef struct {
 	uint16_t	c;
 	uint16_t	d;
 	uint8_t		e[6];
-} efi_guid_t;
+} efi_guid_t __attribute__((__aligned__(1)));
 typedef struct {
 	uint8_t		addr[4];
@@ -128,7 +128,7 @@ extern int efi_symbol_to_guid(const char *symbol, efi_guid_t *guid)
 extern int efi_guid_is_zero(const efi_guid_t *guid);
 extern int efi_guid_is_empty(const efi_guid_t *guid);
-extern int efi_guid_cmp(const void * const a, const void * const b);
+extern int efi_guid_cmp(const efi_guid_t *a, const efi_guid_t *b);
 /* import / export functions */
 typedef struct efi_variable efi_variable_t;