commit b327a1e706f4fbb113ed7f17edcdc23bfa8c5828
author Dave Rodgman <dave.rodgman@arm.com> Tue Feb 06 11:21:26 2024 +0000
committer Dave Rodgman <dave.rodgman@arm.com> Tue Feb 06 11:32:01 2024 +0000
tree e003715b88c2dba5c3394a4d13b8d73c8029e438
parent 32c28cebb41a25bb4e18d3a530b59c0e5929a324

Change unaligned access method for old gcc

gcc bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94662 shows
that __attribute__ aligned may be ignored.

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>

library/alignment.h

diff --git a/library/alignment.h b/library/alignment.h
index 248f29b..8db550f 100644
--- a/library/alignment.h
+++ b/library/alignment.h
@@ -71,10 +71,10 @@
  * Tested with several versions of GCC from 4.5.0 up to 9.3.0
  * We don't enable for older than 4.5.0 as this has not been tested.
  */
- #define UINT_UNALIGNED
-typedef uint16_t __attribute__((__aligned__(1))) mbedtls_uint16_unaligned_t;
-typedef uint32_t __attribute__((__aligned__(1))) mbedtls_uint32_unaligned_t;
-typedef uint64_t __attribute__((__aligned__(1))) mbedtls_uint64_unaligned_t;
+ #define UINT_UNALIGNED_UNION
+typedef union { uint16_t x; } __attribute__((packed)) mbedtls_uint16_unaligned_t;
+typedef union { uint32_t x; } __attribute__((packed)) mbedtls_uint32_unaligned_t;
+typedef union { uint64_t x; } __attribute__((packed)) mbedtls_uint64_unaligned_t;
  #endif
 
 /*
@@ -101,6 +101,9 @@
 #if defined(UINT_UNALIGNED)
     mbedtls_uint16_unaligned_t *p16 = (mbedtls_uint16_unaligned_t *) p;
     r = *p16;
+#elif defined(UINT_UNALIGNED_UNION)
+    mbedtls_uint16_unaligned_t *p16 = (mbedtls_uint16_unaligned_t *) p;
+    r = p16->x;
 #else
     memcpy(&r, p, sizeof(r));
 #endif
@@ -124,6 +127,9 @@
 #if defined(UINT_UNALIGNED)
     mbedtls_uint16_unaligned_t *p16 = (mbedtls_uint16_unaligned_t *) p;
     *p16 = x;
+#elif defined(UINT_UNALIGNED_UNION)
+    mbedtls_uint16_unaligned_t *p16 = (mbedtls_uint16_unaligned_t *) p;
+    p16->x = x;
 #else
     memcpy(p, &x, sizeof(x));
 #endif
@@ -147,6 +153,9 @@
 #if defined(UINT_UNALIGNED)
     mbedtls_uint32_unaligned_t *p32 = (mbedtls_uint32_unaligned_t *) p;
     r = *p32;
+#elif defined(UINT_UNALIGNED_UNION)
+    mbedtls_uint32_unaligned_t *p32 = (mbedtls_uint32_unaligned_t *) p;
+    r = p32->x;
 #else
     memcpy(&r, p, sizeof(r));
 #endif
@@ -170,6 +179,9 @@
 #if defined(UINT_UNALIGNED)
     mbedtls_uint32_unaligned_t *p32 = (mbedtls_uint32_unaligned_t *) p;
     *p32 = x;
+#elif defined(UINT_UNALIGNED_UNION)
+    mbedtls_uint32_unaligned_t *p32 = (mbedtls_uint32_unaligned_t *) p;
+    p32->x = x;
 #else
     memcpy(p, &x, sizeof(x));
 #endif
@@ -193,6 +205,9 @@
 #if defined(UINT_UNALIGNED)
     mbedtls_uint64_unaligned_t *p64 = (mbedtls_uint64_unaligned_t *) p;
     r = *p64;
+#elif defined(UINT_UNALIGNED_UNION)
+    mbedtls_uint64_unaligned_t *p64 = (mbedtls_uint64_unaligned_t *) p;
+    r = p64->x;
 #else
     memcpy(&r, p, sizeof(r));
 #endif
@@ -216,6 +231,9 @@
 #if defined(UINT_UNALIGNED)
     mbedtls_uint64_unaligned_t *p64 = (mbedtls_uint64_unaligned_t *) p;
     *p64 = x;
+#elif defined(UINT_UNALIGNED_UNION)
+    mbedtls_uint64_unaligned_t *p64 = (mbedtls_uint64_unaligned_t *) p;
+    p64->x = x;
 #else
     memcpy(p, &x, sizeof(x));
 #endif