diff --git a/common/common_defs.h b/common/common_defs.h
index 41e9feb..d4c2604 100644
--- a/common/common_defs.h
+++ b/common/common_defs.h
@@ -140,6 +140,7 @@ typedef size_t machine_word_t;
 #define MAX(a, b)		((a) >= (b) ? (a) : (b))
 #define DIV_ROUND_UP(n, d)	(((n) + (d) - 1) / (d))
 #define STATIC_ASSERT(expr)	((void)sizeof(char[1 - 2 * !(expr)]))
+#define ALIGN(n, a)		(((n) + (a) - 1) & ~((a) - 1))
 
 /* ========================================================================== */
 /*                           Endianness handling                              */
diff --git a/lib/aligned_malloc.c b/lib/aligned_malloc.c
index a852fdc..d00af19 100644
--- a/lib/aligned_malloc.c
+++ b/lib/aligned_malloc.c
@@ -25,15 +25,11 @@
 void *
 aligned_malloc(size_t alignment, size_t size)
 {
-	const uintptr_t mask = alignment - 1;
-	char *ptr = NULL;
-	char *raw_ptr;
-
-	raw_ptr = malloc(mask + sizeof(size_t) + size);
-	if (raw_ptr) {
-		ptr = (char *)raw_ptr + sizeof(size_t);
-		ptr = (void *)(((uintptr_t)ptr + mask) & ~mask);
-		*((size_t *)ptr - 1) = ptr - raw_ptr;
+	void *ptr = malloc(sizeof(void *) + alignment - 1 + size);
+	if (ptr) {
+		void *orig_ptr = ptr;
+		ptr = (void *)ALIGN((uintptr_t)ptr + sizeof(void *), alignment);
+		((void **)ptr)[-1] = orig_ptr;
 	}
 	return ptr;
 }
@@ -42,5 +38,5 @@ void
 aligned_free(void *ptr)
 {
 	if (ptr)
-		free((char *)ptr - *((size_t *)ptr - 1));
+		free(((void **)ptr)[-1]);
 }