[PATCH v2 5/7] common: malloc: ensure alignment is always at least 8 byte

[Ahmad Fatoum]

We used to have following alignments:
		32-bit CPU	64-bit CPU
   dummy	8 bytes		 8 bytes
   dlmalloc	8 bytes		16 bytes
   tlsf		4 bytes		 8 bytes

With recent change to TLSF, we now always have at least 8 bytes as
alignment. To make this clearer, define a new CONFIG_MALLOC_ALIGNMENT
and either use it as the alignment (as done for dummy) or add static
asserts to ensure we have at least this alignment.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 common/Kconfig        | 5 +++++
 common/dlmalloc.c     | 3 +++
 common/dummy_malloc.c | 2 +-
 common/tlsf.c         | 2 ++
 4 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/common/Kconfig b/common/Kconfig
index afa591cb76ff..15c648de5d79 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -277,6 +277,11 @@ config MALLOC_SIZE
 	hex
 	default 0x400000
 	prompt "malloc area size"
+
+config MALLOC_ALIGNMENT
+	hex
+	default 8
+
 endmenu
 
 config BROKEN
diff --git a/common/dlmalloc.c b/common/dlmalloc.c
index ae10c9ae30dd..16ea3cafb624 100644
--- a/common/dlmalloc.c
+++ b/common/dlmalloc.c
@@ -3,6 +3,7 @@
 #include <malloc.h>
 #include <string.h>
 #include <memory.h>
+#include <linux/build_bug.h>
 
 #include <stdio.h>
 #include <module.h>
@@ -884,6 +885,8 @@ static mbinptr av_[NAV * 2 + 2] = {
 
 /*  Other static bookkeeping data */
 
+static_assert(MALLOC_ALIGNMENT >= CONFIG_MALLOC_ALIGNMENT);
+
 /* variables holding tunable values */
 #ifndef __BAREBOX__
 static unsigned long trim_threshold = DEFAULT_TRIM_THRESHOLD;
diff --git a/common/dummy_malloc.c b/common/dummy_malloc.c
index d99b5059cf91..7a96afec76e0 100644
--- a/common/dummy_malloc.c
+++ b/common/dummy_malloc.c
@@ -23,7 +23,7 @@ void *memalign(size_t alignment, size_t bytes)
 
 void *malloc(size_t size)
 {
-	return memalign(8, size);
+	return memalign(CONFIG_MALLOC_ALIGNMENT, size);
 }
 
 void free(void *ptr)
diff --git a/common/tlsf.c b/common/tlsf.c
index 692dabbdedd9..ba2ed367c0b9 100644
--- a/common/tlsf.c
+++ b/common/tlsf.c
@@ -96,6 +96,8 @@ tlsf_static_assert(sizeof(unsigned int) * CHAR_BIT >= SL_INDEX_COUNT);
 /* Ensure we've properly tuned our sizes. */
 tlsf_static_assert(ALIGN_SIZE == SMALL_BLOCK_SIZE / SL_INDEX_COUNT);
 
+tlsf_static_assert(ALIGN_SIZE >= CONFIG_MALLOC_ALIGNMENT);
+
 /*
 ** Data structures and associated constants.
 */
-- 
2.39.2