libpayload: Remove unused FLAG_USED from memory allocator
The FLAG_USED bit in the memory allocator's header type was never
read. This removes it to save one bit for the region size so we can
have heaps of up to 32MiB.
Change-Id: Ibd78e67d79e872d6df426516667c795fd52326d5
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/1942
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/payloads/libpayload/libc/malloc.c b/payloads/libpayload/libc/malloc.c
index 82bae3c..7756a3b 100644
--- a/payloads/libpayload/libc/malloc.c
+++ b/payloads/libpayload/libc/malloc.c
@@ -37,6 +37,9 @@
* We're also susceptible to the usual buffer overrun poisoning, though the
* risk is within acceptable ranges for this implementation (don't overrun
* your buffers, kids!).
+ *
+ * The header format (hdrtype_t) supports heaps of up to 32MiB (given that int
+ * is 32 bits long).
*/
#define IN_MALLOC_C
@@ -51,14 +54,15 @@
#define MAGIC (0x2a << 26)
#define FLAG_FREE (1 << 25)
-#define FLAG_USED (1 << 24)
+#define SIZE_BITS 25
+#define MAX_SIZE ((1 << SIZE_BITS) - 1)
-#define SIZE(_h) ((_h) & 0xFFFFFF)
+#define SIZE(_h) ((_h) & MAX_SIZE)
-#define _HEADER(_s, _f) ((hdrtype_t) (MAGIC | (_f) | ((_s) & 0xFFFFFF)))
+#define _HEADER(_s, _f) ((hdrtype_t) (MAGIC | (_f) | ((_s) & MAX_SIZE)))
#define FREE_BLOCK(_s) _HEADER(_s, FLAG_FREE)
-#define USED_BLOCK(_s) _HEADER(_s, FLAG_USED)
+#define USED_BLOCK(_s) _HEADER(_s, 0)
#define HDRSIZE (sizeof(hdrtype_t))
@@ -91,7 +95,7 @@
/* Align the size. */
len = (len + 3) & ~3;
- if (!len || len > 0xffffff)
+ if (!len || len > MAX_SIZE)
return (void *)NULL;
/* Make sure the region is setup correctly. */