New patch to review for coreboot: 37a6cac Make libpaylod alloc() memory pointers volatile

[Marc Jones]

Marc Jones ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/705

-gerrit

commit 37a6cacf4e04d0ee9e75f1b1c7ea307d750623c6
Author: Marc Jones 
Date:   Thu Mar 1 16:12:11 2012 -0700

Make libpaylod alloc() memory pointers volatile

gcc4.6.2 was optimizing the libpayload alloc() function and failing to
    reload a pointer after the memory had been manipulated by a pointer in
    the inlined function setup(). I changes the pointer type to volatile
    and now pass it to the setup() function. I also cleaned up the
    declaration so that it isn't cast a bunch times in the function.

Change-Id: I1637bd7bd5d9cf82ac88925cbfe76d319aa3cd82
    Signed-off-by: Marc Jones 
---
 payloads/libpayload/libc/malloc.c |   25 +++++++++++--------------
 1 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/payloads/libpayload/libc/malloc.c b/payloads/libpayload/libc/malloc.c
index 6389fc9..9412cab 100644
--- a/payloads/libpayload/libc/malloc.c
+++ b/payloads/libpayload/libc/malloc.c
@@ -73,11 +73,9 @@ static int heap_initialized = 0;
 static int minimal_free = 0;
 #endif

-static void setup(void)
+static void setup(hdrtype_t volatile *start, int size)
 {
-	int size = (unsigned int)(&_eheap - &_heap) - HDRSIZE;
-
-	*((hdrtype_t *) hstart) = FREE_BLOCK(size);
+	*start = FREE_BLOCK(size);

#ifdef CONFIG_DEBUG_MALLOC
    heap_initialized = 1;
@@ -88,7 +86,7 @@ static void setup(void)
 static void *alloc(int len)
 {
    hdrtype_t header;
-	void *ptr = hstart;
+	hdrtype_t volatile *ptr = (hdrtype_t volatile *) hstart;

/* Align the size. */
    len = (len + 3) & ~3;
@@ -97,12 +95,12 @@ static void *alloc(int len)
    	return (void *)NULL;

/* Make sure the region is setup correctly. */
-	if (!HAS_MAGIC(*((hdrtype_t *) ptr)))
-		setup();
+	if (!HAS_MAGIC(*ptr))
+		setup(ptr, len);

/* Find some free space. */
    do {
-		header = *((hdrtype_t *) ptr);
+		header = *ptr;
    	int size = SIZE(header);

if (!HAS_MAGIC(header) || size == 0) {
@@ -114,7 +112,7 @@ static void *alloc(int len)

if (header & FLAG_FREE) {
    		if (len <= size) {
-				void *nptr = ptr + (HDRSIZE + len);
+				hdrtype_t volatile *nptr = ptr + (HDRSIZE + len);
    			int nsize = size - (HDRSIZE + len);

/* If there is still room in this block,
@@ -124,14 +122,13 @@ static void *alloc(int len)

if (nsize > 0) {
    				/* Mark the block as used. */
-					*((hdrtype_t *) ptr) = USED_BLOCK(len);
+					*ptr = USED_BLOCK(len);

/* Create a new free block. */
-					*((hdrtype_t *) nptr) =
-					    FREE_BLOCK(nsize);
+					*nptr = FREE_BLOCK(nsize);
    			} else {
    				/* Mark the block as used. */
-					*((hdrtype_t *) ptr) = USED_BLOCK(size);
+					*ptr = USED_BLOCK(size);
    			}

return (void *)(ptr + HDRSIZE);
@@ -140,7 +137,7 @@ static void *alloc(int len)

ptr += HDRSIZE + size;

-	} while (ptr < hend);
+	} while (ptr < (hdrtype_t *) hend);

/* Nothing available. */
    return (void *)NULL;