libpayload: dma_malloc: Prevent warm reboot problems and add debugging

Since the DMA memory is allocated by Coreboot (outside of the payload's
linker script), it won't get zeroed upon loading like the heap.
Therefore, a warm reboot that doesn't reset memory may leave stale
malloc cookies lying around and misinterpret them as memory that is
still in use on the next boot. After several boots this may fill up the
whole DMA memory and lead to OOM conditions.

Therefore, this patch explicitly wipes the first cookie in
init_dma_memory() to prevent that from happening. It also expands the
existing memory allocator debugging code to cover the DMA parts, which
was very helpful in identifying this particular problem.

Change-Id: I6e2083c286ff8ec865b22dd922c39c456944b451
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/169455
Reviewed-by: Stefan Reinauer <reinauer@google.com>
(cherry picked from commit 8e5e1784638563b865553125cd5dab1d36a5d2cb)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6645
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

1 files changed, 55 insertions, 34 deletions

diff --git a/payloads/libpayload/libc/malloc.c b/payloads/libpayload/libc/malloc.c
index 11dfeefadd..0f2845d4ea 100644
--- a/payloads/libpayload/libc/malloc.c
+++ b/payloads/libpayload/libc/malloc.c
@@ -46,11 +46,21 @@ struct memory_type {
 	void *start;
 	void *end;
 	struct align_region_t* align_regions;
+#ifdef CONFIG_LP_DEBUG_MALLOC
+	int magic_initialized;
+	size_t minimal_free;
+	const char *name;
+#endif
 };
 
 extern char _heap, _eheap;	/* Defined in the ldscript. */
 
-static struct memory_type default_type = { (void *)&_heap, (void *)&_eheap, NULL };
+static struct memory_type default_type =
+	{ (void *)&_heap, (void *)&_eheap, NULL
+#ifdef CONFIG_LP_DEBUG_MALLOC
+	, 0, 0, "HEAP"
+#endif
+	};
 static struct memory_type *const heap = &default_type;
 static struct memory_type *dma = &default_type;
 
@@ -75,26 +85,31 @@ typedef u64 hdrtype_t;
 static int free_aligned(void* addr, struct memory_type *type);
 void print_malloc_map(void);
 
-#ifdef CONFIG_LP_DEBUG_MALLOC
-static int heap_initialized = 0;
-static int minimal_free = 0;
-#endif
-
 void init_dma_memory(void *start, u32 size)
 {
-#ifdef CONFIG_LP_DEBUG_MALLOC
 	if (dma_initialized()) {
-		printf("WARNING: %s called twice!\n");
+		printf("ERROR: %s called twice!\n", __func__);
 		return;
 	}
 
-	printf("Initializing cache-coherent DMA memory at [%p:%p]\n", start, start + size);
-#endif
+	/*
+	 * DMA memory might not be zeroed by Coreboot on stage loading, so make
+	 * sure we clear the magic cookie from last boot.
+	 */
+	*(hdrtype_t *)start = 0;
 
 	dma = malloc(sizeof(*dma));
 	dma->start = start;
 	dma->end = start + size;
 	dma->align_regions = NULL;
+
+#ifdef CONFIG_LP_DEBUG_MALLOC
+	dma->minimal_free = 0;
+	dma->magic_initialized = 0;
+	dma->name = "DMA";
+
+	printf("Initialized cache-coherent DMA memory at [%p:%p]\n", start, start + size);
+#endif
 }
 
 int dma_initialized()
@@ -108,16 +123,6 @@ int dma_coherent(void *ptr)
 	return !dma_initialized() || (dma->start <= ptr && dma->end > ptr);
 }
 
-static void setup(hdrtype_t volatile *start, int size)
-{
-	*start = FREE_BLOCK(size);
-
-#ifdef CONFIG_LP_DEBUG_MALLOC
-	heap_initialized = 1;
-	minimal_free  = size;
-#endif
-}
-
 static void *alloc(int len, struct memory_type *type)
 {
 	hdrtype_t header;
@@ -130,8 +135,14 @@ static void *alloc(int len, struct memory_type *type)
 		return (void *)NULL;
 
 	/* Make sure the region is setup correctly. */
-	if (!HAS_MAGIC(*ptr))
-		setup(ptr, (int)((type->end - type->start) - HDRSIZE));
+	if (!HAS_MAGIC(*ptr)) {
+		size_t size = (type->end - type->start) - HDRSIZE;
+		*ptr = FREE_BLOCK(size);
+#ifdef CONFIG_LP_DEBUG_MALLOC
+		type->magic_initialized = 1;
+		type->minimal_free = size;
+#endif
+	}
 
 	/* Find some free space. */
 	do {
@@ -452,24 +463,29 @@ void *dma_memalign(size_t align, size_t size)
 #ifdef CONFIG_LP_DEBUG_MALLOC
 void print_malloc_map(void)
 {
-	void *ptr = heap->start;
-	int free_memory = 0;
+	struct memory_type *type = heap;
+	void *ptr;
+	int free_memory;
 
-	while (ptr < heap->end) {
+again:
+	ptr = type->start;
+	free_memory = 0;
+
+	while (ptr < type->end) {
 		hdrtype_t hdr = *((hdrtype_t *) ptr);
 
 		if (!HAS_MAGIC(hdr)) {
-			if (heap_initialized)
-				printf("Poisoned magic - we're toast\n");
+			if (type->magic_initialized)
+				printf("%s: Poisoned magic - we're toast\n", type->name);
 			else
-				printf("No magic yet - going to initialize\n");
+				printf("%s: No magic yet - going to initialize\n", type->name);
 			break;
 		}
 
 		/* FIXME: Verify the size of the block. */
 
-		printf("%x: %s (%x bytes)\n",
-		       (unsigned int)(ptr - heap->start),
+		printf("%s %x: %s (%x bytes)\n", type->name,
+		       (unsigned int)(ptr - type->start),
 		       hdr & FLAG_FREE ? "FREE" : "USED", SIZE(hdr));
 
 		if (hdr & FLAG_FREE)
@@ -478,9 +494,14 @@ void print_malloc_map(void)
 		ptr += HDRSIZE + SIZE(hdr);
 	}
 
-	if (free_memory && (minimal_free > free_memory))
-		minimal_free = free_memory;
-	printf("Maximum memory consumption: %d bytes\n",
-		(unsigned int)(heap->end - heap->start) - HDRSIZE - minimal_free);
+	if (free_memory && (type->minimal_free > free_memory))
+		type->minimal_free = free_memory;
+	printf("%s: Maximum memory consumption: %u bytes\n", type->name,
+		(type->end - type->start) - HDRSIZE - type->minimal_free);
+
+	if (type != dma) {
+		type = dma;
+		goto again;
+	}
 }
 #endif