diff --git a/payloads/libpayload/libc/malloc.c b/payloads/libpayload/libc/malloc.c index 8b22daa9cc..48bf32ee3b 100644 --- a/payloads/libpayload/libc/malloc.c +++ b/payloads/libpayload/libc/malloc.c @@ -123,7 +123,8 @@ int dma_coherent(void *ptr) return !dma_initialized() || (dma->start <= ptr && dma->end > ptr); } -static void *alloc(int len, struct memory_type *type) +/* Find free block of size >= len */ +static hdrtype_t volatile *find_free_block(int len, struct memory_type *type) { hdrtype_t header; hdrtype_t volatile *ptr = (hdrtype_t volatile *)type->start; @@ -156,37 +157,53 @@ static void *alloc(int len, struct memory_type *type) halt(); } - if (header & FLAG_FREE) { - if (len <= size) { - hdrtype_t volatile *nptr = (hdrtype_t volatile *)((uintptr_t)ptr + HDRSIZE + len); - int nsize = size - (HDRSIZE + len); - - /* If there is still room in this block, - * then mark it as such otherwise account - * the whole space for that block. - */ - - if (nsize > 0) { - /* Mark the block as used. */ - *ptr = USED_BLOCK(len); - - /* Create a new free block. */ - *nptr = FREE_BLOCK(nsize); - } else { - /* Mark the block as used. */ - *ptr = USED_BLOCK(size); - } - - return (void *)((uintptr_t)ptr + HDRSIZE); - } - } + if ((header & FLAG_FREE) && len <= size) + return ptr; ptr = (hdrtype_t volatile *)((uintptr_t)ptr + HDRSIZE + size); } while (ptr < (hdrtype_t *) type->end); /* Nothing available. */ - return (void *)NULL; + return NULL; +} + +/* Mark the block with length 'len' as used */ +static void use_block(hdrtype_t volatile *ptr, int len) +{ + /* Align the size. */ + len = ALIGN_UP(len, HDRSIZE); + + hdrtype_t volatile *nptr = (hdrtype_t volatile *) + ((uintptr_t)ptr + HDRSIZE + len); + int size = SIZE(*ptr); + int nsize = size - (HDRSIZE + len); + + /* + * If there is still room in this block, then mark it as such otherwise + * account the whole space for that block. + */ + if (nsize > 0) { + /* Mark the block as used. */ + *ptr = USED_BLOCK(len); + + /* Create a new free block. */ + *nptr = FREE_BLOCK(nsize); + } else { + /* Mark the block as used. */ + *ptr = USED_BLOCK(size); + } +} + +static void *alloc(int len, struct memory_type *type) +{ + hdrtype_t volatile *ptr = find_free_block(len, type); + + if (ptr == NULL) + return NULL; + + use_block(ptr, len); + return (void *)((uintptr_t)ptr + HDRSIZE); } static void _consolidate(struct memory_type *type) @@ -277,6 +294,7 @@ void *calloc(size_t nmemb, size_t size) void *realloc(void *ptr, size_t size) { void *ret, *pptr; + hdrtype_t volatile *block; unsigned int osize; struct memory_type *type = heap; @@ -300,18 +318,23 @@ void *realloc(void *ptr, size_t size) * reallocated the new space. */ free(ptr); - ret = alloc(size, type); + + block = find_free_block(size, type); + if (block == NULL) + return NULL; + + ret = (void *)((uintptr_t)block + HDRSIZE); /* - * if ret == NULL, then doh - failure. - * if ret == ptr then woo-hoo! no copy needed. + * If ret == ptr, then no copy is needed. Otherwise, move the memory to + * the new location, which might be before the old one and overlap since + * the free() above includes a _consolidate(). */ - if (ret == NULL || ret == ptr) - return ret; + if (ret != ptr) + memmove(ret, ptr, osize > size ? size : osize); - /* Move the memory to the new location. Might be before the old location - and overlap since the free() above includes a _consolidate(). */ - memmove(ret, ptr, osize > size ? size : osize); + /* Mark the block as used. */ + use_block(block, size); return ret; }