diff options
Diffstat (limited to 'util/cbfstool/cbfs_image.c')
| -rw-r--r-- | util/cbfstool/cbfs_image.c | 54 |
1 files changed, 29 insertions, 25 deletions
diff --git a/util/cbfstool/cbfs_image.c b/util/cbfstool/cbfs_image.c index 1f60d68154..0230d8032e 100644 --- a/util/cbfstool/cbfs_image.c +++ b/util/cbfstool/cbfs_image.c @@ -66,13 +66,6 @@ static const struct typedesc_t types_cbfs_compression[] = { {0, NULL}, }; -static uint32_t align_up(uint32_t value, uint32_t align) -{ - if (value % align) - value += align - (value % align); - return value; -} - static const char *lookup_name_by_type(const struct typedesc_t *desc, uint32_t type, const char *default_value) { @@ -180,6 +173,7 @@ int cbfs_image_create(struct cbfs_image *image, { struct cbfs_header header; struct cbfs_file *entry; + int32_t *rel_offset; uint32_t cbfs_len; size_t entry_header_len; void *header_loc; @@ -207,9 +201,6 @@ int cbfs_image_create(struct cbfs_image *image, "header=0x%x, entries_offset=0x%x\n", bootblock_offset, header_offset, entries_offset); - if (align == 0) - align = 64; // default align size. - // Prepare bootblock if (bootblock_offset + bootblock->size > size) { ERROR("Bootblock (0x%x+0x%zx) exceed ROM size (0x%zx)\n", @@ -226,7 +217,7 @@ int cbfs_image_create(struct cbfs_image *image, bootblock->size); // Prepare header - if (header_offset + sizeof(header) > size) { + if (header_offset + sizeof(header) > size - sizeof(int32_t)) { ERROR("Header (0x%x+0x%zx) exceed ROM size (0x%zx)\n", header_offset, sizeof(header), size); return -1; @@ -242,6 +233,14 @@ int cbfs_image_create(struct cbfs_image *image, header_loc = (image->buffer.data + header_offset); cbfs_put_header(header_loc, image->header); + // The last 4 byte of the image contain the relative offset from the end + // of the image to the master header as a 32-bit signed integer. x86 + // relies on this also being its (memory-mapped, top-aligned) absolute + // 32-bit address by virtue of how two's complement numbers work. + assert(size % sizeof(int32_t) == 0); + rel_offset = (int32_t *)(image->buffer.data + size - sizeof(int32_t)); + *rel_offset = header_offset - size; + // Prepare entries if (align_up(entries_offset, align) != entries_offset) { ERROR("Offset (0x%x) must be aligned to 0x%x.\n", @@ -256,8 +255,8 @@ int cbfs_image_create(struct cbfs_image *image, } entry = (struct cbfs_file *)(image->buffer.data + entries_offset); // To calculate available length, find - // e = min(bootblock, header, size) where e > entries_offset. - cbfs_len = size; + // e = min(bootblock, header, rel_offset) where e > entries_offset. + cbfs_len = size - sizeof(int32_t); if (bootblock_offset > entries_offset && bootblock_offset < cbfs_len) cbfs_len = bootblock_offset; if (header_offset > entries_offset && header_offset < cbfs_len) @@ -772,17 +771,21 @@ struct cbfs_header *cbfs_find_header(char *data, size_t size) { size_t offset; int found = 0; - uint32_t x86sig; + int32_t rel_offset; struct cbfs_header *header, *result = NULL; - // Try x86 style (check signature in bottom) header first. - x86sig = *(uint32_t *)(data + size - sizeof(uint32_t)); - offset = (x86sig + (uint32_t)size); - DEBUG("x86sig: 0x%x, offset: 0x%zx\n", x86sig, offset); + // Try finding relative offset of master header at end of file first. + rel_offset = *(int32_t *)(data + size - sizeof(int32_t)); + offset = size + rel_offset; + DEBUG("relative offset: %#zx(-%#zx), offset: %#zx\n", + (size_t)rel_offset, (size_t)-rel_offset, offset); if (offset >= size - sizeof(*header) || ntohl(((struct cbfs_header *)(data + offset))->magic) != - CBFS_HEADER_MAGIC) + CBFS_HEADER_MAGIC) { + // Some use cases append non-CBFS data to the end of the ROM. + DEBUG("relative offset seems wrong, scanning whole image...\n"); offset = 0; + } for (; offset + sizeof(*header) < size; offset++) { header = (struct cbfs_header *)(data + offset); @@ -793,14 +796,15 @@ struct cbfs_header *cbfs_find_header(char *data, size_t size) // Probably not a real CBFS header? continue; } - found++; - result = header; + if (!found++) + result = header; } - if (found > 1) { - ERROR("multiple (%d) CBFS headers found!\n", + if (found > 1) + // Top-aligned images usually have a working relative offset + // field, so this is more likely to happen on bottom-aligned + // ones (where the first header is the "outermost" one) + WARN("Multiple (%d) CBFS headers found, using the first one.\n", found); - result = NULL; - } return result; } |