Julius Werner has submitted this change. ( https://review.coreboot.org/c/coreboot/+/47827 )
Change subject: cbfstool: Replace FILENAME_ALIGN 16 with ATTRIBUTE_ALIGN 4 ......................................................................
cbfstool: Replace FILENAME_ALIGN 16 with ATTRIBUTE_ALIGN 4
cbfstool has always had a CBFS_FILENAME_ALIGN that forces the filename field to be aligned upwards to the next 16-byte boundary. This was presumably done to align the file contents (which used to come immediately after the filename field).
However, this hasn't really worked right ever since we introduced CBFS attributes. Attributes come between the filename and the contents, so what this code currently does is fill up the filename field with extra NUL-bytes to the boundary, and then just put the attributes behind it with whatever size they may be. The file contents don't end up with any alignment guarantee and the filename field is just wasting space.
This patch removes the old FILENAME_ALIGN, and instead adds a new alignment of 4 for the attributes. 4 seems like a reasonable alignment to enforce since all existing attributes (with the exception of weird edge cases with the padding attribute) already use sizes divisible by 4 anyway, and the common attribute header fields have a natural alignment of 4. This means file contents will also have a minimum alignment guarantee of 4 -- files requiring a larger guarantee can still be added with the --alignment flag as usual.
Signed-off-by: Julius Werner jwerner@chromium.org Change-Id: I43f3906977094df87fdc283221d8971a6df01b53 Reviewed-on: https://review.coreboot.org/c/coreboot/+/47827 Tested-by: build bot (Jenkins) no-reply@coreboot.org Reviewed-by: Angel Pons th3fanbus@gmail.com Reviewed-by: Aaron Durbin adurbin@chromium.org --- M src/commonlib/bsd/include/commonlib/bsd/cbfs_serialized.h M util/cbfstool/cbfs_image.c M util/cbfstool/cbfstool.c 3 files changed, 7 insertions(+), 6 deletions(-)
Approvals: build bot (Jenkins): Verified Aaron Durbin: Looks good to me, approved Angel Pons: Looks good to me, but someone else must approve
diff --git a/src/commonlib/bsd/include/commonlib/bsd/cbfs_serialized.h b/src/commonlib/bsd/include/commonlib/bsd/cbfs_serialized.h index ac4b38f..dd50469 100644 --- a/src/commonlib/bsd/include/commonlib/bsd/cbfs_serialized.h +++ b/src/commonlib/bsd/include/commonlib/bsd/cbfs_serialized.h @@ -114,6 +114,9 @@ uint8_t data[0]; } __packed;
+/* All attribute sizes must be divisible by this! */ +#define CBFS_ATTRIBUTE_ALIGN 4 + /* Depending on how the header was initialized, it may be backed with 0x00 or * 0xff. Support both. */ enum cbfs_file_attr_tag { diff --git a/util/cbfstool/cbfs_image.c b/util/cbfstool/cbfs_image.c index 0191682..d3c6c94 100644 --- a/util/cbfstool/cbfs_image.c +++ b/util/cbfstool/cbfs_image.c @@ -34,10 +34,6 @@ * removing said guarantees. */
-/* The file name align is not defined in CBFS spec -- only a preference by - * (old) cbfstool. */ -#define CBFS_FILENAME_ALIGN (16) - static const char *lookup_name_by_type(const struct typedesc_t *desc, uint32_t type, const char *default_value) { @@ -70,7 +66,7 @@ size_t cbfs_calculate_file_header_size(const char *name) { return (sizeof(struct cbfs_file) + - align_up(strlen(name) + 1, CBFS_FILENAME_ALIGN)); + align_up(strlen(name) + 1, CBFS_ATTRIBUTE_ALIGN)); }
/* Only call on legacy CBFSes possessing a master header. */ @@ -1870,6 +1866,7 @@ uint32_t tag, uint32_t size) { + assert(IS_ALIGNED(size, CBFS_ATTRIBUTE_ALIGN)); struct cbfs_file_attribute *attr, *next; next = cbfs_file_first_attr(header); do { diff --git a/util/cbfstool/cbfstool.c b/util/cbfstool/cbfstool.c index c7330a4..72c01b9 100644 --- a/util/cbfstool/cbfstool.c +++ b/util/cbfstool/cbfstool.c @@ -751,7 +751,8 @@
if (param.padding) { const uint32_t hs = sizeof(struct cbfs_file_attribute); - uint32_t size = MAX(hs, param.padding); + uint32_t size = ALIGN_UP(MAX(hs, param.padding), + CBFS_ATTRIBUTE_ALIGN); INFO("Padding %d bytes\n", size); struct cbfs_file_attribute *attr = (struct cbfs_file_attribute *)cbfs_add_file_attr(