These new-style firmware images use the FMAP of the root of knowledge
about their layout, which allows them to have sections containing raw
data whose offset and size can easily be determined at runtime or when
modifying or flashing the image. Furthermore, they can even have
multiple CBFSes, each of which occupies a different FMAP region. It is
assumed that the first entry of each CBFS, including the primary one,
will be located right at the start of its region. This means that the
bootblock needs to be moved into its own FMAP region, but makes the
CBFS master header obsolete because, with the exception of the version
and alignment, all its fields are redundant once its CBFS has an entry
in the FMAP. The version code will be addressed in a future commit
before the new format comes into use, while the alignment will just be
defined to 64 bytes in both cbfstool and coreboot itself, since
there's almost no reason to ever change it in practice. The version
code field and all necessary coreboot changes will come separately.
BUG=chromium:470407
TEST=Build panther and nyan_big coreboot.rom and image.bin images with
and without this patch, diff their hexdumps, and note that no
locations differ except for those that do between subsequent builds of
the same codebase. Try working with new-style images: use fmaptool to
produce an FMAP section from an fmd file having raw sections and
multiple CBFSes, pass the resulting file to cbfstool create -M -F,
then try printing its layout and CBFSes' contents, add and remove CBFS
files, and read and write raw sections.
BRANCH=None
Change-Id: I7dd2578d2143d0cedd652fdba5b22221fcc2184a
Signed-off-by: Sol Boucher <solb@chromium.org>
Original-Commit-Id: 8a670322297f83135b929a5b20ff2bd0e7d2abd3
Original-Change-Id: Ib86fb50edc66632f4e6f717909bbe4efb6c874e5
Original-Signed-off-by: Sol Boucher <solb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/265863
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10135
Tested-by: build bot (Jenkins)
67a0a864be