Skip regions locked via flash descriptor for Intel platforms
This patch will prevent flashrom from attempting to read / erase /
write forbidden regions. Instead, it will "fake it". When a read
is performed on a write-only region, the gaps will return as 0xff
bytes. Erase/write operations performed on read-only regions will
be ignored.
Hopefully this approach can be extended to gracefully handle normal
SPI ROM block protect schemes.
Caveats:
1. This does not (yet) deal with region boundaries that are unaligned
to block boundaries. For example, if region 0x1800-0x3000 are
write-protected, flashrom may still erase an entire 4K block
ranging from 0x1000 to 0x1fff and will fail to write valid data to
0x1800-0x1fff.
2. Verification is not entirely truthful. For one, it cannot verify
regions which are unreadable (e.g. ME region). Also, differences
between user-provided file and ROM content in read-only regions
will cause annoying problems because it will appear inconsistent.
BUG=chrome-os-partner:6748
TEST=Tested on Stumpy with read-only descriptor and locked ME region
Change-Id: I004cc9de15d115368261efbb4835622aedfadea0
Reviewed-on: https://gerrit.chromium.org/gerrit/12117
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
7 files changed
