| commit | 63f6035486a29a78b552f91d102f30557f841018 | [log] [tgz] |
|---|---|---|
| author | Hsuan Ting Chen <[email protected]> | Mon Dec 16 11:11:10 2024 |
| committer | Chromeos LUCI <[email protected]> | Wed Feb 12 09:33:57 2025 |
| tree | 6bc663191b672208c234521e5acad119b770f822 | |
| parent | 255db4276448491a4dc87383ba3dc6c5fce56cdc [diff] |
imports: Make imports/ follow Chromium flashrom This commit makes ap_wpsr follow the Chromium flashrom instead of following the upstream flashrom database. This addresses inconsistencies between the ap_wpsr and flashrom databases, which have led to issues like the one described in b/340421736 in nissa factory branch. This change simplifies development and reduces the risk of introducing regressions when updating the flashrom databases, especially for factory branches. This change is intended to affect the main branch only, there will be further changes related to modify the ap_wpsr imports/ in other factory branches. Imported from flashrom snapshot: b243d7fffc9885d18072f3e27ec2ebbd662101ba BUG=b:362686439 TEST=change to ToT, diff the ap_wpsr and flashrom databases. Cq-Depend: chromium:5808523 Cq-Depend: chromium:6017465 Cq-Depend: chromium:6017466 Cq-Depend: chromium:6005886 Cq-Depend: chromium:6011519 Cq-Depend: chromium:6022541 Change-Id: I888b4e21a900175be41f191c6c8f6dbe8399702e Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/ap_wpsr/+/6096941 Tested-by: Hsuan Ting Chen <[email protected]> Reviewed-by: Jian-Jia Su <[email protected]> Commit-Queue: Hsuan Ting Chen <[email protected]>
The ap_wpsr tool was built to address specific requirements of AP RO verification that intends to measure SR contents for invariance after signature validation.
The tool leverages the flashrom SPI flash chips database to produce theoretical mask,value pairs for a given WP configuration (i.e. protection range start and length) and flash chip part name.
There are however some limitations. While the tool is pure logic (no side-effects) and intended to calculate values with reasonable fidelity there could however be inaccuracies.
These inaccuracies can be the result of any combination of the following factors:
A precise flash chip name is required to be cited physically on what chip is being worked with (and not via probing or other inferences). This precise name needs to be mapped to the corresponding name within the database to produce the tool output products. The output products must be cross-validated with the datasheet to ensure the products are consistent with expectations and any errors in the database are corrected with a patch back to the canonical flashrom flashchips database upstream.
An example usage could be ./ap_wpsr -n "W25Q128.V" -s 0x40000 -l 0xFC0000.
The ap_wpsr tool needs to be given the name of the flashrom chip entry to use for calculating mask,value pairs. This name may not match the vendor name, for example the chip “W25Q128FVSIG” corresponds to a flashrom entry called “W25Q128.V”.
These steps should be followed to find the flashrom chip name for your chip:
-n option.There are two key parts to the tool imports/ and shim/. The shim/ directory just contains enough symbols to allow linking of the imports/ source taken from upstream flashrom. The imports/ contains two key ingredients - the chip database and the writeprotection calculation code. These should be kept up to date by importing fresh copies from flashrom.