Hung-Te Lin has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/35612 )
Change subject: mb/google/kukui: Extend FMAP to 8MB layout ......................................................................
Patch Set 7:
(3 comments)
https://review.coreboot.org/c/coreboot/+/35612/6/src/mainboard/google/kukui/... File src/mainboard/google/kukui/chromeos.fmd:
https://review.coreboot.org/c/coreboot/+/35612/6/src/mainboard/google/kukui/... PS6, Line 40: RW_SHARED 36K {
That is... very odd. […]
I tried again and still failed. Here's my change:
RW_SHARED { SHARED_DATA 4K } RW_LEGACY(CBFS)
And here's build failure:
FMAP build-jacuzzi/util/cbfstool/fmaptool -h build-jacuzzi/fmap_config.h build-jacuzzi/fmap.fmd build-jacuzzi/fmap.fmap E: Cannot determine either offset or size of section 'RW_LEGACY' FATAL: Failed while processing provided descriptor
https://review.coreboot.org/c/coreboot/+/35612/6/src/mainboard/google/kukui/... PS6, Line 42: RW_UNUSED
It does? I'm pretty sure it doesn't, anymore. […]
Sorry that was actually "Recovery", and not A/B AU. Already documented that in the fmd (not SHARED_DATA, it's RW_SHARED).
On x86 the RW_SHARED used to contain also DEF_CFG, RW_ENVIRONMENT, VBLOCK_DEV. It's probably true SHARED_DATA is probably useless now, but since the firmware updater is still having the logic (update the block on recovery), I'd like to keep it noted properly.
https://review.coreboot.org/c/coreboot/+/35612/6/src/mainboard/google/kukui/... PS6, Line 44: RW_LEGACY(CBFS) 1M # Minimal 1M.
Not quite sure what you mean here? (It's just a CBFS, it should be able to deal with being bigger or […]
The firmware updater used to have a logic on preserving sections "if the new size is smaller, drop the contents" so I'd like the regions being in known sizes so I can be more sure about that will happen if we decide to move or resize them.
Meanwhile, having an explicit "1M" also helps to ensure "this won't be less than 1M". Otherwise someone modifying RW_SHARED may accidentally consumed too much data and ate the space for RW_LEGACY.