tree c38b103ddc555e36b8c009dc7d0c3f7f52fffa07
parent 7a92e3895f84daab1c9051eede1d8a33446321a5
author Nikolai Vyssotski <nikolai.vyssotski@amd.corp-partner.google.com> 1613089543 -0600
committer Martin Roth <martinroth@google.com> 1613582107 +0000

drivers/intel/fsp2_0: Allow larger FSPS UPD than expected in coreboot

Enforcing the exact match of FSPS UPD block size between FSP and
coreboot mandates simultaneous updates to coreboot and FSP repos. Allow
coreboot to proceed if its UPD structure is smaller than FSP one. This
usually indicates that FSPS has an updated (larger) UPD structure which
should be soon matched/updated on the coreboot side to keep them in
sync.

While this is an undesirable situation that should be corrected
ASAP, it is safe from coreboot perspective. It is safe (as long as
default values in FSP UPD are sane enough to boot) because FSPS UPD
buffer is allocated on the heap with the size specified in FSPS
(larger) and filled with FSPS default values. This allows FSP UPD
changes to be submitted first followed by changes in coreboot repo.

Note that this only applies to the case when entire FSPS UPD structure
grows which should be rare as FSP should allocate enough reserve space,
anticipating future expansion, to keep the structure from growing when
new members are added.

BUG=b:171234996
BRANCH=Zork
TEST=build Trembyle

Change-Id: I557fd3a1f208b5b444ccf76e1552e74ecf4decad
Signed-off-by: Nikolai Vyssotski <nikolai.vyssotski@amd.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50576
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Martin Roth <martinroth@google.com>