[coreboot-gerrit] Change in coreboot[master]: cpu/x86/smm: Add sinkhole mitigation to relocatable smmstub

[Arthur Heymans (Code Review)]

Hello Aaron Durbin, build bot (Jenkins), Patrick Georgi, Martin Roth,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/37289

to look at the new patch set (#5).

Change subject: cpu/x86/smm: Add sinkhole mitigation to relocatable smmstub
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cpu/x86/smm: Add sinkhole mitigation to relocatable smmstub

This adds a check for LAPIC base twice. There is a very early check
when the CPU is still executing in real mode checks if the LAPIC base
is inside the region [smmbase,smmbase + SMM_DEFAULT_SIZE). The CPU
cannot use anything but a hardcoded size since even accessing the
relocatable parameters is impossible in the state of the CPU.
After the CPU operates in protected mode the relocatable parameters
are accessible and are used the check for the full smm region.

Change-Id: I49927c4f4218552b732bac8aae551d845ad7f079
Signed-off-by: Arthur Heymans 
---
M src/cpu/x86/smm/smm_stub.S
1 file changed, 49 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/89/37289/5