soc/intel/common: Apply Intel recommendation for early ramtop caching

Configuring the Early Caching Ramtop range as Write-Back (WB) before
memory initialization is NOT RECOMMENDED. Speculative execution within
this WB range can lead to issues. WB configuration should be applied
to this range ONLY AFTER memory initialization is complete.

To enable Ramtop caching before memory initialization, use
Write-Combining (WC) instead of Write-Back (WB).

This change applies the recommendation by always configuring the early
ramtop caching range as WC.

BUG=b:373290479
TEST=Able to build and boot google/trulo.

Change-Id: Idf6f0be1bc0daa8037ea9c52932eb72434156071
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/85027
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: V Sowmya <v.sowmya@intel.com>
Reviewed-by: Dinesh Gehlot <digehlot@google.com>

0 files changed, 0 insertions, 0 deletions