The ACPI RSDP can only be found in: - legacy BIOS region - via UEFI service On some systems like ARM that legacy BIOS region is not an option, so to avoid needing UEFI it makes sense to expose the RSDP via a coreboot table entry. This also adds the respective unit test. Change-Id: I591312a2c48f0cbbb03b2787e4b365e9c932afff Signed-off-by: Arthur Heymans <arthur@aheymans.xyz> Reviewed-on: https://review.coreboot.org/c/coreboot/+/62573 Reviewed-by: Lance Zhao Reviewed-by: Angel Pons <th3fanbus@gmail.com> Reviewed-by: Nico Huber <nico.h@gmx.de> Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>