tree 699f4cf1a0f2da74a8ec27f5619443fe986ce33c
parent d947639a486beef26b8daa164e3e3832196903c9
author Jeremy Compostella <jeremy.compostella@intel.com> 1697595521 -0700
committer Subrata Banik <subratabanik@google.com> 1697824306 +0000

cpu/intel/common: Define build time physical address reserved bits

According the Intel Software Developer Manual,
CPUID.80000008H:EAX[15:8] reports the physical-address width supported
by the processor.  Unfortunately, it does not necessarily reflect the
physical-address space the system can actulally use as some of those
bits can be reserved for internal hardware use.

It is critical for coreboot to know the actual physical address size.
Overestimating this size can lead to device resource overlaps due to
the hardware ignoring upper reserved bits.  On rex for instance, it
creates some reboot hangs due to an overlap between thunderbolt and
Input Output Manager (IOM) address space.

As some SoCs, such as Meteor Lake, have physical address reserved bits
which cannot be probed at runtime, this commit introduces
`CPU_INTEL_COMMON_RESERVED_PHYS_ADDR_BITS' Kconfig to set the number
of physical address reserved bits at compilation time for those SoCs.

A runtime detection by hardware probing will be attempted if the value
is 0 (default).

BUG=b:288978352

Change-Id: I8748fa3e5bdfd339e973d562c5a201d5616f813e
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78451
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>