[coreboot-gerrit] [M] Change in coreboot[main]: arch/arm64: Add EL1/EL2/EL3 support for arm64

[David Milosevic (Code Review)]

Attention is currently required from: Angel Pons, Arthur Heymans, Christian Walter, David Milosevic, Felix Singer, Julius Werner, Lean Sheng Tan, Martin L Roth, Nico Huber, ron minnich.

Hello Arthur Heymans, Christian Walter, Felix Singer, Julius Werner, Lean Sheng Tan, Maximilian Brune, build bot (Jenkins), ron minnich,

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

https://review.coreboot.org/c/coreboot/+/74798?usp=email

to look at the new patch set (#13).

The following approvals got outdated and were removed:
Verified+1 by build bot (Jenkins)

Change subject: arch/arm64: Add EL1/EL2/EL3 support for arm64
......................................................................

arch/arm64: Add EL1/EL2/EL3 support for arm64

Currently, arch/arm64 requires coreboot to run on EL3 due
to EL3 register access. This might be an issue when, for example,
one boots into TF-A first and drops into EL2 for coreboot afterwards.

This patch aims at making arch/arm64 more versatile by removing the
current EL3 constraint and allowing arm64 coreboot to run on EL1,
EL2 and EL3.

The strategy here, is to add a Kconfig option (ARM64_CURRENT_EL) which
lets us specify coreboot's EL upon entry. Based on that, we access the
appropriate ELx registers. So, for example, when running coreboot on
EL1, we would not access vbar_el3 or vbar_el2 but instead vbar_el1.
This way, we don't generate faults when accessing higher-EL registers.

Currently only tested on the qemu-aarch64 target. Exceptions were
tested by enabling FATAL_ASSERTS.

Signed-off-by: David Milosevic 
Change-Id: Iae1c57f0846c8d0585384f7e54102a837e701e7e
---
M src/arch/arm64/Kconfig
M src/arch/arm64/armv8/cache.c
M src/arch/arm64/armv8/cpu.S
M src/arch/arm64/armv8/exception.c
M src/arch/arm64/armv8/mmu.c
M src/arch/arm64/boot.c
M src/arch/arm64/include/armv8/arch/cache.h
M src/arch/arm64/include/armv8/arch/lib_helpers.h
M src/arch/arm64/ramdetect.c
M src/arch/arm64/transition.c
M src/arch/arm64/transition_asm.S
11 files changed, 142 insertions(+), 30 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/98/74798/13