[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, Felix Singer, Julius Werner, Lean Sheng Tan, Martin L Roth, Nico Huber, ron minnich.

David Milosevic has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/74798?usp=email )

Change subject: arch/arm64: Add EL1/EL2/EL3 support for arm64
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Patch Set 9:

(3 comments)

File src/arch/arm64/Kconfig:

https://review.coreboot.org/c/coreboot/+/74798/comment/6c8af8a9_0ed23f4a :
PS6, Line 30: 1 (EL1), 2 (EL2) and 3 (EL3)
> These are standard Arm architectural terms (like "CPL0" on x86), I don't think we need to add more e […]

Done

https://review.coreboot.org/c/coreboot/+/74798/comment/7ca08d1b_81303cc7 :
PS6, Line 41: 	depends on ARCH_RAMSTAGE_ARM64
> May want to add a `depends on ARM64_CURRENT_EL == 3` here, since this wouldn't work for other levels […]

Done

File src/arch/arm64/armv8/cpu.S:

https://review.coreboot.org/c/coreboot/+/74798/comment/2611b168_8cc4fc94 :
PS6, Line 87: #endif
> Doing this everywhere looks pretty ugly. Can we add a macro like […]

Done