The EAC1 release of the SME specification adds the FA64 feature which
requires enablement at higher ELs before lower ELs can use it. Document
what we require from higher ELs in our boot requirements.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211026111802.12853-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
- SMCR_EL2.LEN must be initialised to the same value for all CPUs the
kernel will execute on.
+ For CPUs with the Scalable Matrix Extension FA64 feature (FEAT_SME_FA64)
+
+ - If EL3 is present:
+
+ - SMCR_EL3.FA64 (bit 31) must be initialised to 0b1.
+
+ - If the kernel is entered at EL1 and EL2 is present:
+
+ - SMCR_EL2.FA64 (bit 31) must be initialised to 0b1.
+
The requirements described above for CPU mode, caches, MMUs, architected
timers, coherency and system registers apply to all CPUs. All CPUs must
enter the kernel in the same exception level. Where the values documented