Armv8.4-A extension enables MRS instruction encodings inside ESR_ELx.ISS
during exception class ESR_ELx_EC_SYS64 (0x18). This encoding can be used
to emulate MRS instructions which can avoid fetch/decode from user space
thus improving performance. This adds a new sys64_hook structure element
with applicable ESR mask/value pair for MRS instructions on various system
registers but constrained by sysreg encodings which is currently allowed
to be emulated.
Reviewed-by: NSuzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>