arm64: cpufeature: treat unknown fields as RES0
Any fields not defined in an arm64_ftr_bits entry are propagated to the system-wide register value in init_cpu_ftr_reg(), and while we require that these strictly match for the sanity checks, we don't update them in update_cpu_ftr_reg(). Generally, the lack of an arm64_ftr_bits entry indicates that the bits are currently RES0 (as is the case for the upper 32 bits of all supposedly 32-bit registers). A better default would be to use zero for the system-wide value of unallocated bits, making all register checking consistent, and allowing for subsequent simplifications to the arm64_ftr_bits arrays. This patch updates init_cpu_ftr_reg() to treat unallocated bits as RES0 for the purpose of the system-wide safe value. These bits will still be sanity checked with strict match requirements, as is currently the case. Signed-off-by: NMark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Reviewed-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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