The arm64 kernel assumes that FP/ASIMD units are always present
and accesses the FP/ASIMD specific registers unconditionally. This
could cause problems when they are absent. This patch adds the
support for kernel handling systems without FP/ASIMD by skipping the
register access within the kernel. For kvm, we trap the accesses
to FP/ASIMD and inject an undefined instruction exception to the VM.
The callers of the exported kernel_neon_begin_partial() should
make sure that the FP/ASIMD is supported.
Cc: Will Deacon <will.deacon@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
[catalin.marinas@arm.com: add comment on the ARM64_HAS_NO_FPSIMD conflict and the new location] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>