arm64: Support systems without FP/ASIMD
authorSuzuki K Poulose <suzuki.poulose@arm.com>
Tue, 8 Nov 2016 13:56:21 +0000 (13:56 +0000)
committerCatalin Marinas <catalin.marinas@arm.com>
Wed, 16 Nov 2016 18:05:10 +0000 (18:05 +0000)
commit82e0191a1aa11abfddb22c8944989b7735560efc
tree192b21e7191e2385dc4a58f0562fff4a2f5f68b4
parenta4023f682739439b434165b54af7cb3676a4766e
arm64: Support systems without FP/ASIMD

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>
arch/arm64/include/asm/cpufeature.h
arch/arm64/include/asm/neon.h
arch/arm64/kernel/cpufeature.c
arch/arm64/kernel/fpsimd.c
arch/arm64/kvm/handle_exit.c
arch/arm64/kvm/hyp/hyp-entry.S
arch/arm64/kvm/hyp/switch.c