arm64: Support systems without FP/ASIMD

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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>

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This commit is contained in:

Suzuki K Poulose 2016-11-08 13:56:21 +00:00 • committed by Catalin Marinas

parent a4023f6827

commit 82e0191a1a

7 changed files with 65 additions and 4 deletions

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12

arch/arm64/include/asm/cpufeature.h

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3

arch/arm64/include/asm/neon.h

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15

arch/arm64/kernel/cpufeature.c

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14

arch/arm64/kernel/fpsimd.c

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11

arch/arm64/kvm/handle_exit.c

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9

arch/arm64/kvm/hyp/hyp-entry.S

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5

arch/arm64/kvm/hyp/switch.c

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