arm64: Implement array_index_mask_nospec()

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Commit 022620eed3 upstream.

Provide an optimised, assembly implementation of array_index_mask_nospec()
for arm64 so that the compiler is not in a position to transform the code
in ways which affect its ability to inhibit speculation (e.g. by introducing
conditional branches).

This is similar to the sequence used by x86, modulo architectural differences
in the carry/borrow flags.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Robin Murphy 2018-02-05 15:34:17 +00:00 • committed by Greg Kroah-Hartman

parent 6afdaf109c

commit 0a532ea3ef

1 changed files with 21 additions and 0 deletions

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arch/arm64/include/asm/barrier.h

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