arm64: assembler: add macros to conditionally yield the NEON under PREEMPT

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Add support macros to conditionally yield the NEON (and thus the CPU)
that may be called from the assembler code.

In some cases, yielding the NEON involves saving and restoring a non
trivial amount of context (especially in the CRC folding algorithms),
and so the macro is split into three, and the code in between is only
executed when the yield path is taken, allowing the context to be preserved.
The third macro takes an optional label argument that marks the resume
path after a yield has been performed.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

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Ard Biesheuvel 2018-03-29 15:13:23 +02:00 • committed by Will Deacon

parent 0f468e221c

commit 24534b3511

2 changed files with 76 additions and 0 deletions

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73

arch/arm64/include/asm/assembler.h

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3

arch/arm64/kernel/asm-offsets.c

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