arm64: insn: Don't assume unrecognized HINTs are skippable

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Currently the kernel assumes that any HINT which it does not explicitly
recognise is skippable.  This is not robust as new instructions may be
added which need special handling, and in any case software should only
be using explicit NOP instructions for deliberate NOPs.

This has the effect of rendering PAC and BTI instructions unprobeable
which means that probes can't be inserted on the first instruction of
functions built with those features.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200504131326.18290-4-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

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Mark Brown 2020-05-04 14:13:25 +01:00 • committed by Will Deacon

parent 07dcd9677c

commit c71052cc9e

1 changed files with 3 additions and 7 deletions

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arch/arm64/kernel/insn.c

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