arm64: mte: Allow user control of the generated random tags via prctl()

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The IRG, ADDG and SUBG instructions insert a random tag in the resulting
address. Certain tags can be excluded via the GCR_EL1.Exclude bitmap
when, for example, the user wants a certain colour for freed buffers.
Since the GCR_EL1 register is not accessible at EL0, extend the
prctl(PR_SET_TAGGED_ADDR_CTRL) interface to include a 16-bit field in
the first argument for controlling which tags can be generated by the
above instruction (an include rather than exclude mask). Note that by
default all non-zero tags are excluded. This setting is per-thread.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>

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This commit is contained in:

Catalin Marinas 2019-12-10 11:19:15 +00:00

parent 1c101da8b9

commit af5ce95282

5 changed files with 44 additions and 4 deletions

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1

arch/arm64/include/asm/processor.h

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7

arch/arm64/include/asm/sysreg.h

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35

arch/arm64/kernel/mte.c

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2

arch/arm64/kernel/process.c

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3

include/uapi/linux/prctl.h

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