Catalin Marinas af5ce95282 arm64: mte: Allow user control of the generated random tags via prctl() ...

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>

2020-09-04 12:46:07 +01:00

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