[PATCH] aarch64: MTE compatible strchrnul

Wilco Dijkstra Wilco.Dijkstra@arm.com
Fri Jun 5 08:45:33 GMT 2020


>> Should we add a marker to indicate that an object file is
>> mte compatible?
> i think we will need a marking for 'compatible with tagged
> pointers' (on aarch64 pointer that's a new opt-in kernel abi
> and user code may use the top byte of pointers) and another
> one for 'compatible with 16byte granules'.
> e.g. the old string asm would have the first marking but not
> the second one.

I don't see how adding different markings would help. String functions
which are not MTE compatible simply cannot be used if MTE is enabled,
and if they are not fixed or ifunced then all of GLIBC is not compatible
with MTE.

Compatibility is a dynamic property, ie. an incompatible string function is
perfectly fine if it is ifunced. So having various different markings is not useful.
Either way all of this is unrelated to these patches.


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