[PATCH] aarch64: Add MTE mode tunable

[Wilco Dijkstra]

Hi Yury,

> Isn't this just a template and resolvers don't have to use any of these
> fields?

Not all need to be used, but resolvers use these booleans to select ifuncs.

> In the MTE case, the logic behind GLRO(dl_aarch64_cpu_features).mte and
> GL(dl_aarch64_mte_mode) might be complicated. I don't think it's useful
> to add it to this template.

It shouldn't be if dl_aarch64_mte_mode has been defined properly. Ie. disabled
means disabled and enabled in any mode is only legal if MTE is available.

> Resovlers will need to see both if these fields, but perhaps it would
> help not to define this variable?
>
>  bool __attribute__((unused)) mte

I don't see why they would need both - for string functions we just want to know
whether MTE was enabled. There is no need for adding complex checks when all
we need is a boolean.

Cheers,
Wilco