[PATCH] aarch64: MTE compatible strchrnul

[Szabolcs Nagy]

The 06/03/2020 17:04, Florian Weimer via Libc-alpha wrote:
> * Adhemerval Zanella via Libc-alpha:
> 
> > Afaiu there is no need to add any marking for MTE, the main difference
> > it enforce 16-byte granularity read. I think you are confusing with
> > BTI, which does require the GNU note.
> 
> If there is no compatibility issue, then why are these changes to the
> glibc string functions needed?
> 
> Clearly I'm confused.

string functions have problem (2): they assume that
if an address is accessible then everything on that
page is accessible via the same pointer (which
is no longer true with mte).

i think we can add the mte-safe string functions and
tackle the abi compatibility issues separately: if
we introduce mte-safe markups we will have to add
that to all asm code to make libc.so marked.
(which will be tricky since we have non-mte-safe
ifunc variants that are only selected on non-mte hw
so the code is not safe but way it is used is safe)