[PATCH v4] nptl: Add <thread_pointer.h> for RISC-V

[Florian Weimer]

* Michael Jeanson:

> On 2024-10-17 22:58, Florian Weimer wrote:
>> Sorry, I was confused.  We had some previous discussion about
>> providing a <sys/thread_pointer.h> header, but we never got around
>> installing it.  Installed headers are defined by listing them in the
>> “headers” variable in Makefiles.
>
> If <sys/thread_pointer.h> is still a possibility I think it makes sense
> to apply those constraints to our implementation of <thread_pointer.h>.

I think we might still want to expose <sys/thread_pointer.h> once we
have broader architecture coverage.

> Otherwise the global register variable seems like a cleaner implementation.

We could still use the global register variable approach for glibc
itself.  The wrapper header in include/sys/thread_pointer.h could
redirect things to other headers.  On the other hand, the global
register variable approach will never be fully consistent across
architectures because many just don't have this type of thread pointer
register.