s390 user_regset/utrace arch work

[Roland McGrath]

> I think I got all the technical issues resolved. The patch below adds
> the required user_regset definitions and core dumps of 64/31 bit
> processes work as expected. I'll add the patch to the git390 patch
> queue.

The compat get/set functions look wrong.  They need to use compat_ulong_t
(i.e. u32) where they use unsigned long and use __{peek,poke}_user_compat
where they use __{peek,poke}_user.  You changed the one case (of four) that
you could actually test, which is the one used by 32-bit core dumps.

> And thanks a lot for the detailed list of things to do. That helped a
> lot to speed up the implementation work.

Glad to help!


Thanks,
Roland