The version that is in there is currently broken from a user-space
perspective (gdb expects u_ar0 to be struct user_regs_struct *, which it
isn't for a bunch of the architectures defined); it *could* be argued
the right thing is to fix it up since it *does* export an ABI
-- specifically, the format of a.out core dumps -- but it is probably
easier to just axe it; userspace has had to deal with this issue on its
own for a long time already.
Acked-by: H. Peter Anvin <firstname.lastname@example.org>