Pull s390 fixes from Heiko Carstens:
- fix stack unwinder: the stack unwinder rework has on off-by-one bug
which prevents following stack backchains over more than one context
(e.g. irq -> process).
- fix address space detection in exception handler: if user space
switches to access register mode, which is not supported anymore, the
exception handler may resolve to the wrong address space.
* tag 's390-5.2-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/unwind: correct stack switching during unwind
s390/mm: fix address space detection in exception handling