more s390 updates for 5.19 merge window

- Add Eric Farman as maintainer for s390 virtio drivers.

- Improve machine check handling, and avoid incorrectly injecting a machine
  check into a kvm guest.

- Add cond_resched() call to gmap page table walker in order to avoid
  possible huge latencies. Also use non-quiesing sske instruction to speed
  up storage key handling.

- Add __GFP_NORETRY to KEXEC_CONTROL_MEMORY_GFP so s390 behaves similar like
  common code.

- Get sie control block address from correct stack slot in perf event
  code. This fixes potential random memory accesses.

- Change uaccess code so that the exception handler sets the result of
  get_user() and __get_kernel_nofault() to zero in case of a fault. Until
  now this was done via input parameters for inline assemblies. Doing it
  via fault handling is what most or even all other architectures are
  doing.

- Couple of other small cleanups and fixes.
s390/stack: add union to reflect kvm stack slot usages

Add a union which describes how the empty stack slots are being used
by kvm and perf. This should help to avoid another bug like the one
which was fixed with commit c9bfb460c3e4 ("s390/perf: obtain sie_block
from the right address").

Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Tested-by: Nico Boehr <nrb@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
3 files changed