powerpc fixes for 4.13 #6

All fixes for code that went in this cycle.

 - A revert of an optimisation to the syscall exit path, which could lead to an
   oops on either older machines or machines with > 1T of memory.
 - Disable some deep idle states if the firmware configuration for them fails.
 - Re-enable HARD/SOFT lockup detectors in defconfigs after a Kconfig change.
 - Six fairly small patches fixing bugs in our new watchdog code.

Thanks to:
  Gautham R. Shenoy, Nicholas Piggin.
powerpc/watchdog: add locking around init/exit functions

When CPUs start and stop the watchdog, they manipulate shared data
that is normally protected by the lock. Other CPUs can be running
concurrently at this time, so it's a good idea to use locking here
to be on the safe side.

Remove the barrier which is undocumented and didn't do anything.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
1 file changed