[PATCH] s390: fix in-user atomic futex operation.

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

__futex_atomic_op needs to do an atomic operation in the user address space,
not the kernel address space.  Add the missing sacf 256/sacf 0 to switch to
the secondary mode before doing the compare-and-swap.  In addition add
another fixup for catch specification exceptions if the compare-and-swap
address is not aligned.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>