Gcc complains if we don't cast this to a struct cpumask pointer.
arch/x86/kernel/nmi_selftest.c:93:2:

	warning: passing argument 1 of ‘cpumask_empty’ from
	incompatible pointer type [enabled by default]
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/20111207110612.GA3437@mwandaSigned-off-by: NIngo Molnar <mingo@elte.hu>

If no remote cpus are online, then just quietly skip the remote
IPI test for now.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: andi@firstfloor.org
Cc: torvalds@linux-foundation.org
Cc: peterz@infradead.org
Cc: robert.richter@amd.com
Link: http://lkml.kernel.org/r/20111206180859.GR1669@redhat.comSigned-off-by: NIngo Molnar <mingo@elte.hu>

The previous patch modified the stop cpus path to use NMI
instead of IRQ as the way to communicate to the other cpus to
shutdown.  There were some concerns that various machines may
have problems with using an NMI IPI.

This patch creates a selftest to check if NMI is working at
boot. The idea is to help catch any issues before the machine
panics and we learn the hard way.

Loosely based on the locking-selftest.c file, this separate file
runs a couple of simple tests and reports the results.  The
output looks like:

...
Brought up 4 CPUs
----------------
| NMI testsuite:
--------------------
  remote IPI:  ok  |
   local IPI:  ok  |
--------------------
Good, all   2 testcases passed! |
---------------------------------
Total of 4 processors activated (21330.61 BogoMIPS).
...
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>
Cc: seiji.aguchi@hds.com
Cc: vgoyal@redhat.com
Cc: mjg@redhat.com
Cc: tony.luck@intel.com
Cc: gong.chen@intel.com
Cc: satoru.moriya@hds.com
Cc: avi@redhat.com
Cc: Andi Kleen <andi@firstfloor.org>
Link: http://lkml.kernel.org/r/1318533267-18880-3-git-send-email-dzickus@redhat.comSigned-off-by: NIngo Molnar <mingo@elte.hu>