[SPARC64]: Provide mmu statistics via sysfs.

If the system supports hypervisor based statistics, allow them to
be fetched, enabled, and disabled via sysfs.

Enable and disable via the boolean:

/sys/devices/systems/cpu/cpuN/mmustat_enable

Statistic values are provided under:

/sys/devices/systems/cpu/cpuN/mmu_status/

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/asm-sparc64/hypervisor.h b/include/asm-sparc64/hypervisor.h
index 4a43075..5c2f9d4 100644
--- a/include/asm-sparc64/hypervisor.h
+++ b/include/asm-sparc64/hypervisor.h
@@ -2798,6 +2798,11 @@
  */
 #define HV_FAST_MMUSTAT_INFO		0x103
 
+#ifndef __ASSEMBLY__
+extern unsigned long sun4v_mmustat_conf(unsigned long ra, unsigned long *orig_ra);
+extern unsigned long sun4v_mmustat_info(unsigned long *ra);
+#endif
+
 /* NCS crypto services  */
 
 /* ncs_request() sub-function numbers */