[SPARC64]: Add sun4v_cpu_yield().

Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/kernel/entry.S

@@ -1786,3 +1786,12 @@ sun4v_cpu_qconf:
 	ta	HV_FAST_TRAP
 	retl
 	 nop
+
+	/* returns %o0:	status
+	 */
+	.globl	sun4v_cpu_yield
+sun4v_cpu_yield:
+	mov	HV_FAST_CPU_YIELD, %o5
+	ta	HV_FAST_TRAP
+	retl
+	 nop

include/asm-sparc64/hypervisor.h

@@ -258,6 +258,9 @@
  */
 #define HV_FAST_CPU_YIELD		0x12
 
+#ifndef __ASSEMBLY__
+extern unsigned long sun4v_cpu_yield(void);
+#endif
 
 /* cpu_qconf()
  * TRAP:	HV_FAST_TRAP