MIPS: CMP: Fix memory barriers for correct operation of amon_cpu_start

Signed-off-by: Chris Dearman (chris@mips.com)
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/mti-malta/malta-amon.c

@@ -70,11 +70,12 @@ void amon_cpu_start(int cpu,
 	launch->sp = sp;
 	launch->a0 = a0;
 
-	/* Make sure target sees parameters before the go bit */
-	smp_mb();
-
+	smp_wmb();              /* Target must see parameters before go */
 	launch->flags |= LAUNCH_FGO;
+	smp_wmb();              /* Target must see go before we poll  */
+
 	while ((launch->flags & LAUNCH_FGONE) == 0)
 		;
+	smp_rmb();      /* Target will be updating flags soon */
 	pr_debug("launch: cpu%d gone!\n", cpu);
 }