diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 585a6e3..429834e 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -317,7 +317,7 @@
 	BUG_ON(rc);
 
 	while(per_cpu(cpu_state, cpu) != CPU_ONLINE) {
-		HYPERVISOR_sched_op(SCHEDOP_yield, 0);
+		HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
 		barrier();
 	}
 
@@ -422,7 +422,7 @@
 	/* Make sure other vcpus get a chance to run if they need to. */
 	for_each_cpu(cpu, mask) {
 		if (xen_vcpu_stolen(cpu)) {
-			HYPERVISOR_sched_op(SCHEDOP_yield, 0);
+			HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
 			break;
 		}
 	}