xen: re-register runstate area earlier on resume.

This is necessary to ensure the runstate area is available to
xen_sched_clock before any calls to printk which will require it in
order to provide a timestamp.

I chose to pull the xen_setup_runstate_info out of xen_time_init into
the caller in order to maintain parity with calling
xen_setup_runstate_info separately from calling xen_time_resume.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 0a5aa44..6bbff94 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -100,7 +100,7 @@
 	return per_cpu(runstate, vcpu).state == RUNSTATE_runnable;
 }
 
-static void setup_runstate_info(int cpu)
+void xen_setup_runstate_info(int cpu)
 {
 	struct vcpu_register_runstate_memory_area area;
 
@@ -442,8 +442,6 @@
 
 	evt->cpumask = cpumask_of(cpu);
 	evt->irq = irq;
-
-	setup_runstate_info(cpu);
 }
 
 void xen_teardown_timer(int cpu)
@@ -494,6 +492,7 @@
 
 	setup_force_cpu_cap(X86_FEATURE_TSC);
 
+	xen_setup_runstate_info(cpu);
 	xen_setup_timer(cpu);
 	xen_setup_cpu_clockevents();
 }