3 files changed, 32 insertions, 11 deletions

diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index ac151399ef34..1995c1712fc8 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -95,7 +95,6 @@ EXPORT_SYMBOL_GPL(s390_handle_mcck);
 static int notrace s390_revalidate_registers(struct mci *mci)
 {
 	int kill_task;
-	u64 tmpclock;
 	u64 zero;
 	void *fpt_save_area, *fpt_creg_save_area;
 
@@ -214,11 +213,10 @@ static int notrace s390_revalidate_registers(struct mci *mci)
 			: "0", "cc");
 #endif
 	/* Revalidate clock comparator register */
-	asm volatile(
-		"	stck	0(%1)\n"
-		"	sckc	0(%1)"
-		: "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
-
+	if (S390_lowcore.clock_comparator == -1)
+		set_clock_comparator(S390_lowcore.mcck_clock);
+	else
+		set_clock_comparator(S390_lowcore.clock_comparator);
 	/* Check if old PSW is valid */
 	if (!mci->wp)
 		/*
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 56c8687b29b3..7eff9b7347c0 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -19,6 +19,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/rcupdate.h>
 #include <linux/posix-timers.h>
+#include <linux/cpu.h>
 
 #include <asm/s390_ext.h>
 #include <asm/timer.h>
@@ -566,6 +567,23 @@ void init_cpu_vtimer(void)
 	__ctl_set_bit(0,10);
 }
 
+static int __cpuinit s390_nohz_notify(struct notifier_block *self,
+				      unsigned long action, void *hcpu)
+{
+	struct s390_idle_data *idle;
+	long cpu = (long) hcpu;
+
+	idle = &per_cpu(s390_idle, cpu);
+	switch (action) {
+	case CPU_DYING:
+	case CPU_DYING_FROZEN:
+		idle->nohz_delay = 0;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
 void __init vtime_init(void)
 {
 	/* request the cpu timer external interrupt */
@@ -574,5 +592,6 @@ void __init vtime_init(void)
 
 	/* Enable cpu timer interrupts on the boot cpu. */
 	init_cpu_vtimer();
+	cpu_notifier(s390_nohz_notify, 0);
 }
 
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 752b362bf651..7c37ec359ec2 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -29,17 +29,21 @@ static void __udelay_disabled(unsigned long long usecs)
 {
 	unsigned long mask, cr0, cr0_saved;
 	u64 clock_saved;
+	u64 end;
 
+	mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
+	end = get_clock() + (usecs << 12);
 	clock_saved = local_tick_disable();
-	set_clock_comparator(get_clock() + (usecs << 12));
 	__ctl_store(cr0_saved, 0, 0);
 	cr0 = (cr0_saved & 0xffff00e0) | 0x00000800;
 	__ctl_load(cr0 , 0, 0);
-	mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
 	lockdep_off();
-	trace_hardirqs_on();
-	__load_psw_mask(mask);
-	local_irq_disable();
+	do {
+		set_clock_comparator(end);
+		trace_hardirqs_on();
+		__load_psw_mask(mask);
+		local_irq_disable();
+	} while (get_clock() < end);
 	lockdep_on();
 	__ctl_load(cr0_saved, 0, 0);
 	local_tick_enable(clock_saved);