Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  clocksource, acpi_pm.c: check for monotonicity
  clocksource, acpi_pm.c: use proper read function also in errata mode
  ntp: fix calculation of the next jiffie to trigger RTC sync
  x86: HPET: read back compare register before reading counter
  x86: HPET fix moronic 32/64bit thinko
  clockevents: broadcast fixup possible waiters
  HPET: make minimum reprogramming delta useful
  clockevents: prevent endless loop lockup
  clockevents: prevent multiple init/shutdown
  clockevents: enforce reprogram in oneshot setup
  clockevents: prevent endless loop in periodic broadcast handler
  clockevents: prevent clockevent event_handler ending up handler_noop

6 files changed, 103 insertions, 29 deletions

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 3d1e3e1a197..1876b526c77 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -177,7 +177,7 @@ void clockevents_register_device(struct clock_event_device *dev)
 /*
  * Noop handler when we shut down an event device
  */
-static void clockevents_handle_noop(struct clock_event_device *dev)
+void clockevents_handle_noop(struct clock_event_device *dev)
 {
 }
 
@@ -199,7 +199,6 @@ void clockevents_exchange_device(struct clock_event_device *old,
 	 * released list and do a notify add later.
 	 */
 	if (old) {
-		old->event_handler = clockevents_handle_noop;
 		clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
 		list_del(&old->list);
 		list_add(&old->list, &clockevents_released);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 5125ddd8196..1ad46f3df6e 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -245,7 +245,7 @@ static void sync_cmos_clock(unsigned long dummy)
 	if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
 		fail = update_persistent_clock(now);
 
-	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
+	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
 	if (next.tv_nsec <= 0)
 		next.tv_nsec += NSEC_PER_SEC;
 
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 31463d370b9..2f5a38294bf 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -175,6 +175,8 @@ static void tick_do_periodic_broadcast(void)
  */
 static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 {
+	ktime_t next;
+
 	tick_do_periodic_broadcast();
 
 	/*
@@ -185,10 +187,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 
 	/*
 	 * Setup the next period for devices, which do not have
-	 * periodic mode:
+	 * periodic mode. We read dev->next_event first and add to it
+	 * when the event alrady expired. clockevents_program_event()
+	 * sets dev->next_event only when the event is really
+	 * programmed to the device.
 	 */
-	for (;;) {
-		ktime_t next = ktime_add(dev->next_event, tick_period);
+	for (next = dev->next_event; ;) {
+		next = ktime_add(next, tick_period);
 
 		if (!clockevents_program_event(dev, next, ktime_get()))
 			return;
@@ -205,7 +210,7 @@ static void tick_do_broadcast_on_off(void *why)
 	struct clock_event_device *bc, *dev;
 	struct tick_device *td;
 	unsigned long flags, *reason = why;
-	int cpu;
+	int cpu, bc_stopped;
 
 	spin_lock_irqsave(&tick_broadcast_lock, flags);
 
@@ -223,6 +228,8 @@ static void tick_do_broadcast_on_off(void *why)
 	if (!tick_device_is_functional(dev))
 		goto out;
 
+	bc_stopped = cpus_empty(tick_broadcast_mask);
+
 	switch (*reason) {
 	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
 	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
@@ -245,9 +252,10 @@ static void tick_do_broadcast_on_off(void *why)
 		break;
 	}
 
-	if (cpus_empty(tick_broadcast_mask))
-		clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
-	else {
+	if (cpus_empty(tick_broadcast_mask)) {
+		if (!bc_stopped)
+			clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+	} else if (bc_stopped) {
 		if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
 			tick_broadcast_start_periodic(bc);
 		else
@@ -364,16 +372,8 @@ cpumask_t *tick_get_broadcast_oneshot_mask(void)
 static int tick_broadcast_set_event(ktime_t expires, int force)
 {
 	struct clock_event_device *bc = tick_broadcast_device.evtdev;
-	ktime_t now = ktime_get();
-	int res;
-
-	for(;;) {
-		res = clockevents_program_event(bc, expires, now);
-		if (!res || !force)
-			return res;
-		now = ktime_get();
-		expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
-	}
+
+	return tick_dev_program_event(bc, expires, force);
 }
 
 int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
@@ -491,14 +491,52 @@ static void tick_broadcast_clear_oneshot(int cpu)
 	cpu_clear(cpu, tick_broadcast_oneshot_mask);
 }
 
+static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires)
+{
+	struct tick_device *td;
+	int cpu;
+
+	for_each_cpu_mask_nr(cpu, *mask) {
+		td = &per_cpu(tick_cpu_device, cpu);
+		if (td->evtdev)
+			td->evtdev->next_event = expires;
+	}
+}
+
 /**
  * tick_broadcast_setup_oneshot - setup the broadcast device
  */
 void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
-	bc->event_handler = tick_handle_oneshot_broadcast;
-	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
-	bc->next_event.tv64 = KTIME_MAX;
+	/* Set it up only once ! */
+	if (bc->event_handler != tick_handle_oneshot_broadcast) {
+		int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
+		int cpu = smp_processor_id();
+		cpumask_t mask;
+
+		bc->event_handler = tick_handle_oneshot_broadcast;
+		clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+
+		/* Take the do_timer update */
+		tick_do_timer_cpu = cpu;
+
+		/*
+		 * We must be careful here. There might be other CPUs
+		 * waiting for periodic broadcast. We need to set the
+		 * oneshot_mask bits for those and program the
+		 * broadcast device to fire.
+		 */
+		mask = tick_broadcast_mask;
+		cpu_clear(cpu, mask);
+		cpus_or(tick_broadcast_oneshot_mask,
+			tick_broadcast_oneshot_mask, mask);
+
+		if (was_periodic && !cpus_empty(mask)) {
+			tick_broadcast_init_next_event(&mask, tick_next_period);
+			tick_broadcast_set_event(tick_next_period, 1);
+		} else
+			bc->next_event.tv64 = KTIME_MAX;
+	}
 }
 
 /*
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 80c4336f418..c4777193d56 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -161,6 +161,7 @@ static void tick_setup_device(struct tick_device *td,
 	} else {
 		handler = td->evtdev->event_handler;
 		next_event = td->evtdev->next_event;
+		td->evtdev->event_handler = clockevents_handle_noop;
 	}
 
 	td->evtdev = newdev;
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f13f2b7f4fd..0ffc2918ea6 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -17,6 +17,8 @@ extern void tick_handle_periodic(struct clock_event_device *dev);
 extern void tick_setup_oneshot(struct clock_event_device *newdev,
 			       void (*handler)(struct clock_event_device *),
 			       ktime_t nextevt);
+extern int tick_dev_program_event(struct clock_event_device *dev,
+				  ktime_t expires, int force);
 extern int tick_program_event(ktime_t expires, int force);
 extern void tick_oneshot_notify(void);
 extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 450c04935b6..2e35501e61d 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -23,24 +23,58 @@
 #include "tick-internal.h"
 
 /**
- * tick_program_event
+ * tick_program_event internal worker function
  */
-int tick_program_event(ktime_t expires, int force)
+int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
+			   int force)
 {
-	struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
 	ktime_t now = ktime_get();
+	int i;
 
-	while (1) {
+	for (i = 0;;) {
 		int ret = clockevents_program_event(dev, expires, now);
 
 		if (!ret || !force)
 			return ret;
+
+		/*
+		 * We tried 2 times to program the device with the given
+		 * min_delta_ns. If that's not working then we double it
+		 * and emit a warning.
+		 */
+		if (++i > 2) {
+			printk(KERN_WARNING "CE: __tick_program_event of %s is "
+			       "stuck %llx %llx\n", dev->name ? dev->name : "?",
+			       now.tv64, expires.tv64);
+			printk(KERN_WARNING
+			       "CE: increasing min_delta_ns %ld to %ld nsec\n",
+			       dev->min_delta_ns, dev->min_delta_ns << 1);
+			WARN_ON(1);
+
+			/* Double the min. delta and try again */
+			if (!dev->min_delta_ns)
+				dev->min_delta_ns = 5000;
+			else
+				dev->min_delta_ns <<= 1;
+			i = 0;
+		}
+
 		now = ktime_get();
-		expires = ktime_add(now, ktime_set(0, dev->min_delta_ns));
+		expires = ktime_add_ns(now, dev->min_delta_ns);
 	}
 }
 
 /**
+ * tick_program_event
+ */
+int tick_program_event(ktime_t expires, int force)
+{
+	struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
+
+	return tick_dev_program_event(dev, expires, force);
+}
+
+/**
  * tick_resume_onshot - resume oneshot mode
  */
 void tick_resume_oneshot(void)
@@ -61,7 +95,7 @@ void tick_setup_oneshot(struct clock_event_device *newdev,
 {
 	newdev->event_handler = handler;
 	clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT);
-	clockevents_program_event(newdev, next_event, ktime_get());
+	tick_dev_program_event(newdev, next_event, 1);
 }
 
 /**