13 files changed, 1062 insertions, 300 deletions

diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index ff7d9d2ab504..9250130646f5 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -4,6 +4,8 @@ obj-y += timeconv.o posix-clock.o alarmtimer.o
 obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD)         += clockevents.o
 obj-$(CONFIG_GENERIC_CLOCKEVENTS)               += tick-common.o
 obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)     += tick-broadcast.o
+obj-$(CONFIG_GENERIC_SCHED_CLOCK)               += sched_clock.o
 obj-$(CONFIG_TICK_ONESHOT)                      += tick-oneshot.o
 obj-$(CONFIG_TICK_ONESHOT)                      += tick-sched.o
 obj-$(CONFIG_TIMER_STATS)                       += timer_stats.o
+obj-$(CONFIG_DEBUG_FS)                          += timekeeping_debug.o
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index f11d83b12949..eec50fcef9e4 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -199,6 +199,13 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 
 }
 
+ktime_t alarm_expires_remaining(const struct alarm *alarm)
+{
+        struct alarm_base *base = &alarm_bases[alarm->type];
+        return ktime_sub(alarm->node.expires, base->gettime());
+}
+EXPORT_SYMBOL_GPL(alarm_expires_remaining);
+
 #ifdef CONFIG_RTC_CLASS
 /**
  * alarmtimer_suspend - Suspend time callback
@@ -303,9 +310,10 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
         alarm->type = type;
         alarm->state = ALARMTIMER_STATE_INACTIVE;
 }
+EXPORT_SYMBOL_GPL(alarm_init);
 
 /**
- * alarm_start - Sets an alarm to fire
+ * alarm_start - Sets an absolute alarm to fire
  * @alarm: ptr to alarm to set
  * @start: time to run the alarm
  */
@@ -323,6 +331,34 @@ int alarm_start(struct alarm *alarm, ktime_t start)
         spin_unlock_irqrestore(&base->lock, flags);
         return ret;
 }
+EXPORT_SYMBOL_GPL(alarm_start);
+
+/**
+ * alarm_start_relative - Sets a relative alarm to fire
+ * @alarm: ptr to alarm to set
+ * @start: time relative to now to run the alarm
+ */
+int alarm_start_relative(struct alarm *alarm, ktime_t start)
+{
+        struct alarm_base *base = &alarm_bases[alarm->type];
+
+        start = ktime_add(start, base->gettime());
+        return alarm_start(alarm, start);
+}
+EXPORT_SYMBOL_GPL(alarm_start_relative);
+
+void alarm_restart(struct alarm *alarm)
+{
+        struct alarm_base *base = &alarm_bases[alarm->type];
+        unsigned long flags;
+
+        spin_lock_irqsave(&base->lock, flags);
+        hrtimer_set_expires(&alarm->timer, alarm->node.expires);
+        hrtimer_restart(&alarm->timer);
+        alarmtimer_enqueue(base, alarm);
+        spin_unlock_irqrestore(&base->lock, flags);
+}
+EXPORT_SYMBOL_GPL(alarm_restart);
 
 /**
  * alarm_try_to_cancel - Tries to cancel an alarm timer
@@ -344,6 +380,7 @@ int alarm_try_to_cancel(struct alarm *alarm)
         spin_unlock_irqrestore(&base->lock, flags);
         return ret;
 }
+EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
 
 
 /**
@@ -361,6 +398,7 @@ int alarm_cancel(struct alarm *alarm)
                 cpu_relax();
         }
 }
+EXPORT_SYMBOL_GPL(alarm_cancel);
 
 
 u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
@@ -393,8 +431,15 @@ u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
         alarm->node.expires = ktime_add(alarm->node.expires, interval);
         return overrun;
 }
+EXPORT_SYMBOL_GPL(alarm_forward);
 
+u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
+{
+        struct alarm_base *base = &alarm_bases[alarm->type];
 
+        return alarm_forward(alarm, base->gettime(), interval);
+}
+EXPORT_SYMBOL_GPL(alarm_forward_now);
 
 
 /**
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index c6d6400ee137..38959c866789 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -15,20 +15,23 @@
 #include <linux/hrtimer.h>
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/notifier.h>
 #include <linux/smp.h>
+#include <linux/device.h>
 
 #include "tick-internal.h"
 
 /* The registered clock event devices */
 static LIST_HEAD(clockevent_devices);
 static LIST_HEAD(clockevents_released);
-
-/* Notification for clock events */
-static RAW_NOTIFIER_HEAD(clockevents_chain);
-
 /* Protection for the above */
 static DEFINE_RAW_SPINLOCK(clockevents_lock);
+/* Protection for unbind operations */
+static DEFINE_MUTEX(clockevents_mutex);
+
+struct ce_unbind {
+        struct clock_event_device *ce;
+        int res;
+};
 
 /**
  * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
@@ -232,47 +235,107 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
         return (rc && force) ? clockevents_program_min_delta(dev) : rc;
 }
 
-/**
- * clockevents_register_notifier - register a clock events change listener
+/*
+ * Called after a notify add to make devices available which were
+ * released from the notifier call.
  */
-int clockevents_register_notifier(struct notifier_block *nb)
+static void clockevents_notify_released(void)
 {
-        unsigned long flags;
-        int ret;
+        struct clock_event_device *dev;
 
-        raw_spin_lock_irqsave(&clockevents_lock, flags);
-        ret = raw_notifier_chain_register(&clockevents_chain, nb);
-        raw_spin_unlock_irqrestore(&clockevents_lock, flags);
+        while (!list_empty(&clockevents_released)) {
+                dev = list_entry(clockevents_released.next,
+                                 struct clock_event_device, list);
+                list_del(&dev->list);
+                list_add(&dev->list, &clockevent_devices);
+                tick_check_new_device(dev);
+        }
+}
 
-        return ret;
+/*
+ * Try to install a replacement clock event device
+ */
+static int clockevents_replace(struct clock_event_device *ced)
+{
+        struct clock_event_device *dev, *newdev = NULL;
+
+        list_for_each_entry(dev, &clockevent_devices, list) {
+                if (dev == ced || dev->mode != CLOCK_EVT_MODE_UNUSED)
+                        continue;
+
+                if (!tick_check_replacement(newdev, dev))
+                        continue;
+
+                if (!try_module_get(dev->owner))
+                        continue;
+
+                if (newdev)
+                        module_put(newdev->owner);
+                newdev = dev;
+        }
+        if (newdev) {
+                tick_install_replacement(newdev);
+                list_del_init(&ced->list);
+        }
+        return newdev ? 0 : -EBUSY;
 }
 
 /*
- * Notify about a clock event change. Called with clockevents_lock
- * held.
+ * Called with clockevents_mutex and clockevents_lock held
  */
-static void clockevents_do_notify(unsigned long reason, void *dev)
+static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu)
 {
-        raw_notifier_call_chain(&clockevents_chain, reason, dev);
+        /* Fast track. Device is unused */
+        if (ced->mode == CLOCK_EVT_MODE_UNUSED) {
+                list_del_init(&ced->list);
+                return 0;
+        }
+
+        return ced == per_cpu(tick_cpu_device, cpu).evtdev ? -EAGAIN : -EBUSY;
 }
 
 /*
- * Called after a notify add to make devices available which were
- * released from the notifier call.
+ * SMP function call to unbind a device
  */
-static void clockevents_notify_released(void)
+static void __clockevents_unbind(void *arg)
 {
-        struct clock_event_device *dev;
+        struct ce_unbind *cu = arg;
+        int res;
+
+        raw_spin_lock(&clockevents_lock);
+        res = __clockevents_try_unbind(cu->ce, smp_processor_id());
+        if (res == -EAGAIN)
+                res = clockevents_replace(cu->ce);
+        cu->res = res;
+        raw_spin_unlock(&clockevents_lock);
+}
 
-        while (!list_empty(&clockevents_released)) {
-                dev = list_entry(clockevents_released.next,
-                                 struct clock_event_device, list);
-                list_del(&dev->list);
-                list_add(&dev->list, &clockevent_devices);
-                clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
-        }
+/*
+ * Issues smp function call to unbind a per cpu device. Called with
+ * clockevents_mutex held.
+ */
+static int clockevents_unbind(struct clock_event_device *ced, int cpu)
+{
+        struct ce_unbind cu = { .ce = ced, .res = -ENODEV };
+
+        smp_call_function_single(cpu, __clockevents_unbind, &cu, 1);
+        return cu.res;
 }
 
+/*
+ * Unbind a clockevents device.
+ */
+int clockevents_unbind_device(struct clock_event_device *ced, int cpu)
+{
+        int ret;
+
+        mutex_lock(&clockevents_mutex);
+        ret = clockevents_unbind(ced, cpu);
+        mutex_unlock(&clockevents_mutex);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(clockevents_unbind);
+
 /**
  * clockevents_register_device - register a clock event device
  * @dev:        device to register
@@ -290,7 +353,7 @@ void clockevents_register_device(struct clock_event_device *dev)
         raw_spin_lock_irqsave(&clockevents_lock, flags);
 
         list_add(&dev->list, &clockevent_devices);
-        clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
+        tick_check_new_device(dev);
         clockevents_notify_released();
 
         raw_spin_unlock_irqrestore(&clockevents_lock, flags);
@@ -386,6 +449,7 @@ void clockevents_exchange_device(struct clock_event_device *old,
          * released list and do a notify add later.
          */
         if (old) {
+                module_put(old->owner);
                 clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
                 list_del(&old->list);
                 list_add(&old->list, &clockevents_released);
@@ -433,10 +497,36 @@ void clockevents_notify(unsigned long reason, void *arg)
         int cpu;
 
         raw_spin_lock_irqsave(&clockevents_lock, flags);
-        clockevents_do_notify(reason, arg);
 
         switch (reason) {
+        case CLOCK_EVT_NOTIFY_BROADCAST_ON:
+        case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
+        case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
+                tick_broadcast_on_off(reason, arg);
+                break;
+
+        case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:
+        case CLOCK_EVT_NOTIFY_BROADCAST_EXIT:
+                tick_broadcast_oneshot_control(reason);
+                break;
+
+        case CLOCK_EVT_NOTIFY_CPU_DYING:
+                tick_handover_do_timer(arg);
+                break;
+
+        case CLOCK_EVT_NOTIFY_SUSPEND:
+                tick_suspend();
+                tick_suspend_broadcast();
+                break;
+
+        case CLOCK_EVT_NOTIFY_RESUME:
+                tick_resume();
+                break;
+
         case CLOCK_EVT_NOTIFY_CPU_DEAD:
+                tick_shutdown_broadcast_oneshot(arg);
+                tick_shutdown_broadcast(arg);
+                tick_shutdown(arg);
                 /*
                  * Unregister the clock event devices which were
                  * released from the users in the notify chain.
@@ -462,4 +552,123 @@ void clockevents_notify(unsigned long reason, void *arg)
         raw_spin_unlock_irqrestore(&clockevents_lock, flags);
 }
 EXPORT_SYMBOL_GPL(clockevents_notify);
+
+#ifdef CONFIG_SYSFS
+struct bus_type clockevents_subsys = {
+        .name           = "clockevents",
+        .dev_name       = "clockevent",
+};
+
+static DEFINE_PER_CPU(struct device, tick_percpu_dev);
+static struct tick_device *tick_get_tick_dev(struct device *dev);
+
+static ssize_t sysfs_show_current_tick_dev(struct device *dev,
+                                           struct device_attribute *attr,
+                                           char *buf)
+{
+        struct tick_device *td;
+        ssize_t count = 0;
+
+        raw_spin_lock_irq(&clockevents_lock);
+        td = tick_get_tick_dev(dev);
+        if (td && td->evtdev)
+                count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name);
+        raw_spin_unlock_irq(&clockevents_lock);
+        return count;
+}
+static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL);
+
+/* We don't support the abomination of removable broadcast devices */
+static ssize_t sysfs_unbind_tick_dev(struct device *dev,
+                                     struct device_attribute *attr,
+                                     const char *buf, size_t count)
+{
+        char name[CS_NAME_LEN];
+        size_t ret = sysfs_get_uname(buf, name, count);
+        struct clock_event_device *ce;
+
+        if (ret < 0)
+                return ret;
+
+        ret = -ENODEV;
+        mutex_lock(&clockevents_mutex);
+        raw_spin_lock_irq(&clockevents_lock);
+        list_for_each_entry(ce, &clockevent_devices, list) {
+                if (!strcmp(ce->name, name)) {
+                        ret = __clockevents_try_unbind(ce, dev->id);
+                        break;
+                }
+        }
+        raw_spin_unlock_irq(&clockevents_lock);
+        /*
+         * We hold clockevents_mutex, so ce can't go away
+         */
+        if (ret == -EAGAIN)
+                ret = clockevents_unbind(ce, dev->id);
+        mutex_unlock(&clockevents_mutex);
+        return ret ? ret : count;
+}
+static DEVICE_ATTR(unbind_device, 0200, NULL, sysfs_unbind_tick_dev);
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+static struct device tick_bc_dev = {
+        .init_name      = "broadcast",
+        .id             = 0,
+        .bus            = &clockevents_subsys,
+};
+
+static struct tick_device *tick_get_tick_dev(struct device *dev)
+{
+        return dev == &tick_bc_dev ? tick_get_broadcast_device() :
+                &per_cpu(tick_cpu_device, dev->id);
+}
+
+static __init int tick_broadcast_init_sysfs(void)
+{
+        int err = device_register(&tick_bc_dev);
+
+        if (!err)
+                err = device_create_file(&tick_bc_dev, &dev_attr_current_device);
+        return err;
+}
+#else
+static struct tick_device *tick_get_tick_dev(struct device *dev)
+{
+        return &per_cpu(tick_cpu_device, dev->id);
+}
+static inline int tick_broadcast_init_sysfs(void) { return 0; }
 #endif
+
+static int __init tick_init_sysfs(void)
+{
+        int cpu;
+
+        for_each_possible_cpu(cpu) {
+                struct device *dev = &per_cpu(tick_percpu_dev, cpu);
+                int err;
+
+                dev->id = cpu;
+                dev->bus = &clockevents_subsys;
+                err = device_register(dev);
+                if (!err)
+                        err = device_create_file(dev, &dev_attr_current_device);
+                if (!err)
+                        err = device_create_file(dev, &dev_attr_unbind_device);
+                if (err)
+                        return err;
+        }
+        return tick_broadcast_init_sysfs();
+}
+
+static int __init clockevents_init_sysfs(void)
+{
+        int err = subsys_system_register(&clockevents_subsys, NULL);
+
+        if (!err)
+                err = tick_init_sysfs();
+        return err;
+}
+device_initcall(clockevents_init_sysfs);
+#endif /* SYSFS */
+
+#endif /* GENERIC_CLOCK_EVENTS */
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c9583382141a..50a8736757f3 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -31,6 +31,8 @@
 #include <linux/tick.h>
 #include <linux/kthread.h>
 
+#include "tick-internal.h"
+
 void timecounter_init(struct timecounter *tc,
                       const struct cyclecounter *cc,
                       u64 start_tstamp)
@@ -174,11 +176,12 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 maxsec)
 static struct clocksource *curr_clocksource;
 static LIST_HEAD(clocksource_list);
 static DEFINE_MUTEX(clocksource_mutex);
-static char override_name[32];
+static char override_name[CS_NAME_LEN];
 static int finished_booting;
 
 #ifdef CONFIG_CLOCKSOURCE_WATCHDOG
 static void clocksource_watchdog_work(struct work_struct *work);
+static void clocksource_select(void);
 
 static LIST_HEAD(watchdog_list);
 static struct clocksource *watchdog;
@@ -299,13 +302,30 @@ static void clocksource_watchdog(unsigned long data)
                 if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) &&
                     (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
                     (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {
+                        /* Mark it valid for high-res. */
                         cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+
+                        /*
+                         * clocksource_done_booting() will sort it if
+                         * finished_booting is not set yet.
+                         */
+                        if (!finished_booting)
+                                continue;
+
                         /*
-                         * We just marked the clocksource as highres-capable,
-                         * notify the rest of the system as well so that we
-                         * transition into high-res mode:
+                         * If this is not the current clocksource let
+                         * the watchdog thread reselect it. Due to the
+                         * change to high res this clocksource might
+                         * be preferred now. If it is the current
+                         * clocksource let the tick code know about
+                         * that change.
                          */
-                        tick_clock_notify();
+                        if (cs != curr_clocksource) {
+                                cs->flags |= CLOCK_SOURCE_RESELECT;
+                                schedule_work(&watchdog_work);
+                        } else {
+                                tick_clock_notify();
+                        }
                 }
         }
 
@@ -388,44 +408,39 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs)
 
 static void clocksource_dequeue_watchdog(struct clocksource *cs)
 {
-        struct clocksource *tmp;
         unsigned long flags;
 
         spin_lock_irqsave(&watchdog_lock, flags);
-        if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
-                /* cs is a watched clocksource. */
-                list_del_init(&cs->wd_list);
-        } else if (cs == watchdog) {
-                /* Reset watchdog cycles */
-                clocksource_reset_watchdog();
-                /* Current watchdog is removed. Find an alternative. */
-                watchdog = NULL;
-                list_for_each_entry(tmp, &clocksource_list, list) {
-                        if (tmp == cs || tmp->flags & CLOCK_SOURCE_MUST_VERIFY)
-                                continue;
-                        if (!watchdog || tmp->rating > watchdog->rating)
-                                watchdog = tmp;
+        if (cs != watchdog) {
+                if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
+                        /* cs is a watched clocksource. */
+                        list_del_init(&cs->wd_list);
+                        /* Check if the watchdog timer needs to be stopped. */
+                        clocksource_stop_watchdog();
                 }
         }
-        cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
-        /* Check if the watchdog timer needs to be stopped. */
-        clocksource_stop_watchdog();
         spin_unlock_irqrestore(&watchdog_lock, flags);
 }
 
-static int clocksource_watchdog_kthread(void *data)
+static int __clocksource_watchdog_kthread(void)
 {
         struct clocksource *cs, *tmp;
         unsigned long flags;
         LIST_HEAD(unstable);
+        int select = 0;
 
-        mutex_lock(&clocksource_mutex);
         spin_lock_irqsave(&watchdog_lock, flags);
-        list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list)
+        list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) {
                 if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
                         list_del_init(&cs->wd_list);
                         list_add(&cs->wd_list, &unstable);
+                        select = 1;
                 }
+                if (cs->flags & CLOCK_SOURCE_RESELECT) {
+                        cs->flags &= ~CLOCK_SOURCE_RESELECT;
+                        select = 1;
+                }
+        }
         /* Check if the watchdog timer needs to be stopped. */
         clocksource_stop_watchdog();
         spin_unlock_irqrestore(&watchdog_lock, flags);
@@ -435,10 +450,23 @@ static int clocksource_watchdog_kthread(void *data)
                 list_del_init(&cs->wd_list);
                 __clocksource_change_rating(cs, 0);
         }
+        return select;
+}
+
+static int clocksource_watchdog_kthread(void *data)
+{
+        mutex_lock(&clocksource_mutex);
+        if (__clocksource_watchdog_kthread())
+                clocksource_select();
         mutex_unlock(&clocksource_mutex);
         return 0;
 }
 
+static bool clocksource_is_watchdog(struct clocksource *cs)
+{
+        return cs == watchdog;
+}
+
 #else /* CONFIG_CLOCKSOURCE_WATCHDOG */
 
 static void clocksource_enqueue_watchdog(struct clocksource *cs)
@@ -449,7 +477,8 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs)
 
 static inline void clocksource_dequeue_watchdog(struct clocksource *cs) { }
 static inline void clocksource_resume_watchdog(void) { }
-static inline int clocksource_watchdog_kthread(void *data) { return 0; }
+static inline int __clocksource_watchdog_kthread(void) { return 0; }
+static bool clocksource_is_watchdog(struct clocksource *cs) { return false; }
 
 #endif /* CONFIG_CLOCKSOURCE_WATCHDOG */
 
@@ -553,24 +582,42 @@ static u64 clocksource_max_deferment(struct clocksource *cs)
 
 #ifndef CONFIG_ARCH_USES_GETTIMEOFFSET
 
-/**
- * clocksource_select - Select the best clocksource available
- *
- * Private function. Must hold clocksource_mutex when called.
- *
- * Select the clocksource with the best rating, or the clocksource,
- * which is selected by userspace override.
- */
-static void clocksource_select(void)
+static struct clocksource *clocksource_find_best(bool oneshot, bool skipcur)
 {
-        struct clocksource *best, *cs;
+        struct clocksource *cs;
 
         if (!finished_booting || list_empty(&clocksource_list))
+                return NULL;
+
+        /*
+         * We pick the clocksource with the highest rating. If oneshot
+         * mode is active, we pick the highres valid clocksource with
+         * the best rating.
+         */
+        list_for_each_entry(cs, &clocksource_list, list) {
+                if (skipcur && cs == curr_clocksource)
+                        continue;
+                if (oneshot && !(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES))
+                        continue;
+                return cs;
+        }
+        return NULL;
+}
+
+static void __clocksource_select(bool skipcur)
+{
+        bool oneshot = tick_oneshot_mode_active();
+        struct clocksource *best, *cs;
+
+        /* Find the best suitable clocksource */
+        best = clocksource_find_best(oneshot, skipcur);
+        if (!best)
                 return;
-        /* First clocksource on the list has the best rating. */
-        best = list_first_entry(&clocksource_list, struct clocksource, list);
+
         /* Check for the override clocksource. */
         list_for_each_entry(cs, &clocksource_list, list) {
+                if (skipcur && cs == curr_clocksource)
+                        continue;
                 if (strcmp(cs->name, override_name) != 0)
                         continue;
                 /*
@@ -578,8 +625,7 @@ static void clocksource_select(void)
                  * capable clocksource if the tick code is in oneshot
                  * mode (highres or nohz)
                  */
-                if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) &&
-                    tick_oneshot_mode_active()) {
+                if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && oneshot) {
                         /* Override clocksource cannot be used. */
                         printk(KERN_WARNING "Override clocksource %s is not "
                                "HRT compatible. Cannot switch while in "
@@ -590,16 +636,35 @@ static void clocksource_select(void)
                         best = cs;
                 break;
         }
-        if (curr_clocksource != best) {
-                printk(KERN_INFO "Switching to clocksource %s\n", best->name);
+
+        if (curr_clocksource != best && !timekeeping_notify(best)) {
+                pr_info("Switched to clocksource %s\n", best->name);
                 curr_clocksource = best;
-                timekeeping_notify(curr_clocksource);
         }
 }
 
+/**
+ * clocksource_select - Select the best clocksource available
+ *
+ * Private function. Must hold clocksource_mutex when called.
+ *
+ * Select the clocksource with the best rating, or the clocksource,
+ * which is selected by userspace override.
+ */
+static void clocksource_select(void)
+{
+        return __clocksource_select(false);
+}
+
+static void clocksource_select_fallback(void)
+{
+        return __clocksource_select(true);
+}
+
 #else /* !CONFIG_ARCH_USES_GETTIMEOFFSET */
 
 static inline void clocksource_select(void) { }
+static inline void clocksource_select_fallback(void) { }
 
 #endif
 
@@ -614,16 +679,11 @@ static int __init clocksource_done_booting(void)
 {
         mutex_lock(&clocksource_mutex);
         curr_clocksource = clocksource_default_clock();
-        mutex_unlock(&clocksource_mutex);
-
         finished_booting = 1;
-
         /*
          * Run the watchdog first to eliminate unstable clock sources
          */
-        clocksource_watchdog_kthread(NULL);
-
-        mutex_lock(&clocksource_mutex);
+        __clocksource_watchdog_kthread();
         clocksource_select();
         mutex_unlock(&clocksource_mutex);
         return 0;
@@ -756,7 +816,6 @@ static void __clocksource_change_rating(struct clocksource *cs, int rating)
         list_del(&cs->list);
         cs->rating = rating;
         clocksource_enqueue(cs);
-        clocksource_select();
 }
 
 /**
@@ -768,21 +827,47 @@ void clocksource_change_rating(struct clocksource *cs, int rating)
 {
         mutex_lock(&clocksource_mutex);
         __clocksource_change_rating(cs, rating);
+        clocksource_select();
         mutex_unlock(&clocksource_mutex);
 }
 EXPORT_SYMBOL(clocksource_change_rating);
 
+/*
+ * Unbind clocksource @cs. Called with clocksource_mutex held
+ */
+static int clocksource_unbind(struct clocksource *cs)
+{
+        /*
+         * I really can't convince myself to support this on hardware
+         * designed by lobotomized monkeys.
+         */
+        if (clocksource_is_watchdog(cs))
+                return -EBUSY;
+
+        if (cs == curr_clocksource) {
+                /* Select and try to install a replacement clock source */
+                clocksource_select_fallback();
+                if (curr_clocksource == cs)
+                        return -EBUSY;
+        }
+        clocksource_dequeue_watchdog(cs);
+        list_del_init(&cs->list);
+        return 0;
+}
+
 /**
  * clocksource_unregister - remove a registered clocksource
  * @cs: clocksource to be unregistered
  */
-void clocksource_unregister(struct clocksource *cs)
+int clocksource_unregister(struct clocksource *cs)
 {
+        int ret = 0;
+
         mutex_lock(&clocksource_mutex);
-        clocksource_dequeue_watchdog(cs);
-        list_del(&cs->list);
-        clocksource_select();
+        if (!list_empty(&cs->list))
+                ret = clocksource_unbind(cs);
         mutex_unlock(&clocksource_mutex);
+        return ret;
 }
 EXPORT_SYMBOL(clocksource_unregister);
 
@@ -808,6 +893,23 @@ sysfs_show_current_clocksources(struct device *dev,
         return count;
 }
 
+size_t sysfs_get_uname(const char *buf, char *dst, size_t cnt)
+{
+        size_t ret = cnt;
+
+        /* strings from sysfs write are not 0 terminated! */
+        if (!cnt || cnt >= CS_NAME_LEN)
+                return -EINVAL;
+
+        /* strip of \n: */
+        if (buf[cnt-1] == '\n')
+                cnt--;
+        if (cnt > 0)
+                memcpy(dst, buf, cnt);
+        dst[cnt] = 0;
+        return ret;
+}
+
 /**
  * sysfs_override_clocksource - interface for manually overriding clocksource
  * @dev:        unused
@@ -822,22 +924,13 @@ static ssize_t sysfs_override_clocksource(struct device *dev,
                                           struct device_attribute *attr,
                                           const char *buf, size_t count)
 {
-        size_t ret = count;
-
-        /* strings from sysfs write are not 0 terminated! */
-        if (count >= sizeof(override_name))
-                return -EINVAL;
-
-        /* strip of \n: */
-        if (buf[count-1] == '\n')
-                count--;
+        size_t ret;
 
         mutex_lock(&clocksource_mutex);
 
-        if (count > 0)
-                memcpy(override_name, buf, count);
-        override_name[count] = 0;
-        clocksource_select();
+        ret = sysfs_get_uname(buf, override_name, count);
+        if (ret >= 0)
+                clocksource_select();
 
         mutex_unlock(&clocksource_mutex);
 
@@ -845,6 +938,40 @@ static ssize_t sysfs_override_clocksource(struct device *dev,
 }
 
 /**
+ * sysfs_unbind_current_clocksource - interface for manually unbinding clocksource
+ * @dev:        unused
+ * @attr:       unused
+ * @buf:        unused
+ * @count:      length of buffer
+ *
+ * Takes input from sysfs interface for manually unbinding a clocksource.
+ */
+static ssize_t sysfs_unbind_clocksource(struct device *dev,
+                                        struct device_attribute *attr,
+                                        const char *buf, size_t count)
+{
+        struct clocksource *cs;
+        char name[CS_NAME_LEN];
+        size_t ret;
+
+        ret = sysfs_get_uname(buf, name, count);
+        if (ret < 0)
+                return ret;
+
+        ret = -ENODEV;
+        mutex_lock(&clocksource_mutex);
+        list_for_each_entry(cs, &clocksource_list, list) {
+                if (strcmp(cs->name, name))
+                        continue;
+                ret = clocksource_unbind(cs);
+                break;
+        }
+        mutex_unlock(&clocksource_mutex);
+
+        return ret ? ret : count;
+}
+
+/**
  * sysfs_show_available_clocksources - sysfs interface for listing clocksource
  * @dev:        unused
  * @attr:       unused
@@ -886,6 +1013,8 @@ sysfs_show_available_clocksources(struct device *dev,
 static DEVICE_ATTR(current_clocksource, 0644, sysfs_show_current_clocksources,
                    sysfs_override_clocksource);
 
+static DEVICE_ATTR(unbind_clocksource, 0200, NULL, sysfs_unbind_clocksource);
+
 static DEVICE_ATTR(available_clocksource, 0444,
                    sysfs_show_available_clocksources, NULL);
 
@@ -910,6 +1039,9 @@ static int __init init_clocksource_sysfs(void)
                                 &device_clocksource,
                                 &dev_attr_current_clocksource);
         if (!error)
+                error = device_create_file(&device_clocksource,
+                                           &dev_attr_unbind_clocksource);
+        if (!error)
                 error = device_create_file(
                                 &device_clocksource,
                                 &dev_attr_available_clocksource);
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
new file mode 100644
index 000000000000..0b479a6a22bb
--- /dev/null
+++ b/kernel/time/sched_clock.c
@@ -0,0 +1,212 @@
+/*
+ * sched_clock.c: support for extending counters to full 64-bit ns counter
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/clocksource.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+#include <linux/syscore_ops.h>
+#include <linux/timer.h>
+#include <linux/sched_clock.h>
+
+struct clock_data {
+        u64 epoch_ns;
+        u32 epoch_cyc;
+        u32 epoch_cyc_copy;
+        unsigned long rate;
+        u32 mult;
+        u32 shift;
+        bool suspended;
+};
+
+static void sched_clock_poll(unsigned long wrap_ticks);
+static DEFINE_TIMER(sched_clock_timer, sched_clock_poll, 0, 0);
+static int irqtime = -1;
+
+core_param(irqtime, irqtime, int, 0400);
+
+static struct clock_data cd = {
+        .mult   = NSEC_PER_SEC / HZ,
+};
+
+static u32 __read_mostly sched_clock_mask = 0xffffffff;
+
+static u32 notrace jiffy_sched_clock_read(void)
+{
+        return (u32)(jiffies - INITIAL_JIFFIES);
+}
+
+static u32 __read_mostly (*read_sched_clock)(void) = jiffy_sched_clock_read;
+
+static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift)
+{
+        return (cyc * mult) >> shift;
+}
+
+static unsigned long long notrace sched_clock_32(void)
+{
+        u64 epoch_ns;
+        u32 epoch_cyc;
+        u32 cyc;
+
+        if (cd.suspended)
+                return cd.epoch_ns;
+
+        /*
+         * Load the epoch_cyc and epoch_ns atomically.  We do this by
+         * ensuring that we always write epoch_cyc, epoch_ns and
+         * epoch_cyc_copy in strict order, and read them in strict order.
+         * If epoch_cyc and epoch_cyc_copy are not equal, then we're in
+         * the middle of an update, and we should repeat the load.
+         */
+        do {
+                epoch_cyc = cd.epoch_cyc;
+                smp_rmb();
+                epoch_ns = cd.epoch_ns;
+                smp_rmb();
+        } while (epoch_cyc != cd.epoch_cyc_copy);
+
+        cyc = read_sched_clock();
+        cyc = (cyc - epoch_cyc) & sched_clock_mask;
+        return epoch_ns + cyc_to_ns(cyc, cd.mult, cd.shift);
+}
+
+/*
+ * Atomically update the sched_clock epoch.
+ */
+static void notrace update_sched_clock(void)
+{
+        unsigned long flags;
+        u32 cyc;
+        u64 ns;
+
+        cyc = read_sched_clock();
+        ns = cd.epoch_ns +
+                cyc_to_ns((cyc - cd.epoch_cyc) & sched_clock_mask,
+                          cd.mult, cd.shift);
+        /*
+         * Write epoch_cyc and epoch_ns in a way that the update is
+         * detectable in cyc_to_fixed_sched_clock().
+         */
+        raw_local_irq_save(flags);
+        cd.epoch_cyc_copy = cyc;
+        smp_wmb();
+        cd.epoch_ns = ns;
+        smp_wmb();
+        cd.epoch_cyc = cyc;
+        raw_local_irq_restore(flags);
+}
+
+static void sched_clock_poll(unsigned long wrap_ticks)
+{
+        mod_timer(&sched_clock_timer, round_jiffies(jiffies + wrap_ticks));
+        update_sched_clock();
+}
+
+void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)
+{
+        unsigned long r, w;
+        u64 res, wrap;
+        char r_unit;
+
+        if (cd.rate > rate)
+                return;
+
+        BUG_ON(bits > 32);
+        WARN_ON(!irqs_disabled());
+        read_sched_clock = read;
+        sched_clock_mask = (1ULL << bits) - 1;
+        cd.rate = rate;
+
+        /* calculate the mult/shift to convert counter ticks to ns. */
+        clocks_calc_mult_shift(&cd.mult, &cd.shift, rate, NSEC_PER_SEC, 0);
+
+        r = rate;
+        if (r >= 4000000) {
+                r /= 1000000;
+                r_unit = 'M';
+        } else if (r >= 1000) {
+                r /= 1000;
+                r_unit = 'k';
+        } else
+                r_unit = ' ';
+
+        /* calculate how many ns until we wrap */
+        wrap = cyc_to_ns((1ULL << bits) - 1, cd.mult, cd.shift);
+        do_div(wrap, NSEC_PER_MSEC);
+        w = wrap;
+
+        /* calculate the ns resolution of this counter */
+        res = cyc_to_ns(1ULL, cd.mult, cd.shift);
+        pr_info("sched_clock: %u bits at %lu%cHz, resolution %lluns, wraps every %lums\n",
+                bits, r, r_unit, res, w);
+
+        /*
+         * Start the timer to keep sched_clock() properly updated and
+         * sets the initial epoch.
+         */
+        sched_clock_timer.data = msecs_to_jiffies(w - (w / 10));
+        update_sched_clock();
+
+        /*
+         * Ensure that sched_clock() starts off at 0ns
+         */
+        cd.epoch_ns = 0;
+
+        /* Enable IRQ time accounting if we have a fast enough sched_clock */
+        if (irqtime > 0 || (irqtime == -1 && rate >= 1000000))
+                enable_sched_clock_irqtime();
+
+        pr_debug("Registered %pF as sched_clock source\n", read);
+}
+
+unsigned long long __read_mostly (*sched_clock_func)(void) = sched_clock_32;
+
+unsigned long long notrace sched_clock(void)
+{
+        return sched_clock_func();
+}
+
+void __init sched_clock_postinit(void)
+{
+        /*
+         * If no sched_clock function has been provided at that point,
+         * make it the final one one.
+         */
+        if (read_sched_clock == jiffy_sched_clock_read)
+                setup_sched_clock(jiffy_sched_clock_read, 32, HZ);
+
+        sched_clock_poll(sched_clock_timer.data);
+}
+
+static int sched_clock_suspend(void)
+{
+        sched_clock_poll(sched_clock_timer.data);
+        cd.suspended = true;
+        return 0;
+}
+
+static void sched_clock_resume(void)
+{
+        cd.epoch_cyc = read_sched_clock();
+        cd.epoch_cyc_copy = cd.epoch_cyc;
+        cd.suspended = false;
+}
+
+static struct syscore_ops sched_clock_ops = {
+        .suspend = sched_clock_suspend,
+        .resume = sched_clock_resume,
+};
+
+static int __init sched_clock_syscore_init(void)
+{
+        register_syscore_ops(&sched_clock_ops);
+        return 0;
+}
+device_initcall(sched_clock_syscore_init);
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 20d6fba70652..218bcb565fed 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -19,6 +19,7 @@
 #include <linux/profile.h>
 #include <linux/sched.h>
 #include <linux/smp.h>
+#include <linux/module.h>
 
 #include "tick-internal.h"
 
@@ -29,6 +30,7 @@
 
 static struct tick_device tick_broadcast_device;
 static cpumask_var_t tick_broadcast_mask;
+static cpumask_var_t tick_broadcast_on;
 static cpumask_var_t tmpmask;
 static DEFINE_RAW_SPINLOCK(tick_broadcast_lock);
 static int tick_broadcast_force;
@@ -64,17 +66,34 @@ static void tick_broadcast_start_periodic(struct clock_event_device *bc)
 /*
  * Check, if the device can be utilized as broadcast device:
  */
-int tick_check_broadcast_device(struct clock_event_device *dev)
+static bool tick_check_broadcast_device(struct clock_event_device *curdev,
+                                        struct clock_event_device *newdev)
+{
+        if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) ||
+            (newdev->features & CLOCK_EVT_FEAT_C3STOP))
+                return false;
+
+        if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT &&
+            !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
+                return false;
+
+        return !curdev || newdev->rating > curdev->rating;
+}
+
+/*
+ * Conditionally install/replace broadcast device
+ */
+void tick_install_broadcast_device(struct clock_event_device *dev)
 {
         struct clock_event_device *cur = tick_broadcast_device.evtdev;
 
-        if ((dev->features & CLOCK_EVT_FEAT_DUMMY) ||
-            (tick_broadcast_device.evtdev &&
-             tick_broadcast_device.evtdev->rating >= dev->rating) ||
-             (dev->features & CLOCK_EVT_FEAT_C3STOP))
-                return 0;
+        if (!tick_check_broadcast_device(cur, dev))
+                return;
+
+        if (!try_module_get(dev->owner))
+                return;
 
-        clockevents_exchange_device(tick_broadcast_device.evtdev, dev);
+        clockevents_exchange_device(cur, dev);
         if (cur)
                 cur->event_handler = clockevents_handle_noop;
         tick_broadcast_device.evtdev = dev;
@@ -90,7 +109,6 @@ int tick_check_broadcast_device(struct clock_event_device *dev)
          */
         if (dev->features & CLOCK_EVT_FEAT_ONESHOT)
                 tick_clock_notify();
-        return 1;
 }
 
 /*
@@ -123,8 +141,9 @@ static void tick_device_setup_broadcast_func(struct clock_event_device *dev)
  */
 int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
 {
+        struct clock_event_device *bc = tick_broadcast_device.evtdev;
         unsigned long flags;
-        int ret = 0;
+        int ret;
 
         raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
 
@@ -138,20 +157,62 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
                 dev->event_handler = tick_handle_periodic;
                 tick_device_setup_broadcast_func(dev);
                 cpumask_set_cpu(cpu, tick_broadcast_mask);
-                tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
+                if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+                        tick_broadcast_start_periodic(bc);
+                else
+                        tick_broadcast_setup_oneshot(bc);
                 ret = 1;
         } else {
                 /*
-                 * When the new device is not affected by the stop
-                 * feature and the cpu is marked in the broadcast mask
-                 * then clear the broadcast bit.
+                 * Clear the broadcast bit for this cpu if the
+                 * device is not power state affected.
                  */
-                if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
-                        int cpu = smp_processor_id();
+                if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
                         cpumask_clear_cpu(cpu, tick_broadcast_mask);
-                        tick_broadcast_clear_oneshot(cpu);
-                } else {
+                else
                         tick_device_setup_broadcast_func(dev);
+
+                /*
+                 * Clear the broadcast bit if the CPU is not in
+                 * periodic broadcast on state.
+                 */
+                if (!cpumask_test_cpu(cpu, tick_broadcast_on))
+                        cpumask_clear_cpu(cpu, tick_broadcast_mask);
+
+                switch (tick_broadcast_device.mode) {
+                case TICKDEV_MODE_ONESHOT:
+                        /*
+                         * If the system is in oneshot mode we can
+                         * unconditionally clear the oneshot mask bit,
+                         * because the CPU is running and therefore
+                         * not in an idle state which causes the power
+                         * state affected device to stop. Let the
+                         * caller initialize the device.
+                         */
+                        tick_broadcast_clear_oneshot(cpu);
+                        ret = 0;
+                        break;
+
+                case TICKDEV_MODE_PERIODIC:
+                        /*
+                         * If the system is in periodic mode, check
+                         * whether the broadcast device can be
+                         * switched off now.
+                         */
+                        if (cpumask_empty(tick_broadcast_mask) && bc)
+                                clockevents_shutdown(bc);
+                        /*
+                         * If we kept the cpu in the broadcast mask,
+                         * tell the caller to leave the per cpu device
+                         * in shutdown state. The periodic interrupt
+                         * is delivered by the broadcast device.
+                         */
+                        ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
+                        break;
+                default:
+                        /* Nothing to do */
+                        ret = 0;
+                        break;
                 }
         }
         raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -281,6 +342,7 @@ static void tick_do_broadcast_on_off(unsigned long *reason)
         switch (*reason) {
         case CLOCK_EVT_NOTIFY_BROADCAST_ON:
         case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
+                cpumask_set_cpu(cpu, tick_broadcast_on);
                 if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_mask)) {
                         if (tick_broadcast_device.mode ==
                             TICKDEV_MODE_PERIODIC)
@@ -290,8 +352,12 @@ static void tick_do_broadcast_on_off(unsigned long *reason)
                         tick_broadcast_force = 1;
                 break;
         case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
-                if (!tick_broadcast_force &&
-                    cpumask_test_and_clear_cpu(cpu, tick_broadcast_mask)) {
+                if (tick_broadcast_force)
+                        break;
+                cpumask_clear_cpu(cpu, tick_broadcast_on);
+                if (!tick_device_is_functional(dev))
+                        break;
+                if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_mask)) {
                         if (tick_broadcast_device.mode ==
                             TICKDEV_MODE_PERIODIC)
                                 tick_setup_periodic(dev, 0);
@@ -349,6 +415,7 @@ void tick_shutdown_broadcast(unsigned int *cpup)
 
         bc = tick_broadcast_device.evtdev;
         cpumask_clear_cpu(cpu, tick_broadcast_mask);
+        cpumask_clear_cpu(cpu, tick_broadcast_on);
 
         if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
                 if (bc && cpumask_empty(tick_broadcast_mask))
@@ -475,7 +542,15 @@ void tick_check_oneshot_broadcast(int cpu)
         if (cpumask_test_cpu(cpu, tick_broadcast_oneshot_mask)) {
                 struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
 
-                clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT);
+                /*
+                 * We might be in the middle of switching over from
+                 * periodic to oneshot. If the CPU has not yet
+                 * switched over, leave the device alone.
+                 */
+                if (td->mode == TICKDEV_MODE_ONESHOT) {
+                        clockevents_set_mode(td->evtdev,
+                                             CLOCK_EVT_MODE_ONESHOT);
+                }
         }
 }
 
@@ -522,6 +597,13 @@ again:
         cpumask_clear(tick_broadcast_force_mask);
 
         /*
+         * Sanity check. Catch the case where we try to broadcast to
+         * offline cpus.
+         */
+        if (WARN_ON_ONCE(!cpumask_subset(tmpmask, cpu_online_mask)))
+                cpumask_and(tmpmask, tmpmask, cpu_online_mask);
+
+        /*
          * Wakeup the cpus which have an expired event.
          */
         tick_do_broadcast(tmpmask);
@@ -761,10 +843,12 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
         raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
 
         /*
-         * Clear the broadcast mask flag for the dead cpu, but do not
-         * stop the broadcast device!
+         * Clear the broadcast masks for the dead cpu, but do not stop
+         * the broadcast device!
          */
         cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
+        cpumask_clear_cpu(cpu, tick_broadcast_pending_mask);
+        cpumask_clear_cpu(cpu, tick_broadcast_force_mask);
 
         raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
@@ -792,6 +876,7 @@ bool tick_broadcast_oneshot_available(void)
 void __init tick_broadcast_init(void)
 {
         zalloc_cpumask_var(&tick_broadcast_mask, GFP_NOWAIT);
+        zalloc_cpumask_var(&tick_broadcast_on, GFP_NOWAIT);
         zalloc_cpumask_var(&tmpmask, GFP_NOWAIT);
 #ifdef CONFIG_TICK_ONESHOT
         zalloc_cpumask_var(&tick_broadcast_oneshot_mask, GFP_NOWAIT);
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 5d3fb100bc06..64522ecdfe0e 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -18,6 +18,7 @@
 #include <linux/percpu.h>
 #include <linux/profile.h>
 #include <linux/sched.h>
+#include <linux/module.h>
 
 #include <asm/irq_regs.h>
 
@@ -33,7 +34,6 @@ DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
 ktime_t tick_next_period;
 ktime_t tick_period;
 int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
-static DEFINE_RAW_SPINLOCK(tick_device_lock);
 
 /*
  * Debugging: see timer_list.c
@@ -194,7 +194,8 @@ static void tick_setup_device(struct tick_device *td,
          * When global broadcasting is active, check if the current
          * device is registered as a placeholder for broadcast mode.
          * This allows us to handle this x86 misfeature in a generic
-         * way.
+         * way. This function also returns !=0 when we keep the
+         * current active broadcast state for this CPU.
          */
         if (tick_device_uses_broadcast(newdev, cpu))
                 return;
@@ -205,17 +206,75 @@ static void tick_setup_device(struct tick_device *td,
                 tick_setup_oneshot(newdev, handler, next_event);
 }
 
+void tick_install_replacement(struct clock_event_device *newdev)
+{
+        struct tick_device *td = &__get_cpu_var(tick_cpu_device);
+        int cpu = smp_processor_id();
+
+        clockevents_exchange_device(td->evtdev, newdev);
+        tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
+        if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
+                tick_oneshot_notify();
+}
+
+static bool tick_check_percpu(struct clock_event_device *curdev,
+                              struct clock_event_device *newdev, int cpu)
+{
+        if (!cpumask_test_cpu(cpu, newdev->cpumask))
+                return false;
+        if (cpumask_equal(newdev->cpumask, cpumask_of(cpu)))
+                return true;
+        /* Check if irq affinity can be set */
+        if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq))
+                return false;
+        /* Prefer an existing cpu local device */
+        if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))
+                return false;
+        return true;
+}
+
+static bool tick_check_preferred(struct clock_event_device *curdev,
+                                 struct clock_event_device *newdev)
+{
+        /* Prefer oneshot capable device */
+        if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) {
+                if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT))
+                        return false;
+                if (tick_oneshot_mode_active())
+                        return false;
+        }
+
+        /*
+         * Use the higher rated one, but prefer a CPU local device with a lower
+         * rating than a non-CPU local device
+         */
+        return !curdev ||
+                newdev->rating > curdev->rating ||
+               !cpumask_equal(curdev->cpumask, newdev->cpumask);
+}
+
+/*
+ * Check whether the new device is a better fit than curdev. curdev
+ * can be NULL !
+ */
+bool tick_check_replacement(struct clock_event_device *curdev,
+                            struct clock_event_device *newdev)
+{
+        if (tick_check_percpu(curdev, newdev, smp_processor_id()))
+                return false;
+
+        return tick_check_preferred(curdev, newdev);
+}
+
 /*
- * Check, if the new registered device should be used.
+ * Check, if the new registered device should be used. Called with
+ * clockevents_lock held and interrupts disabled.
  */
-static int tick_check_new_device(struct clock_event_device *newdev)
+void tick_check_new_device(struct clock_event_device *newdev)
 {
         struct clock_event_device *curdev;
         struct tick_device *td;
-        int cpu, ret = NOTIFY_OK;
-        unsigned long flags;
-
-        raw_spin_lock_irqsave(&tick_device_lock, flags);
+        int cpu;
 
         cpu = smp_processor_id();
         if (!cpumask_test_cpu(cpu, newdev->cpumask))
@@ -225,40 +284,15 @@ static int tick_check_new_device(struct clock_event_device *newdev)
         curdev = td->evtdev;
 
         /* cpu local device ? */
-        if (!cpumask_equal(newdev->cpumask, cpumask_of(cpu))) {
-
-                /*
-                 * If the cpu affinity of the device interrupt can not
-                 * be set, ignore it.
-                 */
-                if (!irq_can_set_affinity(newdev->irq))
-                        goto out_bc;
+        if (!tick_check_percpu(curdev, newdev, cpu))
+                goto out_bc;
 
-                /*
-                 * If we have a cpu local device already, do not replace it
-                 * by a non cpu local device
-                 */
-                if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))
-                        goto out_bc;
-        }
+        /* Preference decision */
+        if (!tick_check_preferred(curdev, newdev))
+                goto out_bc;
 
-        /*
-         * If we have an active device, then check the rating and the oneshot
-         * feature.
-         */
-        if (curdev) {
-                /*
-                 * Prefer one shot capable devices !
-                 */
-                if ((curdev->features & CLOCK_EVT_FEAT_ONESHOT) &&
-                    !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
-                        goto out_bc;
-                /*
-                 * Check the rating
-                 */
-                if (curdev->rating >= newdev->rating)
-                        goto out_bc;
-        }
+        if (!try_module_get(newdev->owner))
+                return;
 
         /*
          * Replace the eventually existing device by the new
@@ -273,20 +307,13 @@ static int tick_check_new_device(struct clock_event_device *newdev)
         tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
         if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
                 tick_oneshot_notify();
-
-        raw_spin_unlock_irqrestore(&tick_device_lock, flags);
-        return NOTIFY_STOP;
+        return;
 
 out_bc:
         /*
          * Can the new device be used as a broadcast device ?
          */
-        if (tick_check_broadcast_device(newdev))
-                ret = NOTIFY_STOP;
-
-        raw_spin_unlock_irqrestore(&tick_device_lock, flags);
-
-        return ret;
+        tick_install_broadcast_device(newdev);
 }
 
 /*
@@ -294,7 +321,7 @@ out_bc:
  *
  * Called with interrupts disabled.
  */
-static void tick_handover_do_timer(int *cpup)
+void tick_handover_do_timer(int *cpup)
 {
         if (*cpup == tick_do_timer_cpu) {
                 int cpu = cpumask_first(cpu_online_mask);
@@ -311,13 +338,11 @@ static void tick_handover_do_timer(int *cpup)
  * access the hardware device itself.
  * We just set the mode and remove it from the lists.
  */
-static void tick_shutdown(unsigned int *cpup)
+void tick_shutdown(unsigned int *cpup)
 {
         struct tick_device *td = &per_cpu(tick_cpu_device, *cpup);
         struct clock_event_device *dev = td->evtdev;
-        unsigned long flags;
 
-        raw_spin_lock_irqsave(&tick_device_lock, flags);
         td->mode = TICKDEV_MODE_PERIODIC;
         if (dev) {
                 /*
@@ -329,26 +354,20 @@ static void tick_shutdown(unsigned int *cpup)
                 dev->event_handler = clockevents_handle_noop;
                 td->evtdev = NULL;
         }
-        raw_spin_unlock_irqrestore(&tick_device_lock, flags);
 }
 
-static void tick_suspend(void)
+void tick_suspend(void)
 {
         struct tick_device *td = &__get_cpu_var(tick_cpu_device);
-        unsigned long flags;
 
-        raw_spin_lock_irqsave(&tick_device_lock, flags);
         clockevents_shutdown(td->evtdev);
-        raw_spin_unlock_irqrestore(&tick_device_lock, flags);
 }
 
-static void tick_resume(void)
+void tick_resume(void)
 {
         struct tick_device *td = &__get_cpu_var(tick_cpu_device);
-        unsigned long flags;
         int broadcast = tick_resume_broadcast();
 
-        raw_spin_lock_irqsave(&tick_device_lock, flags);
         clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME);
 
         if (!broadcast) {
@@ -357,68 +376,12 @@ static void tick_resume(void)
                 else
                         tick_resume_oneshot();
         }
-        raw_spin_unlock_irqrestore(&tick_device_lock, flags);
 }
 
-/*
- * Notification about clock event devices
- */
-static int tick_notify(struct notifier_block *nb, unsigned long reason,
-                               void *dev)
-{
-        switch (reason) {
-
-        case CLOCK_EVT_NOTIFY_ADD:
-                return tick_check_new_device(dev);
-
-        case CLOCK_EVT_NOTIFY_BROADCAST_ON:
-        case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
-        case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
-                tick_broadcast_on_off(reason, dev);
-                break;
-
-        case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:
-        case CLOCK_EVT_NOTIFY_BROADCAST_EXIT:
-                tick_broadcast_oneshot_control(reason);
-                break;
-
-        case CLOCK_EVT_NOTIFY_CPU_DYING:
-                tick_handover_do_timer(dev);
-                break;
-
-        case CLOCK_EVT_NOTIFY_CPU_DEAD:
-                tick_shutdown_broadcast_oneshot(dev);
-                tick_shutdown_broadcast(dev);
-                tick_shutdown(dev);
-                break;
-
-        case CLOCK_EVT_NOTIFY_SUSPEND:
-                tick_suspend();
-                tick_suspend_broadcast();
-                break;
-
-        case CLOCK_EVT_NOTIFY_RESUME:
-                tick_resume();
-                break;
-
-        default:
-                break;
-        }
-
-        return NOTIFY_OK;
-}
-
-static struct notifier_block tick_notifier = {
-        .notifier_call = tick_notify,
-};
-
 /**
  * tick_init - initialize the tick control
- *
- * Register the notifier with the clockevents framework
  */
 void __init tick_init(void)
 {
-        clockevents_register_notifier(&tick_notifier);
         tick_broadcast_init();
 }
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f0299eae4602..bc906cad709b 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -6,6 +6,8 @@
 
 extern seqlock_t jiffies_lock;
 
+#define CS_NAME_LEN     32
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BUILD
 
 #define TICK_DO_TIMER_NONE      -1
@@ -18,9 +20,19 @@ extern int tick_do_timer_cpu __read_mostly;
 
 extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast);
 extern void tick_handle_periodic(struct clock_event_device *dev);
+extern void tick_check_new_device(struct clock_event_device *dev);
+extern void tick_handover_do_timer(int *cpup);
+extern void tick_shutdown(unsigned int *cpup);
+extern void tick_suspend(void);
+extern void tick_resume(void);
+extern bool tick_check_replacement(struct clock_event_device *curdev,
+                                   struct clock_event_device *newdev);
+extern void tick_install_replacement(struct clock_event_device *dev);
 
 extern void clockevents_shutdown(struct clock_event_device *dev);
 
+extern size_t sysfs_get_uname(const char *buf, char *dst, size_t cnt);
+
 /*
  * NO_HZ / high resolution timer shared code
  */
@@ -90,7 +102,7 @@ static inline bool tick_broadcast_oneshot_available(void) { return false; }
  */
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 extern int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu);
-extern int tick_check_broadcast_device(struct clock_event_device *dev);
+extern void tick_install_broadcast_device(struct clock_event_device *dev);
 extern int tick_is_broadcast_device(struct clock_event_device *dev);
 extern void tick_broadcast_on_off(unsigned long reason, int *oncpu);
 extern void tick_shutdown_broadcast(unsigned int *cpup);
@@ -102,9 +114,8 @@ tick_set_periodic_handler(struct clock_event_device *dev, int broadcast);
 
 #else /* !BROADCAST */
 
-static inline int tick_check_broadcast_device(struct clock_event_device *dev)
+static inline void tick_install_broadcast_device(struct clock_event_device *dev)
 {
-        return 0;
 }
 
 static inline int tick_is_broadcast_device(struct clock_event_device *dev)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 0cf1c1453181..e8a1516cc0a3 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -178,6 +178,12 @@ static bool can_stop_full_tick(void)
          */
         if (!sched_clock_stable) {
                 trace_tick_stop(0, "unstable sched clock\n");
+                /*
+                 * Don't allow the user to think they can get
+                 * full NO_HZ with this machine.
+                 */
+                WARN_ONCE(have_nohz_full_mask,
+                          "NO_HZ FULL will not work with unstable sched clock");
                 return false;
         }
 #endif
@@ -293,7 +299,7 @@ static int __init tick_nohz_full_setup(char *str)
 }
 __setup("nohz_full=", tick_nohz_full_setup);
 
-static int __cpuinit tick_nohz_cpu_down_callback(struct notifier_block *nfb,
+static int tick_nohz_cpu_down_callback(struct notifier_block *nfb,
                                                  unsigned long action,
                                                  void *hcpu)
 {
@@ -338,24 +344,12 @@ static int tick_nohz_init_all(void)
 
 void __init tick_nohz_init(void)
 {
-        int cpu;
-
         if (!have_nohz_full_mask) {
                 if (tick_nohz_init_all() < 0)
                         return;
         }
 
         cpu_notifier(tick_nohz_cpu_down_callback, 0);
-
-        /* Make sure full dynticks CPU are also RCU nocbs */
-        for_each_cpu(cpu, nohz_full_mask) {
-                if (!rcu_is_nocb_cpu(cpu)) {
-                        pr_warning("NO_HZ: CPU %d is not RCU nocb: "
-                                   "cleared from nohz_full range", cpu);
-                        cpumask_clear_cpu(cpu, nohz_full_mask);
-                }
-        }
-
         cpulist_scnprintf(nohz_full_buf, sizeof(nohz_full_buf), nohz_full_mask);
         pr_info("NO_HZ: Full dynticks CPUs: %s.\n", nohz_full_buf);
 }
@@ -832,13 +826,10 @@ void tick_nohz_irq_exit(void)
 {
         struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
 
-        if (ts->inidle) {
-                /* Cancel the timer because CPU already waken up from the C-states*/
-                menu_hrtimer_cancel();
+        if (ts->inidle)
                 __tick_nohz_idle_enter(ts);
-        } else {
+        else
                 tick_nohz_full_stop_tick(ts);
-        }
 }
 
 /**
@@ -936,8 +927,6 @@ void tick_nohz_idle_exit(void)
 
         ts->inidle = 0;
 
-        /* Cancel the timer because CPU already waken up from the C-states*/
-        menu_hrtimer_cancel();
         if (ts->idle_active || ts->tick_stopped)
                 now = ktime_get();
 
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index baeeb5c87cf1..48b9fffabdc2 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -25,6 +25,11 @@
 
 #include "tick-internal.h"
 #include "ntp_internal.h"
+#include "timekeeping_internal.h"
+
+#define TK_CLEAR_NTP            (1 << 0)
+#define TK_MIRROR               (1 << 1)
+#define TK_CLOCK_WAS_SET        (1 << 2)
 
 static struct timekeeper timekeeper;
 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
@@ -200,9 +205,9 @@ static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)
 
 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
 
-static void update_pvclock_gtod(struct timekeeper *tk)
+static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
 {
-        raw_notifier_call_chain(&pvclock_gtod_chain, 0, tk);
+        raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
 }
 
 /**
@@ -216,7 +221,7 @@ int pvclock_gtod_register_notifier(struct notifier_block *nb)
 
         raw_spin_lock_irqsave(&timekeeper_lock, flags);
         ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
-        update_pvclock_gtod(tk);
+        update_pvclock_gtod(tk, true);
         raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 
         return ret;
@@ -241,16 +246,16 @@ int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
 
 /* must hold timekeeper_lock */
-static void timekeeping_update(struct timekeeper *tk, bool clearntp, bool mirror)
+static void timekeeping_update(struct timekeeper *tk, unsigned int action)
 {
-        if (clearntp) {
+        if (action & TK_CLEAR_NTP) {
                 tk->ntp_error = 0;
                 ntp_clear();
         }
         update_vsyscall(tk);
-        update_pvclock_gtod(tk);
+        update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
 
-        if (mirror)
+        if (action & TK_MIRROR)
                 memcpy(&shadow_timekeeper, &timekeeper, sizeof(timekeeper));
 }
 
@@ -508,7 +513,7 @@ int do_settimeofday(const struct timespec *tv)
 
         tk_set_xtime(tk, tv);
 
-        timekeeping_update(tk, true, true);
+        timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
 
         write_seqcount_end(&timekeeper_seq);
         raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
@@ -552,7 +557,7 @@ int timekeeping_inject_offset(struct timespec *ts)
         tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *ts));
 
 error: /* even if we error out, we forwarded the time, so call update */
-        timekeeping_update(tk, true, true);
+        timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
 
         write_seqcount_end(&timekeeper_seq);
         raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
@@ -627,13 +632,22 @@ static int change_clocksource(void *data)
         write_seqcount_begin(&timekeeper_seq);
 
         timekeeping_forward_now(tk);
-        if (!new->enable || new->enable(new) == 0) {
-                old = tk->clock;
-                tk_setup_internals(tk, new);
-                if (old->disable)
-                        old->disable(old);
+        /*
+         * If the cs is in module, get a module reference. Succeeds
+         * for built-in code (owner == NULL) as well.
+         */
+        if (try_module_get(new->owner)) {
+                if (!new->enable || new->enable(new) == 0) {
+                        old = tk->clock;
+                        tk_setup_internals(tk, new);
+                        if (old->disable)
+                                old->disable(old);
+                        module_put(old->owner);
+                } else {
+                        module_put(new->owner);
+                }
         }
-        timekeeping_update(tk, true, true);
+        timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
 
         write_seqcount_end(&timekeeper_seq);
         raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
@@ -648,14 +662,15 @@ static int change_clocksource(void *data)
  * This function is called from clocksource.c after a new, better clock
  * source has been registered. The caller holds the clocksource_mutex.
  */
-void timekeeping_notify(struct clocksource *clock)
+int timekeeping_notify(struct clocksource *clock)
 {
         struct timekeeper *tk = &timekeeper;
 
         if (tk->clock == clock)
-                return;
+                return 0;
         stop_machine(change_clocksource, clock, NULL);
         tick_clock_notify();
+        return tk->clock == clock ? 0 : -1;
 }
 
 /**
@@ -841,6 +856,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
         tk_xtime_add(tk, delta);
         tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *delta));
         tk_set_sleep_time(tk, timespec_add(tk->total_sleep_time, *delta));
+        tk_debug_account_sleep_time(delta);
 }
 
 /**
@@ -872,7 +888,7 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
 
         __timekeeping_inject_sleeptime(tk, delta);
 
-        timekeeping_update(tk, true, true);
+        timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
 
         write_seqcount_end(&timekeeper_seq);
         raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
@@ -954,7 +970,7 @@ static void timekeeping_resume(void)
         tk->cycle_last = clock->cycle_last = cycle_now;
         tk->ntp_error = 0;
         timekeeping_suspended = 0;
-        timekeeping_update(tk, false, true);
+        timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
         write_seqcount_end(&timekeeper_seq);
         raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 
@@ -1236,9 +1252,10 @@ out_adjust:
  * It also calls into the NTP code to handle leapsecond processing.
  *
  */
-static inline void accumulate_nsecs_to_secs(struct timekeeper *tk)
+static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
 {
         u64 nsecps = (u64)NSEC_PER_SEC << tk->shift;
+        unsigned int action = 0;
 
         while (tk->xtime_nsec >= nsecps) {
                 int leap;
@@ -1261,8 +1278,10 @@ static inline void accumulate_nsecs_to_secs(struct timekeeper *tk)
                         __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
 
                         clock_was_set_delayed();
+                        action = TK_CLOCK_WAS_SET;
                 }
         }
+        return action;
 }
 
 /**
@@ -1347,6 +1366,7 @@ static void update_wall_time(void)
         struct timekeeper *tk = &shadow_timekeeper;
         cycle_t offset;
         int shift = 0, maxshift;
+        unsigned int action;
         unsigned long flags;
 
         raw_spin_lock_irqsave(&timekeeper_lock, flags);
@@ -1399,7 +1419,7 @@ static void update_wall_time(void)
          * Finally, make sure that after the rounding
          * xtime_nsec isn't larger than NSEC_PER_SEC
          */
-        accumulate_nsecs_to_secs(tk);
+        action = accumulate_nsecs_to_secs(tk);
 
         write_seqcount_begin(&timekeeper_seq);
         /* Update clock->cycle_last with the new value */
@@ -1415,7 +1435,7 @@ static void update_wall_time(void)
          * updating.
          */
         memcpy(real_tk, tk, sizeof(*tk));
-        timekeeping_update(real_tk, false, false);
+        timekeeping_update(real_tk, action);
         write_seqcount_end(&timekeeper_seq);
 out:
         raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
@@ -1677,6 +1697,7 @@ int do_adjtimex(struct timex *txc)
 
         if (tai != orig_tai) {
                 __timekeeping_set_tai_offset(tk, tai);
+                update_pvclock_gtod(tk, true);
                 clock_was_set_delayed();
         }
         write_seqcount_end(&timekeeper_seq);
diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debug.c
new file mode 100644
index 000000000000..802433a4f5eb
--- /dev/null
+++ b/kernel/time/timekeeping_debug.c
@@ -0,0 +1,72 @@
+/*
+ * debugfs file to track time spent in suspend
+ *
+ * Copyright (c) 2011, Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/seq_file.h>
+#include <linux/time.h>
+
+static unsigned int sleep_time_bin[32] = {0};
+
+static int tk_debug_show_sleep_time(struct seq_file *s, void *data)
+{
+        unsigned int bin;
+        seq_puts(s, "      time (secs)        count\n");
+        seq_puts(s, "------------------------------\n");
+        for (bin = 0; bin < 32; bin++) {
+                if (sleep_time_bin[bin] == 0)
+                        continue;
+                seq_printf(s, "%10u - %-10u %4u\n",
+                        bin ? 1 << (bin - 1) : 0, 1 << bin,
+                                sleep_time_bin[bin]);
+        }
+        return 0;
+}
+
+static int tk_debug_sleep_time_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, tk_debug_show_sleep_time, NULL);
+}
+
+static const struct file_operations tk_debug_sleep_time_fops = {
+        .open           = tk_debug_sleep_time_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+static int __init tk_debug_sleep_time_init(void)
+{
+        struct dentry *d;
+
+        d = debugfs_create_file("sleep_time", 0444, NULL, NULL,
+                &tk_debug_sleep_time_fops);
+        if (!d) {
+                pr_err("Failed to create sleep_time debug file\n");
+                return -ENOMEM;
+        }
+
+        return 0;
+}
+late_initcall(tk_debug_sleep_time_init);
+
+void tk_debug_account_sleep_time(struct timespec *t)
+{
+        sleep_time_bin[fls(t->tv_sec)]++;
+}
+
diff --git a/kernel/time/timekeeping_internal.h b/kernel/time/timekeeping_internal.h
new file mode 100644
index 000000000000..13323ea08ffa
--- /dev/null
+++ b/kernel/time/timekeeping_internal.h
@@ -0,0 +1,14 @@
+#ifndef _TIMEKEEPING_INTERNAL_H
+#define _TIMEKEEPING_INTERNAL_H
+/*
+ * timekeeping debug functions
+ */
+#include <linux/time.h>
+
+#ifdef CONFIG_DEBUG_FS
+extern void tk_debug_account_sleep_time(struct timespec *t);
+#else
+#define tk_debug_account_sleep_time(x)
+#endif
+
+#endif /* _TIMEKEEPING_INTERNAL_H */
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index 3bdf28323012..61ed862cdd37 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -265,10 +265,9 @@ static inline void timer_list_header(struct seq_file *m, u64 now)
 static int timer_list_show(struct seq_file *m, void *v)
 {
         struct timer_list_iter *iter = v;
-        u64 now = ktime_to_ns(ktime_get());
 
         if (iter->cpu == -1 && !iter->second_pass)
-                timer_list_header(m, now);
+                timer_list_header(m, iter->now);
         else if (!iter->second_pass)
                 print_cpu(m, iter->cpu, iter->now);
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
@@ -298,33 +297,41 @@ void sysrq_timer_list_show(void)
         return;
 }
 
-static void *timer_list_start(struct seq_file *file, loff_t *offset)
+static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 {
-        struct timer_list_iter *iter = file->private;
-
-        if (!*offset) {
-                iter->cpu = -1;
-                iter->now = ktime_to_ns(ktime_get());
-        } else if (iter->cpu >= nr_cpu_ids) {
+        for (; offset; offset--) {
+                iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
+                if (iter->cpu >= nr_cpu_ids) {
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
-                if (!iter->second_pass) {
-                        iter->cpu = -1;
-                        iter->second_pass = true;
-                } else
-                        return NULL;
+                        if (!iter->second_pass) {
+                                iter->cpu = -1;
+                                iter->second_pass = true;
+                        } else
+                                return NULL;
 #else
-                return NULL;
+                        return NULL;
 #endif
+                }
         }
         return iter;
 }
 
+static void *timer_list_start(struct seq_file *file, loff_t *offset)
+{
+        struct timer_list_iter *iter = file->private;
+
+        if (!*offset)
+                iter->now = ktime_to_ns(ktime_get());
+        iter->cpu = -1;
+        iter->second_pass = false;
+        return move_iter(iter, *offset);
+}
+
 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 {
         struct timer_list_iter *iter = file->private;
-        iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
         ++*offset;
-        return timer_list_start(file, offset);
+        return move_iter(iter, 1);
 }
 
 static void timer_list_stop(struct seq_file *seq, void *v)