5 files changed, 55 insertions, 5 deletions

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index d13be216a790..1ad6dd461119 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -18,6 +18,7 @@
 #include <linux/notifier.h>
 #include <linux/smp.h>
 #include <linux/sysdev.h>
+#include <linux/tick.h>
 
 /* The registered clock event devices */
 static LIST_HEAD(clockevent_devices);
@@ -54,6 +55,7 @@ unsigned long clockevent_delta2ns(unsigned long latch,
 
         return (unsigned long) clc;
 }
+EXPORT_SYMBOL_GPL(clockevent_delta2ns);
 
 /**
  * clockevents_set_mode - set the operating mode of a clock event device
@@ -187,6 +189,7 @@ void clockevents_register_device(struct clock_event_device *dev)
 
         spin_unlock(&clockevents_lock);
 }
+EXPORT_SYMBOL_GPL(clockevents_register_device);
 
 /*
  * Noop handler when we shut down an event device
@@ -251,4 +254,15 @@ void clockevents_notify(unsigned long reason, void *arg)
         spin_unlock(&clockevents_lock);
 }
 EXPORT_SYMBOL_GPL(clockevents_notify);
+
+ktime_t clockevents_get_next_event(int cpu)
+{
+        struct tick_device *td;
+        struct clock_event_device *dev;
+
+        td = &per_cpu(tick_cpu_device, cpu);
+        dev = td->evtdev;
+
+        return dev->next_event;
+}
 #endif
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 80189f6f1c5a..592bf584d1d2 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -509,6 +509,18 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev,
                 }
         }
 
+        /*
+         * Check to make sure we don't switch to a non-highres capable
+         * clocksource if the tick code is in oneshot mode (highres or nohz)
+         */
+        if (tick_oneshot_mode_active() &&
+            !(ovr->flags & CLOCK_SOURCE_VALID_FOR_HRES)) {
+                printk(KERN_WARNING "%s clocksource is not HRT compatible. "
+                        "Cannot switch while in HRT/NOHZ mode\n", ovr->name);
+                ovr = NULL;
+                override_name[0] = 0;
+        }
+
         /* Reselect, when the override name has changed */
         if (ovr != clocksource_override) {
                 clocksource_override = ovr;
@@ -537,7 +549,13 @@ sysfs_show_available_clocksources(struct sys_device *dev,
 
         spin_lock_irq(&clocksource_lock);
         list_for_each_entry(src, &clocksource_list, list) {
-                count += snprintf(buf + count,
+                /*
+                 * Don't show non-HRES clocksource if the tick code is
+                 * in one shot mode (highres=on or nohz=on)
+                 */
+                if (!tick_oneshot_mode_active() ||
+                    (src->flags & CLOCK_SOURCE_VALID_FOR_HRES))
+                        count += snprintf(buf + count,
                                   max((ssize_t)PAGE_SIZE - count, (ssize_t)0),
                                   "%s ", src->name);
         }
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 118a3b3b3f9a..877dbedc3118 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -27,7 +27,7 @@
  * timer stops in C3 state.
  */
 
-struct tick_device tick_broadcast_device;
+static struct tick_device tick_broadcast_device;
 /* FIXME: Use cpumask_var_t. */
 static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS);
 static DECLARE_BITMAP(tmpmask, NR_CPUS);
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 2e8de678e767..a96c0e2b89cf 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -128,6 +128,23 @@ int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *))
         return 0;
 }
 
+/**
+ * tick_check_oneshot_mode - check whether the system is in oneshot mode
+ *
+ * returns 1 when either nohz or highres are enabled. otherwise 0.
+ */
+int tick_oneshot_mode_active(void)
+{
+        unsigned long flags;
+        int ret;
+
+        local_irq_save(flags);
+        ret = __get_cpu_var(tick_cpu_device).mode == TICKDEV_MODE_ONESHOT;
+        local_irq_restore(flags);
+
+        return ret;
+}
+
 #ifdef CONFIG_HIGH_RES_TIMERS
 /**
  * tick_init_highres - switch to high resolution mode
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index d3f1ef4d5cbe..2aff39c6f10c 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -349,7 +349,7 @@ void tick_nohz_stop_sched_tick(int inidle)
 
                 if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
                         hrtimer_start(&ts->sched_timer, expires,
-                                      HRTIMER_MODE_ABS);
+                                      HRTIMER_MODE_ABS_PINNED);
                         /* Check, if the timer was already in the past */
                         if (hrtimer_active(&ts->sched_timer))
                                 goto out;
@@ -395,7 +395,7 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
 
                 if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
                         hrtimer_start_expires(&ts->sched_timer,
-                                      HRTIMER_MODE_ABS);
+                                              HRTIMER_MODE_ABS_PINNED);
                         /* Check, if the timer was already in the past */
                         if (hrtimer_active(&ts->sched_timer))
                                 break;
@@ -698,7 +698,8 @@ void tick_setup_sched_timer(void)
 
         for (;;) {
                 hrtimer_forward(&ts->sched_timer, now, tick_period);
-                hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS);
+                hrtimer_start_expires(&ts->sched_timer,
+                                      HRTIMER_MODE_ABS_PINNED);
                 /* Check, if the timer was already in the past */
                 if (hrtimer_active(&ts->sched_timer))
                         break;