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

Pull timer changes from Thomas Gleixner:
 "This assorted collection provides:

   - A new timer based timer broadcast feature for systems which do not
     provide a global accessible timer device.  That allows those
     systems to put CPUs into deep idle states where the per cpu timer
     device stops.

   - A few NOHZ_FULL related improvements to the timer wheel

   - The usual updates to timer devices found in ARM SoCs

   - Small improvements and updates all over the place"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
  tick: Remove code duplication in tick_handle_periodic()
  tick: Fix spelling mistake in tick_handle_periodic()
  x86: hpet: Use proper destructor for delayed work
  workqueue: Provide destroy_delayed_work_on_stack()
  clocksource: CMT, MTU2, TMU and STI should depend on GENERIC_CLOCKEVENTS
  timer: Remove code redundancy while calling get_nohz_timer_target()
  hrtimer: Rearrange comments in the order struct members are declared
  timer: Use variable head instead of &work_list in __run_timers()
  clocksource: exynos_mct: silence a static checker warning
  arm: zynq: Add support for cpufreq
  arm: zynq: Don't use arm_global_timer with cpufreq
  clocksource/cadence_ttc: Overhaul clocksource frequency adjustment
  clocksource/cadence_ttc: Call clockevents_update_freq() with IRQs enabled
  clocksource: Add Kconfig entries for CMT, MTU2, TMU and STI
  sh: Remove Kconfig entries for TMU, CMT and MTU2
  ARM: shmobile: Remove CMT, TMU and STI Kconfig entries
  clocksource: armada-370-xp: Use atomic access for shared registers
  clocksource: orion: Use atomic access for shared registers
  clocksource: timer-keystone: Delete unnecessary variable
  clocksource: timer-keystone: introduce clocksource driver for Keystone
  ...

kernel/time/Kconfig

@@ -124,7 +124,7 @@ config NO_HZ_FULL
 endchoice
 
 config NO_HZ_FULL_ALL
-       bool "Full dynticks system on all CPUs by default"
+       bool "Full dynticks system on all CPUs by default (except CPU 0)"
        depends on NO_HZ_FULL
        help
          If the user doesn't pass the nohz_full boot option to

kernel/time/Makefile

@@ -3,7 +3,10 @@ obj-y += timeconv.o posix-clock.o alarmtimer.o
 
 obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD)		+= clockevents.o
 obj-$(CONFIG_GENERIC_CLOCKEVENTS)		+= tick-common.o
-obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)	+= tick-broadcast.o
+ifeq ($(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST),y)
+ obj-y						+= tick-broadcast.o
+ obj-$(CONFIG_TICK_ONESHOT)			+= tick-broadcast-hrtimer.o
+endif
 obj-$(CONFIG_GENERIC_SCHED_CLOCK)		+= sched_clock.o
 obj-$(CONFIG_TICK_ONESHOT)			+= tick-oneshot.o
 obj-$(CONFIG_TICK_ONESHOT)			+= tick-sched.o

kernel/time/clockevents.c

@@ -439,6 +439,19 @@ void clockevents_config_and_register(struct clock_event_device *dev,
 }
 EXPORT_SYMBOL_GPL(clockevents_config_and_register);
 
+int __clockevents_update_freq(struct clock_event_device *dev, u32 freq)
+{
+	clockevents_config(dev, freq);
+
+	if (dev->mode == CLOCK_EVT_MODE_ONESHOT)
+		return clockevents_program_event(dev, dev->next_event, false);
+
+	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
+		dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev);
+
+	return 0;
+}
+
 /**
  * clockevents_update_freq - Update frequency and reprogram a clock event device.
  * @dev:	device to modify
@@ -446,17 +459,22 @@ EXPORT_SYMBOL_GPL(clockevents_config_and_register);
  *
  * Reconfigure and reprogram a clock event device in oneshot
  * mode. Must be called on the cpu for which the device delivers per
- * cpu timer events with interrupts disabled!  Returns 0 on success,
- * -ETIME when the event is in the past.
+ * cpu timer events. If called for the broadcast device the core takes
+ * care of serialization.
+ *
+ * Returns 0 on success, -ETIME when the event is in the past.
  */
 int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
 {
-	clockevents_config(dev, freq);
+	unsigned long flags;
+	int ret;
 
-	if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
-		return 0;
-
-	return clockevents_program_event(dev, dev->next_event, false);
+	local_irq_save(flags);
+	ret = tick_broadcast_update_freq(dev, freq);
+	if (ret == -ENODEV)
+		ret = __clockevents_update_freq(dev, freq);
+	local_irq_restore(flags);
+	return ret;
 }
 
 /*
@@ -524,12 +542,13 @@ void clockevents_resume(void)
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 /**
  * clockevents_notify - notification about relevant events
+ * Returns 0 on success, any other value on error
  */
-void clockevents_notify(unsigned long reason, void *arg)
+int clockevents_notify(unsigned long reason, void *arg)
 {
 	struct clock_event_device *dev, *tmp;
 	unsigned long flags;
-	int cpu;
+	int cpu, ret = 0;
 
 	raw_spin_lock_irqsave(&clockevents_lock, flags);
 
@@ -542,7 +561,7 @@ void clockevents_notify(unsigned long reason, void *arg)
 
 	case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:
 	case CLOCK_EVT_NOTIFY_BROADCAST_EXIT:
-		tick_broadcast_oneshot_control(reason);
+		ret = tick_broadcast_oneshot_control(reason);
 		break;
 
 	case CLOCK_EVT_NOTIFY_CPU_DYING:
@@ -585,6 +604,7 @@ void clockevents_notify(unsigned long reason, void *arg)
 		break;
 	}
 	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(clockevents_notify);
 

kernel/time/ntp.c

@@ -514,12 +514,13 @@ static void sync_cmos_clock(struct work_struct *work)
 		next.tv_sec++;
 		next.tv_nsec -= NSEC_PER_SEC;
 	}
-	schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
+	queue_delayed_work(system_power_efficient_wq,
+			   &sync_cmos_work, timespec_to_jiffies(&next));
 }
 
 void ntp_notify_cmos_timer(void)
 {
-	schedule_delayed_work(&sync_cmos_work, 0);
+	queue_delayed_work(system_power_efficient_wq, &sync_cmos_work, 0);
 }
 
 #else

kernel/time/tick-broadcast-hrtimer.c

@@ -0,0 +1,106 @@
+/*
+ * linux/kernel/time/tick-broadcast-hrtimer.c
+ * This file emulates a local clock event device
+ * via a pseudo clock device.
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/profile.h>
+#include <linux/clockchips.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/module.h>
+
+#include "tick-internal.h"
+
+static struct hrtimer bctimer;
+
+static void bc_set_mode(enum clock_event_mode mode,
+			struct clock_event_device *bc)
+{
+	switch (mode) {
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		/*
+		 * Note, we cannot cancel the timer here as we might
+		 * run into the following live lock scenario:
+		 *
+		 * cpu 0		cpu1
+		 * lock(broadcast_lock);
+		 *			hrtimer_interrupt()
+		 *			bc_handler()
+		 *			   tick_handle_oneshot_broadcast();
+		 *			    lock(broadcast_lock);
+		 * hrtimer_cancel()
+		 *  wait_for_callback()
+		 */
+		hrtimer_try_to_cancel(&bctimer);
+		break;
+	default:
+		break;
+	}
+}
+
+/*
+ * This is called from the guts of the broadcast code when the cpu
+ * which is about to enter idle has the earliest broadcast timer event.
+ */
+static int bc_set_next(ktime_t expires, struct clock_event_device *bc)
+{
+	/*
+	 * We try to cancel the timer first. If the callback is on
+	 * flight on some other cpu then we let it handle it. If we
+	 * were able to cancel the timer nothing can rearm it as we
+	 * own broadcast_lock.
+	 *
+	 * However we can also be called from the event handler of
+	 * ce_broadcast_hrtimer itself when it expires. We cannot
+	 * restart the timer because we are in the callback, but we
+	 * can set the expiry time and let the callback return
+	 * HRTIMER_RESTART.
+	 */
+	if (hrtimer_try_to_cancel(&bctimer) >= 0) {
+		hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED);
+		/* Bind the "device" to the cpu */
+		bc->bound_on = smp_processor_id();
+	} else if (bc->bound_on == smp_processor_id()) {
+		hrtimer_set_expires(&bctimer, expires);
+	}
+	return 0;
+}
+
+static struct clock_event_device ce_broadcast_hrtimer = {
+	.set_mode		= bc_set_mode,
+	.set_next_ktime		= bc_set_next,
+	.features		= CLOCK_EVT_FEAT_ONESHOT |
+				  CLOCK_EVT_FEAT_KTIME |
+				  CLOCK_EVT_FEAT_HRTIMER,
+	.rating			= 0,
+	.bound_on		= -1,
+	.min_delta_ns		= 1,
+	.max_delta_ns		= KTIME_MAX,
+	.min_delta_ticks	= 1,
+	.max_delta_ticks	= ULONG_MAX,
+	.mult			= 1,
+	.shift			= 0,
+	.cpumask		= cpu_all_mask,
+};
+
+static enum hrtimer_restart bc_handler(struct hrtimer *t)
+{
+	ce_broadcast_hrtimer.event_handler(&ce_broadcast_hrtimer);
+
+	if (ce_broadcast_hrtimer.next_event.tv64 == KTIME_MAX)
+		return HRTIMER_NORESTART;
+
+	return HRTIMER_RESTART;
+}
+
+void tick_setup_hrtimer_broadcast(void)
+{
+	hrtimer_init(&bctimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	bctimer.function = bc_handler;
+	clockevents_register_device(&ce_broadcast_hrtimer);
+}

kernel/time/tick-broadcast.c

@@ -120,6 +120,19 @@ int tick_is_broadcast_device(struct clock_event_device *dev)
 	return (dev && tick_broadcast_device.evtdev == dev);
 }
 
+int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq)
+{
+	int ret = -ENODEV;
+
+	if (tick_is_broadcast_device(dev)) {
+		raw_spin_lock(&tick_broadcast_lock);
+		ret = __clockevents_update_freq(dev, freq);
+		raw_spin_unlock(&tick_broadcast_lock);
+	}
+	return ret;
+}
+
+
 static void err_broadcast(const struct cpumask *mask)
 {
 	pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n");
@@ -272,12 +285,8 @@ static void tick_do_broadcast(struct cpumask *mask)
  */
 static void tick_do_periodic_broadcast(void)
 {
-	raw_spin_lock(&tick_broadcast_lock);
-
 	cpumask_and(tmpmask, cpu_online_mask, tick_broadcast_mask);
 	tick_do_broadcast(tmpmask);
-
-	raw_spin_unlock(&tick_broadcast_lock);
 }
 
 /*
@@ -287,13 +296,15 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 {
 	ktime_t next;
 
+	raw_spin_lock(&tick_broadcast_lock);
+
 	tick_do_periodic_broadcast();
 
 	/*
 	 * The device is in periodic mode. No reprogramming necessary:
 	 */
 	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
-		return;
+		goto unlock;
 
 	/*
 	 * Setup the next period for devices, which do not have
@@ -306,9 +317,11 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 		next = ktime_add(next, tick_period);
 
 		if (!clockevents_program_event(dev, next, false))
-			return;
+			goto unlock;
 		tick_do_periodic_broadcast();
 	}
+unlock:
+	raw_spin_unlock(&tick_broadcast_lock);
 }
 
 /*
@@ -630,24 +643,61 @@ again:
 	raw_spin_unlock(&tick_broadcast_lock);
 }
 
+static int broadcast_needs_cpu(struct clock_event_device *bc, int cpu)
+{
+	if (!(bc->features & CLOCK_EVT_FEAT_HRTIMER))
+		return 0;
+	if (bc->next_event.tv64 == KTIME_MAX)
+		return 0;
+	return bc->bound_on == cpu ? -EBUSY : 0;
+}
+
+static void broadcast_shutdown_local(struct clock_event_device *bc,
+				     struct clock_event_device *dev)
+{
+	/*
+	 * For hrtimer based broadcasting we cannot shutdown the cpu
+	 * local device if our own event is the first one to expire or
+	 * if we own the broadcast timer.
+	 */
+	if (bc->features & CLOCK_EVT_FEAT_HRTIMER) {
+		if (broadcast_needs_cpu(bc, smp_processor_id()))
+			return;
+		if (dev->next_event.tv64 < bc->next_event.tv64)
+			return;
+	}
+	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
+}
+
+static void broadcast_move_bc(int deadcpu)
+{
+	struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
+	if (!bc || !broadcast_needs_cpu(bc, deadcpu))
+		return;
+	/* This moves the broadcast assignment to this cpu */
+	clockevents_program_event(bc, bc->next_event, 1);
+}
+
 /*
  * Powerstate information: The system enters/leaves a state, where
  * affected devices might stop
+ * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups.
  */
-void tick_broadcast_oneshot_control(unsigned long reason)
+int tick_broadcast_oneshot_control(unsigned long reason)
 {
 	struct clock_event_device *bc, *dev;
 	struct tick_device *td;
 	unsigned long flags;
 	ktime_t now;
-	int cpu;
+	int cpu, ret = 0;
 
 	/*
 	 * Periodic mode does not care about the enter/exit of power
 	 * states
 	 */
 	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
-		return;
+		return 0;
 
 	/*
 	 * We are called with preemtion disabled from the depth of the
@@ -658,7 +708,7 @@ void tick_broadcast_oneshot_control(unsigned long reason)
 	dev = td->evtdev;
 
 	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
-		return;
+		return 0;
 
 	bc = tick_broadcast_device.evtdev;
 
@@ -666,7 +716,7 @@ void tick_broadcast_oneshot_control(unsigned long reason)
 	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
 		if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) {
 			WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
-			clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
+			broadcast_shutdown_local(bc, dev);
 			/*
 			 * We only reprogram the broadcast timer if we
 			 * did not mark ourself in the force mask and
@@ -679,6 +729,16 @@ void tick_broadcast_oneshot_control(unsigned long reason)
 			    dev->next_event.tv64 < bc->next_event.tv64)
 				tick_broadcast_set_event(bc, cpu, dev->next_event, 1);
 		}
+		/*
+		 * If the current CPU owns the hrtimer broadcast
+		 * mechanism, it cannot go deep idle and we remove the
+		 * CPU from the broadcast mask. We don't have to go
+		 * through the EXIT path as the local timer is not
+		 * shutdown.
+		 */
+		ret = broadcast_needs_cpu(bc, cpu);
+		if (ret)
+			cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
 	} else {
 		if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_oneshot_mask)) {
 			clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
@@ -746,6 +806,7 @@ void tick_broadcast_oneshot_control(unsigned long reason)
 	}
 out:
 	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+	return ret;
 }
 
 /*
@@ -852,6 +913,8 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
 	cpumask_clear_cpu(cpu, tick_broadcast_pending_mask);
 	cpumask_clear_cpu(cpu, tick_broadcast_force_mask);
 
+	broadcast_move_bc(cpu);
+
 	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
 

kernel/time/tick-common.c

@@ -98,18 +98,19 @@ static void tick_periodic(int cpu)
 void tick_handle_periodic(struct clock_event_device *dev)
 {
 	int cpu = smp_processor_id();
-	ktime_t next;
+	ktime_t next = dev->next_event;
 
 	tick_periodic(cpu);
 
 	if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
 		return;
-	/*
-	 * Setup the next period for devices, which do not have
-	 * periodic mode:
-	 */
-	next = ktime_add(dev->next_event, tick_period);
 	for (;;) {
+		/*
+		 * Setup the next period for devices, which do not have
+		 * periodic mode:
+		 */
+		next = ktime_add(next, tick_period);
+
 		if (!clockevents_program_event(dev, next, false))
 			return;
 		/*
@@ -118,12 +119,11 @@ void tick_handle_periodic(struct clock_event_device *dev)
 		 * to be sure we're using a real hardware clocksource.
 		 * Otherwise we could get trapped in an infinite
 		 * loop, as the tick_periodic() increments jiffies,
-		 * when then will increment time, posibly causing
+		 * which then will increment time, possibly causing
 		 * the loop to trigger again and again.
 		 */
 		if (timekeeping_valid_for_hres())
 			tick_periodic(cpu);
-		next = ktime_add(next, tick_period);
 	}
 }
 

kernel/time/tick-internal.h

@@ -46,7 +46,7 @@ extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
 extern void tick_resume_oneshot(void);
 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 extern void tick_broadcast_setup_oneshot(struct clock_event_device *bc);
-extern void tick_broadcast_oneshot_control(unsigned long reason);
+extern int tick_broadcast_oneshot_control(unsigned long reason);
 extern void tick_broadcast_switch_to_oneshot(void);
 extern void tick_shutdown_broadcast_oneshot(unsigned int *cpup);
 extern int tick_resume_broadcast_oneshot(struct clock_event_device *bc);
@@ -58,7 +58,7 @@ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
 	BUG();
 }
-static inline void tick_broadcast_oneshot_control(unsigned long reason) { }
+static inline int tick_broadcast_oneshot_control(unsigned long reason) { return 0; }
 static inline void tick_broadcast_switch_to_oneshot(void) { }
 static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { }
 static inline int tick_broadcast_oneshot_active(void) { return 0; }
@@ -87,7 +87,7 @@ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
 	BUG();
 }
-static inline void tick_broadcast_oneshot_control(unsigned long reason) { }
+static inline int tick_broadcast_oneshot_control(unsigned long reason) { return 0; }
 static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { }
 static inline int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
 {
@@ -111,6 +111,7 @@ extern int tick_resume_broadcast(void);
 extern void tick_broadcast_init(void);
 extern void
 tick_set_periodic_handler(struct clock_event_device *dev, int broadcast);
+int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq);
 
 #else /* !BROADCAST */
 
@@ -133,6 +134,8 @@ static inline void tick_shutdown_broadcast(unsigned int *cpup) { }
 static inline void tick_suspend_broadcast(void) { }
 static inline int tick_resume_broadcast(void) { return 0; }
 static inline void tick_broadcast_init(void) { }
+static inline int tick_broadcast_update_freq(struct clock_event_device *dev,
+					     u32 freq) { return -ENODEV; }
 
 /*
  * Set the periodic handler in non broadcast mode
@@ -152,6 +155,8 @@ static inline int tick_device_is_functional(struct clock_event_device *dev)
 	return !(dev->features & CLOCK_EVT_FEAT_DUMMY);
 }
 
+int __clockevents_update_freq(struct clock_event_device *dev, u32 freq);
+
 #endif
 
 extern void do_timer(unsigned long ticks);

kernel/time/timekeeping_debug.c

@@ -21,6 +21,8 @@
 #include <linux/seq_file.h>
 #include <linux/time.h>
 
+#include "timekeeping_internal.h"
+
 static unsigned int sleep_time_bin[32] = {0};
 
 static int tk_debug_show_sleep_time(struct seq_file *s, void *data)