[GIT pull] timer updates for 4.2

From: Thomas Gleixner
Date: Sun Jul 12 2015 - 02:24:06 EST

Linus,

please pull the latest timers-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-for-linus

This update from the timer departement contains:

- A series of patches which address a shortcoming in the tick
broadcast code. If the broadcast device is not available or an
hrtimer emulated broadcast device, some of the original
assumptions lead to boot failures. I rather plugged all of the
corner cases instead of only addressing the issue reported, so the
change got a little larger. Has been extensivly tested on x86 and
arm.

- Get rid of the last holdouts using do_posix_clock_monotonic_gettime()

- A regression fix for the imx clocksource driver

- An update to the new state callbacks mechanism for clockevents. This
is required to simplify the conversion, which will take place in 4.3

Thanks,

tglx

------------------>
Philippe Reynes (1):
clocksource/imx: Define clocksource for mx27

Thomas Gleixner (13):
tick/broadcast: Prevent hrtimer recursion
tick/broadcast: Sanity check the shutdown of the local clock_event
tick/broadcast: Make idle check independent from mode and config
tick/broadcast: Prevent deep idle if no broadcast device available
tick/broadcast: Move the check for periodic mode inside state handling
tick/broadcast: Return busy if periodic mode and hrtimer broadcast
tick/broadcast: Return busy when IPI is pending
tick/broadcast: Check for hrtimer broadcast active early
tick/broadcast: Handle spurious interrupts gracefully
tick/broadcast: Unbreak CONFIG_GENERIC_CLOCKEVENTS=n build
cris: Replace do_posix_clock_monotonic_gettime()
time: Get rid of do_posix_clock_monotonic_gettime
tick/broadcast: Prevent NULL pointer dereference

Viresh Kumar (1):
clockevents: Allow set-state callbacks to be optional


arch/cris/arch-v32/drivers/sync_serial.c | 2 +-
drivers/clocksource/timer-imx-gpt.c | 1 +
include/linux/tick.h | 7 +-
include/linux/timekeeping.h | 1 -
kernel/time/clockevents.c | 24 ++---
kernel/time/tick-broadcast.c | 163 ++++++++++++++++++++-----------
kernel/time/tick-common.c | 21 ++++
kernel/time/tick-sched.h | 10 ++
8 files changed, 155 insertions(+), 74 deletions(-)

diff --git a/arch/cris/arch-v32/drivers/sync_serial.c b/arch/cris/arch-v32/drivers/sync_serial.c
index 4dda9bd6b8fb..e989cee77414 100644
--- a/arch/cris/arch-v32/drivers/sync_serial.c
+++ b/arch/cris/arch-v32/drivers/sync_serial.c
@@ -1464,7 +1464,7 @@ static inline void handle_rx_packet(struct sync_port *port)
if (port->write_ts_idx == NBR_IN_DESCR)
port->write_ts_idx = 0;
idx = port->write_ts_idx++;
- do_posix_clock_monotonic_gettime(&port->timestamp[idx]);
+ ktime_get_ts(&port->timestamp[idx]);
port->in_buffer_len += port->inbufchunk;
}
spin_unlock_irqrestore(&port->lock, flags);
diff --git a/drivers/clocksource/timer-imx-gpt.c b/drivers/clocksource/timer-imx-gpt.c
index 879c78423546..2d59038dec43 100644
--- a/drivers/clocksource/timer-imx-gpt.c
+++ b/drivers/clocksource/timer-imx-gpt.c
@@ -529,6 +529,7 @@ static void __init imx6dl_timer_init_dt(struct device_node *np)

CLOCKSOURCE_OF_DECLARE(imx1_timer, "fsl,imx1-gpt", imx1_timer_init_dt);
CLOCKSOURCE_OF_DECLARE(imx21_timer, "fsl,imx21-gpt", imx21_timer_init_dt);
+CLOCKSOURCE_OF_DECLARE(imx27_timer, "fsl,imx27-gpt", imx21_timer_init_dt);
CLOCKSOURCE_OF_DECLARE(imx31_timer, "fsl,imx31-gpt", imx31_timer_init_dt);
CLOCKSOURCE_OF_DECLARE(imx25_timer, "fsl,imx25-gpt", imx31_timer_init_dt);
CLOCKSOURCE_OF_DECLARE(imx50_timer, "fsl,imx50-gpt", imx31_timer_init_dt);
diff --git a/include/linux/tick.h b/include/linux/tick.h
index 3741ba1a652c..edbfc9a5293e 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -67,10 +67,13 @@ extern void tick_broadcast_control(enum tick_broadcast_mode mode);
static inline void tick_broadcast_control(enum tick_broadcast_mode mode) { }
#endif /* BROADCAST */

-#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
extern int tick_broadcast_oneshot_control(enum tick_broadcast_state state);
#else
-static inline int tick_broadcast_oneshot_control(enum tick_broadcast_state state) { return 0; }
+static inline int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+ return 0;
+}
#endif

static inline void tick_broadcast_enable(void)
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 3aa72e648650..6e191e4e6ab6 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -145,7 +145,6 @@ static inline void getboottime(struct timespec *ts)
}
#endif

-#define do_posix_clock_monotonic_gettime(ts) ktime_get_ts(ts)
#define ktime_get_real_ts64(ts) getnstimeofday64(ts)

/*
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 08ccc3da3ca0..50eb107f1198 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -120,19 +120,25 @@ static int __clockevents_switch_state(struct clock_event_device *dev,
/* The clockevent device is getting replaced. Shut it down. */

case CLOCK_EVT_STATE_SHUTDOWN:
- return dev->set_state_shutdown(dev);
+ if (dev->set_state_shutdown)
+ return dev->set_state_shutdown(dev);
+ return 0;

case CLOCK_EVT_STATE_PERIODIC:
/* Core internal bug */
if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC))
return -ENOSYS;
- return dev->set_state_periodic(dev);
+ if (dev->set_state_periodic)
+ return dev->set_state_periodic(dev);
+ return 0;

case CLOCK_EVT_STATE_ONESHOT:
/* Core internal bug */
if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
return -ENOSYS;
- return dev->set_state_oneshot(dev);
+ if (dev->set_state_oneshot)
+ return dev->set_state_oneshot(dev);
+ return 0;

case CLOCK_EVT_STATE_ONESHOT_STOPPED:
/* Core internal bug */
@@ -471,18 +477,6 @@ static int clockevents_sanity_check(struct clock_event_device *dev)
if (dev->features & CLOCK_EVT_FEAT_DUMMY)
return 0;

- /* New state-specific callbacks */
- if (!dev->set_state_shutdown)
- return -EINVAL;
-
- if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
- !dev->set_state_periodic)
- return -EINVAL;
-
- if ((dev->features & CLOCK_EVT_FEAT_ONESHOT) &&
- !dev->set_state_oneshot)
- return -EINVAL;
-
return 0;
}

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index d39f32cdd1b5..52b9e199b5ac 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -159,7 +159,7 @@ 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;
+ int ret = 0;

raw_spin_lock_irqsave(&tick_broadcast_lock, flags);

@@ -221,13 +221,14 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
* 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.
+ * is delivered by the broadcast device, if
+ * the broadcast device exists and is not
+ * hrtimer based.
*/
- ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
+ if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER))
+ ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
break;
default:
- /* Nothing to do */
- ret = 0;
break;
}
}
@@ -265,8 +266,22 @@ static bool tick_do_broadcast(struct cpumask *mask)
* Check, if the current cpu is in the mask
*/
if (cpumask_test_cpu(cpu, mask)) {
+ struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
cpumask_clear_cpu(cpu, mask);
- local = true;
+ /*
+ * We only run the local handler, if the broadcast
+ * device is not hrtimer based. Otherwise we run into
+ * a hrtimer recursion.
+ *
+ * local timer_interrupt()
+ * local_handler()
+ * expire_hrtimers()
+ * bc_handler()
+ * local_handler()
+ * expire_hrtimers()
+ */
+ local = !(bc->features & CLOCK_EVT_FEAT_HRTIMER);
}

if (!cpumask_empty(mask)) {
@@ -301,6 +316,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
bool bc_local;

raw_spin_lock(&tick_broadcast_lock);
+
+ /* Handle spurious interrupts gracefully */
+ if (clockevent_state_shutdown(tick_broadcast_device.evtdev)) {
+ raw_spin_unlock(&tick_broadcast_lock);
+ return;
+ }
+
bc_local = tick_do_periodic_broadcast();

if (clockevent_state_oneshot(dev)) {
@@ -359,8 +381,16 @@ void tick_broadcast_control(enum tick_broadcast_mode mode)
case TICK_BROADCAST_ON:
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)
+ /*
+ * Only shutdown the cpu local device, if:
+ *
+ * - the broadcast device exists
+ * - the broadcast device is not a hrtimer based one
+ * - the broadcast device is in periodic mode to
+ * avoid a hickup during switch to oneshot mode
+ */
+ if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER) &&
+ tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
clockevents_shutdown(dev);
}
break;
@@ -379,14 +409,16 @@ void tick_broadcast_control(enum tick_broadcast_mode mode)
break;
}

- if (cpumask_empty(tick_broadcast_mask)) {
- if (!bc_stopped)
- clockevents_shutdown(bc);
- } else if (bc_stopped) {
- if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
- tick_broadcast_start_periodic(bc);
- else
- tick_broadcast_setup_oneshot(bc);
+ if (bc) {
+ if (cpumask_empty(tick_broadcast_mask)) {
+ if (!bc_stopped)
+ clockevents_shutdown(bc);
+ } else if (bc_stopped) {
+ if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+ tick_broadcast_start_periodic(bc);
+ else
+ tick_broadcast_setup_oneshot(bc);
+ }
}
raw_spin_unlock(&tick_broadcast_lock);
}
@@ -662,71 +694,82 @@ static void broadcast_shutdown_local(struct clock_event_device *bc,
clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN);
}

-/**
- * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode
- * @state: The target state (enter/exit)
- *
- * The system enters/leaves a state, where affected devices might stop
- * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups.
- *
- * Called with interrupts disabled, so clockevents_lock is not
- * required here because the local clock event device cannot go away
- * under us.
- */
-int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
{
struct clock_event_device *bc, *dev;
- struct tick_device *td;
int cpu, ret = 0;
ktime_t now;

/*
- * Periodic mode does not care about the enter/exit of power
- * states
+ * If there is no broadcast device, tell the caller not to go
+ * into deep idle.
*/
- if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
- return 0;
+ if (!tick_broadcast_device.evtdev)
+ return -EBUSY;

- /*
- * We are called with preemtion disabled from the depth of the
- * idle code, so we can't be moved away.
- */
- td = this_cpu_ptr(&tick_cpu_device);
- dev = td->evtdev;
-
- if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
- return 0;
+ dev = this_cpu_ptr(&tick_cpu_device)->evtdev;

raw_spin_lock(&tick_broadcast_lock);
bc = tick_broadcast_device.evtdev;
cpu = smp_processor_id();

if (state == TICK_BROADCAST_ENTER) {
+ /*
+ * If the current CPU owns the hrtimer broadcast
+ * mechanism, it cannot go deep idle and we do not add
+ * the CPU to 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)
+ goto out;
+
+ /*
+ * If the broadcast device is in periodic mode, we
+ * return.
+ */
+ if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
+ /* If it is a hrtimer based broadcast, return busy */
+ if (bc->features & CLOCK_EVT_FEAT_HRTIMER)
+ ret = -EBUSY;
+ goto out;
+ }
+
if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) {
WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
+
+ /* Conditionally shut down the local timer. */
broadcast_shutdown_local(bc, dev);
+
/*
* We only reprogram the broadcast timer if we
* did not mark ourself in the force mask and
* if the cpu local event is earlier than the
* broadcast event. If the current CPU is in
* the force mask, then we are going to be
- * woken by the IPI right away.
+ * woken by the IPI right away; we return
+ * busy, so the CPU does not try to go deep
+ * idle.
*/
- if (!cpumask_test_cpu(cpu, tick_broadcast_force_mask) &&
- dev->next_event.tv64 < bc->next_event.tv64)
+ if (cpumask_test_cpu(cpu, tick_broadcast_force_mask)) {
+ ret = -EBUSY;
+ } else if (dev->next_event.tv64 < bc->next_event.tv64) {
tick_broadcast_set_event(bc, cpu, dev->next_event);
+ /*
+ * In case of hrtimer broadcasts the
+ * programming might have moved the
+ * timer to this cpu. If yes, remove
+ * us from the broadcast mask and
+ * return busy.
+ */
+ ret = broadcast_needs_cpu(bc, cpu);
+ if (ret) {
+ cpumask_clear_cpu(cpu,
+ tick_broadcast_oneshot_mask);
+ }
+ }
}
- /*
- * 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_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
@@ -938,6 +981,16 @@ bool tick_broadcast_oneshot_available(void)
return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false;
}

+#else
+int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+ struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
+ if (!bc || (bc->features & CLOCK_EVT_FEAT_HRTIMER))
+ return -EBUSY;
+
+ return 0;
+}
#endif

void __init tick_broadcast_init(void)
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 76446cb5dfe1..55e13efff1ab 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -343,6 +343,27 @@ out_bc:
tick_install_broadcast_device(newdev);
}

+/**
+ * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode
+ * @state: The target state (enter/exit)
+ *
+ * The system enters/leaves a state, where affected devices might stop
+ * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups.
+ *
+ * Called with interrupts disabled, so clockevents_lock is not
+ * required here because the local clock event device cannot go away
+ * under us.
+ */
+int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+ struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+
+ if (!(td->evtdev->features & CLOCK_EVT_FEAT_C3STOP))
+ return 0;
+
+ return __tick_broadcast_oneshot_control(state);
+}
+
#ifdef CONFIG_HOTPLUG_CPU
/*
* Transfer the do_timer job away from a dying cpu.
diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h
index 42fdf4958bcc..a4a8d4e9baa1 100644
--- a/kernel/time/tick-sched.h
+++ b/kernel/time/tick-sched.h
@@ -71,4 +71,14 @@ extern void tick_cancel_sched_timer(int cpu);
static inline void tick_cancel_sched_timer(int cpu) { }
#endif

+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+extern int __tick_broadcast_oneshot_control(enum tick_broadcast_state state);
+#else
+static inline int
+__tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+ return -EBUSY;
+}
+#endif
+
#endif
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