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authorJindong Yue <jindong.yue@nxp.com>2021-03-31 16:33:18 +0800
committerThomas Gleixner <tglx@linutronix.de>2021-04-16 21:03:50 +0200
commit9c336c9935cff267470bb3aaa85c66fac194b650 (patch)
treebab94e9be90d594b1743c5bd98a89eed3f6cdf86 /kernel/time/tick-broadcast.c
parentd7840aaadd6e84915866a8f0dab586f6107dadf1 (diff)
downloadlinux-9c336c9935cff267470bb3aaa85c66fac194b650.tar.gz
tick/broadcast: Allow late registered device to enter oneshot mode
The broadcast device is switched to oneshot mode when the system switches
to oneshot mode. If a broadcast clock event device is registered after the
system switched to oneshot mode, it will stay in periodic mode forever.

Ensure that a late registered device which is selected as broadcast device
is initialized in oneshot mode when the system already uses oneshot mode.

[ tglx: Massage changelog ]

Signed-off-by: Jindong Yue <jindong.yue@nxp.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210331083318.21794-1-jindong.yue@nxp.com

Diffstat (limited to 'kernel/time/tick-broadcast.c')
-rw-r--r--kernel/time/tick-broadcast.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 6ec7855ab88d..a44055228796 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -107,6 +107,19 @@ void tick_install_broadcast_device(struct clock_event_device *dev)
 	tick_broadcast_device.evtdev = dev;
 	if (!cpumask_empty(tick_broadcast_mask))
 		tick_broadcast_start_periodic(dev);
+
+	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
+		return;
+
+	/*
+	 * If the system already runs in oneshot mode, switch the newly
+	 * registered broadcast device to oneshot mode explicitly.
+	 */
+	if (tick_broadcast_oneshot_active()) {
+		tick_broadcast_switch_to_oneshot();
+		return;
+	}
+
 	/*
 	 * Inform all cpus about this. We might be in a situation
 	 * where we did not switch to oneshot mode because the per cpu
@@ -115,8 +128,7 @@ void tick_install_broadcast_device(struct clock_event_device *dev)
 	 * notification the systems stays stuck in periodic mode
 	 * forever.
 	 */
-	if (dev->features & CLOCK_EVT_FEAT_ONESHOT)
-		tick_clock_notify();
+	tick_clock_notify();
 }
 
 /*