[ARM] 3554/1: ARM: Fix dyntick locking
Patch from Tony Lindgren
This patch fixes some dyntick locking issues on ARM as pointed
out by Russell King.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
index d6bd435..9c12d4f 100644
--- a/arch/arm/kernel/time.c
+++ b/arch/arm/kernel/time.c
@@ -379,7 +379,7 @@
int ret = -ENODEV;
if (dyn_tick) {
- write_seqlock_irqsave(&xtime_lock, flags);
+ spin_lock_irqsave(&dyn_tick->lock, flags);
ret = 0;
if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
ret = dyn_tick->enable();
@@ -387,7 +387,7 @@
if (ret == 0)
dyn_tick->state |= DYN_TICK_ENABLED;
}
- write_sequnlock_irqrestore(&xtime_lock, flags);
+ spin_unlock_irqrestore(&dyn_tick->lock, flags);
}
return ret;
@@ -400,7 +400,7 @@
int ret = -ENODEV;
if (dyn_tick) {
- write_seqlock_irqsave(&xtime_lock, flags);
+ spin_lock_irqsave(&dyn_tick->lock, flags);
ret = 0;
if (dyn_tick->state & DYN_TICK_ENABLED) {
ret = dyn_tick->disable();
@@ -408,7 +408,7 @@
if (ret == 0)
dyn_tick->state &= ~DYN_TICK_ENABLED;
}
- write_sequnlock_irqrestore(&xtime_lock, flags);
+ spin_unlock_irqrestore(&dyn_tick->lock, flags);
}
return ret;
@@ -422,15 +422,20 @@
void timer_dyn_reprogram(void)
{
struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
- unsigned long next, seq;
+ unsigned long next, seq, flags;
- if (dyn_tick && (dyn_tick->state & DYN_TICK_ENABLED)) {
+ if (!dyn_tick)
+ return;
+
+ spin_lock_irqsave(&dyn_tick->lock, flags);
+ if (dyn_tick->state & DYN_TICK_ENABLED) {
next = next_timer_interrupt();
do {
seq = read_seqbegin(&xtime_lock);
- dyn_tick->reprogram(next_timer_interrupt() - jiffies);
+ dyn_tick->reprogram(next - jiffies);
} while (read_seqretry(&xtime_lock, seq));
}
+ spin_unlock_irqrestore(&dyn_tick->lock, flags);
}
static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
@@ -499,5 +504,10 @@
if (system_timer->offset == NULL)
system_timer->offset = dummy_gettimeoffset;
system_timer->init();
+
+#ifdef CONFIG_NO_IDLE_HZ
+ if (system_timer->dyn_tick)
+ system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
+#endif
}