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[ARM] 3554/1: ARM: Fix dyntick locking

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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>
This commit is contained in:
Tony Lindgren
2006-06-18 16:26:58 +01:00
committed by Russell King
parent 36fe6a83b4
commit ebc67da65f
3 changed files with 20 additions and 9 deletions
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4
arch/arm/kernel/irq.c
View File

@@ -342,10 +342,10 @@ __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
#ifdef CONFIG_NO_IDLE_HZ #ifdef CONFIG_NO_IDLE_HZ
if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) { if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) {
write_seqlock(&xtime_lock); spin_lock(&system_timer->dyn_tick->lock);
if (system_timer->dyn_tick->state & DYN_TICK_ENABLED) if (system_timer->dyn_tick->state & DYN_TICK_ENABLED)
system_timer->dyn_tick->handler(irq, 0, regs); system_timer->dyn_tick->handler(irq, 0, regs);
write_sequnlock(&xtime_lock); spin_unlock(&system_timer->dyn_tick->lock);
} }
#endif #endif

24
arch/arm/kernel/time.c
View File

@@ -379,7 +379,7 @@ static int timer_dyn_tick_enable(void)
int ret = -ENODEV; int ret = -ENODEV;
if (dyn_tick) { if (dyn_tick) {
write_seqlock_irqsave(&xtime_lock, flags); spin_lock_irqsave(&dyn_tick->lock, flags);
ret = 0; ret = 0;
if (!(dyn_tick->state & DYN_TICK_ENABLED)) { if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
ret = dyn_tick->enable(); ret = dyn_tick->enable();
@@ -387,7 +387,7 @@ static int timer_dyn_tick_enable(void)
if (ret == 0) if (ret == 0)
dyn_tick->state |= DYN_TICK_ENABLED; dyn_tick->state |= DYN_TICK_ENABLED;
} }
write_sequnlock_irqrestore(&xtime_lock, flags); spin_unlock_irqrestore(&dyn_tick->lock, flags);
} }
return ret; return ret;
@@ -400,7 +400,7 @@ static int timer_dyn_tick_disable(void)
int ret = -ENODEV; int ret = -ENODEV;
if (dyn_tick) { if (dyn_tick) {
write_seqlock_irqsave(&xtime_lock, flags); spin_lock_irqsave(&dyn_tick->lock, flags);
ret = 0; ret = 0;
if (dyn_tick->state & DYN_TICK_ENABLED) { if (dyn_tick->state & DYN_TICK_ENABLED) {
ret = dyn_tick->disable(); ret = dyn_tick->disable();
@@ -408,7 +408,7 @@ static int timer_dyn_tick_disable(void)
if (ret == 0) if (ret == 0)
dyn_tick->state &= ~DYN_TICK_ENABLED; dyn_tick->state &= ~DYN_TICK_ENABLED;
} }
write_sequnlock_irqrestore(&xtime_lock, flags); spin_unlock_irqrestore(&dyn_tick->lock, flags);
} }
return ret; return ret;
@@ -422,15 +422,20 @@ static int timer_dyn_tick_disable(void)
void timer_dyn_reprogram(void) void timer_dyn_reprogram(void)
{ {
struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 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(); next = next_timer_interrupt();
do { do {
seq = read_seqbegin(&xtime_lock); seq = read_seqbegin(&xtime_lock);
dyn_tick->reprogram(next_timer_interrupt() - jiffies); dyn_tick->reprogram(next - jiffies);
} while (read_seqretry(&xtime_lock, seq)); } 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) static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
@@ -499,5 +504,10 @@ void __init time_init(void)
if (system_timer->offset == NULL) if (system_timer->offset == NULL)
system_timer->offset = dummy_gettimeoffset; system_timer->offset = dummy_gettimeoffset;
system_timer->init(); system_timer->init();
#ifdef CONFIG_NO_IDLE_HZ
if (system_timer->dyn_tick)
system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
#endif
} }

1
include/asm-arm/mach/time.h
View File

@@ -50,6 +50,7 @@ struct sys_timer {
#define DYN_TICK_ENABLED (1 << 1) #define DYN_TICK_ENABLED (1 << 1)
struct dyn_tick_timer { struct dyn_tick_timer {
spinlock_t lock;
unsigned int state; /* Current state */ unsigned int state; /* Current state */
int (*enable)(void); /* Enables dynamic tick */ int (*enable)(void); /* Enables dynamic tick */
int (*disable)(void); /* Disables dynamic tick */ int (*disable)(void); /* Disables dynamic tick */