| /* | 
 |  * linux/kernel/irq/spurious.c | 
 |  * | 
 |  * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar | 
 |  * | 
 |  * This file contains spurious interrupt handling. | 
 |  */ | 
 |  | 
 | #include <linux/jiffies.h> | 
 | #include <linux/irq.h> | 
 | #include <linux/module.h> | 
 | #include <linux/kallsyms.h> | 
 | #include <linux/interrupt.h> | 
 | #include <linux/moduleparam.h> | 
 | #include <linux/timer.h> | 
 |  | 
 | #include "internals.h" | 
 |  | 
 | static int irqfixup __read_mostly; | 
 |  | 
 | #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10) | 
 | static void poll_spurious_irqs(unsigned long dummy); | 
 | static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0); | 
 | static int irq_poll_cpu; | 
 | static atomic_t irq_poll_active; | 
 |  | 
 | /* | 
 |  * We wait here for a poller to finish. | 
 |  * | 
 |  * If the poll runs on this CPU, then we yell loudly and return | 
 |  * false. That will leave the interrupt line disabled in the worst | 
 |  * case, but it should never happen. | 
 |  * | 
 |  * We wait until the poller is done and then recheck disabled and | 
 |  * action (about to be disabled). Only if it's still active, we return | 
 |  * true and let the handler run. | 
 |  */ | 
 | bool irq_wait_for_poll(struct irq_desc *desc) | 
 | { | 
 | 	if (WARN_ONCE(irq_poll_cpu == smp_processor_id(), | 
 | 		      "irq poll in progress on cpu %d for irq %d\n", | 
 | 		      smp_processor_id(), desc->irq_data.irq)) | 
 | 		return false; | 
 |  | 
 | #ifdef CONFIG_SMP | 
 | 	do { | 
 | 		raw_spin_unlock(&desc->lock); | 
 | 		while (irqd_irq_inprogress(&desc->irq_data)) | 
 | 			cpu_relax(); | 
 | 		raw_spin_lock(&desc->lock); | 
 | 	} while (irqd_irq_inprogress(&desc->irq_data)); | 
 | 	/* Might have been disabled in meantime */ | 
 | 	return !irqd_irq_disabled(&desc->irq_data) && desc->action; | 
 | #else | 
 | 	return false; | 
 | #endif | 
 | } | 
 |  | 
 |  | 
 | /* | 
 |  * Recovery handler for misrouted interrupts. | 
 |  */ | 
 | static int try_one_irq(int irq, struct irq_desc *desc, bool force) | 
 | { | 
 | 	irqreturn_t ret = IRQ_NONE; | 
 | 	struct irqaction *action; | 
 |  | 
 | 	raw_spin_lock(&desc->lock); | 
 |  | 
 | 	/* PER_CPU and nested thread interrupts are never polled */ | 
 | 	if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc)) | 
 | 		goto out; | 
 |  | 
 | 	/* | 
 | 	 * Do not poll disabled interrupts unless the spurious | 
 | 	 * disabled poller asks explicitely. | 
 | 	 */ | 
 | 	if (irqd_irq_disabled(&desc->irq_data) && !force) | 
 | 		goto out; | 
 |  | 
 | 	/* | 
 | 	 * All handlers must agree on IRQF_SHARED, so we test just the | 
 | 	 * first. Check for action->next as well. | 
 | 	 */ | 
 | 	action = desc->action; | 
 | 	if (!action || !(action->flags & IRQF_SHARED) || | 
 | 	    (action->flags & __IRQF_TIMER) || | 
 | 	    (action->handler(irq, action->dev_id) == IRQ_HANDLED) || | 
 | 	    !action->next) | 
 | 		goto out; | 
 |  | 
 | 	/* Already running on another processor */ | 
 | 	if (irqd_irq_inprogress(&desc->irq_data)) { | 
 | 		/* | 
 | 		 * Already running: If it is shared get the other | 
 | 		 * CPU to go looking for our mystery interrupt too | 
 | 		 */ | 
 | 		desc->istate |= IRQS_PENDING; | 
 | 		goto out; | 
 | 	} | 
 |  | 
 | 	/* Mark it poll in progress */ | 
 | 	desc->istate |= IRQS_POLL_INPROGRESS; | 
 | 	do { | 
 | 		if (handle_irq_event(desc) == IRQ_HANDLED) | 
 | 			ret = IRQ_HANDLED; | 
 | 		action = desc->action; | 
 | 	} while ((desc->istate & IRQS_PENDING) && action); | 
 | 	desc->istate &= ~IRQS_POLL_INPROGRESS; | 
 | out: | 
 | 	raw_spin_unlock(&desc->lock); | 
 | 	return ret == IRQ_HANDLED; | 
 | } | 
 |  | 
 | static int misrouted_irq(int irq) | 
 | { | 
 | 	struct irq_desc *desc; | 
 | 	int i, ok = 0; | 
 |  | 
 | 	if (atomic_inc_return(&irq_poll_active) != 1) | 
 | 		goto out; | 
 |  | 
 | 	irq_poll_cpu = smp_processor_id(); | 
 |  | 
 | 	for_each_irq_desc(i, desc) { | 
 | 		if (!i) | 
 | 			 continue; | 
 |  | 
 | 		if (i == irq)	/* Already tried */ | 
 | 			continue; | 
 |  | 
 | 		if (try_one_irq(i, desc, false)) | 
 | 			ok = 1; | 
 | 	} | 
 | out: | 
 | 	atomic_dec(&irq_poll_active); | 
 | 	/* So the caller can adjust the irq error counts */ | 
 | 	return ok; | 
 | } | 
 |  | 
 | static void poll_spurious_irqs(unsigned long dummy) | 
 | { | 
 | 	struct irq_desc *desc; | 
 | 	int i; | 
 |  | 
 | 	if (atomic_inc_return(&irq_poll_active) != 1) | 
 | 		goto out; | 
 | 	irq_poll_cpu = smp_processor_id(); | 
 |  | 
 | 	for_each_irq_desc(i, desc) { | 
 | 		unsigned int state; | 
 |  | 
 | 		if (!i) | 
 | 			 continue; | 
 |  | 
 | 		/* Racy but it doesn't matter */ | 
 | 		state = desc->istate; | 
 | 		barrier(); | 
 | 		if (!(state & IRQS_SPURIOUS_DISABLED)) | 
 | 			continue; | 
 |  | 
 | 		local_irq_disable(); | 
 | 		try_one_irq(i, desc, true); | 
 | 		local_irq_enable(); | 
 | 	} | 
 | out: | 
 | 	atomic_dec(&irq_poll_active); | 
 | 	mod_timer(&poll_spurious_irq_timer, | 
 | 		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL); | 
 | } | 
 |  | 
 | static inline int bad_action_ret(irqreturn_t action_ret) | 
 | { | 
 | 	if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD))) | 
 | 		return 0; | 
 | 	return 1; | 
 | } | 
 |  | 
 | /* | 
 |  * If 99,900 of the previous 100,000 interrupts have not been handled | 
 |  * then assume that the IRQ is stuck in some manner. Drop a diagnostic | 
 |  * and try to turn the IRQ off. | 
 |  * | 
 |  * (The other 100-of-100,000 interrupts may have been a correctly | 
 |  *  functioning device sharing an IRQ with the failing one) | 
 |  */ | 
 | static void | 
 | __report_bad_irq(unsigned int irq, struct irq_desc *desc, | 
 | 		 irqreturn_t action_ret) | 
 | { | 
 | 	struct irqaction *action; | 
 | 	unsigned long flags; | 
 |  | 
 | 	if (bad_action_ret(action_ret)) { | 
 | 		printk(KERN_ERR "irq event %d: bogus return value %x\n", | 
 | 				irq, action_ret); | 
 | 	} else { | 
 | 		printk(KERN_ERR "irq %d: nobody cared (try booting with " | 
 | 				"the \"irqpoll\" option)\n", irq); | 
 | 	} | 
 | 	dump_stack(); | 
 | 	printk(KERN_ERR "handlers:\n"); | 
 |  | 
 | 	/* | 
 | 	 * We need to take desc->lock here. note_interrupt() is called | 
 | 	 * w/o desc->lock held, but IRQ_PROGRESS set. We might race | 
 | 	 * with something else removing an action. It's ok to take | 
 | 	 * desc->lock here. See synchronize_irq(). | 
 | 	 */ | 
 | 	raw_spin_lock_irqsave(&desc->lock, flags); | 
 | 	action = desc->action; | 
 | 	while (action) { | 
 | 		printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler); | 
 | 		if (action->thread_fn) | 
 | 			printk(KERN_CONT " threaded [<%p>] %pf", | 
 | 					action->thread_fn, action->thread_fn); | 
 | 		printk(KERN_CONT "\n"); | 
 | 		action = action->next; | 
 | 	} | 
 | 	raw_spin_unlock_irqrestore(&desc->lock, flags); | 
 | } | 
 |  | 
 | static void | 
 | report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret) | 
 | { | 
 | 	static int count = 100; | 
 |  | 
 | 	if (count > 0) { | 
 | 		count--; | 
 | 		__report_bad_irq(irq, desc, action_ret); | 
 | 	} | 
 | } | 
 |  | 
 | static inline int | 
 | try_misrouted_irq(unsigned int irq, struct irq_desc *desc, | 
 | 		  irqreturn_t action_ret) | 
 | { | 
 | 	struct irqaction *action; | 
 |  | 
 | 	if (!irqfixup) | 
 | 		return 0; | 
 |  | 
 | 	/* We didn't actually handle the IRQ - see if it was misrouted? */ | 
 | 	if (action_ret == IRQ_NONE) | 
 | 		return 1; | 
 |  | 
 | 	/* | 
 | 	 * But for 'irqfixup == 2' we also do it for handled interrupts if | 
 | 	 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the | 
 | 	 * traditional PC timer interrupt.. Legacy) | 
 | 	 */ | 
 | 	if (irqfixup < 2) | 
 | 		return 0; | 
 |  | 
 | 	if (!irq) | 
 | 		return 1; | 
 |  | 
 | 	/* | 
 | 	 * Since we don't get the descriptor lock, "action" can | 
 | 	 * change under us.  We don't really care, but we don't | 
 | 	 * want to follow a NULL pointer. So tell the compiler to | 
 | 	 * just load it once by using a barrier. | 
 | 	 */ | 
 | 	action = desc->action; | 
 | 	barrier(); | 
 | 	return action && (action->flags & IRQF_IRQPOLL); | 
 | } | 
 |  | 
 | void note_interrupt(unsigned int irq, struct irq_desc *desc, | 
 | 		    irqreturn_t action_ret) | 
 | { | 
 | 	if (desc->istate & IRQS_POLL_INPROGRESS) | 
 | 		return; | 
 |  | 
 | 	/* we get here again via the threaded handler */ | 
 | 	if (action_ret == IRQ_WAKE_THREAD) | 
 | 		return; | 
 |  | 
 | 	if (bad_action_ret(action_ret)) { | 
 | 		report_bad_irq(irq, desc, action_ret); | 
 | 		return; | 
 | 	} | 
 |  | 
 | 	if (unlikely(action_ret == IRQ_NONE)) { | 
 | 		/* | 
 | 		 * If we are seeing only the odd spurious IRQ caused by | 
 | 		 * bus asynchronicity then don't eventually trigger an error, | 
 | 		 * otherwise the counter becomes a doomsday timer for otherwise | 
 | 		 * working systems | 
 | 		 */ | 
 | 		if (time_after(jiffies, desc->last_unhandled + HZ/10)) | 
 | 			desc->irqs_unhandled = 1; | 
 | 		else | 
 | 			desc->irqs_unhandled++; | 
 | 		desc->last_unhandled = jiffies; | 
 | 	} | 
 |  | 
 | 	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) { | 
 | 		int ok = misrouted_irq(irq); | 
 | 		if (action_ret == IRQ_NONE) | 
 | 			desc->irqs_unhandled -= ok; | 
 | 	} | 
 |  | 
 | 	desc->irq_count++; | 
 | 	if (likely(desc->irq_count < 100000)) | 
 | 		return; | 
 |  | 
 | 	desc->irq_count = 0; | 
 | 	if (unlikely(desc->irqs_unhandled > 99900)) { | 
 | 		/* | 
 | 		 * The interrupt is stuck | 
 | 		 */ | 
 | 		__report_bad_irq(irq, desc, action_ret); | 
 | 		/* | 
 | 		 * Now kill the IRQ | 
 | 		 */ | 
 | 		printk(KERN_EMERG "Disabling IRQ #%d\n", irq); | 
 | 		desc->istate |= IRQS_SPURIOUS_DISABLED; | 
 | 		desc->depth++; | 
 | 		irq_disable(desc); | 
 |  | 
 | 		mod_timer(&poll_spurious_irq_timer, | 
 | 			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL); | 
 | 	} | 
 | 	desc->irqs_unhandled = 0; | 
 | } | 
 |  | 
 | bool noirqdebug __read_mostly; | 
 |  | 
 | int noirqdebug_setup(char *str) | 
 | { | 
 | 	noirqdebug = 1; | 
 | 	printk(KERN_INFO "IRQ lockup detection disabled\n"); | 
 |  | 
 | 	return 1; | 
 | } | 
 |  | 
 | __setup("noirqdebug", noirqdebug_setup); | 
 | module_param(noirqdebug, bool, 0644); | 
 | MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true"); | 
 |  | 
 | static int __init irqfixup_setup(char *str) | 
 | { | 
 | 	irqfixup = 1; | 
 | 	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n"); | 
 | 	printk(KERN_WARNING "This may impact system performance.\n"); | 
 |  | 
 | 	return 1; | 
 | } | 
 |  | 
 | __setup("irqfixup", irqfixup_setup); | 
 | module_param(irqfixup, int, 0644); | 
 |  | 
 | static int __init irqpoll_setup(char *str) | 
 | { | 
 | 	irqfixup = 2; | 
 | 	printk(KERN_WARNING "Misrouted IRQ fixup and polling support " | 
 | 				"enabled\n"); | 
 | 	printk(KERN_WARNING "This may significantly impact system " | 
 | 				"performance\n"); | 
 | 	return 1; | 
 | } | 
 |  | 
 | __setup("irqpoll", irqpoll_setup); |