[mirror_ubuntu-zesty-kernel.git] / kernel / irq / spurious.c

/*
 * 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>

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);

/*
 * Recovery handler for misrouted interrupts.
 */
static int try_one_irq(int irq, struct irq_desc *desc)
{
	struct irqaction *action;
	int ok = 0, work = 0;

	spin_lock(&desc->lock);
	/* Already running on another processor */
	if (desc->status & IRQ_INPROGRESS) {
		/*
		 * Already running: If it is shared get the other
		 * CPU to go looking for our mystery interrupt too
		 */
		if (desc->action && (desc->action->flags & IRQF_SHARED))
			desc->status |= IRQ_PENDING;
		spin_unlock(&desc->lock);
		return ok;
	}
	/* Honour the normal IRQ locking */
	desc->status |= IRQ_INPROGRESS;
	action = desc->action;
	spin_unlock(&desc->lock);

	while (action) {
		/* Only shared IRQ handlers are safe to call */
		if (action->flags & IRQF_SHARED) {
			if (action->handler(irq, action->dev_id) ==
				IRQ_HANDLED)
				ok = 1;
		}
		action = action->next;
	}
	local_irq_disable();
	/* Now clean up the flags */
	spin_lock(&desc->lock);
	action = desc->action;

	/*
	 * While we were looking for a fixup someone queued a real
	 * IRQ clashing with our walk:
	 */
	while ((desc->status & IRQ_PENDING) && action) {
		/*
		 * Perform real IRQ processing for the IRQ we deferred
		 */
		work = 1;
		spin_unlock(&desc->lock);
		handle_IRQ_event(irq, action);
		spin_lock(&desc->lock);
		desc->status &= ~IRQ_PENDING;
	}
	desc->status &= ~IRQ_INPROGRESS;
	/*
	 * If we did actual work for the real IRQ line we must let the
	 * IRQ controller clean up too
	 */
	if (work && desc->chip && desc->chip->end)
		desc->chip->end(irq);
	spin_unlock(&desc->lock);

	return ok;
}

static int misrouted_irq(int irq)
{
	struct irq_desc *desc;
	int i, ok = 0;

	for_each_irq_desc(i, desc) {
		if (!i)
			 continue;

		if (i == irq)	/* Already tried */
			continue;

		if (try_one_irq(i, desc))
			ok = 1;
	}
	/* So the caller can adjust the irq error counts */
	return ok;
}

static void poll_all_shared_irqs(void)
{
	struct irq_desc *desc;
	int i;

	for_each_irq_desc(i, desc) {
		unsigned int status;

		if (!i)
			 continue;

		/* Racy but it doesn't matter */
		status = desc->status;
		barrier();
		if (!(status & IRQ_SPURIOUS_DISABLED))
			continue;

		try_one_irq(i, desc);
	}
}

static void poll_spurious_irqs(unsigned long dummy)
{
	poll_all_shared_irqs();

	mod_timer(&poll_spurious_irq_timer,
		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
}

#ifdef CONFIG_DEBUG_SHIRQ
void debug_poll_all_shared_irqs(void)
{
	poll_all_shared_irqs();
}
#endif

/*
 * 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)
 *
 * Called under desc->lock
 */

static void
__report_bad_irq(unsigned int irq, struct irq_desc *desc,
		 irqreturn_t action_ret)
{
	struct irqaction *action;

	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
		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");

	action = desc->action;
	while (action) {
		printk(KERN_ERR "[<%p>]", action->handler);
		print_symbol(" (%s)",
			(unsigned long)action->handler);
		printk("\n");
		action = action->next;
	}
}

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 (unlikely(action_ret != IRQ_HANDLED)) {
		/*
		 * If we are seeing only the odd spurious IRQ caused by
		 * bus asynchronicity then don't eventually trigger an error,
		 * otherwise the couter 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(action_ret != IRQ_NONE))
			report_bad_irq(irq, desc, action_ret);
	}

	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->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
		desc->depth++;
		desc->chip->disable(irq);

		mod_timer(&poll_spurious_irq_timer,
			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
	}
	desc->irqs_unhandled = 0;
}

int 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);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/irq/spurious.c
	3	*
	4	* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
	5	*
	6	* This file contains spurious interrupt handling.
	7	*/
	8
188fd89d	9	#include <linux/jiffies.h>
1da177e4 LT	10	#include <linux/irq.h>
	11	#include <linux/module.h>
	12	#include <linux/kallsyms.h>
	13	#include <linux/interrupt.h>
9e094c17	14	#include <linux/moduleparam.h>
f84dbb91	15	#include <linux/timer.h>
1da177e4	16
83d4e6e7	17	static int irqfixup __read_mostly;
200803df	18
f84dbb91 EB	19	#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
	20	static void poll_spurious_irqs(unsigned long dummy);
	21	static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
	22
200803df AC	23	/*
	24	* Recovery handler for misrouted interrupts.
	25	*/
f84dbb91	26	static int try_one_irq(int irq, struct irq_desc *desc)
200803df	27	{
f84dbb91	28	struct irqaction *action;
d3c60047	29	int ok = 0, work = 0;
200803df	30
f84dbb91 EB	31	spin_lock(&desc->lock);
	32	/* Already running on another processor */
	33	if (desc->status & IRQ_INPROGRESS) {
	34	/*
	35	* Already running: If it is shared get the other
	36	* CPU to go looking for our mystery interrupt too
	37	*/
	38	if (desc->action && (desc->action->flags & IRQF_SHARED))
	39	desc->status \|= IRQ_PENDING;
200803df	40	spin_unlock(&desc->lock);
f84dbb91 EB	41	return ok;
	42	}
	43	/* Honour the normal IRQ locking */
	44	desc->status \|= IRQ_INPROGRESS;
	45	action = desc->action;
	46	spin_unlock(&desc->lock);
06fcb0c6	47
f84dbb91 EB	48	while (action) {
	49	/* Only shared IRQ handlers are safe to call */
	50	if (action->flags & IRQF_SHARED) {
	51	if (action->handler(irq, action->dev_id) ==
	52	IRQ_HANDLED)
	53	ok = 1;
200803df	54	}
f84dbb91 EB	55	action = action->next;
	56	}
	57	local_irq_disable();
	58	/* Now clean up the flags */
	59	spin_lock(&desc->lock);
	60	action = desc->action;
200803df	61
f84dbb91 EB	62	/*
	63	* While we were looking for a fixup someone queued a real
	64	* IRQ clashing with our walk:
	65	*/
	66	while ((desc->status & IRQ_PENDING) && action) {
200803df	67	/*
f84dbb91	68	* Perform real IRQ processing for the IRQ we deferred
200803df	69	*/
f84dbb91	70	work = 1;
200803df	71	spin_unlock(&desc->lock);
f84dbb91 EB	72	handle_IRQ_event(irq, action);
	73	spin_lock(&desc->lock);
	74	desc->status &= ~IRQ_PENDING;
	75	}
	76	desc->status &= ~IRQ_INPROGRESS;
	77	/*
	78	* If we did actual work for the real IRQ line we must let the
	79	* IRQ controller clean up too
	80	*/
	81	if (work && desc->chip && desc->chip->end)
	82	desc->chip->end(irq);
	83	spin_unlock(&desc->lock);
	84
	85	return ok;
	86	}
	87
	88	static int misrouted_irq(int irq)
	89	{
e00585bb	90	struct irq_desc *desc;
d3c60047	91	int i, ok = 0;
f84dbb91	92
e00585bb YL	93	for_each_irq_desc(i, desc) {
	94	if (!i)
	95	continue;
f84dbb91 EB	96
	97	if (i == irq) /* Already tried */
	98	continue;
	99
	100	if (try_one_irq(i, desc))
	101	ok = 1;
200803df AC	102	}
	103	/* So the caller can adjust the irq error counts */
	104	return ok;
	105	}
	106
74296a8e	107	static void poll_all_shared_irqs(void)
f84dbb91	108	{
e00585bb	109	struct irq_desc *desc;
d3c60047	110	int i;
e00585bb YL	111
e00585bb YL	112	for_each_irq_desc(i, desc) {
f84dbb91 EB	113	unsigned int status;
f84dbb91 EB	114
e00585bb YL	115	if (!i)
	116	continue;
	117
f84dbb91 EB	118	/* Racy but it doesn't matter */
	119	status = desc->status;
	120	barrier();
	121	if (!(status & IRQ_SPURIOUS_DISABLED))
	122	continue;
	123
	124	try_one_irq(i, desc);
	125	}
74296a8e IM	126	}
	127
	128	static void poll_spurious_irqs(unsigned long dummy)
	129	{
	130	poll_all_shared_irqs();
f84dbb91	131
d3c60047 TG	132	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	133	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
f84dbb91 EB	134	}
f84dbb91 EB	135
74296a8e IM	136	#ifdef CONFIG_DEBUG_SHIRQ
	137	void debug_poll_all_shared_irqs(void)
	138	{
	139	poll_all_shared_irqs();
	140	}
	141	#endif
	142
1da177e4 LT	143	/*
	144	* If 99,900 of the previous 100,000 interrupts have not been handled
	145	* then assume that the IRQ is stuck in some manner. Drop a diagnostic
	146	* and try to turn the IRQ off.
	147	*
	148	* (The other 100-of-100,000 interrupts may have been a correctly
	149	* functioning device sharing an IRQ with the failing one)
	150	*
	151	* Called under desc->lock
	152	*/
	153
	154	static void
34ffdb72 IM	155	__report_bad_irq(unsigned int irq, struct irq_desc *desc,
34ffdb72 IM	156	irqreturn_t action_ret)
1da177e4 LT	157	{
	158	struct irqaction *action;
	159
	160	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
	161	printk(KERN_ERR "irq event %d: bogus return value %x\n",
	162	irq, action_ret);
	163	} else {
200803df AC	164	printk(KERN_ERR "irq %d: nobody cared (try booting with "
200803df AC	165	"the \"irqpoll\" option)\n", irq);
1da177e4 LT	166	}
	167	dump_stack();
	168	printk(KERN_ERR "handlers:\n");
06fcb0c6	169
1da177e4 LT	170	action = desc->action;
	171	while (action) {
	172	printk(KERN_ERR "[<%p>]", action->handler);
	173	print_symbol(" (%s)",
	174	(unsigned long)action->handler);
	175	printk("\n");
	176	action = action->next;
	177	}
	178	}
	179
06fcb0c6	180	static void
34ffdb72	181	report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
1da177e4 LT	182	{
	183	static int count = 100;
	184
	185	if (count > 0) {
	186	count--;
	187	__report_bad_irq(irq, desc, action_ret);
	188	}
	189	}
	190
d3c60047 TG	191	static inline int
	192	try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
	193	irqreturn_t action_ret)
92ea7727 LT	194	{
	195	struct irqaction *action;
	196
	197	if (!irqfixup)
	198	return 0;
	199
	200	/* We didn't actually handle the IRQ - see if it was misrouted? */
	201	if (action_ret == IRQ_NONE)
	202	return 1;
	203
	204	/*
	205	* But for 'irqfixup == 2' we also do it for handled interrupts if
	206	* they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	207	* traditional PC timer interrupt.. Legacy)
	208	*/
	209	if (irqfixup < 2)
	210	return 0;
	211
	212	if (!irq)
	213	return 1;
	214
	215	/*
	216	* Since we don't get the descriptor lock, "action" can
	217	* change under us. We don't really care, but we don't
	218	* want to follow a NULL pointer. So tell the compiler to
	219	* just load it once by using a barrier.
	220	*/
	221	action = desc->action;
	222	barrier();
	223	return action && (action->flags & IRQF_IRQPOLL);
	224	}
	225
34ffdb72	226	void note_interrupt(unsigned int irq, struct irq_desc *desc,
7d12e780	227	irqreturn_t action_ret)
1da177e4	228	{
83d4e6e7	229	if (unlikely(action_ret != IRQ_HANDLED)) {
4f27c00b AC	230	/*
	231	* If we are seeing only the odd spurious IRQ caused by
	232	* bus asynchronicity then don't eventually trigger an error,
	233	* otherwise the couter becomes a doomsday timer for otherwise
	234	* working systems
	235	*/
188fd89d	236	if (time_after(jiffies, desc->last_unhandled + HZ/10))
4f27c00b AC	237	desc->irqs_unhandled = 1;
	238	else
	239	desc->irqs_unhandled++;
	240	desc->last_unhandled = jiffies;
83d4e6e7	241	if (unlikely(action_ret != IRQ_NONE))
1da177e4 LT	242	report_bad_irq(irq, desc, action_ret);
	243	}
	244
92ea7727 LT	245	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
	246	int ok = misrouted_irq(irq);
	247	if (action_ret == IRQ_NONE)
	248	desc->irqs_unhandled -= ok;
200803df AC	249	}
200803df AC	250
1da177e4	251	desc->irq_count++;
83d4e6e7	252	if (likely(desc->irq_count < 100000))
1da177e4 LT	253	return;
	254
	255	desc->irq_count = 0;
83d4e6e7	256	if (unlikely(desc->irqs_unhandled > 99900)) {
1da177e4 LT	257	/*
	258	* The interrupt is stuck
	259	*/
	260	__report_bad_irq(irq, desc, action_ret);
	261	/*
	262	* Now kill the IRQ
	263	*/
	264	printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
1adb0850 TG	265	desc->status \|= IRQ_DISABLED \| IRQ_SPURIOUS_DISABLED;
1adb0850 TG	266	desc->depth++;
d1bef4ed	267	desc->chip->disable(irq);
f84dbb91	268
d3c60047 TG	269	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	270	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
1da177e4 LT	271	}
	272	desc->irqs_unhandled = 0;
	273	}
	274
83d4e6e7	275	int noirqdebug __read_mostly;
1da177e4	276
343cde51	277	int noirqdebug_setup(char *str)
1da177e4 LT	278	{
	279	noirqdebug = 1;
	280	printk(KERN_INFO "IRQ lockup detection disabled\n");
06fcb0c6	281
1da177e4 LT	282	return 1;
	283	}
	284
	285	__setup("noirqdebug", noirqdebug_setup);
9e094c17 AK	286	module_param(noirqdebug, bool, 0644);
9e094c17 AK	287	MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
1da177e4	288
200803df AC	289	static int __init irqfixup_setup(char *str)
	290	{
	291	irqfixup = 1;
	292	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	293	printk(KERN_WARNING "This may impact system performance.\n");
06fcb0c6	294
200803df AC	295	return 1;
	296	}
	297
	298	__setup("irqfixup", irqfixup_setup);
9e094c17	299	module_param(irqfixup, int, 0644);
200803df AC	300
	301	static int __init irqpoll_setup(char *str)
	302	{
	303	irqfixup = 2;
	304	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
	305	"enabled\n");
	306	printk(KERN_WARNING "This may significantly impact system "
	307	"performance\n");
	308	return 1;
	309	}
	310
	311	__setup("irqpoll", irqpoll_setup);