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v5.4
  1// SPDX-License-Identifier: GPL-2.0
  2/*
 
 
  3 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
  4 *
  5 * This file contains spurious interrupt handling.
  6 */
  7
  8#include <linux/jiffies.h>
  9#include <linux/irq.h>
 10#include <linux/module.h>
 
 11#include <linux/interrupt.h>
 12#include <linux/moduleparam.h>
 13#include <linux/timer.h>
 14
 15#include "internals.h"
 16
 17static int irqfixup __read_mostly;
 18
 19#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
 20static void poll_spurious_irqs(struct timer_list *unused);
 21static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs);
 22static int irq_poll_cpu;
 23static atomic_t irq_poll_active;
 24
 25/*
 26 * We wait here for a poller to finish.
 27 *
 28 * If the poll runs on this CPU, then we yell loudly and return
 29 * false. That will leave the interrupt line disabled in the worst
 30 * case, but it should never happen.
 31 *
 32 * We wait until the poller is done and then recheck disabled and
 33 * action (about to be disabled). Only if it's still active, we return
 34 * true and let the handler run.
 35 */
 36bool irq_wait_for_poll(struct irq_desc *desc)
 37{
 38	if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
 39		      "irq poll in progress on cpu %d for irq %d\n",
 40		      smp_processor_id(), desc->irq_data.irq))
 41		return false;
 42
 43#ifdef CONFIG_SMP
 44	do {
 45		raw_spin_unlock(&desc->lock);
 46		while (irqd_irq_inprogress(&desc->irq_data))
 47			cpu_relax();
 48		raw_spin_lock(&desc->lock);
 49	} while (irqd_irq_inprogress(&desc->irq_data));
 50	/* Might have been disabled in meantime */
 51	return !irqd_irq_disabled(&desc->irq_data) && desc->action;
 52#else
 53	return false;
 54#endif
 55}
 56
 57
 58/*
 59 * Recovery handler for misrouted interrupts.
 60 */
 61static int try_one_irq(struct irq_desc *desc, bool force)
 62{
 63	irqreturn_t ret = IRQ_NONE;
 64	struct irqaction *action;
 65
 66	raw_spin_lock(&desc->lock);
 67
 68	/*
 69	 * PER_CPU, nested thread interrupts and interrupts explicitly
 70	 * marked polled are excluded from polling.
 71	 */
 72	if (irq_settings_is_per_cpu(desc) ||
 73	    irq_settings_is_nested_thread(desc) ||
 74	    irq_settings_is_polled(desc))
 75		goto out;
 76
 77	/*
 78	 * Do not poll disabled interrupts unless the spurious
 79	 * disabled poller asks explicitly.
 80	 */
 81	if (irqd_irq_disabled(&desc->irq_data) && !force)
 82		goto out;
 83
 84	/*
 85	 * All handlers must agree on IRQF_SHARED, so we test just the
 86	 * first.
 87	 */
 88	action = desc->action;
 89	if (!action || !(action->flags & IRQF_SHARED) ||
 90	    (action->flags & __IRQF_TIMER))
 91		goto out;
 92
 93	/* Already running on another processor */
 94	if (irqd_irq_inprogress(&desc->irq_data)) {
 95		/*
 96		 * Already running: If it is shared get the other
 97		 * CPU to go looking for our mystery interrupt too
 98		 */
 99		desc->istate |= IRQS_PENDING;
100		goto out;
101	}
102
103	/* Mark it poll in progress */
104	desc->istate |= IRQS_POLL_INPROGRESS;
105	do {
106		if (handle_irq_event(desc) == IRQ_HANDLED)
107			ret = IRQ_HANDLED;
108		/* Make sure that there is still a valid action */
109		action = desc->action;
110	} while ((desc->istate & IRQS_PENDING) && action);
111	desc->istate &= ~IRQS_POLL_INPROGRESS;
112out:
113	raw_spin_unlock(&desc->lock);
114	return ret == IRQ_HANDLED;
115}
116
117static int misrouted_irq(int irq)
118{
119	struct irq_desc *desc;
120	int i, ok = 0;
121
122	if (atomic_inc_return(&irq_poll_active) != 1)
123		goto out;
124
125	irq_poll_cpu = smp_processor_id();
126
127	for_each_irq_desc(i, desc) {
128		if (!i)
129			 continue;
130
131		if (i == irq)	/* Already tried */
132			continue;
133
134		if (try_one_irq(desc, false))
135			ok = 1;
136	}
137out:
138	atomic_dec(&irq_poll_active);
139	/* So the caller can adjust the irq error counts */
140	return ok;
141}
142
143static void poll_spurious_irqs(struct timer_list *unused)
144{
145	struct irq_desc *desc;
146	int i;
147
148	if (atomic_inc_return(&irq_poll_active) != 1)
149		goto out;
150	irq_poll_cpu = smp_processor_id();
151
152	for_each_irq_desc(i, desc) {
153		unsigned int state;
154
155		if (!i)
156			 continue;
157
158		/* Racy but it doesn't matter */
159		state = desc->istate;
160		barrier();
161		if (!(state & IRQS_SPURIOUS_DISABLED))
162			continue;
163
164		local_irq_disable();
165		try_one_irq(desc, true);
166		local_irq_enable();
167	}
168out:
169	atomic_dec(&irq_poll_active);
170	mod_timer(&poll_spurious_irq_timer,
171		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
172}
173
174static inline int bad_action_ret(irqreturn_t action_ret)
175{
176	unsigned int r = action_ret;
177
178	if (likely(r <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
179		return 0;
180	return 1;
181}
182
183/*
184 * If 99,900 of the previous 100,000 interrupts have not been handled
185 * then assume that the IRQ is stuck in some manner. Drop a diagnostic
186 * and try to turn the IRQ off.
187 *
188 * (The other 100-of-100,000 interrupts may have been a correctly
189 *  functioning device sharing an IRQ with the failing one)
190 */
191static void __report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
 
 
192{
193	unsigned int irq = irq_desc_get_irq(desc);
194	struct irqaction *action;
195	unsigned long flags;
196
197	if (bad_action_ret(action_ret)) {
198		printk(KERN_ERR "irq event %d: bogus return value %x\n",
199				irq, action_ret);
200	} else {
201		printk(KERN_ERR "irq %d: nobody cared (try booting with "
202				"the \"irqpoll\" option)\n", irq);
203	}
204	dump_stack();
205	printk(KERN_ERR "handlers:\n");
206
207	/*
208	 * We need to take desc->lock here. note_interrupt() is called
209	 * w/o desc->lock held, but IRQ_PROGRESS set. We might race
210	 * with something else removing an action. It's ok to take
211	 * desc->lock here. See synchronize_irq().
212	 */
213	raw_spin_lock_irqsave(&desc->lock, flags);
214	for_each_action_of_desc(desc, action) {
215		printk(KERN_ERR "[<%p>] %ps", action->handler, action->handler);
 
216		if (action->thread_fn)
217			printk(KERN_CONT " threaded [<%p>] %ps",
218					action->thread_fn, action->thread_fn);
219		printk(KERN_CONT "\n");
 
220	}
221	raw_spin_unlock_irqrestore(&desc->lock, flags);
222}
223
224static void report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
 
225{
226	static int count = 100;
227
228	if (count > 0) {
229		count--;
230		__report_bad_irq(desc, action_ret);
231	}
232}
233
234static inline int
235try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
236		  irqreturn_t action_ret)
237{
238	struct irqaction *action;
239
240	if (!irqfixup)
241		return 0;
242
243	/* We didn't actually handle the IRQ - see if it was misrouted? */
244	if (action_ret == IRQ_NONE)
245		return 1;
246
247	/*
248	 * But for 'irqfixup == 2' we also do it for handled interrupts if
249	 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
250	 * traditional PC timer interrupt.. Legacy)
251	 */
252	if (irqfixup < 2)
253		return 0;
254
255	if (!irq)
256		return 1;
257
258	/*
259	 * Since we don't get the descriptor lock, "action" can
260	 * change under us.  We don't really care, but we don't
261	 * want to follow a NULL pointer. So tell the compiler to
262	 * just load it once by using a barrier.
263	 */
264	action = desc->action;
265	barrier();
266	return action && (action->flags & IRQF_IRQPOLL);
267}
268
269#define SPURIOUS_DEFERRED	0x80000000
270
271void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
272{
273	unsigned int irq;
 
274
275	if (desc->istate & IRQS_POLL_INPROGRESS ||
276	    irq_settings_is_polled(desc))
277		return;
278
279	if (bad_action_ret(action_ret)) {
280		report_bad_irq(desc, action_ret);
281		return;
282	}
283
284	/*
285	 * We cannot call note_interrupt from the threaded handler
286	 * because we need to look at the compound of all handlers
287	 * (primary and threaded). Aside of that in the threaded
288	 * shared case we have no serialization against an incoming
289	 * hardware interrupt while we are dealing with a threaded
290	 * result.
291	 *
292	 * So in case a thread is woken, we just note the fact and
293	 * defer the analysis to the next hardware interrupt.
294	 *
295	 * The threaded handlers store whether they successfully
296	 * handled an interrupt and we check whether that number
297	 * changed versus the last invocation.
298	 *
299	 * We could handle all interrupts with the delayed by one
300	 * mechanism, but for the non forced threaded case we'd just
301	 * add pointless overhead to the straight hardirq interrupts
302	 * for the sake of a few lines less code.
303	 */
304	if (action_ret & IRQ_WAKE_THREAD) {
305		/*
306		 * There is a thread woken. Check whether one of the
307		 * shared primary handlers returned IRQ_HANDLED. If
308		 * not we defer the spurious detection to the next
309		 * interrupt.
310		 */
311		if (action_ret == IRQ_WAKE_THREAD) {
312			int handled;
313			/*
314			 * We use bit 31 of thread_handled_last to
315			 * denote the deferred spurious detection
316			 * active. No locking necessary as
317			 * thread_handled_last is only accessed here
318			 * and we have the guarantee that hard
319			 * interrupts are not reentrant.
320			 */
321			if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) {
322				desc->threads_handled_last |= SPURIOUS_DEFERRED;
323				return;
324			}
325			/*
326			 * Check whether one of the threaded handlers
327			 * returned IRQ_HANDLED since the last
328			 * interrupt happened.
329			 *
330			 * For simplicity we just set bit 31, as it is
331			 * set in threads_handled_last as well. So we
332			 * avoid extra masking. And we really do not
333			 * care about the high bits of the handled
334			 * count. We just care about the count being
335			 * different than the one we saw before.
336			 */
337			handled = atomic_read(&desc->threads_handled);
338			handled |= SPURIOUS_DEFERRED;
339			if (handled != desc->threads_handled_last) {
340				action_ret = IRQ_HANDLED;
341				/*
342				 * Note: We keep the SPURIOUS_DEFERRED
343				 * bit set. We are handling the
344				 * previous invocation right now.
345				 * Keep it for the current one, so the
346				 * next hardware interrupt will
347				 * account for it.
348				 */
349				desc->threads_handled_last = handled;
350			} else {
351				/*
352				 * None of the threaded handlers felt
353				 * responsible for the last interrupt
354				 *
355				 * We keep the SPURIOUS_DEFERRED bit
356				 * set in threads_handled_last as we
357				 * need to account for the current
358				 * interrupt as well.
359				 */
360				action_ret = IRQ_NONE;
361			}
362		} else {
363			/*
364			 * One of the primary handlers returned
365			 * IRQ_HANDLED. So we don't care about the
366			 * threaded handlers on the same line. Clear
367			 * the deferred detection bit.
368			 *
369			 * In theory we could/should check whether the
370			 * deferred bit is set and take the result of
371			 * the previous run into account here as
372			 * well. But it's really not worth the
373			 * trouble. If every other interrupt is
374			 * handled we never trigger the spurious
375			 * detector. And if this is just the one out
376			 * of 100k unhandled ones which is handled
377			 * then we merily delay the spurious detection
378			 * by one hard interrupt. Not a real problem.
379			 */
380			desc->threads_handled_last &= ~SPURIOUS_DEFERRED;
381		}
382	}
383
384	if (unlikely(action_ret == IRQ_NONE)) {
385		/*
386		 * If we are seeing only the odd spurious IRQ caused by
387		 * bus asynchronicity then don't eventually trigger an error,
388		 * otherwise the counter becomes a doomsday timer for otherwise
389		 * working systems
390		 */
391		if (time_after(jiffies, desc->last_unhandled + HZ/10))
392			desc->irqs_unhandled = 1;
393		else
394			desc->irqs_unhandled++;
395		desc->last_unhandled = jiffies;
396	}
397
398	irq = irq_desc_get_irq(desc);
399	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
400		int ok = misrouted_irq(irq);
401		if (action_ret == IRQ_NONE)
402			desc->irqs_unhandled -= ok;
403	}
404
405	desc->irq_count++;
406	if (likely(desc->irq_count < 100000))
407		return;
408
409	desc->irq_count = 0;
410	if (unlikely(desc->irqs_unhandled > 99900)) {
411		/*
412		 * The interrupt is stuck
413		 */
414		__report_bad_irq(desc, action_ret);
415		/*
416		 * Now kill the IRQ
417		 */
418		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
419		desc->istate |= IRQS_SPURIOUS_DISABLED;
420		desc->depth++;
421		irq_disable(desc);
422
423		mod_timer(&poll_spurious_irq_timer,
424			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
425	}
426	desc->irqs_unhandled = 0;
427}
428
429bool noirqdebug __read_mostly;
430
431int noirqdebug_setup(char *str)
432{
433	noirqdebug = 1;
434	printk(KERN_INFO "IRQ lockup detection disabled\n");
435
436	return 1;
437}
438
439__setup("noirqdebug", noirqdebug_setup);
440module_param(noirqdebug, bool, 0644);
441MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
442
443static int __init irqfixup_setup(char *str)
444{
445	irqfixup = 1;
446	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
447	printk(KERN_WARNING "This may impact system performance.\n");
448
449	return 1;
450}
451
452__setup("irqfixup", irqfixup_setup);
453module_param(irqfixup, int, 0644);
454
455static int __init irqpoll_setup(char *str)
456{
457	irqfixup = 2;
458	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
459				"enabled\n");
460	printk(KERN_WARNING "This may significantly impact system "
461				"performance\n");
462	return 1;
463}
464
465__setup("irqpoll", irqpoll_setup);
v3.1
 
  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
  9#include <linux/jiffies.h>
 10#include <linux/irq.h>
 11#include <linux/module.h>
 12#include <linux/kallsyms.h>
 13#include <linux/interrupt.h>
 14#include <linux/moduleparam.h>
 15#include <linux/timer.h>
 16
 17#include "internals.h"
 18
 19static int irqfixup __read_mostly;
 20
 21#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
 22static void poll_spurious_irqs(unsigned long dummy);
 23static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
 24static int irq_poll_cpu;
 25static atomic_t irq_poll_active;
 26
 27/*
 28 * We wait here for a poller to finish.
 29 *
 30 * If the poll runs on this CPU, then we yell loudly and return
 31 * false. That will leave the interrupt line disabled in the worst
 32 * case, but it should never happen.
 33 *
 34 * We wait until the poller is done and then recheck disabled and
 35 * action (about to be disabled). Only if it's still active, we return
 36 * true and let the handler run.
 37 */
 38bool irq_wait_for_poll(struct irq_desc *desc)
 39{
 40	if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
 41		      "irq poll in progress on cpu %d for irq %d\n",
 42		      smp_processor_id(), desc->irq_data.irq))
 43		return false;
 44
 45#ifdef CONFIG_SMP
 46	do {
 47		raw_spin_unlock(&desc->lock);
 48		while (irqd_irq_inprogress(&desc->irq_data))
 49			cpu_relax();
 50		raw_spin_lock(&desc->lock);
 51	} while (irqd_irq_inprogress(&desc->irq_data));
 52	/* Might have been disabled in meantime */
 53	return !irqd_irq_disabled(&desc->irq_data) && desc->action;
 54#else
 55	return false;
 56#endif
 57}
 58
 59
 60/*
 61 * Recovery handler for misrouted interrupts.
 62 */
 63static int try_one_irq(int irq, struct irq_desc *desc, bool force)
 64{
 65	irqreturn_t ret = IRQ_NONE;
 66	struct irqaction *action;
 67
 68	raw_spin_lock(&desc->lock);
 69
 70	/* PER_CPU and nested thread interrupts are never polled */
 71	if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc))
 
 
 
 
 
 72		goto out;
 73
 74	/*
 75	 * Do not poll disabled interrupts unless the spurious
 76	 * disabled poller asks explicitely.
 77	 */
 78	if (irqd_irq_disabled(&desc->irq_data) && !force)
 79		goto out;
 80
 81	/*
 82	 * All handlers must agree on IRQF_SHARED, so we test just the
 83	 * first. Check for action->next as well.
 84	 */
 85	action = desc->action;
 86	if (!action || !(action->flags & IRQF_SHARED) ||
 87	    (action->flags & __IRQF_TIMER) || !action->next)
 88		goto out;
 89
 90	/* Already running on another processor */
 91	if (irqd_irq_inprogress(&desc->irq_data)) {
 92		/*
 93		 * Already running: If it is shared get the other
 94		 * CPU to go looking for our mystery interrupt too
 95		 */
 96		desc->istate |= IRQS_PENDING;
 97		goto out;
 98	}
 99
100	/* Mark it poll in progress */
101	desc->istate |= IRQS_POLL_INPROGRESS;
102	do {
103		if (handle_irq_event(desc) == IRQ_HANDLED)
104			ret = IRQ_HANDLED;
 
105		action = desc->action;
106	} while ((desc->istate & IRQS_PENDING) && action);
107	desc->istate &= ~IRQS_POLL_INPROGRESS;
108out:
109	raw_spin_unlock(&desc->lock);
110	return ret == IRQ_HANDLED;
111}
112
113static int misrouted_irq(int irq)
114{
115	struct irq_desc *desc;
116	int i, ok = 0;
117
118	if (atomic_inc_return(&irq_poll_active) == 1)
119		goto out;
120
121	irq_poll_cpu = smp_processor_id();
122
123	for_each_irq_desc(i, desc) {
124		if (!i)
125			 continue;
126
127		if (i == irq)	/* Already tried */
128			continue;
129
130		if (try_one_irq(i, desc, false))
131			ok = 1;
132	}
133out:
134	atomic_dec(&irq_poll_active);
135	/* So the caller can adjust the irq error counts */
136	return ok;
137}
138
139static void poll_spurious_irqs(unsigned long dummy)
140{
141	struct irq_desc *desc;
142	int i;
143
144	if (atomic_inc_return(&irq_poll_active) != 1)
145		goto out;
146	irq_poll_cpu = smp_processor_id();
147
148	for_each_irq_desc(i, desc) {
149		unsigned int state;
150
151		if (!i)
152			 continue;
153
154		/* Racy but it doesn't matter */
155		state = desc->istate;
156		barrier();
157		if (!(state & IRQS_SPURIOUS_DISABLED))
158			continue;
159
160		local_irq_disable();
161		try_one_irq(i, desc, true);
162		local_irq_enable();
163	}
164out:
165	atomic_dec(&irq_poll_active);
166	mod_timer(&poll_spurious_irq_timer,
167		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
168}
169
170static inline int bad_action_ret(irqreturn_t action_ret)
171{
172	if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
 
 
173		return 0;
174	return 1;
175}
176
177/*
178 * If 99,900 of the previous 100,000 interrupts have not been handled
179 * then assume that the IRQ is stuck in some manner. Drop a diagnostic
180 * and try to turn the IRQ off.
181 *
182 * (The other 100-of-100,000 interrupts may have been a correctly
183 *  functioning device sharing an IRQ with the failing one)
184 */
185static void
186__report_bad_irq(unsigned int irq, struct irq_desc *desc,
187		 irqreturn_t action_ret)
188{
 
189	struct irqaction *action;
190	unsigned long flags;
191
192	if (bad_action_ret(action_ret)) {
193		printk(KERN_ERR "irq event %d: bogus return value %x\n",
194				irq, action_ret);
195	} else {
196		printk(KERN_ERR "irq %d: nobody cared (try booting with "
197				"the \"irqpoll\" option)\n", irq);
198	}
199	dump_stack();
200	printk(KERN_ERR "handlers:\n");
201
202	/*
203	 * We need to take desc->lock here. note_interrupt() is called
204	 * w/o desc->lock held, but IRQ_PROGRESS set. We might race
205	 * with something else removing an action. It's ok to take
206	 * desc->lock here. See synchronize_irq().
207	 */
208	raw_spin_lock_irqsave(&desc->lock, flags);
209	action = desc->action;
210	while (action) {
211		printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
212		if (action->thread_fn)
213			printk(KERN_CONT " threaded [<%p>] %pf",
214					action->thread_fn, action->thread_fn);
215		printk(KERN_CONT "\n");
216		action = action->next;
217	}
218	raw_spin_unlock_irqrestore(&desc->lock, flags);
219}
220
221static void
222report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
223{
224	static int count = 100;
225
226	if (count > 0) {
227		count--;
228		__report_bad_irq(irq, desc, action_ret);
229	}
230}
231
232static inline int
233try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
234		  irqreturn_t action_ret)
235{
236	struct irqaction *action;
237
238	if (!irqfixup)
239		return 0;
240
241	/* We didn't actually handle the IRQ - see if it was misrouted? */
242	if (action_ret == IRQ_NONE)
243		return 1;
244
245	/*
246	 * But for 'irqfixup == 2' we also do it for handled interrupts if
247	 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
248	 * traditional PC timer interrupt.. Legacy)
249	 */
250	if (irqfixup < 2)
251		return 0;
252
253	if (!irq)
254		return 1;
255
256	/*
257	 * Since we don't get the descriptor lock, "action" can
258	 * change under us.  We don't really care, but we don't
259	 * want to follow a NULL pointer. So tell the compiler to
260	 * just load it once by using a barrier.
261	 */
262	action = desc->action;
263	barrier();
264	return action && (action->flags & IRQF_IRQPOLL);
265}
266
267void note_interrupt(unsigned int irq, struct irq_desc *desc,
268		    irqreturn_t action_ret)
 
269{
270	if (desc->istate & IRQS_POLL_INPROGRESS)
271		return;
272
273	/* we get here again via the threaded handler */
274	if (action_ret == IRQ_WAKE_THREAD)
275		return;
276
277	if (bad_action_ret(action_ret)) {
278		report_bad_irq(irq, desc, action_ret);
279		return;
280	}
281
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
282	if (unlikely(action_ret == IRQ_NONE)) {
283		/*
284		 * If we are seeing only the odd spurious IRQ caused by
285		 * bus asynchronicity then don't eventually trigger an error,
286		 * otherwise the counter becomes a doomsday timer for otherwise
287		 * working systems
288		 */
289		if (time_after(jiffies, desc->last_unhandled + HZ/10))
290			desc->irqs_unhandled = 1;
291		else
292			desc->irqs_unhandled++;
293		desc->last_unhandled = jiffies;
294	}
295
 
296	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
297		int ok = misrouted_irq(irq);
298		if (action_ret == IRQ_NONE)
299			desc->irqs_unhandled -= ok;
300	}
301
302	desc->irq_count++;
303	if (likely(desc->irq_count < 100000))
304		return;
305
306	desc->irq_count = 0;
307	if (unlikely(desc->irqs_unhandled > 99900)) {
308		/*
309		 * The interrupt is stuck
310		 */
311		__report_bad_irq(irq, desc, action_ret);
312		/*
313		 * Now kill the IRQ
314		 */
315		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
316		desc->istate |= IRQS_SPURIOUS_DISABLED;
317		desc->depth++;
318		irq_disable(desc);
319
320		mod_timer(&poll_spurious_irq_timer,
321			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
322	}
323	desc->irqs_unhandled = 0;
324}
325
326int noirqdebug __read_mostly;
327
328int noirqdebug_setup(char *str)
329{
330	noirqdebug = 1;
331	printk(KERN_INFO "IRQ lockup detection disabled\n");
332
333	return 1;
334}
335
336__setup("noirqdebug", noirqdebug_setup);
337module_param(noirqdebug, bool, 0644);
338MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
339
340static int __init irqfixup_setup(char *str)
341{
342	irqfixup = 1;
343	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
344	printk(KERN_WARNING "This may impact system performance.\n");
345
346	return 1;
347}
348
349__setup("irqfixup", irqfixup_setup);
350module_param(irqfixup, int, 0644);
351
352static int __init irqpoll_setup(char *str)
353{
354	irqfixup = 2;
355	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
356				"enabled\n");
357	printk(KERN_WARNING "This may significantly impact system "
358				"performance\n");
359	return 1;
360}
361
362__setup("irqpoll", irqpoll_setup);