2 * linux/kernel/irq/spurious.c
4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
6 * This file contains spurious interrupt handling.
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>
17 #include "internals.h"
19 static int irqfixup __read_mostly;
21 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
22 static void poll_spurious_irqs(unsigned long dummy);
23 static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
24 static int irq_poll_cpu;
25 static atomic_t irq_poll_active;
28 * We wait here for a poller to finish.
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.
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.
38 bool irq_wait_for_poll(struct irq_desc *desc)
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))
47 raw_spin_unlock(&desc->lock);
48 while (irqd_irq_inprogress(&desc->irq_data))
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;
61 * Recovery handler for misrouted interrupts.
63 static int try_one_irq(int irq, struct irq_desc *desc, bool force)
65 irqreturn_t ret = IRQ_NONE;
66 struct irqaction *action;
68 raw_spin_lock(&desc->lock);
71 * PER_CPU, nested thread interrupts and interrupts explicitely
72 * marked polled are excluded from polling.
74 if (irq_settings_is_per_cpu(desc) ||
75 irq_settings_is_nested_thread(desc) ||
76 irq_settings_is_polled(desc))
80 * Do not poll disabled interrupts unless the spurious
81 * disabled poller asks explicitely.
83 if (irqd_irq_disabled(&desc->irq_data) && !force)
87 * All handlers must agree on IRQF_SHARED, so we test just the
90 action = desc->action;
91 if (!action || !(action->flags & IRQF_SHARED) ||
92 (action->flags & __IRQF_TIMER))
95 /* Already running on another processor */
96 if (irqd_irq_inprogress(&desc->irq_data)) {
98 * Already running: If it is shared get the other
99 * CPU to go looking for our mystery interrupt too
101 desc->istate |= IRQS_PENDING;
105 /* Mark it poll in progress */
106 desc->istate |= IRQS_POLL_INPROGRESS;
108 if (handle_irq_event(desc) == IRQ_HANDLED)
110 /* Make sure that there is still a valid action */
111 action = desc->action;
112 } while ((desc->istate & IRQS_PENDING) && action);
113 desc->istate &= ~IRQS_POLL_INPROGRESS;
115 raw_spin_unlock(&desc->lock);
116 return ret == IRQ_HANDLED;
119 static int misrouted_irq(int irq)
121 struct irq_desc *desc;
124 if (atomic_inc_return(&irq_poll_active) != 1)
127 irq_poll_cpu = smp_processor_id();
129 for_each_irq_desc(i, desc) {
133 if (i == irq) /* Already tried */
136 if (try_one_irq(i, desc, false))
140 atomic_dec(&irq_poll_active);
141 /* So the caller can adjust the irq error counts */
145 static void poll_spurious_irqs(unsigned long dummy)
147 struct irq_desc *desc;
150 if (atomic_inc_return(&irq_poll_active) != 1)
152 irq_poll_cpu = smp_processor_id();
154 for_each_irq_desc(i, desc) {
160 /* Racy but it doesn't matter */
161 state = desc->istate;
163 if (!(state & IRQS_SPURIOUS_DISABLED))
167 try_one_irq(i, desc, true);
171 atomic_dec(&irq_poll_active);
172 mod_timer(&poll_spurious_irq_timer,
173 jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
176 static inline int bad_action_ret(irqreturn_t action_ret)
178 if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
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.
188 * (The other 100-of-100,000 interrupts may have been a correctly
189 * functioning device sharing an IRQ with the failing one)
192 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
193 irqreturn_t action_ret)
195 struct irqaction *action;
198 if (bad_action_ret(action_ret)) {
199 printk(KERN_ERR "irq event %d: bogus return value %x\n",
202 printk(KERN_ERR "irq %d: nobody cared (try booting with "
203 "the \"irqpoll\" option)\n", irq);
206 printk(KERN_ERR "handlers:\n");
209 * We need to take desc->lock here. note_interrupt() is called
210 * w/o desc->lock held, but IRQ_PROGRESS set. We might race
211 * with something else removing an action. It's ok to take
212 * desc->lock here. See synchronize_irq().
214 raw_spin_lock_irqsave(&desc->lock, flags);
215 action = desc->action;
217 printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
218 if (action->thread_fn)
219 printk(KERN_CONT " threaded [<%p>] %pf",
220 action->thread_fn, action->thread_fn);
221 printk(KERN_CONT "\n");
222 action = action->next;
224 raw_spin_unlock_irqrestore(&desc->lock, flags);
228 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
230 static int count = 100;
234 __report_bad_irq(irq, desc, action_ret);
239 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
240 irqreturn_t action_ret)
242 struct irqaction *action;
247 /* We didn't actually handle the IRQ - see if it was misrouted? */
248 if (action_ret == IRQ_NONE)
252 * But for 'irqfixup == 2' we also do it for handled interrupts if
253 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
254 * traditional PC timer interrupt.. Legacy)
263 * Since we don't get the descriptor lock, "action" can
264 * change under us. We don't really care, but we don't
265 * want to follow a NULL pointer. So tell the compiler to
266 * just load it once by using a barrier.
268 action = desc->action;
270 return action && (action->flags & IRQF_IRQPOLL);
273 void note_interrupt(unsigned int irq, struct irq_desc *desc,
274 irqreturn_t action_ret)
276 if (desc->istate & IRQS_POLL_INPROGRESS ||
277 irq_settings_is_polled(desc))
280 /* we get here again via the threaded handler */
281 if (action_ret == IRQ_WAKE_THREAD)
284 if (bad_action_ret(action_ret)) {
285 report_bad_irq(irq, desc, action_ret);
289 if (unlikely(action_ret == IRQ_NONE)) {
291 * If we are seeing only the odd spurious IRQ caused by
292 * bus asynchronicity then don't eventually trigger an error,
293 * otherwise the counter becomes a doomsday timer for otherwise
296 if (time_after(jiffies, desc->last_unhandled + HZ/10))
297 desc->irqs_unhandled = 1;
299 desc->irqs_unhandled++;
300 desc->last_unhandled = jiffies;
303 if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
304 int ok = misrouted_irq(irq);
305 if (action_ret == IRQ_NONE)
306 desc->irqs_unhandled -= ok;
310 if (likely(desc->irq_count < 100000))
314 if (unlikely(desc->irqs_unhandled > 99900)) {
316 * The interrupt is stuck
318 __report_bad_irq(irq, desc, action_ret);
322 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
323 desc->istate |= IRQS_SPURIOUS_DISABLED;
327 mod_timer(&poll_spurious_irq_timer,
328 jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
330 desc->irqs_unhandled = 0;
333 bool noirqdebug __read_mostly;
335 int noirqdebug_setup(char *str)
338 printk(KERN_INFO "IRQ lockup detection disabled\n");
343 __setup("noirqdebug", noirqdebug_setup);
344 module_param(noirqdebug, bool, 0644);
345 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
347 static int __init irqfixup_setup(char *str)
350 printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
351 printk(KERN_WARNING "This may impact system performance.\n");
356 __setup("irqfixup", irqfixup_setup);
357 module_param(irqfixup, int, 0644);
359 static int __init irqpoll_setup(char *str)
362 printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
364 printk(KERN_WARNING "This may significantly impact system "
369 __setup("irqpoll", irqpoll_setup);