1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5 * This file contains spurious interrupt handling.
8 #include <linux/jiffies.h>
10 #include <linux/module.h>
11 #include <linux/interrupt.h>
12 #include <linux/moduleparam.h>
13 #include <linux/timer.h>
15 #include "internals.h"
17 static int irqfixup __read_mostly;
19 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
20 static void poll_spurious_irqs(struct timer_list *unused);
21 static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs);
22 static int irq_poll_cpu;
23 static atomic_t irq_poll_active;
26 * We wait here for a poller to finish.
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.
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.
36 bool irq_wait_for_poll(struct irq_desc *desc)
37 __must_hold(&desc->lock)
39 if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
40 "irq poll in progress on cpu %d for irq %d\n",
41 smp_processor_id(), desc->irq_data.irq))
46 raw_spin_unlock(&desc->lock);
47 while (irqd_irq_inprogress(&desc->irq_data))
49 raw_spin_lock(&desc->lock);
50 } while (irqd_irq_inprogress(&desc->irq_data));
51 /* Might have been disabled in meantime */
52 return !irqd_irq_disabled(&desc->irq_data) && desc->action;
60 * Recovery handler for misrouted interrupts.
62 static int try_one_irq(struct irq_desc *desc, bool force)
64 irqreturn_t ret = IRQ_NONE;
65 struct irqaction *action;
67 raw_spin_lock(&desc->lock);
70 * PER_CPU, nested thread interrupts and interrupts explicitly
71 * marked polled are excluded from polling.
73 if (irq_settings_is_per_cpu(desc) ||
74 irq_settings_is_nested_thread(desc) ||
75 irq_settings_is_polled(desc))
79 * Do not poll disabled interrupts unless the spurious
80 * disabled poller asks explicitly.
82 if (irqd_irq_disabled(&desc->irq_data) && !force)
86 * All handlers must agree on IRQF_SHARED, so we test just the
89 action = desc->action;
90 if (!action || !(action->flags & IRQF_SHARED) ||
91 (action->flags & __IRQF_TIMER))
94 /* Already running on another processor */
95 if (irqd_irq_inprogress(&desc->irq_data)) {
97 * Already running: If it is shared get the other
98 * CPU to go looking for our mystery interrupt too
100 desc->istate |= IRQS_PENDING;
104 /* Mark it poll in progress */
105 desc->istate |= IRQS_POLL_INPROGRESS;
107 if (handle_irq_event(desc) == IRQ_HANDLED)
109 /* Make sure that there is still a valid action */
110 action = desc->action;
111 } while ((desc->istate & IRQS_PENDING) && action);
112 desc->istate &= ~IRQS_POLL_INPROGRESS;
114 raw_spin_unlock(&desc->lock);
115 return ret == IRQ_HANDLED;
118 static int misrouted_irq(int irq)
120 struct irq_desc *desc;
123 if (atomic_inc_return(&irq_poll_active) != 1)
126 irq_poll_cpu = smp_processor_id();
128 for_each_irq_desc(i, desc) {
132 if (i == irq) /* Already tried */
135 if (try_one_irq(desc, false))
139 atomic_dec(&irq_poll_active);
140 /* So the caller can adjust the irq error counts */
144 static void poll_spurious_irqs(struct timer_list *unused)
146 struct irq_desc *desc;
149 if (atomic_inc_return(&irq_poll_active) != 1)
151 irq_poll_cpu = smp_processor_id();
153 for_each_irq_desc(i, desc) {
159 /* Racy but it doesn't matter */
160 state = desc->istate;
162 if (!(state & IRQS_SPURIOUS_DISABLED))
166 try_one_irq(desc, true);
170 atomic_dec(&irq_poll_active);
171 mod_timer(&poll_spurious_irq_timer,
172 jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
175 static inline int bad_action_ret(irqreturn_t action_ret)
177 unsigned int r = action_ret;
179 if (likely(r <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
185 * If 99,900 of the previous 100,000 interrupts have not been handled
186 * then assume that the IRQ is stuck in some manner. Drop a diagnostic
187 * and try to turn the IRQ off.
189 * (The other 100-of-100,000 interrupts may have been a correctly
190 * functioning device sharing an IRQ with the failing one)
192 static void __report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
194 unsigned int irq = irq_desc_get_irq(desc);
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 for_each_action_of_desc(desc, action) {
216 printk(KERN_ERR "[<%p>] %ps", action->handler, action->handler);
217 if (action->thread_fn)
218 printk(KERN_CONT " threaded [<%p>] %ps",
219 action->thread_fn, action->thread_fn);
220 printk(KERN_CONT "\n");
222 raw_spin_unlock_irqrestore(&desc->lock, flags);
225 static void report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
227 static int count = 100;
231 __report_bad_irq(desc, action_ret);
236 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
237 irqreturn_t action_ret)
239 struct irqaction *action;
244 /* We didn't actually handle the IRQ - see if it was misrouted? */
245 if (action_ret == IRQ_NONE)
249 * But for 'irqfixup == 2' we also do it for handled interrupts if
250 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
251 * traditional PC timer interrupt.. Legacy)
260 * Since we don't get the descriptor lock, "action" can
261 * change under us. We don't really care, but we don't
262 * want to follow a NULL pointer. So tell the compiler to
263 * just load it once by using a barrier.
265 action = desc->action;
267 return action && (action->flags & IRQF_IRQPOLL);
270 #define SPURIOUS_DEFERRED 0x80000000
272 void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
276 if (desc->istate & IRQS_POLL_INPROGRESS ||
277 irq_settings_is_polled(desc))
280 if (bad_action_ret(action_ret)) {
281 report_bad_irq(desc, action_ret);
286 * We cannot call note_interrupt from the threaded handler
287 * because we need to look at the compound of all handlers
288 * (primary and threaded). Aside of that in the threaded
289 * shared case we have no serialization against an incoming
290 * hardware interrupt while we are dealing with a threaded
293 * So in case a thread is woken, we just note the fact and
294 * defer the analysis to the next hardware interrupt.
296 * The threaded handlers store whether they successfully
297 * handled an interrupt and we check whether that number
298 * changed versus the last invocation.
300 * We could handle all interrupts with the delayed by one
301 * mechanism, but for the non forced threaded case we'd just
302 * add pointless overhead to the straight hardirq interrupts
303 * for the sake of a few lines less code.
305 if (action_ret & IRQ_WAKE_THREAD) {
307 * There is a thread woken. Check whether one of the
308 * shared primary handlers returned IRQ_HANDLED. If
309 * not we defer the spurious detection to the next
312 if (action_ret == IRQ_WAKE_THREAD) {
315 * We use bit 31 of thread_handled_last to
316 * denote the deferred spurious detection
317 * active. No locking necessary as
318 * thread_handled_last is only accessed here
319 * and we have the guarantee that hard
320 * interrupts are not reentrant.
322 if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) {
323 desc->threads_handled_last |= SPURIOUS_DEFERRED;
327 * Check whether one of the threaded handlers
328 * returned IRQ_HANDLED since the last
329 * interrupt happened.
331 * For simplicity we just set bit 31, as it is
332 * set in threads_handled_last as well. So we
333 * avoid extra masking. And we really do not
334 * care about the high bits of the handled
335 * count. We just care about the count being
336 * different than the one we saw before.
338 handled = atomic_read(&desc->threads_handled);
339 handled |= SPURIOUS_DEFERRED;
340 if (handled != desc->threads_handled_last) {
341 action_ret = IRQ_HANDLED;
343 * Note: We keep the SPURIOUS_DEFERRED
344 * bit set. We are handling the
345 * previous invocation right now.
346 * Keep it for the current one, so the
347 * next hardware interrupt will
350 desc->threads_handled_last = handled;
353 * None of the threaded handlers felt
354 * responsible for the last interrupt
356 * We keep the SPURIOUS_DEFERRED bit
357 * set in threads_handled_last as we
358 * need to account for the current
361 action_ret = IRQ_NONE;
365 * One of the primary handlers returned
366 * IRQ_HANDLED. So we don't care about the
367 * threaded handlers on the same line. Clear
368 * the deferred detection bit.
370 * In theory we could/should check whether the
371 * deferred bit is set and take the result of
372 * the previous run into account here as
373 * well. But it's really not worth the
374 * trouble. If every other interrupt is
375 * handled we never trigger the spurious
376 * detector. And if this is just the one out
377 * of 100k unhandled ones which is handled
378 * then we merily delay the spurious detection
379 * by one hard interrupt. Not a real problem.
381 desc->threads_handled_last &= ~SPURIOUS_DEFERRED;
385 if (unlikely(action_ret == IRQ_NONE)) {
387 * If we are seeing only the odd spurious IRQ caused by
388 * bus asynchronicity then don't eventually trigger an error,
389 * otherwise the counter becomes a doomsday timer for otherwise
392 if (time_after(jiffies, desc->last_unhandled + HZ/10))
393 desc->irqs_unhandled = 1;
395 desc->irqs_unhandled++;
396 desc->last_unhandled = jiffies;
399 irq = irq_desc_get_irq(desc);
400 if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
401 int ok = misrouted_irq(irq);
402 if (action_ret == IRQ_NONE)
403 desc->irqs_unhandled -= ok;
407 if (likely(desc->irq_count < 100000))
411 if (unlikely(desc->irqs_unhandled > 99900)) {
413 * The interrupt is stuck
415 __report_bad_irq(desc, action_ret);
419 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
420 desc->istate |= IRQS_SPURIOUS_DISABLED;
424 mod_timer(&poll_spurious_irq_timer,
425 jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
427 desc->irqs_unhandled = 0;
430 bool noirqdebug __read_mostly;
432 int noirqdebug_setup(char *str)
435 printk(KERN_INFO "IRQ lockup detection disabled\n");
440 __setup("noirqdebug", noirqdebug_setup);
441 module_param(noirqdebug, bool, 0644);
442 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
444 static int __init irqfixup_setup(char *str)
446 #ifdef CONFIG_PREEMPT_RT
447 pr_warn("irqfixup boot option not supported w/ CONFIG_PREEMPT_RT\n");
451 printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
452 printk(KERN_WARNING "This may impact system performance.\n");
457 __setup("irqfixup", irqfixup_setup);
458 module_param(irqfixup, int, 0644);
460 static int __init irqpoll_setup(char *str)
462 #ifdef CONFIG_PREEMPT_RT
463 pr_warn("irqpoll boot option not supported w/ CONFIG_PREEMPT_RT\n");
467 printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
469 printk(KERN_WARNING "This may significantly impact system "
474 __setup("irqpoll", irqpoll_setup);