Line data Source code
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 :
17 : static int irqfixup __read_mostly;
18 :
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;
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 : */
36 0 : bool irq_wait_for_poll(struct irq_desc *desc)
37 : __must_hold(&desc->lock)
38 : {
39 0 : 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))
42 : return false;
43 :
44 : #ifdef CONFIG_SMP
45 : do {
46 : raw_spin_unlock(&desc->lock);
47 : while (irqd_irq_inprogress(&desc->irq_data))
48 : cpu_relax();
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;
53 : #else
54 : return false;
55 : #endif
56 : }
57 :
58 :
59 : /*
60 : * Recovery handler for misrouted interrupts.
61 : */
62 0 : static int try_one_irq(struct irq_desc *desc, bool force)
63 : {
64 0 : irqreturn_t ret = IRQ_NONE;
65 : struct irqaction *action;
66 :
67 0 : raw_spin_lock(&desc->lock);
68 :
69 : /*
70 : * PER_CPU, nested thread interrupts and interrupts explicitly
71 : * marked polled are excluded from polling.
72 : */
73 0 : if (irq_settings_is_per_cpu(desc) ||
74 0 : irq_settings_is_nested_thread(desc) ||
75 0 : irq_settings_is_polled(desc))
76 : goto out;
77 :
78 : /*
79 : * Do not poll disabled interrupts unless the spurious
80 : * disabled poller asks explicitly.
81 : */
82 0 : if (irqd_irq_disabled(&desc->irq_data) && !force)
83 : goto out;
84 :
85 : /*
86 : * All handlers must agree on IRQF_SHARED, so we test just the
87 : * first.
88 : */
89 0 : action = desc->action;
90 0 : if (!action || !(action->flags & IRQF_SHARED) ||
91 : (action->flags & __IRQF_TIMER))
92 : goto out;
93 :
94 : /* Already running on another processor */
95 0 : if (irqd_irq_inprogress(&desc->irq_data)) {
96 : /*
97 : * Already running: If it is shared get the other
98 : * CPU to go looking for our mystery interrupt too
99 : */
100 0 : desc->istate |= IRQS_PENDING;
101 0 : goto out;
102 : }
103 :
104 : /* Mark it poll in progress */
105 0 : desc->istate |= IRQS_POLL_INPROGRESS;
106 : do {
107 0 : if (handle_irq_event(desc) == IRQ_HANDLED)
108 0 : ret = IRQ_HANDLED;
109 : /* Make sure that there is still a valid action */
110 0 : action = desc->action;
111 0 : } while ((desc->istate & IRQS_PENDING) && action);
112 0 : desc->istate &= ~IRQS_POLL_INPROGRESS;
113 : out:
114 0 : raw_spin_unlock(&desc->lock);
115 0 : return ret == IRQ_HANDLED;
116 : }
117 :
118 0 : static int misrouted_irq(int irq)
119 : {
120 : struct irq_desc *desc;
121 0 : int i, ok = 0;
122 :
123 0 : if (atomic_inc_return(&irq_poll_active) != 1)
124 : goto out;
125 :
126 0 : irq_poll_cpu = smp_processor_id();
127 :
128 0 : for_each_irq_desc(i, desc) {
129 0 : if (!i)
130 0 : continue;
131 :
132 0 : if (i == irq) /* Already tried */
133 0 : continue;
134 :
135 0 : if (try_one_irq(desc, false))
136 0 : ok = 1;
137 : }
138 : out:
139 0 : atomic_dec(&irq_poll_active);
140 : /* So the caller can adjust the irq error counts */
141 0 : return ok;
142 : }
143 :
144 0 : static void poll_spurious_irqs(struct timer_list *unused)
145 : {
146 : struct irq_desc *desc;
147 : int i;
148 :
149 0 : if (atomic_inc_return(&irq_poll_active) != 1)
150 : goto out;
151 0 : irq_poll_cpu = smp_processor_id();
152 :
153 0 : for_each_irq_desc(i, desc) {
154 : unsigned int state;
155 :
156 0 : if (!i)
157 0 : continue;
158 :
159 : /* Racy but it doesn't matter */
160 0 : state = desc->istate;
161 0 : barrier();
162 0 : if (!(state & IRQS_SPURIOUS_DISABLED))
163 0 : continue;
164 :
165 : local_irq_disable();
166 0 : try_one_irq(desc, true);
167 : local_irq_enable();
168 : }
169 : out:
170 0 : atomic_dec(&irq_poll_active);
171 0 : mod_timer(&poll_spurious_irq_timer,
172 : jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
173 0 : }
174 :
175 : static inline int bad_action_ret(irqreturn_t action_ret)
176 : {
177 2943 : unsigned int r = action_ret;
178 :
179 2943 : if (likely(r <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
180 : return 0;
181 : return 1;
182 : }
183 :
184 : /*
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.
188 : *
189 : * (The other 100-of-100,000 interrupts may have been a correctly
190 : * functioning device sharing an IRQ with the failing one)
191 : */
192 0 : static void __report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
193 : {
194 0 : unsigned int irq = irq_desc_get_irq(desc);
195 : struct irqaction *action;
196 : unsigned long flags;
197 :
198 0 : if (bad_action_ret(action_ret)) {
199 0 : printk(KERN_ERR "irq event %d: bogus return value %x\n",
200 : irq, action_ret);
201 : } else {
202 0 : printk(KERN_ERR "irq %d: nobody cared (try booting with "
203 : "the \"irqpoll\" option)\n", irq);
204 : }
205 0 : dump_stack();
206 0 : printk(KERN_ERR "handlers:\n");
207 :
208 : /*
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().
213 : */
214 0 : raw_spin_lock_irqsave(&desc->lock, flags);
215 0 : for_each_action_of_desc(desc, action) {
216 0 : printk(KERN_ERR "[<%p>] %ps", action->handler, action->handler);
217 0 : if (action->thread_fn)
218 0 : printk(KERN_CONT " threaded [<%p>] %ps",
219 : action->thread_fn, action->thread_fn);
220 0 : printk(KERN_CONT "\n");
221 : }
222 0 : raw_spin_unlock_irqrestore(&desc->lock, flags);
223 0 : }
224 :
225 : static void report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
226 : {
227 : static int count = 100;
228 :
229 0 : if (count > 0) {
230 0 : count--;
231 0 : __report_bad_irq(desc, action_ret);
232 : }
233 : }
234 :
235 : static inline int
236 : try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
237 : irqreturn_t action_ret)
238 : {
239 : struct irqaction *action;
240 :
241 2943 : if (!irqfixup)
242 : return 0;
243 :
244 : /* We didn't actually handle the IRQ - see if it was misrouted? */
245 0 : if (action_ret == IRQ_NONE)
246 : return 1;
247 :
248 : /*
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)
252 : */
253 0 : if (irqfixup < 2)
254 : return 0;
255 :
256 0 : if (!irq)
257 : return 1;
258 :
259 : /*
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.
264 : */
265 0 : action = desc->action;
266 0 : barrier();
267 0 : return action && (action->flags & IRQF_IRQPOLL);
268 : }
269 :
270 : #define SPURIOUS_DEFERRED 0x80000000
271 :
272 2943 : void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
273 : {
274 : unsigned int irq;
275 :
276 5886 : if (desc->istate & IRQS_POLL_INPROGRESS ||
277 2943 : irq_settings_is_polled(desc))
278 : return;
279 :
280 2943 : if (bad_action_ret(action_ret)) {
281 : report_bad_irq(desc, action_ret);
282 : return;
283 : }
284 :
285 : /*
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
291 : * result.
292 : *
293 : * So in case a thread is woken, we just note the fact and
294 : * defer the analysis to the next hardware interrupt.
295 : *
296 : * The threaded handlers store whether they successfully
297 : * handled an interrupt and we check whether that number
298 : * changed versus the last invocation.
299 : *
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.
304 : */
305 2943 : if (action_ret & IRQ_WAKE_THREAD) {
306 : /*
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
310 : * interrupt.
311 : */
312 0 : if (action_ret == IRQ_WAKE_THREAD) {
313 : int handled;
314 : /*
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.
321 : */
322 0 : if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) {
323 0 : desc->threads_handled_last |= SPURIOUS_DEFERRED;
324 0 : return;
325 : }
326 : /*
327 : * Check whether one of the threaded handlers
328 : * returned IRQ_HANDLED since the last
329 : * interrupt happened.
330 : *
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.
337 : */
338 0 : handled = atomic_read(&desc->threads_handled);
339 0 : handled |= SPURIOUS_DEFERRED;
340 0 : if (handled != desc->threads_handled_last) {
341 0 : action_ret = IRQ_HANDLED;
342 : /*
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
348 : * account for it.
349 : */
350 0 : desc->threads_handled_last = handled;
351 : } else {
352 : /*
353 : * None of the threaded handlers felt
354 : * responsible for the last interrupt
355 : *
356 : * We keep the SPURIOUS_DEFERRED bit
357 : * set in threads_handled_last as we
358 : * need to account for the current
359 : * interrupt as well.
360 : */
361 : action_ret = IRQ_NONE;
362 : }
363 : } else {
364 : /*
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.
369 : *
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.
380 : */
381 0 : desc->threads_handled_last &= ~SPURIOUS_DEFERRED;
382 : }
383 : }
384 :
385 2943 : if (unlikely(action_ret == IRQ_NONE)) {
386 : /*
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
390 : * working systems
391 : */
392 0 : if (time_after(jiffies, desc->last_unhandled + HZ/10))
393 0 : desc->irqs_unhandled = 1;
394 : else
395 0 : desc->irqs_unhandled++;
396 0 : desc->last_unhandled = jiffies;
397 : }
398 :
399 2943 : irq = irq_desc_get_irq(desc);
400 5886 : if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
401 0 : int ok = misrouted_irq(irq);
402 0 : if (action_ret == IRQ_NONE)
403 0 : desc->irqs_unhandled -= ok;
404 : }
405 :
406 2943 : if (likely(!desc->irqs_unhandled))
407 : return;
408 :
409 : /* Now getting into unhandled irq detection */
410 0 : desc->irq_count++;
411 0 : if (likely(desc->irq_count < 100000))
412 : return;
413 :
414 0 : desc->irq_count = 0;
415 0 : if (unlikely(desc->irqs_unhandled > 99900)) {
416 : /*
417 : * The interrupt is stuck
418 : */
419 0 : __report_bad_irq(desc, action_ret);
420 : /*
421 : * Now kill the IRQ
422 : */
423 0 : printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
424 0 : desc->istate |= IRQS_SPURIOUS_DISABLED;
425 0 : desc->depth++;
426 0 : irq_disable(desc);
427 :
428 0 : mod_timer(&poll_spurious_irq_timer,
429 : jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
430 : }
431 0 : desc->irqs_unhandled = 0;
432 : }
433 :
434 : bool noirqdebug __read_mostly;
435 :
436 0 : int noirqdebug_setup(char *str)
437 : {
438 0 : noirqdebug = 1;
439 0 : printk(KERN_INFO "IRQ lockup detection disabled\n");
440 :
441 0 : return 1;
442 : }
443 :
444 : __setup("noirqdebug", noirqdebug_setup);
445 : module_param(noirqdebug, bool, 0644);
446 : MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
447 :
448 0 : static int __init irqfixup_setup(char *str)
449 : {
450 : if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
451 : pr_warn("irqfixup boot option not supported with PREEMPT_RT\n");
452 : return 1;
453 : }
454 0 : irqfixup = 1;
455 0 : printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
456 0 : printk(KERN_WARNING "This may impact system performance.\n");
457 :
458 : return 1;
459 : }
460 :
461 : __setup("irqfixup", irqfixup_setup);
462 : module_param(irqfixup, int, 0644);
463 :
464 0 : static int __init irqpoll_setup(char *str)
465 : {
466 : if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
467 : pr_warn("irqpoll boot option not supported with PREEMPT_RT\n");
468 : return 1;
469 : }
470 0 : irqfixup = 2;
471 0 : printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
472 : "enabled\n");
473 0 : printk(KERN_WARNING "This may significantly impact system "
474 : "performance\n");
475 : return 1;
476 : }
477 :
478 : __setup("irqpoll", irqpoll_setup);
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