Branch data 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 : : {
38 [ # # # # : 0 : 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 [ # # ]: 0 : while (irqd_irq_inprogress(&desc->irq_data))
47 : 0 : cpu_relax();
48 : 0 : raw_spin_lock(&desc->lock);
49 [ # # ]: 0 : } while (irqd_irq_inprogress(&desc->irq_data));
50 : : /* Might have been disabled in meantime */
51 [ # # # # ]: 0 : 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 : : */
61 : 0 : static int try_one_irq(struct irq_desc *desc, bool force)
62 : : {
63 : : irqreturn_t ret = IRQ_NONE;
64 : : struct irqaction *action;
65 : :
66 : 0 : 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 [ # # # # ]: 0 : if (irq_settings_is_per_cpu(desc) ||
73 [ # # ]: 0 : 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 [ # # # # ]: 0 : 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 : 0 : action = desc->action;
89 [ # # # # ]: 0 : if (!action || !(action->flags & IRQF_SHARED) ||
90 : : (action->flags & __IRQF_TIMER))
91 : : goto out;
92 : :
93 : : /* Already running on another processor */
94 [ # # ]: 0 : 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 : 0 : desc->istate |= IRQS_PENDING;
100 : 0 : goto out;
101 : : }
102 : :
103 : : /* Mark it poll in progress */
104 : 0 : desc->istate |= IRQS_POLL_INPROGRESS;
105 : : do {
106 [ # # ]: 0 : if (handle_irq_event(desc) == IRQ_HANDLED)
107 : : ret = IRQ_HANDLED;
108 : : /* Make sure that there is still a valid action */
109 : 0 : action = desc->action;
110 [ # # # # ]: 0 : } while ((desc->istate & IRQS_PENDING) && action);
111 : 0 : desc->istate &= ~IRQS_POLL_INPROGRESS;
112 : : out:
113 : : raw_spin_unlock(&desc->lock);
114 : 0 : return ret == IRQ_HANDLED;
115 : : }
116 : :
117 : 0 : static int misrouted_irq(int irq)
118 : : {
119 : : struct irq_desc *desc;
120 : : int i, ok = 0;
121 : :
122 [ # # ]: 0 : if (atomic_inc_return(&irq_poll_active) != 1)
123 : : goto out;
124 : :
125 : 0 : irq_poll_cpu = smp_processor_id();
126 : :
127 [ # # # # ]: 0 : for_each_irq_desc(i, desc) {
128 [ # # ]: 0 : if (!i)
129 : 0 : continue;
130 : :
131 [ # # ]: 0 : if (i == irq) /* Already tried */
132 : 0 : continue;
133 : :
134 [ # # ]: 0 : if (try_one_irq(desc, false))
135 : : ok = 1;
136 : : }
137 : : out:
138 : : atomic_dec(&irq_poll_active);
139 : : /* So the caller can adjust the irq error counts */
140 : 0 : return ok;
141 : : }
142 : :
143 : 0 : static void poll_spurious_irqs(struct timer_list *unused)
144 : : {
145 : : struct irq_desc *desc;
146 : : int i;
147 : :
148 [ # # ]: 0 : if (atomic_inc_return(&irq_poll_active) != 1)
149 : : goto out;
150 : 0 : irq_poll_cpu = smp_processor_id();
151 : :
152 [ # # # # ]: 0 : for_each_irq_desc(i, desc) {
153 : : unsigned int state;
154 : :
155 [ # # ]: 0 : if (!i)
156 : 0 : continue;
157 : :
158 : : /* Racy but it doesn't matter */
159 : 0 : state = desc->istate;
160 : 0 : barrier();
161 [ # # ]: 0 : if (!(state & IRQS_SPURIOUS_DISABLED))
162 : 0 : continue;
163 : :
164 : 0 : local_irq_disable();
165 : 0 : try_one_irq(desc, true);
166 : 0 : local_irq_enable();
167 : : }
168 : : out:
169 : : atomic_dec(&irq_poll_active);
170 : 0 : mod_timer(&poll_spurious_irq_timer,
171 : : jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
172 : 0 : }
173 : :
174 : : static inline int bad_action_ret(irqreturn_t action_ret)
175 : : {
176 : : unsigned int r = action_ret;
177 : :
178 [ - + # # ]: 11762417 : 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 : : */
191 : 0 : static 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 [ # # ]: 0 : if (bad_action_ret(action_ret)) {
198 : 0 : printk(KERN_ERR "irq event %d: bogus return value %x\n",
199 : : irq, action_ret);
200 : : } else {
201 : 0 : printk(KERN_ERR "irq %d: nobody cared (try booting with "
202 : : "the \"irqpoll\" option)\n", irq);
203 : : }
204 : 0 : dump_stack();
205 : 0 : 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 : 0 : raw_spin_lock_irqsave(&desc->lock, flags);
214 [ # # ]: 0 : for_each_action_of_desc(desc, action) {
215 : 0 : printk(KERN_ERR "[<%p>] %ps", action->handler, action->handler);
216 [ # # ]: 0 : if (action->thread_fn)
217 : 0 : printk(KERN_CONT " threaded [<%p>] %ps",
218 : : action->thread_fn, action->thread_fn);
219 : 0 : printk(KERN_CONT "\n");
220 : : }
221 : 0 : raw_spin_unlock_irqrestore(&desc->lock, flags);
222 : 0 : }
223 : :
224 : : static void report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
225 : : {
226 : : static int count = 100;
227 : :
228 [ # # ]: 0 : if (count > 0) {
229 : 0 : count--;
230 : 0 : __report_bad_irq(desc, action_ret);
231 : : }
232 : : }
233 : :
234 : : static inline int
235 : : try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
236 : : irqreturn_t action_ret)
237 : : {
238 : : struct irqaction *action;
239 : :
240 [ - + ]: 11762417 : if (!irqfixup)
241 : : return 0;
242 : :
243 : : /* We didn't actually handle the IRQ - see if it was misrouted? */
244 [ # # ]: 0 : 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 [ # # ]: 0 : if (irqfixup < 2)
253 : : return 0;
254 : :
255 [ # # ]: 0 : 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 : 0 : action = desc->action;
265 : 0 : barrier();
266 [ # # # # ]: 0 : return action && (action->flags & IRQF_IRQPOLL);
267 : : }
268 : :
269 : : #define SPURIOUS_DEFERRED 0x80000000
270 : :
271 : 11762417 : void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
272 : : {
273 : : unsigned int irq;
274 : :
275 [ + - + - ]: 23524834 : if (desc->istate & IRQS_POLL_INPROGRESS ||
276 : : irq_settings_is_polled(desc))
277 : : return;
278 : :
279 [ - + ]: 11762417 : 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 [ - + ]: 11762417 : 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 [ # # ]: 0 : 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 [ # # ]: 0 : if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) {
322 : 0 : desc->threads_handled_last |= SPURIOUS_DEFERRED;
323 : 0 : 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 : 0 : handled |= SPURIOUS_DEFERRED;
339 [ # # ]: 0 : 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 : 0 : 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 : 0 : desc->threads_handled_last &= ~SPURIOUS_DEFERRED;
381 : : }
382 : : }
383 : :
384 [ - + ]: 11762417 : 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 [ # # ]: 0 : if (time_after(jiffies, desc->last_unhandled + HZ/10))
392 : 0 : desc->irqs_unhandled = 1;
393 : : else
394 : 0 : desc->irqs_unhandled++;
395 : 0 : desc->last_unhandled = jiffies;
396 : : }
397 : :
398 : : irq = irq_desc_get_irq(desc);
399 [ - + ]: 11762417 : if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
400 : 0 : int ok = misrouted_irq(irq);
401 [ # # ]: 0 : if (action_ret == IRQ_NONE)
402 : 0 : desc->irqs_unhandled -= ok;
403 : : }
404 : :
405 : 11762417 : desc->irq_count++;
406 [ - + ]: 11762417 : if (likely(desc->irq_count < 100000))
407 : : return;
408 : :
409 : 0 : desc->irq_count = 0;
410 [ # # ]: 0 : if (unlikely(desc->irqs_unhandled > 99900)) {
411 : : /*
412 : : * The interrupt is stuck
413 : : */
414 : 0 : __report_bad_irq(desc, action_ret);
415 : : /*
416 : : * Now kill the IRQ
417 : : */
418 : 0 : printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
419 : 0 : desc->istate |= IRQS_SPURIOUS_DISABLED;
420 : 0 : desc->depth++;
421 : 0 : irq_disable(desc);
422 : :
423 : 0 : mod_timer(&poll_spurious_irq_timer,
424 : : jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
425 : : }
426 : 0 : desc->irqs_unhandled = 0;
427 : : }
428 : :
429 : : bool noirqdebug __read_mostly;
430 : :
431 : 0 : int noirqdebug_setup(char *str)
432 : : {
433 : 0 : noirqdebug = 1;
434 : 0 : printk(KERN_INFO "IRQ lockup detection disabled\n");
435 : :
436 : 0 : return 1;
437 : : }
438 : :
439 : : __setup("noirqdebug", noirqdebug_setup);
440 : : module_param(noirqdebug, bool, 0644);
441 : : MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
442 : :
443 : 0 : static int __init irqfixup_setup(char *str)
444 : : {
445 : 0 : irqfixup = 1;
446 : 0 : printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
447 : 0 : printk(KERN_WARNING "This may impact system performance.\n");
448 : :
449 : 0 : return 1;
450 : : }
451 : :
452 : : __setup("irqfixup", irqfixup_setup);
453 : : module_param(irqfixup, int, 0644);
454 : :
455 : 0 : static int __init irqpoll_setup(char *str)
456 : : {
457 : 0 : irqfixup = 2;
458 : 0 : printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
459 : : "enabled\n");
460 : 0 : printk(KERN_WARNING "This may significantly impact system "
461 : : "performance\n");
462 : 0 : return 1;
463 : : }
464 : :
465 : : __setup("irqpoll", irqpoll_setup);
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