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 : : __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 : 0 : do {
46 : 0 : raw_spin_unlock(&desc->lock);
47 [ # # ]: 0 : while (irqd_irq_inprogress(&desc->irq_data))
48 : 0 : cpu_relax();
49 : 0 : raw_spin_lock(&desc->lock);
50 [ # # ]: 0 : } while (irqd_irq_inprogress(&desc->irq_data));
51 : : /* Might have been disabled in meantime */
52 [ # # # # ]: 0 : 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 : 0 : 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 : : irq_settings_is_polled(desc))
76 : 0 : 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 : 0 : 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 : 0 : 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 : 0 : 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 : 0 : 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 : 0 : struct irq_desc *desc;
121 : 0 : int i, ok = 0;
122 : :
123 [ # # ]: 0 : if (atomic_inc_return(&irq_poll_active) != 1)
124 : 0 : 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 : 0 : 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 : 0 : struct irq_desc *desc;
147 : 0 : int i;
148 : :
149 [ # # ]: 0 : if (atomic_inc_return(&irq_poll_active) != 1)
150 : 0 : goto out;
151 : 0 : irq_poll_cpu = smp_processor_id();
152 : :
153 [ # # # # ]: 0 : for_each_irq_desc(i, desc) {
154 : 0 : 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 : 0 : local_irq_disable();
166 : 0 : try_one_irq(desc, true);
167 : 0 : local_irq_enable();
168 : : }
169 : 0 : 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 : 54346 : static inline int bad_action_ret(irqreturn_t action_ret)
176 : : {
177 : 54346 : unsigned int r = action_ret;
178 : :
179 : 54346 : if (likely(r <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
180 : 54346 : 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 : 0 : struct irqaction *action;
196 : 0 : 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 : 0 : static void report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
226 : : {
227 : 0 : 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 : 54346 : try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
237 : : irqreturn_t action_ret)
238 : : {
239 : 54346 : struct irqaction *action;
240 : :
241 : 54346 : 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 : 54346 : void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
273 : : {
274 : 54346 : unsigned int irq;
275 : :
276 [ + - + - ]: 54346 : if (desc->istate & IRQS_POLL_INPROGRESS ||
277 [ + - ]: 54346 : irq_settings_is_polled(desc))
278 : : return;
279 : :
280 [ - + ]: 54346 : if (bad_action_ret(action_ret)) {
281 [ # # ]: 0 : report_bad_irq(desc, action_ret);
282 : 0 : 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 [ - + ]: 54346 : 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 : 0 : 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 [ + + ]: 54346 : 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 [ + + ]: 8342 : if (time_after(jiffies, desc->last_unhandled + HZ/10))
393 : 129 : desc->irqs_unhandled = 1;
394 : : else
395 : 8213 : desc->irqs_unhandled++;
396 : 8342 : desc->last_unhandled = jiffies;
397 : : }
398 : :
399 [ - + ]: 54346 : irq = irq_desc_get_irq(desc);
400 [ - + - + ]: 54346 : 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 : 54346 : desc->irq_count++;
407 [ - + ]: 54346 : if (likely(desc->irq_count < 100000))
408 : : return;
409 : :
410 : 0 : desc->irq_count = 0;
411 [ # # ]: 0 : if (unlikely(desc->irqs_unhandled > 99900)) {
412 : : /*
413 : : * The interrupt is stuck
414 : : */
415 : 0 : __report_bad_irq(desc, action_ret);
416 : : /*
417 : : * Now kill the IRQ
418 : : */
419 : 0 : printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
420 : 0 : desc->istate |= IRQS_SPURIOUS_DISABLED;
421 : 0 : desc->depth++;
422 : 0 : irq_disable(desc);
423 : :
424 : 0 : mod_timer(&poll_spurious_irq_timer,
425 : : jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
426 : : }
427 : 0 : desc->irqs_unhandled = 0;
428 : : }
429 : :
430 : : bool noirqdebug __read_mostly;
431 : :
432 : 0 : int noirqdebug_setup(char *str)
433 : : {
434 : 0 : noirqdebug = 1;
435 : 0 : printk(KERN_INFO "IRQ lockup detection disabled\n");
436 : :
437 : 0 : return 1;
438 : : }
439 : :
440 : : __setup("noirqdebug", noirqdebug_setup);
441 : : module_param(noirqdebug, bool, 0644);
442 : : MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
443 : :
444 : 0 : static int __init irqfixup_setup(char *str)
445 : : {
446 : 0 : irqfixup = 1;
447 : 0 : printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
448 : 0 : printk(KERN_WARNING "This may impact system performance.\n");
449 : :
450 : 0 : return 1;
451 : : }
452 : :
453 : : __setup("irqfixup", irqfixup_setup);
454 : : module_param(irqfixup, int, 0644);
455 : :
456 : 0 : static int __init irqpoll_setup(char *str)
457 : : {
458 : 0 : irqfixup = 2;
459 : 0 : printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
460 : : "enabled\n");
461 : 0 : printk(KERN_WARNING "This may significantly impact system "
462 : : "performance\n");
463 : 0 : return 1;
464 : : }
465 : :
466 : : __setup("irqpoll", irqpoll_setup);
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