dc813a948be2379fe20a0218e1d270212b8408d3
[linux-3.10.git] / kernel / irq / spurious.c
1 /*
2  * linux/kernel/irq/spurious.c
3  *
4  * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5  *
6  * This file contains spurious interrupt handling.
7  */
8
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>
16
17 #include "internals.h"
18
19 static int irqfixup __read_mostly;
20
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;
26
27 /*
28  * We wait here for a poller to finish.
29  *
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.
33  *
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.
37  */
38 bool irq_wait_for_poll(struct irq_desc *desc)
39 {
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))
43                 return false;
44
45 #ifdef CONFIG_SMP
46         do {
47                 raw_spin_unlock(&desc->lock);
48                 while (irqd_irq_inprogress(&desc->irq_data))
49                         cpu_relax();
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;
54 #else
55         return false;
56 #endif
57 }
58
59
60 /*
61  * Recovery handler for misrouted interrupts.
62  */
63 static int try_one_irq(int irq, struct irq_desc *desc, bool force)
64 {
65         irqreturn_t ret = IRQ_NONE;
66         struct irqaction *action;
67
68         raw_spin_lock(&desc->lock);
69
70         /* PER_CPU and nested thread interrupts are never polled */
71         if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc))
72                 goto out;
73
74         /*
75          * Do not poll disabled interrupts unless the spurious
76          * disabled poller asks explicitely.
77          */
78         if (irqd_irq_disabled(&desc->irq_data) && !force)
79                 goto out;
80
81         /*
82          * All handlers must agree on IRQF_SHARED, so we test just the
83          * first. Check for action->next as well.
84          */
85         action = desc->action;
86         if (!action || !(action->flags & IRQF_SHARED) ||
87             (action->flags & __IRQF_TIMER) ||
88             (action->handler(irq, action->dev_id) == IRQ_HANDLED) ||
89             !action->next)
90                 goto out;
91
92         /* Already running on another processor */
93         if (irqd_irq_inprogress(&desc->irq_data)) {
94                 /*
95                  * Already running: If it is shared get the other
96                  * CPU to go looking for our mystery interrupt too
97                  */
98                 desc->istate |= IRQS_PENDING;
99                 goto out;
100         }
101
102         /* Mark it poll in progress */
103         desc->istate |= IRQS_POLL_INPROGRESS;
104         do {
105                 if (handle_irq_event(desc) == IRQ_HANDLED)
106                         ret = IRQ_HANDLED;
107                 action = desc->action;
108         } while ((desc->istate & IRQS_PENDING) && action);
109         desc->istate &= ~IRQS_POLL_INPROGRESS;
110 out:
111         raw_spin_unlock(&desc->lock);
112         return ret == IRQ_HANDLED;
113 }
114
115 static int misrouted_irq(int irq)
116 {
117         struct irq_desc *desc;
118         int i, ok = 0;
119
120         if (atomic_inc_return(&irq_poll_active) != 1)
121                 goto out;
122
123         irq_poll_cpu = smp_processor_id();
124
125         for_each_irq_desc(i, desc) {
126                 if (!i)
127                          continue;
128
129                 if (i == irq)   /* Already tried */
130                         continue;
131
132                 if (try_one_irq(i, desc, false))
133                         ok = 1;
134         }
135 out:
136         atomic_dec(&irq_poll_active);
137         /* So the caller can adjust the irq error counts */
138         return ok;
139 }
140
141 static void poll_spurious_irqs(unsigned long dummy)
142 {
143         struct irq_desc *desc;
144         int i;
145
146         if (atomic_inc_return(&irq_poll_active) != 1)
147                 goto out;
148         irq_poll_cpu = smp_processor_id();
149
150         for_each_irq_desc(i, desc) {
151                 unsigned int state;
152
153                 if (!i)
154                          continue;
155
156                 /* Racy but it doesn't matter */
157                 state = desc->istate;
158                 barrier();
159                 if (!(state & IRQS_SPURIOUS_DISABLED))
160                         continue;
161
162                 local_irq_disable();
163                 try_one_irq(i, desc, true);
164                 local_irq_enable();
165         }
166 out:
167         atomic_dec(&irq_poll_active);
168         mod_timer(&poll_spurious_irq_timer,
169                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
170 }
171
172 static inline int bad_action_ret(irqreturn_t action_ret)
173 {
174         if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
175                 return 0;
176         return 1;
177 }
178
179 /*
180  * If 99,900 of the previous 100,000 interrupts have not been handled
181  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
182  * and try to turn the IRQ off.
183  *
184  * (The other 100-of-100,000 interrupts may have been a correctly
185  *  functioning device sharing an IRQ with the failing one)
186  */
187 static void
188 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
189                  irqreturn_t action_ret)
190 {
191         struct irqaction *action;
192         unsigned long flags;
193
194         if (bad_action_ret(action_ret)) {
195                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
196                                 irq, action_ret);
197         } else {
198                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
199                                 "the \"irqpoll\" option)\n", irq);
200         }
201         dump_stack();
202         printk(KERN_ERR "handlers:\n");
203
204         /*
205          * We need to take desc->lock here. note_interrupt() is called
206          * w/o desc->lock held, but IRQ_PROGRESS set. We might race
207          * with something else removing an action. It's ok to take
208          * desc->lock here. See synchronize_irq().
209          */
210         raw_spin_lock_irqsave(&desc->lock, flags);
211         action = desc->action;
212         while (action) {
213                 printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
214                 if (action->thread_fn)
215                         printk(KERN_CONT " threaded [<%p>] %pf",
216                                         action->thread_fn, action->thread_fn);
217                 printk(KERN_CONT "\n");
218                 action = action->next;
219         }
220         raw_spin_unlock_irqrestore(&desc->lock, flags);
221 }
222
223 static void
224 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
225 {
226         static int count = 100;
227
228         if (count > 0) {
229                 count--;
230                 __report_bad_irq(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         if (!irqfixup)
241                 return 0;
242
243         /* We didn't actually handle the IRQ - see if it was misrouted? */
244         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         if (irqfixup < 2)
253                 return 0;
254
255         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         action = desc->action;
265         barrier();
266         return action && (action->flags & IRQF_IRQPOLL);
267 }
268
269 void note_interrupt(unsigned int irq, struct irq_desc *desc,
270                     irqreturn_t action_ret)
271 {
272         if (desc->istate & IRQS_POLL_INPROGRESS)
273                 return;
274
275         /* we get here again via the threaded handler */
276         if (action_ret == IRQ_WAKE_THREAD)
277                 return;
278
279         if (bad_action_ret(action_ret)) {
280                 report_bad_irq(irq, desc, action_ret);
281                 return;
282         }
283
284         if (unlikely(action_ret == IRQ_NONE)) {
285                 /*
286                  * If we are seeing only the odd spurious IRQ caused by
287                  * bus asynchronicity then don't eventually trigger an error,
288                  * otherwise the counter becomes a doomsday timer for otherwise
289                  * working systems
290                  */
291                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
292                         desc->irqs_unhandled = 1;
293                 else
294                         desc->irqs_unhandled++;
295                 desc->last_unhandled = jiffies;
296         }
297
298         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
299                 int ok = misrouted_irq(irq);
300                 if (action_ret == IRQ_NONE)
301                         desc->irqs_unhandled -= ok;
302         }
303
304         desc->irq_count++;
305         if (likely(desc->irq_count < 100000))
306                 return;
307
308         desc->irq_count = 0;
309         if (unlikely(desc->irqs_unhandled > 99900)) {
310                 /*
311                  * The interrupt is stuck
312                  */
313                 __report_bad_irq(irq, desc, action_ret);
314                 /*
315                  * Now kill the IRQ
316                  */
317                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
318                 desc->istate |= IRQS_SPURIOUS_DISABLED;
319                 desc->depth++;
320                 irq_disable(desc);
321
322                 mod_timer(&poll_spurious_irq_timer,
323                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
324         }
325         desc->irqs_unhandled = 0;
326 }
327
328 int noirqdebug __read_mostly;
329
330 int noirqdebug_setup(char *str)
331 {
332         noirqdebug = 1;
333         printk(KERN_INFO "IRQ lockup detection disabled\n");
334
335         return 1;
336 }
337
338 __setup("noirqdebug", noirqdebug_setup);
339 module_param(noirqdebug, bool, 0644);
340 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
341
342 static int __init irqfixup_setup(char *str)
343 {
344         irqfixup = 1;
345         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
346         printk(KERN_WARNING "This may impact system performance.\n");
347
348         return 1;
349 }
350
351 __setup("irqfixup", irqfixup_setup);
352 module_param(irqfixup, int, 0644);
353
354 static int __init irqpoll_setup(char *str)
355 {
356         irqfixup = 2;
357         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
358                                 "enabled\n");
359         printk(KERN_WARNING "This may significantly impact system "
360                                 "performance\n");
361         return 1;
362 }
363
364 __setup("irqpoll", irqpoll_setup);