c9a78ba30b6f5718a69d9dcdbd1634b64c748174
[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) || !action->next)
88                 goto out;
89
90         /* Already running on another processor */
91         if (irqd_irq_inprogress(&desc->irq_data)) {
92                 /*
93                  * Already running: If it is shared get the other
94                  * CPU to go looking for our mystery interrupt too
95                  */
96                 desc->istate |= IRQS_PENDING;
97                 goto out;
98         }
99
100         /* Mark it poll in progress */
101         desc->istate |= IRQS_POLL_INPROGRESS;
102         do {
103                 if (handle_irq_event(desc) == IRQ_HANDLED)
104                         ret = IRQ_HANDLED;
105                 action = desc->action;
106         } while ((desc->istate & IRQS_PENDING) && action);
107         desc->istate &= ~IRQS_POLL_INPROGRESS;
108 out:
109         raw_spin_unlock(&desc->lock);
110         return ret == IRQ_HANDLED;
111 }
112
113 static int misrouted_irq(int irq)
114 {
115         struct irq_desc *desc;
116         int i, ok = 0;
117
118         if (atomic_inc_return(&irq_poll_active) == 1)
119                 goto out;
120
121         irq_poll_cpu = smp_processor_id();
122
123         for_each_irq_desc(i, desc) {
124                 if (!i)
125                          continue;
126
127                 if (i == irq)   /* Already tried */
128                         continue;
129
130                 if (try_one_irq(i, desc, false))
131                         ok = 1;
132         }
133 out:
134         atomic_dec(&irq_poll_active);
135         /* So the caller can adjust the irq error counts */
136         return ok;
137 }
138
139 static void poll_spurious_irqs(unsigned long dummy)
140 {
141         struct irq_desc *desc;
142         int i;
143
144         if (atomic_inc_return(&irq_poll_active) != 1)
145                 goto out;
146         irq_poll_cpu = smp_processor_id();
147
148         for_each_irq_desc(i, desc) {
149                 unsigned int state;
150
151                 if (!i)
152                          continue;
153
154                 /* Racy but it doesn't matter */
155                 state = desc->istate;
156                 barrier();
157                 if (!(state & IRQS_SPURIOUS_DISABLED))
158                         continue;
159
160                 local_irq_disable();
161                 try_one_irq(i, desc, true);
162                 local_irq_enable();
163         }
164 out:
165         atomic_dec(&irq_poll_active);
166         mod_timer(&poll_spurious_irq_timer,
167                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
168 }
169
170 /*
171  * If 99,900 of the previous 100,000 interrupts have not been handled
172  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
173  * and try to turn the IRQ off.
174  *
175  * (The other 100-of-100,000 interrupts may have been a correctly
176  *  functioning device sharing an IRQ with the failing one)
177  */
178 static void
179 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
180                  irqreturn_t action_ret)
181 {
182         struct irqaction *action;
183         unsigned long flags;
184
185         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
186                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
187                                 irq, action_ret);
188         } else {
189                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
190                                 "the \"irqpoll\" option)\n", irq);
191         }
192         dump_stack();
193         printk(KERN_ERR "handlers:\n");
194
195         /*
196          * We need to take desc->lock here. note_interrupt() is called
197          * w/o desc->lock held, but IRQ_PROGRESS set. We might race
198          * with something else removing an action. It's ok to take
199          * desc->lock here. See synchronize_irq().
200          */
201         raw_spin_lock_irqsave(&desc->lock, flags);
202         action = desc->action;
203         while (action) {
204                 printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
205                 if (action->thread_fn)
206                         printk(KERN_CONT " threaded [<%p>] %pf",
207                                         action->thread_fn, action->thread_fn);
208                 printk(KERN_CONT "\n");
209                 action = action->next;
210         }
211         raw_spin_unlock_irqrestore(&desc->lock, flags);
212 }
213
214 static void
215 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
216 {
217         static int count = 100;
218
219         if (count > 0) {
220                 count--;
221                 __report_bad_irq(irq, desc, action_ret);
222         }
223 }
224
225 static inline int
226 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
227                   irqreturn_t action_ret)
228 {
229         struct irqaction *action;
230
231         if (!irqfixup)
232                 return 0;
233
234         /* We didn't actually handle the IRQ - see if it was misrouted? */
235         if (action_ret == IRQ_NONE)
236                 return 1;
237
238         /*
239          * But for 'irqfixup == 2' we also do it for handled interrupts if
240          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
241          * traditional PC timer interrupt.. Legacy)
242          */
243         if (irqfixup < 2)
244                 return 0;
245
246         if (!irq)
247                 return 1;
248
249         /*
250          * Since we don't get the descriptor lock, "action" can
251          * change under us.  We don't really care, but we don't
252          * want to follow a NULL pointer. So tell the compiler to
253          * just load it once by using a barrier.
254          */
255         action = desc->action;
256         barrier();
257         return action && (action->flags & IRQF_IRQPOLL);
258 }
259
260 void note_interrupt(unsigned int irq, struct irq_desc *desc,
261                     irqreturn_t action_ret)
262 {
263         if (desc->istate & IRQS_POLL_INPROGRESS)
264                 return;
265
266         if (unlikely(action_ret != IRQ_HANDLED)) {
267                 /*
268                  * If we are seeing only the odd spurious IRQ caused by
269                  * bus asynchronicity then don't eventually trigger an error,
270                  * otherwise the counter becomes a doomsday timer for otherwise
271                  * working systems
272                  */
273                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
274                         desc->irqs_unhandled = 1;
275                 else
276                         desc->irqs_unhandled++;
277                 desc->last_unhandled = jiffies;
278                 if (unlikely(action_ret != IRQ_NONE))
279                         report_bad_irq(irq, desc, action_ret);
280         }
281
282         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
283                 int ok = misrouted_irq(irq);
284                 if (action_ret == IRQ_NONE)
285                         desc->irqs_unhandled -= ok;
286         }
287
288         desc->irq_count++;
289         if (likely(desc->irq_count < 100000))
290                 return;
291
292         desc->irq_count = 0;
293         if (unlikely(desc->irqs_unhandled > 99900)) {
294                 /*
295                  * The interrupt is stuck
296                  */
297                 __report_bad_irq(irq, desc, action_ret);
298                 /*
299                  * Now kill the IRQ
300                  */
301                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
302                 desc->istate |= IRQS_SPURIOUS_DISABLED;
303                 desc->depth++;
304                 irq_disable(desc);
305
306                 mod_timer(&poll_spurious_irq_timer,
307                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
308         }
309         desc->irqs_unhandled = 0;
310 }
311
312 int noirqdebug __read_mostly;
313
314 int noirqdebug_setup(char *str)
315 {
316         noirqdebug = 1;
317         printk(KERN_INFO "IRQ lockup detection disabled\n");
318
319         return 1;
320 }
321
322 __setup("noirqdebug", noirqdebug_setup);
323 module_param(noirqdebug, bool, 0644);
324 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
325
326 static int __init irqfixup_setup(char *str)
327 {
328         irqfixup = 1;
329         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
330         printk(KERN_WARNING "This may impact system performance.\n");
331
332         return 1;
333 }
334
335 __setup("irqfixup", irqfixup_setup);
336 module_param(irqfixup, int, 0644);
337
338 static int __init irqpoll_setup(char *str)
339 {
340         irqfixup = 2;
341         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
342                                 "enabled\n");
343         printk(KERN_WARNING "This may significantly impact system "
344                                 "performance\n");
345         return 1;
346 }
347
348 __setup("irqpoll", irqpoll_setup);