Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso...
[firefly-linux-kernel-4.4.55.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.
84          */
85         action = desc->action;
86         if (!action || !(action->flags & IRQF_SHARED) ||
87             (action->flags & __IRQF_TIMER))
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                 /* Make sure that there is still a valid action */
106                 action = desc->action;
107         } while ((desc->istate & IRQS_PENDING) && action);
108         desc->istate &= ~IRQS_POLL_INPROGRESS;
109 out:
110         raw_spin_unlock(&desc->lock);
111         return ret == IRQ_HANDLED;
112 }
113
114 static int misrouted_irq(int irq)
115 {
116         struct irq_desc *desc;
117         int i, ok = 0;
118
119         if (atomic_inc_return(&irq_poll_active) != 1)
120                 goto out;
121
122         irq_poll_cpu = smp_processor_id();
123
124         for_each_irq_desc(i, desc) {
125                 if (!i)
126                          continue;
127
128                 if (i == irq)   /* Already tried */
129                         continue;
130
131                 if (try_one_irq(i, desc, false))
132                         ok = 1;
133         }
134 out:
135         atomic_dec(&irq_poll_active);
136         /* So the caller can adjust the irq error counts */
137         return ok;
138 }
139
140 static void poll_spurious_irqs(unsigned long dummy)
141 {
142         struct irq_desc *desc;
143         int i;
144
145         if (atomic_inc_return(&irq_poll_active) != 1)
146                 goto out;
147         irq_poll_cpu = smp_processor_id();
148
149         for_each_irq_desc(i, desc) {
150                 unsigned int state;
151
152                 if (!i)
153                          continue;
154
155                 /* Racy but it doesn't matter */
156                 state = desc->istate;
157                 barrier();
158                 if (!(state & IRQS_SPURIOUS_DISABLED))
159                         continue;
160
161                 local_irq_disable();
162                 try_one_irq(i, desc, true);
163                 local_irq_enable();
164         }
165 out:
166         atomic_dec(&irq_poll_active);
167         mod_timer(&poll_spurious_irq_timer,
168                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
169 }
170
171 static inline int bad_action_ret(irqreturn_t action_ret)
172 {
173         if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
174                 return 0;
175         return 1;
176 }
177
178 /*
179  * If 99,900 of the previous 100,000 interrupts have not been handled
180  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
181  * and try to turn the IRQ off.
182  *
183  * (The other 100-of-100,000 interrupts may have been a correctly
184  *  functioning device sharing an IRQ with the failing one)
185  */
186 static void
187 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
188                  irqreturn_t action_ret)
189 {
190         struct irqaction *action;
191         unsigned long flags;
192
193         if (bad_action_ret(action_ret)) {
194                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
195                                 irq, action_ret);
196         } else {
197                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
198                                 "the \"irqpoll\" option)\n", irq);
199         }
200         dump_stack();
201         printk(KERN_ERR "handlers:\n");
202
203         /*
204          * We need to take desc->lock here. note_interrupt() is called
205          * w/o desc->lock held, but IRQ_PROGRESS set. We might race
206          * with something else removing an action. It's ok to take
207          * desc->lock here. See synchronize_irq().
208          */
209         raw_spin_lock_irqsave(&desc->lock, flags);
210         action = desc->action;
211         while (action) {
212                 printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
213                 if (action->thread_fn)
214                         printk(KERN_CONT " threaded [<%p>] %pf",
215                                         action->thread_fn, action->thread_fn);
216                 printk(KERN_CONT "\n");
217                 action = action->next;
218         }
219         raw_spin_unlock_irqrestore(&desc->lock, flags);
220 }
221
222 static void
223 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
224 {
225         static int count = 100;
226
227         if (count > 0) {
228                 count--;
229                 __report_bad_irq(irq, desc, action_ret);
230         }
231 }
232
233 static inline int
234 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
235                   irqreturn_t action_ret)
236 {
237         struct irqaction *action;
238
239         if (!irqfixup)
240                 return 0;
241
242         /* We didn't actually handle the IRQ - see if it was misrouted? */
243         if (action_ret == IRQ_NONE)
244                 return 1;
245
246         /*
247          * But for 'irqfixup == 2' we also do it for handled interrupts if
248          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
249          * traditional PC timer interrupt.. Legacy)
250          */
251         if (irqfixup < 2)
252                 return 0;
253
254         if (!irq)
255                 return 1;
256
257         /*
258          * Since we don't get the descriptor lock, "action" can
259          * change under us.  We don't really care, but we don't
260          * want to follow a NULL pointer. So tell the compiler to
261          * just load it once by using a barrier.
262          */
263         action = desc->action;
264         barrier();
265         return action && (action->flags & IRQF_IRQPOLL);
266 }
267
268 void note_interrupt(unsigned int irq, struct irq_desc *desc,
269                     irqreturn_t action_ret)
270 {
271         if (desc->istate & IRQS_POLL_INPROGRESS)
272                 return;
273
274         /* we get here again via the threaded handler */
275         if (action_ret == IRQ_WAKE_THREAD)
276                 return;
277
278         if (bad_action_ret(action_ret)) {
279                 report_bad_irq(irq, desc, action_ret);
280                 return;
281         }
282
283         if (unlikely(action_ret == IRQ_NONE)) {
284                 /*
285                  * If we are seeing only the odd spurious IRQ caused by
286                  * bus asynchronicity then don't eventually trigger an error,
287                  * otherwise the counter becomes a doomsday timer for otherwise
288                  * working systems
289                  */
290                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
291                         desc->irqs_unhandled = 1;
292                 else
293                         desc->irqs_unhandled++;
294                 desc->last_unhandled = jiffies;
295         }
296
297         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
298                 int ok = misrouted_irq(irq);
299                 if (action_ret == IRQ_NONE)
300                         desc->irqs_unhandled -= ok;
301         }
302
303         desc->irq_count++;
304         if (likely(desc->irq_count < 100000))
305                 return;
306
307         desc->irq_count = 0;
308         if (unlikely(desc->irqs_unhandled > 99900)) {
309                 /*
310                  * The interrupt is stuck
311                  */
312                 __report_bad_irq(irq, desc, action_ret);
313                 /*
314                  * Now kill the IRQ
315                  */
316                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
317                 desc->istate |= IRQS_SPURIOUS_DISABLED;
318                 desc->depth++;
319                 irq_disable(desc);
320
321                 mod_timer(&poll_spurious_irq_timer,
322                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
323         }
324         desc->irqs_unhandled = 0;
325 }
326
327 bool noirqdebug __read_mostly;
328
329 int noirqdebug_setup(char *str)
330 {
331         noirqdebug = 1;
332         printk(KERN_INFO "IRQ lockup detection disabled\n");
333
334         return 1;
335 }
336
337 __setup("noirqdebug", noirqdebug_setup);
338 module_param(noirqdebug, bool, 0644);
339 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
340
341 static int __init irqfixup_setup(char *str)
342 {
343         irqfixup = 1;
344         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
345         printk(KERN_WARNING "This may impact system performance.\n");
346
347         return 1;
348 }
349
350 __setup("irqfixup", irqfixup_setup);
351 module_param(irqfixup, int, 0644);
352
353 static int __init irqpoll_setup(char *str)
354 {
355         irqfixup = 2;
356         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
357                                 "enabled\n");
358         printk(KERN_WARNING "This may significantly impact system "
359                                 "performance\n");
360         return 1;
361 }
362
363 __setup("irqpoll", irqpoll_setup);