Merge branch 'stable/bug.fixes' of git://oss.oracle.com/git/kwilk/xen
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / irq / spurious.c
CommitLineData
1da177e4
LT
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
188fd89d 9#include <linux/jiffies.h>
1da177e4
LT
10#include <linux/irq.h>
11#include <linux/module.h>
12#include <linux/kallsyms.h>
13#include <linux/interrupt.h>
9e094c17 14#include <linux/moduleparam.h>
f84dbb91 15#include <linux/timer.h>
1da177e4 16
bd151412
TG
17#include "internals.h"
18
83d4e6e7 19static int irqfixup __read_mostly;
200803df 20
f84dbb91
EB
21#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
22static void poll_spurious_irqs(unsigned long dummy);
23static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
d05c65ff
TG
24static int irq_poll_cpu;
25static atomic_t irq_poll_active;
f84dbb91 26
fe200ae4
TG
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 */
38bool 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);
32f4125e 48 while (irqd_irq_inprogress(&desc->irq_data))
fe200ae4
TG
49 cpu_relax();
50 raw_spin_lock(&desc->lock);
a6aeddd1 51 } while (irqd_irq_inprogress(&desc->irq_data));
fe200ae4 52 /* Might have been disabled in meantime */
32f4125e 53 return !irqd_irq_disabled(&desc->irq_data) && desc->action;
fe200ae4
TG
54#else
55 return false;
56#endif
57}
58
0877d662 59
200803df
AC
60/*
61 * Recovery handler for misrouted interrupts.
62 */
c7259cd7 63static int try_one_irq(int irq, struct irq_desc *desc, bool force)
200803df 64{
0877d662 65 irqreturn_t ret = IRQ_NONE;
f84dbb91 66 struct irqaction *action;
200803df 67
239007b8 68 raw_spin_lock(&desc->lock);
c7259cd7
TG
69
70 /* PER_CPU and nested thread interrupts are never polled */
1ccb4e61 71 if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc))
c7259cd7
TG
72 goto out;
73
74 /*
75 * Do not poll disabled interrupts unless the spurious
76 * disabled poller asks explicitely.
77 */
32f4125e 78 if (irqd_irq_disabled(&desc->irq_data) && !force)
c7259cd7
TG
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
f84dbb91 90 /* Already running on another processor */
32f4125e 91 if (irqd_irq_inprogress(&desc->irq_data)) {
f84dbb91
EB
92 /*
93 * Already running: If it is shared get the other
94 * CPU to go looking for our mystery interrupt too
95 */
2a0d6fb3 96 desc->istate |= IRQS_PENDING;
fa27271b 97 goto out;
c7259cd7 98 }
fa27271b 99
0877d662 100 /* Mark it poll in progress */
6954b75b 101 desc->istate |= IRQS_POLL_INPROGRESS;
fa27271b 102 do {
0877d662
TG
103 if (handle_irq_event(desc) == IRQ_HANDLED)
104 ret = IRQ_HANDLED;
fa27271b 105 action = desc->action;
2a0d6fb3 106 } while ((desc->istate & IRQS_PENDING) && action);
6954b75b 107 desc->istate &= ~IRQS_POLL_INPROGRESS;
fa27271b
TG
108out:
109 raw_spin_unlock(&desc->lock);
0877d662 110 return ret == IRQ_HANDLED;
f84dbb91
EB
111}
112
113static int misrouted_irq(int irq)
114{
e00585bb 115 struct irq_desc *desc;
d3c60047 116 int i, ok = 0;
f84dbb91 117
d05c65ff
TG
118 if (atomic_inc_return(&irq_poll_active) == 1)
119 goto out;
120
121 irq_poll_cpu = smp_processor_id();
122
e00585bb
YL
123 for_each_irq_desc(i, desc) {
124 if (!i)
125 continue;
f84dbb91
EB
126
127 if (i == irq) /* Already tried */
128 continue;
129
c7259cd7 130 if (try_one_irq(i, desc, false))
f84dbb91 131 ok = 1;
200803df 132 }
d05c65ff
TG
133out:
134 atomic_dec(&irq_poll_active);
200803df
AC
135 /* So the caller can adjust the irq error counts */
136 return ok;
137}
138
663e6959 139static void poll_spurious_irqs(unsigned long dummy)
f84dbb91 140{
e00585bb 141 struct irq_desc *desc;
d3c60047 142 int i;
e00585bb 143
d05c65ff
TG
144 if (atomic_inc_return(&irq_poll_active) != 1)
145 goto out;
146 irq_poll_cpu = smp_processor_id();
147
e00585bb 148 for_each_irq_desc(i, desc) {
7acdd53e 149 unsigned int state;
f84dbb91 150
e00585bb
YL
151 if (!i)
152 continue;
153
f84dbb91 154 /* Racy but it doesn't matter */
7acdd53e 155 state = desc->istate;
f84dbb91 156 barrier();
7acdd53e 157 if (!(state & IRQS_SPURIOUS_DISABLED))
f84dbb91
EB
158 continue;
159
e7e7e0c0 160 local_irq_disable();
c7259cd7 161 try_one_irq(i, desc, true);
e7e7e0c0 162 local_irq_enable();
f84dbb91 163 }
d05c65ff
TG
164out:
165 atomic_dec(&irq_poll_active);
d3c60047
TG
166 mod_timer(&poll_spurious_irq_timer,
167 jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
f84dbb91
EB
168}
169
3a43e05f
SAS
170static inline int bad_action_ret(irqreturn_t action_ret)
171{
172 if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
173 return 0;
174 return 1;
175}
176
1da177e4
LT
177/*
178 * If 99,900 of the previous 100,000 interrupts have not been handled
179 * then assume that the IRQ is stuck in some manner. Drop a diagnostic
180 * and try to turn the IRQ off.
181 *
182 * (The other 100-of-100,000 interrupts may have been a correctly
183 * functioning device sharing an IRQ with the failing one)
1da177e4 184 */
1da177e4 185static void
34ffdb72
IM
186__report_bad_irq(unsigned int irq, struct irq_desc *desc,
187 irqreturn_t action_ret)
1da177e4
LT
188{
189 struct irqaction *action;
1082687e 190 unsigned long flags;
1da177e4 191
3a43e05f 192 if (bad_action_ret(action_ret)) {
1da177e4
LT
193 printk(KERN_ERR "irq event %d: bogus return value %x\n",
194 irq, action_ret);
195 } else {
200803df
AC
196 printk(KERN_ERR "irq %d: nobody cared (try booting with "
197 "the \"irqpoll\" option)\n", irq);
1da177e4
LT
198 }
199 dump_stack();
200 printk(KERN_ERR "handlers:\n");
06fcb0c6 201
1082687e
TG
202 /*
203 * We need to take desc->lock here. note_interrupt() is called
204 * w/o desc->lock held, but IRQ_PROGRESS set. We might race
205 * with something else removing an action. It's ok to take
206 * desc->lock here. See synchronize_irq().
207 */
208 raw_spin_lock_irqsave(&desc->lock, flags);
1da177e4
LT
209 action = desc->action;
210 while (action) {
ef26f20c
SAS
211 printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
212 if (action->thread_fn)
213 printk(KERN_CONT " threaded [<%p>] %pf",
214 action->thread_fn, action->thread_fn);
215 printk(KERN_CONT "\n");
1da177e4
LT
216 action = action->next;
217 }
1082687e 218 raw_spin_unlock_irqrestore(&desc->lock, flags);
1da177e4
LT
219}
220
06fcb0c6 221static void
34ffdb72 222report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
1da177e4
LT
223{
224 static int count = 100;
225
226 if (count > 0) {
227 count--;
228 __report_bad_irq(irq, desc, action_ret);
229 }
230}
231
d3c60047
TG
232static inline int
233try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
234 irqreturn_t action_ret)
92ea7727
LT
235{
236 struct irqaction *action;
237
238 if (!irqfixup)
239 return 0;
240
241 /* We didn't actually handle the IRQ - see if it was misrouted? */
242 if (action_ret == IRQ_NONE)
243 return 1;
244
245 /*
246 * But for 'irqfixup == 2' we also do it for handled interrupts if
247 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
248 * traditional PC timer interrupt.. Legacy)
249 */
250 if (irqfixup < 2)
251 return 0;
252
253 if (!irq)
254 return 1;
255
256 /*
257 * Since we don't get the descriptor lock, "action" can
258 * change under us. We don't really care, but we don't
259 * want to follow a NULL pointer. So tell the compiler to
260 * just load it once by using a barrier.
261 */
262 action = desc->action;
263 barrier();
264 return action && (action->flags & IRQF_IRQPOLL);
265}
266
34ffdb72 267void note_interrupt(unsigned int irq, struct irq_desc *desc,
7d12e780 268 irqreturn_t action_ret)
1da177e4 269{
6954b75b 270 if (desc->istate & IRQS_POLL_INPROGRESS)
fe200ae4
TG
271 return;
272
3a43e05f
SAS
273 /* we get here again via the threaded handler */
274 if (action_ret == IRQ_WAKE_THREAD)
275 return;
276
277 if (bad_action_ret(action_ret)) {
278 report_bad_irq(irq, desc, action_ret);
279 return;
280 }
281
282 if (unlikely(action_ret == IRQ_NONE)) {
4f27c00b
AC
283 /*
284 * If we are seeing only the odd spurious IRQ caused by
285 * bus asynchronicity then don't eventually trigger an error,
fbfecd37 286 * otherwise the counter becomes a doomsday timer for otherwise
4f27c00b
AC
287 * working systems
288 */
188fd89d 289 if (time_after(jiffies, desc->last_unhandled + HZ/10))
4f27c00b
AC
290 desc->irqs_unhandled = 1;
291 else
292 desc->irqs_unhandled++;
293 desc->last_unhandled = jiffies;
1da177e4
LT
294 }
295
92ea7727
LT
296 if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
297 int ok = misrouted_irq(irq);
298 if (action_ret == IRQ_NONE)
299 desc->irqs_unhandled -= ok;
200803df
AC
300 }
301
1da177e4 302 desc->irq_count++;
83d4e6e7 303 if (likely(desc->irq_count < 100000))
1da177e4
LT
304 return;
305
306 desc->irq_count = 0;
83d4e6e7 307 if (unlikely(desc->irqs_unhandled > 99900)) {
1da177e4
LT
308 /*
309 * The interrupt is stuck
310 */
311 __report_bad_irq(irq, desc, action_ret);
312 /*
313 * Now kill the IRQ
314 */
315 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
7acdd53e 316 desc->istate |= IRQS_SPURIOUS_DISABLED;
1adb0850 317 desc->depth++;
87923470 318 irq_disable(desc);
f84dbb91 319
d3c60047
TG
320 mod_timer(&poll_spurious_irq_timer,
321 jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
1da177e4
LT
322 }
323 desc->irqs_unhandled = 0;
324}
325
83d4e6e7 326int noirqdebug __read_mostly;
1da177e4 327
343cde51 328int noirqdebug_setup(char *str)
1da177e4
LT
329{
330 noirqdebug = 1;
331 printk(KERN_INFO "IRQ lockup detection disabled\n");
06fcb0c6 332
1da177e4
LT
333 return 1;
334}
335
336__setup("noirqdebug", noirqdebug_setup);
9e094c17
AK
337module_param(noirqdebug, bool, 0644);
338MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
1da177e4 339
200803df
AC
340static int __init irqfixup_setup(char *str)
341{
342 irqfixup = 1;
343 printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
344 printk(KERN_WARNING "This may impact system performance.\n");
06fcb0c6 345
200803df
AC
346 return 1;
347}
348
349__setup("irqfixup", irqfixup_setup);
9e094c17 350module_param(irqfixup, int, 0644);
200803df
AC
351
352static int __init irqpoll_setup(char *str)
353{
354 irqfixup = 2;
355 printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
356 "enabled\n");
357 printk(KERN_WARNING "This may significantly impact system "
358 "performance\n");
359 return 1;
360}
361
362__setup("irqpoll", irqpoll_setup);