umh: creds: convert call_usermodehelper_keys() to use subprocess_info->init()
[linux-2.6.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 static int irqfixup __read_mostly;
18
19 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
20 static void poll_spurious_irqs(unsigned long dummy);
21 static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
22
23 /*
24  * Recovery handler for misrouted interrupts.
25  */
26 static int try_one_irq(int irq, struct irq_desc *desc)
27 {
28         struct irqaction *action;
29         int ok = 0, work = 0;
30
31         raw_spin_lock(&desc->lock);
32         /* Already running on another processor */
33         if (desc->status & IRQ_INPROGRESS) {
34                 /*
35                  * Already running: If it is shared get the other
36                  * CPU to go looking for our mystery interrupt too
37                  */
38                 if (desc->action && (desc->action->flags & IRQF_SHARED))
39                         desc->status |= IRQ_PENDING;
40                 raw_spin_unlock(&desc->lock);
41                 return ok;
42         }
43         /* Honour the normal IRQ locking */
44         desc->status |= IRQ_INPROGRESS;
45         action = desc->action;
46         raw_spin_unlock(&desc->lock);
47
48         while (action) {
49                 /* Only shared IRQ handlers are safe to call */
50                 if (action->flags & IRQF_SHARED) {
51                         if (action->handler(irq, action->dev_id) ==
52                                 IRQ_HANDLED)
53                                 ok = 1;
54                 }
55                 action = action->next;
56         }
57         local_irq_disable();
58         /* Now clean up the flags */
59         raw_spin_lock(&desc->lock);
60         action = desc->action;
61
62         /*
63          * While we were looking for a fixup someone queued a real
64          * IRQ clashing with our walk:
65          */
66         while ((desc->status & IRQ_PENDING) && action) {
67                 /*
68                  * Perform real IRQ processing for the IRQ we deferred
69                  */
70                 work = 1;
71                 raw_spin_unlock(&desc->lock);
72                 handle_IRQ_event(irq, action);
73                 raw_spin_lock(&desc->lock);
74                 desc->status &= ~IRQ_PENDING;
75         }
76         desc->status &= ~IRQ_INPROGRESS;
77         /*
78          * If we did actual work for the real IRQ line we must let the
79          * IRQ controller clean up too
80          */
81         if (work && desc->chip && desc->chip->end)
82                 desc->chip->end(irq);
83         raw_spin_unlock(&desc->lock);
84
85         return ok;
86 }
87
88 static int misrouted_irq(int irq)
89 {
90         struct irq_desc *desc;
91         int i, ok = 0;
92
93         for_each_irq_desc(i, desc) {
94                 if (!i)
95                          continue;
96
97                 if (i == irq)   /* Already tried */
98                         continue;
99
100                 if (try_one_irq(i, desc))
101                         ok = 1;
102         }
103         /* So the caller can adjust the irq error counts */
104         return ok;
105 }
106
107 static void poll_spurious_irqs(unsigned long dummy)
108 {
109         struct irq_desc *desc;
110         int i;
111
112         for_each_irq_desc(i, desc) {
113                 unsigned int status;
114
115                 if (!i)
116                          continue;
117
118                 /* Racy but it doesn't matter */
119                 status = desc->status;
120                 barrier();
121                 if (!(status & IRQ_SPURIOUS_DISABLED))
122                         continue;
123
124                 local_irq_disable();
125                 try_one_irq(i, desc);
126                 local_irq_enable();
127         }
128
129         mod_timer(&poll_spurious_irq_timer,
130                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
131 }
132
133 /*
134  * If 99,900 of the previous 100,000 interrupts have not been handled
135  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
136  * and try to turn the IRQ off.
137  *
138  * (The other 100-of-100,000 interrupts may have been a correctly
139  *  functioning device sharing an IRQ with the failing one)
140  *
141  * Called under desc->lock
142  */
143
144 static void
145 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
146                  irqreturn_t action_ret)
147 {
148         struct irqaction *action;
149
150         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
151                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
152                                 irq, action_ret);
153         } else {
154                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
155                                 "the \"irqpoll\" option)\n", irq);
156         }
157         dump_stack();
158         printk(KERN_ERR "handlers:\n");
159
160         action = desc->action;
161         while (action) {
162                 printk(KERN_ERR "[<%p>]", action->handler);
163                 print_symbol(" (%s)",
164                         (unsigned long)action->handler);
165                 printk("\n");
166                 action = action->next;
167         }
168 }
169
170 static void
171 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
172 {
173         static int count = 100;
174
175         if (count > 0) {
176                 count--;
177                 __report_bad_irq(irq, desc, action_ret);
178         }
179 }
180
181 static inline int
182 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
183                   irqreturn_t action_ret)
184 {
185         struct irqaction *action;
186
187         if (!irqfixup)
188                 return 0;
189
190         /* We didn't actually handle the IRQ - see if it was misrouted? */
191         if (action_ret == IRQ_NONE)
192                 return 1;
193
194         /*
195          * But for 'irqfixup == 2' we also do it for handled interrupts if
196          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
197          * traditional PC timer interrupt.. Legacy)
198          */
199         if (irqfixup < 2)
200                 return 0;
201
202         if (!irq)
203                 return 1;
204
205         /*
206          * Since we don't get the descriptor lock, "action" can
207          * change under us.  We don't really care, but we don't
208          * want to follow a NULL pointer. So tell the compiler to
209          * just load it once by using a barrier.
210          */
211         action = desc->action;
212         barrier();
213         return action && (action->flags & IRQF_IRQPOLL);
214 }
215
216 void note_interrupt(unsigned int irq, struct irq_desc *desc,
217                     irqreturn_t action_ret)
218 {
219         if (unlikely(action_ret != IRQ_HANDLED)) {
220                 /*
221                  * If we are seeing only the odd spurious IRQ caused by
222                  * bus asynchronicity then don't eventually trigger an error,
223                  * otherwise the counter becomes a doomsday timer for otherwise
224                  * working systems
225                  */
226                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
227                         desc->irqs_unhandled = 1;
228                 else
229                         desc->irqs_unhandled++;
230                 desc->last_unhandled = jiffies;
231                 if (unlikely(action_ret != IRQ_NONE))
232                         report_bad_irq(irq, desc, action_ret);
233         }
234
235         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
236                 int ok = misrouted_irq(irq);
237                 if (action_ret == IRQ_NONE)
238                         desc->irqs_unhandled -= ok;
239         }
240
241         desc->irq_count++;
242         if (likely(desc->irq_count < 100000))
243                 return;
244
245         desc->irq_count = 0;
246         if (unlikely(desc->irqs_unhandled > 99900)) {
247                 /*
248                  * The interrupt is stuck
249                  */
250                 __report_bad_irq(irq, desc, action_ret);
251                 /*
252                  * Now kill the IRQ
253                  */
254                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
255                 desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
256                 desc->depth++;
257                 desc->chip->disable(irq);
258
259                 mod_timer(&poll_spurious_irq_timer,
260                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
261         }
262         desc->irqs_unhandled = 0;
263 }
264
265 int noirqdebug __read_mostly;
266
267 int noirqdebug_setup(char *str)
268 {
269         noirqdebug = 1;
270         printk(KERN_INFO "IRQ lockup detection disabled\n");
271
272         return 1;
273 }
274
275 __setup("noirqdebug", noirqdebug_setup);
276 module_param(noirqdebug, bool, 0644);
277 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
278
279 static int __init irqfixup_setup(char *str)
280 {
281         irqfixup = 1;
282         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
283         printk(KERN_WARNING "This may impact system performance.\n");
284
285         return 1;
286 }
287
288 __setup("irqfixup", irqfixup_setup);
289 module_param(irqfixup, int, 0644);
290
291 static int __init irqpoll_setup(char *str)
292 {
293         irqfixup = 2;
294         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
295                                 "enabled\n");
296         printk(KERN_WARNING "This may significantly impact system "
297                                 "performance\n");
298         return 1;
299 }
300
301 __setup("irqpoll", irqpoll_setup);