Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial
[linux-2.6] / 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/irq.h>
10 #include <linux/module.h>
11 #include <linux/kallsyms.h>
12 #include <linux/interrupt.h>
13
14 static int irqfixup;
15
16 /*
17  * Recovery handler for misrouted interrupts.
18  */
19
20 static int misrouted_irq(int irq, struct pt_regs *regs)
21 {
22         int i;
23         irq_desc_t *desc;
24         int ok = 0;
25         int work = 0;   /* Did we do work for a real IRQ */
26
27         for(i = 1; i < NR_IRQS; i++) {
28                 struct irqaction *action;
29
30                 if (i == irq)   /* Already tried */
31                         continue;
32                 desc = &irq_desc[i];
33                 spin_lock(&desc->lock);
34                 action = desc->action;
35                 /* Already running on another processor */
36                 if (desc->status & IRQ_INPROGRESS) {
37                         /*
38                          * Already running: If it is shared get the other
39                          * CPU to go looking for our mystery interrupt too
40                          */
41                         if (desc->action && (desc->action->flags & SA_SHIRQ))
42                                 desc->status |= IRQ_PENDING;
43                         spin_unlock(&desc->lock);
44                         continue;
45                 }
46                 /* Honour the normal IRQ locking */
47                 desc->status |= IRQ_INPROGRESS;
48                 spin_unlock(&desc->lock);
49                 while (action) {
50                         /* Only shared IRQ handlers are safe to call */
51                         if (action->flags & SA_SHIRQ) {
52                                 if (action->handler(i, action->dev_id, regs) ==
53                                                 IRQ_HANDLED)
54                                         ok = 1;
55                         }
56                         action = action->next;
57                 }
58                 local_irq_disable();
59                 /* Now clean up the flags */
60                 spin_lock(&desc->lock);
61                 action = desc->action;
62
63                 /*
64                  * While we were looking for a fixup someone queued a real
65                  * IRQ clashing with our walk
66                  */
67
68                 while ((desc->status & IRQ_PENDING) && action) {
69                         /*
70                          * Perform real IRQ processing for the IRQ we deferred
71                          */
72                         work = 1;
73                         spin_unlock(&desc->lock);
74                         handle_IRQ_event(i, regs, action);
75                         spin_lock(&desc->lock);
76                         desc->status &= ~IRQ_PENDING;
77                 }
78                 desc->status &= ~IRQ_INPROGRESS;
79                 /*
80                  * If we did actual work for the real IRQ line we must let the
81                  * IRQ controller clean up too
82                  */
83                 if(work)
84                         desc->handler->end(i);
85                 spin_unlock(&desc->lock);
86         }
87         /* So the caller can adjust the irq error counts */
88         return ok;
89 }
90
91 /*
92  * If 99,900 of the previous 100,000 interrupts have not been handled
93  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
94  * and try to turn the IRQ off.
95  *
96  * (The other 100-of-100,000 interrupts may have been a correctly
97  *  functioning device sharing an IRQ with the failing one)
98  *
99  * Called under desc->lock
100  */
101
102 static void
103 __report_bad_irq(unsigned int irq, irq_desc_t *desc, irqreturn_t action_ret)
104 {
105         struct irqaction *action;
106
107         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
108                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
109                                 irq, action_ret);
110         } else {
111                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
112                                 "the \"irqpoll\" option)\n", irq);
113         }
114         dump_stack();
115         printk(KERN_ERR "handlers:\n");
116         action = desc->action;
117         while (action) {
118                 printk(KERN_ERR "[<%p>]", action->handler);
119                 print_symbol(" (%s)",
120                         (unsigned long)action->handler);
121                 printk("\n");
122                 action = action->next;
123         }
124 }
125
126 static void report_bad_irq(unsigned int irq, irq_desc_t *desc, irqreturn_t action_ret)
127 {
128         static int count = 100;
129
130         if (count > 0) {
131                 count--;
132                 __report_bad_irq(irq, desc, action_ret);
133         }
134 }
135
136 void note_interrupt(unsigned int irq, irq_desc_t *desc, irqreturn_t action_ret,
137                         struct pt_regs *regs)
138 {
139         if (action_ret != IRQ_HANDLED) {
140                 desc->irqs_unhandled++;
141                 if (action_ret != IRQ_NONE)
142                         report_bad_irq(irq, desc, action_ret);
143         }
144
145         if (unlikely(irqfixup)) {
146                 /* Don't punish working computers */
147                 if ((irqfixup == 2 && irq == 0) || action_ret == IRQ_NONE) {
148                         int ok = misrouted_irq(irq, regs);
149                         if (action_ret == IRQ_NONE)
150                                 desc->irqs_unhandled -= ok;
151                 }
152         }
153
154         desc->irq_count++;
155         if (desc->irq_count < 100000)
156                 return;
157
158         desc->irq_count = 0;
159         if (desc->irqs_unhandled > 99900) {
160                 /*
161                  * The interrupt is stuck
162                  */
163                 __report_bad_irq(irq, desc, action_ret);
164                 /*
165                  * Now kill the IRQ
166                  */
167                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
168                 desc->status |= IRQ_DISABLED;
169                 desc->handler->disable(irq);
170         }
171         desc->irqs_unhandled = 0;
172 }
173
174 int noirqdebug;
175
176 int __init noirqdebug_setup(char *str)
177 {
178         noirqdebug = 1;
179         printk(KERN_INFO "IRQ lockup detection disabled\n");
180         return 1;
181 }
182
183 __setup("noirqdebug", noirqdebug_setup);
184
185 static int __init irqfixup_setup(char *str)
186 {
187         irqfixup = 1;
188         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
189         printk(KERN_WARNING "This may impact system performance.\n");
190         return 1;
191 }
192
193 __setup("irqfixup", irqfixup_setup);
194
195 static int __init irqpoll_setup(char *str)
196 {
197         irqfixup = 2;
198         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
199                                 "enabled\n");
200         printk(KERN_WARNING "This may significantly impact system "
201                                 "performance\n");
202         return 1;
203 }
204
205 __setup("irqpoll", irqpoll_setup);