sparc: Allow handling signals when stack is corrupted.
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / irq / spurious.c
blobaa57d5da18c1de65e807098702ad9b841fa3788d
1 /*
2 * linux/kernel/irq/spurious.c
4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
6 * This file contains spurious interrupt handling.
7 */
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>
17 #include "internals.h"
19 static int irqfixup __read_mostly;
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;
28 * We wait here for a poller to finish.
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.
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.
38 bool irq_wait_for_poll(struct irq_desc *desc)
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;
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
61 * Recovery handler for misrouted interrupts.
63 static int try_one_irq(int irq, struct irq_desc *desc, bool force)
65 irqreturn_t ret = IRQ_NONE;
66 struct irqaction *action;
68 raw_spin_lock(&desc->lock);
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;
75 * Do not poll disabled interrupts unless the spurious
76 * disabled poller asks explicitely.
78 if (irqd_irq_disabled(&desc->irq_data) && !force)
79 goto out;
82 * All handlers must agree on IRQF_SHARED, so we test just the
83 * first. Check for action->next as well.
85 action = desc->action;
86 if (!action || !(action->flags & IRQF_SHARED) ||
87 (action->flags & __IRQF_TIMER) || !action->next)
88 goto out;
90 /* Already running on another processor */
91 if (irqd_irq_inprogress(&desc->irq_data)) {
93 * Already running: If it is shared get the other
94 * CPU to go looking for our mystery interrupt too
96 desc->istate |= IRQS_PENDING;
97 goto out;
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;
113 static int misrouted_irq(int irq)
115 struct irq_desc *desc;
116 int i, ok = 0;
118 if (atomic_inc_return(&irq_poll_active) == 1)
119 goto out;
121 irq_poll_cpu = smp_processor_id();
123 for_each_irq_desc(i, desc) {
124 if (!i)
125 continue;
127 if (i == irq) /* Already tried */
128 continue;
130 if (try_one_irq(i, desc, false))
131 ok = 1;
133 out:
134 atomic_dec(&irq_poll_active);
135 /* So the caller can adjust the irq error counts */
136 return ok;
139 static void poll_spurious_irqs(unsigned long dummy)
141 struct irq_desc *desc;
142 int i;
144 if (atomic_inc_return(&irq_poll_active) != 1)
145 goto out;
146 irq_poll_cpu = smp_processor_id();
148 for_each_irq_desc(i, desc) {
149 unsigned int state;
151 if (!i)
152 continue;
154 /* Racy but it doesn't matter */
155 state = desc->istate;
156 barrier();
157 if (!(state & IRQS_SPURIOUS_DISABLED))
158 continue;
160 local_irq_disable();
161 try_one_irq(i, desc, true);
162 local_irq_enable();
164 out:
165 atomic_dec(&irq_poll_active);
166 mod_timer(&poll_spurious_irq_timer,
167 jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
170 static inline int bad_action_ret(irqreturn_t action_ret)
172 if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
173 return 0;
174 return 1;
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.
182 * (The other 100-of-100,000 interrupts may have been a correctly
183 * functioning device sharing an IRQ with the failing one)
185 static void
186 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
187 irqreturn_t action_ret)
189 struct irqaction *action;
190 unsigned long flags;
192 if (bad_action_ret(action_ret)) {
193 printk(KERN_ERR "irq event %d: bogus return value %x\n",
194 irq, action_ret);
195 } else {
196 printk(KERN_ERR "irq %d: nobody cared (try booting with "
197 "the \"irqpoll\" option)\n", irq);
199 dump_stack();
200 printk(KERN_ERR "handlers:\n");
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().
208 raw_spin_lock_irqsave(&desc->lock, flags);
209 action = desc->action;
210 while (action) {
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");
216 action = action->next;
218 raw_spin_unlock_irqrestore(&desc->lock, flags);
221 static void
222 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
224 static int count = 100;
226 if (count > 0) {
227 count--;
228 __report_bad_irq(irq, desc, action_ret);
232 static inline int
233 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
234 irqreturn_t action_ret)
236 struct irqaction *action;
238 if (!irqfixup)
239 return 0;
241 /* We didn't actually handle the IRQ - see if it was misrouted? */
242 if (action_ret == IRQ_NONE)
243 return 1;
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)
250 if (irqfixup < 2)
251 return 0;
253 if (!irq)
254 return 1;
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.
262 action = desc->action;
263 barrier();
264 return action && (action->flags & IRQF_IRQPOLL);
267 void note_interrupt(unsigned int irq, struct irq_desc *desc,
268 irqreturn_t action_ret)
270 if (desc->istate & IRQS_POLL_INPROGRESS)
271 return;
273 /* we get here again via the threaded handler */
274 if (action_ret == IRQ_WAKE_THREAD)
275 return;
277 if (bad_action_ret(action_ret)) {
278 report_bad_irq(irq, desc, action_ret);
279 return;
282 if (unlikely(action_ret == IRQ_NONE)) {
284 * If we are seeing only the odd spurious IRQ caused by
285 * bus asynchronicity then don't eventually trigger an error,
286 * otherwise the counter becomes a doomsday timer for otherwise
287 * working systems
289 if (time_after(jiffies, desc->last_unhandled + HZ/10))
290 desc->irqs_unhandled = 1;
291 else
292 desc->irqs_unhandled++;
293 desc->last_unhandled = jiffies;
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;
302 desc->irq_count++;
303 if (likely(desc->irq_count < 100000))
304 return;
306 desc->irq_count = 0;
307 if (unlikely(desc->irqs_unhandled > 99900)) {
309 * The interrupt is stuck
311 __report_bad_irq(irq, desc, action_ret);
313 * Now kill the IRQ
315 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
316 desc->istate |= IRQS_SPURIOUS_DISABLED;
317 desc->depth++;
318 irq_disable(desc);
320 mod_timer(&poll_spurious_irq_timer,
321 jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
323 desc->irqs_unhandled = 0;
326 int noirqdebug __read_mostly;
328 int noirqdebug_setup(char *str)
330 noirqdebug = 1;
331 printk(KERN_INFO "IRQ lockup detection disabled\n");
333 return 1;
336 __setup("noirqdebug", noirqdebug_setup);
337 module_param(noirqdebug, bool, 0644);
338 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
340 static int __init irqfixup_setup(char *str)
342 irqfixup = 1;
343 printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
344 printk(KERN_WARNING "This may impact system performance.\n");
346 return 1;
349 __setup("irqfixup", irqfixup_setup);
350 module_param(irqfixup, int, 0644);
352 static int __init irqpoll_setup(char *str)
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;
362 __setup("irqpoll", irqpoll_setup);