summaryrefslogtreecommitdiffstats
path: root/kernel/irq/spurious.c
blob: 2fbfda2716e1253c33aeef02037766723f789760 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
/*
 * linux/kernel/irq/spurious.c
 *
 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
 *
 * This file contains spurious interrupt handling.
 */

#include <linux/jiffies.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
#include <linux/timer.h>

#include "internals.h"

static int irqfixup __read_mostly;

#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
static void poll_spurious_irqs(unsigned long dummy);
static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);

/*
 * Recovery handler for misrouted interrupts.
 */
static int try_one_irq(int irq, struct irq_desc *desc)
{
	struct irqaction *action;
	int ok = 0, work = 0;

	raw_spin_lock(&desc->lock);
	/* Already running on another processor */
	if (desc->status & IRQ_INPROGRESS) {
		/*
		 * Already running: If it is shared get the other
		 * CPU to go looking for our mystery interrupt too
		 */
		if (desc->action && (desc->action->flags & IRQF_SHARED))
			desc->status |= IRQ_PENDING;
		raw_spin_unlock(&desc->lock);
		return ok;
	}
	/* Honour the normal IRQ locking */
	desc->status |= IRQ_INPROGRESS;
	action = desc->action;
	raw_spin_unlock(&desc->lock);

	while (action) {
		/* Only shared IRQ handlers are safe to call */
		if (action->flags & IRQF_SHARED) {
			if (action->handler(irq, action->dev_id) ==
				IRQ_HANDLED)
				ok = 1;
		}
		action = action->next;
	}
	local_irq_disable();
	/* Now clean up the flags */
	raw_spin_lock(&desc->lock);
	action = desc->action;

	/*
	 * While we were looking for a fixup someone queued a real
	 * IRQ clashing with our walk:
	 */
	while ((desc->status & IRQ_PENDING) && action) {
		/*
		 * Perform real IRQ processing for the IRQ we deferred
		 */
		work = 1;
		raw_spin_unlock(&desc->lock);
		handle_IRQ_event(irq, action);
		raw_spin_lock(&desc->lock);
		desc->status &= ~IRQ_PENDING;
	}
	desc->status &= ~IRQ_INPROGRESS;
	/*
	 * If we did actual work for the real IRQ line we must let the
	 * IRQ controller clean up too
	 */
	if (work)
		irq_end(irq, desc);
	raw_spin_unlock(&desc->lock);

	return ok;
}

static int misrouted_irq(int irq)
{
	struct irq_desc *desc;
	int i, ok = 0;

	for_each_irq_desc(i, desc) {
		if (!i)
			 continue;

		if (i == irq)	/* Already tried */
			continue;

		if (try_one_irq(i, desc))
			ok = 1;
	}
	/* So the caller can adjust the irq error counts */
	return ok;
}

static void poll_spurious_irqs(unsigned long dummy)
{
	struct irq_desc *desc;
	int i;

	for_each_irq_desc(i, desc) {
		unsigned int status;

		if (!i)
			 continue;

		/* Racy but it doesn't matter */
		status = desc->status;
		barrier();
		if (!(status & IRQ_SPURIOUS_DISABLED))
			continue;

		local_irq_disable();
		try_one_irq(i, desc);
		local_irq_enable();
	}

	mod_timer(&poll_spurious_irq_timer,
		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
}

/*
 * If 99,900 of the previous 100,000 interrupts have not been handled
 * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 * and try to turn the IRQ off.
 *
 * (The other 100-of-100,000 interrupts may have been a correctly
 *  functioning device sharing an IRQ with the failing one)
 */
static void
__report_bad_irq(unsigned int irq, struct irq_desc *desc,
		 irqreturn_t action_ret)
{
	struct irqaction *action;
	unsigned long flags;

	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
		printk(KERN_ERR "irq event %d: bogus return value %x\n",
				irq, action_ret);
	} else {
		printk(KERN_ERR "irq %d: nobody cared (try booting with "
				"the \"irqpoll\" option)\n", irq);
	}
	dump_stack();
	printk(KERN_ERR "handlers:\n");

	/*
	 * We need to take desc->lock here. note_interrupt() is called
	 * w/o desc->lock held, but IRQ_PROGRESS set. We might race
	 * with something else removing an action. It's ok to take
	 * desc->lock here. See synchronize_irq().
	 */
	raw_spin_lock_irqsave(&desc->lock, flags);
	action = desc->action;
	while (action) {
		printk(KERN_ERR "[<%p>]", action->handler);
		print_symbol(" (%s)",
			(unsigned long)action->handler);
		printk("\n");
		action = action->next;
	}
	raw_spin_unlock_irqrestore(&desc->lock, flags);
}

static void
report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
{
	static int count = 100;

	if (count > 0) {
		count--;
		__report_bad_irq(irq, desc, action_ret);
	}
}

static inline int
try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
		  irqreturn_t action_ret)
{
	struct irqaction *action;

	if (!irqfixup)
		return 0;

	/* We didn't actually handle the IRQ - see if it was misrouted? */
	if (action_ret == IRQ_NONE)
		return 1;

	/*
	 * But for 'irqfixup == 2' we also do it for handled interrupts if
	 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	 * traditional PC timer interrupt.. Legacy)
	 */
	if (irqfixup < 2)
		return 0;

	if (!irq)
		return 1;

	/*
	 * Since we don't get the descriptor lock, "action" can
	 * change under us.  We don't really care, but we don't
	 * want to follow a NULL pointer. So tell the compiler to
	 * just load it once by using a barrier.
	 */
	action = desc->action;
	barrier();
	return action && (action->flags & IRQF_IRQPOLL);
}

void note_interrupt(unsigned int irq, struct irq_desc *desc,
		    irqreturn_t action_ret)
{
	if (unlikely(action_ret != IRQ_HANDLED)) {
		/*
		 * If we are seeing only the odd spurious IRQ caused by
		 * bus asynchronicity then don't eventually trigger an error,
		 * otherwise the counter becomes a doomsday timer for otherwise
		 * working systems
		 */
		if (time_after(jiffies, desc->last_unhandled + HZ/10))
			desc->irqs_unhandled = 1;
		else
			desc->irqs_unhandled++;
		desc->last_unhandled = jiffies;
		if (unlikely(action_ret != IRQ_NONE))
			report_bad_irq(irq, desc, action_ret);
	}

	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
		int ok = misrouted_irq(irq);
		if (action_ret == IRQ_NONE)
			desc->irqs_unhandled -= ok;
	}

	desc->irq_count++;
	if (likely(desc->irq_count < 100000))
		return;

	desc->irq_count = 0;
	if (unlikely(desc->irqs_unhandled > 99900)) {
		/*
		 * The interrupt is stuck
		 */
		__report_bad_irq(irq, desc, action_ret);
		/*
		 * Now kill the IRQ
		 */
		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
		desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
		desc->depth++;
		desc->irq_data.chip->irq_disable(&desc->irq_data);

		mod_timer(&poll_spurious_irq_timer,
			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
	}
	desc->irqs_unhandled = 0;
}

int noirqdebug __read_mostly;

int noirqdebug_setup(char *str)
{
	noirqdebug = 1;
	printk(KERN_INFO "IRQ lockup detection disabled\n");

	return 1;
}

__setup("noirqdebug", noirqdebug_setup);
module_param(noirqdebug, bool, 0644);
MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");

static int __init irqfixup_setup(char *str)
{
	irqfixup = 1;
	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	printk(KERN_WARNING "This may impact system performance.\n");

	return 1;
}

__setup("irqfixup", irqfixup_setup);
module_param(irqfixup, int, 0644);

static int __init irqpoll_setup(char *str)
{
	irqfixup = 2;
	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
				"enabled\n");
	printk(KERN_WARNING "This may significantly impact system "
				"performance\n");
	return 1;
}

__setup("irqpoll", irqpoll_setup);
OpenPOWER on IntegriCloud