summaryrefslogtreecommitdiffstats
path: root/kernel/irq/proc.c
blob: d2c0e5ee53c573019f45942e4d63bb362db42551 (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
/*
 * linux/kernel/irq/proc.c
 *
 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
 *
 * This file contains the /proc/irq/ handling code.
 */

#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>

#include "internals.h"

static struct proc_dir_entry *root_irq_dir;

#ifdef CONFIG_SMP

static int irq_affinity_proc_show(struct seq_file *m, void *v)
{
	struct irq_desc *desc = irq_to_desc((long)m->private);
	cpumask_t *mask = &desc->affinity;

#ifdef CONFIG_GENERIC_PENDING_IRQ
	if (desc->status & IRQ_MOVE_PENDING)
		mask = &desc->pending_mask;
#endif
	seq_cpumask(m, mask);
	seq_putc(m, '\n');
	return 0;
}

#ifndef is_affinity_mask_valid
#define is_affinity_mask_valid(val) 1
#endif

int no_irq_affinity;
static ssize_t irq_affinity_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *pos)
{
	unsigned int irq = (int)(long)PDE(file->f_path.dentry->d_inode)->data;
	cpumask_var_t new_value;
	int err;

	if (!irq_to_desc(irq)->chip->set_affinity || no_irq_affinity ||
	    irq_balancing_disabled(irq))
		return -EIO;

	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
		return -ENOMEM;

	err = cpumask_parse_user(buffer, count, new_value);
	if (err)
		goto free_cpumask;

	if (!is_affinity_mask_valid(*new_value)) {
		err = -EINVAL;
		goto free_cpumask;
	}

	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
	if (!cpumask_intersects(new_value, cpu_online_mask)) {
		/* Special case for empty set - allow the architecture
		   code to set default SMP affinity. */
		err = irq_select_affinity_usr(irq) ? -EINVAL : count;
	} else {
		irq_set_affinity(irq, new_value);
		err = count;
	}

free_cpumask:
	free_cpumask_var(new_value);
	return err;
}

static int irq_affinity_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, irq_affinity_proc_show, PDE(inode)->data);
}

static const struct file_operations irq_affinity_proc_fops = {
	.open		= irq_affinity_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= irq_affinity_proc_write,
};

static int default_affinity_show(struct seq_file *m, void *v)
{
	seq_cpumask(m, &irq_default_affinity);
	seq_putc(m, '\n');
	return 0;
}

static ssize_t default_affinity_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
{
	cpumask_t new_value;
	int err;

	err = cpumask_parse_user(buffer, count, &new_value);
	if (err)
		return err;

	if (!is_affinity_mask_valid(new_value))
		return -EINVAL;

	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
	if (!cpus_intersects(new_value, cpu_online_map))
		return -EINVAL;

	irq_default_affinity = new_value;

	return count;
}

static int default_affinity_open(struct inode *inode, struct file *file)
{
	return single_open(file, default_affinity_show, NULL);
}

static const struct file_operations default_affinity_proc_fops = {
	.open		= default_affinity_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= default_affinity_write,
};
#endif

static int irq_spurious_read(char *page, char **start, off_t off,
				  int count, int *eof, void *data)
{
	struct irq_desc *desc = irq_to_desc((long) data);
	return sprintf(page, "count %u\n"
			     "unhandled %u\n"
			     "last_unhandled %u ms\n",
			desc->irq_count,
			desc->irqs_unhandled,
			jiffies_to_msecs(desc->last_unhandled));
}

#define MAX_NAMELEN 128

static int name_unique(unsigned int irq, struct irqaction *new_action)
{
	struct irq_desc *desc = irq_to_desc(irq);
	struct irqaction *action;
	unsigned long flags;
	int ret = 1;

	spin_lock_irqsave(&desc->lock, flags);
	for (action = desc->action ; action; action = action->next) {
		if ((action != new_action) && action->name &&
				!strcmp(new_action->name, action->name)) {
			ret = 0;
			break;
		}
	}
	spin_unlock_irqrestore(&desc->lock, flags);
	return ret;
}

void register_handler_proc(unsigned int irq, struct irqaction *action)
{
	char name [MAX_NAMELEN];
	struct irq_desc *desc = irq_to_desc(irq);

	if (!desc->dir || action->dir || !action->name ||
					!name_unique(irq, action))
		return;

	memset(name, 0, MAX_NAMELEN);
	snprintf(name, MAX_NAMELEN, "%s", action->name);

	/* create /proc/irq/1234/handler/ */
	action->dir = proc_mkdir(name, desc->dir);
}

#undef MAX_NAMELEN

#define MAX_NAMELEN 10

void register_irq_proc(unsigned int irq, struct irq_desc *desc)
{
	char name [MAX_NAMELEN];
	struct proc_dir_entry *entry;

	if (!root_irq_dir || (desc->chip == &no_irq_chip) || desc->dir)
		return;

	memset(name, 0, MAX_NAMELEN);
	sprintf(name, "%d", irq);

	/* create /proc/irq/1234 */
	desc->dir = proc_mkdir(name, root_irq_dir);

#ifdef CONFIG_SMP
	/* create /proc/irq/<irq>/smp_affinity */
	proc_create_data("smp_affinity", 0600, desc->dir,
			 &irq_affinity_proc_fops, (void *)(long)irq);
#endif

	entry = create_proc_entry("spurious", 0444, desc->dir);
	if (entry) {
		entry->data = (void *)(long)irq;
		entry->read_proc = irq_spurious_read;
	}
}

#undef MAX_NAMELEN

void unregister_handler_proc(unsigned int irq, struct irqaction *action)
{
	if (action->dir) {
		struct irq_desc *desc = irq_to_desc(irq);

		remove_proc_entry(action->dir->name, desc->dir);
	}
}

static void register_default_affinity_proc(void)
{
#ifdef CONFIG_SMP
	proc_create("irq/default_smp_affinity", 0600, NULL,
		    &default_affinity_proc_fops);
#endif
}

void init_irq_proc(void)
{
	unsigned int irq;
	struct irq_desc *desc;

	/* create /proc/irq */
	root_irq_dir = proc_mkdir("irq", NULL);
	if (!root_irq_dir)
		return;

	register_default_affinity_proc();

	/*
	 * Create entries for all existing IRQs.
	 */
	for_each_irq_desc(irq, desc) {
		if (!desc)
			continue;

		register_irq_proc(irq, desc);
	}
}

OpenPOWER on IntegriCloud