1/*
2 * linux/kernel/irq/proc.c
3 *
4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5 *
6 * This file contains the /proc/irq/ handling code.
7 */
8
9#include <linux/irq.h>
10#include <linux/gfp.h>
11#include <linux/proc_fs.h>
12#include <linux/seq_file.h>
13#include <linux/interrupt.h>
14#include <linux/kernel_stat.h>
15#include <linux/mutex.h>
16
17#include "internals.h"
18
19/*
20 * Access rules:
21 *
22 * procfs protects read/write of /proc/irq/N/ files against a
23 * concurrent free of the interrupt descriptor. remove_proc_entry()
24 * immediately prevents new read/writes to happen and waits for
25 * already running read/write functions to complete.
26 *
27 * We remove the proc entries first and then delete the interrupt
28 * descriptor from the radix tree and free it. So it is guaranteed
29 * that irq_to_desc(N) is valid as long as the read/writes are
30 * permitted by procfs.
31 *
32 * The read from /proc/interrupts is a different problem because there
33 * is no protection. So the lookup and the access to irqdesc
34 * information must be protected by sparse_irq_lock.
35 */
36static struct proc_dir_entry *root_irq_dir;
37
38#ifdef CONFIG_SMP
39
40static int show_irq_affinity(int type, struct seq_file *m, void *v)
41{
42	struct irq_desc *desc = irq_to_desc((long)m->private);
43	const struct cpumask *mask = desc->irq_data.affinity;
44
45#ifdef CONFIG_GENERIC_PENDING_IRQ
46	if (irqd_is_setaffinity_pending(&desc->irq_data))
47		mask = desc->pending_mask;
48#endif
49	if (type)
50		seq_printf(m, "%*pbl\n", cpumask_pr_args(mask));
51	else
52		seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
53	return 0;
54}
55
56static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
57{
58	struct irq_desc *desc = irq_to_desc((long)m->private);
59	unsigned long flags;
60	cpumask_var_t mask;
61
62	if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
63		return -ENOMEM;
64
65	raw_spin_lock_irqsave(&desc->lock, flags);
66	if (desc->affinity_hint)
67		cpumask_copy(mask, desc->affinity_hint);
68	raw_spin_unlock_irqrestore(&desc->lock, flags);
69
70	seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
71	free_cpumask_var(mask);
72
73	return 0;
74}
75
76#ifndef is_affinity_mask_valid
77#define is_affinity_mask_valid(val) 1
78#endif
79
80int no_irq_affinity;
81static int irq_affinity_proc_show(struct seq_file *m, void *v)
82{
83	return show_irq_affinity(0, m, v);
84}
85
86static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
87{
88	return show_irq_affinity(1, m, v);
89}
90
91
92static ssize_t write_irq_affinity(int type, struct file *file,
93		const char __user *buffer, size_t count, loff_t *pos)
94{
95	unsigned int irq = (int)(long)PDE_DATA(file_inode(file));
96	cpumask_var_t new_value;
97	int err;
98
99	if (!irq_can_set_affinity(irq) || no_irq_affinity)
100		return -EIO;
101
102	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
103		return -ENOMEM;
104
105	if (type)
106		err = cpumask_parselist_user(buffer, count, new_value);
107	else
108		err = cpumask_parse_user(buffer, count, new_value);
109	if (err)
110		goto free_cpumask;
111
112	if (!is_affinity_mask_valid(new_value)) {
113		err = -EINVAL;
114		goto free_cpumask;
115	}
116
117	/*
118	 * Do not allow disabling IRQs completely - it's a too easy
119	 * way to make the system unusable accidentally :-) At least
120	 * one online CPU still has to be targeted.
121	 */
122	if (!cpumask_intersects(new_value, cpu_online_mask)) {
123		/* Special case for empty set - allow the architecture
124		   code to set default SMP affinity. */
125		err = irq_select_affinity_usr(irq, new_value) ? -EINVAL : count;
126	} else {
127		irq_set_affinity(irq, new_value);
128		err = count;
129	}
130
131free_cpumask:
132	free_cpumask_var(new_value);
133	return err;
134}
135
136static ssize_t irq_affinity_proc_write(struct file *file,
137		const char __user *buffer, size_t count, loff_t *pos)
138{
139	return write_irq_affinity(0, file, buffer, count, pos);
140}
141
142static ssize_t irq_affinity_list_proc_write(struct file *file,
143		const char __user *buffer, size_t count, loff_t *pos)
144{
145	return write_irq_affinity(1, file, buffer, count, pos);
146}
147
148static int irq_affinity_proc_open(struct inode *inode, struct file *file)
149{
150	return single_open(file, irq_affinity_proc_show, PDE_DATA(inode));
151}
152
153static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
154{
155	return single_open(file, irq_affinity_list_proc_show, PDE_DATA(inode));
156}
157
158static int irq_affinity_hint_proc_open(struct inode *inode, struct file *file)
159{
160	return single_open(file, irq_affinity_hint_proc_show, PDE_DATA(inode));
161}
162
163static const struct file_operations irq_affinity_proc_fops = {
164	.open		= irq_affinity_proc_open,
165	.read		= seq_read,
166	.llseek		= seq_lseek,
167	.release	= single_release,
168	.write		= irq_affinity_proc_write,
169};
170
171static const struct file_operations irq_affinity_hint_proc_fops = {
172	.open		= irq_affinity_hint_proc_open,
173	.read		= seq_read,
174	.llseek		= seq_lseek,
175	.release	= single_release,
176};
177
178static const struct file_operations irq_affinity_list_proc_fops = {
179	.open		= irq_affinity_list_proc_open,
180	.read		= seq_read,
181	.llseek		= seq_lseek,
182	.release	= single_release,
183	.write		= irq_affinity_list_proc_write,
184};
185
186static int default_affinity_show(struct seq_file *m, void *v)
187{
188	seq_printf(m, "%*pb\n", cpumask_pr_args(irq_default_affinity));
189	return 0;
190}
191
192static ssize_t default_affinity_write(struct file *file,
193		const char __user *buffer, size_t count, loff_t *ppos)
194{
195	cpumask_var_t new_value;
196	int err;
197
198	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
199		return -ENOMEM;
200
201	err = cpumask_parse_user(buffer, count, new_value);
202	if (err)
203		goto out;
204
205	if (!is_affinity_mask_valid(new_value)) {
206		err = -EINVAL;
207		goto out;
208	}
209
210	/*
211	 * Do not allow disabling IRQs completely - it's a too easy
212	 * way to make the system unusable accidentally :-) At least
213	 * one online CPU still has to be targeted.
214	 */
215	if (!cpumask_intersects(new_value, cpu_online_mask)) {
216		err = -EINVAL;
217		goto out;
218	}
219
220	cpumask_copy(irq_default_affinity, new_value);
221	err = count;
222
223out:
224	free_cpumask_var(new_value);
225	return err;
226}
227
228static int default_affinity_open(struct inode *inode, struct file *file)
229{
230	return single_open(file, default_affinity_show, PDE_DATA(inode));
231}
232
233static const struct file_operations default_affinity_proc_fops = {
234	.open		= default_affinity_open,
235	.read		= seq_read,
236	.llseek		= seq_lseek,
237	.release	= single_release,
238	.write		= default_affinity_write,
239};
240
241static int irq_node_proc_show(struct seq_file *m, void *v)
242{
243	struct irq_desc *desc = irq_to_desc((long) m->private);
244
245	seq_printf(m, "%d\n", desc->irq_data.node);
246	return 0;
247}
248
249static int irq_node_proc_open(struct inode *inode, struct file *file)
250{
251	return single_open(file, irq_node_proc_show, PDE_DATA(inode));
252}
253
254static const struct file_operations irq_node_proc_fops = {
255	.open		= irq_node_proc_open,
256	.read		= seq_read,
257	.llseek		= seq_lseek,
258	.release	= single_release,
259};
260#endif
261
262static int irq_spurious_proc_show(struct seq_file *m, void *v)
263{
264	struct irq_desc *desc = irq_to_desc((long) m->private);
265
266	seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
267		   desc->irq_count, desc->irqs_unhandled,
268		   jiffies_to_msecs(desc->last_unhandled));
269	return 0;
270}
271
272static int irq_spurious_proc_open(struct inode *inode, struct file *file)
273{
274	return single_open(file, irq_spurious_proc_show, PDE_DATA(inode));
275}
276
277static const struct file_operations irq_spurious_proc_fops = {
278	.open		= irq_spurious_proc_open,
279	.read		= seq_read,
280	.llseek		= seq_lseek,
281	.release	= single_release,
282};
283
284#define MAX_NAMELEN 128
285
286static int name_unique(unsigned int irq, struct irqaction *new_action)
287{
288	struct irq_desc *desc = irq_to_desc(irq);
289	struct irqaction *action;
290	unsigned long flags;
291	int ret = 1;
292
293	raw_spin_lock_irqsave(&desc->lock, flags);
294	for (action = desc->action ; action; action = action->next) {
295		if ((action != new_action) && action->name &&
296				!strcmp(new_action->name, action->name)) {
297			ret = 0;
298			break;
299		}
300	}
301	raw_spin_unlock_irqrestore(&desc->lock, flags);
302	return ret;
303}
304
305void register_handler_proc(unsigned int irq, struct irqaction *action)
306{
307	char name [MAX_NAMELEN];
308	struct irq_desc *desc = irq_to_desc(irq);
309
310	if (!desc->dir || action->dir || !action->name ||
311					!name_unique(irq, action))
312		return;
313
314	memset(name, 0, MAX_NAMELEN);
315	snprintf(name, MAX_NAMELEN, "%s", action->name);
316
317	/* create /proc/irq/1234/handler/ */
318	action->dir = proc_mkdir(name, desc->dir);
319}
320
321#undef MAX_NAMELEN
322
323#define MAX_NAMELEN 10
324
325void register_irq_proc(unsigned int irq, struct irq_desc *desc)
326{
327	static DEFINE_MUTEX(register_lock);
328	char name [MAX_NAMELEN];
329
330	if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
331		return;
332
333	/*
334	 * irq directories are registered only when a handler is
335	 * added, not when the descriptor is created, so multiple
336	 * tasks might try to register at the same time.
337	 */
338	mutex_lock(&register_lock);
339
340	if (desc->dir)
341		goto out_unlock;
342
343	memset(name, 0, MAX_NAMELEN);
344	sprintf(name, "%d", irq);
345
346	/* create /proc/irq/1234 */
347	desc->dir = proc_mkdir(name, root_irq_dir);
348	if (!desc->dir)
349		goto out_unlock;
350
351#ifdef CONFIG_SMP
352	/* create /proc/irq/<irq>/smp_affinity */
353	proc_create_data("smp_affinity", 0644, desc->dir,
354			 &irq_affinity_proc_fops, (void *)(long)irq);
355
356	/* create /proc/irq/<irq>/affinity_hint */
357	proc_create_data("affinity_hint", 0444, desc->dir,
358			 &irq_affinity_hint_proc_fops, (void *)(long)irq);
359
360	/* create /proc/irq/<irq>/smp_affinity_list */
361	proc_create_data("smp_affinity_list", 0644, desc->dir,
362			 &irq_affinity_list_proc_fops, (void *)(long)irq);
363
364	proc_create_data("node", 0444, desc->dir,
365			 &irq_node_proc_fops, (void *)(long)irq);
366#endif
367
368	proc_create_data("spurious", 0444, desc->dir,
369			 &irq_spurious_proc_fops, (void *)(long)irq);
370
371out_unlock:
372	mutex_unlock(&register_lock);
373}
374
375void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
376{
377	char name [MAX_NAMELEN];
378
379	if (!root_irq_dir || !desc->dir)
380		return;
381#ifdef CONFIG_SMP
382	remove_proc_entry("smp_affinity", desc->dir);
383	remove_proc_entry("affinity_hint", desc->dir);
384	remove_proc_entry("smp_affinity_list", desc->dir);
385	remove_proc_entry("node", desc->dir);
386#endif
387	remove_proc_entry("spurious", desc->dir);
388
389	memset(name, 0, MAX_NAMELEN);
390	sprintf(name, "%u", irq);
391	remove_proc_entry(name, root_irq_dir);
392}
393
394#undef MAX_NAMELEN
395
396void unregister_handler_proc(unsigned int irq, struct irqaction *action)
397{
398	proc_remove(action->dir);
399}
400
401static void register_default_affinity_proc(void)
402{
403#ifdef CONFIG_SMP
404	proc_create("irq/default_smp_affinity", 0644, NULL,
405		    &default_affinity_proc_fops);
406#endif
407}
408
409void init_irq_proc(void)
410{
411	unsigned int irq;
412	struct irq_desc *desc;
413
414	/* create /proc/irq */
415	root_irq_dir = proc_mkdir("irq", NULL);
416	if (!root_irq_dir)
417		return;
418
419	register_default_affinity_proc();
420
421	/*
422	 * Create entries for all existing IRQs.
423	 */
424	for_each_irq_desc(irq, desc) {
425		if (!desc)
426			continue;
427
428		register_irq_proc(irq, desc);
429	}
430}
431
432#ifdef CONFIG_GENERIC_IRQ_SHOW
433
434int __weak arch_show_interrupts(struct seq_file *p, int prec)
435{
436	return 0;
437}
438
439#ifndef ACTUAL_NR_IRQS
440# define ACTUAL_NR_IRQS nr_irqs
441#endif
442
443int show_interrupts(struct seq_file *p, void *v)
444{
445	static int prec;
446
447	unsigned long flags, any_count = 0;
448	int i = *(loff_t *) v, j;
449	struct irqaction *action;
450	struct irq_desc *desc;
451
452	if (i > ACTUAL_NR_IRQS)
453		return 0;
454
455	if (i == ACTUAL_NR_IRQS)
456		return arch_show_interrupts(p, prec);
457
458	/* print header and calculate the width of the first column */
459	if (i == 0) {
460		for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
461			j *= 10;
462
463		seq_printf(p, "%*s", prec + 8, "");
464		for_each_online_cpu(j)
465			seq_printf(p, "CPU%-8d", j);
466		seq_putc(p, '\n');
467	}
468
469	irq_lock_sparse();
470	desc = irq_to_desc(i);
471	if (!desc)
472		goto outsparse;
473
474	raw_spin_lock_irqsave(&desc->lock, flags);
475	for_each_online_cpu(j)
476		any_count |= kstat_irqs_cpu(i, j);
477	action = desc->action;
478	if (!action && !any_count)
479		goto out;
480
481	seq_printf(p, "%*d: ", prec, i);
482	for_each_online_cpu(j)
483		seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
484
485	if (desc->irq_data.chip) {
486		if (desc->irq_data.chip->irq_print_chip)
487			desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
488		else if (desc->irq_data.chip->name)
489			seq_printf(p, " %8s", desc->irq_data.chip->name);
490		else
491			seq_printf(p, " %8s", "-");
492	} else {
493		seq_printf(p, " %8s", "None");
494	}
495	if (desc->irq_data.domain)
496		seq_printf(p, " %*d", prec, (int) desc->irq_data.hwirq);
497#ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
498	seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
499#endif
500	if (desc->name)
501		seq_printf(p, "-%-8s", desc->name);
502
503	if (action) {
504		seq_printf(p, "  %s", action->name);
505		while ((action = action->next) != NULL)
506			seq_printf(p, ", %s", action->name);
507	}
508
509	seq_putc(p, '\n');
510out:
511	raw_spin_unlock_irqrestore(&desc->lock, flags);
512outsparse:
513	irq_unlock_sparse();
514	return 0;
515}
516#endif
517