1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
4 *
5 * This file contains the /proc/irq/ handling code.
6 */
7
8#include <linux/irq.h>
9#include <linux/gfp.h>
10#include <linux/proc_fs.h>
11#include <linux/seq_file.h>
12#include <linux/interrupt.h>
13#include <linux/kernel_stat.h>
14#include <linux/mutex.h>
15
16#include "internals.h"
17
18/*
19 * Access rules:
20 *
21 * procfs protects read/write of /proc/irq/N/ files against a
22 * concurrent free of the interrupt descriptor. remove_proc_entry()
23 * immediately prevents new read/writes to happen and waits for
24 * already running read/write functions to complete.
25 *
26 * We remove the proc entries first and then delete the interrupt
27 * descriptor from the radix tree and free it. So it is guaranteed
28 * that irq_to_desc(N) is valid as long as the read/writes are
29 * permitted by procfs.
30 *
31 * The read from /proc/interrupts is a different problem because there
32 * is no protection. So the lookup and the access to irqdesc
33 * information must be protected by sparse_irq_lock.
34 */
35static struct proc_dir_entry *root_irq_dir;
36
37#ifdef CONFIG_SMP
38
39enum {
40	AFFINITY,
41	AFFINITY_LIST,
42	EFFECTIVE,
43	EFFECTIVE_LIST,
44};
45
46static int show_irq_affinity(int type, struct seq_file *m)
47{
48	struct irq_desc *desc = irq_to_desc((long)m->private);
49	const struct cpumask *mask;
50
51	switch (type) {
52	case AFFINITY:
53	case AFFINITY_LIST:
54		mask = desc->irq_common_data.affinity;
55#ifdef CONFIG_GENERIC_PENDING_IRQ
56		if (irqd_is_setaffinity_pending(&desc->irq_data))
57			mask = desc->pending_mask;
58#endif
59		break;
60	case EFFECTIVE:
61	case EFFECTIVE_LIST:
62#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
63		mask = irq_data_get_effective_affinity_mask(&desc->irq_data);
64		break;
65#endif
66	default:
67		return -EINVAL;
68	}
69
70	switch (type) {
71	case AFFINITY_LIST:
72	case EFFECTIVE_LIST:
73		seq_printf(m, "%*pbl\n", cpumask_pr_args(mask));
74		break;
75	case AFFINITY:
76	case EFFECTIVE:
77		seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
78		break;
79	}
80	return 0;
81}
82
83static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
84{
85	struct irq_desc *desc = irq_to_desc((long)m->private);
86	unsigned long flags;
87	cpumask_var_t mask;
88
89	if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
90		return -ENOMEM;
91
92	raw_spin_lock_irqsave(&desc->lock, flags);
93	if (desc->affinity_hint)
94		cpumask_copy(mask, desc->affinity_hint);
95	raw_spin_unlock_irqrestore(&desc->lock, flags);
96
97	seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
98	free_cpumask_var(mask);
99
100	return 0;
101}
102
103int no_irq_affinity;
104static int irq_affinity_proc_show(struct seq_file *m, void *v)
105{
106	return show_irq_affinity(AFFINITY, m);
107}
108
109static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
110{
111	return show_irq_affinity(AFFINITY_LIST, m);
112}
113
114#ifndef CONFIG_AUTO_IRQ_AFFINITY
115static inline int irq_select_affinity_usr(unsigned int irq)
116{
117	/*
118	 * If the interrupt is started up already then this fails. The
119	 * interrupt is assigned to an online CPU already. There is no
120	 * point to move it around randomly. Tell user space that the
121	 * selected mask is bogus.
122	 *
123	 * If not then any change to the affinity is pointless because the
124	 * startup code invokes irq_setup_affinity() which will select
125	 * a online CPU anyway.
126	 */
127	return -EINVAL;
128}
129#else
130/* ALPHA magic affinity auto selector. Keep it for historical reasons. */
131static inline int irq_select_affinity_usr(unsigned int irq)
132{
133	return irq_select_affinity(irq);
134}
135#endif
136
137static ssize_t write_irq_affinity(int type, struct file *file,
138		const char __user *buffer, size_t count, loff_t *pos)
139{
140	unsigned int irq = (int)(long)pde_data(file_inode(file));
141	cpumask_var_t new_value;
142	int err;
143
144	if (!irq_can_set_affinity_usr(irq) || no_irq_affinity)
145		return -EIO;
146
147	if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
148		return -ENOMEM;
149
150	if (type)
151		err = cpumask_parselist_user(buffer, count, new_value);
152	else
153		err = cpumask_parse_user(buffer, count, new_value);
154	if (err)
155		goto free_cpumask;
156
157	/*
158	 * Do not allow disabling IRQs completely - it's a too easy
159	 * way to make the system unusable accidentally :-) At least
160	 * one online CPU still has to be targeted.
161	 */
162	if (!cpumask_intersects(new_value, cpu_online_mask)) {
163		/*
164		 * Special case for empty set - allow the architecture code
165		 * to set default SMP affinity.
166		 */
167		err = irq_select_affinity_usr(irq) ? -EINVAL : count;
168	} else {
169		err = irq_set_affinity(irq, new_value);
170		if (!err)
171			err = count;
172	}
173
174free_cpumask:
175	free_cpumask_var(new_value);
176	return err;
177}
178
179static ssize_t irq_affinity_proc_write(struct file *file,
180		const char __user *buffer, size_t count, loff_t *pos)
181{
182	return write_irq_affinity(0, file, buffer, count, pos);
183}
184
185static ssize_t irq_affinity_list_proc_write(struct file *file,
186		const char __user *buffer, size_t count, loff_t *pos)
187{
188	return write_irq_affinity(1, file, buffer, count, pos);
189}
190
191static int irq_affinity_proc_open(struct inode *inode, struct file *file)
192{
193	return single_open(file, irq_affinity_proc_show, pde_data(inode));
194}
195
196static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
197{
198	return single_open(file, irq_affinity_list_proc_show, pde_data(inode));
199}
200
201static const struct proc_ops irq_affinity_proc_ops = {
202	.proc_open	= irq_affinity_proc_open,
203	.proc_read	= seq_read,
204	.proc_lseek	= seq_lseek,
205	.proc_release	= single_release,
206	.proc_write	= irq_affinity_proc_write,
207};
208
209static const struct proc_ops irq_affinity_list_proc_ops = {
210	.proc_open	= irq_affinity_list_proc_open,
211	.proc_read	= seq_read,
212	.proc_lseek	= seq_lseek,
213	.proc_release	= single_release,
214	.proc_write	= irq_affinity_list_proc_write,
215};
216
217#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
218static int irq_effective_aff_proc_show(struct seq_file *m, void *v)
219{
220	return show_irq_affinity(EFFECTIVE, m);
221}
222
223static int irq_effective_aff_list_proc_show(struct seq_file *m, void *v)
224{
225	return show_irq_affinity(EFFECTIVE_LIST, m);
226}
227#endif
228
229static int default_affinity_show(struct seq_file *m, void *v)
230{
231	seq_printf(m, "%*pb\n", cpumask_pr_args(irq_default_affinity));
232	return 0;
233}
234
235static ssize_t default_affinity_write(struct file *file,
236		const char __user *buffer, size_t count, loff_t *ppos)
237{
238	cpumask_var_t new_value;
239	int err;
240
241	if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
242		return -ENOMEM;
243
244	err = cpumask_parse_user(buffer, count, new_value);
245	if (err)
246		goto out;
247
248	/*
249	 * Do not allow disabling IRQs completely - it's a too easy
250	 * way to make the system unusable accidentally :-) At least
251	 * one online CPU still has to be targeted.
252	 */
253	if (!cpumask_intersects(new_value, cpu_online_mask)) {
254		err = -EINVAL;
255		goto out;
256	}
257
258	cpumask_copy(irq_default_affinity, new_value);
259	err = count;
260
261out:
262	free_cpumask_var(new_value);
263	return err;
264}
265
266static int default_affinity_open(struct inode *inode, struct file *file)
267{
268	return single_open(file, default_affinity_show, pde_data(inode));
269}
270
271static const struct proc_ops default_affinity_proc_ops = {
272	.proc_open	= default_affinity_open,
273	.proc_read	= seq_read,
274	.proc_lseek	= seq_lseek,
275	.proc_release	= single_release,
276	.proc_write	= default_affinity_write,
277};
278
279static int irq_node_proc_show(struct seq_file *m, void *v)
280{
281	struct irq_desc *desc = irq_to_desc((long) m->private);
282
283	seq_printf(m, "%d\n", irq_desc_get_node(desc));
284	return 0;
285}
286#endif
287
288static int irq_spurious_proc_show(struct seq_file *m, void *v)
289{
290	struct irq_desc *desc = irq_to_desc((long) m->private);
291
292	seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
293		   desc->irq_count, desc->irqs_unhandled,
294		   jiffies_to_msecs(desc->last_unhandled));
295	return 0;
296}
297
298#define MAX_NAMELEN 128
299
300static int name_unique(unsigned int irq, struct irqaction *new_action)
301{
302	struct irq_desc *desc = irq_to_desc(irq);
303	struct irqaction *action;
304	unsigned long flags;
305	int ret = 1;
306
307	raw_spin_lock_irqsave(&desc->lock, flags);
308	for_each_action_of_desc(desc, action) {
309		if ((action != new_action) && action->name &&
310				!strcmp(new_action->name, action->name)) {
311			ret = 0;
312			break;
313		}
314	}
315	raw_spin_unlock_irqrestore(&desc->lock, flags);
316	return ret;
317}
318
319void register_handler_proc(unsigned int irq, struct irqaction *action)
320{
321	char name [MAX_NAMELEN];
322	struct irq_desc *desc = irq_to_desc(irq);
323
324	if (!desc->dir || action->dir || !action->name ||
325					!name_unique(irq, action))
326		return;
327
328	snprintf(name, MAX_NAMELEN, "%s", action->name);
329
330	/* create /proc/irq/1234/handler/ */
331	action->dir = proc_mkdir(name, desc->dir);
332}
333
334#undef MAX_NAMELEN
335
336#define MAX_NAMELEN 10
337
338void register_irq_proc(unsigned int irq, struct irq_desc *desc)
339{
340	static DEFINE_MUTEX(register_lock);
341	void __maybe_unused *irqp = (void *)(unsigned long) irq;
342	char name [MAX_NAMELEN];
343
344	if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
345		return;
346
347	/*
348	 * irq directories are registered only when a handler is
349	 * added, not when the descriptor is created, so multiple
350	 * tasks might try to register at the same time.
351	 */
352	mutex_lock(&register_lock);
353
354	if (desc->dir)
355		goto out_unlock;
356
357	sprintf(name, "%d", irq);
358
359	/* create /proc/irq/1234 */
360	desc->dir = proc_mkdir(name, root_irq_dir);
361	if (!desc->dir)
362		goto out_unlock;
363
364#ifdef CONFIG_SMP
365	/* create /proc/irq/<irq>/smp_affinity */
366	proc_create_data("smp_affinity", 0644, desc->dir,
367			 &irq_affinity_proc_ops, irqp);
368
369	/* create /proc/irq/<irq>/affinity_hint */
370	proc_create_single_data("affinity_hint", 0444, desc->dir,
371			irq_affinity_hint_proc_show, irqp);
372
373	/* create /proc/irq/<irq>/smp_affinity_list */
374	proc_create_data("smp_affinity_list", 0644, desc->dir,
375			 &irq_affinity_list_proc_ops, irqp);
376
377	proc_create_single_data("node", 0444, desc->dir, irq_node_proc_show,
378			irqp);
379# ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
380	proc_create_single_data("effective_affinity", 0444, desc->dir,
381			irq_effective_aff_proc_show, irqp);
382	proc_create_single_data("effective_affinity_list", 0444, desc->dir,
383			irq_effective_aff_list_proc_show, irqp);
384# endif
385#endif
386	proc_create_single_data("spurious", 0444, desc->dir,
387			irq_spurious_proc_show, (void *)(long)irq);
388
389out_unlock:
390	mutex_unlock(&register_lock);
391}
392
393void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
394{
395	char name [MAX_NAMELEN];
396
397	if (!root_irq_dir || !desc->dir)
398		return;
399#ifdef CONFIG_SMP
400	remove_proc_entry("smp_affinity", desc->dir);
401	remove_proc_entry("affinity_hint", desc->dir);
402	remove_proc_entry("smp_affinity_list", desc->dir);
403	remove_proc_entry("node", desc->dir);
404# ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
405	remove_proc_entry("effective_affinity", desc->dir);
406	remove_proc_entry("effective_affinity_list", desc->dir);
407# endif
408#endif
409	remove_proc_entry("spurious", desc->dir);
410
411	sprintf(name, "%u", irq);
412	remove_proc_entry(name, root_irq_dir);
413}
414
415#undef MAX_NAMELEN
416
417void unregister_handler_proc(unsigned int irq, struct irqaction *action)
418{
419	proc_remove(action->dir);
420}
421
422static void register_default_affinity_proc(void)
423{
424#ifdef CONFIG_SMP
425	proc_create("irq/default_smp_affinity", 0644, NULL,
426		    &default_affinity_proc_ops);
427#endif
428}
429
430void init_irq_proc(void)
431{
432	unsigned int irq;
433	struct irq_desc *desc;
434
435	/* create /proc/irq */
436	root_irq_dir = proc_mkdir("irq", NULL);
437	if (!root_irq_dir)
438		return;
439
440	register_default_affinity_proc();
441
442	/*
443	 * Create entries for all existing IRQs.
444	 */
445	for_each_irq_desc(irq, desc)
446		register_irq_proc(irq, desc);
447}
448
449#ifdef CONFIG_GENERIC_IRQ_SHOW
450
451int __weak arch_show_interrupts(struct seq_file *p, int prec)
452{
453	return 0;
454}
455
456#ifndef ACTUAL_NR_IRQS
457# define ACTUAL_NR_IRQS nr_irqs
458#endif
459
460int show_interrupts(struct seq_file *p, void *v)
461{
462	static int prec;
463
464	unsigned long flags, any_count = 0;
465	int i = *(loff_t *) v, j;
466	struct irqaction *action;
467	struct irq_desc *desc;
468
469	if (i > ACTUAL_NR_IRQS)
470		return 0;
471
472	if (i == ACTUAL_NR_IRQS)
473		return arch_show_interrupts(p, prec);
474
475	/* print header and calculate the width of the first column */
476	if (i == 0) {
477		for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
478			j *= 10;
479
480		seq_printf(p, "%*s", prec + 8, "");
481		for_each_online_cpu(j)
482			seq_printf(p, "CPU%-8d", j);
483		seq_putc(p, '\n');
484	}
485
486	rcu_read_lock();
487	desc = irq_to_desc(i);
488	if (!desc || irq_settings_is_hidden(desc))
489		goto outsparse;
490
491	if (desc->kstat_irqs) {
492		for_each_online_cpu(j)
493			any_count |= data_race(*per_cpu_ptr(desc->kstat_irqs, j));
494	}
495
496	if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
497		goto outsparse;
498
499	seq_printf(p, "%*d: ", prec, i);
500	for_each_online_cpu(j)
501		seq_printf(p, "%10u ", desc->kstat_irqs ?
502					*per_cpu_ptr(desc->kstat_irqs, j) : 0);
503
504	raw_spin_lock_irqsave(&desc->lock, flags);
505	if (desc->irq_data.chip) {
506		if (desc->irq_data.chip->irq_print_chip)
507			desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
508		else if (desc->irq_data.chip->name)
509			seq_printf(p, " %8s", desc->irq_data.chip->name);
510		else
511			seq_printf(p, " %8s", "-");
512	} else {
513		seq_printf(p, " %8s", "None");
514	}
515	if (desc->irq_data.domain)
516		seq_printf(p, " %*lu", prec, desc->irq_data.hwirq);
517	else
518		seq_printf(p, " %*s", prec, "");
519#ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
520	seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
521#endif
522	if (desc->name)
523		seq_printf(p, "-%-8s", desc->name);
524
525	action = desc->action;
526	if (action) {
527		seq_printf(p, "  %s", action->name);
528		while ((action = action->next) != NULL)
529			seq_printf(p, ", %s", action->name);
530	}
531
532	seq_putc(p, '\n');
533	raw_spin_unlock_irqrestore(&desc->lock, flags);
534outsparse:
535	rcu_read_unlock();
536	return 0;
537}
538#endif
539