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(irq: (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(d: &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(d: &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, fmt: "%*pbl\n", cpumask_pr_args(mask));
74 break;
75 case AFFINITY:
76 case EFFECTIVE:
77 seq_printf(m, fmt: "%*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(irq: (long)m->private);
86 unsigned long flags;
87 cpumask_var_t mask;
88
89 if (!zalloc_cpumask_var(mask: &mask, GFP_KERNEL))
90 return -ENOMEM;
91
92 raw_spin_lock_irqsave(&desc->lock, flags);
93 if (desc->affinity_hint)
94 cpumask_copy(dstp: mask, srcp: desc->affinity_hint);
95 raw_spin_unlock_irqrestore(&desc->lock, flags);
96
97 seq_printf(m, fmt: "%*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(type: AFFINITY, m);
107}
108
109static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
110{
111 return show_irq_affinity(type: 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(inode: file_inode(f: 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(mask: &new_value, GFP_KERNEL))
148 return -ENOMEM;
149
150 if (type)
151 err = cpumask_parselist_user(buf: buffer, len: count, dstp: new_value);
152 else
153 err = cpumask_parse_user(buf: buffer, len: count, dstp: 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(src1p: 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, cpumask: new_value);
170 if (!err)
171 err = count;
172 }
173
174free_cpumask:
175 free_cpumask_var(mask: 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(type: 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(type: 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(type: EFFECTIVE, m);
221}
222
223static int irq_effective_aff_list_proc_show(struct seq_file *m, void *v)
224{
225 return show_irq_affinity(type: EFFECTIVE_LIST, m);
226}
227#endif
228
229static int default_affinity_show(struct seq_file *m, void *v)
230{
231 seq_printf(m, fmt: "%*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(mask: &new_value, GFP_KERNEL))
242 return -ENOMEM;
243
244 err = cpumask_parse_user(buf: buffer, len: count, dstp: 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(src1p: new_value, cpu_online_mask)) {
254 err = -EINVAL;
255 goto out;
256 }
257
258 cpumask_copy(dstp: irq_default_affinity, srcp: new_value);
259 err = count;
260
261out:
262 free_cpumask_var(mask: 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(irq: (long) m->private);
282
283 seq_printf(m, fmt: "%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(irq: (long) m->private);
291
292 seq_printf(m, fmt: "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
293 desc->irq_count, desc->irqs_unhandled,
294 jiffies_to_msecs(j: 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, new_action: action))
326 return;
327
328 snprintf(buf: name, MAX_NAMELEN, fmt: "%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(buf: name, fmt: "%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(name: "affinity_hint", mode: 0444, parent: desc->dir,
371 show: irq_affinity_hint_proc_show, data: 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(name: "node", mode: 0444, parent: desc->dir, show: irq_node_proc_show,
378 data: irqp);
379# ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
380 proc_create_single_data(name: "effective_affinity", mode: 0444, parent: desc->dir,
381 show: irq_effective_aff_proc_show, data: irqp);
382 proc_create_single_data(name: "effective_affinity_list", mode: 0444, parent: desc->dir,
383 show: irq_effective_aff_list_proc_show, data: irqp);
384# endif
385#endif
386 proc_create_single_data(name: "spurious", mode: 0444, parent: desc->dir,
387 show: irq_spurious_proc_show, data: (void *)(long)irq);
388
389out_unlock:
390 mutex_unlock(lock: &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(buf: name, fmt: "%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(name: "irq/default_smp_affinity", mode: 0644, NULL,
426 proc_ops: &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(m: p, fmt: "%*s", prec + 8, "");
481 for_each_online_cpu(j)
482 seq_printf(m: p, fmt: "CPU%-8d", j);
483 seq_putc(m: p, c: '\n');
484 }
485
486 rcu_read_lock();
487 desc = irq_to_desc(irq: 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(m: p, fmt: "%*d: ", prec, i);
500 for_each_online_cpu(j)
501 seq_printf(m: p, fmt: "%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(m: p, fmt: " %8s", desc->irq_data.chip->name);
510 else
511 seq_printf(m: p, fmt: " %8s", "-");
512 } else {
513 seq_printf(m: p, fmt: " %8s", "None");
514 }
515 if (desc->irq_data.domain)
516 seq_printf(m: p, fmt: " %*lu", prec, desc->irq_data.hwirq);
517 else
518 seq_printf(m: p, fmt: " %*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(m: p, fmt: "-%-8s", desc->name);
524
525 action = desc->action;
526 if (action) {
527 seq_printf(m: p, fmt: " %s", action->name);
528 while ((action = action->next) != NULL)
529 seq_printf(m: p, fmt: ", %s", action->name);
530 }
531
532 seq_putc(m: p, c: '\n');
533 raw_spin_unlock_irqrestore(&desc->lock, flags);
534outsparse:
535 rcu_read_unlock();
536 return 0;
537}
538#endif
539

source code of linux/kernel/irq/proc.c