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 */
35 static struct proc_dir_entry *root_irq_dir;
36
37 #ifdef CONFIG_SMP
38
39 enum {
40 AFFINITY,
41 AFFINITY_LIST,
42 EFFECTIVE,
43 EFFECTIVE_LIST,
44 };
45
show_irq_affinity(int type,struct seq_file * m)46 static 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
irq_affinity_hint_proc_show(struct seq_file * m,void * v)83 static 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
103 int no_irq_affinity;
irq_affinity_proc_show(struct seq_file * m,void * v)104 static int irq_affinity_proc_show(struct seq_file *m, void *v)
105 {
106 return show_irq_affinity(AFFINITY, m);
107 }
108
irq_affinity_list_proc_show(struct seq_file * m,void * v)109 static 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
irq_select_affinity_usr(unsigned int irq)115 static 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. */
irq_select_affinity_usr(unsigned int irq)131 static inline int irq_select_affinity_usr(unsigned int irq)
132 {
133 return irq_select_affinity(irq);
134 }
135 #endif
136
write_irq_affinity(int type,struct file * file,const char __user * buffer,size_t count,loff_t * pos)137 static 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 (!alloc_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 #ifdef CONFIG_CPU_ISOLATION_OPT
158 if (cpumask_subset(new_value, cpu_isolated_mask)) {
159 err = -EINVAL;
160 goto free_cpumask;
161 }
162 #endif
163 /*
164 * Do not allow disabling IRQs completely - it's a too easy
165 * way to make the system unusable accidentally :-) At least
166 * one online CPU still has to be targeted.
167 */
168 if (!cpumask_intersects(new_value, cpu_online_mask)) {
169 /*
170 * Special case for empty set - allow the architecture code
171 * to set default SMP affinity.
172 */
173 err = irq_select_affinity_usr(irq) ? -EINVAL : count;
174 } else {
175 err = irq_set_affinity(irq, new_value);
176 if (!err)
177 err = count;
178 }
179
180 free_cpumask:
181 free_cpumask_var(new_value);
182 return err;
183 }
184
irq_affinity_proc_write(struct file * file,const char __user * buffer,size_t count,loff_t * pos)185 static ssize_t irq_affinity_proc_write(struct file *file,
186 const char __user *buffer, size_t count, loff_t *pos)
187 {
188 return write_irq_affinity(0, file, buffer, count, pos);
189 }
190
irq_affinity_list_proc_write(struct file * file,const char __user * buffer,size_t count,loff_t * pos)191 static ssize_t irq_affinity_list_proc_write(struct file *file,
192 const char __user *buffer, size_t count, loff_t *pos)
193 {
194 return write_irq_affinity(1, file, buffer, count, pos);
195 }
196
irq_affinity_proc_open(struct inode * inode,struct file * file)197 static int irq_affinity_proc_open(struct inode *inode, struct file *file)
198 {
199 return single_open(file, irq_affinity_proc_show, PDE_DATA(inode));
200 }
201
irq_affinity_list_proc_open(struct inode * inode,struct file * file)202 static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
203 {
204 return single_open(file, irq_affinity_list_proc_show, PDE_DATA(inode));
205 }
206
207 static const struct proc_ops irq_affinity_proc_ops = {
208 .proc_open = irq_affinity_proc_open,
209 .proc_read = seq_read,
210 .proc_lseek = seq_lseek,
211 .proc_release = single_release,
212 .proc_write = irq_affinity_proc_write,
213 };
214
215 static const struct proc_ops irq_affinity_list_proc_ops = {
216 .proc_open = irq_affinity_list_proc_open,
217 .proc_read = seq_read,
218 .proc_lseek = seq_lseek,
219 .proc_release = single_release,
220 .proc_write = irq_affinity_list_proc_write,
221 };
222
223 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
irq_effective_aff_proc_show(struct seq_file * m,void * v)224 static int irq_effective_aff_proc_show(struct seq_file *m, void *v)
225 {
226 return show_irq_affinity(EFFECTIVE, m);
227 }
228
irq_effective_aff_list_proc_show(struct seq_file * m,void * v)229 static int irq_effective_aff_list_proc_show(struct seq_file *m, void *v)
230 {
231 return show_irq_affinity(EFFECTIVE_LIST, m);
232 }
233 #endif
234
default_affinity_show(struct seq_file * m,void * v)235 static int default_affinity_show(struct seq_file *m, void *v)
236 {
237 seq_printf(m, "%*pb\n", cpumask_pr_args(irq_default_affinity));
238 return 0;
239 }
240
default_affinity_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)241 static ssize_t default_affinity_write(struct file *file,
242 const char __user *buffer, size_t count, loff_t *ppos)
243 {
244 cpumask_var_t new_value;
245 int err;
246
247 if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
248 return -ENOMEM;
249
250 err = cpumask_parse_user(buffer, count, new_value);
251 if (err)
252 goto out;
253
254 /*
255 * Do not allow disabling IRQs completely - it's a too easy
256 * way to make the system unusable accidentally :-) At least
257 * one online CPU still has to be targeted.
258 */
259 if (!cpumask_intersects(new_value, cpu_online_mask)) {
260 err = -EINVAL;
261 goto out;
262 }
263
264 cpumask_copy(irq_default_affinity, new_value);
265 err = count;
266
267 out:
268 free_cpumask_var(new_value);
269 return err;
270 }
271
default_affinity_open(struct inode * inode,struct file * file)272 static int default_affinity_open(struct inode *inode, struct file *file)
273 {
274 return single_open(file, default_affinity_show, PDE_DATA(inode));
275 }
276
277 static const struct proc_ops default_affinity_proc_ops = {
278 .proc_open = default_affinity_open,
279 .proc_read = seq_read,
280 .proc_lseek = seq_lseek,
281 .proc_release = single_release,
282 .proc_write = default_affinity_write,
283 };
284
irq_node_proc_show(struct seq_file * m,void * v)285 static int irq_node_proc_show(struct seq_file *m, void *v)
286 {
287 struct irq_desc *desc = irq_to_desc((long) m->private);
288
289 seq_printf(m, "%d\n", irq_desc_get_node(desc));
290 return 0;
291 }
292 #endif
293
irq_spurious_proc_show(struct seq_file * m,void * v)294 static int irq_spurious_proc_show(struct seq_file *m, void *v)
295 {
296 struct irq_desc *desc = irq_to_desc((long) m->private);
297
298 seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
299 desc->irq_count, desc->irqs_unhandled,
300 jiffies_to_msecs(desc->last_unhandled));
301 return 0;
302 }
303
304 #define MAX_NAMELEN 128
305
name_unique(unsigned int irq,struct irqaction * new_action)306 static int name_unique(unsigned int irq, struct irqaction *new_action)
307 {
308 struct irq_desc *desc = irq_to_desc(irq);
309 struct irqaction *action;
310 unsigned long flags;
311 int ret = 1;
312
313 raw_spin_lock_irqsave(&desc->lock, flags);
314 for_each_action_of_desc(desc, action) {
315 if ((action != new_action) && action->name &&
316 !strcmp(new_action->name, action->name)) {
317 ret = 0;
318 break;
319 }
320 }
321 raw_spin_unlock_irqrestore(&desc->lock, flags);
322 return ret;
323 }
324
register_handler_proc(unsigned int irq,struct irqaction * action)325 void register_handler_proc(unsigned int irq, struct irqaction *action)
326 {
327 char name [MAX_NAMELEN];
328 struct irq_desc *desc = irq_to_desc(irq);
329
330 if (!desc->dir || action->dir || !action->name ||
331 !name_unique(irq, action))
332 return;
333
334 snprintf(name, MAX_NAMELEN, "%s", action->name);
335
336 /* create /proc/irq/1234/handler/ */
337 action->dir = proc_mkdir(name, desc->dir);
338 }
339
340 #undef MAX_NAMELEN
341
342 #define MAX_NAMELEN 10
343
register_irq_proc(unsigned int irq,struct irq_desc * desc)344 void register_irq_proc(unsigned int irq, struct irq_desc *desc)
345 {
346 static DEFINE_MUTEX(register_lock);
347 void __maybe_unused *irqp = (void *)(unsigned long) irq;
348 char name [MAX_NAMELEN];
349
350 if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
351 return;
352
353 /*
354 * irq directories are registered only when a handler is
355 * added, not when the descriptor is created, so multiple
356 * tasks might try to register at the same time.
357 */
358 mutex_lock(®ister_lock);
359
360 if (desc->dir)
361 goto out_unlock;
362
363 sprintf(name, "%d", irq);
364
365 /* create /proc/irq/1234 */
366 desc->dir = proc_mkdir(name, root_irq_dir);
367 if (!desc->dir)
368 goto out_unlock;
369
370 #ifdef CONFIG_SMP
371 /* create /proc/irq/<irq>/smp_affinity */
372 proc_create_data("smp_affinity", 0644, desc->dir,
373 &irq_affinity_proc_ops, irqp);
374
375 /* create /proc/irq/<irq>/affinity_hint */
376 proc_create_single_data("affinity_hint", 0444, desc->dir,
377 irq_affinity_hint_proc_show, irqp);
378
379 /* create /proc/irq/<irq>/smp_affinity_list */
380 proc_create_data("smp_affinity_list", 0644, desc->dir,
381 &irq_affinity_list_proc_ops, irqp);
382
383 proc_create_single_data("node", 0444, desc->dir, irq_node_proc_show,
384 irqp);
385 # ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
386 proc_create_single_data("effective_affinity", 0444, desc->dir,
387 irq_effective_aff_proc_show, irqp);
388 proc_create_single_data("effective_affinity_list", 0444, desc->dir,
389 irq_effective_aff_list_proc_show, irqp);
390 # endif
391 #endif
392 proc_create_single_data("spurious", 0444, desc->dir,
393 irq_spurious_proc_show, (void *)(long)irq);
394
395 out_unlock:
396 mutex_unlock(®ister_lock);
397 }
398
unregister_irq_proc(unsigned int irq,struct irq_desc * desc)399 void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
400 {
401 char name [MAX_NAMELEN];
402
403 if (!root_irq_dir || !desc->dir)
404 return;
405 #ifdef CONFIG_SMP
406 remove_proc_entry("smp_affinity", desc->dir);
407 remove_proc_entry("affinity_hint", desc->dir);
408 remove_proc_entry("smp_affinity_list", desc->dir);
409 remove_proc_entry("node", desc->dir);
410 # ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
411 remove_proc_entry("effective_affinity", desc->dir);
412 remove_proc_entry("effective_affinity_list", desc->dir);
413 # endif
414 #endif
415 remove_proc_entry("spurious", desc->dir);
416
417 sprintf(name, "%u", irq);
418 remove_proc_entry(name, root_irq_dir);
419 }
420
421 #undef MAX_NAMELEN
422
unregister_handler_proc(unsigned int irq,struct irqaction * action)423 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
424 {
425 proc_remove(action->dir);
426 }
427
register_default_affinity_proc(void)428 static void register_default_affinity_proc(void)
429 {
430 #ifdef CONFIG_SMP
431 proc_create("irq/default_smp_affinity", 0644, NULL,
432 &default_affinity_proc_ops);
433 #endif
434 }
435
init_irq_proc(void)436 void init_irq_proc(void)
437 {
438 unsigned int irq;
439 struct irq_desc *desc;
440
441 /* create /proc/irq */
442 root_irq_dir = proc_mkdir("irq", NULL);
443 if (!root_irq_dir)
444 return;
445
446 register_default_affinity_proc();
447
448 /*
449 * Create entries for all existing IRQs.
450 */
451 for_each_irq_desc(irq, desc)
452 register_irq_proc(irq, desc);
453 }
454
455 #ifdef CONFIG_GENERIC_IRQ_SHOW
456
arch_show_interrupts(struct seq_file * p,int prec)457 int __weak arch_show_interrupts(struct seq_file *p, int prec)
458 {
459 return 0;
460 }
461
462 #ifndef ACTUAL_NR_IRQS
463 # define ACTUAL_NR_IRQS nr_irqs
464 #endif
465
show_interrupts(struct seq_file * p,void * v)466 int show_interrupts(struct seq_file *p, void *v)
467 {
468 static int prec;
469
470 unsigned long flags, any_count = 0;
471 int i = *(loff_t *) v, j;
472 struct irqaction *action;
473 struct irq_desc *desc;
474
475 if (i > ACTUAL_NR_IRQS)
476 return 0;
477
478 if (i == ACTUAL_NR_IRQS)
479 return arch_show_interrupts(p, prec);
480
481 /* print header and calculate the width of the first column */
482 if (i == 0) {
483 for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
484 j *= 10;
485
486 seq_printf(p, "%*s", prec + 8, "");
487 for_each_online_cpu(j)
488 seq_printf(p, "CPU%-8d", j);
489 seq_putc(p, '\n');
490 }
491
492 rcu_read_lock();
493 desc = irq_to_desc(i);
494 if (!desc || irq_settings_is_hidden(desc))
495 goto outsparse;
496
497 if (desc->kstat_irqs)
498 for_each_online_cpu(j)
499 any_count |= *per_cpu_ptr(desc->kstat_irqs, j);
500
501 if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
502 goto outsparse;
503
504 seq_printf(p, "%*d: ", prec, i);
505 for_each_online_cpu(j)
506 seq_printf(p, "%10u ", desc->kstat_irqs ?
507 *per_cpu_ptr(desc->kstat_irqs, j) : 0);
508
509 raw_spin_lock_irqsave(&desc->lock, flags);
510 if (desc->irq_data.chip) {
511 if (desc->irq_data.chip->irq_print_chip)
512 desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
513 else if (desc->irq_data.chip->name)
514 seq_printf(p, " %8s", desc->irq_data.chip->name);
515 else
516 seq_printf(p, " %8s", "-");
517 } else {
518 seq_printf(p, " %8s", "None");
519 }
520 if (desc->irq_data.domain)
521 seq_printf(p, " %*d", prec, (int) desc->irq_data.hwirq);
522 else
523 seq_printf(p, " %*s", prec, "");
524 #ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
525 seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
526 #endif
527 if (desc->name)
528 seq_printf(p, "-%-8s", desc->name);
529
530 action = desc->action;
531 if (action) {
532 seq_printf(p, " %s", action->name);
533 while ((action = action->next) != NULL)
534 seq_printf(p, ", %s", action->name);
535 }
536
537 seq_putc(p, '\n');
538 raw_spin_unlock_irqrestore(&desc->lock, flags);
539 outsparse:
540 rcu_read_unlock();
541 return 0;
542 }
543 #endif
544