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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  */
36 static struct proc_dir_entry *root_irq_dir;
37 
38 #ifdef CONFIG_SMP
39 
show_irq_affinity(int type,struct seq_file * m,void * v)40 static 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_common_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 
irq_affinity_hint_proc_show(struct seq_file * m,void * v)56 static 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 
80 int no_irq_affinity;
irq_affinity_proc_show(struct seq_file * m,void * v)81 static int irq_affinity_proc_show(struct seq_file *m, void *v)
82 {
83 	return show_irq_affinity(0, m, v);
84 }
85 
irq_affinity_list_proc_show(struct seq_file * m,void * v)86 static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
87 {
88 	return show_irq_affinity(1, m, v);
89 }
90 
91 
write_irq_affinity(int type,struct file * file,const char __user * buffer,size_t count,loff_t * pos)92 static 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 
131 free_cpumask:
132 	free_cpumask_var(new_value);
133 	return err;
134 }
135 
irq_affinity_proc_write(struct file * file,const char __user * buffer,size_t count,loff_t * pos)136 static 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 
irq_affinity_list_proc_write(struct file * file,const char __user * buffer,size_t count,loff_t * pos)142 static 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 
irq_affinity_proc_open(struct inode * inode,struct file * file)148 static 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 
irq_affinity_list_proc_open(struct inode * inode,struct file * file)153 static 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 
irq_affinity_hint_proc_open(struct inode * inode,struct file * file)158 static 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 
163 static 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 
171 static 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 
178 static 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 
default_affinity_show(struct seq_file * m,void * v)186 static 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 
default_affinity_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)192 static 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 
223 out:
224 	free_cpumask_var(new_value);
225 	return err;
226 }
227 
default_affinity_open(struct inode * inode,struct file * file)228 static int default_affinity_open(struct inode *inode, struct file *file)
229 {
230 	return single_open(file, default_affinity_show, PDE_DATA(inode));
231 }
232 
233 static 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 
irq_node_proc_show(struct seq_file * m,void * v)241 static 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", irq_desc_get_node(desc));
246 	return 0;
247 }
248 
irq_node_proc_open(struct inode * inode,struct file * file)249 static 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 
254 static 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 
irq_spurious_proc_show(struct seq_file * m,void * v)262 static 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 
irq_spurious_proc_open(struct inode * inode,struct file * file)272 static 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 
277 static 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 
name_unique(unsigned int irq,struct irqaction * new_action)286 static 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 
register_handler_proc(unsigned int irq,struct irqaction * action)305 void 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 
register_irq_proc(unsigned int irq,struct irq_desc * desc)325 void 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 
371 out_unlock:
372 	mutex_unlock(&register_lock);
373 }
374 
unregister_irq_proc(unsigned int irq,struct irq_desc * desc)375 void 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 
unregister_handler_proc(unsigned int irq,struct irqaction * action)396 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
397 {
398 	proc_remove(action->dir);
399 }
400 
register_default_affinity_proc(void)401 static 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 
init_irq_proc(void)409 void 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 
arch_show_interrupts(struct seq_file * p,int prec)434 int __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 
show_interrupts(struct seq_file * p,void * v)443 int 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 || irq_desc_is_chained(desc)) && !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');
510 out:
511 	raw_spin_unlock_irqrestore(&desc->lock, flags);
512 outsparse:
513 	irq_unlock_sparse();
514 	return 0;
515 }
516 #endif
517