kernel/irq/proc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/kernel/irq/proc.c
   4  *
   5  * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
   6  *
   7  * This file contains the /proc/irq/ handling code.
   8  */
   9
  10 #include <linux/irq.h>
  11 #include <linux/gfp.h>
  12 #include <linux/proc_fs.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/kernel_stat.h>
  16 #include <linux/mutex.h>
  17
  18 #include "internals.h"
  19
  20 /*
  21  * Access rules:
  22  *
  23  * procfs protects read/write of /proc/irq/N/ files against a
  24  * concurrent free of the interrupt descriptor. remove_proc_entry()
  25  * immediately prevents new read/writes to happen and waits for
  26  * already running read/write functions to complete.
  27  *
  28  * We remove the proc entries first and then delete the interrupt
  29  * descriptor from the radix tree and free it. So it is guaranteed
  30  * that irq_to_desc(N) is valid as long as the read/writes are
  31  * permitted by procfs.
  32  *
  33  * The read from /proc/interrupts is a different problem because there
  34  * is no protection. So the lookup and the access to irqdesc
  35  * information must be protected by sparse_irq_lock.
  36  */
  37 static struct proc_dir_entry *root_irq_dir;
  38
  39 #ifdef CONFIG_SMP
  40
  41 enum {
  42         AFFINITY,
  43         AFFINITY_LIST,
  44         EFFECTIVE,
  45         EFFECTIVE_LIST,
  46 };
  47
  48 static int show_irq_affinity(int type, struct seq_file *m)
  49 {
  50         struct irq_desc *desc = irq_to_desc((long)m->private);
  51         const struct cpumask *mask;
  52
  53         switch (type) {
  54         case AFFINITY:
  55         case AFFINITY_LIST:
  56                 mask = desc->irq_common_data.affinity;
  57 #ifdef CONFIG_GENERIC_PENDING_IRQ
  58                 if (irqd_is_setaffinity_pending(&desc->irq_data))
  59                         mask = desc->pending_mask;
  60 #endif
  61                 break;
  62         case EFFECTIVE:
  63         case EFFECTIVE_LIST:
  64 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
  65                 mask = irq_data_get_effective_affinity_mask(&desc->irq_data);
  66                 break;
  67 #endif
  68         default:
  69                 return -EINVAL;
  70         }
  71
  72         switch (type) {
  73         case AFFINITY_LIST:
  74         case EFFECTIVE_LIST:
  75                 seq_printf(m, "%*pbl\n", cpumask_pr_args(mask));
  76                 break;
  77         case AFFINITY:
  78         case EFFECTIVE:
  79                 seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
  80                 break;
  81         }
  82         return 0;
  83 }
  84
  85 static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
  86 {
  87         struct irq_desc *desc = irq_to_desc((long)m->private);
  88         unsigned long flags;
  89         cpumask_var_t mask;
  90
  91         if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
  92                 return -ENOMEM;
  93
  94         raw_spin_lock_irqsave(&desc->lock, flags);
  95         if (desc->affinity_hint)
  96                 cpumask_copy(mask, desc->affinity_hint);
  97         raw_spin_unlock_irqrestore(&desc->lock, flags);
  98
  99         seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
 100         free_cpumask_var(mask);
 101
 102         return 0;
 103 }
 104
 105 #ifndef is_affinity_mask_valid
 106 #define is_affinity_mask_valid(val) 1
 107 #endif
 108
 109 int no_irq_affinity;
 110 static int irq_affinity_proc_show(struct seq_file *m, void *v)
 111 {
 112         return show_irq_affinity(AFFINITY, m);
 113 }
 114
 115 static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
 116 {
 117         return show_irq_affinity(AFFINITY_LIST, m);
 118 }
 119
 120
 121 static ssize_t write_irq_affinity(int type, struct file *file,
 122                 const char __user *buffer, size_t count, loff_t *pos)
 123 {
 124         unsigned int irq = (int)(long)PDE_DATA(file_inode(file));
 125         cpumask_var_t new_value;
 126         int err;
 127
 128         if (!irq_can_set_affinity_usr(irq) || no_irq_affinity)
 129                 return -EIO;
 130
 131         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 132                 return -ENOMEM;
 133
 134         if (type)
 135                 err = cpumask_parselist_user(buffer, count, new_value);
 136         else
 137                 err = cpumask_parse_user(buffer, count, new_value);
 138         if (err)
 139                 goto free_cpumask;
 140
 141         if (!is_affinity_mask_valid(new_value)) {
 142                 err = -EINVAL;
 143                 goto free_cpumask;
 144         }
 145
 146         /*
 147          * Do not allow disabling IRQs completely - it's a too easy
 148          * way to make the system unusable accidentally :-) At least
 149          * one online CPU still has to be targeted.
 150          */
 151         if (!cpumask_intersects(new_value, cpu_online_mask)) {
 152                 /*
 153                  * Special case for empty set - allow the architecture code
 154                  * to set default SMP affinity.
 155                  */
 156                 err = irq_select_affinity_usr(irq) ? -EINVAL : count;
 157         } else {
 158                 irq_set_affinity(irq, new_value);
 159                 err = count;
 160         }
 161
 162 free_cpumask:
 163         free_cpumask_var(new_value);
 164         return err;
 165 }
 166
 167 static ssize_t irq_affinity_proc_write(struct file *file,
 168                 const char __user *buffer, size_t count, loff_t *pos)
 169 {
 170         return write_irq_affinity(0, file, buffer, count, pos);
 171 }
 172
 173 static ssize_t irq_affinity_list_proc_write(struct file *file,
 174                 const char __user *buffer, size_t count, loff_t *pos)
 175 {
 176         return write_irq_affinity(1, file, buffer, count, pos);
 177 }
 178
 179 static int irq_affinity_proc_open(struct inode *inode, struct file *file)
 180 {
 181         return single_open(file, irq_affinity_proc_show, PDE_DATA(inode));
 182 }
 183
 184 static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
 185 {
 186         return single_open(file, irq_affinity_list_proc_show, PDE_DATA(inode));
 187 }
 188
 189 static int irq_affinity_hint_proc_open(struct inode *inode, struct file *file)
 190 {
 191         return single_open(file, irq_affinity_hint_proc_show, PDE_DATA(inode));
 192 }
 193
 194 static const struct file_operations irq_affinity_proc_fops = {
 195         .open           = irq_affinity_proc_open,
 196         .read           = seq_read,
 197         .llseek         = seq_lseek,
 198         .release        = single_release,
 199         .write          = irq_affinity_proc_write,
 200 };
 201
 202 static const struct file_operations irq_affinity_hint_proc_fops = {
 203         .open           = irq_affinity_hint_proc_open,
 204         .read           = seq_read,
 205         .llseek         = seq_lseek,
 206         .release        = single_release,
 207 };
 208
 209 static const struct file_operations irq_affinity_list_proc_fops = {
 210         .open           = irq_affinity_list_proc_open,
 211         .read           = seq_read,
 212         .llseek         = seq_lseek,
 213         .release        = single_release,
 214         .write          = irq_affinity_list_proc_write,
 215 };
 216
 217 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
 218 static int irq_effective_aff_proc_show(struct seq_file *m, void *v)
 219 {
 220         return show_irq_affinity(EFFECTIVE, m);
 221 }
 222
 223 static int irq_effective_aff_list_proc_show(struct seq_file *m, void *v)
 224 {
 225         return show_irq_affinity(EFFECTIVE_LIST, m);
 226 }
 227
 228 static int irq_effective_aff_proc_open(struct inode *inode, struct file *file)
 229 {
 230         return single_open(file, irq_effective_aff_proc_show, PDE_DATA(inode));
 231 }
 232
 233 static int irq_effective_aff_list_proc_open(struct inode *inode,
 234                                             struct file *file)
 235 {
 236         return single_open(file, irq_effective_aff_list_proc_show,
 237                            PDE_DATA(inode));
 238 }
 239
 240 static const struct file_operations irq_effective_aff_proc_fops = {
 241         .open           = irq_effective_aff_proc_open,
 242         .read           = seq_read,
 243         .llseek         = seq_lseek,
 244         .release        = single_release,
 245 };
 246
 247 static const struct file_operations irq_effective_aff_list_proc_fops = {
 248         .open           = irq_effective_aff_list_proc_open,
 249         .read           = seq_read,
 250         .llseek         = seq_lseek,
 251         .release        = single_release,
 252 };
 253 #endif
 254
 255 static int default_affinity_show(struct seq_file *m, void *v)
 256 {
 257         seq_printf(m, "%*pb\n", cpumask_pr_args(irq_default_affinity));
 258         return 0;
 259 }
 260
 261 static ssize_t default_affinity_write(struct file *file,
 262                 const char __user *buffer, size_t count, loff_t *ppos)
 263 {
 264         cpumask_var_t new_value;
 265         int err;
 266
 267         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 268                 return -ENOMEM;
 269
 270         err = cpumask_parse_user(buffer, count, new_value);
 271         if (err)
 272                 goto out;
 273
 274         if (!is_affinity_mask_valid(new_value)) {
 275                 err = -EINVAL;
 276                 goto out;
 277         }
 278
 279         /*
 280          * Do not allow disabling IRQs completely - it's a too easy
 281          * way to make the system unusable accidentally :-) At least
 282          * one online CPU still has to be targeted.
 283          */
 284         if (!cpumask_intersects(new_value, cpu_online_mask)) {
 285                 err = -EINVAL;
 286                 goto out;
 287         }
 288
 289         cpumask_copy(irq_default_affinity, new_value);
 290         err = count;
 291
 292 out:
 293         free_cpumask_var(new_value);
 294         return err;
 295 }
 296
 297 static int default_affinity_open(struct inode *inode, struct file *file)
 298 {
 299         return single_open(file, default_affinity_show, PDE_DATA(inode));
 300 }
 301
 302 static const struct file_operations default_affinity_proc_fops = {
 303         .open           = default_affinity_open,
 304         .read           = seq_read,
 305         .llseek         = seq_lseek,
 306         .release        = single_release,
 307         .write          = default_affinity_write,
 308 };
 309
 310 static int irq_node_proc_show(struct seq_file *m, void *v)
 311 {
 312         struct irq_desc *desc = irq_to_desc((long) m->private);
 313
 314         seq_printf(m, "%d\n", irq_desc_get_node(desc));
 315         return 0;
 316 }
 317
 318 static int irq_node_proc_open(struct inode *inode, struct file *file)
 319 {
 320         return single_open(file, irq_node_proc_show, PDE_DATA(inode));
 321 }
 322
 323 static const struct file_operations irq_node_proc_fops = {
 324         .open           = irq_node_proc_open,
 325         .read           = seq_read,
 326         .llseek         = seq_lseek,
 327         .release        = single_release,
 328 };
 329 #endif
 330
 331 static int irq_spurious_proc_show(struct seq_file *m, void *v)
 332 {
 333         struct irq_desc *desc = irq_to_desc((long) m->private);
 334
 335         seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
 336                    desc->irq_count, desc->irqs_unhandled,
 337                    jiffies_to_msecs(desc->last_unhandled));
 338         return 0;
 339 }
 340
 341 static int irq_spurious_proc_open(struct inode *inode, struct file *file)
 342 {
 343         return single_open(file, irq_spurious_proc_show, PDE_DATA(inode));
 344 }
 345
 346 static const struct file_operations irq_spurious_proc_fops = {
 347         .open           = irq_spurious_proc_open,
 348         .read           = seq_read,
 349         .llseek         = seq_lseek,
 350         .release        = single_release,
 351 };
 352
 353 #define MAX_NAMELEN 128
 354
 355 static int name_unique(unsigned int irq, struct irqaction *new_action)
 356 {
 357         struct irq_desc *desc = irq_to_desc(irq);
 358         struct irqaction *action;
 359         unsigned long flags;
 360         int ret = 1;
 361
 362         raw_spin_lock_irqsave(&desc->lock, flags);
 363         for_each_action_of_desc(desc, action) {
 364                 if ((action != new_action) && action->name &&
 365                                 !strcmp(new_action->name, action->name)) {
 366                         ret = 0;
 367                         break;
 368                 }
 369         }
 370         raw_spin_unlock_irqrestore(&desc->lock, flags);
 371         return ret;
 372 }
 373
 374 void register_handler_proc(unsigned int irq, struct irqaction *action)
 375 {
 376         char name [MAX_NAMELEN];
 377         struct irq_desc *desc = irq_to_desc(irq);
 378
 379         if (!desc->dir || action->dir || !action->name ||
 380                                         !name_unique(irq, action))
 381                 return;
 382
 383         snprintf(name, MAX_NAMELEN, "%s", action->name);
 384
 385         /* create /proc/irq/1234/handler/ */
 386         action->dir = proc_mkdir(name, desc->dir);
 387 }
 388
 389 #undef MAX_NAMELEN
 390
 391 #define MAX_NAMELEN 10
 392
 393 void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 394 {
 395         static DEFINE_MUTEX(register_lock);
 396         void __maybe_unused *irqp = (void *)(unsigned long) irq;
 397         char name [MAX_NAMELEN];
 398
 399         if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
 400                 return;
 401
 402         /*
 403          * irq directories are registered only when a handler is
 404          * added, not when the descriptor is created, so multiple
 405          * tasks might try to register at the same time.
 406          */
 407         mutex_lock(&register_lock);
 408
 409         if (desc->dir)
 410                 goto out_unlock;
 411
 412         sprintf(name, "%d", irq);
 413
 414         /* create /proc/irq/1234 */
 415         desc->dir = proc_mkdir(name, root_irq_dir);
 416         if (!desc->dir)
 417                 goto out_unlock;
 418
 419 #ifdef CONFIG_SMP
 420         /* create /proc/irq/<irq>/smp_affinity */
 421         proc_create_data("smp_affinity", 0644, desc->dir,
 422                          &irq_affinity_proc_fops, irqp);
 423
 424         /* create /proc/irq/<irq>/affinity_hint */
 425         proc_create_data("affinity_hint", 0444, desc->dir,
 426                          &irq_affinity_hint_proc_fops, irqp);
 427
 428         /* create /proc/irq/<irq>/smp_affinity_list */
 429         proc_create_data("smp_affinity_list", 0644, desc->dir,
 430                          &irq_affinity_list_proc_fops, irqp);
 431
 432         proc_create_data("node", 0444, desc->dir,
 433                          &irq_node_proc_fops, irqp);
 434 # ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
 435         proc_create_data("effective_affinity", 0444, desc->dir,
 436                          &irq_effective_aff_proc_fops, irqp);
 437         proc_create_data("effective_affinity_list", 0444, desc->dir,
 438                          &irq_effective_aff_list_proc_fops, irqp);
 439 # endif
 440 #endif
 441         proc_create_data("spurious", 0444, desc->dir,
 442                          &irq_spurious_proc_fops, (void *)(long)irq);
 443
 444 out_unlock:
 445         mutex_unlock(&register_lock);
 446 }
 447
 448 void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
 449 {
 450         char name [MAX_NAMELEN];
 451
 452         if (!root_irq_dir || !desc->dir)
 453                 return;
 454 #ifdef CONFIG_SMP
 455         remove_proc_entry("smp_affinity", desc->dir);
 456         remove_proc_entry("affinity_hint", desc->dir);
 457         remove_proc_entry("smp_affinity_list", desc->dir);
 458         remove_proc_entry("node", desc->dir);
 459 # ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
 460         remove_proc_entry("effective_affinity", desc->dir);
 461         remove_proc_entry("effective_affinity_list", desc->dir);
 462 # endif
 463 #endif
 464         remove_proc_entry("spurious", desc->dir);
 465
 466         sprintf(name, "%u", irq);
 467         remove_proc_entry(name, root_irq_dir);
 468 }
 469
 470 #undef MAX_NAMELEN
 471
 472 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 473 {
 474         proc_remove(action->dir);
 475 }
 476
 477 static void register_default_affinity_proc(void)
 478 {
 479 #ifdef CONFIG_SMP
 480         proc_create("irq/default_smp_affinity", 0644, NULL,
 481                     &default_affinity_proc_fops);
 482 #endif
 483 }
 484
 485 void init_irq_proc(void)
 486 {
 487         unsigned int irq;
 488         struct irq_desc *desc;
 489
 490         /* create /proc/irq */
 491         root_irq_dir = proc_mkdir("irq", NULL);
 492         if (!root_irq_dir)
 493                 return;
 494
 495         register_default_affinity_proc();
 496
 497         /*
 498          * Create entries for all existing IRQs.
 499          */
 500         for_each_irq_desc(irq, desc)
 501                 register_irq_proc(irq, desc);
 502 }
 503
 504 #ifdef CONFIG_GENERIC_IRQ_SHOW
 505
 506 int __weak arch_show_interrupts(struct seq_file *p, int prec)
 507 {
 508         return 0;
 509 }
 510
 511 #ifndef ACTUAL_NR_IRQS
 512 # define ACTUAL_NR_IRQS nr_irqs
 513 #endif
 514
 515 int show_interrupts(struct seq_file *p, void *v)
 516 {
 517         static int prec;
 518
 519         unsigned long flags, any_count = 0;
 520         int i = *(loff_t *) v, j;
 521         struct irqaction *action;
 522         struct irq_desc *desc;
 523
 524         if (i > ACTUAL_NR_IRQS)
 525                 return 0;
 526
 527         if (i == ACTUAL_NR_IRQS)
 528                 return arch_show_interrupts(p, prec);
 529
 530         /* print header and calculate the width of the first column */
 531         if (i == 0) {
 532                 for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
 533                         j *= 10;
 534
 535                 seq_printf(p, "%*s", prec + 8, "");
 536                 for_each_online_cpu(j)
 537                         seq_printf(p, "CPU%-8d", j);
 538                 seq_putc(p, '\n');
 539         }
 540
 541         irq_lock_sparse();
 542         desc = irq_to_desc(i);
 543         if (!desc)
 544                 goto outsparse;
 545
 546         raw_spin_lock_irqsave(&desc->lock, flags);
 547         for_each_online_cpu(j)
 548                 any_count |= kstat_irqs_cpu(i, j);
 549         action = desc->action;
 550         if ((!action || irq_desc_is_chained(desc)) && !any_count)
 551                 goto out;
 552
 553         seq_printf(p, "%*d: ", prec, i);
 554         for_each_online_cpu(j)
 555                 seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
 556
 557         if (desc->irq_data.chip) {
 558                 if (desc->irq_data.chip->irq_print_chip)
 559                         desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
 560                 else if (desc->irq_data.chip->name)
 561                         seq_printf(p, " %8s", desc->irq_data.chip->name);
 562                 else
 563                         seq_printf(p, " %8s", "-");
 564         } else {
 565                 seq_printf(p, " %8s", "None");
 566         }
 567         if (desc->irq_data.domain)
 568                 seq_printf(p, " %*d", prec, (int) desc->irq_data.hwirq);
 569         else
 570                 seq_printf(p, " %*s", prec, "");
 571 #ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
 572         seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
 573 #endif
 574         if (desc->name)
 575                 seq_printf(p, "-%-8s", desc->name);
 576
 577         if (action) {
 578                 seq_printf(p, "  %s", action->name);
 579                 while ((action = action->next) != NULL)
 580                         seq_printf(p, ", %s", action->name);
 581         }
 582
 583         seq_putc(p, '\n');
 584 out:
 585         raw_spin_unlock_irqrestore(&desc->lock, flags);
 586 outsparse:
 587         irq_unlock_sparse();
 588         return 0;
 589 }
 590 #endif