kernel/irq/proc.c

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