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 #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
  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;
 104 static int irq_affinity_proc_show(struct seq_file *m, void *v)
 105 {
 106         return show_irq_affinity(AFFINITY, m);
 107 }
 108
 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
 115 static ssize_t write_irq_affinity(int type, struct file *file,
 116                 const char __user *buffer, size_t count, loff_t *pos)
 117 {
 118         unsigned int irq = (int)(long)PDE_DATA(file_inode(file));
 119         cpumask_var_t new_value;
 120         int err;
 121
 122         if (!irq_can_set_affinity_usr(irq) || no_irq_affinity)
 123                 return -EIO;
 124
 125         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 126                 return -ENOMEM;
 127
 128         if (type)
 129                 err = cpumask_parselist_user(buffer, count, new_value);
 130         else
 131                 err = cpumask_parse_user(buffer, count, new_value);
 132         if (err)
 133                 goto free_cpumask;
 134
 135         /*
 136          * Do not allow disabling IRQs completely - it's a too easy
 137          * way to make the system unusable accidentally :-) At least
 138          * one online CPU still has to be targeted.
 139          */
 140         if (!cpumask_intersects(new_value, cpu_online_mask)) {
 141                 /*
 142                  * Special case for empty set - allow the architecture code
 143                  * to set default SMP affinity.
 144                  */
 145                 err = irq_select_affinity_usr(irq) ? -EINVAL : count;
 146         } else {
 147                 err = irq_set_affinity(irq, new_value);
 148                 if (!err)
 149                         err = count;
 150         }
 151
 152 free_cpumask:
 153         free_cpumask_var(new_value);
 154         return err;
 155 }
 156
 157 static ssize_t irq_affinity_proc_write(struct file *file,
 158                 const char __user *buffer, size_t count, loff_t *pos)
 159 {
 160         return write_irq_affinity(0, file, buffer, count, pos);
 161 }
 162
 163 static ssize_t irq_affinity_list_proc_write(struct file *file,
 164                 const char __user *buffer, size_t count, loff_t *pos)
 165 {
 166         return write_irq_affinity(1, file, buffer, count, pos);
 167 }
 168
 169 static int irq_affinity_proc_open(struct inode *inode, struct file *file)
 170 {
 171         return single_open(file, irq_affinity_proc_show, PDE_DATA(inode));
 172 }
 173
 174 static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
 175 {
 176         return single_open(file, irq_affinity_list_proc_show, PDE_DATA(inode));
 177 }
 178
 179 static const struct file_operations irq_affinity_proc_fops = {
 180         .open           = irq_affinity_proc_open,
 181         .read           = seq_read,
 182         .llseek         = seq_lseek,
 183         .release        = single_release,
 184         .write          = irq_affinity_proc_write,
 185 };
 186
 187 static const struct file_operations irq_affinity_list_proc_fops = {
 188         .open           = irq_affinity_list_proc_open,
 189         .read           = seq_read,
 190         .llseek         = seq_lseek,
 191         .release        = single_release,
 192         .write          = irq_affinity_list_proc_write,
 193 };
 194
 195 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
 196 static int irq_effective_aff_proc_show(struct seq_file *m, void *v)
 197 {
 198         return show_irq_affinity(EFFECTIVE, m);
 199 }
 200
 201 static int irq_effective_aff_list_proc_show(struct seq_file *m, void *v)
 202 {
 203         return show_irq_affinity(EFFECTIVE_LIST, m);
 204 }
 205 #endif
 206
 207 static int default_affinity_show(struct seq_file *m, void *v)
 208 {
 209         seq_printf(m, "%*pb\n", cpumask_pr_args(irq_default_affinity));
 210         return 0;
 211 }
 212
 213 static ssize_t default_affinity_write(struct file *file,
 214                 const char __user *buffer, size_t count, loff_t *ppos)
 215 {
 216         cpumask_var_t new_value;
 217         int err;
 218
 219         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 220                 return -ENOMEM;
 221
 222         err = cpumask_parse_user(buffer, count, new_value);
 223         if (err)
 224                 goto out;
 225
 226         /*
 227          * Do not allow disabling IRQs completely - it's a too easy
 228          * way to make the system unusable accidentally :-) At least
 229          * one online CPU still has to be targeted.
 230          */
 231         if (!cpumask_intersects(new_value, cpu_online_mask)) {
 232                 err = -EINVAL;
 233                 goto out;
 234         }
 235
 236         cpumask_copy(irq_default_affinity, new_value);
 237         err = count;
 238
 239 out:
 240         free_cpumask_var(new_value);
 241         return err;
 242 }
 243
 244 static int default_affinity_open(struct inode *inode, struct file *file)
 245 {
 246         return single_open(file, default_affinity_show, PDE_DATA(inode));
 247 }
 248
 249 static const struct file_operations default_affinity_proc_fops = {
 250         .open           = default_affinity_open,
 251         .read           = seq_read,
 252         .llseek         = seq_lseek,
 253         .release        = single_release,
 254         .write          = default_affinity_write,
 255 };
 256
 257 static int irq_node_proc_show(struct seq_file *m, void *v)
 258 {
 259         struct irq_desc *desc = irq_to_desc((long) m->private);
 260
 261         seq_printf(m, "%d\n", irq_desc_get_node(desc));
 262         return 0;
 263 }
 264 #endif
 265
 266 static int irq_spurious_proc_show(struct seq_file *m, void *v)
 267 {
 268         struct irq_desc *desc = irq_to_desc((long) m->private);
 269
 270         seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
 271                    desc->irq_count, desc->irqs_unhandled,
 272                    jiffies_to_msecs(desc->last_unhandled));
 273         return 0;
 274 }
 275
 276 #define MAX_NAMELEN 128
 277
 278 static int name_unique(unsigned int irq, struct irqaction *new_action)
 279 {
 280         struct irq_desc *desc = irq_to_desc(irq);
 281         struct irqaction *action;
 282         unsigned long flags;
 283         int ret = 1;
 284
 285         raw_spin_lock_irqsave(&desc->lock, flags);
 286         for_each_action_of_desc(desc, action) {
 287                 if ((action != new_action) && action->name &&
 288                                 !strcmp(new_action->name, action->name)) {
 289                         ret = 0;
 290                         break;
 291                 }
 292         }
 293         raw_spin_unlock_irqrestore(&desc->lock, flags);
 294         return ret;
 295 }
 296
 297 void register_handler_proc(unsigned int irq, struct irqaction *action)
 298 {
 299         char name [MAX_NAMELEN];
 300         struct irq_desc *desc = irq_to_desc(irq);
 301
 302         if (!desc->dir || action->dir || !action->name ||
 303                                         !name_unique(irq, action))
 304                 return;
 305
 306         snprintf(name, MAX_NAMELEN, "%s", action->name);
 307
 308         /* create /proc/irq/1234/handler/ */
 309         action->dir = proc_mkdir(name, desc->dir);
 310 }
 311
 312 #undef MAX_NAMELEN
 313
 314 #define MAX_NAMELEN 10
 315
 316 void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 317 {
 318         static DEFINE_MUTEX(register_lock);
 319         void __maybe_unused *irqp = (void *)(unsigned long) irq;
 320         char name [MAX_NAMELEN];
 321
 322         if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
 323                 return;
 324
 325         /*
 326          * irq directories are registered only when a handler is
 327          * added, not when the descriptor is created, so multiple
 328          * tasks might try to register at the same time.
 329          */
 330         mutex_lock(&register_lock);
 331
 332         if (desc->dir)
 333                 goto out_unlock;
 334
 335         sprintf(name, "%d", irq);
 336
 337         /* create /proc/irq/1234 */
 338         desc->dir = proc_mkdir(name, root_irq_dir);
 339         if (!desc->dir)
 340                 goto out_unlock;
 341
 342 #ifdef CONFIG_SMP
 343         /* create /proc/irq/<irq>/smp_affinity */
 344         proc_create_data("smp_affinity", 0644, desc->dir,
 345                          &irq_affinity_proc_fops, irqp);
 346
 347         /* create /proc/irq/<irq>/affinity_hint */
 348         proc_create_single_data("affinity_hint", 0444, desc->dir,
 349                         irq_affinity_hint_proc_show, irqp);
 350
 351         /* create /proc/irq/<irq>/smp_affinity_list */
 352         proc_create_data("smp_affinity_list", 0644, desc->dir,
 353                          &irq_affinity_list_proc_fops, irqp);
 354
 355         proc_create_single_data("node", 0444, desc->dir, irq_node_proc_show,
 356                         irqp);
 357 # ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
 358         proc_create_single_data("effective_affinity", 0444, desc->dir,
 359                         irq_effective_aff_proc_show, irqp);
 360         proc_create_single_data("effective_affinity_list", 0444, desc->dir,
 361                         irq_effective_aff_list_proc_show, irqp);
 362 # endif
 363 #endif
 364         proc_create_single_data("spurious", 0444, desc->dir,
 365                         irq_spurious_proc_show, (void *)(long)irq);
 366
 367 out_unlock:
 368         mutex_unlock(&register_lock);
 369 }
 370
 371 void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
 372 {
 373         char name [MAX_NAMELEN];
 374
 375         if (!root_irq_dir || !desc->dir)
 376                 return;
 377 #ifdef CONFIG_SMP
 378         remove_proc_entry("smp_affinity", desc->dir);
 379         remove_proc_entry("affinity_hint", desc->dir);
 380         remove_proc_entry("smp_affinity_list", desc->dir);
 381         remove_proc_entry("node", desc->dir);
 382 # ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
 383         remove_proc_entry("effective_affinity", desc->dir);
 384         remove_proc_entry("effective_affinity_list", desc->dir);
 385 # endif
 386 #endif
 387         remove_proc_entry("spurious", desc->dir);
 388
 389         sprintf(name, "%u", irq);
 390         remove_proc_entry(name, root_irq_dir);
 391 }
 392
 393 #undef MAX_NAMELEN
 394
 395 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 396 {
 397         proc_remove(action->dir);
 398 }
 399
 400 static void register_default_affinity_proc(void)
 401 {
 402 #ifdef CONFIG_SMP
 403         proc_create("irq/default_smp_affinity", 0644, NULL,
 404                     &default_affinity_proc_fops);
 405 #endif
 406 }
 407
 408 void init_irq_proc(void)
 409 {
 410         unsigned int irq;
 411         struct irq_desc *desc;
 412
 413         /* create /proc/irq */
 414         root_irq_dir = proc_mkdir("irq", NULL);
 415         if (!root_irq_dir)
 416                 return;
 417
 418         register_default_affinity_proc();
 419
 420         /*
 421          * Create entries for all existing IRQs.
 422          */
 423         for_each_irq_desc(irq, desc)
 424                 register_irq_proc(irq, desc);
 425 }
 426
 427 #ifdef CONFIG_GENERIC_IRQ_SHOW
 428
 429 int __weak arch_show_interrupts(struct seq_file *p, int prec)
 430 {
 431         return 0;
 432 }
 433
 434 #ifndef ACTUAL_NR_IRQS
 435 # define ACTUAL_NR_IRQS nr_irqs
 436 #endif
 437
 438 int show_interrupts(struct seq_file *p, void *v)
 439 {
 440         static int prec;
 441
 442         unsigned long flags, any_count = 0;
 443         int i = *(loff_t *) v, j;
 444         struct irqaction *action;
 445         struct irq_desc *desc;
 446
 447         if (i > ACTUAL_NR_IRQS)
 448                 return 0;
 449
 450         if (i == ACTUAL_NR_IRQS)
 451                 return arch_show_interrupts(p, prec);
 452
 453         /* print header and calculate the width of the first column */
 454         if (i == 0) {
 455                 for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
 456                         j *= 10;
 457
 458                 seq_printf(p, "%*s", prec + 8, "");
 459                 for_each_online_cpu(j)
 460                         seq_printf(p, "CPU%-8d", j);
 461                 seq_putc(p, '\n');
 462         }
 463
 464         rcu_read_lock();
 465         desc = irq_to_desc(i);
 466         if (!desc)
 467                 goto outsparse;
 468
 469         if (desc->kstat_irqs)
 470                 for_each_online_cpu(j)
 471                         any_count |= *per_cpu_ptr(desc->kstat_irqs, j);
 472
 473         if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
 474                 goto outsparse;
 475
 476         seq_printf(p, "%*d: ", prec, i);
 477         for_each_online_cpu(j)
 478                 seq_printf(p, "%10u ", desc->kstat_irqs ?
 479                                         *per_cpu_ptr(desc->kstat_irqs, j) : 0);
 480
 481         raw_spin_lock_irqsave(&desc->lock, flags);
 482         if (desc->irq_data.chip) {
 483                 if (desc->irq_data.chip->irq_print_chip)
 484                         desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
 485                 else if (desc->irq_data.chip->name)
 486                         seq_printf(p, " %8s", desc->irq_data.chip->name);
 487                 else
 488                         seq_printf(p, " %8s", "-");
 489         } else {
 490                 seq_printf(p, " %8s", "None");
 491         }
 492         if (desc->irq_data.domain)
 493                 seq_printf(p, " %*d", prec, (int) desc->irq_data.hwirq);
 494         else
 495                 seq_printf(p, " %*s", prec, "");
 496 #ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
 497         seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
 498 #endif
 499         if (desc->name)
 500                 seq_printf(p, "-%-8s", desc->name);
 501
 502         action = desc->action;
 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         raw_spin_unlock_irqrestore(&desc->lock, flags);
 511 outsparse:
 512         rcu_read_unlock();
 513         return 0;
 514 }
 515 #endif