kernel/irq/proc.c

   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
  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 static int show_irq_affinity(int type, struct seq_file *m, void *v)
  40 {
  41         struct irq_desc *desc = irq_to_desc((long)m->private);
  42         const struct cpumask *mask = desc->irq_data.affinity;
  43
  44 #ifdef CONFIG_GENERIC_PENDING_IRQ
  45         if (irqd_is_setaffinity_pending(&desc->irq_data))
  46                 mask = desc->pending_mask;
  47 #endif
  48         if (type)
  49                 seq_cpumask_list(m, mask);
  50         else
  51                 seq_cpumask(m, mask);
  52         seq_putc(m, '\n');
  53         return 0;
  54 }
  55
  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_cpumask(m, mask);
  71         seq_putc(m, '\n');
  72         free_cpumask_var(mask);
  73
  74         return 0;
  75 }
  76
  77 #ifndef is_affinity_mask_valid
  78 #define is_affinity_mask_valid(val) 1
  79 #endif
  80
  81 int no_irq_affinity;
  82 static int irq_affinity_proc_show(struct seq_file *m, void *v)
  83 {
  84         return show_irq_affinity(0, m, v);
  85 }
  86
  87 static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
  88 {
  89         return show_irq_affinity(1, m, v);
  90 }
  91
  92
  93 static ssize_t write_irq_affinity(int type, struct file *file,
  94                 const char __user *buffer, size_t count, loff_t *pos)
  95 {
  96         unsigned int irq = (int)(long)PDE(file->f_path.dentry->d_inode)->data;
  97         cpumask_var_t new_value;
  98         int err;
  99
 100         if (!irq_can_set_affinity(irq) || no_irq_affinity)
 101                 return -EIO;
 102
 103         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 104                 return -ENOMEM;
 105
 106         if (type)
 107                 err = cpumask_parselist_user(buffer, count, new_value);
 108         else
 109                 err = cpumask_parse_user(buffer, count, new_value);
 110         if (err)
 111                 goto free_cpumask;
 112
 113         if (!is_affinity_mask_valid(new_value)) {
 114                 err = -EINVAL;
 115                 goto free_cpumask;
 116         }
 117
 118         /*
 119          * Do not allow disabling IRQs completely - it's a too easy
 120          * way to make the system unusable accidentally :-) At least
 121          * one online CPU still has to be targeted.
 122          */
 123         if (!cpumask_intersects(new_value, cpu_online_mask)) {
 124                 /* Special case for empty set - allow the architecture
 125                    code to set default SMP affinity. */
 126                 err = irq_select_affinity_usr(irq, new_value) ? -EINVAL : count;
 127         } else {
 128                 irq_set_affinity(irq, new_value);
 129                 err = count;
 130         }
 131
 132 free_cpumask:
 133         free_cpumask_var(new_value);
 134         return err;
 135 }
 136
 137 static ssize_t irq_affinity_proc_write(struct file *file,
 138                 const char __user *buffer, size_t count, loff_t *pos)
 139 {
 140         return write_irq_affinity(0, file, buffer, count, pos);
 141 }
 142
 143 static ssize_t irq_affinity_list_proc_write(struct file *file,
 144                 const char __user *buffer, size_t count, loff_t *pos)
 145 {
 146         return write_irq_affinity(1, file, buffer, count, pos);
 147 }
 148
 149 static int irq_affinity_proc_open(struct inode *inode, struct file *file)
 150 {
 151         return single_open(file, irq_affinity_proc_show, PDE(inode)->data);
 152 }
 153
 154 static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
 155 {
 156         return single_open(file, irq_affinity_list_proc_show, PDE(inode)->data);
 157 }
 158
 159 static int irq_affinity_hint_proc_open(struct inode *inode, struct file *file)
 160 {
 161         return single_open(file, irq_affinity_hint_proc_show, PDE(inode)->data);
 162 }
 163
 164 static const struct file_operations irq_affinity_proc_fops = {
 165         .open           = irq_affinity_proc_open,
 166         .read           = seq_read,
 167         .llseek         = seq_lseek,
 168         .release        = single_release,
 169         .write          = irq_affinity_proc_write,
 170 };
 171
 172 static const struct file_operations irq_affinity_hint_proc_fops = {
 173         .open           = irq_affinity_hint_proc_open,
 174         .read           = seq_read,
 175         .llseek         = seq_lseek,
 176         .release        = single_release,
 177 };
 178
 179 static const struct file_operations irq_affinity_list_proc_fops = {
 180         .open           = irq_affinity_list_proc_open,
 181         .read           = seq_read,
 182         .llseek         = seq_lseek,
 183         .release        = single_release,
 184         .write          = irq_affinity_list_proc_write,
 185 };
 186
 187 static int default_affinity_show(struct seq_file *m, void *v)
 188 {
 189         seq_cpumask(m, irq_default_affinity);
 190         seq_putc(m, '\n');
 191         return 0;
 192 }
 193
 194 static ssize_t default_affinity_write(struct file *file,
 195                 const char __user *buffer, size_t count, loff_t *ppos)
 196 {
 197         cpumask_var_t new_value;
 198         int err;
 199
 200         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
 201                 return -ENOMEM;
 202
 203         err = cpumask_parse_user(buffer, count, new_value);
 204         if (err)
 205                 goto out;
 206
 207         if (!is_affinity_mask_valid(new_value)) {
 208                 err = -EINVAL;
 209                 goto out;
 210         }
 211
 212         /*
 213          * Do not allow disabling IRQs completely - it's a too easy
 214          * way to make the system unusable accidentally :-) At least
 215          * one online CPU still has to be targeted.
 216          */
 217         if (!cpumask_intersects(new_value, cpu_online_mask)) {
 218                 err = -EINVAL;
 219                 goto out;
 220         }
 221
 222         cpumask_copy(irq_default_affinity, new_value);
 223         err = count;
 224
 225 out:
 226         free_cpumask_var(new_value);
 227         return err;
 228 }
 229
 230 static int default_affinity_open(struct inode *inode, struct file *file)
 231 {
 232         return single_open(file, default_affinity_show, PDE(inode)->data);
 233 }
 234
 235 static const struct file_operations default_affinity_proc_fops = {
 236         .open           = default_affinity_open,
 237         .read           = seq_read,
 238         .llseek         = seq_lseek,
 239         .release        = single_release,
 240         .write          = default_affinity_write,
 241 };
 242
 243 static int irq_node_proc_show(struct seq_file *m, void *v)
 244 {
 245         struct irq_desc *desc = irq_to_desc((long) m->private);
 246
 247         seq_printf(m, "%d\n", desc->irq_data.node);
 248         return 0;
 249 }
 250
 251 static int irq_node_proc_open(struct inode *inode, struct file *file)
 252 {
 253         return single_open(file, irq_node_proc_show, PDE(inode)->data);
 254 }
 255
 256 static const struct file_operations irq_node_proc_fops = {
 257         .open           = irq_node_proc_open,
 258         .read           = seq_read,
 259         .llseek         = seq_lseek,
 260         .release        = single_release,
 261 };
 262 #endif
 263
 264 static int irq_spurious_proc_show(struct seq_file *m, void *v)
 265 {
 266         struct irq_desc *desc = irq_to_desc((long) m->private);
 267
 268         seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
 269                    desc->irq_count, desc->irqs_unhandled,
 270                    jiffies_to_msecs(desc->last_unhandled));
 271         return 0;
 272 }
 273
 274 static int irq_spurious_proc_open(struct inode *inode, struct file *file)
 275 {
 276         return single_open(file, irq_spurious_proc_show, PDE(inode)->data);
 277 }
 278
 279 static const struct file_operations irq_spurious_proc_fops = {
 280         .open           = irq_spurious_proc_open,
 281         .read           = seq_read,
 282         .llseek         = seq_lseek,
 283         .release        = single_release,
 284 };
 285
 286 #define MAX_NAMELEN 128
 287
 288 static int name_unique(unsigned int irq, struct irqaction *new_action)
 289 {
 290         struct irq_desc *desc = irq_to_desc(irq);
 291         struct irqaction *action;
 292         unsigned long flags;
 293         int ret = 1;
 294
 295         raw_spin_lock_irqsave(&desc->lock, flags);
 296         for (action = desc->action ; action; action = action->next) {
 297                 if ((action != new_action) && action->name &&
 298                                 !strcmp(new_action->name, action->name)) {
 299                         ret = 0;
 300                         break;
 301                 }
 302         }
 303         raw_spin_unlock_irqrestore(&desc->lock, flags);
 304         return ret;
 305 }
 306
 307 void register_handler_proc(unsigned int irq, struct irqaction *action)
 308 {
 309         char name [MAX_NAMELEN];
 310         struct irq_desc *desc = irq_to_desc(irq);
 311
 312         if (!desc->dir || action->dir || !action->name ||
 313                                         !name_unique(irq, action))
 314                 return;
 315
 316         memset(name, 0, MAX_NAMELEN);
 317         snprintf(name, MAX_NAMELEN, "%s", action->name);
 318
 319         /* create /proc/irq/1234/handler/ */
 320         action->dir = proc_mkdir(name, desc->dir);
 321 }
 322
 323 #undef MAX_NAMELEN
 324
 325 #define MAX_NAMELEN 10
 326
 327 void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 328 {
 329         char name [MAX_NAMELEN];
 330
 331         if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip) || desc->dir)
 332                 return;
 333
 334         memset(name, 0, MAX_NAMELEN);
 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                 return;
 341
 342 #ifdef CONFIG_SMP
 343         /* create /proc/irq/<irq>/smp_affinity */
 344         proc_create_data("smp_affinity", 0600, desc->dir,
 345                          &irq_affinity_proc_fops, (void *)(long)irq);
 346
 347         /* create /proc/irq/<irq>/affinity_hint */
 348         proc_create_data("affinity_hint", 0400, desc->dir,
 349                          &irq_affinity_hint_proc_fops, (void *)(long)irq);
 350
 351         /* create /proc/irq/<irq>/smp_affinity_list */
 352         proc_create_data("smp_affinity_list", 0600, desc->dir,
 353                          &irq_affinity_list_proc_fops, (void *)(long)irq);
 354
 355         proc_create_data("node", 0444, desc->dir,
 356                          &irq_node_proc_fops, (void *)(long)irq);
 357 #endif
 358
 359         proc_create_data("spurious", 0444, desc->dir,
 360                          &irq_spurious_proc_fops, (void *)(long)irq);
 361 }
 362
 363 void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
 364 {
 365         char name [MAX_NAMELEN];
 366
 367         if (!root_irq_dir || !desc->dir)
 368                 return;
 369 #ifdef CONFIG_SMP
 370         remove_proc_entry("smp_affinity", desc->dir);
 371         remove_proc_entry("affinity_hint", desc->dir);
 372         remove_proc_entry("smp_affinity_list", desc->dir);
 373         remove_proc_entry("node", desc->dir);
 374 #endif
 375         remove_proc_entry("spurious", desc->dir);
 376
 377         memset(name, 0, MAX_NAMELEN);
 378         sprintf(name, "%u", irq);
 379         remove_proc_entry(name, root_irq_dir);
 380 }
 381
 382 #undef MAX_NAMELEN
 383
 384 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
 385 {
 386         if (action->dir) {
 387                 struct irq_desc *desc = irq_to_desc(irq);
 388
 389                 remove_proc_entry(action->dir->name, desc->dir);
 390         }
 391 }
 392
 393 static void register_default_affinity_proc(void)
 394 {
 395 #ifdef CONFIG_SMP
 396         proc_create("irq/default_smp_affinity", 0600, NULL,
 397                     &default_affinity_proc_fops);
 398 #endif
 399 }
 400
 401 void init_irq_proc(void)
 402 {
 403         unsigned int irq;
 404         struct irq_desc *desc;
 405
 406         /* create /proc/irq */
 407         root_irq_dir = proc_mkdir("irq", NULL);
 408         if (!root_irq_dir)
 409                 return;
 410
 411         register_default_affinity_proc();
 412
 413         /*
 414          * Create entries for all existing IRQs.
 415          */
 416         for_each_irq_desc(irq, desc) {
 417                 if (!desc)
 418                         continue;
 419
 420                 register_irq_proc(irq, desc);
 421         }
 422 }
 423
 424 #ifdef CONFIG_GENERIC_IRQ_SHOW
 425
 426 int __weak arch_show_interrupts(struct seq_file *p, int prec)
 427 {
 428         return 0;
 429 }
 430
 431 #ifndef ACTUAL_NR_IRQS
 432 # define ACTUAL_NR_IRQS nr_irqs
 433 #endif
 434
 435 int show_interrupts(struct seq_file *p, void *v)
 436 {
 437         static int prec;
 438
 439         unsigned long flags, any_count = 0;
 440         int i = *(loff_t *) v, j;
 441         struct irqaction *action;
 442         struct irq_desc *desc;
 443
 444         if (i > ACTUAL_NR_IRQS)
 445                 return 0;
 446
 447         if (i == ACTUAL_NR_IRQS)
 448                 return arch_show_interrupts(p, prec);
 449
 450         /* print header and calculate the width of the first column */
 451         if (i == 0) {
 452                 for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
 453                         j *= 10;
 454
 455                 seq_printf(p, "%*s", prec + 8, "");
 456                 for_each_online_cpu(j)
 457                         seq_printf(p, "CPU%-8d", j);
 458                 seq_putc(p, '\n');
 459         }
 460
 461         irq_lock_sparse();
 462         desc = irq_to_desc(i);
 463         if (!desc)
 464                 goto outsparse;
 465
 466         raw_spin_lock_irqsave(&desc->lock, flags);
 467         for_each_online_cpu(j)
 468                 any_count |= kstat_irqs_cpu(i, j);
 469         action = desc->action;
 470         if (!action && !any_count)
 471                 goto out;
 472
 473         seq_printf(p, "%*d: ", prec, i);
 474         for_each_online_cpu(j)
 475                 seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
 476
 477         if (desc->irq_data.chip) {
 478                 if (desc->irq_data.chip->irq_print_chip)
 479                         desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
 480                 else if (desc->irq_data.chip->name)
 481                         seq_printf(p, " %8s", desc->irq_data.chip->name);
 482                 else
 483                         seq_printf(p, " %8s", "-");
 484         } else {
 485                 seq_printf(p, " %8s", "None");
 486         }
 487 #ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
 488         seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
 489 #endif
 490         if (desc->name)
 491                 seq_printf(p, "-%-8s", desc->name);
 492
 493         if (action) {
 494                 seq_printf(p, "  %s", action->name);
 495                 while ((action = action->next) != NULL)
 496                         seq_printf(p, ", %s", action->name);
 497         }
 498
 499         seq_putc(p, '\n');
 500 out:
 501         raw_spin_unlock_irqrestore(&desc->lock, flags);
 502 outsparse:
 503         irq_unlock_sparse();
 504         return 0;
 505 }
 506 #endif