kernel/irq/manage.c

   1 /*
   2  * linux/kernel/irq/manage.c
   3  *
   4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   5  * Copyright (C) 2005-2006 Thomas Gleixner
   6  *
   7  * This file contains driver APIs to the irq subsystem.
   8  */
   9
  10 #define pr_fmt(fmt) "genirq: " fmt
  11
  12 #include <linux/irq.h>
  13 #include <linux/kthread.h>
  14 #include <linux/module.h>
  15 #include <linux/random.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/slab.h>
  18 #include <linux/sched.h>
  19 #include <linux/sched/rt.h>
  20 #include <linux/task_work.h>
  21
  22 #include "internals.h"
  23
  24 #ifdef CONFIG_IRQ_FORCED_THREADING
  25 __read_mostly bool force_irqthreads;
  26
  27 static int __init setup_forced_irqthreads(char *arg)
  28 {
  29         force_irqthreads = true;
  30         return 0;
  31 }
  32 early_param("threadirqs", setup_forced_irqthreads);
  33 #endif
  34
  35 static void __synchronize_hardirq(struct irq_desc *desc)
  36 {
  37         bool inprogress;
  38
  39         do {
  40                 unsigned long flags;
  41
  42                 /*
  43                  * Wait until we're out of the critical section.  This might
  44                  * give the wrong answer due to the lack of memory barriers.
  45                  */
  46                 while (irqd_irq_inprogress(&desc->irq_data))
  47                         cpu_relax();
  48
  49                 /* Ok, that indicated we're done: double-check carefully. */
  50                 raw_spin_lock_irqsave(&desc->lock, flags);
  51                 inprogress = irqd_irq_inprogress(&desc->irq_data);
  52                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  53
  54                 /* Oops, that failed? */
  55         } while (inprogress);
  56 }
  57
  58 /**
  59  *      synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
  60  *      @irq: interrupt number to wait for
  61  *
  62  *      This function waits for any pending hard IRQ handlers for this
  63  *      interrupt to complete before returning. If you use this
  64  *      function while holding a resource the IRQ handler may need you
  65  *      will deadlock. It does not take associated threaded handlers
  66  *      into account.
  67  *
  68  *      Do not use this for shutdown scenarios where you must be sure
  69  *      that all parts (hardirq and threaded handler) have completed.
  70  *
  71  *      This function may be called - with care - from IRQ context.
  72  */
  73 void synchronize_hardirq(unsigned int irq)
  74 {
  75         struct irq_desc *desc = irq_to_desc(irq);
  76
  77         if (desc)
  78                 __synchronize_hardirq(desc);
  79 }
  80 EXPORT_SYMBOL(synchronize_hardirq);
  81
  82 /**
  83  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
  84  *      @irq: interrupt number to wait for
  85  *
  86  *      This function waits for any pending IRQ handlers for this interrupt
  87  *      to complete before returning. If you use this function while
  88  *      holding a resource the IRQ handler may need you will deadlock.
  89  *
  90  *      This function may be called - with care - from IRQ context.
  91  */
  92 void synchronize_irq(unsigned int irq)
  93 {
  94         struct irq_desc *desc = irq_to_desc(irq);
  95
  96         if (desc) {
  97                 __synchronize_hardirq(desc);
  98                 /*
  99                  * We made sure that no hardirq handler is
 100                  * running. Now verify that no threaded handlers are
 101                  * active.
 102                  */
 103                 wait_event(desc->wait_for_threads,
 104                            !atomic_read(&desc->threads_active));
 105         }
 106 }
 107 EXPORT_SYMBOL(synchronize_irq);
 108
 109 #ifdef CONFIG_SMP
 110 cpumask_var_t irq_default_affinity;
 111
 112 /**
 113  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
 114  *      @irq:           Interrupt to check
 115  *
 116  */
 117 int irq_can_set_affinity(unsigned int irq)
 118 {
 119         struct irq_desc *desc = irq_to_desc(irq);
 120
 121         if (!desc || !irqd_can_balance(&desc->irq_data) ||
 122             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
 123                 return 0;
 124
 125         return 1;
 126 }
 127
 128 /**
 129  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
 130  *      @desc:          irq descriptor which has affitnity changed
 131  *
 132  *      We just set IRQTF_AFFINITY and delegate the affinity setting
 133  *      to the interrupt thread itself. We can not call
 134  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
 135  *      code can be called from hard interrupt context.
 136  */
 137 void irq_set_thread_affinity(struct irq_desc *desc)
 138 {
 139         struct irqaction *action = desc->action;
 140
 141         while (action) {
 142                 if (action->thread)
 143                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
 144                 action = action->next;
 145         }
 146 }
 147
 148 #ifdef CONFIG_GENERIC_PENDING_IRQ
 149 static inline bool irq_can_move_pcntxt(struct irq_data *data)
 150 {
 151         return irqd_can_move_in_process_context(data);
 152 }
 153 static inline bool irq_move_pending(struct irq_data *data)
 154 {
 155         return irqd_is_setaffinity_pending(data);
 156 }
 157 static inline void
 158 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
 159 {
 160         cpumask_copy(desc->pending_mask, mask);
 161 }
 162 static inline void
 163 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
 164 {
 165         cpumask_copy(mask, desc->pending_mask);
 166 }
 167 #else
 168 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
 169 static inline bool irq_move_pending(struct irq_data *data) { return false; }
 170 static inline void
 171 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
 172 static inline void
 173 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
 174 #endif
 175
 176 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 177                         bool force)
 178 {
 179         struct irq_desc *desc = irq_data_to_desc(data);
 180         struct irq_chip *chip = irq_data_get_irq_chip(data);
 181         int ret;
 182
 183         ret = chip->irq_set_affinity(data, mask, force);
 184         switch (ret) {
 185         case IRQ_SET_MASK_OK:
 186                 cpumask_copy(data->affinity, mask);
 187         case IRQ_SET_MASK_OK_NOCOPY:
 188                 irq_set_thread_affinity(desc);
 189                 ret = 0;
 190         }
 191
 192         return ret;
 193 }
 194
 195 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
 196                             bool force)
 197 {
 198         struct irq_chip *chip = irq_data_get_irq_chip(data);
 199         struct irq_desc *desc = irq_data_to_desc(data);
 200         int ret = 0;
 201
 202         if (!chip || !chip->irq_set_affinity)
 203                 return -EINVAL;
 204
 205         if (irq_can_move_pcntxt(data)) {
 206                 ret = irq_do_set_affinity(data, mask, force);
 207         } else {
 208                 irqd_set_move_pending(data);
 209                 irq_copy_pending(desc, mask);
 210         }
 211
 212         if (desc->affinity_notify) {
 213                 kref_get(&desc->affinity_notify->kref);
 214                 schedule_work(&desc->affinity_notify->work);
 215         }
 216         irqd_set(data, IRQD_AFFINITY_SET);
 217
 218         return ret;
 219 }
 220
 221 int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
 222 {
 223         struct irq_desc *desc = irq_to_desc(irq);
 224         unsigned long flags;
 225         int ret;
 226
 227         if (!desc)
 228                 return -EINVAL;
 229
 230         raw_spin_lock_irqsave(&desc->lock, flags);
 231         ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
 232         raw_spin_unlock_irqrestore(&desc->lock, flags);
 233         return ret;
 234 }
 235
 236 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 237 {
 238         unsigned long flags;
 239         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 240
 241         if (!desc)
 242                 return -EINVAL;
 243         desc->affinity_hint = m;
 244         irq_put_desc_unlock(desc, flags);
 245         return 0;
 246 }
 247 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
 248
 249 static void irq_affinity_notify(struct work_struct *work)
 250 {
 251         struct irq_affinity_notify *notify =
 252                 container_of(work, struct irq_affinity_notify, work);
 253         struct irq_desc *desc = irq_to_desc(notify->irq);
 254         cpumask_var_t cpumask;
 255         unsigned long flags;
 256
 257         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
 258                 goto out;
 259
 260         raw_spin_lock_irqsave(&desc->lock, flags);
 261         if (irq_move_pending(&desc->irq_data))
 262                 irq_get_pending(cpumask, desc);
 263         else
 264                 cpumask_copy(cpumask, desc->irq_data.affinity);
 265         raw_spin_unlock_irqrestore(&desc->lock, flags);
 266
 267         notify->notify(notify, cpumask);
 268
 269         free_cpumask_var(cpumask);
 270 out:
 271         kref_put(&notify->kref, notify->release);
 272 }
 273
 274 /**
 275  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
 276  *      @irq:           Interrupt for which to enable/disable notification
 277  *      @notify:        Context for notification, or %NULL to disable
 278  *                      notification.  Function pointers must be initialised;
 279  *                      the other fields will be initialised by this function.
 280  *
 281  *      Must be called in process context.  Notification may only be enabled
 282  *      after the IRQ is allocated and must be disabled before the IRQ is
 283  *      freed using free_irq().
 284  */
 285 int
 286 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 287 {
 288         struct irq_desc *desc = irq_to_desc(irq);
 289         struct irq_affinity_notify *old_notify;
 290         unsigned long flags;
 291
 292         /* The release function is promised process context */
 293         might_sleep();
 294
 295         if (!desc)
 296                 return -EINVAL;
 297
 298         /* Complete initialisation of *notify */
 299         if (notify) {
 300                 notify->irq = irq;
 301                 kref_init(&notify->kref);
 302                 INIT_WORK(&notify->work, irq_affinity_notify);
 303         }
 304
 305         raw_spin_lock_irqsave(&desc->lock, flags);
 306         old_notify = desc->affinity_notify;
 307         desc->affinity_notify = notify;
 308         raw_spin_unlock_irqrestore(&desc->lock, flags);
 309
 310         if (old_notify)
 311                 kref_put(&old_notify->kref, old_notify->release);
 312
 313         return 0;
 314 }
 315 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
 316
 317 #ifndef CONFIG_AUTO_IRQ_AFFINITY
 318 /*
 319  * Generic version of the affinity autoselector.
 320  */
 321 static int
 322 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 323 {
 324         struct cpumask *set = irq_default_affinity;
 325         int node = desc->irq_data.node;
 326
 327         /* Excludes PER_CPU and NO_BALANCE interrupts */
 328         if (!irq_can_set_affinity(irq))
 329                 return 0;
 330
 331         /*
 332          * Preserve an userspace affinity setup, but make sure that
 333          * one of the targets is online.
 334          */
 335         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
 336                 if (cpumask_intersects(desc->irq_data.affinity,
 337                                        cpu_online_mask))
 338                         set = desc->irq_data.affinity;
 339                 else
 340                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 341         }
 342
 343         cpumask_and(mask, cpu_online_mask, set);
 344         if (node != NUMA_NO_NODE) {
 345                 const struct cpumask *nodemask = cpumask_of_node(node);
 346
 347                 /* make sure at least one of the cpus in nodemask is online */
 348                 if (cpumask_intersects(mask, nodemask))
 349                         cpumask_and(mask, mask, nodemask);
 350         }
 351         irq_do_set_affinity(&desc->irq_data, mask, false);
 352         return 0;
 353 }
 354 #else
 355 static inline int
 356 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
 357 {
 358         return irq_select_affinity(irq);
 359 }
 360 #endif
 361
 362 /*
 363  * Called when affinity is set via /proc/irq
 364  */
 365 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
 366 {
 367         struct irq_desc *desc = irq_to_desc(irq);
 368         unsigned long flags;
 369         int ret;
 370
 371         raw_spin_lock_irqsave(&desc->lock, flags);
 372         ret = setup_affinity(irq, desc, mask);
 373         raw_spin_unlock_irqrestore(&desc->lock, flags);
 374         return ret;
 375 }
 376
 377 #else
 378 static inline int
 379 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 380 {
 381         return 0;
 382 }
 383 #endif
 384
 385 void __disable_irq(struct irq_desc *desc, unsigned int irq)
 386 {
 387         if (!desc->depth++)
 388                 irq_disable(desc);
 389 }
 390
 391 static int __disable_irq_nosync(unsigned int irq)
 392 {
 393         unsigned long flags;
 394         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 395
 396         if (!desc)
 397                 return -EINVAL;
 398         __disable_irq(desc, irq);
 399         irq_put_desc_busunlock(desc, flags);
 400         return 0;
 401 }
 402
 403 /**
 404  *      disable_irq_nosync - disable an irq without waiting
 405  *      @irq: Interrupt to disable
 406  *
 407  *      Disable the selected interrupt line.  Disables and Enables are
 408  *      nested.
 409  *      Unlike disable_irq(), this function does not ensure existing
 410  *      instances of the IRQ handler have completed before returning.
 411  *
 412  *      This function may be called from IRQ context.
 413  */
 414 void disable_irq_nosync(unsigned int irq)
 415 {
 416         __disable_irq_nosync(irq);
 417 }
 418 EXPORT_SYMBOL(disable_irq_nosync);
 419
 420 /**
 421  *      disable_irq - disable an irq and wait for completion
 422  *      @irq: Interrupt to disable
 423  *
 424  *      Disable the selected interrupt line.  Enables and Disables are
 425  *      nested.
 426  *      This function waits for any pending IRQ handlers for this interrupt
 427  *      to complete before returning. If you use this function while
 428  *      holding a resource the IRQ handler may need you will deadlock.
 429  *
 430  *      This function may be called - with care - from IRQ context.
 431  */
 432 void disable_irq(unsigned int irq)
 433 {
 434         if (!__disable_irq_nosync(irq))
 435                 synchronize_irq(irq);
 436 }
 437 EXPORT_SYMBOL(disable_irq);
 438
 439 void __enable_irq(struct irq_desc *desc, unsigned int irq)
 440 {
 441         switch (desc->depth) {
 442         case 0:
 443  err_out:
 444                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
 445                 break;
 446         case 1: {
 447                 if (desc->istate & IRQS_SUSPENDED)
 448                         goto err_out;
 449                 /* Prevent probing on this irq: */
 450                 irq_settings_set_noprobe(desc);
 451                 irq_enable(desc);
 452                 check_irq_resend(desc, irq);
 453                 /* fall-through */
 454         }
 455         default:
 456                 desc->depth--;
 457         }
 458 }
 459
 460 /**
 461  *      enable_irq - enable handling of an irq
 462  *      @irq: Interrupt to enable
 463  *
 464  *      Undoes the effect of one call to disable_irq().  If this
 465  *      matches the last disable, processing of interrupts on this
 466  *      IRQ line is re-enabled.
 467  *
 468  *      This function may be called from IRQ context only when
 469  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
 470  */
 471 void enable_irq(unsigned int irq)
 472 {
 473         unsigned long flags;
 474         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 475
 476         if (!desc)
 477                 return;
 478         if (WARN(!desc->irq_data.chip,
 479                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
 480                 goto out;
 481
 482         __enable_irq(desc, irq);
 483 out:
 484         irq_put_desc_busunlock(desc, flags);
 485 }
 486 EXPORT_SYMBOL(enable_irq);
 487
 488 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 489 {
 490         struct irq_desc *desc = irq_to_desc(irq);
 491         int ret = -ENXIO;
 492
 493         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 494                 return 0;
 495
 496         if (desc->irq_data.chip->irq_set_wake)
 497                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
 498
 499         return ret;
 500 }
 501
 502 /**
 503  *      irq_set_irq_wake - control irq power management wakeup
 504  *      @irq:   interrupt to control
 505  *      @on:    enable/disable power management wakeup
 506  *
 507  *      Enable/disable power management wakeup mode, which is
 508  *      disabled by default.  Enables and disables must match,
 509  *      just as they match for non-wakeup mode support.
 510  *
 511  *      Wakeup mode lets this IRQ wake the system from sleep
 512  *      states like "suspend to RAM".
 513  */
 514 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 515 {
 516         unsigned long flags;
 517         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 518         int ret = 0;
 519
 520         if (!desc)
 521                 return -EINVAL;
 522
 523         /* wakeup-capable irqs can be shared between drivers that
 524          * don't need to have the same sleep mode behaviors.
 525          */
 526         if (on) {
 527                 if (desc->wake_depth++ == 0) {
 528                         ret = set_irq_wake_real(irq, on);
 529                         if (ret)
 530                                 desc->wake_depth = 0;
 531                         else
 532                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 533                 }
 534         } else {
 535                 if (desc->wake_depth == 0) {
 536                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 537                 } else if (--desc->wake_depth == 0) {
 538                         ret = set_irq_wake_real(irq, on);
 539                         if (ret)
 540                                 desc->wake_depth = 1;
 541                         else
 542                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 543                 }
 544         }
 545         irq_put_desc_busunlock(desc, flags);
 546         return ret;
 547 }
 548 EXPORT_SYMBOL(irq_set_irq_wake);
 549
 550 /*
 551  * Internal function that tells the architecture code whether a
 552  * particular irq has been exclusively allocated or is available
 553  * for driver use.
 554  */
 555 int can_request_irq(unsigned int irq, unsigned long irqflags)
 556 {
 557         unsigned long flags;
 558         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 559         int canrequest = 0;
 560
 561         if (!desc)
 562                 return 0;
 563
 564         if (irq_settings_can_request(desc)) {
 565                 if (!desc->action ||
 566                     irqflags & desc->action->flags & IRQF_SHARED)
 567                         canrequest = 1;
 568         }
 569         irq_put_desc_unlock(desc, flags);
 570         return canrequest;
 571 }
 572
 573 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 574                       unsigned long flags)
 575 {
 576         struct irq_chip *chip = desc->irq_data.chip;
 577         int ret, unmask = 0;
 578
 579         if (!chip || !chip->irq_set_type) {
 580                 /*
 581                  * IRQF_TRIGGER_* but the PIC does not support multiple
 582                  * flow-types?
 583                  */
 584                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
 585                          chip ? (chip->name ? : "unknown") : "unknown");
 586                 return 0;
 587         }
 588
 589         flags &= IRQ_TYPE_SENSE_MASK;
 590
 591         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 592                 if (!irqd_irq_masked(&desc->irq_data))
 593                         mask_irq(desc);
 594                 if (!irqd_irq_disabled(&desc->irq_data))
 595                         unmask = 1;
 596         }
 597
 598         /* caller masked out all except trigger mode flags */
 599         ret = chip->irq_set_type(&desc->irq_data, flags);
 600
 601         switch (ret) {
 602         case IRQ_SET_MASK_OK:
 603                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 604                 irqd_set(&desc->irq_data, flags);
 605
 606         case IRQ_SET_MASK_OK_NOCOPY:
 607                 flags = irqd_get_trigger_type(&desc->irq_data);
 608                 irq_settings_set_trigger_mask(desc, flags);
 609                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
 610                 irq_settings_clr_level(desc);
 611                 if (flags & IRQ_TYPE_LEVEL_MASK) {
 612                         irq_settings_set_level(desc);
 613                         irqd_set(&desc->irq_data, IRQD_LEVEL);
 614                 }
 615
 616                 ret = 0;
 617                 break;
 618         default:
 619                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
 620                        flags, irq, chip->irq_set_type);
 621         }
 622         if (unmask)
 623                 unmask_irq(desc);
 624         return ret;
 625 }
 626
 627 #ifdef CONFIG_HARDIRQS_SW_RESEND
 628 int irq_set_parent(int irq, int parent_irq)
 629 {
 630         unsigned long flags;
 631         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 632
 633         if (!desc)
 634                 return -EINVAL;
 635
 636         desc->parent_irq = parent_irq;
 637
 638         irq_put_desc_unlock(desc, flags);
 639         return 0;
 640 }
 641 #endif
 642
 643 /*
 644  * Default primary interrupt handler for threaded interrupts. Is
 645  * assigned as primary handler when request_threaded_irq is called
 646  * with handler == NULL. Useful for oneshot interrupts.
 647  */
 648 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 649 {
 650         return IRQ_WAKE_THREAD;
 651 }
 652
 653 /*
 654  * Primary handler for nested threaded interrupts. Should never be
 655  * called.
 656  */
 657 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 658 {
 659         WARN(1, "Primary handler called for nested irq %d\n", irq);
 660         return IRQ_NONE;
 661 }
 662
 663 static int irq_wait_for_interrupt(struct irqaction *action)
 664 {
 665         set_current_state(TASK_INTERRUPTIBLE);
 666
 667         while (!kthread_should_stop()) {
 668
 669                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
 670                                        &action->thread_flags)) {
 671                         __set_current_state(TASK_RUNNING);
 672                         return 0;
 673                 }
 674                 schedule();
 675                 set_current_state(TASK_INTERRUPTIBLE);
 676         }
 677         __set_current_state(TASK_RUNNING);
 678         return -1;
 679 }
 680
 681 /*
 682  * Oneshot interrupts keep the irq line masked until the threaded
 683  * handler finished. unmask if the interrupt has not been disabled and
 684  * is marked MASKED.
 685  */
 686 static void irq_finalize_oneshot(struct irq_desc *desc,
 687                                  struct irqaction *action)
 688 {
 689         if (!(desc->istate & IRQS_ONESHOT))
 690                 return;
 691 again:
 692         chip_bus_lock(desc);
 693         raw_spin_lock_irq(&desc->lock);
 694
 695         /*
 696          * Implausible though it may be we need to protect us against
 697          * the following scenario:
 698          *
 699          * The thread is faster done than the hard interrupt handler
 700          * on the other CPU. If we unmask the irq line then the
 701          * interrupt can come in again and masks the line, leaves due
 702          * to IRQS_INPROGRESS and the irq line is masked forever.
 703          *
 704          * This also serializes the state of shared oneshot handlers
 705          * versus "desc->threads_onehsot |= action->thread_mask;" in
 706          * irq_wake_thread(). See the comment there which explains the
 707          * serialization.
 708          */
 709         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 710                 raw_spin_unlock_irq(&desc->lock);
 711                 chip_bus_sync_unlock(desc);
 712                 cpu_relax();
 713                 goto again;
 714         }
 715
 716         /*
 717          * Now check again, whether the thread should run. Otherwise
 718          * we would clear the threads_oneshot bit of this thread which
 719          * was just set.
 720          */
 721         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 722                 goto out_unlock;
 723
 724         desc->threads_oneshot &= ~action->thread_mask;
 725
 726         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 727             irqd_irq_masked(&desc->irq_data))
 728                 unmask_threaded_irq(desc);
 729
 730 out_unlock:
 731         raw_spin_unlock_irq(&desc->lock);
 732         chip_bus_sync_unlock(desc);
 733 }
 734
 735 #ifdef CONFIG_SMP
 736 /*
 737  * Check whether we need to change the affinity of the interrupt thread.
 738  */
 739 static void
 740 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 741 {
 742         cpumask_var_t mask;
 743         bool valid = true;
 744
 745         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 746                 return;
 747
 748         /*
 749          * In case we are out of memory we set IRQTF_AFFINITY again and
 750          * try again next time
 751          */
 752         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 753                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
 754                 return;
 755         }
 756
 757         raw_spin_lock_irq(&desc->lock);
 758         /*
 759          * This code is triggered unconditionally. Check the affinity
 760          * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
 761          */
 762         if (desc->irq_data.affinity)
 763                 cpumask_copy(mask, desc->irq_data.affinity);
 764         else
 765                 valid = false;
 766         raw_spin_unlock_irq(&desc->lock);
 767
 768         if (valid)
 769                 set_cpus_allowed_ptr(current, mask);
 770         free_cpumask_var(mask);
 771 }
 772 #else
 773 static inline void
 774 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 775 #endif
 776
 777 /*
 778  * Interrupts which are not explicitely requested as threaded
 779  * interrupts rely on the implicit bh/preempt disable of the hard irq
 780  * context. So we need to disable bh here to avoid deadlocks and other
 781  * side effects.
 782  */
 783 static irqreturn_t
 784 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 785 {
 786         irqreturn_t ret;
 787
 788         local_bh_disable();
 789         ret = action->thread_fn(action->irq, action->dev_id);
 790         irq_finalize_oneshot(desc, action);
 791         local_bh_enable();
 792         return ret;
 793 }
 794
 795 /*
 796  * Interrupts explicitly requested as threaded interrupts want to be
 797  * preemtible - many of them need to sleep and wait for slow busses to
 798  * complete.
 799  */
 800 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 801                 struct irqaction *action)
 802 {
 803         irqreturn_t ret;
 804
 805         ret = action->thread_fn(action->irq, action->dev_id);
 806         irq_finalize_oneshot(desc, action);
 807         return ret;
 808 }
 809
 810 static void wake_threads_waitq(struct irq_desc *desc)
 811 {
 812         if (atomic_dec_and_test(&desc->threads_active))
 813                 wake_up(&desc->wait_for_threads);
 814 }
 815
 816 static void irq_thread_dtor(struct callback_head *unused)
 817 {
 818         struct task_struct *tsk = current;
 819         struct irq_desc *desc;
 820         struct irqaction *action;
 821
 822         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
 823                 return;
 824
 825         action = kthread_data(tsk);
 826
 827         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 828                tsk->comm, tsk->pid, action->irq);
 829
 830
 831         desc = irq_to_desc(action->irq);
 832         /*
 833          * If IRQTF_RUNTHREAD is set, we need to decrement
 834          * desc->threads_active and wake possible waiters.
 835          */
 836         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 837                 wake_threads_waitq(desc);
 838
 839         /* Prevent a stale desc->threads_oneshot */
 840         irq_finalize_oneshot(desc, action);
 841 }
 842
 843 /*
 844  * Interrupt handler thread
 845  */
 846 static int irq_thread(void *data)
 847 {
 848         struct callback_head on_exit_work;
 849         struct irqaction *action = data;
 850         struct irq_desc *desc = irq_to_desc(action->irq);
 851         irqreturn_t (*handler_fn)(struct irq_desc *desc,
 852                         struct irqaction *action);
 853
 854         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 855                                         &action->thread_flags))
 856                 handler_fn = irq_forced_thread_fn;
 857         else
 858                 handler_fn = irq_thread_fn;
 859
 860         init_task_work(&on_exit_work, irq_thread_dtor);
 861         task_work_add(current, &on_exit_work, false);
 862
 863         irq_thread_check_affinity(desc, action);
 864
 865         while (!irq_wait_for_interrupt(action)) {
 866                 irqreturn_t action_ret;
 867
 868                 irq_thread_check_affinity(desc, action);
 869
 870                 action_ret = handler_fn(desc, action);
 871                 if (action_ret == IRQ_HANDLED)
 872                         atomic_inc(&desc->threads_handled);
 873
 874                 wake_threads_waitq(desc);
 875         }
 876
 877         /*
 878          * This is the regular exit path. __free_irq() is stopping the
 879          * thread via kthread_stop() after calling
 880          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
 881          * oneshot mask bit can be set. We cannot verify that as we
 882          * cannot touch the oneshot mask at this point anymore as
 883          * __setup_irq() might have given out currents thread_mask
 884          * again.
 885          */
 886         task_work_cancel(current, irq_thread_dtor);
 887         return 0;
 888 }
 889
 890 /**
 891  *      irq_wake_thread - wake the irq thread for the action identified by dev_id
 892  *      @irq:           Interrupt line
 893  *      @dev_id:        Device identity for which the thread should be woken
 894  *
 895  */
 896 void irq_wake_thread(unsigned int irq, void *dev_id)
 897 {
 898         struct irq_desc *desc = irq_to_desc(irq);
 899         struct irqaction *action;
 900         unsigned long flags;
 901
 902         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
 903                 return;
 904
 905         raw_spin_lock_irqsave(&desc->lock, flags);
 906         for (action = desc->action; action; action = action->next) {
 907                 if (action->dev_id == dev_id) {
 908                         if (action->thread)
 909                                 __irq_wake_thread(desc, action);
 910                         break;
 911                 }
 912         }
 913         raw_spin_unlock_irqrestore(&desc->lock, flags);
 914 }
 915 EXPORT_SYMBOL_GPL(irq_wake_thread);
 916
 917 static void irq_setup_forced_threading(struct irqaction *new)
 918 {
 919         if (!force_irqthreads)
 920                 return;
 921         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 922                 return;
 923
 924         new->flags |= IRQF_ONESHOT;
 925
 926         if (!new->thread_fn) {
 927                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 928                 new->thread_fn = new->handler;
 929                 new->handler = irq_default_primary_handler;
 930         }
 931 }
 932
 933 static int irq_request_resources(struct irq_desc *desc)
 934 {
 935         struct irq_data *d = &desc->irq_data;
 936         struct irq_chip *c = d->chip;
 937
 938         return c->irq_request_resources ? c->irq_request_resources(d) : 0;
 939 }
 940
 941 static void irq_release_resources(struct irq_desc *desc)
 942 {
 943         struct irq_data *d = &desc->irq_data;
 944         struct irq_chip *c = d->chip;
 945
 946         if (c->irq_release_resources)
 947                 c->irq_release_resources(d);
 948 }
 949
 950 /*
 951  * Internal function to register an irqaction - typically used to
 952  * allocate special interrupts that are part of the architecture.
 953  */
 954 static int
 955 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 956 {
 957         struct irqaction *old, **old_ptr;
 958         unsigned long flags, thread_mask = 0;
 959         int ret, nested, shared = 0;
 960         cpumask_var_t mask;
 961
 962         if (!desc)
 963                 return -EINVAL;
 964
 965         if (desc->irq_data.chip == &no_irq_chip)
 966                 return -ENOSYS;
 967         if (!try_module_get(desc->owner))
 968                 return -ENODEV;
 969
 970         /*
 971          * Check whether the interrupt nests into another interrupt
 972          * thread.
 973          */
 974         nested = irq_settings_is_nested_thread(desc);
 975         if (nested) {
 976                 if (!new->thread_fn) {
 977                         ret = -EINVAL;
 978                         goto out_mput;
 979                 }
 980                 /*
 981                  * Replace the primary handler which was provided from
 982                  * the driver for non nested interrupt handling by the
 983                  * dummy function which warns when called.
 984                  */
 985                 new->handler = irq_nested_primary_handler;
 986         } else {
 987                 if (irq_settings_can_thread(desc))
 988                         irq_setup_forced_threading(new);
 989         }
 990
 991         /*
 992          * Create a handler thread when a thread function is supplied
 993          * and the interrupt does not nest into another interrupt
 994          * thread.
 995          */
 996         if (new->thread_fn && !nested) {
 997                 struct task_struct *t;
 998                 static const struct sched_param param = {
 999                         .sched_priority = MAX_USER_RT_PRIO/2,
1000                 };
1001
1002                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1003                                    new->name);
1004                 if (IS_ERR(t)) {
1005                         ret = PTR_ERR(t);
1006                         goto out_mput;
1007                 }
1008
1009                 sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
1010
1011                 /*
1012                  * We keep the reference to the task struct even if
1013                  * the thread dies to avoid that the interrupt code
1014                  * references an already freed task_struct.
1015                  */
1016                 get_task_struct(t);
1017                 new->thread = t;
1018                 /*
1019                  * Tell the thread to set its affinity. This is
1020                  * important for shared interrupt handlers as we do
1021                  * not invoke setup_affinity() for the secondary
1022                  * handlers as everything is already set up. Even for
1023                  * interrupts marked with IRQF_NO_BALANCE this is
1024                  * correct as we want the thread to move to the cpu(s)
1025                  * on which the requesting code placed the interrupt.
1026                  */
1027                 set_bit(IRQTF_AFFINITY, &new->thread_flags);
1028         }
1029
1030         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1031                 ret = -ENOMEM;
1032                 goto out_thread;
1033         }
1034
1035         /*
1036          * Drivers are often written to work w/o knowledge about the
1037          * underlying irq chip implementation, so a request for a
1038          * threaded irq without a primary hard irq context handler
1039          * requires the ONESHOT flag to be set. Some irq chips like
1040          * MSI based interrupts are per se one shot safe. Check the
1041          * chip flags, so we can avoid the unmask dance at the end of
1042          * the threaded handler for those.
1043          */
1044         if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1045                 new->flags &= ~IRQF_ONESHOT;
1046
1047         /*
1048          * The following block of code has to be executed atomically
1049          */
1050         raw_spin_lock_irqsave(&desc->lock, flags);
1051         old_ptr = &desc->action;
1052         old = *old_ptr;
1053         if (old) {
1054                 /*
1055                  * Can't share interrupts unless both agree to and are
1056                  * the same type (level, edge, polarity). So both flag
1057                  * fields must have IRQF_SHARED set and the bits which
1058                  * set the trigger type must match. Also all must
1059                  * agree on ONESHOT.
1060                  */
1061                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1062                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1063                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
1064                         goto mismatch;
1065
1066                 /* All handlers must agree on per-cpuness */
1067                 if ((old->flags & IRQF_PERCPU) !=
1068                     (new->flags & IRQF_PERCPU))
1069                         goto mismatch;
1070
1071                 /* add new interrupt at end of irq queue */
1072                 do {
1073                         /*
1074                          * Or all existing action->thread_mask bits,
1075                          * so we can find the next zero bit for this
1076                          * new action.
1077                          */
1078                         thread_mask |= old->thread_mask;
1079                         old_ptr = &old->next;
1080                         old = *old_ptr;
1081                 } while (old);
1082                 shared = 1;
1083         }
1084
1085         /*
1086          * Setup the thread mask for this irqaction for ONESHOT. For
1087          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1088          * conditional in irq_wake_thread().
1089          */
1090         if (new->flags & IRQF_ONESHOT) {
1091                 /*
1092                  * Unlikely to have 32 resp 64 irqs sharing one line,
1093                  * but who knows.
1094                  */
1095                 if (thread_mask == ~0UL) {
1096                         ret = -EBUSY;
1097                         goto out_mask;
1098                 }
1099                 /*
1100                  * The thread_mask for the action is or'ed to
1101                  * desc->thread_active to indicate that the
1102                  * IRQF_ONESHOT thread handler has been woken, but not
1103                  * yet finished. The bit is cleared when a thread
1104                  * completes. When all threads of a shared interrupt
1105                  * line have completed desc->threads_active becomes
1106                  * zero and the interrupt line is unmasked. See
1107                  * handle.c:irq_wake_thread() for further information.
1108                  *
1109                  * If no thread is woken by primary (hard irq context)
1110                  * interrupt handlers, then desc->threads_active is
1111                  * also checked for zero to unmask the irq line in the
1112                  * affected hard irq flow handlers
1113                  * (handle_[fasteoi|level]_irq).
1114                  *
1115                  * The new action gets the first zero bit of
1116                  * thread_mask assigned. See the loop above which or's
1117                  * all existing action->thread_mask bits.
1118                  */
1119                 new->thread_mask = 1 << ffz(thread_mask);
1120
1121         } else if (new->handler == irq_default_primary_handler &&
1122                    !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1123                 /*
1124                  * The interrupt was requested with handler = NULL, so
1125                  * we use the default primary handler for it. But it
1126                  * does not have the oneshot flag set. In combination
1127                  * with level interrupts this is deadly, because the
1128                  * default primary handler just wakes the thread, then
1129                  * the irq lines is reenabled, but the device still
1130                  * has the level irq asserted. Rinse and repeat....
1131                  *
1132                  * While this works for edge type interrupts, we play
1133                  * it safe and reject unconditionally because we can't
1134                  * say for sure which type this interrupt really
1135                  * has. The type flags are unreliable as the
1136                  * underlying chip implementation can override them.
1137                  */
1138                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1139                        irq);
1140                 ret = -EINVAL;
1141                 goto out_mask;
1142         }
1143
1144         if (!shared) {
1145                 ret = irq_request_resources(desc);
1146                 if (ret) {
1147                         pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1148                                new->name, irq, desc->irq_data.chip->name);
1149                         goto out_mask;
1150                 }
1151
1152                 init_waitqueue_head(&desc->wait_for_threads);
1153
1154                 /* Setup the type (level, edge polarity) if configured: */
1155                 if (new->flags & IRQF_TRIGGER_MASK) {
1156                         ret = __irq_set_trigger(desc, irq,
1157                                         new->flags & IRQF_TRIGGER_MASK);
1158
1159                         if (ret)
1160                                 goto out_mask;
1161                 }
1162
1163                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1164                                   IRQS_ONESHOT | IRQS_WAITING);
1165                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1166
1167                 if (new->flags & IRQF_PERCPU) {
1168                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1169                         irq_settings_set_per_cpu(desc);
1170                 }
1171
1172                 if (new->flags & IRQF_ONESHOT)
1173                         desc->istate |= IRQS_ONESHOT;
1174
1175                 if (irq_settings_can_autoenable(desc))
1176                         irq_startup(desc, true);
1177                 else
1178                         /* Undo nested disables: */
1179                         desc->depth = 1;
1180
1181                 /* Exclude IRQ from balancing if requested */
1182                 if (new->flags & IRQF_NOBALANCING) {
1183                         irq_settings_set_no_balancing(desc);
1184                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1185                 }
1186
1187                 /* Set default affinity mask once everything is setup */
1188                 setup_affinity(irq, desc, mask);
1189
1190         } else if (new->flags & IRQF_TRIGGER_MASK) {
1191                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1192                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1193
1194                 if (nmsk != omsk)
1195                         /* hope the handler works with current  trigger mode */
1196                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1197                                    irq, nmsk, omsk);
1198         }
1199
1200         new->irq = irq;
1201         *old_ptr = new;
1202
1203         irq_pm_install_action(desc, new);
1204
1205         /* Reset broken irq detection when installing new handler */
1206         desc->irq_count = 0;
1207         desc->irqs_unhandled = 0;
1208
1209         /*
1210          * Check whether we disabled the irq via the spurious handler
1211          * before. Reenable it and give it another chance.
1212          */
1213         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1214                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1215                 __enable_irq(desc, irq);
1216         }
1217
1218         raw_spin_unlock_irqrestore(&desc->lock, flags);
1219
1220         /*
1221          * Strictly no need to wake it up, but hung_task complains
1222          * when no hard interrupt wakes the thread up.
1223          */
1224         if (new->thread)
1225                 wake_up_process(new->thread);
1226
1227         register_irq_proc(irq, desc);
1228         new->dir = NULL;
1229         register_handler_proc(irq, new);
1230         free_cpumask_var(mask);
1231
1232         return 0;
1233
1234 mismatch:
1235         if (!(new->flags & IRQF_PROBE_SHARED)) {
1236                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1237                        irq, new->flags, new->name, old->flags, old->name);
1238 #ifdef CONFIG_DEBUG_SHIRQ
1239                 dump_stack();
1240 #endif
1241         }
1242         ret = -EBUSY;
1243
1244 out_mask:
1245         raw_spin_unlock_irqrestore(&desc->lock, flags);
1246         free_cpumask_var(mask);
1247
1248 out_thread:
1249         if (new->thread) {
1250                 struct task_struct *t = new->thread;
1251
1252                 new->thread = NULL;
1253                 kthread_stop(t);
1254                 put_task_struct(t);
1255         }
1256 out_mput:
1257         module_put(desc->owner);
1258         return ret;
1259 }
1260
1261 /**
1262  *      setup_irq - setup an interrupt
1263  *      @irq: Interrupt line to setup
1264  *      @act: irqaction for the interrupt
1265  *
1266  * Used to statically setup interrupts in the early boot process.
1267  */
1268 int setup_irq(unsigned int irq, struct irqaction *act)
1269 {
1270         int retval;
1271         struct irq_desc *desc = irq_to_desc(irq);
1272
1273         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1274                 return -EINVAL;
1275         chip_bus_lock(desc);
1276         retval = __setup_irq(irq, desc, act);
1277         chip_bus_sync_unlock(desc);
1278
1279         return retval;
1280 }
1281 EXPORT_SYMBOL_GPL(setup_irq);
1282
1283 /*
1284  * Internal function to unregister an irqaction - used to free
1285  * regular and special interrupts that are part of the architecture.
1286  */
1287 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1288 {
1289         struct irq_desc *desc = irq_to_desc(irq);
1290         struct irqaction *action, **action_ptr;
1291         unsigned long flags;
1292
1293         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1294
1295         if (!desc)
1296                 return NULL;
1297
1298         raw_spin_lock_irqsave(&desc->lock, flags);
1299
1300         /*
1301          * There can be multiple actions per IRQ descriptor, find the right
1302          * one based on the dev_id:
1303          */
1304         action_ptr = &desc->action;
1305         for (;;) {
1306                 action = *action_ptr;
1307
1308                 if (!action) {
1309                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1310                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1311
1312                         return NULL;
1313                 }
1314
1315                 if (action->dev_id == dev_id)
1316                         break;
1317                 action_ptr = &action->next;
1318         }
1319
1320         /* Found it - now remove it from the list of entries: */
1321         *action_ptr = action->next;
1322
1323         irq_pm_remove_action(desc, action);
1324
1325         /* If this was the last handler, shut down the IRQ line: */
1326         if (!desc->action) {
1327                 irq_shutdown(desc);
1328                 irq_release_resources(desc);
1329         }
1330
1331 #ifdef CONFIG_SMP
1332         /* make sure affinity_hint is cleaned up */
1333         if (WARN_ON_ONCE(desc->affinity_hint))
1334                 desc->affinity_hint = NULL;
1335 #endif
1336
1337         raw_spin_unlock_irqrestore(&desc->lock, flags);
1338
1339         unregister_handler_proc(irq, action);
1340
1341         /* Make sure it's not being used on another CPU: */
1342         synchronize_irq(irq);
1343
1344 #ifdef CONFIG_DEBUG_SHIRQ
1345         /*
1346          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1347          * event to happen even now it's being freed, so let's make sure that
1348          * is so by doing an extra call to the handler ....
1349          *
1350          * ( We do this after actually deregistering it, to make sure that a
1351          *   'real' IRQ doesn't run in * parallel with our fake. )
1352          */
1353         if (action->flags & IRQF_SHARED) {
1354                 local_irq_save(flags);
1355                 action->handler(irq, dev_id);
1356                 local_irq_restore(flags);
1357         }
1358 #endif
1359
1360         if (action->thread) {
1361                 kthread_stop(action->thread);
1362                 put_task_struct(action->thread);
1363         }
1364
1365         module_put(desc->owner);
1366         return action;
1367 }
1368
1369 /**
1370  *      remove_irq - free an interrupt
1371  *      @irq: Interrupt line to free
1372  *      @act: irqaction for the interrupt
1373  *
1374  * Used to remove interrupts statically setup by the early boot process.
1375  */
1376 void remove_irq(unsigned int irq, struct irqaction *act)
1377 {
1378         struct irq_desc *desc = irq_to_desc(irq);
1379
1380         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1381             __free_irq(irq, act->dev_id);
1382 }
1383 EXPORT_SYMBOL_GPL(remove_irq);
1384
1385 /**
1386  *      free_irq - free an interrupt allocated with request_irq
1387  *      @irq: Interrupt line to free
1388  *      @dev_id: Device identity to free
1389  *
1390  *      Remove an interrupt handler. The handler is removed and if the
1391  *      interrupt line is no longer in use by any driver it is disabled.
1392  *      On a shared IRQ the caller must ensure the interrupt is disabled
1393  *      on the card it drives before calling this function. The function
1394  *      does not return until any executing interrupts for this IRQ
1395  *      have completed.
1396  *
1397  *      This function must not be called from interrupt context.
1398  */
1399 void free_irq(unsigned int irq, void *dev_id)
1400 {
1401         struct irq_desc *desc = irq_to_desc(irq);
1402
1403         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1404                 return;
1405
1406 #ifdef CONFIG_SMP
1407         if (WARN_ON(desc->affinity_notify))
1408                 desc->affinity_notify = NULL;
1409 #endif
1410
1411         chip_bus_lock(desc);
1412         kfree(__free_irq(irq, dev_id));
1413         chip_bus_sync_unlock(desc);
1414 }
1415 EXPORT_SYMBOL(free_irq);
1416
1417 /**
1418  *      request_threaded_irq - allocate an interrupt line
1419  *      @irq: Interrupt line to allocate
1420  *      @handler: Function to be called when the IRQ occurs.
1421  *                Primary handler for threaded interrupts
1422  *                If NULL and thread_fn != NULL the default
1423  *                primary handler is installed
1424  *      @thread_fn: Function called from the irq handler thread
1425  *                  If NULL, no irq thread is created
1426  *      @irqflags: Interrupt type flags
1427  *      @devname: An ascii name for the claiming device
1428  *      @dev_id: A cookie passed back to the handler function
1429  *
1430  *      This call allocates interrupt resources and enables the
1431  *      interrupt line and IRQ handling. From the point this
1432  *      call is made your handler function may be invoked. Since
1433  *      your handler function must clear any interrupt the board
1434  *      raises, you must take care both to initialise your hardware
1435  *      and to set up the interrupt handler in the right order.
1436  *
1437  *      If you want to set up a threaded irq handler for your device
1438  *      then you need to supply @handler and @thread_fn. @handler is
1439  *      still called in hard interrupt context and has to check
1440  *      whether the interrupt originates from the device. If yes it
1441  *      needs to disable the interrupt on the device and return
1442  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1443  *      @thread_fn. This split handler design is necessary to support
1444  *      shared interrupts.
1445  *
1446  *      Dev_id must be globally unique. Normally the address of the
1447  *      device data structure is used as the cookie. Since the handler
1448  *      receives this value it makes sense to use it.
1449  *
1450  *      If your interrupt is shared you must pass a non NULL dev_id
1451  *      as this is required when freeing the interrupt.
1452  *
1453  *      Flags:
1454  *
1455  *      IRQF_SHARED             Interrupt is shared
1456  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1457  *
1458  */
1459 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1460                          irq_handler_t thread_fn, unsigned long irqflags,
1461                          const char *devname, void *dev_id)
1462 {
1463         struct irqaction *action;
1464         struct irq_desc *desc;
1465         int retval;
1466
1467         /*
1468          * Sanity-check: shared interrupts must pass in a real dev-ID,
1469          * otherwise we'll have trouble later trying to figure out
1470          * which interrupt is which (messes up the interrupt freeing
1471          * logic etc).
1472          */
1473         if ((irqflags & IRQF_SHARED) && !dev_id)
1474                 return -EINVAL;
1475
1476         desc = irq_to_desc(irq);
1477         if (!desc)
1478                 return -EINVAL;
1479
1480         if (!irq_settings_can_request(desc) ||
1481             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1482                 return -EINVAL;
1483
1484         if (!handler) {
1485                 if (!thread_fn)
1486                         return -EINVAL;
1487                 handler = irq_default_primary_handler;
1488         }
1489
1490         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1491         if (!action)
1492                 return -ENOMEM;
1493
1494         action->handler = handler;
1495         action->thread_fn = thread_fn;
1496         action->flags = irqflags;
1497         action->name = devname;
1498         action->dev_id = dev_id;
1499
1500         chip_bus_lock(desc);
1501         retval = __setup_irq(irq, desc, action);
1502         chip_bus_sync_unlock(desc);
1503
1504         if (retval)
1505                 kfree(action);
1506
1507 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1508         if (!retval && (irqflags & IRQF_SHARED)) {
1509                 /*
1510                  * It's a shared IRQ -- the driver ought to be prepared for it
1511                  * to happen immediately, so let's make sure....
1512                  * We disable the irq to make sure that a 'real' IRQ doesn't
1513                  * run in parallel with our fake.
1514                  */
1515                 unsigned long flags;
1516
1517                 disable_irq(irq);
1518                 local_irq_save(flags);
1519
1520                 handler(irq, dev_id);
1521
1522                 local_irq_restore(flags);
1523                 enable_irq(irq);
1524         }
1525 #endif
1526         return retval;
1527 }
1528 EXPORT_SYMBOL(request_threaded_irq);
1529
1530 /**
1531  *      request_any_context_irq - allocate an interrupt line
1532  *      @irq: Interrupt line to allocate
1533  *      @handler: Function to be called when the IRQ occurs.
1534  *                Threaded handler for threaded interrupts.
1535  *      @flags: Interrupt type flags
1536  *      @name: An ascii name for the claiming device
1537  *      @dev_id: A cookie passed back to the handler function
1538  *
1539  *      This call allocates interrupt resources and enables the
1540  *      interrupt line and IRQ handling. It selects either a
1541  *      hardirq or threaded handling method depending on the
1542  *      context.
1543  *
1544  *      On failure, it returns a negative value. On success,
1545  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1546  */
1547 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1548                             unsigned long flags, const char *name, void *dev_id)
1549 {
1550         struct irq_desc *desc = irq_to_desc(irq);
1551         int ret;
1552
1553         if (!desc)
1554                 return -EINVAL;
1555
1556         if (irq_settings_is_nested_thread(desc)) {
1557                 ret = request_threaded_irq(irq, NULL, handler,
1558                                            flags, name, dev_id);
1559                 return !ret ? IRQC_IS_NESTED : ret;
1560         }
1561
1562         ret = request_irq(irq, handler, flags, name, dev_id);
1563         return !ret ? IRQC_IS_HARDIRQ : ret;
1564 }
1565 EXPORT_SYMBOL_GPL(request_any_context_irq);
1566
1567 void enable_percpu_irq(unsigned int irq, unsigned int type)
1568 {
1569         unsigned int cpu = smp_processor_id();
1570         unsigned long flags;
1571         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1572
1573         if (!desc)
1574                 return;
1575
1576         type &= IRQ_TYPE_SENSE_MASK;
1577         if (type != IRQ_TYPE_NONE) {
1578                 int ret;
1579
1580                 ret = __irq_set_trigger(desc, irq, type);
1581
1582                 if (ret) {
1583                         WARN(1, "failed to set type for IRQ%d\n", irq);
1584                         goto out;
1585                 }
1586         }
1587
1588         irq_percpu_enable(desc, cpu);
1589 out:
1590         irq_put_desc_unlock(desc, flags);
1591 }
1592 EXPORT_SYMBOL_GPL(enable_percpu_irq);
1593
1594 void disable_percpu_irq(unsigned int irq)
1595 {
1596         unsigned int cpu = smp_processor_id();
1597         unsigned long flags;
1598         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1599
1600         if (!desc)
1601                 return;
1602
1603         irq_percpu_disable(desc, cpu);
1604         irq_put_desc_unlock(desc, flags);
1605 }
1606 EXPORT_SYMBOL_GPL(disable_percpu_irq);
1607
1608 /*
1609  * Internal function to unregister a percpu irqaction.
1610  */
1611 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1612 {
1613         struct irq_desc *desc = irq_to_desc(irq);
1614         struct irqaction *action;
1615         unsigned long flags;
1616
1617         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1618
1619         if (!desc)
1620                 return NULL;
1621
1622         raw_spin_lock_irqsave(&desc->lock, flags);
1623
1624         action = desc->action;
1625         if (!action || action->percpu_dev_id != dev_id) {
1626                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1627                 goto bad;
1628         }
1629
1630         if (!cpumask_empty(desc->percpu_enabled)) {
1631                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1632                      irq, cpumask_first(desc->percpu_enabled));
1633                 goto bad;
1634         }
1635
1636         /* Found it - now remove it from the list of entries: */
1637         desc->action = NULL;
1638
1639         raw_spin_unlock_irqrestore(&desc->lock, flags);
1640
1641         unregister_handler_proc(irq, action);
1642
1643         module_put(desc->owner);
1644         return action;
1645
1646 bad:
1647         raw_spin_unlock_irqrestore(&desc->lock, flags);
1648         return NULL;
1649 }
1650
1651 /**
1652  *      remove_percpu_irq - free a per-cpu interrupt
1653  *      @irq: Interrupt line to free
1654  *      @act: irqaction for the interrupt
1655  *
1656  * Used to remove interrupts statically setup by the early boot process.
1657  */
1658 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1659 {
1660         struct irq_desc *desc = irq_to_desc(irq);
1661
1662         if (desc && irq_settings_is_per_cpu_devid(desc))
1663             __free_percpu_irq(irq, act->percpu_dev_id);
1664 }
1665
1666 /**
1667  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1668  *      @irq: Interrupt line to free
1669  *      @dev_id: Device identity to free
1670  *
1671  *      Remove a percpu interrupt handler. The handler is removed, but
1672  *      the interrupt line is not disabled. This must be done on each
1673  *      CPU before calling this function. The function does not return
1674  *      until any executing interrupts for this IRQ have completed.
1675  *
1676  *      This function must not be called from interrupt context.
1677  */
1678 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1679 {
1680         struct irq_desc *desc = irq_to_desc(irq);
1681
1682         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1683                 return;
1684
1685         chip_bus_lock(desc);
1686         kfree(__free_percpu_irq(irq, dev_id));
1687         chip_bus_sync_unlock(desc);
1688 }
1689
1690 /**
1691  *      setup_percpu_irq - setup a per-cpu interrupt
1692  *      @irq: Interrupt line to setup
1693  *      @act: irqaction for the interrupt
1694  *
1695  * Used to statically setup per-cpu interrupts in the early boot process.
1696  */
1697 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1698 {
1699         struct irq_desc *desc = irq_to_desc(irq);
1700         int retval;
1701
1702         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1703                 return -EINVAL;
1704         chip_bus_lock(desc);
1705         retval = __setup_irq(irq, desc, act);
1706         chip_bus_sync_unlock(desc);
1707
1708         return retval;
1709 }
1710
1711 /**
1712  *      request_percpu_irq - allocate a percpu interrupt line
1713  *      @irq: Interrupt line to allocate
1714  *      @handler: Function to be called when the IRQ occurs.
1715  *      @devname: An ascii name for the claiming device
1716  *      @dev_id: A percpu cookie passed back to the handler function
1717  *
1718  *      This call allocates interrupt resources, but doesn't
1719  *      automatically enable the interrupt. It has to be done on each
1720  *      CPU using enable_percpu_irq().
1721  *
1722  *      Dev_id must be globally unique. It is a per-cpu variable, and
1723  *      the handler gets called with the interrupted CPU's instance of
1724  *      that variable.
1725  */
1726 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1727                        const char *devname, void __percpu *dev_id)
1728 {
1729         struct irqaction *action;
1730         struct irq_desc *desc;
1731         int retval;
1732
1733         if (!dev_id)
1734                 return -EINVAL;
1735
1736         desc = irq_to_desc(irq);
1737         if (!desc || !irq_settings_can_request(desc) ||
1738             !irq_settings_is_per_cpu_devid(desc))
1739                 return -EINVAL;
1740
1741         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1742         if (!action)
1743                 return -ENOMEM;
1744
1745         action->handler = handler;
1746         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1747         action->name = devname;
1748         action->percpu_dev_id = dev_id;
1749
1750         chip_bus_lock(desc);
1751         retval = __setup_irq(irq, desc, action);
1752         chip_bus_sync_unlock(desc);
1753
1754         if (retval)
1755                 kfree(action);
1756
1757         return retval;
1758 }