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, false);
 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 {
 197         struct irq_chip *chip = irq_data_get_irq_chip(data);
 198         struct irq_desc *desc = irq_data_to_desc(data);
 199         int ret = 0;
 200
 201         if (!chip || !chip->irq_set_affinity)
 202                 return -EINVAL;
 203
 204         if (irq_can_move_pcntxt(data)) {
 205                 ret = irq_do_set_affinity(data, mask, false);
 206         } else {
 207                 irqd_set_move_pending(data);
 208                 irq_copy_pending(desc, mask);
 209         }
 210
 211         if (desc->affinity_notify) {
 212                 kref_get(&desc->affinity_notify->kref);
 213                 schedule_work(&desc->affinity_notify->work);
 214         }
 215         irqd_set(data, IRQD_AFFINITY_SET);
 216
 217         return ret;
 218 }
 219
 220 /**
 221  *      irq_set_affinity - Set the irq affinity of a given irq
 222  *      @irq:           Interrupt to set affinity
 223  *      @mask:          cpumask
 224  *
 225  */
 226 int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
 227 {
 228         struct irq_desc *desc = irq_to_desc(irq);
 229         unsigned long flags;
 230         int ret;
 231
 232         if (!desc)
 233                 return -EINVAL;
 234
 235         raw_spin_lock_irqsave(&desc->lock, flags);
 236         ret =  __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
 237         raw_spin_unlock_irqrestore(&desc->lock, flags);
 238         return ret;
 239 }
 240
 241 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 242 {
 243         unsigned long flags;
 244         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 245
 246         if (!desc)
 247                 return -EINVAL;
 248         desc->affinity_hint = m;
 249         irq_put_desc_unlock(desc, flags);
 250         return 0;
 251 }
 252 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
 253
 254 static void irq_affinity_notify(struct work_struct *work)
 255 {
 256         struct irq_affinity_notify *notify =
 257                 container_of(work, struct irq_affinity_notify, work);
 258         struct irq_desc *desc = irq_to_desc(notify->irq);
 259         cpumask_var_t cpumask;
 260         unsigned long flags;
 261
 262         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
 263                 goto out;
 264
 265         raw_spin_lock_irqsave(&desc->lock, flags);
 266         if (irq_move_pending(&desc->irq_data))
 267                 irq_get_pending(cpumask, desc);
 268         else
 269                 cpumask_copy(cpumask, desc->irq_data.affinity);
 270         raw_spin_unlock_irqrestore(&desc->lock, flags);
 271
 272         notify->notify(notify, cpumask);
 273
 274         free_cpumask_var(cpumask);
 275 out:
 276         kref_put(&notify->kref, notify->release);
 277 }
 278
 279 /**
 280  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
 281  *      @irq:           Interrupt for which to enable/disable notification
 282  *      @notify:        Context for notification, or %NULL to disable
 283  *                      notification.  Function pointers must be initialised;
 284  *                      the other fields will be initialised by this function.
 285  *
 286  *      Must be called in process context.  Notification may only be enabled
 287  *      after the IRQ is allocated and must be disabled before the IRQ is
 288  *      freed using free_irq().
 289  */
 290 int
 291 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 292 {
 293         struct irq_desc *desc = irq_to_desc(irq);
 294         struct irq_affinity_notify *old_notify;
 295         unsigned long flags;
 296
 297         /* The release function is promised process context */
 298         might_sleep();
 299
 300         if (!desc)
 301                 return -EINVAL;
 302
 303         /* Complete initialisation of *notify */
 304         if (notify) {
 305                 notify->irq = irq;
 306                 kref_init(&notify->kref);
 307                 INIT_WORK(&notify->work, irq_affinity_notify);
 308         }
 309
 310         raw_spin_lock_irqsave(&desc->lock, flags);
 311         old_notify = desc->affinity_notify;
 312         desc->affinity_notify = notify;
 313         raw_spin_unlock_irqrestore(&desc->lock, flags);
 314
 315         if (old_notify)
 316                 kref_put(&old_notify->kref, old_notify->release);
 317
 318         return 0;
 319 }
 320 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
 321
 322 #ifndef CONFIG_AUTO_IRQ_AFFINITY
 323 /*
 324  * Generic version of the affinity autoselector.
 325  */
 326 static int
 327 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 328 {
 329         struct cpumask *set = irq_default_affinity;
 330         int node = desc->irq_data.node;
 331
 332         /* Excludes PER_CPU and NO_BALANCE interrupts */
 333         if (!irq_can_set_affinity(irq))
 334                 return 0;
 335
 336         /*
 337          * Preserve an userspace affinity setup, but make sure that
 338          * one of the targets is online.
 339          */
 340         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
 341                 if (cpumask_intersects(desc->irq_data.affinity,
 342                                        cpu_online_mask))
 343                         set = desc->irq_data.affinity;
 344                 else
 345                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 346         }
 347
 348         cpumask_and(mask, cpu_online_mask, set);
 349         if (node != NUMA_NO_NODE) {
 350                 const struct cpumask *nodemask = cpumask_of_node(node);
 351
 352                 /* make sure at least one of the cpus in nodemask is online */
 353                 if (cpumask_intersects(mask, nodemask))
 354                         cpumask_and(mask, mask, nodemask);
 355         }
 356         irq_do_set_affinity(&desc->irq_data, mask, false);
 357         return 0;
 358 }
 359 #else
 360 static inline int
 361 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
 362 {
 363         return irq_select_affinity(irq);
 364 }
 365 #endif
 366
 367 /*
 368  * Called when affinity is set via /proc/irq
 369  */
 370 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
 371 {
 372         struct irq_desc *desc = irq_to_desc(irq);
 373         unsigned long flags;
 374         int ret;
 375
 376         raw_spin_lock_irqsave(&desc->lock, flags);
 377         ret = setup_affinity(irq, desc, mask);
 378         raw_spin_unlock_irqrestore(&desc->lock, flags);
 379         return ret;
 380 }
 381
 382 #else
 383 static inline int
 384 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 385 {
 386         return 0;
 387 }
 388 #endif
 389
 390 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
 391 {
 392         if (suspend) {
 393                 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
 394                         return;
 395                 desc->istate |= IRQS_SUSPENDED;
 396         }
 397
 398         if (!desc->depth++)
 399                 irq_disable(desc);
 400 }
 401
 402 static int __disable_irq_nosync(unsigned int irq)
 403 {
 404         unsigned long flags;
 405         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 406
 407         if (!desc)
 408                 return -EINVAL;
 409         __disable_irq(desc, irq, false);
 410         irq_put_desc_busunlock(desc, flags);
 411         return 0;
 412 }
 413
 414 /**
 415  *      disable_irq_nosync - disable an irq without waiting
 416  *      @irq: Interrupt to disable
 417  *
 418  *      Disable the selected interrupt line.  Disables and Enables are
 419  *      nested.
 420  *      Unlike disable_irq(), this function does not ensure existing
 421  *      instances of the IRQ handler have completed before returning.
 422  *
 423  *      This function may be called from IRQ context.
 424  */
 425 void disable_irq_nosync(unsigned int irq)
 426 {
 427         __disable_irq_nosync(irq);
 428 }
 429 EXPORT_SYMBOL(disable_irq_nosync);
 430
 431 /**
 432  *      disable_irq - disable an irq and wait for completion
 433  *      @irq: Interrupt to disable
 434  *
 435  *      Disable the selected interrupt line.  Enables and Disables are
 436  *      nested.
 437  *      This function waits for any pending IRQ handlers for this interrupt
 438  *      to complete before returning. If you use this function while
 439  *      holding a resource the IRQ handler may need you will deadlock.
 440  *
 441  *      This function may be called - with care - from IRQ context.
 442  */
 443 void disable_irq(unsigned int irq)
 444 {
 445         if (!__disable_irq_nosync(irq))
 446                 synchronize_irq(irq);
 447 }
 448 EXPORT_SYMBOL(disable_irq);
 449
 450 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
 451 {
 452         if (resume) {
 453                 if (!(desc->istate & IRQS_SUSPENDED)) {
 454                         if (!desc->action)
 455                                 return;
 456                         if (!(desc->action->flags & IRQF_FORCE_RESUME))
 457                                 return;
 458                         /* Pretend that it got disabled ! */
 459                         desc->depth++;
 460                 }
 461                 desc->istate &= ~IRQS_SUSPENDED;
 462         }
 463
 464         switch (desc->depth) {
 465         case 0:
 466  err_out:
 467                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
 468                 break;
 469         case 1: {
 470                 if (desc->istate & IRQS_SUSPENDED)
 471                         goto err_out;
 472                 /* Prevent probing on this irq: */
 473                 irq_settings_set_noprobe(desc);
 474                 irq_enable(desc);
 475                 check_irq_resend(desc, irq);
 476                 /* fall-through */
 477         }
 478         default:
 479                 desc->depth--;
 480         }
 481 }
 482
 483 /**
 484  *      enable_irq - enable handling of an irq
 485  *      @irq: Interrupt to enable
 486  *
 487  *      Undoes the effect of one call to disable_irq().  If this
 488  *      matches the last disable, processing of interrupts on this
 489  *      IRQ line is re-enabled.
 490  *
 491  *      This function may be called from IRQ context only when
 492  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
 493  */
 494 void enable_irq(unsigned int irq)
 495 {
 496         unsigned long flags;
 497         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 498
 499         if (!desc)
 500                 return;
 501         if (WARN(!desc->irq_data.chip,
 502                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
 503                 goto out;
 504
 505         __enable_irq(desc, irq, false);
 506 out:
 507         irq_put_desc_busunlock(desc, flags);
 508 }
 509 EXPORT_SYMBOL(enable_irq);
 510
 511 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 512 {
 513         struct irq_desc *desc = irq_to_desc(irq);
 514         int ret = -ENXIO;
 515
 516         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 517                 return 0;
 518
 519         if (desc->irq_data.chip->irq_set_wake)
 520                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
 521
 522         return ret;
 523 }
 524
 525 /**
 526  *      irq_set_irq_wake - control irq power management wakeup
 527  *      @irq:   interrupt to control
 528  *      @on:    enable/disable power management wakeup
 529  *
 530  *      Enable/disable power management wakeup mode, which is
 531  *      disabled by default.  Enables and disables must match,
 532  *      just as they match for non-wakeup mode support.
 533  *
 534  *      Wakeup mode lets this IRQ wake the system from sleep
 535  *      states like "suspend to RAM".
 536  */
 537 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 538 {
 539         unsigned long flags;
 540         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 541         int ret = 0;
 542
 543         if (!desc)
 544                 return -EINVAL;
 545
 546         /* wakeup-capable irqs can be shared between drivers that
 547          * don't need to have the same sleep mode behaviors.
 548          */
 549         if (on) {
 550                 if (desc->wake_depth++ == 0) {
 551                         ret = set_irq_wake_real(irq, on);
 552                         if (ret)
 553                                 desc->wake_depth = 0;
 554                         else
 555                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 556                 }
 557         } else {
 558                 if (desc->wake_depth == 0) {
 559                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 560                 } else if (--desc->wake_depth == 0) {
 561                         ret = set_irq_wake_real(irq, on);
 562                         if (ret)
 563                                 desc->wake_depth = 1;
 564                         else
 565                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 566                 }
 567         }
 568         irq_put_desc_busunlock(desc, flags);
 569         return ret;
 570 }
 571 EXPORT_SYMBOL(irq_set_irq_wake);
 572
 573 /*
 574  * Internal function that tells the architecture code whether a
 575  * particular irq has been exclusively allocated or is available
 576  * for driver use.
 577  */
 578 int can_request_irq(unsigned int irq, unsigned long irqflags)
 579 {
 580         unsigned long flags;
 581         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 582         int canrequest = 0;
 583
 584         if (!desc)
 585                 return 0;
 586
 587         if (irq_settings_can_request(desc)) {
 588                 if (!desc->action ||
 589                     irqflags & desc->action->flags & IRQF_SHARED)
 590                         canrequest = 1;
 591         }
 592         irq_put_desc_unlock(desc, flags);
 593         return canrequest;
 594 }
 595
 596 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 597                       unsigned long flags)
 598 {
 599         struct irq_chip *chip = desc->irq_data.chip;
 600         int ret, unmask = 0;
 601
 602         if (!chip || !chip->irq_set_type) {
 603                 /*
 604                  * IRQF_TRIGGER_* but the PIC does not support multiple
 605                  * flow-types?
 606                  */
 607                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
 608                          chip ? (chip->name ? : "unknown") : "unknown");
 609                 return 0;
 610         }
 611
 612         flags &= IRQ_TYPE_SENSE_MASK;
 613
 614         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 615                 if (!irqd_irq_masked(&desc->irq_data))
 616                         mask_irq(desc);
 617                 if (!irqd_irq_disabled(&desc->irq_data))
 618                         unmask = 1;
 619         }
 620
 621         /* caller masked out all except trigger mode flags */
 622         ret = chip->irq_set_type(&desc->irq_data, flags);
 623
 624         switch (ret) {
 625         case IRQ_SET_MASK_OK:
 626                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 627                 irqd_set(&desc->irq_data, flags);
 628
 629         case IRQ_SET_MASK_OK_NOCOPY:
 630                 flags = irqd_get_trigger_type(&desc->irq_data);
 631                 irq_settings_set_trigger_mask(desc, flags);
 632                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
 633                 irq_settings_clr_level(desc);
 634                 if (flags & IRQ_TYPE_LEVEL_MASK) {
 635                         irq_settings_set_level(desc);
 636                         irqd_set(&desc->irq_data, IRQD_LEVEL);
 637                 }
 638
 639                 ret = 0;
 640                 break;
 641         default:
 642                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
 643                        flags, irq, chip->irq_set_type);
 644         }
 645         if (unmask)
 646                 unmask_irq(desc);
 647         return ret;
 648 }
 649
 650 #ifdef CONFIG_HARDIRQS_SW_RESEND
 651 int irq_set_parent(int irq, int parent_irq)
 652 {
 653         unsigned long flags;
 654         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 655
 656         if (!desc)
 657                 return -EINVAL;
 658
 659         desc->parent_irq = parent_irq;
 660
 661         irq_put_desc_unlock(desc, flags);
 662         return 0;
 663 }
 664 #endif
 665
 666 /*
 667  * Default primary interrupt handler for threaded interrupts. Is
 668  * assigned as primary handler when request_threaded_irq is called
 669  * with handler == NULL. Useful for oneshot interrupts.
 670  */
 671 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 672 {
 673         return IRQ_WAKE_THREAD;
 674 }
 675
 676 /*
 677  * Primary handler for nested threaded interrupts. Should never be
 678  * called.
 679  */
 680 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 681 {
 682         WARN(1, "Primary handler called for nested irq %d\n", irq);
 683         return IRQ_NONE;
 684 }
 685
 686 static int irq_wait_for_interrupt(struct irqaction *action)
 687 {
 688         set_current_state(TASK_INTERRUPTIBLE);
 689
 690         while (!kthread_should_stop()) {
 691
 692                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
 693                                        &action->thread_flags)) {
 694                         __set_current_state(TASK_RUNNING);
 695                         return 0;
 696                 }
 697                 schedule();
 698                 set_current_state(TASK_INTERRUPTIBLE);
 699         }
 700         __set_current_state(TASK_RUNNING);
 701         return -1;
 702 }
 703
 704 /*
 705  * Oneshot interrupts keep the irq line masked until the threaded
 706  * handler finished. unmask if the interrupt has not been disabled and
 707  * is marked MASKED.
 708  */
 709 static void irq_finalize_oneshot(struct irq_desc *desc,
 710                                  struct irqaction *action)
 711 {
 712         if (!(desc->istate & IRQS_ONESHOT))
 713                 return;
 714 again:
 715         chip_bus_lock(desc);
 716         raw_spin_lock_irq(&desc->lock);
 717
 718         /*
 719          * Implausible though it may be we need to protect us against
 720          * the following scenario:
 721          *
 722          * The thread is faster done than the hard interrupt handler
 723          * on the other CPU. If we unmask the irq line then the
 724          * interrupt can come in again and masks the line, leaves due
 725          * to IRQS_INPROGRESS and the irq line is masked forever.
 726          *
 727          * This also serializes the state of shared oneshot handlers
 728          * versus "desc->threads_onehsot |= action->thread_mask;" in
 729          * irq_wake_thread(). See the comment there which explains the
 730          * serialization.
 731          */
 732         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 733                 raw_spin_unlock_irq(&desc->lock);
 734                 chip_bus_sync_unlock(desc);
 735                 cpu_relax();
 736                 goto again;
 737         }
 738
 739         /*
 740          * Now check again, whether the thread should run. Otherwise
 741          * we would clear the threads_oneshot bit of this thread which
 742          * was just set.
 743          */
 744         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 745                 goto out_unlock;
 746
 747         desc->threads_oneshot &= ~action->thread_mask;
 748
 749         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 750             irqd_irq_masked(&desc->irq_data))
 751                 unmask_threaded_irq(desc);
 752
 753 out_unlock:
 754         raw_spin_unlock_irq(&desc->lock);
 755         chip_bus_sync_unlock(desc);
 756 }
 757
 758 #ifdef CONFIG_SMP
 759 /*
 760  * Check whether we need to change the affinity of the interrupt thread.
 761  */
 762 static void
 763 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 764 {
 765         cpumask_var_t mask;
 766         bool valid = true;
 767
 768         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 769                 return;
 770
 771         /*
 772          * In case we are out of memory we set IRQTF_AFFINITY again and
 773          * try again next time
 774          */
 775         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 776                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
 777                 return;
 778         }
 779
 780         raw_spin_lock_irq(&desc->lock);
 781         /*
 782          * This code is triggered unconditionally. Check the affinity
 783          * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
 784          */
 785         if (desc->irq_data.affinity)
 786                 cpumask_copy(mask, desc->irq_data.affinity);
 787         else
 788                 valid = false;
 789         raw_spin_unlock_irq(&desc->lock);
 790
 791         if (valid)
 792                 set_cpus_allowed_ptr(current, mask);
 793         free_cpumask_var(mask);
 794 }
 795 #else
 796 static inline void
 797 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 798 #endif
 799
 800 /*
 801  * Interrupts which are not explicitely requested as threaded
 802  * interrupts rely on the implicit bh/preempt disable of the hard irq
 803  * context. So we need to disable bh here to avoid deadlocks and other
 804  * side effects.
 805  */
 806 static irqreturn_t
 807 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 808 {
 809         irqreturn_t ret;
 810
 811         local_bh_disable();
 812         ret = action->thread_fn(action->irq, action->dev_id);
 813         irq_finalize_oneshot(desc, action);
 814         local_bh_enable();
 815         return ret;
 816 }
 817
 818 /*
 819  * Interrupts explicitly requested as threaded interrupts want to be
 820  * preemtible - many of them need to sleep and wait for slow busses to
 821  * complete.
 822  */
 823 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 824                 struct irqaction *action)
 825 {
 826         irqreturn_t ret;
 827
 828         ret = action->thread_fn(action->irq, action->dev_id);
 829         irq_finalize_oneshot(desc, action);
 830         return ret;
 831 }
 832
 833 static void wake_threads_waitq(struct irq_desc *desc)
 834 {
 835         if (atomic_dec_and_test(&desc->threads_active))
 836                 wake_up(&desc->wait_for_threads);
 837 }
 838
 839 static void irq_thread_dtor(struct callback_head *unused)
 840 {
 841         struct task_struct *tsk = current;
 842         struct irq_desc *desc;
 843         struct irqaction *action;
 844
 845         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
 846                 return;
 847
 848         action = kthread_data(tsk);
 849
 850         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 851                tsk->comm, tsk->pid, action->irq);
 852
 853
 854         desc = irq_to_desc(action->irq);
 855         /*
 856          * If IRQTF_RUNTHREAD is set, we need to decrement
 857          * desc->threads_active and wake possible waiters.
 858          */
 859         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 860                 wake_threads_waitq(desc);
 861
 862         /* Prevent a stale desc->threads_oneshot */
 863         irq_finalize_oneshot(desc, action);
 864 }
 865
 866 /*
 867  * Interrupt handler thread
 868  */
 869 static int irq_thread(void *data)
 870 {
 871         struct callback_head on_exit_work;
 872         struct irqaction *action = data;
 873         struct irq_desc *desc = irq_to_desc(action->irq);
 874         irqreturn_t (*handler_fn)(struct irq_desc *desc,
 875                         struct irqaction *action);
 876
 877         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 878                                         &action->thread_flags))
 879                 handler_fn = irq_forced_thread_fn;
 880         else
 881                 handler_fn = irq_thread_fn;
 882
 883         init_task_work(&on_exit_work, irq_thread_dtor);
 884         task_work_add(current, &on_exit_work, false);
 885
 886         irq_thread_check_affinity(desc, action);
 887
 888         while (!irq_wait_for_interrupt(action)) {
 889                 irqreturn_t action_ret;
 890
 891                 irq_thread_check_affinity(desc, action);
 892
 893                 action_ret = handler_fn(desc, action);
 894                 if (!noirqdebug)
 895                         note_interrupt(action->irq, desc, action_ret);
 896
 897                 wake_threads_waitq(desc);
 898         }
 899
 900         /*
 901          * This is the regular exit path. __free_irq() is stopping the
 902          * thread via kthread_stop() after calling
 903          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
 904          * oneshot mask bit can be set. We cannot verify that as we
 905          * cannot touch the oneshot mask at this point anymore as
 906          * __setup_irq() might have given out currents thread_mask
 907          * again.
 908          */
 909         task_work_cancel(current, irq_thread_dtor);
 910         return 0;
 911 }
 912
 913 /**
 914  *      irq_wake_thread - wake the irq thread for the action identified by dev_id
 915  *      @irq:           Interrupt line
 916  *      @dev_id:        Device identity for which the thread should be woken
 917  *
 918  */
 919 void irq_wake_thread(unsigned int irq, void *dev_id)
 920 {
 921         struct irq_desc *desc = irq_to_desc(irq);
 922         struct irqaction *action;
 923         unsigned long flags;
 924
 925         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
 926                 return;
 927
 928         raw_spin_lock_irqsave(&desc->lock, flags);
 929         for (action = desc->action; action; action = action->next) {
 930                 if (action->dev_id == dev_id) {
 931                         if (action->thread)
 932                                 __irq_wake_thread(desc, action);
 933                         break;
 934                 }
 935         }
 936         raw_spin_unlock_irqrestore(&desc->lock, flags);
 937 }
 938 EXPORT_SYMBOL_GPL(irq_wake_thread);
 939
 940 static void irq_setup_forced_threading(struct irqaction *new)
 941 {
 942         if (!force_irqthreads)
 943                 return;
 944         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 945                 return;
 946
 947         new->flags |= IRQF_ONESHOT;
 948
 949         if (!new->thread_fn) {
 950                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 951                 new->thread_fn = new->handler;
 952                 new->handler = irq_default_primary_handler;
 953         }
 954 }
 955
 956 static int irq_request_resources(struct irq_desc *desc)
 957 {
 958         struct irq_data *d = &desc->irq_data;
 959         struct irq_chip *c = d->chip;
 960
 961         return c->irq_request_resources ? c->irq_request_resources(d) : 0;
 962 }
 963
 964 static void irq_release_resources(struct irq_desc *desc)
 965 {
 966         struct irq_data *d = &desc->irq_data;
 967         struct irq_chip *c = d->chip;
 968
 969         if (c->irq_release_resources)
 970                 c->irq_release_resources(d);
 971 }
 972
 973 /*
 974  * Internal function to register an irqaction - typically used to
 975  * allocate special interrupts that are part of the architecture.
 976  */
 977 static int
 978 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 979 {
 980         struct irqaction *old, **old_ptr;
 981         unsigned long flags, thread_mask = 0;
 982         int ret, nested, shared = 0;
 983         cpumask_var_t mask;
 984
 985         if (!desc)
 986                 return -EINVAL;
 987
 988         if (desc->irq_data.chip == &no_irq_chip)
 989                 return -ENOSYS;
 990         if (!try_module_get(desc->owner))
 991                 return -ENODEV;
 992
 993         /*
 994          * Check whether the interrupt nests into another interrupt
 995          * thread.
 996          */
 997         nested = irq_settings_is_nested_thread(desc);
 998         if (nested) {
 999                 if (!new->thread_fn) {
1000                         ret = -EINVAL;
1001                         goto out_mput;
1002                 }
1003                 /*
1004                  * Replace the primary handler which was provided from
1005                  * the driver for non nested interrupt handling by the
1006                  * dummy function which warns when called.
1007                  */
1008                 new->handler = irq_nested_primary_handler;
1009         } else {
1010                 if (irq_settings_can_thread(desc))
1011                         irq_setup_forced_threading(new);
1012         }
1013
1014         /*
1015          * Create a handler thread when a thread function is supplied
1016          * and the interrupt does not nest into another interrupt
1017          * thread.
1018          */
1019         if (new->thread_fn && !nested) {
1020                 struct task_struct *t;
1021                 static const struct sched_param param = {
1022                         .sched_priority = MAX_USER_RT_PRIO/2,
1023                 };
1024
1025                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1026                                    new->name);
1027                 if (IS_ERR(t)) {
1028                         ret = PTR_ERR(t);
1029                         goto out_mput;
1030                 }
1031
1032                 sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
1033
1034                 /*
1035                  * We keep the reference to the task struct even if
1036                  * the thread dies to avoid that the interrupt code
1037                  * references an already freed task_struct.
1038                  */
1039                 get_task_struct(t);
1040                 new->thread = t;
1041                 /*
1042                  * Tell the thread to set its affinity. This is
1043                  * important for shared interrupt handlers as we do
1044                  * not invoke setup_affinity() for the secondary
1045                  * handlers as everything is already set up. Even for
1046                  * interrupts marked with IRQF_NO_BALANCE this is
1047                  * correct as we want the thread to move to the cpu(s)
1048                  * on which the requesting code placed the interrupt.
1049                  */
1050                 set_bit(IRQTF_AFFINITY, &new->thread_flags);
1051         }
1052
1053         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1054                 ret = -ENOMEM;
1055                 goto out_thread;
1056         }
1057
1058         /*
1059          * Drivers are often written to work w/o knowledge about the
1060          * underlying irq chip implementation, so a request for a
1061          * threaded irq without a primary hard irq context handler
1062          * requires the ONESHOT flag to be set. Some irq chips like
1063          * MSI based interrupts are per se one shot safe. Check the
1064          * chip flags, so we can avoid the unmask dance at the end of
1065          * the threaded handler for those.
1066          */
1067         if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1068                 new->flags &= ~IRQF_ONESHOT;
1069
1070         /*
1071          * The following block of code has to be executed atomically
1072          */
1073         raw_spin_lock_irqsave(&desc->lock, flags);
1074         old_ptr = &desc->action;
1075         old = *old_ptr;
1076         if (old) {
1077                 /*
1078                  * Can't share interrupts unless both agree to and are
1079                  * the same type (level, edge, polarity). So both flag
1080                  * fields must have IRQF_SHARED set and the bits which
1081                  * set the trigger type must match. Also all must
1082                  * agree on ONESHOT.
1083                  */
1084                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1085                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1086                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
1087                         goto mismatch;
1088
1089                 /* All handlers must agree on per-cpuness */
1090                 if ((old->flags & IRQF_PERCPU) !=
1091                     (new->flags & IRQF_PERCPU))
1092                         goto mismatch;
1093
1094                 /* add new interrupt at end of irq queue */
1095                 do {
1096                         /*
1097                          * Or all existing action->thread_mask bits,
1098                          * so we can find the next zero bit for this
1099                          * new action.
1100                          */
1101                         thread_mask |= old->thread_mask;
1102                         old_ptr = &old->next;
1103                         old = *old_ptr;
1104                 } while (old);
1105                 shared = 1;
1106         }
1107
1108         /*
1109          * Setup the thread mask for this irqaction for ONESHOT. For
1110          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1111          * conditional in irq_wake_thread().
1112          */
1113         if (new->flags & IRQF_ONESHOT) {
1114                 /*
1115                  * Unlikely to have 32 resp 64 irqs sharing one line,
1116                  * but who knows.
1117                  */
1118                 if (thread_mask == ~0UL) {
1119                         ret = -EBUSY;
1120                         goto out_mask;
1121                 }
1122                 /*
1123                  * The thread_mask for the action is or'ed to
1124                  * desc->thread_active to indicate that the
1125                  * IRQF_ONESHOT thread handler has been woken, but not
1126                  * yet finished. The bit is cleared when a thread
1127                  * completes. When all threads of a shared interrupt
1128                  * line have completed desc->threads_active becomes
1129                  * zero and the interrupt line is unmasked. See
1130                  * handle.c:irq_wake_thread() for further information.
1131                  *
1132                  * If no thread is woken by primary (hard irq context)
1133                  * interrupt handlers, then desc->threads_active is
1134                  * also checked for zero to unmask the irq line in the
1135                  * affected hard irq flow handlers
1136                  * (handle_[fasteoi|level]_irq).
1137                  *
1138                  * The new action gets the first zero bit of
1139                  * thread_mask assigned. See the loop above which or's
1140                  * all existing action->thread_mask bits.
1141                  */
1142                 new->thread_mask = 1 << ffz(thread_mask);
1143
1144         } else if (new->handler == irq_default_primary_handler &&
1145                    !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1146                 /*
1147                  * The interrupt was requested with handler = NULL, so
1148                  * we use the default primary handler for it. But it
1149                  * does not have the oneshot flag set. In combination
1150                  * with level interrupts this is deadly, because the
1151                  * default primary handler just wakes the thread, then
1152                  * the irq lines is reenabled, but the device still
1153                  * has the level irq asserted. Rinse and repeat....
1154                  *
1155                  * While this works for edge type interrupts, we play
1156                  * it safe and reject unconditionally because we can't
1157                  * say for sure which type this interrupt really
1158                  * has. The type flags are unreliable as the
1159                  * underlying chip implementation can override them.
1160                  */
1161                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1162                        irq);
1163                 ret = -EINVAL;
1164                 goto out_mask;
1165         }
1166
1167         if (!shared) {
1168                 ret = irq_request_resources(desc);
1169                 if (ret) {
1170                         pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1171                                new->name, irq, desc->irq_data.chip->name);
1172                         goto out_mask;
1173                 }
1174
1175                 init_waitqueue_head(&desc->wait_for_threads);
1176
1177                 /* Setup the type (level, edge polarity) if configured: */
1178                 if (new->flags & IRQF_TRIGGER_MASK) {
1179                         ret = __irq_set_trigger(desc, irq,
1180                                         new->flags & IRQF_TRIGGER_MASK);
1181
1182                         if (ret)
1183                                 goto out_mask;
1184                 }
1185
1186                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1187                                   IRQS_ONESHOT | IRQS_WAITING);
1188                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1189
1190                 if (new->flags & IRQF_PERCPU) {
1191                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1192                         irq_settings_set_per_cpu(desc);
1193                 }
1194
1195                 if (new->flags & IRQF_ONESHOT)
1196                         desc->istate |= IRQS_ONESHOT;
1197
1198                 if (irq_settings_can_autoenable(desc))
1199                         irq_startup(desc, true);
1200                 else
1201                         /* Undo nested disables: */
1202                         desc->depth = 1;
1203
1204                 /* Exclude IRQ from balancing if requested */
1205                 if (new->flags & IRQF_NOBALANCING) {
1206                         irq_settings_set_no_balancing(desc);
1207                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1208                 }
1209
1210                 /* Set default affinity mask once everything is setup */
1211                 setup_affinity(irq, desc, mask);
1212
1213         } else if (new->flags & IRQF_TRIGGER_MASK) {
1214                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1215                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1216
1217                 if (nmsk != omsk)
1218                         /* hope the handler works with current  trigger mode */
1219                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1220                                    irq, nmsk, omsk);
1221         }
1222
1223         new->irq = irq;
1224         *old_ptr = new;
1225
1226         /* Reset broken irq detection when installing new handler */
1227         desc->irq_count = 0;
1228         desc->irqs_unhandled = 0;
1229
1230         /*
1231          * Check whether we disabled the irq via the spurious handler
1232          * before. Reenable it and give it another chance.
1233          */
1234         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1235                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1236                 __enable_irq(desc, irq, false);
1237         }
1238
1239         raw_spin_unlock_irqrestore(&desc->lock, flags);
1240
1241         /*
1242          * Strictly no need to wake it up, but hung_task complains
1243          * when no hard interrupt wakes the thread up.
1244          */
1245         if (new->thread)
1246                 wake_up_process(new->thread);
1247
1248         register_irq_proc(irq, desc);
1249         new->dir = NULL;
1250         register_handler_proc(irq, new);
1251         free_cpumask_var(mask);
1252
1253         return 0;
1254
1255 mismatch:
1256         if (!(new->flags & IRQF_PROBE_SHARED)) {
1257                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1258                        irq, new->flags, new->name, old->flags, old->name);
1259 #ifdef CONFIG_DEBUG_SHIRQ
1260                 dump_stack();
1261 #endif
1262         }
1263         ret = -EBUSY;
1264
1265 out_mask:
1266         raw_spin_unlock_irqrestore(&desc->lock, flags);
1267         free_cpumask_var(mask);
1268
1269 out_thread:
1270         if (new->thread) {
1271                 struct task_struct *t = new->thread;
1272
1273                 new->thread = NULL;
1274                 kthread_stop(t);
1275                 put_task_struct(t);
1276         }
1277 out_mput:
1278         module_put(desc->owner);
1279         return ret;
1280 }
1281
1282 /**
1283  *      setup_irq - setup an interrupt
1284  *      @irq: Interrupt line to setup
1285  *      @act: irqaction for the interrupt
1286  *
1287  * Used to statically setup interrupts in the early boot process.
1288  */
1289 int setup_irq(unsigned int irq, struct irqaction *act)
1290 {
1291         int retval;
1292         struct irq_desc *desc = irq_to_desc(irq);
1293
1294         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1295                 return -EINVAL;
1296         chip_bus_lock(desc);
1297         retval = __setup_irq(irq, desc, act);
1298         chip_bus_sync_unlock(desc);
1299
1300         return retval;
1301 }
1302 EXPORT_SYMBOL_GPL(setup_irq);
1303
1304 /*
1305  * Internal function to unregister an irqaction - used to free
1306  * regular and special interrupts that are part of the architecture.
1307  */
1308 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1309 {
1310         struct irq_desc *desc = irq_to_desc(irq);
1311         struct irqaction *action, **action_ptr;
1312         unsigned long flags;
1313
1314         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1315
1316         if (!desc)
1317                 return NULL;
1318
1319         raw_spin_lock_irqsave(&desc->lock, flags);
1320
1321         /*
1322          * There can be multiple actions per IRQ descriptor, find the right
1323          * one based on the dev_id:
1324          */
1325         action_ptr = &desc->action;
1326         for (;;) {
1327                 action = *action_ptr;
1328
1329                 if (!action) {
1330                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1331                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1332
1333                         return NULL;
1334                 }
1335
1336                 if (action->dev_id == dev_id)
1337                         break;
1338                 action_ptr = &action->next;
1339         }
1340
1341         /* Found it - now remove it from the list of entries: */
1342         *action_ptr = action->next;
1343
1344         /* If this was the last handler, shut down the IRQ line: */
1345         if (!desc->action) {
1346                 irq_shutdown(desc);
1347                 irq_release_resources(desc);
1348         }
1349
1350 #ifdef CONFIG_SMP
1351         /* make sure affinity_hint is cleaned up */
1352         if (WARN_ON_ONCE(desc->affinity_hint))
1353                 desc->affinity_hint = NULL;
1354 #endif
1355
1356         raw_spin_unlock_irqrestore(&desc->lock, flags);
1357
1358         unregister_handler_proc(irq, action);
1359
1360         /* Make sure it's not being used on another CPU: */
1361         synchronize_irq(irq);
1362
1363 #ifdef CONFIG_DEBUG_SHIRQ
1364         /*
1365          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1366          * event to happen even now it's being freed, so let's make sure that
1367          * is so by doing an extra call to the handler ....
1368          *
1369          * ( We do this after actually deregistering it, to make sure that a
1370          *   'real' IRQ doesn't run in * parallel with our fake. )
1371          */
1372         if (action->flags & IRQF_SHARED) {
1373                 local_irq_save(flags);
1374                 action->handler(irq, dev_id);
1375                 local_irq_restore(flags);
1376         }
1377 #endif
1378
1379         if (action->thread) {
1380                 kthread_stop(action->thread);
1381                 put_task_struct(action->thread);
1382         }
1383
1384         module_put(desc->owner);
1385         return action;
1386 }
1387
1388 /**
1389  *      remove_irq - free an interrupt
1390  *      @irq: Interrupt line to free
1391  *      @act: irqaction for the interrupt
1392  *
1393  * Used to remove interrupts statically setup by the early boot process.
1394  */
1395 void remove_irq(unsigned int irq, struct irqaction *act)
1396 {
1397         struct irq_desc *desc = irq_to_desc(irq);
1398
1399         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1400             __free_irq(irq, act->dev_id);
1401 }
1402 EXPORT_SYMBOL_GPL(remove_irq);
1403
1404 /**
1405  *      free_irq - free an interrupt allocated with request_irq
1406  *      @irq: Interrupt line to free
1407  *      @dev_id: Device identity to free
1408  *
1409  *      Remove an interrupt handler. The handler is removed and if the
1410  *      interrupt line is no longer in use by any driver it is disabled.
1411  *      On a shared IRQ the caller must ensure the interrupt is disabled
1412  *      on the card it drives before calling this function. The function
1413  *      does not return until any executing interrupts for this IRQ
1414  *      have completed.
1415  *
1416  *      This function must not be called from interrupt context.
1417  */
1418 void free_irq(unsigned int irq, void *dev_id)
1419 {
1420         struct irq_desc *desc = irq_to_desc(irq);
1421
1422         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1423                 return;
1424
1425 #ifdef CONFIG_SMP
1426         if (WARN_ON(desc->affinity_notify))
1427                 desc->affinity_notify = NULL;
1428 #endif
1429
1430         chip_bus_lock(desc);
1431         kfree(__free_irq(irq, dev_id));
1432         chip_bus_sync_unlock(desc);
1433 }
1434 EXPORT_SYMBOL(free_irq);
1435
1436 /**
1437  *      request_threaded_irq - allocate an interrupt line
1438  *      @irq: Interrupt line to allocate
1439  *      @handler: Function to be called when the IRQ occurs.
1440  *                Primary handler for threaded interrupts
1441  *                If NULL and thread_fn != NULL the default
1442  *                primary handler is installed
1443  *      @thread_fn: Function called from the irq handler thread
1444  *                  If NULL, no irq thread is created
1445  *      @irqflags: Interrupt type flags
1446  *      @devname: An ascii name for the claiming device
1447  *      @dev_id: A cookie passed back to the handler function
1448  *
1449  *      This call allocates interrupt resources and enables the
1450  *      interrupt line and IRQ handling. From the point this
1451  *      call is made your handler function may be invoked. Since
1452  *      your handler function must clear any interrupt the board
1453  *      raises, you must take care both to initialise your hardware
1454  *      and to set up the interrupt handler in the right order.
1455  *
1456  *      If you want to set up a threaded irq handler for your device
1457  *      then you need to supply @handler and @thread_fn. @handler is
1458  *      still called in hard interrupt context and has to check
1459  *      whether the interrupt originates from the device. If yes it
1460  *      needs to disable the interrupt on the device and return
1461  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1462  *      @thread_fn. This split handler design is necessary to support
1463  *      shared interrupts.
1464  *
1465  *      Dev_id must be globally unique. Normally the address of the
1466  *      device data structure is used as the cookie. Since the handler
1467  *      receives this value it makes sense to use it.
1468  *
1469  *      If your interrupt is shared you must pass a non NULL dev_id
1470  *      as this is required when freeing the interrupt.
1471  *
1472  *      Flags:
1473  *
1474  *      IRQF_SHARED             Interrupt is shared
1475  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1476  *
1477  */
1478 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1479                          irq_handler_t thread_fn, unsigned long irqflags,
1480                          const char *devname, void *dev_id)
1481 {
1482         struct irqaction *action;
1483         struct irq_desc *desc;
1484         int retval;
1485
1486         /*
1487          * Sanity-check: shared interrupts must pass in a real dev-ID,
1488          * otherwise we'll have trouble later trying to figure out
1489          * which interrupt is which (messes up the interrupt freeing
1490          * logic etc).
1491          */
1492         if ((irqflags & IRQF_SHARED) && !dev_id)
1493                 return -EINVAL;
1494
1495         desc = irq_to_desc(irq);
1496         if (!desc)
1497                 return -EINVAL;
1498
1499         if (!irq_settings_can_request(desc) ||
1500             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1501                 return -EINVAL;
1502
1503         if (!handler) {
1504                 if (!thread_fn)
1505                         return -EINVAL;
1506                 handler = irq_default_primary_handler;
1507         }
1508
1509         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1510         if (!action)
1511                 return -ENOMEM;
1512
1513         action->handler = handler;
1514         action->thread_fn = thread_fn;
1515         action->flags = irqflags;
1516         action->name = devname;
1517         action->dev_id = dev_id;
1518
1519         chip_bus_lock(desc);
1520         retval = __setup_irq(irq, desc, action);
1521         chip_bus_sync_unlock(desc);
1522
1523         if (retval)
1524                 kfree(action);
1525
1526 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1527         if (!retval && (irqflags & IRQF_SHARED)) {
1528                 /*
1529                  * It's a shared IRQ -- the driver ought to be prepared for it
1530                  * to happen immediately, so let's make sure....
1531                  * We disable the irq to make sure that a 'real' IRQ doesn't
1532                  * run in parallel with our fake.
1533                  */
1534                 unsigned long flags;
1535
1536                 disable_irq(irq);
1537                 local_irq_save(flags);
1538
1539                 handler(irq, dev_id);
1540
1541                 local_irq_restore(flags);
1542                 enable_irq(irq);
1543         }
1544 #endif
1545         return retval;
1546 }
1547 EXPORT_SYMBOL(request_threaded_irq);
1548
1549 /**
1550  *      request_any_context_irq - allocate an interrupt line
1551  *      @irq: Interrupt line to allocate
1552  *      @handler: Function to be called when the IRQ occurs.
1553  *                Threaded handler for threaded interrupts.
1554  *      @flags: Interrupt type flags
1555  *      @name: An ascii name for the claiming device
1556  *      @dev_id: A cookie passed back to the handler function
1557  *
1558  *      This call allocates interrupt resources and enables the
1559  *      interrupt line and IRQ handling. It selects either a
1560  *      hardirq or threaded handling method depending on the
1561  *      context.
1562  *
1563  *      On failure, it returns a negative value. On success,
1564  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1565  */
1566 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1567                             unsigned long flags, const char *name, void *dev_id)
1568 {
1569         struct irq_desc *desc = irq_to_desc(irq);
1570         int ret;
1571
1572         if (!desc)
1573                 return -EINVAL;
1574
1575         if (irq_settings_is_nested_thread(desc)) {
1576                 ret = request_threaded_irq(irq, NULL, handler,
1577                                            flags, name, dev_id);
1578                 return !ret ? IRQC_IS_NESTED : ret;
1579         }
1580
1581         ret = request_irq(irq, handler, flags, name, dev_id);
1582         return !ret ? IRQC_IS_HARDIRQ : ret;
1583 }
1584 EXPORT_SYMBOL_GPL(request_any_context_irq);
1585
1586 void enable_percpu_irq(unsigned int irq, unsigned int type)
1587 {
1588         unsigned int cpu = smp_processor_id();
1589         unsigned long flags;
1590         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1591
1592         if (!desc)
1593                 return;
1594
1595         type &= IRQ_TYPE_SENSE_MASK;
1596         if (type != IRQ_TYPE_NONE) {
1597                 int ret;
1598
1599                 ret = __irq_set_trigger(desc, irq, type);
1600
1601                 if (ret) {
1602                         WARN(1, "failed to set type for IRQ%d\n", irq);
1603                         goto out;
1604                 }
1605         }
1606
1607         irq_percpu_enable(desc, cpu);
1608 out:
1609         irq_put_desc_unlock(desc, flags);
1610 }
1611 EXPORT_SYMBOL_GPL(enable_percpu_irq);
1612
1613 void disable_percpu_irq(unsigned int irq)
1614 {
1615         unsigned int cpu = smp_processor_id();
1616         unsigned long flags;
1617         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1618
1619         if (!desc)
1620                 return;
1621
1622         irq_percpu_disable(desc, cpu);
1623         irq_put_desc_unlock(desc, flags);
1624 }
1625 EXPORT_SYMBOL_GPL(disable_percpu_irq);
1626
1627 /*
1628  * Internal function to unregister a percpu irqaction.
1629  */
1630 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1631 {
1632         struct irq_desc *desc = irq_to_desc(irq);
1633         struct irqaction *action;
1634         unsigned long flags;
1635
1636         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1637
1638         if (!desc)
1639                 return NULL;
1640
1641         raw_spin_lock_irqsave(&desc->lock, flags);
1642
1643         action = desc->action;
1644         if (!action || action->percpu_dev_id != dev_id) {
1645                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1646                 goto bad;
1647         }
1648
1649         if (!cpumask_empty(desc->percpu_enabled)) {
1650                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1651                      irq, cpumask_first(desc->percpu_enabled));
1652                 goto bad;
1653         }
1654
1655         /* Found it - now remove it from the list of entries: */
1656         desc->action = NULL;
1657
1658         raw_spin_unlock_irqrestore(&desc->lock, flags);
1659
1660         unregister_handler_proc(irq, action);
1661
1662         module_put(desc->owner);
1663         return action;
1664
1665 bad:
1666         raw_spin_unlock_irqrestore(&desc->lock, flags);
1667         return NULL;
1668 }
1669
1670 /**
1671  *      remove_percpu_irq - free a per-cpu interrupt
1672  *      @irq: Interrupt line to free
1673  *      @act: irqaction for the interrupt
1674  *
1675  * Used to remove interrupts statically setup by the early boot process.
1676  */
1677 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1678 {
1679         struct irq_desc *desc = irq_to_desc(irq);
1680
1681         if (desc && irq_settings_is_per_cpu_devid(desc))
1682             __free_percpu_irq(irq, act->percpu_dev_id);
1683 }
1684
1685 /**
1686  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1687  *      @irq: Interrupt line to free
1688  *      @dev_id: Device identity to free
1689  *
1690  *      Remove a percpu interrupt handler. The handler is removed, but
1691  *      the interrupt line is not disabled. This must be done on each
1692  *      CPU before calling this function. The function does not return
1693  *      until any executing interrupts for this IRQ have completed.
1694  *
1695  *      This function must not be called from interrupt context.
1696  */
1697 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1698 {
1699         struct irq_desc *desc = irq_to_desc(irq);
1700
1701         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1702                 return;
1703
1704         chip_bus_lock(desc);
1705         kfree(__free_percpu_irq(irq, dev_id));
1706         chip_bus_sync_unlock(desc);
1707 }
1708
1709 /**
1710  *      setup_percpu_irq - setup a per-cpu interrupt
1711  *      @irq: Interrupt line to setup
1712  *      @act: irqaction for the interrupt
1713  *
1714  * Used to statically setup per-cpu interrupts in the early boot process.
1715  */
1716 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1717 {
1718         struct irq_desc *desc = irq_to_desc(irq);
1719         int retval;
1720
1721         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1722                 return -EINVAL;
1723         chip_bus_lock(desc);
1724         retval = __setup_irq(irq, desc, act);
1725         chip_bus_sync_unlock(desc);
1726
1727         return retval;
1728 }
1729
1730 /**
1731  *      request_percpu_irq - allocate a percpu interrupt line
1732  *      @irq: Interrupt line to allocate
1733  *      @handler: Function to be called when the IRQ occurs.
1734  *      @devname: An ascii name for the claiming device
1735  *      @dev_id: A percpu cookie passed back to the handler function
1736  *
1737  *      This call allocates interrupt resources, but doesn't
1738  *      automatically enable the interrupt. It has to be done on each
1739  *      CPU using enable_percpu_irq().
1740  *
1741  *      Dev_id must be globally unique. It is a per-cpu variable, and
1742  *      the handler gets called with the interrupted CPU's instance of
1743  *      that variable.
1744  */
1745 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1746                        const char *devname, void __percpu *dev_id)
1747 {
1748         struct irqaction *action;
1749         struct irq_desc *desc;
1750         int retval;
1751
1752         if (!dev_id)
1753                 return -EINVAL;
1754
1755         desc = irq_to_desc(irq);
1756         if (!desc || !irq_settings_can_request(desc) ||
1757             !irq_settings_is_per_cpu_devid(desc))
1758                 return -EINVAL;
1759
1760         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1761         if (!action)
1762                 return -ENOMEM;
1763
1764         action->handler = handler;
1765         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1766         action->name = devname;
1767         action->percpu_dev_id = dev_id;
1768
1769         chip_bus_lock(desc);
1770         retval = __setup_irq(irq, desc, action);
1771         chip_bus_sync_unlock(desc);
1772
1773         if (retval)
1774                 kfree(action);
1775
1776         return retval;
1777 }