root/kernel/irq/manage.c

DEFINITIONS

1. setup_forced_irqthreads
2. __synchronize_hardirq
3. synchronize_hardirq
4. synchronize_irq
5. __irq_can_set_affinity
6. irq_can_set_affinity
7. irq_can_set_affinity_usr
8. irq_set_thread_affinity
9. irq_validate_effective_affinity
10. irq_do_set_affinity
11. irq_set_affinity_pending
12. irq_set_affinity_pending
13. irq_try_set_affinity
14. irq_set_affinity_locked
15. __irq_set_affinity
16. irq_set_affinity_hint
17. irq_affinity_notify
18. irq_set_affinity_notifier
19. irq_setup_affinity
20. irq_setup_affinity
21. irq_set_vcpu_affinity
22. __disable_irq
23. __disable_irq_nosync
24. disable_irq_nosync
25. disable_irq
26. disable_hardirq
27. disable_nmi_nosync
28. __enable_irq
29. enable_irq
30. enable_nmi
31. set_irq_wake_real
32. irq_set_irq_wake
33. can_request_irq
34. __irq_set_trigger
35. irq_set_parent
36. irq_default_primary_handler
37. irq_nested_primary_handler
38. irq_forced_secondary_handler
39. irq_wait_for_interrupt
40. irq_finalize_oneshot
41. irq_thread_check_affinity
42. irq_thread_check_affinity
43. irq_forced_thread_fn
44. irq_thread_fn
45. wake_threads_waitq
46. irq_thread_dtor
47. irq_wake_secondary
48. irq_thread
49. irq_wake_thread
50. irq_setup_forced_threading
51. irq_request_resources
52. irq_release_resources
53. irq_supports_nmi
54. irq_nmi_setup
55. irq_nmi_teardown
56. setup_irq_thread
57. __setup_irq
58. setup_irq
59. __free_irq
60. remove_irq
61. free_irq
62. __cleanup_nmi
63. free_nmi
64. request_threaded_irq
65. request_any_context_irq
66. request_nmi
67. enable_percpu_irq
68. enable_percpu_nmi
69. irq_percpu_is_enabled
70. disable_percpu_irq
71. disable_percpu_nmi
72. __free_percpu_irq
73. remove_percpu_irq
74. free_percpu_irq
75. free_percpu_nmi
76. setup_percpu_irq
77. __request_percpu_irq
78. request_percpu_nmi
79. prepare_percpu_nmi
80. teardown_percpu_nmi
81. __irq_get_irqchip_state
82. irq_get_irqchip_state
83. irq_set_irqchip_state

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   4  * Copyright (C) 2005-2006 Thomas Gleixner
   5  *
   6  * This file contains driver APIs to the irq subsystem.
   7  */
   8 
   9 #define pr_fmt(fmt) "genirq: " fmt
  10 
  11 #include <linux/irq.h>
  12 #include <linux/kthread.h>
  13 #include <linux/module.h>
  14 #include <linux/random.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/irqdomain.h>
  17 #include <linux/slab.h>
  18 #include <linux/sched.h>
  19 #include <linux/sched/rt.h>
  20 #include <linux/sched/task.h>
  21 #include <uapi/linux/sched/types.h>
  22 #include <linux/task_work.h>
  23 
  24 #include "internals.h"
  25 
  26 #if defined(CONFIG_IRQ_FORCED_THREADING) && !defined(CONFIG_PREEMPT_RT)
  27 __read_mostly bool force_irqthreads;
  28 EXPORT_SYMBOL_GPL(force_irqthreads);
  29 
  30 static int __init setup_forced_irqthreads(char *arg)
  31 {
  32         force_irqthreads = true;
  33         return 0;
  34 }
  35 early_param("threadirqs", setup_forced_irqthreads);
  36 #endif
  37 
  38 static void __synchronize_hardirq(struct irq_desc *desc, bool sync_chip)
  39 {
  40         struct irq_data *irqd = irq_desc_get_irq_data(desc);
  41         bool inprogress;
  42 
  43         do {
  44                 unsigned long flags;
  45 
  46                 /*
  47                  * Wait until we're out of the critical section.  This might
  48                  * give the wrong answer due to the lack of memory barriers.
  49                  */
  50                 while (irqd_irq_inprogress(&desc->irq_data))
  51                         cpu_relax();
  52 
  53                 /* Ok, that indicated we're done: double-check carefully. */
  54                 raw_spin_lock_irqsave(&desc->lock, flags);
  55                 inprogress = irqd_irq_inprogress(&desc->irq_data);
  56 
  57                 /*
  58                  * If requested and supported, check at the chip whether it
  59                  * is in flight at the hardware level, i.e. already pending
  60                  * in a CPU and waiting for service and acknowledge.
  61                  */
  62                 if (!inprogress && sync_chip) {
  63                         /*
  64                          * Ignore the return code. inprogress is only updated
  65                          * when the chip supports it.
  66                          */
  67                         __irq_get_irqchip_state(irqd, IRQCHIP_STATE_ACTIVE,
  68                                                 &inprogress);
  69                 }
  70                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  71 
  72                 /* Oops, that failed? */
  73         } while (inprogress);
  74 }
  75 
  76 /**
  77  *      synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
  78  *      @irq: interrupt number to wait for
  79  *
  80  *      This function waits for any pending hard IRQ handlers for this
  81  *      interrupt to complete before returning. If you use this
  82  *      function while holding a resource the IRQ handler may need you
  83  *      will deadlock. It does not take associated threaded handlers
  84  *      into account.
  85  *
  86  *      Do not use this for shutdown scenarios where you must be sure
  87  *      that all parts (hardirq and threaded handler) have completed.
  88  *
  89  *      Returns: false if a threaded handler is active.
  90  *
  91  *      This function may be called - with care - from IRQ context.
  92  *
  93  *      It does not check whether there is an interrupt in flight at the
  94  *      hardware level, but not serviced yet, as this might deadlock when
  95  *      called with interrupts disabled and the target CPU of the interrupt
  96  *      is the current CPU.
  97  */
  98 bool synchronize_hardirq(unsigned int irq)
  99 {
 100         struct irq_desc *desc = irq_to_desc(irq);
 101 
 102         if (desc) {
 103                 __synchronize_hardirq(desc, false);
 104                 return !atomic_read(&desc->threads_active);
 105         }
 106 
 107         return true;
 108 }
 109 EXPORT_SYMBOL(synchronize_hardirq);
 110 
 111 /**
 112  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
 113  *      @irq: interrupt number to wait for
 114  *
 115  *      This function waits for any pending IRQ handlers for this interrupt
 116  *      to complete before returning. If you use this function while
 117  *      holding a resource the IRQ handler may need you will deadlock.
 118  *
 119  *      Can only be called from preemptible code as it might sleep when
 120  *      an interrupt thread is associated to @irq.
 121  *
 122  *      It optionally makes sure (when the irq chip supports that method)
 123  *      that the interrupt is not pending in any CPU and waiting for
 124  *      service.
 125  */
 126 void synchronize_irq(unsigned int irq)
 127 {
 128         struct irq_desc *desc = irq_to_desc(irq);
 129 
 130         if (desc) {
 131                 __synchronize_hardirq(desc, true);
 132                 /*
 133                  * We made sure that no hardirq handler is
 134                  * running. Now verify that no threaded handlers are
 135                  * active.
 136                  */
 137                 wait_event(desc->wait_for_threads,
 138                            !atomic_read(&desc->threads_active));
 139         }
 140 }
 141 EXPORT_SYMBOL(synchronize_irq);
 142 
 143 #ifdef CONFIG_SMP
 144 cpumask_var_t irq_default_affinity;
 145 
 146 static bool __irq_can_set_affinity(struct irq_desc *desc)
 147 {
 148         if (!desc || !irqd_can_balance(&desc->irq_data) ||
 149             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
 150                 return false;
 151         return true;
 152 }
 153 
 154 /**
 155  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
 156  *      @irq:           Interrupt to check
 157  *
 158  */
 159 int irq_can_set_affinity(unsigned int irq)
 160 {
 161         return __irq_can_set_affinity(irq_to_desc(irq));
 162 }
 163 
 164 /**
 165  * irq_can_set_affinity_usr - Check if affinity of a irq can be set from user space
 166  * @irq:        Interrupt to check
 167  *
 168  * Like irq_can_set_affinity() above, but additionally checks for the
 169  * AFFINITY_MANAGED flag.
 170  */
 171 bool irq_can_set_affinity_usr(unsigned int irq)
 172 {
 173         struct irq_desc *desc = irq_to_desc(irq);
 174 
 175         return __irq_can_set_affinity(desc) &&
 176                 !irqd_affinity_is_managed(&desc->irq_data);
 177 }
 178 
 179 /**
 180  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
 181  *      @desc:          irq descriptor which has affitnity changed
 182  *
 183  *      We just set IRQTF_AFFINITY and delegate the affinity setting
 184  *      to the interrupt thread itself. We can not call
 185  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
 186  *      code can be called from hard interrupt context.
 187  */
 188 void irq_set_thread_affinity(struct irq_desc *desc)
 189 {
 190         struct irqaction *action;
 191 
 192         for_each_action_of_desc(desc, action)
 193                 if (action->thread)
 194                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
 195 }
 196 
 197 static void irq_validate_effective_affinity(struct irq_data *data)
 198 {
 199 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
 200         const struct cpumask *m = irq_data_get_effective_affinity_mask(data);
 201         struct irq_chip *chip = irq_data_get_irq_chip(data);
 202 
 203         if (!cpumask_empty(m))
 204                 return;
 205         pr_warn_once("irq_chip %s did not update eff. affinity mask of irq %u\n",
 206                      chip->name, data->irq);
 207 #endif
 208 }
 209 
 210 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 211                         bool force)
 212 {
 213         struct irq_desc *desc = irq_data_to_desc(data);
 214         struct irq_chip *chip = irq_data_get_irq_chip(data);
 215         int ret;
 216 
 217         if (!chip || !chip->irq_set_affinity)
 218                 return -EINVAL;
 219 
 220         ret = chip->irq_set_affinity(data, mask, force);
 221         switch (ret) {
 222         case IRQ_SET_MASK_OK:
 223         case IRQ_SET_MASK_OK_DONE:
 224                 cpumask_copy(desc->irq_common_data.affinity, mask);
 225                 /* fall through */
 226         case IRQ_SET_MASK_OK_NOCOPY:
 227                 irq_validate_effective_affinity(data);
 228                 irq_set_thread_affinity(desc);
 229                 ret = 0;
 230         }
 231 
 232         return ret;
 233 }
 234 
 235 #ifdef CONFIG_GENERIC_PENDING_IRQ
 236 static inline int irq_set_affinity_pending(struct irq_data *data,
 237                                            const struct cpumask *dest)
 238 {
 239         struct irq_desc *desc = irq_data_to_desc(data);
 240 
 241         irqd_set_move_pending(data);
 242         irq_copy_pending(desc, dest);
 243         return 0;
 244 }
 245 #else
 246 static inline int irq_set_affinity_pending(struct irq_data *data,
 247                                            const struct cpumask *dest)
 248 {
 249         return -EBUSY;
 250 }
 251 #endif
 252 
 253 static int irq_try_set_affinity(struct irq_data *data,
 254                                 const struct cpumask *dest, bool force)
 255 {
 256         int ret = irq_do_set_affinity(data, dest, force);
 257 
 258         /*
 259          * In case that the underlying vector management is busy and the
 260          * architecture supports the generic pending mechanism then utilize
 261          * this to avoid returning an error to user space.
 262          */
 263         if (ret == -EBUSY && !force)
 264                 ret = irq_set_affinity_pending(data, dest);
 265         return ret;
 266 }
 267 
 268 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
 269                             bool force)
 270 {
 271         struct irq_chip *chip = irq_data_get_irq_chip(data);
 272         struct irq_desc *desc = irq_data_to_desc(data);
 273         int ret = 0;
 274 
 275         if (!chip || !chip->irq_set_affinity)
 276                 return -EINVAL;
 277 
 278         if (irq_can_move_pcntxt(data) && !irqd_is_setaffinity_pending(data)) {
 279                 ret = irq_try_set_affinity(data, mask, force);
 280         } else {
 281                 irqd_set_move_pending(data);
 282                 irq_copy_pending(desc, mask);
 283         }
 284 
 285         if (desc->affinity_notify) {
 286                 kref_get(&desc->affinity_notify->kref);
 287                 if (!schedule_work(&desc->affinity_notify->work)) {
 288                         /* Work was already scheduled, drop our extra ref */
 289                         kref_put(&desc->affinity_notify->kref,
 290                                  desc->affinity_notify->release);
 291                 }
 292         }
 293         irqd_set(data, IRQD_AFFINITY_SET);
 294 
 295         return ret;
 296 }
 297 
 298 int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
 299 {
 300         struct irq_desc *desc = irq_to_desc(irq);
 301         unsigned long flags;
 302         int ret;
 303 
 304         if (!desc)
 305                 return -EINVAL;
 306 
 307         raw_spin_lock_irqsave(&desc->lock, flags);
 308         ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
 309         raw_spin_unlock_irqrestore(&desc->lock, flags);
 310         return ret;
 311 }
 312 
 313 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 314 {
 315         unsigned long flags;
 316         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 317 
 318         if (!desc)
 319                 return -EINVAL;
 320         desc->affinity_hint = m;
 321         irq_put_desc_unlock(desc, flags);
 322         /* set the initial affinity to prevent every interrupt being on CPU0 */
 323         if (m)
 324                 __irq_set_affinity(irq, m, false);
 325         return 0;
 326 }
 327 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
 328 
 329 static void irq_affinity_notify(struct work_struct *work)
 330 {
 331         struct irq_affinity_notify *notify =
 332                 container_of(work, struct irq_affinity_notify, work);
 333         struct irq_desc *desc = irq_to_desc(notify->irq);
 334         cpumask_var_t cpumask;
 335         unsigned long flags;
 336 
 337         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
 338                 goto out;
 339 
 340         raw_spin_lock_irqsave(&desc->lock, flags);
 341         if (irq_move_pending(&desc->irq_data))
 342                 irq_get_pending(cpumask, desc);
 343         else
 344                 cpumask_copy(cpumask, desc->irq_common_data.affinity);
 345         raw_spin_unlock_irqrestore(&desc->lock, flags);
 346 
 347         notify->notify(notify, cpumask);
 348 
 349         free_cpumask_var(cpumask);
 350 out:
 351         kref_put(&notify->kref, notify->release);
 352 }
 353 
 354 /**
 355  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
 356  *      @irq:           Interrupt for which to enable/disable notification
 357  *      @notify:        Context for notification, or %NULL to disable
 358  *                      notification.  Function pointers must be initialised;
 359  *                      the other fields will be initialised by this function.
 360  *
 361  *      Must be called in process context.  Notification may only be enabled
 362  *      after the IRQ is allocated and must be disabled before the IRQ is
 363  *      freed using free_irq().
 364  */
 365 int
 366 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 367 {
 368         struct irq_desc *desc = irq_to_desc(irq);
 369         struct irq_affinity_notify *old_notify;
 370         unsigned long flags;
 371 
 372         /* The release function is promised process context */
 373         might_sleep();
 374 
 375         if (!desc || desc->istate & IRQS_NMI)
 376                 return -EINVAL;
 377 
 378         /* Complete initialisation of *notify */
 379         if (notify) {
 380                 notify->irq = irq;
 381                 kref_init(&notify->kref);
 382                 INIT_WORK(&notify->work, irq_affinity_notify);
 383         }
 384 
 385         raw_spin_lock_irqsave(&desc->lock, flags);
 386         old_notify = desc->affinity_notify;
 387         desc->affinity_notify = notify;
 388         raw_spin_unlock_irqrestore(&desc->lock, flags);
 389 
 390         if (old_notify) {
 391                 if (cancel_work_sync(&old_notify->work)) {
 392                         /* Pending work had a ref, put that one too */
 393                         kref_put(&old_notify->kref, old_notify->release);
 394                 }
 395                 kref_put(&old_notify->kref, old_notify->release);
 396         }
 397 
 398         return 0;
 399 }
 400 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
 401 
 402 #ifndef CONFIG_AUTO_IRQ_AFFINITY
 403 /*
 404  * Generic version of the affinity autoselector.
 405  */
 406 int irq_setup_affinity(struct irq_desc *desc)
 407 {
 408         struct cpumask *set = irq_default_affinity;
 409         int ret, node = irq_desc_get_node(desc);
 410         static DEFINE_RAW_SPINLOCK(mask_lock);
 411         static struct cpumask mask;
 412 
 413         /* Excludes PER_CPU and NO_BALANCE interrupts */
 414         if (!__irq_can_set_affinity(desc))
 415                 return 0;
 416 
 417         raw_spin_lock(&mask_lock);
 418         /*
 419          * Preserve the managed affinity setting and a userspace affinity
 420          * setup, but make sure that one of the targets is online.
 421          */
 422         if (irqd_affinity_is_managed(&desc->irq_data) ||
 423             irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
 424                 if (cpumask_intersects(desc->irq_common_data.affinity,
 425                                        cpu_online_mask))
 426                         set = desc->irq_common_data.affinity;
 427                 else
 428                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 429         }
 430 
 431         cpumask_and(&mask, cpu_online_mask, set);
 432         if (cpumask_empty(&mask))
 433                 cpumask_copy(&mask, cpu_online_mask);
 434 
 435         if (node != NUMA_NO_NODE) {
 436                 const struct cpumask *nodemask = cpumask_of_node(node);
 437 
 438                 /* make sure at least one of the cpus in nodemask is online */
 439                 if (cpumask_intersects(&mask, nodemask))
 440                         cpumask_and(&mask, &mask, nodemask);
 441         }
 442         ret = irq_do_set_affinity(&desc->irq_data, &mask, false);
 443         raw_spin_unlock(&mask_lock);
 444         return ret;
 445 }
 446 #else
 447 /* Wrapper for ALPHA specific affinity selector magic */
 448 int irq_setup_affinity(struct irq_desc *desc)
 449 {
 450         return irq_select_affinity(irq_desc_get_irq(desc));
 451 }
 452 #endif /* CONFIG_AUTO_IRQ_AFFINITY */
 453 #endif /* CONFIG_SMP */
 454 
 455 
 456 /**
 457  *      irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
 458  *      @irq: interrupt number to set affinity
 459  *      @vcpu_info: vCPU specific data or pointer to a percpu array of vCPU
 460  *                  specific data for percpu_devid interrupts
 461  *
 462  *      This function uses the vCPU specific data to set the vCPU
 463  *      affinity for an irq. The vCPU specific data is passed from
 464  *      outside, such as KVM. One example code path is as below:
 465  *      KVM -> IOMMU -> irq_set_vcpu_affinity().
 466  */
 467 int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
 468 {
 469         unsigned long flags;
 470         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 471         struct irq_data *data;
 472         struct irq_chip *chip;
 473         int ret = -ENOSYS;
 474 
 475         if (!desc)
 476                 return -EINVAL;
 477 
 478         data = irq_desc_get_irq_data(desc);
 479         do {
 480                 chip = irq_data_get_irq_chip(data);
 481                 if (chip && chip->irq_set_vcpu_affinity)
 482                         break;
 483 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
 484                 data = data->parent_data;
 485 #else
 486                 data = NULL;
 487 #endif
 488         } while (data);
 489 
 490         if (data)
 491                 ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
 492         irq_put_desc_unlock(desc, flags);
 493 
 494         return ret;
 495 }
 496 EXPORT_SYMBOL_GPL(irq_set_vcpu_affinity);
 497 
 498 void __disable_irq(struct irq_desc *desc)
 499 {
 500         if (!desc->depth++)
 501                 irq_disable(desc);
 502 }
 503 
 504 static int __disable_irq_nosync(unsigned int irq)
 505 {
 506         unsigned long flags;
 507         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 508 
 509         if (!desc)
 510                 return -EINVAL;
 511         __disable_irq(desc);
 512         irq_put_desc_busunlock(desc, flags);
 513         return 0;
 514 }
 515 
 516 /**
 517  *      disable_irq_nosync - disable an irq without waiting
 518  *      @irq: Interrupt to disable
 519  *
 520  *      Disable the selected interrupt line.  Disables and Enables are
 521  *      nested.
 522  *      Unlike disable_irq(), this function does not ensure existing
 523  *      instances of the IRQ handler have completed before returning.
 524  *
 525  *      This function may be called from IRQ context.
 526  */
 527 void disable_irq_nosync(unsigned int irq)
 528 {
 529         __disable_irq_nosync(irq);
 530 }
 531 EXPORT_SYMBOL(disable_irq_nosync);
 532 
 533 /**
 534  *      disable_irq - disable an irq and wait for completion
 535  *      @irq: Interrupt to disable
 536  *
 537  *      Disable the selected interrupt line.  Enables and Disables are
 538  *      nested.
 539  *      This function waits for any pending IRQ handlers for this interrupt
 540  *      to complete before returning. If you use this function while
 541  *      holding a resource the IRQ handler may need you will deadlock.
 542  *
 543  *      This function may be called - with care - from IRQ context.
 544  */
 545 void disable_irq(unsigned int irq)
 546 {
 547         if (!__disable_irq_nosync(irq))
 548                 synchronize_irq(irq);
 549 }
 550 EXPORT_SYMBOL(disable_irq);
 551 
 552 /**
 553  *      disable_hardirq - disables an irq and waits for hardirq completion
 554  *      @irq: Interrupt to disable
 555  *
 556  *      Disable the selected interrupt line.  Enables and Disables are
 557  *      nested.
 558  *      This function waits for any pending hard IRQ handlers for this
 559  *      interrupt to complete before returning. If you use this function while
 560  *      holding a resource the hard IRQ handler may need you will deadlock.
 561  *
 562  *      When used to optimistically disable an interrupt from atomic context
 563  *      the return value must be checked.
 564  *
 565  *      Returns: false if a threaded handler is active.
 566  *
 567  *      This function may be called - with care - from IRQ context.
 568  */
 569 bool disable_hardirq(unsigned int irq)
 570 {
 571         if (!__disable_irq_nosync(irq))
 572                 return synchronize_hardirq(irq);
 573 
 574         return false;
 575 }
 576 EXPORT_SYMBOL_GPL(disable_hardirq);
 577 
 578 /**
 579  *      disable_nmi_nosync - disable an nmi without waiting
 580  *      @irq: Interrupt to disable
 581  *
 582  *      Disable the selected interrupt line. Disables and enables are
 583  *      nested.
 584  *      The interrupt to disable must have been requested through request_nmi.
 585  *      Unlike disable_nmi(), this function does not ensure existing
 586  *      instances of the IRQ handler have completed before returning.
 587  */
 588 void disable_nmi_nosync(unsigned int irq)
 589 {
 590         disable_irq_nosync(irq);
 591 }
 592 
 593 void __enable_irq(struct irq_desc *desc)
 594 {
 595         switch (desc->depth) {
 596         case 0:
 597  err_out:
 598                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n",
 599                      irq_desc_get_irq(desc));
 600                 break;
 601         case 1: {
 602                 if (desc->istate & IRQS_SUSPENDED)
 603                         goto err_out;
 604                 /* Prevent probing on this irq: */
 605                 irq_settings_set_noprobe(desc);
 606                 /*
 607                  * Call irq_startup() not irq_enable() here because the
 608                  * interrupt might be marked NOAUTOEN. So irq_startup()
 609                  * needs to be invoked when it gets enabled the first
 610                  * time. If it was already started up, then irq_startup()
 611                  * will invoke irq_enable() under the hood.
 612                  */
 613                 irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
 614                 break;
 615         }
 616         default:
 617                 desc->depth--;
 618         }
 619 }
 620 
 621 /**
 622  *      enable_irq - enable handling of an irq
 623  *      @irq: Interrupt to enable
 624  *
 625  *      Undoes the effect of one call to disable_irq().  If this
 626  *      matches the last disable, processing of interrupts on this
 627  *      IRQ line is re-enabled.
 628  *
 629  *      This function may be called from IRQ context only when
 630  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
 631  */
 632 void enable_irq(unsigned int irq)
 633 {
 634         unsigned long flags;
 635         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 636 
 637         if (!desc)
 638                 return;
 639         if (WARN(!desc->irq_data.chip,
 640                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
 641                 goto out;
 642 
 643         __enable_irq(desc);
 644 out:
 645         irq_put_desc_busunlock(desc, flags);
 646 }
 647 EXPORT_SYMBOL(enable_irq);
 648 
 649 /**
 650  *      enable_nmi - enable handling of an nmi
 651  *      @irq: Interrupt to enable
 652  *
 653  *      The interrupt to enable must have been requested through request_nmi.
 654  *      Undoes the effect of one call to disable_nmi(). If this
 655  *      matches the last disable, processing of interrupts on this
 656  *      IRQ line is re-enabled.
 657  */
 658 void enable_nmi(unsigned int irq)
 659 {
 660         enable_irq(irq);
 661 }
 662 
 663 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 664 {
 665         struct irq_desc *desc = irq_to_desc(irq);
 666         int ret = -ENXIO;
 667 
 668         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 669                 return 0;
 670 
 671         if (desc->irq_data.chip->irq_set_wake)
 672                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
 673 
 674         return ret;
 675 }
 676 
 677 /**
 678  *      irq_set_irq_wake - control irq power management wakeup
 679  *      @irq:   interrupt to control
 680  *      @on:    enable/disable power management wakeup
 681  *
 682  *      Enable/disable power management wakeup mode, which is
 683  *      disabled by default.  Enables and disables must match,
 684  *      just as they match for non-wakeup mode support.
 685  *
 686  *      Wakeup mode lets this IRQ wake the system from sleep
 687  *      states like "suspend to RAM".
 688  */
 689 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 690 {
 691         unsigned long flags;
 692         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 693         int ret = 0;
 694 
 695         if (!desc)
 696                 return -EINVAL;
 697 
 698         /* Don't use NMIs as wake up interrupts please */
 699         if (desc->istate & IRQS_NMI) {
 700                 ret = -EINVAL;
 701                 goto out_unlock;
 702         }
 703 
 704         /* wakeup-capable irqs can be shared between drivers that
 705          * don't need to have the same sleep mode behaviors.
 706          */
 707         if (on) {
 708                 if (desc->wake_depth++ == 0) {
 709                         ret = set_irq_wake_real(irq, on);
 710                         if (ret)
 711                                 desc->wake_depth = 0;
 712                         else
 713                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 714                 }
 715         } else {
 716                 if (desc->wake_depth == 0) {
 717                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 718                 } else if (--desc->wake_depth == 0) {
 719                         ret = set_irq_wake_real(irq, on);
 720                         if (ret)
 721                                 desc->wake_depth = 1;
 722                         else
 723                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 724                 }
 725         }
 726 
 727 out_unlock:
 728         irq_put_desc_busunlock(desc, flags);
 729         return ret;
 730 }
 731 EXPORT_SYMBOL(irq_set_irq_wake);
 732 
 733 /*
 734  * Internal function that tells the architecture code whether a
 735  * particular irq has been exclusively allocated or is available
 736  * for driver use.
 737  */
 738 int can_request_irq(unsigned int irq, unsigned long irqflags)
 739 {
 740         unsigned long flags;
 741         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 742         int canrequest = 0;
 743 
 744         if (!desc)
 745                 return 0;
 746 
 747         if (irq_settings_can_request(desc)) {
 748                 if (!desc->action ||
 749                     irqflags & desc->action->flags & IRQF_SHARED)
 750                         canrequest = 1;
 751         }
 752         irq_put_desc_unlock(desc, flags);
 753         return canrequest;
 754 }
 755 
 756 int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
 757 {
 758         struct irq_chip *chip = desc->irq_data.chip;
 759         int ret, unmask = 0;
 760 
 761         if (!chip || !chip->irq_set_type) {
 762                 /*
 763                  * IRQF_TRIGGER_* but the PIC does not support multiple
 764                  * flow-types?
 765                  */
 766                 pr_debug("No set_type function for IRQ %d (%s)\n",
 767                          irq_desc_get_irq(desc),
 768                          chip ? (chip->name ? : "unknown") : "unknown");
 769                 return 0;
 770         }
 771 
 772         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 773                 if (!irqd_irq_masked(&desc->irq_data))
 774                         mask_irq(desc);
 775                 if (!irqd_irq_disabled(&desc->irq_data))
 776                         unmask = 1;
 777         }
 778 
 779         /* Mask all flags except trigger mode */
 780         flags &= IRQ_TYPE_SENSE_MASK;
 781         ret = chip->irq_set_type(&desc->irq_data, flags);
 782 
 783         switch (ret) {
 784         case IRQ_SET_MASK_OK:
 785         case IRQ_SET_MASK_OK_DONE:
 786                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 787                 irqd_set(&desc->irq_data, flags);
 788                 /* fall through */
 789 
 790         case IRQ_SET_MASK_OK_NOCOPY:
 791                 flags = irqd_get_trigger_type(&desc->irq_data);
 792                 irq_settings_set_trigger_mask(desc, flags);
 793                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
 794                 irq_settings_clr_level(desc);
 795                 if (flags & IRQ_TYPE_LEVEL_MASK) {
 796                         irq_settings_set_level(desc);
 797                         irqd_set(&desc->irq_data, IRQD_LEVEL);
 798                 }
 799 
 800                 ret = 0;
 801                 break;
 802         default:
 803                 pr_err("Setting trigger mode %lu for irq %u failed (%pS)\n",
 804                        flags, irq_desc_get_irq(desc), chip->irq_set_type);
 805         }
 806         if (unmask)
 807                 unmask_irq(desc);
 808         return ret;
 809 }
 810 
 811 #ifdef CONFIG_HARDIRQS_SW_RESEND
 812 int irq_set_parent(int irq, int parent_irq)
 813 {
 814         unsigned long flags;
 815         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 816 
 817         if (!desc)
 818                 return -EINVAL;
 819 
 820         desc->parent_irq = parent_irq;
 821 
 822         irq_put_desc_unlock(desc, flags);
 823         return 0;
 824 }
 825 EXPORT_SYMBOL_GPL(irq_set_parent);
 826 #endif
 827 
 828 /*
 829  * Default primary interrupt handler for threaded interrupts. Is
 830  * assigned as primary handler when request_threaded_irq is called
 831  * with handler == NULL. Useful for oneshot interrupts.
 832  */
 833 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 834 {
 835         return IRQ_WAKE_THREAD;
 836 }
 837 
 838 /*
 839  * Primary handler for nested threaded interrupts. Should never be
 840  * called.
 841  */
 842 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 843 {
 844         WARN(1, "Primary handler called for nested irq %d\n", irq);
 845         return IRQ_NONE;
 846 }
 847 
 848 static irqreturn_t irq_forced_secondary_handler(int irq, void *dev_id)
 849 {
 850         WARN(1, "Secondary action handler called for irq %d\n", irq);
 851         return IRQ_NONE;
 852 }
 853 
 854 static int irq_wait_for_interrupt(struct irqaction *action)
 855 {
 856         for (;;) {
 857                 set_current_state(TASK_INTERRUPTIBLE);
 858 
 859                 if (kthread_should_stop()) {
 860                         /* may need to run one last time */
 861                         if (test_and_clear_bit(IRQTF_RUNTHREAD,
 862                                                &action->thread_flags)) {
 863                                 __set_current_state(TASK_RUNNING);
 864                                 return 0;
 865                         }
 866                         __set_current_state(TASK_RUNNING);
 867                         return -1;
 868                 }
 869 
 870                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
 871                                        &action->thread_flags)) {
 872                         __set_current_state(TASK_RUNNING);
 873                         return 0;
 874                 }
 875                 schedule();
 876         }
 877 }
 878 
 879 /*
 880  * Oneshot interrupts keep the irq line masked until the threaded
 881  * handler finished. unmask if the interrupt has not been disabled and
 882  * is marked MASKED.
 883  */
 884 static void irq_finalize_oneshot(struct irq_desc *desc,
 885                                  struct irqaction *action)
 886 {
 887         if (!(desc->istate & IRQS_ONESHOT) ||
 888             action->handler == irq_forced_secondary_handler)
 889                 return;
 890 again:
 891         chip_bus_lock(desc);
 892         raw_spin_lock_irq(&desc->lock);
 893 
 894         /*
 895          * Implausible though it may be we need to protect us against
 896          * the following scenario:
 897          *
 898          * The thread is faster done than the hard interrupt handler
 899          * on the other CPU. If we unmask the irq line then the
 900          * interrupt can come in again and masks the line, leaves due
 901          * to IRQS_INPROGRESS and the irq line is masked forever.
 902          *
 903          * This also serializes the state of shared oneshot handlers
 904          * versus "desc->threads_onehsot |= action->thread_mask;" in
 905          * irq_wake_thread(). See the comment there which explains the
 906          * serialization.
 907          */
 908         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 909                 raw_spin_unlock_irq(&desc->lock);
 910                 chip_bus_sync_unlock(desc);
 911                 cpu_relax();
 912                 goto again;
 913         }
 914 
 915         /*
 916          * Now check again, whether the thread should run. Otherwise
 917          * we would clear the threads_oneshot bit of this thread which
 918          * was just set.
 919          */
 920         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 921                 goto out_unlock;
 922 
 923         desc->threads_oneshot &= ~action->thread_mask;
 924 
 925         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 926             irqd_irq_masked(&desc->irq_data))
 927                 unmask_threaded_irq(desc);
 928 
 929 out_unlock:
 930         raw_spin_unlock_irq(&desc->lock);
 931         chip_bus_sync_unlock(desc);
 932 }
 933 
 934 #ifdef CONFIG_SMP
 935 /*
 936  * Check whether we need to change the affinity of the interrupt thread.
 937  */
 938 static void
 939 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 940 {
 941         cpumask_var_t mask;
 942         bool valid = true;
 943 
 944         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 945                 return;
 946 
 947         /*
 948          * In case we are out of memory we set IRQTF_AFFINITY again and
 949          * try again next time
 950          */
 951         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 952                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
 953                 return;
 954         }
 955 
 956         raw_spin_lock_irq(&desc->lock);
 957         /*
 958          * This code is triggered unconditionally. Check the affinity
 959          * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
 960          */
 961         if (cpumask_available(desc->irq_common_data.affinity)) {
 962                 const struct cpumask *m;
 963 
 964                 m = irq_data_get_effective_affinity_mask(&desc->irq_data);
 965                 cpumask_copy(mask, m);
 966         } else {
 967                 valid = false;
 968         }
 969         raw_spin_unlock_irq(&desc->lock);
 970 
 971         if (valid)
 972                 set_cpus_allowed_ptr(current, mask);
 973         free_cpumask_var(mask);
 974 }
 975 #else
 976 static inline void
 977 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 978 #endif
 979 
 980 /*
 981  * Interrupts which are not explicitly requested as threaded
 982  * interrupts rely on the implicit bh/preempt disable of the hard irq
 983  * context. So we need to disable bh here to avoid deadlocks and other
 984  * side effects.
 985  */
 986 static irqreturn_t
 987 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 988 {
 989         irqreturn_t ret;
 990 
 991         local_bh_disable();
 992         ret = action->thread_fn(action->irq, action->dev_id);
 993         if (ret == IRQ_HANDLED)
 994                 atomic_inc(&desc->threads_handled);
 995 
 996         irq_finalize_oneshot(desc, action);
 997         local_bh_enable();
 998         return ret;
 999 }
1000 
1001 /*
1002  * Interrupts explicitly requested as threaded interrupts want to be
1003  * preemtible - many of them need to sleep and wait for slow busses to
1004  * complete.
1005  */
1006 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
1007                 struct irqaction *action)
1008 {
1009         irqreturn_t ret;
1010 
1011         ret = action->thread_fn(action->irq, action->dev_id);
1012         if (ret == IRQ_HANDLED)
1013                 atomic_inc(&desc->threads_handled);
1014 
1015         irq_finalize_oneshot(desc, action);
1016         return ret;
1017 }
1018 
1019 static void wake_threads_waitq(struct irq_desc *desc)
1020 {
1021         if (atomic_dec_and_test(&desc->threads_active))
1022                 wake_up(&desc->wait_for_threads);
1023 }
1024 
1025 static void irq_thread_dtor(struct callback_head *unused)
1026 {
1027         struct task_struct *tsk = current;
1028         struct irq_desc *desc;
1029         struct irqaction *action;
1030 
1031         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
1032                 return;
1033 
1034         action = kthread_data(tsk);
1035 
1036         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
1037                tsk->comm, tsk->pid, action->irq);
1038 
1039 
1040         desc = irq_to_desc(action->irq);
1041         /*
1042          * If IRQTF_RUNTHREAD is set, we need to decrement
1043          * desc->threads_active and wake possible waiters.
1044          */
1045         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
1046                 wake_threads_waitq(desc);
1047 
1048         /* Prevent a stale desc->threads_oneshot */
1049         irq_finalize_oneshot(desc, action);
1050 }
1051 
1052 static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action)
1053 {
1054         struct irqaction *secondary = action->secondary;
1055 
1056         if (WARN_ON_ONCE(!secondary))
1057                 return;
1058 
1059         raw_spin_lock_irq(&desc->lock);
1060         __irq_wake_thread(desc, secondary);
1061         raw_spin_unlock_irq(&desc->lock);
1062 }
1063 
1064 /*
1065  * Interrupt handler thread
1066  */
1067 static int irq_thread(void *data)
1068 {
1069         struct callback_head on_exit_work;
1070         struct irqaction *action = data;
1071         struct irq_desc *desc = irq_to_desc(action->irq);
1072         irqreturn_t (*handler_fn)(struct irq_desc *desc,
1073                         struct irqaction *action);
1074 
1075         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
1076                                         &action->thread_flags))
1077                 handler_fn = irq_forced_thread_fn;
1078         else
1079                 handler_fn = irq_thread_fn;
1080 
1081         init_task_work(&on_exit_work, irq_thread_dtor);
1082         task_work_add(current, &on_exit_work, false);
1083 
1084         irq_thread_check_affinity(desc, action);
1085 
1086         while (!irq_wait_for_interrupt(action)) {
1087                 irqreturn_t action_ret;
1088 
1089                 irq_thread_check_affinity(desc, action);
1090 
1091                 action_ret = handler_fn(desc, action);
1092                 if (action_ret == IRQ_WAKE_THREAD)
1093                         irq_wake_secondary(desc, action);
1094 
1095                 wake_threads_waitq(desc);
1096         }
1097 
1098         /*
1099          * This is the regular exit path. __free_irq() is stopping the
1100          * thread via kthread_stop() after calling
1101          * synchronize_hardirq(). So neither IRQTF_RUNTHREAD nor the
1102          * oneshot mask bit can be set.
1103          */
1104         task_work_cancel(current, irq_thread_dtor);
1105         return 0;
1106 }
1107 
1108 /**
1109  *      irq_wake_thread - wake the irq thread for the action identified by dev_id
1110  *      @irq:           Interrupt line
1111  *      @dev_id:        Device identity for which the thread should be woken
1112  *
1113  */
1114 void irq_wake_thread(unsigned int irq, void *dev_id)
1115 {
1116         struct irq_desc *desc = irq_to_desc(irq);
1117         struct irqaction *action;
1118         unsigned long flags;
1119 
1120         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1121                 return;
1122 
1123         raw_spin_lock_irqsave(&desc->lock, flags);
1124         for_each_action_of_desc(desc, action) {
1125                 if (action->dev_id == dev_id) {
1126                         if (action->thread)
1127                                 __irq_wake_thread(desc, action);
1128                         break;
1129                 }
1130         }
1131         raw_spin_unlock_irqrestore(&desc->lock, flags);
1132 }
1133 EXPORT_SYMBOL_GPL(irq_wake_thread);
1134 
1135 static int irq_setup_forced_threading(struct irqaction *new)
1136 {
1137         if (!force_irqthreads)
1138                 return 0;
1139         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
1140                 return 0;
1141 
1142         /*
1143          * No further action required for interrupts which are requested as
1144          * threaded interrupts already
1145          */
1146         if (new->handler == irq_default_primary_handler)
1147                 return 0;
1148 
1149         new->flags |= IRQF_ONESHOT;
1150 
1151         /*
1152          * Handle the case where we have a real primary handler and a
1153          * thread handler. We force thread them as well by creating a
1154          * secondary action.
1155          */
1156         if (new->handler && new->thread_fn) {
1157                 /* Allocate the secondary action */
1158                 new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1159                 if (!new->secondary)
1160                         return -ENOMEM;
1161                 new->secondary->handler = irq_forced_secondary_handler;
1162                 new->secondary->thread_fn = new->thread_fn;
1163                 new->secondary->dev_id = new->dev_id;
1164                 new->secondary->irq = new->irq;
1165                 new->secondary->name = new->name;
1166         }
1167         /* Deal with the primary handler */
1168         set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
1169         new->thread_fn = new->handler;
1170         new->handler = irq_default_primary_handler;
1171         return 0;
1172 }
1173 
1174 static int irq_request_resources(struct irq_desc *desc)
1175 {
1176         struct irq_data *d = &desc->irq_data;
1177         struct irq_chip *c = d->chip;
1178 
1179         return c->irq_request_resources ? c->irq_request_resources(d) : 0;
1180 }
1181 
1182 static void irq_release_resources(struct irq_desc *desc)
1183 {
1184         struct irq_data *d = &desc->irq_data;
1185         struct irq_chip *c = d->chip;
1186 
1187         if (c->irq_release_resources)
1188                 c->irq_release_resources(d);
1189 }
1190 
1191 static bool irq_supports_nmi(struct irq_desc *desc)
1192 {
1193         struct irq_data *d = irq_desc_get_irq_data(desc);
1194 
1195 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
1196         /* Only IRQs directly managed by the root irqchip can be set as NMI */
1197         if (d->parent_data)
1198                 return false;
1199 #endif
1200         /* Don't support NMIs for chips behind a slow bus */
1201         if (d->chip->irq_bus_lock || d->chip->irq_bus_sync_unlock)
1202                 return false;
1203 
1204         return d->chip->flags & IRQCHIP_SUPPORTS_NMI;
1205 }
1206 
1207 static int irq_nmi_setup(struct irq_desc *desc)
1208 {
1209         struct irq_data *d = irq_desc_get_irq_data(desc);
1210         struct irq_chip *c = d->chip;
1211 
1212         return c->irq_nmi_setup ? c->irq_nmi_setup(d) : -EINVAL;
1213 }
1214 
1215 static void irq_nmi_teardown(struct irq_desc *desc)
1216 {
1217         struct irq_data *d = irq_desc_get_irq_data(desc);
1218         struct irq_chip *c = d->chip;
1219 
1220         if (c->irq_nmi_teardown)
1221                 c->irq_nmi_teardown(d);
1222 }
1223 
1224 static int
1225 setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
1226 {
1227         struct task_struct *t;
1228         struct sched_param param = {
1229                 .sched_priority = MAX_USER_RT_PRIO/2,
1230         };
1231 
1232         if (!secondary) {
1233                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1234                                    new->name);
1235         } else {
1236                 t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq,
1237                                    new->name);
1238                 param.sched_priority -= 1;
1239         }
1240 
1241         if (IS_ERR(t))
1242                 return PTR_ERR(t);
1243 
1244         sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
1245 
1246         /*
1247          * We keep the reference to the task struct even if
1248          * the thread dies to avoid that the interrupt code
1249          * references an already freed task_struct.
1250          */
1251         new->thread = get_task_struct(t);
1252         /*
1253          * Tell the thread to set its affinity. This is
1254          * important for shared interrupt handlers as we do
1255          * not invoke setup_affinity() for the secondary
1256          * handlers as everything is already set up. Even for
1257          * interrupts marked with IRQF_NO_BALANCE this is
1258          * correct as we want the thread to move to the cpu(s)
1259          * on which the requesting code placed the interrupt.
1260          */
1261         set_bit(IRQTF_AFFINITY, &new->thread_flags);
1262         return 0;
1263 }
1264 
1265 /*
1266  * Internal function to register an irqaction - typically used to
1267  * allocate special interrupts that are part of the architecture.
1268  *
1269  * Locking rules:
1270  *
1271  * desc->request_mutex  Provides serialization against a concurrent free_irq()
1272  *   chip_bus_lock      Provides serialization for slow bus operations
1273  *     desc->lock       Provides serialization against hard interrupts
1274  *
1275  * chip_bus_lock and desc->lock are sufficient for all other management and
1276  * interrupt related functions. desc->request_mutex solely serializes
1277  * request/free_irq().
1278  */
1279 static int
1280 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
1281 {
1282         struct irqaction *old, **old_ptr;
1283         unsigned long flags, thread_mask = 0;
1284         int ret, nested, shared = 0;
1285 
1286         if (!desc)
1287                 return -EINVAL;
1288 
1289         if (desc->irq_data.chip == &no_irq_chip)
1290                 return -ENOSYS;
1291         if (!try_module_get(desc->owner))
1292                 return -ENODEV;
1293 
1294         new->irq = irq;
1295 
1296         /*
1297          * If the trigger type is not specified by the caller,
1298          * then use the default for this interrupt.
1299          */
1300         if (!(new->flags & IRQF_TRIGGER_MASK))
1301                 new->flags |= irqd_get_trigger_type(&desc->irq_data);
1302 
1303         /*
1304          * Check whether the interrupt nests into another interrupt
1305          * thread.
1306          */
1307         nested = irq_settings_is_nested_thread(desc);
1308         if (nested) {
1309                 if (!new->thread_fn) {
1310                         ret = -EINVAL;
1311                         goto out_mput;
1312                 }
1313                 /*
1314                  * Replace the primary handler which was provided from
1315                  * the driver for non nested interrupt handling by the
1316                  * dummy function which warns when called.
1317                  */
1318                 new->handler = irq_nested_primary_handler;
1319         } else {
1320                 if (irq_settings_can_thread(desc)) {
1321                         ret = irq_setup_forced_threading(new);
1322                         if (ret)
1323                                 goto out_mput;
1324                 }
1325         }
1326 
1327         /*
1328          * Create a handler thread when a thread function is supplied
1329          * and the interrupt does not nest into another interrupt
1330          * thread.
1331          */
1332         if (new->thread_fn && !nested) {
1333                 ret = setup_irq_thread(new, irq, false);
1334                 if (ret)
1335                         goto out_mput;
1336                 if (new->secondary) {
1337                         ret = setup_irq_thread(new->secondary, irq, true);
1338                         if (ret)
1339                                 goto out_thread;
1340                 }
1341         }
1342 
1343         /*
1344          * Drivers are often written to work w/o knowledge about the
1345          * underlying irq chip implementation, so a request for a
1346          * threaded irq without a primary hard irq context handler
1347          * requires the ONESHOT flag to be set. Some irq chips like
1348          * MSI based interrupts are per se one shot safe. Check the
1349          * chip flags, so we can avoid the unmask dance at the end of
1350          * the threaded handler for those.
1351          */
1352         if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1353                 new->flags &= ~IRQF_ONESHOT;
1354 
1355         /*
1356          * Protects against a concurrent __free_irq() call which might wait
1357          * for synchronize_hardirq() to complete without holding the optional
1358          * chip bus lock and desc->lock. Also protects against handing out
1359          * a recycled oneshot thread_mask bit while it's still in use by
1360          * its previous owner.
1361          */
1362         mutex_lock(&desc->request_mutex);
1363 
1364         /*
1365          * Acquire bus lock as the irq_request_resources() callback below
1366          * might rely on the serialization or the magic power management
1367          * functions which are abusing the irq_bus_lock() callback,
1368          */
1369         chip_bus_lock(desc);
1370 
1371         /* First installed action requests resources. */
1372         if (!desc->action) {
1373                 ret = irq_request_resources(desc);
1374                 if (ret) {
1375                         pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1376                                new->name, irq, desc->irq_data.chip->name);
1377                         goto out_bus_unlock;
1378                 }
1379         }
1380 
1381         /*
1382          * The following block of code has to be executed atomically
1383          * protected against a concurrent interrupt and any of the other
1384          * management calls which are not serialized via
1385          * desc->request_mutex or the optional bus lock.
1386          */
1387         raw_spin_lock_irqsave(&desc->lock, flags);
1388         old_ptr = &desc->action;
1389         old = *old_ptr;
1390         if (old) {
1391                 /*
1392                  * Can't share interrupts unless both agree to and are
1393                  * the same type (level, edge, polarity). So both flag
1394                  * fields must have IRQF_SHARED set and the bits which
1395                  * set the trigger type must match. Also all must
1396                  * agree on ONESHOT.
1397                  * Interrupt lines used for NMIs cannot be shared.
1398                  */
1399                 unsigned int oldtype;
1400 
1401                 if (desc->istate & IRQS_NMI) {
1402                         pr_err("Invalid attempt to share NMI for %s (irq %d) on irqchip %s.\n",
1403                                 new->name, irq, desc->irq_data.chip->name);
1404                         ret = -EINVAL;
1405                         goto out_unlock;
1406                 }
1407 
1408                 /*
1409                  * If nobody did set the configuration before, inherit
1410                  * the one provided by the requester.
1411                  */
1412                 if (irqd_trigger_type_was_set(&desc->irq_data)) {
1413                         oldtype = irqd_get_trigger_type(&desc->irq_data);
1414                 } else {
1415                         oldtype = new->flags & IRQF_TRIGGER_MASK;
1416                         irqd_set_trigger_type(&desc->irq_data, oldtype);
1417                 }
1418 
1419                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1420                     (oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
1421                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
1422                         goto mismatch;
1423 
1424                 /* All handlers must agree on per-cpuness */
1425                 if ((old->flags & IRQF_PERCPU) !=
1426                     (new->flags & IRQF_PERCPU))
1427                         goto mismatch;
1428 
1429                 /* add new interrupt at end of irq queue */
1430                 do {
1431                         /*
1432                          * Or all existing action->thread_mask bits,
1433                          * so we can find the next zero bit for this
1434                          * new action.
1435                          */
1436                         thread_mask |= old->thread_mask;
1437                         old_ptr = &old->next;
1438                         old = *old_ptr;
1439                 } while (old);
1440                 shared = 1;
1441         }
1442 
1443         /*
1444          * Setup the thread mask for this irqaction for ONESHOT. For
1445          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1446          * conditional in irq_wake_thread().
1447          */
1448         if (new->flags & IRQF_ONESHOT) {
1449                 /*
1450                  * Unlikely to have 32 resp 64 irqs sharing one line,
1451                  * but who knows.
1452                  */
1453                 if (thread_mask == ~0UL) {
1454                         ret = -EBUSY;
1455                         goto out_unlock;
1456                 }
1457                 /*
1458                  * The thread_mask for the action is or'ed to
1459                  * desc->thread_active to indicate that the
1460                  * IRQF_ONESHOT thread handler has been woken, but not
1461                  * yet finished. The bit is cleared when a thread
1462                  * completes. When all threads of a shared interrupt
1463                  * line have completed desc->threads_active becomes
1464                  * zero and the interrupt line is unmasked. See
1465                  * handle.c:irq_wake_thread() for further information.
1466                  *
1467                  * If no thread is woken by primary (hard irq context)
1468                  * interrupt handlers, then desc->threads_active is
1469                  * also checked for zero to unmask the irq line in the
1470                  * affected hard irq flow handlers
1471                  * (handle_[fasteoi|level]_irq).
1472                  *
1473                  * The new action gets the first zero bit of
1474                  * thread_mask assigned. See the loop above which or's
1475                  * all existing action->thread_mask bits.
1476                  */
1477                 new->thread_mask = 1UL << ffz(thread_mask);
1478 
1479         } else if (new->handler == irq_default_primary_handler &&
1480                    !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1481                 /*
1482                  * The interrupt was requested with handler = NULL, so
1483                  * we use the default primary handler for it. But it
1484                  * does not have the oneshot flag set. In combination
1485                  * with level interrupts this is deadly, because the
1486                  * default primary handler just wakes the thread, then
1487                  * the irq lines is reenabled, but the device still
1488                  * has the level irq asserted. Rinse and repeat....
1489                  *
1490                  * While this works for edge type interrupts, we play
1491                  * it safe and reject unconditionally because we can't
1492                  * say for sure which type this interrupt really
1493                  * has. The type flags are unreliable as the
1494                  * underlying chip implementation can override them.
1495                  */
1496                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1497                        irq);
1498                 ret = -EINVAL;
1499                 goto out_unlock;
1500         }
1501 
1502         if (!shared) {
1503                 init_waitqueue_head(&desc->wait_for_threads);
1504 
1505                 /* Setup the type (level, edge polarity) if configured: */
1506                 if (new->flags & IRQF_TRIGGER_MASK) {
1507                         ret = __irq_set_trigger(desc,
1508                                                 new->flags & IRQF_TRIGGER_MASK);
1509 
1510                         if (ret)
1511                                 goto out_unlock;
1512                 }
1513 
1514                 /*
1515                  * Activate the interrupt. That activation must happen
1516                  * independently of IRQ_NOAUTOEN. request_irq() can fail
1517                  * and the callers are supposed to handle
1518                  * that. enable_irq() of an interrupt requested with
1519                  * IRQ_NOAUTOEN is not supposed to fail. The activation
1520                  * keeps it in shutdown mode, it merily associates
1521                  * resources if necessary and if that's not possible it
1522                  * fails. Interrupts which are in managed shutdown mode
1523                  * will simply ignore that activation request.
1524                  */
1525                 ret = irq_activate(desc);
1526                 if (ret)
1527                         goto out_unlock;
1528 
1529                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1530                                   IRQS_ONESHOT | IRQS_WAITING);
1531                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1532 
1533                 if (new->flags & IRQF_PERCPU) {
1534                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1535                         irq_settings_set_per_cpu(desc);
1536                 }
1537 
1538                 if (new->flags & IRQF_ONESHOT)
1539                         desc->istate |= IRQS_ONESHOT;
1540 
1541                 /* Exclude IRQ from balancing if requested */
1542                 if (new->flags & IRQF_NOBALANCING) {
1543                         irq_settings_set_no_balancing(desc);
1544                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1545                 }
1546 
1547                 if (irq_settings_can_autoenable(desc)) {
1548                         irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
1549                 } else {
1550                         /*
1551                          * Shared interrupts do not go well with disabling
1552                          * auto enable. The sharing interrupt might request
1553                          * it while it's still disabled and then wait for
1554                          * interrupts forever.
1555                          */
1556                         WARN_ON_ONCE(new->flags & IRQF_SHARED);
1557                         /* Undo nested disables: */
1558                         desc->depth = 1;
1559                 }
1560 
1561         } else if (new->flags & IRQF_TRIGGER_MASK) {
1562                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1563                 unsigned int omsk = irqd_get_trigger_type(&desc->irq_data);
1564 
1565                 if (nmsk != omsk)
1566                         /* hope the handler works with current  trigger mode */
1567                         pr_warn("irq %d uses trigger mode %u; requested %u\n",
1568                                 irq, omsk, nmsk);
1569         }
1570 
1571         *old_ptr = new;
1572 
1573         irq_pm_install_action(desc, new);
1574 
1575         /* Reset broken irq detection when installing new handler */
1576         desc->irq_count = 0;
1577         desc->irqs_unhandled = 0;
1578 
1579         /*
1580          * Check whether we disabled the irq via the spurious handler
1581          * before. Reenable it and give it another chance.
1582          */
1583         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1584                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1585                 __enable_irq(desc);
1586         }
1587 
1588         raw_spin_unlock_irqrestore(&desc->lock, flags);
1589         chip_bus_sync_unlock(desc);
1590         mutex_unlock(&desc->request_mutex);
1591 
1592         irq_setup_timings(desc, new);
1593 
1594         /*
1595          * Strictly no need to wake it up, but hung_task complains
1596          * when no hard interrupt wakes the thread up.
1597          */
1598         if (new->thread)
1599                 wake_up_process(new->thread);
1600         if (new->secondary)
1601                 wake_up_process(new->secondary->thread);
1602 
1603         register_irq_proc(irq, desc);
1604         new->dir = NULL;
1605         register_handler_proc(irq, new);
1606         return 0;
1607 
1608 mismatch:
1609         if (!(new->flags & IRQF_PROBE_SHARED)) {
1610                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1611                        irq, new->flags, new->name, old->flags, old->name);
1612 #ifdef CONFIG_DEBUG_SHIRQ
1613                 dump_stack();
1614 #endif
1615         }
1616         ret = -EBUSY;
1617 
1618 out_unlock:
1619         raw_spin_unlock_irqrestore(&desc->lock, flags);
1620 
1621         if (!desc->action)
1622                 irq_release_resources(desc);
1623 out_bus_unlock:
1624         chip_bus_sync_unlock(desc);
1625         mutex_unlock(&desc->request_mutex);
1626 
1627 out_thread:
1628         if (new->thread) {
1629                 struct task_struct *t = new->thread;
1630 
1631                 new->thread = NULL;
1632                 kthread_stop(t);
1633                 put_task_struct(t);
1634         }
1635         if (new->secondary && new->secondary->thread) {
1636                 struct task_struct *t = new->secondary->thread;
1637 
1638                 new->secondary->thread = NULL;
1639                 kthread_stop(t);
1640                 put_task_struct(t);
1641         }
1642 out_mput:
1643         module_put(desc->owner);
1644         return ret;
1645 }
1646 
1647 /**
1648  *      setup_irq - setup an interrupt
1649  *      @irq: Interrupt line to setup
1650  *      @act: irqaction for the interrupt
1651  *
1652  * Used to statically setup interrupts in the early boot process.
1653  */
1654 int setup_irq(unsigned int irq, struct irqaction *act)
1655 {
1656         int retval;
1657         struct irq_desc *desc = irq_to_desc(irq);
1658 
1659         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1660                 return -EINVAL;
1661 
1662         retval = irq_chip_pm_get(&desc->irq_data);
1663         if (retval < 0)
1664                 return retval;
1665 
1666         retval = __setup_irq(irq, desc, act);
1667 
1668         if (retval)
1669                 irq_chip_pm_put(&desc->irq_data);
1670 
1671         return retval;
1672 }
1673 EXPORT_SYMBOL_GPL(setup_irq);
1674 
1675 /*
1676  * Internal function to unregister an irqaction - used to free
1677  * regular and special interrupts that are part of the architecture.
1678  */
1679 static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
1680 {
1681         unsigned irq = desc->irq_data.irq;
1682         struct irqaction *action, **action_ptr;
1683         unsigned long flags;
1684 
1685         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1686 
1687         mutex_lock(&desc->request_mutex);
1688         chip_bus_lock(desc);
1689         raw_spin_lock_irqsave(&desc->lock, flags);
1690 
1691         /*
1692          * There can be multiple actions per IRQ descriptor, find the right
1693          * one based on the dev_id:
1694          */
1695         action_ptr = &desc->action;
1696         for (;;) {
1697                 action = *action_ptr;
1698 
1699                 if (!action) {
1700                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1701                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1702                         chip_bus_sync_unlock(desc);
1703                         mutex_unlock(&desc->request_mutex);
1704                         return NULL;
1705                 }
1706 
1707                 if (action->dev_id == dev_id)
1708                         break;
1709                 action_ptr = &action->next;
1710         }
1711 
1712         /* Found it - now remove it from the list of entries: */
1713         *action_ptr = action->next;
1714 
1715         irq_pm_remove_action(desc, action);
1716 
1717         /* If this was the last handler, shut down the IRQ line: */
1718         if (!desc->action) {
1719                 irq_settings_clr_disable_unlazy(desc);
1720                 /* Only shutdown. Deactivate after synchronize_hardirq() */
1721                 irq_shutdown(desc);
1722         }
1723 
1724 #ifdef CONFIG_SMP
1725         /* make sure affinity_hint is cleaned up */
1726         if (WARN_ON_ONCE(desc->affinity_hint))
1727                 desc->affinity_hint = NULL;
1728 #endif
1729 
1730         raw_spin_unlock_irqrestore(&desc->lock, flags);
1731         /*
1732          * Drop bus_lock here so the changes which were done in the chip
1733          * callbacks above are synced out to the irq chips which hang
1734          * behind a slow bus (I2C, SPI) before calling synchronize_hardirq().
1735          *
1736          * Aside of that the bus_lock can also be taken from the threaded
1737          * handler in irq_finalize_oneshot() which results in a deadlock
1738          * because kthread_stop() would wait forever for the thread to
1739          * complete, which is blocked on the bus lock.
1740          *
1741          * The still held desc->request_mutex() protects against a
1742          * concurrent request_irq() of this irq so the release of resources
1743          * and timing data is properly serialized.
1744          */
1745         chip_bus_sync_unlock(desc);
1746 
1747         unregister_handler_proc(irq, action);
1748 
1749         /*
1750          * Make sure it's not being used on another CPU and if the chip
1751          * supports it also make sure that there is no (not yet serviced)
1752          * interrupt in flight at the hardware level.
1753          */
1754         __synchronize_hardirq(desc, true);
1755 
1756 #ifdef CONFIG_DEBUG_SHIRQ
1757         /*
1758          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1759          * event to happen even now it's being freed, so let's make sure that
1760          * is so by doing an extra call to the handler ....
1761          *
1762          * ( We do this after actually deregistering it, to make sure that a
1763          *   'real' IRQ doesn't run in parallel with our fake. )
1764          */
1765         if (action->flags & IRQF_SHARED) {
1766                 local_irq_save(flags);
1767                 action->handler(irq, dev_id);
1768                 local_irq_restore(flags);
1769         }
1770 #endif
1771 
1772         /*
1773          * The action has already been removed above, but the thread writes
1774          * its oneshot mask bit when it completes. Though request_mutex is
1775          * held across this which prevents __setup_irq() from handing out
1776          * the same bit to a newly requested action.
1777          */
1778         if (action->thread) {
1779                 kthread_stop(action->thread);
1780                 put_task_struct(action->thread);
1781                 if (action->secondary && action->secondary->thread) {
1782                         kthread_stop(action->secondary->thread);
1783                         put_task_struct(action->secondary->thread);
1784                 }
1785         }
1786 
1787         /* Last action releases resources */
1788         if (!desc->action) {
1789                 /*
1790                  * Reaquire bus lock as irq_release_resources() might
1791                  * require it to deallocate resources over the slow bus.
1792                  */
1793                 chip_bus_lock(desc);
1794                 /*
1795                  * There is no interrupt on the fly anymore. Deactivate it
1796                  * completely.
1797                  */
1798                 raw_spin_lock_irqsave(&desc->lock, flags);
1799                 irq_domain_deactivate_irq(&desc->irq_data);
1800                 raw_spin_unlock_irqrestore(&desc->lock, flags);
1801 
1802                 irq_release_resources(desc);
1803                 chip_bus_sync_unlock(desc);
1804                 irq_remove_timings(desc);
1805         }
1806 
1807         mutex_unlock(&desc->request_mutex);
1808 
1809         irq_chip_pm_put(&desc->irq_data);
1810         module_put(desc->owner);
1811         kfree(action->secondary);
1812         return action;
1813 }
1814 
1815 /**
1816  *      remove_irq - free an interrupt
1817  *      @irq: Interrupt line to free
1818  *      @act: irqaction for the interrupt
1819  *
1820  * Used to remove interrupts statically setup by the early boot process.
1821  */
1822 void remove_irq(unsigned int irq, struct irqaction *act)
1823 {
1824         struct irq_desc *desc = irq_to_desc(irq);
1825 
1826         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1827                 __free_irq(desc, act->dev_id);
1828 }
1829 EXPORT_SYMBOL_GPL(remove_irq);
1830 
1831 /**
1832  *      free_irq - free an interrupt allocated with request_irq
1833  *      @irq: Interrupt line to free
1834  *      @dev_id: Device identity to free
1835  *
1836  *      Remove an interrupt handler. The handler is removed and if the
1837  *      interrupt line is no longer in use by any driver it is disabled.
1838  *      On a shared IRQ the caller must ensure the interrupt is disabled
1839  *      on the card it drives before calling this function. The function
1840  *      does not return until any executing interrupts for this IRQ
1841  *      have completed.
1842  *
1843  *      This function must not be called from interrupt context.
1844  *
1845  *      Returns the devname argument passed to request_irq.
1846  */
1847 const void *free_irq(unsigned int irq, void *dev_id)
1848 {
1849         struct irq_desc *desc = irq_to_desc(irq);
1850         struct irqaction *action;
1851         const char *devname;
1852 
1853         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1854                 return NULL;
1855 
1856 #ifdef CONFIG_SMP
1857         if (WARN_ON(desc->affinity_notify))
1858                 desc->affinity_notify = NULL;
1859 #endif
1860 
1861         action = __free_irq(desc, dev_id);
1862 
1863         if (!action)
1864                 return NULL;
1865 
1866         devname = action->name;
1867         kfree(action);
1868         return devname;
1869 }
1870 EXPORT_SYMBOL(free_irq);
1871 
1872 /* This function must be called with desc->lock held */
1873 static const void *__cleanup_nmi(unsigned int irq, struct irq_desc *desc)
1874 {
1875         const char *devname = NULL;
1876 
1877         desc->istate &= ~IRQS_NMI;
1878 
1879         if (!WARN_ON(desc->action == NULL)) {
1880                 irq_pm_remove_action(desc, desc->action);
1881                 devname = desc->action->name;
1882                 unregister_handler_proc(irq, desc->action);
1883 
1884                 kfree(desc->action);
1885                 desc->action = NULL;
1886         }
1887 
1888         irq_settings_clr_disable_unlazy(desc);
1889         irq_shutdown_and_deactivate(desc);
1890 
1891         irq_release_resources(desc);
1892 
1893         irq_chip_pm_put(&desc->irq_data);
1894         module_put(desc->owner);
1895 
1896         return devname;
1897 }
1898 
1899 const void *free_nmi(unsigned int irq, void *dev_id)
1900 {
1901         struct irq_desc *desc = irq_to_desc(irq);
1902         unsigned long flags;
1903         const void *devname;
1904 
1905         if (!desc || WARN_ON(!(desc->istate & IRQS_NMI)))
1906                 return NULL;
1907 
1908         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1909                 return NULL;
1910 
1911         /* NMI still enabled */
1912         if (WARN_ON(desc->depth == 0))
1913                 disable_nmi_nosync(irq);
1914 
1915         raw_spin_lock_irqsave(&desc->lock, flags);
1916 
1917         irq_nmi_teardown(desc);
1918         devname = __cleanup_nmi(irq, desc);
1919 
1920         raw_spin_unlock_irqrestore(&desc->lock, flags);
1921 
1922         return devname;
1923 }
1924 
1925 /**
1926  *      request_threaded_irq - allocate an interrupt line
1927  *      @irq: Interrupt line to allocate
1928  *      @handler: Function to be called when the IRQ occurs.
1929  *                Primary handler for threaded interrupts
1930  *                If NULL and thread_fn != NULL the default
1931  *                primary handler is installed
1932  *      @thread_fn: Function called from the irq handler thread
1933  *                  If NULL, no irq thread is created
1934  *      @irqflags: Interrupt type flags
1935  *      @devname: An ascii name for the claiming device
1936  *      @dev_id: A cookie passed back to the handler function
1937  *
1938  *      This call allocates interrupt resources and enables the
1939  *      interrupt line and IRQ handling. From the point this
1940  *      call is made your handler function may be invoked. Since
1941  *      your handler function must clear any interrupt the board
1942  *      raises, you must take care both to initialise your hardware
1943  *      and to set up the interrupt handler in the right order.
1944  *
1945  *      If you want to set up a threaded irq handler for your device
1946  *      then you need to supply @handler and @thread_fn. @handler is
1947  *      still called in hard interrupt context and has to check
1948  *      whether the interrupt originates from the device. If yes it
1949  *      needs to disable the interrupt on the device and return
1950  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1951  *      @thread_fn. This split handler design is necessary to support
1952  *      shared interrupts.
1953  *
1954  *      Dev_id must be globally unique. Normally the address of the
1955  *      device data structure is used as the cookie. Since the handler
1956  *      receives this value it makes sense to use it.
1957  *
1958  *      If your interrupt is shared you must pass a non NULL dev_id
1959  *      as this is required when freeing the interrupt.
1960  *
1961  *      Flags:
1962  *
1963  *      IRQF_SHARED             Interrupt is shared
1964  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1965  *
1966  */
1967 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1968                          irq_handler_t thread_fn, unsigned long irqflags,
1969                          const char *devname, void *dev_id)
1970 {
1971         struct irqaction *action;
1972         struct irq_desc *desc;
1973         int retval;
1974 
1975         if (irq == IRQ_NOTCONNECTED)
1976                 return -ENOTCONN;
1977 
1978         /*
1979          * Sanity-check: shared interrupts must pass in a real dev-ID,
1980          * otherwise we'll have trouble later trying to figure out
1981          * which interrupt is which (messes up the interrupt freeing
1982          * logic etc).
1983          *
1984          * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
1985          * it cannot be set along with IRQF_NO_SUSPEND.
1986          */
1987         if (((irqflags & IRQF_SHARED) && !dev_id) ||
1988             (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
1989             ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
1990                 return -EINVAL;
1991 
1992         desc = irq_to_desc(irq);
1993         if (!desc)
1994                 return -EINVAL;
1995 
1996         if (!irq_settings_can_request(desc) ||
1997             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1998                 return -EINVAL;
1999 
2000         if (!handler) {
2001                 if (!thread_fn)
2002                         return -EINVAL;
2003                 handler = irq_default_primary_handler;
2004         }
2005 
2006         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2007         if (!action)
2008                 return -ENOMEM;
2009 
2010         action->handler = handler;
2011         action->thread_fn = thread_fn;
2012         action->flags = irqflags;
2013         action->name = devname;
2014         action->dev_id = dev_id;
2015 
2016         retval = irq_chip_pm_get(&desc->irq_data);
2017         if (retval < 0) {
2018                 kfree(action);
2019                 return retval;
2020         }
2021 
2022         retval = __setup_irq(irq, desc, action);
2023 
2024         if (retval) {
2025                 irq_chip_pm_put(&desc->irq_data);
2026                 kfree(action->secondary);
2027                 kfree(action);
2028         }
2029 
2030 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
2031         if (!retval && (irqflags & IRQF_SHARED)) {
2032                 /*
2033                  * It's a shared IRQ -- the driver ought to be prepared for it
2034                  * to happen immediately, so let's make sure....
2035                  * We disable the irq to make sure that a 'real' IRQ doesn't
2036                  * run in parallel with our fake.
2037                  */
2038                 unsigned long flags;
2039 
2040                 disable_irq(irq);
2041                 local_irq_save(flags);
2042 
2043                 handler(irq, dev_id);
2044 
2045                 local_irq_restore(flags);
2046                 enable_irq(irq);
2047         }
2048 #endif
2049         return retval;
2050 }
2051 EXPORT_SYMBOL(request_threaded_irq);
2052 
2053 /**
2054  *      request_any_context_irq - allocate an interrupt line
2055  *      @irq: Interrupt line to allocate
2056  *      @handler: Function to be called when the IRQ occurs.
2057  *                Threaded handler for threaded interrupts.
2058  *      @flags: Interrupt type flags
2059  *      @name: An ascii name for the claiming device
2060  *      @dev_id: A cookie passed back to the handler function
2061  *
2062  *      This call allocates interrupt resources and enables the
2063  *      interrupt line and IRQ handling. It selects either a
2064  *      hardirq or threaded handling method depending on the
2065  *      context.
2066  *
2067  *      On failure, it returns a negative value. On success,
2068  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
2069  */
2070 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
2071                             unsigned long flags, const char *name, void *dev_id)
2072 {
2073         struct irq_desc *desc;
2074         int ret;
2075 
2076         if (irq == IRQ_NOTCONNECTED)
2077                 return -ENOTCONN;
2078 
2079         desc = irq_to_desc(irq);
2080         if (!desc)
2081                 return -EINVAL;
2082 
2083         if (irq_settings_is_nested_thread(desc)) {
2084                 ret = request_threaded_irq(irq, NULL, handler,
2085                                            flags, name, dev_id);
2086                 return !ret ? IRQC_IS_NESTED : ret;
2087         }
2088 
2089         ret = request_irq(irq, handler, flags, name, dev_id);
2090         return !ret ? IRQC_IS_HARDIRQ : ret;
2091 }
2092 EXPORT_SYMBOL_GPL(request_any_context_irq);
2093 
2094 /**
2095  *      request_nmi - allocate an interrupt line for NMI delivery
2096  *      @irq: Interrupt line to allocate
2097  *      @handler: Function to be called when the IRQ occurs.
2098  *                Threaded handler for threaded interrupts.
2099  *      @irqflags: Interrupt type flags
2100  *      @name: An ascii name for the claiming device
2101  *      @dev_id: A cookie passed back to the handler function
2102  *
2103  *      This call allocates interrupt resources and enables the
2104  *      interrupt line and IRQ handling. It sets up the IRQ line
2105  *      to be handled as an NMI.
2106  *
2107  *      An interrupt line delivering NMIs cannot be shared and IRQ handling
2108  *      cannot be threaded.
2109  *
2110  *      Interrupt lines requested for NMI delivering must produce per cpu
2111  *      interrupts and have auto enabling setting disabled.
2112  *
2113  *      Dev_id must be globally unique. Normally the address of the
2114  *      device data structure is used as the cookie. Since the handler
2115  *      receives this value it makes sense to use it.
2116  *
2117  *      If the interrupt line cannot be used to deliver NMIs, function
2118  *      will fail and return a negative value.
2119  */
2120 int request_nmi(unsigned int irq, irq_handler_t handler,
2121                 unsigned long irqflags, const char *name, void *dev_id)
2122 {
2123         struct irqaction *action;
2124         struct irq_desc *desc;
2125         unsigned long flags;
2126         int retval;
2127 
2128         if (irq == IRQ_NOTCONNECTED)
2129                 return -ENOTCONN;
2130 
2131         /* NMI cannot be shared, used for Polling */
2132         if (irqflags & (IRQF_SHARED | IRQF_COND_SUSPEND | IRQF_IRQPOLL))
2133                 return -EINVAL;
2134 
2135         if (!(irqflags & IRQF_PERCPU))
2136                 return -EINVAL;
2137 
2138         if (!handler)
2139                 return -EINVAL;
2140 
2141         desc = irq_to_desc(irq);
2142 
2143         if (!desc || irq_settings_can_autoenable(desc) ||
2144             !irq_settings_can_request(desc) ||
2145             WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
2146             !irq_supports_nmi(desc))
2147                 return -EINVAL;
2148 
2149         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2150         if (!action)
2151                 return -ENOMEM;
2152 
2153         action->handler = handler;
2154         action->flags = irqflags | IRQF_NO_THREAD | IRQF_NOBALANCING;
2155         action->name = name;
2156         action->dev_id = dev_id;
2157 
2158         retval = irq_chip_pm_get(&desc->irq_data);
2159         if (retval < 0)
2160                 goto err_out;
2161 
2162         retval = __setup_irq(irq, desc, action);
2163         if (retval)
2164                 goto err_irq_setup;
2165 
2166         raw_spin_lock_irqsave(&desc->lock, flags);
2167 
2168         /* Setup NMI state */
2169         desc->istate |= IRQS_NMI;
2170         retval = irq_nmi_setup(desc);
2171         if (retval) {
2172                 __cleanup_nmi(irq, desc);
2173                 raw_spin_unlock_irqrestore(&desc->lock, flags);
2174                 return -EINVAL;
2175         }
2176 
2177         raw_spin_unlock_irqrestore(&desc->lock, flags);
2178 
2179         return 0;
2180 
2181 err_irq_setup:
2182         irq_chip_pm_put(&desc->irq_data);
2183 err_out:
2184         kfree(action);
2185 
2186         return retval;
2187 }
2188 
2189 void enable_percpu_irq(unsigned int irq, unsigned int type)
2190 {
2191         unsigned int cpu = smp_processor_id();
2192         unsigned long flags;
2193         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2194 
2195         if (!desc)
2196                 return;
2197 
2198         /*
2199          * If the trigger type is not specified by the caller, then
2200          * use the default for this interrupt.
2201          */
2202         type &= IRQ_TYPE_SENSE_MASK;
2203         if (type == IRQ_TYPE_NONE)
2204                 type = irqd_get_trigger_type(&desc->irq_data);
2205 
2206         if (type != IRQ_TYPE_NONE) {
2207                 int ret;
2208 
2209                 ret = __irq_set_trigger(desc, type);
2210 
2211                 if (ret) {
2212                         WARN(1, "failed to set type for IRQ%d\n", irq);
2213                         goto out;
2214                 }
2215         }
2216 
2217         irq_percpu_enable(desc, cpu);
2218 out:
2219         irq_put_desc_unlock(desc, flags);
2220 }
2221 EXPORT_SYMBOL_GPL(enable_percpu_irq);
2222 
2223 void enable_percpu_nmi(unsigned int irq, unsigned int type)
2224 {
2225         enable_percpu_irq(irq, type);
2226 }
2227 
2228 /**
2229  * irq_percpu_is_enabled - Check whether the per cpu irq is enabled
2230  * @irq:        Linux irq number to check for
2231  *
2232  * Must be called from a non migratable context. Returns the enable
2233  * state of a per cpu interrupt on the current cpu.
2234  */
2235 bool irq_percpu_is_enabled(unsigned int irq)
2236 {
2237         unsigned int cpu = smp_processor_id();
2238         struct irq_desc *desc;
2239         unsigned long flags;
2240         bool is_enabled;
2241 
2242         desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2243         if (!desc)
2244                 return false;
2245 
2246         is_enabled = cpumask_test_cpu(cpu, desc->percpu_enabled);
2247         irq_put_desc_unlock(desc, flags);
2248 
2249         return is_enabled;
2250 }
2251 EXPORT_SYMBOL_GPL(irq_percpu_is_enabled);
2252 
2253 void disable_percpu_irq(unsigned int irq)
2254 {
2255         unsigned int cpu = smp_processor_id();
2256         unsigned long flags;
2257         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2258 
2259         if (!desc)
2260                 return;
2261 
2262         irq_percpu_disable(desc, cpu);
2263         irq_put_desc_unlock(desc, flags);
2264 }
2265 EXPORT_SYMBOL_GPL(disable_percpu_irq);
2266 
2267 void disable_percpu_nmi(unsigned int irq)
2268 {
2269         disable_percpu_irq(irq);
2270 }
2271 
2272 /*
2273  * Internal function to unregister a percpu irqaction.
2274  */
2275 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
2276 {
2277         struct irq_desc *desc = irq_to_desc(irq);
2278         struct irqaction *action;
2279         unsigned long flags;
2280 
2281         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
2282 
2283         if (!desc)
2284                 return NULL;
2285 
2286         raw_spin_lock_irqsave(&desc->lock, flags);
2287 
2288         action = desc->action;
2289         if (!action || action->percpu_dev_id != dev_id) {
2290                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
2291                 goto bad;
2292         }
2293 
2294         if (!cpumask_empty(desc->percpu_enabled)) {
2295                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
2296                      irq, cpumask_first(desc->percpu_enabled));
2297                 goto bad;
2298         }
2299 
2300         /* Found it - now remove it from the list of entries: */
2301         desc->action = NULL;
2302 
2303         desc->istate &= ~IRQS_NMI;
2304 
2305         raw_spin_unlock_irqrestore(&desc->lock, flags);
2306 
2307         unregister_handler_proc(irq, action);
2308 
2309         irq_chip_pm_put(&desc->irq_data);
2310         module_put(desc->owner);
2311         return action;
2312 
2313 bad:
2314         raw_spin_unlock_irqrestore(&desc->lock, flags);
2315         return NULL;
2316 }
2317 
2318 /**
2319  *      remove_percpu_irq - free a per-cpu interrupt
2320  *      @irq: Interrupt line to free
2321  *      @act: irqaction for the interrupt
2322  *
2323  * Used to remove interrupts statically setup by the early boot process.
2324  */
2325 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
2326 {
2327         struct irq_desc *desc = irq_to_desc(irq);
2328 
2329         if (desc && irq_settings_is_per_cpu_devid(desc))
2330             __free_percpu_irq(irq, act->percpu_dev_id);
2331 }
2332 
2333 /**
2334  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
2335  *      @irq: Interrupt line to free
2336  *      @dev_id: Device identity to free
2337  *
2338  *      Remove a percpu interrupt handler. The handler is removed, but
2339  *      the interrupt line is not disabled. This must be done on each
2340  *      CPU before calling this function. The function does not return
2341  *      until any executing interrupts for this IRQ have completed.
2342  *
2343  *      This function must not be called from interrupt context.
2344  */
2345 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
2346 {
2347         struct irq_desc *desc = irq_to_desc(irq);
2348 
2349         if (!desc || !irq_settings_is_per_cpu_devid(desc))
2350                 return;
2351 
2352         chip_bus_lock(desc);
2353         kfree(__free_percpu_irq(irq, dev_id));
2354         chip_bus_sync_unlock(desc);
2355 }
2356 EXPORT_SYMBOL_GPL(free_percpu_irq);
2357 
2358 void free_percpu_nmi(unsigned int irq, void __percpu *dev_id)
2359 {
2360         struct irq_desc *desc = irq_to_desc(irq);
2361 
2362         if (!desc || !irq_settings_is_per_cpu_devid(desc))
2363                 return;
2364 
2365         if (WARN_ON(!(desc->istate & IRQS_NMI)))
2366                 return;
2367 
2368         kfree(__free_percpu_irq(irq, dev_id));
2369 }
2370 
2371 /**
2372  *      setup_percpu_irq - setup a per-cpu interrupt
2373  *      @irq: Interrupt line to setup
2374  *      @act: irqaction for the interrupt
2375  *
2376  * Used to statically setup per-cpu interrupts in the early boot process.
2377  */
2378 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
2379 {
2380         struct irq_desc *desc = irq_to_desc(irq);
2381         int retval;
2382 
2383         if (!desc || !irq_settings_is_per_cpu_devid(desc))
2384                 return -EINVAL;
2385 
2386         retval = irq_chip_pm_get(&desc->irq_data);
2387         if (retval < 0)
2388                 return retval;
2389 
2390         retval = __setup_irq(irq, desc, act);
2391 
2392         if (retval)
2393                 irq_chip_pm_put(&desc->irq_data);
2394 
2395         return retval;
2396 }
2397 
2398 /**
2399  *      __request_percpu_irq - allocate a percpu interrupt line
2400  *      @irq: Interrupt line to allocate
2401  *      @handler: Function to be called when the IRQ occurs.
2402  *      @flags: Interrupt type flags (IRQF_TIMER only)
2403  *      @devname: An ascii name for the claiming device
2404  *      @dev_id: A percpu cookie passed back to the handler function
2405  *
2406  *      This call allocates interrupt resources and enables the
2407  *      interrupt on the local CPU. If the interrupt is supposed to be
2408  *      enabled on other CPUs, it has to be done on each CPU using
2409  *      enable_percpu_irq().
2410  *
2411  *      Dev_id must be globally unique. It is a per-cpu variable, and
2412  *      the handler gets called with the interrupted CPU's instance of
2413  *      that variable.
2414  */
2415 int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
2416                          unsigned long flags, const char *devname,
2417                          void __percpu *dev_id)
2418 {
2419         struct irqaction *action;
2420         struct irq_desc *desc;
2421         int retval;
2422 
2423         if (!dev_id)
2424                 return -EINVAL;
2425 
2426         desc = irq_to_desc(irq);
2427         if (!desc || !irq_settings_can_request(desc) ||
2428             !irq_settings_is_per_cpu_devid(desc))
2429                 return -EINVAL;
2430 
2431         if (flags && flags != IRQF_TIMER)
2432                 return -EINVAL;
2433 
2434         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2435         if (!action)
2436                 return -ENOMEM;
2437 
2438         action->handler = handler;
2439         action->flags = flags | IRQF_PERCPU | IRQF_NO_SUSPEND;
2440         action->name = devname;
2441         action->percpu_dev_id = dev_id;
2442 
2443         retval = irq_chip_pm_get(&desc->irq_data);
2444         if (retval < 0) {
2445                 kfree(action);
2446                 return retval;
2447         }
2448 
2449         retval = __setup_irq(irq, desc, action);
2450 
2451         if (retval) {
2452                 irq_chip_pm_put(&desc->irq_data);
2453                 kfree(action);
2454         }
2455 
2456         return retval;
2457 }
2458 EXPORT_SYMBOL_GPL(__request_percpu_irq);
2459 
2460 /**
2461  *      request_percpu_nmi - allocate a percpu interrupt line for NMI delivery
2462  *      @irq: Interrupt line to allocate
2463  *      @handler: Function to be called when the IRQ occurs.
2464  *      @name: An ascii name for the claiming device
2465  *      @dev_id: A percpu cookie passed back to the handler function
2466  *
2467  *      This call allocates interrupt resources for a per CPU NMI. Per CPU NMIs
2468  *      have to be setup on each CPU by calling prepare_percpu_nmi() before
2469  *      being enabled on the same CPU by using enable_percpu_nmi().
2470  *
2471  *      Dev_id must be globally unique. It is a per-cpu variable, and
2472  *      the handler gets called with the interrupted CPU's instance of
2473  *      that variable.
2474  *
2475  *      Interrupt lines requested for NMI delivering should have auto enabling
2476  *      setting disabled.
2477  *
2478  *      If the interrupt line cannot be used to deliver NMIs, function
2479  *      will fail returning a negative value.
2480  */
2481 int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
2482                        const char *name, void __percpu *dev_id)
2483 {
2484         struct irqaction *action;
2485         struct irq_desc *desc;
2486         unsigned long flags;
2487         int retval;
2488 
2489         if (!handler)
2490                 return -EINVAL;
2491 
2492         desc = irq_to_desc(irq);
2493 
2494         if (!desc || !irq_settings_can_request(desc) ||
2495             !irq_settings_is_per_cpu_devid(desc) ||
2496             irq_settings_can_autoenable(desc) ||
2497             !irq_supports_nmi(desc))
2498                 return -EINVAL;
2499 
2500         /* The line cannot already be NMI */
2501         if (desc->istate & IRQS_NMI)
2502                 return -EINVAL;
2503 
2504         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2505         if (!action)
2506                 return -ENOMEM;
2507 
2508         action->handler = handler;
2509         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND | IRQF_NO_THREAD
2510                 | IRQF_NOBALANCING;
2511         action->name = name;
2512         action->percpu_dev_id = dev_id;
2513 
2514         retval = irq_chip_pm_get(&desc->irq_data);
2515         if (retval < 0)
2516                 goto err_out;
2517 
2518         retval = __setup_irq(irq, desc, action);
2519         if (retval)
2520                 goto err_irq_setup;
2521 
2522         raw_spin_lock_irqsave(&desc->lock, flags);
2523         desc->istate |= IRQS_NMI;
2524         raw_spin_unlock_irqrestore(&desc->lock, flags);
2525 
2526         return 0;
2527 
2528 err_irq_setup:
2529         irq_chip_pm_put(&desc->irq_data);
2530 err_out:
2531         kfree(action);
2532 
2533         return retval;
2534 }
2535 
2536 /**
2537  *      prepare_percpu_nmi - performs CPU local setup for NMI delivery
2538  *      @irq: Interrupt line to prepare for NMI delivery
2539  *
2540  *      This call prepares an interrupt line to deliver NMI on the current CPU,
2541  *      before that interrupt line gets enabled with enable_percpu_nmi().
2542  *
2543  *      As a CPU local operation, this should be called from non-preemptible
2544  *      context.
2545  *
2546  *      If the interrupt line cannot be used to deliver NMIs, function
2547  *      will fail returning a negative value.
2548  */
2549 int prepare_percpu_nmi(unsigned int irq)
2550 {
2551         unsigned long flags;
2552         struct irq_desc *desc;
2553         int ret = 0;
2554 
2555         WARN_ON(preemptible());
2556 
2557         desc = irq_get_desc_lock(irq, &flags,
2558                                  IRQ_GET_DESC_CHECK_PERCPU);
2559         if (!desc)
2560                 return -EINVAL;
2561 
2562         if (WARN(!(desc->istate & IRQS_NMI),
2563                  KERN_ERR "prepare_percpu_nmi called for a non-NMI interrupt: irq %u\n",
2564                  irq)) {
2565                 ret = -EINVAL;
2566                 goto out;
2567         }
2568 
2569         ret = irq_nmi_setup(desc);
2570         if (ret) {
2571                 pr_err("Failed to setup NMI delivery: irq %u\n", irq);
2572                 goto out;
2573         }
2574 
2575 out:
2576         irq_put_desc_unlock(desc, flags);
2577         return ret;
2578 }
2579 
2580 /**
2581  *      teardown_percpu_nmi - undoes NMI setup of IRQ line
2582  *      @irq: Interrupt line from which CPU local NMI configuration should be
2583  *            removed
2584  *
2585  *      This call undoes the setup done by prepare_percpu_nmi().
2586  *
2587  *      IRQ line should not be enabled for the current CPU.
2588  *
2589  *      As a CPU local operation, this should be called from non-preemptible
2590  *      context.
2591  */
2592 void teardown_percpu_nmi(unsigned int irq)
2593 {
2594         unsigned long flags;
2595         struct irq_desc *desc;
2596 
2597         WARN_ON(preemptible());
2598 
2599         desc = irq_get_desc_lock(irq, &flags,
2600                                  IRQ_GET_DESC_CHECK_PERCPU);
2601         if (!desc)
2602                 return;
2603 
2604         if (WARN_ON(!(desc->istate & IRQS_NMI)))
2605                 goto out;
2606 
2607         irq_nmi_teardown(desc);
2608 out:
2609         irq_put_desc_unlock(desc, flags);
2610 }
2611 
2612 int __irq_get_irqchip_state(struct irq_data *data, enum irqchip_irq_state which,
2613                             bool *state)
2614 {
2615         struct irq_chip *chip;
2616         int err = -EINVAL;
2617 
2618         do {
2619                 chip = irq_data_get_irq_chip(data);
2620                 if (chip->irq_get_irqchip_state)
2621                         break;
2622 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
2623                 data = data->parent_data;
2624 #else
2625                 data = NULL;
2626 #endif
2627         } while (data);
2628 
2629         if (data)
2630                 err = chip->irq_get_irqchip_state(data, which, state);
2631         return err;
2632 }
2633 
2634 /**
2635  *      irq_get_irqchip_state - returns the irqchip state of a interrupt.
2636  *      @irq: Interrupt line that is forwarded to a VM
2637  *      @which: One of IRQCHIP_STATE_* the caller wants to know about
2638  *      @state: a pointer to a boolean where the state is to be storeed
2639  *
2640  *      This call snapshots the internal irqchip state of an
2641  *      interrupt, returning into @state the bit corresponding to
2642  *      stage @which
2643  *
2644  *      This function should be called with preemption disabled if the
2645  *      interrupt controller has per-cpu registers.
2646  */
2647 int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
2648                           bool *state)
2649 {
2650         struct irq_desc *desc;
2651         struct irq_data *data;
2652         unsigned long flags;
2653         int err = -EINVAL;
2654 
2655         desc = irq_get_desc_buslock(irq, &flags, 0);
2656         if (!desc)
2657                 return err;
2658 
2659         data = irq_desc_get_irq_data(desc);
2660 
2661         err = __irq_get_irqchip_state(data, which, state);
2662 
2663         irq_put_desc_busunlock(desc, flags);
2664         return err;
2665 }
2666 EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
2667 
2668 /**
2669  *      irq_set_irqchip_state - set the state of a forwarded interrupt.
2670  *      @irq: Interrupt line that is forwarded to a VM
2671  *      @which: State to be restored (one of IRQCHIP_STATE_*)
2672  *      @val: Value corresponding to @which
2673  *
2674  *      This call sets the internal irqchip state of an interrupt,
2675  *      depending on the value of @which.
2676  *
2677  *      This function should be called with preemption disabled if the
2678  *      interrupt controller has per-cpu registers.
2679  */
2680 int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
2681                           bool val)
2682 {
2683         struct irq_desc *desc;
2684         struct irq_data *data;
2685         struct irq_chip *chip;
2686         unsigned long flags;
2687         int err = -EINVAL;
2688 
2689         desc = irq_get_desc_buslock(irq, &flags, 0);
2690         if (!desc)
2691                 return err;
2692 
2693         data = irq_desc_get_irq_data(desc);
2694 
2695         do {
2696                 chip = irq_data_get_irq_chip(data);
2697                 if (chip->irq_set_irqchip_state)
2698                         break;
2699 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
2700                 data = data->parent_data;
2701 #else
2702                 data = NULL;
2703 #endif
2704         } while (data);
2705 
2706         if (data)
2707                 err = chip->irq_set_irqchip_state(data, which, val);
2708 
2709         irq_put_desc_busunlock(desc, flags);
2710         return err;
2711 }
2712 EXPORT_SYMBOL_GPL(irq_set_irqchip_state);