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TOMOYO Linux Cross Reference
Linux/kernel/irq/manage.c

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  1 /*
  2  * linux/kernel/irq/manage.c
  3  *
  4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
  5  * Copyright (C) 2005-2006 Thomas Gleixner
  6  *
  7  * This file contains driver APIs to the irq subsystem.
  8  */
  9 
 10 #define pr_fmt(fmt) "genirq: " fmt
 11 
 12 #include <linux/irq.h>
 13 #include <linux/kthread.h>
 14 #include <linux/module.h>
 15 #include <linux/random.h>
 16 #include <linux/interrupt.h>
 17 #include <linux/slab.h>
 18 #include <linux/sched.h>
 19 #include <linux/sched/rt.h>
 20 #include <linux/task_work.h>
 21 
 22 #include "internals.h"
 23 
 24 #ifdef CONFIG_IRQ_FORCED_THREADING
 25 __read_mostly bool force_irqthreads;
 26 
 27 static int __init setup_forced_irqthreads(char *arg)
 28 {
 29         force_irqthreads = true;
 30         return 0;
 31 }
 32 early_param("threadirqs", setup_forced_irqthreads);
 33 #endif
 34 
 35 static void __synchronize_hardirq(struct irq_desc *desc)
 36 {
 37         bool inprogress;
 38 
 39         do {
 40                 unsigned long flags;
 41 
 42                 /*
 43                  * Wait until we're out of the critical section.  This might
 44                  * give the wrong answer due to the lack of memory barriers.
 45                  */
 46                 while (irqd_irq_inprogress(&desc->irq_data))
 47                         cpu_relax();
 48 
 49                 /* Ok, that indicated we're done: double-check carefully. */
 50                 raw_spin_lock_irqsave(&desc->lock, flags);
 51                 inprogress = irqd_irq_inprogress(&desc->irq_data);
 52                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 53 
 54                 /* Oops, that failed? */
 55         } while (inprogress);
 56 }
 57 
 58 /**
 59  *      synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
 60  *      @irq: interrupt number to wait for
 61  *
 62  *      This function waits for any pending hard IRQ handlers for this
 63  *      interrupt to complete before returning. If you use this
 64  *      function while holding a resource the IRQ handler may need you
 65  *      will deadlock. It does not take associated threaded handlers
 66  *      into account.
 67  *
 68  *      Do not use this for shutdown scenarios where you must be sure
 69  *      that all parts (hardirq and threaded handler) have completed.
 70  *
 71  *      Returns: false if a threaded handler is active.
 72  *
 73  *      This function may be called - with care - from IRQ context.
 74  */
 75 bool synchronize_hardirq(unsigned int irq)
 76 {
 77         struct irq_desc *desc = irq_to_desc(irq);
 78 
 79         if (desc) {
 80                 __synchronize_hardirq(desc);
 81                 return !atomic_read(&desc->threads_active);
 82         }
 83 
 84         return true;
 85 }
 86 EXPORT_SYMBOL(synchronize_hardirq);
 87 
 88 /**
 89  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
 90  *      @irq: interrupt number to wait for
 91  *
 92  *      This function waits for any pending IRQ handlers for this interrupt
 93  *      to complete before returning. If you use this function while
 94  *      holding a resource the IRQ handler may need you will deadlock.
 95  *
 96  *      This function may be called - with care - from IRQ context.
 97  */
 98 void synchronize_irq(unsigned int irq)
 99 {
100         struct irq_desc *desc = irq_to_desc(irq);
101 
102         if (desc) {
103                 __synchronize_hardirq(desc);
104                 /*
105                  * We made sure that no hardirq handler is
106                  * running. Now verify that no threaded handlers are
107                  * active.
108                  */
109                 wait_event(desc->wait_for_threads,
110                            !atomic_read(&desc->threads_active));
111         }
112 }
113 EXPORT_SYMBOL(synchronize_irq);
114 
115 #ifdef CONFIG_SMP
116 cpumask_var_t irq_default_affinity;
117 
118 /**
119  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
120  *      @irq:           Interrupt to check
121  *
122  */
123 int irq_can_set_affinity(unsigned int irq)
124 {
125         struct irq_desc *desc = irq_to_desc(irq);
126 
127         if (!desc || !irqd_can_balance(&desc->irq_data) ||
128             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
129                 return 0;
130 
131         return 1;
132 }
133 
134 /**
135  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
136  *      @desc:          irq descriptor which has affitnity changed
137  *
138  *      We just set IRQTF_AFFINITY and delegate the affinity setting
139  *      to the interrupt thread itself. We can not call
140  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
141  *      code can be called from hard interrupt context.
142  */
143 void irq_set_thread_affinity(struct irq_desc *desc)
144 {
145         struct irqaction *action = desc->action;
146 
147         while (action) {
148                 if (action->thread)
149                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
150                 action = action->next;
151         }
152 }
153 
154 #ifdef CONFIG_GENERIC_PENDING_IRQ
155 static inline bool irq_can_move_pcntxt(struct irq_data *data)
156 {
157         return irqd_can_move_in_process_context(data);
158 }
159 static inline bool irq_move_pending(struct irq_data *data)
160 {
161         return irqd_is_setaffinity_pending(data);
162 }
163 static inline void
164 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
165 {
166         cpumask_copy(desc->pending_mask, mask);
167 }
168 static inline void
169 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
170 {
171         cpumask_copy(mask, desc->pending_mask);
172 }
173 #else
174 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
175 static inline bool irq_move_pending(struct irq_data *data) { return false; }
176 static inline void
177 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
178 static inline void
179 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
180 #endif
181 
182 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
183                         bool force)
184 {
185         struct irq_desc *desc = irq_data_to_desc(data);
186         struct irq_chip *chip = irq_data_get_irq_chip(data);
187         int ret;
188 
189         ret = chip->irq_set_affinity(data, mask, force);
190         switch (ret) {
191         case IRQ_SET_MASK_OK:
192         case IRQ_SET_MASK_OK_DONE:
193                 cpumask_copy(data->affinity, mask);
194         case IRQ_SET_MASK_OK_NOCOPY:
195                 irq_set_thread_affinity(desc);
196                 ret = 0;
197         }
198 
199         return ret;
200 }
201 
202 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
203                             bool force)
204 {
205         struct irq_chip *chip = irq_data_get_irq_chip(data);
206         struct irq_desc *desc = irq_data_to_desc(data);
207         int ret = 0;
208 
209         if (!chip || !chip->irq_set_affinity)
210                 return -EINVAL;
211 
212         if (irq_can_move_pcntxt(data)) {
213                 ret = irq_do_set_affinity(data, mask, force);
214         } else {
215                 irqd_set_move_pending(data);
216                 irq_copy_pending(desc, mask);
217         }
218 
219         if (desc->affinity_notify) {
220                 kref_get(&desc->affinity_notify->kref);
221                 schedule_work(&desc->affinity_notify->work);
222         }
223         irqd_set(data, IRQD_AFFINITY_SET);
224 
225         return ret;
226 }
227 
228 int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
229 {
230         struct irq_desc *desc = irq_to_desc(irq);
231         unsigned long flags;
232         int ret;
233 
234         if (!desc)
235                 return -EINVAL;
236 
237         raw_spin_lock_irqsave(&desc->lock, flags);
238         ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
239         raw_spin_unlock_irqrestore(&desc->lock, flags);
240         return ret;
241 }
242 
243 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
244 {
245         unsigned long flags;
246         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
247 
248         if (!desc)
249                 return -EINVAL;
250         desc->affinity_hint = m;
251         irq_put_desc_unlock(desc, flags);
252         /* set the initial affinity to prevent every interrupt being on CPU0 */
253         if (m)
254                 __irq_set_affinity(irq, m, false);
255         return 0;
256 }
257 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
258 
259 static void irq_affinity_notify(struct work_struct *work)
260 {
261         struct irq_affinity_notify *notify =
262                 container_of(work, struct irq_affinity_notify, work);
263         struct irq_desc *desc = irq_to_desc(notify->irq);
264         cpumask_var_t cpumask;
265         unsigned long flags;
266 
267         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
268                 goto out;
269 
270         raw_spin_lock_irqsave(&desc->lock, flags);
271         if (irq_move_pending(&desc->irq_data))
272                 irq_get_pending(cpumask, desc);
273         else
274                 cpumask_copy(cpumask, desc->irq_data.affinity);
275         raw_spin_unlock_irqrestore(&desc->lock, flags);
276 
277         notify->notify(notify, cpumask);
278 
279         free_cpumask_var(cpumask);
280 out:
281         kref_put(&notify->kref, notify->release);
282 }
283 
284 /**
285  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
286  *      @irq:           Interrupt for which to enable/disable notification
287  *      @notify:        Context for notification, or %NULL to disable
288  *                      notification.  Function pointers must be initialised;
289  *                      the other fields will be initialised by this function.
290  *
291  *      Must be called in process context.  Notification may only be enabled
292  *      after the IRQ is allocated and must be disabled before the IRQ is
293  *      freed using free_irq().
294  */
295 int
296 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
297 {
298         struct irq_desc *desc = irq_to_desc(irq);
299         struct irq_affinity_notify *old_notify;
300         unsigned long flags;
301 
302         /* The release function is promised process context */
303         might_sleep();
304 
305         if (!desc)
306                 return -EINVAL;
307 
308         /* Complete initialisation of *notify */
309         if (notify) {
310                 notify->irq = irq;
311                 kref_init(&notify->kref);
312                 INIT_WORK(&notify->work, irq_affinity_notify);
313         }
314 
315         raw_spin_lock_irqsave(&desc->lock, flags);
316         old_notify = desc->affinity_notify;
317         desc->affinity_notify = notify;
318         raw_spin_unlock_irqrestore(&desc->lock, flags);
319 
320         if (old_notify)
321                 kref_put(&old_notify->kref, old_notify->release);
322 
323         return 0;
324 }
325 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
326 
327 #ifndef CONFIG_AUTO_IRQ_AFFINITY
328 /*
329  * Generic version of the affinity autoselector.
330  */
331 static int
332 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
333 {
334         struct cpumask *set = irq_default_affinity;
335         int node = desc->irq_data.node;
336 
337         /* Excludes PER_CPU and NO_BALANCE interrupts */
338         if (!irq_can_set_affinity(irq))
339                 return 0;
340 
341         /*
342          * Preserve an userspace affinity setup, but make sure that
343          * one of the targets is online.
344          */
345         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
346                 if (cpumask_intersects(desc->irq_data.affinity,
347                                        cpu_online_mask))
348                         set = desc->irq_data.affinity;
349                 else
350                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
351         }
352 
353         cpumask_and(mask, cpu_online_mask, set);
354         if (node != NUMA_NO_NODE) {
355                 const struct cpumask *nodemask = cpumask_of_node(node);
356 
357                 /* make sure at least one of the cpus in nodemask is online */
358                 if (cpumask_intersects(mask, nodemask))
359                         cpumask_and(mask, mask, nodemask);
360         }
361         irq_do_set_affinity(&desc->irq_data, mask, false);
362         return 0;
363 }
364 #else
365 static inline int
366 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
367 {
368         return irq_select_affinity(irq);
369 }
370 #endif
371 
372 /*
373  * Called when affinity is set via /proc/irq
374  */
375 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
376 {
377         struct irq_desc *desc = irq_to_desc(irq);
378         unsigned long flags;
379         int ret;
380 
381         raw_spin_lock_irqsave(&desc->lock, flags);
382         ret = setup_affinity(irq, desc, mask);
383         raw_spin_unlock_irqrestore(&desc->lock, flags);
384         return ret;
385 }
386 
387 #else
388 static inline int
389 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
390 {
391         return 0;
392 }
393 #endif
394 
395 void __disable_irq(struct irq_desc *desc, unsigned int irq)
396 {
397         if (!desc->depth++)
398                 irq_disable(desc);
399 }
400 
401 static int __disable_irq_nosync(unsigned int irq)
402 {
403         unsigned long flags;
404         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
405 
406         if (!desc)
407                 return -EINVAL;
408         __disable_irq(desc, irq);
409         irq_put_desc_busunlock(desc, flags);
410         return 0;
411 }
412 
413 /**
414  *      disable_irq_nosync - disable an irq without waiting
415  *      @irq: Interrupt to disable
416  *
417  *      Disable the selected interrupt line.  Disables and Enables are
418  *      nested.
419  *      Unlike disable_irq(), this function does not ensure existing
420  *      instances of the IRQ handler have completed before returning.
421  *
422  *      This function may be called from IRQ context.
423  */
424 void disable_irq_nosync(unsigned int irq)
425 {
426         __disable_irq_nosync(irq);
427 }
428 EXPORT_SYMBOL(disable_irq_nosync);
429 
430 /**
431  *      disable_irq - disable an irq and wait for completion
432  *      @irq: Interrupt to disable
433  *
434  *      Disable the selected interrupt line.  Enables and Disables are
435  *      nested.
436  *      This function waits for any pending IRQ handlers for this interrupt
437  *      to complete before returning. If you use this function while
438  *      holding a resource the IRQ handler may need you will deadlock.
439  *
440  *      This function may be called - with care - from IRQ context.
441  */
442 void disable_irq(unsigned int irq)
443 {
444         if (!__disable_irq_nosync(irq))
445                 synchronize_irq(irq);
446 }
447 EXPORT_SYMBOL(disable_irq);
448 
449 /**
450  *      disable_hardirq - disables an irq and waits for hardirq completion
451  *      @irq: Interrupt to disable
452  *
453  *      Disable the selected interrupt line.  Enables and Disables are
454  *      nested.
455  *      This function waits for any pending hard IRQ handlers for this
456  *      interrupt to complete before returning. If you use this function while
457  *      holding a resource the hard IRQ handler may need you will deadlock.
458  *
459  *      When used to optimistically disable an interrupt from atomic context
460  *      the return value must be checked.
461  *
462  *      Returns: false if a threaded handler is active.
463  *
464  *      This function may be called - with care - from IRQ context.
465  */
466 bool disable_hardirq(unsigned int irq)
467 {
468         if (!__disable_irq_nosync(irq))
469                 return synchronize_hardirq(irq);
470 
471         return false;
472 }
473 EXPORT_SYMBOL_GPL(disable_hardirq);
474 
475 void __enable_irq(struct irq_desc *desc, unsigned int irq)
476 {
477         switch (desc->depth) {
478         case 0:
479  err_out:
480                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
481                 break;
482         case 1: {
483                 if (desc->istate & IRQS_SUSPENDED)
484                         goto err_out;
485                 /* Prevent probing on this irq: */
486                 irq_settings_set_noprobe(desc);
487                 irq_enable(desc);
488                 check_irq_resend(desc, irq);
489                 /* fall-through */
490         }
491         default:
492                 desc->depth--;
493         }
494 }
495 
496 /**
497  *      enable_irq - enable handling of an irq
498  *      @irq: Interrupt to enable
499  *
500  *      Undoes the effect of one call to disable_irq().  If this
501  *      matches the last disable, processing of interrupts on this
502  *      IRQ line is re-enabled.
503  *
504  *      This function may be called from IRQ context only when
505  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
506  */
507 void enable_irq(unsigned int irq)
508 {
509         unsigned long flags;
510         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
511 
512         if (!desc)
513                 return;
514         if (WARN(!desc->irq_data.chip,
515                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
516                 goto out;
517 
518         __enable_irq(desc, irq);
519 out:
520         irq_put_desc_busunlock(desc, flags);
521 }
522 EXPORT_SYMBOL(enable_irq);
523 
524 static int set_irq_wake_real(unsigned int irq, unsigned int on)
525 {
526         struct irq_desc *desc = irq_to_desc(irq);
527         int ret = -ENXIO;
528 
529         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
530                 return 0;
531 
532         if (desc->irq_data.chip->irq_set_wake)
533                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
534 
535         return ret;
536 }
537 
538 /**
539  *      irq_set_irq_wake - control irq power management wakeup
540  *      @irq:   interrupt to control
541  *      @on:    enable/disable power management wakeup
542  *
543  *      Enable/disable power management wakeup mode, which is
544  *      disabled by default.  Enables and disables must match,
545  *      just as they match for non-wakeup mode support.
546  *
547  *      Wakeup mode lets this IRQ wake the system from sleep
548  *      states like "suspend to RAM".
549  */
550 int irq_set_irq_wake(unsigned int irq, unsigned int on)
551 {
552         unsigned long flags;
553         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
554         int ret = 0;
555 
556         if (!desc)
557                 return -EINVAL;
558 
559         /* wakeup-capable irqs can be shared between drivers that
560          * don't need to have the same sleep mode behaviors.
561          */
562         if (on) {
563                 if (desc->wake_depth++ == 0) {
564                         ret = set_irq_wake_real(irq, on);
565                         if (ret)
566                                 desc->wake_depth = 0;
567                         else
568                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
569                 }
570         } else {
571                 if (desc->wake_depth == 0) {
572                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
573                 } else if (--desc->wake_depth == 0) {
574                         ret = set_irq_wake_real(irq, on);
575                         if (ret)
576                                 desc->wake_depth = 1;
577                         else
578                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
579                 }
580         }
581         irq_put_desc_busunlock(desc, flags);
582         return ret;
583 }
584 EXPORT_SYMBOL(irq_set_irq_wake);
585 
586 /*
587  * Internal function that tells the architecture code whether a
588  * particular irq has been exclusively allocated or is available
589  * for driver use.
590  */
591 int can_request_irq(unsigned int irq, unsigned long irqflags)
592 {
593         unsigned long flags;
594         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
595         int canrequest = 0;
596 
597         if (!desc)
598                 return 0;
599 
600         if (irq_settings_can_request(desc)) {
601                 if (!desc->action ||
602                     irqflags & desc->action->flags & IRQF_SHARED)
603                         canrequest = 1;
604         }
605         irq_put_desc_unlock(desc, flags);
606         return canrequest;
607 }
608 
609 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
610                       unsigned long flags)
611 {
612         struct irq_chip *chip = desc->irq_data.chip;
613         int ret, unmask = 0;
614 
615         if (!chip || !chip->irq_set_type) {
616                 /*
617                  * IRQF_TRIGGER_* but the PIC does not support multiple
618                  * flow-types?
619                  */
620                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
621                          chip ? (chip->name ? : "unknown") : "unknown");
622                 return 0;
623         }
624 
625         flags &= IRQ_TYPE_SENSE_MASK;
626 
627         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
628                 if (!irqd_irq_masked(&desc->irq_data))
629                         mask_irq(desc);
630                 if (!irqd_irq_disabled(&desc->irq_data))
631                         unmask = 1;
632         }
633 
634         /* caller masked out all except trigger mode flags */
635         ret = chip->irq_set_type(&desc->irq_data, flags);
636 
637         switch (ret) {
638         case IRQ_SET_MASK_OK:
639         case IRQ_SET_MASK_OK_DONE:
640                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
641                 irqd_set(&desc->irq_data, flags);
642 
643         case IRQ_SET_MASK_OK_NOCOPY:
644                 flags = irqd_get_trigger_type(&desc->irq_data);
645                 irq_settings_set_trigger_mask(desc, flags);
646                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
647                 irq_settings_clr_level(desc);
648                 if (flags & IRQ_TYPE_LEVEL_MASK) {
649                         irq_settings_set_level(desc);
650                         irqd_set(&desc->irq_data, IRQD_LEVEL);
651                 }
652 
653                 ret = 0;
654                 break;
655         default:
656                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
657                        flags, irq, chip->irq_set_type);
658         }
659         if (unmask)
660                 unmask_irq(desc);
661         return ret;
662 }
663 
664 #ifdef CONFIG_HARDIRQS_SW_RESEND
665 int irq_set_parent(int irq, int parent_irq)
666 {
667         unsigned long flags;
668         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
669 
670         if (!desc)
671                 return -EINVAL;
672 
673         desc->parent_irq = parent_irq;
674 
675         irq_put_desc_unlock(desc, flags);
676         return 0;
677 }
678 #endif
679 
680 /*
681  * Default primary interrupt handler for threaded interrupts. Is
682  * assigned as primary handler when request_threaded_irq is called
683  * with handler == NULL. Useful for oneshot interrupts.
684  */
685 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
686 {
687         return IRQ_WAKE_THREAD;
688 }
689 
690 /*
691  * Primary handler for nested threaded interrupts. Should never be
692  * called.
693  */
694 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
695 {
696         WARN(1, "Primary handler called for nested irq %d\n", irq);
697         return IRQ_NONE;
698 }
699 
700 static int irq_wait_for_interrupt(struct irqaction *action)
701 {
702         set_current_state(TASK_INTERRUPTIBLE);
703 
704         while (!kthread_should_stop()) {
705 
706                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
707                                        &action->thread_flags)) {
708                         __set_current_state(TASK_RUNNING);
709                         return 0;
710                 }
711                 schedule();
712                 set_current_state(TASK_INTERRUPTIBLE);
713         }
714         __set_current_state(TASK_RUNNING);
715         return -1;
716 }
717 
718 /*
719  * Oneshot interrupts keep the irq line masked until the threaded
720  * handler finished. unmask if the interrupt has not been disabled and
721  * is marked MASKED.
722  */
723 static void irq_finalize_oneshot(struct irq_desc *desc,
724                                  struct irqaction *action)
725 {
726         if (!(desc->istate & IRQS_ONESHOT))
727                 return;
728 again:
729         chip_bus_lock(desc);
730         raw_spin_lock_irq(&desc->lock);
731 
732         /*
733          * Implausible though it may be we need to protect us against
734          * the following scenario:
735          *
736          * The thread is faster done than the hard interrupt handler
737          * on the other CPU. If we unmask the irq line then the
738          * interrupt can come in again and masks the line, leaves due
739          * to IRQS_INPROGRESS and the irq line is masked forever.
740          *
741          * This also serializes the state of shared oneshot handlers
742          * versus "desc->threads_onehsot |= action->thread_mask;" in
743          * irq_wake_thread(). See the comment there which explains the
744          * serialization.
745          */
746         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
747                 raw_spin_unlock_irq(&desc->lock);
748                 chip_bus_sync_unlock(desc);
749                 cpu_relax();
750                 goto again;
751         }
752 
753         /*
754          * Now check again, whether the thread should run. Otherwise
755          * we would clear the threads_oneshot bit of this thread which
756          * was just set.
757          */
758         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
759                 goto out_unlock;
760 
761         desc->threads_oneshot &= ~action->thread_mask;
762 
763         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
764             irqd_irq_masked(&desc->irq_data))
765                 unmask_threaded_irq(desc);
766 
767 out_unlock:
768         raw_spin_unlock_irq(&desc->lock);
769         chip_bus_sync_unlock(desc);
770 }
771 
772 #ifdef CONFIG_SMP
773 /*
774  * Check whether we need to change the affinity of the interrupt thread.
775  */
776 static void
777 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
778 {
779         cpumask_var_t mask;
780         bool valid = true;
781 
782         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
783                 return;
784 
785         /*
786          * In case we are out of memory we set IRQTF_AFFINITY again and
787          * try again next time
788          */
789         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
790                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
791                 return;
792         }
793 
794         raw_spin_lock_irq(&desc->lock);
795         /*
796          * This code is triggered unconditionally. Check the affinity
797          * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
798          */
799         if (desc->irq_data.affinity)
800                 cpumask_copy(mask, desc->irq_data.affinity);
801         else
802                 valid = false;
803         raw_spin_unlock_irq(&desc->lock);
804 
805         if (valid)
806                 set_cpus_allowed_ptr(current, mask);
807         free_cpumask_var(mask);
808 }
809 #else
810 static inline void
811 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
812 #endif
813 
814 /*
815  * Interrupts which are not explicitely requested as threaded
816  * interrupts rely on the implicit bh/preempt disable of the hard irq
817  * context. So we need to disable bh here to avoid deadlocks and other
818  * side effects.
819  */
820 static irqreturn_t
821 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
822 {
823         irqreturn_t ret;
824 
825         local_bh_disable();
826         ret = action->thread_fn(action->irq, action->dev_id);
827         irq_finalize_oneshot(desc, action);
828         local_bh_enable();
829         return ret;
830 }
831 
832 /*
833  * Interrupts explicitly requested as threaded interrupts want to be
834  * preemtible - many of them need to sleep and wait for slow busses to
835  * complete.
836  */
837 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
838                 struct irqaction *action)
839 {
840         irqreturn_t ret;
841 
842         ret = action->thread_fn(action->irq, action->dev_id);
843         irq_finalize_oneshot(desc, action);
844         return ret;
845 }
846 
847 static void wake_threads_waitq(struct irq_desc *desc)
848 {
849         if (atomic_dec_and_test(&desc->threads_active))
850                 wake_up(&desc->wait_for_threads);
851 }
852 
853 static void irq_thread_dtor(struct callback_head *unused)
854 {
855         struct task_struct *tsk = current;
856         struct irq_desc *desc;
857         struct irqaction *action;
858 
859         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
860                 return;
861 
862         action = kthread_data(tsk);
863 
864         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
865                tsk->comm, tsk->pid, action->irq);
866 
867 
868         desc = irq_to_desc(action->irq);
869         /*
870          * If IRQTF_RUNTHREAD is set, we need to decrement
871          * desc->threads_active and wake possible waiters.
872          */
873         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
874                 wake_threads_waitq(desc);
875 
876         /* Prevent a stale desc->threads_oneshot */
877         irq_finalize_oneshot(desc, action);
878 }
879 
880 /*
881  * Interrupt handler thread
882  */
883 static int irq_thread(void *data)
884 {
885         struct callback_head on_exit_work;
886         struct irqaction *action = data;
887         struct irq_desc *desc = irq_to_desc(action->irq);
888         irqreturn_t (*handler_fn)(struct irq_desc *desc,
889                         struct irqaction *action);
890 
891         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
892                                         &action->thread_flags))
893                 handler_fn = irq_forced_thread_fn;
894         else
895                 handler_fn = irq_thread_fn;
896 
897         init_task_work(&on_exit_work, irq_thread_dtor);
898         task_work_add(current, &on_exit_work, false);
899 
900         irq_thread_check_affinity(desc, action);
901 
902         while (!irq_wait_for_interrupt(action)) {
903                 irqreturn_t action_ret;
904 
905                 irq_thread_check_affinity(desc, action);
906 
907                 action_ret = handler_fn(desc, action);
908                 if (action_ret == IRQ_HANDLED)
909                         atomic_inc(&desc->threads_handled);
910 
911                 wake_threads_waitq(desc);
912         }
913 
914         /*
915          * This is the regular exit path. __free_irq() is stopping the
916          * thread via kthread_stop() after calling
917          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
918          * oneshot mask bit can be set. We cannot verify that as we
919          * cannot touch the oneshot mask at this point anymore as
920          * __setup_irq() might have given out currents thread_mask
921          * again.
922          */
923         task_work_cancel(current, irq_thread_dtor);
924         return 0;
925 }
926 
927 /**
928  *      irq_wake_thread - wake the irq thread for the action identified by dev_id
929  *      @irq:           Interrupt line
930  *      @dev_id:        Device identity for which the thread should be woken
931  *
932  */
933 void irq_wake_thread(unsigned int irq, void *dev_id)
934 {
935         struct irq_desc *desc = irq_to_desc(irq);
936         struct irqaction *action;
937         unsigned long flags;
938 
939         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
940                 return;
941 
942         raw_spin_lock_irqsave(&desc->lock, flags);
943         for (action = desc->action; action; action = action->next) {
944                 if (action->dev_id == dev_id) {
945                         if (action->thread)
946                                 __irq_wake_thread(desc, action);
947                         break;
948                 }
949         }
950         raw_spin_unlock_irqrestore(&desc->lock, flags);
951 }
952 EXPORT_SYMBOL_GPL(irq_wake_thread);
953 
954 static void irq_setup_forced_threading(struct irqaction *new)
955 {
956         if (!force_irqthreads)
957                 return;
958         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
959                 return;
960 
961         new->flags |= IRQF_ONESHOT;
962 
963         if (!new->thread_fn) {
964                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
965                 new->thread_fn = new->handler;
966                 new->handler = irq_default_primary_handler;
967         }
968 }
969 
970 static int irq_request_resources(struct irq_desc *desc)
971 {
972         struct irq_data *d = &desc->irq_data;
973         struct irq_chip *c = d->chip;
974 
975         return c->irq_request_resources ? c->irq_request_resources(d) : 0;
976 }
977 
978 static void irq_release_resources(struct irq_desc *desc)
979 {
980         struct irq_data *d = &desc->irq_data;
981         struct irq_chip *c = d->chip;
982 
983         if (c->irq_release_resources)
984                 c->irq_release_resources(d);
985 }
986 
987 /*
988  * Internal function to register an irqaction - typically used to
989  * allocate special interrupts that are part of the architecture.
990  */
991 static int
992 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
993 {
994         struct irqaction *old, **old_ptr;
995         unsigned long flags, thread_mask = 0;
996         int ret, nested, shared = 0;
997         cpumask_var_t mask;
998 
999         if (!desc)
1000                 return -EINVAL;
1001 
1002         if (desc->irq_data.chip == &no_irq_chip)
1003                 return -ENOSYS;
1004         if (!try_module_get(desc->owner))
1005                 return -ENODEV;
1006 
1007         /*
1008          * Check whether the interrupt nests into another interrupt
1009          * thread.
1010          */
1011         nested = irq_settings_is_nested_thread(desc);
1012         if (nested) {
1013                 if (!new->thread_fn) {
1014                         ret = -EINVAL;
1015                         goto out_mput;
1016                 }
1017                 /*
1018                  * Replace the primary handler which was provided from
1019                  * the driver for non nested interrupt handling by the
1020                  * dummy function which warns when called.
1021                  */
1022                 new->handler = irq_nested_primary_handler;
1023         } else {
1024                 if (irq_settings_can_thread(desc))
1025                         irq_setup_forced_threading(new);
1026         }
1027 
1028         /*
1029          * Create a handler thread when a thread function is supplied
1030          * and the interrupt does not nest into another interrupt
1031          * thread.
1032          */
1033         if (new->thread_fn && !nested) {
1034                 struct task_struct *t;
1035                 static const struct sched_param param = {
1036                         .sched_priority = MAX_USER_RT_PRIO/2,
1037                 };
1038 
1039                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1040                                    new->name);
1041                 if (IS_ERR(t)) {
1042                         ret = PTR_ERR(t);
1043                         goto out_mput;
1044                 }
1045 
1046                 sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
1047 
1048                 /*
1049                  * We keep the reference to the task struct even if
1050                  * the thread dies to avoid that the interrupt code
1051                  * references an already freed task_struct.
1052                  */
1053                 get_task_struct(t);
1054                 new->thread = t;
1055                 /*
1056                  * Tell the thread to set its affinity. This is
1057                  * important for shared interrupt handlers as we do
1058                  * not invoke setup_affinity() for the secondary
1059                  * handlers as everything is already set up. Even for
1060                  * interrupts marked with IRQF_NO_BALANCE this is
1061                  * correct as we want the thread to move to the cpu(s)
1062                  * on which the requesting code placed the interrupt.
1063                  */
1064                 set_bit(IRQTF_AFFINITY, &new->thread_flags);
1065         }
1066 
1067         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1068                 ret = -ENOMEM;
1069                 goto out_thread;
1070         }
1071 
1072         /*
1073          * Drivers are often written to work w/o knowledge about the
1074          * underlying irq chip implementation, so a request for a
1075          * threaded irq without a primary hard irq context handler
1076          * requires the ONESHOT flag to be set. Some irq chips like
1077          * MSI based interrupts are per se one shot safe. Check the
1078          * chip flags, so we can avoid the unmask dance at the end of
1079          * the threaded handler for those.
1080          */
1081         if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1082                 new->flags &= ~IRQF_ONESHOT;
1083 
1084         /*
1085          * The following block of code has to be executed atomically
1086          */
1087         raw_spin_lock_irqsave(&desc->lock, flags);
1088         old_ptr = &desc->action;
1089         old = *old_ptr;
1090         if (old) {
1091                 /*
1092                  * Can't share interrupts unless both agree to and are
1093                  * the same type (level, edge, polarity). So both flag
1094                  * fields must have IRQF_SHARED set and the bits which
1095                  * set the trigger type must match. Also all must
1096                  * agree on ONESHOT.
1097                  */
1098                 unsigned int oldtype = irqd_get_trigger_type(&desc->irq_data);
1099 
1100                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1101                     (oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
1102                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
1103                         goto mismatch;
1104 
1105                 /* All handlers must agree on per-cpuness */
1106                 if ((old->flags & IRQF_PERCPU) !=
1107                     (new->flags & IRQF_PERCPU))
1108                         goto mismatch;
1109 
1110                 /* add new interrupt at end of irq queue */
1111                 do {
1112                         /*
1113                          * Or all existing action->thread_mask bits,
1114                          * so we can find the next zero bit for this
1115                          * new action.
1116                          */
1117                         thread_mask |= old->thread_mask;
1118                         old_ptr = &old->next;
1119                         old = *old_ptr;
1120                 } while (old);
1121                 shared = 1;
1122         }
1123 
1124         /*
1125          * Setup the thread mask for this irqaction for ONESHOT. For
1126          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1127          * conditional in irq_wake_thread().
1128          */
1129         if (new->flags & IRQF_ONESHOT) {
1130                 /*
1131                  * Unlikely to have 32 resp 64 irqs sharing one line,
1132                  * but who knows.
1133                  */
1134                 if (thread_mask == ~0UL) {
1135                         ret = -EBUSY;
1136                         goto out_mask;
1137                 }
1138                 /*
1139                  * The thread_mask for the action is or'ed to
1140                  * desc->thread_active to indicate that the
1141                  * IRQF_ONESHOT thread handler has been woken, but not
1142                  * yet finished. The bit is cleared when a thread
1143                  * completes. When all threads of a shared interrupt
1144                  * line have completed desc->threads_active becomes
1145                  * zero and the interrupt line is unmasked. See
1146                  * handle.c:irq_wake_thread() for further information.
1147                  *
1148                  * If no thread is woken by primary (hard irq context)
1149                  * interrupt handlers, then desc->threads_active is
1150                  * also checked for zero to unmask the irq line in the
1151                  * affected hard irq flow handlers
1152                  * (handle_[fasteoi|level]_irq).
1153                  *
1154                  * The new action gets the first zero bit of
1155                  * thread_mask assigned. See the loop above which or's
1156                  * all existing action->thread_mask bits.
1157                  */
1158                 new->thread_mask = 1 << ffz(thread_mask);
1159 
1160         } else if (new->handler == irq_default_primary_handler &&
1161                    !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1162                 /*
1163                  * The interrupt was requested with handler = NULL, so
1164                  * we use the default primary handler for it. But it
1165                  * does not have the oneshot flag set. In combination
1166                  * with level interrupts this is deadly, because the
1167                  * default primary handler just wakes the thread, then
1168                  * the irq lines is reenabled, but the device still
1169                  * has the level irq asserted. Rinse and repeat....
1170                  *
1171                  * While this works for edge type interrupts, we play
1172                  * it safe and reject unconditionally because we can't
1173                  * say for sure which type this interrupt really
1174                  * has. The type flags are unreliable as the
1175                  * underlying chip implementation can override them.
1176                  */
1177                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1178                        irq);
1179                 ret = -EINVAL;
1180                 goto out_mask;
1181         }
1182 
1183         if (!shared) {
1184                 ret = irq_request_resources(desc);
1185                 if (ret) {
1186                         pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1187                                new->name, irq, desc->irq_data.chip->name);
1188                         goto out_mask;
1189                 }
1190 
1191                 init_waitqueue_head(&desc->wait_for_threads);
1192 
1193                 /* Setup the type (level, edge polarity) if configured: */
1194                 if (new->flags & IRQF_TRIGGER_MASK) {
1195                         ret = __irq_set_trigger(desc, irq,
1196                                         new->flags & IRQF_TRIGGER_MASK);
1197 
1198                         if (ret) {
1199                                 irq_release_resources(desc);
1200                                 goto out_mask;
1201                         }
1202                 }
1203 
1204                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1205                                   IRQS_ONESHOT | IRQS_WAITING);
1206                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1207 
1208                 if (new->flags & IRQF_PERCPU) {
1209                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1210                         irq_settings_set_per_cpu(desc);
1211                 }
1212 
1213                 if (new->flags & IRQF_ONESHOT)
1214                         desc->istate |= IRQS_ONESHOT;
1215 
1216                 if (irq_settings_can_autoenable(desc))
1217                         irq_startup(desc, true);
1218                 else
1219                         /* Undo nested disables: */
1220                         desc->depth = 1;
1221 
1222                 /* Exclude IRQ from balancing if requested */
1223                 if (new->flags & IRQF_NOBALANCING) {
1224                         irq_settings_set_no_balancing(desc);
1225                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1226                 }
1227 
1228                 /* Set default affinity mask once everything is setup */
1229                 setup_affinity(irq, desc, mask);
1230 
1231         } else if (new->flags & IRQF_TRIGGER_MASK) {
1232                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1233                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1234 
1235                 if (nmsk != omsk)
1236                         /* hope the handler works with current  trigger mode */
1237                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1238                                    irq, nmsk, omsk);
1239         }
1240 
1241         new->irq = irq;
1242         *old_ptr = new;
1243 
1244         irq_pm_install_action(desc, new);
1245 
1246         /* Reset broken irq detection when installing new handler */
1247         desc->irq_count = 0;
1248         desc->irqs_unhandled = 0;
1249 
1250         /*
1251          * Check whether we disabled the irq via the spurious handler
1252          * before. Reenable it and give it another chance.
1253          */
1254         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1255                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1256                 __enable_irq(desc, irq);
1257         }
1258 
1259         raw_spin_unlock_irqrestore(&desc->lock, flags);
1260 
1261         /*
1262          * Strictly no need to wake it up, but hung_task complains
1263          * when no hard interrupt wakes the thread up.
1264          */
1265         if (new->thread)
1266                 wake_up_process(new->thread);
1267 
1268         register_irq_proc(irq, desc);
1269         new->dir = NULL;
1270         register_handler_proc(irq, new);
1271         free_cpumask_var(mask);
1272 
1273         return 0;
1274 
1275 mismatch:
1276         if (!(new->flags & IRQF_PROBE_SHARED)) {
1277                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1278                        irq, new->flags, new->name, old->flags, old->name);
1279 #ifdef CONFIG_DEBUG_SHIRQ
1280                 dump_stack();
1281 #endif
1282         }
1283         ret = -EBUSY;
1284 
1285 out_mask:
1286         raw_spin_unlock_irqrestore(&desc->lock, flags);
1287         free_cpumask_var(mask);
1288 
1289 out_thread:
1290         if (new->thread) {
1291                 struct task_struct *t = new->thread;
1292 
1293                 new->thread = NULL;
1294                 kthread_stop(t);
1295                 put_task_struct(t);
1296         }
1297 out_mput:
1298         module_put(desc->owner);
1299         return ret;
1300 }
1301 
1302 /**
1303  *      setup_irq - setup an interrupt
1304  *      @irq: Interrupt line to setup
1305  *      @act: irqaction for the interrupt
1306  *
1307  * Used to statically setup interrupts in the early boot process.
1308  */
1309 int setup_irq(unsigned int irq, struct irqaction *act)
1310 {
1311         int retval;
1312         struct irq_desc *desc = irq_to_desc(irq);
1313 
1314         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1315                 return -EINVAL;
1316         chip_bus_lock(desc);
1317         retval = __setup_irq(irq, desc, act);
1318         chip_bus_sync_unlock(desc);
1319 
1320         return retval;
1321 }
1322 EXPORT_SYMBOL_GPL(setup_irq);
1323 
1324 /*
1325  * Internal function to unregister an irqaction - used to free
1326  * regular and special interrupts that are part of the architecture.
1327  */
1328 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1329 {
1330         struct irq_desc *desc = irq_to_desc(irq);
1331         struct irqaction *action, **action_ptr;
1332         unsigned long flags;
1333 
1334         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1335 
1336         if (!desc)
1337                 return NULL;
1338 
1339         raw_spin_lock_irqsave(&desc->lock, flags);
1340 
1341         /*
1342          * There can be multiple actions per IRQ descriptor, find the right
1343          * one based on the dev_id:
1344          */
1345         action_ptr = &desc->action;
1346         for (;;) {
1347                 action = *action_ptr;
1348 
1349                 if (!action) {
1350                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1351                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1352 
1353                         return NULL;
1354                 }
1355 
1356                 if (action->dev_id == dev_id)
1357                         break;
1358                 action_ptr = &action->next;
1359         }
1360 
1361         /* Found it - now remove it from the list of entries: */
1362         *action_ptr = action->next;
1363 
1364         irq_pm_remove_action(desc, action);
1365 
1366         /* If this was the last handler, shut down the IRQ line: */
1367         if (!desc->action) {
1368                 irq_shutdown(desc);
1369                 irq_release_resources(desc);
1370         }
1371 
1372 #ifdef CONFIG_SMP
1373         /* make sure affinity_hint is cleaned up */
1374         if (WARN_ON_ONCE(desc->affinity_hint))
1375                 desc->affinity_hint = NULL;
1376 #endif
1377 
1378         raw_spin_unlock_irqrestore(&desc->lock, flags);
1379 
1380         unregister_handler_proc(irq, action);
1381 
1382         /* Make sure it's not being used on another CPU: */
1383         synchronize_irq(irq);
1384 
1385 #ifdef CONFIG_DEBUG_SHIRQ
1386         /*
1387          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1388          * event to happen even now it's being freed, so let's make sure that
1389          * is so by doing an extra call to the handler ....
1390          *
1391          * ( We do this after actually deregistering it, to make sure that a
1392          *   'real' IRQ doesn't run in * parallel with our fake. )
1393          */
1394         if (action->flags & IRQF_SHARED) {
1395                 local_irq_save(flags);
1396                 action->handler(irq, dev_id);
1397                 local_irq_restore(flags);
1398         }
1399 #endif
1400 
1401         if (action->thread) {
1402                 kthread_stop(action->thread);
1403                 put_task_struct(action->thread);
1404         }
1405 
1406         module_put(desc->owner);
1407         return action;
1408 }
1409 
1410 /**
1411  *      remove_irq - free an interrupt
1412  *      @irq: Interrupt line to free
1413  *      @act: irqaction for the interrupt
1414  *
1415  * Used to remove interrupts statically setup by the early boot process.
1416  */
1417 void remove_irq(unsigned int irq, struct irqaction *act)
1418 {
1419         struct irq_desc *desc = irq_to_desc(irq);
1420 
1421         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1422             __free_irq(irq, act->dev_id);
1423 }
1424 EXPORT_SYMBOL_GPL(remove_irq);
1425 
1426 /**
1427  *      free_irq - free an interrupt allocated with request_irq
1428  *      @irq: Interrupt line to free
1429  *      @dev_id: Device identity to free
1430  *
1431  *      Remove an interrupt handler. The handler is removed and if the
1432  *      interrupt line is no longer in use by any driver it is disabled.
1433  *      On a shared IRQ the caller must ensure the interrupt is disabled
1434  *      on the card it drives before calling this function. The function
1435  *      does not return until any executing interrupts for this IRQ
1436  *      have completed.
1437  *
1438  *      This function must not be called from interrupt context.
1439  */
1440 void free_irq(unsigned int irq, void *dev_id)
1441 {
1442         struct irq_desc *desc = irq_to_desc(irq);
1443 
1444         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1445                 return;
1446 
1447 #ifdef CONFIG_SMP
1448         if (WARN_ON(desc->affinity_notify))
1449                 desc->affinity_notify = NULL;
1450 #endif
1451 
1452         chip_bus_lock(desc);
1453         kfree(__free_irq(irq, dev_id));
1454         chip_bus_sync_unlock(desc);
1455 }
1456 EXPORT_SYMBOL(free_irq);
1457 
1458 /**
1459  *      request_threaded_irq - allocate an interrupt line
1460  *      @irq: Interrupt line to allocate
1461  *      @handler: Function to be called when the IRQ occurs.
1462  *                Primary handler for threaded interrupts
1463  *                If NULL and thread_fn != NULL the default
1464  *                primary handler is installed
1465  *      @thread_fn: Function called from the irq handler thread
1466  *                  If NULL, no irq thread is created
1467  *      @irqflags: Interrupt type flags
1468  *      @devname: An ascii name for the claiming device
1469  *      @dev_id: A cookie passed back to the handler function
1470  *
1471  *      This call allocates interrupt resources and enables the
1472  *      interrupt line and IRQ handling. From the point this
1473  *      call is made your handler function may be invoked. Since
1474  *      your handler function must clear any interrupt the board
1475  *      raises, you must take care both to initialise your hardware
1476  *      and to set up the interrupt handler in the right order.
1477  *
1478  *      If you want to set up a threaded irq handler for your device
1479  *      then you need to supply @handler and @thread_fn. @handler is
1480  *      still called in hard interrupt context and has to check
1481  *      whether the interrupt originates from the device. If yes it
1482  *      needs to disable the interrupt on the device and return
1483  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1484  *      @thread_fn. This split handler design is necessary to support
1485  *      shared interrupts.
1486  *
1487  *      Dev_id must be globally unique. Normally the address of the
1488  *      device data structure is used as the cookie. Since the handler
1489  *      receives this value it makes sense to use it.
1490  *
1491  *      If your interrupt is shared you must pass a non NULL dev_id
1492  *      as this is required when freeing the interrupt.
1493  *
1494  *      Flags:
1495  *
1496  *      IRQF_SHARED             Interrupt is shared
1497  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1498  *
1499  */
1500 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1501                          irq_handler_t thread_fn, unsigned long irqflags,
1502                          const char *devname, void *dev_id)
1503 {
1504         struct irqaction *action;
1505         struct irq_desc *desc;
1506         int retval;
1507 
1508         /*
1509          * Sanity-check: shared interrupts must pass in a real dev-ID,
1510          * otherwise we'll have trouble later trying to figure out
1511          * which interrupt is which (messes up the interrupt freeing
1512          * logic etc).
1513          *
1514          * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
1515          * it cannot be set along with IRQF_NO_SUSPEND.
1516          */
1517         if (((irqflags & IRQF_SHARED) && !dev_id) ||
1518             (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
1519             ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
1520                 return -EINVAL;
1521 
1522         desc = irq_to_desc(irq);
1523         if (!desc)
1524                 return -EINVAL;
1525 
1526         if (!irq_settings_can_request(desc) ||
1527             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1528                 return -EINVAL;
1529 
1530         if (!handler) {
1531                 if (!thread_fn)
1532                         return -EINVAL;
1533                 handler = irq_default_primary_handler;
1534         }
1535 
1536         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1537         if (!action)
1538                 return -ENOMEM;
1539 
1540         action->handler = handler;
1541         action->thread_fn = thread_fn;
1542         action->flags = irqflags;
1543         action->name = devname;
1544         action->dev_id = dev_id;
1545 
1546         chip_bus_lock(desc);
1547         retval = __setup_irq(irq, desc, action);
1548         chip_bus_sync_unlock(desc);
1549 
1550         if (retval)
1551                 kfree(action);
1552 
1553 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1554         if (!retval && (irqflags & IRQF_SHARED)) {
1555                 /*
1556                  * It's a shared IRQ -- the driver ought to be prepared for it
1557                  * to happen immediately, so let's make sure....
1558                  * We disable the irq to make sure that a 'real' IRQ doesn't
1559                  * run in parallel with our fake.
1560                  */
1561                 unsigned long flags;
1562 
1563                 disable_irq(irq);
1564                 local_irq_save(flags);
1565 
1566                 handler(irq, dev_id);
1567 
1568                 local_irq_restore(flags);
1569                 enable_irq(irq);
1570         }
1571 #endif
1572         return retval;
1573 }
1574 EXPORT_SYMBOL(request_threaded_irq);
1575 
1576 /**
1577  *      request_any_context_irq - allocate an interrupt line
1578  *      @irq: Interrupt line to allocate
1579  *      @handler: Function to be called when the IRQ occurs.
1580  *                Threaded handler for threaded interrupts.
1581  *      @flags: Interrupt type flags
1582  *      @name: An ascii name for the claiming device
1583  *      @dev_id: A cookie passed back to the handler function
1584  *
1585  *      This call allocates interrupt resources and enables the
1586  *      interrupt line and IRQ handling. It selects either a
1587  *      hardirq or threaded handling method depending on the
1588  *      context.
1589  *
1590  *      On failure, it returns a negative value. On success,
1591  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1592  */
1593 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1594                             unsigned long flags, const char *name, void *dev_id)
1595 {
1596         struct irq_desc *desc = irq_to_desc(irq);
1597         int ret;
1598 
1599         if (!desc)
1600                 return -EINVAL;
1601 
1602         if (irq_settings_is_nested_thread(desc)) {
1603                 ret = request_threaded_irq(irq, NULL, handler,
1604                                            flags, name, dev_id);
1605                 return !ret ? IRQC_IS_NESTED : ret;
1606         }
1607 
1608         ret = request_irq(irq, handler, flags, name, dev_id);
1609         return !ret ? IRQC_IS_HARDIRQ : ret;
1610 }
1611 EXPORT_SYMBOL_GPL(request_any_context_irq);
1612 
1613 void enable_percpu_irq(unsigned int irq, unsigned int type)
1614 {
1615         unsigned int cpu = smp_processor_id();
1616         unsigned long flags;
1617         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1618 
1619         if (!desc)
1620                 return;
1621 
1622         type &= IRQ_TYPE_SENSE_MASK;
1623         if (type != IRQ_TYPE_NONE) {
1624                 int ret;
1625 
1626                 ret = __irq_set_trigger(desc, irq, type);
1627 
1628                 if (ret) {
1629                         WARN(1, "failed to set type for IRQ%d\n", irq);
1630                         goto out;
1631                 }
1632         }
1633 
1634         irq_percpu_enable(desc, cpu);
1635 out:
1636         irq_put_desc_unlock(desc, flags);
1637 }
1638 EXPORT_SYMBOL_GPL(enable_percpu_irq);
1639 
1640 void disable_percpu_irq(unsigned int irq)
1641 {
1642         unsigned int cpu = smp_processor_id();
1643         unsigned long flags;
1644         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1645 
1646         if (!desc)
1647                 return;
1648 
1649         irq_percpu_disable(desc, cpu);
1650         irq_put_desc_unlock(desc, flags);
1651 }
1652 EXPORT_SYMBOL_GPL(disable_percpu_irq);
1653 
1654 /*
1655  * Internal function to unregister a percpu irqaction.
1656  */
1657 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1658 {
1659         struct irq_desc *desc = irq_to_desc(irq);
1660         struct irqaction *action;
1661         unsigned long flags;
1662 
1663         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1664 
1665         if (!desc)
1666                 return NULL;
1667 
1668         raw_spin_lock_irqsave(&desc->lock, flags);
1669 
1670         action = desc->action;
1671         if (!action || action->percpu_dev_id != dev_id) {
1672                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1673                 goto bad;
1674         }
1675 
1676         if (!cpumask_empty(desc->percpu_enabled)) {
1677                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1678                      irq, cpumask_first(desc->percpu_enabled));
1679                 goto bad;
1680         }
1681 
1682         /* Found it - now remove it from the list of entries: */
1683         desc->action = NULL;
1684 
1685         raw_spin_unlock_irqrestore(&desc->lock, flags);
1686 
1687         unregister_handler_proc(irq, action);
1688 
1689         module_put(desc->owner);
1690         return action;
1691 
1692 bad:
1693         raw_spin_unlock_irqrestore(&desc->lock, flags);
1694         return NULL;
1695 }
1696 
1697 /**
1698  *      remove_percpu_irq - free a per-cpu interrupt
1699  *      @irq: Interrupt line to free
1700  *      @act: irqaction for the interrupt
1701  *
1702  * Used to remove interrupts statically setup by the early boot process.
1703  */
1704 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1705 {
1706         struct irq_desc *desc = irq_to_desc(irq);
1707 
1708         if (desc && irq_settings_is_per_cpu_devid(desc))
1709             __free_percpu_irq(irq, act->percpu_dev_id);
1710 }
1711 
1712 /**
1713  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1714  *      @irq: Interrupt line to free
1715  *      @dev_id: Device identity to free
1716  *
1717  *      Remove a percpu interrupt handler. The handler is removed, but
1718  *      the interrupt line is not disabled. This must be done on each
1719  *      CPU before calling this function. The function does not return
1720  *      until any executing interrupts for this IRQ have completed.
1721  *
1722  *      This function must not be called from interrupt context.
1723  */
1724 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1725 {
1726         struct irq_desc *desc = irq_to_desc(irq);
1727 
1728         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1729                 return;
1730 
1731         chip_bus_lock(desc);
1732         kfree(__free_percpu_irq(irq, dev_id));
1733         chip_bus_sync_unlock(desc);
1734 }
1735 
1736 /**
1737  *      setup_percpu_irq - setup a per-cpu interrupt
1738  *      @irq: Interrupt line to setup
1739  *      @act: irqaction for the interrupt
1740  *
1741  * Used to statically setup per-cpu interrupts in the early boot process.
1742  */
1743 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1744 {
1745         struct irq_desc *desc = irq_to_desc(irq);
1746         int retval;
1747 
1748         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1749                 return -EINVAL;
1750         chip_bus_lock(desc);
1751         retval = __setup_irq(irq, desc, act);
1752         chip_bus_sync_unlock(desc);
1753 
1754         return retval;
1755 }
1756 
1757 /**
1758  *      request_percpu_irq - allocate a percpu interrupt line
1759  *      @irq: Interrupt line to allocate
1760  *      @handler: Function to be called when the IRQ occurs.
1761  *      @devname: An ascii name for the claiming device
1762  *      @dev_id: A percpu cookie passed back to the handler function
1763  *
1764  *      This call allocates interrupt resources, but doesn't
1765  *      automatically enable the interrupt. It has to be done on each
1766  *      CPU using enable_percpu_irq().
1767  *
1768  *      Dev_id must be globally unique. It is a per-cpu variable, and
1769  *      the handler gets called with the interrupted CPU's instance of
1770  *      that variable.
1771  */
1772 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1773                        const char *devname, void __percpu *dev_id)
1774 {
1775         struct irqaction *action;
1776         struct irq_desc *desc;
1777         int retval;
1778 
1779         if (!dev_id)
1780                 return -EINVAL;
1781 
1782         desc = irq_to_desc(irq);
1783         if (!desc || !irq_settings_can_request(desc) ||
1784             !irq_settings_is_per_cpu_devid(desc))
1785                 return -EINVAL;
1786 
1787         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1788         if (!action)
1789                 return -ENOMEM;
1790 
1791         action->handler = handler;
1792         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1793         action->name = devname;
1794         action->percpu_dev_id = dev_id;
1795 
1796         chip_bus_lock(desc);
1797         retval = __setup_irq(irq, desc, action);
1798         chip_bus_sync_unlock(desc);
1799 
1800         if (retval)
1801                 kfree(action);
1802 
1803         return retval;
1804 }
1805 
1806 /**
1807  *      irq_get_irqchip_state - returns the irqchip state of a interrupt.
1808  *      @irq: Interrupt line that is forwarded to a VM
1809  *      @which: One of IRQCHIP_STATE_* the caller wants to know about
1810  *      @state: a pointer to a boolean where the state is to be storeed
1811  *
1812  *      This call snapshots the internal irqchip state of an
1813  *      interrupt, returning into @state the bit corresponding to
1814  *      stage @which
1815  *
1816  *      This function should be called with preemption disabled if the
1817  *      interrupt controller has per-cpu registers.
1818  */
1819 int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
1820                           bool *state)
1821 {
1822         struct irq_desc *desc;
1823         struct irq_data *data;
1824         struct irq_chip *chip;
1825         unsigned long flags;
1826         int err = -EINVAL;
1827 
1828         desc = irq_get_desc_buslock(irq, &flags, 0);
1829         if (!desc)
1830                 return err;
1831 
1832         data = irq_desc_get_irq_data(desc);
1833 
1834         do {
1835                 chip = irq_data_get_irq_chip(data);
1836                 if (chip->irq_get_irqchip_state)
1837                         break;
1838 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
1839                 data = data->parent_data;
1840 #else
1841                 data = NULL;
1842 #endif
1843         } while (data);
1844 
1845         if (data)
1846                 err = chip->irq_get_irqchip_state(data, which, state);
1847 
1848         irq_put_desc_busunlock(desc, flags);
1849         return err;
1850 }
1851 
1852 /**
1853  *      irq_set_irqchip_state - set the state of a forwarded interrupt.
1854  *      @irq: Interrupt line that is forwarded to a VM
1855  *      @which: State to be restored (one of IRQCHIP_STATE_*)
1856  *      @val: Value corresponding to @which
1857  *
1858  *      This call sets the internal irqchip state of an interrupt,
1859  *      depending on the value of @which.
1860  *
1861  *      This function should be called with preemption disabled if the
1862  *      interrupt controller has per-cpu registers.
1863  */
1864 int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
1865                           bool val)
1866 {
1867         struct irq_desc *desc;
1868         struct irq_data *data;
1869         struct irq_chip *chip;
1870         unsigned long flags;
1871         int err = -EINVAL;
1872 
1873         desc = irq_get_desc_buslock(irq, &flags, 0);
1874         if (!desc)
1875                 return err;
1876 
1877         data = irq_desc_get_irq_data(desc);
1878 
1879         do {
1880                 chip = irq_data_get_irq_chip(data);
1881                 if (chip->irq_set_irqchip_state)
1882                         break;
1883 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
1884                 data = data->parent_data;
1885 #else
1886                 data = NULL;
1887 #endif
1888         } while (data);
1889 
1890         if (data)
1891                 err = chip->irq_set_irqchip_state(data, which, val);
1892 
1893         irq_put_desc_busunlock(desc, flags);
1894         return err;
1895 }
1896 

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