keys: kill task_struct->replacement_session_keyring
[linux-3.10.git] / kernel / irq / manage.c
1 /*
2  * linux/kernel/irq/manage.c
3  *
4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5  * Copyright (C) 2005-2006 Thomas Gleixner
6  *
7  * This file contains driver APIs to the irq subsystem.
8  */
9
10 #include <linux/irq.h>
11 #include <linux/kthread.h>
12 #include <linux/module.h>
13 #include <linux/random.h>
14 #include <linux/interrupt.h>
15 #include <linux/slab.h>
16 #include <linux/sched.h>
17 #include <linux/task_work.h>
18
19 #include "internals.h"
20
21 #ifdef CONFIG_IRQ_FORCED_THREADING
22 __read_mostly bool force_irqthreads;
23
24 static int __init setup_forced_irqthreads(char *arg)
25 {
26         force_irqthreads = true;
27         return 0;
28 }
29 early_param("threadirqs", setup_forced_irqthreads);
30 #endif
31
32 /**
33  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
34  *      @irq: interrupt number to wait for
35  *
36  *      This function waits for any pending IRQ handlers for this interrupt
37  *      to complete before returning. If you use this function while
38  *      holding a resource the IRQ handler may need you will deadlock.
39  *
40  *      This function may be called - with care - from IRQ context.
41  */
42 void synchronize_irq(unsigned int irq)
43 {
44         struct irq_desc *desc = irq_to_desc(irq);
45         bool inprogress;
46
47         if (!desc)
48                 return;
49
50         do {
51                 unsigned long flags;
52
53                 /*
54                  * Wait until we're out of the critical section.  This might
55                  * give the wrong answer due to the lack of memory barriers.
56                  */
57                 while (irqd_irq_inprogress(&desc->irq_data))
58                         cpu_relax();
59
60                 /* Ok, that indicated we're done: double-check carefully. */
61                 raw_spin_lock_irqsave(&desc->lock, flags);
62                 inprogress = irqd_irq_inprogress(&desc->irq_data);
63                 raw_spin_unlock_irqrestore(&desc->lock, flags);
64
65                 /* Oops, that failed? */
66         } while (inprogress);
67
68         /*
69          * We made sure that no hardirq handler is running. Now verify
70          * that no threaded handlers are active.
71          */
72         wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
73 }
74 EXPORT_SYMBOL(synchronize_irq);
75
76 #ifdef CONFIG_SMP
77 cpumask_var_t irq_default_affinity;
78
79 /**
80  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
81  *      @irq:           Interrupt to check
82  *
83  */
84 int irq_can_set_affinity(unsigned int irq)
85 {
86         struct irq_desc *desc = irq_to_desc(irq);
87
88         if (!desc || !irqd_can_balance(&desc->irq_data) ||
89             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
90                 return 0;
91
92         return 1;
93 }
94
95 /**
96  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
97  *      @desc:          irq descriptor which has affitnity changed
98  *
99  *      We just set IRQTF_AFFINITY and delegate the affinity setting
100  *      to the interrupt thread itself. We can not call
101  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
102  *      code can be called from hard interrupt context.
103  */
104 void irq_set_thread_affinity(struct irq_desc *desc)
105 {
106         struct irqaction *action = desc->action;
107
108         while (action) {
109                 if (action->thread)
110                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
111                 action = action->next;
112         }
113 }
114
115 #ifdef CONFIG_GENERIC_PENDING_IRQ
116 static inline bool irq_can_move_pcntxt(struct irq_data *data)
117 {
118         return irqd_can_move_in_process_context(data);
119 }
120 static inline bool irq_move_pending(struct irq_data *data)
121 {
122         return irqd_is_setaffinity_pending(data);
123 }
124 static inline void
125 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
126 {
127         cpumask_copy(desc->pending_mask, mask);
128 }
129 static inline void
130 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
131 {
132         cpumask_copy(mask, desc->pending_mask);
133 }
134 #else
135 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
136 static inline bool irq_move_pending(struct irq_data *data) { return false; }
137 static inline void
138 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
139 static inline void
140 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
141 #endif
142
143 int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
144 {
145         struct irq_chip *chip = irq_data_get_irq_chip(data);
146         struct irq_desc *desc = irq_data_to_desc(data);
147         int ret = 0;
148
149         if (!chip || !chip->irq_set_affinity)
150                 return -EINVAL;
151
152         if (irq_can_move_pcntxt(data)) {
153                 ret = chip->irq_set_affinity(data, mask, false);
154                 switch (ret) {
155                 case IRQ_SET_MASK_OK:
156                         cpumask_copy(data->affinity, mask);
157                 case IRQ_SET_MASK_OK_NOCOPY:
158                         irq_set_thread_affinity(desc);
159                         ret = 0;
160                 }
161         } else {
162                 irqd_set_move_pending(data);
163                 irq_copy_pending(desc, mask);
164         }
165
166         if (desc->affinity_notify) {
167                 kref_get(&desc->affinity_notify->kref);
168                 schedule_work(&desc->affinity_notify->work);
169         }
170         irqd_set(data, IRQD_AFFINITY_SET);
171
172         return ret;
173 }
174
175 /**
176  *      irq_set_affinity - Set the irq affinity of a given irq
177  *      @irq:           Interrupt to set affinity
178  *      @mask:          cpumask
179  *
180  */
181 int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
182 {
183         struct irq_desc *desc = irq_to_desc(irq);
184         unsigned long flags;
185         int ret;
186
187         if (!desc)
188                 return -EINVAL;
189
190         raw_spin_lock_irqsave(&desc->lock, flags);
191         ret =  __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
192         raw_spin_unlock_irqrestore(&desc->lock, flags);
193         return ret;
194 }
195
196 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
197 {
198         unsigned long flags;
199         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
200
201         if (!desc)
202                 return -EINVAL;
203         desc->affinity_hint = m;
204         irq_put_desc_unlock(desc, flags);
205         return 0;
206 }
207 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
208
209 static void irq_affinity_notify(struct work_struct *work)
210 {
211         struct irq_affinity_notify *notify =
212                 container_of(work, struct irq_affinity_notify, work);
213         struct irq_desc *desc = irq_to_desc(notify->irq);
214         cpumask_var_t cpumask;
215         unsigned long flags;
216
217         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
218                 goto out;
219
220         raw_spin_lock_irqsave(&desc->lock, flags);
221         if (irq_move_pending(&desc->irq_data))
222                 irq_get_pending(cpumask, desc);
223         else
224                 cpumask_copy(cpumask, desc->irq_data.affinity);
225         raw_spin_unlock_irqrestore(&desc->lock, flags);
226
227         notify->notify(notify, cpumask);
228
229         free_cpumask_var(cpumask);
230 out:
231         kref_put(&notify->kref, notify->release);
232 }
233
234 /**
235  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
236  *      @irq:           Interrupt for which to enable/disable notification
237  *      @notify:        Context for notification, or %NULL to disable
238  *                      notification.  Function pointers must be initialised;
239  *                      the other fields will be initialised by this function.
240  *
241  *      Must be called in process context.  Notification may only be enabled
242  *      after the IRQ is allocated and must be disabled before the IRQ is
243  *      freed using free_irq().
244  */
245 int
246 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
247 {
248         struct irq_desc *desc = irq_to_desc(irq);
249         struct irq_affinity_notify *old_notify;
250         unsigned long flags;
251
252         /* The release function is promised process context */
253         might_sleep();
254
255         if (!desc)
256                 return -EINVAL;
257
258         /* Complete initialisation of *notify */
259         if (notify) {
260                 notify->irq = irq;
261                 kref_init(&notify->kref);
262                 INIT_WORK(&notify->work, irq_affinity_notify);
263         }
264
265         raw_spin_lock_irqsave(&desc->lock, flags);
266         old_notify = desc->affinity_notify;
267         desc->affinity_notify = notify;
268         raw_spin_unlock_irqrestore(&desc->lock, flags);
269
270         if (old_notify)
271                 kref_put(&old_notify->kref, old_notify->release);
272
273         return 0;
274 }
275 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
276
277 #ifndef CONFIG_AUTO_IRQ_AFFINITY
278 /*
279  * Generic version of the affinity autoselector.
280  */
281 static int
282 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
283 {
284         struct irq_chip *chip = irq_desc_get_chip(desc);
285         struct cpumask *set = irq_default_affinity;
286         int ret, node = desc->irq_data.node;
287
288         /* Excludes PER_CPU and NO_BALANCE interrupts */
289         if (!irq_can_set_affinity(irq))
290                 return 0;
291
292         /*
293          * Preserve an userspace affinity setup, but make sure that
294          * one of the targets is online.
295          */
296         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
297                 if (cpumask_intersects(desc->irq_data.affinity,
298                                        cpu_online_mask))
299                         set = desc->irq_data.affinity;
300                 else
301                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
302         }
303
304         cpumask_and(mask, cpu_online_mask, set);
305         if (node != NUMA_NO_NODE) {
306                 const struct cpumask *nodemask = cpumask_of_node(node);
307
308                 /* make sure at least one of the cpus in nodemask is online */
309                 if (cpumask_intersects(mask, nodemask))
310                         cpumask_and(mask, mask, nodemask);
311         }
312         ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
313         switch (ret) {
314         case IRQ_SET_MASK_OK:
315                 cpumask_copy(desc->irq_data.affinity, mask);
316         case IRQ_SET_MASK_OK_NOCOPY:
317                 irq_set_thread_affinity(desc);
318         }
319         return 0;
320 }
321 #else
322 static inline int
323 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
324 {
325         return irq_select_affinity(irq);
326 }
327 #endif
328
329 /*
330  * Called when affinity is set via /proc/irq
331  */
332 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
333 {
334         struct irq_desc *desc = irq_to_desc(irq);
335         unsigned long flags;
336         int ret;
337
338         raw_spin_lock_irqsave(&desc->lock, flags);
339         ret = setup_affinity(irq, desc, mask);
340         raw_spin_unlock_irqrestore(&desc->lock, flags);
341         return ret;
342 }
343
344 #else
345 static inline int
346 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
347 {
348         return 0;
349 }
350 #endif
351
352 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
353 {
354         if (suspend) {
355                 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
356                         return;
357                 desc->istate |= IRQS_SUSPENDED;
358         }
359
360         if (!desc->depth++)
361                 irq_disable(desc);
362 }
363
364 static int __disable_irq_nosync(unsigned int irq)
365 {
366         unsigned long flags;
367         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
368
369         if (!desc)
370                 return -EINVAL;
371         __disable_irq(desc, irq, false);
372         irq_put_desc_busunlock(desc, flags);
373         return 0;
374 }
375
376 /**
377  *      disable_irq_nosync - disable an irq without waiting
378  *      @irq: Interrupt to disable
379  *
380  *      Disable the selected interrupt line.  Disables and Enables are
381  *      nested.
382  *      Unlike disable_irq(), this function does not ensure existing
383  *      instances of the IRQ handler have completed before returning.
384  *
385  *      This function may be called from IRQ context.
386  */
387 void disable_irq_nosync(unsigned int irq)
388 {
389         __disable_irq_nosync(irq);
390 }
391 EXPORT_SYMBOL(disable_irq_nosync);
392
393 /**
394  *      disable_irq - disable an irq and wait for completion
395  *      @irq: Interrupt to disable
396  *
397  *      Disable the selected interrupt line.  Enables and Disables are
398  *      nested.
399  *      This function waits for any pending IRQ handlers for this interrupt
400  *      to complete before returning. If you use this function while
401  *      holding a resource the IRQ handler may need you will deadlock.
402  *
403  *      This function may be called - with care - from IRQ context.
404  */
405 void disable_irq(unsigned int irq)
406 {
407         if (!__disable_irq_nosync(irq))
408                 synchronize_irq(irq);
409 }
410 EXPORT_SYMBOL(disable_irq);
411
412 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
413 {
414         if (resume) {
415                 if (!(desc->istate & IRQS_SUSPENDED)) {
416                         if (!desc->action)
417                                 return;
418                         if (!(desc->action->flags & IRQF_FORCE_RESUME))
419                                 return;
420                         /* Pretend that it got disabled ! */
421                         desc->depth++;
422                 }
423                 desc->istate &= ~IRQS_SUSPENDED;
424         }
425
426         switch (desc->depth) {
427         case 0:
428  err_out:
429                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
430                 break;
431         case 1: {
432                 if (desc->istate & IRQS_SUSPENDED)
433                         goto err_out;
434                 /* Prevent probing on this irq: */
435                 irq_settings_set_noprobe(desc);
436                 irq_enable(desc);
437                 check_irq_resend(desc, irq);
438                 /* fall-through */
439         }
440         default:
441                 desc->depth--;
442         }
443 }
444
445 /**
446  *      enable_irq - enable handling of an irq
447  *      @irq: Interrupt to enable
448  *
449  *      Undoes the effect of one call to disable_irq().  If this
450  *      matches the last disable, processing of interrupts on this
451  *      IRQ line is re-enabled.
452  *
453  *      This function may be called from IRQ context only when
454  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
455  */
456 void enable_irq(unsigned int irq)
457 {
458         unsigned long flags;
459         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
460
461         if (!desc)
462                 return;
463         if (WARN(!desc->irq_data.chip,
464                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
465                 goto out;
466
467         __enable_irq(desc, irq, false);
468 out:
469         irq_put_desc_busunlock(desc, flags);
470 }
471 EXPORT_SYMBOL(enable_irq);
472
473 static int set_irq_wake_real(unsigned int irq, unsigned int on)
474 {
475         struct irq_desc *desc = irq_to_desc(irq);
476         int ret = -ENXIO;
477
478         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
479                 return 0;
480
481         if (desc->irq_data.chip->irq_set_wake)
482                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
483
484         return ret;
485 }
486
487 /**
488  *      irq_set_irq_wake - control irq power management wakeup
489  *      @irq:   interrupt to control
490  *      @on:    enable/disable power management wakeup
491  *
492  *      Enable/disable power management wakeup mode, which is
493  *      disabled by default.  Enables and disables must match,
494  *      just as they match for non-wakeup mode support.
495  *
496  *      Wakeup mode lets this IRQ wake the system from sleep
497  *      states like "suspend to RAM".
498  */
499 int irq_set_irq_wake(unsigned int irq, unsigned int on)
500 {
501         unsigned long flags;
502         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
503         int ret = 0;
504
505         if (!desc)
506                 return -EINVAL;
507
508         /* wakeup-capable irqs can be shared between drivers that
509          * don't need to have the same sleep mode behaviors.
510          */
511         if (on) {
512                 if (desc->wake_depth++ == 0) {
513                         ret = set_irq_wake_real(irq, on);
514                         if (ret)
515                                 desc->wake_depth = 0;
516                         else
517                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
518                 }
519         } else {
520                 if (desc->wake_depth == 0) {
521                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
522                 } else if (--desc->wake_depth == 0) {
523                         ret = set_irq_wake_real(irq, on);
524                         if (ret)
525                                 desc->wake_depth = 1;
526                         else
527                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
528                 }
529         }
530         irq_put_desc_busunlock(desc, flags);
531         return ret;
532 }
533 EXPORT_SYMBOL(irq_set_irq_wake);
534
535 /*
536  * Internal function that tells the architecture code whether a
537  * particular irq has been exclusively allocated or is available
538  * for driver use.
539  */
540 int can_request_irq(unsigned int irq, unsigned long irqflags)
541 {
542         unsigned long flags;
543         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
544         int canrequest = 0;
545
546         if (!desc)
547                 return 0;
548
549         if (irq_settings_can_request(desc)) {
550                 if (desc->action)
551                         if (irqflags & desc->action->flags & IRQF_SHARED)
552                                 canrequest =1;
553         }
554         irq_put_desc_unlock(desc, flags);
555         return canrequest;
556 }
557
558 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
559                       unsigned long flags)
560 {
561         struct irq_chip *chip = desc->irq_data.chip;
562         int ret, unmask = 0;
563
564         if (!chip || !chip->irq_set_type) {
565                 /*
566                  * IRQF_TRIGGER_* but the PIC does not support multiple
567                  * flow-types?
568                  */
569                 pr_debug("genirq: No set_type function for IRQ %d (%s)\n", irq,
570                          chip ? (chip->name ? : "unknown") : "unknown");
571                 return 0;
572         }
573
574         flags &= IRQ_TYPE_SENSE_MASK;
575
576         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
577                 if (!irqd_irq_masked(&desc->irq_data))
578                         mask_irq(desc);
579                 if (!irqd_irq_disabled(&desc->irq_data))
580                         unmask = 1;
581         }
582
583         /* caller masked out all except trigger mode flags */
584         ret = chip->irq_set_type(&desc->irq_data, flags);
585
586         switch (ret) {
587         case IRQ_SET_MASK_OK:
588                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
589                 irqd_set(&desc->irq_data, flags);
590
591         case IRQ_SET_MASK_OK_NOCOPY:
592                 flags = irqd_get_trigger_type(&desc->irq_data);
593                 irq_settings_set_trigger_mask(desc, flags);
594                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
595                 irq_settings_clr_level(desc);
596                 if (flags & IRQ_TYPE_LEVEL_MASK) {
597                         irq_settings_set_level(desc);
598                         irqd_set(&desc->irq_data, IRQD_LEVEL);
599                 }
600
601                 ret = 0;
602                 break;
603         default:
604                 pr_err("genirq: Setting trigger mode %lu for irq %u failed (%pF)\n",
605                        flags, irq, chip->irq_set_type);
606         }
607         if (unmask)
608                 unmask_irq(desc);
609         return ret;
610 }
611
612 /*
613  * Default primary interrupt handler for threaded interrupts. Is
614  * assigned as primary handler when request_threaded_irq is called
615  * with handler == NULL. Useful for oneshot interrupts.
616  */
617 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
618 {
619         return IRQ_WAKE_THREAD;
620 }
621
622 /*
623  * Primary handler for nested threaded interrupts. Should never be
624  * called.
625  */
626 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
627 {
628         WARN(1, "Primary handler called for nested irq %d\n", irq);
629         return IRQ_NONE;
630 }
631
632 static int irq_wait_for_interrupt(struct irqaction *action)
633 {
634         set_current_state(TASK_INTERRUPTIBLE);
635
636         while (!kthread_should_stop()) {
637
638                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
639                                        &action->thread_flags)) {
640                         __set_current_state(TASK_RUNNING);
641                         return 0;
642                 }
643                 schedule();
644                 set_current_state(TASK_INTERRUPTIBLE);
645         }
646         __set_current_state(TASK_RUNNING);
647         return -1;
648 }
649
650 /*
651  * Oneshot interrupts keep the irq line masked until the threaded
652  * handler finished. unmask if the interrupt has not been disabled and
653  * is marked MASKED.
654  */
655 static void irq_finalize_oneshot(struct irq_desc *desc,
656                                  struct irqaction *action)
657 {
658         if (!(desc->istate & IRQS_ONESHOT))
659                 return;
660 again:
661         chip_bus_lock(desc);
662         raw_spin_lock_irq(&desc->lock);
663
664         /*
665          * Implausible though it may be we need to protect us against
666          * the following scenario:
667          *
668          * The thread is faster done than the hard interrupt handler
669          * on the other CPU. If we unmask the irq line then the
670          * interrupt can come in again and masks the line, leaves due
671          * to IRQS_INPROGRESS and the irq line is masked forever.
672          *
673          * This also serializes the state of shared oneshot handlers
674          * versus "desc->threads_onehsot |= action->thread_mask;" in
675          * irq_wake_thread(). See the comment there which explains the
676          * serialization.
677          */
678         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
679                 raw_spin_unlock_irq(&desc->lock);
680                 chip_bus_sync_unlock(desc);
681                 cpu_relax();
682                 goto again;
683         }
684
685         /*
686          * Now check again, whether the thread should run. Otherwise
687          * we would clear the threads_oneshot bit of this thread which
688          * was just set.
689          */
690         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
691                 goto out_unlock;
692
693         desc->threads_oneshot &= ~action->thread_mask;
694
695         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
696             irqd_irq_masked(&desc->irq_data))
697                 unmask_irq(desc);
698
699 out_unlock:
700         raw_spin_unlock_irq(&desc->lock);
701         chip_bus_sync_unlock(desc);
702 }
703
704 #ifdef CONFIG_SMP
705 /*
706  * Check whether we need to chasnge the affinity of the interrupt thread.
707  */
708 static void
709 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
710 {
711         cpumask_var_t mask;
712
713         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
714                 return;
715
716         /*
717          * In case we are out of memory we set IRQTF_AFFINITY again and
718          * try again next time
719          */
720         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
721                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
722                 return;
723         }
724
725         raw_spin_lock_irq(&desc->lock);
726         cpumask_copy(mask, desc->irq_data.affinity);
727         raw_spin_unlock_irq(&desc->lock);
728
729         set_cpus_allowed_ptr(current, mask);
730         free_cpumask_var(mask);
731 }
732 #else
733 static inline void
734 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
735 #endif
736
737 /*
738  * Interrupts which are not explicitely requested as threaded
739  * interrupts rely on the implicit bh/preempt disable of the hard irq
740  * context. So we need to disable bh here to avoid deadlocks and other
741  * side effects.
742  */
743 static irqreturn_t
744 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
745 {
746         irqreturn_t ret;
747
748         local_bh_disable();
749         ret = action->thread_fn(action->irq, action->dev_id);
750         irq_finalize_oneshot(desc, action);
751         local_bh_enable();
752         return ret;
753 }
754
755 /*
756  * Interrupts explicitely requested as threaded interupts want to be
757  * preemtible - many of them need to sleep and wait for slow busses to
758  * complete.
759  */
760 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
761                 struct irqaction *action)
762 {
763         irqreturn_t ret;
764
765         ret = action->thread_fn(action->irq, action->dev_id);
766         irq_finalize_oneshot(desc, action);
767         return ret;
768 }
769
770 static void wake_threads_waitq(struct irq_desc *desc)
771 {
772         if (atomic_dec_and_test(&desc->threads_active) &&
773             waitqueue_active(&desc->wait_for_threads))
774                 wake_up(&desc->wait_for_threads);
775 }
776
777 static void irq_thread_dtor(struct task_work *unused)
778 {
779         struct task_struct *tsk = current;
780         struct irq_desc *desc;
781         struct irqaction *action;
782
783         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
784                 return;
785
786         action = kthread_data(tsk);
787
788         pr_err("genirq: exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
789                tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
790
791
792         desc = irq_to_desc(action->irq);
793         /*
794          * If IRQTF_RUNTHREAD is set, we need to decrement
795          * desc->threads_active and wake possible waiters.
796          */
797         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
798                 wake_threads_waitq(desc);
799
800         /* Prevent a stale desc->threads_oneshot */
801         irq_finalize_oneshot(desc, action);
802 }
803
804 /*
805  * Interrupt handler thread
806  */
807 static int irq_thread(void *data)
808 {
809         struct task_work on_exit_work;
810         static const struct sched_param param = {
811                 .sched_priority = MAX_USER_RT_PRIO/2,
812         };
813         struct irqaction *action = data;
814         struct irq_desc *desc = irq_to_desc(action->irq);
815         irqreturn_t (*handler_fn)(struct irq_desc *desc,
816                         struct irqaction *action);
817
818         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
819                                         &action->thread_flags))
820                 handler_fn = irq_forced_thread_fn;
821         else
822                 handler_fn = irq_thread_fn;
823
824         sched_setscheduler(current, SCHED_FIFO, &param);
825
826         init_task_work(&on_exit_work, irq_thread_dtor, NULL);
827         task_work_add(current, &on_exit_work, false);
828
829         while (!irq_wait_for_interrupt(action)) {
830                 irqreturn_t action_ret;
831
832                 irq_thread_check_affinity(desc, action);
833
834                 action_ret = handler_fn(desc, action);
835                 if (!noirqdebug)
836                         note_interrupt(action->irq, desc, action_ret);
837
838                 wake_threads_waitq(desc);
839         }
840
841         /*
842          * This is the regular exit path. __free_irq() is stopping the
843          * thread via kthread_stop() after calling
844          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
845          * oneshot mask bit can be set. We cannot verify that as we
846          * cannot touch the oneshot mask at this point anymore as
847          * __setup_irq() might have given out currents thread_mask
848          * again.
849          */
850         task_work_cancel(current, irq_thread_dtor);
851         return 0;
852 }
853
854 static void irq_setup_forced_threading(struct irqaction *new)
855 {
856         if (!force_irqthreads)
857                 return;
858         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
859                 return;
860
861         new->flags |= IRQF_ONESHOT;
862
863         if (!new->thread_fn) {
864                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
865                 new->thread_fn = new->handler;
866                 new->handler = irq_default_primary_handler;
867         }
868 }
869
870 /*
871  * Internal function to register an irqaction - typically used to
872  * allocate special interrupts that are part of the architecture.
873  */
874 static int
875 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
876 {
877         struct irqaction *old, **old_ptr;
878         unsigned long flags, thread_mask = 0;
879         int ret, nested, shared = 0;
880         cpumask_var_t mask;
881
882         if (!desc)
883                 return -EINVAL;
884
885         if (desc->irq_data.chip == &no_irq_chip)
886                 return -ENOSYS;
887         if (!try_module_get(desc->owner))
888                 return -ENODEV;
889         /*
890          * Some drivers like serial.c use request_irq() heavily,
891          * so we have to be careful not to interfere with a
892          * running system.
893          */
894         if (new->flags & IRQF_SAMPLE_RANDOM) {
895                 /*
896                  * This function might sleep, we want to call it first,
897                  * outside of the atomic block.
898                  * Yes, this might clear the entropy pool if the wrong
899                  * driver is attempted to be loaded, without actually
900                  * installing a new handler, but is this really a problem,
901                  * only the sysadmin is able to do this.
902                  */
903                 rand_initialize_irq(irq);
904         }
905
906         /*
907          * Check whether the interrupt nests into another interrupt
908          * thread.
909          */
910         nested = irq_settings_is_nested_thread(desc);
911         if (nested) {
912                 if (!new->thread_fn) {
913                         ret = -EINVAL;
914                         goto out_mput;
915                 }
916                 /*
917                  * Replace the primary handler which was provided from
918                  * the driver for non nested interrupt handling by the
919                  * dummy function which warns when called.
920                  */
921                 new->handler = irq_nested_primary_handler;
922         } else {
923                 if (irq_settings_can_thread(desc))
924                         irq_setup_forced_threading(new);
925         }
926
927         /*
928          * Create a handler thread when a thread function is supplied
929          * and the interrupt does not nest into another interrupt
930          * thread.
931          */
932         if (new->thread_fn && !nested) {
933                 struct task_struct *t;
934
935                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
936                                    new->name);
937                 if (IS_ERR(t)) {
938                         ret = PTR_ERR(t);
939                         goto out_mput;
940                 }
941                 /*
942                  * We keep the reference to the task struct even if
943                  * the thread dies to avoid that the interrupt code
944                  * references an already freed task_struct.
945                  */
946                 get_task_struct(t);
947                 new->thread = t;
948         }
949
950         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
951                 ret = -ENOMEM;
952                 goto out_thread;
953         }
954
955         /*
956          * The following block of code has to be executed atomically
957          */
958         raw_spin_lock_irqsave(&desc->lock, flags);
959         old_ptr = &desc->action;
960         old = *old_ptr;
961         if (old) {
962                 /*
963                  * Can't share interrupts unless both agree to and are
964                  * the same type (level, edge, polarity). So both flag
965                  * fields must have IRQF_SHARED set and the bits which
966                  * set the trigger type must match. Also all must
967                  * agree on ONESHOT.
968                  */
969                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
970                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
971                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
972                         goto mismatch;
973
974                 /* All handlers must agree on per-cpuness */
975                 if ((old->flags & IRQF_PERCPU) !=
976                     (new->flags & IRQF_PERCPU))
977                         goto mismatch;
978
979                 /* add new interrupt at end of irq queue */
980                 do {
981                         /*
982                          * Or all existing action->thread_mask bits,
983                          * so we can find the next zero bit for this
984                          * new action.
985                          */
986                         thread_mask |= old->thread_mask;
987                         old_ptr = &old->next;
988                         old = *old_ptr;
989                 } while (old);
990                 shared = 1;
991         }
992
993         /*
994          * Setup the thread mask for this irqaction for ONESHOT. For
995          * !ONESHOT irqs the thread mask is 0 so we can avoid a
996          * conditional in irq_wake_thread().
997          */
998         if (new->flags & IRQF_ONESHOT) {
999                 /*
1000                  * Unlikely to have 32 resp 64 irqs sharing one line,
1001                  * but who knows.
1002                  */
1003                 if (thread_mask == ~0UL) {
1004                         ret = -EBUSY;
1005                         goto out_mask;
1006                 }
1007                 /*
1008                  * The thread_mask for the action is or'ed to
1009                  * desc->thread_active to indicate that the
1010                  * IRQF_ONESHOT thread handler has been woken, but not
1011                  * yet finished. The bit is cleared when a thread
1012                  * completes. When all threads of a shared interrupt
1013                  * line have completed desc->threads_active becomes
1014                  * zero and the interrupt line is unmasked. See
1015                  * handle.c:irq_wake_thread() for further information.
1016                  *
1017                  * If no thread is woken by primary (hard irq context)
1018                  * interrupt handlers, then desc->threads_active is
1019                  * also checked for zero to unmask the irq line in the
1020                  * affected hard irq flow handlers
1021                  * (handle_[fasteoi|level]_irq).
1022                  *
1023                  * The new action gets the first zero bit of
1024                  * thread_mask assigned. See the loop above which or's
1025                  * all existing action->thread_mask bits.
1026                  */
1027                 new->thread_mask = 1 << ffz(thread_mask);
1028
1029         } else if (new->handler == irq_default_primary_handler) {
1030                 /*
1031                  * The interrupt was requested with handler = NULL, so
1032                  * we use the default primary handler for it. But it
1033                  * does not have the oneshot flag set. In combination
1034                  * with level interrupts this is deadly, because the
1035                  * default primary handler just wakes the thread, then
1036                  * the irq lines is reenabled, but the device still
1037                  * has the level irq asserted. Rinse and repeat....
1038                  *
1039                  * While this works for edge type interrupts, we play
1040                  * it safe and reject unconditionally because we can't
1041                  * say for sure which type this interrupt really
1042                  * has. The type flags are unreliable as the
1043                  * underlying chip implementation can override them.
1044                  */
1045                 pr_err("genirq: Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1046                        irq);
1047                 ret = -EINVAL;
1048                 goto out_mask;
1049         }
1050
1051         if (!shared) {
1052                 init_waitqueue_head(&desc->wait_for_threads);
1053
1054                 /* Setup the type (level, edge polarity) if configured: */
1055                 if (new->flags & IRQF_TRIGGER_MASK) {
1056                         ret = __irq_set_trigger(desc, irq,
1057                                         new->flags & IRQF_TRIGGER_MASK);
1058
1059                         if (ret)
1060                                 goto out_mask;
1061                 }
1062
1063                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1064                                   IRQS_ONESHOT | IRQS_WAITING);
1065                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1066
1067                 if (new->flags & IRQF_PERCPU) {
1068                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1069                         irq_settings_set_per_cpu(desc);
1070                 }
1071
1072                 if (new->flags & IRQF_ONESHOT)
1073                         desc->istate |= IRQS_ONESHOT;
1074
1075                 if (irq_settings_can_autoenable(desc))
1076                         irq_startup(desc, true);
1077                 else
1078                         /* Undo nested disables: */
1079                         desc->depth = 1;
1080
1081                 /* Exclude IRQ from balancing if requested */
1082                 if (new->flags & IRQF_NOBALANCING) {
1083                         irq_settings_set_no_balancing(desc);
1084                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1085                 }
1086
1087                 /* Set default affinity mask once everything is setup */
1088                 setup_affinity(irq, desc, mask);
1089
1090         } else if (new->flags & IRQF_TRIGGER_MASK) {
1091                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1092                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1093
1094                 if (nmsk != omsk)
1095                         /* hope the handler works with current  trigger mode */
1096                         pr_warning("genirq: irq %d uses trigger mode %u; requested %u\n",
1097                                    irq, nmsk, omsk);
1098         }
1099
1100         new->irq = irq;
1101         *old_ptr = new;
1102
1103         /* Reset broken irq detection when installing new handler */
1104         desc->irq_count = 0;
1105         desc->irqs_unhandled = 0;
1106
1107         /*
1108          * Check whether we disabled the irq via the spurious handler
1109          * before. Reenable it and give it another chance.
1110          */
1111         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1112                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1113                 __enable_irq(desc, irq, false);
1114         }
1115
1116         raw_spin_unlock_irqrestore(&desc->lock, flags);
1117
1118         /*
1119          * Strictly no need to wake it up, but hung_task complains
1120          * when no hard interrupt wakes the thread up.
1121          */
1122         if (new->thread)
1123                 wake_up_process(new->thread);
1124
1125         register_irq_proc(irq, desc);
1126         new->dir = NULL;
1127         register_handler_proc(irq, new);
1128         free_cpumask_var(mask);
1129
1130         return 0;
1131
1132 mismatch:
1133         if (!(new->flags & IRQF_PROBE_SHARED)) {
1134                 pr_err("genirq: Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1135                        irq, new->flags, new->name, old->flags, old->name);
1136 #ifdef CONFIG_DEBUG_SHIRQ
1137                 dump_stack();
1138 #endif
1139         }
1140         ret = -EBUSY;
1141
1142 out_mask:
1143         raw_spin_unlock_irqrestore(&desc->lock, flags);
1144         free_cpumask_var(mask);
1145
1146 out_thread:
1147         if (new->thread) {
1148                 struct task_struct *t = new->thread;
1149
1150                 new->thread = NULL;
1151                 kthread_stop(t);
1152                 put_task_struct(t);
1153         }
1154 out_mput:
1155         module_put(desc->owner);
1156         return ret;
1157 }
1158
1159 /**
1160  *      setup_irq - setup an interrupt
1161  *      @irq: Interrupt line to setup
1162  *      @act: irqaction for the interrupt
1163  *
1164  * Used to statically setup interrupts in the early boot process.
1165  */
1166 int setup_irq(unsigned int irq, struct irqaction *act)
1167 {
1168         int retval;
1169         struct irq_desc *desc = irq_to_desc(irq);
1170
1171         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1172                 return -EINVAL;
1173         chip_bus_lock(desc);
1174         retval = __setup_irq(irq, desc, act);
1175         chip_bus_sync_unlock(desc);
1176
1177         return retval;
1178 }
1179 EXPORT_SYMBOL_GPL(setup_irq);
1180
1181 /*
1182  * Internal function to unregister an irqaction - used to free
1183  * regular and special interrupts that are part of the architecture.
1184  */
1185 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1186 {
1187         struct irq_desc *desc = irq_to_desc(irq);
1188         struct irqaction *action, **action_ptr;
1189         unsigned long flags;
1190
1191         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1192
1193         if (!desc)
1194                 return NULL;
1195
1196         raw_spin_lock_irqsave(&desc->lock, flags);
1197
1198         /*
1199          * There can be multiple actions per IRQ descriptor, find the right
1200          * one based on the dev_id:
1201          */
1202         action_ptr = &desc->action;
1203         for (;;) {
1204                 action = *action_ptr;
1205
1206                 if (!action) {
1207                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1208                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1209
1210                         return NULL;
1211                 }
1212
1213                 if (action->dev_id == dev_id)
1214                         break;
1215                 action_ptr = &action->next;
1216         }
1217
1218         /* Found it - now remove it from the list of entries: */
1219         *action_ptr = action->next;
1220
1221         /* If this was the last handler, shut down the IRQ line: */
1222         if (!desc->action)
1223                 irq_shutdown(desc);
1224
1225 #ifdef CONFIG_SMP
1226         /* make sure affinity_hint is cleaned up */
1227         if (WARN_ON_ONCE(desc->affinity_hint))
1228                 desc->affinity_hint = NULL;
1229 #endif
1230
1231         raw_spin_unlock_irqrestore(&desc->lock, flags);
1232
1233         unregister_handler_proc(irq, action);
1234
1235         /* Make sure it's not being used on another CPU: */
1236         synchronize_irq(irq);
1237
1238 #ifdef CONFIG_DEBUG_SHIRQ
1239         /*
1240          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1241          * event to happen even now it's being freed, so let's make sure that
1242          * is so by doing an extra call to the handler ....
1243          *
1244          * ( We do this after actually deregistering it, to make sure that a
1245          *   'real' IRQ doesn't run in * parallel with our fake. )
1246          */
1247         if (action->flags & IRQF_SHARED) {
1248                 local_irq_save(flags);
1249                 action->handler(irq, dev_id);
1250                 local_irq_restore(flags);
1251         }
1252 #endif
1253
1254         if (action->thread) {
1255                 kthread_stop(action->thread);
1256                 put_task_struct(action->thread);
1257         }
1258
1259         module_put(desc->owner);
1260         return action;
1261 }
1262
1263 /**
1264  *      remove_irq - free an interrupt
1265  *      @irq: Interrupt line to free
1266  *      @act: irqaction for the interrupt
1267  *
1268  * Used to remove interrupts statically setup by the early boot process.
1269  */
1270 void remove_irq(unsigned int irq, struct irqaction *act)
1271 {
1272         struct irq_desc *desc = irq_to_desc(irq);
1273
1274         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1275             __free_irq(irq, act->dev_id);
1276 }
1277 EXPORT_SYMBOL_GPL(remove_irq);
1278
1279 /**
1280  *      free_irq - free an interrupt allocated with request_irq
1281  *      @irq: Interrupt line to free
1282  *      @dev_id: Device identity to free
1283  *
1284  *      Remove an interrupt handler. The handler is removed and if the
1285  *      interrupt line is no longer in use by any driver it is disabled.
1286  *      On a shared IRQ the caller must ensure the interrupt is disabled
1287  *      on the card it drives before calling this function. The function
1288  *      does not return until any executing interrupts for this IRQ
1289  *      have completed.
1290  *
1291  *      This function must not be called from interrupt context.
1292  */
1293 void free_irq(unsigned int irq, void *dev_id)
1294 {
1295         struct irq_desc *desc = irq_to_desc(irq);
1296
1297         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1298                 return;
1299
1300 #ifdef CONFIG_SMP
1301         if (WARN_ON(desc->affinity_notify))
1302                 desc->affinity_notify = NULL;
1303 #endif
1304
1305         chip_bus_lock(desc);
1306         kfree(__free_irq(irq, dev_id));
1307         chip_bus_sync_unlock(desc);
1308 }
1309 EXPORT_SYMBOL(free_irq);
1310
1311 /**
1312  *      request_threaded_irq - allocate an interrupt line
1313  *      @irq: Interrupt line to allocate
1314  *      @handler: Function to be called when the IRQ occurs.
1315  *                Primary handler for threaded interrupts
1316  *                If NULL and thread_fn != NULL the default
1317  *                primary handler is installed
1318  *      @thread_fn: Function called from the irq handler thread
1319  *                  If NULL, no irq thread is created
1320  *      @irqflags: Interrupt type flags
1321  *      @devname: An ascii name for the claiming device
1322  *      @dev_id: A cookie passed back to the handler function
1323  *
1324  *      This call allocates interrupt resources and enables the
1325  *      interrupt line and IRQ handling. From the point this
1326  *      call is made your handler function may be invoked. Since
1327  *      your handler function must clear any interrupt the board
1328  *      raises, you must take care both to initialise your hardware
1329  *      and to set up the interrupt handler in the right order.
1330  *
1331  *      If you want to set up a threaded irq handler for your device
1332  *      then you need to supply @handler and @thread_fn. @handler is
1333  *      still called in hard interrupt context and has to check
1334  *      whether the interrupt originates from the device. If yes it
1335  *      needs to disable the interrupt on the device and return
1336  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1337  *      @thread_fn. This split handler design is necessary to support
1338  *      shared interrupts.
1339  *
1340  *      Dev_id must be globally unique. Normally the address of the
1341  *      device data structure is used as the cookie. Since the handler
1342  *      receives this value it makes sense to use it.
1343  *
1344  *      If your interrupt is shared you must pass a non NULL dev_id
1345  *      as this is required when freeing the interrupt.
1346  *
1347  *      Flags:
1348  *
1349  *      IRQF_SHARED             Interrupt is shared
1350  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1351  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1352  *
1353  */
1354 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1355                          irq_handler_t thread_fn, unsigned long irqflags,
1356                          const char *devname, void *dev_id)
1357 {
1358         struct irqaction *action;
1359         struct irq_desc *desc;
1360         int retval;
1361
1362         /*
1363          * Sanity-check: shared interrupts must pass in a real dev-ID,
1364          * otherwise we'll have trouble later trying to figure out
1365          * which interrupt is which (messes up the interrupt freeing
1366          * logic etc).
1367          */
1368         if ((irqflags & IRQF_SHARED) && !dev_id)
1369                 return -EINVAL;
1370
1371         desc = irq_to_desc(irq);
1372         if (!desc)
1373                 return -EINVAL;
1374
1375         if (!irq_settings_can_request(desc) ||
1376             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1377                 return -EINVAL;
1378
1379         if (!handler) {
1380                 if (!thread_fn)
1381                         return -EINVAL;
1382                 handler = irq_default_primary_handler;
1383         }
1384
1385         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1386         if (!action)
1387                 return -ENOMEM;
1388
1389         action->handler = handler;
1390         action->thread_fn = thread_fn;
1391         action->flags = irqflags;
1392         action->name = devname;
1393         action->dev_id = dev_id;
1394
1395         chip_bus_lock(desc);
1396         retval = __setup_irq(irq, desc, action);
1397         chip_bus_sync_unlock(desc);
1398
1399         if (retval)
1400                 kfree(action);
1401
1402 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1403         if (!retval && (irqflags & IRQF_SHARED)) {
1404                 /*
1405                  * It's a shared IRQ -- the driver ought to be prepared for it
1406                  * to happen immediately, so let's make sure....
1407                  * We disable the irq to make sure that a 'real' IRQ doesn't
1408                  * run in parallel with our fake.
1409                  */
1410                 unsigned long flags;
1411
1412                 disable_irq(irq);
1413                 local_irq_save(flags);
1414
1415                 handler(irq, dev_id);
1416
1417                 local_irq_restore(flags);
1418                 enable_irq(irq);
1419         }
1420 #endif
1421         return retval;
1422 }
1423 EXPORT_SYMBOL(request_threaded_irq);
1424
1425 /**
1426  *      request_any_context_irq - allocate an interrupt line
1427  *      @irq: Interrupt line to allocate
1428  *      @handler: Function to be called when the IRQ occurs.
1429  *                Threaded handler for threaded interrupts.
1430  *      @flags: Interrupt type flags
1431  *      @name: An ascii name for the claiming device
1432  *      @dev_id: A cookie passed back to the handler function
1433  *
1434  *      This call allocates interrupt resources and enables the
1435  *      interrupt line and IRQ handling. It selects either a
1436  *      hardirq or threaded handling method depending on the
1437  *      context.
1438  *
1439  *      On failure, it returns a negative value. On success,
1440  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1441  */
1442 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1443                             unsigned long flags, const char *name, void *dev_id)
1444 {
1445         struct irq_desc *desc = irq_to_desc(irq);
1446         int ret;
1447
1448         if (!desc)
1449                 return -EINVAL;
1450
1451         if (irq_settings_is_nested_thread(desc)) {
1452                 ret = request_threaded_irq(irq, NULL, handler,
1453                                            flags, name, dev_id);
1454                 return !ret ? IRQC_IS_NESTED : ret;
1455         }
1456
1457         ret = request_irq(irq, handler, flags, name, dev_id);
1458         return !ret ? IRQC_IS_HARDIRQ : ret;
1459 }
1460 EXPORT_SYMBOL_GPL(request_any_context_irq);
1461
1462 void enable_percpu_irq(unsigned int irq, unsigned int type)
1463 {
1464         unsigned int cpu = smp_processor_id();
1465         unsigned long flags;
1466         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1467
1468         if (!desc)
1469                 return;
1470
1471         type &= IRQ_TYPE_SENSE_MASK;
1472         if (type != IRQ_TYPE_NONE) {
1473                 int ret;
1474
1475                 ret = __irq_set_trigger(desc, irq, type);
1476
1477                 if (ret) {
1478                         WARN(1, "failed to set type for IRQ%d\n", irq);
1479                         goto out;
1480                 }
1481         }
1482
1483         irq_percpu_enable(desc, cpu);
1484 out:
1485         irq_put_desc_unlock(desc, flags);
1486 }
1487
1488 void disable_percpu_irq(unsigned int irq)
1489 {
1490         unsigned int cpu = smp_processor_id();
1491         unsigned long flags;
1492         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1493
1494         if (!desc)
1495                 return;
1496
1497         irq_percpu_disable(desc, cpu);
1498         irq_put_desc_unlock(desc, flags);
1499 }
1500
1501 /*
1502  * Internal function to unregister a percpu irqaction.
1503  */
1504 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1505 {
1506         struct irq_desc *desc = irq_to_desc(irq);
1507         struct irqaction *action;
1508         unsigned long flags;
1509
1510         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1511
1512         if (!desc)
1513                 return NULL;
1514
1515         raw_spin_lock_irqsave(&desc->lock, flags);
1516
1517         action = desc->action;
1518         if (!action || action->percpu_dev_id != dev_id) {
1519                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1520                 goto bad;
1521         }
1522
1523         if (!cpumask_empty(desc->percpu_enabled)) {
1524                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1525                      irq, cpumask_first(desc->percpu_enabled));
1526                 goto bad;
1527         }
1528
1529         /* Found it - now remove it from the list of entries: */
1530         desc->action = NULL;
1531
1532         raw_spin_unlock_irqrestore(&desc->lock, flags);
1533
1534         unregister_handler_proc(irq, action);
1535
1536         module_put(desc->owner);
1537         return action;
1538
1539 bad:
1540         raw_spin_unlock_irqrestore(&desc->lock, flags);
1541         return NULL;
1542 }
1543
1544 /**
1545  *      remove_percpu_irq - free a per-cpu interrupt
1546  *      @irq: Interrupt line to free
1547  *      @act: irqaction for the interrupt
1548  *
1549  * Used to remove interrupts statically setup by the early boot process.
1550  */
1551 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1552 {
1553         struct irq_desc *desc = irq_to_desc(irq);
1554
1555         if (desc && irq_settings_is_per_cpu_devid(desc))
1556             __free_percpu_irq(irq, act->percpu_dev_id);
1557 }
1558
1559 /**
1560  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1561  *      @irq: Interrupt line to free
1562  *      @dev_id: Device identity to free
1563  *
1564  *      Remove a percpu interrupt handler. The handler is removed, but
1565  *      the interrupt line is not disabled. This must be done on each
1566  *      CPU before calling this function. The function does not return
1567  *      until any executing interrupts for this IRQ have completed.
1568  *
1569  *      This function must not be called from interrupt context.
1570  */
1571 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1572 {
1573         struct irq_desc *desc = irq_to_desc(irq);
1574
1575         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1576                 return;
1577
1578         chip_bus_lock(desc);
1579         kfree(__free_percpu_irq(irq, dev_id));
1580         chip_bus_sync_unlock(desc);
1581 }
1582
1583 /**
1584  *      setup_percpu_irq - setup a per-cpu interrupt
1585  *      @irq: Interrupt line to setup
1586  *      @act: irqaction for the interrupt
1587  *
1588  * Used to statically setup per-cpu interrupts in the early boot process.
1589  */
1590 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1591 {
1592         struct irq_desc *desc = irq_to_desc(irq);
1593         int retval;
1594
1595         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1596                 return -EINVAL;
1597         chip_bus_lock(desc);
1598         retval = __setup_irq(irq, desc, act);
1599         chip_bus_sync_unlock(desc);
1600
1601         return retval;
1602 }
1603
1604 /**
1605  *      request_percpu_irq - allocate a percpu interrupt line
1606  *      @irq: Interrupt line to allocate
1607  *      @handler: Function to be called when the IRQ occurs.
1608  *      @devname: An ascii name for the claiming device
1609  *      @dev_id: A percpu cookie passed back to the handler function
1610  *
1611  *      This call allocates interrupt resources, but doesn't
1612  *      automatically enable the interrupt. It has to be done on each
1613  *      CPU using enable_percpu_irq().
1614  *
1615  *      Dev_id must be globally unique. It is a per-cpu variable, and
1616  *      the handler gets called with the interrupted CPU's instance of
1617  *      that variable.
1618  */
1619 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1620                        const char *devname, void __percpu *dev_id)
1621 {
1622         struct irqaction *action;
1623         struct irq_desc *desc;
1624         int retval;
1625
1626         if (!dev_id)
1627                 return -EINVAL;
1628
1629         desc = irq_to_desc(irq);
1630         if (!desc || !irq_settings_can_request(desc) ||
1631             !irq_settings_is_per_cpu_devid(desc))
1632                 return -EINVAL;
1633
1634         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1635         if (!action)
1636                 return -ENOMEM;
1637
1638         action->handler = handler;
1639         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1640         action->name = devname;
1641         action->percpu_dev_id = dev_id;
1642
1643         chip_bus_lock(desc);
1644         retval = __setup_irq(irq, desc, action);
1645         chip_bus_sync_unlock(desc);
1646
1647         if (retval)
1648                 kfree(action);
1649
1650         return retval;
1651 }