1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
4  * Copyright (C) 2005-2006 Thomas Gleixner
5  *
6  * This file contains driver APIs to the irq subsystem.
7  */
8 
9 #define pr_fmt(fmt) "genirq: " fmt
10 
11 #include <linux/irq.h>
12 #include <linux/kthread.h>
13 #include <linux/module.h>
14 #include <linux/random.h>
15 #include <linux/interrupt.h>
16 #include <linux/irqdomain.h>
17 #include <linux/slab.h>
18 #include <linux/sched.h>
19 #include <linux/sched/rt.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/isolation.h>
22 #include <uapi/linux/sched/types.h>
23 #include <linux/task_work.h>
24 
25 #include "internals.h"
26 
27 #if defined(CONFIG_IRQ_FORCED_THREADING) && !defined(CONFIG_PREEMPT_RT)
28 DEFINE_STATIC_KEY_FALSE(force_irqthreads_key);
29 
setup_forced_irqthreads(char * arg)30 static int __init setup_forced_irqthreads(char *arg)
31 {
32 	static_branch_enable(&force_irqthreads_key);
33 	return 0;
34 }
35 early_param("threadirqs", setup_forced_irqthreads);
36 #endif
37 
__synchronize_hardirq(struct irq_desc * desc,bool sync_chip)38 static void __synchronize_hardirq(struct irq_desc *desc, bool sync_chip)
39 {
40 	struct irq_data *irqd = irq_desc_get_irq_data(desc);
41 	bool inprogress;
42 
43 	do {
44 		unsigned long flags;
45 
46 		/*
47 		 * Wait until we're out of the critical section.  This might
48 		 * give the wrong answer due to the lack of memory barriers.
49 		 */
50 		while (irqd_irq_inprogress(&desc->irq_data))
51 			cpu_relax();
52 
53 		/* Ok, that indicated we're done: double-check carefully. */
54 		raw_spin_lock_irqsave(&desc->lock, flags);
55 		inprogress = irqd_irq_inprogress(&desc->irq_data);
56 
57 		/*
58 		 * If requested and supported, check at the chip whether it
59 		 * is in flight at the hardware level, i.e. already pending
60 		 * in a CPU and waiting for service and acknowledge.
61 		 */
62 		if (!inprogress && sync_chip) {
63 			/*
64 			 * Ignore the return code. inprogress is only updated
65 			 * when the chip supports it.
66 			 */
67 			__irq_get_irqchip_state(irqd, IRQCHIP_STATE_ACTIVE,
68 						&inprogress);
69 		}
70 		raw_spin_unlock_irqrestore(&desc->lock, flags);
71 
72 		/* Oops, that failed? */
73 	} while (inprogress);
74 }
75 
76 /**
77  *	synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
78  *	@irq: interrupt number to wait for
79  *
80  *	This function waits for any pending hard IRQ handlers for this
81  *	interrupt to complete before returning. If you use this
82  *	function while holding a resource the IRQ handler may need you
83  *	will deadlock. It does not take associated threaded handlers
84  *	into account.
85  *
86  *	Do not use this for shutdown scenarios where you must be sure
87  *	that all parts (hardirq and threaded handler) have completed.
88  *
89  *	Returns: false if a threaded handler is active.
90  *
91  *	This function may be called - with care - from IRQ context.
92  *
93  *	It does not check whether there is an interrupt in flight at the
94  *	hardware level, but not serviced yet, as this might deadlock when
95  *	called with interrupts disabled and the target CPU of the interrupt
96  *	is the current CPU.
97  */
synchronize_hardirq(unsigned int irq)98 bool synchronize_hardirq(unsigned int irq)
99 {
100 	struct irq_desc *desc = irq_to_desc(irq);
101 
102 	if (desc) {
103 		__synchronize_hardirq(desc, false);
104 		return !atomic_read(&desc->threads_active);
105 	}
106 
107 	return true;
108 }
109 EXPORT_SYMBOL(synchronize_hardirq);
110 
__synchronize_irq(struct irq_desc * desc)111 static void __synchronize_irq(struct irq_desc *desc)
112 {
113 	__synchronize_hardirq(desc, true);
114 	/*
115 	 * We made sure that no hardirq handler is running. Now verify that no
116 	 * threaded handlers are active.
117 	 */
118 	wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
119 }
120 
121 /**
122  *	synchronize_irq - wait for pending IRQ handlers (on other CPUs)
123  *	@irq: interrupt number to wait for
124  *
125  *	This function waits for any pending IRQ handlers for this interrupt
126  *	to complete before returning. If you use this function while
127  *	holding a resource the IRQ handler may need you will deadlock.
128  *
129  *	Can only be called from preemptible code as it might sleep when
130  *	an interrupt thread is associated to @irq.
131  *
132  *	It optionally makes sure (when the irq chip supports that method)
133  *	that the interrupt is not pending in any CPU and waiting for
134  *	service.
135  */
synchronize_irq(unsigned int irq)136 void synchronize_irq(unsigned int irq)
137 {
138 	struct irq_desc *desc = irq_to_desc(irq);
139 
140 	if (desc)
141 		__synchronize_irq(desc);
142 }
143 EXPORT_SYMBOL(synchronize_irq);
144 
145 #ifdef CONFIG_SMP
146 cpumask_var_t irq_default_affinity;
147 
__irq_can_set_affinity(struct irq_desc * desc)148 static bool __irq_can_set_affinity(struct irq_desc *desc)
149 {
150 	if (!desc || !irqd_can_balance(&desc->irq_data) ||
151 	    !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
152 		return false;
153 	return true;
154 }
155 
156 /**
157  *	irq_can_set_affinity - Check if the affinity of a given irq can be set
158  *	@irq:		Interrupt to check
159  *
160  */
irq_can_set_affinity(unsigned int irq)161 int irq_can_set_affinity(unsigned int irq)
162 {
163 	return __irq_can_set_affinity(irq_to_desc(irq));
164 }
165 
166 /**
167  * irq_can_set_affinity_usr - Check if affinity of a irq can be set from user space
168  * @irq:	Interrupt to check
169  *
170  * Like irq_can_set_affinity() above, but additionally checks for the
171  * AFFINITY_MANAGED flag.
172  */
irq_can_set_affinity_usr(unsigned int irq)173 bool irq_can_set_affinity_usr(unsigned int irq)
174 {
175 	struct irq_desc *desc = irq_to_desc(irq);
176 
177 	return __irq_can_set_affinity(desc) &&
178 		!irqd_affinity_is_managed(&desc->irq_data);
179 }
180 
181 /**
182  *	irq_set_thread_affinity - Notify irq threads to adjust affinity
183  *	@desc:		irq descriptor which has affinity changed
184  *
185  *	We just set IRQTF_AFFINITY and delegate the affinity setting
186  *	to the interrupt thread itself. We can not call
187  *	set_cpus_allowed_ptr() here as we hold desc->lock and this
188  *	code can be called from hard interrupt context.
189  */
irq_set_thread_affinity(struct irq_desc * desc)190 void irq_set_thread_affinity(struct irq_desc *desc)
191 {
192 	struct irqaction *action;
193 
194 	for_each_action_of_desc(desc, action) {
195 		if (action->thread)
196 			set_bit(IRQTF_AFFINITY, &action->thread_flags);
197 		if (action->secondary && action->secondary->thread)
198 			set_bit(IRQTF_AFFINITY, &action->secondary->thread_flags);
199 	}
200 }
201 
202 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
irq_validate_effective_affinity(struct irq_data * data)203 static void irq_validate_effective_affinity(struct irq_data *data)
204 {
205 	const struct cpumask *m = irq_data_get_effective_affinity_mask(data);
206 	struct irq_chip *chip = irq_data_get_irq_chip(data);
207 
208 	if (!cpumask_empty(m))
209 		return;
210 	pr_warn_once("irq_chip %s did not update eff. affinity mask of irq %u\n",
211 		     chip->name, data->irq);
212 }
213 #else
irq_validate_effective_affinity(struct irq_data * data)214 static inline void irq_validate_effective_affinity(struct irq_data *data) { }
215 #endif
216 
irq_do_set_affinity(struct irq_data * data,const struct cpumask * mask,bool force)217 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
218 			bool force)
219 {
220 	struct irq_desc *desc = irq_data_to_desc(data);
221 	struct irq_chip *chip = irq_data_get_irq_chip(data);
222 	const struct cpumask  *prog_mask;
223 	int ret;
224 
225 	static DEFINE_RAW_SPINLOCK(tmp_mask_lock);
226 	static struct cpumask tmp_mask;
227 
228 	if (!chip || !chip->irq_set_affinity)
229 		return -EINVAL;
230 
231 	raw_spin_lock(&tmp_mask_lock);
232 	/*
233 	 * If this is a managed interrupt and housekeeping is enabled on
234 	 * it check whether the requested affinity mask intersects with
235 	 * a housekeeping CPU. If so, then remove the isolated CPUs from
236 	 * the mask and just keep the housekeeping CPU(s). This prevents
237 	 * the affinity setter from routing the interrupt to an isolated
238 	 * CPU to avoid that I/O submitted from a housekeeping CPU causes
239 	 * interrupts on an isolated one.
240 	 *
241 	 * If the masks do not intersect or include online CPU(s) then
242 	 * keep the requested mask. The isolated target CPUs are only
243 	 * receiving interrupts when the I/O operation was submitted
244 	 * directly from them.
245 	 *
246 	 * If all housekeeping CPUs in the affinity mask are offline, the
247 	 * interrupt will be migrated by the CPU hotplug code once a
248 	 * housekeeping CPU which belongs to the affinity mask comes
249 	 * online.
250 	 */
251 	if (irqd_affinity_is_managed(data) &&
252 	    housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) {
253 		const struct cpumask *hk_mask;
254 
255 		hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
256 
257 		cpumask_and(&tmp_mask, mask, hk_mask);
258 		if (!cpumask_intersects(&tmp_mask, cpu_online_mask))
259 			prog_mask = mask;
260 		else
261 			prog_mask = &tmp_mask;
262 	} else {
263 		prog_mask = mask;
264 	}
265 
266 	/*
267 	 * Make sure we only provide online CPUs to the irqchip,
268 	 * unless we are being asked to force the affinity (in which
269 	 * case we do as we are told).
270 	 */
271 	cpumask_and(&tmp_mask, prog_mask, cpu_online_mask);
272 	if (!force && !cpumask_empty(&tmp_mask))
273 		ret = chip->irq_set_affinity(data, &tmp_mask, force);
274 	else if (force)
275 		ret = chip->irq_set_affinity(data, mask, force);
276 	else
277 		ret = -EINVAL;
278 
279 	raw_spin_unlock(&tmp_mask_lock);
280 
281 	switch (ret) {
282 	case IRQ_SET_MASK_OK:
283 	case IRQ_SET_MASK_OK_DONE:
284 		cpumask_copy(desc->irq_common_data.affinity, mask);
285 		fallthrough;
286 	case IRQ_SET_MASK_OK_NOCOPY:
287 		irq_validate_effective_affinity(data);
288 		irq_set_thread_affinity(desc);
289 		ret = 0;
290 	}
291 
292 	return ret;
293 }
294 
295 #ifdef CONFIG_GENERIC_PENDING_IRQ
irq_set_affinity_pending(struct irq_data * data,const struct cpumask * dest)296 static inline int irq_set_affinity_pending(struct irq_data *data,
297 					   const struct cpumask *dest)
298 {
299 	struct irq_desc *desc = irq_data_to_desc(data);
300 
301 	irqd_set_move_pending(data);
302 	irq_copy_pending(desc, dest);
303 	return 0;
304 }
305 #else
irq_set_affinity_pending(struct irq_data * data,const struct cpumask * dest)306 static inline int irq_set_affinity_pending(struct irq_data *data,
307 					   const struct cpumask *dest)
308 {
309 	return -EBUSY;
310 }
311 #endif
312 
irq_try_set_affinity(struct irq_data * data,const struct cpumask * dest,bool force)313 static int irq_try_set_affinity(struct irq_data *data,
314 				const struct cpumask *dest, bool force)
315 {
316 	int ret = irq_do_set_affinity(data, dest, force);
317 
318 	/*
319 	 * In case that the underlying vector management is busy and the
320 	 * architecture supports the generic pending mechanism then utilize
321 	 * this to avoid returning an error to user space.
322 	 */
323 	if (ret == -EBUSY && !force)
324 		ret = irq_set_affinity_pending(data, dest);
325 	return ret;
326 }
327 
irq_set_affinity_deactivated(struct irq_data * data,const struct cpumask * mask)328 static bool irq_set_affinity_deactivated(struct irq_data *data,
329 					 const struct cpumask *mask)
330 {
331 	struct irq_desc *desc = irq_data_to_desc(data);
332 
333 	/*
334 	 * Handle irq chips which can handle affinity only in activated
335 	 * state correctly
336 	 *
337 	 * If the interrupt is not yet activated, just store the affinity
338 	 * mask and do not call the chip driver at all. On activation the
339 	 * driver has to make sure anyway that the interrupt is in a
340 	 * usable state so startup works.
341 	 */
342 	if (!IS_ENABLED(CONFIG_IRQ_DOMAIN_HIERARCHY) ||
343 	    irqd_is_activated(data) || !irqd_affinity_on_activate(data))
344 		return false;
345 
346 	cpumask_copy(desc->irq_common_data.affinity, mask);
347 	irq_data_update_effective_affinity(data, mask);
348 	irqd_set(data, IRQD_AFFINITY_SET);
349 	return true;
350 }
351 
irq_set_affinity_locked(struct irq_data * data,const struct cpumask * mask,bool force)352 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
353 			    bool force)
354 {
355 	struct irq_chip *chip = irq_data_get_irq_chip(data);
356 	struct irq_desc *desc = irq_data_to_desc(data);
357 	int ret = 0;
358 
359 	if (!chip || !chip->irq_set_affinity)
360 		return -EINVAL;
361 
362 	if (irq_set_affinity_deactivated(data, mask))
363 		return 0;
364 
365 	if (irq_can_move_pcntxt(data) && !irqd_is_setaffinity_pending(data)) {
366 		ret = irq_try_set_affinity(data, mask, force);
367 	} else {
368 		irqd_set_move_pending(data);
369 		irq_copy_pending(desc, mask);
370 	}
371 
372 	if (desc->affinity_notify) {
373 		kref_get(&desc->affinity_notify->kref);
374 		if (!schedule_work(&desc->affinity_notify->work)) {
375 			/* Work was already scheduled, drop our extra ref */
376 			kref_put(&desc->affinity_notify->kref,
377 				 desc->affinity_notify->release);
378 		}
379 	}
380 	irqd_set(data, IRQD_AFFINITY_SET);
381 
382 	return ret;
383 }
384 
385 /**
386  * irq_update_affinity_desc - Update affinity management for an interrupt
387  * @irq:	The interrupt number to update
388  * @affinity:	Pointer to the affinity descriptor
389  *
390  * This interface can be used to configure the affinity management of
391  * interrupts which have been allocated already.
392  *
393  * There are certain limitations on when it may be used - attempts to use it
394  * for when the kernel is configured for generic IRQ reservation mode (in
395  * config GENERIC_IRQ_RESERVATION_MODE) will fail, as it may conflict with
396  * managed/non-managed interrupt accounting. In addition, attempts to use it on
397  * an interrupt which is already started or which has already been configured
398  * as managed will also fail, as these mean invalid init state or double init.
399  */
irq_update_affinity_desc(unsigned int irq,struct irq_affinity_desc * affinity)400 int irq_update_affinity_desc(unsigned int irq,
401 			     struct irq_affinity_desc *affinity)
402 {
403 	struct irq_desc *desc;
404 	unsigned long flags;
405 	bool activated;
406 	int ret = 0;
407 
408 	/*
409 	 * Supporting this with the reservation scheme used by x86 needs
410 	 * some more thought. Fail it for now.
411 	 */
412 	if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
413 		return -EOPNOTSUPP;
414 
415 	desc = irq_get_desc_buslock(irq, &flags, 0);
416 	if (!desc)
417 		return -EINVAL;
418 
419 	/* Requires the interrupt to be shut down */
420 	if (irqd_is_started(&desc->irq_data)) {
421 		ret = -EBUSY;
422 		goto out_unlock;
423 	}
424 
425 	/* Interrupts which are already managed cannot be modified */
426 	if (irqd_affinity_is_managed(&desc->irq_data)) {
427 		ret = -EBUSY;
428 		goto out_unlock;
429 	}
430 
431 	/*
432 	 * Deactivate the interrupt. That's required to undo
433 	 * anything an earlier activation has established.
434 	 */
435 	activated = irqd_is_activated(&desc->irq_data);
436 	if (activated)
437 		irq_domain_deactivate_irq(&desc->irq_data);
438 
439 	if (affinity->is_managed) {
440 		irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED);
441 		irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN);
442 	}
443 
444 	cpumask_copy(desc->irq_common_data.affinity, &affinity->mask);
445 
446 	/* Restore the activation state */
447 	if (activated)
448 		irq_domain_activate_irq(&desc->irq_data, false);
449 
450 out_unlock:
451 	irq_put_desc_busunlock(desc, flags);
452 	return ret;
453 }
454 
__irq_set_affinity(unsigned int irq,const struct cpumask * mask,bool force)455 static int __irq_set_affinity(unsigned int irq, const struct cpumask *mask,
456 			      bool force)
457 {
458 	struct irq_desc *desc = irq_to_desc(irq);
459 	unsigned long flags;
460 	int ret;
461 
462 	if (!desc)
463 		return -EINVAL;
464 
465 	raw_spin_lock_irqsave(&desc->lock, flags);
466 	ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
467 	raw_spin_unlock_irqrestore(&desc->lock, flags);
468 	return ret;
469 }
470 
471 /**
472  * irq_set_affinity - Set the irq affinity of a given irq
473  * @irq:	Interrupt to set affinity
474  * @cpumask:	cpumask
475  *
476  * Fails if cpumask does not contain an online CPU
477  */
irq_set_affinity(unsigned int irq,const struct cpumask * cpumask)478 int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
479 {
480 	return __irq_set_affinity(irq, cpumask, false);
481 }
482 EXPORT_SYMBOL_GPL(irq_set_affinity);
483 
484 /**
485  * irq_force_affinity - Force the irq affinity of a given irq
486  * @irq:	Interrupt to set affinity
487  * @cpumask:	cpumask
488  *
489  * Same as irq_set_affinity, but without checking the mask against
490  * online cpus.
491  *
492  * Solely for low level cpu hotplug code, where we need to make per
493  * cpu interrupts affine before the cpu becomes online.
494  */
irq_force_affinity(unsigned int irq,const struct cpumask * cpumask)495 int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
496 {
497 	return __irq_set_affinity(irq, cpumask, true);
498 }
499 EXPORT_SYMBOL_GPL(irq_force_affinity);
500 
__irq_apply_affinity_hint(unsigned int irq,const struct cpumask * m,bool setaffinity)501 int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m,
502 			      bool setaffinity)
503 {
504 	unsigned long flags;
505 	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
506 
507 	if (!desc)
508 		return -EINVAL;
509 	desc->affinity_hint = m;
510 	irq_put_desc_unlock(desc, flags);
511 	if (m && setaffinity)
512 		__irq_set_affinity(irq, m, false);
513 	return 0;
514 }
515 EXPORT_SYMBOL_GPL(__irq_apply_affinity_hint);
516 
irq_affinity_notify(struct work_struct * work)517 static void irq_affinity_notify(struct work_struct *work)
518 {
519 	struct irq_affinity_notify *notify =
520 		container_of(work, struct irq_affinity_notify, work);
521 	struct irq_desc *desc = irq_to_desc(notify->irq);
522 	cpumask_var_t cpumask;
523 	unsigned long flags;
524 
525 	if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
526 		goto out;
527 
528 	raw_spin_lock_irqsave(&desc->lock, flags);
529 	if (irq_move_pending(&desc->irq_data))
530 		irq_get_pending(cpumask, desc);
531 	else
532 		cpumask_copy(cpumask, desc->irq_common_data.affinity);
533 	raw_spin_unlock_irqrestore(&desc->lock, flags);
534 
535 	notify->notify(notify, cpumask);
536 
537 	free_cpumask_var(cpumask);
538 out:
539 	kref_put(&notify->kref, notify->release);
540 }
541 
542 /**
543  *	irq_set_affinity_notifier - control notification of IRQ affinity changes
544  *	@irq:		Interrupt for which to enable/disable notification
545  *	@notify:	Context for notification, or %NULL to disable
546  *			notification.  Function pointers must be initialised;
547  *			the other fields will be initialised by this function.
548  *
549  *	Must be called in process context.  Notification may only be enabled
550  *	after the IRQ is allocated and must be disabled before the IRQ is
551  *	freed using free_irq().
552  */
553 int
irq_set_affinity_notifier(unsigned int irq,struct irq_affinity_notify * notify)554 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
555 {
556 	struct irq_desc *desc = irq_to_desc(irq);
557 	struct irq_affinity_notify *old_notify;
558 	unsigned long flags;
559 
560 	/* The release function is promised process context */
561 	might_sleep();
562 
563 	if (!desc || desc->istate & IRQS_NMI)
564 		return -EINVAL;
565 
566 	/* Complete initialisation of *notify */
567 	if (notify) {
568 		notify->irq = irq;
569 		kref_init(&notify->kref);
570 		INIT_WORK(&notify->work, irq_affinity_notify);
571 	}
572 
573 	raw_spin_lock_irqsave(&desc->lock, flags);
574 	old_notify = desc->affinity_notify;
575 	desc->affinity_notify = notify;
576 	raw_spin_unlock_irqrestore(&desc->lock, flags);
577 
578 	if (old_notify) {
579 		if (cancel_work_sync(&old_notify->work)) {
580 			/* Pending work had a ref, put that one too */
581 			kref_put(&old_notify->kref, old_notify->release);
582 		}
583 		kref_put(&old_notify->kref, old_notify->release);
584 	}
585 
586 	return 0;
587 }
588 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
589 
590 #ifndef CONFIG_AUTO_IRQ_AFFINITY
591 /*
592  * Generic version of the affinity autoselector.
593  */
irq_setup_affinity(struct irq_desc * desc)594 int irq_setup_affinity(struct irq_desc *desc)
595 {
596 	struct cpumask *set = irq_default_affinity;
597 	int ret, node = irq_desc_get_node(desc);
598 	static DEFINE_RAW_SPINLOCK(mask_lock);
599 	static struct cpumask mask;
600 
601 	/* Excludes PER_CPU and NO_BALANCE interrupts */
602 	if (!__irq_can_set_affinity(desc))
603 		return 0;
604 
605 	raw_spin_lock(&mask_lock);
606 	/*
607 	 * Preserve the managed affinity setting and a userspace affinity
608 	 * setup, but make sure that one of the targets is online.
609 	 */
610 	if (irqd_affinity_is_managed(&desc->irq_data) ||
611 	    irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
612 		if (cpumask_intersects(desc->irq_common_data.affinity,
613 				       cpu_online_mask))
614 			set = desc->irq_common_data.affinity;
615 		else
616 			irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
617 	}
618 
619 	cpumask_and(&mask, cpu_online_mask, set);
620 	if (cpumask_empty(&mask))
621 		cpumask_copy(&mask, cpu_online_mask);
622 
623 	if (node != NUMA_NO_NODE) {
624 		const struct cpumask *nodemask = cpumask_of_node(node);
625 
626 		/* make sure at least one of the cpus in nodemask is online */
627 		if (cpumask_intersects(&mask, nodemask))
628 			cpumask_and(&mask, &mask, nodemask);
629 	}
630 	ret = irq_do_set_affinity(&desc->irq_data, &mask, false);
631 	raw_spin_unlock(&mask_lock);
632 	return ret;
633 }
634 #else
635 /* Wrapper for ALPHA specific affinity selector magic */
irq_setup_affinity(struct irq_desc * desc)636 int irq_setup_affinity(struct irq_desc *desc)
637 {
638 	return irq_select_affinity(irq_desc_get_irq(desc));
639 }
640 #endif /* CONFIG_AUTO_IRQ_AFFINITY */
641 #endif /* CONFIG_SMP */
642 
643 
644 /**
645  *	irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
646  *	@irq: interrupt number to set affinity
647  *	@vcpu_info: vCPU specific data or pointer to a percpu array of vCPU
648  *	            specific data for percpu_devid interrupts
649  *
650  *	This function uses the vCPU specific data to set the vCPU
651  *	affinity for an irq. The vCPU specific data is passed from
652  *	outside, such as KVM. One example code path is as below:
653  *	KVM -> IOMMU -> irq_set_vcpu_affinity().
654  */
irq_set_vcpu_affinity(unsigned int irq,void * vcpu_info)655 int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
656 {
657 	unsigned long flags;
658 	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
659 	struct irq_data *data;
660 	struct irq_chip *chip;
661 	int ret = -ENOSYS;
662 
663 	if (!desc)
664 		return -EINVAL;
665 
666 	data = irq_desc_get_irq_data(desc);
667 	do {
668 		chip = irq_data_get_irq_chip(data);
669 		if (chip && chip->irq_set_vcpu_affinity)
670 			break;
671 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
672 		data = data->parent_data;
673 #else
674 		data = NULL;
675 #endif
676 	} while (data);
677 
678 	if (data)
679 		ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
680 	irq_put_desc_unlock(desc, flags);
681 
682 	return ret;
683 }
684 EXPORT_SYMBOL_GPL(irq_set_vcpu_affinity);
685 
__disable_irq(struct irq_desc * desc)686 void __disable_irq(struct irq_desc *desc)
687 {
688 	if (!desc->depth++)
689 		irq_disable(desc);
690 }
691 
__disable_irq_nosync(unsigned int irq)692 static int __disable_irq_nosync(unsigned int irq)
693 {
694 	unsigned long flags;
695 	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
696 
697 	if (!desc)
698 		return -EINVAL;
699 	__disable_irq(desc);
700 	irq_put_desc_busunlock(desc, flags);
701 	return 0;
702 }
703 
704 /**
705  *	disable_irq_nosync - disable an irq without waiting
706  *	@irq: Interrupt to disable
707  *
708  *	Disable the selected interrupt line.  Disables and Enables are
709  *	nested.
710  *	Unlike disable_irq(), this function does not ensure existing
711  *	instances of the IRQ handler have completed before returning.
712  *
713  *	This function may be called from IRQ context.
714  */
disable_irq_nosync(unsigned int irq)715 void disable_irq_nosync(unsigned int irq)
716 {
717 	__disable_irq_nosync(irq);
718 }
719 EXPORT_SYMBOL(disable_irq_nosync);
720 
721 /**
722  *	disable_irq - disable an irq and wait for completion
723  *	@irq: Interrupt to disable
724  *
725  *	Disable the selected interrupt line.  Enables and Disables are
726  *	nested.
727  *	This function waits for any pending IRQ handlers for this interrupt
728  *	to complete before returning. If you use this function while
729  *	holding a resource the IRQ handler may need you will deadlock.
730  *
731  *	Can only be called from preemptible code as it might sleep when
732  *	an interrupt thread is associated to @irq.
733  *
734  */
disable_irq(unsigned int irq)735 void disable_irq(unsigned int irq)
736 {
737 	might_sleep();
738 	if (!__disable_irq_nosync(irq))
739 		synchronize_irq(irq);
740 }
741 EXPORT_SYMBOL(disable_irq);
742 
743 /**
744  *	disable_hardirq - disables an irq and waits for hardirq completion
745  *	@irq: Interrupt to disable
746  *
747  *	Disable the selected interrupt line.  Enables and Disables are
748  *	nested.
749  *	This function waits for any pending hard IRQ handlers for this
750  *	interrupt to complete before returning. If you use this function while
751  *	holding a resource the hard IRQ handler may need you will deadlock.
752  *
753  *	When used to optimistically disable an interrupt from atomic context
754  *	the return value must be checked.
755  *
756  *	Returns: false if a threaded handler is active.
757  *
758  *	This function may be called - with care - from IRQ context.
759  */
disable_hardirq(unsigned int irq)760 bool disable_hardirq(unsigned int irq)
761 {
762 	if (!__disable_irq_nosync(irq))
763 		return synchronize_hardirq(irq);
764 
765 	return false;
766 }
767 EXPORT_SYMBOL_GPL(disable_hardirq);
768 
769 /**
770  *	disable_nmi_nosync - disable an nmi without waiting
771  *	@irq: Interrupt to disable
772  *
773  *	Disable the selected interrupt line. Disables and enables are
774  *	nested.
775  *	The interrupt to disable must have been requested through request_nmi.
776  *	Unlike disable_nmi(), this function does not ensure existing
777  *	instances of the IRQ handler have completed before returning.
778  */
disable_nmi_nosync(unsigned int irq)779 void disable_nmi_nosync(unsigned int irq)
780 {
781 	disable_irq_nosync(irq);
782 }
783 
__enable_irq(struct irq_desc * desc)784 void __enable_irq(struct irq_desc *desc)
785 {
786 	switch (desc->depth) {
787 	case 0:
788  err_out:
789 		WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n",
790 		     irq_desc_get_irq(desc));
791 		break;
792 	case 1: {
793 		if (desc->istate & IRQS_SUSPENDED)
794 			goto err_out;
795 		/* Prevent probing on this irq: */
796 		irq_settings_set_noprobe(desc);
797 		/*
798 		 * Call irq_startup() not irq_enable() here because the
799 		 * interrupt might be marked NOAUTOEN. So irq_startup()
800 		 * needs to be invoked when it gets enabled the first
801 		 * time. If it was already started up, then irq_startup()
802 		 * will invoke irq_enable() under the hood.
803 		 */
804 		irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
805 		break;
806 	}
807 	default:
808 		desc->depth--;
809 	}
810 }
811 
812 /**
813  *	enable_irq - enable handling of an irq
814  *	@irq: Interrupt to enable
815  *
816  *	Undoes the effect of one call to disable_irq().  If this
817  *	matches the last disable, processing of interrupts on this
818  *	IRQ line is re-enabled.
819  *
820  *	This function may be called from IRQ context only when
821  *	desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
822  */
enable_irq(unsigned int irq)823 void enable_irq(unsigned int irq)
824 {
825 	unsigned long flags;
826 	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
827 
828 	if (!desc)
829 		return;
830 	if (WARN(!desc->irq_data.chip,
831 		 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
832 		goto out;
833 
834 	__enable_irq(desc);
835 out:
836 	irq_put_desc_busunlock(desc, flags);
837 }
838 EXPORT_SYMBOL(enable_irq);
839 
840 /**
841  *	enable_nmi - enable handling of an nmi
842  *	@irq: Interrupt to enable
843  *
844  *	The interrupt to enable must have been requested through request_nmi.
845  *	Undoes the effect of one call to disable_nmi(). If this
846  *	matches the last disable, processing of interrupts on this
847  *	IRQ line is re-enabled.
848  */
enable_nmi(unsigned int irq)849 void enable_nmi(unsigned int irq)
850 {
851 	enable_irq(irq);
852 }
853 
set_irq_wake_real(unsigned int irq,unsigned int on)854 static int set_irq_wake_real(unsigned int irq, unsigned int on)
855 {
856 	struct irq_desc *desc = irq_to_desc(irq);
857 	int ret = -ENXIO;
858 
859 	if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
860 		return 0;
861 
862 	if (desc->irq_data.chip->irq_set_wake)
863 		ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
864 
865 	return ret;
866 }
867 
868 /**
869  *	irq_set_irq_wake - control irq power management wakeup
870  *	@irq:	interrupt to control
871  *	@on:	enable/disable power management wakeup
872  *
873  *	Enable/disable power management wakeup mode, which is
874  *	disabled by default.  Enables and disables must match,
875  *	just as they match for non-wakeup mode support.
876  *
877  *	Wakeup mode lets this IRQ wake the system from sleep
878  *	states like "suspend to RAM".
879  *
880  *	Note: irq enable/disable state is completely orthogonal
881  *	to the enable/disable state of irq wake. An irq can be
882  *	disabled with disable_irq() and still wake the system as
883  *	long as the irq has wake enabled. If this does not hold,
884  *	then the underlying irq chip and the related driver need
885  *	to be investigated.
886  */
irq_set_irq_wake(unsigned int irq,unsigned int on)887 int irq_set_irq_wake(unsigned int irq, unsigned int on)
888 {
889 	unsigned long flags;
890 	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
891 	int ret = 0;
892 
893 	if (!desc)
894 		return -EINVAL;
895 
896 	/* Don't use NMIs as wake up interrupts please */
897 	if (desc->istate & IRQS_NMI) {
898 		ret = -EINVAL;
899 		goto out_unlock;
900 	}
901 
902 	/* wakeup-capable irqs can be shared between drivers that
903 	 * don't need to have the same sleep mode behaviors.
904 	 */
905 	if (on) {
906 		if (desc->wake_depth++ == 0) {
907 			ret = set_irq_wake_real(irq, on);
908 			if (ret)
909 				desc->wake_depth = 0;
910 			else
911 				irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
912 		}
913 	} else {
914 		if (desc->wake_depth == 0) {
915 			WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
916 		} else if (--desc->wake_depth == 0) {
917 			ret = set_irq_wake_real(irq, on);
918 			if (ret)
919 				desc->wake_depth = 1;
920 			else
921 				irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
922 		}
923 	}
924 
925 out_unlock:
926 	irq_put_desc_busunlock(desc, flags);
927 	return ret;
928 }
929 EXPORT_SYMBOL(irq_set_irq_wake);
930 
931 /*
932  * Internal function that tells the architecture code whether a
933  * particular irq has been exclusively allocated or is available
934  * for driver use.
935  */
can_request_irq(unsigned int irq,unsigned long irqflags)936 int can_request_irq(unsigned int irq, unsigned long irqflags)
937 {
938 	unsigned long flags;
939 	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
940 	int canrequest = 0;
941 
942 	if (!desc)
943 		return 0;
944 
945 	if (irq_settings_can_request(desc)) {
946 		if (!desc->action ||
947 		    irqflags & desc->action->flags & IRQF_SHARED)
948 			canrequest = 1;
949 	}
950 	irq_put_desc_unlock(desc, flags);
951 	return canrequest;
952 }
953 
__irq_set_trigger(struct irq_desc * desc,unsigned long flags)954 int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
955 {
956 	struct irq_chip *chip = desc->irq_data.chip;
957 	int ret, unmask = 0;
958 
959 	if (!chip || !chip->irq_set_type) {
960 		/*
961 		 * IRQF_TRIGGER_* but the PIC does not support multiple
962 		 * flow-types?
963 		 */
964 		pr_debug("No set_type function for IRQ %d (%s)\n",
965 			 irq_desc_get_irq(desc),
966 			 chip ? (chip->name ? : "unknown") : "unknown");
967 		return 0;
968 	}
969 
970 	if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
971 		if (!irqd_irq_masked(&desc->irq_data))
972 			mask_irq(desc);
973 		if (!irqd_irq_disabled(&desc->irq_data))
974 			unmask = 1;
975 	}
976 
977 	/* Mask all flags except trigger mode */
978 	flags &= IRQ_TYPE_SENSE_MASK;
979 	ret = chip->irq_set_type(&desc->irq_data, flags);
980 
981 	switch (ret) {
982 	case IRQ_SET_MASK_OK:
983 	case IRQ_SET_MASK_OK_DONE:
984 		irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
985 		irqd_set(&desc->irq_data, flags);
986 		fallthrough;
987 
988 	case IRQ_SET_MASK_OK_NOCOPY:
989 		flags = irqd_get_trigger_type(&desc->irq_data);
990 		irq_settings_set_trigger_mask(desc, flags);
991 		irqd_clear(&desc->irq_data, IRQD_LEVEL);
992 		irq_settings_clr_level(desc);
993 		if (flags & IRQ_TYPE_LEVEL_MASK) {
994 			irq_settings_set_level(desc);
995 			irqd_set(&desc->irq_data, IRQD_LEVEL);
996 		}
997 
998 		ret = 0;
999 		break;
1000 	default:
1001 		pr_err("Setting trigger mode %lu for irq %u failed (%pS)\n",
1002 		       flags, irq_desc_get_irq(desc), chip->irq_set_type);
1003 	}
1004 	if (unmask)
1005 		unmask_irq(desc);
1006 	return ret;
1007 }
1008 
1009 #ifdef CONFIG_HARDIRQS_SW_RESEND
irq_set_parent(int irq,int parent_irq)1010 int irq_set_parent(int irq, int parent_irq)
1011 {
1012 	unsigned long flags;
1013 	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
1014 
1015 	if (!desc)
1016 		return -EINVAL;
1017 
1018 	desc->parent_irq = parent_irq;
1019 
1020 	irq_put_desc_unlock(desc, flags);
1021 	return 0;
1022 }
1023 EXPORT_SYMBOL_GPL(irq_set_parent);
1024 #endif
1025 
1026 /*
1027  * Default primary interrupt handler for threaded interrupts. Is
1028  * assigned as primary handler when request_threaded_irq is called
1029  * with handler == NULL. Useful for oneshot interrupts.
1030  */
irq_default_primary_handler(int irq,void * dev_id)1031 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
1032 {
1033 	return IRQ_WAKE_THREAD;
1034 }
1035 
1036 /*
1037  * Primary handler for nested threaded interrupts. Should never be
1038  * called.
1039  */
irq_nested_primary_handler(int irq,void * dev_id)1040 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
1041 {
1042 	WARN(1, "Primary handler called for nested irq %d\n", irq);
1043 	return IRQ_NONE;
1044 }
1045 
irq_forced_secondary_handler(int irq,void * dev_id)1046 static irqreturn_t irq_forced_secondary_handler(int irq, void *dev_id)
1047 {
1048 	WARN(1, "Secondary action handler called for irq %d\n", irq);
1049 	return IRQ_NONE;
1050 }
1051 
irq_wait_for_interrupt(struct irqaction * action)1052 static int irq_wait_for_interrupt(struct irqaction *action)
1053 {
1054 	for (;;) {
1055 		set_current_state(TASK_INTERRUPTIBLE);
1056 
1057 		if (kthread_should_stop()) {
1058 			/* may need to run one last time */
1059 			if (test_and_clear_bit(IRQTF_RUNTHREAD,
1060 					       &action->thread_flags)) {
1061 				__set_current_state(TASK_RUNNING);
1062 				return 0;
1063 			}
1064 			__set_current_state(TASK_RUNNING);
1065 			return -1;
1066 		}
1067 
1068 		if (test_and_clear_bit(IRQTF_RUNTHREAD,
1069 				       &action->thread_flags)) {
1070 			__set_current_state(TASK_RUNNING);
1071 			return 0;
1072 		}
1073 		schedule();
1074 	}
1075 }
1076 
1077 /*
1078  * Oneshot interrupts keep the irq line masked until the threaded
1079  * handler finished. unmask if the interrupt has not been disabled and
1080  * is marked MASKED.
1081  */
irq_finalize_oneshot(struct irq_desc * desc,struct irqaction * action)1082 static void irq_finalize_oneshot(struct irq_desc *desc,
1083 				 struct irqaction *action)
1084 {
1085 	if (!(desc->istate & IRQS_ONESHOT) ||
1086 	    action->handler == irq_forced_secondary_handler)
1087 		return;
1088 again:
1089 	chip_bus_lock(desc);
1090 	raw_spin_lock_irq(&desc->lock);
1091 
1092 	/*
1093 	 * Implausible though it may be we need to protect us against
1094 	 * the following scenario:
1095 	 *
1096 	 * The thread is faster done than the hard interrupt handler
1097 	 * on the other CPU. If we unmask the irq line then the
1098 	 * interrupt can come in again and masks the line, leaves due
1099 	 * to IRQS_INPROGRESS and the irq line is masked forever.
1100 	 *
1101 	 * This also serializes the state of shared oneshot handlers
1102 	 * versus "desc->threads_oneshot |= action->thread_mask;" in
1103 	 * irq_wake_thread(). See the comment there which explains the
1104 	 * serialization.
1105 	 */
1106 	if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
1107 		raw_spin_unlock_irq(&desc->lock);
1108 		chip_bus_sync_unlock(desc);
1109 		cpu_relax();
1110 		goto again;
1111 	}
1112 
1113 	/*
1114 	 * Now check again, whether the thread should run. Otherwise
1115 	 * we would clear the threads_oneshot bit of this thread which
1116 	 * was just set.
1117 	 */
1118 	if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
1119 		goto out_unlock;
1120 
1121 	desc->threads_oneshot &= ~action->thread_mask;
1122 
1123 	if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
1124 	    irqd_irq_masked(&desc->irq_data))
1125 		unmask_threaded_irq(desc);
1126 
1127 out_unlock:
1128 	raw_spin_unlock_irq(&desc->lock);
1129 	chip_bus_sync_unlock(desc);
1130 }
1131 
1132 #ifdef CONFIG_SMP
1133 /*
1134  * Check whether we need to change the affinity of the interrupt thread.
1135  */
1136 static void
irq_thread_check_affinity(struct irq_desc * desc,struct irqaction * action)1137 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
1138 {
1139 	cpumask_var_t mask;
1140 	bool valid = true;
1141 
1142 	if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
1143 		return;
1144 
1145 	/*
1146 	 * In case we are out of memory we set IRQTF_AFFINITY again and
1147 	 * try again next time
1148 	 */
1149 	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1150 		set_bit(IRQTF_AFFINITY, &action->thread_flags);
1151 		return;
1152 	}
1153 
1154 	raw_spin_lock_irq(&desc->lock);
1155 	/*
1156 	 * This code is triggered unconditionally. Check the affinity
1157 	 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
1158 	 */
1159 	if (cpumask_available(desc->irq_common_data.affinity)) {
1160 		const struct cpumask *m;
1161 
1162 		m = irq_data_get_effective_affinity_mask(&desc->irq_data);
1163 		cpumask_copy(mask, m);
1164 	} else {
1165 		valid = false;
1166 	}
1167 	raw_spin_unlock_irq(&desc->lock);
1168 
1169 	if (valid)
1170 		set_cpus_allowed_ptr(current, mask);
1171 	free_cpumask_var(mask);
1172 }
1173 #else
1174 static inline void
irq_thread_check_affinity(struct irq_desc * desc,struct irqaction * action)1175 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
1176 #endif
1177 
1178 /*
1179  * Interrupts which are not explicitly requested as threaded
1180  * interrupts rely on the implicit bh/preempt disable of the hard irq
1181  * context. So we need to disable bh here to avoid deadlocks and other
1182  * side effects.
1183  */
1184 static irqreturn_t
irq_forced_thread_fn(struct irq_desc * desc,struct irqaction * action)1185 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
1186 {
1187 	irqreturn_t ret;
1188 
1189 	local_bh_disable();
1190 	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
1191 		local_irq_disable();
1192 	ret = action->thread_fn(action->irq, action->dev_id);
1193 	if (ret == IRQ_HANDLED)
1194 		atomic_inc(&desc->threads_handled);
1195 
1196 	irq_finalize_oneshot(desc, action);
1197 	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
1198 		local_irq_enable();
1199 	local_bh_enable();
1200 	return ret;
1201 }
1202 
1203 /*
1204  * Interrupts explicitly requested as threaded interrupts want to be
1205  * preemptible - many of them need to sleep and wait for slow busses to
1206  * complete.
1207  */
irq_thread_fn(struct irq_desc * desc,struct irqaction * action)1208 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
1209 		struct irqaction *action)
1210 {
1211 	irqreturn_t ret;
1212 
1213 	ret = action->thread_fn(action->irq, action->dev_id);
1214 	if (ret == IRQ_HANDLED)
1215 		atomic_inc(&desc->threads_handled);
1216 
1217 	irq_finalize_oneshot(desc, action);
1218 	return ret;
1219 }
1220 
wake_threads_waitq(struct irq_desc * desc)1221 void wake_threads_waitq(struct irq_desc *desc)
1222 {
1223 	if (atomic_dec_and_test(&desc->threads_active))
1224 		wake_up(&desc->wait_for_threads);
1225 }
1226 
irq_thread_dtor(struct callback_head * unused)1227 static void irq_thread_dtor(struct callback_head *unused)
1228 {
1229 	struct task_struct *tsk = current;
1230 	struct irq_desc *desc;
1231 	struct irqaction *action;
1232 
1233 	if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
1234 		return;
1235 
1236 	action = kthread_data(tsk);
1237 
1238 	pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
1239 	       tsk->comm, tsk->pid, action->irq);
1240 
1241 
1242 	desc = irq_to_desc(action->irq);
1243 	/*
1244 	 * If IRQTF_RUNTHREAD is set, we need to decrement
1245 	 * desc->threads_active and wake possible waiters.
1246 	 */
1247 	if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
1248 		wake_threads_waitq(desc);
1249 
1250 	/* Prevent a stale desc->threads_oneshot */
1251 	irq_finalize_oneshot(desc, action);
1252 }
1253 
irq_wake_secondary(struct irq_desc * desc,struct irqaction * action)1254 static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action)
1255 {
1256 	struct irqaction *secondary = action->secondary;
1257 
1258 	if (WARN_ON_ONCE(!secondary))
1259 		return;
1260 
1261 	raw_spin_lock_irq(&desc->lock);
1262 	__irq_wake_thread(desc, secondary);
1263 	raw_spin_unlock_irq(&desc->lock);
1264 }
1265 
1266 /*
1267  * Internal function to notify that a interrupt thread is ready.
1268  */
irq_thread_set_ready(struct irq_desc * desc,struct irqaction * action)1269 static void irq_thread_set_ready(struct irq_desc *desc,
1270 				 struct irqaction *action)
1271 {
1272 	set_bit(IRQTF_READY, &action->thread_flags);
1273 	wake_up(&desc->wait_for_threads);
1274 }
1275 
1276 /*
1277  * Internal function to wake up a interrupt thread and wait until it is
1278  * ready.
1279  */
wake_up_and_wait_for_irq_thread_ready(struct irq_desc * desc,struct irqaction * action)1280 static void wake_up_and_wait_for_irq_thread_ready(struct irq_desc *desc,
1281 						  struct irqaction *action)
1282 {
1283 	if (!action || !action->thread)
1284 		return;
1285 
1286 	wake_up_process(action->thread);
1287 	wait_event(desc->wait_for_threads,
1288 		   test_bit(IRQTF_READY, &action->thread_flags));
1289 }
1290 
1291 /*
1292  * Interrupt handler thread
1293  */
irq_thread(void * data)1294 static int irq_thread(void *data)
1295 {
1296 	struct callback_head on_exit_work;
1297 	struct irqaction *action = data;
1298 	struct irq_desc *desc = irq_to_desc(action->irq);
1299 	irqreturn_t (*handler_fn)(struct irq_desc *desc,
1300 			struct irqaction *action);
1301 
1302 	irq_thread_set_ready(desc, action);
1303 
1304 	sched_set_fifo(current);
1305 
1306 	if (force_irqthreads() && test_bit(IRQTF_FORCED_THREAD,
1307 					   &action->thread_flags))
1308 		handler_fn = irq_forced_thread_fn;
1309 	else
1310 		handler_fn = irq_thread_fn;
1311 
1312 	init_task_work(&on_exit_work, irq_thread_dtor);
1313 	task_work_add(current, &on_exit_work, TWA_NONE);
1314 
1315 	irq_thread_check_affinity(desc, action);
1316 
1317 	while (!irq_wait_for_interrupt(action)) {
1318 		irqreturn_t action_ret;
1319 
1320 		irq_thread_check_affinity(desc, action);
1321 
1322 		action_ret = handler_fn(desc, action);
1323 		if (action_ret == IRQ_WAKE_THREAD)
1324 			irq_wake_secondary(desc, action);
1325 
1326 		wake_threads_waitq(desc);
1327 	}
1328 
1329 	/*
1330 	 * This is the regular exit path. __free_irq() is stopping the
1331 	 * thread via kthread_stop() after calling
1332 	 * synchronize_hardirq(). So neither IRQTF_RUNTHREAD nor the
1333 	 * oneshot mask bit can be set.
1334 	 */
1335 	task_work_cancel(current, irq_thread_dtor);
1336 	return 0;
1337 }
1338 
1339 /**
1340  *	irq_wake_thread - wake the irq thread for the action identified by dev_id
1341  *	@irq:		Interrupt line
1342  *	@dev_id:	Device identity for which the thread should be woken
1343  *
1344  */
irq_wake_thread(unsigned int irq,void * dev_id)1345 void irq_wake_thread(unsigned int irq, void *dev_id)
1346 {
1347 	struct irq_desc *desc = irq_to_desc(irq);
1348 	struct irqaction *action;
1349 	unsigned long flags;
1350 
1351 	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1352 		return;
1353 
1354 	raw_spin_lock_irqsave(&desc->lock, flags);
1355 	for_each_action_of_desc(desc, action) {
1356 		if (action->dev_id == dev_id) {
1357 			if (action->thread)
1358 				__irq_wake_thread(desc, action);
1359 			break;
1360 		}
1361 	}
1362 	raw_spin_unlock_irqrestore(&desc->lock, flags);
1363 }
1364 EXPORT_SYMBOL_GPL(irq_wake_thread);
1365 
irq_setup_forced_threading(struct irqaction * new)1366 static int irq_setup_forced_threading(struct irqaction *new)
1367 {
1368 	if (!force_irqthreads())
1369 		return 0;
1370 	if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
1371 		return 0;
1372 
1373 	/*
1374 	 * No further action required for interrupts which are requested as
1375 	 * threaded interrupts already
1376 	 */
1377 	if (new->handler == irq_default_primary_handler)
1378 		return 0;
1379 
1380 	new->flags |= IRQF_ONESHOT;
1381 
1382 	/*
1383 	 * Handle the case where we have a real primary handler and a
1384 	 * thread handler. We force thread them as well by creating a
1385 	 * secondary action.
1386 	 */
1387 	if (new->handler && new->thread_fn) {
1388 		/* Allocate the secondary action */
1389 		new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1390 		if (!new->secondary)
1391 			return -ENOMEM;
1392 		new->secondary->handler = irq_forced_secondary_handler;
1393 		new->secondary->thread_fn = new->thread_fn;
1394 		new->secondary->dev_id = new->dev_id;
1395 		new->secondary->irq = new->irq;
1396 		new->secondary->name = new->name;
1397 	}
1398 	/* Deal with the primary handler */
1399 	set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
1400 	new->thread_fn = new->handler;
1401 	new->handler = irq_default_primary_handler;
1402 	return 0;
1403 }
1404 
irq_request_resources(struct irq_desc * desc)1405 static int irq_request_resources(struct irq_desc *desc)
1406 {
1407 	struct irq_data *d = &desc->irq_data;
1408 	struct irq_chip *c = d->chip;
1409 
1410 	return c->irq_request_resources ? c->irq_request_resources(d) : 0;
1411 }
1412 
irq_release_resources(struct irq_desc * desc)1413 static void irq_release_resources(struct irq_desc *desc)
1414 {
1415 	struct irq_data *d = &desc->irq_data;
1416 	struct irq_chip *c = d->chip;
1417 
1418 	if (c->irq_release_resources)
1419 		c->irq_release_resources(d);
1420 }
1421 
irq_supports_nmi(struct irq_desc * desc)1422 static bool irq_supports_nmi(struct irq_desc *desc)
1423 {
1424 	struct irq_data *d = irq_desc_get_irq_data(desc);
1425 
1426 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
1427 	/* Only IRQs directly managed by the root irqchip can be set as NMI */
1428 	if (d->parent_data)
1429 		return false;
1430 #endif
1431 	/* Don't support NMIs for chips behind a slow bus */
1432 	if (d->chip->irq_bus_lock || d->chip->irq_bus_sync_unlock)
1433 		return false;
1434 
1435 	return d->chip->flags & IRQCHIP_SUPPORTS_NMI;
1436 }
1437 
irq_nmi_setup(struct irq_desc * desc)1438 static int irq_nmi_setup(struct irq_desc *desc)
1439 {
1440 	struct irq_data *d = irq_desc_get_irq_data(desc);
1441 	struct irq_chip *c = d->chip;
1442 
1443 	return c->irq_nmi_setup ? c->irq_nmi_setup(d) : -EINVAL;
1444 }
1445 
irq_nmi_teardown(struct irq_desc * desc)1446 static void irq_nmi_teardown(struct irq_desc *desc)
1447 {
1448 	struct irq_data *d = irq_desc_get_irq_data(desc);
1449 	struct irq_chip *c = d->chip;
1450 
1451 	if (c->irq_nmi_teardown)
1452 		c->irq_nmi_teardown(d);
1453 }
1454 
1455 static int
setup_irq_thread(struct irqaction * new,unsigned int irq,bool secondary)1456 setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
1457 {
1458 	struct task_struct *t;
1459 
1460 	if (!secondary) {
1461 		t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1462 				   new->name);
1463 	} else {
1464 		t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq,
1465 				   new->name);
1466 	}
1467 
1468 	if (IS_ERR(t))
1469 		return PTR_ERR(t);
1470 
1471 	/*
1472 	 * We keep the reference to the task struct even if
1473 	 * the thread dies to avoid that the interrupt code
1474 	 * references an already freed task_struct.
1475 	 */
1476 	new->thread = get_task_struct(t);
1477 	/*
1478 	 * Tell the thread to set its affinity. This is
1479 	 * important for shared interrupt handlers as we do
1480 	 * not invoke setup_affinity() for the secondary
1481 	 * handlers as everything is already set up. Even for
1482 	 * interrupts marked with IRQF_NO_BALANCE this is
1483 	 * correct as we want the thread to move to the cpu(s)
1484 	 * on which the requesting code placed the interrupt.
1485 	 */
1486 	set_bit(IRQTF_AFFINITY, &new->thread_flags);
1487 	return 0;
1488 }
1489 
1490 /*
1491  * Internal function to register an irqaction - typically used to
1492  * allocate special interrupts that are part of the architecture.
1493  *
1494  * Locking rules:
1495  *
1496  * desc->request_mutex	Provides serialization against a concurrent free_irq()
1497  *   chip_bus_lock	Provides serialization for slow bus operations
1498  *     desc->lock	Provides serialization against hard interrupts
1499  *
1500  * chip_bus_lock and desc->lock are sufficient for all other management and
1501  * interrupt related functions. desc->request_mutex solely serializes
1502  * request/free_irq().
1503  */
1504 static int
__setup_irq(unsigned int irq,struct irq_desc * desc,struct irqaction * new)1505 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
1506 {
1507 	struct irqaction *old, **old_ptr;
1508 	unsigned long flags, thread_mask = 0;
1509 	int ret, nested, shared = 0;
1510 
1511 	if (!desc)
1512 		return -EINVAL;
1513 
1514 	if (desc->irq_data.chip == &no_irq_chip)
1515 		return -ENOSYS;
1516 	if (!try_module_get(desc->owner))
1517 		return -ENODEV;
1518 
1519 	new->irq = irq;
1520 
1521 	/*
1522 	 * If the trigger type is not specified by the caller,
1523 	 * then use the default for this interrupt.
1524 	 */
1525 	if (!(new->flags & IRQF_TRIGGER_MASK))
1526 		new->flags |= irqd_get_trigger_type(&desc->irq_data);
1527 
1528 	/*
1529 	 * Check whether the interrupt nests into another interrupt
1530 	 * thread.
1531 	 */
1532 	nested = irq_settings_is_nested_thread(desc);
1533 	if (nested) {
1534 		if (!new->thread_fn) {
1535 			ret = -EINVAL;
1536 			goto out_mput;
1537 		}
1538 		/*
1539 		 * Replace the primary handler which was provided from
1540 		 * the driver for non nested interrupt handling by the
1541 		 * dummy function which warns when called.
1542 		 */
1543 		new->handler = irq_nested_primary_handler;
1544 	} else {
1545 		if (irq_settings_can_thread(desc)) {
1546 			ret = irq_setup_forced_threading(new);
1547 			if (ret)
1548 				goto out_mput;
1549 		}
1550 	}
1551 
1552 	/*
1553 	 * Create a handler thread when a thread function is supplied
1554 	 * and the interrupt does not nest into another interrupt
1555 	 * thread.
1556 	 */
1557 	if (new->thread_fn && !nested) {
1558 		ret = setup_irq_thread(new, irq, false);
1559 		if (ret)
1560 			goto out_mput;
1561 		if (new->secondary) {
1562 			ret = setup_irq_thread(new->secondary, irq, true);
1563 			if (ret)
1564 				goto out_thread;
1565 		}
1566 	}
1567 
1568 	/*
1569 	 * Drivers are often written to work w/o knowledge about the
1570 	 * underlying irq chip implementation, so a request for a
1571 	 * threaded irq without a primary hard irq context handler
1572 	 * requires the ONESHOT flag to be set. Some irq chips like
1573 	 * MSI based interrupts are per se one shot safe. Check the
1574 	 * chip flags, so we can avoid the unmask dance at the end of
1575 	 * the threaded handler for those.
1576 	 */
1577 	if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1578 		new->flags &= ~IRQF_ONESHOT;
1579 
1580 	/*
1581 	 * Protects against a concurrent __free_irq() call which might wait
1582 	 * for synchronize_hardirq() to complete without holding the optional
1583 	 * chip bus lock and desc->lock. Also protects against handing out
1584 	 * a recycled oneshot thread_mask bit while it's still in use by
1585 	 * its previous owner.
1586 	 */
1587 	mutex_lock(&desc->request_mutex);
1588 
1589 	/*
1590 	 * Acquire bus lock as the irq_request_resources() callback below
1591 	 * might rely on the serialization or the magic power management
1592 	 * functions which are abusing the irq_bus_lock() callback,
1593 	 */
1594 	chip_bus_lock(desc);
1595 
1596 	/* First installed action requests resources. */
1597 	if (!desc->action) {
1598 		ret = irq_request_resources(desc);
1599 		if (ret) {
1600 			pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1601 			       new->name, irq, desc->irq_data.chip->name);
1602 			goto out_bus_unlock;
1603 		}
1604 	}
1605 
1606 	/*
1607 	 * The following block of code has to be executed atomically
1608 	 * protected against a concurrent interrupt and any of the other
1609 	 * management calls which are not serialized via
1610 	 * desc->request_mutex or the optional bus lock.
1611 	 */
1612 	raw_spin_lock_irqsave(&desc->lock, flags);
1613 	old_ptr = &desc->action;
1614 	old = *old_ptr;
1615 	if (old) {
1616 		/*
1617 		 * Can't share interrupts unless both agree to and are
1618 		 * the same type (level, edge, polarity). So both flag
1619 		 * fields must have IRQF_SHARED set and the bits which
1620 		 * set the trigger type must match. Also all must
1621 		 * agree on ONESHOT.
1622 		 * Interrupt lines used for NMIs cannot be shared.
1623 		 */
1624 		unsigned int oldtype;
1625 
1626 		if (desc->istate & IRQS_NMI) {
1627 			pr_err("Invalid attempt to share NMI for %s (irq %d) on irqchip %s.\n",
1628 				new->name, irq, desc->irq_data.chip->name);
1629 			ret = -EINVAL;
1630 			goto out_unlock;
1631 		}
1632 
1633 		/*
1634 		 * If nobody did set the configuration before, inherit
1635 		 * the one provided by the requester.
1636 		 */
1637 		if (irqd_trigger_type_was_set(&desc->irq_data)) {
1638 			oldtype = irqd_get_trigger_type(&desc->irq_data);
1639 		} else {
1640 			oldtype = new->flags & IRQF_TRIGGER_MASK;
1641 			irqd_set_trigger_type(&desc->irq_data, oldtype);
1642 		}
1643 
1644 		if (!((old->flags & new->flags) & IRQF_SHARED) ||
1645 		    (oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
1646 		    ((old->flags ^ new->flags) & IRQF_ONESHOT))
1647 			goto mismatch;
1648 
1649 		/* All handlers must agree on per-cpuness */
1650 		if ((old->flags & IRQF_PERCPU) !=
1651 		    (new->flags & IRQF_PERCPU))
1652 			goto mismatch;
1653 
1654 		/* add new interrupt at end of irq queue */
1655 		do {
1656 			/*
1657 			 * Or all existing action->thread_mask bits,
1658 			 * so we can find the next zero bit for this
1659 			 * new action.
1660 			 */
1661 			thread_mask |= old->thread_mask;
1662 			old_ptr = &old->next;
1663 			old = *old_ptr;
1664 		} while (old);
1665 		shared = 1;
1666 	}
1667 
1668 	/*
1669 	 * Setup the thread mask for this irqaction for ONESHOT. For
1670 	 * !ONESHOT irqs the thread mask is 0 so we can avoid a
1671 	 * conditional in irq_wake_thread().
1672 	 */
1673 	if (new->flags & IRQF_ONESHOT) {
1674 		/*
1675 		 * Unlikely to have 32 resp 64 irqs sharing one line,
1676 		 * but who knows.
1677 		 */
1678 		if (thread_mask == ~0UL) {
1679 			ret = -EBUSY;
1680 			goto out_unlock;
1681 		}
1682 		/*
1683 		 * The thread_mask for the action is or'ed to
1684 		 * desc->thread_active to indicate that the
1685 		 * IRQF_ONESHOT thread handler has been woken, but not
1686 		 * yet finished. The bit is cleared when a thread
1687 		 * completes. When all threads of a shared interrupt
1688 		 * line have completed desc->threads_active becomes
1689 		 * zero and the interrupt line is unmasked. See
1690 		 * handle.c:irq_wake_thread() for further information.
1691 		 *
1692 		 * If no thread is woken by primary (hard irq context)
1693 		 * interrupt handlers, then desc->threads_active is
1694 		 * also checked for zero to unmask the irq line in the
1695 		 * affected hard irq flow handlers
1696 		 * (handle_[fasteoi|level]_irq).
1697 		 *
1698 		 * The new action gets the first zero bit of
1699 		 * thread_mask assigned. See the loop above which or's
1700 		 * all existing action->thread_mask bits.
1701 		 */
1702 		new->thread_mask = 1UL << ffz(thread_mask);
1703 
1704 	} else if (new->handler == irq_default_primary_handler &&
1705 		   !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1706 		/*
1707 		 * The interrupt was requested with handler = NULL, so
1708 		 * we use the default primary handler for it. But it
1709 		 * does not have the oneshot flag set. In combination
1710 		 * with level interrupts this is deadly, because the
1711 		 * default primary handler just wakes the thread, then
1712 		 * the irq lines is reenabled, but the device still
1713 		 * has the level irq asserted. Rinse and repeat....
1714 		 *
1715 		 * While this works for edge type interrupts, we play
1716 		 * it safe and reject unconditionally because we can't
1717 		 * say for sure which type this interrupt really
1718 		 * has. The type flags are unreliable as the
1719 		 * underlying chip implementation can override them.
1720 		 */
1721 		pr_err("Threaded irq requested with handler=NULL and !ONESHOT for %s (irq %d)\n",
1722 		       new->name, irq);
1723 		ret = -EINVAL;
1724 		goto out_unlock;
1725 	}
1726 
1727 	if (!shared) {
1728 		/* Setup the type (level, edge polarity) if configured: */
1729 		if (new->flags & IRQF_TRIGGER_MASK) {
1730 			ret = __irq_set_trigger(desc,
1731 						new->flags & IRQF_TRIGGER_MASK);
1732 
1733 			if (ret)
1734 				goto out_unlock;
1735 		}
1736 
1737 		/*
1738 		 * Activate the interrupt. That activation must happen
1739 		 * independently of IRQ_NOAUTOEN. request_irq() can fail
1740 		 * and the callers are supposed to handle
1741 		 * that. enable_irq() of an interrupt requested with
1742 		 * IRQ_NOAUTOEN is not supposed to fail. The activation
1743 		 * keeps it in shutdown mode, it merily associates
1744 		 * resources if necessary and if that's not possible it
1745 		 * fails. Interrupts which are in managed shutdown mode
1746 		 * will simply ignore that activation request.
1747 		 */
1748 		ret = irq_activate(desc);
1749 		if (ret)
1750 			goto out_unlock;
1751 
1752 		desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1753 				  IRQS_ONESHOT | IRQS_WAITING);
1754 		irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1755 
1756 		if (new->flags & IRQF_PERCPU) {
1757 			irqd_set(&desc->irq_data, IRQD_PER_CPU);
1758 			irq_settings_set_per_cpu(desc);
1759 			if (new->flags & IRQF_NO_DEBUG)
1760 				irq_settings_set_no_debug(desc);
1761 		}
1762 
1763 		if (noirqdebug)
1764 			irq_settings_set_no_debug(desc);
1765 
1766 		if (new->flags & IRQF_ONESHOT)
1767 			desc->istate |= IRQS_ONESHOT;
1768 
1769 		/* Exclude IRQ from balancing if requested */
1770 		if (new->flags & IRQF_NOBALANCING) {
1771 			irq_settings_set_no_balancing(desc);
1772 			irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1773 		}
1774 
1775 		if (!(new->flags & IRQF_NO_AUTOEN) &&
1776 		    irq_settings_can_autoenable(desc)) {
1777 			irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
1778 		} else {
1779 			/*
1780 			 * Shared interrupts do not go well with disabling
1781 			 * auto enable. The sharing interrupt might request
1782 			 * it while it's still disabled and then wait for
1783 			 * interrupts forever.
1784 			 */
1785 			WARN_ON_ONCE(new->flags & IRQF_SHARED);
1786 			/* Undo nested disables: */
1787 			desc->depth = 1;
1788 		}
1789 
1790 	} else if (new->flags & IRQF_TRIGGER_MASK) {
1791 		unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1792 		unsigned int omsk = irqd_get_trigger_type(&desc->irq_data);
1793 
1794 		if (nmsk != omsk)
1795 			/* hope the handler works with current  trigger mode */
1796 			pr_warn("irq %d uses trigger mode %u; requested %u\n",
1797 				irq, omsk, nmsk);
1798 	}
1799 
1800 	*old_ptr = new;
1801 
1802 	irq_pm_install_action(desc, new);
1803 
1804 	/* Reset broken irq detection when installing new handler */
1805 	desc->irq_count = 0;
1806 	desc->irqs_unhandled = 0;
1807 
1808 	/*
1809 	 * Check whether we disabled the irq via the spurious handler
1810 	 * before. Reenable it and give it another chance.
1811 	 */
1812 	if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1813 		desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1814 		__enable_irq(desc);
1815 	}
1816 
1817 	raw_spin_unlock_irqrestore(&desc->lock, flags);
1818 	chip_bus_sync_unlock(desc);
1819 	mutex_unlock(&desc->request_mutex);
1820 
1821 	irq_setup_timings(desc, new);
1822 
1823 	wake_up_and_wait_for_irq_thread_ready(desc, new);
1824 	wake_up_and_wait_for_irq_thread_ready(desc, new->secondary);
1825 
1826 	register_irq_proc(irq, desc);
1827 	new->dir = NULL;
1828 	register_handler_proc(irq, new);
1829 	return 0;
1830 
1831 mismatch:
1832 	if (!(new->flags & IRQF_PROBE_SHARED)) {
1833 		pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1834 		       irq, new->flags, new->name, old->flags, old->name);
1835 #ifdef CONFIG_DEBUG_SHIRQ
1836 		dump_stack();
1837 #endif
1838 	}
1839 	ret = -EBUSY;
1840 
1841 out_unlock:
1842 	raw_spin_unlock_irqrestore(&desc->lock, flags);
1843 
1844 	if (!desc->action)
1845 		irq_release_resources(desc);
1846 out_bus_unlock:
1847 	chip_bus_sync_unlock(desc);
1848 	mutex_unlock(&desc->request_mutex);
1849 
1850 out_thread:
1851 	if (new->thread) {
1852 		struct task_struct *t = new->thread;
1853 
1854 		new->thread = NULL;
1855 		kthread_stop(t);
1856 		put_task_struct(t);
1857 	}
1858 	if (new->secondary && new->secondary->thread) {
1859 		struct task_struct *t = new->secondary->thread;
1860 
1861 		new->secondary->thread = NULL;
1862 		kthread_stop(t);
1863 		put_task_struct(t);
1864 	}
1865 out_mput:
1866 	module_put(desc->owner);
1867 	return ret;
1868 }
1869 
1870 /*
1871  * Internal function to unregister an irqaction - used to free
1872  * regular and special interrupts that are part of the architecture.
1873  */
__free_irq(struct irq_desc * desc,void * dev_id)1874 static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
1875 {
1876 	unsigned irq = desc->irq_data.irq;
1877 	struct irqaction *action, **action_ptr;
1878 	unsigned long flags;
1879 
1880 	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1881 
1882 	mutex_lock(&desc->request_mutex);
1883 	chip_bus_lock(desc);
1884 	raw_spin_lock_irqsave(&desc->lock, flags);
1885 
1886 	/*
1887 	 * There can be multiple actions per IRQ descriptor, find the right
1888 	 * one based on the dev_id:
1889 	 */
1890 	action_ptr = &desc->action;
1891 	for (;;) {
1892 		action = *action_ptr;
1893 
1894 		if (!action) {
1895 			WARN(1, "Trying to free already-free IRQ %d\n", irq);
1896 			raw_spin_unlock_irqrestore(&desc->lock, flags);
1897 			chip_bus_sync_unlock(desc);
1898 			mutex_unlock(&desc->request_mutex);
1899 			return NULL;
1900 		}
1901 
1902 		if (action->dev_id == dev_id)
1903 			break;
1904 		action_ptr = &action->next;
1905 	}
1906 
1907 	/* Found it - now remove it from the list of entries: */
1908 	*action_ptr = action->next;
1909 
1910 	irq_pm_remove_action(desc, action);
1911 
1912 	/* If this was the last handler, shut down the IRQ line: */
1913 	if (!desc->action) {
1914 		irq_settings_clr_disable_unlazy(desc);
1915 		/* Only shutdown. Deactivate after synchronize_hardirq() */
1916 		irq_shutdown(desc);
1917 	}
1918 
1919 #ifdef CONFIG_SMP
1920 	/* make sure affinity_hint is cleaned up */
1921 	if (WARN_ON_ONCE(desc->affinity_hint))
1922 		desc->affinity_hint = NULL;
1923 #endif
1924 
1925 	raw_spin_unlock_irqrestore(&desc->lock, flags);
1926 	/*
1927 	 * Drop bus_lock here so the changes which were done in the chip
1928 	 * callbacks above are synced out to the irq chips which hang
1929 	 * behind a slow bus (I2C, SPI) before calling synchronize_hardirq().
1930 	 *
1931 	 * Aside of that the bus_lock can also be taken from the threaded
1932 	 * handler in irq_finalize_oneshot() which results in a deadlock
1933 	 * because kthread_stop() would wait forever for the thread to
1934 	 * complete, which is blocked on the bus lock.
1935 	 *
1936 	 * The still held desc->request_mutex() protects against a
1937 	 * concurrent request_irq() of this irq so the release of resources
1938 	 * and timing data is properly serialized.
1939 	 */
1940 	chip_bus_sync_unlock(desc);
1941 
1942 	unregister_handler_proc(irq, action);
1943 
1944 	/*
1945 	 * Make sure it's not being used on another CPU and if the chip
1946 	 * supports it also make sure that there is no (not yet serviced)
1947 	 * interrupt in flight at the hardware level.
1948 	 */
1949 	__synchronize_irq(desc);
1950 
1951 #ifdef CONFIG_DEBUG_SHIRQ
1952 	/*
1953 	 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1954 	 * event to happen even now it's being freed, so let's make sure that
1955 	 * is so by doing an extra call to the handler ....
1956 	 *
1957 	 * ( We do this after actually deregistering it, to make sure that a
1958 	 *   'real' IRQ doesn't run in parallel with our fake. )
1959 	 */
1960 	if (action->flags & IRQF_SHARED) {
1961 		local_irq_save(flags);
1962 		action->handler(irq, dev_id);
1963 		local_irq_restore(flags);
1964 	}
1965 #endif
1966 
1967 	/*
1968 	 * The action has already been removed above, but the thread writes
1969 	 * its oneshot mask bit when it completes. Though request_mutex is
1970 	 * held across this which prevents __setup_irq() from handing out
1971 	 * the same bit to a newly requested action.
1972 	 */
1973 	if (action->thread) {
1974 		kthread_stop(action->thread);
1975 		put_task_struct(action->thread);
1976 		if (action->secondary && action->secondary->thread) {
1977 			kthread_stop(action->secondary->thread);
1978 			put_task_struct(action->secondary->thread);
1979 		}
1980 	}
1981 
1982 	/* Last action releases resources */
1983 	if (!desc->action) {
1984 		/*
1985 		 * Reacquire bus lock as irq_release_resources() might
1986 		 * require it to deallocate resources over the slow bus.
1987 		 */
1988 		chip_bus_lock(desc);
1989 		/*
1990 		 * There is no interrupt on the fly anymore. Deactivate it
1991 		 * completely.
1992 		 */
1993 		raw_spin_lock_irqsave(&desc->lock, flags);
1994 		irq_domain_deactivate_irq(&desc->irq_data);
1995 		raw_spin_unlock_irqrestore(&desc->lock, flags);
1996 
1997 		irq_release_resources(desc);
1998 		chip_bus_sync_unlock(desc);
1999 		irq_remove_timings(desc);
2000 	}
2001 
2002 	mutex_unlock(&desc->request_mutex);
2003 
2004 	irq_chip_pm_put(&desc->irq_data);
2005 	module_put(desc->owner);
2006 	kfree(action->secondary);
2007 	return action;
2008 }
2009 
2010 /**
2011  *	free_irq - free an interrupt allocated with request_irq
2012  *	@irq: Interrupt line to free
2013  *	@dev_id: Device identity to free
2014  *
2015  *	Remove an interrupt handler. The handler is removed and if the
2016  *	interrupt line is no longer in use by any driver it is disabled.
2017  *	On a shared IRQ the caller must ensure the interrupt is disabled
2018  *	on the card it drives before calling this function. The function
2019  *	does not return until any executing interrupts for this IRQ
2020  *	have completed.
2021  *
2022  *	This function must not be called from interrupt context.
2023  *
2024  *	Returns the devname argument passed to request_irq.
2025  */
free_irq(unsigned int irq,void * dev_id)2026 const void *free_irq(unsigned int irq, void *dev_id)
2027 {
2028 	struct irq_desc *desc = irq_to_desc(irq);
2029 	struct irqaction *action;
2030 	const char *devname;
2031 
2032 	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
2033 		return NULL;
2034 
2035 #ifdef CONFIG_SMP
2036 	if (WARN_ON(desc->affinity_notify))
2037 		desc->affinity_notify = NULL;
2038 #endif
2039 
2040 	action = __free_irq(desc, dev_id);
2041 
2042 	if (!action)
2043 		return NULL;
2044 
2045 	devname = action->name;
2046 	kfree(action);
2047 	return devname;
2048 }
2049 EXPORT_SYMBOL(free_irq);
2050 
2051 /* This function must be called with desc->lock held */
__cleanup_nmi(unsigned int irq,struct irq_desc * desc)2052 static const void *__cleanup_nmi(unsigned int irq, struct irq_desc *desc)
2053 {
2054 	const char *devname = NULL;
2055 
2056 	desc->istate &= ~IRQS_NMI;
2057 
2058 	if (!WARN_ON(desc->action == NULL)) {
2059 		irq_pm_remove_action(desc, desc->action);
2060 		devname = desc->action->name;
2061 		unregister_handler_proc(irq, desc->action);
2062 
2063 		kfree(desc->action);
2064 		desc->action = NULL;
2065 	}
2066 
2067 	irq_settings_clr_disable_unlazy(desc);
2068 	irq_shutdown_and_deactivate(desc);
2069 
2070 	irq_release_resources(desc);
2071 
2072 	irq_chip_pm_put(&desc->irq_data);
2073 	module_put(desc->owner);
2074 
2075 	return devname;
2076 }
2077 
free_nmi(unsigned int irq,void * dev_id)2078 const void *free_nmi(unsigned int irq, void *dev_id)
2079 {
2080 	struct irq_desc *desc = irq_to_desc(irq);
2081 	unsigned long flags;
2082 	const void *devname;
2083 
2084 	if (!desc || WARN_ON(!(desc->istate & IRQS_NMI)))
2085 		return NULL;
2086 
2087 	if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
2088 		return NULL;
2089 
2090 	/* NMI still enabled */
2091 	if (WARN_ON(desc->depth == 0))
2092 		disable_nmi_nosync(irq);
2093 
2094 	raw_spin_lock_irqsave(&desc->lock, flags);
2095 
2096 	irq_nmi_teardown(desc);
2097 	devname = __cleanup_nmi(irq, desc);
2098 
2099 	raw_spin_unlock_irqrestore(&desc->lock, flags);
2100 
2101 	return devname;
2102 }
2103 
2104 /**
2105  *	request_threaded_irq - allocate an interrupt line
2106  *	@irq: Interrupt line to allocate
2107  *	@handler: Function to be called when the IRQ occurs.
2108  *		  Primary handler for threaded interrupts.
2109  *		  If handler is NULL and thread_fn != NULL
2110  *		  the default primary handler is installed.
2111  *	@thread_fn: Function called from the irq handler thread
2112  *		    If NULL, no irq thread is created
2113  *	@irqflags: Interrupt type flags
2114  *	@devname: An ascii name for the claiming device
2115  *	@dev_id: A cookie passed back to the handler function
2116  *
2117  *	This call allocates interrupt resources and enables the
2118  *	interrupt line and IRQ handling. From the point this
2119  *	call is made your handler function may be invoked. Since
2120  *	your handler function must clear any interrupt the board
2121  *	raises, you must take care both to initialise your hardware
2122  *	and to set up the interrupt handler in the right order.
2123  *
2124  *	If you want to set up a threaded irq handler for your device
2125  *	then you need to supply @handler and @thread_fn. @handler is
2126  *	still called in hard interrupt context and has to check
2127  *	whether the interrupt originates from the device. If yes it
2128  *	needs to disable the interrupt on the device and return
2129  *	IRQ_WAKE_THREAD which will wake up the handler thread and run
2130  *	@thread_fn. This split handler design is necessary to support
2131  *	shared interrupts.
2132  *
2133  *	Dev_id must be globally unique. Normally the address of the
2134  *	device data structure is used as the cookie. Since the handler
2135  *	receives this value it makes sense to use it.
2136  *
2137  *	If your interrupt is shared you must pass a non NULL dev_id
2138  *	as this is required when freeing the interrupt.
2139  *
2140  *	Flags:
2141  *
2142  *	IRQF_SHARED		Interrupt is shared
2143  *	IRQF_TRIGGER_*		Specify active edge(s) or level
2144  *	IRQF_ONESHOT		Run thread_fn with interrupt line masked
2145  */
request_threaded_irq(unsigned int irq,irq_handler_t handler,irq_handler_t thread_fn,unsigned long irqflags,const char * devname,void * dev_id)2146 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
2147 			 irq_handler_t thread_fn, unsigned long irqflags,
2148 			 const char *devname, void *dev_id)
2149 {
2150 	struct irqaction *action;
2151 	struct irq_desc *desc;
2152 	int retval;
2153 
2154 	if (irq == IRQ_NOTCONNECTED)
2155 		return -ENOTCONN;
2156 
2157 	/*
2158 	 * Sanity-check: shared interrupts must pass in a real dev-ID,
2159 	 * otherwise we'll have trouble later trying to figure out
2160 	 * which interrupt is which (messes up the interrupt freeing
2161 	 * logic etc).
2162 	 *
2163 	 * Also shared interrupts do not go well with disabling auto enable.
2164 	 * The sharing interrupt might request it while it's still disabled
2165 	 * and then wait for interrupts forever.
2166 	 *
2167 	 * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
2168 	 * it cannot be set along with IRQF_NO_SUSPEND.
2169 	 */
2170 	if (((irqflags & IRQF_SHARED) && !dev_id) ||
2171 	    ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) ||
2172 	    (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
2173 	    ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
2174 		return -EINVAL;
2175 
2176 	desc = irq_to_desc(irq);
2177 	if (!desc)
2178 		return -EINVAL;
2179 
2180 	if (!irq_settings_can_request(desc) ||
2181 	    WARN_ON(irq_settings_is_per_cpu_devid(desc)))
2182 		return -EINVAL;
2183 
2184 	if (!handler) {
2185 		if (!thread_fn)
2186 			return -EINVAL;
2187 		handler = irq_default_primary_handler;
2188 	}
2189 
2190 	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2191 	if (!action)
2192 		return -ENOMEM;
2193 
2194 	action->handler = handler;
2195 	action->thread_fn = thread_fn;
2196 	action->flags = irqflags;
2197 	action->name = devname;
2198 	action->dev_id = dev_id;
2199 
2200 	retval = irq_chip_pm_get(&desc->irq_data);
2201 	if (retval < 0) {
2202 		kfree(action);
2203 		return retval;
2204 	}
2205 
2206 	retval = __setup_irq(irq, desc, action);
2207 
2208 	if (retval) {
2209 		irq_chip_pm_put(&desc->irq_data);
2210 		kfree(action->secondary);
2211 		kfree(action);
2212 	}
2213 
2214 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
2215 	if (!retval && (irqflags & IRQF_SHARED)) {
2216 		/*
2217 		 * It's a shared IRQ -- the driver ought to be prepared for it
2218 		 * to happen immediately, so let's make sure....
2219 		 * We disable the irq to make sure that a 'real' IRQ doesn't
2220 		 * run in parallel with our fake.
2221 		 */
2222 		unsigned long flags;
2223 
2224 		disable_irq(irq);
2225 		local_irq_save(flags);
2226 
2227 		handler(irq, dev_id);
2228 
2229 		local_irq_restore(flags);
2230 		enable_irq(irq);
2231 	}
2232 #endif
2233 	return retval;
2234 }
2235 EXPORT_SYMBOL(request_threaded_irq);
2236 
2237 /**
2238  *	request_any_context_irq - allocate an interrupt line
2239  *	@irq: Interrupt line to allocate
2240  *	@handler: Function to be called when the IRQ occurs.
2241  *		  Threaded handler for threaded interrupts.
2242  *	@flags: Interrupt type flags
2243  *	@name: An ascii name for the claiming device
2244  *	@dev_id: A cookie passed back to the handler function
2245  *
2246  *	This call allocates interrupt resources and enables the
2247  *	interrupt line and IRQ handling. It selects either a
2248  *	hardirq or threaded handling method depending on the
2249  *	context.
2250  *
2251  *	On failure, it returns a negative value. On success,
2252  *	it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
2253  */
request_any_context_irq(unsigned int irq,irq_handler_t handler,unsigned long flags,const char * name,void * dev_id)2254 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
2255 			    unsigned long flags, const char *name, void *dev_id)
2256 {
2257 	struct irq_desc *desc;
2258 	int ret;
2259 
2260 	if (irq == IRQ_NOTCONNECTED)
2261 		return -ENOTCONN;
2262 
2263 	desc = irq_to_desc(irq);
2264 	if (!desc)
2265 		return -EINVAL;
2266 
2267 	if (irq_settings_is_nested_thread(desc)) {
2268 		ret = request_threaded_irq(irq, NULL, handler,
2269 					   flags, name, dev_id);
2270 		return !ret ? IRQC_IS_NESTED : ret;
2271 	}
2272 
2273 	ret = request_irq(irq, handler, flags, name, dev_id);
2274 	return !ret ? IRQC_IS_HARDIRQ : ret;
2275 }
2276 EXPORT_SYMBOL_GPL(request_any_context_irq);
2277 
2278 /**
2279  *	request_nmi - allocate an interrupt line for NMI delivery
2280  *	@irq: Interrupt line to allocate
2281  *	@handler: Function to be called when the IRQ occurs.
2282  *		  Threaded handler for threaded interrupts.
2283  *	@irqflags: Interrupt type flags
2284  *	@name: An ascii name for the claiming device
2285  *	@dev_id: A cookie passed back to the handler function
2286  *
2287  *	This call allocates interrupt resources and enables the
2288  *	interrupt line and IRQ handling. It sets up the IRQ line
2289  *	to be handled as an NMI.
2290  *
2291  *	An interrupt line delivering NMIs cannot be shared and IRQ handling
2292  *	cannot be threaded.
2293  *
2294  *	Interrupt lines requested for NMI delivering must produce per cpu
2295  *	interrupts and have auto enabling setting disabled.
2296  *
2297  *	Dev_id must be globally unique. Normally the address of the
2298  *	device data structure is used as the cookie. Since the handler
2299  *	receives this value it makes sense to use it.
2300  *
2301  *	If the interrupt line cannot be used to deliver NMIs, function
2302  *	will fail and return a negative value.
2303  */
request_nmi(unsigned int irq,irq_handler_t handler,unsigned long irqflags,const char * name,void * dev_id)2304 int request_nmi(unsigned int irq, irq_handler_t handler,
2305 		unsigned long irqflags, const char *name, void *dev_id)
2306 {
2307 	struct irqaction *action;
2308 	struct irq_desc *desc;
2309 	unsigned long flags;
2310 	int retval;
2311 
2312 	if (irq == IRQ_NOTCONNECTED)
2313 		return -ENOTCONN;
2314 
2315 	/* NMI cannot be shared, used for Polling */
2316 	if (irqflags & (IRQF_SHARED | IRQF_COND_SUSPEND | IRQF_IRQPOLL))
2317 		return -EINVAL;
2318 
2319 	if (!(irqflags & IRQF_PERCPU))
2320 		return -EINVAL;
2321 
2322 	if (!handler)
2323 		return -EINVAL;
2324 
2325 	desc = irq_to_desc(irq);
2326 
2327 	if (!desc || (irq_settings_can_autoenable(desc) &&
2328 	    !(irqflags & IRQF_NO_AUTOEN)) ||
2329 	    !irq_settings_can_request(desc) ||
2330 	    WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
2331 	    !irq_supports_nmi(desc))
2332 		return -EINVAL;
2333 
2334 	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2335 	if (!action)
2336 		return -ENOMEM;
2337 
2338 	action->handler = handler;
2339 	action->flags = irqflags | IRQF_NO_THREAD | IRQF_NOBALANCING;
2340 	action->name = name;
2341 	action->dev_id = dev_id;
2342 
2343 	retval = irq_chip_pm_get(&desc->irq_data);
2344 	if (retval < 0)
2345 		goto err_out;
2346 
2347 	retval = __setup_irq(irq, desc, action);
2348 	if (retval)
2349 		goto err_irq_setup;
2350 
2351 	raw_spin_lock_irqsave(&desc->lock, flags);
2352 
2353 	/* Setup NMI state */
2354 	desc->istate |= IRQS_NMI;
2355 	retval = irq_nmi_setup(desc);
2356 	if (retval) {
2357 		__cleanup_nmi(irq, desc);
2358 		raw_spin_unlock_irqrestore(&desc->lock, flags);
2359 		return -EINVAL;
2360 	}
2361 
2362 	raw_spin_unlock_irqrestore(&desc->lock, flags);
2363 
2364 	return 0;
2365 
2366 err_irq_setup:
2367 	irq_chip_pm_put(&desc->irq_data);
2368 err_out:
2369 	kfree(action);
2370 
2371 	return retval;
2372 }
2373 
enable_percpu_irq(unsigned int irq,unsigned int type)2374 void enable_percpu_irq(unsigned int irq, unsigned int type)
2375 {
2376 	unsigned int cpu = smp_processor_id();
2377 	unsigned long flags;
2378 	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2379 
2380 	if (!desc)
2381 		return;
2382 
2383 	/*
2384 	 * If the trigger type is not specified by the caller, then
2385 	 * use the default for this interrupt.
2386 	 */
2387 	type &= IRQ_TYPE_SENSE_MASK;
2388 	if (type == IRQ_TYPE_NONE)
2389 		type = irqd_get_trigger_type(&desc->irq_data);
2390 
2391 	if (type != IRQ_TYPE_NONE) {
2392 		int ret;
2393 
2394 		ret = __irq_set_trigger(desc, type);
2395 
2396 		if (ret) {
2397 			WARN(1, "failed to set type for IRQ%d\n", irq);
2398 			goto out;
2399 		}
2400 	}
2401 
2402 	irq_percpu_enable(desc, cpu);
2403 out:
2404 	irq_put_desc_unlock(desc, flags);
2405 }
2406 EXPORT_SYMBOL_GPL(enable_percpu_irq);
2407 
enable_percpu_nmi(unsigned int irq,unsigned int type)2408 void enable_percpu_nmi(unsigned int irq, unsigned int type)
2409 {
2410 	enable_percpu_irq(irq, type);
2411 }
2412 
2413 /**
2414  * irq_percpu_is_enabled - Check whether the per cpu irq is enabled
2415  * @irq:	Linux irq number to check for
2416  *
2417  * Must be called from a non migratable context. Returns the enable
2418  * state of a per cpu interrupt on the current cpu.
2419  */
irq_percpu_is_enabled(unsigned int irq)2420 bool irq_percpu_is_enabled(unsigned int irq)
2421 {
2422 	unsigned int cpu = smp_processor_id();
2423 	struct irq_desc *desc;
2424 	unsigned long flags;
2425 	bool is_enabled;
2426 
2427 	desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2428 	if (!desc)
2429 		return false;
2430 
2431 	is_enabled = cpumask_test_cpu(cpu, desc->percpu_enabled);
2432 	irq_put_desc_unlock(desc, flags);
2433 
2434 	return is_enabled;
2435 }
2436 EXPORT_SYMBOL_GPL(irq_percpu_is_enabled);
2437 
disable_percpu_irq(unsigned int irq)2438 void disable_percpu_irq(unsigned int irq)
2439 {
2440 	unsigned int cpu = smp_processor_id();
2441 	unsigned long flags;
2442 	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2443 
2444 	if (!desc)
2445 		return;
2446 
2447 	irq_percpu_disable(desc, cpu);
2448 	irq_put_desc_unlock(desc, flags);
2449 }
2450 EXPORT_SYMBOL_GPL(disable_percpu_irq);
2451 
disable_percpu_nmi(unsigned int irq)2452 void disable_percpu_nmi(unsigned int irq)
2453 {
2454 	disable_percpu_irq(irq);
2455 }
2456 
2457 /*
2458  * Internal function to unregister a percpu irqaction.
2459  */
__free_percpu_irq(unsigned int irq,void __percpu * dev_id)2460 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
2461 {
2462 	struct irq_desc *desc = irq_to_desc(irq);
2463 	struct irqaction *action;
2464 	unsigned long flags;
2465 
2466 	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
2467 
2468 	if (!desc)
2469 		return NULL;
2470 
2471 	raw_spin_lock_irqsave(&desc->lock, flags);
2472 
2473 	action = desc->action;
2474 	if (!action || action->percpu_dev_id != dev_id) {
2475 		WARN(1, "Trying to free already-free IRQ %d\n", irq);
2476 		goto bad;
2477 	}
2478 
2479 	if (!cpumask_empty(desc->percpu_enabled)) {
2480 		WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
2481 		     irq, cpumask_first(desc->percpu_enabled));
2482 		goto bad;
2483 	}
2484 
2485 	/* Found it - now remove it from the list of entries: */
2486 	desc->action = NULL;
2487 
2488 	desc->istate &= ~IRQS_NMI;
2489 
2490 	raw_spin_unlock_irqrestore(&desc->lock, flags);
2491 
2492 	unregister_handler_proc(irq, action);
2493 
2494 	irq_chip_pm_put(&desc->irq_data);
2495 	module_put(desc->owner);
2496 	return action;
2497 
2498 bad:
2499 	raw_spin_unlock_irqrestore(&desc->lock, flags);
2500 	return NULL;
2501 }
2502 
2503 /**
2504  *	remove_percpu_irq - free a per-cpu interrupt
2505  *	@irq: Interrupt line to free
2506  *	@act: irqaction for the interrupt
2507  *
2508  * Used to remove interrupts statically setup by the early boot process.
2509  */
remove_percpu_irq(unsigned int irq,struct irqaction * act)2510 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
2511 {
2512 	struct irq_desc *desc = irq_to_desc(irq);
2513 
2514 	if (desc && irq_settings_is_per_cpu_devid(desc))
2515 	    __free_percpu_irq(irq, act->percpu_dev_id);
2516 }
2517 
2518 /**
2519  *	free_percpu_irq - free an interrupt allocated with request_percpu_irq
2520  *	@irq: Interrupt line to free
2521  *	@dev_id: Device identity to free
2522  *
2523  *	Remove a percpu interrupt handler. The handler is removed, but
2524  *	the interrupt line is not disabled. This must be done on each
2525  *	CPU before calling this function. The function does not return
2526  *	until any executing interrupts for this IRQ have completed.
2527  *
2528  *	This function must not be called from interrupt context.
2529  */
free_percpu_irq(unsigned int irq,void __percpu * dev_id)2530 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
2531 {
2532 	struct irq_desc *desc = irq_to_desc(irq);
2533 
2534 	if (!desc || !irq_settings_is_per_cpu_devid(desc))
2535 		return;
2536 
2537 	chip_bus_lock(desc);
2538 	kfree(__free_percpu_irq(irq, dev_id));
2539 	chip_bus_sync_unlock(desc);
2540 }
2541 EXPORT_SYMBOL_GPL(free_percpu_irq);
2542 
free_percpu_nmi(unsigned int irq,void __percpu * dev_id)2543 void free_percpu_nmi(unsigned int irq, void __percpu *dev_id)
2544 {
2545 	struct irq_desc *desc = irq_to_desc(irq);
2546 
2547 	if (!desc || !irq_settings_is_per_cpu_devid(desc))
2548 		return;
2549 
2550 	if (WARN_ON(!(desc->istate & IRQS_NMI)))
2551 		return;
2552 
2553 	kfree(__free_percpu_irq(irq, dev_id));
2554 }
2555 
2556 /**
2557  *	setup_percpu_irq - setup a per-cpu interrupt
2558  *	@irq: Interrupt line to setup
2559  *	@act: irqaction for the interrupt
2560  *
2561  * Used to statically setup per-cpu interrupts in the early boot process.
2562  */
setup_percpu_irq(unsigned int irq,struct irqaction * act)2563 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
2564 {
2565 	struct irq_desc *desc = irq_to_desc(irq);
2566 	int retval;
2567 
2568 	if (!desc || !irq_settings_is_per_cpu_devid(desc))
2569 		return -EINVAL;
2570 
2571 	retval = irq_chip_pm_get(&desc->irq_data);
2572 	if (retval < 0)
2573 		return retval;
2574 
2575 	retval = __setup_irq(irq, desc, act);
2576 
2577 	if (retval)
2578 		irq_chip_pm_put(&desc->irq_data);
2579 
2580 	return retval;
2581 }
2582 
2583 /**
2584  *	__request_percpu_irq - allocate a percpu interrupt line
2585  *	@irq: Interrupt line to allocate
2586  *	@handler: Function to be called when the IRQ occurs.
2587  *	@flags: Interrupt type flags (IRQF_TIMER only)
2588  *	@devname: An ascii name for the claiming device
2589  *	@dev_id: A percpu cookie passed back to the handler function
2590  *
2591  *	This call allocates interrupt resources and enables the
2592  *	interrupt on the local CPU. If the interrupt is supposed to be
2593  *	enabled on other CPUs, it has to be done on each CPU using
2594  *	enable_percpu_irq().
2595  *
2596  *	Dev_id must be globally unique. It is a per-cpu variable, and
2597  *	the handler gets called with the interrupted CPU's instance of
2598  *	that variable.
2599  */
__request_percpu_irq(unsigned int irq,irq_handler_t handler,unsigned long flags,const char * devname,void __percpu * dev_id)2600 int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
2601 			 unsigned long flags, const char *devname,
2602 			 void __percpu *dev_id)
2603 {
2604 	struct irqaction *action;
2605 	struct irq_desc *desc;
2606 	int retval;
2607 
2608 	if (!dev_id)
2609 		return -EINVAL;
2610 
2611 	desc = irq_to_desc(irq);
2612 	if (!desc || !irq_settings_can_request(desc) ||
2613 	    !irq_settings_is_per_cpu_devid(desc))
2614 		return -EINVAL;
2615 
2616 	if (flags && flags != IRQF_TIMER)
2617 		return -EINVAL;
2618 
2619 	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2620 	if (!action)
2621 		return -ENOMEM;
2622 
2623 	action->handler = handler;
2624 	action->flags = flags | IRQF_PERCPU | IRQF_NO_SUSPEND;
2625 	action->name = devname;
2626 	action->percpu_dev_id = dev_id;
2627 
2628 	retval = irq_chip_pm_get(&desc->irq_data);
2629 	if (retval < 0) {
2630 		kfree(action);
2631 		return retval;
2632 	}
2633 
2634 	retval = __setup_irq(irq, desc, action);
2635 
2636 	if (retval) {
2637 		irq_chip_pm_put(&desc->irq_data);
2638 		kfree(action);
2639 	}
2640 
2641 	return retval;
2642 }
2643 EXPORT_SYMBOL_GPL(__request_percpu_irq);
2644 
2645 /**
2646  *	request_percpu_nmi - allocate a percpu interrupt line for NMI delivery
2647  *	@irq: Interrupt line to allocate
2648  *	@handler: Function to be called when the IRQ occurs.
2649  *	@name: An ascii name for the claiming device
2650  *	@dev_id: A percpu cookie passed back to the handler function
2651  *
2652  *	This call allocates interrupt resources for a per CPU NMI. Per CPU NMIs
2653  *	have to be setup on each CPU by calling prepare_percpu_nmi() before
2654  *	being enabled on the same CPU by using enable_percpu_nmi().
2655  *
2656  *	Dev_id must be globally unique. It is a per-cpu variable, and
2657  *	the handler gets called with the interrupted CPU's instance of
2658  *	that variable.
2659  *
2660  *	Interrupt lines requested for NMI delivering should have auto enabling
2661  *	setting disabled.
2662  *
2663  *	If the interrupt line cannot be used to deliver NMIs, function
2664  *	will fail returning a negative value.
2665  */
request_percpu_nmi(unsigned int irq,irq_handler_t handler,const char * name,void __percpu * dev_id)2666 int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
2667 		       const char *name, void __percpu *dev_id)
2668 {
2669 	struct irqaction *action;
2670 	struct irq_desc *desc;
2671 	unsigned long flags;
2672 	int retval;
2673 
2674 	if (!handler)
2675 		return -EINVAL;
2676 
2677 	desc = irq_to_desc(irq);
2678 
2679 	if (!desc || !irq_settings_can_request(desc) ||
2680 	    !irq_settings_is_per_cpu_devid(desc) ||
2681 	    irq_settings_can_autoenable(desc) ||
2682 	    !irq_supports_nmi(desc))
2683 		return -EINVAL;
2684 
2685 	/* The line cannot already be NMI */
2686 	if (desc->istate & IRQS_NMI)
2687 		return -EINVAL;
2688 
2689 	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2690 	if (!action)
2691 		return -ENOMEM;
2692 
2693 	action->handler = handler;
2694 	action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND | IRQF_NO_THREAD
2695 		| IRQF_NOBALANCING;
2696 	action->name = name;
2697 	action->percpu_dev_id = dev_id;
2698 
2699 	retval = irq_chip_pm_get(&desc->irq_data);
2700 	if (retval < 0)
2701 		goto err_out;
2702 
2703 	retval = __setup_irq(irq, desc, action);
2704 	if (retval)
2705 		goto err_irq_setup;
2706 
2707 	raw_spin_lock_irqsave(&desc->lock, flags);
2708 	desc->istate |= IRQS_NMI;
2709 	raw_spin_unlock_irqrestore(&desc->lock, flags);
2710 
2711 	return 0;
2712 
2713 err_irq_setup:
2714 	irq_chip_pm_put(&desc->irq_data);
2715 err_out:
2716 	kfree(action);
2717 
2718 	return retval;
2719 }
2720 
2721 /**
2722  *	prepare_percpu_nmi - performs CPU local setup for NMI delivery
2723  *	@irq: Interrupt line to prepare for NMI delivery
2724  *
2725  *	This call prepares an interrupt line to deliver NMI on the current CPU,
2726  *	before that interrupt line gets enabled with enable_percpu_nmi().
2727  *
2728  *	As a CPU local operation, this should be called from non-preemptible
2729  *	context.
2730  *
2731  *	If the interrupt line cannot be used to deliver NMIs, function
2732  *	will fail returning a negative value.
2733  */
prepare_percpu_nmi(unsigned int irq)2734 int prepare_percpu_nmi(unsigned int irq)
2735 {
2736 	unsigned long flags;
2737 	struct irq_desc *desc;
2738 	int ret = 0;
2739 
2740 	WARN_ON(preemptible());
2741 
2742 	desc = irq_get_desc_lock(irq, &flags,
2743 				 IRQ_GET_DESC_CHECK_PERCPU);
2744 	if (!desc)
2745 		return -EINVAL;
2746 
2747 	if (WARN(!(desc->istate & IRQS_NMI),
2748 		 KERN_ERR "prepare_percpu_nmi called for a non-NMI interrupt: irq %u\n",
2749 		 irq)) {
2750 		ret = -EINVAL;
2751 		goto out;
2752 	}
2753 
2754 	ret = irq_nmi_setup(desc);
2755 	if (ret) {
2756 		pr_err("Failed to setup NMI delivery: irq %u\n", irq);
2757 		goto out;
2758 	}
2759 
2760 out:
2761 	irq_put_desc_unlock(desc, flags);
2762 	return ret;
2763 }
2764 
2765 /**
2766  *	teardown_percpu_nmi - undoes NMI setup of IRQ line
2767  *	@irq: Interrupt line from which CPU local NMI configuration should be
2768  *	      removed
2769  *
2770  *	This call undoes the setup done by prepare_percpu_nmi().
2771  *
2772  *	IRQ line should not be enabled for the current CPU.
2773  *
2774  *	As a CPU local operation, this should be called from non-preemptible
2775  *	context.
2776  */
teardown_percpu_nmi(unsigned int irq)2777 void teardown_percpu_nmi(unsigned int irq)
2778 {
2779 	unsigned long flags;
2780 	struct irq_desc *desc;
2781 
2782 	WARN_ON(preemptible());
2783 
2784 	desc = irq_get_desc_lock(irq, &flags,
2785 				 IRQ_GET_DESC_CHECK_PERCPU);
2786 	if (!desc)
2787 		return;
2788 
2789 	if (WARN_ON(!(desc->istate & IRQS_NMI)))
2790 		goto out;
2791 
2792 	irq_nmi_teardown(desc);
2793 out:
2794 	irq_put_desc_unlock(desc, flags);
2795 }
2796 
__irq_get_irqchip_state(struct irq_data * data,enum irqchip_irq_state which,bool * state)2797 int __irq_get_irqchip_state(struct irq_data *data, enum irqchip_irq_state which,
2798 			    bool *state)
2799 {
2800 	struct irq_chip *chip;
2801 	int err = -EINVAL;
2802 
2803 	do {
2804 		chip = irq_data_get_irq_chip(data);
2805 		if (WARN_ON_ONCE(!chip))
2806 			return -ENODEV;
2807 		if (chip->irq_get_irqchip_state)
2808 			break;
2809 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
2810 		data = data->parent_data;
2811 #else
2812 		data = NULL;
2813 #endif
2814 	} while (data);
2815 
2816 	if (data)
2817 		err = chip->irq_get_irqchip_state(data, which, state);
2818 	return err;
2819 }
2820 
2821 /**
2822  *	irq_get_irqchip_state - returns the irqchip state of a interrupt.
2823  *	@irq: Interrupt line that is forwarded to a VM
2824  *	@which: One of IRQCHIP_STATE_* the caller wants to know about
2825  *	@state: a pointer to a boolean where the state is to be stored
2826  *
2827  *	This call snapshots the internal irqchip state of an
2828  *	interrupt, returning into @state the bit corresponding to
2829  *	stage @which
2830  *
2831  *	This function should be called with preemption disabled if the
2832  *	interrupt controller has per-cpu registers.
2833  */
irq_get_irqchip_state(unsigned int irq,enum irqchip_irq_state which,bool * state)2834 int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
2835 			  bool *state)
2836 {
2837 	struct irq_desc *desc;
2838 	struct irq_data *data;
2839 	unsigned long flags;
2840 	int err = -EINVAL;
2841 
2842 	desc = irq_get_desc_buslock(irq, &flags, 0);
2843 	if (!desc)
2844 		return err;
2845 
2846 	data = irq_desc_get_irq_data(desc);
2847 
2848 	err = __irq_get_irqchip_state(data, which, state);
2849 
2850 	irq_put_desc_busunlock(desc, flags);
2851 	return err;
2852 }
2853 EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
2854 
2855 /**
2856  *	irq_set_irqchip_state - set the state of a forwarded interrupt.
2857  *	@irq: Interrupt line that is forwarded to a VM
2858  *	@which: State to be restored (one of IRQCHIP_STATE_*)
2859  *	@val: Value corresponding to @which
2860  *
2861  *	This call sets the internal irqchip state of an interrupt,
2862  *	depending on the value of @which.
2863  *
2864  *	This function should be called with migration disabled if the
2865  *	interrupt controller has per-cpu registers.
2866  */
irq_set_irqchip_state(unsigned int irq,enum irqchip_irq_state which,bool val)2867 int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
2868 			  bool val)
2869 {
2870 	struct irq_desc *desc;
2871 	struct irq_data *data;
2872 	struct irq_chip *chip;
2873 	unsigned long flags;
2874 	int err = -EINVAL;
2875 
2876 	desc = irq_get_desc_buslock(irq, &flags, 0);
2877 	if (!desc)
2878 		return err;
2879 
2880 	data = irq_desc_get_irq_data(desc);
2881 
2882 	do {
2883 		chip = irq_data_get_irq_chip(data);
2884 		if (WARN_ON_ONCE(!chip)) {
2885 			err = -ENODEV;
2886 			goto out_unlock;
2887 		}
2888 		if (chip->irq_set_irqchip_state)
2889 			break;
2890 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
2891 		data = data->parent_data;
2892 #else
2893 		data = NULL;
2894 #endif
2895 	} while (data);
2896 
2897 	if (data)
2898 		err = chip->irq_set_irqchip_state(data, which, val);
2899 
2900 out_unlock:
2901 	irq_put_desc_busunlock(desc, flags);
2902 	return err;
2903 }
2904 EXPORT_SYMBOL_GPL(irq_set_irqchip_state);
2905 
2906 /**
2907  * irq_has_action - Check whether an interrupt is requested
2908  * @irq:	The linux irq number
2909  *
2910  * Returns: A snapshot of the current state
2911  */
irq_has_action(unsigned int irq)2912 bool irq_has_action(unsigned int irq)
2913 {
2914 	bool res;
2915 
2916 	rcu_read_lock();
2917 	res = irq_desc_has_action(irq_to_desc(irq));
2918 	rcu_read_unlock();
2919 	return res;
2920 }
2921 EXPORT_SYMBOL_GPL(irq_has_action);
2922 
2923 /**
2924  * irq_check_status_bit - Check whether bits in the irq descriptor status are set
2925  * @irq:	The linux irq number
2926  * @bitmask:	The bitmask to evaluate
2927  *
2928  * Returns: True if one of the bits in @bitmask is set
2929  */
irq_check_status_bit(unsigned int irq,unsigned int bitmask)2930 bool irq_check_status_bit(unsigned int irq, unsigned int bitmask)
2931 {
2932 	struct irq_desc *desc;
2933 	bool res = false;
2934 
2935 	rcu_read_lock();
2936 	desc = irq_to_desc(irq);
2937 	if (desc)
2938 		res = !!(desc->status_use_accessors & bitmask);
2939 	rcu_read_unlock();
2940 	return res;
2941 }
2942 EXPORT_SYMBOL_GPL(irq_check_status_bit);
2943