manage.c 54.9 KB
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/*
 * linux/kernel/irq/manage.c
 *
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 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
 * Copyright (C) 2005-2006 Thomas Gleixner
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 *
 * This file contains driver APIs to the irq subsystem.
 */

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#define pr_fmt(fmt) "genirq: " fmt

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#include <linux/irq.h>
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#include <linux/kthread.h>
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#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/sched/rt.h>
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#include <linux/sched/task.h>
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#include <uapi/linux/sched/types.h>
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#include <linux/task_work.h>
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#include "internals.h"

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#ifdef CONFIG_IRQ_FORCED_THREADING
__read_mostly bool force_irqthreads;

static int __init setup_forced_irqthreads(char *arg)
{
	force_irqthreads = true;
	return 0;
}
early_param("threadirqs", setup_forced_irqthreads);
#endif

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static void __synchronize_hardirq(struct irq_desc *desc)
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{
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	bool inprogress;
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	do {
		unsigned long flags;

		/*
		 * Wait until we're out of the critical section.  This might
		 * give the wrong answer due to the lack of memory barriers.
		 */
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		while (irqd_irq_inprogress(&desc->irq_data))
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			cpu_relax();

		/* Ok, that indicated we're done: double-check carefully. */
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		raw_spin_lock_irqsave(&desc->lock, flags);
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		inprogress = irqd_irq_inprogress(&desc->irq_data);
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		raw_spin_unlock_irqrestore(&desc->lock, flags);
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		/* Oops, that failed? */
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	} while (inprogress);
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}

/**
 *	synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
 *	@irq: interrupt number to wait for
 *
 *	This function waits for any pending hard IRQ handlers for this
 *	interrupt to complete before returning. If you use this
 *	function while holding a resource the IRQ handler may need you
 *	will deadlock. It does not take associated threaded handlers
 *	into account.
 *
 *	Do not use this for shutdown scenarios where you must be sure
 *	that all parts (hardirq and threaded handler) have completed.
 *
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 *	Returns: false if a threaded handler is active.
 *
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 *	This function may be called - with care - from IRQ context.
 */
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bool synchronize_hardirq(unsigned int irq)
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{
	struct irq_desc *desc = irq_to_desc(irq);
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	if (desc) {
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		__synchronize_hardirq(desc);
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		return !atomic_read(&desc->threads_active);
	}

	return true;
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}
EXPORT_SYMBOL(synchronize_hardirq);

/**
 *	synchronize_irq - wait for pending IRQ handlers (on other CPUs)
 *	@irq: interrupt number to wait for
 *
 *	This function waits for any pending IRQ handlers for this interrupt
 *	to complete before returning. If you use this function while
 *	holding a resource the IRQ handler may need you will deadlock.
 *
 *	This function may be called - with care - from IRQ context.
 */
void synchronize_irq(unsigned int irq)
{
	struct irq_desc *desc = irq_to_desc(irq);

	if (desc) {
		__synchronize_hardirq(desc);
		/*
		 * We made sure that no hardirq handler is
		 * running. Now verify that no threaded handlers are
		 * active.
		 */
		wait_event(desc->wait_for_threads,
			   !atomic_read(&desc->threads_active));
	}
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}
EXPORT_SYMBOL(synchronize_irq);

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#ifdef CONFIG_SMP
cpumask_var_t irq_default_affinity;

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static bool __irq_can_set_affinity(struct irq_desc *desc)
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{
	if (!desc || !irqd_can_balance(&desc->irq_data) ||
	    !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
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		return false;
	return true;
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}

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/**
 *	irq_can_set_affinity - Check if the affinity of a given irq can be set
 *	@irq:		Interrupt to check
 *
 */
int irq_can_set_affinity(unsigned int irq)
{
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	return __irq_can_set_affinity(irq_to_desc(irq));
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}

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/**
 * irq_can_set_affinity_usr - Check if affinity of a irq can be set from user space
 * @irq:	Interrupt to check
 *
 * Like irq_can_set_affinity() above, but additionally checks for the
 * AFFINITY_MANAGED flag.
 */
bool irq_can_set_affinity_usr(unsigned int irq)
{
	struct irq_desc *desc = irq_to_desc(irq);

	return __irq_can_set_affinity(desc) &&
		!irqd_affinity_is_managed(&desc->irq_data);
}

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/**
 *	irq_set_thread_affinity - Notify irq threads to adjust affinity
 *	@desc:		irq descriptor which has affitnity changed
 *
 *	We just set IRQTF_AFFINITY and delegate the affinity setting
 *	to the interrupt thread itself. We can not call
 *	set_cpus_allowed_ptr() here as we hold desc->lock and this
 *	code can be called from hard interrupt context.
 */
void irq_set_thread_affinity(struct irq_desc *desc)
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{
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	struct irqaction *action;
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	for_each_action_of_desc(desc, action)
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		if (action->thread)
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			set_bit(IRQTF_AFFINITY, &action->thread_flags);
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}

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#ifdef CONFIG_GENERIC_PENDING_IRQ
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static inline bool irq_can_move_pcntxt(struct irq_data *data)
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{
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	return irqd_can_move_in_process_context(data);
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}
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static inline bool irq_move_pending(struct irq_data *data)
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{
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	return irqd_is_setaffinity_pending(data);
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}
static inline void
irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
{
	cpumask_copy(desc->pending_mask, mask);
}
static inline void
irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
{
	cpumask_copy(mask, desc->pending_mask);
}
#else
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static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
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static inline bool irq_move_pending(struct irq_data *data) { return false; }
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static inline void
irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
static inline void
irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
#endif

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int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
			bool force)
{
	struct irq_desc *desc = irq_data_to_desc(data);
	struct irq_chip *chip = irq_data_get_irq_chip(data);
	int ret;

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	ret = chip->irq_set_affinity(data, mask, force);
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	switch (ret) {
	case IRQ_SET_MASK_OK:
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	case IRQ_SET_MASK_OK_DONE:
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		cpumask_copy(desc->irq_common_data.affinity, mask);
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	case IRQ_SET_MASK_OK_NOCOPY:
		irq_set_thread_affinity(desc);
		ret = 0;
	}

	return ret;
}

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int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
			    bool force)
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{
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	struct irq_chip *chip = irq_data_get_irq_chip(data);
	struct irq_desc *desc = irq_data_to_desc(data);
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	int ret = 0;
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	if (!chip || !chip->irq_set_affinity)
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		return -EINVAL;

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	if (irq_can_move_pcntxt(data)) {
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		ret = irq_do_set_affinity(data, mask, force);
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	} else {
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		irqd_set_move_pending(data);
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		irq_copy_pending(desc, mask);
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	}
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	if (desc->affinity_notify) {
		kref_get(&desc->affinity_notify->kref);
		schedule_work(&desc->affinity_notify->work);
	}
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	irqd_set(data, IRQD_AFFINITY_SET);

	return ret;
}

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int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
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{
	struct irq_desc *desc = irq_to_desc(irq);
	unsigned long flags;
	int ret;

	if (!desc)
		return -EINVAL;

	raw_spin_lock_irqsave(&desc->lock, flags);
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	ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
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	raw_spin_unlock_irqrestore(&desc->lock, flags);
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	return ret;
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}

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int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
{
	unsigned long flags;
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	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
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	if (!desc)
		return -EINVAL;
	desc->affinity_hint = m;
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	irq_put_desc_unlock(desc, flags);
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	/* set the initial affinity to prevent every interrupt being on CPU0 */
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	if (m)
		__irq_set_affinity(irq, m, false);
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	return 0;
}
EXPORT_SYMBOL_GPL(irq_set_affinity_hint);

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static void irq_affinity_notify(struct work_struct *work)
{
	struct irq_affinity_notify *notify =
		container_of(work, struct irq_affinity_notify, work);
	struct irq_desc *desc = irq_to_desc(notify->irq);
	cpumask_var_t cpumask;
	unsigned long flags;

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	if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
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		goto out;

	raw_spin_lock_irqsave(&desc->lock, flags);
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	if (irq_move_pending(&desc->irq_data))
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		irq_get_pending(cpumask, desc);
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	else
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		cpumask_copy(cpumask, desc->irq_common_data.affinity);
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	raw_spin_unlock_irqrestore(&desc->lock, flags);

	notify->notify(notify, cpumask);

	free_cpumask_var(cpumask);
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	kref_put(&notify->kref, notify->release);
}

/**
 *	irq_set_affinity_notifier - control notification of IRQ affinity changes
 *	@irq:		Interrupt for which to enable/disable notification
 *	@notify:	Context for notification, or %NULL to disable
 *			notification.  Function pointers must be initialised;
 *			the other fields will be initialised by this function.
 *
 *	Must be called in process context.  Notification may only be enabled
 *	after the IRQ is allocated and must be disabled before the IRQ is
 *	freed using free_irq().
 */
int
irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
{
	struct irq_desc *desc = irq_to_desc(irq);
	struct irq_affinity_notify *old_notify;
	unsigned long flags;

	/* The release function is promised process context */
	might_sleep();

	if (!desc)
		return -EINVAL;

	/* Complete initialisation of *notify */
	if (notify) {
		notify->irq = irq;
		kref_init(&notify->kref);
		INIT_WORK(&notify->work, irq_affinity_notify);
	}

	raw_spin_lock_irqsave(&desc->lock, flags);
	old_notify = desc->affinity_notify;
	desc->affinity_notify = notify;
	raw_spin_unlock_irqrestore(&desc->lock, flags);

	if (old_notify)
		kref_put(&old_notify->kref, old_notify->release);

	return 0;
}
EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);

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#ifndef CONFIG_AUTO_IRQ_AFFINITY
/*
 * Generic version of the affinity autoselector.
 */
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static int irq_setup_affinity(struct irq_desc *desc)
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{
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	struct cpumask *set = irq_default_affinity;
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	int ret, node = irq_desc_get_node(desc);
	static DEFINE_RAW_SPINLOCK(mask_lock);
	static struct cpumask mask;
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	/* Excludes PER_CPU and NO_BALANCE interrupts */
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	if (!__irq_can_set_affinity(desc))
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		return 0;

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	raw_spin_lock(&mask_lock);
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	/*
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	 * Preserve the managed affinity setting and a userspace affinity
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	 * setup, but make sure that one of the targets is online.
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	 */
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	if (irqd_affinity_is_managed(&desc->irq_data) ||
	    irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
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		if (cpumask_intersects(desc->irq_common_data.affinity,
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				       cpu_online_mask))
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			set = desc->irq_common_data.affinity;
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		else
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			irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
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	}
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	cpumask_and(&mask, cpu_online_mask, set);
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	if (node != NUMA_NO_NODE) {
		const struct cpumask *nodemask = cpumask_of_node(node);

		/* make sure at least one of the cpus in nodemask is online */
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		if (cpumask_intersects(&mask, nodemask))
			cpumask_and(&mask, &mask, nodemask);
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	}
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	ret = irq_do_set_affinity(&desc->irq_data, &mask, false);
	raw_spin_unlock(&mask_lock);
	return ret;
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}
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#else
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/* Wrapper for ALPHA specific affinity selector magic */
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int irq_setup_affinity(struct irq_desc *desc)
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{
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	return irq_select_affinity(irq_desc_get_irq(desc));
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}
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#endif

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/*
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 * Called when a bogus affinity is set via /proc/irq
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 */
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int irq_select_affinity_usr(unsigned int irq)
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{
	struct irq_desc *desc = irq_to_desc(irq);
	unsigned long flags;
	int ret;

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	raw_spin_lock_irqsave(&desc->lock, flags);
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	ret = irq_setup_affinity(desc);
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	raw_spin_unlock_irqrestore(&desc->lock, flags);
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	return ret;
}
#else
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static inline int setup_affinity(struct irq_desc *desc)
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{
	return 0;
}
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#endif

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/**
 *	irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
 *	@irq: interrupt number to set affinity
 *	@vcpu_info: vCPU specific data
 *
 *	This function uses the vCPU specific data to set the vCPU
 *	affinity for an irq. The vCPU specific data is passed from
 *	outside, such as KVM. One example code path is as below:
 *	KVM -> IOMMU -> irq_set_vcpu_affinity().
 */
int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
{
	unsigned long flags;
	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
	struct irq_data *data;
	struct irq_chip *chip;
	int ret = -ENOSYS;

	if (!desc)
		return -EINVAL;

	data = irq_desc_get_irq_data(desc);
	chip = irq_data_get_irq_chip(data);
	if (chip && chip->irq_set_vcpu_affinity)
		ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
	irq_put_desc_unlock(desc, flags);

	return ret;
}
EXPORT_SYMBOL_GPL(irq_set_vcpu_affinity);

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void __disable_irq(struct irq_desc *desc)
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{
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	if (!desc->depth++)
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		irq_disable(desc);
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}

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static int __disable_irq_nosync(unsigned int irq)
{
	unsigned long flags;
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	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
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	if (!desc)
		return -EINVAL;
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	__disable_irq(desc);
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	irq_put_desc_busunlock(desc, flags);
	return 0;
}

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/**
 *	disable_irq_nosync - disable an irq without waiting
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line.  Disables and Enables are
 *	nested.
 *	Unlike disable_irq(), this function does not ensure existing
 *	instances of the IRQ handler have completed before returning.
 *
 *	This function may be called from IRQ context.
 */
void disable_irq_nosync(unsigned int irq)
{
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	__disable_irq_nosync(irq);
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}
EXPORT_SYMBOL(disable_irq_nosync);

/**
 *	disable_irq - disable an irq and wait for completion
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line.  Enables and Disables are
 *	nested.
 *	This function waits for any pending IRQ handlers for this interrupt
 *	to complete before returning. If you use this function while
 *	holding a resource the IRQ handler may need you will deadlock.
 *
 *	This function may be called - with care - from IRQ context.
 */
void disable_irq(unsigned int irq)
{
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	if (!__disable_irq_nosync(irq))
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		synchronize_irq(irq);
}
EXPORT_SYMBOL(disable_irq);

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/**
 *	disable_hardirq - disables an irq and waits for hardirq completion
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line.  Enables and Disables are
 *	nested.
 *	This function waits for any pending hard IRQ handlers for this
 *	interrupt to complete before returning. If you use this function while
 *	holding a resource the hard IRQ handler may need you will deadlock.
 *
 *	When used to optimistically disable an interrupt from atomic context
 *	the return value must be checked.
 *
 *	Returns: false if a threaded handler is active.
 *
 *	This function may be called - with care - from IRQ context.
 */
bool disable_hardirq(unsigned int irq)
{
	if (!__disable_irq_nosync(irq))
		return synchronize_hardirq(irq);

	return false;
}
EXPORT_SYMBOL_GPL(disable_hardirq);

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void __enable_irq(struct irq_desc *desc)
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{
	switch (desc->depth) {
	case 0:
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 err_out:
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		WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n",
		     irq_desc_get_irq(desc));
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		break;
	case 1: {
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		if (desc->istate & IRQS_SUSPENDED)
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			goto err_out;
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		/* Prevent probing on this irq: */
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		irq_settings_set_noprobe(desc);
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		/*
		 * Call irq_startup() not irq_enable() here because the
		 * interrupt might be marked NOAUTOEN. So irq_startup()
		 * needs to be invoked when it gets enabled the first
		 * time. If it was already started up, then irq_startup()
		 * will invoke irq_enable() under the hood.
		 */
		irq_startup(desc, true);
		break;
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	}
	default:
		desc->depth--;
	}
}

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/**
 *	enable_irq - enable handling of an irq
 *	@irq: Interrupt to enable
 *
 *	Undoes the effect of one call to disable_irq().  If this
 *	matches the last disable, processing of interrupts on this
 *	IRQ line is re-enabled.
 *
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 *	This function may be called from IRQ context only when
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 *	desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
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 */
void enable_irq(unsigned int irq)
{
	unsigned long flags;
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	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
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	if (!desc)
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		return;
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	if (WARN(!desc->irq_data.chip,
		 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
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		goto out;
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	__enable_irq(desc);
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out:
	irq_put_desc_busunlock(desc, flags);
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}
EXPORT_SYMBOL(enable_irq);

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static int set_irq_wake_real(unsigned int irq, unsigned int on)
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{
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	struct irq_desc *desc = irq_to_desc(irq);
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	int ret = -ENXIO;

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	if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
		return 0;

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	if (desc->irq_data.chip->irq_set_wake)
		ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
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	return ret;
}

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/**
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 *	irq_set_irq_wake - control irq power management wakeup
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 *	@irq:	interrupt to control
 *	@on:	enable/disable power management wakeup
 *
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 *	Enable/disable power management wakeup mode, which is
 *	disabled by default.  Enables and disables must match,
 *	just as they match for non-wakeup mode support.
 *
 *	Wakeup mode lets this IRQ wake the system from sleep
 *	states like "suspend to RAM".
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 */
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int irq_set_irq_wake(unsigned int irq, unsigned int on)
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{
	unsigned long flags;
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	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
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	int ret = 0;
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	if (!desc)
		return -EINVAL;

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	/* wakeup-capable irqs can be shared between drivers that
	 * don't need to have the same sleep mode behaviors.
	 */
	if (on) {
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		if (desc->wake_depth++ == 0) {
			ret = set_irq_wake_real(irq, on);
			if (ret)
				desc->wake_depth = 0;
			else
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				irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
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		}
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	} else {
		if (desc->wake_depth == 0) {
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			WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
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		} else if (--desc->wake_depth == 0) {
			ret = set_irq_wake_real(irq, on);
			if (ret)
				desc->wake_depth = 1;
			else
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				irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
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		}
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	}
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	irq_put_desc_busunlock(desc, flags);
639 640
	return ret;
}
T
Thomas Gleixner 已提交
641
EXPORT_SYMBOL(irq_set_irq_wake);
642

L
Linus Torvalds 已提交
643 644 645 646 647 648 649
/*
 * Internal function that tells the architecture code whether a
 * particular irq has been exclusively allocated or is available
 * for driver use.
 */
int can_request_irq(unsigned int irq, unsigned long irqflags)
{
650
	unsigned long flags;
651
	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
652
	int canrequest = 0;
L
Linus Torvalds 已提交
653

654 655 656
	if (!desc)
		return 0;

657
	if (irq_settings_can_request(desc)) {
658 659 660
		if (!desc->action ||
		    irqflags & desc->action->flags & IRQF_SHARED)
			canrequest = 1;
661 662 663
	}
	irq_put_desc_unlock(desc, flags);
	return canrequest;
L
Linus Torvalds 已提交
664 665
}

666
int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
667
{
668
	struct irq_chip *chip = desc->irq_data.chip;
669
	int ret, unmask = 0;
670

671
	if (!chip || !chip->irq_set_type) {
672 673 674 675
		/*
		 * IRQF_TRIGGER_* but the PIC does not support multiple
		 * flow-types?
		 */
676 677
		pr_debug("No set_type function for IRQ %d (%s)\n",
			 irq_desc_get_irq(desc),
678
			 chip ? (chip->name ? : "unknown") : "unknown");
679 680 681
		return 0;
	}

682
	if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
683
		if (!irqd_irq_masked(&desc->irq_data))
684
			mask_irq(desc);
685
		if (!irqd_irq_disabled(&desc->irq_data))
686 687 688
			unmask = 1;
	}

689 690
	/* Mask all flags except trigger mode */
	flags &= IRQ_TYPE_SENSE_MASK;
691
	ret = chip->irq_set_type(&desc->irq_data, flags);
692

693 694
	switch (ret) {
	case IRQ_SET_MASK_OK:
695
	case IRQ_SET_MASK_OK_DONE:
696 697 698 699 700 701 702 703 704 705 706 707
		irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
		irqd_set(&desc->irq_data, flags);

	case IRQ_SET_MASK_OK_NOCOPY:
		flags = irqd_get_trigger_type(&desc->irq_data);
		irq_settings_set_trigger_mask(desc, flags);
		irqd_clear(&desc->irq_data, IRQD_LEVEL);
		irq_settings_clr_level(desc);
		if (flags & IRQ_TYPE_LEVEL_MASK) {
			irq_settings_set_level(desc);
			irqd_set(&desc->irq_data, IRQD_LEVEL);
		}
708

709
		ret = 0;
710
		break;
711
	default:
712
		pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
713
		       flags, irq_desc_get_irq(desc), chip->irq_set_type);
D
David Brownell 已提交
714
	}
715 716
	if (unmask)
		unmask_irq(desc);
717 718 719
	return ret;
}

720 721 722 723 724 725 726 727 728 729 730 731 732 733
#ifdef CONFIG_HARDIRQS_SW_RESEND
int irq_set_parent(int irq, int parent_irq)
{
	unsigned long flags;
	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);

	if (!desc)
		return -EINVAL;

	desc->parent_irq = parent_irq;

	irq_put_desc_unlock(desc, flags);
	return 0;
}
734
EXPORT_SYMBOL_GPL(irq_set_parent);
735 736
#endif

T
Thomas Gleixner 已提交
737 738 739 740 741 742 743 744 745 746
/*
 * Default primary interrupt handler for threaded interrupts. Is
 * assigned as primary handler when request_threaded_irq is called
 * with handler == NULL. Useful for oneshot interrupts.
 */
static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
{
	return IRQ_WAKE_THREAD;
}

747 748 749 750 751 752 753 754 755 756
/*
 * Primary handler for nested threaded interrupts. Should never be
 * called.
 */
static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
{
	WARN(1, "Primary handler called for nested irq %d\n", irq);
	return IRQ_NONE;
}

757 758 759 760 761 762
static irqreturn_t irq_forced_secondary_handler(int irq, void *dev_id)
{
	WARN(1, "Secondary action handler called for irq %d\n", irq);
	return IRQ_NONE;
}

763 764
static int irq_wait_for_interrupt(struct irqaction *action)
{
765 766
	set_current_state(TASK_INTERRUPTIBLE);

767
	while (!kthread_should_stop()) {
768 769 770

		if (test_and_clear_bit(IRQTF_RUNTHREAD,
				       &action->thread_flags)) {
771 772
			__set_current_state(TASK_RUNNING);
			return 0;
773 774
		}
		schedule();
775
		set_current_state(TASK_INTERRUPTIBLE);
776
	}
777
	__set_current_state(TASK_RUNNING);
778 779 780
	return -1;
}

T
Thomas Gleixner 已提交
781 782 783 784 785
/*
 * Oneshot interrupts keep the irq line masked until the threaded
 * handler finished. unmask if the interrupt has not been disabled and
 * is marked MASKED.
 */
786
static void irq_finalize_oneshot(struct irq_desc *desc,
787
				 struct irqaction *action)
T
Thomas Gleixner 已提交
788
{
789 790
	if (!(desc->istate & IRQS_ONESHOT) ||
	    action->handler == irq_forced_secondary_handler)
791
		return;
792
again:
793
	chip_bus_lock(desc);
794
	raw_spin_lock_irq(&desc->lock);
795 796 797 798 799 800 801 802

	/*
	 * Implausible though it may be we need to protect us against
	 * the following scenario:
	 *
	 * The thread is faster done than the hard interrupt handler
	 * on the other CPU. If we unmask the irq line then the
	 * interrupt can come in again and masks the line, leaves due
803
	 * to IRQS_INPROGRESS and the irq line is masked forever.
804 805 806 807 808
	 *
	 * This also serializes the state of shared oneshot handlers
	 * versus "desc->threads_onehsot |= action->thread_mask;" in
	 * irq_wake_thread(). See the comment there which explains the
	 * serialization.
809
	 */
810
	if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
811
		raw_spin_unlock_irq(&desc->lock);
812
		chip_bus_sync_unlock(desc);
813 814 815 816
		cpu_relax();
		goto again;
	}

817 818 819 820 821
	/*
	 * Now check again, whether the thread should run. Otherwise
	 * we would clear the threads_oneshot bit of this thread which
	 * was just set.
	 */
822
	if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
823 824 825 826
		goto out_unlock;

	desc->threads_oneshot &= ~action->thread_mask;

827 828
	if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
	    irqd_irq_masked(&desc->irq_data))
829
		unmask_threaded_irq(desc);
830

831
out_unlock:
832
	raw_spin_unlock_irq(&desc->lock);
833
	chip_bus_sync_unlock(desc);
T
Thomas Gleixner 已提交
834 835
}

836
#ifdef CONFIG_SMP
837
/*
838
 * Check whether we need to change the affinity of the interrupt thread.
839 840 841 842 843
 */
static void
irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
{
	cpumask_var_t mask;
844
	bool valid = true;
845 846 847 848 849 850 851 852 853 854 855 856 857

	if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
		return;

	/*
	 * In case we are out of memory we set IRQTF_AFFINITY again and
	 * try again next time
	 */
	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
		set_bit(IRQTF_AFFINITY, &action->thread_flags);
		return;
	}

858
	raw_spin_lock_irq(&desc->lock);
859 860 861 862
	/*
	 * This code is triggered unconditionally. Check the affinity
	 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
	 */
863
	if (cpumask_available(desc->irq_common_data.affinity))
864
		cpumask_copy(mask, desc->irq_common_data.affinity);
865 866
	else
		valid = false;
867
	raw_spin_unlock_irq(&desc->lock);
868

869 870
	if (valid)
		set_cpus_allowed_ptr(current, mask);
871 872
	free_cpumask_var(mask);
}
873 874 875 876
#else
static inline void
irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
#endif
877

878 879 880 881 882 883
/*
 * Interrupts which are not explicitely requested as threaded
 * interrupts rely on the implicit bh/preempt disable of the hard irq
 * context. So we need to disable bh here to avoid deadlocks and other
 * side effects.
 */
884
static irqreturn_t
885 886
irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
{
887 888
	irqreturn_t ret;

889
	local_bh_disable();
890
	ret = action->thread_fn(action->irq, action->dev_id);
891
	irq_finalize_oneshot(desc, action);
892
	local_bh_enable();
893
	return ret;
894 895 896
}

/*
897
 * Interrupts explicitly requested as threaded interrupts want to be
898 899 900
 * preemtible - many of them need to sleep and wait for slow busses to
 * complete.
 */
901 902
static irqreturn_t irq_thread_fn(struct irq_desc *desc,
		struct irqaction *action)
903
{
904 905 906
	irqreturn_t ret;

	ret = action->thread_fn(action->irq, action->dev_id);
907
	irq_finalize_oneshot(desc, action);
908
	return ret;
909 910
}

911 912
static void wake_threads_waitq(struct irq_desc *desc)
{
913
	if (atomic_dec_and_test(&desc->threads_active))
914 915 916
		wake_up(&desc->wait_for_threads);
}

917
static void irq_thread_dtor(struct callback_head *unused)
918 919 920 921 922 923 924 925 926 927
{
	struct task_struct *tsk = current;
	struct irq_desc *desc;
	struct irqaction *action;

	if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
		return;

	action = kthread_data(tsk);

928
	pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
A
Alan Cox 已提交
929
	       tsk->comm, tsk->pid, action->irq);
930 931 932 933 934 935 936 937 938 939 940 941 942 943


	desc = irq_to_desc(action->irq);
	/*
	 * If IRQTF_RUNTHREAD is set, we need to decrement
	 * desc->threads_active and wake possible waiters.
	 */
	if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
		wake_threads_waitq(desc);

	/* Prevent a stale desc->threads_oneshot */
	irq_finalize_oneshot(desc, action);
}

944 945 946 947 948 949 950 951 952 953 954 955
static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action)
{
	struct irqaction *secondary = action->secondary;

	if (WARN_ON_ONCE(!secondary))
		return;

	raw_spin_lock_irq(&desc->lock);
	__irq_wake_thread(desc, secondary);
	raw_spin_unlock_irq(&desc->lock);
}

956 957 958 959 960
/*
 * Interrupt handler thread
 */
static int irq_thread(void *data)
{
961
	struct callback_head on_exit_work;
962 963
	struct irqaction *action = data;
	struct irq_desc *desc = irq_to_desc(action->irq);
964 965
	irqreturn_t (*handler_fn)(struct irq_desc *desc,
			struct irqaction *action);
966

967
	if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
968 969 970 971 972
					&action->thread_flags))
		handler_fn = irq_forced_thread_fn;
	else
		handler_fn = irq_thread_fn;

A
Al Viro 已提交
973
	init_task_work(&on_exit_work, irq_thread_dtor);
974
	task_work_add(current, &on_exit_work, false);
975

976 977
	irq_thread_check_affinity(desc, action);

978
	while (!irq_wait_for_interrupt(action)) {
979
		irqreturn_t action_ret;
980

981 982
		irq_thread_check_affinity(desc, action);

983
		action_ret = handler_fn(desc, action);
984 985
		if (action_ret == IRQ_HANDLED)
			atomic_inc(&desc->threads_handled);
986 987
		if (action_ret == IRQ_WAKE_THREAD)
			irq_wake_secondary(desc, action);
988

989
		wake_threads_waitq(desc);
990 991
	}

992 993 994 995
	/*
	 * This is the regular exit path. __free_irq() is stopping the
	 * thread via kthread_stop() after calling
	 * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
996 997 998 999
	 * oneshot mask bit can be set. We cannot verify that as we
	 * cannot touch the oneshot mask at this point anymore as
	 * __setup_irq() might have given out currents thread_mask
	 * again.
1000
	 */
1001
	task_work_cancel(current, irq_thread_dtor);
1002 1003 1004
	return 0;
}

1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020
/**
 *	irq_wake_thread - wake the irq thread for the action identified by dev_id
 *	@irq:		Interrupt line
 *	@dev_id:	Device identity for which the thread should be woken
 *
 */
void irq_wake_thread(unsigned int irq, void *dev_id)
{
	struct irq_desc *desc = irq_to_desc(irq);
	struct irqaction *action;
	unsigned long flags;

	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
		return;

	raw_spin_lock_irqsave(&desc->lock, flags);
1021
	for_each_action_of_desc(desc, action) {
1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
		if (action->dev_id == dev_id) {
			if (action->thread)
				__irq_wake_thread(desc, action);
			break;
		}
	}
	raw_spin_unlock_irqrestore(&desc->lock, flags);
}
EXPORT_SYMBOL_GPL(irq_wake_thread);

1032
static int irq_setup_forced_threading(struct irqaction *new)
1033 1034
{
	if (!force_irqthreads)
1035
		return 0;
1036
	if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
1037
		return 0;
1038 1039 1040

	new->flags |= IRQF_ONESHOT;

1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055
	/*
	 * Handle the case where we have a real primary handler and a
	 * thread handler. We force thread them as well by creating a
	 * secondary action.
	 */
	if (new->handler != irq_default_primary_handler && new->thread_fn) {
		/* Allocate the secondary action */
		new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
		if (!new->secondary)
			return -ENOMEM;
		new->secondary->handler = irq_forced_secondary_handler;
		new->secondary->thread_fn = new->thread_fn;
		new->secondary->dev_id = new->dev_id;
		new->secondary->irq = new->irq;
		new->secondary->name = new->name;
1056
	}
1057 1058 1059 1060 1061
	/* Deal with the primary handler */
	set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
	new->thread_fn = new->handler;
	new->handler = irq_default_primary_handler;
	return 0;
1062 1063
}

1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
static int irq_request_resources(struct irq_desc *desc)
{
	struct irq_data *d = &desc->irq_data;
	struct irq_chip *c = d->chip;

	return c->irq_request_resources ? c->irq_request_resources(d) : 0;
}

static void irq_release_resources(struct irq_desc *desc)
{
	struct irq_data *d = &desc->irq_data;
	struct irq_chip *c = d->chip;

	if (c->irq_release_resources)
		c->irq_release_resources(d);
}

1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122
static int
setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
{
	struct task_struct *t;
	struct sched_param param = {
		.sched_priority = MAX_USER_RT_PRIO/2,
	};

	if (!secondary) {
		t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
				   new->name);
	} else {
		t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq,
				   new->name);
		param.sched_priority -= 1;
	}

	if (IS_ERR(t))
		return PTR_ERR(t);

	sched_setscheduler_nocheck(t, SCHED_FIFO, &param);

	/*
	 * We keep the reference to the task struct even if
	 * the thread dies to avoid that the interrupt code
	 * references an already freed task_struct.
	 */
	get_task_struct(t);
	new->thread = t;
	/*
	 * Tell the thread to set its affinity. This is
	 * important for shared interrupt handlers as we do
	 * not invoke setup_affinity() for the secondary
	 * handlers as everything is already set up. Even for
	 * interrupts marked with IRQF_NO_BALANCE this is
	 * correct as we want the thread to move to the cpu(s)
	 * on which the requesting code placed the interrupt.
	 */
	set_bit(IRQTF_AFFINITY, &new->thread_flags);
	return 0;
}

L
Linus Torvalds 已提交
1123 1124 1125 1126
/*
 * Internal function to register an irqaction - typically used to
 * allocate special interrupts that are part of the architecture.
 */
1127
static int
I
Ingo Molnar 已提交
1128
__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
L
Linus Torvalds 已提交
1129
{
1130
	struct irqaction *old, **old_ptr;
1131
	unsigned long flags, thread_mask = 0;
1132
	int ret, nested, shared = 0;
L
Linus Torvalds 已提交
1133

1134
	if (!desc)
1135 1136
		return -EINVAL;

1137
	if (desc->irq_data.chip == &no_irq_chip)
L
Linus Torvalds 已提交
1138
		return -ENOSYS;
1139 1140
	if (!try_module_get(desc->owner))
		return -ENODEV;
L
Linus Torvalds 已提交
1141

1142 1143
	new->irq = irq;

1144 1145 1146 1147 1148 1149 1150
	/*
	 * If the trigger type is not specified by the caller,
	 * then use the default for this interrupt.
	 */
	if (!(new->flags & IRQF_TRIGGER_MASK))
		new->flags |= irqd_get_trigger_type(&desc->irq_data);

1151
	/*
1152 1153 1154
	 * Check whether the interrupt nests into another interrupt
	 * thread.
	 */
1155
	nested = irq_settings_is_nested_thread(desc);
1156
	if (nested) {
1157 1158 1159 1160
		if (!new->thread_fn) {
			ret = -EINVAL;
			goto out_mput;
		}
1161 1162 1163 1164 1165 1166
		/*
		 * Replace the primary handler which was provided from
		 * the driver for non nested interrupt handling by the
		 * dummy function which warns when called.
		 */
		new->handler = irq_nested_primary_handler;
1167
	} else {
1168 1169 1170 1171 1172
		if (irq_settings_can_thread(desc)) {
			ret = irq_setup_forced_threading(new);
			if (ret)
				goto out_mput;
		}
1173 1174
	}

1175
	/*
1176 1177 1178
	 * Create a handler thread when a thread function is supplied
	 * and the interrupt does not nest into another interrupt
	 * thread.
1179
	 */
1180
	if (new->thread_fn && !nested) {
1181 1182
		ret = setup_irq_thread(new, irq, false);
		if (ret)
1183
			goto out_mput;
1184 1185 1186 1187
		if (new->secondary) {
			ret = setup_irq_thread(new->secondary, irq, true);
			if (ret)
				goto out_thread;
1188
		}
1189 1190
	}

1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202
	/*
	 * Drivers are often written to work w/o knowledge about the
	 * underlying irq chip implementation, so a request for a
	 * threaded irq without a primary hard irq context handler
	 * requires the ONESHOT flag to be set. Some irq chips like
	 * MSI based interrupts are per se one shot safe. Check the
	 * chip flags, so we can avoid the unmask dance at the end of
	 * the threaded handler for those.
	 */
	if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
		new->flags &= ~IRQF_ONESHOT;

L
Linus Torvalds 已提交
1203 1204 1205
	/*
	 * The following block of code has to be executed atomically
	 */
1206
	raw_spin_lock_irqsave(&desc->lock, flags);
1207 1208
	old_ptr = &desc->action;
	old = *old_ptr;
1209
	if (old) {
1210 1211 1212
		/*
		 * Can't share interrupts unless both agree to and are
		 * the same type (level, edge, polarity). So both flag
1213
		 * fields must have IRQF_SHARED set and the bits which
1214 1215
		 * set the trigger type must match. Also all must
		 * agree on ONESHOT.
1216
		 */
1217 1218
		unsigned int oldtype = irqd_get_trigger_type(&desc->irq_data);

1219
		if (!((old->flags & new->flags) & IRQF_SHARED) ||
1220
		    (oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
1221
		    ((old->flags ^ new->flags) & IRQF_ONESHOT))
1222 1223 1224
			goto mismatch;

		/* All handlers must agree on per-cpuness */
1225 1226
		if ((old->flags & IRQF_PERCPU) !=
		    (new->flags & IRQF_PERCPU))
1227
			goto mismatch;
L
Linus Torvalds 已提交
1228 1229 1230

		/* add new interrupt at end of irq queue */
		do {
1231 1232 1233 1234 1235
			/*
			 * Or all existing action->thread_mask bits,
			 * so we can find the next zero bit for this
			 * new action.
			 */
1236
			thread_mask |= old->thread_mask;
1237 1238
			old_ptr = &old->next;
			old = *old_ptr;
L
Linus Torvalds 已提交
1239 1240 1241 1242
		} while (old);
		shared = 1;
	}

1243
	/*
1244 1245 1246
	 * Setup the thread mask for this irqaction for ONESHOT. For
	 * !ONESHOT irqs the thread mask is 0 so we can avoid a
	 * conditional in irq_wake_thread().
1247
	 */
1248 1249 1250 1251 1252 1253 1254
	if (new->flags & IRQF_ONESHOT) {
		/*
		 * Unlikely to have 32 resp 64 irqs sharing one line,
		 * but who knows.
		 */
		if (thread_mask == ~0UL) {
			ret = -EBUSY;
1255
			goto out_unlock;
1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277
		}
		/*
		 * The thread_mask for the action is or'ed to
		 * desc->thread_active to indicate that the
		 * IRQF_ONESHOT thread handler has been woken, but not
		 * yet finished. The bit is cleared when a thread
		 * completes. When all threads of a shared interrupt
		 * line have completed desc->threads_active becomes
		 * zero and the interrupt line is unmasked. See
		 * handle.c:irq_wake_thread() for further information.
		 *
		 * If no thread is woken by primary (hard irq context)
		 * interrupt handlers, then desc->threads_active is
		 * also checked for zero to unmask the irq line in the
		 * affected hard irq flow handlers
		 * (handle_[fasteoi|level]_irq).
		 *
		 * The new action gets the first zero bit of
		 * thread_mask assigned. See the loop above which or's
		 * all existing action->thread_mask bits.
		 */
		new->thread_mask = 1 << ffz(thread_mask);
1278

1279 1280
	} else if (new->handler == irq_default_primary_handler &&
		   !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295
		/*
		 * The interrupt was requested with handler = NULL, so
		 * we use the default primary handler for it. But it
		 * does not have the oneshot flag set. In combination
		 * with level interrupts this is deadly, because the
		 * default primary handler just wakes the thread, then
		 * the irq lines is reenabled, but the device still
		 * has the level irq asserted. Rinse and repeat....
		 *
		 * While this works for edge type interrupts, we play
		 * it safe and reject unconditionally because we can't
		 * say for sure which type this interrupt really
		 * has. The type flags are unreliable as the
		 * underlying chip implementation can override them.
		 */
1296
		pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1297 1298
		       irq);
		ret = -EINVAL;
1299
		goto out_unlock;
1300 1301
	}

L
Linus Torvalds 已提交
1302
	if (!shared) {
1303 1304 1305 1306
		ret = irq_request_resources(desc);
		if (ret) {
			pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
			       new->name, irq, desc->irq_data.chip->name);
1307
			goto out_unlock;
1308 1309
		}

1310 1311
		init_waitqueue_head(&desc->wait_for_threads);

1312
		/* Setup the type (level, edge polarity) if configured: */
1313
		if (new->flags & IRQF_TRIGGER_MASK) {
1314 1315
			ret = __irq_set_trigger(desc,
						new->flags & IRQF_TRIGGER_MASK);
1316

1317 1318
			if (ret) {
				irq_release_resources(desc);
1319
				goto out_unlock;
1320
			}
1321
		}
T
Thomas Gleixner 已提交
1322

1323
		desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1324 1325
				  IRQS_ONESHOT | IRQS_WAITING);
		irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1326

1327 1328 1329 1330
		if (new->flags & IRQF_PERCPU) {
			irqd_set(&desc->irq_data, IRQD_PER_CPU);
			irq_settings_set_per_cpu(desc);
		}
1331

T
Thomas Gleixner 已提交
1332
		if (new->flags & IRQF_ONESHOT)
1333
			desc->istate |= IRQS_ONESHOT;
T
Thomas Gleixner 已提交
1334

1335
		if (irq_settings_can_autoenable(desc)) {
1336
			irq_startup(desc, true);
1337 1338 1339 1340 1341 1342 1343 1344
		} else {
			/*
			 * Shared interrupts do not go well with disabling
			 * auto enable. The sharing interrupt might request
			 * it while it's still disabled and then wait for
			 * interrupts forever.
			 */
			WARN_ON_ONCE(new->flags & IRQF_SHARED);
1345 1346
			/* Undo nested disables: */
			desc->depth = 1;
1347
		}
1348

1349
		/* Exclude IRQ from balancing if requested */
1350 1351 1352 1353
		if (new->flags & IRQF_NOBALANCING) {
			irq_settings_set_no_balancing(desc);
			irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
		}
1354

1355
		/* Set default affinity mask once everything is setup */
1356
		irq_setup_affinity(desc);
D
David Brownell 已提交
1357

1358 1359
	} else if (new->flags & IRQF_TRIGGER_MASK) {
		unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1360
		unsigned int omsk = irqd_get_trigger_type(&desc->irq_data);
1361 1362 1363

		if (nmsk != omsk)
			/* hope the handler works with current  trigger mode */
1364
			pr_warn("irq %d uses trigger mode %u; requested %u\n",
1365
				irq, omsk, nmsk);
L
Linus Torvalds 已提交
1366
	}
1367

1368
	*old_ptr = new;
1369

1370 1371
	irq_pm_install_action(desc, new);

1372 1373 1374
	/* Reset broken irq detection when installing new handler */
	desc->irq_count = 0;
	desc->irqs_unhandled = 0;
1375 1376 1377 1378 1379

	/*
	 * Check whether we disabled the irq via the spurious handler
	 * before. Reenable it and give it another chance.
	 */
1380 1381
	if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
		desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1382
		__enable_irq(desc);
1383 1384
	}

1385
	raw_spin_unlock_irqrestore(&desc->lock, flags);
L
Linus Torvalds 已提交
1386

1387 1388 1389 1390 1391 1392
	/*
	 * Strictly no need to wake it up, but hung_task complains
	 * when no hard interrupt wakes the thread up.
	 */
	if (new->thread)
		wake_up_process(new->thread);
1393 1394
	if (new->secondary)
		wake_up_process(new->secondary->thread);
1395

1396
	register_irq_proc(irq, desc);
1397
	irq_add_debugfs_entry(irq, desc);
L
Linus Torvalds 已提交
1398 1399 1400
	new->dir = NULL;
	register_handler_proc(irq, new);
	return 0;
1401 1402

mismatch:
1403
	if (!(new->flags & IRQF_PROBE_SHARED)) {
1404
		pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1405 1406
		       irq, new->flags, new->name, old->flags, old->name);
#ifdef CONFIG_DEBUG_SHIRQ
1407
		dump_stack();
1408
#endif
1409
	}
1410 1411
	ret = -EBUSY;

1412
out_unlock:
1413
	raw_spin_unlock_irqrestore(&desc->lock, flags);
1414

1415 1416 1417 1418 1419
out_thread:
	if (new->thread) {
		struct task_struct *t = new->thread;

		new->thread = NULL;
1420
		kthread_stop(t);
1421 1422
		put_task_struct(t);
	}
1423 1424 1425 1426 1427 1428 1429
	if (new->secondary && new->secondary->thread) {
		struct task_struct *t = new->secondary->thread;

		new->secondary->thread = NULL;
		kthread_stop(t);
		put_task_struct(t);
	}
1430 1431
out_mput:
	module_put(desc->owner);
1432
	return ret;
L
Linus Torvalds 已提交
1433 1434
}

1435 1436 1437 1438 1439 1440 1441 1442 1443
/**
 *	setup_irq - setup an interrupt
 *	@irq: Interrupt line to setup
 *	@act: irqaction for the interrupt
 *
 * Used to statically setup interrupts in the early boot process.
 */
int setup_irq(unsigned int irq, struct irqaction *act)
{
1444
	int retval;
1445 1446
	struct irq_desc *desc = irq_to_desc(irq);

1447
	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1448
		return -EINVAL;
1449 1450 1451 1452 1453

	retval = irq_chip_pm_get(&desc->irq_data);
	if (retval < 0)
		return retval;

1454 1455 1456 1457
	chip_bus_lock(desc);
	retval = __setup_irq(irq, desc, act);
	chip_bus_sync_unlock(desc);

1458 1459 1460
	if (retval)
		irq_chip_pm_put(&desc->irq_data);

1461
	return retval;
1462
}
1463
EXPORT_SYMBOL_GPL(setup_irq);
1464

1465
/*
1466 1467
 * Internal function to unregister an irqaction - used to free
 * regular and special interrupts that are part of the architecture.
L
Linus Torvalds 已提交
1468
 */
1469
static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
L
Linus Torvalds 已提交
1470
{
1471
	struct irq_desc *desc = irq_to_desc(irq);
1472
	struct irqaction *action, **action_ptr;
L
Linus Torvalds 已提交
1473 1474
	unsigned long flags;

1475
	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1476 1477

	if (!desc)
1478
		return NULL;
L
Linus Torvalds 已提交
1479

1480
	chip_bus_lock(desc);
1481
	raw_spin_lock_irqsave(&desc->lock, flags);
1482 1483 1484 1485 1486

	/*
	 * There can be multiple actions per IRQ descriptor, find the right
	 * one based on the dev_id:
	 */
1487
	action_ptr = &desc->action;
L
Linus Torvalds 已提交
1488
	for (;;) {
1489
		action = *action_ptr;
L
Linus Torvalds 已提交
1490

1491 1492
		if (!action) {
			WARN(1, "Trying to free already-free IRQ %d\n", irq);
1493
			raw_spin_unlock_irqrestore(&desc->lock, flags);
1494
			chip_bus_sync_unlock(desc);
1495
			return NULL;
1496
		}
L
Linus Torvalds 已提交
1497

1498 1499
		if (action->dev_id == dev_id)
			break;
1500
		action_ptr = &action->next;
1501
	}
1502

1503
	/* Found it - now remove it from the list of entries: */
1504
	*action_ptr = action->next;
1505

1506 1507
	irq_pm_remove_action(desc, action);

1508
	/* If this was the last handler, shut down the IRQ line: */
1509
	if (!desc->action) {
1510
		irq_settings_clr_disable_unlazy(desc);
1511
		irq_shutdown(desc);
1512 1513
		irq_release_resources(desc);
	}
1514

1515 1516 1517 1518 1519 1520
#ifdef CONFIG_SMP
	/* make sure affinity_hint is cleaned up */
	if (WARN_ON_ONCE(desc->affinity_hint))
		desc->affinity_hint = NULL;
#endif

1521
	raw_spin_unlock_irqrestore(&desc->lock, flags);
1522
	chip_bus_sync_unlock(desc);
1523 1524 1525 1526 1527

	unregister_handler_proc(irq, action);

	/* Make sure it's not being used on another CPU: */
	synchronize_irq(irq);
L
Linus Torvalds 已提交
1528

1529
#ifdef CONFIG_DEBUG_SHIRQ
1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
	/*
	 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
	 * event to happen even now it's being freed, so let's make sure that
	 * is so by doing an extra call to the handler ....
	 *
	 * ( We do this after actually deregistering it, to make sure that a
	 *   'real' IRQ doesn't run in * parallel with our fake. )
	 */
	if (action->flags & IRQF_SHARED) {
		local_irq_save(flags);
		action->handler(irq, dev_id);
		local_irq_restore(flags);
L
Linus Torvalds 已提交
1542
	}
1543
#endif
1544 1545

	if (action->thread) {
1546
		kthread_stop(action->thread);
1547
		put_task_struct(action->thread);
1548 1549 1550 1551
		if (action->secondary && action->secondary->thread) {
			kthread_stop(action->secondary->thread);
			put_task_struct(action->secondary->thread);
		}
1552 1553
	}

1554
	irq_chip_pm_put(&desc->irq_data);
1555
	module_put(desc->owner);
1556
	kfree(action->secondary);
1557 1558 1559
	return action;
}

1560 1561 1562 1563 1564 1565 1566 1567 1568
/**
 *	remove_irq - free an interrupt
 *	@irq: Interrupt line to free
 *	@act: irqaction for the interrupt
 *
 * Used to remove interrupts statically setup by the early boot process.
 */
void remove_irq(unsigned int irq, struct irqaction *act)
{
1569 1570 1571
	struct irq_desc *desc = irq_to_desc(irq);

	if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1572
		__free_irq(irq, act->dev_id);
1573
}
1574
EXPORT_SYMBOL_GPL(remove_irq);
1575

1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588
/**
 *	free_irq - free an interrupt allocated with request_irq
 *	@irq: Interrupt line to free
 *	@dev_id: Device identity to free
 *
 *	Remove an interrupt handler. The handler is removed and if the
 *	interrupt line is no longer in use by any driver it is disabled.
 *	On a shared IRQ the caller must ensure the interrupt is disabled
 *	on the card it drives before calling this function. The function
 *	does not return until any executing interrupts for this IRQ
 *	have completed.
 *
 *	This function must not be called from interrupt context.
1589 1590
 *
 *	Returns the devname argument passed to request_irq.
1591
 */
1592
const void *free_irq(unsigned int irq, void *dev_id)
1593
{
T
Thomas Gleixner 已提交
1594
	struct irq_desc *desc = irq_to_desc(irq);
1595 1596
	struct irqaction *action;
	const char *devname;
T
Thomas Gleixner 已提交
1597

1598
	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1599
		return NULL;
T
Thomas Gleixner 已提交
1600

1601 1602 1603 1604 1605
#ifdef CONFIG_SMP
	if (WARN_ON(desc->affinity_notify))
		desc->affinity_notify = NULL;
#endif

1606 1607 1608 1609
	action = __free_irq(irq, dev_id);
	devname = action->name;
	kfree(action);
	return devname;
L
Linus Torvalds 已提交
1610 1611 1612 1613
}
EXPORT_SYMBOL(free_irq);

/**
1614
 *	request_threaded_irq - allocate an interrupt line
L
Linus Torvalds 已提交
1615
 *	@irq: Interrupt line to allocate
1616 1617
 *	@handler: Function to be called when the IRQ occurs.
 *		  Primary handler for threaded interrupts
T
Thomas Gleixner 已提交
1618 1619
 *		  If NULL and thread_fn != NULL the default
 *		  primary handler is installed
1620 1621
 *	@thread_fn: Function called from the irq handler thread
 *		    If NULL, no irq thread is created
L
Linus Torvalds 已提交
1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632
 *	@irqflags: Interrupt type flags
 *	@devname: An ascii name for the claiming device
 *	@dev_id: A cookie passed back to the handler function
 *
 *	This call allocates interrupt resources and enables the
 *	interrupt line and IRQ handling. From the point this
 *	call is made your handler function may be invoked. Since
 *	your handler function must clear any interrupt the board
 *	raises, you must take care both to initialise your hardware
 *	and to set up the interrupt handler in the right order.
 *
1633
 *	If you want to set up a threaded irq handler for your device
J
Javi Merino 已提交
1634
 *	then you need to supply @handler and @thread_fn. @handler is
1635 1636 1637
 *	still called in hard interrupt context and has to check
 *	whether the interrupt originates from the device. If yes it
 *	needs to disable the interrupt on the device and return
1638
 *	IRQ_WAKE_THREAD which will wake up the handler thread and run
1639 1640 1641
 *	@thread_fn. This split handler design is necessary to support
 *	shared interrupts.
 *
L
Linus Torvalds 已提交
1642 1643 1644 1645 1646 1647 1648 1649 1650
 *	Dev_id must be globally unique. Normally the address of the
 *	device data structure is used as the cookie. Since the handler
 *	receives this value it makes sense to use it.
 *
 *	If your interrupt is shared you must pass a non NULL dev_id
 *	as this is required when freeing the interrupt.
 *
 *	Flags:
 *
1651
 *	IRQF_SHARED		Interrupt is shared
D
David Brownell 已提交
1652
 *	IRQF_TRIGGER_*		Specify active edge(s) or level
L
Linus Torvalds 已提交
1653 1654
 *
 */
1655 1656 1657
int request_threaded_irq(unsigned int irq, irq_handler_t handler,
			 irq_handler_t thread_fn, unsigned long irqflags,
			 const char *devname, void *dev_id)
L
Linus Torvalds 已提交
1658
{
1659
	struct irqaction *action;
1660
	struct irq_desc *desc;
1661
	int retval;
L
Linus Torvalds 已提交
1662

1663 1664 1665
	if (irq == IRQ_NOTCONNECTED)
		return -ENOTCONN;

L
Linus Torvalds 已提交
1666 1667 1668 1669 1670
	/*
	 * Sanity-check: shared interrupts must pass in a real dev-ID,
	 * otherwise we'll have trouble later trying to figure out
	 * which interrupt is which (messes up the interrupt freeing
	 * logic etc).
1671 1672 1673
	 *
	 * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
	 * it cannot be set along with IRQF_NO_SUSPEND.
L
Linus Torvalds 已提交
1674
	 */
1675 1676 1677
	if (((irqflags & IRQF_SHARED) && !dev_id) ||
	    (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
	    ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
L
Linus Torvalds 已提交
1678
		return -EINVAL;
1679

1680
	desc = irq_to_desc(irq);
1681
	if (!desc)
L
Linus Torvalds 已提交
1682
		return -EINVAL;
1683

1684 1685
	if (!irq_settings_can_request(desc) ||
	    WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1686
		return -EINVAL;
T
Thomas Gleixner 已提交
1687 1688 1689 1690 1691 1692

	if (!handler) {
		if (!thread_fn)
			return -EINVAL;
		handler = irq_default_primary_handler;
	}
L
Linus Torvalds 已提交
1693

1694
	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
L
Linus Torvalds 已提交
1695 1696 1697 1698
	if (!action)
		return -ENOMEM;

	action->handler = handler;
1699
	action->thread_fn = thread_fn;
L
Linus Torvalds 已提交
1700 1701 1702 1703
	action->flags = irqflags;
	action->name = devname;
	action->dev_id = dev_id;

1704
	retval = irq_chip_pm_get(&desc->irq_data);
1705 1706
	if (retval < 0) {
		kfree(action);
1707
		return retval;
1708
	}
1709

1710
	chip_bus_lock(desc);
1711
	retval = __setup_irq(irq, desc, action);
1712
	chip_bus_sync_unlock(desc);
T
Thomas Gleixner 已提交
1713

1714
	if (retval) {
1715
		irq_chip_pm_put(&desc->irq_data);
1716
		kfree(action->secondary);
1717
		kfree(action);
1718
	}
1719

1720
#ifdef CONFIG_DEBUG_SHIRQ_FIXME
1721
	if (!retval && (irqflags & IRQF_SHARED)) {
D
David Woodhouse 已提交
1722 1723 1724
		/*
		 * It's a shared IRQ -- the driver ought to be prepared for it
		 * to happen immediately, so let's make sure....
1725 1726
		 * We disable the irq to make sure that a 'real' IRQ doesn't
		 * run in parallel with our fake.
D
David Woodhouse 已提交
1727
		 */
1728
		unsigned long flags;
D
David Woodhouse 已提交
1729

1730
		disable_irq(irq);
1731
		local_irq_save(flags);
1732

1733
		handler(irq, dev_id);
1734

1735
		local_irq_restore(flags);
1736
		enable_irq(irq);
D
David Woodhouse 已提交
1737 1738
	}
#endif
L
Linus Torvalds 已提交
1739 1740
	return retval;
}
1741
EXPORT_SYMBOL(request_threaded_irq);
1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762

/**
 *	request_any_context_irq - allocate an interrupt line
 *	@irq: Interrupt line to allocate
 *	@handler: Function to be called when the IRQ occurs.
 *		  Threaded handler for threaded interrupts.
 *	@flags: Interrupt type flags
 *	@name: An ascii name for the claiming device
 *	@dev_id: A cookie passed back to the handler function
 *
 *	This call allocates interrupt resources and enables the
 *	interrupt line and IRQ handling. It selects either a
 *	hardirq or threaded handling method depending on the
 *	context.
 *
 *	On failure, it returns a negative value. On success,
 *	it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
 */
int request_any_context_irq(unsigned int irq, irq_handler_t handler,
			    unsigned long flags, const char *name, void *dev_id)
{
1763
	struct irq_desc *desc;
1764 1765
	int ret;

1766 1767 1768 1769
	if (irq == IRQ_NOTCONNECTED)
		return -ENOTCONN;

	desc = irq_to_desc(irq);
1770 1771 1772
	if (!desc)
		return -EINVAL;

1773
	if (irq_settings_is_nested_thread(desc)) {
1774 1775 1776 1777 1778 1779 1780 1781 1782
		ret = request_threaded_irq(irq, NULL, handler,
					   flags, name, dev_id);
		return !ret ? IRQC_IS_NESTED : ret;
	}

	ret = request_irq(irq, handler, flags, name, dev_id);
	return !ret ? IRQC_IS_HARDIRQ : ret;
}
EXPORT_SYMBOL_GPL(request_any_context_irq);
1783

1784
void enable_percpu_irq(unsigned int irq, unsigned int type)
1785 1786 1787 1788 1789 1790 1791 1792
{
	unsigned int cpu = smp_processor_id();
	unsigned long flags;
	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);

	if (!desc)
		return;

1793 1794 1795 1796
	/*
	 * If the trigger type is not specified by the caller, then
	 * use the default for this interrupt.
	 */
1797
	type &= IRQ_TYPE_SENSE_MASK;
1798 1799 1800
	if (type == IRQ_TYPE_NONE)
		type = irqd_get_trigger_type(&desc->irq_data);

1801 1802 1803
	if (type != IRQ_TYPE_NONE) {
		int ret;

1804
		ret = __irq_set_trigger(desc, type);
1805 1806

		if (ret) {
1807
			WARN(1, "failed to set type for IRQ%d\n", irq);
1808 1809 1810 1811
			goto out;
		}
	}

1812
	irq_percpu_enable(desc, cpu);
1813
out:
1814 1815
	irq_put_desc_unlock(desc, flags);
}
1816
EXPORT_SYMBOL_GPL(enable_percpu_irq);
1817

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/**
 * irq_percpu_is_enabled - Check whether the per cpu irq is enabled
 * @irq:	Linux irq number to check for
 *
 * Must be called from a non migratable context. Returns the enable
 * state of a per cpu interrupt on the current cpu.
 */
bool irq_percpu_is_enabled(unsigned int irq)
{
	unsigned int cpu = smp_processor_id();
	struct irq_desc *desc;
	unsigned long flags;
	bool is_enabled;

	desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
	if (!desc)
		return false;

	is_enabled = cpumask_test_cpu(cpu, desc->percpu_enabled);
	irq_put_desc_unlock(desc, flags);

	return is_enabled;
}
EXPORT_SYMBOL_GPL(irq_percpu_is_enabled);

1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854
void disable_percpu_irq(unsigned int irq)
{
	unsigned int cpu = smp_processor_id();
	unsigned long flags;
	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);

	if (!desc)
		return;

	irq_percpu_disable(desc, cpu);
	irq_put_desc_unlock(desc, flags);
}
1855
EXPORT_SYMBOL_GPL(disable_percpu_irq);
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/*
 * Internal function to unregister a percpu irqaction.
 */
static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
{
	struct irq_desc *desc = irq_to_desc(irq);
	struct irqaction *action;
	unsigned long flags;

	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);

	if (!desc)
		return NULL;

	raw_spin_lock_irqsave(&desc->lock, flags);

	action = desc->action;
	if (!action || action->percpu_dev_id != dev_id) {
		WARN(1, "Trying to free already-free IRQ %d\n", irq);
		goto bad;
	}

	if (!cpumask_empty(desc->percpu_enabled)) {
		WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
		     irq, cpumask_first(desc->percpu_enabled));
		goto bad;
	}

	/* Found it - now remove it from the list of entries: */
	desc->action = NULL;

	raw_spin_unlock_irqrestore(&desc->lock, flags);

	unregister_handler_proc(irq, action);

1892
	irq_chip_pm_put(&desc->irq_data);
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	module_put(desc->owner);
	return action;

bad:
	raw_spin_unlock_irqrestore(&desc->lock, flags);
	return NULL;
}

/**
 *	remove_percpu_irq - free a per-cpu interrupt
 *	@irq: Interrupt line to free
 *	@act: irqaction for the interrupt
 *
 * Used to remove interrupts statically setup by the early boot process.
 */
void remove_percpu_irq(unsigned int irq, struct irqaction *act)
{
	struct irq_desc *desc = irq_to_desc(irq);

	if (desc && irq_settings_is_per_cpu_devid(desc))
	    __free_percpu_irq(irq, act->percpu_dev_id);
}

/**
 *	free_percpu_irq - free an interrupt allocated with request_percpu_irq
 *	@irq: Interrupt line to free
 *	@dev_id: Device identity to free
 *
 *	Remove a percpu interrupt handler. The handler is removed, but
 *	the interrupt line is not disabled. This must be done on each
 *	CPU before calling this function. The function does not return
 *	until any executing interrupts for this IRQ have completed.
 *
 *	This function must not be called from interrupt context.
 */
void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
{
	struct irq_desc *desc = irq_to_desc(irq);

	if (!desc || !irq_settings_is_per_cpu_devid(desc))
		return;

	chip_bus_lock(desc);
	kfree(__free_percpu_irq(irq, dev_id));
	chip_bus_sync_unlock(desc);
}
1939
EXPORT_SYMBOL_GPL(free_percpu_irq);
1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954

/**
 *	setup_percpu_irq - setup a per-cpu interrupt
 *	@irq: Interrupt line to setup
 *	@act: irqaction for the interrupt
 *
 * Used to statically setup per-cpu interrupts in the early boot process.
 */
int setup_percpu_irq(unsigned int irq, struct irqaction *act)
{
	struct irq_desc *desc = irq_to_desc(irq);
	int retval;

	if (!desc || !irq_settings_is_per_cpu_devid(desc))
		return -EINVAL;
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	retval = irq_chip_pm_get(&desc->irq_data);
	if (retval < 0)
		return retval;

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	chip_bus_lock(desc);
	retval = __setup_irq(irq, desc, act);
	chip_bus_sync_unlock(desc);

1964 1965 1966
	if (retval)
		irq_chip_pm_put(&desc->irq_data);

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	return retval;
}

/**
 *	request_percpu_irq - allocate a percpu interrupt line
 *	@irq: Interrupt line to allocate
 *	@handler: Function to be called when the IRQ occurs.
 *	@devname: An ascii name for the claiming device
 *	@dev_id: A percpu cookie passed back to the handler function
 *
1977 1978 1979 1980
 *	This call allocates interrupt resources and enables the
 *	interrupt on the local CPU. If the interrupt is supposed to be
 *	enabled on other CPUs, it has to be done on each CPU using
 *	enable_percpu_irq().
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
 *
 *	Dev_id must be globally unique. It is a per-cpu variable, and
 *	the handler gets called with the interrupted CPU's instance of
 *	that variable.
 */
int request_percpu_irq(unsigned int irq, irq_handler_t handler,
		       const char *devname, void __percpu *dev_id)
{
	struct irqaction *action;
	struct irq_desc *desc;
	int retval;

	if (!dev_id)
		return -EINVAL;

	desc = irq_to_desc(irq);
	if (!desc || !irq_settings_can_request(desc) ||
	    !irq_settings_is_per_cpu_devid(desc))
		return -EINVAL;

	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
	if (!action)
		return -ENOMEM;

	action->handler = handler;
2006
	action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
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	action->name = devname;
	action->percpu_dev_id = dev_id;

2010
	retval = irq_chip_pm_get(&desc->irq_data);
2011 2012
	if (retval < 0) {
		kfree(action);
2013
		return retval;
2014
	}
2015

2016 2017 2018 2019
	chip_bus_lock(desc);
	retval = __setup_irq(irq, desc, action);
	chip_bus_sync_unlock(desc);

2020 2021
	if (retval) {
		irq_chip_pm_put(&desc->irq_data);
2022
		kfree(action);
2023
	}
2024 2025 2026

	return retval;
}
2027
EXPORT_SYMBOL_GPL(request_percpu_irq);
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/**
 *	irq_get_irqchip_state - returns the irqchip state of a interrupt.
 *	@irq: Interrupt line that is forwarded to a VM
 *	@which: One of IRQCHIP_STATE_* the caller wants to know about
 *	@state: a pointer to a boolean where the state is to be storeed
 *
 *	This call snapshots the internal irqchip state of an
 *	interrupt, returning into @state the bit corresponding to
 *	stage @which
 *
 *	This function should be called with preemption disabled if the
 *	interrupt controller has per-cpu registers.
 */
int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
			  bool *state)
{
	struct irq_desc *desc;
	struct irq_data *data;
	struct irq_chip *chip;
	unsigned long flags;
	int err = -EINVAL;

	desc = irq_get_desc_buslock(irq, &flags, 0);
	if (!desc)
		return err;

	data = irq_desc_get_irq_data(desc);

	do {
		chip = irq_data_get_irq_chip(data);
		if (chip->irq_get_irqchip_state)
			break;
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
		data = data->parent_data;
#else
		data = NULL;
#endif
	} while (data);

	if (data)
		err = chip->irq_get_irqchip_state(data, which, state);

	irq_put_desc_busunlock(desc, flags);
	return err;
}
2074
EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
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/**
 *	irq_set_irqchip_state - set the state of a forwarded interrupt.
 *	@irq: Interrupt line that is forwarded to a VM
 *	@which: State to be restored (one of IRQCHIP_STATE_*)
 *	@val: Value corresponding to @which
 *
 *	This call sets the internal irqchip state of an interrupt,
 *	depending on the value of @which.
 *
 *	This function should be called with preemption disabled if the
 *	interrupt controller has per-cpu registers.
 */
int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
			  bool val)
{
	struct irq_desc *desc;
	struct irq_data *data;
	struct irq_chip *chip;
	unsigned long flags;
	int err = -EINVAL;

	desc = irq_get_desc_buslock(irq, &flags, 0);
	if (!desc)
		return err;

	data = irq_desc_get_irq_data(desc);

	do {
		chip = irq_data_get_irq_chip(data);
		if (chip->irq_set_irqchip_state)
			break;
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
		data = data->parent_data;
#else
		data = NULL;
#endif
	} while (data);

	if (data)
		err = chip->irq_set_irqchip_state(data, which, val);

	irq_put_desc_busunlock(desc, flags);
	return err;
}
2120
EXPORT_SYMBOL_GPL(irq_set_irqchip_state);