manage.c 52.5 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/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 int __irq_can_set_affinity(struct irq_desc *desc)
{
	if (!desc || !irqd_can_balance(&desc->irq_data) ||
	    !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
		return 0;
	return 1;
}

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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_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 setup_affinity(struct irq_desc *desc, struct cpumask *mask)
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{
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	struct cpumask *set = irq_default_affinity;
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	int node = irq_desc_get_node(desc);
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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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	/*
	 * Preserve an userspace affinity setup, but make sure that
	 * one of the targets is online.
	 */
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	if (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 */
		if (cpumask_intersects(mask, nodemask))
			cpumask_and(mask, mask, nodemask);
	}
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	irq_do_set_affinity(&desc->irq_data, mask, false);
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	return 0;
}
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#else
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/* Wrapper for ALPHA specific affinity selector magic */
static inline int setup_affinity(struct irq_desc *d, struct cpumask *mask)
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{
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	return irq_select_affinity(irq_desc_get_irq(d));
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}
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#endif

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/*
 * Called when affinity is set via /proc/irq
 */
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int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
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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 = setup_affinity(desc, mask);
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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
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setup_affinity(struct irq_desc *desc, struct cpumask *mask)
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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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		irq_enable(desc);
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		check_irq_resend(desc);
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		/* fall-through */
	}
	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);
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	return ret;
}
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EXPORT_SYMBOL(irq_set_irq_wake);
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/*
 * 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)
{
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	unsigned long flags;
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	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
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	int canrequest = 0;
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	if (!desc)
		return 0;

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	if (irq_settings_can_request(desc)) {
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		if (!desc->action ||
		    irqflags & desc->action->flags & IRQF_SHARED)
			canrequest = 1;
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	}
	irq_put_desc_unlock(desc, flags);
	return canrequest;
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}

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int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
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{
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	struct irq_chip *chip = desc->irq_data.chip;
643
	int ret, unmask = 0;
644

645
	if (!chip || !chip->irq_set_type) {
646 647 648 649
		/*
		 * IRQF_TRIGGER_* but the PIC does not support multiple
		 * flow-types?
		 */
650 651
		pr_debug("No set_type function for IRQ %d (%s)\n",
			 irq_desc_get_irq(desc),
652
			 chip ? (chip->name ? : "unknown") : "unknown");
653 654 655
		return 0;
	}

656
	flags &= IRQ_TYPE_SENSE_MASK;
657 658

	if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
659
		if (!irqd_irq_masked(&desc->irq_data))
660
			mask_irq(desc);
661
		if (!irqd_irq_disabled(&desc->irq_data))
662 663 664
			unmask = 1;
	}

665
	/* caller masked out all except trigger mode flags */
666
	ret = chip->irq_set_type(&desc->irq_data, flags);
667

668 669
	switch (ret) {
	case IRQ_SET_MASK_OK:
670
	case IRQ_SET_MASK_OK_DONE:
671 672 673 674 675 676 677 678 679 680 681 682
		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);
		}
683

684
		ret = 0;
685
		break;
686
	default:
687
		pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
688
		       flags, irq_desc_get_irq(desc), chip->irq_set_type);
D
David Brownell 已提交
689
	}
690 691
	if (unmask)
		unmask_irq(desc);
692 693 694
	return ret;
}

695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710
#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;
}
#endif

T
Thomas Gleixner 已提交
711 712 713 714 715 716 717 718 719 720
/*
 * 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;
}

721 722 723 724 725 726 727 728 729 730
/*
 * 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;
}

731 732 733 734 735 736
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;
}

737 738
static int irq_wait_for_interrupt(struct irqaction *action)
{
739 740
	set_current_state(TASK_INTERRUPTIBLE);

741
	while (!kthread_should_stop()) {
742 743 744

		if (test_and_clear_bit(IRQTF_RUNTHREAD,
				       &action->thread_flags)) {
745 746
			__set_current_state(TASK_RUNNING);
			return 0;
747 748
		}
		schedule();
749
		set_current_state(TASK_INTERRUPTIBLE);
750
	}
751
	__set_current_state(TASK_RUNNING);
752 753 754
	return -1;
}

T
Thomas Gleixner 已提交
755 756 757 758 759
/*
 * Oneshot interrupts keep the irq line masked until the threaded
 * handler finished. unmask if the interrupt has not been disabled and
 * is marked MASKED.
 */
760
static void irq_finalize_oneshot(struct irq_desc *desc,
761
				 struct irqaction *action)
T
Thomas Gleixner 已提交
762
{
763 764
	if (!(desc->istate & IRQS_ONESHOT) ||
	    action->handler == irq_forced_secondary_handler)
765
		return;
766
again:
767
	chip_bus_lock(desc);
768
	raw_spin_lock_irq(&desc->lock);
769 770 771 772 773 774 775 776

	/*
	 * 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
777
	 * to IRQS_INPROGRESS and the irq line is masked forever.
778 779 780 781 782
	 *
	 * 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.
783
	 */
784
	if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
785
		raw_spin_unlock_irq(&desc->lock);
786
		chip_bus_sync_unlock(desc);
787 788 789 790
		cpu_relax();
		goto again;
	}

791 792 793 794 795
	/*
	 * Now check again, whether the thread should run. Otherwise
	 * we would clear the threads_oneshot bit of this thread which
	 * was just set.
	 */
796
	if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
797 798 799 800
		goto out_unlock;

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

801 802
	if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
	    irqd_irq_masked(&desc->irq_data))
803
		unmask_threaded_irq(desc);
804

805
out_unlock:
806
	raw_spin_unlock_irq(&desc->lock);
807
	chip_bus_sync_unlock(desc);
T
Thomas Gleixner 已提交
808 809
}

810
#ifdef CONFIG_SMP
811
/*
812
 * Check whether we need to change the affinity of the interrupt thread.
813 814 815 816 817
 */
static void
irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
{
	cpumask_var_t mask;
818
	bool valid = true;
819 820 821 822 823 824 825 826 827 828 829 830 831

	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;
	}

832
	raw_spin_lock_irq(&desc->lock);
833 834 835 836
	/*
	 * This code is triggered unconditionally. Check the affinity
	 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
	 */
837 838
	if (desc->irq_common_data.affinity)
		cpumask_copy(mask, desc->irq_common_data.affinity);
839 840
	else
		valid = false;
841
	raw_spin_unlock_irq(&desc->lock);
842

843 844
	if (valid)
		set_cpus_allowed_ptr(current, mask);
845 846
	free_cpumask_var(mask);
}
847 848 849 850
#else
static inline void
irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
#endif
851

852 853 854 855 856 857
/*
 * 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.
 */
858
static irqreturn_t
859 860
irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
{
861 862
	irqreturn_t ret;

863
	local_bh_disable();
864
	ret = action->thread_fn(action->irq, action->dev_id);
865
	irq_finalize_oneshot(desc, action);
866
	local_bh_enable();
867
	return ret;
868 869 870
}

/*
871
 * Interrupts explicitly requested as threaded interrupts want to be
872 873 874
 * preemtible - many of them need to sleep and wait for slow busses to
 * complete.
 */
875 876
static irqreturn_t irq_thread_fn(struct irq_desc *desc,
		struct irqaction *action)
877
{
878 879 880
	irqreturn_t ret;

	ret = action->thread_fn(action->irq, action->dev_id);
881
	irq_finalize_oneshot(desc, action);
882
	return ret;
883 884
}

885 886
static void wake_threads_waitq(struct irq_desc *desc)
{
887
	if (atomic_dec_and_test(&desc->threads_active))
888 889 890
		wake_up(&desc->wait_for_threads);
}

891
static void irq_thread_dtor(struct callback_head *unused)
892 893 894 895 896 897 898 899 900 901
{
	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);

902
	pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
A
Alan Cox 已提交
903
	       tsk->comm, tsk->pid, action->irq);
904 905 906 907 908 909 910 911 912 913 914 915 916 917


	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);
}

918 919 920 921 922 923 924 925 926 927 928 929
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);
}

930 931 932 933 934
/*
 * Interrupt handler thread
 */
static int irq_thread(void *data)
{
935
	struct callback_head on_exit_work;
936 937
	struct irqaction *action = data;
	struct irq_desc *desc = irq_to_desc(action->irq);
938 939
	irqreturn_t (*handler_fn)(struct irq_desc *desc,
			struct irqaction *action);
940

941
	if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
942 943 944 945 946
					&action->thread_flags))
		handler_fn = irq_forced_thread_fn;
	else
		handler_fn = irq_thread_fn;

A
Al Viro 已提交
947
	init_task_work(&on_exit_work, irq_thread_dtor);
948
	task_work_add(current, &on_exit_work, false);
949

950 951
	irq_thread_check_affinity(desc, action);

952
	while (!irq_wait_for_interrupt(action)) {
953
		irqreturn_t action_ret;
954

955 956
		irq_thread_check_affinity(desc, action);

957
		action_ret = handler_fn(desc, action);
958 959
		if (action_ret == IRQ_HANDLED)
			atomic_inc(&desc->threads_handled);
960 961
		if (action_ret == IRQ_WAKE_THREAD)
			irq_wake_secondary(desc, action);
962

963
		wake_threads_waitq(desc);
964 965
	}

966 967 968 969
	/*
	 * 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
970 971 972 973
	 * 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.
974
	 */
975
	task_work_cancel(current, irq_thread_dtor);
976 977 978
	return 0;
}

979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994
/**
 *	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);
995
	for_each_action_of_desc(desc, action) {
996 997 998 999 1000 1001 1002 1003 1004 1005
		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);

1006
static int irq_setup_forced_threading(struct irqaction *new)
1007 1008
{
	if (!force_irqthreads)
1009
		return 0;
1010
	if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
1011
		return 0;
1012 1013 1014

	new->flags |= IRQF_ONESHOT;

1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029
	/*
	 * 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;
1030
	}
1031 1032 1033 1034 1035
	/* 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;
1036 1037
}

1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054
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);
}

1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096
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
1097 1098 1099 1100
/*
 * Internal function to register an irqaction - typically used to
 * allocate special interrupts that are part of the architecture.
 */
1101
static int
I
Ingo Molnar 已提交
1102
__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
L
Linus Torvalds 已提交
1103
{
1104
	struct irqaction *old, **old_ptr;
1105
	unsigned long flags, thread_mask = 0;
1106 1107
	int ret, nested, shared = 0;
	cpumask_var_t mask;
L
Linus Torvalds 已提交
1108

1109
	if (!desc)
1110 1111
		return -EINVAL;

1112
	if (desc->irq_data.chip == &no_irq_chip)
L
Linus Torvalds 已提交
1113
		return -ENOSYS;
1114 1115
	if (!try_module_get(desc->owner))
		return -ENODEV;
L
Linus Torvalds 已提交
1116

1117 1118
	new->irq = irq;

1119
	/*
1120 1121 1122
	 * Check whether the interrupt nests into another interrupt
	 * thread.
	 */
1123
	nested = irq_settings_is_nested_thread(desc);
1124
	if (nested) {
1125 1126 1127 1128
		if (!new->thread_fn) {
			ret = -EINVAL;
			goto out_mput;
		}
1129 1130 1131 1132 1133 1134
		/*
		 * 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;
1135
	} else {
1136 1137 1138 1139 1140
		if (irq_settings_can_thread(desc)) {
			ret = irq_setup_forced_threading(new);
			if (ret)
				goto out_mput;
		}
1141 1142
	}

1143
	/*
1144 1145 1146
	 * Create a handler thread when a thread function is supplied
	 * and the interrupt does not nest into another interrupt
	 * thread.
1147
	 */
1148
	if (new->thread_fn && !nested) {
1149 1150
		ret = setup_irq_thread(new, irq, false);
		if (ret)
1151
			goto out_mput;
1152 1153 1154 1155
		if (new->secondary) {
			ret = setup_irq_thread(new->secondary, irq, true);
			if (ret)
				goto out_thread;
1156
		}
1157 1158
	}

1159 1160 1161 1162 1163
	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
		ret = -ENOMEM;
		goto out_thread;
	}

1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175
	/*
	 * 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
1176 1177 1178
	/*
	 * The following block of code has to be executed atomically
	 */
1179
	raw_spin_lock_irqsave(&desc->lock, flags);
1180 1181
	old_ptr = &desc->action;
	old = *old_ptr;
1182
	if (old) {
1183 1184 1185
		/*
		 * Can't share interrupts unless both agree to and are
		 * the same type (level, edge, polarity). So both flag
1186
		 * fields must have IRQF_SHARED set and the bits which
1187 1188
		 * set the trigger type must match. Also all must
		 * agree on ONESHOT.
1189
		 */
1190
		if (!((old->flags & new->flags) & IRQF_SHARED) ||
1191
		    ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1192
		    ((old->flags ^ new->flags) & IRQF_ONESHOT))
1193 1194 1195
			goto mismatch;

		/* All handlers must agree on per-cpuness */
1196 1197
		if ((old->flags & IRQF_PERCPU) !=
		    (new->flags & IRQF_PERCPU))
1198
			goto mismatch;
L
Linus Torvalds 已提交
1199 1200 1201

		/* add new interrupt at end of irq queue */
		do {
1202 1203 1204 1205 1206
			/*
			 * Or all existing action->thread_mask bits,
			 * so we can find the next zero bit for this
			 * new action.
			 */
1207
			thread_mask |= old->thread_mask;
1208 1209
			old_ptr = &old->next;
			old = *old_ptr;
L
Linus Torvalds 已提交
1210 1211 1212 1213
		} while (old);
		shared = 1;
	}

1214
	/*
1215 1216 1217
	 * 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().
1218
	 */
1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
	if (new->flags & IRQF_ONESHOT) {
		/*
		 * Unlikely to have 32 resp 64 irqs sharing one line,
		 * but who knows.
		 */
		if (thread_mask == ~0UL) {
			ret = -EBUSY;
			goto out_mask;
		}
		/*
		 * 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);
1249

1250 1251
	} else if (new->handler == irq_default_primary_handler &&
		   !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266
		/*
		 * 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.
		 */
1267
		pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1268 1269 1270
		       irq);
		ret = -EINVAL;
		goto out_mask;
1271 1272
	}

L
Linus Torvalds 已提交
1273
	if (!shared) {
1274 1275 1276 1277 1278 1279 1280
		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);
			goto out_mask;
		}

1281 1282
		init_waitqueue_head(&desc->wait_for_threads);

1283
		/* Setup the type (level, edge polarity) if configured: */
1284
		if (new->flags & IRQF_TRIGGER_MASK) {
1285 1286
			ret = __irq_set_trigger(desc,
						new->flags & IRQF_TRIGGER_MASK);
1287

1288
			if (ret)
1289
				goto out_mask;
1290
		}
T
Thomas Gleixner 已提交
1291

1292
		desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1293 1294
				  IRQS_ONESHOT | IRQS_WAITING);
		irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1295

1296 1297 1298 1299
		if (new->flags & IRQF_PERCPU) {
			irqd_set(&desc->irq_data, IRQD_PER_CPU);
			irq_settings_set_per_cpu(desc);
		}
1300

T
Thomas Gleixner 已提交
1301
		if (new->flags & IRQF_ONESHOT)
1302
			desc->istate |= IRQS_ONESHOT;
T
Thomas Gleixner 已提交
1303

1304
		if (irq_settings_can_autoenable(desc))
1305
			irq_startup(desc, true);
1306
		else
1307 1308
			/* Undo nested disables: */
			desc->depth = 1;
1309

1310
		/* Exclude IRQ from balancing if requested */
1311 1312 1313 1314
		if (new->flags & IRQF_NOBALANCING) {
			irq_settings_set_no_balancing(desc);
			irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
		}
1315

1316
		/* Set default affinity mask once everything is setup */
1317
		setup_affinity(desc, mask);
D
David Brownell 已提交
1318

1319 1320 1321 1322 1323 1324
	} else if (new->flags & IRQF_TRIGGER_MASK) {
		unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
		unsigned int omsk = irq_settings_get_trigger_mask(desc);

		if (nmsk != omsk)
			/* hope the handler works with current  trigger mode */
1325
			pr_warning("irq %d uses trigger mode %u; requested %u\n",
1326
				   irq, nmsk, omsk);
L
Linus Torvalds 已提交
1327
	}
1328

1329
	*old_ptr = new;
1330

1331 1332
	irq_pm_install_action(desc, new);

1333 1334 1335
	/* Reset broken irq detection when installing new handler */
	desc->irq_count = 0;
	desc->irqs_unhandled = 0;
1336 1337 1338 1339 1340

	/*
	 * Check whether we disabled the irq via the spurious handler
	 * before. Reenable it and give it another chance.
	 */
1341 1342
	if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
		desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1343
		__enable_irq(desc);
1344 1345
	}

1346
	raw_spin_unlock_irqrestore(&desc->lock, flags);
L
Linus Torvalds 已提交
1347

1348 1349 1350 1351 1352 1353
	/*
	 * 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);
1354 1355
	if (new->secondary)
		wake_up_process(new->secondary->thread);
1356

1357
	register_irq_proc(irq, desc);
L
Linus Torvalds 已提交
1358 1359
	new->dir = NULL;
	register_handler_proc(irq, new);
1360
	free_cpumask_var(mask);
L
Linus Torvalds 已提交
1361 1362

	return 0;
1363 1364

mismatch:
1365
	if (!(new->flags & IRQF_PROBE_SHARED)) {
1366
		pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1367 1368
		       irq, new->flags, new->name, old->flags, old->name);
#ifdef CONFIG_DEBUG_SHIRQ
1369
		dump_stack();
1370
#endif
1371
	}
1372 1373
	ret = -EBUSY;

1374
out_mask:
1375
	raw_spin_unlock_irqrestore(&desc->lock, flags);
1376 1377
	free_cpumask_var(mask);

1378 1379 1380 1381 1382
out_thread:
	if (new->thread) {
		struct task_struct *t = new->thread;

		new->thread = NULL;
1383
		kthread_stop(t);
1384 1385
		put_task_struct(t);
	}
1386 1387 1388 1389 1390 1391 1392
	if (new->secondary && new->secondary->thread) {
		struct task_struct *t = new->secondary->thread;

		new->secondary->thread = NULL;
		kthread_stop(t);
		put_task_struct(t);
	}
1393 1394
out_mput:
	module_put(desc->owner);
1395
	return ret;
L
Linus Torvalds 已提交
1396 1397
}

1398 1399 1400 1401 1402 1403 1404 1405 1406
/**
 *	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)
{
1407
	int retval;
1408 1409
	struct irq_desc *desc = irq_to_desc(irq);

1410 1411
	if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
		return -EINVAL;
1412 1413 1414 1415 1416
	chip_bus_lock(desc);
	retval = __setup_irq(irq, desc, act);
	chip_bus_sync_unlock(desc);

	return retval;
1417
}
1418
EXPORT_SYMBOL_GPL(setup_irq);
1419

1420
/*
1421 1422
 * 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
1423
 */
1424
static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
L
Linus Torvalds 已提交
1425
{
1426
	struct irq_desc *desc = irq_to_desc(irq);
1427
	struct irqaction *action, **action_ptr;
L
Linus Torvalds 已提交
1428 1429
	unsigned long flags;

1430
	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1431 1432

	if (!desc)
1433
		return NULL;
L
Linus Torvalds 已提交
1434

1435
	chip_bus_lock(desc);
1436
	raw_spin_lock_irqsave(&desc->lock, flags);
1437 1438 1439 1440 1441

	/*
	 * There can be multiple actions per IRQ descriptor, find the right
	 * one based on the dev_id:
	 */
1442
	action_ptr = &desc->action;
L
Linus Torvalds 已提交
1443
	for (;;) {
1444
		action = *action_ptr;
L
Linus Torvalds 已提交
1445

1446 1447
		if (!action) {
			WARN(1, "Trying to free already-free IRQ %d\n", irq);
1448
			raw_spin_unlock_irqrestore(&desc->lock, flags);
1449
			chip_bus_sync_unlock(desc);
1450
			return NULL;
1451
		}
L
Linus Torvalds 已提交
1452

1453 1454
		if (action->dev_id == dev_id)
			break;
1455
		action_ptr = &action->next;
1456
	}
1457

1458
	/* Found it - now remove it from the list of entries: */
1459
	*action_ptr = action->next;
1460

1461 1462
	irq_pm_remove_action(desc, action);

1463
	/* If this was the last handler, shut down the IRQ line: */
1464
	if (!desc->action) {
1465
		irq_settings_clr_disable_unlazy(desc);
1466
		irq_shutdown(desc);
1467 1468
		irq_release_resources(desc);
	}
1469

1470 1471 1472 1473 1474 1475
#ifdef CONFIG_SMP
	/* make sure affinity_hint is cleaned up */
	if (WARN_ON_ONCE(desc->affinity_hint))
		desc->affinity_hint = NULL;
#endif

1476
	raw_spin_unlock_irqrestore(&desc->lock, flags);
1477
	chip_bus_sync_unlock(desc);
1478 1479 1480 1481 1482

	unregister_handler_proc(irq, action);

	/* Make sure it's not being used on another CPU: */
	synchronize_irq(irq);
L
Linus Torvalds 已提交
1483

1484
#ifdef CONFIG_DEBUG_SHIRQ
1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496
	/*
	 * 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
1497
	}
1498
#endif
1499 1500

	if (action->thread) {
1501
		kthread_stop(action->thread);
1502
		put_task_struct(action->thread);
1503 1504 1505 1506
		if (action->secondary && action->secondary->thread) {
			kthread_stop(action->secondary->thread);
			put_task_struct(action->secondary->thread);
		}
1507 1508
	}

1509
	module_put(desc->owner);
1510
	kfree(action->secondary);
1511 1512 1513
	return action;
}

1514 1515 1516 1517 1518 1519 1520 1521 1522
/**
 *	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)
{
1523 1524 1525 1526
	struct irq_desc *desc = irq_to_desc(irq);

	if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
	    __free_irq(irq, act->dev_id);
1527
}
1528
EXPORT_SYMBOL_GPL(remove_irq);
1529

1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545
/**
 *	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.
 */
void free_irq(unsigned int irq, void *dev_id)
{
T
Thomas Gleixner 已提交
1546 1547
	struct irq_desc *desc = irq_to_desc(irq);

1548
	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
T
Thomas Gleixner 已提交
1549 1550
		return;

1551 1552 1553 1554 1555
#ifdef CONFIG_SMP
	if (WARN_ON(desc->affinity_notify))
		desc->affinity_notify = NULL;
#endif

1556
	kfree(__free_irq(irq, dev_id));
L
Linus Torvalds 已提交
1557 1558 1559 1560
}
EXPORT_SYMBOL(free_irq);

/**
1561
 *	request_threaded_irq - allocate an interrupt line
L
Linus Torvalds 已提交
1562
 *	@irq: Interrupt line to allocate
1563 1564
 *	@handler: Function to be called when the IRQ occurs.
 *		  Primary handler for threaded interrupts
T
Thomas Gleixner 已提交
1565 1566
 *		  If NULL and thread_fn != NULL the default
 *		  primary handler is installed
1567 1568
 *	@thread_fn: Function called from the irq handler thread
 *		    If NULL, no irq thread is created
L
Linus Torvalds 已提交
1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
 *	@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.
 *
1580
 *	If you want to set up a threaded irq handler for your device
J
Javi Merino 已提交
1581
 *	then you need to supply @handler and @thread_fn. @handler is
1582 1583 1584
 *	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
1585
 *	IRQ_WAKE_THREAD which will wake up the handler thread and run
1586 1587 1588
 *	@thread_fn. This split handler design is necessary to support
 *	shared interrupts.
 *
L
Linus Torvalds 已提交
1589 1590 1591 1592 1593 1594 1595 1596 1597
 *	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:
 *
1598
 *	IRQF_SHARED		Interrupt is shared
D
David Brownell 已提交
1599
 *	IRQF_TRIGGER_*		Specify active edge(s) or level
L
Linus Torvalds 已提交
1600 1601
 *
 */
1602 1603 1604
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
1605
{
1606
	struct irqaction *action;
1607
	struct irq_desc *desc;
1608
	int retval;
L
Linus Torvalds 已提交
1609 1610 1611 1612 1613 1614

	/*
	 * 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).
1615 1616 1617
	 *
	 * 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
1618
	 */
1619 1620 1621
	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
1622
		return -EINVAL;
1623

1624
	desc = irq_to_desc(irq);
1625
	if (!desc)
L
Linus Torvalds 已提交
1626
		return -EINVAL;
1627

1628 1629
	if (!irq_settings_can_request(desc) ||
	    WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1630
		return -EINVAL;
T
Thomas Gleixner 已提交
1631 1632 1633 1634 1635 1636

	if (!handler) {
		if (!thread_fn)
			return -EINVAL;
		handler = irq_default_primary_handler;
	}
L
Linus Torvalds 已提交
1637

1638
	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
L
Linus Torvalds 已提交
1639 1640 1641 1642
	if (!action)
		return -ENOMEM;

	action->handler = handler;
1643
	action->thread_fn = thread_fn;
L
Linus Torvalds 已提交
1644 1645 1646 1647
	action->flags = irqflags;
	action->name = devname;
	action->dev_id = dev_id;

1648
	chip_bus_lock(desc);
1649
	retval = __setup_irq(irq, desc, action);
1650
	chip_bus_sync_unlock(desc);
T
Thomas Gleixner 已提交
1651

1652 1653
	if (retval) {
		kfree(action->secondary);
1654
		kfree(action);
1655
	}
1656

1657
#ifdef CONFIG_DEBUG_SHIRQ_FIXME
1658
	if (!retval && (irqflags & IRQF_SHARED)) {
D
David Woodhouse 已提交
1659 1660 1661
		/*
		 * It's a shared IRQ -- the driver ought to be prepared for it
		 * to happen immediately, so let's make sure....
1662 1663
		 * 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
1664
		 */
1665
		unsigned long flags;
D
David Woodhouse 已提交
1666

1667
		disable_irq(irq);
1668
		local_irq_save(flags);
1669

1670
		handler(irq, dev_id);
1671

1672
		local_irq_restore(flags);
1673
		enable_irq(irq);
D
David Woodhouse 已提交
1674 1675
	}
#endif
L
Linus Torvalds 已提交
1676 1677
	return retval;
}
1678
EXPORT_SYMBOL(request_threaded_irq);
1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705

/**
 *	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)
{
	struct irq_desc *desc = irq_to_desc(irq);
	int ret;

	if (!desc)
		return -EINVAL;

1706
	if (irq_settings_is_nested_thread(desc)) {
1707 1708 1709 1710 1711 1712 1713 1714 1715
		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);
1716

1717
void enable_percpu_irq(unsigned int irq, unsigned int type)
1718 1719 1720 1721 1722 1723 1724 1725
{
	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;

1726 1727 1728 1729
	type &= IRQ_TYPE_SENSE_MASK;
	if (type != IRQ_TYPE_NONE) {
		int ret;

1730
		ret = __irq_set_trigger(desc, type);
1731 1732

		if (ret) {
1733
			WARN(1, "failed to set type for IRQ%d\n", irq);
1734 1735 1736 1737
			goto out;
		}
	}

1738
	irq_percpu_enable(desc, cpu);
1739
out:
1740 1741
	irq_put_desc_unlock(desc, flags);
}
1742
EXPORT_SYMBOL_GPL(enable_percpu_irq);
1743

1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768
/**
 * 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);

1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780
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);
}
1781
EXPORT_SYMBOL_GPL(disable_percpu_irq);
1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863

/*
 * 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);

	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);
}
1864
EXPORT_SYMBOL_GPL(free_percpu_irq);
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/**
 *	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;
	chip_bus_lock(desc);
	retval = __setup_irq(irq, desc, act);
	chip_bus_sync_unlock(desc);

	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
 *
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 *	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().
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 *
 *	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;
1923
	action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
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	action->name = devname;
	action->percpu_dev_id = dev_id;

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

	if (retval)
		kfree(action);

	return retval;
}
1936
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;
}
1983
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;
}
2029
EXPORT_SYMBOL_GPL(irq_set_irqchip_state);