/* * linux/kernel/irq/handle.c * * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar * Copyright (C) 2005-2006, Thomas Gleixner, Russell King * * This file contains the core interrupt handling code. * * Detailed information is available in Documentation/DocBook/genericirq * */ #include <linux/irq.h>#include <linux/module.h>#include <linux/random.h>#include <linux/interrupt.h>#include <linux/kernel_stat.h> #include "internals.h" /** * handle_bad_irq - handle spurious and unhandled irqs * @irq:       the interrupt number * @desc:      description of the interrupt * @regs:      pointer to a register structure * * Handles spurious and unhandled IRQ's. It also prints a debugmessage. */void fastcallhandle_bad_irq(unsigned int irq, struct irq_desc *desc){	print_irq_desc(irq, desc);	kstat_this_cpu.irqs[irq]++;	ack_bad_irq(irq);} /* * Linux has a controller-independent interrupt architecture. * Every controller has a 'controller-template', that is used * by the main code to do the right thing. Each driver-visible * interrupt source is transparently wired to the appropriate * controller. Thus drivers need not be aware of the * interrupt-controller. * * The code is designed to be easily extended with new/different * interrupt controllers, without having to do assembly magic or * having to touch the generic code. * * Controller mappings for all interrupt sources: */struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned = {	[0 ... NR_IRQS-1] = {		.status = IRQ_DISABLED,		.chip = &no_irq_chip,		.handle_irq = handle_bad_irq,		.depth = 1,		.lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),#ifdef CONFIG_SMP		.affinity = CPU_MASK_ALL#endif	}}; /* * What should we do if we get a hw irq event on an illegal vector? * Each architecture has to answer this themself. */static void ack_bad(unsigned int irq){	print_irq_desc(irq, irq_desc + irq);	ack_bad_irq(irq);} /* * NOP functions */static void noop(unsigned int irq){} static unsigned int noop_ret(unsigned int irq){	return 0;} /* * Generic no controller implementation */struct irq_chip no_irq_chip = {	.name		= "none",	.startup	= noop_ret,	.shutdown	= noop,	.enable		= noop,	.disable	= noop,	.ack		= ack_bad,	.end		= noop,}; /* * Generic dummy implementation which can be used for * real dumb interrupt sources */struct irq_chip dummy_irq_chip = {	.name		= "dummy",	.startup	= noop_ret,	.shutdown	= noop,	.enable		= noop,	.disable	= noop,	.ack		= noop,	.mask		= noop,	.unmask		= noop,	.end		= noop,}; /* * Special, empty irq handler: */irqreturn_t no_action(int cpl, void *dev_id){	return IRQ_NONE;} /** * handle_IRQ_event - irq action chain handler * @irq:	the interrupt number * @action:	the interrupt action chain for this irq * * Handles the action chain of an irq event */irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action){	irqreturn_t ret, retval = IRQ_NONE;	unsigned int status = 0; 	handle_dynamic_tick(action); 	if (!(action->flags & IRQF_DISABLED))		local_irq_enable_in_hardirq(); 	do {		ret = action->handler(irq, action->dev_id);		if (ret == IRQ_HANDLED)			status |= action->flags;		retval |= ret;		action = action->next;	} while (action); 	if (status & IRQF_SAMPLE_RANDOM)		add_interrupt_randomness(irq);	local_irq_disable(); 	return retval;} #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ/** * __do_IRQ - original all in one highlevel IRQ handler * @irq:	the interrupt number * * __do_IRQ handles all normal device IRQ's (the special * SMP cross-CPU interrupts have their own specific * handlers). * * This is the original x86 implementation which is used for every * interrupt type. */fastcall unsigned int __do_IRQ(unsigned int irq){	struct irq_desc *desc = irq_desc + irq;	struct irqaction *action;	unsigned int status; 	kstat_this_cpu.irqs[irq]++;	if (CHECK_IRQ_PER_CPU(desc->status)) {		irqreturn_t action_ret; 		/*		 * No locking required for CPU-local interrupts:		 */		if (desc->chip->ack)			desc->chip->ack(irq);		action_ret = handle_IRQ_event(irq, desc->action);		desc->chip->end(irq);		return 1;	} 	spin_lock(&desc->lock);	if (desc->chip->ack)		desc->chip->ack(irq);	/*	 * REPLAY is when Linux resends an IRQ that was dropped earlier	 * WAITING is used by probe to mark irqs that are being tested	 */	status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);	status |= IRQ_PENDING; /* we _want_ to handle it */ 	/*	 * If the IRQ is disabled for whatever reason, we cannot	 * use the action we have.	 */	action = NULL;	if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {		action = desc->action;		status &= ~IRQ_PENDING; /* we commit to handling */		status |= IRQ_INPROGRESS; /* we are handling it */	}	desc->status = status; 	/*	 * If there is no IRQ handler or it was disabled, exit early.	 * Since we set PENDING, if another processor is handling	 * a different instance of this same irq, the other processor	 * will take care of it.	 */	if (unlikely(!action))		goto out; 	/*	 * Edge triggered interrupts need to remember	 * pending events.	 * This applies to any hw interrupts that allow a second	 * instance of the same irq to arrive while we are in do_IRQ	 * or in the handler. But the code here only handles the _second_	 * instance of the irq, not the third or fourth. So it is mostly	 * useful for irq hardware that does not mask cleanly in an	 * SMP environment.	 */	for (;;) {		irqreturn_t action_ret; 		spin_unlock(&desc->lock); 		action_ret = handle_IRQ_event(irq, action);		if (!noirqdebug)			note_interrupt(irq, desc, action_ret); 		spin_lock(&desc->lock);		if (likely(!(desc->status & IRQ_PENDING)))			break;		desc->status &= ~IRQ_PENDING;	}	desc->status &= ~IRQ_INPROGRESS; out:	/*	 * The ->end() handler has to deal with interrupts which got	 * disabled while the handler was running.	 */	desc->chip->end(irq);	spin_unlock(&desc->lock); 	return 1;}#endif #ifdef CONFIG_TRACE_IRQFLAGS /* * lockdep: we want to handle all irq_desc locks as a single lock-class: */static struct lock_class_key irq_desc_lock_class; void early_init_irq_lock_class(void){	int i; 	for (i = 0; i < NR_IRQS; i++)		lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);} #endif