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最新推荐文章于 2024-08-12 17:01:39 发布

转载最新推荐文章于 2024-08-12 17:01:39 发布

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https://blog.youkuaiyun.com/windeal3203/article/details/44594783

https://blog.youkuaiyun.com/baidu_31504167/article/details/101308229

No irq handler for vector (irq -1)：

https://my.oschina.net/u/2854094/blog/815878

http://ilinuxkernel.com/?p=1192

cat /proc/interrupts查看中断信息：

第1列表示中断号，第2-5列表示该中断在该CPU上产生的次数，第6列表示处理这个中断的中断控制器，第7列表示与这个中断相关的设备名字。

设备驱动程序负责为管理的设备提供中断处理程序，并向系统注册。从设备发出中断信号，到处理器最终调用中断处理程序，期间会经过很多步骤，这个过程构成了中断处理框架。

/*
 * do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */
__visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
{
	struct pt_regs *old_regs = set_irq_regs(regs);

	/* high bit used in ret_from_ code  */
	unsigned vector = ~regs->orig_ax;
	unsigned irq;

	irq_enter();
	exit_idle();

	irq = __this_cpu_read(vector_irq[vector]);//获取中断号irq

	if (!handle_irq(irq, regs)) {
		ack_APIC_irq();

		if (irq != VECTOR_RETRIGGERED) {
			pr_emerg_ratelimited("%s: %d.%d No irq handler for vector (irq %d)\n",
					     __func__, smp_processor_id(),
					     vector, irq);
		} else {
			__this_cpu_write(vector_irq[vector], VECTOR_UNDEFINED);
		}
	}

	irq_exit();

	set_irq_regs(old_regs);
	return 1;
}

从别处看，好像中断号找不到的时候会报这个错： pr_emerg_ratelimited("%s: %d.%d No irq handler for vector (irq %d)\n", __func__, smp_processor_id(), vector, irq); 就是网上经常出现的：No irq handler for vector (irq -1)：

smp_processor_id()：表示在哪个CPU上

static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs)
{
	struct pt_regs *old_regs;

	old_regs = get_irq_regs();
	this_cpu_write(irq_regs, new_regs);

	return old_regs;
}


static inline struct pt_regs *get_irq_regs(void)
{
	return this_cpu_read(irq_regs);
}

https://blog.youkuaiyun.com/cc289123557/article/details/52974200

http://www.wowotech.net/linux_kenrel/interrupt_descriptor.html

https://www.cnblogs.com/lifexy/p/7506504.html

handle_irq

根据中断号irq，取得中断描述符结构体。

bool handle_irq(unsigned irq, struct pt_regs *regs)
{
	struct irq_desc *desc;

	stack_overflow_check(regs);

	desc = irq_to_desc(irq);
	if (unlikely(!desc))//判断是否为空
		return false;

	generic_handle_irq_desc(irq, desc);
	return true;
}

irq_to_desc()根据中断号irq获取中断描述符desc

在内核中，irq_desc的组织方式有两种，根据宏CONFIG_SPARSE_IRQ是否定义来决定。

1.redix_tree方式，这是以基数树的方式来组织irq_desc；

2.数组的方式，NR_IRQS表示支持的最多的irq数量。

本文只讨论数组方式。

irq_desc irq_desc

struct irq_desc *irq_to_desc(unsigned int irq)
{
	return (irq < NR_IRQS) ? irq_desc + irq : NULL;
}

#ifndef CONFIG_SPARSE_IRQ
extern struct irq_desc irq_desc[NR_IRQS];
#endif

linux-4.1.45\kernel\irq\irqdesc.c
struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
	[0 ... NR_IRQS-1] = {
		.handle_irq	= handle_bad_irq,
		.depth		= 1,
		.lock		= __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
	}
};

基数树的方式：

struct irq_desc *irq_to_desc(unsigned int irq)
{
	return radix_tree_lookup(&irq_desc_tree, irq);
}

generic_handle_irq_desc


/*
 * Architectures call this to let the generic IRQ layer
 * handle an interrupt. If the descriptor is attached to an
 * irqchip-style controller then we call the ->handle_irq() handler,
 * and it calls __do_IRQ() if it's attached to an irqtype-style controller.
 */
static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *desc)
{
	desc->handle_irq(irq, desc);
}

irq_desc的初始化：

desc->handle_irq最终是指向了handle_level_irq。

irq的舒初始化包括两个函数，early_irq_init()，init_IRQ()。

这两个函数是在main.c中的start_kernel()中调用的，先调用early_irq_init()，紧接着调用init_IRQ()。


int __init early_irq_init(void)
{
	int count, i, node = first_online_node;
	struct irq_desc *desc;

	init_irq_default_affinity();

	printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);//打印出NR_IRQS数量

	desc = irq_desc;
	count = ARRAY_SIZE(irq_desc);//这个count是不是就是NR_IRQS呀

	for (i = 0; i < count; i++) {
		desc[i].kstat_irqs = alloc_percpu(unsigned int);
		alloc_masks(&desc[i], GFP_KERNEL, node);
		raw_spin_lock_init(&desc[i].lock);
		lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
		desc_set_defaults(i, &desc[i], node, NULL);
	}
	return arch_early_irq_init();
}


static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
		struct module *owner)
{
	int cpu;

	desc->irq_data.common = &desc->irq_common_data;
	desc->irq_data.irq = irq;
	desc->irq_data.chip = &no_irq_chip;
	desc->irq_data.chip_data = NULL;
	desc->irq_data.handler_data = NULL;
	desc->irq_data.msi_desc = NULL;
	irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
	irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
	desc->handle_irq = handle_bad_irq;
	desc->depth = 1;
	desc->irq_count = 0;
	desc->irqs_unhandled = 0;
	desc->name = NULL;
	desc->owner = owner;
	for_each_possible_cpu(cpu)
		*per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
	desc_smp_init(desc, node);
}

linux-4.1.45\arch\x86\kernel\irqinit.c
void __init init_IRQ(void)
{
	int i;

	/*
	 * On cpu 0, Assign IRQ0_VECTOR..IRQ15_VECTOR's to IRQ 0..15.
	 * If these IRQ's are handled by legacy interrupt-controllers like PIC,
	 * then this configuration will likely be static after the boot. If
	 * these IRQ's are handled by more mordern controllers like IO-APIC,
	 * then this vector space can be freed and re-used dynamically as the
	 * irq's migrate etc.
	 */
        /*建立0-15号软中断irq与irq_chip，desc->handle_irq之间的关系*/
	for (i = 0; i < nr_legacy_irqs(); i++)
		per_cpu(vector_irq, 0)[IRQ0_VECTOR + i] = i;

	x86_init.irqs.intr_init();
}

linux-4.1.45\arch\x86\kernel\x86_init.c
/*
 * The platform setup functions are preset with the default functions
 * for standard PC hardware.
 */
struct x86_init_ops x86_init __initdata = {

	...
	.irqs = {
		.pre_vector_init	= init_ISA_irqs,
		.intr_init		= native_init_IRQ,
		.trap_init		= x86_init_noop,
	},
	...
};

linux-4.1.45\arch\x86\kernel\irqinit.c
void __init native_init_IRQ(void)
{
	int i;

	/* Execute any quirks before the call gates are initialised: */
	x86_init.irqs.pre_vector_init();

	apic_intr_init();

	/*
	 * Cover the whole vector space, no vector can escape
	 * us. (some of these will be overridden and become
	 * 'special' SMP interrupts)
	 */
	i = FIRST_EXTERNAL_VECTOR;
#ifndef CONFIG_X86_LOCAL_APIC
#define first_system_vector NR_VECTORS
#endif
	for_each_clear_bit_from(i, used_vectors, first_system_vector) {
		/* IA32_SYSCALL_VECTOR could be used in trap_init already. */
		set_intr_gate(i, irq_entries_start +
				8 * (i - FIRST_EXTERNAL_VECTOR));
	}
#ifdef CONFIG_X86_LOCAL_APIC
	for_each_clear_bit_from(i, used_vectors, NR_VECTORS)
		set_intr_gate(i, spurious_interrupt);
#endif

	if (!acpi_ioapic && !of_ioapic && nr_legacy_irqs())
		setup_irq(2, &irq2);

#ifdef CONFIG_X86_32
	irq_ctx_init(smp_processor_id());
#endif
}


void __init init_ISA_irqs(void)
{
	struct irq_chip *chip = legacy_pic->chip;
	int i;

#if defined(CONFIG_X86_64) || defined(CONFIG_X86_LOCAL_APIC)
	init_bsp_APIC();
#endif
	legacy_pic->init(0);

	for (i = 0; i < nr_legacy_irqs(); i++)
		irq_set_chip_and_handler(i, chip, handle_level_irq);
}

linux-4.1.45\include\linux\irq.h
static inline void irq_set_chip_and_handler(unsigned int irq, struct irq_chip *chip,
					    irq_flow_handler_t handle)
{
	irq_set_chip_and_handler_name(irq, chip, handle, NULL);
}

linux-4.1.45\kernel\irq\chip.c
void
irq_set_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
			      irq_flow_handler_t handle, const char *name)
{
	irq_set_chip(irq, chip);
	__irq_set_handler(irq, handle, 0, name);
}

linux-4.1.45\kernel\irq\chip.c
void
__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
		  const char *name)
{
	unsigned long flags;
	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);

	if (!desc)
		return;

	if (!handle) {
		handle = handle_bad_irq;
	} else {
		struct irq_data *irq_data = &desc->irq_data;
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
		/*
		 * With hierarchical domains we might run into a
		 * situation where the outermost chip is not yet set
		 * up, but the inner chips are there.  Instead of
		 * bailing we install the handler, but obviously we
		 * cannot enable/startup the interrupt at this point.
		 */
		while (irq_data) {
			if (irq_data->chip != &no_irq_chip)
				break;
			/*
			 * Bail out if the outer chip is not set up
			 * and the interrrupt supposed to be started
			 * right away.
			 */
			if (WARN_ON(is_chained))
				goto out;
			/* Try the parent */
			irq_data = irq_data->parent_data;
		}
#endif
		if (WARN_ON(!irq_data || irq_data->chip == &no_irq_chip))
			goto out;
	}

	/* Uninstall? */
	if (handle == handle_bad_irq) {
		if (desc->irq_data.chip != &no_irq_chip)
			mask_ack_irq(desc);
		irq_state_set_disabled(desc);
		desc->depth = 1;
	}
	desc->handle_irq = handle;
	desc->name = name;

	if (handle != handle_bad_irq && is_chained) {
		irq_settings_set_noprobe(desc);
		irq_settings_set_norequest(desc);
		irq_settings_set_nothread(desc);
		irq_startup(desc, true);
	}
out:
	irq_put_desc_busunlock(desc, flags);
}

电平类型中断


/**
 *	handle_level_irq - Level type irq handler
 *	@irq:	the interrupt number
 *	@desc:	the interrupt description structure for this irq
 *
 *	Level type interrupts are active as long as the hardware line has
 *	the active level. This may require to mask the interrupt and unmask
 *	it after the associated handler has acknowledged the device, so the
 *	interrupt line is back to inactive.
 */
void
handle_level_irq(unsigned int irq, struct irq_desc *desc)
{
	raw_spin_lock(&desc->lock);
	mask_ack_irq(desc);//屏蔽及确认中断

	if (!irq_may_run(desc))
		goto out_unlock;

	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
	kstat_incr_irqs_this_cpu(irq, desc);//更新与中断相关的统计量，比如统计某一CPU上中断发生次数

	/*
	 * If its disabled or no action available
	 * keep it masked and get out of here
	 */
	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
		desc->istate |= IRQS_PENDING;
		goto out_unlock;
	}

	handle_irq_event(desc);

	cond_unmask_irq(desc);

out_unlock:
	raw_spin_unlock(&desc->lock);
}


irqreturn_t handle_irq_event(struct irq_desc *desc)
{
	struct irqaction *action = desc->action;
	irqreturn_t ret;

	desc->istate &= ~IRQS_PENDING;
	irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);//将当前中断线设置IRQD_IRQ_INPROGRESS状态，表明该中断线上一个中断正在被处理。
	raw_spin_unlock(&desc->lock);

	ret = handle_irq_event_percpu(desc, action);

	raw_spin_lock(&desc->lock);
	irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
	return ret;
}


irqreturn_t
handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)
{
	irqreturn_t retval = IRQ_NONE;
	unsigned int flags = 0, irq = desc->irq_data.irq;

	do {
		irqreturn_t res;

		trace_irq_handler_entry(irq, action);//驱动注册的中断处理函数
		res = action->handler(irq, action->dev_id);
		trace_irq_handler_exit(irq, action, res);

		if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n",
			      irq, action->handler))
			local_irq_disable();

		switch (res) {
		case IRQ_WAKE_THREAD:
			/*
			 * Catch drivers which return WAKE_THREAD but
			 * did not set up a thread function
			 */
			if (unlikely(!action->thread_fn)) {
				warn_no_thread(irq, action);
				break;
			}

			__irq_wake_thread(desc, action);

			/* Fall through to add to randomness */
		case IRQ_HANDLED:
			flags |= action->flags;
			break;

		default:
			break;
		}

		retval |= res;
		action = action->next;
	} while (action);

	add_interrupt_randomness(irq, flags);

	if (!noirqdebug)
		note_interrupt(irq, desc, retval);
	return retval;
}

/*
 * Exit an interrupt context. Process softirqs if needed and possible:
 */
void irq_exit(void)
{
#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
	local_irq_disable();
#else
	WARN_ON_ONCE(!irqs_disabled());
#endif

	account_irq_exit_time(current);
	preempt_count_sub(HARDIRQ_OFFSET);
	if (!in_interrupt() && local_softirq_pending())
		invoke_softirq();//触发软中断

	tick_irq_exit();
	rcu_irq_exit();
	trace_hardirq_exit(); /* must be last! */
}


/*
 * Core internal functions to deal with irq descriptors
 *
 * This include will move to kernel/irq once we cleaned up the tree.
 * For now it's included from <linux/irq.h>
 */

struct irq_affinity_notify;
struct proc_dir_entry;
struct module;
struct irq_desc;
struct irq_domain;
struct pt_regs;

/**
 * struct irq_desc - interrupt descriptor
 * @irq_common_data:	per irq and chip data passed down to chip functions
 * @kstat_irqs:		irq stats per cpu
 * @handle_irq:		highlevel irq-events handler
 * @preflow_handler:	handler called before the flow handler (currently used by sparc)
 * @action:		the irq action chain
 * @status:		status information
 * @core_internal_state__do_not_mess_with_it: core internal status information
 * @depth:		disable-depth, for nested irq_disable() calls
 * @wake_depth:		enable depth, for multiple irq_set_irq_wake() callers
 * @irq_count:		stats field to detect stalled irqs
 * @last_unhandled:	aging timer for unhandled count
 * @irqs_unhandled:	stats field for spurious unhandled interrupts
 * @threads_handled:	stats field for deferred spurious detection of threaded handlers
 * @threads_handled_last: comparator field for deferred spurious detection of theraded handlers
 * @lock:		locking for SMP
 * @affinity_hint:	hint to user space for preferred irq affinity
 * @affinity_notify:	context for notification of affinity changes
 * @pending_mask:	pending rebalanced interrupts
 * @threads_oneshot:	bitfield to handle shared oneshot threads
 * @threads_active:	number of irqaction threads currently running
 * @wait_for_threads:	wait queue for sync_irq to wait for threaded handlers
 * @nr_actions:		number of installed actions on this descriptor
 * @no_suspend_depth:	number of irqactions on a irq descriptor with
 *			IRQF_NO_SUSPEND set
 * @force_resume_depth:	number of irqactions on a irq descriptor with
 *			IRQF_FORCE_RESUME set
 * @dir:		/proc/irq/ procfs entry
 * @name:		flow handler name for /proc/interrupts output
 */
struct irq_desc {
	struct irq_common_data	irq_common_data;
	struct irq_data		irq_data;
	unsigned int __percpu	*kstat_irqs;
	irq_flow_handler_t	handle_irq;
#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
	irq_preflow_handler_t	preflow_handler;
#endif
	struct irqaction	*action;	/* IRQ action list */
	unsigned int		status_use_accessors;
	unsigned int		core_internal_state__do_not_mess_with_it;
	unsigned int		depth;		/* nested irq disables */
	unsigned int		wake_depth;	/* nested wake enables */
	unsigned int		irq_count;	/* For detecting broken IRQs */
	unsigned long		last_unhandled;	/* Aging timer for unhandled count */
	unsigned int		irqs_unhandled;
	atomic_t		threads_handled;
	int			threads_handled_last;
	raw_spinlock_t		lock;
	struct cpumask		*percpu_enabled;
#ifdef CONFIG_SMP
	const struct cpumask	*affinity_hint;
	struct irq_affinity_notify *affinity_notify;
#ifdef CONFIG_GENERIC_PENDING_IRQ
	cpumask_var_t		pending_mask;
#endif
#endif
	unsigned long		threads_oneshot;
	atomic_t		threads_active;
	wait_queue_head_t       wait_for_threads;
#ifdef CONFIG_PM_SLEEP
	unsigned int		nr_actions;
	unsigned int		no_suspend_depth;
	unsigned int		cond_suspend_depth;
	unsigned int		force_resume_depth;
#endif
#ifdef CONFIG_PROC_FS
	struct proc_dir_entry	*dir;
#endif
	int			parent_irq;
	struct module		*owner;
	const char		*name;
} ____cacheline_internodealigned_in_smp;


/**
 * struct irqaction - per interrupt action descriptor
 * @handler:	interrupt handler function
 * @name:	name of the device
 * @dev_id:	cookie to identify the device
 * @percpu_dev_id:	cookie to identify the device
 * @next:	pointer to the next irqaction for shared interrupts
 * @irq:	interrupt number
 * @flags:	flags (see IRQF_* above)
 * @thread_fn:	interrupt handler function for threaded interrupts
 * @thread:	thread pointer for threaded interrupts
 * @thread_flags:	flags related to @thread
 * @thread_mask:	bitmask for keeping track of @thread activity
 * @dir:	pointer to the proc/irq/NN/name entry
 */
struct irqaction {
	irq_handler_t		handler;
	void			*dev_id;
	void __percpu		*percpu_dev_id;
	struct irqaction	*next;
	irq_handler_t		thread_fn;
	struct task_struct	*thread;
	unsigned int		irq;
	unsigned int		flags;
	unsigned long		thread_flags;
	unsigned long		thread_mask;
	const char		*name;
	struct proc_dir_entry	*dir;
} ____cacheline_internodealigned_in_smp;