proc.c 6.0 KB
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/*
 * linux/kernel/irq/proc.c
 *
 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
 *
 * This file contains the /proc/irq/ handling code.
 */

#include <linux/irq.h>
#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/interrupt.h>

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#include "internals.h"

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static struct proc_dir_entry *root_irq_dir;
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#ifdef CONFIG_SMP

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static int irq_affinity_proc_show(struct seq_file *m, void *v)
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{
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	struct irq_desc *desc = irq_to_desc((long)m->private);
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	const struct cpumask *mask = &desc->affinity;
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#ifdef CONFIG_GENERIC_PENDING_IRQ
	if (desc->status & IRQ_MOVE_PENDING)
		mask = &desc->pending_mask;
#endif
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	seq_cpumask(m, mask);
	seq_putc(m, '\n');
	return 0;
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}

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#ifndef is_affinity_mask_valid
#define is_affinity_mask_valid(val) 1
#endif

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int no_irq_affinity;
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static ssize_t irq_affinity_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *pos)
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{
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	unsigned int irq = (int)(long)PDE(file->f_path.dentry->d_inode)->data;
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	cpumask_var_t new_value;
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	int err;
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	if (!irq_to_desc(irq)->chip->set_affinity || no_irq_affinity ||
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	    irq_balancing_disabled(irq))
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		return -EIO;

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	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
		return -ENOMEM;

	err = cpumask_parse_user(buffer, count, new_value);
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	if (err)
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		goto free_cpumask;
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	if (!is_affinity_mask_valid(new_value)) {
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		err = -EINVAL;
		goto free_cpumask;
	}
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	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
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	if (!cpumask_intersects(new_value, cpu_online_mask)) {
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		/* Special case for empty set - allow the architecture
		   code to set default SMP affinity. */
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		err = irq_select_affinity_usr(irq) ? -EINVAL : count;
	} else {
		irq_set_affinity(irq, new_value);
		err = count;
	}

free_cpumask:
	free_cpumask_var(new_value);
	return err;
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}

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static int irq_affinity_proc_open(struct inode *inode, struct file *file)
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{
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	return single_open(file, irq_affinity_proc_show, PDE(inode)->data);
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}

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static const struct file_operations irq_affinity_proc_fops = {
	.open		= irq_affinity_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= irq_affinity_proc_write,
};

static int default_affinity_show(struct seq_file *m, void *v)
{
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	seq_cpumask(m, irq_default_affinity);
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	seq_putc(m, '\n');
	return 0;
}

static ssize_t default_affinity_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
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{
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	cpumask_var_t new_value;
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	int err;
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	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
		return -ENOMEM;

	err = cpumask_parse_user(buffer, count, new_value);
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	if (err)
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		goto out;
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	if (!is_affinity_mask_valid(new_value)) {
		err = -EINVAL;
		goto out;
	}
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	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
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	if (!cpumask_intersects(new_value, cpu_online_mask)) {
		err = -EINVAL;
		goto out;
	}
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	cpumask_copy(irq_default_affinity, new_value);
	err = count;
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out:
	free_cpumask_var(new_value);
	return err;
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}
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static int default_affinity_open(struct inode *inode, struct file *file)
{
	return single_open(file, default_affinity_show, NULL);
}

static const struct file_operations default_affinity_proc_fops = {
	.open		= default_affinity_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= default_affinity_write,
};
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#endif

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static int irq_spurious_read(char *page, char **start, off_t off,
				  int count, int *eof, void *data)
{
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	struct irq_desc *desc = irq_to_desc((long) data);
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	return sprintf(page, "count %u\n"
			     "unhandled %u\n"
			     "last_unhandled %u ms\n",
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			desc->irq_count,
			desc->irqs_unhandled,
			jiffies_to_msecs(desc->last_unhandled));
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}

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#define MAX_NAMELEN 128

static int name_unique(unsigned int irq, struct irqaction *new_action)
{
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	struct irq_desc *desc = irq_to_desc(irq);
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	struct irqaction *action;
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	unsigned long flags;
	int ret = 1;
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	spin_lock_irqsave(&desc->lock, flags);
	for (action = desc->action ; action; action = action->next) {
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		if ((action != new_action) && action->name &&
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				!strcmp(new_action->name, action->name)) {
			ret = 0;
			break;
		}
	}
	spin_unlock_irqrestore(&desc->lock, flags);
	return ret;
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}

void register_handler_proc(unsigned int irq, struct irqaction *action)
{
	char name [MAX_NAMELEN];
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	struct irq_desc *desc = irq_to_desc(irq);
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	if (!desc->dir || action->dir || !action->name ||
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					!name_unique(irq, action))
		return;

	memset(name, 0, MAX_NAMELEN);
	snprintf(name, MAX_NAMELEN, "%s", action->name);

	/* create /proc/irq/1234/handler/ */
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	action->dir = proc_mkdir(name, desc->dir);
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}

#undef MAX_NAMELEN

#define MAX_NAMELEN 10

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void register_irq_proc(unsigned int irq, struct irq_desc *desc)
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{
	char name [MAX_NAMELEN];
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	struct proc_dir_entry *entry;
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	if (!root_irq_dir || (desc->chip == &no_irq_chip) || desc->dir)
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		return;

	memset(name, 0, MAX_NAMELEN);
	sprintf(name, "%d", irq);

	/* create /proc/irq/1234 */
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	desc->dir = proc_mkdir(name, root_irq_dir);
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#ifdef CONFIG_SMP
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	/* create /proc/irq/<irq>/smp_affinity */
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	proc_create_data("smp_affinity", 0600, desc->dir,
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			 &irq_affinity_proc_fops, (void *)(long)irq);
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#endif
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	entry = create_proc_entry("spurious", 0444, desc->dir);
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	if (entry) {
		entry->data = (void *)(long)irq;
		entry->read_proc = irq_spurious_read;
	}
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}

#undef MAX_NAMELEN

void unregister_handler_proc(unsigned int irq, struct irqaction *action)
{
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	if (action->dir) {
		struct irq_desc *desc = irq_to_desc(irq);
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		remove_proc_entry(action->dir->name, desc->dir);
	}
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}

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static void register_default_affinity_proc(void)
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{
#ifdef CONFIG_SMP
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	proc_create("irq/default_smp_affinity", 0600, NULL,
		    &default_affinity_proc_fops);
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#endif
}

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void init_irq_proc(void)
{
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	unsigned int irq;
	struct irq_desc *desc;
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	/* create /proc/irq */
	root_irq_dir = proc_mkdir("irq", NULL);
	if (!root_irq_dir)
		return;

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	register_default_affinity_proc();

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	/*
	 * Create entries for all existing IRQs.
	 */
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	for_each_irq_desc(irq, desc) {
		if (!desc)
			continue;

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		register_irq_proc(irq, desc);
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	}
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}