root/kernel/irq/proc.c

DEFINITIONS

1. irq_affinity_proc_show
2. irq_affinity_proc_write
3. irq_affinity_proc_open
4. default_affinity_show
5. default_affinity_write
6. default_affinity_open
7. irq_spurious_read
8. name_unique
9. register_handler_proc
10. register_irq_proc
11. unregister_handler_proc
12. register_default_affinity_proc
13. init_irq_proc

/*
 * 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>
#include <linux/seq_file.h>
#include <linux/interrupt.h>

#include "internals.h"

static struct proc_dir_entry *root_irq_dir;

#ifdef CONFIG_SMP

static int irq_affinity_proc_show(struct seq_file *m, void *v)
{
        struct irq_desc *desc = irq_desc + (long)m->private;
        cpumask_t *mask = &desc->affinity;

#ifdef CONFIG_GENERIC_PENDING_IRQ
        if (desc->status & IRQ_MOVE_PENDING)
                mask = &desc->pending_mask;
#endif
        seq_cpumask(m, mask);
        seq_putc(m, '\n');
        return 0;
}

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

int no_irq_affinity;
static ssize_t irq_affinity_proc_write(struct file *file,
                const char __user *buffer, size_t count, loff_t *pos)
{
        unsigned int irq = (int)(long)PDE(file->f_path.dentry->d_inode)->data;
        cpumask_t new_value;
        int err;

        if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
            irq_balancing_disabled(irq))
                return -EIO;

        err = cpumask_parse_user(buffer, count, new_value);
        if (err)
                return err;

        if (!is_affinity_mask_valid(new_value))
                return -EINVAL;

        /*
         * 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.
         */
        if (!cpus_intersects(new_value, cpu_online_map))
                /* Special case for empty set - allow the architecture
                   code to set default SMP affinity. */
                return irq_select_affinity(irq) ? -EINVAL : count;

        irq_set_affinity(irq, new_value);

        return count;
}

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

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)
{
        seq_cpumask(m, &irq_default_affinity);
        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)
{
        cpumask_t new_value;
        int err;

        err = cpumask_parse_user(buffer, count, new_value);
        if (err)
                return err;

        if (!is_affinity_mask_valid(new_value))
                return -EINVAL;

        /*
         * 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.
         */
        if (!cpus_intersects(new_value, cpu_online_map))
                return -EINVAL;

        irq_default_affinity = new_value;

        return count;
}

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,
};
#endif

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

#define MAX_NAMELEN 128

static int name_unique(unsigned int irq, struct irqaction *new_action)
{
        struct irq_desc *desc = irq_desc + irq;
        struct irqaction *action;
        unsigned long flags;
        int ret = 1;

        spin_lock_irqsave(&desc->lock, flags);
        for (action = desc->action ; action; action = action->next) {
                if ((action != new_action) && action->name &&
                                !strcmp(new_action->name, action->name)) {
                        ret = 0;
                        break;
                }
        }
        spin_unlock_irqrestore(&desc->lock, flags);
        return ret;
}

void register_handler_proc(unsigned int irq, struct irqaction *action)
{
        char name [MAX_NAMELEN];

        if (!irq_desc[irq].dir || action->dir || !action->name ||
                                        !name_unique(irq, action))
                return;

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

        /* create /proc/irq/1234/handler/ */
        action->dir = proc_mkdir(name, irq_desc[irq].dir);
}

#undef MAX_NAMELEN

#define MAX_NAMELEN 10

void register_irq_proc(unsigned int irq)
{
        char name [MAX_NAMELEN];
        struct proc_dir_entry *entry;

        if (!root_irq_dir ||
                (irq_desc[irq].chip == &no_irq_chip) ||
                        irq_desc[irq].dir)
                return;

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

        /* create /proc/irq/1234 */
        irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);

#ifdef CONFIG_SMP
        /* create /proc/irq/<irq>/smp_affinity */
        proc_create_data("smp_affinity", 0600, irq_desc[irq].dir,
                         &irq_affinity_proc_fops, (void *)(long)irq);
#endif

        entry = create_proc_entry("spurious", 0444, irq_desc[irq].dir);
        if (entry) {
                entry->data = (void *)(long)irq;
                entry->read_proc = irq_spurious_read;
        }
}

#undef MAX_NAMELEN

void unregister_handler_proc(unsigned int irq, struct irqaction *action)
{
        if (action->dir)
                remove_proc_entry(action->dir->name, irq_desc[irq].dir);
}

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

void init_irq_proc(void)
{
        int i;

        /* create /proc/irq */
        root_irq_dir = proc_mkdir("irq", NULL);
        if (!root_irq_dir)
                return;

        register_default_affinity_proc();

        /*
         * Create entries for all existing IRQs.
         */
        for (i = 0; i < NR_IRQS; i++)
                register_irq_proc(i);
}