asids-debugfs.c

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/*
 * debugfs ops for process ASIDs
 *
 *  Copyright (C) 2000, 2001  Paolo Alberelli
 *  Copyright (C) 2003 - 2008  Paul Mundt
 *  Copyright (C) 2003, 2004  Richard Curnow
 *
 * Provides a debugfs file that lists out the ASIDs currently associated
 * with the processes.
 *
 * In the SH-5 case, if the DM.PC register is examined through the debug
 * link, this shows ASID + PC. To make use of this, the PID->ASID
 * relationship needs to be known. This is primarily for debugging.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>

static int asids_seq_show(struct seq_file *file, void *iter)
{
    struct task_struct *p;

    read_lock(&tasklist_lock);

    for_each_process(p) {
        int pid = p->pid;

        if (unlikely(!pid))
            continue;

        if (p->mm)
            seq_printf(file, "%5d : %04lx\n", pid,
                   cpu_asid(smp_processor_id(), p->mm));
    }

    read_unlock(&tasklist_lock);

    return 0;
}

static int asids_debugfs_open(struct inode *inode, struct file *file)
{
    return single_open(file, asids_seq_show, inode->i_private);
}

static const struct file_operations asids_debugfs_fops = {
    .owner      = THIS_MODULE,
    .open       = asids_debugfs_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static int __init asids_debugfs_init(void)
{
    struct dentry *asids_dentry;

    asids_dentry = debugfs_create_file("asids", S_IRUSR, arch_debugfs_dir,
                       NULL, &asids_debugfs_fops);
    if (!asids_dentry)
        return -ENOMEM;
    if (IS_ERR(asids_dentry))
        return PTR_ERR(asids_dentry);

    return 0;
}
module_init(asids_debugfs_init);

MODULE_LICENSE("GPL v2");