kdebugfs.c

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/*
 * Architecture specific debugfs files
 *
 * Copyright (C) 2007, Intel Corp.
 *  Huang Ying <[email protected]>
 *
 * This file is released under the GPLv2.
 */
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/stat.h>
#include <linux/io.h>
#include <linux/mm.h>

#include <asm/setup.h>

struct dentry *arch_debugfs_dir;
EXPORT_SYMBOL(arch_debugfs_dir);

#ifdef CONFIG_DEBUG_BOOT_PARAMS
struct setup_data_node {
    u64 paddr;
    u32 type;
    u32 len;
};

static ssize_t setup_data_read(struct file *file, char __user *user_buf,
                   size_t count, loff_t *ppos)
{
    struct setup_data_node *node = file->private_data;
    unsigned long remain;
    loff_t pos = *ppos;
    struct page *pg;
    void *p;
    u64 pa;

    if (pos < 0)
        return -EINVAL;

    if (pos >= node->len)
        return 0;

    if (count > node->len - pos)
        count = node->len - pos;

    pa = node->paddr + sizeof(struct setup_data) + pos;
    pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
    if (PageHighMem(pg)) {
        p = ioremap_cache(pa, count);
        if (!p)
            return -ENXIO;
    } else
        p = __va(pa);

    remain = copy_to_user(user_buf, p, count);

    if (PageHighMem(pg))
        iounmap(p);

    if (remain)
        return -EFAULT;

    *ppos = pos + count;

    return count;
}

static const struct file_operations fops_setup_data = {
    .read       = setup_data_read,
    .open       = simple_open,
    .llseek     = default_llseek,
};

static int __init
create_setup_data_node(struct dentry *parent, int no,
               struct setup_data_node *node)
{
    struct dentry *d, *type, *data;
    char buf[16];

    sprintf(buf, "%d", no);
    d = debugfs_create_dir(buf, parent);
    if (!d)
        return -ENOMEM;

    type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
    if (!type)
        goto err_dir;

    data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
    if (!data)
        goto err_type;

    return 0;

err_type:
    debugfs_remove(type);
err_dir:
    debugfs_remove(d);
    return -ENOMEM;
}

static int __init create_setup_data_nodes(struct dentry *parent)
{
    struct setup_data_node *node;
    struct setup_data *data;
    int error;
    struct dentry *d;
    struct page *pg;
    u64 pa_data;
    int no = 0;

    d = debugfs_create_dir("setup_data", parent);
    if (!d)
        return -ENOMEM;

    pa_data = boot_params.hdr.setup_data;

    while (pa_data) {
        node = kmalloc(sizeof(*node), GFP_KERNEL);
        if (!node) {
            error = -ENOMEM;
            goto err_dir;
        }

        pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
        if (PageHighMem(pg)) {
            data = ioremap_cache(pa_data, sizeof(*data));
            if (!data) {
                kfree(node);
                error = -ENXIO;
                goto err_dir;
            }
        } else
            data = __va(pa_data);

        node->paddr = pa_data;
        node->type = data->type;
        node->len = data->len;
        error = create_setup_data_node(d, no, node);
        pa_data = data->next;

        if (PageHighMem(pg))
            iounmap(data);
        if (error)
            goto err_dir;
        no++;
    }

    return 0;

err_dir:
    debugfs_remove(d);
    return error;
}

static struct debugfs_blob_wrapper boot_params_blob = {
    .data       = &boot_params,
    .size       = sizeof(boot_params),
};

static int __init boot_params_kdebugfs_init(void)
{
    struct dentry *dbp, *version, *data;
    int error = -ENOMEM;

    dbp = debugfs_create_dir("boot_params", NULL);
    if (!dbp)
        return -ENOMEM;

    version = debugfs_create_x16("version", S_IRUGO, dbp,
                     &boot_params.hdr.version);
    if (!version)
        goto err_dir;

    data = debugfs_create_blob("data", S_IRUGO, dbp,
                   &boot_params_blob);
    if (!data)
        goto err_version;

    error = create_setup_data_nodes(dbp);
    if (error)
        goto err_data;

    return 0;

err_data:
    debugfs_remove(data);
err_version:
    debugfs_remove(version);
err_dir:
    debugfs_remove(dbp);
    return error;
}
#endif /* CONFIG_DEBUG_BOOT_PARAMS */

static int __init arch_kdebugfs_init(void)
{
    int error = 0;

    arch_debugfs_dir = debugfs_create_dir("x86", NULL);
    if (!arch_debugfs_dir)
        return -ENOMEM;

#ifdef CONFIG_DEBUG_BOOT_PARAMS
    error = boot_params_kdebugfs_init();
#endif

    return error;
}
arch_initcall(arch_kdebugfs_init);