LXR linux/arch/x86/kernel/kdebugfs.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Architecture specific debugfs files
   4 *
   5 * Copyright (C) 2007, Intel Corp.
   6 *      Huang Ying <ying.huang@intel.com>
   7 */
   8#include <linux/debugfs.h>
   9#include <linux/uaccess.h>
  10#include <linux/export.h>
  11#include <linux/slab.h>
  12#include <linux/init.h>
  13#include <linux/stat.h>
  14#include <linux/io.h>
  15#include <linux/mm.h>
  16
  17#include <asm/setup.h>
  18
  19struct dentry *arch_debugfs_dir;
  20EXPORT_SYMBOL(arch_debugfs_dir);
  21
  22#ifdef CONFIG_DEBUG_BOOT_PARAMS
  23struct setup_data_node {
  24        u64 paddr;
  25        u32 type;
  26        u32 len;
  27};
  28
  29static ssize_t setup_data_read(struct file *file, char __user *user_buf,
  30                               size_t count, loff_t *ppos)
  31{
  32        struct setup_data_node *node = file->private_data;
  33        unsigned long remain;
  34        loff_t pos = *ppos;
  35        void *p;
  36        u64 pa;
  37
  38        if (pos < 0)
  39                return -EINVAL;
  40
  41        if (pos >= node->len)
  42                return 0;
  43
  44        if (count > node->len - pos)
  45                count = node->len - pos;
  46
  47        pa = node->paddr + sizeof(struct setup_data) + pos;
  48        p = memremap(pa, count, MEMREMAP_WB);
  49        if (!p)
  50                return -ENOMEM;
  51
  52        remain = copy_to_user(user_buf, p, count);
  53
  54        memunmap(p);
  55
  56        if (remain)
  57                return -EFAULT;
  58
  59        *ppos = pos + count;
  60
  61        return count;
  62}
  63
  64static const struct file_operations fops_setup_data = {
  65        .read           = setup_data_read,
  66        .open           = simple_open,
  67        .llseek         = default_llseek,
  68};
  69
  70static void __init
  71create_setup_data_node(struct dentry *parent, int no,
  72                       struct setup_data_node *node)
  73{
  74        struct dentry *d;
  75        char buf[16];
  76
  77        sprintf(buf, "%d", no);
  78        d = debugfs_create_dir(buf, parent);
  79
  80        debugfs_create_x32("type", S_IRUGO, d, &node->type);
  81        debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
  82}
  83
  84static int __init create_setup_data_nodes(struct dentry *parent)
  85{
  86        struct setup_data_node *node;
  87        struct setup_data *data;
  88        int error;
  89        struct dentry *d;
  90        u64 pa_data;
  91        int no = 0;
  92
  93        d = debugfs_create_dir("setup_data", parent);
  94
  95        pa_data = boot_params.hdr.setup_data;
  96
  97        while (pa_data) {
  98                node = kmalloc(sizeof(*node), GFP_KERNEL);
  99                if (!node) {
 100                        error = -ENOMEM;
 101                        goto err_dir;
 102                }
 103
 104                data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
 105                if (!data) {
 106                        kfree(node);
 107                        error = -ENOMEM;
 108                        goto err_dir;
 109                }
 110
 111                node->paddr = pa_data;
 112                node->type = data->type;
 113                node->len = data->len;
 114                create_setup_data_node(d, no, node);
 115                pa_data = data->next;
 116
 117                memunmap(data);
 118                no++;
 119        }
 120
 121        return 0;
 122
 123err_dir:
 124        debugfs_remove_recursive(d);
 125        return error;
 126}
 127
 128static struct debugfs_blob_wrapper boot_params_blob = {
 129        .data           = &boot_params,
 130        .size           = sizeof(boot_params),
 131};
 132
 133static int __init boot_params_kdebugfs_init(void)
 134{
 135        struct dentry *dbp;
 136        int error;
 137
 138        dbp = debugfs_create_dir("boot_params", arch_debugfs_dir);
 139
 140        debugfs_create_x16("version", S_IRUGO, dbp, &boot_params.hdr.version);
 141        debugfs_create_blob("data", S_IRUGO, dbp, &boot_params_blob);
 142
 143        error = create_setup_data_nodes(dbp);
 144        if (error)
 145                debugfs_remove_recursive(dbp);
 146
 147        return error;
 148}
 149#endif /* CONFIG_DEBUG_BOOT_PARAMS */
 150
 151static int __init arch_kdebugfs_init(void)
 152{
 153        int error = 0;
 154
 155        arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 156
 157#ifdef CONFIG_DEBUG_BOOT_PARAMS
 158        error = boot_params_kdebugfs_init();
 159#endif
 160
 161        return error;
 162}
 163arch_initcall(arch_kdebugfs_init);
 164