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 + pos;
  48
  49        /* Is it direct data or invalid indirect one? */
  50        if (!(node->type & SETUP_INDIRECT) || node->type == SETUP_INDIRECT)
  51                pa += sizeof(struct setup_data);
  52
  53        p = memremap(pa, count, MEMREMAP_WB);
  54        if (!p)
  55                return -ENOMEM;
  56
  57        remain = copy_to_user(user_buf, p, count);
  58
  59        memunmap(p);
  60
  61        if (remain)
  62                return -EFAULT;
  63
  64        *ppos = pos + count;
  65
  66        return count;
  67}
  68
  69static const struct file_operations fops_setup_data = {
  70        .read           = setup_data_read,
  71        .open           = simple_open,
  72        .llseek         = default_llseek,
  73};
  74
  75static void __init
  76create_setup_data_node(struct dentry *parent, int no,
  77                       struct setup_data_node *node)
  78{
  79        struct dentry *d;
  80        char buf[16];
  81
  82        sprintf(buf, "%d", no);
  83        d = debugfs_create_dir(buf, parent);
  84
  85        debugfs_create_x32("type", S_IRUGO, d, &node->type);
  86        debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
  87}
  88
  89static int __init create_setup_data_nodes(struct dentry *parent)
  90{
  91        struct setup_data_node *node;
  92        struct setup_data *data;
  93        int error;
  94        struct dentry *d;
  95        u64 pa_data;
  96        int no = 0;
  97
  98        d = debugfs_create_dir("setup_data", parent);
  99
 100        pa_data = boot_params.hdr.setup_data;
 101
 102        while (pa_data) {
 103                node = kmalloc(sizeof(*node), GFP_KERNEL);
 104                if (!node) {
 105                        error = -ENOMEM;
 106                        goto err_dir;
 107                }
 108
 109                data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
 110                if (!data) {
 111                        kfree(node);
 112                        error = -ENOMEM;
 113                        goto err_dir;
 114                }
 115
 116                if (data->type == SETUP_INDIRECT &&
 117                    ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
 118                        node->paddr = ((struct setup_indirect *)data->data)->addr;
 119                        node->type  = ((struct setup_indirect *)data->data)->type;
 120                        node->len   = ((struct setup_indirect *)data->data)->len;
 121                } else {
 122                        node->paddr = pa_data;
 123                        node->type  = data->type;
 124                        node->len   = data->len;
 125                }
 126
 127                create_setup_data_node(d, no, node);
 128                pa_data = data->next;
 129
 130                memunmap(data);
 131                no++;
 132        }
 133
 134        return 0;
 135
 136err_dir:
 137        debugfs_remove_recursive(d);
 138        return error;
 139}
 140
 141static struct debugfs_blob_wrapper boot_params_blob = {
 142        .data           = &boot_params,
 143        .size           = sizeof(boot_params),
 144};
 145
 146static int __init boot_params_kdebugfs_init(void)
 147{
 148        struct dentry *dbp;
 149        int error;
 150
 151        dbp = debugfs_create_dir("boot_params", arch_debugfs_dir);
 152
 153        debugfs_create_x16("version", S_IRUGO, dbp, &boot_params.hdr.version);
 154        debugfs_create_blob("data", S_IRUGO, dbp, &boot_params_blob);
 155
 156        error = create_setup_data_nodes(dbp);
 157        if (error)
 158                debugfs_remove_recursive(dbp);
 159
 160        return error;
 161}
 162#endif /* CONFIG_DEBUG_BOOT_PARAMS */
 163
 164static int __init arch_kdebugfs_init(void)
 165{
 166        int error = 0;
 167
 168        arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 169
 170#ifdef CONFIG_DEBUG_BOOT_PARAMS
 171        error = boot_params_kdebugfs_init();
 172#endif
 173
 174        return error;
 175}
 176arch_initcall(arch_kdebugfs_init);
 177