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
  19 struct dentry *arch_debugfs_dir;
  20 EXPORT_SYMBOL(arch_debugfs_dir);
  21
  22 #ifdef CONFIG_DEBUG_BOOT_PARAMS
  23 struct setup_data_node {
  24         u64 paddr;
  25         u32 type;
  26         u32 len;
  27 };
  28
  29 static 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
  64 static const struct file_operations fops_setup_data = {
  65         .read           = setup_data_read,
  66         .open           = simple_open,
  67         .llseek         = default_llseek,
  68 };
  69
  70 static int __init
  71 create_setup_data_node(struct dentry *parent, int no,
  72                        struct setup_data_node *node)
  73 {
  74         struct dentry *d, *type, *data;
  75         char buf[16];
  76
  77         sprintf(buf, "%d", no);
  78         d = debugfs_create_dir(buf, parent);
  79         if (!d)
  80                 return -ENOMEM;
  81
  82         type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
  83         if (!type)
  84                 goto err_dir;
  85
  86         data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
  87         if (!data)
  88                 goto err_type;
  89
  90         return 0;
  91
  92 err_type:
  93         debugfs_remove(type);
  94 err_dir:
  95         debugfs_remove(d);
  96         return -ENOMEM;
  97 }
  98
  99 static int __init create_setup_data_nodes(struct dentry *parent)
 100 {
 101         struct setup_data_node *node;
 102         struct setup_data *data;
 103         int error;
 104         struct dentry *d;
 105         u64 pa_data;
 106         int no = 0;
 107
 108         d = debugfs_create_dir("setup_data", parent);
 109         if (!d)
 110                 return -ENOMEM;
 111
 112         pa_data = boot_params.hdr.setup_data;
 113
 114         while (pa_data) {
 115                 node = kmalloc(sizeof(*node), GFP_KERNEL);
 116                 if (!node) {
 117                         error = -ENOMEM;
 118                         goto err_dir;
 119                 }
 120
 121                 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
 122                 if (!data) {
 123                         kfree(node);
 124                         error = -ENOMEM;
 125                         goto err_dir;
 126                 }
 127
 128                 node->paddr = pa_data;
 129                 node->type = data->type;
 130                 node->len = data->len;
 131                 error = create_setup_data_node(d, no, node);
 132                 pa_data = data->next;
 133
 134                 memunmap(data);
 135                 if (error)
 136                         goto err_dir;
 137                 no++;
 138         }
 139
 140         return 0;
 141
 142 err_dir:
 143         debugfs_remove(d);
 144         return error;
 145 }
 146
 147 static struct debugfs_blob_wrapper boot_params_blob = {
 148         .data           = &boot_params,
 149         .size           = sizeof(boot_params),
 150 };
 151
 152 static int __init boot_params_kdebugfs_init(void)
 153 {
 154         struct dentry *dbp, *version, *data;
 155         int error = -ENOMEM;
 156
 157         dbp = debugfs_create_dir("boot_params", arch_debugfs_dir);
 158         if (!dbp)
 159                 return -ENOMEM;
 160
 161         version = debugfs_create_x16("version", S_IRUGO, dbp,
 162                                      &boot_params.hdr.version);
 163         if (!version)
 164                 goto err_dir;
 165
 166         data = debugfs_create_blob("data", S_IRUGO, dbp,
 167                                    &boot_params_blob);
 168         if (!data)
 169                 goto err_version;
 170
 171         error = create_setup_data_nodes(dbp);
 172         if (error)
 173                 goto err_data;
 174
 175         return 0;
 176
 177 err_data:
 178         debugfs_remove(data);
 179 err_version:
 180         debugfs_remove(version);
 181 err_dir:
 182         debugfs_remove(dbp);
 183         return error;
 184 }
 185 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
 186
 187 static int __init arch_kdebugfs_init(void)
 188 {
 189         int error = 0;
 190
 191         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 192         if (!arch_debugfs_dir)
 193                 return -ENOMEM;
 194
 195 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 196         error = boot_params_kdebugfs_init();
 197 #endif
 198
 199         return error;
 200 }
 201 arch_initcall(arch_kdebugfs_init);