arch/x86/kernel/kdebugfs.c

   1 /*
   2  * Architecture specific debugfs files
   3  *
   4  * Copyright (C) 2007, Intel Corp.
   5  *      Huang Ying <ying.huang@intel.com>
   6  *
   7  * This file is released under the GPLv2.
   8  */
   9 #include <linux/debugfs.h>
  10 #include <linux/uaccess.h>
  11 #include <linux/export.h>
  12 #include <linux/slab.h>
  13 #include <linux/init.h>
  14 #include <linux/stat.h>
  15 #include <linux/io.h>
  16 #include <linux/mm.h>
  17
  18 #include <asm/setup.h>
  19
  20 struct dentry *arch_debugfs_dir;
  21 EXPORT_SYMBOL(arch_debugfs_dir);
  22
  23 #ifdef CONFIG_DEBUG_BOOT_PARAMS
  24 struct setup_data_node {
  25         u64 paddr;
  26         u32 type;
  27         u32 len;
  28 };
  29
  30 static ssize_t setup_data_read(struct file *file, char __user *user_buf,
  31                                size_t count, loff_t *ppos)
  32 {
  33         struct setup_data_node *node = file->private_data;
  34         unsigned long remain;
  35         loff_t pos = *ppos;
  36         void *p;
  37         u64 pa;
  38
  39         if (pos < 0)
  40                 return -EINVAL;
  41
  42         if (pos >= node->len)
  43                 return 0;
  44
  45         if (count > node->len - pos)
  46                 count = node->len - pos;
  47
  48         pa = node->paddr + sizeof(struct setup_data) + pos;
  49         p = memremap(pa, count, MEMREMAP_WB);
  50         if (!p)
  51                 return -ENOMEM;
  52
  53         remain = copy_to_user(user_buf, p, count);
  54
  55         memunmap(p);
  56
  57         if (remain)
  58                 return -EFAULT;
  59
  60         *ppos = pos + count;
  61
  62         return count;
  63 }
  64
  65 static const struct file_operations fops_setup_data = {
  66         .read           = setup_data_read,
  67         .open           = simple_open,
  68         .llseek         = default_llseek,
  69 };
  70
  71 static int __init
  72 create_setup_data_node(struct dentry *parent, int no,
  73                        struct setup_data_node *node)
  74 {
  75         struct dentry *d, *type, *data;
  76         char buf[16];
  77
  78         sprintf(buf, "%d", no);
  79         d = debugfs_create_dir(buf, parent);
  80         if (!d)
  81                 return -ENOMEM;
  82
  83         type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
  84         if (!type)
  85                 goto err_dir;
  86
  87         data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
  88         if (!data)
  89                 goto err_type;
  90
  91         return 0;
  92
  93 err_type:
  94         debugfs_remove(type);
  95 err_dir:
  96         debugfs_remove(d);
  97         return -ENOMEM;
  98 }
  99
 100 static int __init create_setup_data_nodes(struct dentry *parent)
 101 {
 102         struct setup_data_node *node;
 103         struct setup_data *data;
 104         int error;
 105         struct dentry *d;
 106         u64 pa_data;
 107         int no = 0;
 108
 109         d = debugfs_create_dir("setup_data", parent);
 110         if (!d)
 111                 return -ENOMEM;
 112
 113         pa_data = boot_params.hdr.setup_data;
 114
 115         while (pa_data) {
 116                 node = kmalloc(sizeof(*node), GFP_KERNEL);
 117                 if (!node) {
 118                         error = -ENOMEM;
 119                         goto err_dir;
 120                 }
 121
 122                 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
 123                 if (!data) {
 124                         kfree(node);
 125                         error = -ENOMEM;
 126                         goto err_dir;
 127                 }
 128
 129                 node->paddr = pa_data;
 130                 node->type = data->type;
 131                 node->len = data->len;
 132                 error = create_setup_data_node(d, no, node);
 133                 pa_data = data->next;
 134
 135                 memunmap(data);
 136                 if (error)
 137                         goto err_dir;
 138                 no++;
 139         }
 140
 141         return 0;
 142
 143 err_dir:
 144         debugfs_remove(d);
 145         return error;
 146 }
 147
 148 static struct debugfs_blob_wrapper boot_params_blob = {
 149         .data           = &boot_params,
 150         .size           = sizeof(boot_params),
 151 };
 152
 153 static int __init boot_params_kdebugfs_init(void)
 154 {
 155         struct dentry *dbp, *version, *data;
 156         int error = -ENOMEM;
 157
 158         dbp = debugfs_create_dir("boot_params", arch_debugfs_dir);
 159         if (!dbp)
 160                 return -ENOMEM;
 161
 162         version = debugfs_create_x16("version", S_IRUGO, dbp,
 163                                      &boot_params.hdr.version);
 164         if (!version)
 165                 goto err_dir;
 166
 167         data = debugfs_create_blob("data", S_IRUGO, dbp,
 168                                    &boot_params_blob);
 169         if (!data)
 170                 goto err_version;
 171
 172         error = create_setup_data_nodes(dbp);
 173         if (error)
 174                 goto err_data;
 175
 176         return 0;
 177
 178 err_data:
 179         debugfs_remove(data);
 180 err_version:
 181         debugfs_remove(version);
 182 err_dir:
 183         debugfs_remove(dbp);
 184         return error;
 185 }
 186 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
 187
 188 static int __init arch_kdebugfs_init(void)
 189 {
 190         int error = 0;
 191
 192         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 193         if (!arch_debugfs_dir)
 194                 return -ENOMEM;
 195
 196 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 197         error = boot_params_kdebugfs_init();
 198 #endif
 199
 200         return error;
 201 }
 202 arch_initcall(arch_kdebugfs_init);