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/module.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         struct page *pg;
  37         void *p;
  38         u64 pa;
  39
  40         if (pos < 0)
  41                 return -EINVAL;
  42
  43         if (pos >= node->len)
  44                 return 0;
  45
  46         if (count > node->len - pos)
  47                 count = node->len - pos;
  48
  49         pa = node->paddr + sizeof(struct setup_data) + pos;
  50         pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
  51         if (PageHighMem(pg)) {
  52                 p = ioremap_cache(pa, count);
  53                 if (!p)
  54                         return -ENXIO;
  55         } else
  56                 p = __va(pa);
  57
  58         remain = copy_to_user(user_buf, p, count);
  59
  60         if (PageHighMem(pg))
  61                 iounmap(p);
  62
  63         if (remain)
  64                 return -EFAULT;
  65
  66         *ppos = pos + count;
  67
  68         return count;
  69 }
  70
  71 static int setup_data_open(struct inode *inode, struct file *file)
  72 {
  73         file->private_data = inode->i_private;
  74
  75         return 0;
  76 }
  77
  78 static const struct file_operations fops_setup_data = {
  79         .read           = setup_data_read,
  80         .open           = setup_data_open,
  81         .llseek         = default_llseek,
  82 };
  83
  84 static int __init
  85 create_setup_data_node(struct dentry *parent, int no,
  86                        struct setup_data_node *node)
  87 {
  88         struct dentry *d, *type, *data;
  89         char buf[16];
  90
  91         sprintf(buf, "%d", no);
  92         d = debugfs_create_dir(buf, parent);
  93         if (!d)
  94                 return -ENOMEM;
  95
  96         type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
  97         if (!type)
  98                 goto err_dir;
  99
 100         data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
 101         if (!data)
 102                 goto err_type;
 103
 104         return 0;
 105
 106 err_type:
 107         debugfs_remove(type);
 108 err_dir:
 109         debugfs_remove(d);
 110         return -ENOMEM;
 111 }
 112
 113 static int __init create_setup_data_nodes(struct dentry *parent)
 114 {
 115         struct setup_data_node *node;
 116         struct setup_data *data;
 117         int error = -ENOMEM;
 118         struct dentry *d;
 119         struct page *pg;
 120         u64 pa_data;
 121         int no = 0;
 122
 123         d = debugfs_create_dir("setup_data", parent);
 124         if (!d)
 125                 return -ENOMEM;
 126
 127         pa_data = boot_params.hdr.setup_data;
 128
 129         while (pa_data) {
 130                 node = kmalloc(sizeof(*node), GFP_KERNEL);
 131                 if (!node)
 132                         goto err_dir;
 133
 134                 pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
 135                 if (PageHighMem(pg)) {
 136                         data = ioremap_cache(pa_data, sizeof(*data));
 137                         if (!data) {
 138                                 kfree(node);
 139                                 error = -ENXIO;
 140                                 goto err_dir;
 141                         }
 142                 } else
 143                         data = __va(pa_data);
 144
 145                 node->paddr = pa_data;
 146                 node->type = data->type;
 147                 node->len = data->len;
 148                 error = create_setup_data_node(d, no, node);
 149                 pa_data = data->next;
 150
 151                 if (PageHighMem(pg))
 152                         iounmap(data);
 153                 if (error)
 154                         goto err_dir;
 155                 no++;
 156         }
 157
 158         return 0;
 159
 160 err_dir:
 161         debugfs_remove(d);
 162         return error;
 163 }
 164
 165 static struct debugfs_blob_wrapper boot_params_blob = {
 166         .data           = &boot_params,
 167         .size           = sizeof(boot_params),
 168 };
 169
 170 static int __init boot_params_kdebugfs_init(void)
 171 {
 172         struct dentry *dbp, *version, *data;
 173         int error = -ENOMEM;
 174
 175         dbp = debugfs_create_dir("boot_params", NULL);
 176         if (!dbp)
 177                 return -ENOMEM;
 178
 179         version = debugfs_create_x16("version", S_IRUGO, dbp,
 180                                      &boot_params.hdr.version);
 181         if (!version)
 182                 goto err_dir;
 183
 184         data = debugfs_create_blob("data", S_IRUGO, dbp,
 185                                    &boot_params_blob);
 186         if (!data)
 187                 goto err_version;
 188
 189         error = create_setup_data_nodes(dbp);
 190         if (error)
 191                 goto err_data;
 192
 193         return 0;
 194
 195 err_data:
 196         debugfs_remove(data);
 197 err_version:
 198         debugfs_remove(version);
 199 err_dir:
 200         debugfs_remove(dbp);
 201         return error;
 202 }
 203 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
 204
 205 static int __init arch_kdebugfs_init(void)
 206 {
 207         int error = 0;
 208
 209         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 210         if (!arch_debugfs_dir)
 211                 return -ENOMEM;
 212
 213 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 214         error = boot_params_kdebugfs_init();
 215 #endif
 216
 217         return error;
 218 }
 219 arch_initcall(arch_kdebugfs_init);