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/stat.h>
  12 #include <linux/init.h>
  13 #include <linux/io.h>
  14 #include <linux/mm.h>
  15 #include <linux/module.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
  30 setup_data_read(struct file *file, char __user *user_buf, size_t count,
  31                 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         if (pos >= node->len)
  43                 return 0;
  44
  45         if (count > node->len - pos)
  46                 count = node->len - pos;
  47         pa = node->paddr + sizeof(struct setup_data) + pos;
  48         pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
  49         if (PageHighMem(pg)) {
  50                 p = ioremap_cache(pa, count);
  51                 if (!p)
  52                         return -ENXIO;
  53         } else {
  54                 p = __va(pa);
  55         }
  56
  57         remain = copy_to_user(user_buf, p, count);
  58
  59         if (PageHighMem(pg))
  60                 iounmap(p);
  61
  62         if (remain)
  63                 return -EFAULT;
  64
  65         *ppos = pos + count;
  66
  67         return count;
  68 }
  69
  70 static int setup_data_open(struct inode *inode, struct file *file)
  71 {
  72         file->private_data = inode->i_private;
  73         return 0;
  74 }
  75
  76 static const struct file_operations fops_setup_data = {
  77         .read =         setup_data_read,
  78         .open =         setup_data_open,
  79 };
  80
  81 static int __init
  82 create_setup_data_node(struct dentry *parent, int no,
  83                        struct setup_data_node *node)
  84 {
  85         struct dentry *d, *type, *data;
  86         char buf[16];
  87         int error;
  88
  89         sprintf(buf, "%d", no);
  90         d = debugfs_create_dir(buf, parent);
  91         if (!d) {
  92                 error = -ENOMEM;
  93                 goto err_return;
  94         }
  95         type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
  96         if (!type) {
  97                 error = -ENOMEM;
  98                 goto err_dir;
  99         }
 100         data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
 101         if (!data) {
 102                 error = -ENOMEM;
 103                 goto err_type;
 104         }
 105         return 0;
 106
 107 err_type:
 108         debugfs_remove(type);
 109 err_dir:
 110         debugfs_remove(d);
 111 err_return:
 112         return error;
 113 }
 114
 115 static int __init create_setup_data_nodes(struct dentry *parent)
 116 {
 117         struct setup_data_node *node;
 118         struct setup_data *data;
 119         int error, no = 0;
 120         struct dentry *d;
 121         struct page *pg;
 122         u64 pa_data;
 123
 124         d = debugfs_create_dir("setup_data", parent);
 125         if (!d) {
 126                 error = -ENOMEM;
 127                 goto err_return;
 128         }
 129
 130         pa_data = boot_params.hdr.setup_data;
 131
 132         while (pa_data) {
 133                 node = kmalloc(sizeof(*node), GFP_KERNEL);
 134                 if (!node) {
 135                         error = -ENOMEM;
 136                         goto err_dir;
 137                 }
 138                 pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
 139                 if (PageHighMem(pg)) {
 140                         data = ioremap_cache(pa_data, sizeof(*data));
 141                         if (!data) {
 142                                 kfree(node);
 143                                 error = -ENXIO;
 144                                 goto err_dir;
 145                         }
 146                 } else {
 147                         data = __va(pa_data);
 148                 }
 149
 150                 node->paddr = pa_data;
 151                 node->type = data->type;
 152                 node->len = data->len;
 153                 error = create_setup_data_node(d, no, node);
 154                 pa_data = data->next;
 155
 156                 if (PageHighMem(pg))
 157                         iounmap(data);
 158                 if (error)
 159                         goto err_dir;
 160                 no++;
 161         }
 162         return 0;
 163
 164 err_dir:
 165         debugfs_remove(d);
 166 err_return:
 167         return error;
 168 }
 169
 170 static struct debugfs_blob_wrapper boot_params_blob = {
 171         .data           = &boot_params,
 172         .size           = sizeof(boot_params),
 173 };
 174
 175 static int __init boot_params_kdebugfs_init(void)
 176 {
 177         struct dentry *dbp, *version, *data;
 178         int error;
 179
 180         dbp = debugfs_create_dir("boot_params", NULL);
 181         if (!dbp) {
 182                 error = -ENOMEM;
 183                 goto err_return;
 184         }
 185         version = debugfs_create_x16("version", S_IRUGO, dbp,
 186                                      &boot_params.hdr.version);
 187         if (!version) {
 188                 error = -ENOMEM;
 189                 goto err_dir;
 190         }
 191         data = debugfs_create_blob("data", S_IRUGO, dbp,
 192                                    &boot_params_blob);
 193         if (!data) {
 194                 error = -ENOMEM;
 195                 goto err_version;
 196         }
 197         error = create_setup_data_nodes(dbp);
 198         if (error)
 199                 goto err_data;
 200         return 0;
 201
 202 err_data:
 203         debugfs_remove(data);
 204 err_version:
 205         debugfs_remove(version);
 206 err_dir:
 207         debugfs_remove(dbp);
 208 err_return:
 209         return error;
 210 }
 211 #endif
 212
 213 static int __init arch_kdebugfs_init(void)
 214 {
 215         int error = 0;
 216
 217         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 218         if (!arch_debugfs_dir)
 219                 return -ENOMEM;
 220
 221 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 222         error = boot_params_kdebugfs_init();
 223 #endif
 224
 225         return error;
 226 }
 227 arch_initcall(arch_kdebugfs_init);