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