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 };
  82
  83 static int __init
  84 create_setup_data_node(struct dentry *parent, int no,
  85                        struct setup_data_node *node)
  86 {
  87         struct dentry *d, *type, *data;
  88         char buf[16];
  89
  90         sprintf(buf, "%d", no);
  91         d = debugfs_create_dir(buf, parent);
  92         if (!d)
  93                 return -ENOMEM;
  94
  95         type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
  96         if (!type)
  97                 goto err_dir;
  98
  99         data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
 100         if (!data)
 101                 goto err_type;
 102
 103         return 0;
 104
 105 err_type:
 106         debugfs_remove(type);
 107 err_dir:
 108         debugfs_remove(d);
 109         return -ENOMEM;
 110 }
 111
 112 static int __init create_setup_data_nodes(struct dentry *parent)
 113 {
 114         struct setup_data_node *node;
 115         struct setup_data *data;
 116         int error = -ENOMEM;
 117         struct dentry *d;
 118         struct page *pg;
 119         u64 pa_data;
 120         int no = 0;
 121
 122         d = debugfs_create_dir("setup_data", parent);
 123         if (!d)
 124                 return -ENOMEM;
 125
 126         pa_data = boot_params.hdr.setup_data;
 127
 128         while (pa_data) {
 129                 node = kmalloc(sizeof(*node), GFP_KERNEL);
 130                 if (!node)
 131                         goto err_dir;
 132
 133                 pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
 134                 if (PageHighMem(pg)) {
 135                         data = ioremap_cache(pa_data, sizeof(*data));
 136                         if (!data) {
 137                                 kfree(node);
 138                                 error = -ENXIO;
 139                                 goto err_dir;
 140                         }
 141                 } else
 142                         data = __va(pa_data);
 143
 144                 node->paddr = pa_data;
 145                 node->type = data->type;
 146                 node->len = data->len;
 147                 error = create_setup_data_node(d, no, node);
 148                 pa_data = data->next;
 149
 150                 if (PageHighMem(pg))
 151                         iounmap(data);
 152                 if (error)
 153                         goto err_dir;
 154                 no++;
 155         }
 156
 157         return 0;
 158
 159 err_dir:
 160         debugfs_remove(d);
 161         return error;
 162 }
 163
 164 static struct debugfs_blob_wrapper boot_params_blob = {
 165         .data           = &boot_params,
 166         .size           = sizeof(boot_params),
 167 };
 168
 169 static int __init boot_params_kdebugfs_init(void)
 170 {
 171         struct dentry *dbp, *version, *data;
 172         int error = -ENOMEM;
 173
 174         dbp = debugfs_create_dir("boot_params", NULL);
 175         if (!dbp)
 176                 return -ENOMEM;
 177
 178         version = debugfs_create_x16("version", S_IRUGO, dbp,
 179                                      &boot_params.hdr.version);
 180         if (!version)
 181                 goto err_dir;
 182
 183         data = debugfs_create_blob("data", S_IRUGO, dbp,
 184                                    &boot_params_blob);
 185         if (!data)
 186                 goto err_version;
 187
 188         error = create_setup_data_nodes(dbp);
 189         if (error)
 190                 goto err_data;
 191
 192         return 0;
 193
 194 err_data:
 195         debugfs_remove(data);
 196 err_version:
 197         debugfs_remove(version);
 198 err_dir:
 199         debugfs_remove(dbp);
 200         return error;
 201 }
 202 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
 203
 204 static int __init arch_kdebugfs_init(void)
 205 {
 206         int error = 0;
 207
 208         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 209         if (!arch_debugfs_dir)
 210                 return -ENOMEM;
 211
 212 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 213         error = boot_params_kdebugfs_init();
 214 #endif
 215
 216         return error;
 217 }
 218 arch_initcall(arch_kdebugfs_init);