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
  16 #include <asm/setup.h>
  17
  18 #ifdef CONFIG_DEBUG_BOOT_PARAMS
  19 struct setup_data_node {
  20         u64 paddr;
  21         u32 type;
  22         u32 len;
  23 };
  24
  25 static ssize_t
  26 setup_data_read(struct file *file, char __user *user_buf, size_t count,
  27                 loff_t *ppos)
  28 {
  29         struct setup_data_node *node = file->private_data;
  30         unsigned long remain;
  31         loff_t pos = *ppos;
  32         struct page *pg;
  33         void *p;
  34         u64 pa;
  35
  36         if (pos < 0)
  37                 return -EINVAL;
  38         if (pos >= node->len)
  39                 return 0;
  40
  41         if (count > node->len - pos)
  42                 count = node->len - pos;
  43         pa = node->paddr + sizeof(struct setup_data) + pos;
  44         pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
  45         if (PageHighMem(pg)) {
  46                 p = ioremap_cache(pa, count);
  47                 if (!p)
  48                         return -ENXIO;
  49         } else {
  50                 p = __va(pa);
  51         }
  52
  53         remain = copy_to_user(user_buf, p, count);
  54
  55         if (PageHighMem(pg))
  56                 iounmap(p);
  57
  58         if (remain)
  59                 return -EFAULT;
  60
  61         *ppos = pos + count;
  62
  63         return count;
  64 }
  65
  66 static int setup_data_open(struct inode *inode, struct file *file)
  67 {
  68         file->private_data = inode->i_private;
  69         return 0;
  70 }
  71
  72 static const struct file_operations fops_setup_data = {
  73         .read =         setup_data_read,
  74         .open =         setup_data_open,
  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         int error;
  84
  85         sprintf(buf, "%d", no);
  86         d = debugfs_create_dir(buf, parent);
  87         if (!d) {
  88                 error = -ENOMEM;
  89                 goto err_return;
  90         }
  91         type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
  92         if (!type) {
  93                 error = -ENOMEM;
  94                 goto err_dir;
  95         }
  96         data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
  97         if (!data) {
  98                 error = -ENOMEM;
  99                 goto err_type;
 100         }
 101         return 0;
 102
 103 err_type:
 104         debugfs_remove(type);
 105 err_dir:
 106         debugfs_remove(d);
 107 err_return:
 108         return error;
 109 }
 110
 111 static int __init create_setup_data_nodes(struct dentry *parent)
 112 {
 113         struct setup_data_node *node;
 114         struct setup_data *data;
 115         int error, no = 0;
 116         struct dentry *d;
 117         struct page *pg;
 118         u64 pa_data;
 119
 120         d = debugfs_create_dir("setup_data", parent);
 121         if (!d) {
 122                 error = -ENOMEM;
 123                 goto err_return;
 124         }
 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                         error = -ENOMEM;
 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                                 error = -ENXIO;
 139                                 goto err_dir;
 140                         }
 141                 } else {
 142                         data = __va(pa_data);
 143                 }
 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         return 0;
 158
 159 err_dir:
 160         debugfs_remove(d);
 161 err_return:
 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;
 174
 175         dbp = debugfs_create_dir("boot_params", NULL);
 176         if (!dbp) {
 177                 error = -ENOMEM;
 178                 goto err_return;
 179         }
 180         version = debugfs_create_x16("version", S_IRUGO, dbp,
 181                                      &boot_params.hdr.version);
 182         if (!version) {
 183                 error = -ENOMEM;
 184                 goto err_dir;
 185         }
 186         data = debugfs_create_blob("data", S_IRUGO, dbp,
 187                                    &boot_params_blob);
 188         if (!data) {
 189                 error = -ENOMEM;
 190                 goto err_version;
 191         }
 192         error = create_setup_data_nodes(dbp);
 193         if (error)
 194                 goto err_data;
 195         return 0;
 196
 197 err_data:
 198         debugfs_remove(data);
 199 err_version:
 200         debugfs_remove(version);
 201 err_dir:
 202         debugfs_remove(dbp);
 203 err_return:
 204         return error;
 205 }
 206 #endif
 207
 208 static int __init arch_kdebugfs_init(void)
 209 {
 210         int error = 0;
 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);