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/init.h>
  13 #include <linux/stat.h>
  14 #include <linux/io.h>
  15 #include <linux/mm.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 setup_data_read(struct file *file, char __user *user_buf,
  30                                size_t count, loff_t *ppos)
  31 {
  32         struct setup_data_node *node = file->private_data;
  33         unsigned long remain;
  34         loff_t pos = *ppos;
  35         struct page *pg;
  36         void *p;
  37         u64 pa;
  38
  39         if (pos < 0)
  40                 return -EINVAL;
  41
  42         if (pos >= node->len)
  43                 return 0;
  44
  45         if (count > node->len - pos)
  46                 count = node->len - pos;
  47
  48         pa = node->paddr + sizeof(struct setup_data) + pos;
  49         pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
  50         if (PageHighMem(pg)) {
  51                 p = ioremap_cache(pa, count);
  52                 if (!p)
  53                         return -ENXIO;
  54         } else
  55                 p = __va(pa);
  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
  74         return 0;
  75 }
  76
  77 static const struct file_operations fops_setup_data = {
  78         .read           = setup_data_read,
  79         .open           = setup_data_open,
  80 };
  81
  82 static int __init
  83 create_setup_data_node(struct dentry *parent, int no,
  84                        struct setup_data_node *node)
  85 {
  86         struct dentry *d, *type, *data;
  87         char buf[16];
  88
  89         sprintf(buf, "%d", no);
  90         d = debugfs_create_dir(buf, parent);
  91         if (!d)
  92                 return -ENOMEM;
  93
  94         type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
  95         if (!type)
  96                 goto err_dir;
  97
  98         data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
  99         if (!data)
 100                 goto err_type;
 101
 102         return 0;
 103
 104 err_type:
 105         debugfs_remove(type);
 106 err_dir:
 107         debugfs_remove(d);
 108         return -ENOMEM;
 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 = -ENOMEM;
 116         struct dentry *d;
 117         struct page *pg;
 118         u64 pa_data;
 119         int no = 0;
 120
 121         d = debugfs_create_dir("setup_data", parent);
 122         if (!d)
 123                 return -ENOMEM;
 124
 125         pa_data = boot_params.hdr.setup_data;
 126
 127         while (pa_data) {
 128                 node = kmalloc(sizeof(*node), GFP_KERNEL);
 129                 if (!node)
 130                         goto err_dir;
 131
 132                 pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
 133                 if (PageHighMem(pg)) {
 134                         data = ioremap_cache(pa_data, sizeof(*data));
 135                         if (!data) {
 136                                 kfree(node);
 137                                 error = -ENXIO;
 138                                 goto err_dir;
 139                         }
 140                 } else
 141                         data = __va(pa_data);
 142
 143                 node->paddr = pa_data;
 144                 node->type = data->type;
 145                 node->len = data->len;
 146                 error = create_setup_data_node(d, no, node);
 147                 pa_data = data->next;
 148
 149                 if (PageHighMem(pg))
 150                         iounmap(data);
 151                 if (error)
 152                         goto err_dir;
 153                 no++;
 154         }
 155
 156         return 0;
 157
 158 err_dir:
 159         debugfs_remove(d);
 160         return error;
 161 }
 162
 163 static struct debugfs_blob_wrapper boot_params_blob = {
 164         .data           = &boot_params,
 165         .size           = sizeof(boot_params),
 166 };
 167
 168 static int __init boot_params_kdebugfs_init(void)
 169 {
 170         struct dentry *dbp, *version, *data;
 171         int error = -ENOMEM;
 172
 173         dbp = debugfs_create_dir("boot_params", NULL);
 174         if (!dbp)
 175                 return -ENOMEM;
 176
 177         version = debugfs_create_x16("version", S_IRUGO, dbp,
 178                                      &boot_params.hdr.version);
 179         if (!version)
 180                 goto err_dir;
 181
 182         data = debugfs_create_blob("data", S_IRUGO, dbp,
 183                                    &boot_params_blob);
 184         if (!data)
 185                 goto err_version;
 186
 187         error = create_setup_data_nodes(dbp);
 188         if (error)
 189                 goto err_data;
 190
 191         return 0;
 192
 193 err_data:
 194         debugfs_remove(data);
 195 err_version:
 196         debugfs_remove(version);
 197 err_dir:
 198         debugfs_remove(dbp);
 199         return error;
 200 }
 201 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
 202
 203 static int __init arch_kdebugfs_init(void)
 204 {
 205         int error = 0;
 206
 207         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 208         if (!arch_debugfs_dir)
 209                 return -ENOMEM;
 210
 211 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 212         error = boot_params_kdebugfs_init();
 213 #endif
 214
 215         return error;
 216 }
 217 arch_initcall(arch_kdebugfs_init);