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 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 = -ENOMEM;
 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                         goto err_dir;
 126
 127                 pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
 128                 if (PageHighMem(pg)) {
 129                         data = ioremap_cache(pa_data, sizeof(*data));
 130                         if (!data) {
 131                                 kfree(node);
 132                                 error = -ENXIO;
 133                                 goto err_dir;
 134                         }
 135                 } else
 136                         data = __va(pa_data);
 137
 138                 node->paddr = pa_data;
 139                 node->type = data->type;
 140                 node->len = data->len;
 141                 error = create_setup_data_node(d, no, node);
 142                 pa_data = data->next;
 143
 144                 if (PageHighMem(pg))
 145                         iounmap(data);
 146                 if (error)
 147                         goto err_dir;
 148                 no++;
 149         }
 150
 151         return 0;
 152
 153 err_dir:
 154         debugfs_remove(d);
 155         return error;
 156 }
 157
 158 static struct debugfs_blob_wrapper boot_params_blob = {
 159         .data           = &boot_params,
 160         .size           = sizeof(boot_params),
 161 };
 162
 163 static int __init boot_params_kdebugfs_init(void)
 164 {
 165         struct dentry *dbp, *version, *data;
 166         int error = -ENOMEM;
 167
 168         dbp = debugfs_create_dir("boot_params", NULL);
 169         if (!dbp)
 170                 return -ENOMEM;
 171
 172         version = debugfs_create_x16("version", S_IRUGO, dbp,
 173                                      &boot_params.hdr.version);
 174         if (!version)
 175                 goto err_dir;
 176
 177         data = debugfs_create_blob("data", S_IRUGO, dbp,
 178                                    &boot_params_blob);
 179         if (!data)
 180                 goto err_version;
 181
 182         error = create_setup_data_nodes(dbp);
 183         if (error)
 184                 goto err_data;
 185
 186         return 0;
 187
 188 err_data:
 189         debugfs_remove(data);
 190 err_version:
 191         debugfs_remove(version);
 192 err_dir:
 193         debugfs_remove(dbp);
 194         return error;
 195 }
 196 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
 197
 198 static int __init arch_kdebugfs_init(void)
 199 {
 200         int error = 0;
 201
 202         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 203         if (!arch_debugfs_dir)
 204                 return -ENOMEM;
 205
 206 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 207         error = boot_params_kdebugfs_init();
 208 #endif
 209
 210         return error;
 211 }
 212 arch_initcall(arch_kdebugfs_init);