arch/x86/kernel/kdebugfs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Architecture specific debugfs files
   4  *
   5  * Copyright (C) 2007, Intel Corp.
   6  *      Huang Ying <ying.huang@intel.com>
   7  */
   8 #include <linux/debugfs.h>
   9 #include <linux/uaccess.h>
  10 #include <linux/export.h>
  11 #include <linux/slab.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         void *p;
  36         u64 pa;
  37
  38         if (pos < 0)
  39                 return -EINVAL;
  40
  41         if (pos >= node->len)
  42                 return 0;
  43
  44         if (count > node->len - pos)
  45                 count = node->len - pos;
  46
  47         pa = node->paddr + pos;
  48
  49         /* Is it direct data or invalid indirect one? */
  50         if (!(node->type & SETUP_INDIRECT) || node->type == SETUP_INDIRECT)
  51                 pa += sizeof(struct setup_data);
  52
  53         p = memremap(pa, count, MEMREMAP_WB);
  54         if (!p)
  55                 return -ENOMEM;
  56
  57         remain = copy_to_user(user_buf, p, count);
  58
  59         memunmap(p);
  60
  61         if (remain)
  62                 return -EFAULT;
  63
  64         *ppos = pos + count;
  65
  66         return count;
  67 }
  68
  69 static const struct file_operations fops_setup_data = {
  70         .read           = setup_data_read,
  71         .open           = simple_open,
  72         .llseek         = default_llseek,
  73 };
  74
  75 static void __init
  76 create_setup_data_node(struct dentry *parent, int no,
  77                        struct setup_data_node *node)
  78 {
  79         struct dentry *d;
  80         char buf[16];
  81
  82         sprintf(buf, "%d", no);
  83         d = debugfs_create_dir(buf, parent);
  84
  85         debugfs_create_x32("type", S_IRUGO, d, &node->type);
  86         debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
  87 }
  88
  89 static int __init create_setup_data_nodes(struct dentry *parent)
  90 {
  91         struct setup_indirect *indirect;
  92         struct setup_data_node *node;
  93         struct setup_data *data;
  94         u64 pa_data, pa_next;
  95         struct dentry *d;
  96         int error;
  97         u32 len;
  98         int no = 0;
  99
 100         d = debugfs_create_dir("setup_data", parent);
 101
 102         pa_data = boot_params.hdr.setup_data;
 103
 104         while (pa_data) {
 105                 node = kmalloc(sizeof(*node), GFP_KERNEL);
 106                 if (!node) {
 107                         error = -ENOMEM;
 108                         goto err_dir;
 109                 }
 110
 111                 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
 112                 if (!data) {
 113                         kfree(node);
 114                         error = -ENOMEM;
 115                         goto err_dir;
 116                 }
 117                 pa_next = data->next;
 118
 119                 if (data->type == SETUP_INDIRECT) {
 120                         len = sizeof(*data) + data->len;
 121                         memunmap(data);
 122                         data = memremap(pa_data, len, MEMREMAP_WB);
 123                         if (!data) {
 124                                 kfree(node);
 125                                 error = -ENOMEM;
 126                                 goto err_dir;
 127                         }
 128
 129                         indirect = (struct setup_indirect *)data->data;
 130
 131                         if (indirect->type != SETUP_INDIRECT) {
 132                                 node->paddr = indirect->addr;
 133                                 node->type  = indirect->type;
 134                                 node->len   = indirect->len;
 135                         } else {
 136                                 node->paddr = pa_data;
 137                                 node->type  = data->type;
 138                                 node->len   = data->len;
 139                         }
 140                 } else {
 141                         node->paddr = pa_data;
 142                         node->type  = data->type;
 143                         node->len   = data->len;
 144                 }
 145
 146                 create_setup_data_node(d, no, node);
 147                 pa_data = pa_next;
 148
 149                 memunmap(data);
 150                 no++;
 151         }
 152
 153         return 0;
 154
 155 err_dir:
 156         debugfs_remove_recursive(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;
 168         int error;
 169
 170         dbp = debugfs_create_dir("boot_params", arch_debugfs_dir);
 171
 172         debugfs_create_x16("version", S_IRUGO, dbp, &boot_params.hdr.version);
 173         debugfs_create_blob("data", S_IRUGO, dbp, &boot_params_blob);
 174
 175         error = create_setup_data_nodes(dbp);
 176         if (error)
 177                 debugfs_remove_recursive(dbp);
 178
 179         return error;
 180 }
 181 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
 182
 183 static int __init arch_kdebugfs_init(void)
 184 {
 185         int error = 0;
 186
 187         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 188
 189 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 190         error = boot_params_kdebugfs_init();
 191 #endif
 192
 193         return error;
 194 }
 195 arch_initcall(arch_kdebugfs_init);