root/arch/x86/kernel/kdebugfs.c

DEFINITIONS

1. setup_data_read
2. create_setup_data_node
3. create_setup_data_nodes
4. boot_params_kdebugfs_init
5. arch_kdebugfs_init

   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 + sizeof(struct setup_data) + pos;
  48         p = memremap(pa, count, MEMREMAP_WB);
  49         if (!p)
  50                 return -ENOMEM;
  51 
  52         remain = copy_to_user(user_buf, p, count);
  53 
  54         memunmap(p);
  55 
  56         if (remain)
  57                 return -EFAULT;
  58 
  59         *ppos = pos + count;
  60 
  61         return count;
  62 }
  63 
  64 static const struct file_operations fops_setup_data = {
  65         .read           = setup_data_read,
  66         .open           = simple_open,
  67         .llseek         = default_llseek,
  68 };
  69 
  70 static void __init
  71 create_setup_data_node(struct dentry *parent, int no,
  72                        struct setup_data_node *node)
  73 {
  74         struct dentry *d;
  75         char buf[16];
  76 
  77         sprintf(buf, "%d", no);
  78         d = debugfs_create_dir(buf, parent);
  79 
  80         debugfs_create_x32("type", S_IRUGO, d, &node->type);
  81         debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
  82 }
  83 
  84 static int __init create_setup_data_nodes(struct dentry *parent)
  85 {
  86         struct setup_data_node *node;
  87         struct setup_data *data;
  88         int error;
  89         struct dentry *d;
  90         u64 pa_data;
  91         int no = 0;
  92 
  93         d = debugfs_create_dir("setup_data", parent);
  94 
  95         pa_data = boot_params.hdr.setup_data;
  96 
  97         while (pa_data) {
  98                 node = kmalloc(sizeof(*node), GFP_KERNEL);
  99                 if (!node) {
 100                         error = -ENOMEM;
 101                         goto err_dir;
 102                 }
 103 
 104                 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
 105                 if (!data) {
 106                         kfree(node);
 107                         error = -ENOMEM;
 108                         goto err_dir;
 109                 }
 110 
 111                 node->paddr = pa_data;
 112                 node->type = data->type;
 113                 node->len = data->len;
 114                 create_setup_data_node(d, no, node);
 115                 pa_data = data->next;
 116 
 117                 memunmap(data);
 118                 no++;
 119         }
 120 
 121         return 0;
 122 
 123 err_dir:
 124         debugfs_remove_recursive(d);
 125         return error;
 126 }
 127 
 128 static struct debugfs_blob_wrapper boot_params_blob = {
 129         .data           = &boot_params,
 130         .size           = sizeof(boot_params),
 131 };
 132 
 133 static int __init boot_params_kdebugfs_init(void)
 134 {
 135         struct dentry *dbp;
 136         int error;
 137 
 138         dbp = debugfs_create_dir("boot_params", arch_debugfs_dir);
 139 
 140         debugfs_create_x16("version", S_IRUGO, dbp, &boot_params.hdr.version);
 141         debugfs_create_blob("data", S_IRUGO, dbp, &boot_params_blob);
 142 
 143         error = create_setup_data_nodes(dbp);
 144         if (error)
 145                 debugfs_remove_recursive(dbp);
 146 
 147         return error;
 148 }
 149 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
 150 
 151 static int __init arch_kdebugfs_init(void)
 152 {
 153         int error = 0;
 154 
 155         arch_debugfs_dir = debugfs_create_dir("x86", NULL);
 156 
 157 #ifdef CONFIG_DEBUG_BOOT_PARAMS
 158         error = boot_params_kdebugfs_init();
 159 #endif
 160 
 161         return error;
 162 }
 163 arch_initcall(arch_kdebugfs_init);