Revert "ARM: tegra: tegratab: dummy change"
[linux-2.6.git] / drivers / acpi / custom_method.c
1 /*
2  * debugfs.c - ACPI debugfs interface to userspace.
3  */
4
5 #include <linux/init.h>
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 #include <linux/uaccess.h>
9 #include <linux/debugfs.h>
10 #include <acpi/acpi_drivers.h>
11
12 #include "internal.h"
13
14 #define _COMPONENT              ACPI_SYSTEM_COMPONENT
15 ACPI_MODULE_NAME("custom_method");
16 MODULE_LICENSE("GPL");
17
18 static struct dentry *cm_dentry;
19
20 /* /sys/kernel/debug/acpi/custom_method */
21
22 static ssize_t cm_write(struct file *file, const char __user * user_buf,
23                         size_t count, loff_t *ppos)
24 {
25         static char *buf;
26         static u32 max_size;
27         static u32 uncopied_bytes;
28
29         struct acpi_table_header table;
30         acpi_status status;
31
32         if (!(*ppos)) {
33                 /* parse the table header to get the table length */
34                 if (count <= sizeof(struct acpi_table_header))
35                         return -EINVAL;
36                 if (copy_from_user(&table, user_buf,
37                                    sizeof(struct acpi_table_header)))
38                         return -EFAULT;
39                 uncopied_bytes = max_size = table.length;
40                 buf = kzalloc(max_size, GFP_KERNEL);
41                 if (!buf)
42                         return -ENOMEM;
43         }
44
45         if (buf == NULL)
46                 return -EINVAL;
47
48         if ((*ppos > max_size) ||
49             (*ppos + count > max_size) ||
50             (*ppos + count < count) ||
51             (count > uncopied_bytes))
52                 return -EINVAL;
53
54         if (copy_from_user(buf + (*ppos), user_buf, count)) {
55                 kfree(buf);
56                 buf = NULL;
57                 return -EFAULT;
58         }
59
60         uncopied_bytes -= count;
61         *ppos += count;
62
63         if (!uncopied_bytes) {
64                 status = acpi_install_method(buf);
65                 kfree(buf);
66                 buf = NULL;
67                 if (ACPI_FAILURE(status))
68                         return -EINVAL;
69                 add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
70         }
71
72         return count;
73 }
74
75 static const struct file_operations cm_fops = {
76         .write = cm_write,
77         .llseek = default_llseek,
78 };
79
80 static int __init acpi_custom_method_init(void)
81 {
82         if (acpi_debugfs_dir == NULL)
83                 return -ENOENT;
84
85         cm_dentry = debugfs_create_file("custom_method", S_IWUSR,
86                                         acpi_debugfs_dir, NULL, &cm_fops);
87         if (cm_dentry == NULL)
88                 return -ENODEV;
89
90         return 0;
91 }
92
93 static void __exit acpi_custom_method_exit(void)
94 {
95         if (cm_dentry)
96                 debugfs_remove(cm_dentry);
97  }
98
99 module_init(acpi_custom_method_init);
100 module_exit(acpi_custom_method_exit);