Merge branch 'for-davem' of ssh://master.kernel.org/pub/scm/linux/kernel/git/linville...
[linux-2.6.git] / drivers / acpi / debugfs.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 #define _COMPONENT              ACPI_SYSTEM_COMPONENT
13 ACPI_MODULE_NAME("debugfs");
14
15
16 /* /sys/modules/acpi/parameters/aml_debug_output */
17
18 module_param_named(aml_debug_output, acpi_gbl_enable_aml_debug_object,
19                    bool, 0644);
20 MODULE_PARM_DESC(aml_debug_output,
21                  "To enable/disable the ACPI Debug Object output.");
22
23 /* /sys/kernel/debug/acpi/custom_method */
24
25 static ssize_t cm_write(struct file *file, const char __user * user_buf,
26                         size_t count, loff_t *ppos)
27 {
28         static char *buf;
29         static u32 max_size;
30         static u32 uncopied_bytes;
31
32         struct acpi_table_header table;
33         acpi_status status;
34
35         if (!(*ppos)) {
36                 /* parse the table header to get the table length */
37                 if (count <= sizeof(struct acpi_table_header))
38                         return -EINVAL;
39                 if (copy_from_user(&table, user_buf,
40                                    sizeof(struct acpi_table_header)))
41                         return -EFAULT;
42                 uncopied_bytes = max_size = table.length;
43                 buf = kzalloc(max_size, GFP_KERNEL);
44                 if (!buf)
45                         return -ENOMEM;
46         }
47
48         if (buf == NULL)
49                 return -EINVAL;
50
51         if ((*ppos > max_size) ||
52             (*ppos + count > max_size) ||
53             (*ppos + count < count) ||
54             (count > uncopied_bytes))
55                 return -EINVAL;
56
57         if (copy_from_user(buf + (*ppos), user_buf, count)) {
58                 kfree(buf);
59                 buf = NULL;
60                 return -EFAULT;
61         }
62
63         uncopied_bytes -= count;
64         *ppos += count;
65
66         if (!uncopied_bytes) {
67                 status = acpi_install_method(buf);
68                 kfree(buf);
69                 buf = NULL;
70                 if (ACPI_FAILURE(status))
71                         return -EINVAL;
72                 add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
73         }
74
75         return count;
76 }
77
78 static const struct file_operations cm_fops = {
79         .write = cm_write,
80         .llseek = default_llseek,
81 };
82
83 int __init acpi_debugfs_init(void)
84 {
85         struct dentry *acpi_dir, *cm_dentry;
86
87         acpi_dir = debugfs_create_dir("acpi", NULL);
88         if (!acpi_dir)
89                 goto err;
90
91         cm_dentry = debugfs_create_file("custom_method", S_IWUSR,
92                                         acpi_dir, NULL, &cm_fops);
93         if (!cm_dentry)
94                 goto err;
95
96         return 0;
97
98 err:
99         if (acpi_dir)
100                 debugfs_remove(acpi_dir);
101         return -EINVAL;
102 }