2 * custom_method.c - debugfs interface for customizing ACPI control method
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 <linux/acpi.h>
14 #define _COMPONENT ACPI_SYSTEM_COMPONENT
15 ACPI_MODULE_NAME("custom_method");
16 MODULE_LICENSE("GPL");
18 static struct dentry *cm_dentry;
20 /* /sys/kernel/debug/acpi/custom_method */
22 static ssize_t cm_write(struct file *file, const char __user * user_buf,
23 size_t count, loff_t *ppos)
27 static u32 uncopied_bytes;
29 struct acpi_table_header table;
33 /* parse the table header to get the table length */
34 if (count <= sizeof(struct acpi_table_header))
36 if (copy_from_user(&table, user_buf,
37 sizeof(struct acpi_table_header)))
39 uncopied_bytes = max_size = table.length;
40 /* make sure the buf is not allocated */
42 buf = kzalloc(max_size, GFP_KERNEL);
50 if ((*ppos > max_size) ||
51 (*ppos + count > max_size) ||
52 (*ppos + count < count) ||
53 (count > uncopied_bytes)) {
59 if (copy_from_user(buf + (*ppos), user_buf, count)) {
65 uncopied_bytes -= count;
68 if (!uncopied_bytes) {
69 status = acpi_install_method(buf);
72 if (ACPI_FAILURE(status))
74 add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
80 static const struct file_operations cm_fops = {
82 .llseek = default_llseek,
85 static int __init acpi_custom_method_init(void)
87 if (acpi_debugfs_dir == NULL)
90 cm_dentry = debugfs_create_file("custom_method", S_IWUSR,
91 acpi_debugfs_dir, NULL, &cm_fops);
92 if (cm_dentry == NULL)
98 static void __exit acpi_custom_method_exit(void)
101 debugfs_remove(cm_dentry);
104 module_init(acpi_custom_method_init);
105 module_exit(acpi_custom_method_exit);