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 13ACPI_MODULE_NAME("debugfs"); 14 15 16/* /sys/modules/acpi/parameters/aml_debug_output */ 17 18module_param_named(aml_debug_output, acpi_gbl_enable_aml_debug_object, 19 bool, 0644); 20MODULE_PARM_DESC(aml_debug_output, 21 "To enable/disable the ACPI Debug Object output."); 22 23/* /sys/kernel/debug/acpi/custom_method */ 24 25static 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 int uncopied_bytes; 30 struct acpi_table_header table; 31 acpi_status status; 32 33 if (!(*ppos)) { 34 /* parse the table header to get the table length */ 35 if (count <= sizeof(struct acpi_table_header)) 36 return -EINVAL; 37 if (copy_from_user(&table, user_buf, 38 sizeof(struct acpi_table_header))) 39 return -EFAULT; 40 uncopied_bytes = table.length; 41 buf = kzalloc(uncopied_bytes, GFP_KERNEL); 42 if (!buf) 43 return -ENOMEM; 44 } 45 46 if (uncopied_bytes < count) { 47 kfree(buf); 48 return -EINVAL; 49 } 50 51 if (copy_from_user(buf + (*ppos), user_buf, count)) { 52 kfree(buf); 53 return -EFAULT; 54 } 55 56 uncopied_bytes -= count; 57 *ppos += count; 58 59 if (!uncopied_bytes) { 60 status = acpi_install_method(buf); 61 kfree(buf); 62 if (ACPI_FAILURE(status)) 63 return -EINVAL; 64 add_taint(TAINT_OVERRIDDEN_ACPI_TABLE); 65 } 66 67 return count; 68} 69 70static const struct file_operations cm_fops = { 71 .write = cm_write, 72}; 73 74int __init acpi_debugfs_init(void) 75{ 76 struct dentry *acpi_dir, *cm_dentry; 77 78 acpi_dir = debugfs_create_dir("acpi", NULL); 79 if (!acpi_dir) 80 goto err; 81 82 cm_dentry = debugfs_create_file("custom_method", S_IWUSR, 83 acpi_dir, NULL, &cm_fops); 84 if (!cm_dentry) 85 goto err; 86 87 return 0; 88 89err: 90 if (acpi_dir) 91 debugfs_remove(acpi_dir); 92 return -EINVAL; 93} 94