1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Functions corresponding to SET methods under BIOS attributes interface GUID for use
4 * with dell-wmi-sysman
5 *
6 * Copyright (c) 2020 Dell Inc.
7 */
8
9 #include <linux/wmi.h>
10 #include "dell-wmi-sysman.h"
11
12 #define SETDEFAULTVALUES_METHOD_ID 0x02
13 #define SETBIOSDEFAULTS_METHOD_ID 0x03
14 #define SETATTRIBUTE_METHOD_ID 0x04
15
call_biosattributes_interface(struct wmi_device * wdev,char * in_args,size_t size,int method_id)16 static int call_biosattributes_interface(struct wmi_device *wdev, char *in_args, size_t size,
17 int method_id)
18 {
19 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
20 struct acpi_buffer input;
21 union acpi_object *obj;
22 acpi_status status;
23 int ret = -EIO;
24
25 input.length = (acpi_size) size;
26 input.pointer = in_args;
27 status = wmidev_evaluate_method(wdev, 0, method_id, &input, &output);
28 if (ACPI_FAILURE(status))
29 return -EIO;
30 obj = (union acpi_object *)output.pointer;
31 if (obj->type == ACPI_TYPE_INTEGER)
32 ret = obj->integer.value;
33
34 if (wmi_priv.pending_changes == 0) {
35 wmi_priv.pending_changes = 1;
36 /* let userland know it may need to check reboot pending again */
37 kobject_uevent(&wmi_priv.class_dev->kobj, KOBJ_CHANGE);
38 }
39 kfree(output.pointer);
40 return map_wmi_error(ret);
41 }
42
43 /**
44 * set_attribute() - Update an attribute value
45 * @a_name: The attribute name
46 * @a_value: The attribute value
47 *
48 * Sets an attribute to new value
49 */
set_attribute(const char * a_name,const char * a_value)50 int set_attribute(const char *a_name, const char *a_value)
51 {
52 size_t security_area_size, buffer_size;
53 size_t a_name_size, a_value_size;
54 char *buffer = NULL, *start;
55 int ret;
56
57 mutex_lock(&wmi_priv.mutex);
58 if (!wmi_priv.bios_attr_wdev) {
59 ret = -ENODEV;
60 goto out;
61 }
62
63 /* build/calculate buffer */
64 security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
65 a_name_size = calculate_string_buffer(a_name);
66 a_value_size = calculate_string_buffer(a_value);
67 buffer_size = security_area_size + a_name_size + a_value_size;
68 buffer = kzalloc(buffer_size, GFP_KERNEL);
69 if (!buffer) {
70 ret = -ENOMEM;
71 goto out;
72 }
73
74 /* build security area */
75 populate_security_buffer(buffer, wmi_priv.current_admin_password);
76
77 /* build variables to set */
78 start = buffer + security_area_size;
79 ret = populate_string_buffer(start, a_name_size, a_name);
80 if (ret < 0)
81 goto out;
82 start += ret;
83 ret = populate_string_buffer(start, a_value_size, a_value);
84 if (ret < 0)
85 goto out;
86
87 print_hex_dump_bytes("set attribute data: ", DUMP_PREFIX_NONE, buffer, buffer_size);
88 ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev,
89 buffer, buffer_size,
90 SETATTRIBUTE_METHOD_ID);
91 if (ret == -EOPNOTSUPP)
92 dev_err(&wmi_priv.bios_attr_wdev->dev, "admin password must be configured\n");
93 else if (ret == -EACCES)
94 dev_err(&wmi_priv.bios_attr_wdev->dev, "invalid password\n");
95
96 out:
97 kfree(buffer);
98 mutex_unlock(&wmi_priv.mutex);
99 return ret;
100 }
101
102 /**
103 * set_bios_defaults() - Resets BIOS defaults
104 * @deftype: the type of BIOS value reset to issue.
105 *
106 * Resets BIOS defaults
107 */
set_bios_defaults(u8 deftype)108 int set_bios_defaults(u8 deftype)
109 {
110 size_t security_area_size, buffer_size;
111 size_t integer_area_size = sizeof(u8);
112 char *buffer = NULL;
113 u8 *defaultType;
114 int ret;
115
116 mutex_lock(&wmi_priv.mutex);
117 if (!wmi_priv.bios_attr_wdev) {
118 ret = -ENODEV;
119 goto out;
120 }
121
122 security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
123 buffer_size = security_area_size + integer_area_size;
124 buffer = kzalloc(buffer_size, GFP_KERNEL);
125 if (!buffer) {
126 ret = -ENOMEM;
127 goto out;
128 }
129
130 /* build security area */
131 populate_security_buffer(buffer, wmi_priv.current_admin_password);
132
133 defaultType = buffer + security_area_size;
134 *defaultType = deftype;
135
136 ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev, buffer, buffer_size,
137 SETBIOSDEFAULTS_METHOD_ID);
138 if (ret)
139 dev_err(&wmi_priv.bios_attr_wdev->dev, "reset BIOS defaults failed: %d\n", ret);
140
141 kfree(buffer);
142 out:
143 mutex_unlock(&wmi_priv.mutex);
144 return ret;
145 }
146
bios_attr_set_interface_probe(struct wmi_device * wdev,const void * context)147 static int bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
148 {
149 mutex_lock(&wmi_priv.mutex);
150 wmi_priv.bios_attr_wdev = wdev;
151 mutex_unlock(&wmi_priv.mutex);
152 return 0;
153 }
154
bios_attr_set_interface_remove(struct wmi_device * wdev)155 static void bios_attr_set_interface_remove(struct wmi_device *wdev)
156 {
157 mutex_lock(&wmi_priv.mutex);
158 wmi_priv.bios_attr_wdev = NULL;
159 mutex_unlock(&wmi_priv.mutex);
160 }
161
162 static const struct wmi_device_id bios_attr_set_interface_id_table[] = {
163 { .guid_string = DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID },
164 { },
165 };
166 static struct wmi_driver bios_attr_set_interface_driver = {
167 .driver = {
168 .name = DRIVER_NAME
169 },
170 .probe = bios_attr_set_interface_probe,
171 .remove = bios_attr_set_interface_remove,
172 .id_table = bios_attr_set_interface_id_table,
173 };
174
init_bios_attr_set_interface(void)175 int init_bios_attr_set_interface(void)
176 {
177 return wmi_driver_register(&bios_attr_set_interface_driver);
178 }
179
exit_bios_attr_set_interface(void)180 void exit_bios_attr_set_interface(void)
181 {
182 wmi_driver_unregister(&bios_attr_set_interface_driver);
183 }
184
185 MODULE_DEVICE_TABLE(wmi, bios_attr_set_interface_id_table);
186