1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Functions corresponding to string type attributes under
4 * HP_WMI_BIOS_STRING_GUID for use with hp-bioscfg driver.
5 *
6 * Copyright (c) 2022 HP Development Company, L.P.
7 */
8
9 #include "bioscfg.h"
10
11 #define WMI_STRING_TYPE "HPBIOS_BIOSString"
12
13 GET_INSTANCE_ID(string);
14
current_value_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)15 static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
16 {
17 int instance_id = get_string_instance_id(kobj);
18
19 if (instance_id < 0)
20 return -EIO;
21
22 return sysfs_emit(buf, "%s\n",
23 bioscfg_drv.string_data[instance_id].current_value);
24 }
25
26 /**
27 * validate_string_input() -
28 * Validate input of current_value against min and max lengths
29 *
30 * @instance_id: The instance on which input is validated
31 * @buf: Input value
32 */
validate_string_input(int instance_id,const char * buf)33 static int validate_string_input(int instance_id, const char *buf)
34 {
35 int in_len = strlen(buf);
36 struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
37
38 /* BIOS treats it as a read only attribute */
39 if (string_data->common.is_readonly)
40 return -EIO;
41
42 if (in_len < string_data->min_length || in_len > string_data->max_length)
43 return -ERANGE;
44
45 return 0;
46 }
47
update_string_value(int instance_id,char * attr_value)48 static void update_string_value(int instance_id, char *attr_value)
49 {
50 struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
51
52 /* Write settings to BIOS */
53 strscpy(string_data->current_value, attr_value, sizeof(string_data->current_value));
54 }
55
56 /*
57 * ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name_language_code, string);
58 * static struct kobj_attribute string_display_langcode =
59 * __ATTR_RO(display_name_language_code);
60 */
61
62 ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name, string);
63 static struct kobj_attribute string_display_name =
64 __ATTR_RO(display_name);
65
66 ATTRIBUTE_PROPERTY_STORE(current_value, string);
67 static struct kobj_attribute string_current_val =
68 __ATTR_RW_MODE(current_value, 0644);
69
70 ATTRIBUTE_N_PROPERTY_SHOW(min_length, string);
71 static struct kobj_attribute string_min_length =
72 __ATTR_RO(min_length);
73
74 ATTRIBUTE_N_PROPERTY_SHOW(max_length, string);
75 static struct kobj_attribute string_max_length =
76 __ATTR_RO(max_length);
77
type_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)78 static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
79 char *buf)
80 {
81 return sysfs_emit(buf, "string\n");
82 }
83
84 static struct kobj_attribute string_type =
85 __ATTR_RO(type);
86
87 static struct attribute *string_attrs[] = {
88 &common_display_langcode.attr,
89 &string_display_name.attr,
90 &string_current_val.attr,
91 &string_min_length.attr,
92 &string_max_length.attr,
93 &string_type.attr,
94 NULL
95 };
96
97 static const struct attribute_group string_attr_group = {
98 .attrs = string_attrs,
99 };
100
hp_alloc_string_data(void)101 int hp_alloc_string_data(void)
102 {
103 bioscfg_drv.string_instances_count = hp_get_instance_count(HP_WMI_BIOS_STRING_GUID);
104 bioscfg_drv.string_data = kcalloc(bioscfg_drv.string_instances_count,
105 sizeof(*bioscfg_drv.string_data), GFP_KERNEL);
106 if (!bioscfg_drv.string_data) {
107 bioscfg_drv.string_instances_count = 0;
108 return -ENOMEM;
109 }
110 return 0;
111 }
112
113 /* Expected Values types associated with each element */
114 static const acpi_object_type expected_string_types[] = {
115 [NAME] = ACPI_TYPE_STRING,
116 [VALUE] = ACPI_TYPE_STRING,
117 [PATH] = ACPI_TYPE_STRING,
118 [IS_READONLY] = ACPI_TYPE_INTEGER,
119 [DISPLAY_IN_UI] = ACPI_TYPE_INTEGER,
120 [REQUIRES_PHYSICAL_PRESENCE] = ACPI_TYPE_INTEGER,
121 [SEQUENCE] = ACPI_TYPE_INTEGER,
122 [PREREQUISITES_SIZE] = ACPI_TYPE_INTEGER,
123 [PREREQUISITES] = ACPI_TYPE_STRING,
124 [SECURITY_LEVEL] = ACPI_TYPE_INTEGER,
125 [STR_MIN_LENGTH] = ACPI_TYPE_INTEGER,
126 [STR_MAX_LENGTH] = ACPI_TYPE_INTEGER,
127 };
128
hp_populate_string_elements_from_package(union acpi_object * string_obj,int string_obj_count,int instance_id)129 static int hp_populate_string_elements_from_package(union acpi_object *string_obj,
130 int string_obj_count,
131 int instance_id)
132 {
133 char *str_value = NULL;
134 int value_len;
135 int ret = 0;
136 u32 int_value = 0;
137 int elem;
138 int reqs;
139 int eloc;
140 int size;
141 struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
142
143 if (!string_obj)
144 return -EINVAL;
145
146 for (elem = 1, eloc = 1; elem < string_obj_count; elem++, eloc++) {
147 /* ONLY look at the first STRING_ELEM_CNT elements */
148 if (eloc == STR_ELEM_CNT)
149 goto exit_string_package;
150
151 switch (string_obj[elem].type) {
152 case ACPI_TYPE_STRING:
153 if (elem != PREREQUISITES) {
154 ret = hp_convert_hexstr_to_str(string_obj[elem].string.pointer,
155 string_obj[elem].string.length,
156 &str_value, &value_len);
157
158 if (ret)
159 continue;
160 }
161 break;
162 case ACPI_TYPE_INTEGER:
163 int_value = (u32)string_obj[elem].integer.value;
164 break;
165 default:
166 pr_warn("Unsupported object type [%d]\n", string_obj[elem].type);
167 continue;
168 }
169
170 /* Check that both expected and read object type match */
171 if (expected_string_types[eloc] != string_obj[elem].type) {
172 pr_err("Error expected type %d for elem %d, but got type %d instead\n",
173 expected_string_types[eloc], elem, string_obj[elem].type);
174 kfree(str_value);
175 return -EIO;
176 }
177
178 /* Assign appropriate element value to corresponding field*/
179 switch (eloc) {
180 case VALUE:
181 strscpy(string_data->current_value,
182 str_value, sizeof(string_data->current_value));
183 break;
184 case PATH:
185 strscpy(string_data->common.path, str_value,
186 sizeof(string_data->common.path));
187 break;
188 case IS_READONLY:
189 string_data->common.is_readonly = int_value;
190 break;
191 case DISPLAY_IN_UI:
192 string_data->common.display_in_ui = int_value;
193 break;
194 case REQUIRES_PHYSICAL_PRESENCE:
195 string_data->common.requires_physical_presence = int_value;
196 break;
197 case SEQUENCE:
198 string_data->common.sequence = int_value;
199 break;
200 case PREREQUISITES_SIZE:
201 if (int_value > MAX_PREREQUISITES_SIZE) {
202 pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
203 int_value = MAX_PREREQUISITES_SIZE;
204 }
205 string_data->common.prerequisites_size = int_value;
206
207 /*
208 * This step is needed to keep the expected
209 * element list pointing to the right obj[elem].type
210 * when the size is zero. PREREQUISITES
211 * object is omitted by BIOS when the size is
212 * zero.
213 */
214 if (string_data->common.prerequisites_size == 0)
215 eloc++;
216 break;
217 case PREREQUISITES:
218 size = min_t(u32, string_data->common.prerequisites_size,
219 MAX_PREREQUISITES_SIZE);
220
221 for (reqs = 0; reqs < size; reqs++) {
222 if (elem >= string_obj_count) {
223 pr_err("Error elem-objects package is too small\n");
224 return -EINVAL;
225 }
226
227 ret = hp_convert_hexstr_to_str(string_obj[elem + reqs].string.pointer,
228 string_obj[elem + reqs].string.length,
229 &str_value, &value_len);
230
231 if (ret)
232 continue;
233
234 strscpy(string_data->common.prerequisites[reqs],
235 str_value,
236 sizeof(string_data->common.prerequisites[reqs]));
237 kfree(str_value);
238 str_value = NULL;
239 }
240 break;
241
242 case SECURITY_LEVEL:
243 string_data->common.security_level = int_value;
244 break;
245 case STR_MIN_LENGTH:
246 string_data->min_length = int_value;
247 break;
248 case STR_MAX_LENGTH:
249 string_data->max_length = int_value;
250 break;
251 default:
252 pr_warn("Invalid element: %d found in String attribute or data may be malformed\n", elem);
253 break;
254 }
255
256 kfree(str_value);
257 str_value = NULL;
258 }
259
260 exit_string_package:
261 kfree(str_value);
262 return 0;
263 }
264
265 /**
266 * hp_populate_string_package_data() -
267 * Populate all properties of an instance under string attribute
268 *
269 * @string_obj: ACPI object with string data
270 * @instance_id: The instance to enumerate
271 * @attr_name_kobj: The parent kernel object
272 */
hp_populate_string_package_data(union acpi_object * string_obj,int instance_id,struct kobject * attr_name_kobj)273 int hp_populate_string_package_data(union acpi_object *string_obj,
274 int instance_id,
275 struct kobject *attr_name_kobj)
276 {
277 struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
278
279 string_data->attr_name_kobj = attr_name_kobj;
280
281 hp_populate_string_elements_from_package(string_obj,
282 string_obj->package.count,
283 instance_id);
284
285 hp_update_attribute_permissions(string_data->common.is_readonly,
286 &string_current_val);
287 hp_friendly_user_name_update(string_data->common.path,
288 attr_name_kobj->name,
289 string_data->common.display_name,
290 sizeof(string_data->common.display_name));
291 return sysfs_create_group(attr_name_kobj, &string_attr_group);
292 }
293
hp_populate_string_elements_from_buffer(u8 * buffer_ptr,u32 * buffer_size,int instance_id)294 static int hp_populate_string_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
295 int instance_id)
296 {
297 int ret = 0;
298 struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
299
300 /*
301 * Only data relevant to this driver and its functionality is
302 * read. BIOS defines the order in which each * element is
303 * read. Element 0 data is not relevant to this
304 * driver hence it is ignored. For clarity, all element names
305 * (DISPLAY_IN_UI) which defines the order in which is read
306 * and the name matches the variable where the data is stored.
307 *
308 * In earlier implementation, reported errors were ignored
309 * causing the data to remain uninitialized. It is not
310 * possible to determine if data read from BIOS is valid or
311 * not. It is for this reason functions may return a error
312 * without validating the data itself.
313 */
314
315 // VALUE:
316 ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size, string_data->current_value,
317 sizeof(string_data->current_value));
318 if (ret < 0)
319 goto buffer_exit;
320
321 // COMMON:
322 ret = hp_get_common_data_from_buffer(&buffer_ptr, buffer_size, &string_data->common);
323 if (ret < 0)
324 goto buffer_exit;
325
326 // STR_MIN_LENGTH:
327 ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
328 &string_data->min_length);
329 if (ret < 0)
330 goto buffer_exit;
331
332 // STR_MAX_LENGTH:
333 ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
334 &string_data->max_length);
335
336 buffer_exit:
337
338 return ret;
339 }
340
341 /**
342 * hp_populate_string_buffer_data() -
343 * Populate all properties of an instance under string attribute
344 *
345 * @buffer_ptr: Buffer pointer
346 * @buffer_size: Buffer size
347 * @instance_id: The instance to enumerate
348 * @attr_name_kobj: The parent kernel object
349 */
hp_populate_string_buffer_data(u8 * buffer_ptr,u32 * buffer_size,int instance_id,struct kobject * attr_name_kobj)350 int hp_populate_string_buffer_data(u8 *buffer_ptr, u32 *buffer_size,
351 int instance_id,
352 struct kobject *attr_name_kobj)
353 {
354 struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
355 int ret = 0;
356
357 string_data->attr_name_kobj = attr_name_kobj;
358
359 ret = hp_populate_string_elements_from_buffer(buffer_ptr, buffer_size,
360 instance_id);
361 if (ret < 0)
362 return ret;
363
364 hp_update_attribute_permissions(string_data->common.is_readonly,
365 &string_current_val);
366 hp_friendly_user_name_update(string_data->common.path,
367 attr_name_kobj->name,
368 string_data->common.display_name,
369 sizeof(string_data->common.display_name));
370
371 return sysfs_create_group(attr_name_kobj, &string_attr_group);
372 }
373
374 /**
375 * hp_exit_string_attributes() - Clear all attribute data
376 *
377 * Clears all data allocated for this group of attributes
378 */
hp_exit_string_attributes(void)379 void hp_exit_string_attributes(void)
380 {
381 int instance_id;
382
383 for (instance_id = 0; instance_id < bioscfg_drv.string_instances_count;
384 instance_id++) {
385 struct kobject *attr_name_kobj =
386 bioscfg_drv.string_data[instance_id].attr_name_kobj;
387
388 if (attr_name_kobj)
389 sysfs_remove_group(attr_name_kobj, &string_attr_group);
390 }
391 bioscfg_drv.string_instances_count = 0;
392
393 kfree(bioscfg_drv.string_data);
394 bioscfg_drv.string_data = NULL;
395 }
396