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
13GET_INSTANCE_ID(string);
14
15static 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 */
33static 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
48static 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
62ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name, string);
63static struct kobj_attribute string_display_name =
64	__ATTR_RO(display_name);
65
66ATTRIBUTE_PROPERTY_STORE(current_value, string);
67static struct kobj_attribute string_current_val =
68	__ATTR_RW_MODE(current_value, 0644);
69
70ATTRIBUTE_N_PROPERTY_SHOW(min_length, string);
71static struct kobj_attribute string_min_length =
72	__ATTR_RO(min_length);
73
74ATTRIBUTE_N_PROPERTY_SHOW(max_length, string);
75static struct kobj_attribute string_max_length =
76	__ATTR_RO(max_length);
77
78static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
79			 char *buf)
80{
81	return sysfs_emit(buf, "string\n");
82}
83
84static struct kobj_attribute string_type =
85	__ATTR_RO(type);
86
87static 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
97static const struct attribute_group string_attr_group = {
98	.attrs = string_attrs,
99};
100
101int 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 */
114static 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
129static 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
260exit_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 */
273int 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
294static 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
336buffer_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 */
350int 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 */
379void 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