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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Common methods for use with dell-wmi-sysman
4 *
5 * Copyright (c) 2020 Dell Inc.
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/fs.h>
11#include <linux/dmi.h>
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/wmi.h>
15#include "dell-wmi-sysman.h"
16#include "../../firmware_attributes_class.h"
17
18#define MAX_TYPES 4
19#include <linux/nls.h>
20
21struct wmi_sysman_priv wmi_priv = {
22 .mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
23};
24
25/* reset bios to defaults */
26static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
27static int reset_option = -1;
28static struct class *fw_attr_class;
29
30
31/**
32 * populate_string_buffer() - populates a string buffer
33 * @buffer: the start of the destination buffer
34 * @buffer_len: length of the destination buffer
35 * @str: the string to insert into buffer
36 */
37ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str)
38{
39 u16 *length = (u16 *)buffer;
40 u16 *target = length + 1;
41 int ret;
42
43 ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN,
44 target, buffer_len - sizeof(u16));
45 if (ret < 0) {
46 dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n");
47 return ret;
48 }
49
50 if ((ret * sizeof(u16)) > U16_MAX) {
51 dev_err(wmi_priv.class_dev, "Error string too long\n");
52 return -ERANGE;
53 }
54
55 *length = ret * sizeof(u16);
56 return sizeof(u16) + *length;
57}
58
59/**
60 * calculate_string_buffer() - determines size of string buffer for use with BIOS communication
61 * @str: the string to calculate based upon
62 *
63 */
64size_t calculate_string_buffer(const char *str)
65{
66 /* u16 length field + one UTF16 char for each input char */
67 return sizeof(u16) + strlen(str) * sizeof(u16);
68}
69
70/**
71 * calculate_security_buffer() - determines size of security buffer for authentication scheme
72 * @authentication: the authentication content
73 *
74 * Currently only supported type is Admin password
75 */
76size_t calculate_security_buffer(char *authentication)
77{
78 if (strlen(authentication) > 0) {
79 return (sizeof(u32) * 2) + strlen(authentication) +
80 strlen(authentication) % 2;
81 }
82 return sizeof(u32) * 2;
83}
84
85/**
86 * populate_security_buffer() - builds a security buffer for authentication scheme
87 * @buffer: the buffer to populate
88 * @authentication: the authentication content
89 *
90 * Currently only supported type is PLAIN TEXT
91 */
92void populate_security_buffer(char *buffer, char *authentication)
93{
94 char *auth = buffer + sizeof(u32) * 2;
95 u32 *sectype = (u32 *) buffer;
96 u32 *seclen = sectype + 1;
97
98 *sectype = strlen(authentication) > 0 ? 1 : 0;
99 *seclen = strlen(authentication);
100
101 /* plain text */
102 if (strlen(authentication) > 0)
103 memcpy(auth, authentication, *seclen);
104}
105
106/**
107 * map_wmi_error() - map errors from WMI methods to kernel error codes
108 * @error_code: integer error code returned from Dell's firmware
109 */
110int map_wmi_error(int error_code)
111{
112 switch (error_code) {
113 case 0:
114 /* success */
115 return 0;
116 case 1:
117 /* failed */
118 return -EIO;
119 case 2:
120 /* invalid parameter */
121 return -EINVAL;
122 case 3:
123 /* access denied */
124 return -EACCES;
125 case 4:
126 /* not supported */
127 return -EOPNOTSUPP;
128 case 5:
129 /* memory error */
130 return -ENOMEM;
131 case 6:
132 /* protocol error */
133 return -EPROTO;
134 }
135 /* unspecified error */
136 return -EIO;
137}
138
139/**
140 * reset_bios_show() - sysfs implementaton for read reset_bios
141 * @kobj: Kernel object for this attribute
142 * @attr: Kernel object attribute
143 * @buf: The buffer to display to userspace
144 */
145static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
146{
147 char *start = buf;
148 int i;
149
150 for (i = 0; i < MAX_TYPES; i++) {
151 if (i == reset_option)
152 buf += sprintf(buf, "[%s] ", reset_types[i]);
153 else
154 buf += sprintf(buf, "%s ", reset_types[i]);
155 }
156 buf += sprintf(buf, "\n");
157 return buf-start;
158}
159
160/**
161 * reset_bios_store() - sysfs implementaton for write reset_bios
162 * @kobj: Kernel object for this attribute
163 * @attr: Kernel object attribute
164 * @buf: The buffer from userspace
165 * @count: the size of the buffer from userspace
166 */
167static ssize_t reset_bios_store(struct kobject *kobj,
168 struct kobj_attribute *attr, const char *buf, size_t count)
169{
170 int type = sysfs_match_string(reset_types, buf);
171 int ret;
172
173 if (type < 0)
174 return type;
175
176 ret = set_bios_defaults(type);
177 pr_debug("reset all attributes request type %d: %d\n", type, ret);
178 if (!ret) {
179 reset_option = type;
180 ret = count;
181 }
182
183 return ret;
184}
185
186/**
187 * pending_reboot_show() - sysfs implementaton for read pending_reboot
188 * @kobj: Kernel object for this attribute
189 * @attr: Kernel object attribute
190 * @buf: The buffer to display to userspace
191 *
192 * Stores default value as 0
193 * When current_value is changed this attribute is set to 1 to notify reboot may be required
194 */
195static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
196 char *buf)
197{
198 return sprintf(buf, "%d\n", wmi_priv.pending_changes);
199}
200
201static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
202static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
203
204
205/**
206 * create_attributes_level_sysfs_files() - Creates reset_bios and
207 * pending_reboot attributes
208 */
209static int create_attributes_level_sysfs_files(void)
210{
211 int ret;
212
213 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
214 if (ret)
215 return ret;
216
217 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
218 if (ret)
219 return ret;
220
221 return 0;
222}
223
224static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr,
225 char *buf)
226{
227 struct kobj_attribute *kattr;
228 ssize_t ret = -EIO;
229
230 kattr = container_of(attr, struct kobj_attribute, attr);
231 if (kattr->show)
232 ret = kattr->show(kobj, kattr, buf);
233 return ret;
234}
235
236static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr,
237 const char *buf, size_t count)
238{
239 struct kobj_attribute *kattr;
240 ssize_t ret = -EIO;
241
242 kattr = container_of(attr, struct kobj_attribute, attr);
243 if (kattr->store)
244 ret = kattr->store(kobj, kattr, buf, count);
245 return ret;
246}
247
248static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
249 .show = wmi_sysman_attr_show,
250 .store = wmi_sysman_attr_store,
251};
252
253static void attr_name_release(struct kobject *kobj)
254{
255 kfree(kobj);
256}
257
258static struct kobj_type attr_name_ktype = {
259 .release = attr_name_release,
260 .sysfs_ops = &wmi_sysman_kobj_sysfs_ops,
261};
262
263/**
264 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks
265 * @dest: Where to copy the string to
266 * @src: Where to copy the string from
267 */
268void strlcpy_attr(char *dest, char *src)
269{
270 size_t len = strlen(src) + 1;
271
272 if (len > 1 && len <= MAX_BUFF)
273 strscpy(dest, src, len);
274
275 /*len can be zero because any property not-applicable to attribute can
276 * be empty so check only for too long buffers and log error
277 */
278 if (len > MAX_BUFF)
279 pr_err("Source string returned from BIOS is out of bound!\n");
280}
281
282/**
283 * get_wmiobj_pointer() - Get Content of WMI block for particular instance
284 * @instance_id: WMI instance ID
285 * @guid_string: WMI GUID (in str form)
286 *
287 * Fetches the content for WMI block (instance_id) under GUID (guid_string)
288 * Caller must kfree the return
289 */
290union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
291{
292 struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
293 acpi_status status;
294
295 status = wmi_query_block(guid_string, instance_id, &out);
296
297 return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
298}
299
300/**
301 * get_instance_count() - Compute total number of instances under guid_string
302 * @guid_string: WMI GUID (in string form)
303 */
304int get_instance_count(const char *guid_string)
305{
306 union acpi_object *wmi_obj = NULL;
307 int i = 0;
308
309 do {
310 kfree(wmi_obj);
311 wmi_obj = get_wmiobj_pointer(i, guid_string);
312 i++;
313 } while (wmi_obj);
314
315 return (i-1);
316}
317
318/**
319 * alloc_attributes_data() - Allocate attributes data for a particular type
320 * @attr_type: Attribute type to allocate
321 */
322static int alloc_attributes_data(int attr_type)
323{
324 int retval = 0;
325
326 switch (attr_type) {
327 case ENUM:
328 retval = alloc_enum_data();
329 break;
330 case INT:
331 retval = alloc_int_data();
332 break;
333 case STR:
334 retval = alloc_str_data();
335 break;
336 case PO:
337 retval = alloc_po_data();
338 break;
339 default:
340 break;
341 }
342
343 return retval;
344}
345
346/**
347 * destroy_attribute_objs() - Free a kset of kobjects
348 * @kset: The kset to destroy
349 *
350 * Fress kobjects created for each attribute_name under attribute type kset
351 */
352static void destroy_attribute_objs(struct kset *kset)
353{
354 struct kobject *pos, *next;
355
356 list_for_each_entry_safe(pos, next, &kset->list, entry) {
357 kobject_put(pos);
358 }
359}
360
361/**
362 * release_attributes_data() - Clean-up all sysfs directories and files created
363 */
364static void release_attributes_data(void)
365{
366 mutex_lock(&wmi_priv.mutex);
367 exit_enum_attributes();
368 exit_int_attributes();
369 exit_str_attributes();
370 exit_po_attributes();
371 if (wmi_priv.authentication_dir_kset) {
372 destroy_attribute_objs(wmi_priv.authentication_dir_kset);
373 kset_unregister(wmi_priv.authentication_dir_kset);
374 wmi_priv.authentication_dir_kset = NULL;
375 }
376 if (wmi_priv.main_dir_kset) {
377 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
378 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
379 destroy_attribute_objs(wmi_priv.main_dir_kset);
380 kset_unregister(wmi_priv.main_dir_kset);
381 wmi_priv.main_dir_kset = NULL;
382 }
383 mutex_unlock(&wmi_priv.mutex);
384}
385
386/**
387 * init_bios_attributes() - Initialize all attributes for a type
388 * @attr_type: The attribute type to initialize
389 * @guid: The WMI GUID associated with this type to initialize
390 *
391 * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
392 * Populates each attrbute typ's respective properties under sysfs files
393 */
394static int init_bios_attributes(int attr_type, const char *guid)
395{
396 struct kobject *attr_name_kobj; //individual attribute names
397 union acpi_object *obj = NULL;
398 union acpi_object *elements;
399 struct kset *tmp_set;
400 int min_elements;
401
402 /* instance_id needs to be reset for each type GUID
403 * also, instance IDs are unique within GUID but not across
404 */
405 int instance_id = 0;
406 int retval = 0;
407
408 retval = alloc_attributes_data(attr_type);
409 if (retval)
410 return retval;
411
412 switch (attr_type) {
413 case ENUM: min_elements = 8; break;
414 case INT: min_elements = 9; break;
415 case STR: min_elements = 8; break;
416 case PO: min_elements = 4; break;
417 default:
418 pr_err("Error: Unknown attr_type: %d\n", attr_type);
419 return -EINVAL;
420 }
421
422 /* need to use specific instance_id and guid combination to get right data */
423 obj = get_wmiobj_pointer(instance_id, guid);
424 if (!obj)
425 return -ENODEV;
426
427 mutex_lock(&wmi_priv.mutex);
428 while (obj) {
429 if (obj->type != ACPI_TYPE_PACKAGE) {
430 pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type);
431 retval = -EIO;
432 goto err_attr_init;
433 }
434
435 if (obj->package.count < min_elements) {
436 pr_err("Error: ACPI-package does not have enough elements: %d < %d\n",
437 obj->package.count, min_elements);
438 goto nextobj;
439 }
440
441 elements = obj->package.elements;
442
443 /* sanity checking */
444 if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {
445 pr_debug("incorrect element type\n");
446 goto nextobj;
447 }
448 if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
449 pr_debug("empty attribute found\n");
450 goto nextobj;
451 }
452 if (attr_type == PO)
453 tmp_set = wmi_priv.authentication_dir_kset;
454 else
455 tmp_set = wmi_priv.main_dir_kset;
456
457 if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) {
458 pr_debug("duplicate attribute name found - %s\n",
459 elements[ATTR_NAME].string.pointer);
460 goto nextobj;
461 }
462
463 /* build attribute */
464 attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
465 if (!attr_name_kobj) {
466 retval = -ENOMEM;
467 goto err_attr_init;
468 }
469
470 attr_name_kobj->kset = tmp_set;
471
472 retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
473 elements[ATTR_NAME].string.pointer);
474 if (retval) {
475 kobject_put(attr_name_kobj);
476 goto err_attr_init;
477 }
478
479 /* enumerate all of this attribute */
480 switch (attr_type) {
481 case ENUM:
482 retval = populate_enum_data(elements, instance_id, attr_name_kobj,
483 obj->package.count);
484 break;
485 case INT:
486 retval = populate_int_data(elements, instance_id, attr_name_kobj);
487 break;
488 case STR:
489 retval = populate_str_data(elements, instance_id, attr_name_kobj);
490 break;
491 case PO:
492 retval = populate_po_data(elements, instance_id, attr_name_kobj);
493 break;
494 default:
495 break;
496 }
497
498 if (retval) {
499 pr_debug("failed to populate %s\n",
500 elements[ATTR_NAME].string.pointer);
501 goto err_attr_init;
502 }
503
504nextobj:
505 kfree(obj);
506 instance_id++;
507 obj = get_wmiobj_pointer(instance_id, guid);
508 }
509
510 mutex_unlock(&wmi_priv.mutex);
511 return 0;
512
513err_attr_init:
514 mutex_unlock(&wmi_priv.mutex);
515 kfree(obj);
516 return retval;
517}
518
519static int __init sysman_init(void)
520{
521 int ret = 0;
522
523 if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
524 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
525 pr_err("Unable to run on non-Dell system\n");
526 return -ENODEV;
527 }
528
529 ret = init_bios_attr_set_interface();
530 if (ret)
531 return ret;
532
533 ret = init_bios_attr_pass_interface();
534 if (ret)
535 goto err_exit_bios_attr_set_interface;
536
537 if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
538 pr_debug("failed to find set or pass interface\n");
539 ret = -ENODEV;
540 goto err_exit_bios_attr_pass_interface;
541 }
542
543 ret = fw_attributes_class_get(&fw_attr_class);
544 if (ret)
545 goto err_exit_bios_attr_pass_interface;
546
547 wmi_priv.class_dev = device_create(fw_attr_class, NULL, MKDEV(0, 0),
548 NULL, "%s", DRIVER_NAME);
549 if (IS_ERR(wmi_priv.class_dev)) {
550 ret = PTR_ERR(wmi_priv.class_dev);
551 goto err_unregister_class;
552 }
553
554 wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,
555 &wmi_priv.class_dev->kobj);
556 if (!wmi_priv.main_dir_kset) {
557 ret = -ENOMEM;
558 goto err_destroy_classdev;
559 }
560
561 wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
562 &wmi_priv.class_dev->kobj);
563 if (!wmi_priv.authentication_dir_kset) {
564 ret = -ENOMEM;
565 goto err_release_attributes_data;
566 }
567
568 ret = create_attributes_level_sysfs_files();
569 if (ret) {
570 pr_debug("could not create reset BIOS attribute\n");
571 goto err_release_attributes_data;
572 }
573
574 ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
575 if (ret) {
576 pr_debug("failed to populate enumeration type attributes\n");
577 goto err_release_attributes_data;
578 }
579
580 ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
581 if (ret) {
582 pr_debug("failed to populate integer type attributes\n");
583 goto err_release_attributes_data;
584 }
585
586 ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
587 if (ret) {
588 pr_debug("failed to populate string type attributes\n");
589 goto err_release_attributes_data;
590 }
591
592 ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
593 if (ret) {
594 pr_debug("failed to populate pass object type attributes\n");
595 goto err_release_attributes_data;
596 }
597
598 return 0;
599
600err_release_attributes_data:
601 release_attributes_data();
602
603err_destroy_classdev:
604 device_destroy(fw_attr_class, MKDEV(0, 0));
605
606err_unregister_class:
607 fw_attributes_class_put();
608
609err_exit_bios_attr_pass_interface:
610 exit_bios_attr_pass_interface();
611
612err_exit_bios_attr_set_interface:
613 exit_bios_attr_set_interface();
614
615 return ret;
616}
617
618static void __exit sysman_exit(void)
619{
620 release_attributes_data();
621 device_destroy(fw_attr_class, MKDEV(0, 0));
622 fw_attributes_class_put();
623 exit_bios_attr_set_interface();
624 exit_bios_attr_pass_interface();
625}
626
627module_init(sysman_init);
628module_exit(sysman_exit);
629
630MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
631MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");
632MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");
633MODULE_DESCRIPTION("Dell platform setting control interface");
634MODULE_LICENSE("GPL");