summaryrefslogtreecommitdiffstats
path: root/drivers/platform/x86/dell-wmi-sysman/sysman.c
blob: cb81010ba1a21b108e76fd248ed8bb3ac79c8cb2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
// SPDX-License-Identifier: GPL-2.0
/*
 * Common methods for use with dell-wmi-sysman
 *
 *  Copyright (c) 2020 Dell Inc.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/fs.h>
#include <linux/dmi.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/wmi.h>
#include "dell-wmi-sysman.h"

#define MAX_TYPES  4
#include <linux/nls.h>

static struct class firmware_attributes_class = {
	.name = "firmware-attributes",
};

struct wmi_sysman_priv wmi_priv = {
	.mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
};

/* reset bios to defaults */
static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
static int reset_option = -1;


/**
 * populate_string_buffer() - populates a string buffer
 * @buffer: the start of the destination buffer
 * @buffer_len: length of the destination buffer
 * @str: the string to insert into buffer
 */
ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str)
{
	u16 *length = (u16 *)buffer;
	u16 *target = length + 1;
	int ret;

	ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN,
			      target, buffer_len - sizeof(u16));
	if (ret < 0) {
		dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n");
		return ret;
	}

	if ((ret * sizeof(u16)) > U16_MAX) {
		dev_err(wmi_priv.class_dev, "Error string too long\n");
		return -ERANGE;
	}

	*length = ret * sizeof(u16);
	return sizeof(u16) + *length;
}

/**
 * calculate_string_buffer() - determines size of string buffer for use with BIOS communication
 * @str: the string to calculate based upon
 *
 */
size_t calculate_string_buffer(const char *str)
{
	/* u16 length field + one UTF16 char for each input char */
	return sizeof(u16) + strlen(str) * sizeof(u16);
}

/**
 * calculate_security_buffer() - determines size of security buffer for authentication scheme
 * @authentication: the authentication content
 *
 * Currently only supported type is Admin password
 */
size_t calculate_security_buffer(char *authentication)
{
	if (strlen(authentication) > 0) {
		return (sizeof(u32) * 2) + strlen(authentication) +
			strlen(authentication) % 2;
	}
	return sizeof(u32) * 2;
}

/**
 * populate_security_buffer() - builds a security buffer for authentication scheme
 * @buffer: the buffer to populate
 * @authentication: the authentication content
 *
 * Currently only supported type is PLAIN TEXT
 */
void populate_security_buffer(char *buffer, char *authentication)
{
	char *auth = buffer + sizeof(u32) * 2;
	u32 *sectype = (u32 *) buffer;
	u32 *seclen = sectype + 1;

	*sectype = strlen(authentication) > 0 ? 1 : 0;
	*seclen = strlen(authentication);

	/* plain text */
	if (strlen(authentication) > 0)
		memcpy(auth, authentication, *seclen);
}

/**
 * map_wmi_error() - map errors from WMI methods to kernel error codes
 * @error_code: integer error code returned from Dell's firmware
 */
int map_wmi_error(int error_code)
{
	switch (error_code) {
	case 0:
		/* success */
		return 0;
	case 1:
		/* failed */
		return -EIO;
	case 2:
		/* invalid parameter */
		return -EINVAL;
	case 3:
		/* access denied */
		return -EACCES;
	case 4:
		/* not supported */
		return -EOPNOTSUPP;
	case 5:
		/* memory error */
		return -ENOMEM;
	case 6:
		/* protocol error */
		return -EPROTO;
	}
	/* unspecified error */
	return -EIO;
}

/**
 * reset_bios_show() - sysfs implementaton for read reset_bios
 * @kobj: Kernel object for this attribute
 * @attr: Kernel object attribute
 * @buf: The buffer to display to userspace
 */
static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	char *start = buf;
	int i;

	for (i = 0; i < MAX_TYPES; i++) {
		if (i == reset_option)
			buf += sprintf(buf, "[%s] ", reset_types[i]);
		else
			buf += sprintf(buf, "%s ", reset_types[i]);
	}
	buf += sprintf(buf, "\n");
	return buf-start;
}

/**
 * reset_bios_store() - sysfs implementaton for write reset_bios
 * @kobj: Kernel object for this attribute
 * @attr: Kernel object attribute
 * @buf: The buffer from userspace
 * @count: the size of the buffer from userspace
 */
static ssize_t reset_bios_store(struct kobject *kobj,
				struct kobj_attribute *attr, const char *buf, size_t count)
{
	int type = sysfs_match_string(reset_types, buf);
	int ret;

	if (type < 0)
		return type;

	ret = set_bios_defaults(type);
	pr_debug("reset all attributes request type %d: %d\n", type, ret);
	if (!ret) {
		reset_option = type;
		ret = count;
	}

	return ret;
}

/**
 * pending_reboot_show() - sysfs implementaton for read pending_reboot
 * @kobj: Kernel object for this attribute
 * @attr: Kernel object attribute
 * @buf: The buffer to display to userspace
 *
 * Stores default value as 0
 * When current_value is changed this attribute is set to 1 to notify reboot may be required
 */
static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
				   char *buf)
{
	return sprintf(buf, "%d\n", wmi_priv.pending_changes);
}

static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);


/**
 * create_attributes_level_sysfs_files() - Creates reset_bios and
 * pending_reboot attributes
 */
static int create_attributes_level_sysfs_files(void)
{
	int ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);

	if (ret) {
		pr_debug("could not create reset_bios file\n");
		return ret;
	}

	ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
	if (ret) {
		pr_debug("could not create changing_pending_reboot file\n");
		sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
	}
	return ret;
}

static void release_reset_bios_data(void)
{
	sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
	sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
}

static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr,
				    char *buf)
{
	struct kobj_attribute *kattr;
	ssize_t ret = -EIO;

	kattr = container_of(attr, struct kobj_attribute, attr);
	if (kattr->show)
		ret = kattr->show(kobj, kattr, buf);
	return ret;
}

static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr,
				     const char *buf, size_t count)
{
	struct kobj_attribute *kattr;
	ssize_t ret = -EIO;

	kattr = container_of(attr, struct kobj_attribute, attr);
	if (kattr->store)
		ret = kattr->store(kobj, kattr, buf, count);
	return ret;
}

static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
	.show	= wmi_sysman_attr_show,
	.store	= wmi_sysman_attr_store,
};

static void attr_name_release(struct kobject *kobj)
{
	kfree(kobj);
}

static struct kobj_type attr_name_ktype = {
	.release	= attr_name_release,
	.sysfs_ops	= &wmi_sysman_kobj_sysfs_ops,
};

/**
 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks
 * @dest: Where to copy the string to
 * @src: Where to copy the string from
 */
void strlcpy_attr(char *dest, char *src)
{
	size_t len = strlen(src) + 1;

	if (len > 1 && len <= MAX_BUFF)
		strlcpy(dest, src, len);

	/*len can be zero because any property not-applicable to attribute can
	 * be empty so check only for too long buffers and log error
	 */
	if (len > MAX_BUFF)
		pr_err("Source string returned from BIOS is out of bound!\n");
}

/**
 * get_wmiobj_pointer() - Get Content of WMI block for particular instance
 * @instance_id: WMI instance ID
 * @guid_string: WMI GUID (in str form)
 *
 * Fetches the content for WMI block (instance_id) under GUID (guid_string)
 * Caller must kfree the return
 */
union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
{
	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
	acpi_status status;

	status = wmi_query_block(guid_string, instance_id, &out);

	return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
}

/**
 * get_instance_count() - Compute total number of instances under guid_string
 * @guid_string: WMI GUID (in string form)
 */
int get_instance_count(const char *guid_string)
{
	union acpi_object *wmi_obj = NULL;
	int i = 0;

	do {
		kfree(wmi_obj);
		wmi_obj = get_wmiobj_pointer(i, guid_string);
		i++;
	} while (wmi_obj);

	return (i-1);
}

/**
 * alloc_attributes_data() - Allocate attributes data for a particular type
 * @attr_type: Attribute type to allocate
 */
static int alloc_attributes_data(int attr_type)
{
	int retval = 0;

	switch (attr_type) {
	case ENUM:
		retval = alloc_enum_data();
		break;
	case INT:
		retval = alloc_int_data();
		break;
	case STR:
		retval = alloc_str_data();
		break;
	case PO:
		retval = alloc_po_data();
		break;
	default:
		break;
	}

	return retval;
}

/**
 * destroy_attribute_objs() - Free a kset of kobjects
 * @kset: The kset to destroy
 *
 * Fress kobjects created for each attribute_name under attribute type kset
 */
static void destroy_attribute_objs(struct kset *kset)
{
	struct kobject *pos, *next;

	list_for_each_entry_safe(pos, next, &kset->list, entry) {
		kobject_put(pos);
	}
}

/**
 * release_attributes_data() - Clean-up all sysfs directories and files created
 */
static void release_attributes_data(void)
{
	release_reset_bios_data();

	mutex_lock(&wmi_priv.mutex);
	exit_enum_attributes();
	exit_int_attributes();
	exit_str_attributes();
	exit_po_attributes();
	if (wmi_priv.authentication_dir_kset) {
		destroy_attribute_objs(wmi_priv.authentication_dir_kset);
		kset_unregister(wmi_priv.authentication_dir_kset);
		wmi_priv.authentication_dir_kset = NULL;
	}
	if (wmi_priv.main_dir_kset) {
		destroy_attribute_objs(wmi_priv.main_dir_kset);
		kset_unregister(wmi_priv.main_dir_kset);
	}
	mutex_unlock(&wmi_priv.mutex);

}

/**
 * init_bios_attributes() - Initialize all attributes for a type
 * @attr_type: The attribute type to initialize
 * @guid: The WMI GUID associated with this type to initialize
 *
 * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
 * Populates each attrbute typ's respective properties under sysfs files
 */
static int init_bios_attributes(int attr_type, const char *guid)
{
	struct kobject *attr_name_kobj; //individual attribute names
	union acpi_object *obj = NULL;
	union acpi_object *elements;
	struct kset *tmp_set;

	/* instance_id needs to be reset for each type GUID
	 * also, instance IDs are unique within GUID but not across
	 */
	int instance_id = 0;
	int retval = 0;

	retval = alloc_attributes_data(attr_type);
	if (retval)
		return retval;
	/* need to use specific instance_id and guid combination to get right data */
	obj = get_wmiobj_pointer(instance_id, guid);
	if (!obj || obj->type != ACPI_TYPE_PACKAGE)
		return -ENODEV;
	elements = obj->package.elements;

	mutex_lock(&wmi_priv.mutex);
	while (elements) {
		/* sanity checking */
		if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {
			pr_debug("incorrect element type\n");
			goto nextobj;
		}
		if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
			pr_debug("empty attribute found\n");
			goto nextobj;
		}
		if (attr_type == PO)
			tmp_set = wmi_priv.authentication_dir_kset;
		else
			tmp_set = wmi_priv.main_dir_kset;

		if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) {
			pr_debug("duplicate attribute name found - %s\n",
				elements[ATTR_NAME].string.pointer);
			goto nextobj;
		}

		/* build attribute */
		attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
		if (!attr_name_kobj) {
			retval = -ENOMEM;
			goto err_attr_init;
		}

		attr_name_kobj->kset = tmp_set;

		retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
						elements[ATTR_NAME].string.pointer);
		if (retval) {
			kobject_put(attr_name_kobj);
			goto err_attr_init;
		}

		/* enumerate all of this attribute */
		switch (attr_type) {
		case ENUM:
			retval = populate_enum_data(elements, instance_id, attr_name_kobj);
			break;
		case INT:
			retval = populate_int_data(elements, instance_id, attr_name_kobj);
			break;
		case STR:
			retval = populate_str_data(elements, instance_id, attr_name_kobj);
			break;
		case PO:
			retval = populate_po_data(elements, instance_id, attr_name_kobj);
			break;
		default:
			break;
		}

		if (retval) {
			pr_debug("failed to populate %s\n",
				elements[ATTR_NAME].string.pointer);
			goto err_attr_init;
		}

nextobj:
		kfree(obj);
		instance_id++;
		obj = get_wmiobj_pointer(instance_id, guid);
		elements = obj ? obj->package.elements : NULL;
	}

	mutex_unlock(&wmi_priv.mutex);
	return 0;

err_attr_init:
	mutex_unlock(&wmi_priv.mutex);
	release_attributes_data();
	kfree(obj);
	return retval;
}

static int __init sysman_init(void)
{
	int ret = 0;

	if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
	    !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
		pr_err("Unable to run on non-Dell system\n");
		return -ENODEV;
	}

	ret = init_bios_attr_set_interface();
	if (ret || !wmi_priv.bios_attr_wdev) {
		pr_debug("failed to initialize set interface\n");
		goto fail_set_interface;
	}

	ret = init_bios_attr_pass_interface();
	if (ret || !wmi_priv.password_attr_wdev) {
		pr_debug("failed to initialize pass interface\n");
		goto fail_pass_interface;
	}

	ret = class_register(&firmware_attributes_class);
	if (ret)
		goto fail_class;

	wmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
				  NULL, "%s", DRIVER_NAME);
	if (IS_ERR(wmi_priv.class_dev)) {
		ret = PTR_ERR(wmi_priv.class_dev);
		goto fail_classdev;
	}

	wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,
						     &wmi_priv.class_dev->kobj);
	if (!wmi_priv.main_dir_kset) {
		ret = -ENOMEM;
		goto fail_main_kset;
	}

	wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
								&wmi_priv.class_dev->kobj);
	if (!wmi_priv.authentication_dir_kset) {
		ret = -ENOMEM;
		goto fail_authentication_kset;
	}

	ret = create_attributes_level_sysfs_files();
	if (ret) {
		pr_debug("could not create reset BIOS attribute\n");
		goto fail_reset_bios;
	}

	ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
	if (ret) {
		pr_debug("failed to populate enumeration type attributes\n");
		goto fail_create_group;
	}

	ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
	if (ret) {
		pr_debug("failed to populate integer type attributes\n");
		goto fail_create_group;
	}

	ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
	if (ret) {
		pr_debug("failed to populate string type attributes\n");
		goto fail_create_group;
	}

	ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
	if (ret) {
		pr_debug("failed to populate pass object type attributes\n");
		goto fail_create_group;
	}

	return 0;

fail_create_group:
	release_attributes_data();

fail_reset_bios:
	if (wmi_priv.authentication_dir_kset) {
		kset_unregister(wmi_priv.authentication_dir_kset);
		wmi_priv.authentication_dir_kset = NULL;
	}

fail_authentication_kset:
	if (wmi_priv.main_dir_kset) {
		kset_unregister(wmi_priv.main_dir_kset);
		wmi_priv.main_dir_kset = NULL;
	}

fail_main_kset:
	device_destroy(&firmware_attributes_class, MKDEV(0, 0));

fail_classdev:
	class_unregister(&firmware_attributes_class);

fail_class:
	exit_bios_attr_pass_interface();

fail_pass_interface:
	exit_bios_attr_set_interface();

fail_set_interface:
	return ret;
}

static void __exit sysman_exit(void)
{
	release_attributes_data();
	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
	class_unregister(&firmware_attributes_class);
	exit_bios_attr_set_interface();
	exit_bios_attr_pass_interface();
}

module_init(sysman_init);
module_exit(sysman_exit);

MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");
MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");
MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");
MODULE_DESCRIPTION("Dell platform setting control interface");
MODULE_LICENSE("GPL");