drivers/platform/x86/dell-wmi-sysman/sysman.c

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