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1// SPDX-License-Identifier: GPL-2.02/*3 * Common methods for use with dell-wmi-sysman4 *5 * Copyright (c) 2020 Dell Inc.6 */7 8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt9 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 419#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 const struct class *fw_attr_class;29 30 31/**32 * populate_string_buffer() - populates a string buffer33 * @buffer: the start of the destination buffer34 * @buffer_len: length of the destination buffer35 * @str: the string to insert into buffer36 */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 communication61 * @str: the string to calculate based upon62 *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 scheme72 * @authentication: the authentication content73 *74 * Currently only supported type is Admin password75 */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 scheme87 * @buffer: the buffer to populate88 * @authentication: the authentication content89 *90 * Currently only supported type is PLAIN TEXT91 */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 codes108 * @error_code: integer error code returned from Dell's firmware109 */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_bios141 * @kobj: Kernel object for this attribute142 * @attr: Kernel object attribute143 * @buf: The buffer to display to userspace144 */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 else154 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_bios162 * @kobj: Kernel object for this attribute163 * @attr: Kernel object attribute164 * @buf: The buffer from userspace165 * @count: the size of the buffer from userspace166 */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_reboot188 * @kobj: Kernel object for this attribute189 * @attr: Kernel object attribute190 * @buf: The buffer to display to userspace191 *192 * Stores default value as 0193 * When current_value is changed this attribute is set to 1 to notify reboot may be required194 */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 and207 * pending_reboot attributes208 */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 const 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 checks265 * @dest: Where to copy the string to266 * @src: Where to copy the string from267 */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 can276 * be empty so check only for too long buffers and log error277 */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 instance284 * @instance_id: WMI instance ID285 * @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 return289 */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_string302 * @guid_string: WMI GUID (in string form)303 */304int get_instance_count(const char *guid_string)305{306 int ret;307 308 ret = wmi_instance_count(guid_string);309 if (ret < 0)310 return 0;311 312 return ret;313}314 315/**316 * alloc_attributes_data() - Allocate attributes data for a particular type317 * @attr_type: Attribute type to allocate318 */319static int alloc_attributes_data(int attr_type)320{321 int retval = 0;322 323 switch (attr_type) {324 case ENUM:325 retval = alloc_enum_data();326 break;327 case INT:328 retval = alloc_int_data();329 break;330 case STR:331 retval = alloc_str_data();332 break;333 case PO:334 retval = alloc_po_data();335 break;336 default:337 break;338 }339 340 return retval;341}342 343/**344 * destroy_attribute_objs() - Free a kset of kobjects345 * @kset: The kset to destroy346 *347 * Fress kobjects created for each attribute_name under attribute type kset348 */349static void destroy_attribute_objs(struct kset *kset)350{351 struct kobject *pos, *next;352 353 list_for_each_entry_safe(pos, next, &kset->list, entry) {354 kobject_put(pos);355 }356}357 358/**359 * release_attributes_data() - Clean-up all sysfs directories and files created360 */361static void release_attributes_data(void)362{363 mutex_lock(&wmi_priv.mutex);364 exit_enum_attributes();365 exit_int_attributes();366 exit_str_attributes();367 exit_po_attributes();368 if (wmi_priv.authentication_dir_kset) {369 destroy_attribute_objs(wmi_priv.authentication_dir_kset);370 kset_unregister(wmi_priv.authentication_dir_kset);371 wmi_priv.authentication_dir_kset = NULL;372 }373 if (wmi_priv.main_dir_kset) {374 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);375 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);376 destroy_attribute_objs(wmi_priv.main_dir_kset);377 kset_unregister(wmi_priv.main_dir_kset);378 wmi_priv.main_dir_kset = NULL;379 }380 mutex_unlock(&wmi_priv.mutex);381}382 383/**384 * init_bios_attributes() - Initialize all attributes for a type385 * @attr_type: The attribute type to initialize386 * @guid: The WMI GUID associated with this type to initialize387 *388 * Initialiaze all 4 types of attributes enumeration, integer, string and password object.389 * Populates each attrbute typ's respective properties under sysfs files390 */391static int init_bios_attributes(int attr_type, const char *guid)392{393 struct kobject *attr_name_kobj; //individual attribute names394 union acpi_object *obj = NULL;395 union acpi_object *elements;396 struct kobject *duplicate;397 struct kset *tmp_set;398 int min_elements;399 400 /* instance_id needs to be reset for each type GUID401 * also, instance IDs are unique within GUID but not across402 */403 int instance_id = 0;404 int retval = 0;405 406 retval = alloc_attributes_data(attr_type);407 if (retval)408 return retval;409 410 switch (attr_type) {411 case ENUM: min_elements = 8; break;412 case INT: min_elements = 9; break;413 case STR: min_elements = 8; break;414 case PO: min_elements = 4; break;415 default:416 pr_err("Error: Unknown attr_type: %d\n", attr_type);417 return -EINVAL;418 }419 420 /* 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;424 425 mutex_lock(&wmi_priv.mutex);426 while (obj) {427 if (obj->type != ACPI_TYPE_PACKAGE) {428 pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type);429 retval = -EIO;430 goto err_attr_init;431 }432 433 if (obj->package.count < min_elements) {434 pr_err("Error: ACPI-package does not have enough elements: %d < %d\n",435 obj->package.count, min_elements);436 goto nextobj;437 }438 439 elements = obj->package.elements;440 441 /* sanity checking */442 if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {443 pr_debug("incorrect element type\n");444 goto nextobj;445 }446 if (strlen(elements[ATTR_NAME].string.pointer) == 0) {447 pr_debug("empty attribute found\n");448 goto nextobj;449 }450 if (attr_type == PO)451 tmp_set = wmi_priv.authentication_dir_kset;452 else453 tmp_set = wmi_priv.main_dir_kset;454 455 duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);456 if (duplicate) {457 pr_debug("Duplicate attribute name found - %s\n",458 elements[ATTR_NAME].string.pointer);459 kobject_put(duplicate);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, "Alienware", NULL) &&525 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {526 pr_err("Unable to run on non-Dell system\n");527 return -ENODEV;528 }529 530 ret = init_bios_attr_set_interface();531 if (ret)532 return ret;533 534 ret = init_bios_attr_pass_interface();535 if (ret)536 goto err_exit_bios_attr_set_interface;537 538 if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {539 pr_debug("failed to find set or pass interface\n");540 ret = -ENODEV;541 goto err_exit_bios_attr_pass_interface;542 }543 544 ret = fw_attributes_class_get(&fw_attr_class);545 if (ret)546 goto err_exit_bios_attr_pass_interface;547 548 wmi_priv.class_dev = device_create(fw_attr_class, NULL, MKDEV(0, 0),549 NULL, "%s", DRIVER_NAME);550 if (IS_ERR(wmi_priv.class_dev)) {551 ret = PTR_ERR(wmi_priv.class_dev);552 goto err_unregister_class;553 }554 555 wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,556 &wmi_priv.class_dev->kobj);557 if (!wmi_priv.main_dir_kset) {558 ret = -ENOMEM;559 goto err_destroy_classdev;560 }561 562 wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,563 &wmi_priv.class_dev->kobj);564 if (!wmi_priv.authentication_dir_kset) {565 ret = -ENOMEM;566 goto err_release_attributes_data;567 }568 569 ret = create_attributes_level_sysfs_files();570 if (ret) {571 pr_debug("could not create reset BIOS attribute\n");572 goto err_release_attributes_data;573 }574 575 ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);576 if (ret) {577 pr_debug("failed to populate enumeration type attributes\n");578 goto err_release_attributes_data;579 }580 581 ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);582 if (ret) {583 pr_debug("failed to populate integer type attributes\n");584 goto err_release_attributes_data;585 }586 587 ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);588 if (ret) {589 pr_debug("failed to populate string type attributes\n");590 goto err_release_attributes_data;591 }592 593 ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);594 if (ret) {595 pr_debug("failed to populate pass object type attributes\n");596 goto err_release_attributes_data;597 }598 599 return 0;600 601err_release_attributes_data:602 release_attributes_data();603 604err_destroy_classdev:605 device_destroy(fw_attr_class, MKDEV(0, 0));606 607err_unregister_class:608 fw_attributes_class_put();609 610err_exit_bios_attr_pass_interface:611 exit_bios_attr_pass_interface();612 613err_exit_bios_attr_set_interface:614 exit_bios_attr_set_interface();615 616 return ret;617}618 619static void __exit sysman_exit(void)620{621 release_attributes_data();622 device_destroy(fw_attr_class, MKDEV(0, 0));623 fw_attributes_class_put();624 exit_bios_attr_set_interface();625 exit_bios_attr_pass_interface();626}627 628module_init(sysman_init);629module_exit(sysman_exit);630 631MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");632MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");633MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");634MODULE_DESCRIPTION("Dell platform setting control interface");635MODULE_LICENSE("GPL");636