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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Common functions for kernel modules using Dell SMBIOS4 *5 * Copyright (c) Red Hat <mjg@redhat.com>6 * Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>7 * Copyright (c) 2014 Pali Rohár <pali@kernel.org>8 *9 * Based on documentation in the libsmbios package:10 * Copyright (C) 2005-2014 Dell Inc.11 */12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt13 14#include <linux/container_of.h>15#include <linux/kernel.h>16#include <linux/module.h>17#include <linux/capability.h>18#include <linux/dmi.h>19#include <linux/err.h>20#include <linux/mutex.h>21#include <linux/platform_device.h>22#include <linux/slab.h>23#include "dell-smbios.h"24 25static u32 da_supported_commands;26static int da_num_tokens;27static struct platform_device *platform_device;28static struct calling_interface_token *da_tokens;29static struct token_sysfs_data *token_entries;30static struct attribute **token_attrs;31static DEFINE_MUTEX(smbios_mutex);32 33struct token_sysfs_data {34 struct device_attribute location_attr;35 struct device_attribute value_attr;36 struct calling_interface_token *token;37};38 39struct smbios_device {40 struct list_head list;41 struct device *device;42 int (*call_fn)(struct calling_interface_buffer *arg);43};44 45struct smbios_call {46 u32 need_capability;47 int cmd_class;48 int cmd_select;49};50 51/* calls that are whitelisted for given capabilities */52static struct smbios_call call_whitelist[] = {53 /* generally tokens are allowed, but may be further filtered or54 * restricted by token blacklist or whitelist55 */56 {CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_STD},57 {CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_AC},58 {CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_BAT},59 {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_STD},60 {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_AC},61 {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_BAT},62 /* used by userspace: fwupdate */63 {CAP_SYS_ADMIN, CLASS_ADMIN_PROP, SELECT_ADMIN_PROP},64 /* used by userspace: fwupd */65 {CAP_SYS_ADMIN, CLASS_INFO, SELECT_DOCK},66 {CAP_SYS_ADMIN, CLASS_FLASH_INTERFACE, SELECT_FLASH_INTERFACE},67};68 69/* calls that are explicitly blacklisted */70static struct smbios_call call_blacklist[] = {71 {0x0000, 1, 7}, /* manufacturing use */72 {0x0000, 6, 5}, /* manufacturing use */73 {0x0000, 11, 3}, /* write once */74 {0x0000, 11, 7}, /* write once */75 {0x0000, 11, 11}, /* write once */76 {0x0000, 19, -1}, /* diagnostics */77 /* handled by kernel: dell-laptop */78 {0x0000, CLASS_INFO, SELECT_RFKILL},79 {0x0000, CLASS_KBD_BACKLIGHT, SELECT_KBD_BACKLIGHT},80 {0x0000, CLASS_INFO, SELECT_THERMAL_MANAGEMENT},81};82 83struct token_range {84 u32 need_capability;85 u16 min;86 u16 max;87};88 89/* tokens that are whitelisted for given capabilities */90static struct token_range token_whitelist[] = {91 /* used by userspace: fwupdate */92 {CAP_SYS_ADMIN, CAPSULE_EN_TOKEN, CAPSULE_DIS_TOKEN},93 /* can indicate to userspace that WMI is needed */94 {0x0000, WSMT_EN_TOKEN, WSMT_DIS_TOKEN}95};96 97/* tokens that are explicitly blacklisted */98static struct token_range token_blacklist[] = {99 {0x0000, 0x0058, 0x0059}, /* ME use */100 {0x0000, 0x00CD, 0x00D0}, /* raid shadow copy */101 {0x0000, 0x013A, 0x01FF}, /* sata shadow copy */102 {0x0000, 0x0175, 0x0176}, /* write once */103 {0x0000, 0x0195, 0x0197}, /* diagnostics */104 {0x0000, 0x01DC, 0x01DD}, /* manufacturing use */105 {0x0000, 0x027D, 0x0284}, /* diagnostics */106 {0x0000, 0x02E3, 0x02E3}, /* manufacturing use */107 {0x0000, 0x02FF, 0x02FF}, /* manufacturing use */108 {0x0000, 0x0300, 0x0302}, /* manufacturing use */109 {0x0000, 0x0325, 0x0326}, /* manufacturing use */110 {0x0000, 0x0332, 0x0335}, /* fan control */111 {0x0000, 0x0350, 0x0350}, /* manufacturing use */112 {0x0000, 0x0363, 0x0363}, /* manufacturing use */113 {0x0000, 0x0368, 0x0368}, /* manufacturing use */114 {0x0000, 0x03F6, 0x03F7}, /* manufacturing use */115 {0x0000, 0x049E, 0x049F}, /* manufacturing use */116 {0x0000, 0x04A0, 0x04A3}, /* disagnostics */117 {0x0000, 0x04E6, 0x04E7}, /* manufacturing use */118 {0x0000, 0x4000, 0x7FFF}, /* internal BIOS use */119 {0x0000, 0x9000, 0x9001}, /* internal BIOS use */120 {0x0000, 0xA000, 0xBFFF}, /* write only */121 {0x0000, 0xEFF0, 0xEFFF}, /* internal BIOS use */122 /* handled by kernel: dell-laptop */123 {0x0000, BRIGHTNESS_TOKEN, BRIGHTNESS_TOKEN},124 {0x0000, KBD_LED_OFF_TOKEN, KBD_LED_AUTO_TOKEN},125 {0x0000, KBD_LED_AC_TOKEN, KBD_LED_AC_TOKEN},126 {0x0000, KBD_LED_AUTO_25_TOKEN, KBD_LED_AUTO_75_TOKEN},127 {0x0000, KBD_LED_AUTO_100_TOKEN, KBD_LED_AUTO_100_TOKEN},128 {0x0000, GLOBAL_MIC_MUTE_ENABLE, GLOBAL_MIC_MUTE_DISABLE},129};130 131static LIST_HEAD(smbios_device_list);132 133int dell_smbios_error(int value)134{135 switch (value) {136 case 0: /* Completed successfully */137 return 0;138 case -1: /* Completed with error */139 return -EIO;140 case -2: /* Function not supported */141 return -ENXIO;142 default: /* Unknown error */143 return -EINVAL;144 }145}146EXPORT_SYMBOL_GPL(dell_smbios_error);147 148int dell_smbios_register_device(struct device *d, void *call_fn)149{150 struct smbios_device *priv;151 152 priv = devm_kzalloc(d, sizeof(struct smbios_device), GFP_KERNEL);153 if (!priv)154 return -ENOMEM;155 get_device(d);156 priv->device = d;157 priv->call_fn = call_fn;158 mutex_lock(&smbios_mutex);159 list_add_tail(&priv->list, &smbios_device_list);160 mutex_unlock(&smbios_mutex);161 dev_dbg(d, "Added device: %s\n", d->driver->name);162 return 0;163}164EXPORT_SYMBOL_GPL(dell_smbios_register_device);165 166void dell_smbios_unregister_device(struct device *d)167{168 struct smbios_device *priv;169 170 mutex_lock(&smbios_mutex);171 list_for_each_entry(priv, &smbios_device_list, list) {172 if (priv->device == d) {173 list_del(&priv->list);174 put_device(d);175 break;176 }177 }178 mutex_unlock(&smbios_mutex);179 dev_dbg(d, "Remove device: %s\n", d->driver->name);180}181EXPORT_SYMBOL_GPL(dell_smbios_unregister_device);182 183int dell_smbios_call_filter(struct device *d,184 struct calling_interface_buffer *buffer)185{186 u16 t = 0;187 int i;188 189 /* can't make calls over 30 */190 if (buffer->cmd_class > 30) {191 dev_dbg(d, "class too big: %u\n", buffer->cmd_class);192 return -EINVAL;193 }194 195 /* supported calls on the particular system */196 if (!(da_supported_commands & (1 << buffer->cmd_class))) {197 dev_dbg(d, "invalid command, supported commands: 0x%8x\n",198 da_supported_commands);199 return -EINVAL;200 }201 202 /* match against call blacklist */203 for (i = 0; i < ARRAY_SIZE(call_blacklist); i++) {204 if (buffer->cmd_class != call_blacklist[i].cmd_class)205 continue;206 if (buffer->cmd_select != call_blacklist[i].cmd_select &&207 call_blacklist[i].cmd_select != -1)208 continue;209 dev_dbg(d, "blacklisted command: %u/%u\n",210 buffer->cmd_class, buffer->cmd_select);211 return -EINVAL;212 }213 214 /* if a token call, find token ID */215 216 if ((buffer->cmd_class == CLASS_TOKEN_READ ||217 buffer->cmd_class == CLASS_TOKEN_WRITE) &&218 buffer->cmd_select < 3) {219 /* tokens enabled ? */220 if (!da_tokens) {221 dev_dbg(d, "no token support on this system\n");222 return -EINVAL;223 }224 225 /* find the matching token ID */226 for (i = 0; i < da_num_tokens; i++) {227 if (da_tokens[i].location != buffer->input[0])228 continue;229 t = da_tokens[i].tokenID;230 break;231 }232 233 /* token call; but token didn't exist */234 if (!t) {235 dev_dbg(d, "token at location %04x doesn't exist\n",236 buffer->input[0]);237 return -EINVAL;238 }239 240 /* match against token blacklist */241 for (i = 0; i < ARRAY_SIZE(token_blacklist); i++) {242 if (!token_blacklist[i].min || !token_blacklist[i].max)243 continue;244 if (t >= token_blacklist[i].min &&245 t <= token_blacklist[i].max)246 return -EINVAL;247 }248 249 /* match against token whitelist */250 for (i = 0; i < ARRAY_SIZE(token_whitelist); i++) {251 if (!token_whitelist[i].min || !token_whitelist[i].max)252 continue;253 if (t < token_whitelist[i].min ||254 t > token_whitelist[i].max)255 continue;256 if (!token_whitelist[i].need_capability ||257 capable(token_whitelist[i].need_capability)) {258 dev_dbg(d, "whitelisted token: %x\n", t);259 return 0;260 }261 262 }263 }264 /* match against call whitelist */265 for (i = 0; i < ARRAY_SIZE(call_whitelist); i++) {266 if (buffer->cmd_class != call_whitelist[i].cmd_class)267 continue;268 if (buffer->cmd_select != call_whitelist[i].cmd_select)269 continue;270 if (!call_whitelist[i].need_capability ||271 capable(call_whitelist[i].need_capability)) {272 dev_dbg(d, "whitelisted capable command: %u/%u\n",273 buffer->cmd_class, buffer->cmd_select);274 return 0;275 }276 dev_dbg(d, "missing capability %d for %u/%u\n",277 call_whitelist[i].need_capability,278 buffer->cmd_class, buffer->cmd_select);279 280 }281 282 /* not in a whitelist, only allow processes with capabilities */283 if (capable(CAP_SYS_RAWIO)) {284 dev_dbg(d, "Allowing %u/%u due to CAP_SYS_RAWIO\n",285 buffer->cmd_class, buffer->cmd_select);286 return 0;287 }288 289 return -EACCES;290}291EXPORT_SYMBOL_GPL(dell_smbios_call_filter);292 293int dell_smbios_call(struct calling_interface_buffer *buffer)294{295 int (*call_fn)(struct calling_interface_buffer *) = NULL;296 struct device *selected_dev = NULL;297 struct smbios_device *priv;298 int ret;299 300 mutex_lock(&smbios_mutex);301 list_for_each_entry(priv, &smbios_device_list, list) {302 if (!selected_dev || priv->device->id >= selected_dev->id) {303 dev_dbg(priv->device, "Trying device ID: %d\n",304 priv->device->id);305 call_fn = priv->call_fn;306 selected_dev = priv->device;307 }308 }309 310 if (!selected_dev) {311 ret = -ENODEV;312 pr_err("No dell-smbios drivers are loaded\n");313 goto out_smbios_call;314 }315 316 ret = call_fn(buffer);317 318out_smbios_call:319 mutex_unlock(&smbios_mutex);320 return ret;321}322EXPORT_SYMBOL_GPL(dell_smbios_call);323 324void dell_fill_request(struct calling_interface_buffer *buffer,325 u32 arg0, u32 arg1, u32 arg2, u32 arg3)326{327 memset(buffer, 0, sizeof(struct calling_interface_buffer));328 buffer->input[0] = arg0;329 buffer->input[1] = arg1;330 buffer->input[2] = arg2;331 buffer->input[3] = arg3;332}333EXPORT_SYMBOL_GPL(dell_fill_request);334 335int dell_send_request(struct calling_interface_buffer *buffer,336 u16 class, u16 select)337{338 int ret;339 340 buffer->cmd_class = class;341 buffer->cmd_select = select;342 ret = dell_smbios_call(buffer);343 if (ret != 0)344 return ret;345 return dell_smbios_error(buffer->output[0]);346}347EXPORT_SYMBOL_GPL(dell_send_request);348 349struct calling_interface_token *dell_smbios_find_token(int tokenid)350{351 int i;352 353 if (!da_tokens)354 return NULL;355 356 for (i = 0; i < da_num_tokens; i++) {357 if (da_tokens[i].tokenID == tokenid)358 return &da_tokens[i];359 }360 361 return NULL;362}363EXPORT_SYMBOL_GPL(dell_smbios_find_token);364 365static BLOCKING_NOTIFIER_HEAD(dell_laptop_chain_head);366 367int dell_laptop_register_notifier(struct notifier_block *nb)368{369 return blocking_notifier_chain_register(&dell_laptop_chain_head, nb);370}371EXPORT_SYMBOL_GPL(dell_laptop_register_notifier);372 373int dell_laptop_unregister_notifier(struct notifier_block *nb)374{375 return blocking_notifier_chain_unregister(&dell_laptop_chain_head, nb);376}377EXPORT_SYMBOL_GPL(dell_laptop_unregister_notifier);378 379void dell_laptop_call_notifier(unsigned long action, void *data)380{381 blocking_notifier_call_chain(&dell_laptop_chain_head, action, data);382}383EXPORT_SYMBOL_GPL(dell_laptop_call_notifier);384 385bool dell_smbios_class_is_supported(u16 class)386{387 /* Classes over 30 always unsupported */388 if (class > 30)389 return false;390 return da_supported_commands & (1 << class);391}392EXPORT_SYMBOL_GPL(dell_smbios_class_is_supported);393 394static void __init parse_da_table(const struct dmi_header *dm)395{396 /* Final token is a terminator, so we don't want to copy it */397 int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;398 struct calling_interface_token *new_da_tokens;399 struct calling_interface_structure *table =400 container_of(dm, struct calling_interface_structure, header);401 402 /*403 * 4 bytes of table header, plus 7 bytes of Dell header404 * plus at least 6 bytes of entry405 */406 407 if (dm->length < 17)408 return;409 410 da_supported_commands = table->supportedCmds;411 412 new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *413 sizeof(struct calling_interface_token),414 GFP_KERNEL);415 416 if (!new_da_tokens)417 return;418 da_tokens = new_da_tokens;419 420 memcpy(da_tokens+da_num_tokens, table->tokens,421 sizeof(struct calling_interface_token) * tokens);422 423 da_num_tokens += tokens;424}425 426static void zero_duplicates(struct device *dev)427{428 int i, j;429 430 for (i = 0; i < da_num_tokens; i++) {431 if (da_tokens[i].tokenID == 0)432 continue;433 for (j = i+1; j < da_num_tokens; j++) {434 if (da_tokens[j].tokenID == 0)435 continue;436 if (da_tokens[i].tokenID == da_tokens[j].tokenID) {437 dev_dbg(dev, "Zeroing dup token ID %x(%x/%x)\n",438 da_tokens[j].tokenID,439 da_tokens[j].location,440 da_tokens[j].value);441 da_tokens[j].tokenID = 0;442 }443 }444 }445}446 447static void __init find_tokens(const struct dmi_header *dm, void *dummy)448{449 switch (dm->type) {450 case 0xd4: /* Indexed IO */451 case 0xd5: /* Protected Area Type 1 */452 case 0xd6: /* Protected Area Type 2 */453 break;454 case 0xda: /* Calling interface */455 parse_da_table(dm);456 break;457 }458}459 460static ssize_t location_show(struct device *dev,461 struct device_attribute *attr, char *buf)462{463 struct token_sysfs_data *data = container_of(attr, struct token_sysfs_data, location_attr);464 465 if (!capable(CAP_SYS_ADMIN))466 return -EPERM;467 468 return sysfs_emit(buf, "%08x", data->token->location);469}470 471static ssize_t value_show(struct device *dev,472 struct device_attribute *attr, char *buf)473{474 struct token_sysfs_data *data = container_of(attr, struct token_sysfs_data, value_attr);475 476 if (!capable(CAP_SYS_ADMIN))477 return -EPERM;478 479 return sysfs_emit(buf, "%08x", data->token->value);480}481 482static struct attribute_group smbios_attribute_group = {483 .name = "tokens"484};485 486static struct platform_driver platform_driver = {487 .driver = {488 .name = "dell-smbios",489 },490};491 492static int build_tokens_sysfs(struct platform_device *dev)493{494 char *location_name;495 char *value_name;496 int ret;497 int i, j;498 499 token_entries = kcalloc(da_num_tokens, sizeof(*token_entries), GFP_KERNEL);500 if (!token_entries)501 return -ENOMEM;502 503 /* need to store both location and value + terminator*/504 token_attrs = kcalloc((2 * da_num_tokens) + 1, sizeof(*token_attrs), GFP_KERNEL);505 if (!token_attrs)506 goto out_allocate_attrs;507 508 for (i = 0, j = 0; i < da_num_tokens; i++) {509 /* skip empty */510 if (da_tokens[i].tokenID == 0)511 continue;512 513 token_entries[i].token = &da_tokens[i];514 515 /* add location */516 location_name = kasprintf(GFP_KERNEL, "%04x_location",517 da_tokens[i].tokenID);518 if (location_name == NULL)519 goto out_unwind_strings;520 521 sysfs_attr_init(&token_entries[i].location_attr.attr);522 token_entries[i].location_attr.attr.name = location_name;523 token_entries[i].location_attr.attr.mode = 0444;524 token_entries[i].location_attr.show = location_show;525 token_attrs[j++] = &token_entries[i].location_attr.attr;526 527 /* add value */528 value_name = kasprintf(GFP_KERNEL, "%04x_value",529 da_tokens[i].tokenID);530 if (!value_name) {531 kfree(location_name);532 goto out_unwind_strings;533 }534 535 sysfs_attr_init(&token_entries[i].value_attr.attr);536 token_entries[i].value_attr.attr.name = value_name;537 token_entries[i].value_attr.attr.mode = 0444;538 token_entries[i].value_attr.show = value_show;539 token_attrs[j++] = &token_entries[i].value_attr.attr;540 }541 smbios_attribute_group.attrs = token_attrs;542 543 ret = sysfs_create_group(&dev->dev.kobj, &smbios_attribute_group);544 if (ret)545 goto out_unwind_strings;546 return 0;547 548out_unwind_strings:549 while (i--) {550 kfree(token_entries[i].location_attr.attr.name);551 kfree(token_entries[i].value_attr.attr.name);552 }553 kfree(token_attrs);554out_allocate_attrs:555 kfree(token_entries);556 557 return -ENOMEM;558}559 560static void free_group(struct platform_device *pdev)561{562 int i;563 564 sysfs_remove_group(&pdev->dev.kobj,565 &smbios_attribute_group);566 for (i = 0; i < da_num_tokens; i++) {567 kfree(token_entries[i].location_attr.attr.name);568 kfree(token_entries[i].value_attr.attr.name);569 }570 kfree(token_attrs);571 kfree(token_entries);572}573 574static int __init dell_smbios_init(void)575{576 int ret, wmi, smm;577 578 if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&579 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Alienware", NULL) &&580 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {581 pr_err("Unable to run on non-Dell system\n");582 return -ENODEV;583 }584 585 dmi_walk(find_tokens, NULL);586 587 ret = platform_driver_register(&platform_driver);588 if (ret)589 goto fail_platform_driver;590 591 platform_device = platform_device_alloc("dell-smbios", 0);592 if (!platform_device) {593 ret = -ENOMEM;594 goto fail_platform_device_alloc;595 }596 ret = platform_device_add(platform_device);597 if (ret)598 goto fail_platform_device_add;599 600 /* register backends */601 wmi = init_dell_smbios_wmi();602 if (wmi)603 pr_debug("Failed to initialize WMI backend: %d\n", wmi);604 smm = init_dell_smbios_smm();605 if (smm)606 pr_debug("Failed to initialize SMM backend: %d\n", smm);607 if (wmi && smm) {608 pr_err("No SMBIOS backends available (wmi: %d, smm: %d)\n",609 wmi, smm);610 ret = -ENODEV;611 goto fail_create_group;612 }613 614 if (da_tokens) {615 /* duplicate tokens will cause problems building sysfs files */616 zero_duplicates(&platform_device->dev);617 618 ret = build_tokens_sysfs(platform_device);619 if (ret)620 goto fail_sysfs;621 }622 623 return 0;624 625fail_sysfs:626 if (!wmi)627 exit_dell_smbios_wmi();628 if (!smm)629 exit_dell_smbios_smm();630 631fail_create_group:632 platform_device_del(platform_device);633 634fail_platform_device_add:635 platform_device_put(platform_device);636 637fail_platform_device_alloc:638 platform_driver_unregister(&platform_driver);639 640fail_platform_driver:641 kfree(da_tokens);642 return ret;643}644 645static void __exit dell_smbios_exit(void)646{647 exit_dell_smbios_wmi();648 exit_dell_smbios_smm();649 mutex_lock(&smbios_mutex);650 if (platform_device) {651 if (da_tokens)652 free_group(platform_device);653 platform_device_unregister(platform_device);654 platform_driver_unregister(&platform_driver);655 }656 kfree(da_tokens);657 mutex_unlock(&smbios_mutex);658}659 660module_init(dell_smbios_init);661module_exit(dell_smbios_exit);662 663MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");664MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");665MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");666MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");667MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");668MODULE_LICENSE("GPL");669