root/drivers/char/tpm/tpm-chip.c

DEFINITIONS

1. tpm_request_locality
2. tpm_relinquish_locality
3. tpm_cmd_ready
4. tpm_go_idle
5. tpm_clk_enable
6. tpm_clk_disable
7. tpm_chip_start
8. tpm_chip_stop
9. tpm_try_get_ops
10. tpm_put_ops
11. tpm_default_chip
12. tpm_find_get_ops
13. tpm_dev_release
14. tpm_devs_release
15. tpm_class_shutdown
16. tpm_chip_alloc
17. tpmm_chip_alloc
18. tpm_add_char_device
19. tpm_del_char_device
20. tpm_del_legacy_sysfs
21. tpm_add_legacy_sysfs
22. tpm_hwrng_read
23. tpm_add_hwrng
24. tpm_get_pcr_allocation
25. tpm_chip_register
26. tpm_chip_unregister

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2004 IBM Corporation
   4  * Copyright (C) 2014 Intel Corporation
   5  *
   6  * Authors:
   7  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
   8  * Leendert van Doorn <leendert@watson.ibm.com>
   9  * Dave Safford <safford@watson.ibm.com>
  10  * Reiner Sailer <sailer@watson.ibm.com>
  11  * Kylene Hall <kjhall@us.ibm.com>
  12  *
  13  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  14  *
  15  * TPM chip management routines.
  16  */
  17 
  18 #include <linux/poll.h>
  19 #include <linux/slab.h>
  20 #include <linux/mutex.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/freezer.h>
  23 #include <linux/major.h>
  24 #include <linux/tpm_eventlog.h>
  25 #include <linux/hw_random.h>
  26 #include "tpm.h"
  27 
  28 DEFINE_IDR(dev_nums_idr);
  29 static DEFINE_MUTEX(idr_lock);
  30 
  31 struct class *tpm_class;
  32 struct class *tpmrm_class;
  33 dev_t tpm_devt;
  34 
  35 static int tpm_request_locality(struct tpm_chip *chip)
  36 {
  37         int rc;
  38 
  39         if (!chip->ops->request_locality)
  40                 return 0;
  41 
  42         rc = chip->ops->request_locality(chip, 0);
  43         if (rc < 0)
  44                 return rc;
  45 
  46         chip->locality = rc;
  47         return 0;
  48 }
  49 
  50 static void tpm_relinquish_locality(struct tpm_chip *chip)
  51 {
  52         int rc;
  53 
  54         if (!chip->ops->relinquish_locality)
  55                 return;
  56 
  57         rc = chip->ops->relinquish_locality(chip, chip->locality);
  58         if (rc)
  59                 dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
  60 
  61         chip->locality = -1;
  62 }
  63 
  64 static int tpm_cmd_ready(struct tpm_chip *chip)
  65 {
  66         if (!chip->ops->cmd_ready)
  67                 return 0;
  68 
  69         return chip->ops->cmd_ready(chip);
  70 }
  71 
  72 static int tpm_go_idle(struct tpm_chip *chip)
  73 {
  74         if (!chip->ops->go_idle)
  75                 return 0;
  76 
  77         return chip->ops->go_idle(chip);
  78 }
  79 
  80 static void tpm_clk_enable(struct tpm_chip *chip)
  81 {
  82         if (chip->ops->clk_enable)
  83                 chip->ops->clk_enable(chip, true);
  84 }
  85 
  86 static void tpm_clk_disable(struct tpm_chip *chip)
  87 {
  88         if (chip->ops->clk_enable)
  89                 chip->ops->clk_enable(chip, false);
  90 }
  91 
  92 /**
  93  * tpm_chip_start() - power on the TPM
  94  * @chip:       a TPM chip to use
  95  *
  96  * Return:
  97  * * The response length        - OK
  98  * * -errno                     - A system error
  99  */
 100 int tpm_chip_start(struct tpm_chip *chip)
 101 {
 102         int ret;
 103 
 104         tpm_clk_enable(chip);
 105 
 106         if (chip->locality == -1) {
 107                 ret = tpm_request_locality(chip);
 108                 if (ret) {
 109                         tpm_clk_disable(chip);
 110                         return ret;
 111                 }
 112         }
 113 
 114         ret = tpm_cmd_ready(chip);
 115         if (ret) {
 116                 tpm_relinquish_locality(chip);
 117                 tpm_clk_disable(chip);
 118                 return ret;
 119         }
 120 
 121         return 0;
 122 }
 123 EXPORT_SYMBOL_GPL(tpm_chip_start);
 124 
 125 /**
 126  * tpm_chip_stop() - power off the TPM
 127  * @chip:       a TPM chip to use
 128  *
 129  * Return:
 130  * * The response length        - OK
 131  * * -errno                     - A system error
 132  */
 133 void tpm_chip_stop(struct tpm_chip *chip)
 134 {
 135         tpm_go_idle(chip);
 136         tpm_relinquish_locality(chip);
 137         tpm_clk_disable(chip);
 138 }
 139 EXPORT_SYMBOL_GPL(tpm_chip_stop);
 140 
 141 /**
 142  * tpm_try_get_ops() - Get a ref to the tpm_chip
 143  * @chip: Chip to ref
 144  *
 145  * The caller must already have some kind of locking to ensure that chip is
 146  * valid. This function will lock the chip so that the ops member can be
 147  * accessed safely. The locking prevents tpm_chip_unregister from
 148  * completing, so it should not be held for long periods.
 149  *
 150  * Returns -ERRNO if the chip could not be got.
 151  */
 152 int tpm_try_get_ops(struct tpm_chip *chip)
 153 {
 154         int rc = -EIO;
 155 
 156         get_device(&chip->dev);
 157 
 158         down_read(&chip->ops_sem);
 159         if (!chip->ops)
 160                 goto out_ops;
 161 
 162         mutex_lock(&chip->tpm_mutex);
 163         rc = tpm_chip_start(chip);
 164         if (rc)
 165                 goto out_lock;
 166 
 167         return 0;
 168 out_lock:
 169         mutex_unlock(&chip->tpm_mutex);
 170 out_ops:
 171         up_read(&chip->ops_sem);
 172         put_device(&chip->dev);
 173         return rc;
 174 }
 175 EXPORT_SYMBOL_GPL(tpm_try_get_ops);
 176 
 177 /**
 178  * tpm_put_ops() - Release a ref to the tpm_chip
 179  * @chip: Chip to put
 180  *
 181  * This is the opposite pair to tpm_try_get_ops(). After this returns chip may
 182  * be kfree'd.
 183  */
 184 void tpm_put_ops(struct tpm_chip *chip)
 185 {
 186         tpm_chip_stop(chip);
 187         mutex_unlock(&chip->tpm_mutex);
 188         up_read(&chip->ops_sem);
 189         put_device(&chip->dev);
 190 }
 191 EXPORT_SYMBOL_GPL(tpm_put_ops);
 192 
 193 /**
 194  * tpm_default_chip() - find a TPM chip and get a reference to it
 195  */
 196 struct tpm_chip *tpm_default_chip(void)
 197 {
 198         struct tpm_chip *chip, *res = NULL;
 199         int chip_num = 0;
 200         int chip_prev;
 201 
 202         mutex_lock(&idr_lock);
 203 
 204         do {
 205                 chip_prev = chip_num;
 206                 chip = idr_get_next(&dev_nums_idr, &chip_num);
 207                 if (chip) {
 208                         get_device(&chip->dev);
 209                         res = chip;
 210                         break;
 211                 }
 212         } while (chip_prev != chip_num);
 213 
 214         mutex_unlock(&idr_lock);
 215 
 216         return res;
 217 }
 218 EXPORT_SYMBOL_GPL(tpm_default_chip);
 219 
 220 /**
 221  * tpm_find_get_ops() - find and reserve a TPM chip
 222  * @chip:       a &struct tpm_chip instance, %NULL for the default chip
 223  *
 224  * Finds a TPM chip and reserves its class device and operations. The chip must
 225  * be released with tpm_put_ops() after use.
 226  * This function is for internal use only. It supports existing TPM callers
 227  * by accepting NULL, but those callers should be converted to pass in a chip
 228  * directly.
 229  *
 230  * Return:
 231  * A reserved &struct tpm_chip instance.
 232  * %NULL if a chip is not found.
 233  * %NULL if the chip is not available.
 234  */
 235 struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip)
 236 {
 237         int rc;
 238 
 239         if (chip) {
 240                 if (!tpm_try_get_ops(chip))
 241                         return chip;
 242                 return NULL;
 243         }
 244 
 245         chip = tpm_default_chip();
 246         if (!chip)
 247                 return NULL;
 248         rc = tpm_try_get_ops(chip);
 249         /* release additional reference we got from tpm_default_chip() */
 250         put_device(&chip->dev);
 251         if (rc)
 252                 return NULL;
 253         return chip;
 254 }
 255 
 256 /**
 257  * tpm_dev_release() - free chip memory and the device number
 258  * @dev: the character device for the TPM chip
 259  *
 260  * This is used as the release function for the character device.
 261  */
 262 static void tpm_dev_release(struct device *dev)
 263 {
 264         struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
 265 
 266         mutex_lock(&idr_lock);
 267         idr_remove(&dev_nums_idr, chip->dev_num);
 268         mutex_unlock(&idr_lock);
 269 
 270         kfree(chip->log.bios_event_log);
 271         kfree(chip->work_space.context_buf);
 272         kfree(chip->work_space.session_buf);
 273         kfree(chip->allocated_banks);
 274         kfree(chip);
 275 }
 276 
 277 static void tpm_devs_release(struct device *dev)
 278 {
 279         struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
 280 
 281         /* release the master device reference */
 282         put_device(&chip->dev);
 283 }
 284 
 285 /**
 286  * tpm_class_shutdown() - prepare the TPM device for loss of power.
 287  * @dev: device to which the chip is associated.
 288  *
 289  * Issues a TPM2_Shutdown command prior to loss of power, as required by the
 290  * TPM 2.0 spec. Then, calls bus- and device- specific shutdown code.
 291  *
 292  * Return: always 0 (i.e. success)
 293  */
 294 static int tpm_class_shutdown(struct device *dev)
 295 {
 296         struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
 297 
 298         down_write(&chip->ops_sem);
 299         if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 300                 if (!tpm_chip_start(chip)) {
 301                         tpm2_shutdown(chip, TPM2_SU_CLEAR);
 302                         tpm_chip_stop(chip);
 303                 }
 304         }
 305         chip->ops = NULL;
 306         up_write(&chip->ops_sem);
 307 
 308         return 0;
 309 }
 310 
 311 /**
 312  * tpm_chip_alloc() - allocate a new struct tpm_chip instance
 313  * @pdev: device to which the chip is associated
 314  *        At this point pdev mst be initialized, but does not have to
 315  *        be registered
 316  * @ops: struct tpm_class_ops instance
 317  *
 318  * Allocates a new struct tpm_chip instance and assigns a free
 319  * device number for it. Must be paired with put_device(&chip->dev).
 320  */
 321 struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 322                                 const struct tpm_class_ops *ops)
 323 {
 324         struct tpm_chip *chip;
 325         int rc;
 326 
 327         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 328         if (chip == NULL)
 329                 return ERR_PTR(-ENOMEM);
 330 
 331         mutex_init(&chip->tpm_mutex);
 332         init_rwsem(&chip->ops_sem);
 333 
 334         chip->ops = ops;
 335 
 336         mutex_lock(&idr_lock);
 337         rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
 338         mutex_unlock(&idr_lock);
 339         if (rc < 0) {
 340                 dev_err(pdev, "No available tpm device numbers\n");
 341                 kfree(chip);
 342                 return ERR_PTR(rc);
 343         }
 344         chip->dev_num = rc;
 345 
 346         device_initialize(&chip->dev);
 347         device_initialize(&chip->devs);
 348 
 349         chip->dev.class = tpm_class;
 350         chip->dev.class->shutdown_pre = tpm_class_shutdown;
 351         chip->dev.release = tpm_dev_release;
 352         chip->dev.parent = pdev;
 353         chip->dev.groups = chip->groups;
 354 
 355         chip->devs.parent = pdev;
 356         chip->devs.class = tpmrm_class;
 357         chip->devs.release = tpm_devs_release;
 358         /* get extra reference on main device to hold on
 359          * behalf of devs.  This holds the chip structure
 360          * while cdevs is in use.  The corresponding put
 361          * is in the tpm_devs_release (TPM2 only)
 362          */
 363         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 364                 get_device(&chip->dev);
 365 
 366         if (chip->dev_num == 0)
 367                 chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
 368         else
 369                 chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
 370 
 371         chip->devs.devt =
 372                 MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
 373 
 374         rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
 375         if (rc)
 376                 goto out;
 377         rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
 378         if (rc)
 379                 goto out;
 380 
 381         if (!pdev)
 382                 chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
 383 
 384         cdev_init(&chip->cdev, &tpm_fops);
 385         cdev_init(&chip->cdevs, &tpmrm_fops);
 386         chip->cdev.owner = THIS_MODULE;
 387         chip->cdevs.owner = THIS_MODULE;
 388 
 389         chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 390         if (!chip->work_space.context_buf) {
 391                 rc = -ENOMEM;
 392                 goto out;
 393         }
 394         chip->work_space.session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 395         if (!chip->work_space.session_buf) {
 396                 rc = -ENOMEM;
 397                 goto out;
 398         }
 399 
 400         chip->locality = -1;
 401         return chip;
 402 
 403 out:
 404         put_device(&chip->devs);
 405         put_device(&chip->dev);
 406         return ERR_PTR(rc);
 407 }
 408 EXPORT_SYMBOL_GPL(tpm_chip_alloc);
 409 
 410 /**
 411  * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
 412  * @pdev: parent device to which the chip is associated
 413  * @ops: struct tpm_class_ops instance
 414  *
 415  * Same as tpm_chip_alloc except devm is used to do the put_device
 416  */
 417 struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
 418                                  const struct tpm_class_ops *ops)
 419 {
 420         struct tpm_chip *chip;
 421         int rc;
 422 
 423         chip = tpm_chip_alloc(pdev, ops);
 424         if (IS_ERR(chip))
 425                 return chip;
 426 
 427         rc = devm_add_action_or_reset(pdev,
 428                                       (void (*)(void *)) put_device,
 429                                       &chip->dev);
 430         if (rc)
 431                 return ERR_PTR(rc);
 432 
 433         dev_set_drvdata(pdev, chip);
 434 
 435         return chip;
 436 }
 437 EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
 438 
 439 static int tpm_add_char_device(struct tpm_chip *chip)
 440 {
 441         int rc;
 442 
 443         rc = cdev_device_add(&chip->cdev, &chip->dev);
 444         if (rc) {
 445                 dev_err(&chip->dev,
 446                         "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
 447                         dev_name(&chip->dev), MAJOR(chip->dev.devt),
 448                         MINOR(chip->dev.devt), rc);
 449                 return rc;
 450         }
 451 
 452         if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 453                 rc = cdev_device_add(&chip->cdevs, &chip->devs);
 454                 if (rc) {
 455                         dev_err(&chip->devs,
 456                                 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
 457                                 dev_name(&chip->devs), MAJOR(chip->devs.devt),
 458                                 MINOR(chip->devs.devt), rc);
 459                         return rc;
 460                 }
 461         }
 462 
 463         /* Make the chip available. */
 464         mutex_lock(&idr_lock);
 465         idr_replace(&dev_nums_idr, chip, chip->dev_num);
 466         mutex_unlock(&idr_lock);
 467 
 468         return rc;
 469 }
 470 
 471 static void tpm_del_char_device(struct tpm_chip *chip)
 472 {
 473         cdev_device_del(&chip->cdev, &chip->dev);
 474 
 475         /* Make the chip unavailable. */
 476         mutex_lock(&idr_lock);
 477         idr_replace(&dev_nums_idr, NULL, chip->dev_num);
 478         mutex_unlock(&idr_lock);
 479 
 480         /* Make the driver uncallable. */
 481         down_write(&chip->ops_sem);
 482         if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 483                 if (!tpm_chip_start(chip)) {
 484                         tpm2_shutdown(chip, TPM2_SU_CLEAR);
 485                         tpm_chip_stop(chip);
 486                 }
 487         }
 488         chip->ops = NULL;
 489         up_write(&chip->ops_sem);
 490 }
 491 
 492 static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
 493 {
 494         struct attribute **i;
 495 
 496         if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
 497                 return;
 498 
 499         sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
 500 
 501         for (i = chip->groups[0]->attrs; *i != NULL; ++i)
 502                 sysfs_remove_link(&chip->dev.parent->kobj, (*i)->name);
 503 }
 504 
 505 /* For compatibility with legacy sysfs paths we provide symlinks from the
 506  * parent dev directory to selected names within the tpm chip directory. Old
 507  * kernel versions created these files directly under the parent.
 508  */
 509 static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
 510 {
 511         struct attribute **i;
 512         int rc;
 513 
 514         if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
 515                 return 0;
 516 
 517         rc = __compat_only_sysfs_link_entry_to_kobj(
 518                     &chip->dev.parent->kobj, &chip->dev.kobj, "ppi");
 519         if (rc && rc != -ENOENT)
 520                 return rc;
 521 
 522         /* All the names from tpm-sysfs */
 523         for (i = chip->groups[0]->attrs; *i != NULL; ++i) {
 524                 rc = __compat_only_sysfs_link_entry_to_kobj(
 525                     &chip->dev.parent->kobj, &chip->dev.kobj, (*i)->name);
 526                 if (rc) {
 527                         tpm_del_legacy_sysfs(chip);
 528                         return rc;
 529                 }
 530         }
 531 
 532         return 0;
 533 }
 534 
 535 static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 536 {
 537         struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng);
 538 
 539         return tpm_get_random(chip, data, max);
 540 }
 541 
 542 static int tpm_add_hwrng(struct tpm_chip *chip)
 543 {
 544         if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
 545                 return 0;
 546 
 547         snprintf(chip->hwrng_name, sizeof(chip->hwrng_name),
 548                  "tpm-rng-%d", chip->dev_num);
 549         chip->hwrng.name = chip->hwrng_name;
 550         chip->hwrng.read = tpm_hwrng_read;
 551         return hwrng_register(&chip->hwrng);
 552 }
 553 
 554 static int tpm_get_pcr_allocation(struct tpm_chip *chip)
 555 {
 556         int rc;
 557 
 558         rc = (chip->flags & TPM_CHIP_FLAG_TPM2) ?
 559              tpm2_get_pcr_allocation(chip) :
 560              tpm1_get_pcr_allocation(chip);
 561 
 562         if (rc > 0)
 563                 return -ENODEV;
 564 
 565         return rc;
 566 }
 567 
 568 /*
 569  * tpm_chip_register() - create a character device for the TPM chip
 570  * @chip: TPM chip to use.
 571  *
 572  * Creates a character device for the TPM chip and adds sysfs attributes for
 573  * the device. As the last step this function adds the chip to the list of TPM
 574  * chips available for in-kernel use.
 575  *
 576  * This function should be only called after the chip initialization is
 577  * complete.
 578  */
 579 int tpm_chip_register(struct tpm_chip *chip)
 580 {
 581         int rc;
 582 
 583         rc = tpm_chip_start(chip);
 584         if (rc)
 585                 return rc;
 586         rc = tpm_auto_startup(chip);
 587         if (rc) {
 588                 tpm_chip_stop(chip);
 589                 return rc;
 590         }
 591 
 592         rc = tpm_get_pcr_allocation(chip);
 593         tpm_chip_stop(chip);
 594         if (rc)
 595                 return rc;
 596 
 597         tpm_sysfs_add_device(chip);
 598 
 599         tpm_bios_log_setup(chip);
 600 
 601         tpm_add_ppi(chip);
 602 
 603         rc = tpm_add_hwrng(chip);
 604         if (rc)
 605                 goto out_ppi;
 606 
 607         rc = tpm_add_char_device(chip);
 608         if (rc)
 609                 goto out_hwrng;
 610 
 611         rc = tpm_add_legacy_sysfs(chip);
 612         if (rc) {
 613                 tpm_chip_unregister(chip);
 614                 return rc;
 615         }
 616 
 617         return 0;
 618 
 619 out_hwrng:
 620         if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
 621                 hwrng_unregister(&chip->hwrng);
 622 out_ppi:
 623         tpm_bios_log_teardown(chip);
 624 
 625         return rc;
 626 }
 627 EXPORT_SYMBOL_GPL(tpm_chip_register);
 628 
 629 /*
 630  * tpm_chip_unregister() - release the TPM driver
 631  * @chip: TPM chip to use.
 632  *
 633  * Takes the chip first away from the list of available TPM chips and then
 634  * cleans up all the resources reserved by tpm_chip_register().
 635  *
 636  * Once this function returns the driver call backs in 'op's will not be
 637  * running and will no longer start.
 638  *
 639  * NOTE: This function should be only called before deinitializing chip
 640  * resources.
 641  */
 642 void tpm_chip_unregister(struct tpm_chip *chip)
 643 {
 644         tpm_del_legacy_sysfs(chip);
 645         if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
 646                 hwrng_unregister(&chip->hwrng);
 647         tpm_bios_log_teardown(chip);
 648         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 649                 cdev_device_del(&chip->cdevs, &chip->devs);
 650         tpm_del_char_device(chip);
 651 }
 652 EXPORT_SYMBOL_GPL(tpm_chip_unregister);