drivers/char/tpm/tpm_vtpm_proxy.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2015, 2016 IBM Corporation
   4  * Copyright (C) 2016 Intel Corporation
   5  *
   6  * Author: Stefan Berger <stefanb@us.ibm.com>
   7  *
   8  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
   9  *
  10  * Device driver for vTPM (vTPM proxy driver)
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/uaccess.h>
  16 #include <linux/wait.h>
  17 #include <linux/miscdevice.h>
  18 #include <linux/vtpm_proxy.h>
  19 #include <linux/file.h>
  20 #include <linux/anon_inodes.h>
  21 #include <linux/poll.h>
  22 #include <linux/compat.h>
  23
  24 #include "tpm.h"
  25
  26 #define VTPM_PROXY_REQ_COMPLETE_FLAG  BIT(0)
  27
  28 struct proxy_dev {
  29         struct tpm_chip *chip;
  30
  31         u32 flags;                   /* public API flags */
  32
  33         wait_queue_head_t wq;
  34
  35         struct mutex buf_lock;       /* protect buffer and flags */
  36
  37         long state;                  /* internal state */
  38 #define STATE_OPENED_FLAG        BIT(0)
  39 #define STATE_WAIT_RESPONSE_FLAG BIT(1)  /* waiting for emulator response */
  40 #define STATE_REGISTERED_FLAG    BIT(2)
  41 #define STATE_DRIVER_COMMAND     BIT(3)  /* sending a driver specific command */
  42
  43         size_t req_len;              /* length of queued TPM request */
  44         size_t resp_len;             /* length of queued TPM response */
  45         u8 buffer[TPM_BUFSIZE];      /* request/response buffer */
  46
  47         struct work_struct work;     /* task that retrieves TPM timeouts */
  48 };
  49
  50 /* all supported flags */
  51 #define VTPM_PROXY_FLAGS_ALL  (VTPM_PROXY_FLAG_TPM2)
  52
  53 static struct workqueue_struct *workqueue;
  54
  55 static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev);
  56
  57 /*
  58  * Functions related to 'server side'
  59  */
  60
  61 /**
  62  * vtpm_proxy_fops_read - Read TPM commands on 'server side'
  63  *
  64  * @filp: file pointer
  65  * @buf: read buffer
  66  * @count: number of bytes to read
  67  * @off: offset
  68  *
  69  * Return:
  70  *      Number of bytes read or negative error code
  71  */
  72 static ssize_t vtpm_proxy_fops_read(struct file *filp, char __user *buf,
  73                                     size_t count, loff_t *off)
  74 {
  75         struct proxy_dev *proxy_dev = filp->private_data;
  76         size_t len;
  77         int sig, rc;
  78
  79         sig = wait_event_interruptible(proxy_dev->wq,
  80                 proxy_dev->req_len != 0 ||
  81                 !(proxy_dev->state & STATE_OPENED_FLAG));
  82         if (sig)
  83                 return -EINTR;
  84
  85         mutex_lock(&proxy_dev->buf_lock);
  86
  87         if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
  88                 mutex_unlock(&proxy_dev->buf_lock);
  89                 return -EPIPE;
  90         }
  91
  92         len = proxy_dev->req_len;
  93
  94         if (count < len || len > sizeof(proxy_dev->buffer)) {
  95                 mutex_unlock(&proxy_dev->buf_lock);
  96                 pr_debug("Invalid size in recv: count=%zd, req_len=%zd\n",
  97                          count, len);
  98                 return -EIO;
  99         }
 100
 101         rc = copy_to_user(buf, proxy_dev->buffer, len);
 102         memset(proxy_dev->buffer, 0, len);
 103         proxy_dev->req_len = 0;
 104
 105         if (!rc)
 106                 proxy_dev->state |= STATE_WAIT_RESPONSE_FLAG;
 107
 108         mutex_unlock(&proxy_dev->buf_lock);
 109
 110         if (rc)
 111                 return -EFAULT;
 112
 113         return len;
 114 }
 115
 116 /**
 117  * vtpm_proxy_fops_write - Write TPM responses on 'server side'
 118  *
 119  * @filp: file pointer
 120  * @buf: write buffer
 121  * @count: number of bytes to write
 122  * @off: offset
 123  *
 124  * Return:
 125  *      Number of bytes read or negative error value
 126  */
 127 static ssize_t vtpm_proxy_fops_write(struct file *filp, const char __user *buf,
 128                                      size_t count, loff_t *off)
 129 {
 130         struct proxy_dev *proxy_dev = filp->private_data;
 131
 132         mutex_lock(&proxy_dev->buf_lock);
 133
 134         if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
 135                 mutex_unlock(&proxy_dev->buf_lock);
 136                 return -EPIPE;
 137         }
 138
 139         if (count > sizeof(proxy_dev->buffer) ||
 140             !(proxy_dev->state & STATE_WAIT_RESPONSE_FLAG)) {
 141                 mutex_unlock(&proxy_dev->buf_lock);
 142                 return -EIO;
 143         }
 144
 145         proxy_dev->state &= ~STATE_WAIT_RESPONSE_FLAG;
 146
 147         proxy_dev->req_len = 0;
 148
 149         if (copy_from_user(proxy_dev->buffer, buf, count)) {
 150                 mutex_unlock(&proxy_dev->buf_lock);
 151                 return -EFAULT;
 152         }
 153
 154         proxy_dev->resp_len = count;
 155
 156         mutex_unlock(&proxy_dev->buf_lock);
 157
 158         wake_up_interruptible(&proxy_dev->wq);
 159
 160         return count;
 161 }
 162
 163 /*
 164  * vtpm_proxy_fops_poll - Poll status on 'server side'
 165  *
 166  * @filp: file pointer
 167  * @wait: poll table
 168  *
 169  * Return: Poll flags
 170  */
 171 static __poll_t vtpm_proxy_fops_poll(struct file *filp, poll_table *wait)
 172 {
 173         struct proxy_dev *proxy_dev = filp->private_data;
 174         __poll_t ret;
 175
 176         poll_wait(filp, &proxy_dev->wq, wait);
 177
 178         ret = EPOLLOUT;
 179
 180         mutex_lock(&proxy_dev->buf_lock);
 181
 182         if (proxy_dev->req_len)
 183                 ret |= EPOLLIN | EPOLLRDNORM;
 184
 185         if (!(proxy_dev->state & STATE_OPENED_FLAG))
 186                 ret |= EPOLLHUP;
 187
 188         mutex_unlock(&proxy_dev->buf_lock);
 189
 190         return ret;
 191 }
 192
 193 /*
 194  * vtpm_proxy_fops_open - Open vTPM device on 'server side'
 195  *
 196  * @filp: file pointer
 197  *
 198  * Called when setting up the anonymous file descriptor
 199  */
 200 static void vtpm_proxy_fops_open(struct file *filp)
 201 {
 202         struct proxy_dev *proxy_dev = filp->private_data;
 203
 204         proxy_dev->state |= STATE_OPENED_FLAG;
 205 }
 206
 207 /**
 208  * vtpm_proxy_fops_undo_open - counter-part to vtpm_fops_open
 209  *       Call to undo vtpm_proxy_fops_open
 210  *
 211  *@proxy_dev: tpm proxy device
 212  */
 213 static void vtpm_proxy_fops_undo_open(struct proxy_dev *proxy_dev)
 214 {
 215         mutex_lock(&proxy_dev->buf_lock);
 216
 217         proxy_dev->state &= ~STATE_OPENED_FLAG;
 218
 219         mutex_unlock(&proxy_dev->buf_lock);
 220
 221         /* no more TPM responses -- wake up anyone waiting for them */
 222         wake_up_interruptible(&proxy_dev->wq);
 223 }
 224
 225 /*
 226  * vtpm_proxy_fops_release - Close 'server side'
 227  *
 228  * @inode: inode
 229  * @filp: file pointer
 230  * Return:
 231  *      Always returns 0.
 232  */
 233 static int vtpm_proxy_fops_release(struct inode *inode, struct file *filp)
 234 {
 235         struct proxy_dev *proxy_dev = filp->private_data;
 236
 237         filp->private_data = NULL;
 238
 239         vtpm_proxy_delete_device(proxy_dev);
 240
 241         return 0;
 242 }
 243
 244 static const struct file_operations vtpm_proxy_fops = {
 245         .owner = THIS_MODULE,
 246         .read = vtpm_proxy_fops_read,
 247         .write = vtpm_proxy_fops_write,
 248         .poll = vtpm_proxy_fops_poll,
 249         .release = vtpm_proxy_fops_release,
 250 };
 251
 252 /*
 253  * Functions invoked by the core TPM driver to send TPM commands to
 254  * 'server side' and receive responses from there.
 255  */
 256
 257 /*
 258  * Called when core TPM driver reads TPM responses from 'server side'
 259  *
 260  * @chip: tpm chip to use
 261  * @buf: receive buffer
 262  * @count: bytes to read
 263  * Return:
 264  *      Number of TPM response bytes read, negative error value otherwise
 265  */
 266 static int vtpm_proxy_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 267 {
 268         struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
 269         size_t len;
 270
 271         /* process gone ? */
 272         mutex_lock(&proxy_dev->buf_lock);
 273
 274         if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
 275                 mutex_unlock(&proxy_dev->buf_lock);
 276                 return -EPIPE;
 277         }
 278
 279         len = proxy_dev->resp_len;
 280         if (count < len) {
 281                 dev_err(&chip->dev,
 282                         "Invalid size in recv: count=%zd, resp_len=%zd\n",
 283                         count, len);
 284                 len = -EIO;
 285                 goto out;
 286         }
 287
 288         memcpy(buf, proxy_dev->buffer, len);
 289         proxy_dev->resp_len = 0;
 290
 291 out:
 292         mutex_unlock(&proxy_dev->buf_lock);
 293
 294         return len;
 295 }
 296
 297 static int vtpm_proxy_is_driver_command(struct tpm_chip *chip,
 298                                         u8 *buf, size_t count)
 299 {
 300         struct tpm_header *hdr = (struct tpm_header *)buf;
 301
 302         if (count < sizeof(struct tpm_header))
 303                 return 0;
 304
 305         if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 306                 switch (be32_to_cpu(hdr->ordinal)) {
 307                 case TPM2_CC_SET_LOCALITY:
 308                         return 1;
 309                 }
 310         } else {
 311                 switch (be32_to_cpu(hdr->ordinal)) {
 312                 case TPM_ORD_SET_LOCALITY:
 313                         return 1;
 314                 }
 315         }
 316         return 0;
 317 }
 318
 319 /*
 320  * Called when core TPM driver forwards TPM requests to 'server side'.
 321  *
 322  * @chip: tpm chip to use
 323  * @buf: send buffer
 324  * @count: bytes to send
 325  *
 326  * Return:
 327  *      0 in case of success, negative error value otherwise.
 328  */
 329 static int vtpm_proxy_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t count)
 330 {
 331         struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
 332
 333         if (count > sizeof(proxy_dev->buffer)) {
 334                 dev_err(&chip->dev,
 335                         "Invalid size in send: count=%zd, buffer size=%zd\n",
 336                         count, sizeof(proxy_dev->buffer));
 337                 return -EIO;
 338         }
 339
 340         if (!(proxy_dev->state & STATE_DRIVER_COMMAND) &&
 341             vtpm_proxy_is_driver_command(chip, buf, count))
 342                 return -EFAULT;
 343
 344         mutex_lock(&proxy_dev->buf_lock);
 345
 346         if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
 347                 mutex_unlock(&proxy_dev->buf_lock);
 348                 return -EPIPE;
 349         }
 350
 351         proxy_dev->resp_len = 0;
 352
 353         proxy_dev->req_len = count;
 354         memcpy(proxy_dev->buffer, buf, count);
 355
 356         proxy_dev->state &= ~STATE_WAIT_RESPONSE_FLAG;
 357
 358         mutex_unlock(&proxy_dev->buf_lock);
 359
 360         wake_up_interruptible(&proxy_dev->wq);
 361
 362         return 0;
 363 }
 364
 365 static void vtpm_proxy_tpm_op_cancel(struct tpm_chip *chip)
 366 {
 367         /* not supported */
 368 }
 369
 370 static u8 vtpm_proxy_tpm_op_status(struct tpm_chip *chip)
 371 {
 372         struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
 373
 374         if (proxy_dev->resp_len)
 375                 return VTPM_PROXY_REQ_COMPLETE_FLAG;
 376
 377         return 0;
 378 }
 379
 380 static bool vtpm_proxy_tpm_req_canceled(struct tpm_chip  *chip, u8 status)
 381 {
 382         struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
 383         bool ret;
 384
 385         mutex_lock(&proxy_dev->buf_lock);
 386
 387         ret = !(proxy_dev->state & STATE_OPENED_FLAG);
 388
 389         mutex_unlock(&proxy_dev->buf_lock);
 390
 391         return ret;
 392 }
 393
 394 static int vtpm_proxy_request_locality(struct tpm_chip *chip, int locality)
 395 {
 396         struct tpm_buf buf;
 397         int rc;
 398         const struct tpm_header *header;
 399         struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
 400
 401         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 402                 rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS,
 403                                   TPM2_CC_SET_LOCALITY);
 404         else
 405                 rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND,
 406                                   TPM_ORD_SET_LOCALITY);
 407         if (rc)
 408                 return rc;
 409         tpm_buf_append_u8(&buf, locality);
 410
 411         proxy_dev->state |= STATE_DRIVER_COMMAND;
 412
 413         rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to set locality");
 414
 415         proxy_dev->state &= ~STATE_DRIVER_COMMAND;
 416
 417         if (rc < 0) {
 418                 locality = rc;
 419                 goto out;
 420         }
 421
 422         header = (const struct tpm_header *)buf.data;
 423         rc = be32_to_cpu(header->return_code);
 424         if (rc)
 425                 locality = -1;
 426
 427 out:
 428         tpm_buf_destroy(&buf);
 429
 430         return locality;
 431 }
 432
 433 static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
 434         .flags = TPM_OPS_AUTO_STARTUP,
 435         .recv = vtpm_proxy_tpm_op_recv,
 436         .send = vtpm_proxy_tpm_op_send,
 437         .cancel = vtpm_proxy_tpm_op_cancel,
 438         .status = vtpm_proxy_tpm_op_status,
 439         .req_complete_mask = VTPM_PROXY_REQ_COMPLETE_FLAG,
 440         .req_complete_val = VTPM_PROXY_REQ_COMPLETE_FLAG,
 441         .req_canceled = vtpm_proxy_tpm_req_canceled,
 442         .request_locality = vtpm_proxy_request_locality,
 443 };
 444
 445 /*
 446  * Code related to the startup of the TPM 2 and startup of TPM 1.2 +
 447  * retrieval of timeouts and durations.
 448  */
 449
 450 static void vtpm_proxy_work(struct work_struct *work)
 451 {
 452         struct proxy_dev *proxy_dev = container_of(work, struct proxy_dev,
 453                                                    work);
 454         int rc;
 455
 456         rc = tpm_chip_register(proxy_dev->chip);
 457         if (rc)
 458                 vtpm_proxy_fops_undo_open(proxy_dev);
 459         else
 460                 proxy_dev->state |= STATE_REGISTERED_FLAG;
 461 }
 462
 463 /*
 464  * vtpm_proxy_work_stop: make sure the work has finished
 465  *
 466  * This function is useful when user space closed the fd
 467  * while the driver still determines timeouts.
 468  */
 469 static void vtpm_proxy_work_stop(struct proxy_dev *proxy_dev)
 470 {
 471         vtpm_proxy_fops_undo_open(proxy_dev);
 472         flush_work(&proxy_dev->work);
 473 }
 474
 475 /*
 476  * vtpm_proxy_work_start: Schedule the work for TPM 1.2 & 2 initialization
 477  */
 478 static inline void vtpm_proxy_work_start(struct proxy_dev *proxy_dev)
 479 {
 480         queue_work(workqueue, &proxy_dev->work);
 481 }
 482
 483 /*
 484  * Code related to creation and deletion of device pairs
 485  */
 486 static struct proxy_dev *vtpm_proxy_create_proxy_dev(void)
 487 {
 488         struct proxy_dev *proxy_dev;
 489         struct tpm_chip *chip;
 490         int err;
 491
 492         proxy_dev = kzalloc(sizeof(*proxy_dev), GFP_KERNEL);
 493         if (proxy_dev == NULL)
 494                 return ERR_PTR(-ENOMEM);
 495
 496         init_waitqueue_head(&proxy_dev->wq);
 497         mutex_init(&proxy_dev->buf_lock);
 498         INIT_WORK(&proxy_dev->work, vtpm_proxy_work);
 499
 500         chip = tpm_chip_alloc(NULL, &vtpm_proxy_tpm_ops);
 501         if (IS_ERR(chip)) {
 502                 err = PTR_ERR(chip);
 503                 goto err_proxy_dev_free;
 504         }
 505         dev_set_drvdata(&chip->dev, proxy_dev);
 506
 507         proxy_dev->chip = chip;
 508
 509         return proxy_dev;
 510
 511 err_proxy_dev_free:
 512         kfree(proxy_dev);
 513
 514         return ERR_PTR(err);
 515 }
 516
 517 /*
 518  * Undo what has been done in vtpm_create_proxy_dev
 519  */
 520 static inline void vtpm_proxy_delete_proxy_dev(struct proxy_dev *proxy_dev)
 521 {
 522         put_device(&proxy_dev->chip->dev); /* frees chip */
 523         kfree(proxy_dev);
 524 }
 525
 526 /*
 527  * Create a /dev/tpm%d and 'server side' file descriptor pair
 528  *
 529  * Return:
 530  *      Returns file pointer on success, an error value otherwise
 531  */
 532 static struct file *vtpm_proxy_create_device(
 533                                  struct vtpm_proxy_new_dev *vtpm_new_dev)
 534 {
 535         struct proxy_dev *proxy_dev;
 536         int rc, fd;
 537         struct file *file;
 538
 539         if (vtpm_new_dev->flags & ~VTPM_PROXY_FLAGS_ALL)
 540                 return ERR_PTR(-EOPNOTSUPP);
 541
 542         proxy_dev = vtpm_proxy_create_proxy_dev();
 543         if (IS_ERR(proxy_dev))
 544                 return ERR_CAST(proxy_dev);
 545
 546         proxy_dev->flags = vtpm_new_dev->flags;
 547
 548         /* setup an anonymous file for the server-side */
 549         fd = get_unused_fd_flags(O_RDWR);
 550         if (fd < 0) {
 551                 rc = fd;
 552                 goto err_delete_proxy_dev;
 553         }
 554
 555         file = anon_inode_getfile("[vtpms]", &vtpm_proxy_fops, proxy_dev,
 556                                   O_RDWR);
 557         if (IS_ERR(file)) {
 558                 rc = PTR_ERR(file);
 559                 goto err_put_unused_fd;
 560         }
 561
 562         /* from now on we can unwind with put_unused_fd() + fput() */
 563         /* simulate an open() on the server side */
 564         vtpm_proxy_fops_open(file);
 565
 566         if (proxy_dev->flags & VTPM_PROXY_FLAG_TPM2)
 567                 proxy_dev->chip->flags |= TPM_CHIP_FLAG_TPM2;
 568
 569         vtpm_proxy_work_start(proxy_dev);
 570
 571         vtpm_new_dev->fd = fd;
 572         vtpm_new_dev->major = MAJOR(proxy_dev->chip->dev.devt);
 573         vtpm_new_dev->minor = MINOR(proxy_dev->chip->dev.devt);
 574         vtpm_new_dev->tpm_num = proxy_dev->chip->dev_num;
 575
 576         return file;
 577
 578 err_put_unused_fd:
 579         put_unused_fd(fd);
 580
 581 err_delete_proxy_dev:
 582         vtpm_proxy_delete_proxy_dev(proxy_dev);
 583
 584         return ERR_PTR(rc);
 585 }
 586
 587 /*
 588  * Counter part to vtpm_create_device.
 589  */
 590 static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev)
 591 {
 592         vtpm_proxy_work_stop(proxy_dev);
 593
 594         /*
 595          * A client may hold the 'ops' lock, so let it know that the server
 596          * side shuts down before we try to grab the 'ops' lock when
 597          * unregistering the chip.
 598          */
 599         vtpm_proxy_fops_undo_open(proxy_dev);
 600
 601         if (proxy_dev->state & STATE_REGISTERED_FLAG)
 602                 tpm_chip_unregister(proxy_dev->chip);
 603
 604         vtpm_proxy_delete_proxy_dev(proxy_dev);
 605 }
 606
 607 /*
 608  * Code related to the control device /dev/vtpmx
 609  */
 610
 611 /**
 612  * vtpmx_ioc_new_dev - handler for the %VTPM_PROXY_IOC_NEW_DEV ioctl
 613  * @file:       /dev/vtpmx
 614  * @ioctl:      the ioctl number
 615  * @arg:        pointer to the struct vtpmx_proxy_new_dev
 616  *
 617  * Creates an anonymous file that is used by the process acting as a TPM to
 618  * communicate with the client processes. The function will also add a new TPM
 619  * device through which data is proxied to this TPM acting process. The caller
 620  * will be provided with a file descriptor to communicate with the clients and
 621  * major and minor numbers for the TPM device.
 622  */
 623 static long vtpmx_ioc_new_dev(struct file *file, unsigned int ioctl,
 624                               unsigned long arg)
 625 {
 626         void __user *argp = (void __user *)arg;
 627         struct vtpm_proxy_new_dev __user *vtpm_new_dev_p;
 628         struct vtpm_proxy_new_dev vtpm_new_dev;
 629         struct file *vtpm_file;
 630
 631         if (!capable(CAP_SYS_ADMIN))
 632                 return -EPERM;
 633
 634         vtpm_new_dev_p = argp;
 635
 636         if (copy_from_user(&vtpm_new_dev, vtpm_new_dev_p,
 637                            sizeof(vtpm_new_dev)))
 638                 return -EFAULT;
 639
 640         vtpm_file = vtpm_proxy_create_device(&vtpm_new_dev);
 641         if (IS_ERR(vtpm_file))
 642                 return PTR_ERR(vtpm_file);
 643
 644         if (copy_to_user(vtpm_new_dev_p, &vtpm_new_dev,
 645                          sizeof(vtpm_new_dev))) {
 646                 put_unused_fd(vtpm_new_dev.fd);
 647                 fput(vtpm_file);
 648                 return -EFAULT;
 649         }
 650
 651         fd_install(vtpm_new_dev.fd, vtpm_file);
 652         return 0;
 653 }
 654
 655 /*
 656  * vtpmx_fops_ioctl: ioctl on /dev/vtpmx
 657  *
 658  * Return:
 659  *      Returns 0 on success, a negative error code otherwise.
 660  */
 661 static long vtpmx_fops_ioctl(struct file *f, unsigned int ioctl,
 662                              unsigned long arg)
 663 {
 664         switch (ioctl) {
 665         case VTPM_PROXY_IOC_NEW_DEV:
 666                 return vtpmx_ioc_new_dev(f, ioctl, arg);
 667         default:
 668                 return -ENOIOCTLCMD;
 669         }
 670 }
 671
 672 static const struct file_operations vtpmx_fops = {
 673         .owner = THIS_MODULE,
 674         .unlocked_ioctl = vtpmx_fops_ioctl,
 675         .compat_ioctl = compat_ptr_ioctl,
 676         .llseek = noop_llseek,
 677 };
 678
 679 static struct miscdevice vtpmx_miscdev = {
 680         .minor = MISC_DYNAMIC_MINOR,
 681         .name = "vtpmx",
 682         .fops = &vtpmx_fops,
 683 };
 684
 685 static int __init vtpm_module_init(void)
 686 {
 687         int rc;
 688
 689         workqueue = create_workqueue("tpm-vtpm");
 690         if (!workqueue) {
 691                 pr_err("couldn't create workqueue\n");
 692                 return -ENOMEM;
 693         }
 694
 695         rc = misc_register(&vtpmx_miscdev);
 696         if (rc) {
 697                 pr_err("couldn't create vtpmx device\n");
 698                 destroy_workqueue(workqueue);
 699         }
 700
 701         return rc;
 702 }
 703
 704 static void __exit vtpm_module_exit(void)
 705 {
 706         destroy_workqueue(workqueue);
 707         misc_deregister(&vtpmx_miscdev);
 708 }
 709
 710 module_init(vtpm_module_init);
 711 module_exit(vtpm_module_exit);
 712
 713 MODULE_AUTHOR("Stefan Berger <stefanb@us.ibm.com>");
 714 MODULE_DESCRIPTION("vTPM Driver");
 715 MODULE_VERSION("0.1");
 716 MODULE_LICENSE("GPL");