drivers/firmware/efi/test/efi_test.c

   1 /*
   2  * EFI Test Driver for Runtime Services
   3  *
   4  * Copyright(C) 2012-2016 Canonical Ltd.
   5  *
   6  * This driver exports EFI runtime services interfaces into userspace, which
   7  * allow to use and test UEFI runtime services provided by firmware.
   8  *
   9  */
  10
  11 #include <linux/miscdevice.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/efi.h>
  16 #include <linux/slab.h>
  17 #include <linux/uaccess.h>
  18
  19 #include "efi_test.h"
  20
  21 MODULE_AUTHOR("Ivan Hu <[email protected]>");
  22 MODULE_DESCRIPTION("EFI Test Driver");
  23 MODULE_LICENSE("GPL");
  24
  25 /*
  26  * Count the bytes in 'str', including the terminating NULL.
  27  *
  28  * Note this function returns the number of *bytes*, not the number of
  29  * ucs2 characters.
  30  */
  31 static inline size_t user_ucs2_strsize(efi_char16_t  __user *str)
  32 {
  33         efi_char16_t *s = str, c;
  34         size_t len;
  35
  36         if (!str)
  37                 return 0;
  38
  39         /* Include terminating NULL */
  40         len = sizeof(efi_char16_t);
  41
  42         if (get_user(c, s++)) {
  43                 /* Can't read userspace memory for size */
  44                 return 0;
  45         }
  46
  47         while (c != 0) {
  48                 if (get_user(c, s++)) {
  49                         /* Can't read userspace memory for size */
  50                         return 0;
  51                 }
  52                 len += sizeof(efi_char16_t);
  53         }
  54         return len;
  55 }
  56
  57 /*
  58  * Allocate a buffer and copy a ucs2 string from user space into it.
  59  */
  60 static inline int
  61 copy_ucs2_from_user_len(efi_char16_t **dst, efi_char16_t __user *src,
  62                         size_t len)
  63 {
  64         efi_char16_t *buf;
  65
  66         if (!src) {
  67                 *dst = NULL;
  68                 return 0;
  69         }
  70
  71         if (!access_ok(VERIFY_READ, src, 1))
  72                 return -EFAULT;
  73
  74         buf = memdup_user(src, len);
  75         if (IS_ERR(buf)) {
  76                 *dst = NULL;
  77                 return PTR_ERR(buf);
  78         }
  79         *dst = buf;
  80
  81         return 0;
  82 }
  83
  84 /*
  85  * Count the bytes in 'str', including the terminating NULL.
  86  *
  87  * Just a wrap for user_ucs2_strsize
  88  */
  89 static inline int
  90 get_ucs2_strsize_from_user(efi_char16_t __user *src, size_t *len)
  91 {
  92         if (!access_ok(VERIFY_READ, src, 1))
  93                 return -EFAULT;
  94
  95         *len = user_ucs2_strsize(src);
  96         if (*len == 0)
  97                 return -EFAULT;
  98
  99         return 0;
 100 }
 101
 102 /*
 103  * Calculate the required buffer allocation size and copy a ucs2 string
 104  * from user space into it.
 105  *
 106  * This function differs from copy_ucs2_from_user_len() because it
 107  * calculates the size of the buffer to allocate by taking the length of
 108  * the string 'src'.
 109  *
 110  * If a non-zero value is returned, the caller MUST NOT access 'dst'.
 111  *
 112  * It is the caller's responsibility to free 'dst'.
 113  */
 114 static inline int
 115 copy_ucs2_from_user(efi_char16_t **dst, efi_char16_t __user *src)
 116 {
 117         size_t len;
 118
 119         if (!access_ok(VERIFY_READ, src, 1))
 120                 return -EFAULT;
 121
 122         len = user_ucs2_strsize(src);
 123         if (len == 0)
 124                 return -EFAULT;
 125         return copy_ucs2_from_user_len(dst, src, len);
 126 }
 127
 128 /*
 129  * Copy a ucs2 string to a user buffer.
 130  *
 131  * This function is a simple wrapper around copy_to_user() that does
 132  * nothing if 'src' is NULL, which is useful for reducing the amount of
 133  * NULL checking the caller has to do.
 134  *
 135  * 'len' specifies the number of bytes to copy.
 136  */
 137 static inline int
 138 copy_ucs2_to_user_len(efi_char16_t __user *dst, efi_char16_t *src, size_t len)
 139 {
 140         if (!src)
 141                 return 0;
 142
 143         if (!access_ok(VERIFY_WRITE, dst, 1))
 144                 return -EFAULT;
 145
 146         return copy_to_user(dst, src, len);
 147 }
 148
 149 static long efi_runtime_get_variable(unsigned long arg)
 150 {
 151         struct efi_getvariable __user *getvariable_user;
 152         struct efi_getvariable getvariable;
 153         unsigned long datasize = 0, prev_datasize, *dz;
 154         efi_guid_t vendor_guid, *vd = NULL;
 155         efi_status_t status;
 156         efi_char16_t *name = NULL;
 157         u32 attr, *at;
 158         void *data = NULL;
 159         int rv = 0;
 160
 161         getvariable_user = (struct efi_getvariable __user *)arg;
 162
 163         if (copy_from_user(&getvariable, getvariable_user,
 164                            sizeof(getvariable)))
 165                 return -EFAULT;
 166         if (getvariable.data_size &&
 167             get_user(datasize, getvariable.data_size))
 168                 return -EFAULT;
 169         if (getvariable.vendor_guid) {
 170                 if (copy_from_user(&vendor_guid, getvariable.vendor_guid,
 171                                         sizeof(vendor_guid)))
 172                         return -EFAULT;
 173                 vd = &vendor_guid;
 174         }
 175
 176         if (getvariable.variable_name) {
 177                 rv = copy_ucs2_from_user(&name, getvariable.variable_name);
 178                 if (rv)
 179                         return rv;
 180         }
 181
 182         at = getvariable.attributes ? &attr : NULL;
 183         dz = getvariable.data_size ? &datasize : NULL;
 184
 185         if (getvariable.data_size && getvariable.data) {
 186                 data = kmalloc(datasize, GFP_KERNEL);
 187                 if (!data) {
 188                         kfree(name);
 189                         return -ENOMEM;
 190                 }
 191         }
 192
 193         prev_datasize = datasize;
 194         status = efi.get_variable(name, vd, at, dz, data);
 195         kfree(name);
 196
 197         if (put_user(status, getvariable.status)) {
 198                 rv = -EFAULT;
 199                 goto out;
 200         }
 201
 202         if (status != EFI_SUCCESS) {
 203                 if (status == EFI_BUFFER_TOO_SMALL) {
 204                         if (dz && put_user(datasize, getvariable.data_size)) {
 205                                 rv = -EFAULT;
 206                                 goto out;
 207                         }
 208                 }
 209                 rv = -EINVAL;
 210                 goto out;
 211         }
 212
 213         if (prev_datasize < datasize) {
 214                 rv = -EINVAL;
 215                 goto out;
 216         }
 217
 218         if (data) {
 219                 if (copy_to_user(getvariable.data, data, datasize)) {
 220                         rv = -EFAULT;
 221                         goto out;
 222                 }
 223         }
 224
 225         if (at && put_user(attr, getvariable.attributes)) {
 226                 rv = -EFAULT;
 227                 goto out;
 228         }
 229
 230         if (dz && put_user(datasize, getvariable.data_size))
 231                 rv = -EFAULT;
 232
 233 out:
 234         kfree(data);
 235         return rv;
 236
 237 }
 238
 239 static long efi_runtime_set_variable(unsigned long arg)
 240 {
 241         struct efi_setvariable __user *setvariable_user;
 242         struct efi_setvariable setvariable;
 243         efi_guid_t vendor_guid;
 244         efi_status_t status;
 245         efi_char16_t *name = NULL;
 246         void *data;
 247         int rv = 0;
 248
 249         setvariable_user = (struct efi_setvariable __user *)arg;
 250
 251         if (copy_from_user(&setvariable, setvariable_user, sizeof(setvariable)))
 252                 return -EFAULT;
 253         if (copy_from_user(&vendor_guid, setvariable.vendor_guid,
 254                                 sizeof(vendor_guid)))
 255                 return -EFAULT;
 256
 257         if (setvariable.variable_name) {
 258                 rv = copy_ucs2_from_user(&name, setvariable.variable_name);
 259                 if (rv)
 260                         return rv;
 261         }
 262
 263         data = memdup_user(setvariable.data, setvariable.data_size);
 264         if (IS_ERR(data)) {
 265                 kfree(name);
 266                 return PTR_ERR(data);
 267         }
 268
 269         status = efi.set_variable(name, &vendor_guid,
 270                                 setvariable.attributes,
 271                                 setvariable.data_size, data);
 272
 273         if (put_user(status, setvariable.status)) {
 274                 rv = -EFAULT;
 275                 goto out;
 276         }
 277
 278         rv = status == EFI_SUCCESS ? 0 : -EINVAL;
 279
 280 out:
 281         kfree(data);
 282         kfree(name);
 283
 284         return rv;
 285 }
 286
 287 static long efi_runtime_get_time(unsigned long arg)
 288 {
 289         struct efi_gettime __user *gettime_user;
 290         struct efi_gettime  gettime;
 291         efi_status_t status;
 292         efi_time_cap_t cap;
 293         efi_time_t efi_time;
 294
 295         gettime_user = (struct efi_gettime __user *)arg;
 296         if (copy_from_user(&gettime, gettime_user, sizeof(gettime)))
 297                 return -EFAULT;
 298
 299         status = efi.get_time(gettime.time ? &efi_time : NULL,
 300                               gettime.capabilities ? &cap : NULL);
 301
 302         if (put_user(status, gettime.status))
 303                 return -EFAULT;
 304
 305         if (status != EFI_SUCCESS)
 306                 return -EINVAL;
 307
 308         if (gettime.capabilities) {
 309                 efi_time_cap_t __user *cap_local;
 310
 311                 cap_local = (efi_time_cap_t *)gettime.capabilities;
 312                 if (put_user(cap.resolution, &(cap_local->resolution)) ||
 313                         put_user(cap.accuracy, &(cap_local->accuracy)) ||
 314                         put_user(cap.sets_to_zero, &(cap_local->sets_to_zero)))
 315                         return -EFAULT;
 316         }
 317         if (gettime.time) {
 318                 if (copy_to_user(gettime.time, &efi_time, sizeof(efi_time_t)))
 319                         return -EFAULT;
 320         }
 321
 322         return 0;
 323 }
 324
 325 static long efi_runtime_set_time(unsigned long arg)
 326 {
 327         struct efi_settime __user *settime_user;
 328         struct efi_settime settime;
 329         efi_status_t status;
 330         efi_time_t efi_time;
 331
 332         settime_user = (struct efi_settime __user *)arg;
 333         if (copy_from_user(&settime, settime_user, sizeof(settime)))
 334                 return -EFAULT;
 335         if (copy_from_user(&efi_time, settime.time,
 336                                         sizeof(efi_time_t)))
 337                 return -EFAULT;
 338         status = efi.set_time(&efi_time);
 339
 340         if (put_user(status, settime.status))
 341                 return -EFAULT;
 342
 343         return status == EFI_SUCCESS ? 0 : -EINVAL;
 344 }
 345
 346 static long efi_runtime_get_waketime(unsigned long arg)
 347 {
 348         struct efi_getwakeuptime __user *getwakeuptime_user;
 349         struct efi_getwakeuptime getwakeuptime;
 350         efi_bool_t enabled, pending;
 351         efi_status_t status;
 352         efi_time_t efi_time;
 353
 354         getwakeuptime_user = (struct efi_getwakeuptime __user *)arg;
 355         if (copy_from_user(&getwakeuptime, getwakeuptime_user,
 356                                 sizeof(getwakeuptime)))
 357                 return -EFAULT;
 358
 359         status = efi.get_wakeup_time(
 360                 getwakeuptime.enabled ? (efi_bool_t *)&enabled : NULL,
 361                 getwakeuptime.pending ? (efi_bool_t *)&pending : NULL,
 362                 getwakeuptime.time ? &efi_time : NULL);
 363
 364         if (put_user(status, getwakeuptime.status))
 365                 return -EFAULT;
 366
 367         if (status != EFI_SUCCESS)
 368                 return -EINVAL;
 369
 370         if (getwakeuptime.enabled && put_user(enabled,
 371                                                 getwakeuptime.enabled))
 372                 return -EFAULT;
 373
 374         if (getwakeuptime.time) {
 375                 if (copy_to_user(getwakeuptime.time, &efi_time,
 376                                 sizeof(efi_time_t)))
 377                         return -EFAULT;
 378         }
 379
 380         return 0;
 381 }
 382
 383 static long efi_runtime_set_waketime(unsigned long arg)
 384 {
 385         struct efi_setwakeuptime __user *setwakeuptime_user;
 386         struct efi_setwakeuptime setwakeuptime;
 387         efi_bool_t enabled;
 388         efi_status_t status;
 389         efi_time_t efi_time;
 390
 391         setwakeuptime_user = (struct efi_setwakeuptime __user *)arg;
 392
 393         if (copy_from_user(&setwakeuptime, setwakeuptime_user,
 394                                 sizeof(setwakeuptime)))
 395                 return -EFAULT;
 396
 397         enabled = setwakeuptime.enabled;
 398         if (setwakeuptime.time) {
 399                 if (copy_from_user(&efi_time, setwakeuptime.time,
 400                                         sizeof(efi_time_t)))
 401                         return -EFAULT;
 402
 403                 status = efi.set_wakeup_time(enabled, &efi_time);
 404         } else
 405                 status = efi.set_wakeup_time(enabled, NULL);
 406
 407         if (put_user(status, setwakeuptime.status))
 408                 return -EFAULT;
 409
 410         return status == EFI_SUCCESS ? 0 : -EINVAL;
 411 }
 412
 413 static long efi_runtime_get_nextvariablename(unsigned long arg)
 414 {
 415         struct efi_getnextvariablename __user *getnextvariablename_user;
 416         struct efi_getnextvariablename getnextvariablename;
 417         unsigned long name_size, prev_name_size = 0, *ns = NULL;
 418         efi_status_t status;
 419         efi_guid_t *vd = NULL;
 420         efi_guid_t vendor_guid;
 421         efi_char16_t *name = NULL;
 422         int rv = 0;
 423
 424         getnextvariablename_user = (struct efi_getnextvariablename __user *)arg;
 425
 426         if (copy_from_user(&getnextvariablename, getnextvariablename_user,
 427                            sizeof(getnextvariablename)))
 428                 return -EFAULT;
 429
 430         if (getnextvariablename.variable_name_size) {
 431                 if (get_user(name_size, getnextvariablename.variable_name_size))
 432                         return -EFAULT;
 433                 ns = &name_size;
 434                 prev_name_size = name_size;
 435         }
 436
 437         if (getnextvariablename.vendor_guid) {
 438                 if (copy_from_user(&vendor_guid,
 439                                 getnextvariablename.vendor_guid,
 440                                 sizeof(vendor_guid)))
 441                         return -EFAULT;
 442                 vd = &vendor_guid;
 443         }
 444
 445         if (getnextvariablename.variable_name) {
 446                 size_t name_string_size = 0;
 447
 448                 rv = get_ucs2_strsize_from_user(
 449                                 getnextvariablename.variable_name,
 450                                 &name_string_size);
 451                 if (rv)
 452                         return rv;
 453                 /*
 454                  * The name_size may be smaller than the real buffer size where
 455                  * variable name located in some use cases. The most typical
 456                  * case is passing a 0 to get the required buffer size for the
 457                  * 1st time call. So we need to copy the content from user
 458                  * space for at least the string size of variable name, or else
 459                  * the name passed to UEFI may not be terminated as we expected.
 460                  */
 461                 rv = copy_ucs2_from_user_len(&name,
 462                                 getnextvariablename.variable_name,
 463                                 prev_name_size > name_string_size ?
 464                                 prev_name_size : name_string_size);
 465                 if (rv)
 466                         return rv;
 467         }
 468
 469         status = efi.get_next_variable(ns, name, vd);
 470
 471         if (put_user(status, getnextvariablename.status)) {
 472                 rv = -EFAULT;
 473                 goto out;
 474         }
 475
 476         if (status != EFI_SUCCESS) {
 477                 if (status == EFI_BUFFER_TOO_SMALL) {
 478                         if (ns && put_user(*ns,
 479                                 getnextvariablename.variable_name_size)) {
 480                                 rv = -EFAULT;
 481                                 goto out;
 482                         }
 483                 }
 484                 rv = -EINVAL;
 485                 goto out;
 486         }
 487
 488         if (name) {
 489                 if (copy_ucs2_to_user_len(getnextvariablename.variable_name,
 490                                                 name, prev_name_size)) {
 491                         rv = -EFAULT;
 492                         goto out;
 493                 }
 494         }
 495
 496         if (ns) {
 497                 if (put_user(*ns, getnextvariablename.variable_name_size)) {
 498                         rv = -EFAULT;
 499                         goto out;
 500                 }
 501         }
 502
 503         if (vd) {
 504                 if (copy_to_user(getnextvariablename.vendor_guid, vd,
 505                                                         sizeof(efi_guid_t)))
 506                         rv = -EFAULT;
 507         }
 508
 509 out:
 510         kfree(name);
 511         return rv;
 512 }
 513
 514 static long efi_runtime_get_nexthighmonocount(unsigned long arg)
 515 {
 516         struct efi_getnexthighmonotoniccount __user *getnexthighmonocount_user;
 517         struct efi_getnexthighmonotoniccount getnexthighmonocount;
 518         efi_status_t status;
 519         u32 count;
 520
 521         getnexthighmonocount_user = (struct
 522                         efi_getnexthighmonotoniccount __user *)arg;
 523
 524         if (copy_from_user(&getnexthighmonocount,
 525                            getnexthighmonocount_user,
 526                            sizeof(getnexthighmonocount)))
 527                 return -EFAULT;
 528
 529         status = efi.get_next_high_mono_count(
 530                 getnexthighmonocount.high_count ? &count : NULL);
 531
 532         if (put_user(status, getnexthighmonocount.status))
 533                 return -EFAULT;
 534
 535         if (status != EFI_SUCCESS)
 536                 return -EINVAL;
 537
 538         if (getnexthighmonocount.high_count &&
 539             put_user(count, getnexthighmonocount.high_count))
 540                 return -EFAULT;
 541
 542         return 0;
 543 }
 544
 545 static long efi_runtime_reset_system(unsigned long arg)
 546 {
 547         struct efi_resetsystem __user *resetsystem_user;
 548         struct efi_resetsystem resetsystem;
 549         void *data = NULL;
 550
 551         resetsystem_user = (struct efi_resetsystem __user *)arg;
 552         if (copy_from_user(&resetsystem, resetsystem_user,
 553                                                 sizeof(resetsystem)))
 554                 return -EFAULT;
 555         if (resetsystem.data_size != 0) {
 556                 data = memdup_user((void *)resetsystem.data,
 557                                                 resetsystem.data_size);
 558                 if (IS_ERR(data))
 559                         return PTR_ERR(data);
 560         }
 561
 562         efi.reset_system(resetsystem.reset_type, resetsystem.status,
 563                                 resetsystem.data_size, (efi_char16_t *)data);
 564
 565         kfree(data);
 566         return 0;
 567 }
 568
 569 static long efi_runtime_query_variableinfo(unsigned long arg)
 570 {
 571         struct efi_queryvariableinfo __user *queryvariableinfo_user;
 572         struct efi_queryvariableinfo queryvariableinfo;
 573         efi_status_t status;
 574         u64 max_storage, remaining, max_size;
 575
 576         queryvariableinfo_user = (struct efi_queryvariableinfo __user *)arg;
 577
 578         if (copy_from_user(&queryvariableinfo, queryvariableinfo_user,
 579                            sizeof(queryvariableinfo)))
 580                 return -EFAULT;
 581
 582         status = efi.query_variable_info(queryvariableinfo.attributes,
 583                                          &max_storage, &remaining, &max_size);
 584
 585         if (put_user(status, queryvariableinfo.status))
 586                 return -EFAULT;
 587
 588         if (status != EFI_SUCCESS)
 589                 return -EINVAL;
 590
 591         if (put_user(max_storage,
 592                      queryvariableinfo.maximum_variable_storage_size))
 593                 return -EFAULT;
 594
 595         if (put_user(remaining,
 596                      queryvariableinfo.remaining_variable_storage_size))
 597                 return -EFAULT;
 598
 599         if (put_user(max_size, queryvariableinfo.maximum_variable_size))
 600                 return -EFAULT;
 601
 602         return 0;
 603 }
 604
 605 static long efi_runtime_query_capsulecaps(unsigned long arg)
 606 {
 607         struct efi_querycapsulecapabilities __user *qcaps_user;
 608         struct efi_querycapsulecapabilities qcaps;
 609         efi_capsule_header_t *capsules;
 610         efi_status_t status;
 611         u64 max_size;
 612         int i, reset_type;
 613         int rv = 0;
 614
 615         qcaps_user = (struct efi_querycapsulecapabilities __user *)arg;
 616
 617         if (copy_from_user(&qcaps, qcaps_user, sizeof(qcaps)))
 618                 return -EFAULT;
 619
 620         if (qcaps.capsule_count == ULONG_MAX)
 621                 return -EINVAL;
 622
 623         capsules = kcalloc(qcaps.capsule_count + 1,
 624                            sizeof(efi_capsule_header_t), GFP_KERNEL);
 625         if (!capsules)
 626                 return -ENOMEM;
 627
 628         for (i = 0; i < qcaps.capsule_count; i++) {
 629                 efi_capsule_header_t *c;
 630                 /*
 631                  * We cannot dereference qcaps.capsule_header_array directly to
 632                  * obtain the address of the capsule as it resides in the
 633                  * user space
 634                  */
 635                 if (get_user(c, qcaps.capsule_header_array + i)) {
 636                         rv = -EFAULT;
 637                         goto out;
 638                 }
 639                 if (copy_from_user(&capsules[i], c,
 640                                 sizeof(efi_capsule_header_t))) {
 641                         rv = -EFAULT;
 642                         goto out;
 643                 }
 644         }
 645
 646         qcaps.capsule_header_array = &capsules;
 647
 648         status = efi.query_capsule_caps((efi_capsule_header_t **)
 649                                         qcaps.capsule_header_array,
 650                                         qcaps.capsule_count,
 651                                         &max_size, &reset_type);
 652
 653         if (put_user(status, qcaps.status)) {
 654                 rv = -EFAULT;
 655                 goto out;
 656         }
 657
 658         if (status != EFI_SUCCESS) {
 659                 rv = -EINVAL;
 660                 goto out;
 661         }
 662
 663         if (put_user(max_size, qcaps.maximum_capsule_size)) {
 664                 rv = -EFAULT;
 665                 goto out;
 666         }
 667
 668         if (put_user(reset_type, qcaps.reset_type))
 669                 rv = -EFAULT;
 670
 671 out:
 672         kfree(capsules);
 673         return rv;
 674 }
 675
 676 static long efi_test_ioctl(struct file *file, unsigned int cmd,
 677                                                         unsigned long arg)
 678 {
 679         switch (cmd) {
 680         case EFI_RUNTIME_GET_VARIABLE:
 681                 return efi_runtime_get_variable(arg);
 682
 683         case EFI_RUNTIME_SET_VARIABLE:
 684                 return efi_runtime_set_variable(arg);
 685
 686         case EFI_RUNTIME_GET_TIME:
 687                 return efi_runtime_get_time(arg);
 688
 689         case EFI_RUNTIME_SET_TIME:
 690                 return efi_runtime_set_time(arg);
 691
 692         case EFI_RUNTIME_GET_WAKETIME:
 693                 return efi_runtime_get_waketime(arg);
 694
 695         case EFI_RUNTIME_SET_WAKETIME:
 696                 return efi_runtime_set_waketime(arg);
 697
 698         case EFI_RUNTIME_GET_NEXTVARIABLENAME:
 699                 return efi_runtime_get_nextvariablename(arg);
 700
 701         case EFI_RUNTIME_GET_NEXTHIGHMONOTONICCOUNT:
 702                 return efi_runtime_get_nexthighmonocount(arg);
 703
 704         case EFI_RUNTIME_QUERY_VARIABLEINFO:
 705                 return efi_runtime_query_variableinfo(arg);
 706
 707         case EFI_RUNTIME_QUERY_CAPSULECAPABILITIES:
 708                 return efi_runtime_query_capsulecaps(arg);
 709
 710         case EFI_RUNTIME_RESET_SYSTEM:
 711                 return efi_runtime_reset_system(arg);
 712         }
 713
 714         return -ENOTTY;
 715 }
 716
 717 static int efi_test_open(struct inode *inode, struct file *file)
 718 {
 719         /*
 720          * nothing special to do here
 721          * We do accept multiple open files at the same time as we
 722          * synchronize on the per call operation.
 723          */
 724         return 0;
 725 }
 726
 727 static int efi_test_close(struct inode *inode, struct file *file)
 728 {
 729         return 0;
 730 }
 731
 732 /*
 733  *      The various file operations we support.
 734  */
 735 static const struct file_operations efi_test_fops = {
 736         .owner          = THIS_MODULE,
 737         .unlocked_ioctl = efi_test_ioctl,
 738         .open           = efi_test_open,
 739         .release        = efi_test_close,
 740         .llseek         = no_llseek,
 741 };
 742
 743 static struct miscdevice efi_test_dev = {
 744         MISC_DYNAMIC_MINOR,
 745         "efi_test",
 746         &efi_test_fops
 747 };
 748
 749 static int __init efi_test_init(void)
 750 {
 751         int ret;
 752
 753         ret = misc_register(&efi_test_dev);
 754         if (ret) {
 755                 pr_err("efi_test: can't misc_register on minor=%d\n",
 756                         MISC_DYNAMIC_MINOR);
 757                 return ret;
 758         }
 759
 760         return 0;
 761 }
 762
 763 static void __exit efi_test_exit(void)
 764 {
 765         misc_deregister(&efi_test_dev);
 766 }
 767
 768 module_init(efi_test_init);
 769 module_exit(efi_test_exit);