drivers/char/tpm/tpm2-cmd.c

   1 /*
   2  * Copyright (C) 2014 Intel Corporation
   3  *
   4  * Authors:
   5  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
   6  *
   7  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
   8  *
   9  * This file contains TPM2 protocol implementations of the commands
  10  * used by the kernel internally.
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; version 2
  15  * of the License.
  16  */
  17
  18 #include "tpm.h"
  19
  20 struct tpm2_startup_in {
  21         __be16  startup_type;
  22 } __packed;
  23
  24 struct tpm2_self_test_in {
  25         u8      full_test;
  26 } __packed;
  27
  28 struct tpm2_pcr_read_in {
  29         __be32  pcr_selects_cnt;
  30         __be16  hash_alg;
  31         u8      pcr_select_size;
  32         u8      pcr_select[TPM2_PCR_SELECT_MIN];
  33 } __packed;
  34
  35 struct tpm2_pcr_read_out {
  36         __be32  update_cnt;
  37         __be32  pcr_selects_cnt;
  38         __be16  hash_alg;
  39         u8      pcr_select_size;
  40         u8      pcr_select[TPM2_PCR_SELECT_MIN];
  41         __be32  digests_cnt;
  42         __be16  digest_size;
  43         u8      digest[TPM_DIGEST_SIZE];
  44 } __packed;
  45
  46 struct tpm2_null_auth_area {
  47         __be32                  handle;
  48         __be16                  nonce_size;
  49         u8                      attributes;
  50         __be16                  auth_size;
  51 } __packed;
  52
  53 struct tpm2_pcr_extend_in {
  54         __be32                          pcr_idx;
  55         __be32                          auth_area_size;
  56         struct tpm2_null_auth_area      auth_area;
  57         __be32                          digest_cnt;
  58         __be16                          hash_alg;
  59         u8                              digest[TPM_DIGEST_SIZE];
  60 } __packed;
  61
  62 struct tpm2_get_tpm_pt_in {
  63         __be32  cap_id;
  64         __be32  property_id;
  65         __be32  property_cnt;
  66 } __packed;
  67
  68 struct tpm2_get_tpm_pt_out {
  69         u8      more_data;
  70         __be32  subcap_id;
  71         __be32  property_cnt;
  72         __be32  property_id;
  73         __be32  value;
  74 } __packed;
  75
  76 struct tpm2_get_random_in {
  77         __be16  size;
  78 } __packed;
  79
  80 struct tpm2_get_random_out {
  81         __be16  size;
  82         u8      buffer[TPM_MAX_RNG_DATA];
  83 } __packed;
  84
  85 union tpm2_cmd_params {
  86         struct  tpm2_startup_in         startup_in;
  87         struct  tpm2_self_test_in       selftest_in;
  88         struct  tpm2_pcr_read_in        pcrread_in;
  89         struct  tpm2_pcr_read_out       pcrread_out;
  90         struct  tpm2_pcr_extend_in      pcrextend_in;
  91         struct  tpm2_get_tpm_pt_in      get_tpm_pt_in;
  92         struct  tpm2_get_tpm_pt_out     get_tpm_pt_out;
  93         struct  tpm2_get_random_in      getrandom_in;
  94         struct  tpm2_get_random_out     getrandom_out;
  95 };
  96
  97 struct tpm2_cmd {
  98         tpm_cmd_header          header;
  99         union tpm2_cmd_params   params;
 100 } __packed;
 101
 102 /*
 103  * Array with one entry per ordinal defining the maximum amount
 104  * of time the chip could take to return the result. The values
 105  * of the SHORT, MEDIUM, and LONG durations are taken from the
 106  * PC Client Profile (PTP) specification.
 107  */
 108 static const u8 tpm2_ordinal_duration[TPM2_CC_LAST - TPM2_CC_FIRST + 1] = {
 109         TPM_UNDEFINED,          /* 11F */
 110         TPM_UNDEFINED,          /* 120 */
 111         TPM_LONG,               /* 121 */
 112         TPM_UNDEFINED,          /* 122 */
 113         TPM_UNDEFINED,          /* 123 */
 114         TPM_UNDEFINED,          /* 124 */
 115         TPM_UNDEFINED,          /* 125 */
 116         TPM_UNDEFINED,          /* 126 */
 117         TPM_UNDEFINED,          /* 127 */
 118         TPM_UNDEFINED,          /* 128 */
 119         TPM_LONG,               /* 129 */
 120         TPM_UNDEFINED,          /* 12a */
 121         TPM_UNDEFINED,          /* 12b */
 122         TPM_UNDEFINED,          /* 12c */
 123         TPM_UNDEFINED,          /* 12d */
 124         TPM_UNDEFINED,          /* 12e */
 125         TPM_UNDEFINED,          /* 12f */
 126         TPM_UNDEFINED,          /* 130 */
 127         TPM_UNDEFINED,          /* 131 */
 128         TPM_UNDEFINED,          /* 132 */
 129         TPM_UNDEFINED,          /* 133 */
 130         TPM_UNDEFINED,          /* 134 */
 131         TPM_UNDEFINED,          /* 135 */
 132         TPM_UNDEFINED,          /* 136 */
 133         TPM_UNDEFINED,          /* 137 */
 134         TPM_UNDEFINED,          /* 138 */
 135         TPM_UNDEFINED,          /* 139 */
 136         TPM_UNDEFINED,          /* 13a */
 137         TPM_UNDEFINED,          /* 13b */
 138         TPM_UNDEFINED,          /* 13c */
 139         TPM_UNDEFINED,          /* 13d */
 140         TPM_MEDIUM,             /* 13e */
 141         TPM_UNDEFINED,          /* 13f */
 142         TPM_UNDEFINED,          /* 140 */
 143         TPM_UNDEFINED,          /* 141 */
 144         TPM_UNDEFINED,          /* 142 */
 145         TPM_LONG,               /* 143 */
 146         TPM_MEDIUM,             /* 144 */
 147         TPM_UNDEFINED,          /* 145 */
 148         TPM_UNDEFINED,          /* 146 */
 149         TPM_UNDEFINED,          /* 147 */
 150         TPM_UNDEFINED,          /* 148 */
 151         TPM_UNDEFINED,          /* 149 */
 152         TPM_UNDEFINED,          /* 14a */
 153         TPM_UNDEFINED,          /* 14b */
 154         TPM_UNDEFINED,          /* 14c */
 155         TPM_UNDEFINED,          /* 14d */
 156         TPM_LONG,               /* 14e */
 157         TPM_UNDEFINED,          /* 14f */
 158         TPM_UNDEFINED,          /* 150 */
 159         TPM_UNDEFINED,          /* 151 */
 160         TPM_UNDEFINED,          /* 152 */
 161         TPM_UNDEFINED,          /* 153 */
 162         TPM_UNDEFINED,          /* 154 */
 163         TPM_UNDEFINED,          /* 155 */
 164         TPM_UNDEFINED,          /* 156 */
 165         TPM_UNDEFINED,          /* 157 */
 166         TPM_UNDEFINED,          /* 158 */
 167         TPM_UNDEFINED,          /* 159 */
 168         TPM_UNDEFINED,          /* 15a */
 169         TPM_UNDEFINED,          /* 15b */
 170         TPM_MEDIUM,             /* 15c */
 171         TPM_UNDEFINED,          /* 15d */
 172         TPM_UNDEFINED,          /* 15e */
 173         TPM_UNDEFINED,          /* 15f */
 174         TPM_UNDEFINED,          /* 160 */
 175         TPM_UNDEFINED,          /* 161 */
 176         TPM_UNDEFINED,          /* 162 */
 177         TPM_UNDEFINED,          /* 163 */
 178         TPM_UNDEFINED,          /* 164 */
 179         TPM_UNDEFINED,          /* 165 */
 180         TPM_UNDEFINED,          /* 166 */
 181         TPM_UNDEFINED,          /* 167 */
 182         TPM_UNDEFINED,          /* 168 */
 183         TPM_UNDEFINED,          /* 169 */
 184         TPM_UNDEFINED,          /* 16a */
 185         TPM_UNDEFINED,          /* 16b */
 186         TPM_UNDEFINED,          /* 16c */
 187         TPM_UNDEFINED,          /* 16d */
 188         TPM_UNDEFINED,          /* 16e */
 189         TPM_UNDEFINED,          /* 16f */
 190         TPM_UNDEFINED,          /* 170 */
 191         TPM_UNDEFINED,          /* 171 */
 192         TPM_UNDEFINED,          /* 172 */
 193         TPM_UNDEFINED,          /* 173 */
 194         TPM_UNDEFINED,          /* 174 */
 195         TPM_UNDEFINED,          /* 175 */
 196         TPM_UNDEFINED,          /* 176 */
 197         TPM_LONG,               /* 177 */
 198         TPM_UNDEFINED,          /* 178 */
 199         TPM_UNDEFINED,          /* 179 */
 200         TPM_MEDIUM,             /* 17a */
 201         TPM_LONG,               /* 17b */
 202         TPM_UNDEFINED,          /* 17c */
 203         TPM_UNDEFINED,          /* 17d */
 204         TPM_UNDEFINED,          /* 17e */
 205         TPM_UNDEFINED,          /* 17f */
 206         TPM_UNDEFINED,          /* 180 */
 207         TPM_UNDEFINED,          /* 181 */
 208         TPM_MEDIUM,             /* 182 */
 209         TPM_UNDEFINED,          /* 183 */
 210         TPM_UNDEFINED,          /* 184 */
 211         TPM_MEDIUM,             /* 185 */
 212         TPM_MEDIUM,             /* 186 */
 213         TPM_UNDEFINED,          /* 187 */
 214         TPM_UNDEFINED,          /* 188 */
 215         TPM_UNDEFINED,          /* 189 */
 216         TPM_UNDEFINED,          /* 18a */
 217         TPM_UNDEFINED,          /* 18b */
 218         TPM_UNDEFINED,          /* 18c */
 219         TPM_UNDEFINED,          /* 18d */
 220         TPM_UNDEFINED,          /* 18e */
 221         TPM_UNDEFINED           /* 18f */
 222 };
 223
 224 #define TPM2_PCR_READ_IN_SIZE \
 225         (sizeof(struct tpm_input_header) + \
 226          sizeof(struct tpm2_pcr_read_in))
 227
 228 static const struct tpm_input_header tpm2_pcrread_header = {
 229         .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
 230         .length = cpu_to_be32(TPM2_PCR_READ_IN_SIZE),
 231         .ordinal = cpu_to_be32(TPM2_CC_PCR_READ)
 232 };
 233
 234 /**
 235  * tpm2_pcr_read() - read a PCR value
 236  * @chip:       TPM chip to use.
 237  * @pcr_idx:    index of the PCR to read.
 238  * @ref_buf:    buffer to store the resulting hash,
 239  *
 240  * 0 is returned when the operation is successful. If a negative number is
 241  * returned it remarks a POSIX error code. If a positive number is returned
 242  * it remarks a TPM error.
 243  */
 244 int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
 245 {
 246         int rc;
 247         struct tpm2_cmd cmd;
 248         u8 *buf;
 249
 250         if (pcr_idx >= TPM2_PLATFORM_PCR)
 251                 return -EINVAL;
 252
 253         cmd.header.in = tpm2_pcrread_header;
 254         cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
 255         cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
 256         cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
 257
 258         memset(cmd.params.pcrread_in.pcr_select, 0,
 259                sizeof(cmd.params.pcrread_in.pcr_select));
 260         cmd.params.pcrread_in.pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
 261
 262         rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
 263                               "attempting to read a pcr value");
 264         if (rc == 0) {
 265                 buf = cmd.params.pcrread_out.digest;
 266                 memcpy(res_buf, buf, TPM_DIGEST_SIZE);
 267         }
 268
 269         return rc;
 270 }
 271
 272 #define TPM2_GET_PCREXTEND_IN_SIZE \
 273         (sizeof(struct tpm_input_header) + \
 274          sizeof(struct tpm2_pcr_extend_in))
 275
 276 static const struct tpm_input_header tpm2_pcrextend_header = {
 277         .tag = cpu_to_be16(TPM2_ST_SESSIONS),
 278         .length = cpu_to_be32(TPM2_GET_PCREXTEND_IN_SIZE),
 279         .ordinal = cpu_to_be32(TPM2_CC_PCR_EXTEND)
 280 };
 281
 282 /**
 283  * tpm2_pcr_extend() - extend a PCR value
 284  * @chip:       TPM chip to use.
 285  * @pcr_idx:    index of the PCR.
 286  * @hash:       hash value to use for the extend operation.
 287  *
 288  * 0 is returned when the operation is successful. If a negative number is
 289  * returned it remarks a POSIX error code. If a positive number is returned
 290  * it remarks a TPM error.
 291  */
 292 int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
 293 {
 294         struct tpm2_cmd cmd;
 295         int rc;
 296
 297         cmd.header.in = tpm2_pcrextend_header;
 298         cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx);
 299         cmd.params.pcrextend_in.auth_area_size =
 300                 cpu_to_be32(sizeof(struct tpm2_null_auth_area));
 301         cmd.params.pcrextend_in.auth_area.handle =
 302                 cpu_to_be32(TPM2_RS_PW);
 303         cmd.params.pcrextend_in.auth_area.nonce_size = 0;
 304         cmd.params.pcrextend_in.auth_area.attributes = 0;
 305         cmd.params.pcrextend_in.auth_area.auth_size = 0;
 306         cmd.params.pcrextend_in.digest_cnt = cpu_to_be32(1);
 307         cmd.params.pcrextend_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
 308         memcpy(cmd.params.pcrextend_in.digest, hash, TPM_DIGEST_SIZE);
 309
 310         rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
 311                               "attempting extend a PCR value");
 312
 313         return rc;
 314 }
 315
 316 #define TPM2_GETRANDOM_IN_SIZE \
 317         (sizeof(struct tpm_input_header) + \
 318          sizeof(struct tpm2_get_random_in))
 319
 320 static const struct tpm_input_header tpm2_getrandom_header = {
 321         .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
 322         .length = cpu_to_be32(TPM2_GETRANDOM_IN_SIZE),
 323         .ordinal = cpu_to_be32(TPM2_CC_GET_RANDOM)
 324 };
 325
 326 /**
 327  * tpm2_get_random() - get random bytes from the TPM RNG
 328  * @chip: TPM chip to use
 329  * @out: destination buffer for the random bytes
 330  * @max: the max number of bytes to write to @out
 331  *
 332  * 0 is returned when the operation is successful. If a negative number is
 333  * returned it remarks a POSIX error code. If a positive number is returned
 334  * it remarks a TPM error.
 335  */
 336 int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 337 {
 338         struct tpm2_cmd cmd;
 339         u32 recd;
 340         u32 num_bytes;
 341         int err;
 342         int total = 0;
 343         int retries = 5;
 344         u8 *dest = out;
 345
 346         num_bytes = min_t(u32, max, sizeof(cmd.params.getrandom_out.buffer));
 347
 348         if (!out || !num_bytes ||
 349             max > sizeof(cmd.params.getrandom_out.buffer))
 350                 return -EINVAL;
 351
 352         do {
 353                 cmd.header.in = tpm2_getrandom_header;
 354                 cmd.params.getrandom_in.size = cpu_to_be16(num_bytes);
 355
 356                 err = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
 357                                        "attempting get random");
 358                 if (err)
 359                         break;
 360
 361                 recd = min_t(u32, be16_to_cpu(cmd.params.getrandom_out.size),
 362                              num_bytes);
 363                 memcpy(dest, cmd.params.getrandom_out.buffer, recd);
 364
 365                 dest += recd;
 366                 total += recd;
 367                 num_bytes -= recd;
 368         } while (retries-- && total < max);
 369
 370         return total ? total : -EIO;
 371 }
 372
 373 #define TPM2_GET_TPM_PT_IN_SIZE \
 374         (sizeof(struct tpm_input_header) + \
 375          sizeof(struct tpm2_get_tpm_pt_in))
 376
 377 static const struct tpm_input_header tpm2_get_tpm_pt_header = {
 378         .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
 379         .length = cpu_to_be32(TPM2_GET_TPM_PT_IN_SIZE),
 380         .ordinal = cpu_to_be32(TPM2_CC_GET_CAPABILITY)
 381 };
 382
 383 /**
 384  * tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
 385  * @chip:               TPM chip to use.
 386  * @property_id:        property ID.
 387  * @value:              output variable.
 388  * @desc:               passed to tpm_transmit_cmd()
 389  *
 390  * 0 is returned when the operation is successful. If a negative number is
 391  * returned it remarks a POSIX error code. If a positive number is returned
 392  * it remarks a TPM error.
 393  */
 394 ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
 395                         const char *desc)
 396 {
 397         struct tpm2_cmd cmd;
 398         int rc;
 399
 400         cmd.header.in = tpm2_get_tpm_pt_header;
 401         cmd.params.get_tpm_pt_in.cap_id = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES);
 402         cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(property_id);
 403         cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
 404
 405         rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), desc);
 406         if (!rc)
 407                 *value = cmd.params.get_tpm_pt_out.value;
 408
 409         return rc;
 410 }
 411
 412 #define TPM2_STARTUP_IN_SIZE \
 413         (sizeof(struct tpm_input_header) + \
 414          sizeof(struct tpm2_startup_in))
 415
 416 static const struct tpm_input_header tpm2_startup_header = {
 417         .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
 418         .length = cpu_to_be32(TPM2_STARTUP_IN_SIZE),
 419         .ordinal = cpu_to_be32(TPM2_CC_STARTUP)
 420 };
 421
 422 /**
 423  * tpm2_startup() - send startup command to the TPM chip
 424  * @chip:               TPM chip to use.
 425  * @startup_type        startup type. The value is either
 426  *                      TPM_SU_CLEAR or TPM_SU_STATE.
 427  *
 428  * 0 is returned when the operation is successful. If a negative number is
 429  * returned it remarks a POSIX error code. If a positive number is returned
 430  * it remarks a TPM error.
 431  */
 432 int tpm2_startup(struct tpm_chip *chip, u16 startup_type)
 433 {
 434         struct tpm2_cmd cmd;
 435
 436         cmd.header.in = tpm2_startup_header;
 437
 438         cmd.params.startup_in.startup_type = cpu_to_be16(startup_type);
 439         return tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
 440                                 "attempting to start the TPM");
 441 }
 442 EXPORT_SYMBOL_GPL(tpm2_startup);
 443
 444 #define TPM2_SHUTDOWN_IN_SIZE \
 445         (sizeof(struct tpm_input_header) + \
 446          sizeof(struct tpm2_startup_in))
 447
 448 static const struct tpm_input_header tpm2_shutdown_header = {
 449         .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
 450         .length = cpu_to_be32(TPM2_SHUTDOWN_IN_SIZE),
 451         .ordinal = cpu_to_be32(TPM2_CC_SHUTDOWN)
 452 };
 453
 454 /**
 455  * tpm2_shutdown() - send shutdown command to the TPM chip
 456  * @chip:               TPM chip to use.
 457  * @shutdown_type       shutdown type. The value is either
 458  *                      TPM_SU_CLEAR or TPM_SU_STATE.
 459  */
 460 void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 461 {
 462         struct tpm2_cmd cmd;
 463         int rc;
 464
 465         cmd.header.in = tpm2_shutdown_header;
 466         cmd.params.startup_in.startup_type = cpu_to_be16(shutdown_type);
 467
 468         rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), "stopping the TPM");
 469
 470         /* In places where shutdown command is sent there's no much we can do
 471          * except print the error code on a system failure.
 472          */
 473         if (rc < 0)
 474                 dev_warn(chip->pdev, "transmit returned %d while stopping the TPM",
 475                          rc);
 476 }
 477 EXPORT_SYMBOL_GPL(tpm2_shutdown);
 478
 479 /*
 480  * tpm2_calc_ordinal_duration() - maximum duration for a command
 481  * @chip:       TPM chip to use.
 482  * @ordinal:    command code number.
 483  *
 484  * 0 is returned when the operation is successful. If a negative number is
 485  * returned it remarks a POSIX error code. If a positive number is returned
 486  * it remarks a TPM error.
 487  */
 488 unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
 489 {
 490         int index = TPM_UNDEFINED;
 491         int duration = 0;
 492
 493         if (ordinal >= TPM2_CC_FIRST && ordinal <= TPM2_CC_LAST)
 494                 index = tpm2_ordinal_duration[ordinal - TPM2_CC_FIRST];
 495
 496         if (index != TPM_UNDEFINED)
 497                 duration = chip->vendor.duration[index];
 498
 499         if (duration <= 0)
 500                 duration = 2 * 60 * HZ;
 501
 502         return duration;
 503 }
 504 EXPORT_SYMBOL_GPL(tpm2_calc_ordinal_duration);
 505
 506 #define TPM2_SELF_TEST_IN_SIZE \
 507         (sizeof(struct tpm_input_header) + \
 508          sizeof(struct tpm2_self_test_in))
 509
 510 static const struct tpm_input_header tpm2_selftest_header = {
 511         .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
 512         .length = cpu_to_be32(TPM2_SELF_TEST_IN_SIZE),
 513         .ordinal = cpu_to_be32(TPM2_CC_SELF_TEST)
 514 };
 515
 516 /**
 517  * tpm2_continue_selftest() - start a self test
 518  * @chip: TPM chip to use
 519  * @full: test all commands instead of testing only those that were not
 520  *        previously tested.
 521  *
 522  * 0 is returned when the operation is successful. If a negative number is
 523  * returned it remarks a POSIX error code. If a positive number is returned
 524  * it remarks a TPM error.
 525  */
 526 static int tpm2_start_selftest(struct tpm_chip *chip, bool full)
 527 {
 528         int rc;
 529         struct tpm2_cmd cmd;
 530
 531         cmd.header.in = tpm2_selftest_header;
 532         cmd.params.selftest_in.full_test = full;
 533
 534         rc = tpm_transmit_cmd(chip, &cmd, TPM2_SELF_TEST_IN_SIZE,
 535                               "continue selftest");
 536
 537         /* At least some prototype chips seem to give RC_TESTING error
 538          * immediately. This is a workaround for that.
 539          */
 540         if (rc == TPM2_RC_TESTING) {
 541                 dev_warn(chip->pdev, "Got RC_TESTING, ignoring\n");
 542                 rc = 0;
 543         }
 544
 545         return rc;
 546 }
 547
 548 /**
 549  * tpm2_do_selftest() - run a full self test
 550  * @chip: TPM chip to use
 551  *
 552  * During the self test TPM2 commands return with the error code RC_TESTING.
 553  * Waiting is done by issuing PCR read until it executes successfully.
 554  *
 555  * 0 is returned when the operation is successful. If a negative number is
 556  * returned it remarks a POSIX error code. If a positive number is returned
 557  * it remarks a TPM error.
 558  */
 559 int tpm2_do_selftest(struct tpm_chip *chip)
 560 {
 561         int rc;
 562         unsigned int loops;
 563         unsigned int delay_msec = 100;
 564         unsigned long duration;
 565         struct tpm2_cmd cmd;
 566         int i;
 567
 568         duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
 569
 570         loops = jiffies_to_msecs(duration) / delay_msec;
 571
 572         rc = tpm2_start_selftest(chip, true);
 573         if (rc)
 574                 return rc;
 575
 576         for (i = 0; i < loops; i++) {
 577                 /* Attempt to read a PCR value */
 578                 cmd.header.in = tpm2_pcrread_header;
 579                 cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
 580                 cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
 581                 cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
 582                 cmd.params.pcrread_in.pcr_select[0] = 0x01;
 583                 cmd.params.pcrread_in.pcr_select[1] = 0x00;
 584                 cmd.params.pcrread_in.pcr_select[2] = 0x00;
 585
 586                 rc = tpm_transmit_cmd(chip, (u8 *) &cmd, sizeof(cmd), NULL);
 587                 if (rc < 0)
 588                         break;
 589
 590                 rc = be32_to_cpu(cmd.header.out.return_code);
 591                 if (rc != TPM2_RC_TESTING)
 592                         break;
 593
 594                 msleep(delay_msec);
 595         }
 596
 597         return rc;
 598 }
 599 EXPORT_SYMBOL_GPL(tpm2_do_selftest);
 600
 601 /**
 602  * tpm2_gen_interrupt() - generate an interrupt
 603  * @chip: TPM chip to use
 604  *
 605  * 0 is returned when the operation is successful. If a negative number is
 606  * returned it remarks a POSIX error code. If a positive number is returned
 607  * it remarks a TPM error.
 608  */
 609 int tpm2_gen_interrupt(struct tpm_chip *chip)
 610 {
 611         u32 dummy;
 612
 613         return tpm2_get_tpm_pt(chip, 0x100, &dummy,
 614                                "attempting to generate an interrupt");
 615 }
 616 EXPORT_SYMBOL_GPL(tpm2_gen_interrupt);
 617
 618 /**
 619  * tpm2_probe() - probe TPM 2.0
 620  * @chip: TPM chip to use
 621  *
 622  * Send idempotent TPM 2.0 command and see whether TPM 2.0 chip replied based on
 623  * the reply tag.
 624  */
 625 int tpm2_probe(struct tpm_chip *chip)
 626 {
 627         struct tpm2_cmd cmd;
 628         int rc;
 629
 630         cmd.header.in = tpm2_get_tpm_pt_header;
 631         cmd.params.get_tpm_pt_in.cap_id = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES);
 632         cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(0x100);
 633         cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
 634
 635         rc = tpm_transmit(chip, (const char *) &cmd, sizeof(cmd));
 636         if (rc <  0)
 637                 return rc;
 638         else if (rc < TPM_HEADER_SIZE)
 639                 return -EFAULT;
 640
 641         if (be16_to_cpu(cmd.header.out.tag) == TPM2_ST_NO_SESSIONS)
 642                 chip->flags |= TPM_CHIP_FLAG_TPM2;
 643
 644         return 0;
 645 }
 646 EXPORT_SYMBOL_GPL(tpm2_probe);