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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2004 IBM Corporation4 * Copyright (C) 2014 Intel Corporation5 *6 * Authors:7 * Leendert van Doorn <leendert@watson.ibm.com>8 * Dave Safford <safford@watson.ibm.com>9 * Reiner Sailer <sailer@watson.ibm.com>10 * Kylene Hall <kjhall@us.ibm.com>11 *12 * Maintained by: <tpmdd-devel@lists.sourceforge.net>13 *14 * Device driver for TCG/TCPA TPM (trusted platform module).15 * Specifications at www.trustedcomputinggroup.org16 *17 * Note, the TPM chip is not interrupt driven (only polling)18 * and can have very long timeouts (minutes!). Hence the unusual19 * calls to msleep.20 */21 22#include <linux/poll.h>23#include <linux/slab.h>24#include <linux/mutex.h>25#include <linux/spinlock.h>26#include <linux/suspend.h>27#include <linux/freezer.h>28#include <linux/tpm_eventlog.h>29 30#include "tpm.h"31 32/*33 * Bug workaround - some TPM's don't flush the most34 * recently changed pcr on suspend, so force the flush35 * with an extend to the selected _unused_ non-volatile pcr.36 */37static u32 tpm_suspend_pcr;38module_param_named(suspend_pcr, tpm_suspend_pcr, uint, 0644);39MODULE_PARM_DESC(suspend_pcr,40 "PCR to use for dummy writes to facilitate flush on suspend.");41 42/**43 * tpm_calc_ordinal_duration() - calculate the maximum command duration44 * @chip: TPM chip to use.45 * @ordinal: TPM command ordinal.46 *47 * The function returns the maximum amount of time the chip could take48 * to return the result for a particular ordinal in jiffies.49 *50 * Return: A maximal duration time for an ordinal in jiffies.51 */52unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)53{54 if (chip->flags & TPM_CHIP_FLAG_TPM2)55 return tpm2_calc_ordinal_duration(chip, ordinal);56 else57 return tpm1_calc_ordinal_duration(chip, ordinal);58}59EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);60 61static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz)62{63 struct tpm_header *header = buf;64 int rc;65 ssize_t len = 0;66 u32 count, ordinal;67 unsigned long stop;68 69 if (bufsiz < TPM_HEADER_SIZE)70 return -EINVAL;71 72 if (bufsiz > TPM_BUFSIZE)73 bufsiz = TPM_BUFSIZE;74 75 count = be32_to_cpu(header->length);76 ordinal = be32_to_cpu(header->ordinal);77 if (count == 0)78 return -ENODATA;79 if (count > bufsiz) {80 dev_err(&chip->dev,81 "invalid count value %x %zx\n", count, bufsiz);82 return -E2BIG;83 }84 85 rc = chip->ops->send(chip, buf, count);86 if (rc < 0) {87 if (rc != -EPIPE)88 dev_err(&chip->dev,89 "%s: send(): error %d\n", __func__, rc);90 return rc;91 }92 93 /* A sanity check. send() should just return zero on success e.g.94 * not the command length.95 */96 if (rc > 0) {97 dev_warn(&chip->dev,98 "%s: send(): invalid value %d\n", __func__, rc);99 rc = 0;100 }101 102 if (chip->flags & TPM_CHIP_FLAG_IRQ)103 goto out_recv;104 105 stop = jiffies + tpm_calc_ordinal_duration(chip, ordinal);106 do {107 u8 status = chip->ops->status(chip);108 if ((status & chip->ops->req_complete_mask) ==109 chip->ops->req_complete_val)110 goto out_recv;111 112 if (chip->ops->req_canceled(chip, status)) {113 dev_err(&chip->dev, "Operation Canceled\n");114 return -ECANCELED;115 }116 117 tpm_msleep(TPM_TIMEOUT_POLL);118 rmb();119 } while (time_before(jiffies, stop));120 121 chip->ops->cancel(chip);122 dev_err(&chip->dev, "Operation Timed out\n");123 return -ETIME;124 125out_recv:126 len = chip->ops->recv(chip, buf, bufsiz);127 if (len < 0) {128 rc = len;129 dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc);130 } else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))131 rc = -EFAULT;132 133 return rc ? rc : len;134}135 136/**137 * tpm_transmit - Internal kernel interface to transmit TPM commands.138 * @chip: a TPM chip to use139 * @buf: a TPM command buffer140 * @bufsiz: length of the TPM command buffer141 *142 * A wrapper around tpm_try_transmit() that handles TPM2_RC_RETRY returns from143 * the TPM and retransmits the command after a delay up to a maximum wait of144 * TPM2_DURATION_LONG.145 *146 * Note that TPM 1.x never returns TPM2_RC_RETRY so the retry logic is TPM 2.0147 * only.148 *149 * Return:150 * * The response length - OK151 * * -errno - A system error152 */153ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz)154{155 struct tpm_header *header = (struct tpm_header *)buf;156 /* space for header and handles */157 u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];158 unsigned int delay_msec = TPM2_DURATION_SHORT;159 u32 rc = 0;160 ssize_t ret;161 const size_t save_size = min(sizeof(save), bufsiz);162 /* the command code is where the return code will be */163 u32 cc = be32_to_cpu(header->return_code);164 165 /*166 * Subtlety here: if we have a space, the handles will be167 * transformed, so when we restore the header we also have to168 * restore the handles.169 */170 memcpy(save, buf, save_size);171 172 for (;;) {173 ret = tpm_try_transmit(chip, buf, bufsiz);174 if (ret < 0)175 break;176 rc = be32_to_cpu(header->return_code);177 if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)178 break;179 /*180 * return immediately if self test returns test181 * still running to shorten boot time.182 */183 if (rc == TPM2_RC_TESTING && cc == TPM2_CC_SELF_TEST)184 break;185 186 if (delay_msec > TPM2_DURATION_LONG) {187 if (rc == TPM2_RC_RETRY)188 dev_err(&chip->dev, "in retry loop\n");189 else190 dev_err(&chip->dev,191 "self test is still running\n");192 break;193 }194 tpm_msleep(delay_msec);195 delay_msec *= 2;196 memcpy(buf, save, save_size);197 }198 return ret;199}200 201/**202 * tpm_transmit_cmd - send a tpm command to the device203 * @chip: a TPM chip to use204 * @buf: a TPM command buffer205 * @min_rsp_body_length: minimum expected length of response body206 * @desc: command description used in the error message207 *208 * Return:209 * * 0 - OK210 * * -errno - A system error211 * * TPM_RC - A TPM error212 */213ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,214 size_t min_rsp_body_length, const char *desc)215{216 const struct tpm_header *header = (struct tpm_header *)buf->data;217 int err;218 ssize_t len;219 220 len = tpm_transmit(chip, buf->data, PAGE_SIZE);221 if (len < 0)222 return len;223 224 err = be32_to_cpu(header->return_code);225 if (err != 0 && err != TPM_ERR_DISABLED && err != TPM_ERR_DEACTIVATED226 && err != TPM2_RC_TESTING && desc)227 dev_err(&chip->dev, "A TPM error (%d) occurred %s\n", err,228 desc);229 if (err)230 return err;231 232 if (len < min_rsp_body_length + TPM_HEADER_SIZE)233 return -EFAULT;234 235 buf->length = len;236 return 0;237}238EXPORT_SYMBOL_GPL(tpm_transmit_cmd);239 240int tpm_get_timeouts(struct tpm_chip *chip)241{242 if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)243 return 0;244 245 if (chip->flags & TPM_CHIP_FLAG_TPM2)246 return tpm2_get_timeouts(chip);247 else248 return tpm1_get_timeouts(chip);249}250EXPORT_SYMBOL_GPL(tpm_get_timeouts);251 252/**253 * tpm_is_tpm2 - do we a have a TPM2 chip?254 * @chip: a &struct tpm_chip instance, %NULL for the default chip255 *256 * Return:257 * 1 if we have a TPM2 chip.258 * 0 if we don't have a TPM2 chip.259 * A negative number for system errors (errno).260 */261int tpm_is_tpm2(struct tpm_chip *chip)262{263 int rc;264 265 chip = tpm_find_get_ops(chip);266 if (!chip)267 return -ENODEV;268 269 rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;270 271 tpm_put_ops(chip);272 273 return rc;274}275EXPORT_SYMBOL_GPL(tpm_is_tpm2);276 277/**278 * tpm_pcr_read - read a PCR value from SHA1 bank279 * @chip: a &struct tpm_chip instance, %NULL for the default chip280 * @pcr_idx: the PCR to be retrieved281 * @digest: the PCR bank and buffer current PCR value is written to282 *283 * Return: same as with tpm_transmit_cmd()284 */285int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,286 struct tpm_digest *digest)287{288 int rc;289 290 chip = tpm_find_get_ops(chip);291 if (!chip)292 return -ENODEV;293 294 if (chip->flags & TPM_CHIP_FLAG_TPM2)295 rc = tpm2_pcr_read(chip, pcr_idx, digest, NULL);296 else297 rc = tpm1_pcr_read(chip, pcr_idx, digest->digest);298 299 tpm_put_ops(chip);300 return rc;301}302EXPORT_SYMBOL_GPL(tpm_pcr_read);303 304/**305 * tpm_pcr_extend - extend a PCR value in SHA1 bank.306 * @chip: a &struct tpm_chip instance, %NULL for the default chip307 * @pcr_idx: the PCR to be retrieved308 * @digests: array of tpm_digest structures used to extend PCRs309 *310 * Note: callers must pass a digest for every allocated PCR bank, in the same311 * order of the banks in chip->allocated_banks.312 *313 * Return: same as with tpm_transmit_cmd()314 */315int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,316 struct tpm_digest *digests)317{318 int rc;319 int i;320 321 chip = tpm_find_get_ops(chip);322 if (!chip)323 return -ENODEV;324 325 for (i = 0; i < chip->nr_allocated_banks; i++) {326 if (digests[i].alg_id != chip->allocated_banks[i].alg_id) {327 rc = -EINVAL;328 goto out;329 }330 }331 332 if (chip->flags & TPM_CHIP_FLAG_TPM2) {333 rc = tpm2_pcr_extend(chip, pcr_idx, digests);334 goto out;335 }336 337 rc = tpm1_pcr_extend(chip, pcr_idx, digests[0].digest,338 "attempting extend a PCR value");339 340out:341 tpm_put_ops(chip);342 return rc;343}344EXPORT_SYMBOL_GPL(tpm_pcr_extend);345 346int tpm_auto_startup(struct tpm_chip *chip)347{348 int rc;349 350 if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP))351 return 0;352 353 if (chip->flags & TPM_CHIP_FLAG_TPM2)354 rc = tpm2_auto_startup(chip);355 else356 rc = tpm1_auto_startup(chip);357 358 return rc;359}360 361/*362 * We are about to suspend. Save the TPM state363 * so that it can be restored.364 */365int tpm_pm_suspend(struct device *dev)366{367 struct tpm_chip *chip = dev_get_drvdata(dev);368 int rc = 0;369 370 if (!chip)371 return -ENODEV;372 373 rc = tpm_try_get_ops(chip);374 if (rc) {375 /* Can be safely set out of locks, as no action cannot race: */376 chip->flags |= TPM_CHIP_FLAG_SUSPENDED;377 goto out;378 }379 380 if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)381 goto suspended;382 383 if ((chip->flags & TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED) &&384 !pm_suspend_via_firmware())385 goto suspended;386 387 if (chip->flags & TPM_CHIP_FLAG_TPM2) {388 tpm2_end_auth_session(chip);389 tpm2_shutdown(chip, TPM2_SU_STATE);390 goto suspended;391 }392 393 rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);394 395suspended:396 chip->flags |= TPM_CHIP_FLAG_SUSPENDED;397 tpm_put_ops(chip);398 399out:400 if (rc)401 dev_err(dev, "Ignoring error %d while suspending\n", rc);402 return 0;403}404EXPORT_SYMBOL_GPL(tpm_pm_suspend);405 406/*407 * Resume from a power safe. The BIOS already restored408 * the TPM state.409 */410int tpm_pm_resume(struct device *dev)411{412 struct tpm_chip *chip = dev_get_drvdata(dev);413 414 if (chip == NULL)415 return -ENODEV;416 417 chip->flags &= ~TPM_CHIP_FLAG_SUSPENDED;418 419 /*420 * Guarantee that SUSPENDED is written last, so that hwrng does not421 * activate before the chip has been fully resumed.422 */423 wmb();424 425 return 0;426}427EXPORT_SYMBOL_GPL(tpm_pm_resume);428 429/**430 * tpm_get_random() - get random bytes from the TPM's RNG431 * @chip: a &struct tpm_chip instance, %NULL for the default chip432 * @out: destination buffer for the random bytes433 * @max: the max number of bytes to write to @out434 *435 * Return: number of random bytes read or a negative error value.436 */437int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)438{439 int rc;440 441 if (!out || max > TPM_MAX_RNG_DATA)442 return -EINVAL;443 444 chip = tpm_find_get_ops(chip);445 if (!chip)446 return -ENODEV;447 448 /* Give back zero bytes, as TPM chip has not yet fully resumed: */449 if (chip->flags & TPM_CHIP_FLAG_SUSPENDED) {450 rc = 0;451 goto out;452 }453 454 if (chip->flags & TPM_CHIP_FLAG_TPM2)455 rc = tpm2_get_random(chip, out, max);456 else457 rc = tpm1_get_random(chip, out, max);458 459out:460 tpm_put_ops(chip);461 return rc;462}463EXPORT_SYMBOL_GPL(tpm_get_random);464 465static int __init tpm_init(void)466{467 int rc;468 469 rc = class_register(&tpm_class);470 if (rc) {471 pr_err("couldn't create tpm class\n");472 return rc;473 }474 475 rc = class_register(&tpmrm_class);476 if (rc) {477 pr_err("couldn't create tpmrm class\n");478 goto out_destroy_tpm_class;479 }480 481 rc = alloc_chrdev_region(&tpm_devt, 0, 2*TPM_NUM_DEVICES, "tpm");482 if (rc < 0) {483 pr_err("tpm: failed to allocate char dev region\n");484 goto out_destroy_tpmrm_class;485 }486 487 rc = tpm_dev_common_init();488 if (rc) {489 pr_err("tpm: failed to allocate char dev region\n");490 goto out_unreg_chrdev;491 }492 493 return 0;494 495out_unreg_chrdev:496 unregister_chrdev_region(tpm_devt, 2 * TPM_NUM_DEVICES);497out_destroy_tpmrm_class:498 class_unregister(&tpmrm_class);499out_destroy_tpm_class:500 class_unregister(&tpm_class);501 502 return rc;503}504 505static void __exit tpm_exit(void)506{507 idr_destroy(&dev_nums_idr);508 class_unregister(&tpm_class);509 class_unregister(&tpmrm_class);510 unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);511 tpm_dev_common_exit();512}513 514subsys_initcall(tpm_init);515module_exit(tpm_exit);516 517MODULE_AUTHOR("Leendert van Doorn <leendert@watson.ibm.com>");518MODULE_DESCRIPTION("TPM Driver");519MODULE_VERSION("2.0");520MODULE_LICENSE("GPL");521