1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2004 IBM Corporation
4 * Copyright (C) 2014 Intel Corporation
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>
13 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
15 * TPM chip management routines.
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>
28 DEFINE_IDR(dev_nums_idr);
29 static DEFINE_MUTEX(idr_lock);
31 struct class *tpm_class;
32 struct class *tpmrm_class;
35 static int tpm_request_locality(struct tpm_chip *chip)
39 if (!chip->ops->request_locality)
42 rc = chip->ops->request_locality(chip, 0);
50 static void tpm_relinquish_locality(struct tpm_chip *chip)
54 if (!chip->ops->relinquish_locality)
57 rc = chip->ops->relinquish_locality(chip, chip->locality);
59 dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
64 static int tpm_cmd_ready(struct tpm_chip *chip)
66 if (!chip->ops->cmd_ready)
69 return chip->ops->cmd_ready(chip);
72 static int tpm_go_idle(struct tpm_chip *chip)
74 if (!chip->ops->go_idle)
77 return chip->ops->go_idle(chip);
80 static void tpm_clk_enable(struct tpm_chip *chip)
82 if (chip->ops->clk_enable)
83 chip->ops->clk_enable(chip, true);
86 static void tpm_clk_disable(struct tpm_chip *chip)
88 if (chip->ops->clk_enable)
89 chip->ops->clk_enable(chip, false);
93 * tpm_chip_start() - power on the TPM
94 * @chip: a TPM chip to use
97 * * The response length - OK
98 * * -errno - A system error
100 int tpm_chip_start(struct tpm_chip *chip)
104 tpm_clk_enable(chip);
106 if (chip->locality == -1) {
107 ret = tpm_request_locality(chip);
109 tpm_clk_disable(chip);
114 ret = tpm_cmd_ready(chip);
116 tpm_relinquish_locality(chip);
117 tpm_clk_disable(chip);
123 EXPORT_SYMBOL_GPL(tpm_chip_start);
126 * tpm_chip_stop() - power off the TPM
127 * @chip: a TPM chip to use
130 * * The response length - OK
131 * * -errno - A system error
133 void tpm_chip_stop(struct tpm_chip *chip)
136 tpm_relinquish_locality(chip);
137 tpm_clk_disable(chip);
139 EXPORT_SYMBOL_GPL(tpm_chip_stop);
142 * tpm_try_get_ops() - Get a ref to the tpm_chip
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.
150 * Returns -ERRNO if the chip could not be got.
152 int tpm_try_get_ops(struct tpm_chip *chip)
156 get_device(&chip->dev);
158 down_read(&chip->ops_sem);
162 mutex_lock(&chip->tpm_mutex);
163 rc = tpm_chip_start(chip);
169 mutex_unlock(&chip->tpm_mutex);
171 up_read(&chip->ops_sem);
172 put_device(&chip->dev);
175 EXPORT_SYMBOL_GPL(tpm_try_get_ops);
178 * tpm_put_ops() - Release a ref to the tpm_chip
181 * This is the opposite pair to tpm_try_get_ops(). After this returns chip may
184 void tpm_put_ops(struct tpm_chip *chip)
187 mutex_unlock(&chip->tpm_mutex);
188 up_read(&chip->ops_sem);
189 put_device(&chip->dev);
191 EXPORT_SYMBOL_GPL(tpm_put_ops);
194 * tpm_default_chip() - find a TPM chip and get a reference to it
196 struct tpm_chip *tpm_default_chip(void)
198 struct tpm_chip *chip, *res = NULL;
202 mutex_lock(&idr_lock);
205 chip_prev = chip_num;
206 chip = idr_get_next(&dev_nums_idr, &chip_num);
208 get_device(&chip->dev);
212 } while (chip_prev != chip_num);
214 mutex_unlock(&idr_lock);
218 EXPORT_SYMBOL_GPL(tpm_default_chip);
221 * tpm_find_get_ops() - find and reserve a TPM chip
222 * @chip: a &struct tpm_chip instance, %NULL for the default chip
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
231 * A reserved &struct tpm_chip instance.
232 * %NULL if a chip is not found.
233 * %NULL if the chip is not available.
235 struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip)
240 if (!tpm_try_get_ops(chip))
245 chip = tpm_default_chip();
248 rc = tpm_try_get_ops(chip);
249 /* release additional reference we got from tpm_default_chip() */
250 put_device(&chip->dev);
257 * tpm_dev_release() - free chip memory and the device number
258 * @dev: the character device for the TPM chip
260 * This is used as the release function for the character device.
262 static void tpm_dev_release(struct device *dev)
264 struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
266 mutex_lock(&idr_lock);
267 idr_remove(&dev_nums_idr, chip->dev_num);
268 mutex_unlock(&idr_lock);
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);
278 * tpm_class_shutdown() - prepare the TPM device for loss of power.
279 * @dev: device to which the chip is associated.
281 * Issues a TPM2_Shutdown command prior to loss of power, as required by the
282 * TPM 2.0 spec. Then, calls bus- and device- specific shutdown code.
284 * Return: always 0 (i.e. success)
286 static int tpm_class_shutdown(struct device *dev)
288 struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
290 down_write(&chip->ops_sem);
291 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
292 if (!tpm_chip_start(chip)) {
293 tpm2_shutdown(chip, TPM2_SU_CLEAR);
298 up_write(&chip->ops_sem);
304 * tpm_chip_alloc() - allocate a new struct tpm_chip instance
305 * @pdev: device to which the chip is associated
306 * At this point pdev mst be initialized, but does not have to
308 * @ops: struct tpm_class_ops instance
310 * Allocates a new struct tpm_chip instance and assigns a free
311 * device number for it. Must be paired with put_device(&chip->dev).
313 struct tpm_chip *tpm_chip_alloc(struct device *pdev,
314 const struct tpm_class_ops *ops)
316 struct tpm_chip *chip;
319 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
321 return ERR_PTR(-ENOMEM);
323 mutex_init(&chip->tpm_mutex);
324 init_rwsem(&chip->ops_sem);
328 mutex_lock(&idr_lock);
329 rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
330 mutex_unlock(&idr_lock);
332 dev_err(pdev, "No available tpm device numbers\n");
338 device_initialize(&chip->dev);
340 chip->dev.class = tpm_class;
341 chip->dev.class->shutdown_pre = tpm_class_shutdown;
342 chip->dev.release = tpm_dev_release;
343 chip->dev.parent = pdev;
344 chip->dev.groups = chip->groups;
346 if (chip->dev_num == 0)
347 chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
349 chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
351 rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
356 chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
358 cdev_init(&chip->cdev, &tpm_fops);
359 chip->cdev.owner = THIS_MODULE;
361 rc = tpm2_init_space(&chip->work_space, TPM2_SPACE_BUFFER_SIZE);
371 put_device(&chip->dev);
374 EXPORT_SYMBOL_GPL(tpm_chip_alloc);
377 * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
378 * @pdev: parent device to which the chip is associated
379 * @ops: struct tpm_class_ops instance
381 * Same as tpm_chip_alloc except devm is used to do the put_device
383 struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
384 const struct tpm_class_ops *ops)
386 struct tpm_chip *chip;
389 chip = tpm_chip_alloc(pdev, ops);
393 rc = devm_add_action_or_reset(pdev,
394 (void (*)(void *)) put_device,
399 dev_set_drvdata(pdev, chip);
403 EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
405 static int tpm_add_char_device(struct tpm_chip *chip)
409 rc = cdev_device_add(&chip->cdev, &chip->dev);
412 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
413 dev_name(&chip->dev), MAJOR(chip->dev.devt),
414 MINOR(chip->dev.devt), rc);
418 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
419 rc = tpm_devs_add(chip);
424 /* Make the chip available. */
425 mutex_lock(&idr_lock);
426 idr_replace(&dev_nums_idr, chip, chip->dev_num);
427 mutex_unlock(&idr_lock);
432 cdev_device_del(&chip->cdev, &chip->dev);
436 static void tpm_del_char_device(struct tpm_chip *chip)
438 cdev_device_del(&chip->cdev, &chip->dev);
440 /* Make the chip unavailable. */
441 mutex_lock(&idr_lock);
442 idr_replace(&dev_nums_idr, NULL, chip->dev_num);
443 mutex_unlock(&idr_lock);
445 /* Make the driver uncallable. */
446 down_write(&chip->ops_sem);
447 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
448 if (!tpm_chip_start(chip)) {
449 tpm2_shutdown(chip, TPM2_SU_CLEAR);
454 up_write(&chip->ops_sem);
457 static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
459 struct attribute **i;
461 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
464 sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
466 for (i = chip->groups[0]->attrs; *i != NULL; ++i)
467 sysfs_remove_link(&chip->dev.parent->kobj, (*i)->name);
470 /* For compatibility with legacy sysfs paths we provide symlinks from the
471 * parent dev directory to selected names within the tpm chip directory. Old
472 * kernel versions created these files directly under the parent.
474 static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
476 struct attribute **i;
479 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
482 rc = compat_only_sysfs_link_entry_to_kobj(
483 &chip->dev.parent->kobj, &chip->dev.kobj, "ppi", NULL);
484 if (rc && rc != -ENOENT)
487 /* All the names from tpm-sysfs */
488 for (i = chip->groups[0]->attrs; *i != NULL; ++i) {
489 rc = compat_only_sysfs_link_entry_to_kobj(
490 &chip->dev.parent->kobj, &chip->dev.kobj, (*i)->name, NULL);
492 tpm_del_legacy_sysfs(chip);
500 static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
502 struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng);
504 return tpm_get_random(chip, data, max);
507 static int tpm_add_hwrng(struct tpm_chip *chip)
509 if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
512 snprintf(chip->hwrng_name, sizeof(chip->hwrng_name),
513 "tpm-rng-%d", chip->dev_num);
514 chip->hwrng.name = chip->hwrng_name;
515 chip->hwrng.read = tpm_hwrng_read;
516 return hwrng_register(&chip->hwrng);
519 static int tpm_get_pcr_allocation(struct tpm_chip *chip)
523 rc = (chip->flags & TPM_CHIP_FLAG_TPM2) ?
524 tpm2_get_pcr_allocation(chip) :
525 tpm1_get_pcr_allocation(chip);
534 * tpm_chip_register() - create a character device for the TPM chip
535 * @chip: TPM chip to use.
537 * Creates a character device for the TPM chip and adds sysfs attributes for
538 * the device. As the last step this function adds the chip to the list of TPM
539 * chips available for in-kernel use.
541 * This function should be only called after the chip initialization is
544 int tpm_chip_register(struct tpm_chip *chip)
548 rc = tpm_chip_start(chip);
551 rc = tpm_auto_startup(chip);
557 rc = tpm_get_pcr_allocation(chip);
562 tpm_sysfs_add_device(chip);
564 tpm_bios_log_setup(chip);
568 rc = tpm_add_hwrng(chip);
572 rc = tpm_add_char_device(chip);
576 rc = tpm_add_legacy_sysfs(chip);
578 tpm_chip_unregister(chip);
585 if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
586 hwrng_unregister(&chip->hwrng);
588 tpm_bios_log_teardown(chip);
592 EXPORT_SYMBOL_GPL(tpm_chip_register);
595 * tpm_chip_unregister() - release the TPM driver
596 * @chip: TPM chip to use.
598 * Takes the chip first away from the list of available TPM chips and then
599 * cleans up all the resources reserved by tpm_chip_register().
601 * Once this function returns the driver call backs in 'op's will not be
602 * running and will no longer start.
604 * NOTE: This function should be only called before deinitializing chip
607 void tpm_chip_unregister(struct tpm_chip *chip)
609 tpm_del_legacy_sysfs(chip);
610 if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
611 hwrng_unregister(&chip->hwrng);
612 tpm_bios_log_teardown(chip);
613 if (chip->flags & TPM_CHIP_FLAG_TPM2)
614 tpm_devs_remove(chip);
615 tpm_del_char_device(chip);
617 EXPORT_SYMBOL_GPL(tpm_chip_unregister);