2 * Copyright (C) 2004 IBM Corporation
3 * Copyright (C) 2014 Intel Corporation
6 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
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>
12 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
14 * TPM chip management routines.
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License as
18 * published by the Free Software Foundation, version 2 of the
23 #include <linux/poll.h>
24 #include <linux/slab.h>
25 #include <linux/mutex.h>
26 #include <linux/spinlock.h>
27 #include <linux/freezer.h>
28 #include <linux/major.h>
29 #include <linux/tpm_eventlog.h>
30 #include <linux/hw_random.h>
33 DEFINE_IDR(dev_nums_idr);
34 static DEFINE_MUTEX(idr_lock);
36 struct class *tpm_class;
37 struct class *tpmrm_class;
41 * tpm_try_get_ops() - Get a ref to the tpm_chip
44 * The caller must already have some kind of locking to ensure that chip is
45 * valid. This function will lock the chip so that the ops member can be
46 * accessed safely. The locking prevents tpm_chip_unregister from
47 * completing, so it should not be held for long periods.
49 * Returns -ERRNO if the chip could not be got.
51 int tpm_try_get_ops(struct tpm_chip *chip)
55 get_device(&chip->dev);
57 down_read(&chip->ops_sem);
63 up_read(&chip->ops_sem);
64 put_device(&chip->dev);
67 EXPORT_SYMBOL_GPL(tpm_try_get_ops);
70 * tpm_put_ops() - Release a ref to the tpm_chip
73 * This is the opposite pair to tpm_try_get_ops(). After this returns chip may
76 void tpm_put_ops(struct tpm_chip *chip)
78 up_read(&chip->ops_sem);
79 put_device(&chip->dev);
81 EXPORT_SYMBOL_GPL(tpm_put_ops);
84 * tpm_default_chip() - find a TPM chip and get a reference to it
86 struct tpm_chip *tpm_default_chip(void)
88 struct tpm_chip *chip, *res = NULL;
92 mutex_lock(&idr_lock);
96 chip = idr_get_next(&dev_nums_idr, &chip_num);
98 get_device(&chip->dev);
102 } while (chip_prev != chip_num);
104 mutex_unlock(&idr_lock);
108 EXPORT_SYMBOL_GPL(tpm_default_chip);
111 * tpm_find_get_ops() - find and reserve a TPM chip
112 * @chip: a &struct tpm_chip instance, %NULL for the default chip
114 * Finds a TPM chip and reserves its class device and operations. The chip must
115 * be released with tpm_put_ops() after use.
116 * This function is for internal use only. It supports existing TPM callers
117 * by accepting NULL, but those callers should be converted to pass in a chip
121 * A reserved &struct tpm_chip instance.
122 * %NULL if a chip is not found.
123 * %NULL if the chip is not available.
125 struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip)
130 if (!tpm_try_get_ops(chip))
135 chip = tpm_default_chip();
138 rc = tpm_try_get_ops(chip);
139 /* release additional reference we got from tpm_default_chip() */
140 put_device(&chip->dev);
147 * tpm_dev_release() - free chip memory and the device number
148 * @dev: the character device for the TPM chip
150 * This is used as the release function for the character device.
152 static void tpm_dev_release(struct device *dev)
154 struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
156 mutex_lock(&idr_lock);
157 idr_remove(&dev_nums_idr, chip->dev_num);
158 mutex_unlock(&idr_lock);
160 kfree(chip->log.bios_event_log);
161 kfree(chip->work_space.context_buf);
162 kfree(chip->work_space.session_buf);
166 static void tpm_devs_release(struct device *dev)
168 struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
170 /* release the master device reference */
171 put_device(&chip->dev);
175 * tpm_class_shutdown() - prepare the TPM device for loss of power.
176 * @dev: device to which the chip is associated.
178 * Issues a TPM2_Shutdown command prior to loss of power, as required by the
180 * Then, calls bus- and device- specific shutdown code.
182 * XXX: This codepath relies on the fact that sysfs is not enabled for
183 * TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2
184 * has sysfs support enabled before TPM sysfs's implicit locking is fixed.
186 static int tpm_class_shutdown(struct device *dev)
188 struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
190 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
191 down_write(&chip->ops_sem);
192 tpm2_shutdown(chip, TPM2_SU_CLEAR);
194 up_write(&chip->ops_sem);
201 * tpm_chip_alloc() - allocate a new struct tpm_chip instance
202 * @pdev: device to which the chip is associated
203 * At this point pdev mst be initialized, but does not have to
205 * @ops: struct tpm_class_ops instance
207 * Allocates a new struct tpm_chip instance and assigns a free
208 * device number for it. Must be paired with put_device(&chip->dev).
210 struct tpm_chip *tpm_chip_alloc(struct device *pdev,
211 const struct tpm_class_ops *ops)
213 struct tpm_chip *chip;
216 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
218 return ERR_PTR(-ENOMEM);
220 mutex_init(&chip->tpm_mutex);
221 init_rwsem(&chip->ops_sem);
225 mutex_lock(&idr_lock);
226 rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
227 mutex_unlock(&idr_lock);
229 dev_err(pdev, "No available tpm device numbers\n");
235 device_initialize(&chip->dev);
236 device_initialize(&chip->devs);
238 chip->dev.class = tpm_class;
239 chip->dev.class->shutdown_pre = tpm_class_shutdown;
240 chip->dev.release = tpm_dev_release;
241 chip->dev.parent = pdev;
242 chip->dev.groups = chip->groups;
244 chip->devs.parent = pdev;
245 chip->devs.class = tpmrm_class;
246 chip->devs.release = tpm_devs_release;
247 /* get extra reference on main device to hold on
248 * behalf of devs. This holds the chip structure
249 * while cdevs is in use. The corresponding put
250 * is in the tpm_devs_release (TPM2 only)
252 if (chip->flags & TPM_CHIP_FLAG_TPM2)
253 get_device(&chip->dev);
255 if (chip->dev_num == 0)
256 chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
258 chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
261 MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
263 rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
266 rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
271 chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
273 cdev_init(&chip->cdev, &tpm_fops);
274 cdev_init(&chip->cdevs, &tpmrm_fops);
275 chip->cdev.owner = THIS_MODULE;
276 chip->cdevs.owner = THIS_MODULE;
278 chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
279 if (!chip->work_space.context_buf) {
283 chip->work_space.session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
284 if (!chip->work_space.session_buf) {
293 put_device(&chip->devs);
294 put_device(&chip->dev);
297 EXPORT_SYMBOL_GPL(tpm_chip_alloc);
300 * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
301 * @pdev: parent device to which the chip is associated
302 * @ops: struct tpm_class_ops instance
304 * Same as tpm_chip_alloc except devm is used to do the put_device
306 struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
307 const struct tpm_class_ops *ops)
309 struct tpm_chip *chip;
312 chip = tpm_chip_alloc(pdev, ops);
316 rc = devm_add_action_or_reset(pdev,
317 (void (*)(void *)) put_device,
322 dev_set_drvdata(pdev, chip);
326 EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
328 static int tpm_add_char_device(struct tpm_chip *chip)
332 rc = cdev_device_add(&chip->cdev, &chip->dev);
335 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
336 dev_name(&chip->dev), MAJOR(chip->dev.devt),
337 MINOR(chip->dev.devt), rc);
341 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
342 rc = cdev_device_add(&chip->cdevs, &chip->devs);
345 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
346 dev_name(&chip->devs), MAJOR(chip->devs.devt),
347 MINOR(chip->devs.devt), rc);
352 /* Make the chip available. */
353 mutex_lock(&idr_lock);
354 idr_replace(&dev_nums_idr, chip, chip->dev_num);
355 mutex_unlock(&idr_lock);
360 static void tpm_del_char_device(struct tpm_chip *chip)
362 cdev_device_del(&chip->cdev, &chip->dev);
364 /* Make the chip unavailable. */
365 mutex_lock(&idr_lock);
366 idr_replace(&dev_nums_idr, NULL, chip->dev_num);
367 mutex_unlock(&idr_lock);
369 /* Make the driver uncallable. */
370 down_write(&chip->ops_sem);
371 if (chip->flags & TPM_CHIP_FLAG_TPM2)
372 tpm2_shutdown(chip, TPM2_SU_CLEAR);
374 up_write(&chip->ops_sem);
377 static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
379 struct attribute **i;
381 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
384 sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
386 for (i = chip->groups[0]->attrs; *i != NULL; ++i)
387 sysfs_remove_link(&chip->dev.parent->kobj, (*i)->name);
390 /* For compatibility with legacy sysfs paths we provide symlinks from the
391 * parent dev directory to selected names within the tpm chip directory. Old
392 * kernel versions created these files directly under the parent.
394 static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
396 struct attribute **i;
399 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
402 rc = __compat_only_sysfs_link_entry_to_kobj(
403 &chip->dev.parent->kobj, &chip->dev.kobj, "ppi");
404 if (rc && rc != -ENOENT)
407 /* All the names from tpm-sysfs */
408 for (i = chip->groups[0]->attrs; *i != NULL; ++i) {
409 rc = __compat_only_sysfs_link_entry_to_kobj(
410 &chip->dev.parent->kobj, &chip->dev.kobj, (*i)->name);
412 tpm_del_legacy_sysfs(chip);
420 static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
422 struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng);
424 return tpm_get_random(chip, data, max);
427 static int tpm_add_hwrng(struct tpm_chip *chip)
429 if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
432 snprintf(chip->hwrng_name, sizeof(chip->hwrng_name),
433 "tpm-rng-%d", chip->dev_num);
434 chip->hwrng.name = chip->hwrng_name;
435 chip->hwrng.read = tpm_hwrng_read;
436 return hwrng_register(&chip->hwrng);
440 * tpm_chip_register() - create a character device for the TPM chip
441 * @chip: TPM chip to use.
443 * Creates a character device for the TPM chip and adds sysfs attributes for
444 * the device. As the last step this function adds the chip to the list of TPM
445 * chips available for in-kernel use.
447 * This function should be only called after the chip initialization is
450 int tpm_chip_register(struct tpm_chip *chip)
454 if (chip->ops->flags & TPM_OPS_AUTO_STARTUP) {
455 if (chip->flags & TPM_CHIP_FLAG_TPM2)
456 rc = tpm2_auto_startup(chip);
458 rc = tpm1_auto_startup(chip);
463 tpm_sysfs_add_device(chip);
465 rc = tpm_bios_log_setup(chip);
466 if (rc != 0 && rc != -ENODEV)
471 rc = tpm_add_hwrng(chip);
475 rc = tpm_add_char_device(chip);
479 rc = tpm_add_legacy_sysfs(chip);
481 tpm_chip_unregister(chip);
488 if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
489 hwrng_unregister(&chip->hwrng);
491 tpm_bios_log_teardown(chip);
495 EXPORT_SYMBOL_GPL(tpm_chip_register);
498 * tpm_chip_unregister() - release the TPM driver
499 * @chip: TPM chip to use.
501 * Takes the chip first away from the list of available TPM chips and then
502 * cleans up all the resources reserved by tpm_chip_register().
504 * Once this function returns the driver call backs in 'op's will not be
505 * running and will no longer start.
507 * NOTE: This function should be only called before deinitializing chip
510 void tpm_chip_unregister(struct tpm_chip *chip)
512 tpm_del_legacy_sysfs(chip);
513 if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
514 hwrng_unregister(&chip->hwrng);
515 tpm_bios_log_teardown(chip);
516 if (chip->flags & TPM_CHIP_FLAG_TPM2)
517 cdev_device_del(&chip->cdevs, &chip->devs);
518 tpm_del_char_device(chip);
520 EXPORT_SYMBOL_GPL(tpm_chip_unregister);