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 down_write(&chip->ops_sem);
191 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
192 tpm2_shutdown(chip, TPM2_SU_CLEAR);
196 up_write(&chip->ops_sem);
202 * tpm_chip_alloc() - allocate a new struct tpm_chip instance
203 * @pdev: device to which the chip is associated
204 * At this point pdev mst be initialized, but does not have to
206 * @ops: struct tpm_class_ops instance
208 * Allocates a new struct tpm_chip instance and assigns a free
209 * device number for it. Must be paired with put_device(&chip->dev).
211 struct tpm_chip *tpm_chip_alloc(struct device *pdev,
212 const struct tpm_class_ops *ops)
214 struct tpm_chip *chip;
217 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
219 return ERR_PTR(-ENOMEM);
221 mutex_init(&chip->tpm_mutex);
222 init_rwsem(&chip->ops_sem);
226 mutex_lock(&idr_lock);
227 rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
228 mutex_unlock(&idr_lock);
230 dev_err(pdev, "No available tpm device numbers\n");
236 device_initialize(&chip->dev);
237 device_initialize(&chip->devs);
239 chip->dev.class = tpm_class;
240 chip->dev.class->shutdown_pre = tpm_class_shutdown;
241 chip->dev.release = tpm_dev_release;
242 chip->dev.parent = pdev;
243 chip->dev.groups = chip->groups;
245 chip->devs.parent = pdev;
246 chip->devs.class = tpmrm_class;
247 chip->devs.release = tpm_devs_release;
248 /* get extra reference on main device to hold on
249 * behalf of devs. This holds the chip structure
250 * while cdevs is in use. The corresponding put
251 * is in the tpm_devs_release (TPM2 only)
253 if (chip->flags & TPM_CHIP_FLAG_TPM2)
254 get_device(&chip->dev);
256 if (chip->dev_num == 0)
257 chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
259 chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
262 MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
264 rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
267 rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
272 chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
274 cdev_init(&chip->cdev, &tpm_fops);
275 cdev_init(&chip->cdevs, &tpmrm_fops);
276 chip->cdev.owner = THIS_MODULE;
277 chip->cdevs.owner = THIS_MODULE;
279 rc = tpm2_init_space(&chip->work_space, TPM2_SPACE_BUFFER_SIZE);
289 put_device(&chip->devs);
290 put_device(&chip->dev);
293 EXPORT_SYMBOL_GPL(tpm_chip_alloc);
296 * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
297 * @pdev: parent device to which the chip is associated
298 * @ops: struct tpm_class_ops instance
300 * Same as tpm_chip_alloc except devm is used to do the put_device
302 struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
303 const struct tpm_class_ops *ops)
305 struct tpm_chip *chip;
308 chip = tpm_chip_alloc(pdev, ops);
312 rc = devm_add_action_or_reset(pdev,
313 (void (*)(void *)) put_device,
318 dev_set_drvdata(pdev, chip);
322 EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
324 static int tpm_add_char_device(struct tpm_chip *chip)
328 rc = cdev_device_add(&chip->cdev, &chip->dev);
331 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
332 dev_name(&chip->dev), MAJOR(chip->dev.devt),
333 MINOR(chip->dev.devt), rc);
337 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
338 rc = cdev_device_add(&chip->cdevs, &chip->devs);
341 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
342 dev_name(&chip->devs), MAJOR(chip->devs.devt),
343 MINOR(chip->devs.devt), rc);
348 /* Make the chip available. */
349 mutex_lock(&idr_lock);
350 idr_replace(&dev_nums_idr, chip, chip->dev_num);
351 mutex_unlock(&idr_lock);
356 static void tpm_del_char_device(struct tpm_chip *chip)
358 cdev_device_del(&chip->cdev, &chip->dev);
360 /* Make the chip unavailable. */
361 mutex_lock(&idr_lock);
362 idr_replace(&dev_nums_idr, NULL, chip->dev_num);
363 mutex_unlock(&idr_lock);
365 /* Make the driver uncallable. */
366 down_write(&chip->ops_sem);
367 if (chip->flags & TPM_CHIP_FLAG_TPM2)
368 tpm2_shutdown(chip, TPM2_SU_CLEAR);
370 up_write(&chip->ops_sem);
373 static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
375 struct attribute **i;
377 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
380 sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
382 for (i = chip->groups[0]->attrs; *i != NULL; ++i)
383 sysfs_remove_link(&chip->dev.parent->kobj, (*i)->name);
386 /* For compatibility with legacy sysfs paths we provide symlinks from the
387 * parent dev directory to selected names within the tpm chip directory. Old
388 * kernel versions created these files directly under the parent.
390 static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
392 struct attribute **i;
395 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
398 rc = __compat_only_sysfs_link_entry_to_kobj(
399 &chip->dev.parent->kobj, &chip->dev.kobj, "ppi");
400 if (rc && rc != -ENOENT)
403 /* All the names from tpm-sysfs */
404 for (i = chip->groups[0]->attrs; *i != NULL; ++i) {
405 rc = __compat_only_sysfs_link_entry_to_kobj(
406 &chip->dev.parent->kobj, &chip->dev.kobj, (*i)->name);
408 tpm_del_legacy_sysfs(chip);
416 static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
418 struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng);
420 return tpm_get_random(chip, data, max);
423 static int tpm_add_hwrng(struct tpm_chip *chip)
425 if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
428 snprintf(chip->hwrng_name, sizeof(chip->hwrng_name),
429 "tpm-rng-%d", chip->dev_num);
430 chip->hwrng.name = chip->hwrng_name;
431 chip->hwrng.read = tpm_hwrng_read;
432 return hwrng_register(&chip->hwrng);
436 * tpm_chip_register() - create a character device for the TPM chip
437 * @chip: TPM chip to use.
439 * Creates a character device for the TPM chip and adds sysfs attributes for
440 * the device. As the last step this function adds the chip to the list of TPM
441 * chips available for in-kernel use.
443 * This function should be only called after the chip initialization is
446 int tpm_chip_register(struct tpm_chip *chip)
450 if (chip->ops->flags & TPM_OPS_AUTO_STARTUP) {
451 if (chip->flags & TPM_CHIP_FLAG_TPM2)
452 rc = tpm2_auto_startup(chip);
454 rc = tpm1_auto_startup(chip);
459 tpm_sysfs_add_device(chip);
461 tpm_bios_log_setup(chip);
465 rc = tpm_add_hwrng(chip);
469 rc = tpm_add_char_device(chip);
473 rc = tpm_add_legacy_sysfs(chip);
475 tpm_chip_unregister(chip);
482 if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
483 hwrng_unregister(&chip->hwrng);
485 tpm_bios_log_teardown(chip);
489 EXPORT_SYMBOL_GPL(tpm_chip_register);
492 * tpm_chip_unregister() - release the TPM driver
493 * @chip: TPM chip to use.
495 * Takes the chip first away from the list of available TPM chips and then
496 * cleans up all the resources reserved by tpm_chip_register().
498 * Once this function returns the driver call backs in 'op's will not be
499 * running and will no longer start.
501 * NOTE: This function should be only called before deinitializing chip
504 void tpm_chip_unregister(struct tpm_chip *chip)
506 tpm_del_legacy_sysfs(chip);
507 if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
508 hwrng_unregister(&chip->hwrng);
509 tpm_bios_log_teardown(chip);
510 if (chip->flags & TPM_CHIP_FLAG_TPM2)
511 cdev_device_del(&chip->cdevs, &chip->devs);
512 tpm_del_char_device(chip);
514 EXPORT_SYMBOL_GPL(tpm_chip_unregister);