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);
167 * tpm_class_shutdown() - prepare the TPM device for loss of power.
168 * @dev: device to which the chip is associated.
170 * Issues a TPM2_Shutdown command prior to loss of power, as required by the
172 * Then, calls bus- and device- specific shutdown code.
174 * XXX: This codepath relies on the fact that sysfs is not enabled for
175 * TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2
176 * has sysfs support enabled before TPM sysfs's implicit locking is fixed.
178 static int tpm_class_shutdown(struct device *dev)
180 struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
182 down_write(&chip->ops_sem);
183 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
184 tpm2_shutdown(chip, TPM2_SU_CLEAR);
188 up_write(&chip->ops_sem);
194 * tpm_chip_alloc() - allocate a new struct tpm_chip instance
195 * @pdev: device to which the chip is associated
196 * At this point pdev mst be initialized, but does not have to
198 * @ops: struct tpm_class_ops instance
200 * Allocates a new struct tpm_chip instance and assigns a free
201 * device number for it. Must be paired with put_device(&chip->dev).
203 struct tpm_chip *tpm_chip_alloc(struct device *pdev,
204 const struct tpm_class_ops *ops)
206 struct tpm_chip *chip;
209 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
211 return ERR_PTR(-ENOMEM);
213 mutex_init(&chip->tpm_mutex);
214 init_rwsem(&chip->ops_sem);
218 mutex_lock(&idr_lock);
219 rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
220 mutex_unlock(&idr_lock);
222 dev_err(pdev, "No available tpm device numbers\n");
228 device_initialize(&chip->dev);
230 chip->dev.class = tpm_class;
231 chip->dev.class->shutdown_pre = tpm_class_shutdown;
232 chip->dev.release = tpm_dev_release;
233 chip->dev.parent = pdev;
234 chip->dev.groups = chip->groups;
236 if (chip->dev_num == 0)
237 chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
239 chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
241 rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
246 chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
248 cdev_init(&chip->cdev, &tpm_fops);
249 chip->cdev.owner = THIS_MODULE;
251 rc = tpm2_init_space(&chip->work_space, TPM2_SPACE_BUFFER_SIZE);
261 put_device(&chip->dev);
264 EXPORT_SYMBOL_GPL(tpm_chip_alloc);
267 * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
268 * @pdev: parent device to which the chip is associated
269 * @ops: struct tpm_class_ops instance
271 * Same as tpm_chip_alloc except devm is used to do the put_device
273 struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
274 const struct tpm_class_ops *ops)
276 struct tpm_chip *chip;
279 chip = tpm_chip_alloc(pdev, ops);
283 rc = devm_add_action_or_reset(pdev,
284 (void (*)(void *)) put_device,
289 dev_set_drvdata(pdev, chip);
293 EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
295 static int tpm_add_char_device(struct tpm_chip *chip)
299 rc = cdev_device_add(&chip->cdev, &chip->dev);
302 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
303 dev_name(&chip->dev), MAJOR(chip->dev.devt),
304 MINOR(chip->dev.devt), rc);
308 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
309 rc = tpm_devs_add(chip);
314 /* Make the chip available. */
315 mutex_lock(&idr_lock);
316 idr_replace(&dev_nums_idr, chip, chip->dev_num);
317 mutex_unlock(&idr_lock);
322 cdev_device_del(&chip->cdev, &chip->dev);
326 static void tpm_del_char_device(struct tpm_chip *chip)
328 cdev_device_del(&chip->cdev, &chip->dev);
330 /* Make the chip unavailable. */
331 mutex_lock(&idr_lock);
332 idr_replace(&dev_nums_idr, NULL, chip->dev_num);
333 mutex_unlock(&idr_lock);
335 /* Make the driver uncallable. */
336 down_write(&chip->ops_sem);
337 if (chip->flags & TPM_CHIP_FLAG_TPM2)
338 tpm2_shutdown(chip, TPM2_SU_CLEAR);
340 up_write(&chip->ops_sem);
343 static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
345 struct attribute **i;
347 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
350 sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
352 for (i = chip->groups[0]->attrs; *i != NULL; ++i)
353 sysfs_remove_link(&chip->dev.parent->kobj, (*i)->name);
356 /* For compatibility with legacy sysfs paths we provide symlinks from the
357 * parent dev directory to selected names within the tpm chip directory. Old
358 * kernel versions created these files directly under the parent.
360 static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
362 struct attribute **i;
365 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
368 rc = __compat_only_sysfs_link_entry_to_kobj(
369 &chip->dev.parent->kobj, &chip->dev.kobj, "ppi");
370 if (rc && rc != -ENOENT)
373 /* All the names from tpm-sysfs */
374 for (i = chip->groups[0]->attrs; *i != NULL; ++i) {
375 rc = __compat_only_sysfs_link_entry_to_kobj(
376 &chip->dev.parent->kobj, &chip->dev.kobj, (*i)->name);
378 tpm_del_legacy_sysfs(chip);
386 static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
388 struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng);
390 return tpm_get_random(chip, data, max);
393 static int tpm_add_hwrng(struct tpm_chip *chip)
395 if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
398 snprintf(chip->hwrng_name, sizeof(chip->hwrng_name),
399 "tpm-rng-%d", chip->dev_num);
400 chip->hwrng.name = chip->hwrng_name;
401 chip->hwrng.read = tpm_hwrng_read;
402 return hwrng_register(&chip->hwrng);
406 * tpm_chip_register() - create a character device for the TPM chip
407 * @chip: TPM chip to use.
409 * Creates a character device for the TPM chip and adds sysfs attributes for
410 * the device. As the last step this function adds the chip to the list of TPM
411 * chips available for in-kernel use.
413 * This function should be only called after the chip initialization is
416 int tpm_chip_register(struct tpm_chip *chip)
420 if (chip->ops->flags & TPM_OPS_AUTO_STARTUP) {
421 if (chip->flags & TPM_CHIP_FLAG_TPM2)
422 rc = tpm2_auto_startup(chip);
424 rc = tpm1_auto_startup(chip);
429 tpm_sysfs_add_device(chip);
431 tpm_bios_log_setup(chip);
435 rc = tpm_add_hwrng(chip);
439 rc = tpm_add_char_device(chip);
443 rc = tpm_add_legacy_sysfs(chip);
445 tpm_chip_unregister(chip);
452 if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
453 hwrng_unregister(&chip->hwrng);
455 tpm_bios_log_teardown(chip);
459 EXPORT_SYMBOL_GPL(tpm_chip_register);
462 * tpm_chip_unregister() - release the TPM driver
463 * @chip: TPM chip to use.
465 * Takes the chip first away from the list of available TPM chips and then
466 * cleans up all the resources reserved by tpm_chip_register().
468 * Once this function returns the driver call backs in 'op's will not be
469 * running and will no longer start.
471 * NOTE: This function should be only called before deinitializing chip
474 void tpm_chip_unregister(struct tpm_chip *chip)
476 tpm_del_legacy_sysfs(chip);
477 if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
478 hwrng_unregister(&chip->hwrng);
479 tpm_bios_log_teardown(chip);
480 if (chip->flags & TPM_CHIP_FLAG_TPM2)
481 tpm_devs_remove(chip);
482 tpm_del_char_device(chip);
484 EXPORT_SYMBOL_GPL(tpm_chip_unregister);