summaryrefslogtreecommitdiffstats
path: root/drivers/char/tpm/tpm-chip.c
blob: 67ec9d3d04f529ba07fa1feb926bd1809a78a405 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
/*
 * Copyright (C) 2004 IBM Corporation
 * Copyright (C) 2014 Intel Corporation
 *
 * Authors:
 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Dave Safford <safford@watson.ibm.com>
 * Reiner Sailer <sailer@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * TPM chip management routines.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, version 2 of the
 * License.
 *
 */

#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/freezer.h>
#include <linux/major.h>
#include "tpm.h"
#include "tpm_eventlog.h"

DEFINE_IDR(dev_nums_idr);
static DEFINE_MUTEX(idr_lock);

struct class *tpm_class;
struct class *tpmrm_class;
dev_t tpm_devt;

/**
 * tpm_try_get_ops() - Get a ref to the tpm_chip
 * @chip: Chip to ref
 *
 * The caller must already have some kind of locking to ensure that chip is
 * valid. This function will lock the chip so that the ops member can be
 * accessed safely. The locking prevents tpm_chip_unregister from
 * completing, so it should not be held for long periods.
 *
 * Returns -ERRNO if the chip could not be got.
 */
int tpm_try_get_ops(struct tpm_chip *chip)
{
	int rc = -EIO;

	get_device(&chip->dev);

	down_read(&chip->ops_sem);
	if (!chip->ops)
		goto out_lock;

	return 0;
out_lock:
	up_read(&chip->ops_sem);
	put_device(&chip->dev);
	return rc;
}
EXPORT_SYMBOL_GPL(tpm_try_get_ops);

/**
 * tpm_put_ops() - Release a ref to the tpm_chip
 * @chip: Chip to put
 *
 * This is the opposite pair to tpm_try_get_ops(). After this returns chip may
 * be kfree'd.
 */
void tpm_put_ops(struct tpm_chip *chip)
{
	up_read(&chip->ops_sem);
	put_device(&chip->dev);
}
EXPORT_SYMBOL_GPL(tpm_put_ops);

/**
 * tpm_chip_find_get() - return tpm_chip for a given chip number
 * @chip_num: id to find
 *
 * The return'd chip has been tpm_try_get_ops'd and must be released via
 * tpm_put_ops
 */
struct tpm_chip *tpm_chip_find_get(int chip_num)
{
	struct tpm_chip *chip, *res = NULL;
	int chip_prev;

	mutex_lock(&idr_lock);

	if (chip_num == TPM_ANY_NUM) {
		chip_num = 0;
		do {
			chip_prev = chip_num;
			chip = idr_get_next(&dev_nums_idr, &chip_num);
			if (chip && !tpm_try_get_ops(chip)) {
				res = chip;
				break;
			}
		} while (chip_prev != chip_num);
	} else {
		chip = idr_find(&dev_nums_idr, chip_num);
		if (chip && !tpm_try_get_ops(chip))
			res = chip;
	}

	mutex_unlock(&idr_lock);

	return res;
}

/**
 * tpm_dev_release() - free chip memory and the device number
 * @dev: the character device for the TPM chip
 *
 * This is used as the release function for the character device.
 */
static void tpm_dev_release(struct device *dev)
{
	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);

	mutex_lock(&idr_lock);
	idr_remove(&dev_nums_idr, chip->dev_num);
	mutex_unlock(&idr_lock);

	kfree(chip->log.bios_event_log);
	kfree(chip->work_space.context_buf);
	kfree(chip->work_space.session_buf);
	kfree(chip);
}

static void tpm_devs_release(struct device *dev)
{
	struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);

	/* release the master device reference */
	put_device(&chip->dev);
}

/**
 * tpm_class_shutdown() - prepare the TPM device for loss of power.
 * @dev: device to which the chip is associated.
 *
 * Issues a TPM2_Shutdown command prior to loss of power, as required by the
 * TPM 2.0 spec.
 * Then, calls bus- and device- specific shutdown code.
 *
 * XXX: This codepath relies on the fact that sysfs is not enabled for
 * TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2
 * has sysfs support enabled before TPM sysfs's implicit locking is fixed.
 */
static int tpm_class_shutdown(struct device *dev)
{
	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);

	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
		down_write(&chip->ops_sem);
		tpm2_shutdown(chip, TPM2_SU_CLEAR);
		chip->ops = NULL;
		up_write(&chip->ops_sem);
	}
	/* Allow bus- and device-specific code to run. Note: since chip->ops
	 * is NULL, more-specific shutdown code will not be able to issue TPM
	 * commands.
	 */
	if (dev->bus && dev->bus->shutdown)
		dev->bus->shutdown(dev);
	else if (dev->driver && dev->driver->shutdown)
		dev->driver->shutdown(dev);
	return 0;
}

/**
 * tpm_chip_alloc() - allocate a new struct tpm_chip instance
 * @pdev: device to which the chip is associated
 *        At this point pdev mst be initialized, but does not have to
 *        be registered
 * @ops: struct tpm_class_ops instance
 *
 * Allocates a new struct tpm_chip instance and assigns a free
 * device number for it. Must be paired with put_device(&chip->dev).
 */
struct tpm_chip *tpm_chip_alloc(struct device *pdev,
				const struct tpm_class_ops *ops)
{
	struct tpm_chip *chip;
	int rc;

	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
	if (chip == NULL)
		return ERR_PTR(-ENOMEM);

	mutex_init(&chip->tpm_mutex);
	init_rwsem(&chip->ops_sem);

	chip->ops = ops;

	mutex_lock(&idr_lock);
	rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
	mutex_unlock(&idr_lock);
	if (rc < 0) {
		dev_err(pdev, "No available tpm device numbers\n");
		kfree(chip);
		return ERR_PTR(rc);
	}
	chip->dev_num = rc;

	device_initialize(&chip->dev);
	device_initialize(&chip->devs);

	chip->dev.class = tpm_class;
	chip->dev.class->shutdown = tpm_class_shutdown;
	chip->dev.release = tpm_dev_release;
	chip->dev.parent = pdev;
	chip->dev.groups = chip->groups;

	chip->devs.parent = pdev;
	chip->devs.class = tpmrm_class;
	chip->devs.release = tpm_devs_release;
	/* get extra reference on main device to hold on
	 * behalf of devs.  This holds the chip structure
	 * while cdevs is in use.  The corresponding put
	 * is in the tpm_devs_release (TPM2 only)
	 */
	if (chip->flags & TPM_CHIP_FLAG_TPM2)
		get_device(&chip->dev);

	if (chip->dev_num == 0)
		chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
	else
		chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);

	chip->devs.devt =
		MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);

	rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
	if (rc)
		goto out;
	rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
	if (rc)
		goto out;

	if (!pdev)
		chip->flags |= TPM_CHIP_FLAG_VIRTUAL;

	cdev_init(&chip->cdev, &tpm_fops);
	cdev_init(&chip->cdevs, &tpmrm_fops);
	chip->cdev.owner = THIS_MODULE;
	chip->cdevs.owner = THIS_MODULE;

	chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (!chip->work_space.context_buf) {
		rc = -ENOMEM;
		goto out;
	}
	chip->work_space.session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (!chip->work_space.session_buf) {
		rc = -ENOMEM;
		goto out;
	}

	chip->locality = -1;
	return chip;

out:
	put_device(&chip->devs);
	put_device(&chip->dev);
	return ERR_PTR(rc);
}
EXPORT_SYMBOL_GPL(tpm_chip_alloc);

/**
 * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
 * @pdev: parent device to which the chip is associated
 * @ops: struct tpm_class_ops instance
 *
 * Same as tpm_chip_alloc except devm is used to do the put_device
 */
struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
				 const struct tpm_class_ops *ops)
{
	struct tpm_chip *chip;
	int rc;

	chip = tpm_chip_alloc(pdev, ops);
	if (IS_ERR(chip))
		return chip;

	rc = devm_add_action_or_reset(pdev,
				      (void (*)(void *)) put_device,
				      &chip->dev);
	if (rc)
		return ERR_PTR(rc);

	dev_set_drvdata(pdev, chip);

	return chip;
}
EXPORT_SYMBOL_GPL(tpmm_chip_alloc);

static int tpm_add_char_device(struct tpm_chip *chip)
{
	int rc;

	rc = cdev_device_add(&chip->cdev, &chip->dev);
	if (rc) {
		dev_err(&chip->dev,
			"unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
			dev_name(&chip->dev), MAJOR(chip->dev.devt),
			MINOR(chip->dev.devt), rc);
		return rc;
	}

	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
		rc = cdev_device_add(&chip->cdevs, &chip->devs);
		if (rc) {
			dev_err(&chip->devs,
				"unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
				dev_name(&chip->devs), MAJOR(chip->devs.devt),
				MINOR(chip->devs.devt), rc);
			return rc;
		}
	}

	/* Make the chip available. */
	mutex_lock(&idr_lock);
	idr_replace(&dev_nums_idr, chip, chip->dev_num);
	mutex_unlock(&idr_lock);

	return rc;
}

static void tpm_del_char_device(struct tpm_chip *chip)
{
	cdev_device_del(&chip->cdev, &chip->dev);

	/* Make the chip unavailable. */
	mutex_lock(&idr_lock);
	idr_replace(&dev_nums_idr, NULL, chip->dev_num);
	mutex_unlock(&idr_lock);

	/* Make the driver uncallable. */
	down_write(&chip->ops_sem);
	if (chip->flags & TPM_CHIP_FLAG_TPM2)
		tpm2_shutdown(chip, TPM2_SU_CLEAR);
	chip->ops = NULL;
	up_write(&chip->ops_sem);
}

static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
{
	struct attribute **i;

	if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
		return;

	sysfs_remove_link(&chip->dev.parent->kobj, "ppi");

	for (i = chip->groups[0]->attrs; *i != NULL; ++i)
		sysfs_remove_link(&chip->dev.parent->kobj, (*i)->name);
}

/* For compatibility with legacy sysfs paths we provide symlinks from the
 * parent dev directory to selected names within the tpm chip directory. Old
 * kernel versions created these files directly under the parent.
 */
static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
{
	struct attribute **i;
	int rc;

	if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
		return 0;

	rc = __compat_only_sysfs_link_entry_to_kobj(
		    &chip->dev.parent->kobj, &chip->dev.kobj, "ppi");
	if (rc && rc != -ENOENT)
		return rc;

	/* All the names from tpm-sysfs */
	for (i = chip->groups[0]->attrs; *i != NULL; ++i) {
		rc = __compat_only_sysfs_link_entry_to_kobj(
		    &chip->dev.parent->kobj, &chip->dev.kobj, (*i)->name);
		if (rc) {
			tpm_del_legacy_sysfs(chip);
			return rc;
		}
	}

	return 0;
}
/*
 * tpm_chip_register() - create a character device for the TPM chip
 * @chip: TPM chip to use.
 *
 * Creates a character device for the TPM chip and adds sysfs attributes for
 * the device. As the last step this function adds the chip to the list of TPM
 * chips available for in-kernel use.
 *
 * This function should be only called after the chip initialization is
 * complete.
 */
int tpm_chip_register(struct tpm_chip *chip)
{
	int rc;

	if (chip->ops->flags & TPM_OPS_AUTO_STARTUP) {
		if (chip->flags & TPM_CHIP_FLAG_TPM2)
			rc = tpm2_auto_startup(chip);
		else
			rc = tpm1_auto_startup(chip);
		if (rc)
			return rc;
	}

	tpm_sysfs_add_device(chip);

	rc = tpm_bios_log_setup(chip);
	if (rc != 0 && rc != -ENODEV)
		return rc;

	tpm_add_ppi(chip);

	rc = tpm_add_char_device(chip);
	if (rc) {
		tpm_bios_log_teardown(chip);
		return rc;
	}

	rc = tpm_add_legacy_sysfs(chip);
	if (rc) {
		tpm_chip_unregister(chip);
		return rc;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(tpm_chip_register);

/*
 * tpm_chip_unregister() - release the TPM driver
 * @chip: TPM chip to use.
 *
 * Takes the chip first away from the list of available TPM chips and then
 * cleans up all the resources reserved by tpm_chip_register().
 *
 * Once this function returns the driver call backs in 'op's will not be
 * running and will no longer start.
 *
 * NOTE: This function should be only called before deinitializing chip
 * resources.
 */
void tpm_chip_unregister(struct tpm_chip *chip)
{
	tpm_del_legacy_sysfs(chip);
	tpm_bios_log_teardown(chip);
	if (chip->flags & TPM_CHIP_FLAG_TPM2)
		cdev_device_del(&chip->cdevs, &chip->devs);
	tpm_del_char_device(chip);
}
EXPORT_SYMBOL_GPL(tpm_chip_unregister);