xref: /openbmc/linux/drivers/char/tpm/tpm2-cmd.c (revision 842ed298)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2014, 2015 Intel Corporation
4  *
5  * Authors:
6  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
7  *
8  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
9  *
10  * This file contains TPM2 protocol implementations of the commands
11  * used by the kernel internally.
12  */
13 
14 #include "tpm.h"
15 #include <crypto/hash_info.h>
16 
17 static struct tpm2_hash tpm2_hash_map[] = {
18 	{HASH_ALGO_SHA1, TPM_ALG_SHA1},
19 	{HASH_ALGO_SHA256, TPM_ALG_SHA256},
20 	{HASH_ALGO_SHA384, TPM_ALG_SHA384},
21 	{HASH_ALGO_SHA512, TPM_ALG_SHA512},
22 	{HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
23 };
24 
25 int tpm2_get_timeouts(struct tpm_chip *chip)
26 {
27 	/* Fixed timeouts for TPM2 */
28 	chip->timeout_a = msecs_to_jiffies(TPM2_TIMEOUT_A);
29 	chip->timeout_b = msecs_to_jiffies(TPM2_TIMEOUT_B);
30 	chip->timeout_c = msecs_to_jiffies(TPM2_TIMEOUT_C);
31 	chip->timeout_d = msecs_to_jiffies(TPM2_TIMEOUT_D);
32 
33 	/* PTP spec timeouts */
34 	chip->duration[TPM_SHORT] = msecs_to_jiffies(TPM2_DURATION_SHORT);
35 	chip->duration[TPM_MEDIUM] = msecs_to_jiffies(TPM2_DURATION_MEDIUM);
36 	chip->duration[TPM_LONG] = msecs_to_jiffies(TPM2_DURATION_LONG);
37 
38 	/* Key creation commands long timeouts */
39 	chip->duration[TPM_LONG_LONG] =
40 		msecs_to_jiffies(TPM2_DURATION_LONG_LONG);
41 
42 	chip->flags |= TPM_CHIP_FLAG_HAVE_TIMEOUTS;
43 
44 	return 0;
45 }
46 
47 /**
48  * tpm2_ordinal_duration_index() - returns an index to the chip duration table
49  * @ordinal: TPM command ordinal.
50  *
51  * The function returns an index to the chip duration table
52  * (enum tpm_duration), that describes the maximum amount of
53  * time the chip could take to return the result for a  particular ordinal.
54  *
55  * The values of the MEDIUM, and LONG durations are taken
56  * from the PC Client Profile (PTP) specification (750, 2000 msec)
57  *
58  * LONG_LONG is for commands that generates keys which empirically takes
59  * a longer time on some systems.
60  *
61  * Return:
62  * * TPM_MEDIUM
63  * * TPM_LONG
64  * * TPM_LONG_LONG
65  * * TPM_UNDEFINED
66  */
67 static u8 tpm2_ordinal_duration_index(u32 ordinal)
68 {
69 	switch (ordinal) {
70 	/* Startup */
71 	case TPM2_CC_STARTUP:                 /* 144 */
72 		return TPM_MEDIUM;
73 
74 	case TPM2_CC_SELF_TEST:               /* 143 */
75 		return TPM_LONG;
76 
77 	case TPM2_CC_GET_RANDOM:              /* 17B */
78 		return TPM_LONG;
79 
80 	case TPM2_CC_SEQUENCE_UPDATE:         /* 15C */
81 		return TPM_MEDIUM;
82 	case TPM2_CC_SEQUENCE_COMPLETE:       /* 13E */
83 		return TPM_MEDIUM;
84 	case TPM2_CC_EVENT_SEQUENCE_COMPLETE: /* 185 */
85 		return TPM_MEDIUM;
86 	case TPM2_CC_HASH_SEQUENCE_START:     /* 186 */
87 		return TPM_MEDIUM;
88 
89 	case TPM2_CC_VERIFY_SIGNATURE:        /* 177 */
90 		return TPM_LONG;
91 
92 	case TPM2_CC_PCR_EXTEND:              /* 182 */
93 		return TPM_MEDIUM;
94 
95 	case TPM2_CC_HIERARCHY_CONTROL:       /* 121 */
96 		return TPM_LONG;
97 	case TPM2_CC_HIERARCHY_CHANGE_AUTH:   /* 129 */
98 		return TPM_LONG;
99 
100 	case TPM2_CC_GET_CAPABILITY:          /* 17A */
101 		return TPM_MEDIUM;
102 
103 	case TPM2_CC_NV_READ:                 /* 14E */
104 		return TPM_LONG;
105 
106 	case TPM2_CC_CREATE_PRIMARY:          /* 131 */
107 		return TPM_LONG_LONG;
108 	case TPM2_CC_CREATE:                  /* 153 */
109 		return TPM_LONG_LONG;
110 	case TPM2_CC_CREATE_LOADED:           /* 191 */
111 		return TPM_LONG_LONG;
112 
113 	default:
114 		return TPM_UNDEFINED;
115 	}
116 }
117 
118 /**
119  * tpm2_calc_ordinal_duration() - calculate the maximum command duration
120  * @chip:    TPM chip to use.
121  * @ordinal: TPM command ordinal.
122  *
123  * The function returns the maximum amount of time the chip could take
124  * to return the result for a particular ordinal in jiffies.
125  *
126  * Return: A maximal duration time for an ordinal in jiffies.
127  */
128 unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
129 {
130 	unsigned int index;
131 
132 	index = tpm2_ordinal_duration_index(ordinal);
133 
134 	if (index != TPM_UNDEFINED)
135 		return chip->duration[index];
136 	else
137 		return msecs_to_jiffies(TPM2_DURATION_DEFAULT);
138 }
139 
140 
141 struct tpm2_pcr_read_out {
142 	__be32	update_cnt;
143 	__be32	pcr_selects_cnt;
144 	__be16	hash_alg;
145 	u8	pcr_select_size;
146 	u8	pcr_select[TPM2_PCR_SELECT_MIN];
147 	__be32	digests_cnt;
148 	__be16	digest_size;
149 	u8	digest[];
150 } __packed;
151 
152 /**
153  * tpm2_pcr_read() - read a PCR value
154  * @chip:	TPM chip to use.
155  * @pcr_idx:	index of the PCR to read.
156  * @digest:	PCR bank and buffer current PCR value is written to.
157  * @digest_size_ptr:	pointer to variable that stores the digest size.
158  *
159  * Return: Same as with tpm_transmit_cmd.
160  */
161 int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
162 		  struct tpm_digest *digest, u16 *digest_size_ptr)
163 {
164 	int i;
165 	int rc;
166 	struct tpm_buf buf;
167 	struct tpm2_pcr_read_out *out;
168 	u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
169 	u16 digest_size;
170 	u16 expected_digest_size = 0;
171 
172 	if (pcr_idx >= TPM2_PLATFORM_PCR)
173 		return -EINVAL;
174 
175 	if (!digest_size_ptr) {
176 		for (i = 0; i < chip->nr_allocated_banks &&
177 		     chip->allocated_banks[i].alg_id != digest->alg_id; i++)
178 			;
179 
180 		if (i == chip->nr_allocated_banks)
181 			return -EINVAL;
182 
183 		expected_digest_size = chip->allocated_banks[i].digest_size;
184 	}
185 
186 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
187 	if (rc)
188 		return rc;
189 
190 	pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
191 
192 	tpm_buf_append_u32(&buf, 1);
193 	tpm_buf_append_u16(&buf, digest->alg_id);
194 	tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN);
195 	tpm_buf_append(&buf, (const unsigned char *)pcr_select,
196 		       sizeof(pcr_select));
197 
198 	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to read a pcr value");
199 	if (rc)
200 		goto out;
201 
202 	out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
203 	digest_size = be16_to_cpu(out->digest_size);
204 	if (digest_size > sizeof(digest->digest) ||
205 	    (!digest_size_ptr && digest_size != expected_digest_size)) {
206 		rc = -EINVAL;
207 		goto out;
208 	}
209 
210 	if (digest_size_ptr)
211 		*digest_size_ptr = digest_size;
212 
213 	memcpy(digest->digest, out->digest, digest_size);
214 out:
215 	tpm_buf_destroy(&buf);
216 	return rc;
217 }
218 
219 struct tpm2_null_auth_area {
220 	__be32  handle;
221 	__be16  nonce_size;
222 	u8  attributes;
223 	__be16  auth_size;
224 } __packed;
225 
226 /**
227  * tpm2_pcr_extend() - extend a PCR value
228  *
229  * @chip:	TPM chip to use.
230  * @pcr_idx:	index of the PCR.
231  * @digests:	list of pcr banks and corresponding digest values to extend.
232  *
233  * Return: Same as with tpm_transmit_cmd.
234  */
235 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
236 		    struct tpm_digest *digests)
237 {
238 	struct tpm_buf buf;
239 	struct tpm2_null_auth_area auth_area;
240 	int rc;
241 	int i;
242 
243 	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
244 	if (rc)
245 		return rc;
246 
247 	tpm_buf_append_u32(&buf, pcr_idx);
248 
249 	auth_area.handle = cpu_to_be32(TPM2_RS_PW);
250 	auth_area.nonce_size = 0;
251 	auth_area.attributes = 0;
252 	auth_area.auth_size = 0;
253 
254 	tpm_buf_append_u32(&buf, sizeof(struct tpm2_null_auth_area));
255 	tpm_buf_append(&buf, (const unsigned char *)&auth_area,
256 		       sizeof(auth_area));
257 	tpm_buf_append_u32(&buf, chip->nr_allocated_banks);
258 
259 	for (i = 0; i < chip->nr_allocated_banks; i++) {
260 		tpm_buf_append_u16(&buf, digests[i].alg_id);
261 		tpm_buf_append(&buf, (const unsigned char *)&digests[i].digest,
262 			       chip->allocated_banks[i].digest_size);
263 	}
264 
265 	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting extend a PCR value");
266 
267 	tpm_buf_destroy(&buf);
268 
269 	return rc;
270 }
271 
272 struct tpm2_get_random_out {
273 	__be16 size;
274 	u8 buffer[TPM_MAX_RNG_DATA];
275 } __packed;
276 
277 /**
278  * tpm2_get_random() - get random bytes from the TPM RNG
279  *
280  * @chip:	a &tpm_chip instance
281  * @dest:	destination buffer
282  * @max:	the max number of random bytes to pull
283  *
284  * Return:
285  *   size of the buffer on success,
286  *   -errno otherwise (positive TPM return codes are masked to -EIO)
287  */
288 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
289 {
290 	struct tpm2_get_random_out *out;
291 	struct tpm_buf buf;
292 	u32 recd;
293 	u32 num_bytes = max;
294 	int err;
295 	int total = 0;
296 	int retries = 5;
297 	u8 *dest_ptr = dest;
298 
299 	if (!num_bytes || max > TPM_MAX_RNG_DATA)
300 		return -EINVAL;
301 
302 	err = tpm_buf_init(&buf, 0, 0);
303 	if (err)
304 		return err;
305 
306 	do {
307 		tpm_buf_reset(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_RANDOM);
308 		tpm_buf_append_u16(&buf, num_bytes);
309 		err = tpm_transmit_cmd(chip, &buf,
310 				       offsetof(struct tpm2_get_random_out,
311 						buffer),
312 				       "attempting get random");
313 		if (err) {
314 			if (err > 0)
315 				err = -EIO;
316 			goto out;
317 		}
318 
319 		out = (struct tpm2_get_random_out *)
320 			&buf.data[TPM_HEADER_SIZE];
321 		recd = min_t(u32, be16_to_cpu(out->size), num_bytes);
322 		if (tpm_buf_length(&buf) <
323 		    TPM_HEADER_SIZE +
324 		    offsetof(struct tpm2_get_random_out, buffer) +
325 		    recd) {
326 			err = -EFAULT;
327 			goto out;
328 		}
329 		memcpy(dest_ptr, out->buffer, recd);
330 
331 		dest_ptr += recd;
332 		total += recd;
333 		num_bytes -= recd;
334 	} while (retries-- && total < max);
335 
336 	tpm_buf_destroy(&buf);
337 	return total ? total : -EIO;
338 out:
339 	tpm_buf_destroy(&buf);
340 	return err;
341 }
342 
343 /**
344  * tpm2_flush_context() - execute a TPM2_FlushContext command
345  * @chip:	TPM chip to use
346  * @handle:	context handle
347  */
348 void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
349 {
350 	struct tpm_buf buf;
351 	int rc;
352 
353 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT);
354 	if (rc) {
355 		dev_warn(&chip->dev, "0x%08x was not flushed, out of memory\n",
356 			 handle);
357 		return;
358 	}
359 
360 	tpm_buf_append_u32(&buf, handle);
361 
362 	tpm_transmit_cmd(chip, &buf, 0, "flushing context");
363 	tpm_buf_destroy(&buf);
364 }
365 EXPORT_SYMBOL_GPL(tpm2_flush_context);
366 
367 struct tpm2_get_cap_out {
368 	u8 more_data;
369 	__be32 subcap_id;
370 	__be32 property_cnt;
371 	__be32 property_id;
372 	__be32 value;
373 } __packed;
374 
375 /**
376  * tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
377  * @chip:		a &tpm_chip instance
378  * @property_id:	property ID.
379  * @value:		output variable.
380  * @desc:		passed to tpm_transmit_cmd()
381  *
382  * Return:
383  *   0 on success,
384  *   -errno or a TPM return code otherwise
385  */
386 ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
387 			const char *desc)
388 {
389 	struct tpm2_get_cap_out *out;
390 	struct tpm_buf buf;
391 	int rc;
392 
393 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
394 	if (rc)
395 		return rc;
396 	tpm_buf_append_u32(&buf, TPM2_CAP_TPM_PROPERTIES);
397 	tpm_buf_append_u32(&buf, property_id);
398 	tpm_buf_append_u32(&buf, 1);
399 	rc = tpm_transmit_cmd(chip, &buf, 0, NULL);
400 	if (!rc) {
401 		out = (struct tpm2_get_cap_out *)
402 			&buf.data[TPM_HEADER_SIZE];
403 		*value = be32_to_cpu(out->value);
404 	}
405 	tpm_buf_destroy(&buf);
406 	return rc;
407 }
408 EXPORT_SYMBOL_GPL(tpm2_get_tpm_pt);
409 
410 /**
411  * tpm2_shutdown() - send a TPM shutdown command
412  *
413  * Sends a TPM shutdown command. The shutdown command is used in call
414  * sites where the system is going down. If it fails, there is not much
415  * that can be done except print an error message.
416  *
417  * @chip:		a &tpm_chip instance
418  * @shutdown_type:	TPM_SU_CLEAR or TPM_SU_STATE.
419  */
420 void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
421 {
422 	struct tpm_buf buf;
423 	int rc;
424 
425 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SHUTDOWN);
426 	if (rc)
427 		return;
428 	tpm_buf_append_u16(&buf, shutdown_type);
429 	tpm_transmit_cmd(chip, &buf, 0, "stopping the TPM");
430 	tpm_buf_destroy(&buf);
431 }
432 
433 /**
434  * tpm2_do_selftest() - ensure that all self tests have passed
435  *
436  * @chip: TPM chip to use
437  *
438  * Return: Same as with tpm_transmit_cmd.
439  *
440  * The TPM can either run all self tests synchronously and then return
441  * RC_SUCCESS once all tests were successful. Or it can choose to run the tests
442  * asynchronously and return RC_TESTING immediately while the self tests still
443  * execute in the background. This function handles both cases and waits until
444  * all tests have completed.
445  */
446 static int tpm2_do_selftest(struct tpm_chip *chip)
447 {
448 	struct tpm_buf buf;
449 	int full;
450 	int rc;
451 
452 	for (full = 0; full < 2; full++) {
453 		rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SELF_TEST);
454 		if (rc)
455 			return rc;
456 
457 		tpm_buf_append_u8(&buf, full);
458 		rc = tpm_transmit_cmd(chip, &buf, 0,
459 				      "attempting the self test");
460 		tpm_buf_destroy(&buf);
461 
462 		if (rc == TPM2_RC_TESTING)
463 			rc = TPM2_RC_SUCCESS;
464 		if (rc == TPM2_RC_INITIALIZE || rc == TPM2_RC_SUCCESS)
465 			return rc;
466 	}
467 
468 	return rc;
469 }
470 
471 /**
472  * tpm2_probe() - probe for the TPM 2.0 protocol
473  * @chip:	a &tpm_chip instance
474  *
475  * Send an idempotent TPM 2.0 command and see whether there is TPM2 chip in the
476  * other end based on the response tag. The flag TPM_CHIP_FLAG_TPM2 is set by
477  * this function if this is the case.
478  *
479  * Return:
480  *   0 on success,
481  *   -errno otherwise
482  */
483 int tpm2_probe(struct tpm_chip *chip)
484 {
485 	struct tpm_header *out;
486 	struct tpm_buf buf;
487 	int rc;
488 
489 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
490 	if (rc)
491 		return rc;
492 	tpm_buf_append_u32(&buf, TPM2_CAP_TPM_PROPERTIES);
493 	tpm_buf_append_u32(&buf, TPM_PT_TOTAL_COMMANDS);
494 	tpm_buf_append_u32(&buf, 1);
495 	rc = tpm_transmit_cmd(chip, &buf, 0, NULL);
496 	/* We ignore TPM return codes on purpose. */
497 	if (rc >=  0) {
498 		out = (struct tpm_header *)buf.data;
499 		if (be16_to_cpu(out->tag) == TPM2_ST_NO_SESSIONS)
500 			chip->flags |= TPM_CHIP_FLAG_TPM2;
501 	}
502 	tpm_buf_destroy(&buf);
503 	return 0;
504 }
505 EXPORT_SYMBOL_GPL(tpm2_probe);
506 
507 static int tpm2_init_bank_info(struct tpm_chip *chip, u32 bank_index)
508 {
509 	struct tpm_bank_info *bank = chip->allocated_banks + bank_index;
510 	struct tpm_digest digest = { .alg_id = bank->alg_id };
511 	int i;
512 
513 	/*
514 	 * Avoid unnecessary PCR read operations to reduce overhead
515 	 * and obtain identifiers of the crypto subsystem.
516 	 */
517 	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
518 		enum hash_algo crypto_algo = tpm2_hash_map[i].crypto_id;
519 
520 		if (bank->alg_id != tpm2_hash_map[i].tpm_id)
521 			continue;
522 
523 		bank->digest_size = hash_digest_size[crypto_algo];
524 		bank->crypto_id = crypto_algo;
525 		return 0;
526 	}
527 
528 	bank->crypto_id = HASH_ALGO__LAST;
529 
530 	return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
531 }
532 
533 struct tpm2_pcr_selection {
534 	__be16  hash_alg;
535 	u8  size_of_select;
536 	u8  pcr_select[3];
537 } __packed;
538 
539 ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
540 {
541 	struct tpm2_pcr_selection pcr_selection;
542 	struct tpm_buf buf;
543 	void *marker;
544 	void *end;
545 	void *pcr_select_offset;
546 	u32 sizeof_pcr_selection;
547 	u32 nr_possible_banks;
548 	u32 nr_alloc_banks = 0;
549 	u16 hash_alg;
550 	u32 rsp_len;
551 	int rc;
552 	int i = 0;
553 
554 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
555 	if (rc)
556 		return rc;
557 
558 	tpm_buf_append_u32(&buf, TPM2_CAP_PCRS);
559 	tpm_buf_append_u32(&buf, 0);
560 	tpm_buf_append_u32(&buf, 1);
561 
562 	rc = tpm_transmit_cmd(chip, &buf, 9, "get tpm pcr allocation");
563 	if (rc)
564 		goto out;
565 
566 	nr_possible_banks = be32_to_cpup(
567 		(__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);
568 
569 	chip->allocated_banks = kcalloc(nr_possible_banks,
570 					sizeof(*chip->allocated_banks),
571 					GFP_KERNEL);
572 	if (!chip->allocated_banks) {
573 		rc = -ENOMEM;
574 		goto out;
575 	}
576 
577 	marker = &buf.data[TPM_HEADER_SIZE + 9];
578 
579 	rsp_len = be32_to_cpup((__be32 *)&buf.data[2]);
580 	end = &buf.data[rsp_len];
581 
582 	for (i = 0; i < nr_possible_banks; i++) {
583 		pcr_select_offset = marker +
584 			offsetof(struct tpm2_pcr_selection, size_of_select);
585 		if (pcr_select_offset >= end) {
586 			rc = -EFAULT;
587 			break;
588 		}
589 
590 		memcpy(&pcr_selection, marker, sizeof(pcr_selection));
591 		hash_alg = be16_to_cpu(pcr_selection.hash_alg);
592 
593 		pcr_select_offset = memchr_inv(pcr_selection.pcr_select, 0,
594 					       pcr_selection.size_of_select);
595 		if (pcr_select_offset) {
596 			chip->allocated_banks[nr_alloc_banks].alg_id = hash_alg;
597 
598 			rc = tpm2_init_bank_info(chip, nr_alloc_banks);
599 			if (rc < 0)
600 				break;
601 
602 			nr_alloc_banks++;
603 		}
604 
605 		sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +
606 			sizeof(pcr_selection.size_of_select) +
607 			pcr_selection.size_of_select;
608 		marker = marker + sizeof_pcr_selection;
609 	}
610 
611 	chip->nr_allocated_banks = nr_alloc_banks;
612 out:
613 	tpm_buf_destroy(&buf);
614 
615 	return rc;
616 }
617 
618 int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
619 {
620 	struct tpm_buf buf;
621 	u32 nr_commands;
622 	__be32 *attrs;
623 	u32 cc;
624 	int i;
625 	int rc;
626 
627 	rc = tpm2_get_tpm_pt(chip, TPM_PT_TOTAL_COMMANDS, &nr_commands, NULL);
628 	if (rc)
629 		goto out;
630 
631 	if (nr_commands > 0xFFFFF) {
632 		rc = -EFAULT;
633 		goto out;
634 	}
635 
636 	chip->cc_attrs_tbl = devm_kcalloc(&chip->dev, 4, nr_commands,
637 					  GFP_KERNEL);
638 	if (!chip->cc_attrs_tbl) {
639 		rc = -ENOMEM;
640 		goto out;
641 	}
642 
643 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
644 	if (rc)
645 		goto out;
646 
647 	tpm_buf_append_u32(&buf, TPM2_CAP_COMMANDS);
648 	tpm_buf_append_u32(&buf, TPM2_CC_FIRST);
649 	tpm_buf_append_u32(&buf, nr_commands);
650 
651 	rc = tpm_transmit_cmd(chip, &buf, 9 + 4 * nr_commands, NULL);
652 	if (rc) {
653 		tpm_buf_destroy(&buf);
654 		goto out;
655 	}
656 
657 	if (nr_commands !=
658 	    be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE + 5])) {
659 		tpm_buf_destroy(&buf);
660 		goto out;
661 	}
662 
663 	chip->nr_commands = nr_commands;
664 
665 	attrs = (__be32 *)&buf.data[TPM_HEADER_SIZE + 9];
666 	for (i = 0; i < nr_commands; i++, attrs++) {
667 		chip->cc_attrs_tbl[i] = be32_to_cpup(attrs);
668 		cc = chip->cc_attrs_tbl[i] & 0xFFFF;
669 
670 		if (cc == TPM2_CC_CONTEXT_SAVE || cc == TPM2_CC_FLUSH_CONTEXT) {
671 			chip->cc_attrs_tbl[i] &=
672 				~(GENMASK(2, 0) << TPM2_CC_ATTR_CHANDLES);
673 			chip->cc_attrs_tbl[i] |= 1 << TPM2_CC_ATTR_CHANDLES;
674 		}
675 	}
676 
677 	tpm_buf_destroy(&buf);
678 
679 out:
680 	if (rc > 0)
681 		rc = -ENODEV;
682 	return rc;
683 }
684 EXPORT_SYMBOL_GPL(tpm2_get_cc_attrs_tbl);
685 
686 /**
687  * tpm2_startup - turn on the TPM
688  * @chip: TPM chip to use
689  *
690  * Normally the firmware should start the TPM. This function is provided as a
691  * workaround if this does not happen. A legal case for this could be for
692  * example when a TPM emulator is used.
693  *
694  * Return: same as tpm_transmit_cmd()
695  */
696 
697 static int tpm2_startup(struct tpm_chip *chip)
698 {
699 	struct tpm_buf buf;
700 	int rc;
701 
702 	dev_info(&chip->dev, "starting up the TPM manually\n");
703 
704 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_STARTUP);
705 	if (rc < 0)
706 		return rc;
707 
708 	tpm_buf_append_u16(&buf, TPM2_SU_CLEAR);
709 	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to start the TPM");
710 	tpm_buf_destroy(&buf);
711 
712 	return rc;
713 }
714 
715 /**
716  * tpm2_auto_startup - Perform the standard automatic TPM initialization
717  *                     sequence
718  * @chip: TPM chip to use
719  *
720  * Returns 0 on success, < 0 in case of fatal error.
721  */
722 int tpm2_auto_startup(struct tpm_chip *chip)
723 {
724 	int rc;
725 
726 	rc = tpm2_get_timeouts(chip);
727 	if (rc)
728 		goto out;
729 
730 	rc = tpm2_do_selftest(chip);
731 	if (rc && rc != TPM2_RC_INITIALIZE)
732 		goto out;
733 
734 	if (rc == TPM2_RC_INITIALIZE) {
735 		rc = tpm2_startup(chip);
736 		if (rc)
737 			goto out;
738 
739 		rc = tpm2_do_selftest(chip);
740 		if (rc)
741 			goto out;
742 	}
743 
744 	rc = tpm2_get_cc_attrs_tbl(chip);
745 
746 out:
747 	if (rc > 0)
748 		rc = -ENODEV;
749 	return rc;
750 }
751 
752 int tpm2_find_cc(struct tpm_chip *chip, u32 cc)
753 {
754 	int i;
755 
756 	for (i = 0; i < chip->nr_commands; i++)
757 		if (cc == (chip->cc_attrs_tbl[i] & GENMASK(15, 0)))
758 			return i;
759 
760 	return -1;
761 }
762