summaryrefslogtreecommitdiff
path: root/src/soc/intel/common/mrc_cache.c
blob: e0d4b7de0130c6f5f973ef9628218afd21ddd22a (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
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2014 Google Inc.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <string.h>
#include <boot_device.h>
#include <bootstate.h>
#include <console/console.h>
#include <cbmem.h>
#include <elog.h>
#include <fmap.h>
#include <ip_checksum.h>
#include <region_file.h>
#include <vboot/vboot_common.h>

#include "mrc_cache.h"
#include "nvm.h"

#define DEFAULT_MRC_CACHE	"RW_MRC_CACHE"
#define VARIABLE_MRC_CACHE	"RW_VAR_MRC_CACHE"
#define RECOVERY_MRC_CACHE	"RECOVERY_MRC_CACHE"
#define UNIFIED_MRC_CACHE	"UNIFIED_MRC_CACHE"

#define MRC_DATA_SIGNATURE       (('M'<<0)|('R'<<8)|('C'<<16)|('D'<<24))

struct mrc_metadata {
	uint32_t signature;
	uint32_t data_size;
	uint16_t data_checksum;
	uint16_t header_checksum;
	uint32_t version;
} __attribute__((packed));

enum result {
	UPDATE_FAILURE		= -1,
	UPDATE_SUCCESS		= 0,
	ALREADY_UPTODATE	= 1
};

#define NORMAL_FLAG (1 << 0)
#define RECOVERY_FLAG (1 << 1)

struct cache_region {
	const char *name;
	uint32_t cbmem_id;
	int type;
	int elog_slot;
	int flags;
};

static const struct cache_region recovery_training = {
	.name = RECOVERY_MRC_CACHE,
	.cbmem_id = CBMEM_ID_MRCDATA,
	.type = MRC_TRAINING_DATA,
	.elog_slot = ELOG_MEM_CACHE_UPDATE_SLOT_RECOVERY,
#if IS_ENABLED(CONFIG_HAS_RECOVERY_MRC_CACHE)
	.flags = RECOVERY_FLAG,
#else
	.flags = 0,
#endif
};

static const struct cache_region normal_training = {
	.name = DEFAULT_MRC_CACHE,
	.cbmem_id = CBMEM_ID_MRCDATA,
	.type = MRC_TRAINING_DATA,
	.elog_slot = ELOG_MEM_CACHE_UPDATE_SLOT_NORMAL,
	.flags = NORMAL_FLAG | RECOVERY_FLAG,
};

static const struct cache_region variable_data = {
	.name = VARIABLE_MRC_CACHE,
	.cbmem_id = CBMEM_ID_VAR_MRCDATA,
	.type = MRC_VARIABLE_DATA,
	.elog_slot = ELOG_MEM_CACHE_UPDATE_SLOT_VARIABLE,
	.flags = NORMAL_FLAG | RECOVERY_FLAG,
};

/* Order matters here for priority in matching. */
static const struct cache_region *cache_regions[] = {
	&recovery_training,
	&normal_training,
	&variable_data,
};

static int lookup_region_by_name(const char *name, struct region *r)
{
	/* This assumes memory mapped boot media just under 4GiB. */
	const uint32_t pointer_base_32bit = -CONFIG_ROM_SIZE;

	if (fmap_locate_area(name, r) == 0)
		return 0;

	/* CHROMEOS builds must get their MRC cache from FMAP. */
	if (IS_ENABLED(CONFIG_CHROMEOS)) {
		printk(BIOS_ERR, "MRC: Chrome OS lookup failure.\n");
		return -1;
	}

	if (!IS_ENABLED(CONFIG_BOOT_DEVICE_MEMORY_MAPPED))
		return -1;

	/* Base is in the form of a pointer. Make it an offset. */
	r->offset = CONFIG_MRC_SETTINGS_CACHE_BASE - pointer_base_32bit;
	r->size = CONFIG_MRC_SETTINGS_CACHE_SIZE;

	return 0;
}

static const struct cache_region *lookup_region_type(int type)
{
	int i;
	int flags;

	if (vboot_recovery_mode_enabled())
		flags = RECOVERY_FLAG;
	else
		flags = NORMAL_FLAG;

	for (i = 0; i < ARRAY_SIZE(cache_regions); i++) {
		if (cache_regions[i]->type != type)
			continue;
		if ((cache_regions[i]->flags & flags) == flags)
			return cache_regions[i];
	}

	return NULL;
}

int mrc_cache_stash_data(int type, uint32_t version, const void *data,
			size_t size)
{
	const struct cache_region *cr;
	size_t cbmem_size;
	struct mrc_metadata *md;

	cr = lookup_region_type(type);
	if (cr == NULL) {
		printk(BIOS_ERR, "MRC: failed to add to cbmem for type %d.\n",
			type);
		return -1;
	}

	cbmem_size = sizeof(*md) + size;

	md = cbmem_add(cr->cbmem_id, cbmem_size);

	if (md == NULL) {
		printk(BIOS_ERR, "MRC: failed to add '%s' to cbmem.\n",
			cr->name);
		return -1;
	}

	memset(md, 0, sizeof(*md));
	md->signature = MRC_DATA_SIGNATURE;
	md->data_size = size;
	md->version = version;
	md->data_checksum = compute_ip_checksum(data, size);
	md->header_checksum = compute_ip_checksum(md, sizeof(*md));
	memcpy(&md[1], data, size);

	return 0;
}

static const struct cache_region *lookup_region(struct region *r, int type)
{
	const struct cache_region *cr;

	cr = lookup_region_type(type);

	if (cr == NULL) {
		printk(BIOS_ERR, "MRC: failed to locate region type %d.\n",
			type);
		return NULL;
	}

	if (lookup_region_by_name(cr->name, r) < 0)
		return NULL;

	return cr;
}

static int mrc_header_valid(struct region_device *rdev, struct mrc_metadata *md)
{
	uint16_t checksum;
	uint16_t checksum_result;
	size_t size;

	if (rdev_readat(rdev, md, 0, sizeof(*md)) < 0) {
		printk(BIOS_ERR, "MRC: couldn't read metadata\n");
		return -1;
	}

	if (md->signature != MRC_DATA_SIGNATURE) {
		printk(BIOS_ERR, "MRC: invalid header signature\n");
		return -1;
	}

	/* Compute checksum over header with 0 as the value. */
	checksum = md->header_checksum;
	md->header_checksum = 0;
	checksum_result = compute_ip_checksum(md, sizeof(*md));

	if (checksum != checksum_result) {
		printk(BIOS_ERR, "MRC: header checksum mismatch: %x vs %x\n",
			checksum, checksum_result);
		return -1;
	}

	/* Put back original. */
	md->header_checksum = checksum;

	/* Re-size the region device according to the metadata as a region_file
	 * does block allocation. */
	size = sizeof(*md) + md->data_size;
	if (rdev_chain(rdev, rdev, 0, size) < 0) {
		printk(BIOS_ERR, "MRC: size exceeds rdev size: %zx vs %zx\n",
			size, region_device_sz(rdev));
		return -1;
	}

	return 0;
}

static int mrc_data_valid(const struct region_device *rdev,
				const struct mrc_metadata *md)
{
	void *data;
	uint16_t checksum;
	const size_t md_size = sizeof(*md);
	const size_t data_size = md->data_size;

	data = rdev_mmap(rdev, md_size, data_size);
	if (data == NULL) {
		printk(BIOS_ERR, "MRC: mmap failure on data verification.\n");
		return -1;
	}

	checksum = compute_ip_checksum(data, data_size);

	rdev_munmap(rdev, data);
	if (md->data_checksum != checksum) {
		printk(BIOS_ERR, "MRC: data checksum mismatch: %x vs %x\n",
			md->data_checksum, checksum);
		return -1;
	}

	return 0;
}

static int mrc_cache_latest(const char *name,
				const struct region_device *backing_rdev,
				struct mrc_metadata *md,
				struct region_file *cache_file,
				struct region_device *rdev,
				bool fail_bad_data)
{
	/* Init and obtain a handle to the file data. */
	if (region_file_init(cache_file, backing_rdev) < 0) {
		printk(BIOS_ERR, "MRC: region file invalid in '%s'\n", name);
		return -1;
	}

	/* Provide a 0 sized region_device from here on out so the caller
	 * has a valid yet unusable region_device. */
	rdev_chain(rdev, backing_rdev, 0, 0);

	/* No data to return. */
	if (region_file_data(cache_file, rdev) < 0) {
		printk(BIOS_ERR, "MRC: no data in '%s'\n", name);
		return fail_bad_data ? -1 : 0;
	}

	/* Validate header and resize region to reflect actual usage on the
	 * saved medium (including metadata and data). */
	if (mrc_header_valid(rdev, md) < 0) {
		printk(BIOS_ERR, "MRC: invalid header in '%s'\n", name);
		return fail_bad_data ? -1 : 0;
	}

	/* Validate Data */
	if (mrc_data_valid(rdev, md) < 0) {
		printk(BIOS_ERR, "MRC: invalid data in '%s'\n", name);
		return fail_bad_data ? -1 : 0;
	}

	return 0;
}

int mrc_cache_get_current(int type, uint32_t version,
				struct region_device *rdev)
{
	const struct cache_region *cr;
	struct region region;
	struct region_device read_rdev;
	struct region_file cache_file;
	struct mrc_metadata md;
	size_t data_size;
	const size_t md_size = sizeof(md);
	const bool fail_bad_data = true;

	cr = lookup_region(&region, type);

	if (cr == NULL)
		return -1;

	if (boot_device_ro_subregion(&region, &read_rdev) < 0)
		return -1;

	if (mrc_cache_latest(cr->name, &read_rdev, &md, &cache_file, rdev,
		fail_bad_data) < 0)
		return -1;

	if (version != md.version) {
		printk(BIOS_INFO, "MRC: version mismatch: %x vs %x\n",
			md.version, version);
		return -1;
	}

	/* Re-size rdev to only contain the data. i.e. remove metadata. */
	data_size = md.data_size;
	return rdev_chain(rdev, rdev, md_size, data_size);
}

static bool mrc_cache_needs_update(const struct region_device *rdev,
				const struct cbmem_entry *to_be_updated)
{
	void *mapping;
	size_t size = region_device_sz(rdev);
	bool need_update = false;

	if (cbmem_entry_size(to_be_updated) != size)
		return true;

	mapping = rdev_mmap_full(rdev);

	if (memcmp(cbmem_entry_start(to_be_updated), mapping, size))
		need_update = true;

	rdev_munmap(rdev, mapping);

	return need_update;
}

static void log_event_cache_update(uint8_t slot, enum result res)
{
	const int type = ELOG_TYPE_MEM_CACHE_UPDATE;
	struct elog_event_mem_cache_update event = {
		.slot = slot
	};

	/* Filter through interesting events only */
	switch (res) {
	case UPDATE_FAILURE:
		event.status = ELOG_MEM_CACHE_UPDATE_STATUS_FAIL;
		break;
	case UPDATE_SUCCESS:
		event.status = ELOG_MEM_CACHE_UPDATE_STATUS_SUCCESS;
		break;
	default:
		return;
	}

	if (elog_add_event_raw(type, &event, sizeof(event)) < 0)
		printk(BIOS_ERR, "Failed to log mem cache update event.\n");
}

/* During ramstage this code purposefully uses incoherent transactions between
 * read and write. The read assumes a memory-mapped boot device that can be used
 * to quickly locate and compare the up-to-date data. However, when an update
 * is required it uses the writeable region access to perform the update. */
static void update_mrc_cache_by_type(int type)
{
	const struct cache_region *cr;
	struct region region;
	struct region_device read_rdev;
	struct region_device write_rdev;
	struct region_file cache_file;
	struct mrc_metadata md;
	const struct cbmem_entry *to_be_updated;
	struct incoherent_rdev backing_irdev;
	const struct region_device *backing_rdev;
	struct region_device latest_rdev;
	const bool fail_bad_data = false;

	cr = lookup_region(&region, type);

	if (cr == NULL)
		return;

	to_be_updated = cbmem_entry_find(cr->cbmem_id);
	if (to_be_updated == NULL) {
		printk(BIOS_ERR, "MRC: No data in cbmem for '%s'.\n",
			cr->name);
		return;
	}

	printk(BIOS_DEBUG, "MRC: Checking cached data update for '%s'.\n",
		cr->name);

	if (boot_device_ro_subregion(&region, &read_rdev) < 0)
		return;

	if (boot_device_rw_subregion(&region, &write_rdev) < 0)
		return;

	backing_rdev = incoherent_rdev_init(&backing_irdev, &region, &read_rdev,
						&write_rdev);

	if (backing_rdev == NULL)
		return;

	if (mrc_cache_latest(cr->name, backing_rdev, &md, &cache_file,
		&latest_rdev, fail_bad_data) < 0)
		return;

	if (!mrc_cache_needs_update(&latest_rdev, to_be_updated)) {
		log_event_cache_update(cr->elog_slot, ALREADY_UPTODATE);
		return;
	}

	printk(BIOS_DEBUG, "MRC: cache data '%s' needs update.\n", cr->name);

	if (region_file_update_data(&cache_file,
		cbmem_entry_start(to_be_updated),
		cbmem_entry_size(to_be_updated)) < 0)
		log_event_cache_update(cr->elog_slot, UPDATE_FAILURE);
	else
		log_event_cache_update(cr->elog_slot, UPDATE_SUCCESS);
}

/* Protect mrc region with a Protected Range Register */
static int protect_mrc_cache(const char *name)
{
	struct region region;

	if (!IS_ENABLED(CONFIG_MRC_SETTINGS_PROTECT))
		return 0;

	if (lookup_region_by_name(name, &region) < 0) {
		printk(BIOS_ERR, "MRC: Could not find region '%s'\n", name);
		return -1;
	}

	if (nvm_is_write_protected() <= 0) {
		printk(BIOS_INFO, "MRC: NOT enabling PRR for '%s'.\n", name);
		return 0;
	}

	if (nvm_protect(&region) < 0) {
		printk(BIOS_ERR, "MRC: ERROR setting PRR for '%s'.\n", name);
		return -1;
	}

	printk(BIOS_INFO, "MRC: Enabled Protected Range on '%s'.\n", name);
	return 0;
}

static void protect_mrc_region(void)
{
	/*
	 * Check if there is a single unified region that encompasses both
	 * RECOVERY_MRC_CACHE and DEFAULT_MRC_CACHE. In that case protect the
	 * entire region using a single PRR.
	 *
	 * If we are not able to protect the entire region, try protecting
	 * individual regions next.
	 */
	if (protect_mrc_cache(UNIFIED_MRC_CACHE) == 0)
		return;

	if (IS_ENABLED(CONFIG_HAS_RECOVERY_MRC_CACHE))
		protect_mrc_cache(RECOVERY_MRC_CACHE);

	protect_mrc_cache(DEFAULT_MRC_CACHE);
}

static void invalidate_normal_cache(void)
{
	struct region_file cache_file;
	struct region_device rdev;
	const char *name = DEFAULT_MRC_CACHE;
	const uint32_t invalid = ~MRC_DATA_SIGNATURE;

	/* Invalidate only on recovery mode with retraining enabled. */
	if (!vboot_recovery_mode_enabled())
		return;
	if (!vboot_recovery_mode_memory_retrain())
		return;

	if (fmap_locate_area_as_rdev_rw(name, &rdev) < 0) {
		printk(BIOS_ERR, "MRC: Couldn't find '%s' region. Invalidation failed\n",
			name);
		return;
	}

	if (region_file_init(&cache_file, &rdev) < 0) {
		printk(BIOS_ERR, "MRC: region file invalid for '%s'. Invalidation failed\n",
			name);
		return;
	}

	/* Push an update that consists of 4 bytes that is smaller than the
	 * MRC metadata as well as an invalid signature. */
	if (region_file_update_data(&cache_file, &invalid, sizeof(invalid)) < 0)
		printk(BIOS_ERR, "MRC: invalidation failed for '%s'.\n", name);
}

static void update_mrc_cache(void *unused)
{
	update_mrc_cache_by_type(MRC_TRAINING_DATA);

	if (IS_ENABLED(CONFIG_MRC_SETTINGS_VARIABLE_DATA))
		update_mrc_cache_by_type(MRC_VARIABLE_DATA);

	if (IS_ENABLED(CONFIG_MRC_CLEAR_NORMAL_CACHE_ON_RECOVERY_RETRAIN))
		invalidate_normal_cache();

	protect_mrc_region();
}

BOOT_STATE_INIT_ENTRY(BS_WRITE_TABLES, BS_ON_ENTRY, update_mrc_cache, NULL);