summaryrefslogtreecommitdiff
path: root/src/drivers/elog/elog.c
blob: 59bc1de8d9e732ab9667f81081c8f741b3862ebb (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
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2012 The ChromiumOS Authors.  All rights reserved.
 *
 * 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.
 */

#if CONFIG_HAVE_ACPI_RESUME == 1
#include <arch/acpi.h>
#endif
#include <cbmem.h>
#include <console/console.h>
#if CONFIG_ARCH_X86
#include <pc80/mc146818rtc.h>
#endif
#include <bcd.h>
#include <boot_device.h>
#include <commonlib/region.h>
#include <fmap.h>
#include <rtc.h>
#include <smbios.h>
#include <spi-generic.h>
#include <spi_flash.h>
#include <stdint.h>
#include <string.h>
#include <elog.h>
#include "elog_internal.h"


#if CONFIG_ELOG_DEBUG
#define elog_debug(STR...) printk(BIOS_DEBUG, STR)
#else
#define elog_debug(STR...)
#endif

/*
 * Static variables for ELOG state
 */
static struct elog_area *elog_area;
static u16 total_size;
static u16 log_size; /* excluding header */
static u32 flash_base;
static u16 full_threshold; /* from end of header */
static u16 shrink_size; /* from end of header */

static elog_area_state area_state;
static elog_header_state header_state;
static elog_event_buffer_state event_buffer_state;

static u16 next_event_offset; /* from end of header */
static u16 event_count;

static struct spi_flash *elog_spi;

static enum {
	ELOG_UNINITIALIZED = 0,
	ELOG_INITIALIZED,
	ELOG_BROKEN,
} elog_initialized = ELOG_UNINITIALIZED;

/*
 * Pointer to an event log header in the event data area
 */
static inline struct event_header*
elog_get_event_base(u32 offset)
{
	return (struct event_header *)&elog_area->data[offset];
}

/*
 * Update the checksum at the last byte
 */
static void elog_update_checksum(struct event_header *event, u8 checksum)
{
	u8 *event_data = (u8*)event;
	event_data[event->length - 1] = checksum;
}

/*
 * Simple byte checksum for events
 */
static u8 elog_checksum_event(struct event_header *event)
{
	u8 index, checksum = 0;
	u8 *data = (u8*)event;

	for (index = 0; index < event->length; index++)
		checksum += data[index];
	return checksum;
}

/*
 * Check if a raw buffer is filled with ELOG_TYPE_EOL byte
 */
static int elog_is_buffer_clear(void *base, u32 size)
{
	u8 *current = base;
	u8 *end = current + size;

	elog_debug("elog_is_buffer_clear(base=0x%p size=%u)\n", base, size);

	for (; current != end; current++) {
		if (*current != ELOG_TYPE_EOL)
			return 0;
	}
	return 1;
}

/*
 * Check that the ELOG area has been initialized and is valid.
 */
static int elog_is_area_valid(void)
{
	elog_debug("elog_is_area_valid()\n");

	if (area_state != ELOG_AREA_HAS_CONTENT)
		return 0;
	if (header_state != ELOG_HEADER_VALID)
		return 0;
	if (event_buffer_state != ELOG_EVENT_BUFFER_OK)
		return 0;
	return 1;
}

/*
 * Verify the contents of an ELOG Header structure
 * Returns 1 if the header is valid, 0 otherwise
 */
static int elog_is_header_valid(struct elog_header *header)
{
	elog_debug("elog_is_header_valid()\n");

	if (header->magic != ELOG_SIGNATURE) {
		printk(BIOS_ERR, "ELOG: header magic 0x%X != 0x%X\n",
		       header->magic, ELOG_SIGNATURE);
		return 0;
	}
	if (header->version != ELOG_VERSION) {
		printk(BIOS_ERR, "ELOG: header version %u != %u\n",
		       header->version, ELOG_VERSION);
		return 0;
	}
	if (header->header_size != sizeof(*header)) {
		printk(BIOS_ERR, "ELOG: header size mismatch %u != %zu\n",
		       header->header_size, sizeof(*header));
		return 0;
	}
	return 1;
}

/*
 * Validate the event header and data.
 */
static int elog_is_event_valid(u32 offset)
{
	struct event_header *event;

	event = elog_get_event_base(offset);
	if (!event)
		return 0;

	/* Validate event length */
	if ((offsetof(struct event_header, type) +
	     sizeof(event->type) - 1 + offset) >= log_size)
		return 0;

	/* End of event marker has been found */
	if (event->type == ELOG_TYPE_EOL)
		return 0;

	/* Check if event fits in area */
	if ((offsetof(struct event_header, length) +
	     sizeof(event->length) - 1 + offset) >= log_size)
		return 0;

	/*
	 * If the current event length + the current offset exceeds
	 * the area size then the event area is corrupt.
	 */
	if ((event->length + offset) >= log_size)
		return 0;

	/* Event length must be at least header size + checksum */
	if (event->length < (sizeof(*event) + 1))
		return 0;

	/* If event checksum is invalid the area is corrupt */
	if (elog_checksum_event(event) != 0)
		return 0;

	/* Event is valid */
	return 1;
}

/*
 * Write 'size' bytes of data pointed to by 'address' in the flash backing
 * store into flash. This will not erase the flash and it assumes the flash
 * area has been erased appropriately.
 */
static void elog_flash_write(void *address, u32 size)
{
	u32 offset;

	if (!address || !size || !elog_spi)
		return;

	offset = flash_base;
	offset += (u8 *)address - (u8 *)elog_area;

	elog_debug("elog_flash_write(address=0x%p offset=0x%08x size=%u)\n",
		   address, offset, size);

	/* Write the data to flash */
	elog_spi->write(elog_spi, offset, size, address);
}

/*
 * Erase the first block specified in the address.
 * Only handles flash area within a single flash block.
 */
static void elog_flash_erase(void *address, u32 size)
{
	u32 offset;

	if (!address || !size || !elog_spi)
		return;

	offset = flash_base;
	offset += (u8 *)address - (u8*)elog_area;

	elog_debug("elog_flash_erase(address=0x%p offset=0x%08x size=%u)\n",
		   address, offset, size);

	/* Erase the sectors in this region */
	elog_spi->erase(elog_spi, offset, size);
}

/*
 * Scan the event area and validate each entry and update the ELOG state.
 */
static void elog_update_event_buffer_state(void)
{
	u32 count = 0;
	u32 offset = 0;
	struct event_header *event;

	elog_debug("elog_update_event_buffer_state()\n");

	/* Go through each event and validate it */
	while (1) {
		event = elog_get_event_base(offset);

		/* Do not de-reference anything past the area length */
		if ((offsetof(struct event_header, type) +
		     sizeof(event->type) - 1 + offset) >= log_size) {
			event_buffer_state = ELOG_EVENT_BUFFER_CORRUPTED;
			break;
		}

		/* The end of the event marker has been found */
		if (event->type == ELOG_TYPE_EOL)
			break;

		/* Validate the event */
		if (!elog_is_event_valid(offset)) {
			event_buffer_state = ELOG_EVENT_BUFFER_CORRUPTED;
			break;
		}

		/* Move to the next event */
		count++;
		offset += event->length;
	}

	/* Ensure the remaining buffer is empty */
	if (!elog_is_buffer_clear(&elog_area->data[offset], log_size - offset))
		event_buffer_state = ELOG_EVENT_BUFFER_CORRUPTED;

	/* Update ELOG state */
	event_count = count;
	next_event_offset = offset;
}

static void elog_scan_flash(void)
{
	elog_debug("elog_scan_flash()\n");

	area_state = ELOG_AREA_UNDEFINED;
	header_state = ELOG_HEADER_INVALID;
	event_buffer_state = ELOG_EVENT_BUFFER_OK;

	/* Fill memory buffer by reading from SPI */
	elog_spi->read(elog_spi, flash_base, total_size, elog_area);

	next_event_offset = 0;
	event_count = 0;

	/* Check if the area is empty or not */
	if (elog_is_buffer_clear(elog_area, total_size)) {
		area_state = ELOG_AREA_EMPTY;
		return;
	}

	area_state = ELOG_AREA_HAS_CONTENT;

	/* Validate the header */
	if (!elog_is_header_valid(&elog_area->header)) {
		header_state = ELOG_HEADER_INVALID;
		return;
	}

	header_state = ELOG_HEADER_VALID;
	elog_update_event_buffer_state();
}

static void elog_prepare_empty(void)
{
	struct elog_header *header;

	elog_debug("elog_prepare_empty()\n");

	/* Write out the header */
	header = &elog_area->header;
	header->magic = ELOG_SIGNATURE;
	header->version = ELOG_VERSION;
	header->header_size = sizeof(struct elog_header);
	header->reserved[0] = ELOG_TYPE_EOL;
	header->reserved[1] = ELOG_TYPE_EOL;
	elog_flash_write(elog_area, header->header_size);

	elog_scan_flash();
}

/*
 * Shrink the log, deleting old entries and moving the
 * remaining ones to the front of the log.
 */
static int elog_shrink(void)
{
	struct event_header *event;
	u16 discard_count = 0;
	u16 offset = 0;
	u16 new_size = 0;

	elog_debug("elog_shrink()\n");

	if (next_event_offset < shrink_size)
		return 0;

	while (1) {
		/* Next event has exceeded constraints */
		if (offset > shrink_size)
			break;

		event = elog_get_event_base(offset);

		/* Reached the end of the area */
		if (!event || event->type == ELOG_TYPE_EOL)
			break;

		offset += event->length;
		discard_count++;
	}

	new_size = next_event_offset - offset;
	memmove(&elog_area->data[0], &elog_area->data[offset], new_size);
	memset(&elog_area->data[new_size], ELOG_TYPE_EOL, log_size - new_size);

	elog_flash_erase(elog_area, total_size);
	elog_flash_write(elog_area, total_size);
	elog_scan_flash();

	/* Ensure the area was successfully erased */
	if (next_event_offset >= full_threshold) {
		printk(BIOS_ERR, "ELOG: Flash area was not erased!\n");
		return -1;
	}

	/* Add clear event */
	elog_add_event_word(ELOG_TYPE_LOG_CLEAR, offset);

	return 0;
}

#ifndef __SMM__
#if IS_ENABLED(CONFIG_ARCH_X86)

/*
 * Convert a flash offset into a memory mapped flash address
 */
static inline u8 *elog_flash_offset_to_address(void)
{
	/* Only support memory-mapped SPI devices. */
	if (!IS_ENABLED(CONFIG_SPI_FLASH_MEMORY_MAPPED))
		return NULL;

	if (!elog_spi)
		return NULL;

	return rdev_mmap(boot_device_ro(), flash_base, total_size);
}

/*
 * Fill out SMBIOS Type 15 table entry so the
 * event log can be discovered at runtime.
 */
int elog_smbios_write_type15(unsigned long *current, int handle)
{
	struct smbios_type15 *t = (struct smbios_type15 *)*current;
	int len = sizeof(struct smbios_type15);

#if CONFIG_ELOG_CBMEM
	/* Save event log buffer into CBMEM for the OS to read */
	void *cbmem = cbmem_add(CBMEM_ID_ELOG, total_size);
	if (!cbmem)
		return 0;
	memcpy(cbmem, elog_area, total_size);
#endif

	memset(t, 0, len);
	t->type = SMBIOS_EVENT_LOG;
	t->length = len - 2;
	t->handle = handle;
	t->area_length = total_size - 1;
	t->header_offset = 0;
	t->data_offset = sizeof(struct elog_header);
	t->access_method = SMBIOS_EVENTLOG_ACCESS_METHOD_MMIO32;
	t->log_status = SMBIOS_EVENTLOG_STATUS_VALID;
	t->change_token = 0;
#if CONFIG_ELOG_CBMEM
	t->address = (u32)cbmem;
#else
	t->address = (u32)elog_flash_offset_to_address();
#endif
	t->header_format = ELOG_HEADER_TYPE_OEM;
	t->log_type_descriptors = 0;
	t->log_type_descriptor_length = 2;

	*current += len;
	return len;
}
#endif
#endif

/*
 * Clear the entire event log
 */
int elog_clear(void)
{
	elog_debug("elog_clear()\n");

	/* Make sure ELOG structures are initialized */
	if (elog_init() < 0)
		return -1;

	/* Erase flash area */
	elog_flash_erase(elog_area, total_size);
	elog_prepare_empty();

	if (!elog_is_area_valid())
		return -1;

	/* Log the clear event */
	elog_add_event_word(ELOG_TYPE_LOG_CLEAR, log_size);

	return 0;
}

static void elog_find_flash(void)
{
	struct region r;

	elog_debug("elog_find_flash()\n");

	/* Find the ELOG base and size in FMAP */
	if (fmap_locate_area("RW_ELOG", &r) < 0) {
		printk(BIOS_WARNING, "ELOG: Unable to find RW_ELOG in FMAP\n");
		flash_base = total_size = 0;
	} else {
		flash_base = region_offset(&r);
		/* Keep 4KiB max size until large malloc()s have been fixed. */
		total_size = MIN(4*KiB, region_sz(&r));
	}

	log_size = total_size - sizeof(struct elog_header);
	full_threshold = log_size - ELOG_MIN_AVAILABLE_ENTRIES * MAX_EVENT_SIZE;
	shrink_size = MIN(total_size * ELOG_SHRINK_PERCENTAGE / 100,
								full_threshold);
}

/*
 * Event log main entry point
 */
int elog_init(void)
{
	switch (elog_initialized) {
	case ELOG_UNINITIALIZED:
		break;
	case ELOG_INITIALIZED:
		return 0;
	case ELOG_BROKEN:
		return -1;
	}
	elog_initialized = ELOG_BROKEN;

	elog_debug("elog_init()\n");

	/* Probe SPI chip. SPI controller must already be initialized. */
	elog_spi = spi_flash_probe(CONFIG_BOOT_MEDIA_SPI_BUS, 0);
	if (!elog_spi) {
		printk(BIOS_ERR, "ELOG: Unable to find SPI flash\n");
		return -1;
	}

	/* Set up the backing store */
	elog_find_flash();
	if (flash_base == 0) {
		printk(BIOS_ERR, "ELOG: Invalid flash base\n");
		return -1;
	} else if (total_size < sizeof(struct elog_header) + MAX_EVENT_SIZE) {
		printk(BIOS_ERR, "ELOG: Region too small to hold any events\n");
		return -1;
	} else if (log_size - shrink_size >= full_threshold) {
		printk(BIOS_ERR,
			"ELOG: SHRINK_PERCENTAGE set too small for MIN_AVAILABLE_ENTRIES\n");
		return -1;
	}

	elog_area = malloc(total_size);
	if (!elog_area) {
		printk(BIOS_ERR, "ELOG: Unable to allocate backing store\n");
		return -1;
	}

	/* Load the log from flash */
	elog_scan_flash();

	/* Prepare the flash if necessary */
	if (header_state == ELOG_HEADER_INVALID ||
		event_buffer_state == ELOG_EVENT_BUFFER_CORRUPTED) {
		/* If the header is invalid or the events are corrupted,
		 * no events can be salvaged so erase the entire area. */
		printk(BIOS_ERR, "ELOG: flash area invalid\n");
		elog_flash_erase(elog_area, total_size);
		elog_prepare_empty();
	}

	if (area_state == ELOG_AREA_EMPTY)
		elog_prepare_empty();

	if (!elog_is_area_valid()) {
		printk(BIOS_ERR, "ELOG: Unable to prepare flash\n");
		return -1;
	}

	printk(BIOS_INFO, "ELOG: FLASH @0x%p [SPI 0x%08x]\n",
	       elog_area, flash_base);

	printk(BIOS_INFO, "ELOG: area is %d bytes, full threshold %d,"
	       " shrink size %d\n", total_size, full_threshold, shrink_size);

	elog_initialized = ELOG_INITIALIZED;

	/* Shrink the log if we are getting too full */
	if (next_event_offset >= full_threshold)
		if (elog_shrink() < 0)
			return -1;

	/* Log a clear event if necessary */
	if (event_count == 0)
		elog_add_event_word(ELOG_TYPE_LOG_CLEAR, log_size);

#if !defined(__SMM__)
	/* Log boot count event except in S3 resume */
#if CONFIG_ELOG_BOOT_COUNT == 1
#if CONFIG_HAVE_ACPI_RESUME == 1
		if (!acpi_is_wakeup_s3())
#endif
		elog_add_event_dword(ELOG_TYPE_BOOT, boot_count_read());
#else
		/* If boot count is not implemented, fake it. */
		elog_add_event_dword(ELOG_TYPE_BOOT, 0);
#endif

#if CONFIG_ARCH_X86
	/* Check and log POST codes from previous boot */
	if (CONFIG_CMOS_POST)
		cmos_post_log();
#endif
#endif

	elog_initialized = ELOG_INITIALIZED;

	return 0;
}

/*
 * Populate timestamp in event header with current time
 */
static void elog_fill_timestamp(struct event_header *event)
{
#if IS_ENABLED(CONFIG_RTC)
	struct rtc_time time;

	rtc_get(&time);
	event->second = bin2bcd(time.sec);
	event->minute = bin2bcd(time.min);
	event->hour = bin2bcd(time.hour);
	event->day = bin2bcd(time.mday);
	event->month = bin2bcd(time.mon);
	event->year = bin2bcd(time.year % 100);

	/* Basic sanity check of expected ranges */
	if (event->month > 0x12 || event->day > 0x31 || event->hour > 0x23 ||
	    event->minute > 0x59 || event->second > 0x59)
#endif
	{
		event->year   = 0;
		event->month  = 0;
		event->day    = 0;
		event->hour   = 0;
		event->minute = 0;
		event->second = 0;
	}
}

/*
 * Add an event to the log
 */
void elog_add_event_raw(u8 event_type, void *data, u8 data_size)
{
	struct event_header *event;
	u8 event_size;

	elog_debug("elog_add_event_raw(type=%X)\n", event_type);

	/* Make sure ELOG structures are initialized */
	if (elog_init() < 0)
		return;

	/* Header + Data + Checksum */
	event_size = sizeof(*event) + data_size + 1;
	if (event_size > MAX_EVENT_SIZE) {
		printk(BIOS_ERR, "ELOG: Event(%X) data size too "
		       "big (%d)\n", event_type, event_size);
		return;
	}

	/* Make sure event data can fit */
	if ((next_event_offset + event_size) >= log_size) {
		printk(BIOS_ERR, "ELOG: Event(%X) does not fit\n",
		       event_type);
		return;
	}

	/* Fill out event data */
	event = elog_get_event_base(next_event_offset);
	event->type = event_type;
	event->length = event_size;
	elog_fill_timestamp(event);

	if (data_size)
		memcpy(&event[1], data, data_size);

	/* Zero the checksum byte and then compute checksum */
	elog_update_checksum(event, 0);
	elog_update_checksum(event, -(elog_checksum_event(event)));

	/* Update the ELOG state */
	event_count++;

	elog_flash_write((void *)event, event_size);

	next_event_offset += event_size;

	printk(BIOS_INFO, "ELOG: Event(%X) added with size %d\n",
	       event_type, event_size);

	/* Shrink the log if we are getting too full */
	if (next_event_offset >= full_threshold)
		elog_shrink();
}

void elog_add_event(u8 event_type)
{
	elog_add_event_raw(event_type, NULL, 0);
}

void elog_add_event_byte(u8 event_type, u8 data)
{
	elog_add_event_raw(event_type, &data, sizeof(data));
}

void elog_add_event_word(u8 event_type, u16 data)
{
	elog_add_event_raw(event_type, &data, sizeof(data));
}

void elog_add_event_dword(u8 event_type, u32 data)
{
	elog_add_event_raw(event_type, &data, sizeof(data));
}

void elog_add_event_wake(u8 source, u32 instance)
{
	struct elog_event_data_wake wake = {
		.source = source,
		.instance = instance
	};
	elog_add_event_raw(ELOG_TYPE_WAKE_SOURCE, &wake, sizeof(wake));
}