summaryrefslogtreecommitdiff
path: root/src/boot/selfboot.c
blob: 7ae9f8cd7d5541969d05e3954aee20ddc2614390 (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
/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2003 Eric W. Biederman <ebiederm@xmission.com>
 * Copyright (C) 2009 Ron Minnich <rminnich@gmail.com>
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
 */

#include <arch/byteorder.h>
#include <console/console.h>
#include <fallback.h>
#include <boot/elf.h>
#include <boot/elf_boot.h>
#include <boot/coreboot_tables.h>
#include <ip_checksum.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <cbfs.h>
#include <lib.h>

/* Maximum physical address we can use for the coreboot bounce buffer.
 */
#ifndef MAX_ADDR
#define MAX_ADDR -1UL
#endif

extern unsigned char _ram_seg;
extern unsigned char _eram_seg;

struct segment {
	struct segment *next;
	struct segment *prev;
	struct segment *phdr_next;
	struct segment *phdr_prev;
	unsigned long s_dstaddr;
	unsigned long s_srcaddr;
	unsigned long s_memsz;
	unsigned long s_filesz;
	int compression;
};

struct verify_callback {
	struct verify_callback *next;
	int (*callback)(struct verify_callback *vcb,
		Elf_ehdr *ehdr, Elf_phdr *phdr, struct segment *head);
	unsigned long desc_offset;
	unsigned long desc_addr;
};

struct ip_checksum_vcb {
	struct verify_callback data;
	unsigned short ip_checksum;
};

static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload);

void * cbfs_load_payload(struct lb_memory *lb_mem, const char *name)
{
	struct cbfs_payload *payload;

	payload = (struct cbfs_payload *)cbfs_find_file(name, CBFS_TYPE_PAYLOAD);
	if (payload == NULL)
		return (void *) -1;
	printk(BIOS_DEBUG, "Got a payload\n");

	selfboot(lb_mem, payload);
	printk(BIOS_EMERG, "SELFBOOT RETURNED!\n");

	return (void *) -1;
}

/* The problem:
 * Static executables all want to share the same addresses
 * in memory because only a few addresses are reliably present on
 * a machine, and implementing general relocation is hard.
 *
 * The solution:
 * - Allocate a buffer the size of the coreboot image plus additional
 *   required space.
 * - Anything that would overwrite coreboot copy into the lower part of
 *   the buffer.
 * - After loading an ELF image copy coreboot to the top of the buffer.
 * - Then jump to the loaded image.
 *
 * Benefits:
 * - Nearly arbitrary standalone executables can be loaded.
 * - Coreboot is preserved, so it can be returned to.
 * - The implementation is still relatively simple,
 *   and much simpler than the general case implemented in kexec.
 *
 */

static unsigned long bounce_size, bounce_buffer;

static void get_bounce_buffer(struct lb_memory *mem, unsigned long req_size)
{
	unsigned long lb_size;
	unsigned long mem_entries;
	unsigned long buffer;
	int i;
	lb_size = (unsigned long)(&_eram_seg - &_ram_seg);
	/* Double coreboot size so I have somewhere to place a copy to return to */
	lb_size = req_size + lb_size;
	mem_entries = (mem->size - sizeof(*mem))/sizeof(mem->map[0]);
	buffer = 0;
	for(i = 0; i < mem_entries; i++) {
		unsigned long mstart, mend;
		unsigned long msize;
		unsigned long tbuffer;
		if (mem->map[i].type != LB_MEM_RAM)
			continue;
		if (unpack_lb64(mem->map[i].start) > MAX_ADDR)
			continue;
		if (unpack_lb64(mem->map[i].size) < lb_size)
			continue;
		mstart = unpack_lb64(mem->map[i].start);
		msize = MAX_ADDR - mstart +1;
		if (msize > unpack_lb64(mem->map[i].size))
			msize = unpack_lb64(mem->map[i].size);
		mend = mstart + msize;
		tbuffer = mend - lb_size;
		if (tbuffer < buffer)
			continue;
		buffer = tbuffer;
	}
	bounce_buffer = buffer;
	bounce_size = req_size;
}

static int valid_area(struct lb_memory *mem, unsigned long buffer,
	unsigned long start, unsigned long len)
{
	/* Check through all of the memory segments and ensure
	 * the segment that was passed in is completely contained
	 * in RAM.
	 */
	int i;
	unsigned long end = start + len;
	unsigned long mem_entries = (mem->size - sizeof(*mem))/sizeof(mem->map[0]);

	/* See if I conflict with the bounce buffer */
	if (end >= buffer) {
		return 0;
	}

	/* Walk through the table of valid memory ranges and see if I
	 * have a match.
	 */
	for(i = 0; i < mem_entries; i++) {
		uint64_t mstart, mend;
		uint32_t mtype;
		mtype = mem->map[i].type;
		mstart = unpack_lb64(mem->map[i].start);
		mend = mstart + unpack_lb64(mem->map[i].size);
		if ((mtype == LB_MEM_RAM) && (start < mend) && (end > mstart)) {
			break;
		}
		if ((mtype == LB_MEM_TABLE) && (start < mend) && (end > mstart)) {
			printk(BIOS_ERR, "Payload is overwriting coreboot tables.\n");
			break;
		}
	}
	if (i == mem_entries) {
		printk(BIOS_ERR, "No matching ram area found for range:\n");
		printk(BIOS_ERR, "  [0x%016lx, 0x%016lx)\n", start, end);
		printk(BIOS_ERR, "Ram areas\n");
		for(i = 0; i < mem_entries; i++) {
			uint64_t mstart, mend;
			uint32_t mtype;
			mtype = mem->map[i].type;
			mstart = unpack_lb64(mem->map[i].start);
			mend = mstart + unpack_lb64(mem->map[i].size);
			printk(BIOS_ERR, "  [0x%016lx, 0x%016lx) %s\n",
				(unsigned long)mstart,
				(unsigned long)mend,
				(mtype == LB_MEM_RAM)?"RAM":"Reserved");

		}
		return 0;
	}
	return 1;
}

static const unsigned long lb_start = (unsigned long)&_ram_seg;
static const unsigned long lb_end = (unsigned long)&_eram_seg;

static int overlaps_coreboot(struct segment *seg)
{
	unsigned long start, end;
	start = seg->s_dstaddr;
	end = start + seg->s_memsz;
	return !((end <= lb_start) || (start >= lb_end));
}

static int relocate_segment(unsigned long buffer, struct segment *seg)
{
	/* Modify all segments that want to load onto coreboot
	 * to load onto the bounce buffer instead.
	 */
	/* ret:  1 : A new segment is inserted before the seg.
	 *       0 : A new segment is inserted after the seg, or no new one. */
	unsigned long start, middle, end, ret = 0;

	printk(BIOS_SPEW, "lb: [0x%016lx, 0x%016lx)\n",
		lb_start, lb_end);

	/* I don't conflict with coreboot so get out of here */
	if (!overlaps_coreboot(seg))
		return 0;

	start = seg->s_dstaddr;
	middle = start + seg->s_filesz;
	end = start + seg->s_memsz;

	printk(BIOS_SPEW, "segment: [0x%016lx, 0x%016lx, 0x%016lx)\n",
		start, middle, end);

	if (seg->compression == CBFS_COMPRESS_NONE) {
		/* Slice off a piece at the beginning
		 * that doesn't conflict with coreboot.
		 */
		if (start < lb_start) {
			struct segment *new;
			unsigned long len = lb_start - start;
			new = malloc(sizeof(*new));
			*new = *seg;
			new->s_memsz = len;
			seg->s_memsz -= len;
			seg->s_dstaddr += len;
			seg->s_srcaddr += len;
			if (seg->s_filesz > len) {
				new->s_filesz = len;
				seg->s_filesz -= len;
			} else {
				seg->s_filesz = 0;
			}

			/* Order by stream offset */
			new->next = seg;
			new->prev = seg->prev;
			seg->prev->next = new;
			seg->prev = new;
			/* Order by original program header order */
			new->phdr_next = seg;
			new->phdr_prev = seg->phdr_prev;
			seg->phdr_prev->phdr_next = new;
			seg->phdr_prev = new;

			/* compute the new value of start */
			start = seg->s_dstaddr;

			printk(BIOS_SPEW, "   early: [0x%016lx, 0x%016lx, 0x%016lx)\n",
				new->s_dstaddr,
				new->s_dstaddr + new->s_filesz,
				new->s_dstaddr + new->s_memsz);

			ret = 1;
		}

		/* Slice off a piece at the end
		 * that doesn't conflict with coreboot
		 */
		if (end > lb_end) {
			unsigned long len = lb_end - start;
			struct segment *new;
			new = malloc(sizeof(*new));
			*new = *seg;
			seg->s_memsz = len;
			new->s_memsz -= len;
			new->s_dstaddr += len;
			new->s_srcaddr += len;
			if (seg->s_filesz > len) {
				seg->s_filesz = len;
				new->s_filesz -= len;
			} else {
				new->s_filesz = 0;
			}
			/* Order by stream offset */
			new->next = seg->next;
			new->prev = seg;
			seg->next->prev = new;
			seg->next = new;
			/* Order by original program header order */
			new->phdr_next = seg->phdr_next;
			new->phdr_prev = seg;
			seg->phdr_next->phdr_prev = new;
			seg->phdr_next = new;

			printk(BIOS_SPEW, "   late: [0x%016lx, 0x%016lx, 0x%016lx)\n",
				new->s_dstaddr,
				new->s_dstaddr + new->s_filesz,
				new->s_dstaddr + new->s_memsz);
		}
	}

	/* Now retarget this segment onto the bounce buffer */
	/* sort of explanation: the buffer is a 1:1 mapping to coreboot.
	 * so you will make the dstaddr be this buffer, and it will get copied
	 * later to where coreboot lives.
	 */
	seg->s_dstaddr = buffer + (seg->s_dstaddr - lb_start);

	printk(BIOS_SPEW, " bounce: [0x%016lx, 0x%016lx, 0x%016lx)\n",
		seg->s_dstaddr,
		seg->s_dstaddr + seg->s_filesz,
		seg->s_dstaddr + seg->s_memsz);

	return ret;
}


static int build_self_segment_list(
	struct segment *head,
	struct lb_memory *mem,
	struct cbfs_payload *payload, u32 *entry)
{
	struct segment *new;
	struct segment *ptr;
	struct cbfs_payload_segment *segment, *first_segment;
	memset(head, 0, sizeof(*head));
	head->phdr_next = head->phdr_prev = head;
	head->next = head->prev = head;
	first_segment = segment = &payload->segments;

	while(1) {
		printk(BIOS_DEBUG, "Loading segment from rom address 0x%p\n", segment);
		switch(segment->type) {
		case PAYLOAD_SEGMENT_PARAMS:
			printk(BIOS_DEBUG, "  parameter section (skipped)\n");
			segment++;
			continue;

		case PAYLOAD_SEGMENT_CODE:
		case PAYLOAD_SEGMENT_DATA:
			printk(BIOS_DEBUG, "  %s (compression=%x)\n",
					segment->type == PAYLOAD_SEGMENT_CODE ?  "code" : "data",
					ntohl(segment->compression));
			new = malloc(sizeof(*new));
			new->s_dstaddr = ntohl((u32) segment->load_addr);
			new->s_memsz = ntohl(segment->mem_len);
			new->compression = ntohl(segment->compression);

			new->s_srcaddr = (u32) ((unsigned char *) first_segment) + ntohl(segment->offset);
			new->s_filesz = ntohl(segment->len);
			printk(BIOS_DEBUG, "  New segment dstaddr 0x%lx memsize 0x%lx srcaddr 0x%lx filesize 0x%lx\n",
				new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
			/* Clean up the values */
			if (new->s_filesz > new->s_memsz)  {
				new->s_filesz = new->s_memsz;
			}
			printk(BIOS_DEBUG, "  (cleaned up) New segment addr 0x%lx size 0x%lx offset 0x%lx filesize 0x%lx\n",
				new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
			break;

		case PAYLOAD_SEGMENT_BSS:
			printk(BIOS_DEBUG, "  BSS 0x%p (%d byte)\n", (void *) ntohl((u32) segment->load_addr),
				 ntohl(segment->mem_len));
			new = malloc(sizeof(*new));
			new->s_filesz = 0;
			new->s_dstaddr = ntohl((u32) segment->load_addr);
			new->s_memsz = ntohl(segment->mem_len);
			break;

		case PAYLOAD_SEGMENT_ENTRY:
			printk(BIOS_DEBUG, "  Entry Point 0x%p\n", (void *) ntohl((u32) segment->load_addr));
			*entry =  ntohl((u32) segment->load_addr);
			/* Per definition, a payload always has the entry point
			 * as last segment. Thus, we use the occurence of the
			 * entry point as break condition for the loop.
			 * Can we actually just look at the number of section?
			 */
			return 1;

		default:
			/* We found something that we don't know about. Throw
			 * hands into the sky and run away!
			 */
			printk(BIOS_EMERG, "Bad segment type %x\n", segment->type);
			return -1;
		}

		segment++;

		// FIXME: Explain what this is
		for(ptr = head->next; ptr != head; ptr = ptr->next) {
			if (new->s_srcaddr < ntohl((u32) segment->load_addr))
				break;
		}

		/* Order by stream offset */
		new->next = ptr;
		new->prev = ptr->prev;
		ptr->prev->next = new;
		ptr->prev = new;

		/* Order by original program header order */
		new->phdr_next = head;
		new->phdr_prev = head->phdr_prev;
		head->phdr_prev->phdr_next  = new;
		head->phdr_prev = new;
	}

	return 1;
}

static int load_self_segments(
	struct segment *head,
	struct lb_memory *mem,
	struct cbfs_payload *payload)
{
	struct segment *ptr;

	unsigned long bounce_high = lb_end;
	for(ptr = head->next; ptr != head; ptr = ptr->next) {
		if (!overlaps_coreboot(ptr)) continue;
		if (ptr->s_dstaddr + ptr->s_memsz > bounce_high)
			bounce_high = ptr->s_dstaddr + ptr->s_memsz;
	}
	get_bounce_buffer(mem, bounce_high - lb_start);
	if (!bounce_buffer) {
		printk(BIOS_ERR, "Could not find a bounce buffer...\n");
		return 0;
	}
	for(ptr = head->next; ptr != head; ptr = ptr->next) {
		/* Verify the memory addresses in the segment are valid */
		if (!valid_area(mem, bounce_buffer, ptr->s_dstaddr, ptr->s_memsz))
			return 0;
	}
	for(ptr = head->next; ptr != head; ptr = ptr->next) {
		unsigned char *dest, *src;
		printk(BIOS_DEBUG, "Loading Segment: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
			ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);

		/* Modify the segment to load onto the bounce_buffer if necessary.
		 */
		if (relocate_segment(bounce_buffer, ptr)) {
			ptr = (ptr->prev)->prev;
			continue;
		}

		printk(BIOS_DEBUG, "Post relocation: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
			ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);

		/* Compute the boundaries of the segment */
		dest = (unsigned char *)(ptr->s_dstaddr);
		src = (unsigned char *)(ptr->s_srcaddr);

		/* Copy data from the initial buffer */
		if (ptr->s_filesz) {
			unsigned char *middle, *end;
			size_t len;
			len = ptr->s_filesz;
			switch(ptr->compression) {
				case CBFS_COMPRESS_LZMA: {
					printk(BIOS_DEBUG, "using LZMA\n");
					len = ulzma(src, dest);
					if (!len) /* Decompression Error. */
						return 0;
					break;
				}
#if CONFIG_COMPRESSED_PAYLOAD_NRV2B
				case CBFS_COMPRESS_NRV2B: {
					printk(BIOS_DEBUG, "using NRV2B\n");
					unsigned long unrv2b(u8 *src, u8 *dst, unsigned long *ilen_p);
					unsigned long tmp;
					len = unrv2b(src, dest, &tmp);
					break;
				}
#endif
				case CBFS_COMPRESS_NONE: {
					printk(BIOS_DEBUG, "it's not compressed!\n");
					memcpy(dest, src, len);
					break;
				}
				default:
					printk(BIOS_INFO,  "CBFS:  Unknown compression type %d\n", ptr->compression);
					return -1;
			}
			end = dest + ptr->s_memsz;
			middle = dest + len;
			printk(BIOS_SPEW, "[ 0x%08lx, %08lx, 0x%08lx) <- %08lx\n",
				(unsigned long)dest,
				(unsigned long)middle,
				(unsigned long)end,
				(unsigned long)src);

			/* Zero the extra bytes between middle & end */
			if (middle < end) {
				printk(BIOS_DEBUG, "Clearing Segment: addr: 0x%016lx memsz: 0x%016lx\n",
					(unsigned long)middle, (unsigned long)(end - middle));

				/* Zero the extra bytes */
				memset(middle, 0, end - middle);
			}
			/* Copy the data that's outside the area that shadows coreboot_ram */
			printk(BIOS_DEBUG, "dest %p, end %p, bouncebuffer %lx\n", dest, end, bounce_buffer);
			if ((unsigned long)end > bounce_buffer) {
				if ((unsigned long)dest < bounce_buffer) {
					unsigned char *from = dest;
					unsigned char *to = (unsigned char*)(lb_start-(bounce_buffer-(unsigned long)dest));
					unsigned long amount = bounce_buffer-(unsigned long)dest;
					printk(BIOS_DEBUG, "move prefix around: from %p, to %p, amount: %lx\n", from, to, amount);
					memcpy(to, from, amount);
				}
				if ((unsigned long)end > bounce_buffer + (lb_end - lb_start)) {
					unsigned long from = bounce_buffer + (lb_end - lb_start);
					unsigned long to = lb_end;
					unsigned long amount = (unsigned long)end - from;
					printk(BIOS_DEBUG, "move suffix around: from %lx, to %lx, amount: %lx\n", from, to, amount);
					memcpy((char*)to, (char*)from, amount);
				}
			}
		}
	}
	return 1;
}

static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload)
{
	u32 entry=0;
	struct segment head;

	/* Preprocess the self segments */
	if (!build_self_segment_list(&head, mem, payload, &entry))
		goto out;

	/* Load the segments */
	if (!load_self_segments(&head, mem, payload))
		goto out;

	printk(BIOS_SPEW, "Loaded segments\n");

	/* Reset to booting from this image as late as possible */
	boot_successful();

	printk(BIOS_DEBUG, "Jumping to boot code at %x\n", entry);
	post_code(POST_ENTER_ELF_BOOT);

	/* Jump to kernel */
	jmp_to_elf_entry((void*)entry, bounce_buffer, bounce_size);
	return 1;

 out:
	return 0;
}