summaryrefslogtreecommitdiff
path: root/lib/efi_loader/efi_device_path.c
blob: 24a4f40c004dd2f8890d76633d7c983ff3197545 (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
/*
 * EFI device path from u-boot device-model mapping
 *
 * (C) Copyright 2017 Rob Clark
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <blk.h>
#include <dm.h>
#include <usb.h>
#include <mmc.h>
#include <efi_loader.h>
#include <inttypes.h>
#include <part.h>

/* template END node: */
static const struct efi_device_path END = {
	.type     = DEVICE_PATH_TYPE_END,
	.sub_type = DEVICE_PATH_SUB_TYPE_END,
	.length   = sizeof(END),
};

#define U_BOOT_GUID \
	EFI_GUID(0xe61d73b9, 0xa384, 0x4acc, \
		 0xae, 0xab, 0x82, 0xe8, 0x28, 0xf3, 0x62, 0x8b)

/* template ROOT node: */
static const struct efi_device_path_vendor ROOT = {
	.dp = {
		.type     = DEVICE_PATH_TYPE_HARDWARE_DEVICE,
		.sub_type = DEVICE_PATH_SUB_TYPE_VENDOR,
		.length   = sizeof(ROOT),
	},
	.guid = U_BOOT_GUID,
};

static void *dp_alloc(size_t sz)
{
	void *buf;

	if (efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, sz, &buf) != EFI_SUCCESS)
		return NULL;

	return buf;
}

/*
 * Iterate to next block in device-path, terminating (returning NULL)
 * at /End* node.
 */
struct efi_device_path *efi_dp_next(const struct efi_device_path *dp)
{
	if (dp == NULL)
		return NULL;
	if (dp->type == DEVICE_PATH_TYPE_END)
		return NULL;
	dp = ((void *)dp) + dp->length;
	if (dp->type == DEVICE_PATH_TYPE_END)
		return NULL;
	return (struct efi_device_path *)dp;
}

/*
 * Compare two device-paths, stopping when the shorter of the two hits
 * an End* node.  This is useful to, for example, compare a device-path
 * representing a device with one representing a file on the device, or
 * a device with a parent device.
 */
int efi_dp_match(const struct efi_device_path *a,
		 const struct efi_device_path *b)
{
	while (1) {
		int ret;

		ret = memcmp(&a->length, &b->length, sizeof(a->length));
		if (ret)
			return ret;

		ret = memcmp(a, b, a->length);
		if (ret)
			return ret;

		a = efi_dp_next(a);
		b = efi_dp_next(b);

		if (!a || !b)
			return 0;
	}
}


/*
 * See UEFI spec (section 3.1.2, about short-form device-paths..
 * tl;dr: we can have a device-path that starts with a USB WWID
 * or USB Class node, and a few other cases which don't encode
 * the full device path with bus hierarchy:
 *
 *   - MESSAGING:USB_WWID
 *   - MESSAGING:USB_CLASS
 *   - MEDIA:FILE_PATH
 *   - MEDIA:HARD_DRIVE
 *   - MESSAGING:URI
 */
static struct efi_device_path *shorten_path(struct efi_device_path *dp)
{
	while (dp) {
		/*
		 * TODO: Add MESSAGING:USB_WWID and MESSAGING:URI..
		 * in practice fallback.efi just uses MEDIA:HARD_DRIVE
		 * so not sure when we would see these other cases.
		 */
		if (EFI_DP_TYPE(dp, MESSAGING_DEVICE, MSG_USB_CLASS) ||
		    EFI_DP_TYPE(dp, MEDIA_DEVICE, HARD_DRIVE_PATH) ||
		    EFI_DP_TYPE(dp, MEDIA_DEVICE, FILE_PATH))
			return dp;

		dp = efi_dp_next(dp);
	}

	return dp;
}

static struct efi_object *find_obj(struct efi_device_path *dp, bool short_path,
				   struct efi_device_path **rem)
{
	struct efi_object *efiobj;
	unsigned int dp_size = efi_dp_size(dp);

	list_for_each_entry(efiobj, &efi_obj_list, link) {
		struct efi_handler *handler;
		struct efi_device_path *obj_dp;
		efi_status_t ret;

		ret = efi_search_protocol(efiobj->handle,
					  &efi_guid_device_path, &handler);
		if (ret != EFI_SUCCESS)
			continue;
		obj_dp = handler->protocol_interface;

		do {
			if (efi_dp_match(dp, obj_dp) == 0) {
				if (rem) {
					/*
					 * Allow partial matches, but inform
					 * the caller.
					 */
					*rem = ((void *)dp) +
						efi_dp_size(obj_dp);
					return efiobj;
				} else {
					/* Only return on exact matches */
					if (efi_dp_size(obj_dp) == dp_size)
						return efiobj;
				}
			}

			obj_dp = shorten_path(efi_dp_next(obj_dp));
		} while (short_path && obj_dp);
	}

	return NULL;
}


/*
 * Find an efiobj from device-path, if 'rem' is not NULL, returns the
 * remaining part of the device path after the matched object.
 */
struct efi_object *efi_dp_find_obj(struct efi_device_path *dp,
				   struct efi_device_path **rem)
{
	struct efi_object *efiobj;

	/* Search for an exact match first */
	efiobj = find_obj(dp, false, NULL);

	/* Then for a fuzzy match */
	if (!efiobj)
		efiobj = find_obj(dp, false, rem);

	/* And now for a fuzzy short match */
	if (!efiobj)
		efiobj = find_obj(dp, true, rem);

	return efiobj;
}

/* return size not including End node: */
unsigned efi_dp_size(const struct efi_device_path *dp)
{
	unsigned sz = 0;

	while (dp) {
		sz += dp->length;
		dp = efi_dp_next(dp);
	}

	return sz;
}

struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp)
{
	struct efi_device_path *ndp;
	unsigned sz = efi_dp_size(dp) + sizeof(END);

	if (!dp)
		return NULL;

	ndp = dp_alloc(sz);
	memcpy(ndp, dp, sz);

	return ndp;
}

struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
				      const struct efi_device_path *dp2)
{
	struct efi_device_path *ret;

	if (!dp1) {
		ret = efi_dp_dup(dp2);
	} else if (!dp2) {
		ret = efi_dp_dup(dp1);
	} else {
		/* both dp1 and dp2 are non-null */
		unsigned sz1 = efi_dp_size(dp1);
		unsigned sz2 = efi_dp_size(dp2);
		void *p = dp_alloc(sz1 + sz2 + sizeof(END));
		memcpy(p, dp1, sz1);
		memcpy(p + sz1, dp2, sz2);
		memcpy(p + sz1 + sz2, &END, sizeof(END));
		ret = p;
	}

	return ret;
}

struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
					   const struct efi_device_path *node)
{
	struct efi_device_path *ret;

	if (!node && !dp) {
		ret = efi_dp_dup(&END);
	} else if (!node) {
		ret = efi_dp_dup(dp);
	} else if (!dp) {
		unsigned sz = node->length;
		void *p = dp_alloc(sz + sizeof(END));
		memcpy(p, node, sz);
		memcpy(p + sz, &END, sizeof(END));
		ret = p;
	} else {
		/* both dp and node are non-null */
		unsigned sz = efi_dp_size(dp);
		void *p = dp_alloc(sz + node->length + sizeof(END));
		memcpy(p, dp, sz);
		memcpy(p + sz, node, node->length);
		memcpy(p + sz + node->length, &END, sizeof(END));
		ret = p;
	}

	return ret;
}

#ifdef CONFIG_DM
/* size of device-path not including END node for device and all parents
 * up to the root device.
 */
static unsigned dp_size(struct udevice *dev)
{
	if (!dev || !dev->driver)
		return sizeof(ROOT);

	switch (dev->driver->id) {
	case UCLASS_ROOT:
	case UCLASS_SIMPLE_BUS:
		/* stop traversing parents at this point: */
		return sizeof(ROOT);
	case UCLASS_MMC:
		return dp_size(dev->parent) +
			sizeof(struct efi_device_path_sd_mmc_path);
	case UCLASS_MASS_STORAGE:
	case UCLASS_USB_HUB:
		return dp_size(dev->parent) +
			sizeof(struct efi_device_path_usb_class);
	default:
		/* just skip over unknown classes: */
		return dp_size(dev->parent);
	}
}

static void *dp_fill(void *buf, struct udevice *dev)
{
	if (!dev || !dev->driver)
		return buf;

	switch (dev->driver->id) {
	case UCLASS_ROOT:
	case UCLASS_SIMPLE_BUS: {
		/* stop traversing parents at this point: */
		struct efi_device_path_vendor *vdp = buf;
		*vdp = ROOT;
		return &vdp[1];
	}
#if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
	case UCLASS_MMC: {
		struct efi_device_path_sd_mmc_path *sddp =
			dp_fill(buf, dev->parent);
		struct mmc *mmc = mmc_get_mmc_dev(dev);
		struct blk_desc *desc = mmc_get_blk_desc(mmc);

		sddp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
		sddp->dp.sub_type = (desc->if_type == IF_TYPE_MMC) ?
			DEVICE_PATH_SUB_TYPE_MSG_MMC :
			DEVICE_PATH_SUB_TYPE_MSG_SD;
		sddp->dp.length   = sizeof(*sddp);
		sddp->slot_number = dev->seq;

		return &sddp[1];
	}
#endif
	case UCLASS_MASS_STORAGE:
	case UCLASS_USB_HUB: {
		struct efi_device_path_usb_class *udp =
			dp_fill(buf, dev->parent);
		struct usb_device *udev = dev_get_parent_priv(dev);
		struct usb_device_descriptor *desc = &udev->descriptor;

		udp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
		udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS;
		udp->dp.length   = sizeof(*udp);
		udp->vendor_id   = desc->idVendor;
		udp->product_id  = desc->idProduct;
		udp->device_class    = desc->bDeviceClass;
		udp->device_subclass = desc->bDeviceSubClass;
		udp->device_protocol = desc->bDeviceProtocol;

		return &udp[1];
	}
	default:
		debug("unhandled device class: %s (%u)\n",
		      dev->name, dev->driver->id);
		return dp_fill(buf, dev->parent);
	}
}

/* Construct a device-path from a device: */
struct efi_device_path *efi_dp_from_dev(struct udevice *dev)
{
	void *buf, *start;

	start = buf = dp_alloc(dp_size(dev) + sizeof(END));
	buf = dp_fill(buf, dev);
	*((struct efi_device_path *)buf) = END;

	return start;
}
#endif

static unsigned dp_part_size(struct blk_desc *desc, int part)
{
	unsigned dpsize;

#ifdef CONFIG_BLK
	dpsize = dp_size(desc->bdev->parent);
#else
	dpsize = sizeof(ROOT) + sizeof(struct efi_device_path_usb);
#endif

	if (part == 0) /* the actual disk, not a partition */
		return dpsize;

	if (desc->part_type == PART_TYPE_ISO)
		dpsize += sizeof(struct efi_device_path_cdrom_path);
	else
		dpsize += sizeof(struct efi_device_path_hard_drive_path);

	return dpsize;
}

static void *dp_part_fill(void *buf, struct blk_desc *desc, int part)
{
	disk_partition_t info;

#ifdef CONFIG_BLK
	buf = dp_fill(buf, desc->bdev->parent);
#else
	/*
	 * We *could* make a more accurate path, by looking at if_type
	 * and handling all the different cases like we do for non-
	 * legacy (ie CONFIG_BLK=y) case.  But most important thing
	 * is just to have a unique device-path for if_type+devnum.
	 * So map things to a fictional USB device:
	 */
	struct efi_device_path_usb *udp;

	memcpy(buf, &ROOT, sizeof(ROOT));
	buf += sizeof(ROOT);

	udp = buf;
	udp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
	udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB;
	udp->dp.length = sizeof(*udp);
	udp->parent_port_number = desc->if_type;
	udp->usb_interface = desc->devnum;
	buf = &udp[1];
#endif

	if (part == 0) /* the actual disk, not a partition */
		return buf;

	part_get_info(desc, part, &info);

	if (desc->part_type == PART_TYPE_ISO) {
		struct efi_device_path_cdrom_path *cddp = buf;

		cddp->boot_entry = part - 1;
		cddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
		cddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_CDROM_PATH;
		cddp->dp.length = sizeof(*cddp);
		cddp->partition_start = info.start;
		cddp->partition_end = info.size;

		buf = &cddp[1];
	} else {
		struct efi_device_path_hard_drive_path *hddp = buf;

		hddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
		hddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH;
		hddp->dp.length = sizeof(*hddp);
		hddp->partition_number = part - 1;
		hddp->partition_start = info.start;
		hddp->partition_end = info.size;
		if (desc->part_type == PART_TYPE_EFI)
			hddp->partmap_type = 2;
		else
			hddp->partmap_type = 1;

		switch (desc->sig_type) {
		case SIG_TYPE_NONE:
		default:
			hddp->signature_type = 0;
			memset(hddp->partition_signature, 0,
			       sizeof(hddp->partition_signature));
			break;
		case SIG_TYPE_MBR:
			hddp->signature_type = 1;
			memset(hddp->partition_signature, 0,
			       sizeof(hddp->partition_signature));
			memcpy(hddp->partition_signature, &desc->mbr_sig,
			       sizeof(desc->mbr_sig));
			break;
		case SIG_TYPE_GUID:
			hddp->signature_type = 2;
			memcpy(hddp->partition_signature, &desc->guid_sig,
			       sizeof(hddp->partition_signature));
			break;
		}

		buf = &hddp[1];
	}

	return buf;
}


/* Construct a device-path from a partition on a blk device: */
struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part)
{
	void *buf, *start;

	start = buf = dp_alloc(dp_part_size(desc, part) + sizeof(END));

	buf = dp_part_fill(buf, desc, part);

	*((struct efi_device_path *)buf) = END;

	return start;
}

/* convert path to an UEFI style path (ie. DOS style backslashes and utf16) */
static void path_to_uefi(u16 *uefi, const char *path)
{
	while (*path) {
		char c = *(path++);
		if (c == '/')
			c = '\\';
		*(uefi++) = c;
	}
	*uefi = '\0';
}

/*
 * If desc is NULL, this creates a path with only the file component,
 * otherwise it creates a full path with both device and file components
 */
struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
		const char *path)
{
	struct efi_device_path_file_path *fp;
	void *buf, *start;
	unsigned dpsize = 0, fpsize;

	if (desc)
		dpsize = dp_part_size(desc, part);

	fpsize = sizeof(struct efi_device_path) + 2 * (strlen(path) + 1);
	dpsize += fpsize;

	start = buf = dp_alloc(dpsize + sizeof(END));

	if (desc)
		buf = dp_part_fill(buf, desc, part);

	/* add file-path: */
	fp = buf;
	fp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
	fp->dp.sub_type = DEVICE_PATH_SUB_TYPE_FILE_PATH;
	fp->dp.length = fpsize;
	path_to_uefi(fp->str, path);
	buf += fpsize;

	*((struct efi_device_path *)buf) = END;

	return start;
}

#ifdef CONFIG_NET
struct efi_device_path *efi_dp_from_eth(void)
{
	struct efi_device_path_mac_addr *ndp;
	void *buf, *start;
	unsigned dpsize = 0;

	assert(eth_get_dev());

#ifdef CONFIG_DM_ETH
	dpsize += dp_size(eth_get_dev());
#else
	dpsize += sizeof(ROOT);
#endif
	dpsize += sizeof(*ndp);

	start = buf = dp_alloc(dpsize + sizeof(END));

#ifdef CONFIG_DM_ETH
	buf = dp_fill(buf, eth_get_dev());
#else
	memcpy(buf, &ROOT, sizeof(ROOT));
	buf += sizeof(ROOT);
#endif

	ndp = buf;
	ndp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
	ndp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
	ndp->dp.length = sizeof(*ndp);
	memcpy(ndp->mac.addr, eth_get_ethaddr(), ARP_HLEN);
	buf = &ndp[1];

	*((struct efi_device_path *)buf) = END;

	return start;
}
#endif

/* Construct a device-path for memory-mapped image */
struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
					uint64_t start_address,
					uint64_t end_address)
{
	struct efi_device_path_memory *mdp;
	void *buf, *start;

	start = buf = dp_alloc(sizeof(*mdp) + sizeof(END));

	mdp = buf;
	mdp->dp.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
	mdp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MEMORY;
	mdp->dp.length = sizeof(*mdp);
	mdp->memory_type = memory_type;
	mdp->start_address = start_address;
	mdp->end_address = end_address;
	buf = &mdp[1];

	*((struct efi_device_path *)buf) = END;

	return start;
}

/*
 * Helper to split a full device path (containing both device and file
 * parts) into it's constituent parts.
 */
void efi_dp_split_file_path(struct efi_device_path *full_path,
			    struct efi_device_path **device_path,
			    struct efi_device_path **file_path)
{
	struct efi_device_path *p, *dp, *fp;

	dp = efi_dp_dup(full_path);
	p = dp;
	while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH))
		p = efi_dp_next(p);
	fp = efi_dp_dup(p);

	p->type = DEVICE_PATH_TYPE_END;
	p->sub_type = DEVICE_PATH_SUB_TYPE_END;
	p->length = sizeof(*p);

	*device_path = dp;
	*file_path = fp;
}