summaryrefslogtreecommitdiffstats
path: root/drivers/firmware/efi/libstub/efi-stub-helper.c
blob: 29ed2f9b218ca9892bfcc72da2d91ba4750f4c97 (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
/*
 * Helper functions used by the EFI stub on multiple
 * architectures. This should be #included by the EFI stub
 * implementation files.
 *
 * Copyright 2011 Intel Corporation; author Matt Fleming
 *
 * This file is part of the Linux kernel, and is made available
 * under the terms of the GNU General Public License version 2.
 *
 */

#include <linux/efi.h>
#include <asm/efi.h>

#include "efistub.h"

/*
 * Some firmware implementations have problems reading files in one go.
 * A read chunk size of 1MB seems to work for most platforms.
 *
 * Unfortunately, reading files in chunks triggers *other* bugs on some
 * platforms, so we provide a way to disable this workaround, which can
 * be done by passing "efi=nochunk" on the EFI boot stub command line.
 *
 * If you experience issues with initrd images being corrupt it's worth
 * trying efi=nochunk, but chunking is enabled by default because there
 * are far more machines that require the workaround than those that
 * break with it enabled.
 */
#define EFI_READ_CHUNK_SIZE	(1024 * 1024)

static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;

/*
 * Allow the platform to override the allocation granularity: this allows
 * systems that have the capability to run with a larger page size to deal
 * with the allocations for initrd and fdt more efficiently.
 */
#ifndef EFI_ALLOC_ALIGN
#define EFI_ALLOC_ALIGN		EFI_PAGE_SIZE
#endif

struct file_info {
	efi_file_handle_t *handle;
	u64 size;
};

void efi_printk(efi_system_table_t *sys_table_arg, char *str)
{
	char *s8;

	for (s8 = str; *s8; s8++) {
		efi_char16_t ch[2] = { 0 };

		ch[0] = *s8;
		if (*s8 == '\n') {
			efi_char16_t nl[2] = { '\r', 0 };
			efi_char16_printk(sys_table_arg, nl);
		}

		efi_char16_printk(sys_table_arg, ch);
	}
}

efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
				efi_memory_desc_t **map,
				unsigned long *map_size,
				unsigned long *desc_size,
				u32 *desc_ver,
				unsigned long *key_ptr)
{
	efi_memory_desc_t *m = NULL;
	efi_status_t status;
	unsigned long key;
	u32 desc_version;

	*map_size = sizeof(*m) * 32;
again:
	/*
	 * Add an additional efi_memory_desc_t because we're doing an
	 * allocation which may be in a new descriptor region.
	 */
	*map_size += sizeof(*m);
	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
				*map_size, (void **)&m);
	if (status != EFI_SUCCESS)
		goto fail;

	*desc_size = 0;
	key = 0;
	status = efi_call_early(get_memory_map, map_size, m,
				&key, desc_size, &desc_version);
	if (status == EFI_BUFFER_TOO_SMALL) {
		efi_call_early(free_pool, m);
		goto again;
	}

	if (status != EFI_SUCCESS)
		efi_call_early(free_pool, m);

	if (key_ptr && status == EFI_SUCCESS)
		*key_ptr = key;
	if (desc_ver && status == EFI_SUCCESS)
		*desc_ver = desc_version;

fail:
	*map = m;
	return status;
}


unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
{
	efi_status_t status;
	unsigned long map_size;
	unsigned long membase  = EFI_ERROR;
	struct efi_memory_map map;
	efi_memory_desc_t *md;

	status = efi_get_memory_map(sys_table_arg, (efi_memory_desc_t **)&map.map,
				    &map_size, &map.desc_size, NULL, NULL);
	if (status != EFI_SUCCESS)
		return membase;

	map.map_end = map.map + map_size;

	for_each_efi_memory_desc(&map, md)
		if (md->attribute & EFI_MEMORY_WB)
			if (membase > md->phys_addr)
				membase = md->phys_addr;

	efi_call_early(free_pool, map.map);

	return membase;
}

/*
 * Allocate at the highest possible address that is not above 'max'.
 */
efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
			    unsigned long size, unsigned long align,
			    unsigned long *addr, unsigned long max)
{
	unsigned long map_size, desc_size;
	efi_memory_desc_t *map;
	efi_status_t status;
	unsigned long nr_pages;
	u64 max_addr = 0;
	int i;

	status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
				    NULL, NULL);
	if (status != EFI_SUCCESS)
		goto fail;

	/*
	 * Enforce minimum alignment that EFI requires when requesting
	 * a specific address.  We are doing page-based allocations,
	 * so we must be aligned to a page.
	 */
	if (align < EFI_ALLOC_ALIGN)
		align = EFI_ALLOC_ALIGN;

	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
again:
	for (i = 0; i < map_size / desc_size; i++) {
		efi_memory_desc_t *desc;
		unsigned long m = (unsigned long)map;
		u64 start, end;

		desc = (efi_memory_desc_t *)(m + (i * desc_size));
		if (desc->type != EFI_CONVENTIONAL_MEMORY)
			continue;

		if (desc->num_pages < nr_pages)
			continue;

		start = desc->phys_addr;
		end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);

		if (end > max)
			end = max;

		if ((start + size) > end)
			continue;

		if (round_down(end - size, align) < start)
			continue;

		start = round_down(end - size, align);

		/*
		 * Don't allocate at 0x0. It will confuse code that
		 * checks pointers against NULL.
		 */
		if (start == 0x0)
			continue;

		if (start > max_addr)
			max_addr = start;
	}

	if (!max_addr)
		status = EFI_NOT_FOUND;
	else {
		status = efi_call_early(allocate_pages,
					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
					nr_pages, &max_addr);
		if (status != EFI_SUCCESS) {
			max = max_addr;
			max_addr = 0;
			goto again;
		}

		*addr = max_addr;
	}

	efi_call_early(free_pool, map);
fail:
	return status;
}

/*
 * Allocate at the lowest possible address.
 */
efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
			   unsigned long size, unsigned long align,
			   unsigned long *addr)
{
	unsigned long map_size, desc_size;
	efi_memory_desc_t *map;
	efi_status_t status;
	unsigned long nr_pages;
	int i;

	status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
				    NULL, NULL);
	if (status != EFI_SUCCESS)
		goto fail;

	/*
	 * Enforce minimum alignment that EFI requires when requesting
	 * a specific address.  We are doing page-based allocations,
	 * so we must be aligned to a page.
	 */
	if (align < EFI_ALLOC_ALIGN)
		align = EFI_ALLOC_ALIGN;

	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
	for (i = 0; i < map_size / desc_size; i++) {
		efi_memory_desc_t *desc;
		unsigned long m = (unsigned long)map;
		u64 start, end;

		desc = (efi_memory_desc_t *)(m + (i * desc_size));

		if (desc->type != EFI_CONVENTIONAL_MEMORY)
			continue;

		if (desc->num_pages < nr_pages)
			continue;

		start = desc->phys_addr;
		end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);

		/*
		 * Don't allocate at 0x0. It will confuse code that
		 * checks pointers against NULL. Skip the first 8
		 * bytes so we start at a nice even number.
		 */
		if (start == 0x0)
			start += 8;

		start = round_up(start, align);
		if ((start + size) > end)
			continue;

		status = efi_call_early(allocate_pages,
					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
					nr_pages, &start);
		if (status == EFI_SUCCESS) {
			*addr = start;
			break;
		}
	}

	if (i == map_size / desc_size)
		status = EFI_NOT_FOUND;

	efi_call_early(free_pool, map);
fail:
	return status;
}

void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
	      unsigned long addr)
{
	unsigned long nr_pages;

	if (!size)
		return;

	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
	efi_call_early(free_pages, addr, nr_pages);
}

/*
 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
 * option, e.g. efi=nochunk.
 *
 * It should be noted that efi= is parsed in two very different
 * environments, first in the early boot environment of the EFI boot
 * stub, and subsequently during the kernel boot.
 */
efi_status_t efi_parse_options(char *cmdline)
{
	char *str;

	/*
	 * If no EFI parameters were specified on the cmdline we've got
	 * nothing to do.
	 */
	str = strstr(cmdline, "efi=");
	if (!str)
		return EFI_SUCCESS;

	/* Skip ahead to first argument */
	str += strlen("efi=");

	/*
	 * Remember, because efi= is also used by the kernel we need to
	 * skip over arguments we don't understand.
	 */
	while (*str) {
		if (!strncmp(str, "nochunk", 7)) {
			str += strlen("nochunk");
			__chunk_size = -1UL;
		}

		/* Group words together, delimited by "," */
		while (*str && *str != ',')
			str++;

		if (*str == ',')
			str++;
	}

	return EFI_SUCCESS;
}

/*
 * Check the cmdline for a LILO-style file= arguments.
 *
 * We only support loading a file from the same filesystem as
 * the kernel image.
 */
efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
				  efi_loaded_image_t *image,
				  char *cmd_line, char *option_string,
				  unsigned long max_addr,
				  unsigned long *load_addr,
				  unsigned long *load_size)
{
	struct file_info *files;
	unsigned long file_addr;
	u64 file_size_total;
	efi_file_handle_t *fh = NULL;
	efi_status_t status;
	int nr_files;
	char *str;
	int i, j, k;

	file_addr = 0;
	file_size_total = 0;

	str = cmd_line;

	j = 0;			/* See close_handles */

	if (!load_addr || !load_size)
		return EFI_INVALID_PARAMETER;

	*load_addr = 0;
	*load_size = 0;

	if (!str || !*str)
		return EFI_SUCCESS;

	for (nr_files = 0; *str; nr_files++) {
		str = strstr(str, option_string);
		if (!str)
			break;

		str += strlen(option_string);

		/* Skip any leading slashes */
		while (*str == '/' || *str == '\\')
			str++;

		while (*str && *str != ' ' && *str != '\n')
			str++;
	}

	if (!nr_files)
		return EFI_SUCCESS;

	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
				nr_files * sizeof(*files), (void **)&files);
	if (status != EFI_SUCCESS) {
		pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
		goto fail;
	}

	str = cmd_line;
	for (i = 0; i < nr_files; i++) {
		struct file_info *file;
		efi_char16_t filename_16[256];
		efi_char16_t *p;

		str = strstr(str, option_string);
		if (!str)
			break;

		str += strlen(option_string);

		file = &files[i];
		p = filename_16;

		/* Skip any leading slashes */
		while (*str == '/' || *str == '\\')
			str++;

		while (*str && *str != ' ' && *str != '\n') {
			if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
				break;

			if (*str == '/') {
				*p++ = '\\';
				str++;
			} else {
				*p++ = *str++;
			}
		}

		*p = '\0';

		/* Only open the volume once. */
		if (!i) {
			status = efi_open_volume(sys_table_arg, image,
						 (void **)&fh);
			if (status != EFI_SUCCESS)
				goto free_files;
		}

		status = efi_file_size(sys_table_arg, fh, filename_16,
				       (void **)&file->handle, &file->size);
		if (status != EFI_SUCCESS)
			goto close_handles;

		file_size_total += file->size;
	}

	if (file_size_total) {
		unsigned long addr;

		/*
		 * Multiple files need to be at consecutive addresses in memory,
		 * so allocate enough memory for all the files.  This is used
		 * for loading multiple files.
		 */
		status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
				    &file_addr, max_addr);
		if (status != EFI_SUCCESS) {
			pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
			goto close_handles;
		}

		/* We've run out of free low memory. */
		if (file_addr > max_addr) {
			pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
			status = EFI_INVALID_PARAMETER;
			goto free_file_total;
		}

		addr = file_addr;
		for (j = 0; j < nr_files; j++) {
			unsigned long size;

			size = files[j].size;
			while (size) {
				unsigned long chunksize;
				if (size > __chunk_size)
					chunksize = __chunk_size;
				else
					chunksize = size;

				status = efi_file_read(files[j].handle,
						       &chunksize,
						       (void *)addr);
				if (status != EFI_SUCCESS) {
					pr_efi_err(sys_table_arg, "Failed to read file\n");
					goto free_file_total;
				}
				addr += chunksize;
				size -= chunksize;
			}

			efi_file_close(files[j].handle);
		}

	}

	efi_call_early(free_pool, files);

	*load_addr = file_addr;
	*load_size = file_size_total;

	return status;

free_file_total:
	efi_free(sys_table_arg, file_size_total, file_addr);

close_handles:
	for (k = j; k < i; k++)
		efi_file_close(files[k].handle);
free_files:
	efi_call_early(free_pool, files);
fail:
	*load_addr = 0;
	*load_size = 0;

	return status;
}
/*
 * Relocate a kernel image, either compressed or uncompressed.
 * In the ARM64 case, all kernel images are currently
 * uncompressed, and as such when we relocate it we need to
 * allocate additional space for the BSS segment. Any low
 * memory that this function should avoid needs to be
 * unavailable in the EFI memory map, as if the preferred
 * address is not available the lowest available address will
 * be used.
 */
efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
				 unsigned long *image_addr,
				 unsigned long image_size,
				 unsigned long alloc_size,
				 unsigned long preferred_addr,
				 unsigned long alignment)
{
	unsigned long cur_image_addr;
	unsigned long new_addr = 0;
	efi_status_t status;
	unsigned long nr_pages;
	efi_physical_addr_t efi_addr = preferred_addr;

	if (!image_addr || !image_size || !alloc_size)
		return EFI_INVALID_PARAMETER;
	if (alloc_size < image_size)
		return EFI_INVALID_PARAMETER;

	cur_image_addr = *image_addr;

	/*
	 * The EFI firmware loader could have placed the kernel image
	 * anywhere in memory, but the kernel has restrictions on the
	 * max physical address it can run at.  Some architectures
	 * also have a prefered address, so first try to relocate
	 * to the preferred address.  If that fails, allocate as low
	 * as possible while respecting the required alignment.
	 */
	nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
	status = efi_call_early(allocate_pages,
				EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
				nr_pages, &efi_addr);
	new_addr = efi_addr;
	/*
	 * If preferred address allocation failed allocate as low as
	 * possible.
	 */
	if (status != EFI_SUCCESS) {
		status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
				       &new_addr);
	}
	if (status != EFI_SUCCESS) {
		pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
		return status;
	}

	/*
	 * We know source/dest won't overlap since both memory ranges
	 * have been allocated by UEFI, so we can safely use memcpy.
	 */
	memcpy((void *)new_addr, (void *)cur_image_addr, image_size);

	/* Return the new address of the relocated image. */
	*image_addr = new_addr;

	return status;
}

/*
 * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
 * This overestimates for surrogates, but that is okay.
 */
static int efi_utf8_bytes(u16 c)
{
	return 1 + (c >= 0x80) + (c >= 0x800);
}

/*
 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
 */
static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
{
	unsigned int c;

	while (n--) {
		c = *src++;
		if (n && c >= 0xd800 && c <= 0xdbff &&
		    *src >= 0xdc00 && *src <= 0xdfff) {
			c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
			src++;
			n--;
		}
		if (c >= 0xd800 && c <= 0xdfff)
			c = 0xfffd; /* Unmatched surrogate */
		if (c < 0x80) {
			*dst++ = c;
			continue;
		}
		if (c < 0x800) {
			*dst++ = 0xc0 + (c >> 6);
			goto t1;
		}
		if (c < 0x10000) {
			*dst++ = 0xe0 + (c >> 12);
			goto t2;
		}
		*dst++ = 0xf0 + (c >> 18);
		*dst++ = 0x80 + ((c >> 12) & 0x3f);
	t2:
		*dst++ = 0x80 + ((c >> 6) & 0x3f);
	t1:
		*dst++ = 0x80 + (c & 0x3f);
	}

	return dst;
}

#ifndef MAX_CMDLINE_ADDRESS
#define MAX_CMDLINE_ADDRESS	ULONG_MAX
#endif

/*
 * Convert the unicode UEFI command line to ASCII to pass to kernel.
 * Size of memory allocated return in *cmd_line_len.
 * Returns NULL on error.
 */
char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
			  efi_loaded_image_t *image,
			  int *cmd_line_len)
{
	const u16 *s2;
	u8 *s1 = NULL;
	unsigned long cmdline_addr = 0;
	int load_options_chars = image->load_options_size / 2; /* UTF-16 */
	const u16 *options = image->load_options;
	int options_bytes = 0;  /* UTF-8 bytes */
	int options_chars = 0;  /* UTF-16 chars */
	efi_status_t status;
	u16 zero = 0;

	if (options) {
		s2 = options;
		while (*s2 && *s2 != '\n'
		       && options_chars < load_options_chars) {
			options_bytes += efi_utf8_bytes(*s2++);
			options_chars++;
		}
	}

	if (!options_chars) {
		/* No command line options, so return empty string*/
		options = &zero;
	}

	options_bytes++;	/* NUL termination */

	status = efi_high_alloc(sys_table_arg, options_bytes, 0,
				&cmdline_addr, MAX_CMDLINE_ADDRESS);
	if (status != EFI_SUCCESS)
		return NULL;

	s1 = (u8 *)cmdline_addr;
	s2 = (const u16 *)options;

	s1 = efi_utf16_to_utf8(s1, s2, options_chars);
	*s1 = '\0';

	*cmd_line_len = options_bytes;
	return (char *)cmdline_addr;
}
OpenPOWER on IntegriCloud