1 /*
2  * Helper functions used by the EFI stub on multiple
3  * architectures. This should be #included by the EFI stub
4  * implementation files.
5  *
6  * Copyright 2011 Intel Corporation; author Matt Fleming
7  *
8  * This file is part of the Linux kernel, and is made available
9  * under the terms of the GNU General Public License version 2.
10  *
11  */
12 
13 #include <linux/efi.h>
14 #include <asm/efi.h>
15 
16 #include "efistub.h"
17 
18 /*
19  * Some firmware implementations have problems reading files in one go.
20  * A read chunk size of 1MB seems to work for most platforms.
21  *
22  * Unfortunately, reading files in chunks triggers *other* bugs on some
23  * platforms, so we provide a way to disable this workaround, which can
24  * be done by passing "efi=nochunk" on the EFI boot stub command line.
25  *
26  * If you experience issues with initrd images being corrupt it's worth
27  * trying efi=nochunk, but chunking is enabled by default because there
28  * are far more machines that require the workaround than those that
29  * break with it enabled.
30  */
31 #define EFI_READ_CHUNK_SIZE	(1024 * 1024)
32 
33 static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
34 
35 struct file_info {
36 	efi_file_handle_t *handle;
37 	u64 size;
38 };
39 
40 void efi_printk(efi_system_table_t *sys_table_arg, char *str)
41 {
42 	char *s8;
43 
44 	for (s8 = str; *s8; s8++) {
45 		efi_char16_t ch[2] = { 0 };
46 
47 		ch[0] = *s8;
48 		if (*s8 == '\n') {
49 			efi_char16_t nl[2] = { '\r', 0 };
50 			efi_char16_printk(sys_table_arg, nl);
51 		}
52 
53 		efi_char16_printk(sys_table_arg, ch);
54 	}
55 }
56 
57 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
58 				efi_memory_desc_t **map,
59 				unsigned long *map_size,
60 				unsigned long *desc_size,
61 				u32 *desc_ver,
62 				unsigned long *key_ptr)
63 {
64 	efi_memory_desc_t *m = NULL;
65 	efi_status_t status;
66 	unsigned long key;
67 	u32 desc_version;
68 
69 	*map_size = sizeof(*m) * 32;
70 again:
71 	/*
72 	 * Add an additional efi_memory_desc_t because we're doing an
73 	 * allocation which may be in a new descriptor region.
74 	 */
75 	*map_size += sizeof(*m);
76 	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
77 				*map_size, (void **)&m);
78 	if (status != EFI_SUCCESS)
79 		goto fail;
80 
81 	*desc_size = 0;
82 	key = 0;
83 	status = efi_call_early(get_memory_map, map_size, m,
84 				&key, desc_size, &desc_version);
85 	if (status == EFI_BUFFER_TOO_SMALL) {
86 		efi_call_early(free_pool, m);
87 		goto again;
88 	}
89 
90 	if (status != EFI_SUCCESS)
91 		efi_call_early(free_pool, m);
92 
93 	if (key_ptr && status == EFI_SUCCESS)
94 		*key_ptr = key;
95 	if (desc_ver && status == EFI_SUCCESS)
96 		*desc_ver = desc_version;
97 
98 fail:
99 	*map = m;
100 	return status;
101 }
102 
103 
104 unsigned long __init get_dram_base(efi_system_table_t *sys_table_arg)
105 {
106 	efi_status_t status;
107 	unsigned long map_size;
108 	unsigned long membase  = EFI_ERROR;
109 	struct efi_memory_map map;
110 	efi_memory_desc_t *md;
111 
112 	status = efi_get_memory_map(sys_table_arg, (efi_memory_desc_t **)&map.map,
113 				    &map_size, &map.desc_size, NULL, NULL);
114 	if (status != EFI_SUCCESS)
115 		return membase;
116 
117 	map.map_end = map.map + map_size;
118 
119 	for_each_efi_memory_desc(&map, md)
120 		if (md->attribute & EFI_MEMORY_WB)
121 			if (membase > md->phys_addr)
122 				membase = md->phys_addr;
123 
124 	efi_call_early(free_pool, map.map);
125 
126 	return membase;
127 }
128 
129 /*
130  * Allocate at the highest possible address that is not above 'max'.
131  */
132 efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
133 			    unsigned long size, unsigned long align,
134 			    unsigned long *addr, unsigned long max)
135 {
136 	unsigned long map_size, desc_size;
137 	efi_memory_desc_t *map;
138 	efi_status_t status;
139 	unsigned long nr_pages;
140 	u64 max_addr = 0;
141 	int i;
142 
143 	status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
144 				    NULL, NULL);
145 	if (status != EFI_SUCCESS)
146 		goto fail;
147 
148 	/*
149 	 * Enforce minimum alignment that EFI requires when requesting
150 	 * a specific address.  We are doing page-based allocations,
151 	 * so we must be aligned to a page.
152 	 */
153 	if (align < EFI_PAGE_SIZE)
154 		align = EFI_PAGE_SIZE;
155 
156 	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
157 again:
158 	for (i = 0; i < map_size / desc_size; i++) {
159 		efi_memory_desc_t *desc;
160 		unsigned long m = (unsigned long)map;
161 		u64 start, end;
162 
163 		desc = (efi_memory_desc_t *)(m + (i * desc_size));
164 		if (desc->type != EFI_CONVENTIONAL_MEMORY)
165 			continue;
166 
167 		if (desc->num_pages < nr_pages)
168 			continue;
169 
170 		start = desc->phys_addr;
171 		end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
172 
173 		if ((start + size) > end || (start + size) > max)
174 			continue;
175 
176 		if (end - size > max)
177 			end = max;
178 
179 		if (round_down(end - size, align) < start)
180 			continue;
181 
182 		start = round_down(end - size, align);
183 
184 		/*
185 		 * Don't allocate at 0x0. It will confuse code that
186 		 * checks pointers against NULL.
187 		 */
188 		if (start == 0x0)
189 			continue;
190 
191 		if (start > max_addr)
192 			max_addr = start;
193 	}
194 
195 	if (!max_addr)
196 		status = EFI_NOT_FOUND;
197 	else {
198 		status = efi_call_early(allocate_pages,
199 					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
200 					nr_pages, &max_addr);
201 		if (status != EFI_SUCCESS) {
202 			max = max_addr;
203 			max_addr = 0;
204 			goto again;
205 		}
206 
207 		*addr = max_addr;
208 	}
209 
210 	efi_call_early(free_pool, map);
211 fail:
212 	return status;
213 }
214 
215 /*
216  * Allocate at the lowest possible address.
217  */
218 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
219 			   unsigned long size, unsigned long align,
220 			   unsigned long *addr)
221 {
222 	unsigned long map_size, desc_size;
223 	efi_memory_desc_t *map;
224 	efi_status_t status;
225 	unsigned long nr_pages;
226 	int i;
227 
228 	status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
229 				    NULL, NULL);
230 	if (status != EFI_SUCCESS)
231 		goto fail;
232 
233 	/*
234 	 * Enforce minimum alignment that EFI requires when requesting
235 	 * a specific address.  We are doing page-based allocations,
236 	 * so we must be aligned to a page.
237 	 */
238 	if (align < EFI_PAGE_SIZE)
239 		align = EFI_PAGE_SIZE;
240 
241 	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
242 	for (i = 0; i < map_size / desc_size; i++) {
243 		efi_memory_desc_t *desc;
244 		unsigned long m = (unsigned long)map;
245 		u64 start, end;
246 
247 		desc = (efi_memory_desc_t *)(m + (i * desc_size));
248 
249 		if (desc->type != EFI_CONVENTIONAL_MEMORY)
250 			continue;
251 
252 		if (desc->num_pages < nr_pages)
253 			continue;
254 
255 		start = desc->phys_addr;
256 		end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
257 
258 		/*
259 		 * Don't allocate at 0x0. It will confuse code that
260 		 * checks pointers against NULL. Skip the first 8
261 		 * bytes so we start at a nice even number.
262 		 */
263 		if (start == 0x0)
264 			start += 8;
265 
266 		start = round_up(start, align);
267 		if ((start + size) > end)
268 			continue;
269 
270 		status = efi_call_early(allocate_pages,
271 					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
272 					nr_pages, &start);
273 		if (status == EFI_SUCCESS) {
274 			*addr = start;
275 			break;
276 		}
277 	}
278 
279 	if (i == map_size / desc_size)
280 		status = EFI_NOT_FOUND;
281 
282 	efi_call_early(free_pool, map);
283 fail:
284 	return status;
285 }
286 
287 void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
288 	      unsigned long addr)
289 {
290 	unsigned long nr_pages;
291 
292 	if (!size)
293 		return;
294 
295 	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
296 	efi_call_early(free_pages, addr, nr_pages);
297 }
298 
299 /*
300  * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
301  * option, e.g. efi=nochunk.
302  *
303  * It should be noted that efi= is parsed in two very different
304  * environments, first in the early boot environment of the EFI boot
305  * stub, and subsequently during the kernel boot.
306  */
307 efi_status_t efi_parse_options(char *cmdline)
308 {
309 	char *str;
310 
311 	/*
312 	 * If no EFI parameters were specified on the cmdline we've got
313 	 * nothing to do.
314 	 */
315 	str = strstr(cmdline, "efi=");
316 	if (!str)
317 		return EFI_SUCCESS;
318 
319 	/* Skip ahead to first argument */
320 	str += strlen("efi=");
321 
322 	/*
323 	 * Remember, because efi= is also used by the kernel we need to
324 	 * skip over arguments we don't understand.
325 	 */
326 	while (*str) {
327 		if (!strncmp(str, "nochunk", 7)) {
328 			str += strlen("nochunk");
329 			__chunk_size = -1UL;
330 		}
331 
332 		/* Group words together, delimited by "," */
333 		while (*str && *str != ',')
334 			str++;
335 
336 		if (*str == ',')
337 			str++;
338 	}
339 
340 	return EFI_SUCCESS;
341 }
342 
343 /*
344  * Check the cmdline for a LILO-style file= arguments.
345  *
346  * We only support loading a file from the same filesystem as
347  * the kernel image.
348  */
349 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
350 				  efi_loaded_image_t *image,
351 				  char *cmd_line, char *option_string,
352 				  unsigned long max_addr,
353 				  unsigned long *load_addr,
354 				  unsigned long *load_size)
355 {
356 	struct file_info *files;
357 	unsigned long file_addr;
358 	u64 file_size_total;
359 	efi_file_handle_t *fh = NULL;
360 	efi_status_t status;
361 	int nr_files;
362 	char *str;
363 	int i, j, k;
364 
365 	file_addr = 0;
366 	file_size_total = 0;
367 
368 	str = cmd_line;
369 
370 	j = 0;			/* See close_handles */
371 
372 	if (!load_addr || !load_size)
373 		return EFI_INVALID_PARAMETER;
374 
375 	*load_addr = 0;
376 	*load_size = 0;
377 
378 	if (!str || !*str)
379 		return EFI_SUCCESS;
380 
381 	for (nr_files = 0; *str; nr_files++) {
382 		str = strstr(str, option_string);
383 		if (!str)
384 			break;
385 
386 		str += strlen(option_string);
387 
388 		/* Skip any leading slashes */
389 		while (*str == '/' || *str == '\\')
390 			str++;
391 
392 		while (*str && *str != ' ' && *str != '\n')
393 			str++;
394 	}
395 
396 	if (!nr_files)
397 		return EFI_SUCCESS;
398 
399 	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
400 				nr_files * sizeof(*files), (void **)&files);
401 	if (status != EFI_SUCCESS) {
402 		pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
403 		goto fail;
404 	}
405 
406 	str = cmd_line;
407 	for (i = 0; i < nr_files; i++) {
408 		struct file_info *file;
409 		efi_char16_t filename_16[256];
410 		efi_char16_t *p;
411 
412 		str = strstr(str, option_string);
413 		if (!str)
414 			break;
415 
416 		str += strlen(option_string);
417 
418 		file = &files[i];
419 		p = filename_16;
420 
421 		/* Skip any leading slashes */
422 		while (*str == '/' || *str == '\\')
423 			str++;
424 
425 		while (*str && *str != ' ' && *str != '\n') {
426 			if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
427 				break;
428 
429 			if (*str == '/') {
430 				*p++ = '\\';
431 				str++;
432 			} else {
433 				*p++ = *str++;
434 			}
435 		}
436 
437 		*p = '\0';
438 
439 		/* Only open the volume once. */
440 		if (!i) {
441 			status = efi_open_volume(sys_table_arg, image,
442 						 (void **)&fh);
443 			if (status != EFI_SUCCESS)
444 				goto free_files;
445 		}
446 
447 		status = efi_file_size(sys_table_arg, fh, filename_16,
448 				       (void **)&file->handle, &file->size);
449 		if (status != EFI_SUCCESS)
450 			goto close_handles;
451 
452 		file_size_total += file->size;
453 	}
454 
455 	if (file_size_total) {
456 		unsigned long addr;
457 
458 		/*
459 		 * Multiple files need to be at consecutive addresses in memory,
460 		 * so allocate enough memory for all the files.  This is used
461 		 * for loading multiple files.
462 		 */
463 		status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
464 				    &file_addr, max_addr);
465 		if (status != EFI_SUCCESS) {
466 			pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
467 			goto close_handles;
468 		}
469 
470 		/* We've run out of free low memory. */
471 		if (file_addr > max_addr) {
472 			pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
473 			status = EFI_INVALID_PARAMETER;
474 			goto free_file_total;
475 		}
476 
477 		addr = file_addr;
478 		for (j = 0; j < nr_files; j++) {
479 			unsigned long size;
480 
481 			size = files[j].size;
482 			while (size) {
483 				unsigned long chunksize;
484 				if (size > __chunk_size)
485 					chunksize = __chunk_size;
486 				else
487 					chunksize = size;
488 
489 				status = efi_file_read(files[j].handle,
490 						       &chunksize,
491 						       (void *)addr);
492 				if (status != EFI_SUCCESS) {
493 					pr_efi_err(sys_table_arg, "Failed to read file\n");
494 					goto free_file_total;
495 				}
496 				addr += chunksize;
497 				size -= chunksize;
498 			}
499 
500 			efi_file_close(files[j].handle);
501 		}
502 
503 	}
504 
505 	efi_call_early(free_pool, files);
506 
507 	*load_addr = file_addr;
508 	*load_size = file_size_total;
509 
510 	return status;
511 
512 free_file_total:
513 	efi_free(sys_table_arg, file_size_total, file_addr);
514 
515 close_handles:
516 	for (k = j; k < i; k++)
517 		efi_file_close(files[k].handle);
518 free_files:
519 	efi_call_early(free_pool, files);
520 fail:
521 	*load_addr = 0;
522 	*load_size = 0;
523 
524 	return status;
525 }
526 /*
527  * Relocate a kernel image, either compressed or uncompressed.
528  * In the ARM64 case, all kernel images are currently
529  * uncompressed, and as such when we relocate it we need to
530  * allocate additional space for the BSS segment. Any low
531  * memory that this function should avoid needs to be
532  * unavailable in the EFI memory map, as if the preferred
533  * address is not available the lowest available address will
534  * be used.
535  */
536 efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
537 				 unsigned long *image_addr,
538 				 unsigned long image_size,
539 				 unsigned long alloc_size,
540 				 unsigned long preferred_addr,
541 				 unsigned long alignment)
542 {
543 	unsigned long cur_image_addr;
544 	unsigned long new_addr = 0;
545 	efi_status_t status;
546 	unsigned long nr_pages;
547 	efi_physical_addr_t efi_addr = preferred_addr;
548 
549 	if (!image_addr || !image_size || !alloc_size)
550 		return EFI_INVALID_PARAMETER;
551 	if (alloc_size < image_size)
552 		return EFI_INVALID_PARAMETER;
553 
554 	cur_image_addr = *image_addr;
555 
556 	/*
557 	 * The EFI firmware loader could have placed the kernel image
558 	 * anywhere in memory, but the kernel has restrictions on the
559 	 * max physical address it can run at.  Some architectures
560 	 * also have a prefered address, so first try to relocate
561 	 * to the preferred address.  If that fails, allocate as low
562 	 * as possible while respecting the required alignment.
563 	 */
564 	nr_pages = round_up(alloc_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
565 	status = efi_call_early(allocate_pages,
566 				EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
567 				nr_pages, &efi_addr);
568 	new_addr = efi_addr;
569 	/*
570 	 * If preferred address allocation failed allocate as low as
571 	 * possible.
572 	 */
573 	if (status != EFI_SUCCESS) {
574 		status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
575 				       &new_addr);
576 	}
577 	if (status != EFI_SUCCESS) {
578 		pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
579 		return status;
580 	}
581 
582 	/*
583 	 * We know source/dest won't overlap since both memory ranges
584 	 * have been allocated by UEFI, so we can safely use memcpy.
585 	 */
586 	memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
587 
588 	/* Return the new address of the relocated image. */
589 	*image_addr = new_addr;
590 
591 	return status;
592 }
593 
594 /*
595  * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
596  * This overestimates for surrogates, but that is okay.
597  */
598 static int efi_utf8_bytes(u16 c)
599 {
600 	return 1 + (c >= 0x80) + (c >= 0x800);
601 }
602 
603 /*
604  * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
605  */
606 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
607 {
608 	unsigned int c;
609 
610 	while (n--) {
611 		c = *src++;
612 		if (n && c >= 0xd800 && c <= 0xdbff &&
613 		    *src >= 0xdc00 && *src <= 0xdfff) {
614 			c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
615 			src++;
616 			n--;
617 		}
618 		if (c >= 0xd800 && c <= 0xdfff)
619 			c = 0xfffd; /* Unmatched surrogate */
620 		if (c < 0x80) {
621 			*dst++ = c;
622 			continue;
623 		}
624 		if (c < 0x800) {
625 			*dst++ = 0xc0 + (c >> 6);
626 			goto t1;
627 		}
628 		if (c < 0x10000) {
629 			*dst++ = 0xe0 + (c >> 12);
630 			goto t2;
631 		}
632 		*dst++ = 0xf0 + (c >> 18);
633 		*dst++ = 0x80 + ((c >> 12) & 0x3f);
634 	t2:
635 		*dst++ = 0x80 + ((c >> 6) & 0x3f);
636 	t1:
637 		*dst++ = 0x80 + (c & 0x3f);
638 	}
639 
640 	return dst;
641 }
642 
643 /*
644  * Convert the unicode UEFI command line to ASCII to pass to kernel.
645  * Size of memory allocated return in *cmd_line_len.
646  * Returns NULL on error.
647  */
648 char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
649 			  efi_loaded_image_t *image,
650 			  int *cmd_line_len)
651 {
652 	const u16 *s2;
653 	u8 *s1 = NULL;
654 	unsigned long cmdline_addr = 0;
655 	int load_options_chars = image->load_options_size / 2; /* UTF-16 */
656 	const u16 *options = image->load_options;
657 	int options_bytes = 0;  /* UTF-8 bytes */
658 	int options_chars = 0;  /* UTF-16 chars */
659 	efi_status_t status;
660 	u16 zero = 0;
661 
662 	if (options) {
663 		s2 = options;
664 		while (*s2 && *s2 != '\n'
665 		       && options_chars < load_options_chars) {
666 			options_bytes += efi_utf8_bytes(*s2++);
667 			options_chars++;
668 		}
669 	}
670 
671 	if (!options_chars) {
672 		/* No command line options, so return empty string*/
673 		options = &zero;
674 	}
675 
676 	options_bytes++;	/* NUL termination */
677 
678 	status = efi_low_alloc(sys_table_arg, options_bytes, 0, &cmdline_addr);
679 	if (status != EFI_SUCCESS)
680 		return NULL;
681 
682 	s1 = (u8 *)cmdline_addr;
683 	s2 = (const u16 *)options;
684 
685 	s1 = efi_utf16_to_utf8(s1, s2, options_chars);
686 	*s1 = '\0';
687 
688 	*cmd_line_len = options_bytes;
689 	return (char *)cmdline_addr;
690 }
691