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 static int __section(.data) __nokaslr;
36 static int __section(.data) __quiet;
37
nokaslr(void)38 int __pure nokaslr(void)
39 {
40 return __nokaslr;
41 }
is_quiet(void)42 int __pure is_quiet(void)
43 {
44 return __quiet;
45 }
46
47 #define EFI_MMAP_NR_SLACK_SLOTS 8
48
49 struct file_info {
50 efi_file_handle_t *handle;
51 u64 size;
52 };
53
efi_printk(efi_system_table_t * sys_table_arg,char * str)54 void efi_printk(efi_system_table_t *sys_table_arg, char *str)
55 {
56 char *s8;
57
58 for (s8 = str; *s8; s8++) {
59 efi_char16_t ch[2] = { 0 };
60
61 ch[0] = *s8;
62 if (*s8 == '\n') {
63 efi_char16_t nl[2] = { '\r', 0 };
64 efi_char16_printk(sys_table_arg, nl);
65 }
66
67 efi_char16_printk(sys_table_arg, ch);
68 }
69 }
70
mmap_has_headroom(unsigned long buff_size,unsigned long map_size,unsigned long desc_size)71 static inline bool mmap_has_headroom(unsigned long buff_size,
72 unsigned long map_size,
73 unsigned long desc_size)
74 {
75 unsigned long slack = buff_size - map_size;
76
77 return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
78 }
79
efi_get_memory_map(efi_system_table_t * sys_table_arg,struct efi_boot_memmap * map)80 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
81 struct efi_boot_memmap *map)
82 {
83 efi_memory_desc_t *m = NULL;
84 efi_status_t status;
85 unsigned long key;
86 u32 desc_version;
87
88 *map->desc_size = sizeof(*m);
89 *map->map_size = *map->desc_size * 32;
90 *map->buff_size = *map->map_size;
91 again:
92 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
93 *map->map_size, (void **)&m);
94 if (status != EFI_SUCCESS)
95 goto fail;
96
97 *map->desc_size = 0;
98 key = 0;
99 status = efi_call_early(get_memory_map, map->map_size, m,
100 &key, map->desc_size, &desc_version);
101 if (status == EFI_BUFFER_TOO_SMALL ||
102 !mmap_has_headroom(*map->buff_size, *map->map_size,
103 *map->desc_size)) {
104 efi_call_early(free_pool, m);
105 /*
106 * Make sure there is some entries of headroom so that the
107 * buffer can be reused for a new map after allocations are
108 * no longer permitted. Its unlikely that the map will grow to
109 * exceed this headroom once we are ready to trigger
110 * ExitBootServices()
111 */
112 *map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
113 *map->buff_size = *map->map_size;
114 goto again;
115 }
116
117 if (status != EFI_SUCCESS)
118 efi_call_early(free_pool, m);
119
120 if (map->key_ptr && status == EFI_SUCCESS)
121 *map->key_ptr = key;
122 if (map->desc_ver && status == EFI_SUCCESS)
123 *map->desc_ver = desc_version;
124
125 fail:
126 *map->map = m;
127 return status;
128 }
129
130
get_dram_base(efi_system_table_t * sys_table_arg)131 unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
132 {
133 efi_status_t status;
134 unsigned long map_size, buff_size;
135 unsigned long membase = EFI_ERROR;
136 struct efi_memory_map map;
137 efi_memory_desc_t *md;
138 struct efi_boot_memmap boot_map;
139
140 boot_map.map = (efi_memory_desc_t **)&map.map;
141 boot_map.map_size = &map_size;
142 boot_map.desc_size = &map.desc_size;
143 boot_map.desc_ver = NULL;
144 boot_map.key_ptr = NULL;
145 boot_map.buff_size = &buff_size;
146
147 status = efi_get_memory_map(sys_table_arg, &boot_map);
148 if (status != EFI_SUCCESS)
149 return membase;
150
151 map.map_end = map.map + map_size;
152
153 for_each_efi_memory_desc_in_map(&map, md) {
154 if (md->attribute & EFI_MEMORY_WB) {
155 if (membase > md->phys_addr)
156 membase = md->phys_addr;
157 }
158 }
159
160 efi_call_early(free_pool, map.map);
161
162 return membase;
163 }
164
165 /*
166 * Allocate at the highest possible address that is not above 'max'.
167 */
efi_high_alloc(efi_system_table_t * sys_table_arg,unsigned long size,unsigned long align,unsigned long * addr,unsigned long max)168 efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
169 unsigned long size, unsigned long align,
170 unsigned long *addr, unsigned long max)
171 {
172 unsigned long map_size, desc_size, buff_size;
173 efi_memory_desc_t *map;
174 efi_status_t status;
175 unsigned long nr_pages;
176 u64 max_addr = 0;
177 int i;
178 struct efi_boot_memmap boot_map;
179
180 boot_map.map = ↦
181 boot_map.map_size = &map_size;
182 boot_map.desc_size = &desc_size;
183 boot_map.desc_ver = NULL;
184 boot_map.key_ptr = NULL;
185 boot_map.buff_size = &buff_size;
186
187 status = efi_get_memory_map(sys_table_arg, &boot_map);
188 if (status != EFI_SUCCESS)
189 goto fail;
190
191 /*
192 * Enforce minimum alignment that EFI or Linux requires when
193 * requesting a specific address. We are doing page-based (or
194 * larger) allocations, and both the address and size must meet
195 * alignment constraints.
196 */
197 if (align < EFI_ALLOC_ALIGN)
198 align = EFI_ALLOC_ALIGN;
199
200 size = round_up(size, EFI_ALLOC_ALIGN);
201 nr_pages = size / EFI_PAGE_SIZE;
202 again:
203 for (i = 0; i < map_size / desc_size; i++) {
204 efi_memory_desc_t *desc;
205 unsigned long m = (unsigned long)map;
206 u64 start, end;
207
208 desc = efi_early_memdesc_ptr(m, desc_size, i);
209 if (desc->type != EFI_CONVENTIONAL_MEMORY)
210 continue;
211
212 if (desc->num_pages < nr_pages)
213 continue;
214
215 start = desc->phys_addr;
216 end = start + desc->num_pages * EFI_PAGE_SIZE;
217
218 if (end > max)
219 end = max;
220
221 if ((start + size) > end)
222 continue;
223
224 if (round_down(end - size, align) < start)
225 continue;
226
227 start = round_down(end - size, align);
228
229 /*
230 * Don't allocate at 0x0. It will confuse code that
231 * checks pointers against NULL.
232 */
233 if (start == 0x0)
234 continue;
235
236 if (start > max_addr)
237 max_addr = start;
238 }
239
240 if (!max_addr)
241 status = EFI_NOT_FOUND;
242 else {
243 status = efi_call_early(allocate_pages,
244 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
245 nr_pages, &max_addr);
246 if (status != EFI_SUCCESS) {
247 max = max_addr;
248 max_addr = 0;
249 goto again;
250 }
251
252 *addr = max_addr;
253 }
254
255 efi_call_early(free_pool, map);
256 fail:
257 return status;
258 }
259
260 /*
261 * Allocate at the lowest possible address.
262 */
efi_low_alloc(efi_system_table_t * sys_table_arg,unsigned long size,unsigned long align,unsigned long * addr)263 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
264 unsigned long size, unsigned long align,
265 unsigned long *addr)
266 {
267 unsigned long map_size, desc_size, buff_size;
268 efi_memory_desc_t *map;
269 efi_status_t status;
270 unsigned long nr_pages;
271 int i;
272 struct efi_boot_memmap boot_map;
273
274 boot_map.map = ↦
275 boot_map.map_size = &map_size;
276 boot_map.desc_size = &desc_size;
277 boot_map.desc_ver = NULL;
278 boot_map.key_ptr = NULL;
279 boot_map.buff_size = &buff_size;
280
281 status = efi_get_memory_map(sys_table_arg, &boot_map);
282 if (status != EFI_SUCCESS)
283 goto fail;
284
285 /*
286 * Enforce minimum alignment that EFI or Linux requires when
287 * requesting a specific address. We are doing page-based (or
288 * larger) allocations, and both the address and size must meet
289 * alignment constraints.
290 */
291 if (align < EFI_ALLOC_ALIGN)
292 align = EFI_ALLOC_ALIGN;
293
294 size = round_up(size, EFI_ALLOC_ALIGN);
295 nr_pages = size / EFI_PAGE_SIZE;
296 for (i = 0; i < map_size / desc_size; i++) {
297 efi_memory_desc_t *desc;
298 unsigned long m = (unsigned long)map;
299 u64 start, end;
300
301 desc = efi_early_memdesc_ptr(m, desc_size, i);
302
303 if (desc->type != EFI_CONVENTIONAL_MEMORY)
304 continue;
305
306 if (desc->num_pages < nr_pages)
307 continue;
308
309 start = desc->phys_addr;
310 end = start + desc->num_pages * EFI_PAGE_SIZE;
311
312 /*
313 * Don't allocate at 0x0. It will confuse code that
314 * checks pointers against NULL. Skip the first 8
315 * bytes so we start at a nice even number.
316 */
317 if (start == 0x0)
318 start += 8;
319
320 start = round_up(start, align);
321 if ((start + size) > end)
322 continue;
323
324 status = efi_call_early(allocate_pages,
325 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
326 nr_pages, &start);
327 if (status == EFI_SUCCESS) {
328 *addr = start;
329 break;
330 }
331 }
332
333 if (i == map_size / desc_size)
334 status = EFI_NOT_FOUND;
335
336 efi_call_early(free_pool, map);
337 fail:
338 return status;
339 }
340
efi_free(efi_system_table_t * sys_table_arg,unsigned long size,unsigned long addr)341 void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
342 unsigned long addr)
343 {
344 unsigned long nr_pages;
345
346 if (!size)
347 return;
348
349 nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
350 efi_call_early(free_pages, addr, nr_pages);
351 }
352
efi_file_size(efi_system_table_t * sys_table_arg,void * __fh,efi_char16_t * filename_16,void ** handle,u64 * file_sz)353 static efi_status_t efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
354 efi_char16_t *filename_16, void **handle,
355 u64 *file_sz)
356 {
357 efi_file_handle_t *h, *fh = __fh;
358 efi_file_info_t *info;
359 efi_status_t status;
360 efi_guid_t info_guid = EFI_FILE_INFO_ID;
361 unsigned long info_sz;
362
363 status = efi_call_proto(efi_file_handle, open, fh, &h, filename_16,
364 EFI_FILE_MODE_READ, (u64)0);
365 if (status != EFI_SUCCESS) {
366 efi_printk(sys_table_arg, "Failed to open file: ");
367 efi_char16_printk(sys_table_arg, filename_16);
368 efi_printk(sys_table_arg, "\n");
369 return status;
370 }
371
372 *handle = h;
373
374 info_sz = 0;
375 status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
376 &info_sz, NULL);
377 if (status != EFI_BUFFER_TOO_SMALL) {
378 efi_printk(sys_table_arg, "Failed to get file info size\n");
379 return status;
380 }
381
382 grow:
383 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
384 info_sz, (void **)&info);
385 if (status != EFI_SUCCESS) {
386 efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
387 return status;
388 }
389
390 status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
391 &info_sz, info);
392 if (status == EFI_BUFFER_TOO_SMALL) {
393 efi_call_early(free_pool, info);
394 goto grow;
395 }
396
397 *file_sz = info->file_size;
398 efi_call_early(free_pool, info);
399
400 if (status != EFI_SUCCESS)
401 efi_printk(sys_table_arg, "Failed to get initrd info\n");
402
403 return status;
404 }
405
efi_file_read(void * handle,unsigned long * size,void * addr)406 static efi_status_t efi_file_read(void *handle, unsigned long *size, void *addr)
407 {
408 return efi_call_proto(efi_file_handle, read, handle, size, addr);
409 }
410
efi_file_close(void * handle)411 static efi_status_t efi_file_close(void *handle)
412 {
413 return efi_call_proto(efi_file_handle, close, handle);
414 }
415
efi_open_volume(efi_system_table_t * sys_table_arg,efi_loaded_image_t * image,efi_file_handle_t ** __fh)416 static efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
417 efi_loaded_image_t *image,
418 efi_file_handle_t **__fh)
419 {
420 efi_file_io_interface_t *io;
421 efi_file_handle_t *fh;
422 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
423 efi_status_t status;
424 void *handle = (void *)(unsigned long)efi_table_attr(efi_loaded_image,
425 device_handle,
426 image);
427
428 status = efi_call_early(handle_protocol, handle,
429 &fs_proto, (void **)&io);
430 if (status != EFI_SUCCESS) {
431 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
432 return status;
433 }
434
435 status = efi_call_proto(efi_file_io_interface, open_volume, io, &fh);
436 if (status != EFI_SUCCESS)
437 efi_printk(sys_table_arg, "Failed to open volume\n");
438 else
439 *__fh = fh;
440
441 return status;
442 }
443
444 /*
445 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
446 * option, e.g. efi=nochunk.
447 *
448 * It should be noted that efi= is parsed in two very different
449 * environments, first in the early boot environment of the EFI boot
450 * stub, and subsequently during the kernel boot.
451 */
efi_parse_options(char const * cmdline)452 efi_status_t efi_parse_options(char const *cmdline)
453 {
454 char *str;
455
456 str = strstr(cmdline, "nokaslr");
457 if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
458 __nokaslr = 1;
459
460 str = strstr(cmdline, "quiet");
461 if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
462 __quiet = 1;
463
464 /*
465 * If no EFI parameters were specified on the cmdline we've got
466 * nothing to do.
467 */
468 str = strstr(cmdline, "efi=");
469 if (!str)
470 return EFI_SUCCESS;
471
472 /* Skip ahead to first argument */
473 str += strlen("efi=");
474
475 /*
476 * Remember, because efi= is also used by the kernel we need to
477 * skip over arguments we don't understand.
478 */
479 while (*str && *str != ' ') {
480 if (!strncmp(str, "nochunk", 7)) {
481 str += strlen("nochunk");
482 __chunk_size = -1UL;
483 }
484
485 /* Group words together, delimited by "," */
486 while (*str && *str != ' ' && *str != ',')
487 str++;
488
489 if (*str == ',')
490 str++;
491 }
492
493 return EFI_SUCCESS;
494 }
495
496 /*
497 * Check the cmdline for a LILO-style file= arguments.
498 *
499 * We only support loading a file from the same filesystem as
500 * the kernel image.
501 */
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)502 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
503 efi_loaded_image_t *image,
504 char *cmd_line, char *option_string,
505 unsigned long max_addr,
506 unsigned long *load_addr,
507 unsigned long *load_size)
508 {
509 struct file_info *files;
510 unsigned long file_addr;
511 u64 file_size_total;
512 efi_file_handle_t *fh = NULL;
513 efi_status_t status;
514 int nr_files;
515 char *str;
516 int i, j, k;
517
518 file_addr = 0;
519 file_size_total = 0;
520
521 str = cmd_line;
522
523 j = 0; /* See close_handles */
524
525 if (!load_addr || !load_size)
526 return EFI_INVALID_PARAMETER;
527
528 *load_addr = 0;
529 *load_size = 0;
530
531 if (!str || !*str)
532 return EFI_SUCCESS;
533
534 for (nr_files = 0; *str; nr_files++) {
535 str = strstr(str, option_string);
536 if (!str)
537 break;
538
539 str += strlen(option_string);
540
541 /* Skip any leading slashes */
542 while (*str == '/' || *str == '\\')
543 str++;
544
545 while (*str && *str != ' ' && *str != '\n')
546 str++;
547 }
548
549 if (!nr_files)
550 return EFI_SUCCESS;
551
552 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
553 nr_files * sizeof(*files), (void **)&files);
554 if (status != EFI_SUCCESS) {
555 pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
556 goto fail;
557 }
558
559 str = cmd_line;
560 for (i = 0; i < nr_files; i++) {
561 struct file_info *file;
562 efi_char16_t filename_16[256];
563 efi_char16_t *p;
564
565 str = strstr(str, option_string);
566 if (!str)
567 break;
568
569 str += strlen(option_string);
570
571 file = &files[i];
572 p = filename_16;
573
574 /* Skip any leading slashes */
575 while (*str == '/' || *str == '\\')
576 str++;
577
578 while (*str && *str != ' ' && *str != '\n') {
579 if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
580 break;
581
582 if (*str == '/') {
583 *p++ = '\\';
584 str++;
585 } else {
586 *p++ = *str++;
587 }
588 }
589
590 *p = '\0';
591
592 /* Only open the volume once. */
593 if (!i) {
594 status = efi_open_volume(sys_table_arg, image, &fh);
595 if (status != EFI_SUCCESS)
596 goto free_files;
597 }
598
599 status = efi_file_size(sys_table_arg, fh, filename_16,
600 (void **)&file->handle, &file->size);
601 if (status != EFI_SUCCESS)
602 goto close_handles;
603
604 file_size_total += file->size;
605 }
606
607 if (file_size_total) {
608 unsigned long addr;
609
610 /*
611 * Multiple files need to be at consecutive addresses in memory,
612 * so allocate enough memory for all the files. This is used
613 * for loading multiple files.
614 */
615 status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
616 &file_addr, max_addr);
617 if (status != EFI_SUCCESS) {
618 pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
619 goto close_handles;
620 }
621
622 /* We've run out of free low memory. */
623 if (file_addr > max_addr) {
624 pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
625 status = EFI_INVALID_PARAMETER;
626 goto free_file_total;
627 }
628
629 addr = file_addr;
630 for (j = 0; j < nr_files; j++) {
631 unsigned long size;
632
633 size = files[j].size;
634 while (size) {
635 unsigned long chunksize;
636
637 if (IS_ENABLED(CONFIG_X86) && size > __chunk_size)
638 chunksize = __chunk_size;
639 else
640 chunksize = size;
641
642 status = efi_file_read(files[j].handle,
643 &chunksize,
644 (void *)addr);
645 if (status != EFI_SUCCESS) {
646 pr_efi_err(sys_table_arg, "Failed to read file\n");
647 goto free_file_total;
648 }
649 addr += chunksize;
650 size -= chunksize;
651 }
652
653 efi_file_close(files[j].handle);
654 }
655
656 }
657
658 efi_call_early(free_pool, files);
659
660 *load_addr = file_addr;
661 *load_size = file_size_total;
662
663 return status;
664
665 free_file_total:
666 efi_free(sys_table_arg, file_size_total, file_addr);
667
668 close_handles:
669 for (k = j; k < i; k++)
670 efi_file_close(files[k].handle);
671 free_files:
672 efi_call_early(free_pool, files);
673 fail:
674 *load_addr = 0;
675 *load_size = 0;
676
677 return status;
678 }
679 /*
680 * Relocate a kernel image, either compressed or uncompressed.
681 * In the ARM64 case, all kernel images are currently
682 * uncompressed, and as such when we relocate it we need to
683 * allocate additional space for the BSS segment. Any low
684 * memory that this function should avoid needs to be
685 * unavailable in the EFI memory map, as if the preferred
686 * address is not available the lowest available address will
687 * be used.
688 */
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)689 efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
690 unsigned long *image_addr,
691 unsigned long image_size,
692 unsigned long alloc_size,
693 unsigned long preferred_addr,
694 unsigned long alignment)
695 {
696 unsigned long cur_image_addr;
697 unsigned long new_addr = 0;
698 efi_status_t status;
699 unsigned long nr_pages;
700 efi_physical_addr_t efi_addr = preferred_addr;
701
702 if (!image_addr || !image_size || !alloc_size)
703 return EFI_INVALID_PARAMETER;
704 if (alloc_size < image_size)
705 return EFI_INVALID_PARAMETER;
706
707 cur_image_addr = *image_addr;
708
709 /*
710 * The EFI firmware loader could have placed the kernel image
711 * anywhere in memory, but the kernel has restrictions on the
712 * max physical address it can run at. Some architectures
713 * also have a prefered address, so first try to relocate
714 * to the preferred address. If that fails, allocate as low
715 * as possible while respecting the required alignment.
716 */
717 nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
718 status = efi_call_early(allocate_pages,
719 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
720 nr_pages, &efi_addr);
721 new_addr = efi_addr;
722 /*
723 * If preferred address allocation failed allocate as low as
724 * possible.
725 */
726 if (status != EFI_SUCCESS) {
727 status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
728 &new_addr);
729 }
730 if (status != EFI_SUCCESS) {
731 pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
732 return status;
733 }
734
735 /*
736 * We know source/dest won't overlap since both memory ranges
737 * have been allocated by UEFI, so we can safely use memcpy.
738 */
739 memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
740
741 /* Return the new address of the relocated image. */
742 *image_addr = new_addr;
743
744 return status;
745 }
746
747 /*
748 * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
749 * This overestimates for surrogates, but that is okay.
750 */
efi_utf8_bytes(u16 c)751 static int efi_utf8_bytes(u16 c)
752 {
753 return 1 + (c >= 0x80) + (c >= 0x800);
754 }
755
756 /*
757 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
758 */
efi_utf16_to_utf8(u8 * dst,const u16 * src,int n)759 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
760 {
761 unsigned int c;
762
763 while (n--) {
764 c = *src++;
765 if (n && c >= 0xd800 && c <= 0xdbff &&
766 *src >= 0xdc00 && *src <= 0xdfff) {
767 c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
768 src++;
769 n--;
770 }
771 if (c >= 0xd800 && c <= 0xdfff)
772 c = 0xfffd; /* Unmatched surrogate */
773 if (c < 0x80) {
774 *dst++ = c;
775 continue;
776 }
777 if (c < 0x800) {
778 *dst++ = 0xc0 + (c >> 6);
779 goto t1;
780 }
781 if (c < 0x10000) {
782 *dst++ = 0xe0 + (c >> 12);
783 goto t2;
784 }
785 *dst++ = 0xf0 + (c >> 18);
786 *dst++ = 0x80 + ((c >> 12) & 0x3f);
787 t2:
788 *dst++ = 0x80 + ((c >> 6) & 0x3f);
789 t1:
790 *dst++ = 0x80 + (c & 0x3f);
791 }
792
793 return dst;
794 }
795
796 #ifndef MAX_CMDLINE_ADDRESS
797 #define MAX_CMDLINE_ADDRESS ULONG_MAX
798 #endif
799
800 /*
801 * Convert the unicode UEFI command line to ASCII to pass to kernel.
802 * Size of memory allocated return in *cmd_line_len.
803 * Returns NULL on error.
804 */
efi_convert_cmdline(efi_system_table_t * sys_table_arg,efi_loaded_image_t * image,int * cmd_line_len)805 char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
806 efi_loaded_image_t *image,
807 int *cmd_line_len)
808 {
809 const u16 *s2;
810 u8 *s1 = NULL;
811 unsigned long cmdline_addr = 0;
812 int load_options_chars = image->load_options_size / 2; /* UTF-16 */
813 const u16 *options = image->load_options;
814 int options_bytes = 0; /* UTF-8 bytes */
815 int options_chars = 0; /* UTF-16 chars */
816 efi_status_t status;
817 u16 zero = 0;
818
819 if (options) {
820 s2 = options;
821 while (*s2 && *s2 != '\n'
822 && options_chars < load_options_chars) {
823 options_bytes += efi_utf8_bytes(*s2++);
824 options_chars++;
825 }
826 }
827
828 if (!options_chars) {
829 /* No command line options, so return empty string*/
830 options = &zero;
831 }
832
833 options_bytes++; /* NUL termination */
834
835 status = efi_high_alloc(sys_table_arg, options_bytes, 0,
836 &cmdline_addr, MAX_CMDLINE_ADDRESS);
837 if (status != EFI_SUCCESS)
838 return NULL;
839
840 s1 = (u8 *)cmdline_addr;
841 s2 = (const u16 *)options;
842
843 s1 = efi_utf16_to_utf8(s1, s2, options_chars);
844 *s1 = '\0';
845
846 *cmd_line_len = options_bytes;
847 return (char *)cmdline_addr;
848 }
849
850 /*
851 * Handle calling ExitBootServices according to the requirements set out by the
852 * spec. Obtains the current memory map, and returns that info after calling
853 * ExitBootServices. The client must specify a function to perform any
854 * processing of the memory map data prior to ExitBootServices. A client
855 * specific structure may be passed to the function via priv. The client
856 * function may be called multiple times.
857 */
efi_exit_boot_services(efi_system_table_t * sys_table_arg,void * handle,struct efi_boot_memmap * map,void * priv,efi_exit_boot_map_processing priv_func)858 efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
859 void *handle,
860 struct efi_boot_memmap *map,
861 void *priv,
862 efi_exit_boot_map_processing priv_func)
863 {
864 efi_status_t status;
865
866 status = efi_get_memory_map(sys_table_arg, map);
867
868 if (status != EFI_SUCCESS)
869 goto fail;
870
871 status = priv_func(sys_table_arg, map, priv);
872 if (status != EFI_SUCCESS)
873 goto free_map;
874
875 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
876
877 if (status == EFI_INVALID_PARAMETER) {
878 /*
879 * The memory map changed between efi_get_memory_map() and
880 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4:
881 * EFI_BOOT_SERVICES.ExitBootServices we need to get the
882 * updated map, and try again. The spec implies one retry
883 * should be sufficent, which is confirmed against the EDK2
884 * implementation. Per the spec, we can only invoke
885 * get_memory_map() and exit_boot_services() - we cannot alloc
886 * so efi_get_memory_map() cannot be used, and we must reuse
887 * the buffer. For all practical purposes, the headroom in the
888 * buffer should account for any changes in the map so the call
889 * to get_memory_map() is expected to succeed here.
890 */
891 *map->map_size = *map->buff_size;
892 status = efi_call_early(get_memory_map,
893 map->map_size,
894 *map->map,
895 map->key_ptr,
896 map->desc_size,
897 map->desc_ver);
898
899 /* exit_boot_services() was called, thus cannot free */
900 if (status != EFI_SUCCESS)
901 goto fail;
902
903 status = priv_func(sys_table_arg, map, priv);
904 /* exit_boot_services() was called, thus cannot free */
905 if (status != EFI_SUCCESS)
906 goto fail;
907
908 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
909 }
910
911 /* exit_boot_services() was called, thus cannot free */
912 if (status != EFI_SUCCESS)
913 goto fail;
914
915 return EFI_SUCCESS;
916
917 free_map:
918 efi_call_early(free_pool, *map->map);
919 fail:
920 return status;
921 }
922
