2 * Helper functions used by the EFI stub on multiple
3 * architectures. This should be #included by the EFI stub
4 * implementation files.
6 * Copyright 2011 Intel Corporation; author Matt Fleming
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.
13 #include <linux/efi.h>
19 * Some firmware implementations have problems reading files in one go.
20 * A read chunk size of 1MB seems to work for most platforms.
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.
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.
31 #define EFI_READ_CHUNK_SIZE (1024 * 1024)
33 static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
35 static int __section(.data) __nokaslr;
36 static int __section(.data) __quiet;
38 int __pure nokaslr(void)
42 int __pure is_quiet(void)
47 #define EFI_MMAP_NR_SLACK_SLOTS 8
50 efi_file_handle_t *handle;
54 void efi_printk(efi_system_table_t *sys_table_arg, char *str)
58 for (s8 = str; *s8; s8++) {
59 efi_char16_t ch[2] = { 0 };
63 efi_char16_t nl[2] = { '\r', 0 };
64 efi_char16_printk(sys_table_arg, nl);
67 efi_char16_printk(sys_table_arg, ch);
71 static inline bool mmap_has_headroom(unsigned long buff_size,
72 unsigned long map_size,
73 unsigned long desc_size)
75 unsigned long slack = buff_size - map_size;
77 return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
80 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
81 struct efi_boot_memmap *map)
83 efi_memory_desc_t *m = NULL;
88 *map->desc_size = sizeof(*m);
89 *map->map_size = *map->desc_size * 32;
90 *map->buff_size = *map->map_size;
92 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
93 *map->map_size, (void **)&m);
94 if (status != EFI_SUCCESS)
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,
104 efi_call_early(free_pool, m);
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
112 *map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
113 *map->buff_size = *map->map_size;
117 if (status != EFI_SUCCESS)
118 efi_call_early(free_pool, m);
120 if (map->key_ptr && status == EFI_SUCCESS)
122 if (map->desc_ver && status == EFI_SUCCESS)
123 *map->desc_ver = desc_version;
131 unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
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;
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;
147 status = efi_get_memory_map(sys_table_arg, &boot_map);
148 if (status != EFI_SUCCESS)
151 map.map_end = map.map + map_size;
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;
160 efi_call_early(free_pool, map.map);
166 * Allocate at the highest possible address that is not above '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)
172 unsigned long map_size, desc_size, buff_size;
173 efi_memory_desc_t *map;
175 unsigned long nr_pages;
178 struct efi_boot_memmap boot_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;
187 status = efi_get_memory_map(sys_table_arg, &boot_map);
188 if (status != EFI_SUCCESS)
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.
197 if (align < EFI_ALLOC_ALIGN)
198 align = EFI_ALLOC_ALIGN;
200 size = round_up(size, EFI_ALLOC_ALIGN);
201 nr_pages = size / EFI_PAGE_SIZE;
203 for (i = 0; i < map_size / desc_size; i++) {
204 efi_memory_desc_t *desc;
205 unsigned long m = (unsigned long)map;
208 desc = efi_early_memdesc_ptr(m, desc_size, i);
209 if (desc->type != EFI_CONVENTIONAL_MEMORY)
212 if (desc->num_pages < nr_pages)
215 start = desc->phys_addr;
216 end = start + desc->num_pages * EFI_PAGE_SIZE;
221 if ((start + size) > end)
224 if (round_down(end - size, align) < start)
227 start = round_down(end - size, align);
230 * Don't allocate at 0x0. It will confuse code that
231 * checks pointers against NULL.
236 if (start > max_addr)
241 status = EFI_NOT_FOUND;
243 status = efi_call_early(allocate_pages,
244 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
245 nr_pages, &max_addr);
246 if (status != EFI_SUCCESS) {
255 efi_call_early(free_pool, map);
261 * Allocate at the lowest possible address.
263 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
264 unsigned long size, unsigned long align,
267 unsigned long map_size, desc_size, buff_size;
268 efi_memory_desc_t *map;
270 unsigned long nr_pages;
272 struct efi_boot_memmap boot_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;
281 status = efi_get_memory_map(sys_table_arg, &boot_map);
282 if (status != EFI_SUCCESS)
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.
291 if (align < EFI_ALLOC_ALIGN)
292 align = EFI_ALLOC_ALIGN;
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;
301 desc = efi_early_memdesc_ptr(m, desc_size, i);
303 if (desc->type != EFI_CONVENTIONAL_MEMORY)
306 if (desc->num_pages < nr_pages)
309 start = desc->phys_addr;
310 end = start + desc->num_pages * EFI_PAGE_SIZE;
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.
320 start = round_up(start, align);
321 if ((start + size) > end)
324 status = efi_call_early(allocate_pages,
325 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
327 if (status == EFI_SUCCESS) {
333 if (i == map_size / desc_size)
334 status = EFI_NOT_FOUND;
336 efi_call_early(free_pool, map);
341 void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
344 unsigned long nr_pages;
349 nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
350 efi_call_early(free_pages, addr, nr_pages);
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,
357 efi_file_handle_t *h, *fh = __fh;
358 efi_file_info_t *info;
360 efi_guid_t info_guid = EFI_FILE_INFO_ID;
361 unsigned long info_sz;
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");
375 status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
377 if (status != EFI_BUFFER_TOO_SMALL) {
378 efi_printk(sys_table_arg, "Failed to get file info size\n");
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");
390 status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
392 if (status == EFI_BUFFER_TOO_SMALL) {
393 efi_call_early(free_pool, info);
397 *file_sz = info->file_size;
398 efi_call_early(free_pool, info);
400 if (status != EFI_SUCCESS)
401 efi_printk(sys_table_arg, "Failed to get initrd info\n");
406 static efi_status_t efi_file_read(void *handle, unsigned long *size, void *addr)
408 return efi_call_proto(efi_file_handle, read, handle, size, addr);
411 static efi_status_t efi_file_close(void *handle)
413 return efi_call_proto(efi_file_handle, close, handle);
417 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
418 * option, e.g. efi=nochunk.
420 * It should be noted that efi= is parsed in two very different
421 * environments, first in the early boot environment of the EFI boot
422 * stub, and subsequently during the kernel boot.
424 efi_status_t efi_parse_options(char const *cmdline)
428 str = strstr(cmdline, "nokaslr");
429 if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
432 str = strstr(cmdline, "quiet");
433 if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
437 * If no EFI parameters were specified on the cmdline we've got
440 str = strstr(cmdline, "efi=");
444 /* Skip ahead to first argument */
445 str += strlen("efi=");
448 * Remember, because efi= is also used by the kernel we need to
449 * skip over arguments we don't understand.
451 while (*str && *str != ' ') {
452 if (!strncmp(str, "nochunk", 7)) {
453 str += strlen("nochunk");
457 /* Group words together, delimited by "," */
458 while (*str && *str != ' ' && *str != ',')
469 * Check the cmdline for a LILO-style file= arguments.
471 * We only support loading a file from the same filesystem as
474 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
475 efi_loaded_image_t *image,
476 char *cmd_line, char *option_string,
477 unsigned long max_addr,
478 unsigned long *load_addr,
479 unsigned long *load_size)
481 struct file_info *files;
482 unsigned long file_addr;
484 efi_file_handle_t *fh = NULL;
495 j = 0; /* See close_handles */
497 if (!load_addr || !load_size)
498 return EFI_INVALID_PARAMETER;
506 for (nr_files = 0; *str; nr_files++) {
507 str = strstr(str, option_string);
511 str += strlen(option_string);
513 /* Skip any leading slashes */
514 while (*str == '/' || *str == '\\')
517 while (*str && *str != ' ' && *str != '\n')
524 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
525 nr_files * sizeof(*files), (void **)&files);
526 if (status != EFI_SUCCESS) {
527 pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
532 for (i = 0; i < nr_files; i++) {
533 struct file_info *file;
534 efi_char16_t filename_16[256];
537 str = strstr(str, option_string);
541 str += strlen(option_string);
546 /* Skip any leading slashes */
547 while (*str == '/' || *str == '\\')
550 while (*str && *str != ' ' && *str != '\n') {
551 if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
564 /* Only open the volume once. */
566 status = efi_open_volume(sys_table_arg, image,
568 if (status != EFI_SUCCESS)
572 status = efi_file_size(sys_table_arg, fh, filename_16,
573 (void **)&file->handle, &file->size);
574 if (status != EFI_SUCCESS)
577 file_size_total += file->size;
580 if (file_size_total) {
584 * Multiple files need to be at consecutive addresses in memory,
585 * so allocate enough memory for all the files. This is used
586 * for loading multiple files.
588 status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
589 &file_addr, max_addr);
590 if (status != EFI_SUCCESS) {
591 pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
595 /* We've run out of free low memory. */
596 if (file_addr > max_addr) {
597 pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
598 status = EFI_INVALID_PARAMETER;
599 goto free_file_total;
603 for (j = 0; j < nr_files; j++) {
606 size = files[j].size;
608 unsigned long chunksize;
610 if (IS_ENABLED(CONFIG_X86) && size > __chunk_size)
611 chunksize = __chunk_size;
615 status = efi_file_read(files[j].handle,
618 if (status != EFI_SUCCESS) {
619 pr_efi_err(sys_table_arg, "Failed to read file\n");
620 goto free_file_total;
626 efi_file_close(files[j].handle);
631 efi_call_early(free_pool, files);
633 *load_addr = file_addr;
634 *load_size = file_size_total;
639 efi_free(sys_table_arg, file_size_total, file_addr);
642 for (k = j; k < i; k++)
643 efi_file_close(files[k].handle);
645 efi_call_early(free_pool, files);
653 * Relocate a kernel image, either compressed or uncompressed.
654 * In the ARM64 case, all kernel images are currently
655 * uncompressed, and as such when we relocate it we need to
656 * allocate additional space for the BSS segment. Any low
657 * memory that this function should avoid needs to be
658 * unavailable in the EFI memory map, as if the preferred
659 * address is not available the lowest available address will
662 efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
663 unsigned long *image_addr,
664 unsigned long image_size,
665 unsigned long alloc_size,
666 unsigned long preferred_addr,
667 unsigned long alignment)
669 unsigned long cur_image_addr;
670 unsigned long new_addr = 0;
672 unsigned long nr_pages;
673 efi_physical_addr_t efi_addr = preferred_addr;
675 if (!image_addr || !image_size || !alloc_size)
676 return EFI_INVALID_PARAMETER;
677 if (alloc_size < image_size)
678 return EFI_INVALID_PARAMETER;
680 cur_image_addr = *image_addr;
683 * The EFI firmware loader could have placed the kernel image
684 * anywhere in memory, but the kernel has restrictions on the
685 * max physical address it can run at. Some architectures
686 * also have a prefered address, so first try to relocate
687 * to the preferred address. If that fails, allocate as low
688 * as possible while respecting the required alignment.
690 nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
691 status = efi_call_early(allocate_pages,
692 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
693 nr_pages, &efi_addr);
696 * If preferred address allocation failed allocate as low as
699 if (status != EFI_SUCCESS) {
700 status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
703 if (status != EFI_SUCCESS) {
704 pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
709 * We know source/dest won't overlap since both memory ranges
710 * have been allocated by UEFI, so we can safely use memcpy.
712 memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
714 /* Return the new address of the relocated image. */
715 *image_addr = new_addr;
721 * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
722 * This overestimates for surrogates, but that is okay.
724 static int efi_utf8_bytes(u16 c)
726 return 1 + (c >= 0x80) + (c >= 0x800);
730 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
732 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
738 if (n && c >= 0xd800 && c <= 0xdbff &&
739 *src >= 0xdc00 && *src <= 0xdfff) {
740 c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
744 if (c >= 0xd800 && c <= 0xdfff)
745 c = 0xfffd; /* Unmatched surrogate */
751 *dst++ = 0xc0 + (c >> 6);
755 *dst++ = 0xe0 + (c >> 12);
758 *dst++ = 0xf0 + (c >> 18);
759 *dst++ = 0x80 + ((c >> 12) & 0x3f);
761 *dst++ = 0x80 + ((c >> 6) & 0x3f);
763 *dst++ = 0x80 + (c & 0x3f);
769 #ifndef MAX_CMDLINE_ADDRESS
770 #define MAX_CMDLINE_ADDRESS ULONG_MAX
774 * Convert the unicode UEFI command line to ASCII to pass to kernel.
775 * Size of memory allocated return in *cmd_line_len.
776 * Returns NULL on error.
778 char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
779 efi_loaded_image_t *image,
784 unsigned long cmdline_addr = 0;
785 int load_options_chars = image->load_options_size / 2; /* UTF-16 */
786 const u16 *options = image->load_options;
787 int options_bytes = 0; /* UTF-8 bytes */
788 int options_chars = 0; /* UTF-16 chars */
794 while (*s2 && *s2 != '\n'
795 && options_chars < load_options_chars) {
796 options_bytes += efi_utf8_bytes(*s2++);
801 if (!options_chars) {
802 /* No command line options, so return empty string*/
806 options_bytes++; /* NUL termination */
808 status = efi_high_alloc(sys_table_arg, options_bytes, 0,
809 &cmdline_addr, MAX_CMDLINE_ADDRESS);
810 if (status != EFI_SUCCESS)
813 s1 = (u8 *)cmdline_addr;
814 s2 = (const u16 *)options;
816 s1 = efi_utf16_to_utf8(s1, s2, options_chars);
819 *cmd_line_len = options_bytes;
820 return (char *)cmdline_addr;
824 * Handle calling ExitBootServices according to the requirements set out by the
825 * spec. Obtains the current memory map, and returns that info after calling
826 * ExitBootServices. The client must specify a function to perform any
827 * processing of the memory map data prior to ExitBootServices. A client
828 * specific structure may be passed to the function via priv. The client
829 * function may be called multiple times.
831 efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
833 struct efi_boot_memmap *map,
835 efi_exit_boot_map_processing priv_func)
839 status = efi_get_memory_map(sys_table_arg, map);
841 if (status != EFI_SUCCESS)
844 status = priv_func(sys_table_arg, map, priv);
845 if (status != EFI_SUCCESS)
848 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
850 if (status == EFI_INVALID_PARAMETER) {
852 * The memory map changed between efi_get_memory_map() and
853 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4:
854 * EFI_BOOT_SERVICES.ExitBootServices we need to get the
855 * updated map, and try again. The spec implies one retry
856 * should be sufficent, which is confirmed against the EDK2
857 * implementation. Per the spec, we can only invoke
858 * get_memory_map() and exit_boot_services() - we cannot alloc
859 * so efi_get_memory_map() cannot be used, and we must reuse
860 * the buffer. For all practical purposes, the headroom in the
861 * buffer should account for any changes in the map so the call
862 * to get_memory_map() is expected to succeed here.
864 *map->map_size = *map->buff_size;
865 status = efi_call_early(get_memory_map,
872 /* exit_boot_services() was called, thus cannot free */
873 if (status != EFI_SUCCESS)
876 status = priv_func(sys_table_arg, map, priv);
877 /* exit_boot_services() was called, thus cannot free */
878 if (status != EFI_SUCCESS)
881 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
884 /* exit_boot_services() was called, thus cannot free */
885 if (status != EFI_SUCCESS)
891 efi_call_early(free_pool, *map->map);