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 #define EFI_MMAP_NR_SLACK_SLOTS 8
38 efi_file_handle_t *handle;
42 void efi_printk(efi_system_table_t *sys_table_arg, char *str)
46 for (s8 = str; *s8; s8++) {
47 efi_char16_t ch[2] = { 0 };
51 efi_char16_t nl[2] = { '\r', 0 };
52 efi_char16_printk(sys_table_arg, nl);
55 efi_char16_printk(sys_table_arg, ch);
59 static inline bool mmap_has_headroom(unsigned long buff_size,
60 unsigned long map_size,
61 unsigned long desc_size)
63 unsigned long slack = buff_size - map_size;
65 return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
68 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
69 struct efi_boot_memmap *map)
71 efi_memory_desc_t *m = NULL;
76 *map->desc_size = sizeof(*m);
77 *map->map_size = *map->desc_size * 32;
78 *map->buff_size = *map->map_size;
80 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
81 *map->map_size, (void **)&m);
82 if (status != EFI_SUCCESS)
87 status = efi_call_early(get_memory_map, map->map_size, m,
88 &key, map->desc_size, &desc_version);
89 if (status == EFI_BUFFER_TOO_SMALL ||
90 !mmap_has_headroom(*map->buff_size, *map->map_size,
92 efi_call_early(free_pool, m);
94 * Make sure there is some entries of headroom so that the
95 * buffer can be reused for a new map after allocations are
96 * no longer permitted. Its unlikely that the map will grow to
97 * exceed this headroom once we are ready to trigger
100 *map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
101 *map->buff_size = *map->map_size;
105 if (status != EFI_SUCCESS)
106 efi_call_early(free_pool, m);
108 if (map->key_ptr && status == EFI_SUCCESS)
110 if (map->desc_ver && status == EFI_SUCCESS)
111 *map->desc_ver = desc_version;
119 unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
122 unsigned long map_size, buff_size;
123 unsigned long membase = EFI_ERROR;
124 struct efi_memory_map map;
125 efi_memory_desc_t *md;
126 struct efi_boot_memmap boot_map;
128 boot_map.map = (efi_memory_desc_t **)&map.map;
129 boot_map.map_size = &map_size;
130 boot_map.desc_size = &map.desc_size;
131 boot_map.desc_ver = NULL;
132 boot_map.key_ptr = NULL;
133 boot_map.buff_size = &buff_size;
135 status = efi_get_memory_map(sys_table_arg, &boot_map);
136 if (status != EFI_SUCCESS)
139 map.map_end = map.map + map_size;
141 for_each_efi_memory_desc_in_map(&map, md) {
142 if (md->attribute & EFI_MEMORY_WB) {
143 if (membase > md->phys_addr)
144 membase = md->phys_addr;
148 efi_call_early(free_pool, map.map);
154 * Allocate at the highest possible address that is not above 'max'.
156 efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
157 unsigned long size, unsigned long align,
158 unsigned long *addr, unsigned long max)
160 unsigned long map_size, desc_size, buff_size;
161 efi_memory_desc_t *map;
163 unsigned long nr_pages;
166 struct efi_boot_memmap boot_map;
169 boot_map.map_size = &map_size;
170 boot_map.desc_size = &desc_size;
171 boot_map.desc_ver = NULL;
172 boot_map.key_ptr = NULL;
173 boot_map.buff_size = &buff_size;
175 status = efi_get_memory_map(sys_table_arg, &boot_map);
176 if (status != EFI_SUCCESS)
180 * Enforce minimum alignment that EFI or Linux requires when
181 * requesting a specific address. We are doing page-based (or
182 * larger) allocations, and both the address and size must meet
183 * alignment constraints.
185 if (align < EFI_ALLOC_ALIGN)
186 align = EFI_ALLOC_ALIGN;
188 size = round_up(size, EFI_ALLOC_ALIGN);
189 nr_pages = size / EFI_PAGE_SIZE;
191 for (i = 0; i < map_size / desc_size; i++) {
192 efi_memory_desc_t *desc;
193 unsigned long m = (unsigned long)map;
196 desc = (efi_memory_desc_t *)(m + (i * desc_size));
197 if (desc->type != EFI_CONVENTIONAL_MEMORY)
200 if (desc->num_pages < nr_pages)
203 start = desc->phys_addr;
204 end = start + desc->num_pages * EFI_PAGE_SIZE;
209 if ((start + size) > end)
212 if (round_down(end - size, align) < start)
215 start = round_down(end - size, align);
218 * Don't allocate at 0x0. It will confuse code that
219 * checks pointers against NULL.
224 if (start > max_addr)
229 status = EFI_NOT_FOUND;
231 status = efi_call_early(allocate_pages,
232 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
233 nr_pages, &max_addr);
234 if (status != EFI_SUCCESS) {
243 efi_call_early(free_pool, map);
249 * Allocate at the lowest possible address.
251 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
252 unsigned long size, unsigned long align,
255 unsigned long map_size, desc_size, buff_size;
256 efi_memory_desc_t *map;
258 unsigned long nr_pages;
260 struct efi_boot_memmap boot_map;
263 boot_map.map_size = &map_size;
264 boot_map.desc_size = &desc_size;
265 boot_map.desc_ver = NULL;
266 boot_map.key_ptr = NULL;
267 boot_map.buff_size = &buff_size;
269 status = efi_get_memory_map(sys_table_arg, &boot_map);
270 if (status != EFI_SUCCESS)
274 * Enforce minimum alignment that EFI or Linux requires when
275 * requesting a specific address. We are doing page-based (or
276 * larger) allocations, and both the address and size must meet
277 * alignment constraints.
279 if (align < EFI_ALLOC_ALIGN)
280 align = EFI_ALLOC_ALIGN;
282 size = round_up(size, EFI_ALLOC_ALIGN);
283 nr_pages = size / EFI_PAGE_SIZE;
284 for (i = 0; i < map_size / desc_size; i++) {
285 efi_memory_desc_t *desc;
286 unsigned long m = (unsigned long)map;
289 desc = (efi_memory_desc_t *)(m + (i * desc_size));
291 if (desc->type != EFI_CONVENTIONAL_MEMORY)
294 if (desc->num_pages < nr_pages)
297 start = desc->phys_addr;
298 end = start + desc->num_pages * EFI_PAGE_SIZE;
301 * Don't allocate at 0x0. It will confuse code that
302 * checks pointers against NULL. Skip the first 8
303 * bytes so we start at a nice even number.
308 start = round_up(start, align);
309 if ((start + size) > end)
312 status = efi_call_early(allocate_pages,
313 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
315 if (status == EFI_SUCCESS) {
321 if (i == map_size / desc_size)
322 status = EFI_NOT_FOUND;
324 efi_call_early(free_pool, map);
329 void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
332 unsigned long nr_pages;
337 nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
338 efi_call_early(free_pages, addr, nr_pages);
341 static efi_status_t efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
342 efi_char16_t *filename_16, void **handle,
345 efi_file_handle_t *h, *fh = __fh;
346 efi_file_info_t *info;
348 efi_guid_t info_guid = EFI_FILE_INFO_ID;
349 unsigned long info_sz;
351 status = efi_call_proto(efi_file_handle, open, fh, &h, filename_16,
352 EFI_FILE_MODE_READ, (u64)0);
353 if (status != EFI_SUCCESS) {
354 efi_printk(sys_table_arg, "Failed to open file: ");
355 efi_char16_printk(sys_table_arg, filename_16);
356 efi_printk(sys_table_arg, "\n");
363 status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
365 if (status != EFI_BUFFER_TOO_SMALL) {
366 efi_printk(sys_table_arg, "Failed to get file info size\n");
371 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
372 info_sz, (void **)&info);
373 if (status != EFI_SUCCESS) {
374 efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
378 status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
380 if (status == EFI_BUFFER_TOO_SMALL) {
381 efi_call_early(free_pool, info);
385 *file_sz = info->file_size;
386 efi_call_early(free_pool, info);
388 if (status != EFI_SUCCESS)
389 efi_printk(sys_table_arg, "Failed to get initrd info\n");
394 static efi_status_t efi_file_read(void *handle, unsigned long *size, void *addr)
396 return efi_call_proto(efi_file_handle, read, handle, size, addr);
399 static efi_status_t efi_file_close(void *handle)
401 return efi_call_proto(efi_file_handle, close, handle);
405 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
406 * option, e.g. efi=nochunk.
408 * It should be noted that efi= is parsed in two very different
409 * environments, first in the early boot environment of the EFI boot
410 * stub, and subsequently during the kernel boot.
412 efi_status_t efi_parse_options(char *cmdline)
417 * Currently, the only efi= option we look for is 'nochunk', which
418 * is intended to work around known issues on certain x86 UEFI
419 * versions. So ignore for now on other architectures.
421 if (!IS_ENABLED(CONFIG_X86))
425 * If no EFI parameters were specified on the cmdline we've got
428 str = strstr(cmdline, "efi=");
432 /* Skip ahead to first argument */
433 str += strlen("efi=");
436 * Remember, because efi= is also used by the kernel we need to
437 * skip over arguments we don't understand.
440 if (!strncmp(str, "nochunk", 7)) {
441 str += strlen("nochunk");
445 /* Group words together, delimited by "," */
446 while (*str && *str != ',')
457 * Check the cmdline for a LILO-style file= arguments.
459 * We only support loading a file from the same filesystem as
462 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
463 efi_loaded_image_t *image,
464 char *cmd_line, char *option_string,
465 unsigned long max_addr,
466 unsigned long *load_addr,
467 unsigned long *load_size)
469 struct file_info *files;
470 unsigned long file_addr;
472 efi_file_handle_t *fh = NULL;
483 j = 0; /* See close_handles */
485 if (!load_addr || !load_size)
486 return EFI_INVALID_PARAMETER;
494 for (nr_files = 0; *str; nr_files++) {
495 str = strstr(str, option_string);
499 str += strlen(option_string);
501 /* Skip any leading slashes */
502 while (*str == '/' || *str == '\\')
505 while (*str && *str != ' ' && *str != '\n')
512 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
513 nr_files * sizeof(*files), (void **)&files);
514 if (status != EFI_SUCCESS) {
515 pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
520 for (i = 0; i < nr_files; i++) {
521 struct file_info *file;
522 efi_char16_t filename_16[256];
525 str = strstr(str, option_string);
529 str += strlen(option_string);
534 /* Skip any leading slashes */
535 while (*str == '/' || *str == '\\')
538 while (*str && *str != ' ' && *str != '\n') {
539 if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
552 /* Only open the volume once. */
554 status = efi_open_volume(sys_table_arg, image,
556 if (status != EFI_SUCCESS)
560 status = efi_file_size(sys_table_arg, fh, filename_16,
561 (void **)&file->handle, &file->size);
562 if (status != EFI_SUCCESS)
565 file_size_total += file->size;
568 if (file_size_total) {
572 * Multiple files need to be at consecutive addresses in memory,
573 * so allocate enough memory for all the files. This is used
574 * for loading multiple files.
576 status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
577 &file_addr, max_addr);
578 if (status != EFI_SUCCESS) {
579 pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
583 /* We've run out of free low memory. */
584 if (file_addr > max_addr) {
585 pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
586 status = EFI_INVALID_PARAMETER;
587 goto free_file_total;
591 for (j = 0; j < nr_files; j++) {
594 size = files[j].size;
596 unsigned long chunksize;
598 if (IS_ENABLED(CONFIG_X86) && size > __chunk_size)
599 chunksize = __chunk_size;
603 status = efi_file_read(files[j].handle,
606 if (status != EFI_SUCCESS) {
607 pr_efi_err(sys_table_arg, "Failed to read file\n");
608 goto free_file_total;
614 efi_file_close(files[j].handle);
619 efi_call_early(free_pool, files);
621 *load_addr = file_addr;
622 *load_size = file_size_total;
627 efi_free(sys_table_arg, file_size_total, file_addr);
630 for (k = j; k < i; k++)
631 efi_file_close(files[k].handle);
633 efi_call_early(free_pool, files);
641 * Relocate a kernel image, either compressed or uncompressed.
642 * In the ARM64 case, all kernel images are currently
643 * uncompressed, and as such when we relocate it we need to
644 * allocate additional space for the BSS segment. Any low
645 * memory that this function should avoid needs to be
646 * unavailable in the EFI memory map, as if the preferred
647 * address is not available the lowest available address will
650 efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
651 unsigned long *image_addr,
652 unsigned long image_size,
653 unsigned long alloc_size,
654 unsigned long preferred_addr,
655 unsigned long alignment)
657 unsigned long cur_image_addr;
658 unsigned long new_addr = 0;
660 unsigned long nr_pages;
661 efi_physical_addr_t efi_addr = preferred_addr;
663 if (!image_addr || !image_size || !alloc_size)
664 return EFI_INVALID_PARAMETER;
665 if (alloc_size < image_size)
666 return EFI_INVALID_PARAMETER;
668 cur_image_addr = *image_addr;
671 * The EFI firmware loader could have placed the kernel image
672 * anywhere in memory, but the kernel has restrictions on the
673 * max physical address it can run at. Some architectures
674 * also have a prefered address, so first try to relocate
675 * to the preferred address. If that fails, allocate as low
676 * as possible while respecting the required alignment.
678 nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
679 status = efi_call_early(allocate_pages,
680 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
681 nr_pages, &efi_addr);
684 * If preferred address allocation failed allocate as low as
687 if (status != EFI_SUCCESS) {
688 status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
691 if (status != EFI_SUCCESS) {
692 pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
697 * We know source/dest won't overlap since both memory ranges
698 * have been allocated by UEFI, so we can safely use memcpy.
700 memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
702 /* Return the new address of the relocated image. */
703 *image_addr = new_addr;
709 * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
710 * This overestimates for surrogates, but that is okay.
712 static int efi_utf8_bytes(u16 c)
714 return 1 + (c >= 0x80) + (c >= 0x800);
718 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
720 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
726 if (n && c >= 0xd800 && c <= 0xdbff &&
727 *src >= 0xdc00 && *src <= 0xdfff) {
728 c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
732 if (c >= 0xd800 && c <= 0xdfff)
733 c = 0xfffd; /* Unmatched surrogate */
739 *dst++ = 0xc0 + (c >> 6);
743 *dst++ = 0xe0 + (c >> 12);
746 *dst++ = 0xf0 + (c >> 18);
747 *dst++ = 0x80 + ((c >> 12) & 0x3f);
749 *dst++ = 0x80 + ((c >> 6) & 0x3f);
751 *dst++ = 0x80 + (c & 0x3f);
757 #ifndef MAX_CMDLINE_ADDRESS
758 #define MAX_CMDLINE_ADDRESS ULONG_MAX
762 * Convert the unicode UEFI command line to ASCII to pass to kernel.
763 * Size of memory allocated return in *cmd_line_len.
764 * Returns NULL on error.
766 char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
767 efi_loaded_image_t *image,
772 unsigned long cmdline_addr = 0;
773 int load_options_chars = image->load_options_size / 2; /* UTF-16 */
774 const u16 *options = image->load_options;
775 int options_bytes = 0; /* UTF-8 bytes */
776 int options_chars = 0; /* UTF-16 chars */
782 while (*s2 && *s2 != '\n'
783 && options_chars < load_options_chars) {
784 options_bytes += efi_utf8_bytes(*s2++);
789 if (!options_chars) {
790 /* No command line options, so return empty string*/
794 options_bytes++; /* NUL termination */
796 status = efi_high_alloc(sys_table_arg, options_bytes, 0,
797 &cmdline_addr, MAX_CMDLINE_ADDRESS);
798 if (status != EFI_SUCCESS)
801 s1 = (u8 *)cmdline_addr;
802 s2 = (const u16 *)options;
804 s1 = efi_utf16_to_utf8(s1, s2, options_chars);
807 *cmd_line_len = options_bytes;
808 return (char *)cmdline_addr;
812 * Handle calling ExitBootServices according to the requirements set out by the
813 * spec. Obtains the current memory map, and returns that info after calling
814 * ExitBootServices. The client must specify a function to perform any
815 * processing of the memory map data prior to ExitBootServices. A client
816 * specific structure may be passed to the function via priv. The client
817 * function may be called multiple times.
819 efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
821 struct efi_boot_memmap *map,
823 efi_exit_boot_map_processing priv_func)
827 status = efi_get_memory_map(sys_table_arg, map);
829 if (status != EFI_SUCCESS)
832 status = priv_func(sys_table_arg, map, priv);
833 if (status != EFI_SUCCESS)
836 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
838 if (status == EFI_INVALID_PARAMETER) {
840 * The memory map changed between efi_get_memory_map() and
841 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4:
842 * EFI_BOOT_SERVICES.ExitBootServices we need to get the
843 * updated map, and try again. The spec implies one retry
844 * should be sufficent, which is confirmed against the EDK2
845 * implementation. Per the spec, we can only invoke
846 * get_memory_map() and exit_boot_services() - we cannot alloc
847 * so efi_get_memory_map() cannot be used, and we must reuse
848 * the buffer. For all practical purposes, the headroom in the
849 * buffer should account for any changes in the map so the call
850 * to get_memory_map() is expected to succeed here.
852 *map->map_size = *map->buff_size;
853 status = efi_call_early(get_memory_map,
860 /* exit_boot_services() was called, thus cannot free */
861 if (status != EFI_SUCCESS)
864 status = priv_func(sys_table_arg, map, priv);
865 /* exit_boot_services() was called, thus cannot free */
866 if (status != EFI_SUCCESS)
869 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
872 /* exit_boot_services() was called, thus cannot free */
873 if (status != EFI_SUCCESS)
879 efi_call_early(free_pool, *map->map);