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;
37 int __pure nokaslr(void)
42 #define EFI_MMAP_NR_SLACK_SLOTS 8
45 efi_file_handle_t *handle;
49 void efi_printk(efi_system_table_t *sys_table_arg, char *str)
53 for (s8 = str; *s8; s8++) {
54 efi_char16_t ch[2] = { 0 };
58 efi_char16_t nl[2] = { '\r', 0 };
59 efi_char16_printk(sys_table_arg, nl);
62 efi_char16_printk(sys_table_arg, ch);
66 static inline bool mmap_has_headroom(unsigned long buff_size,
67 unsigned long map_size,
68 unsigned long desc_size)
70 unsigned long slack = buff_size - map_size;
72 return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
75 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
76 struct efi_boot_memmap *map)
78 efi_memory_desc_t *m = NULL;
83 *map->desc_size = sizeof(*m);
84 *map->map_size = *map->desc_size * 32;
85 *map->buff_size = *map->map_size;
87 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
88 *map->map_size, (void **)&m);
89 if (status != EFI_SUCCESS)
94 status = efi_call_early(get_memory_map, map->map_size, m,
95 &key, map->desc_size, &desc_version);
96 if (status == EFI_BUFFER_TOO_SMALL ||
97 !mmap_has_headroom(*map->buff_size, *map->map_size,
99 efi_call_early(free_pool, m);
101 * Make sure there is some entries of headroom so that the
102 * buffer can be reused for a new map after allocations are
103 * no longer permitted. Its unlikely that the map will grow to
104 * exceed this headroom once we are ready to trigger
107 *map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
108 *map->buff_size = *map->map_size;
112 if (status != EFI_SUCCESS)
113 efi_call_early(free_pool, m);
115 if (map->key_ptr && status == EFI_SUCCESS)
117 if (map->desc_ver && status == EFI_SUCCESS)
118 *map->desc_ver = desc_version;
126 unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
129 unsigned long map_size, buff_size;
130 unsigned long membase = EFI_ERROR;
131 struct efi_memory_map map;
132 efi_memory_desc_t *md;
133 struct efi_boot_memmap boot_map;
135 boot_map.map = (efi_memory_desc_t **)&map.map;
136 boot_map.map_size = &map_size;
137 boot_map.desc_size = &map.desc_size;
138 boot_map.desc_ver = NULL;
139 boot_map.key_ptr = NULL;
140 boot_map.buff_size = &buff_size;
142 status = efi_get_memory_map(sys_table_arg, &boot_map);
143 if (status != EFI_SUCCESS)
146 map.map_end = map.map + map_size;
148 for_each_efi_memory_desc_in_map(&map, md) {
149 if (md->attribute & EFI_MEMORY_WB) {
150 if (membase > md->phys_addr)
151 membase = md->phys_addr;
155 efi_call_early(free_pool, map.map);
161 * Allocate at the highest possible address that is not above 'max'.
163 efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
164 unsigned long size, unsigned long align,
165 unsigned long *addr, unsigned long max)
167 unsigned long map_size, desc_size, buff_size;
168 efi_memory_desc_t *map;
170 unsigned long nr_pages;
173 struct efi_boot_memmap boot_map;
176 boot_map.map_size = &map_size;
177 boot_map.desc_size = &desc_size;
178 boot_map.desc_ver = NULL;
179 boot_map.key_ptr = NULL;
180 boot_map.buff_size = &buff_size;
182 status = efi_get_memory_map(sys_table_arg, &boot_map);
183 if (status != EFI_SUCCESS)
187 * Enforce minimum alignment that EFI or Linux requires when
188 * requesting a specific address. We are doing page-based (or
189 * larger) allocations, and both the address and size must meet
190 * alignment constraints.
192 if (align < EFI_ALLOC_ALIGN)
193 align = EFI_ALLOC_ALIGN;
195 size = round_up(size, EFI_ALLOC_ALIGN);
196 nr_pages = size / EFI_PAGE_SIZE;
198 for (i = 0; i < map_size / desc_size; i++) {
199 efi_memory_desc_t *desc;
200 unsigned long m = (unsigned long)map;
203 desc = (efi_memory_desc_t *)(m + (i * desc_size));
204 if (desc->type != EFI_CONVENTIONAL_MEMORY)
207 if (desc->num_pages < nr_pages)
210 start = desc->phys_addr;
211 end = start + desc->num_pages * EFI_PAGE_SIZE;
216 if ((start + size) > end)
219 if (round_down(end - size, align) < start)
222 start = round_down(end - size, align);
225 * Don't allocate at 0x0. It will confuse code that
226 * checks pointers against NULL.
231 if (start > max_addr)
236 status = EFI_NOT_FOUND;
238 status = efi_call_early(allocate_pages,
239 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
240 nr_pages, &max_addr);
241 if (status != EFI_SUCCESS) {
250 efi_call_early(free_pool, map);
256 * Allocate at the lowest possible address.
258 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
259 unsigned long size, unsigned long align,
262 unsigned long map_size, desc_size, buff_size;
263 efi_memory_desc_t *map;
265 unsigned long nr_pages;
267 struct efi_boot_memmap boot_map;
270 boot_map.map_size = &map_size;
271 boot_map.desc_size = &desc_size;
272 boot_map.desc_ver = NULL;
273 boot_map.key_ptr = NULL;
274 boot_map.buff_size = &buff_size;
276 status = efi_get_memory_map(sys_table_arg, &boot_map);
277 if (status != EFI_SUCCESS)
281 * Enforce minimum alignment that EFI or Linux requires when
282 * requesting a specific address. We are doing page-based (or
283 * larger) allocations, and both the address and size must meet
284 * alignment constraints.
286 if (align < EFI_ALLOC_ALIGN)
287 align = EFI_ALLOC_ALIGN;
289 size = round_up(size, EFI_ALLOC_ALIGN);
290 nr_pages = size / EFI_PAGE_SIZE;
291 for (i = 0; i < map_size / desc_size; i++) {
292 efi_memory_desc_t *desc;
293 unsigned long m = (unsigned long)map;
296 desc = (efi_memory_desc_t *)(m + (i * desc_size));
298 if (desc->type != EFI_CONVENTIONAL_MEMORY)
301 if (desc->num_pages < nr_pages)
304 start = desc->phys_addr;
305 end = start + desc->num_pages * EFI_PAGE_SIZE;
308 * Don't allocate at 0x0. It will confuse code that
309 * checks pointers against NULL. Skip the first 8
310 * bytes so we start at a nice even number.
315 start = round_up(start, align);
316 if ((start + size) > end)
319 status = efi_call_early(allocate_pages,
320 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
322 if (status == EFI_SUCCESS) {
328 if (i == map_size / desc_size)
329 status = EFI_NOT_FOUND;
331 efi_call_early(free_pool, map);
336 void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
339 unsigned long nr_pages;
344 nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
345 efi_call_early(free_pages, addr, nr_pages);
348 static efi_status_t efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
349 efi_char16_t *filename_16, void **handle,
352 efi_file_handle_t *h, *fh = __fh;
353 efi_file_info_t *info;
355 efi_guid_t info_guid = EFI_FILE_INFO_ID;
356 unsigned long info_sz;
358 status = efi_call_proto(efi_file_handle, open, fh, &h, filename_16,
359 EFI_FILE_MODE_READ, (u64)0);
360 if (status != EFI_SUCCESS) {
361 efi_printk(sys_table_arg, "Failed to open file: ");
362 efi_char16_printk(sys_table_arg, filename_16);
363 efi_printk(sys_table_arg, "\n");
370 status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
372 if (status != EFI_BUFFER_TOO_SMALL) {
373 efi_printk(sys_table_arg, "Failed to get file info size\n");
378 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
379 info_sz, (void **)&info);
380 if (status != EFI_SUCCESS) {
381 efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
385 status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
387 if (status == EFI_BUFFER_TOO_SMALL) {
388 efi_call_early(free_pool, info);
392 *file_sz = info->file_size;
393 efi_call_early(free_pool, info);
395 if (status != EFI_SUCCESS)
396 efi_printk(sys_table_arg, "Failed to get initrd info\n");
401 static efi_status_t efi_file_read(void *handle, unsigned long *size, void *addr)
403 return efi_call_proto(efi_file_handle, read, handle, size, addr);
406 static efi_status_t efi_file_close(void *handle)
408 return efi_call_proto(efi_file_handle, close, handle);
412 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
413 * option, e.g. efi=nochunk.
415 * It should be noted that efi= is parsed in two very different
416 * environments, first in the early boot environment of the EFI boot
417 * stub, and subsequently during the kernel boot.
419 efi_status_t efi_parse_options(char const *cmdline)
423 str = strstr(cmdline, "nokaslr");
424 if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
428 * If no EFI parameters were specified on the cmdline we've got
431 str = strstr(cmdline, "efi=");
435 /* Skip ahead to first argument */
436 str += strlen("efi=");
439 * Remember, because efi= is also used by the kernel we need to
440 * skip over arguments we don't understand.
442 while (*str && *str != ' ') {
443 if (!strncmp(str, "nochunk", 7)) {
444 str += strlen("nochunk");
448 /* Group words together, delimited by "," */
449 while (*str && *str != ' ' && *str != ',')
460 * Check the cmdline for a LILO-style file= arguments.
462 * We only support loading a file from the same filesystem as
465 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
466 efi_loaded_image_t *image,
467 char *cmd_line, char *option_string,
468 unsigned long max_addr,
469 unsigned long *load_addr,
470 unsigned long *load_size)
472 struct file_info *files;
473 unsigned long file_addr;
475 efi_file_handle_t *fh = NULL;
486 j = 0; /* See close_handles */
488 if (!load_addr || !load_size)
489 return EFI_INVALID_PARAMETER;
497 for (nr_files = 0; *str; nr_files++) {
498 str = strstr(str, option_string);
502 str += strlen(option_string);
504 /* Skip any leading slashes */
505 while (*str == '/' || *str == '\\')
508 while (*str && *str != ' ' && *str != '\n')
515 status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
516 nr_files * sizeof(*files), (void **)&files);
517 if (status != EFI_SUCCESS) {
518 pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
523 for (i = 0; i < nr_files; i++) {
524 struct file_info *file;
525 efi_char16_t filename_16[256];
528 str = strstr(str, option_string);
532 str += strlen(option_string);
537 /* Skip any leading slashes */
538 while (*str == '/' || *str == '\\')
541 while (*str && *str != ' ' && *str != '\n') {
542 if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
555 /* Only open the volume once. */
557 status = efi_open_volume(sys_table_arg, image,
559 if (status != EFI_SUCCESS)
563 status = efi_file_size(sys_table_arg, fh, filename_16,
564 (void **)&file->handle, &file->size);
565 if (status != EFI_SUCCESS)
568 file_size_total += file->size;
571 if (file_size_total) {
575 * Multiple files need to be at consecutive addresses in memory,
576 * so allocate enough memory for all the files. This is used
577 * for loading multiple files.
579 status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
580 &file_addr, max_addr);
581 if (status != EFI_SUCCESS) {
582 pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
586 /* We've run out of free low memory. */
587 if (file_addr > max_addr) {
588 pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
589 status = EFI_INVALID_PARAMETER;
590 goto free_file_total;
594 for (j = 0; j < nr_files; j++) {
597 size = files[j].size;
599 unsigned long chunksize;
601 if (IS_ENABLED(CONFIG_X86) && size > __chunk_size)
602 chunksize = __chunk_size;
606 status = efi_file_read(files[j].handle,
609 if (status != EFI_SUCCESS) {
610 pr_efi_err(sys_table_arg, "Failed to read file\n");
611 goto free_file_total;
617 efi_file_close(files[j].handle);
622 efi_call_early(free_pool, files);
624 *load_addr = file_addr;
625 *load_size = file_size_total;
630 efi_free(sys_table_arg, file_size_total, file_addr);
633 for (k = j; k < i; k++)
634 efi_file_close(files[k].handle);
636 efi_call_early(free_pool, files);
644 * Relocate a kernel image, either compressed or uncompressed.
645 * In the ARM64 case, all kernel images are currently
646 * uncompressed, and as such when we relocate it we need to
647 * allocate additional space for the BSS segment. Any low
648 * memory that this function should avoid needs to be
649 * unavailable in the EFI memory map, as if the preferred
650 * address is not available the lowest available address will
653 efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
654 unsigned long *image_addr,
655 unsigned long image_size,
656 unsigned long alloc_size,
657 unsigned long preferred_addr,
658 unsigned long alignment)
660 unsigned long cur_image_addr;
661 unsigned long new_addr = 0;
663 unsigned long nr_pages;
664 efi_physical_addr_t efi_addr = preferred_addr;
666 if (!image_addr || !image_size || !alloc_size)
667 return EFI_INVALID_PARAMETER;
668 if (alloc_size < image_size)
669 return EFI_INVALID_PARAMETER;
671 cur_image_addr = *image_addr;
674 * The EFI firmware loader could have placed the kernel image
675 * anywhere in memory, but the kernel has restrictions on the
676 * max physical address it can run at. Some architectures
677 * also have a prefered address, so first try to relocate
678 * to the preferred address. If that fails, allocate as low
679 * as possible while respecting the required alignment.
681 nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
682 status = efi_call_early(allocate_pages,
683 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
684 nr_pages, &efi_addr);
687 * If preferred address allocation failed allocate as low as
690 if (status != EFI_SUCCESS) {
691 status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
694 if (status != EFI_SUCCESS) {
695 pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
700 * We know source/dest won't overlap since both memory ranges
701 * have been allocated by UEFI, so we can safely use memcpy.
703 memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
705 /* Return the new address of the relocated image. */
706 *image_addr = new_addr;
712 * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
713 * This overestimates for surrogates, but that is okay.
715 static int efi_utf8_bytes(u16 c)
717 return 1 + (c >= 0x80) + (c >= 0x800);
721 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
723 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
729 if (n && c >= 0xd800 && c <= 0xdbff &&
730 *src >= 0xdc00 && *src <= 0xdfff) {
731 c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
735 if (c >= 0xd800 && c <= 0xdfff)
736 c = 0xfffd; /* Unmatched surrogate */
742 *dst++ = 0xc0 + (c >> 6);
746 *dst++ = 0xe0 + (c >> 12);
749 *dst++ = 0xf0 + (c >> 18);
750 *dst++ = 0x80 + ((c >> 12) & 0x3f);
752 *dst++ = 0x80 + ((c >> 6) & 0x3f);
754 *dst++ = 0x80 + (c & 0x3f);
760 #ifndef MAX_CMDLINE_ADDRESS
761 #define MAX_CMDLINE_ADDRESS ULONG_MAX
765 * Convert the unicode UEFI command line to ASCII to pass to kernel.
766 * Size of memory allocated return in *cmd_line_len.
767 * Returns NULL on error.
769 char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
770 efi_loaded_image_t *image,
775 unsigned long cmdline_addr = 0;
776 int load_options_chars = image->load_options_size / 2; /* UTF-16 */
777 const u16 *options = image->load_options;
778 int options_bytes = 0; /* UTF-8 bytes */
779 int options_chars = 0; /* UTF-16 chars */
785 while (*s2 && *s2 != '\n'
786 && options_chars < load_options_chars) {
787 options_bytes += efi_utf8_bytes(*s2++);
792 if (!options_chars) {
793 /* No command line options, so return empty string*/
797 options_bytes++; /* NUL termination */
799 status = efi_high_alloc(sys_table_arg, options_bytes, 0,
800 &cmdline_addr, MAX_CMDLINE_ADDRESS);
801 if (status != EFI_SUCCESS)
804 s1 = (u8 *)cmdline_addr;
805 s2 = (const u16 *)options;
807 s1 = efi_utf16_to_utf8(s1, s2, options_chars);
810 *cmd_line_len = options_bytes;
811 return (char *)cmdline_addr;
815 * Handle calling ExitBootServices according to the requirements set out by the
816 * spec. Obtains the current memory map, and returns that info after calling
817 * ExitBootServices. The client must specify a function to perform any
818 * processing of the memory map data prior to ExitBootServices. A client
819 * specific structure may be passed to the function via priv. The client
820 * function may be called multiple times.
822 efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
824 struct efi_boot_memmap *map,
826 efi_exit_boot_map_processing priv_func)
830 status = efi_get_memory_map(sys_table_arg, map);
832 if (status != EFI_SUCCESS)
835 status = priv_func(sys_table_arg, map, priv);
836 if (status != EFI_SUCCESS)
839 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
841 if (status == EFI_INVALID_PARAMETER) {
843 * The memory map changed between efi_get_memory_map() and
844 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4:
845 * EFI_BOOT_SERVICES.ExitBootServices we need to get the
846 * updated map, and try again. The spec implies one retry
847 * should be sufficent, which is confirmed against the EDK2
848 * implementation. Per the spec, we can only invoke
849 * get_memory_map() and exit_boot_services() - we cannot alloc
850 * so efi_get_memory_map() cannot be used, and we must reuse
851 * the buffer. For all practical purposes, the headroom in the
852 * buffer should account for any changes in the map so the call
853 * to get_memory_map() is expected to succeed here.
855 *map->map_size = *map->buff_size;
856 status = efi_call_early(get_memory_map,
863 /* exit_boot_services() was called, thus cannot free */
864 if (status != EFI_SUCCESS)
867 status = priv_func(sys_table_arg, map, priv);
868 /* exit_boot_services() was called, thus cannot free */
869 if (status != EFI_SUCCESS)
872 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
875 /* exit_boot_services() was called, thus cannot free */
876 if (status != EFI_SUCCESS)
882 efi_call_early(free_pool, *map->map);