2 * kexec: kexec_file_load system call
4 * Copyright (C) 2014 Red Hat Inc.
6 * Vivek Goyal <vgoyal@redhat.com>
8 * This source code is licensed under the GNU General Public License,
9 * Version 2. See the file COPYING for more details.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <linux/capability.h>
16 #include <linux/file.h>
17 #include <linux/slab.h>
18 #include <linux/kexec.h>
19 #include <linux/mutex.h>
20 #include <linux/list.h>
22 #include <linux/ima.h>
23 #include <crypto/hash.h>
24 #include <crypto/sha.h>
25 #include <linux/syscalls.h>
26 #include <linux/vmalloc.h>
27 #include "kexec_internal.h"
30 * Declare these symbols weak so that if architecture provides a purgatory,
31 * these will be overridden.
33 char __weak kexec_purgatory[0];
34 size_t __weak kexec_purgatory_size = 0;
36 static int kexec_calculate_store_digests(struct kimage *image);
38 /* Architectures can provide this probe function */
39 int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
40 unsigned long buf_len)
45 void * __weak arch_kexec_kernel_image_load(struct kimage *image)
47 return ERR_PTR(-ENOEXEC);
50 int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
55 #ifdef CONFIG_KEXEC_VERIFY_SIG
56 int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
57 unsigned long buf_len)
63 /* Apply relocations of type RELA */
65 arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
68 pr_err("RELA relocation unsupported.\n");
72 /* Apply relocations of type REL */
74 arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
77 pr_err("REL relocation unsupported.\n");
82 * Free up memory used by kernel, initrd, and command line. This is temporary
83 * memory allocation which is not needed any more after these buffers have
84 * been loaded into separate segments and have been copied elsewhere.
86 void kimage_file_post_load_cleanup(struct kimage *image)
88 struct purgatory_info *pi = &image->purgatory_info;
90 vfree(image->kernel_buf);
91 image->kernel_buf = NULL;
93 vfree(image->initrd_buf);
94 image->initrd_buf = NULL;
96 kfree(image->cmdline_buf);
97 image->cmdline_buf = NULL;
99 vfree(pi->purgatory_buf);
100 pi->purgatory_buf = NULL;
105 /* See if architecture has anything to cleanup post load */
106 arch_kimage_file_post_load_cleanup(image);
109 * Above call should have called into bootloader to free up
110 * any data stored in kimage->image_loader_data. It should
111 * be ok now to free it up.
113 kfree(image->image_loader_data);
114 image->image_loader_data = NULL;
118 * In file mode list of segments is prepared by kernel. Copy relevant
119 * data from user space, do error checking, prepare segment list
122 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
123 const char __user *cmdline_ptr,
124 unsigned long cmdline_len, unsigned flags)
130 ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
131 &size, INT_MAX, READING_KEXEC_IMAGE);
134 image->kernel_buf_len = size;
136 /* IMA needs to pass the measurement list to the next kernel. */
137 ima_add_kexec_buffer(image);
139 /* Call arch image probe handlers */
140 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
141 image->kernel_buf_len);
145 #ifdef CONFIG_KEXEC_VERIFY_SIG
146 ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
147 image->kernel_buf_len);
149 pr_debug("kernel signature verification failed.\n");
152 pr_debug("kernel signature verification successful.\n");
154 /* It is possible that there no initramfs is being loaded */
155 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
156 ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
158 READING_KEXEC_INITRAMFS);
161 image->initrd_buf_len = size;
165 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
166 if (IS_ERR(image->cmdline_buf)) {
167 ret = PTR_ERR(image->cmdline_buf);
168 image->cmdline_buf = NULL;
172 image->cmdline_buf_len = cmdline_len;
174 /* command line should be a string with last byte null */
175 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
181 /* Call arch image load handlers */
182 ldata = arch_kexec_kernel_image_load(image);
185 ret = PTR_ERR(ldata);
189 image->image_loader_data = ldata;
191 /* In case of error, free up all allocated memory in this function */
193 kimage_file_post_load_cleanup(image);
198 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
199 int initrd_fd, const char __user *cmdline_ptr,
200 unsigned long cmdline_len, unsigned long flags)
203 struct kimage *image;
204 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
206 image = do_kimage_alloc_init();
210 image->file_mode = 1;
212 if (kexec_on_panic) {
213 /* Enable special crash kernel control page alloc policy. */
214 image->control_page = crashk_res.start;
215 image->type = KEXEC_TYPE_CRASH;
218 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
219 cmdline_ptr, cmdline_len, flags);
223 ret = sanity_check_segment_list(image);
225 goto out_free_post_load_bufs;
228 image->control_code_page = kimage_alloc_control_pages(image,
229 get_order(KEXEC_CONTROL_PAGE_SIZE));
230 if (!image->control_code_page) {
231 pr_err("Could not allocate control_code_buffer\n");
232 goto out_free_post_load_bufs;
235 if (!kexec_on_panic) {
236 image->swap_page = kimage_alloc_control_pages(image, 0);
237 if (!image->swap_page) {
238 pr_err("Could not allocate swap buffer\n");
239 goto out_free_control_pages;
245 out_free_control_pages:
246 kimage_free_page_list(&image->control_pages);
247 out_free_post_load_bufs:
248 kimage_file_post_load_cleanup(image);
254 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
255 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
256 unsigned long, flags)
259 struct kimage **dest_image, *image;
261 /* We only trust the superuser with rebooting the system. */
262 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
265 /* Make sure we have a legal set of flags */
266 if (flags != (flags & KEXEC_FILE_FLAGS))
271 if (!mutex_trylock(&kexec_mutex))
274 dest_image = &kexec_image;
275 if (flags & KEXEC_FILE_ON_CRASH) {
276 dest_image = &kexec_crash_image;
277 if (kexec_crash_image)
278 arch_kexec_unprotect_crashkres();
281 if (flags & KEXEC_FILE_UNLOAD)
285 * In case of crash, new kernel gets loaded in reserved region. It is
286 * same memory where old crash kernel might be loaded. Free any
287 * current crash dump kernel before we corrupt it.
289 if (flags & KEXEC_FILE_ON_CRASH)
290 kimage_free(xchg(&kexec_crash_image, NULL));
292 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
297 ret = machine_kexec_prepare(image);
302 * Some architecture(like S390) may touch the crash memory before
303 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
305 ret = kimage_crash_copy_vmcoreinfo(image);
309 ret = kexec_calculate_store_digests(image);
313 for (i = 0; i < image->nr_segments; i++) {
314 struct kexec_segment *ksegment;
316 ksegment = &image->segment[i];
317 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
318 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
321 ret = kimage_load_segment(image, &image->segment[i]);
326 kimage_terminate(image);
329 * Free up any temporary buffers allocated which are not needed
330 * after image has been loaded
332 kimage_file_post_load_cleanup(image);
334 image = xchg(dest_image, image);
336 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
337 arch_kexec_protect_crashkres();
339 mutex_unlock(&kexec_mutex);
344 static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
345 struct kexec_buf *kbuf)
347 struct kimage *image = kbuf->image;
348 unsigned long temp_start, temp_end;
350 temp_end = min(end, kbuf->buf_max);
351 temp_start = temp_end - kbuf->memsz;
354 /* align down start */
355 temp_start = temp_start & (~(kbuf->buf_align - 1));
357 if (temp_start < start || temp_start < kbuf->buf_min)
360 temp_end = temp_start + kbuf->memsz - 1;
363 * Make sure this does not conflict with any of existing
366 if (kimage_is_destination_range(image, temp_start, temp_end)) {
367 temp_start = temp_start - PAGE_SIZE;
371 /* We found a suitable memory range */
375 /* If we are here, we found a suitable memory range */
376 kbuf->mem = temp_start;
378 /* Success, stop navigating through remaining System RAM ranges */
382 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
383 struct kexec_buf *kbuf)
385 struct kimage *image = kbuf->image;
386 unsigned long temp_start, temp_end;
388 temp_start = max(start, kbuf->buf_min);
391 temp_start = ALIGN(temp_start, kbuf->buf_align);
392 temp_end = temp_start + kbuf->memsz - 1;
394 if (temp_end > end || temp_end > kbuf->buf_max)
397 * Make sure this does not conflict with any of existing
400 if (kimage_is_destination_range(image, temp_start, temp_end)) {
401 temp_start = temp_start + PAGE_SIZE;
405 /* We found a suitable memory range */
409 /* If we are here, we found a suitable memory range */
410 kbuf->mem = temp_start;
412 /* Success, stop navigating through remaining System RAM ranges */
416 static int locate_mem_hole_callback(u64 start, u64 end, void *arg)
418 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
419 unsigned long sz = end - start + 1;
421 /* Returning 0 will take to next memory range */
422 if (sz < kbuf->memsz)
425 if (end < kbuf->buf_min || start > kbuf->buf_max)
429 * Allocate memory top down with-in ram range. Otherwise bottom up
433 return locate_mem_hole_top_down(start, end, kbuf);
434 return locate_mem_hole_bottom_up(start, end, kbuf);
438 * arch_kexec_walk_mem - call func(data) on free memory regions
439 * @kbuf: Context info for the search. Also passed to @func.
440 * @func: Function to call for each memory region.
442 * Return: The memory walk will stop when func returns a non-zero value
443 * and that value will be returned. If all free regions are visited without
444 * func returning non-zero, then zero will be returned.
446 int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
447 int (*func)(u64, u64, void *))
449 if (kbuf->image->type == KEXEC_TYPE_CRASH)
450 return walk_iomem_res_desc(crashk_res.desc,
451 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
452 crashk_res.start, crashk_res.end,
455 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
459 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
460 * @kbuf: Parameters for the memory search.
462 * On success, kbuf->mem will have the start address of the memory region found.
464 * Return: 0 on success, negative errno on error.
466 int kexec_locate_mem_hole(struct kexec_buf *kbuf)
470 ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
472 return ret == 1 ? 0 : -EADDRNOTAVAIL;
476 * kexec_add_buffer - place a buffer in a kexec segment
477 * @kbuf: Buffer contents and memory parameters.
479 * This function assumes that kexec_mutex is held.
480 * On successful return, @kbuf->mem will have the physical address of
481 * the buffer in memory.
483 * Return: 0 on success, negative errno on error.
485 int kexec_add_buffer(struct kexec_buf *kbuf)
488 struct kexec_segment *ksegment;
491 /* Currently adding segment this way is allowed only in file mode */
492 if (!kbuf->image->file_mode)
495 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
499 * Make sure we are not trying to add buffer after allocating
500 * control pages. All segments need to be placed first before
501 * any control pages are allocated. As control page allocation
502 * logic goes through list of segments to make sure there are
503 * no destination overlaps.
505 if (!list_empty(&kbuf->image->control_pages)) {
510 /* Ensure minimum alignment needed for segments. */
511 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
512 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
514 /* Walk the RAM ranges and allocate a suitable range for the buffer */
515 ret = kexec_locate_mem_hole(kbuf);
519 /* Found a suitable memory range */
520 ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
521 ksegment->kbuf = kbuf->buffer;
522 ksegment->bufsz = kbuf->bufsz;
523 ksegment->mem = kbuf->mem;
524 ksegment->memsz = kbuf->memsz;
525 kbuf->image->nr_segments++;
529 /* Calculate and store the digest of segments */
530 static int kexec_calculate_store_digests(struct kimage *image)
532 struct crypto_shash *tfm;
533 struct shash_desc *desc;
534 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
535 size_t desc_size, nullsz;
538 struct kexec_sha_region *sha_regions;
539 struct purgatory_info *pi = &image->purgatory_info;
541 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
542 zero_buf_sz = PAGE_SIZE;
544 tfm = crypto_alloc_shash("sha256", 0, 0);
550 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
551 desc = kzalloc(desc_size, GFP_KERNEL);
557 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
558 sha_regions = vzalloc(sha_region_sz);
565 ret = crypto_shash_init(desc);
567 goto out_free_sha_regions;
569 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
572 goto out_free_sha_regions;
575 for (j = i = 0; i < image->nr_segments; i++) {
576 struct kexec_segment *ksegment;
578 ksegment = &image->segment[i];
580 * Skip purgatory as it will be modified once we put digest
583 if (ksegment->kbuf == pi->purgatory_buf)
586 ret = crypto_shash_update(desc, ksegment->kbuf,
592 * Assume rest of the buffer is filled with zero and
593 * update digest accordingly.
595 nullsz = ksegment->memsz - ksegment->bufsz;
597 unsigned long bytes = nullsz;
599 if (bytes > zero_buf_sz)
601 ret = crypto_shash_update(desc, zero_buf, bytes);
610 sha_regions[j].start = ksegment->mem;
611 sha_regions[j].len = ksegment->memsz;
616 ret = crypto_shash_final(desc, digest);
618 goto out_free_digest;
619 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
620 sha_regions, sha_region_sz, 0);
622 goto out_free_digest;
624 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
625 digest, SHA256_DIGEST_SIZE, 0);
627 goto out_free_digest;
632 out_free_sha_regions:
642 /* Actually load purgatory. Lot of code taken from kexec-tools */
643 static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
644 unsigned long max, int top_down)
646 struct purgatory_info *pi = &image->purgatory_info;
647 unsigned long align, bss_align, bss_sz, bss_pad;
648 unsigned long entry, load_addr, curr_load_addr, bss_addr, offset;
649 unsigned char *buf_addr, *src;
650 int i, ret = 0, entry_sidx = -1;
651 const Elf_Shdr *sechdrs_c;
652 Elf_Shdr *sechdrs = NULL;
653 struct kexec_buf kbuf = { .image = image, .bufsz = 0, .buf_align = 1,
654 .buf_min = min, .buf_max = max,
655 .top_down = top_down };
658 * sechdrs_c points to section headers in purgatory and are read
659 * only. No modifications allowed.
661 sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff;
664 * We can not modify sechdrs_c[] and its fields. It is read only.
665 * Copy it over to a local copy where one can store some temporary
666 * data and free it at the end. We need to modify ->sh_addr and
667 * ->sh_offset fields to keep track of permanent and temporary
668 * locations of sections.
670 sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr));
674 memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr));
677 * We seem to have multiple copies of sections. First copy is which
678 * is embedded in kernel in read only section. Some of these sections
679 * will be copied to a temporary buffer and relocated. And these
680 * sections will finally be copied to their final destination at
683 * Use ->sh_offset to reflect section address in memory. It will
684 * point to original read only copy if section is not allocatable.
685 * Otherwise it will point to temporary copy which will be relocated.
687 * Use ->sh_addr to contain final address of the section where it
688 * will go during execution time.
690 for (i = 0; i < pi->ehdr->e_shnum; i++) {
691 if (sechdrs[i].sh_type == SHT_NOBITS)
694 sechdrs[i].sh_offset = (unsigned long)pi->ehdr +
695 sechdrs[i].sh_offset;
699 * Identify entry point section and make entry relative to section
702 entry = pi->ehdr->e_entry;
703 for (i = 0; i < pi->ehdr->e_shnum; i++) {
704 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
707 if (!(sechdrs[i].sh_flags & SHF_EXECINSTR))
710 /* Make entry section relative */
711 if (sechdrs[i].sh_addr <= pi->ehdr->e_entry &&
712 ((sechdrs[i].sh_addr + sechdrs[i].sh_size) >
713 pi->ehdr->e_entry)) {
715 entry -= sechdrs[i].sh_addr;
720 /* Determine how much memory is needed to load relocatable object. */
724 for (i = 0; i < pi->ehdr->e_shnum; i++) {
725 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
728 align = sechdrs[i].sh_addralign;
729 if (sechdrs[i].sh_type != SHT_NOBITS) {
730 if (kbuf.buf_align < align)
731 kbuf.buf_align = align;
732 kbuf.bufsz = ALIGN(kbuf.bufsz, align);
733 kbuf.bufsz += sechdrs[i].sh_size;
736 if (bss_align < align)
738 bss_sz = ALIGN(bss_sz, align);
739 bss_sz += sechdrs[i].sh_size;
743 /* Determine the bss padding required to align bss properly */
745 if (kbuf.bufsz & (bss_align - 1))
746 bss_pad = bss_align - (kbuf.bufsz & (bss_align - 1));
748 kbuf.memsz = kbuf.bufsz + bss_pad + bss_sz;
750 /* Allocate buffer for purgatory */
751 kbuf.buffer = vzalloc(kbuf.bufsz);
757 if (kbuf.buf_align < bss_align)
758 kbuf.buf_align = bss_align;
760 /* Add buffer to segment list */
761 ret = kexec_add_buffer(&kbuf);
764 pi->purgatory_load_addr = kbuf.mem;
766 /* Load SHF_ALLOC sections */
767 buf_addr = kbuf.buffer;
768 load_addr = curr_load_addr = pi->purgatory_load_addr;
769 bss_addr = load_addr + kbuf.bufsz + bss_pad;
771 for (i = 0; i < pi->ehdr->e_shnum; i++) {
772 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
775 align = sechdrs[i].sh_addralign;
776 if (sechdrs[i].sh_type != SHT_NOBITS) {
777 curr_load_addr = ALIGN(curr_load_addr, align);
778 offset = curr_load_addr - load_addr;
779 /* We already modifed ->sh_offset to keep src addr */
780 src = (char *) sechdrs[i].sh_offset;
781 memcpy(buf_addr + offset, src, sechdrs[i].sh_size);
783 /* Store load address and source address of section */
784 sechdrs[i].sh_addr = curr_load_addr;
787 * This section got copied to temporary buffer. Update
788 * ->sh_offset accordingly.
790 sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset);
792 /* Advance to the next address */
793 curr_load_addr += sechdrs[i].sh_size;
795 bss_addr = ALIGN(bss_addr, align);
796 sechdrs[i].sh_addr = bss_addr;
797 bss_addr += sechdrs[i].sh_size;
801 /* Update entry point based on load address of text section */
803 entry += sechdrs[entry_sidx].sh_addr;
805 /* Make kernel jump to purgatory after shutdown */
806 image->start = entry;
808 /* Used later to get/set symbol values */
809 pi->sechdrs = sechdrs;
812 * Used later to identify which section is purgatory and skip it
815 pi->purgatory_buf = kbuf.buffer;
823 static int kexec_apply_relocations(struct kimage *image)
826 struct purgatory_info *pi = &image->purgatory_info;
827 Elf_Shdr *sechdrs = pi->sechdrs;
829 /* Apply relocations */
830 for (i = 0; i < pi->ehdr->e_shnum; i++) {
831 Elf_Shdr *section, *symtab;
833 if (sechdrs[i].sh_type != SHT_RELA &&
834 sechdrs[i].sh_type != SHT_REL)
838 * For section of type SHT_RELA/SHT_REL,
839 * ->sh_link contains section header index of associated
840 * symbol table. And ->sh_info contains section header
841 * index of section to which relocations apply.
843 if (sechdrs[i].sh_info >= pi->ehdr->e_shnum ||
844 sechdrs[i].sh_link >= pi->ehdr->e_shnum)
847 section = &sechdrs[sechdrs[i].sh_info];
848 symtab = &sechdrs[sechdrs[i].sh_link];
850 if (!(section->sh_flags & SHF_ALLOC))
854 * symtab->sh_link contain section header index of associated
857 if (symtab->sh_link >= pi->ehdr->e_shnum)
858 /* Invalid section number? */
862 * Respective architecture needs to provide support for applying
863 * relocations of type SHT_RELA/SHT_REL.
865 if (sechdrs[i].sh_type == SHT_RELA)
866 ret = arch_kexec_apply_relocations_add(pi->ehdr,
868 else if (sechdrs[i].sh_type == SHT_REL)
869 ret = arch_kexec_apply_relocations(pi->ehdr,
878 /* Load relocatable purgatory object and relocate it appropriately */
879 int kexec_load_purgatory(struct kimage *image, unsigned long min,
880 unsigned long max, int top_down,
881 unsigned long *load_addr)
883 struct purgatory_info *pi = &image->purgatory_info;
886 if (kexec_purgatory_size <= 0)
889 if (kexec_purgatory_size < sizeof(Elf_Ehdr))
892 pi->ehdr = (Elf_Ehdr *)kexec_purgatory;
894 if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0
895 || pi->ehdr->e_type != ET_REL
896 || !elf_check_arch(pi->ehdr)
897 || pi->ehdr->e_shentsize != sizeof(Elf_Shdr))
900 if (pi->ehdr->e_shoff >= kexec_purgatory_size
901 || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) >
902 kexec_purgatory_size - pi->ehdr->e_shoff))
905 ret = __kexec_load_purgatory(image, min, max, top_down);
909 ret = kexec_apply_relocations(image);
913 *load_addr = pi->purgatory_load_addr;
919 vfree(pi->purgatory_buf);
920 pi->purgatory_buf = NULL;
924 static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
933 if (!pi->sechdrs || !pi->ehdr)
936 sechdrs = pi->sechdrs;
939 for (i = 0; i < ehdr->e_shnum; i++) {
940 if (sechdrs[i].sh_type != SHT_SYMTAB)
943 if (sechdrs[i].sh_link >= ehdr->e_shnum)
944 /* Invalid strtab section number */
946 strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset;
947 syms = (Elf_Sym *)sechdrs[i].sh_offset;
949 /* Go through symbols for a match */
950 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
951 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
954 if (strcmp(strtab + syms[k].st_name, name) != 0)
957 if (syms[k].st_shndx == SHN_UNDEF ||
958 syms[k].st_shndx >= ehdr->e_shnum) {
959 pr_debug("Symbol: %s has bad section index %d.\n",
960 name, syms[k].st_shndx);
964 /* Found the symbol we are looking for */
972 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
974 struct purgatory_info *pi = &image->purgatory_info;
978 sym = kexec_purgatory_find_symbol(pi, name);
980 return ERR_PTR(-EINVAL);
982 sechdr = &pi->sechdrs[sym->st_shndx];
985 * Returns the address where symbol will finally be loaded after
986 * kexec_load_segment()
988 return (void *)(sechdr->sh_addr + sym->st_value);
992 * Get or set value of a symbol. If "get_value" is true, symbol value is
993 * returned in buf otherwise symbol value is set based on value in buf.
995 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
996 void *buf, unsigned int size, bool get_value)
1000 struct purgatory_info *pi = &image->purgatory_info;
1003 sym = kexec_purgatory_find_symbol(pi, name);
1007 if (sym->st_size != size) {
1008 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1009 name, (unsigned long)sym->st_size, size);
1013 sechdrs = pi->sechdrs;
1015 if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
1016 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1017 get_value ? "get" : "set");
1021 sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset +
1025 memcpy((void *)buf, sym_buf, size);
1027 memcpy((void *)sym_buf, buf, size);