1 // SPDX-License-Identifier: GPL-2.0-only
3 * kexec: kexec_file_load system call
5 * Copyright (C) 2014 Red Hat Inc.
7 * Vivek Goyal <vgoyal@redhat.com>
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 #include <linux/capability.h>
14 #include <linux/file.h>
15 #include <linux/slab.h>
16 #include <linux/kexec.h>
17 #include <linux/memblock.h>
18 #include <linux/mutex.h>
19 #include <linux/list.h>
21 #include <linux/ima.h>
22 #include <crypto/hash.h>
23 #include <crypto/sha2.h>
24 #include <linux/elf.h>
25 #include <linux/elfcore.h>
26 #include <linux/kernel.h>
27 #include <linux/kernel_read_file.h>
28 #include <linux/syscalls.h>
29 #include <linux/vmalloc.h>
30 #include "kexec_internal.h"
32 #ifdef CONFIG_KEXEC_SIG
33 static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE);
35 void set_kexec_sig_enforced(void)
41 static int kexec_calculate_store_digests(struct kimage *image);
43 /* Maximum size in bytes for kernel/initrd files. */
44 #define KEXEC_FILE_SIZE_MAX min_t(s64, 4LL << 30, SSIZE_MAX)
47 * Currently this is the only default function that is exported as some
48 * architectures need it to do additional handlings.
49 * In the future, other default functions may be exported too if required.
51 int kexec_image_probe_default(struct kimage *image, void *buf,
52 unsigned long buf_len)
54 const struct kexec_file_ops * const *fops;
57 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
58 ret = (*fops)->probe(buf, buf_len);
68 static void *kexec_image_load_default(struct kimage *image)
70 if (!image->fops || !image->fops->load)
71 return ERR_PTR(-ENOEXEC);
73 return image->fops->load(image, image->kernel_buf,
74 image->kernel_buf_len, image->initrd_buf,
75 image->initrd_buf_len, image->cmdline_buf,
76 image->cmdline_buf_len);
79 int kexec_image_post_load_cleanup_default(struct kimage *image)
81 if (!image->fops || !image->fops->cleanup)
84 return image->fops->cleanup(image->image_loader_data);
88 * Free up memory used by kernel, initrd, and command line. This is temporary
89 * memory allocation which is not needed any more after these buffers have
90 * been loaded into separate segments and have been copied elsewhere.
92 void kimage_file_post_load_cleanup(struct kimage *image)
94 struct purgatory_info *pi = &image->purgatory_info;
96 vfree(image->kernel_buf);
97 image->kernel_buf = NULL;
99 vfree(image->initrd_buf);
100 image->initrd_buf = NULL;
102 kfree(image->cmdline_buf);
103 image->cmdline_buf = NULL;
105 vfree(pi->purgatory_buf);
106 pi->purgatory_buf = NULL;
111 #ifdef CONFIG_IMA_KEXEC
112 vfree(image->ima_buffer);
113 image->ima_buffer = NULL;
114 #endif /* CONFIG_IMA_KEXEC */
116 /* See if architecture has anything to cleanup post load */
117 arch_kimage_file_post_load_cleanup(image);
120 * Above call should have called into bootloader to free up
121 * any data stored in kimage->image_loader_data. It should
122 * be ok now to free it up.
124 kfree(image->image_loader_data);
125 image->image_loader_data = NULL;
127 kexec_file_dbg_print = false;
130 #ifdef CONFIG_KEXEC_SIG
131 #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
132 int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len)
136 ret = verify_pefile_signature(kernel, kernel_len,
137 VERIFY_USE_SECONDARY_KEYRING,
138 VERIFYING_KEXEC_PE_SIGNATURE);
139 if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
140 ret = verify_pefile_signature(kernel, kernel_len,
141 VERIFY_USE_PLATFORM_KEYRING,
142 VERIFYING_KEXEC_PE_SIGNATURE);
148 static int kexec_image_verify_sig(struct kimage *image, void *buf,
149 unsigned long buf_len)
151 if (!image->fops || !image->fops->verify_sig) {
152 pr_debug("kernel loader does not support signature verification.\n");
153 return -EKEYREJECTED;
156 return image->fops->verify_sig(buf, buf_len);
160 kimage_validate_signature(struct kimage *image)
164 ret = kexec_image_verify_sig(image, image->kernel_buf,
165 image->kernel_buf_len);
169 pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
174 * If IMA is guaranteed to appraise a signature on the kexec
175 * image, permit it even if the kernel is otherwise locked
178 if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
179 security_locked_down(LOCKDOWN_KEXEC))
182 pr_debug("kernel signature verification failed (%d).\n", ret);
190 * In file mode list of segments is prepared by kernel. Copy relevant
191 * data from user space, do error checking, prepare segment list
194 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
195 const char __user *cmdline_ptr,
196 unsigned long cmdline_len, unsigned flags)
201 ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
202 KEXEC_FILE_SIZE_MAX, NULL,
203 READING_KEXEC_IMAGE);
206 image->kernel_buf_len = ret;
207 kexec_dprintk("kernel: %p kernel_size: %#lx\n",
208 image->kernel_buf, image->kernel_buf_len);
210 /* Call arch image probe handlers */
211 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
212 image->kernel_buf_len);
216 #ifdef CONFIG_KEXEC_SIG
217 ret = kimage_validate_signature(image);
222 /* It is possible that there no initramfs is being loaded */
223 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
224 ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
225 KEXEC_FILE_SIZE_MAX, NULL,
226 READING_KEXEC_INITRAMFS);
229 image->initrd_buf_len = ret;
234 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
235 if (IS_ERR(image->cmdline_buf)) {
236 ret = PTR_ERR(image->cmdline_buf);
237 image->cmdline_buf = NULL;
241 image->cmdline_buf_len = cmdline_len;
243 /* command line should be a string with last byte null */
244 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
249 ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
250 image->cmdline_buf_len - 1);
253 /* IMA needs to pass the measurement list to the next kernel. */
254 ima_add_kexec_buffer(image);
256 /* Call image load handler */
257 ldata = kexec_image_load_default(image);
260 ret = PTR_ERR(ldata);
264 image->image_loader_data = ldata;
266 /* In case of error, free up all allocated memory in this function */
268 kimage_file_post_load_cleanup(image);
273 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
274 int initrd_fd, const char __user *cmdline_ptr,
275 unsigned long cmdline_len, unsigned long flags)
278 struct kimage *image;
279 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
281 image = do_kimage_alloc_init();
285 kexec_file_dbg_print = !!(flags & KEXEC_FILE_DEBUG);
286 image->file_mode = 1;
288 #ifdef CONFIG_CRASH_DUMP
289 if (kexec_on_panic) {
290 /* Enable special crash kernel control page alloc policy. */
291 image->control_page = crashk_res.start;
292 image->type = KEXEC_TYPE_CRASH;
296 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
297 cmdline_ptr, cmdline_len, flags);
301 ret = sanity_check_segment_list(image);
303 goto out_free_post_load_bufs;
306 image->control_code_page = kimage_alloc_control_pages(image,
307 get_order(KEXEC_CONTROL_PAGE_SIZE));
308 if (!image->control_code_page) {
309 pr_err("Could not allocate control_code_buffer\n");
310 goto out_free_post_load_bufs;
313 if (!kexec_on_panic) {
314 image->swap_page = kimage_alloc_control_pages(image, 0);
315 if (!image->swap_page) {
316 pr_err("Could not allocate swap buffer\n");
317 goto out_free_control_pages;
323 out_free_control_pages:
324 kimage_free_page_list(&image->control_pages);
325 out_free_post_load_bufs:
326 kimage_file_post_load_cleanup(image);
332 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
333 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
334 unsigned long, flags)
336 int image_type = (flags & KEXEC_FILE_ON_CRASH) ?
337 KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT;
338 struct kimage **dest_image, *image;
341 /* We only trust the superuser with rebooting the system. */
342 if (!kexec_load_permitted(image_type))
345 /* Make sure we have a legal set of flags */
346 if (flags != (flags & KEXEC_FILE_FLAGS))
351 if (!kexec_trylock())
354 #ifdef CONFIG_CRASH_DUMP
355 if (image_type == KEXEC_TYPE_CRASH) {
356 dest_image = &kexec_crash_image;
357 if (kexec_crash_image)
358 arch_kexec_unprotect_crashkres();
361 dest_image = &kexec_image;
363 if (flags & KEXEC_FILE_UNLOAD)
367 * In case of crash, new kernel gets loaded in reserved region. It is
368 * same memory where old crash kernel might be loaded. Free any
369 * current crash dump kernel before we corrupt it.
371 if (flags & KEXEC_FILE_ON_CRASH)
372 kimage_free(xchg(&kexec_crash_image, NULL));
374 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
379 ret = machine_kexec_prepare(image);
384 * Some architecture(like S390) may touch the crash memory before
385 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
387 ret = kimage_crash_copy_vmcoreinfo(image);
391 ret = kexec_calculate_store_digests(image);
395 kexec_dprintk("nr_segments = %lu\n", image->nr_segments);
396 for (i = 0; i < image->nr_segments; i++) {
397 struct kexec_segment *ksegment;
399 ksegment = &image->segment[i];
400 kexec_dprintk("segment[%d]: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
401 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
404 ret = kimage_load_segment(image, &image->segment[i]);
409 kimage_terminate(image);
411 ret = machine_kexec_post_load(image);
415 kexec_dprintk("kexec_file_load: type:%u, start:0x%lx head:0x%lx flags:0x%lx\n",
416 image->type, image->start, image->head, flags);
418 * Free up any temporary buffers allocated which are not needed
419 * after image has been loaded
421 kimage_file_post_load_cleanup(image);
423 image = xchg(dest_image, image);
425 #ifdef CONFIG_CRASH_DUMP
426 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
427 arch_kexec_protect_crashkres();
435 static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
436 struct kexec_buf *kbuf)
438 struct kimage *image = kbuf->image;
439 unsigned long temp_start, temp_end;
441 temp_end = min(end, kbuf->buf_max);
442 temp_start = temp_end - kbuf->memsz + 1;
445 /* align down start */
446 temp_start = ALIGN_DOWN(temp_start, kbuf->buf_align);
448 if (temp_start < start || temp_start < kbuf->buf_min)
451 temp_end = temp_start + kbuf->memsz - 1;
454 * Make sure this does not conflict with any of existing
457 if (kimage_is_destination_range(image, temp_start, temp_end)) {
458 temp_start = temp_start - PAGE_SIZE;
462 /* We found a suitable memory range */
466 /* If we are here, we found a suitable memory range */
467 kbuf->mem = temp_start;
469 /* Success, stop navigating through remaining System RAM ranges */
473 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
474 struct kexec_buf *kbuf)
476 struct kimage *image = kbuf->image;
477 unsigned long temp_start, temp_end;
479 temp_start = max(start, kbuf->buf_min);
482 temp_start = ALIGN(temp_start, kbuf->buf_align);
483 temp_end = temp_start + kbuf->memsz - 1;
485 if (temp_end > end || temp_end > kbuf->buf_max)
488 * Make sure this does not conflict with any of existing
491 if (kimage_is_destination_range(image, temp_start, temp_end)) {
492 temp_start = temp_start + PAGE_SIZE;
496 /* We found a suitable memory range */
500 /* If we are here, we found a suitable memory range */
501 kbuf->mem = temp_start;
503 /* Success, stop navigating through remaining System RAM ranges */
507 static int locate_mem_hole_callback(struct resource *res, void *arg)
509 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
510 u64 start = res->start, end = res->end;
511 unsigned long sz = end - start + 1;
513 /* Returning 0 will take to next memory range */
515 /* Don't use memory that will be detected and handled by a driver. */
516 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
519 if (sz < kbuf->memsz)
522 if (end < kbuf->buf_min || start > kbuf->buf_max)
526 * Allocate memory top down with-in ram range. Otherwise bottom up
530 return locate_mem_hole_top_down(start, end, kbuf);
531 return locate_mem_hole_bottom_up(start, end, kbuf);
534 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
535 static int kexec_walk_memblock(struct kexec_buf *kbuf,
536 int (*func)(struct resource *, void *))
540 phys_addr_t mstart, mend;
541 struct resource res = { };
543 #ifdef CONFIG_CRASH_DUMP
544 if (kbuf->image->type == KEXEC_TYPE_CRASH)
545 return func(&crashk_res, kbuf);
549 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
550 * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
551 * locate_mem_hole_callback().
553 if (kbuf->top_down) {
554 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
555 &mstart, &mend, NULL) {
557 * In memblock, end points to the first byte after the
558 * range while in kexec, end points to the last byte
563 ret = func(&res, kbuf);
568 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
569 &mstart, &mend, NULL) {
571 * In memblock, end points to the first byte after the
572 * range while in kexec, end points to the last byte
577 ret = func(&res, kbuf);
586 static int kexec_walk_memblock(struct kexec_buf *kbuf,
587 int (*func)(struct resource *, void *))
594 * kexec_walk_resources - call func(data) on free memory regions
595 * @kbuf: Context info for the search. Also passed to @func.
596 * @func: Function to call for each memory region.
598 * Return: The memory walk will stop when func returns a non-zero value
599 * and that value will be returned. If all free regions are visited without
600 * func returning non-zero, then zero will be returned.
602 static int kexec_walk_resources(struct kexec_buf *kbuf,
603 int (*func)(struct resource *, void *))
605 #ifdef CONFIG_CRASH_DUMP
606 if (kbuf->image->type == KEXEC_TYPE_CRASH)
607 return walk_iomem_res_desc(crashk_res.desc,
608 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
609 crashk_res.start, crashk_res.end,
613 return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func);
615 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
619 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
620 * @kbuf: Parameters for the memory search.
622 * On success, kbuf->mem will have the start address of the memory region found.
624 * Return: 0 on success, negative errno on error.
626 int kexec_locate_mem_hole(struct kexec_buf *kbuf)
630 /* Arch knows where to place */
631 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
634 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
635 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
637 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
639 return ret == 1 ? 0 : -EADDRNOTAVAIL;
643 * kexec_add_buffer - place a buffer in a kexec segment
644 * @kbuf: Buffer contents and memory parameters.
646 * This function assumes that kexec_lock is held.
647 * On successful return, @kbuf->mem will have the physical address of
648 * the buffer in memory.
650 * Return: 0 on success, negative errno on error.
652 int kexec_add_buffer(struct kexec_buf *kbuf)
654 struct kexec_segment *ksegment;
657 /* Currently adding segment this way is allowed only in file mode */
658 if (!kbuf->image->file_mode)
661 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
665 * Make sure we are not trying to add buffer after allocating
666 * control pages. All segments need to be placed first before
667 * any control pages are allocated. As control page allocation
668 * logic goes through list of segments to make sure there are
669 * no destination overlaps.
671 if (!list_empty(&kbuf->image->control_pages)) {
676 /* Ensure minimum alignment needed for segments. */
677 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
678 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
680 /* Walk the RAM ranges and allocate a suitable range for the buffer */
681 ret = arch_kexec_locate_mem_hole(kbuf);
685 /* Found a suitable memory range */
686 ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
687 ksegment->kbuf = kbuf->buffer;
688 ksegment->bufsz = kbuf->bufsz;
689 ksegment->mem = kbuf->mem;
690 ksegment->memsz = kbuf->memsz;
691 kbuf->image->nr_segments++;
695 /* Calculate and store the digest of segments */
696 static int kexec_calculate_store_digests(struct kimage *image)
698 struct crypto_shash *tfm;
699 struct shash_desc *desc;
700 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
701 size_t desc_size, nullsz;
704 struct kexec_sha_region *sha_regions;
705 struct purgatory_info *pi = &image->purgatory_info;
707 if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY))
710 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
711 zero_buf_sz = PAGE_SIZE;
713 tfm = crypto_alloc_shash("sha256", 0, 0);
719 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
720 desc = kzalloc(desc_size, GFP_KERNEL);
726 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
727 sha_regions = vzalloc(sha_region_sz);
735 ret = crypto_shash_init(desc);
737 goto out_free_sha_regions;
739 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
742 goto out_free_sha_regions;
745 for (j = i = 0; i < image->nr_segments; i++) {
746 struct kexec_segment *ksegment;
748 #ifdef CONFIG_CRASH_HOTPLUG
749 /* Exclude elfcorehdr segment to allow future changes via hotplug */
750 if (j == image->elfcorehdr_index)
754 ksegment = &image->segment[i];
756 * Skip purgatory as it will be modified once we put digest
759 if (ksegment->kbuf == pi->purgatory_buf)
762 ret = crypto_shash_update(desc, ksegment->kbuf,
768 * Assume rest of the buffer is filled with zero and
769 * update digest accordingly.
771 nullsz = ksegment->memsz - ksegment->bufsz;
773 unsigned long bytes = nullsz;
775 if (bytes > zero_buf_sz)
777 ret = crypto_shash_update(desc, zero_buf, bytes);
786 sha_regions[j].start = ksegment->mem;
787 sha_regions[j].len = ksegment->memsz;
792 ret = crypto_shash_final(desc, digest);
794 goto out_free_digest;
795 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
796 sha_regions, sha_region_sz, 0);
798 goto out_free_digest;
800 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
801 digest, SHA256_DIGEST_SIZE, 0);
803 goto out_free_digest;
808 out_free_sha_regions:
818 #ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
820 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
821 * @pi: Purgatory to be loaded.
822 * @kbuf: Buffer to setup.
824 * Allocates the memory needed for the buffer. Caller is responsible to free
825 * the memory after use.
827 * Return: 0 on success, negative errno on error.
829 static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
830 struct kexec_buf *kbuf)
832 const Elf_Shdr *sechdrs;
833 unsigned long bss_align;
834 unsigned long bss_sz;
838 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
839 kbuf->buf_align = bss_align = 1;
840 kbuf->bufsz = bss_sz = 0;
842 for (i = 0; i < pi->ehdr->e_shnum; i++) {
843 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
846 align = sechdrs[i].sh_addralign;
847 if (sechdrs[i].sh_type != SHT_NOBITS) {
848 if (kbuf->buf_align < align)
849 kbuf->buf_align = align;
850 kbuf->bufsz = ALIGN(kbuf->bufsz, align);
851 kbuf->bufsz += sechdrs[i].sh_size;
853 if (bss_align < align)
855 bss_sz = ALIGN(bss_sz, align);
856 bss_sz += sechdrs[i].sh_size;
859 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
860 kbuf->memsz = kbuf->bufsz + bss_sz;
861 if (kbuf->buf_align < bss_align)
862 kbuf->buf_align = bss_align;
864 kbuf->buffer = vzalloc(kbuf->bufsz);
867 pi->purgatory_buf = kbuf->buffer;
869 ret = kexec_add_buffer(kbuf);
875 vfree(pi->purgatory_buf);
876 pi->purgatory_buf = NULL;
881 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
882 * @pi: Purgatory to be loaded.
883 * @kbuf: Buffer prepared to store purgatory.
885 * Allocates the memory needed for the buffer. Caller is responsible to free
886 * the memory after use.
888 * Return: 0 on success, negative errno on error.
890 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
891 struct kexec_buf *kbuf)
893 unsigned long bss_addr;
894 unsigned long offset;
900 * The section headers in kexec_purgatory are read-only. In order to
901 * have them modifiable make a temporary copy.
903 sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum);
904 sechdrs = vzalloc(sechdrs_size);
907 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size);
908 pi->sechdrs = sechdrs;
911 bss_addr = kbuf->mem + kbuf->bufsz;
912 kbuf->image->start = pi->ehdr->e_entry;
914 for (i = 0; i < pi->ehdr->e_shnum; i++) {
918 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
921 align = sechdrs[i].sh_addralign;
922 if (sechdrs[i].sh_type == SHT_NOBITS) {
923 bss_addr = ALIGN(bss_addr, align);
924 sechdrs[i].sh_addr = bss_addr;
925 bss_addr += sechdrs[i].sh_size;
929 offset = ALIGN(offset, align);
932 * Check if the segment contains the entry point, if so,
933 * calculate the value of image->start based on it.
934 * If the compiler has produced more than one .text section
935 * (Eg: .text.hot), they are generally after the main .text
936 * section, and they shall not be used to calculate
937 * image->start. So do not re-calculate image->start if it
938 * is not set to the initial value, and warn the user so they
939 * have a chance to fix their purgatory's linker script.
941 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
942 pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
943 pi->ehdr->e_entry < (sechdrs[i].sh_addr
944 + sechdrs[i].sh_size) &&
945 !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) {
946 kbuf->image->start -= sechdrs[i].sh_addr;
947 kbuf->image->start += kbuf->mem + offset;
950 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
951 dst = pi->purgatory_buf + offset;
952 memcpy(dst, src, sechdrs[i].sh_size);
954 sechdrs[i].sh_addr = kbuf->mem + offset;
955 sechdrs[i].sh_offset = offset;
956 offset += sechdrs[i].sh_size;
962 static int kexec_apply_relocations(struct kimage *image)
965 struct purgatory_info *pi = &image->purgatory_info;
966 const Elf_Shdr *sechdrs;
968 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
970 for (i = 0; i < pi->ehdr->e_shnum; i++) {
971 const Elf_Shdr *relsec;
972 const Elf_Shdr *symtab;
975 relsec = sechdrs + i;
977 if (relsec->sh_type != SHT_RELA &&
978 relsec->sh_type != SHT_REL)
982 * For section of type SHT_RELA/SHT_REL,
983 * ->sh_link contains section header index of associated
984 * symbol table. And ->sh_info contains section header
985 * index of section to which relocations apply.
987 if (relsec->sh_info >= pi->ehdr->e_shnum ||
988 relsec->sh_link >= pi->ehdr->e_shnum)
991 section = pi->sechdrs + relsec->sh_info;
992 symtab = sechdrs + relsec->sh_link;
994 if (!(section->sh_flags & SHF_ALLOC))
998 * symtab->sh_link contain section header index of associated
1001 if (symtab->sh_link >= pi->ehdr->e_shnum)
1002 /* Invalid section number? */
1006 * Respective architecture needs to provide support for applying
1007 * relocations of type SHT_RELA/SHT_REL.
1009 if (relsec->sh_type == SHT_RELA)
1010 ret = arch_kexec_apply_relocations_add(pi, section,
1012 else if (relsec->sh_type == SHT_REL)
1013 ret = arch_kexec_apply_relocations(pi, section,
1023 * kexec_load_purgatory - Load and relocate the purgatory object.
1024 * @image: Image to add the purgatory to.
1025 * @kbuf: Memory parameters to use.
1027 * Allocates the memory needed for image->purgatory_info.sechdrs and
1028 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
1029 * to free the memory after use.
1031 * Return: 0 on success, negative errno on error.
1033 int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
1035 struct purgatory_info *pi = &image->purgatory_info;
1038 if (kexec_purgatory_size <= 0)
1041 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
1043 ret = kexec_purgatory_setup_kbuf(pi, kbuf);
1047 ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
1051 ret = kexec_apply_relocations(image);
1060 vfree(pi->purgatory_buf);
1061 pi->purgatory_buf = NULL;
1066 * kexec_purgatory_find_symbol - find a symbol in the purgatory
1067 * @pi: Purgatory to search in.
1068 * @name: Name of the symbol.
1070 * Return: pointer to symbol in read-only symtab on success, NULL on error.
1072 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1075 const Elf_Shdr *sechdrs;
1076 const Elf_Ehdr *ehdr;
1077 const Elf_Sym *syms;
1085 sechdrs = (void *)ehdr + ehdr->e_shoff;
1087 for (i = 0; i < ehdr->e_shnum; i++) {
1088 if (sechdrs[i].sh_type != SHT_SYMTAB)
1091 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1092 /* Invalid strtab section number */
1094 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1095 syms = (void *)ehdr + sechdrs[i].sh_offset;
1097 /* Go through symbols for a match */
1098 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1099 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1102 if (strcmp(strtab + syms[k].st_name, name) != 0)
1105 if (syms[k].st_shndx == SHN_UNDEF ||
1106 syms[k].st_shndx >= ehdr->e_shnum) {
1107 pr_debug("Symbol: %s has bad section index %d.\n",
1108 name, syms[k].st_shndx);
1112 /* Found the symbol we are looking for */
1120 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1122 struct purgatory_info *pi = &image->purgatory_info;
1126 sym = kexec_purgatory_find_symbol(pi, name);
1128 return ERR_PTR(-EINVAL);
1130 sechdr = &pi->sechdrs[sym->st_shndx];
1133 * Returns the address where symbol will finally be loaded after
1134 * kexec_load_segment()
1136 return (void *)(sechdr->sh_addr + sym->st_value);
1140 * Get or set value of a symbol. If "get_value" is true, symbol value is
1141 * returned in buf otherwise symbol value is set based on value in buf.
1143 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1144 void *buf, unsigned int size, bool get_value)
1146 struct purgatory_info *pi = &image->purgatory_info;
1151 sym = kexec_purgatory_find_symbol(pi, name);
1155 if (sym->st_size != size) {
1156 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1157 name, (unsigned long)sym->st_size, size);
1161 sec = pi->sechdrs + sym->st_shndx;
1163 if (sec->sh_type == SHT_NOBITS) {
1164 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1165 get_value ? "get" : "set");
1169 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1172 memcpy((void *)buf, sym_buf, size);
1174 memcpy((void *)sym_buf, buf, size);
1178 #endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */