]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - kernel/kexec_file.c
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"
29 static int kexec_calculate_store_digests(struct kimage
*image
);
31 /* Architectures can provide this probe function */
32 int __weak
arch_kexec_kernel_image_probe(struct kimage
*image
, void *buf
,
33 unsigned long buf_len
)
38 void * __weak
arch_kexec_kernel_image_load(struct kimage
*image
)
40 return ERR_PTR(-ENOEXEC
);
43 int __weak
arch_kimage_file_post_load_cleanup(struct kimage
*image
)
48 #ifdef CONFIG_KEXEC_VERIFY_SIG
49 int __weak
arch_kexec_kernel_verify_sig(struct kimage
*image
, void *buf
,
50 unsigned long buf_len
)
56 /* Apply relocations of type RELA */
58 arch_kexec_apply_relocations_add(const Elf_Ehdr
*ehdr
, Elf_Shdr
*sechdrs
,
61 pr_err("RELA relocation unsupported.\n");
65 /* Apply relocations of type REL */
67 arch_kexec_apply_relocations(const Elf_Ehdr
*ehdr
, Elf_Shdr
*sechdrs
,
70 pr_err("REL relocation unsupported.\n");
75 * Free up memory used by kernel, initrd, and command line. This is temporary
76 * memory allocation which is not needed any more after these buffers have
77 * been loaded into separate segments and have been copied elsewhere.
79 void kimage_file_post_load_cleanup(struct kimage
*image
)
81 struct purgatory_info
*pi
= &image
->purgatory_info
;
83 vfree(image
->kernel_buf
);
84 image
->kernel_buf
= NULL
;
86 vfree(image
->initrd_buf
);
87 image
->initrd_buf
= NULL
;
89 kfree(image
->cmdline_buf
);
90 image
->cmdline_buf
= NULL
;
92 vfree(pi
->purgatory_buf
);
93 pi
->purgatory_buf
= NULL
;
98 /* See if architecture has anything to cleanup post load */
99 arch_kimage_file_post_load_cleanup(image
);
102 * Above call should have called into bootloader to free up
103 * any data stored in kimage->image_loader_data. It should
104 * be ok now to free it up.
106 kfree(image
->image_loader_data
);
107 image
->image_loader_data
= NULL
;
111 * In file mode list of segments is prepared by kernel. Copy relevant
112 * data from user space, do error checking, prepare segment list
115 kimage_file_prepare_segments(struct kimage
*image
, int kernel_fd
, int initrd_fd
,
116 const char __user
*cmdline_ptr
,
117 unsigned long cmdline_len
, unsigned flags
)
123 ret
= kernel_read_file_from_fd(kernel_fd
, &image
->kernel_buf
,
124 &size
, INT_MAX
, READING_KEXEC_IMAGE
);
127 image
->kernel_buf_len
= size
;
129 /* IMA needs to pass the measurement list to the next kernel. */
130 ima_add_kexec_buffer(image
);
132 /* Call arch image probe handlers */
133 ret
= arch_kexec_kernel_image_probe(image
, image
->kernel_buf
,
134 image
->kernel_buf_len
);
138 #ifdef CONFIG_KEXEC_VERIFY_SIG
139 ret
= arch_kexec_kernel_verify_sig(image
, image
->kernel_buf
,
140 image
->kernel_buf_len
);
142 pr_debug("kernel signature verification failed.\n");
145 pr_debug("kernel signature verification successful.\n");
147 /* It is possible that there no initramfs is being loaded */
148 if (!(flags
& KEXEC_FILE_NO_INITRAMFS
)) {
149 ret
= kernel_read_file_from_fd(initrd_fd
, &image
->initrd_buf
,
151 READING_KEXEC_INITRAMFS
);
154 image
->initrd_buf_len
= size
;
158 image
->cmdline_buf
= memdup_user(cmdline_ptr
, cmdline_len
);
159 if (IS_ERR(image
->cmdline_buf
)) {
160 ret
= PTR_ERR(image
->cmdline_buf
);
161 image
->cmdline_buf
= NULL
;
165 image
->cmdline_buf_len
= cmdline_len
;
167 /* command line should be a string with last byte null */
168 if (image
->cmdline_buf
[cmdline_len
- 1] != '\0') {
174 /* Call arch image load handlers */
175 ldata
= arch_kexec_kernel_image_load(image
);
178 ret
= PTR_ERR(ldata
);
182 image
->image_loader_data
= ldata
;
184 /* In case of error, free up all allocated memory in this function */
186 kimage_file_post_load_cleanup(image
);
191 kimage_file_alloc_init(struct kimage
**rimage
, int kernel_fd
,
192 int initrd_fd
, const char __user
*cmdline_ptr
,
193 unsigned long cmdline_len
, unsigned long flags
)
196 struct kimage
*image
;
197 bool kexec_on_panic
= flags
& KEXEC_FILE_ON_CRASH
;
199 image
= do_kimage_alloc_init();
203 image
->file_mode
= 1;
205 if (kexec_on_panic
) {
206 /* Enable special crash kernel control page alloc policy. */
207 image
->control_page
= crashk_res
.start
;
208 image
->type
= KEXEC_TYPE_CRASH
;
211 ret
= kimage_file_prepare_segments(image
, kernel_fd
, initrd_fd
,
212 cmdline_ptr
, cmdline_len
, flags
);
216 ret
= sanity_check_segment_list(image
);
218 goto out_free_post_load_bufs
;
221 image
->control_code_page
= kimage_alloc_control_pages(image
,
222 get_order(KEXEC_CONTROL_PAGE_SIZE
));
223 if (!image
->control_code_page
) {
224 pr_err("Could not allocate control_code_buffer\n");
225 goto out_free_post_load_bufs
;
228 if (!kexec_on_panic
) {
229 image
->swap_page
= kimage_alloc_control_pages(image
, 0);
230 if (!image
->swap_page
) {
231 pr_err("Could not allocate swap buffer\n");
232 goto out_free_control_pages
;
238 out_free_control_pages
:
239 kimage_free_page_list(&image
->control_pages
);
240 out_free_post_load_bufs
:
241 kimage_file_post_load_cleanup(image
);
247 SYSCALL_DEFINE5(kexec_file_load
, int, kernel_fd
, int, initrd_fd
,
248 unsigned long, cmdline_len
, const char __user
*, cmdline_ptr
,
249 unsigned long, flags
)
252 struct kimage
**dest_image
, *image
;
254 /* We only trust the superuser with rebooting the system. */
255 if (!capable(CAP_SYS_BOOT
) || kexec_load_disabled
)
258 /* Don't permit images to be loaded into trusted kernels if we're not
259 * going to verify the signature on them
261 if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG
) && kernel_is_locked_down())
264 /* Make sure we have a legal set of flags */
265 if (flags
!= (flags
& KEXEC_FILE_FLAGS
))
270 if (!mutex_trylock(&kexec_mutex
))
273 dest_image
= &kexec_image
;
274 if (flags
& KEXEC_FILE_ON_CRASH
) {
275 dest_image
= &kexec_crash_image
;
276 if (kexec_crash_image
)
277 arch_kexec_unprotect_crashkres();
280 if (flags
& KEXEC_FILE_UNLOAD
)
284 * In case of crash, new kernel gets loaded in reserved region. It is
285 * same memory where old crash kernel might be loaded. Free any
286 * current crash dump kernel before we corrupt it.
288 if (flags
& KEXEC_FILE_ON_CRASH
)
289 kimage_free(xchg(&kexec_crash_image
, NULL
));
291 ret
= kimage_file_alloc_init(&image
, kernel_fd
, initrd_fd
, cmdline_ptr
,
296 ret
= machine_kexec_prepare(image
);
301 * Some architecture(like S390) may touch the crash memory before
302 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
304 ret
= kimage_crash_copy_vmcoreinfo(image
);
308 ret
= kexec_calculate_store_digests(image
);
312 for (i
= 0; i
< image
->nr_segments
; i
++) {
313 struct kexec_segment
*ksegment
;
315 ksegment
= &image
->segment
[i
];
316 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
317 i
, ksegment
->buf
, ksegment
->bufsz
, ksegment
->mem
,
320 ret
= kimage_load_segment(image
, &image
->segment
[i
]);
325 kimage_terminate(image
);
328 * Free up any temporary buffers allocated which are not needed
329 * after image has been loaded
331 kimage_file_post_load_cleanup(image
);
333 image
= xchg(dest_image
, image
);
335 if ((flags
& KEXEC_FILE_ON_CRASH
) && kexec_crash_image
)
336 arch_kexec_protect_crashkres();
338 mutex_unlock(&kexec_mutex
);
343 static int locate_mem_hole_top_down(unsigned long start
, unsigned long end
,
344 struct kexec_buf
*kbuf
)
346 struct kimage
*image
= kbuf
->image
;
347 unsigned long temp_start
, temp_end
;
349 temp_end
= min(end
, kbuf
->buf_max
);
350 temp_start
= temp_end
- kbuf
->memsz
;
353 /* align down start */
354 temp_start
= temp_start
& (~(kbuf
->buf_align
- 1));
356 if (temp_start
< start
|| temp_start
< kbuf
->buf_min
)
359 temp_end
= temp_start
+ kbuf
->memsz
- 1;
362 * Make sure this does not conflict with any of existing
365 if (kimage_is_destination_range(image
, temp_start
, temp_end
)) {
366 temp_start
= temp_start
- PAGE_SIZE
;
370 /* We found a suitable memory range */
374 /* If we are here, we found a suitable memory range */
375 kbuf
->mem
= temp_start
;
377 /* Success, stop navigating through remaining System RAM ranges */
381 static int locate_mem_hole_bottom_up(unsigned long start
, unsigned long end
,
382 struct kexec_buf
*kbuf
)
384 struct kimage
*image
= kbuf
->image
;
385 unsigned long temp_start
, temp_end
;
387 temp_start
= max(start
, kbuf
->buf_min
);
390 temp_start
= ALIGN(temp_start
, kbuf
->buf_align
);
391 temp_end
= temp_start
+ kbuf
->memsz
- 1;
393 if (temp_end
> end
|| temp_end
> kbuf
->buf_max
)
396 * Make sure this does not conflict with any of existing
399 if (kimage_is_destination_range(image
, temp_start
, temp_end
)) {
400 temp_start
= temp_start
+ PAGE_SIZE
;
404 /* We found a suitable memory range */
408 /* If we are here, we found a suitable memory range */
409 kbuf
->mem
= temp_start
;
411 /* Success, stop navigating through remaining System RAM ranges */
415 static int locate_mem_hole_callback(u64 start
, u64 end
, void *arg
)
417 struct kexec_buf
*kbuf
= (struct kexec_buf
*)arg
;
418 unsigned long sz
= end
- start
+ 1;
420 /* Returning 0 will take to next memory range */
421 if (sz
< kbuf
->memsz
)
424 if (end
< kbuf
->buf_min
|| start
> kbuf
->buf_max
)
428 * Allocate memory top down with-in ram range. Otherwise bottom up
432 return locate_mem_hole_top_down(start
, end
, kbuf
);
433 return locate_mem_hole_bottom_up(start
, end
, kbuf
);
437 * arch_kexec_walk_mem - call func(data) on free memory regions
438 * @kbuf: Context info for the search. Also passed to @func.
439 * @func: Function to call for each memory region.
441 * Return: The memory walk will stop when func returns a non-zero value
442 * and that value will be returned. If all free regions are visited without
443 * func returning non-zero, then zero will be returned.
445 int __weak
arch_kexec_walk_mem(struct kexec_buf
*kbuf
,
446 int (*func
)(u64
, u64
, void *))
448 if (kbuf
->image
->type
== KEXEC_TYPE_CRASH
)
449 return walk_iomem_res_desc(crashk_res
.desc
,
450 IORESOURCE_SYSTEM_RAM
| IORESOURCE_BUSY
,
451 crashk_res
.start
, crashk_res
.end
,
454 return walk_system_ram_res(0, ULONG_MAX
, kbuf
, func
);
458 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
459 * @kbuf: Parameters for the memory search.
461 * On success, kbuf->mem will have the start address of the memory region found.
463 * Return: 0 on success, negative errno on error.
465 int kexec_locate_mem_hole(struct kexec_buf
*kbuf
)
469 ret
= arch_kexec_walk_mem(kbuf
, locate_mem_hole_callback
);
471 return ret
== 1 ? 0 : -EADDRNOTAVAIL
;
475 * kexec_add_buffer - place a buffer in a kexec segment
476 * @kbuf: Buffer contents and memory parameters.
478 * This function assumes that kexec_mutex is held.
479 * On successful return, @kbuf->mem will have the physical address of
480 * the buffer in memory.
482 * Return: 0 on success, negative errno on error.
484 int kexec_add_buffer(struct kexec_buf
*kbuf
)
487 struct kexec_segment
*ksegment
;
490 /* Currently adding segment this way is allowed only in file mode */
491 if (!kbuf
->image
->file_mode
)
494 if (kbuf
->image
->nr_segments
>= KEXEC_SEGMENT_MAX
)
498 * Make sure we are not trying to add buffer after allocating
499 * control pages. All segments need to be placed first before
500 * any control pages are allocated. As control page allocation
501 * logic goes through list of segments to make sure there are
502 * no destination overlaps.
504 if (!list_empty(&kbuf
->image
->control_pages
)) {
509 /* Ensure minimum alignment needed for segments. */
510 kbuf
->memsz
= ALIGN(kbuf
->memsz
, PAGE_SIZE
);
511 kbuf
->buf_align
= max(kbuf
->buf_align
, PAGE_SIZE
);
513 /* Walk the RAM ranges and allocate a suitable range for the buffer */
514 ret
= kexec_locate_mem_hole(kbuf
);
518 /* Found a suitable memory range */
519 ksegment
= &kbuf
->image
->segment
[kbuf
->image
->nr_segments
];
520 ksegment
->kbuf
= kbuf
->buffer
;
521 ksegment
->bufsz
= kbuf
->bufsz
;
522 ksegment
->mem
= kbuf
->mem
;
523 ksegment
->memsz
= kbuf
->memsz
;
524 kbuf
->image
->nr_segments
++;
528 /* Calculate and store the digest of segments */
529 static int kexec_calculate_store_digests(struct kimage
*image
)
531 struct crypto_shash
*tfm
;
532 struct shash_desc
*desc
;
533 int ret
= 0, i
, j
, zero_buf_sz
, sha_region_sz
;
534 size_t desc_size
, nullsz
;
537 struct kexec_sha_region
*sha_regions
;
538 struct purgatory_info
*pi
= &image
->purgatory_info
;
540 zero_buf
= __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT
);
541 zero_buf_sz
= PAGE_SIZE
;
543 tfm
= crypto_alloc_shash("sha256", 0, 0);
549 desc_size
= crypto_shash_descsize(tfm
) + sizeof(*desc
);
550 desc
= kzalloc(desc_size
, GFP_KERNEL
);
556 sha_region_sz
= KEXEC_SEGMENT_MAX
* sizeof(struct kexec_sha_region
);
557 sha_regions
= vzalloc(sha_region_sz
);
564 ret
= crypto_shash_init(desc
);
566 goto out_free_sha_regions
;
568 digest
= kzalloc(SHA256_DIGEST_SIZE
, GFP_KERNEL
);
571 goto out_free_sha_regions
;
574 for (j
= i
= 0; i
< image
->nr_segments
; i
++) {
575 struct kexec_segment
*ksegment
;
577 ksegment
= &image
->segment
[i
];
579 * Skip purgatory as it will be modified once we put digest
582 if (ksegment
->kbuf
== pi
->purgatory_buf
)
585 ret
= crypto_shash_update(desc
, ksegment
->kbuf
,
591 * Assume rest of the buffer is filled with zero and
592 * update digest accordingly.
594 nullsz
= ksegment
->memsz
- ksegment
->bufsz
;
596 unsigned long bytes
= nullsz
;
598 if (bytes
> zero_buf_sz
)
600 ret
= crypto_shash_update(desc
, zero_buf
, bytes
);
609 sha_regions
[j
].start
= ksegment
->mem
;
610 sha_regions
[j
].len
= ksegment
->memsz
;
615 ret
= crypto_shash_final(desc
, digest
);
617 goto out_free_digest
;
618 ret
= kexec_purgatory_get_set_symbol(image
, "purgatory_sha_regions",
619 sha_regions
, sha_region_sz
, 0);
621 goto out_free_digest
;
623 ret
= kexec_purgatory_get_set_symbol(image
, "purgatory_sha256_digest",
624 digest
, SHA256_DIGEST_SIZE
, 0);
626 goto out_free_digest
;
631 out_free_sha_regions
:
641 /* Actually load purgatory. Lot of code taken from kexec-tools */
642 static int __kexec_load_purgatory(struct kimage
*image
, unsigned long min
,
643 unsigned long max
, int top_down
)
645 struct purgatory_info
*pi
= &image
->purgatory_info
;
646 unsigned long align
, bss_align
, bss_sz
, bss_pad
;
647 unsigned long entry
, load_addr
, curr_load_addr
, bss_addr
, offset
;
648 unsigned char *buf_addr
, *src
;
649 int i
, ret
= 0, entry_sidx
= -1;
650 const Elf_Shdr
*sechdrs_c
;
651 Elf_Shdr
*sechdrs
= NULL
;
652 struct kexec_buf kbuf
= { .image
= image
, .bufsz
= 0, .buf_align
= 1,
653 .buf_min
= min
, .buf_max
= max
,
654 .top_down
= top_down
};
657 * sechdrs_c points to section headers in purgatory and are read
658 * only. No modifications allowed.
660 sechdrs_c
= (void *)pi
->ehdr
+ pi
->ehdr
->e_shoff
;
663 * We can not modify sechdrs_c[] and its fields. It is read only.
664 * Copy it over to a local copy where one can store some temporary
665 * data and free it at the end. We need to modify ->sh_addr and
666 * ->sh_offset fields to keep track of permanent and temporary
667 * locations of sections.
669 sechdrs
= vzalloc(pi
->ehdr
->e_shnum
* sizeof(Elf_Shdr
));
673 memcpy(sechdrs
, sechdrs_c
, pi
->ehdr
->e_shnum
* sizeof(Elf_Shdr
));
676 * We seem to have multiple copies of sections. First copy is which
677 * is embedded in kernel in read only section. Some of these sections
678 * will be copied to a temporary buffer and relocated. And these
679 * sections will finally be copied to their final destination at
682 * Use ->sh_offset to reflect section address in memory. It will
683 * point to original read only copy if section is not allocatable.
684 * Otherwise it will point to temporary copy which will be relocated.
686 * Use ->sh_addr to contain final address of the section where it
687 * will go during execution time.
689 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
690 if (sechdrs
[i
].sh_type
== SHT_NOBITS
)
693 sechdrs
[i
].sh_offset
= (unsigned long)pi
->ehdr
+
694 sechdrs
[i
].sh_offset
;
698 * Identify entry point section and make entry relative to section
701 entry
= pi
->ehdr
->e_entry
;
702 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
703 if (!(sechdrs
[i
].sh_flags
& SHF_ALLOC
))
706 if (!(sechdrs
[i
].sh_flags
& SHF_EXECINSTR
))
709 /* Make entry section relative */
710 if (sechdrs
[i
].sh_addr
<= pi
->ehdr
->e_entry
&&
711 ((sechdrs
[i
].sh_addr
+ sechdrs
[i
].sh_size
) >
712 pi
->ehdr
->e_entry
)) {
714 entry
-= sechdrs
[i
].sh_addr
;
719 /* Determine how much memory is needed to load relocatable object. */
723 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
724 if (!(sechdrs
[i
].sh_flags
& SHF_ALLOC
))
727 align
= sechdrs
[i
].sh_addralign
;
728 if (sechdrs
[i
].sh_type
!= SHT_NOBITS
) {
729 if (kbuf
.buf_align
< align
)
730 kbuf
.buf_align
= align
;
731 kbuf
.bufsz
= ALIGN(kbuf
.bufsz
, align
);
732 kbuf
.bufsz
+= sechdrs
[i
].sh_size
;
735 if (bss_align
< align
)
737 bss_sz
= ALIGN(bss_sz
, align
);
738 bss_sz
+= sechdrs
[i
].sh_size
;
742 /* Determine the bss padding required to align bss properly */
744 if (kbuf
.bufsz
& (bss_align
- 1))
745 bss_pad
= bss_align
- (kbuf
.bufsz
& (bss_align
- 1));
747 kbuf
.memsz
= kbuf
.bufsz
+ bss_pad
+ bss_sz
;
749 /* Allocate buffer for purgatory */
750 kbuf
.buffer
= vzalloc(kbuf
.bufsz
);
756 if (kbuf
.buf_align
< bss_align
)
757 kbuf
.buf_align
= bss_align
;
759 /* Add buffer to segment list */
760 ret
= kexec_add_buffer(&kbuf
);
763 pi
->purgatory_load_addr
= kbuf
.mem
;
765 /* Load SHF_ALLOC sections */
766 buf_addr
= kbuf
.buffer
;
767 load_addr
= curr_load_addr
= pi
->purgatory_load_addr
;
768 bss_addr
= load_addr
+ kbuf
.bufsz
+ bss_pad
;
770 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
771 if (!(sechdrs
[i
].sh_flags
& SHF_ALLOC
))
774 align
= sechdrs
[i
].sh_addralign
;
775 if (sechdrs
[i
].sh_type
!= SHT_NOBITS
) {
776 curr_load_addr
= ALIGN(curr_load_addr
, align
);
777 offset
= curr_load_addr
- load_addr
;
778 /* We already modifed ->sh_offset to keep src addr */
779 src
= (char *) sechdrs
[i
].sh_offset
;
780 memcpy(buf_addr
+ offset
, src
, sechdrs
[i
].sh_size
);
782 /* Store load address and source address of section */
783 sechdrs
[i
].sh_addr
= curr_load_addr
;
786 * This section got copied to temporary buffer. Update
787 * ->sh_offset accordingly.
789 sechdrs
[i
].sh_offset
= (unsigned long)(buf_addr
+ offset
);
791 /* Advance to the next address */
792 curr_load_addr
+= sechdrs
[i
].sh_size
;
794 bss_addr
= ALIGN(bss_addr
, align
);
795 sechdrs
[i
].sh_addr
= bss_addr
;
796 bss_addr
+= sechdrs
[i
].sh_size
;
800 /* Update entry point based on load address of text section */
802 entry
+= sechdrs
[entry_sidx
].sh_addr
;
804 /* Make kernel jump to purgatory after shutdown */
805 image
->start
= entry
;
807 /* Used later to get/set symbol values */
808 pi
->sechdrs
= sechdrs
;
811 * Used later to identify which section is purgatory and skip it
814 pi
->purgatory_buf
= kbuf
.buffer
;
822 static int kexec_apply_relocations(struct kimage
*image
)
825 struct purgatory_info
*pi
= &image
->purgatory_info
;
826 Elf_Shdr
*sechdrs
= pi
->sechdrs
;
828 /* Apply relocations */
829 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
830 Elf_Shdr
*section
, *symtab
;
832 if (sechdrs
[i
].sh_type
!= SHT_RELA
&&
833 sechdrs
[i
].sh_type
!= SHT_REL
)
837 * For section of type SHT_RELA/SHT_REL,
838 * ->sh_link contains section header index of associated
839 * symbol table. And ->sh_info contains section header
840 * index of section to which relocations apply.
842 if (sechdrs
[i
].sh_info
>= pi
->ehdr
->e_shnum
||
843 sechdrs
[i
].sh_link
>= pi
->ehdr
->e_shnum
)
846 section
= &sechdrs
[sechdrs
[i
].sh_info
];
847 symtab
= &sechdrs
[sechdrs
[i
].sh_link
];
849 if (!(section
->sh_flags
& SHF_ALLOC
))
853 * symtab->sh_link contain section header index of associated
856 if (symtab
->sh_link
>= pi
->ehdr
->e_shnum
)
857 /* Invalid section number? */
861 * Respective architecture needs to provide support for applying
862 * relocations of type SHT_RELA/SHT_REL.
864 if (sechdrs
[i
].sh_type
== SHT_RELA
)
865 ret
= arch_kexec_apply_relocations_add(pi
->ehdr
,
867 else if (sechdrs
[i
].sh_type
== SHT_REL
)
868 ret
= arch_kexec_apply_relocations(pi
->ehdr
,
877 /* Load relocatable purgatory object and relocate it appropriately */
878 int kexec_load_purgatory(struct kimage
*image
, unsigned long min
,
879 unsigned long max
, int top_down
,
880 unsigned long *load_addr
)
882 struct purgatory_info
*pi
= &image
->purgatory_info
;
885 if (kexec_purgatory_size
<= 0)
888 if (kexec_purgatory_size
< sizeof(Elf_Ehdr
))
891 pi
->ehdr
= (Elf_Ehdr
*)kexec_purgatory
;
893 if (memcmp(pi
->ehdr
->e_ident
, ELFMAG
, SELFMAG
) != 0
894 || pi
->ehdr
->e_type
!= ET_REL
895 || !elf_check_arch(pi
->ehdr
)
896 || pi
->ehdr
->e_shentsize
!= sizeof(Elf_Shdr
))
899 if (pi
->ehdr
->e_shoff
>= kexec_purgatory_size
900 || (pi
->ehdr
->e_shnum
* sizeof(Elf_Shdr
) >
901 kexec_purgatory_size
- pi
->ehdr
->e_shoff
))
904 ret
= __kexec_load_purgatory(image
, min
, max
, top_down
);
908 ret
= kexec_apply_relocations(image
);
912 *load_addr
= pi
->purgatory_load_addr
;
918 vfree(pi
->purgatory_buf
);
919 pi
->purgatory_buf
= NULL
;
923 static Elf_Sym
*kexec_purgatory_find_symbol(struct purgatory_info
*pi
,
932 if (!pi
->sechdrs
|| !pi
->ehdr
)
935 sechdrs
= pi
->sechdrs
;
938 for (i
= 0; i
< ehdr
->e_shnum
; i
++) {
939 if (sechdrs
[i
].sh_type
!= SHT_SYMTAB
)
942 if (sechdrs
[i
].sh_link
>= ehdr
->e_shnum
)
943 /* Invalid strtab section number */
945 strtab
= (char *)sechdrs
[sechdrs
[i
].sh_link
].sh_offset
;
946 syms
= (Elf_Sym
*)sechdrs
[i
].sh_offset
;
948 /* Go through symbols for a match */
949 for (k
= 0; k
< sechdrs
[i
].sh_size
/sizeof(Elf_Sym
); k
++) {
950 if (ELF_ST_BIND(syms
[k
].st_info
) != STB_GLOBAL
)
953 if (strcmp(strtab
+ syms
[k
].st_name
, name
) != 0)
956 if (syms
[k
].st_shndx
== SHN_UNDEF
||
957 syms
[k
].st_shndx
>= ehdr
->e_shnum
) {
958 pr_debug("Symbol: %s has bad section index %d.\n",
959 name
, syms
[k
].st_shndx
);
963 /* Found the symbol we are looking for */
971 void *kexec_purgatory_get_symbol_addr(struct kimage
*image
, const char *name
)
973 struct purgatory_info
*pi
= &image
->purgatory_info
;
977 sym
= kexec_purgatory_find_symbol(pi
, name
);
979 return ERR_PTR(-EINVAL
);
981 sechdr
= &pi
->sechdrs
[sym
->st_shndx
];
984 * Returns the address where symbol will finally be loaded after
985 * kexec_load_segment()
987 return (void *)(sechdr
->sh_addr
+ sym
->st_value
);
991 * Get or set value of a symbol. If "get_value" is true, symbol value is
992 * returned in buf otherwise symbol value is set based on value in buf.
994 int kexec_purgatory_get_set_symbol(struct kimage
*image
, const char *name
,
995 void *buf
, unsigned int size
, bool get_value
)
999 struct purgatory_info
*pi
= &image
->purgatory_info
;
1002 sym
= kexec_purgatory_find_symbol(pi
, name
);
1006 if (sym
->st_size
!= size
) {
1007 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1008 name
, (unsigned long)sym
->st_size
, size
);
1012 sechdrs
= pi
->sechdrs
;
1014 if (sechdrs
[sym
->st_shndx
].sh_type
== SHT_NOBITS
) {
1015 pr_err("symbol %s is in a bss section. Cannot %s\n", name
,
1016 get_value
? "get" : "set");
1020 sym_buf
= (unsigned char *)sechdrs
[sym
->st_shndx
].sh_offset
+
1024 memcpy((void *)buf
, sym_buf
, size
);
1026 memcpy((void *)sym_buf
, buf
, size
);