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 <crypto/hash.h>
23 #include <crypto/sha.h>
24 #include <linux/syscalls.h>
25 #include <linux/vmalloc.h>
26 #include "kexec_internal.h"
29 * Declare these symbols weak so that if architecture provides a purgatory,
30 * these will be overridden.
32 char __weak kexec_purgatory
[0];
33 size_t __weak kexec_purgatory_size
= 0;
35 static int kexec_calculate_store_digests(struct kimage
*image
);
37 /* Architectures can provide this probe function */
38 int __weak
arch_kexec_kernel_image_probe(struct kimage
*image
, void *buf
,
39 unsigned long buf_len
)
44 void * __weak
arch_kexec_kernel_image_load(struct kimage
*image
)
46 return ERR_PTR(-ENOEXEC
);
49 int __weak
arch_kimage_file_post_load_cleanup(struct kimage
*image
)
54 #ifdef CONFIG_KEXEC_VERIFY_SIG
55 int __weak
arch_kexec_kernel_verify_sig(struct kimage
*image
, void *buf
,
56 unsigned long buf_len
)
62 /* Apply relocations of type RELA */
64 arch_kexec_apply_relocations_add(const Elf_Ehdr
*ehdr
, Elf_Shdr
*sechdrs
,
67 pr_err("RELA relocation unsupported.\n");
71 /* Apply relocations of type REL */
73 arch_kexec_apply_relocations(const Elf_Ehdr
*ehdr
, Elf_Shdr
*sechdrs
,
76 pr_err("REL relocation unsupported.\n");
81 * Free up memory used by kernel, initrd, and command line. This is temporary
82 * memory allocation which is not needed any more after these buffers have
83 * been loaded into separate segments and have been copied elsewhere.
85 void kimage_file_post_load_cleanup(struct kimage
*image
)
87 struct purgatory_info
*pi
= &image
->purgatory_info
;
89 vfree(image
->kernel_buf
);
90 image
->kernel_buf
= NULL
;
92 vfree(image
->initrd_buf
);
93 image
->initrd_buf
= NULL
;
95 kfree(image
->cmdline_buf
);
96 image
->cmdline_buf
= NULL
;
98 vfree(pi
->purgatory_buf
);
99 pi
->purgatory_buf
= NULL
;
104 /* See if architecture has anything to cleanup post load */
105 arch_kimage_file_post_load_cleanup(image
);
108 * Above call should have called into bootloader to free up
109 * any data stored in kimage->image_loader_data. It should
110 * be ok now to free it up.
112 kfree(image
->image_loader_data
);
113 image
->image_loader_data
= NULL
;
117 * In file mode list of segments is prepared by kernel. Copy relevant
118 * data from user space, do error checking, prepare segment list
121 kimage_file_prepare_segments(struct kimage
*image
, int kernel_fd
, int initrd_fd
,
122 const char __user
*cmdline_ptr
,
123 unsigned long cmdline_len
, unsigned flags
)
129 ret
= kernel_read_file_from_fd(kernel_fd
, &image
->kernel_buf
,
130 &size
, INT_MAX
, READING_KEXEC_IMAGE
);
133 image
->kernel_buf_len
= size
;
135 /* Call arch image probe handlers */
136 ret
= arch_kexec_kernel_image_probe(image
, image
->kernel_buf
,
137 image
->kernel_buf_len
);
141 #ifdef CONFIG_KEXEC_VERIFY_SIG
142 ret
= arch_kexec_kernel_verify_sig(image
, image
->kernel_buf
,
143 image
->kernel_buf_len
);
145 pr_debug("kernel signature verification failed.\n");
148 pr_debug("kernel signature verification successful.\n");
150 /* It is possible that there no initramfs is being loaded */
151 if (!(flags
& KEXEC_FILE_NO_INITRAMFS
)) {
152 ret
= kernel_read_file_from_fd(initrd_fd
, &image
->initrd_buf
,
154 READING_KEXEC_INITRAMFS
);
157 image
->initrd_buf_len
= size
;
161 image
->cmdline_buf
= kzalloc(cmdline_len
, GFP_KERNEL
);
162 if (!image
->cmdline_buf
) {
167 ret
= copy_from_user(image
->cmdline_buf
, cmdline_ptr
,
174 image
->cmdline_buf_len
= cmdline_len
;
176 /* command line should be a string with last byte null */
177 if (image
->cmdline_buf
[cmdline_len
- 1] != '\0') {
183 /* Call arch image load handlers */
184 ldata
= arch_kexec_kernel_image_load(image
);
187 ret
= PTR_ERR(ldata
);
191 image
->image_loader_data
= ldata
;
193 /* In case of error, free up all allocated memory in this function */
195 kimage_file_post_load_cleanup(image
);
200 kimage_file_alloc_init(struct kimage
**rimage
, int kernel_fd
,
201 int initrd_fd
, const char __user
*cmdline_ptr
,
202 unsigned long cmdline_len
, unsigned long flags
)
205 struct kimage
*image
;
206 bool kexec_on_panic
= flags
& KEXEC_FILE_ON_CRASH
;
208 image
= do_kimage_alloc_init();
212 image
->file_mode
= 1;
214 if (kexec_on_panic
) {
215 /* Enable special crash kernel control page alloc policy. */
216 image
->control_page
= crashk_res
.start
;
217 image
->type
= KEXEC_TYPE_CRASH
;
220 ret
= kimage_file_prepare_segments(image
, kernel_fd
, initrd_fd
,
221 cmdline_ptr
, cmdline_len
, flags
);
225 ret
= sanity_check_segment_list(image
);
227 goto out_free_post_load_bufs
;
230 image
->control_code_page
= kimage_alloc_control_pages(image
,
231 get_order(KEXEC_CONTROL_PAGE_SIZE
));
232 if (!image
->control_code_page
) {
233 pr_err("Could not allocate control_code_buffer\n");
234 goto out_free_post_load_bufs
;
237 if (!kexec_on_panic
) {
238 image
->swap_page
= kimage_alloc_control_pages(image
, 0);
239 if (!image
->swap_page
) {
240 pr_err("Could not allocate swap buffer\n");
241 goto out_free_control_pages
;
247 out_free_control_pages
:
248 kimage_free_page_list(&image
->control_pages
);
249 out_free_post_load_bufs
:
250 kimage_file_post_load_cleanup(image
);
256 SYSCALL_DEFINE5(kexec_file_load
, int, kernel_fd
, int, initrd_fd
,
257 unsigned long, cmdline_len
, const char __user
*, cmdline_ptr
,
258 unsigned long, flags
)
261 struct kimage
**dest_image
, *image
;
263 /* We only trust the superuser with rebooting the system. */
264 if (!capable(CAP_SYS_BOOT
) || kexec_load_disabled
)
267 /* Make sure we have a legal set of flags */
268 if (flags
!= (flags
& KEXEC_FILE_FLAGS
))
273 if (!mutex_trylock(&kexec_mutex
))
276 dest_image
= &kexec_image
;
277 if (flags
& KEXEC_FILE_ON_CRASH
) {
278 dest_image
= &kexec_crash_image
;
279 if (kexec_crash_image
)
280 arch_kexec_unprotect_crashkres();
283 if (flags
& KEXEC_FILE_UNLOAD
)
287 * In case of crash, new kernel gets loaded in reserved region. It is
288 * same memory where old crash kernel might be loaded. Free any
289 * current crash dump kernel before we corrupt it.
291 if (flags
& KEXEC_FILE_ON_CRASH
)
292 kimage_free(xchg(&kexec_crash_image
, NULL
));
294 ret
= kimage_file_alloc_init(&image
, kernel_fd
, initrd_fd
, cmdline_ptr
,
299 ret
= machine_kexec_prepare(image
);
303 ret
= kexec_calculate_store_digests(image
);
307 for (i
= 0; i
< image
->nr_segments
; i
++) {
308 struct kexec_segment
*ksegment
;
310 ksegment
= &image
->segment
[i
];
311 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
312 i
, ksegment
->buf
, ksegment
->bufsz
, ksegment
->mem
,
315 ret
= kimage_load_segment(image
, &image
->segment
[i
]);
320 kimage_terminate(image
);
323 * Free up any temporary buffers allocated which are not needed
324 * after image has been loaded
326 kimage_file_post_load_cleanup(image
);
328 image
= xchg(dest_image
, image
);
330 if ((flags
& KEXEC_FILE_ON_CRASH
) && kexec_crash_image
)
331 arch_kexec_protect_crashkres();
333 mutex_unlock(&kexec_mutex
);
338 static int locate_mem_hole_top_down(unsigned long start
, unsigned long end
,
339 struct kexec_buf
*kbuf
)
341 struct kimage
*image
= kbuf
->image
;
342 unsigned long temp_start
, temp_end
;
344 temp_end
= min(end
, kbuf
->buf_max
);
345 temp_start
= temp_end
- kbuf
->memsz
;
348 /* align down start */
349 temp_start
= temp_start
& (~(kbuf
->buf_align
- 1));
351 if (temp_start
< start
|| temp_start
< kbuf
->buf_min
)
354 temp_end
= temp_start
+ kbuf
->memsz
- 1;
357 * Make sure this does not conflict with any of existing
360 if (kimage_is_destination_range(image
, temp_start
, temp_end
)) {
361 temp_start
= temp_start
- PAGE_SIZE
;
365 /* We found a suitable memory range */
369 /* If we are here, we found a suitable memory range */
370 kbuf
->mem
= temp_start
;
372 /* Success, stop navigating through remaining System RAM ranges */
376 static int locate_mem_hole_bottom_up(unsigned long start
, unsigned long end
,
377 struct kexec_buf
*kbuf
)
379 struct kimage
*image
= kbuf
->image
;
380 unsigned long temp_start
, temp_end
;
382 temp_start
= max(start
, kbuf
->buf_min
);
385 temp_start
= ALIGN(temp_start
, kbuf
->buf_align
);
386 temp_end
= temp_start
+ kbuf
->memsz
- 1;
388 if (temp_end
> end
|| temp_end
> kbuf
->buf_max
)
391 * Make sure this does not conflict with any of existing
394 if (kimage_is_destination_range(image
, temp_start
, temp_end
)) {
395 temp_start
= temp_start
+ PAGE_SIZE
;
399 /* We found a suitable memory range */
403 /* If we are here, we found a suitable memory range */
404 kbuf
->mem
= temp_start
;
406 /* Success, stop navigating through remaining System RAM ranges */
410 static int locate_mem_hole_callback(u64 start
, u64 end
, void *arg
)
412 struct kexec_buf
*kbuf
= (struct kexec_buf
*)arg
;
413 unsigned long sz
= end
- start
+ 1;
415 /* Returning 0 will take to next memory range */
416 if (sz
< kbuf
->memsz
)
419 if (end
< kbuf
->buf_min
|| start
> kbuf
->buf_max
)
423 * Allocate memory top down with-in ram range. Otherwise bottom up
427 return locate_mem_hole_top_down(start
, end
, kbuf
);
428 return locate_mem_hole_bottom_up(start
, end
, kbuf
);
432 * arch_kexec_walk_mem - call func(data) on free memory regions
433 * @kbuf: Context info for the search. Also passed to @func.
434 * @func: Function to call for each memory region.
436 * Return: The memory walk will stop when func returns a non-zero value
437 * and that value will be returned. If all free regions are visited without
438 * func returning non-zero, then zero will be returned.
440 int __weak
arch_kexec_walk_mem(struct kexec_buf
*kbuf
,
441 int (*func
)(u64
, u64
, void *))
443 if (kbuf
->image
->type
== KEXEC_TYPE_CRASH
)
444 return walk_iomem_res_desc(crashk_res
.desc
,
445 IORESOURCE_SYSTEM_RAM
| IORESOURCE_BUSY
,
446 crashk_res
.start
, crashk_res
.end
,
449 return walk_system_ram_res(0, ULONG_MAX
, kbuf
, func
);
453 * Helper function for placing a buffer in a kexec segment. This assumes
454 * that kexec_mutex is held.
456 int kexec_add_buffer(struct kimage
*image
, char *buffer
, unsigned long bufsz
,
457 unsigned long memsz
, unsigned long buf_align
,
458 unsigned long buf_min
, unsigned long buf_max
,
459 bool top_down
, unsigned long *load_addr
)
462 struct kexec_segment
*ksegment
;
463 struct kexec_buf buf
, *kbuf
;
466 /* Currently adding segment this way is allowed only in file mode */
467 if (!image
->file_mode
)
470 if (image
->nr_segments
>= KEXEC_SEGMENT_MAX
)
474 * Make sure we are not trying to add buffer after allocating
475 * control pages. All segments need to be placed first before
476 * any control pages are allocated. As control page allocation
477 * logic goes through list of segments to make sure there are
478 * no destination overlaps.
480 if (!list_empty(&image
->control_pages
)) {
485 memset(&buf
, 0, sizeof(struct kexec_buf
));
488 kbuf
->buffer
= buffer
;
491 kbuf
->memsz
= ALIGN(memsz
, PAGE_SIZE
);
492 kbuf
->buf_align
= max(buf_align
, PAGE_SIZE
);
493 kbuf
->buf_min
= buf_min
;
494 kbuf
->buf_max
= buf_max
;
495 kbuf
->top_down
= top_down
;
497 /* Walk the RAM ranges and allocate a suitable range for the buffer */
498 ret
= arch_kexec_walk_mem(kbuf
, locate_mem_hole_callback
);
500 /* A suitable memory range could not be found for buffer */
501 return -EADDRNOTAVAIL
;
504 /* Found a suitable memory range */
505 ksegment
= &image
->segment
[image
->nr_segments
];
506 ksegment
->kbuf
= kbuf
->buffer
;
507 ksegment
->bufsz
= kbuf
->bufsz
;
508 ksegment
->mem
= kbuf
->mem
;
509 ksegment
->memsz
= kbuf
->memsz
;
510 image
->nr_segments
++;
511 *load_addr
= ksegment
->mem
;
515 /* Calculate and store the digest of segments */
516 static int kexec_calculate_store_digests(struct kimage
*image
)
518 struct crypto_shash
*tfm
;
519 struct shash_desc
*desc
;
520 int ret
= 0, i
, j
, zero_buf_sz
, sha_region_sz
;
521 size_t desc_size
, nullsz
;
524 struct kexec_sha_region
*sha_regions
;
525 struct purgatory_info
*pi
= &image
->purgatory_info
;
527 zero_buf
= __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT
);
528 zero_buf_sz
= PAGE_SIZE
;
530 tfm
= crypto_alloc_shash("sha256", 0, 0);
536 desc_size
= crypto_shash_descsize(tfm
) + sizeof(*desc
);
537 desc
= kzalloc(desc_size
, GFP_KERNEL
);
543 sha_region_sz
= KEXEC_SEGMENT_MAX
* sizeof(struct kexec_sha_region
);
544 sha_regions
= vzalloc(sha_region_sz
);
551 ret
= crypto_shash_init(desc
);
553 goto out_free_sha_regions
;
555 digest
= kzalloc(SHA256_DIGEST_SIZE
, GFP_KERNEL
);
558 goto out_free_sha_regions
;
561 for (j
= i
= 0; i
< image
->nr_segments
; i
++) {
562 struct kexec_segment
*ksegment
;
564 ksegment
= &image
->segment
[i
];
566 * Skip purgatory as it will be modified once we put digest
569 if (ksegment
->kbuf
== pi
->purgatory_buf
)
572 ret
= crypto_shash_update(desc
, ksegment
->kbuf
,
578 * Assume rest of the buffer is filled with zero and
579 * update digest accordingly.
581 nullsz
= ksegment
->memsz
- ksegment
->bufsz
;
583 unsigned long bytes
= nullsz
;
585 if (bytes
> zero_buf_sz
)
587 ret
= crypto_shash_update(desc
, zero_buf
, bytes
);
596 sha_regions
[j
].start
= ksegment
->mem
;
597 sha_regions
[j
].len
= ksegment
->memsz
;
602 ret
= crypto_shash_final(desc
, digest
);
604 goto out_free_digest
;
605 ret
= kexec_purgatory_get_set_symbol(image
, "sha_regions",
606 sha_regions
, sha_region_sz
, 0);
608 goto out_free_digest
;
610 ret
= kexec_purgatory_get_set_symbol(image
, "sha256_digest",
611 digest
, SHA256_DIGEST_SIZE
, 0);
613 goto out_free_digest
;
618 out_free_sha_regions
:
628 /* Actually load purgatory. Lot of code taken from kexec-tools */
629 static int __kexec_load_purgatory(struct kimage
*image
, unsigned long min
,
630 unsigned long max
, int top_down
)
632 struct purgatory_info
*pi
= &image
->purgatory_info
;
633 unsigned long align
, buf_align
, bss_align
, buf_sz
, bss_sz
, bss_pad
;
634 unsigned long memsz
, entry
, load_addr
, curr_load_addr
, bss_addr
, offset
;
635 unsigned char *buf_addr
, *src
;
636 int i
, ret
= 0, entry_sidx
= -1;
637 const Elf_Shdr
*sechdrs_c
;
638 Elf_Shdr
*sechdrs
= NULL
;
639 void *purgatory_buf
= NULL
;
642 * sechdrs_c points to section headers in purgatory and are read
643 * only. No modifications allowed.
645 sechdrs_c
= (void *)pi
->ehdr
+ pi
->ehdr
->e_shoff
;
648 * We can not modify sechdrs_c[] and its fields. It is read only.
649 * Copy it over to a local copy where one can store some temporary
650 * data and free it at the end. We need to modify ->sh_addr and
651 * ->sh_offset fields to keep track of permanent and temporary
652 * locations of sections.
654 sechdrs
= vzalloc(pi
->ehdr
->e_shnum
* sizeof(Elf_Shdr
));
658 memcpy(sechdrs
, sechdrs_c
, pi
->ehdr
->e_shnum
* sizeof(Elf_Shdr
));
661 * We seem to have multiple copies of sections. First copy is which
662 * is embedded in kernel in read only section. Some of these sections
663 * will be copied to a temporary buffer and relocated. And these
664 * sections will finally be copied to their final destination at
667 * Use ->sh_offset to reflect section address in memory. It will
668 * point to original read only copy if section is not allocatable.
669 * Otherwise it will point to temporary copy which will be relocated.
671 * Use ->sh_addr to contain final address of the section where it
672 * will go during execution time.
674 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
675 if (sechdrs
[i
].sh_type
== SHT_NOBITS
)
678 sechdrs
[i
].sh_offset
= (unsigned long)pi
->ehdr
+
679 sechdrs
[i
].sh_offset
;
683 * Identify entry point section and make entry relative to section
686 entry
= pi
->ehdr
->e_entry
;
687 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
688 if (!(sechdrs
[i
].sh_flags
& SHF_ALLOC
))
691 if (!(sechdrs
[i
].sh_flags
& SHF_EXECINSTR
))
694 /* Make entry section relative */
695 if (sechdrs
[i
].sh_addr
<= pi
->ehdr
->e_entry
&&
696 ((sechdrs
[i
].sh_addr
+ sechdrs
[i
].sh_size
) >
697 pi
->ehdr
->e_entry
)) {
699 entry
-= sechdrs
[i
].sh_addr
;
704 /* Determine how much memory is needed to load relocatable object. */
710 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
711 if (!(sechdrs
[i
].sh_flags
& SHF_ALLOC
))
714 align
= sechdrs
[i
].sh_addralign
;
715 if (sechdrs
[i
].sh_type
!= SHT_NOBITS
) {
716 if (buf_align
< align
)
718 buf_sz
= ALIGN(buf_sz
, align
);
719 buf_sz
+= sechdrs
[i
].sh_size
;
722 if (bss_align
< align
)
724 bss_sz
= ALIGN(bss_sz
, align
);
725 bss_sz
+= sechdrs
[i
].sh_size
;
729 /* Determine the bss padding required to align bss properly */
731 if (buf_sz
& (bss_align
- 1))
732 bss_pad
= bss_align
- (buf_sz
& (bss_align
- 1));
734 memsz
= buf_sz
+ bss_pad
+ bss_sz
;
736 /* Allocate buffer for purgatory */
737 purgatory_buf
= vzalloc(buf_sz
);
738 if (!purgatory_buf
) {
743 if (buf_align
< bss_align
)
744 buf_align
= bss_align
;
746 /* Add buffer to segment list */
747 ret
= kexec_add_buffer(image
, purgatory_buf
, buf_sz
, memsz
,
748 buf_align
, min
, max
, top_down
,
749 &pi
->purgatory_load_addr
);
753 /* Load SHF_ALLOC sections */
754 buf_addr
= purgatory_buf
;
755 load_addr
= curr_load_addr
= pi
->purgatory_load_addr
;
756 bss_addr
= load_addr
+ buf_sz
+ bss_pad
;
758 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
759 if (!(sechdrs
[i
].sh_flags
& SHF_ALLOC
))
762 align
= sechdrs
[i
].sh_addralign
;
763 if (sechdrs
[i
].sh_type
!= SHT_NOBITS
) {
764 curr_load_addr
= ALIGN(curr_load_addr
, align
);
765 offset
= curr_load_addr
- load_addr
;
766 /* We already modifed ->sh_offset to keep src addr */
767 src
= (char *) sechdrs
[i
].sh_offset
;
768 memcpy(buf_addr
+ offset
, src
, sechdrs
[i
].sh_size
);
770 /* Store load address and source address of section */
771 sechdrs
[i
].sh_addr
= curr_load_addr
;
774 * This section got copied to temporary buffer. Update
775 * ->sh_offset accordingly.
777 sechdrs
[i
].sh_offset
= (unsigned long)(buf_addr
+ offset
);
779 /* Advance to the next address */
780 curr_load_addr
+= sechdrs
[i
].sh_size
;
782 bss_addr
= ALIGN(bss_addr
, align
);
783 sechdrs
[i
].sh_addr
= bss_addr
;
784 bss_addr
+= sechdrs
[i
].sh_size
;
788 /* Update entry point based on load address of text section */
790 entry
+= sechdrs
[entry_sidx
].sh_addr
;
792 /* Make kernel jump to purgatory after shutdown */
793 image
->start
= entry
;
795 /* Used later to get/set symbol values */
796 pi
->sechdrs
= sechdrs
;
799 * Used later to identify which section is purgatory and skip it
802 pi
->purgatory_buf
= purgatory_buf
;
806 vfree(purgatory_buf
);
810 static int kexec_apply_relocations(struct kimage
*image
)
813 struct purgatory_info
*pi
= &image
->purgatory_info
;
814 Elf_Shdr
*sechdrs
= pi
->sechdrs
;
816 /* Apply relocations */
817 for (i
= 0; i
< pi
->ehdr
->e_shnum
; i
++) {
818 Elf_Shdr
*section
, *symtab
;
820 if (sechdrs
[i
].sh_type
!= SHT_RELA
&&
821 sechdrs
[i
].sh_type
!= SHT_REL
)
825 * For section of type SHT_RELA/SHT_REL,
826 * ->sh_link contains section header index of associated
827 * symbol table. And ->sh_info contains section header
828 * index of section to which relocations apply.
830 if (sechdrs
[i
].sh_info
>= pi
->ehdr
->e_shnum
||
831 sechdrs
[i
].sh_link
>= pi
->ehdr
->e_shnum
)
834 section
= &sechdrs
[sechdrs
[i
].sh_info
];
835 symtab
= &sechdrs
[sechdrs
[i
].sh_link
];
837 if (!(section
->sh_flags
& SHF_ALLOC
))
841 * symtab->sh_link contain section header index of associated
844 if (symtab
->sh_link
>= pi
->ehdr
->e_shnum
)
845 /* Invalid section number? */
849 * Respective architecture needs to provide support for applying
850 * relocations of type SHT_RELA/SHT_REL.
852 if (sechdrs
[i
].sh_type
== SHT_RELA
)
853 ret
= arch_kexec_apply_relocations_add(pi
->ehdr
,
855 else if (sechdrs
[i
].sh_type
== SHT_REL
)
856 ret
= arch_kexec_apply_relocations(pi
->ehdr
,
865 /* Load relocatable purgatory object and relocate it appropriately */
866 int kexec_load_purgatory(struct kimage
*image
, unsigned long min
,
867 unsigned long max
, int top_down
,
868 unsigned long *load_addr
)
870 struct purgatory_info
*pi
= &image
->purgatory_info
;
873 if (kexec_purgatory_size
<= 0)
876 if (kexec_purgatory_size
< sizeof(Elf_Ehdr
))
879 pi
->ehdr
= (Elf_Ehdr
*)kexec_purgatory
;
881 if (memcmp(pi
->ehdr
->e_ident
, ELFMAG
, SELFMAG
) != 0
882 || pi
->ehdr
->e_type
!= ET_REL
883 || !elf_check_arch(pi
->ehdr
)
884 || pi
->ehdr
->e_shentsize
!= sizeof(Elf_Shdr
))
887 if (pi
->ehdr
->e_shoff
>= kexec_purgatory_size
888 || (pi
->ehdr
->e_shnum
* sizeof(Elf_Shdr
) >
889 kexec_purgatory_size
- pi
->ehdr
->e_shoff
))
892 ret
= __kexec_load_purgatory(image
, min
, max
, top_down
);
896 ret
= kexec_apply_relocations(image
);
900 *load_addr
= pi
->purgatory_load_addr
;
906 vfree(pi
->purgatory_buf
);
907 pi
->purgatory_buf
= NULL
;
911 static Elf_Sym
*kexec_purgatory_find_symbol(struct purgatory_info
*pi
,
920 if (!pi
->sechdrs
|| !pi
->ehdr
)
923 sechdrs
= pi
->sechdrs
;
926 for (i
= 0; i
< ehdr
->e_shnum
; i
++) {
927 if (sechdrs
[i
].sh_type
!= SHT_SYMTAB
)
930 if (sechdrs
[i
].sh_link
>= ehdr
->e_shnum
)
931 /* Invalid strtab section number */
933 strtab
= (char *)sechdrs
[sechdrs
[i
].sh_link
].sh_offset
;
934 syms
= (Elf_Sym
*)sechdrs
[i
].sh_offset
;
936 /* Go through symbols for a match */
937 for (k
= 0; k
< sechdrs
[i
].sh_size
/sizeof(Elf_Sym
); k
++) {
938 if (ELF_ST_BIND(syms
[k
].st_info
) != STB_GLOBAL
)
941 if (strcmp(strtab
+ syms
[k
].st_name
, name
) != 0)
944 if (syms
[k
].st_shndx
== SHN_UNDEF
||
945 syms
[k
].st_shndx
>= ehdr
->e_shnum
) {
946 pr_debug("Symbol: %s has bad section index %d.\n",
947 name
, syms
[k
].st_shndx
);
951 /* Found the symbol we are looking for */
959 void *kexec_purgatory_get_symbol_addr(struct kimage
*image
, const char *name
)
961 struct purgatory_info
*pi
= &image
->purgatory_info
;
965 sym
= kexec_purgatory_find_symbol(pi
, name
);
967 return ERR_PTR(-EINVAL
);
969 sechdr
= &pi
->sechdrs
[sym
->st_shndx
];
972 * Returns the address where symbol will finally be loaded after
973 * kexec_load_segment()
975 return (void *)(sechdr
->sh_addr
+ sym
->st_value
);
979 * Get or set value of a symbol. If "get_value" is true, symbol value is
980 * returned in buf otherwise symbol value is set based on value in buf.
982 int kexec_purgatory_get_set_symbol(struct kimage
*image
, const char *name
,
983 void *buf
, unsigned int size
, bool get_value
)
987 struct purgatory_info
*pi
= &image
->purgatory_info
;
990 sym
= kexec_purgatory_find_symbol(pi
, name
);
994 if (sym
->st_size
!= size
) {
995 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
996 name
, (unsigned long)sym
->st_size
, size
);
1000 sechdrs
= pi
->sechdrs
;
1002 if (sechdrs
[sym
->st_shndx
].sh_type
== SHT_NOBITS
) {
1003 pr_err("symbol %s is in a bss section. Cannot %s\n", name
,
1004 get_value
? "get" : "set");
1008 sym_buf
= (unsigned char *)sechdrs
[sym
->st_shndx
].sh_offset
+
1012 memcpy((void *)buf
, sym_buf
, size
);
1014 memcpy((void *)sym_buf
, buf
, size
);