projects/linux·blob v3.19 · refs

2770 lines · 67.8 KiB

1/*
2 * kexec.c - kexec system call
3 * Copyright (C) 2002-2004 Eric Biederman <[email protected]>
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
8
9#define pr_fmt(fmt) "kexec: " fmt
10
11#include <linux/capability.h>
12#include <linux/mm.h>
13#include <linux/file.h>
14#include <linux/slab.h>
15#include <linux/fs.h>
16#include <linux/kexec.h>
17#include <linux/mutex.h>
18#include <linux/list.h>
19#include <linux/highmem.h>
20#include <linux/syscalls.h>
21#include <linux/reboot.h>
22#include <linux/ioport.h>
23#include <linux/hardirq.h>
24#include <linux/elf.h>
25#include <linux/elfcore.h>
26#include <linux/utsname.h>
27#include <linux/numa.h>
28#include <linux/suspend.h>
29#include <linux/device.h>
30#include <linux/freezer.h>
31#include <linux/pm.h>
32#include <linux/cpu.h>
33#include <linux/console.h>
34#include <linux/vmalloc.h>
35#include <linux/swap.h>
36#include <linux/syscore_ops.h>
37#include <linux/compiler.h>
38#include <linux/hugetlb.h>
39
40#include <asm/page.h>
41#include <asm/uaccess.h>
42#include <asm/io.h>
43#include <asm/sections.h>
44
45#include <crypto/hash.h>
46#include <crypto/sha.h>
47
48/* Per cpu memory for storing cpu states in case of system crash. */
49note_buf_t __percpu *crash_notes;
50
51/* vmcoreinfo stuff */
52static unsigned char vmcoreinfo_data[VMCOREINFO_BYTES];
53u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
54size_t vmcoreinfo_size;
55size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
56
57/* Flag to indicate we are going to kexec a new kernel */
58bool kexec_in_progress = false;
59
60/*
61 * Declare these symbols weak so that if architecture provides a purgatory,
62 * these will be overridden.
63 */
64char __weak kexec_purgatory[0];
65size_t __weak kexec_purgatory_size = 0;
66
67#ifdef CONFIG_KEXEC_FILE
68static int kexec_calculate_store_digests(struct kimage *image);
69#endif
70
71/* Location of the reserved area for the crash kernel */
72struct resource crashk_res = {
73 .name = "Crash kernel",
74 .start = 0,
75 .end = 0,
76 .flags = IORESOURCE_BUSY | IORESOURCE_MEM
77};
78struct resource crashk_low_res = {
79 .name = "Crash kernel",
80 .start = 0,
81 .end = 0,
82 .flags = IORESOURCE_BUSY | IORESOURCE_MEM
83};
84
85int kexec_should_crash(struct task_struct *p)
86{
87 if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
88 return 1;
89 return 0;
90}
91
92/*
93 * When kexec transitions to the new kernel there is a one-to-one
94 * mapping between physical and virtual addresses. On processors
95 * where you can disable the MMU this is trivial, and easy. For
96 * others it is still a simple predictable page table to setup.
97 *
98 * In that environment kexec copies the new kernel to its final
99 * resting place. This means I can only support memory whose
100 * physical address can fit in an unsigned long. In particular
101 * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
102 * If the assembly stub has more restrictive requirements
103 * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
104 * defined more restrictively in <asm/kexec.h>.
105 *
106 * The code for the transition from the current kernel to the
107 * the new kernel is placed in the control_code_buffer, whose size
108 * is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single
109 * page of memory is necessary, but some architectures require more.
110 * Because this memory must be identity mapped in the transition from
111 * virtual to physical addresses it must live in the range
112 * 0 - TASK_SIZE, as only the user space mappings are arbitrarily
113 * modifiable.
114 *
115 * The assembly stub in the control code buffer is passed a linked list
116 * of descriptor pages detailing the source pages of the new kernel,
117 * and the destination addresses of those source pages. As this data
118 * structure is not used in the context of the current OS, it must
119 * be self-contained.
120 *
121 * The code has been made to work with highmem pages and will use a
122 * destination page in its final resting place (if it happens
123 * to allocate it). The end product of this is that most of the
124 * physical address space, and most of RAM can be used.
125 *
126 * Future directions include:
127 * - allocating a page table with the control code buffer identity
128 * mapped, to simplify machine_kexec and make kexec_on_panic more
129 * reliable.
130 */
131
132/*
133 * KIMAGE_NO_DEST is an impossible destination address..., for
134 * allocating pages whose destination address we do not care about.
135 */
136#define KIMAGE_NO_DEST (-1UL)
137
138static int kimage_is_destination_range(struct kimage *image,
139 unsigned long start, unsigned long end);
140static struct page *kimage_alloc_page(struct kimage *image,
141 gfp_t gfp_mask,
142 unsigned long dest);
143
144static int copy_user_segment_list(struct kimage *image,
145 unsigned long nr_segments,
146 struct kexec_segment __user *segments)
147{
148 int ret;
149 size_t segment_bytes;
150
151 /* Read in the segments */
152 image->nr_segments = nr_segments;
153 segment_bytes = nr_segments * sizeof(*segments);
154 ret = copy_from_user(image->segment, segments, segment_bytes);
155 if (ret)
156 ret = -EFAULT;
157
158 return ret;
159}
160
161static int sanity_check_segment_list(struct kimage *image)
162{
163 int result, i;
164 unsigned long nr_segments = image->nr_segments;
165
166 /*
167 * Verify we have good destination addresses. The caller is
168 * responsible for making certain we don't attempt to load
169 * the new image into invalid or reserved areas of RAM. This
170 * just verifies it is an address we can use.
171 *
172 * Since the kernel does everything in page size chunks ensure
173 * the destination addresses are page aligned. Too many
174 * special cases crop of when we don't do this. The most
175 * insidious is getting overlapping destination addresses
176 * simply because addresses are changed to page size
177 * granularity.
178 */
179 result = -EADDRNOTAVAIL;
180 for (i = 0; i < nr_segments; i++) {
181 unsigned long mstart, mend;
182
183 mstart = image->segment[i].mem;
184 mend = mstart + image->segment[i].memsz;
185 if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
186 return result;
187 if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
188 return result;
189 }
190
191 /* Verify our destination addresses do not overlap.
192 * If we alloed overlapping destination addresses
193 * through very weird things can happen with no
194 * easy explanation as one segment stops on another.
195 */
196 result = -EINVAL;
197 for (i = 0; i < nr_segments; i++) {
198 unsigned long mstart, mend;
199 unsigned long j;
200
201 mstart = image->segment[i].mem;
202 mend = mstart + image->segment[i].memsz;
203 for (j = 0; j < i; j++) {
204 unsigned long pstart, pend;
205 pstart = image->segment[j].mem;
206 pend = pstart + image->segment[j].memsz;
207 /* Do the segments overlap ? */
208 if ((mend > pstart) && (mstart < pend))
209 return result;
210 }
211 }
212
213 /* Ensure our buffer sizes are strictly less than
214 * our memory sizes. This should always be the case,
215 * and it is easier to check up front than to be surprised
216 * later on.
217 */
218 result = -EINVAL;
219 for (i = 0; i < nr_segments; i++) {
220 if (image->segment[i].bufsz > image->segment[i].memsz)
221 return result;
222 }
223
224 /*
225 * Verify we have good destination addresses. Normally
226 * the caller is responsible for making certain we don't
227 * attempt to load the new image into invalid or reserved
228 * areas of RAM. But crash kernels are preloaded into a
229 * reserved area of ram. We must ensure the addresses
230 * are in the reserved area otherwise preloading the
231 * kernel could corrupt things.
232 */
233
234 if (image->type == KEXEC_TYPE_CRASH) {
235 result = -EADDRNOTAVAIL;
236 for (i = 0; i < nr_segments; i++) {
237 unsigned long mstart, mend;
238
239 mstart = image->segment[i].mem;
240 mend = mstart + image->segment[i].memsz - 1;
241 /* Ensure we are within the crash kernel limits */
242 if ((mstart < crashk_res.start) ||
243 (mend > crashk_res.end))
244 return result;
245 }
246 }
247
248 return 0;
249}
250
251static struct kimage *do_kimage_alloc_init(void)
252{
253 struct kimage *image;
254
255 /* Allocate a controlling structure */
256 image = kzalloc(sizeof(*image), GFP_KERNEL);
257 if (!image)
258 return NULL;
259
260 image->head = 0;
261 image->entry = &image->head;
262 image->last_entry = &image->head;
263 image->control_page = ~0; /* By default this does not apply */
264 image->type = KEXEC_TYPE_DEFAULT;
265
266 /* Initialize the list of control pages */
267 INIT_LIST_HEAD(&image->control_pages);
268
269 /* Initialize the list of destination pages */
270 INIT_LIST_HEAD(&image->dest_pages);
271
272 /* Initialize the list of unusable pages */
273 INIT_LIST_HEAD(&image->unusable_pages);
274
275 return image;
276}
277
278static void kimage_free_page_list(struct list_head *list);
279
280static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
281 unsigned long nr_segments,
282 struct kexec_segment __user *segments,
283 unsigned long flags)
284{
285 int ret;
286 struct kimage *image;
287 bool kexec_on_panic = flags & KEXEC_ON_CRASH;
288
289 if (kexec_on_panic) {
290 /* Verify we have a valid entry point */
291 if ((entry < crashk_res.start) || (entry > crashk_res.end))
292 return -EADDRNOTAVAIL;
293 }
294
295 /* Allocate and initialize a controlling structure */
296 image = do_kimage_alloc_init();
297 if (!image)
298 return -ENOMEM;
299
300 image->start = entry;
301
302 ret = copy_user_segment_list(image, nr_segments, segments);
303 if (ret)
304 goto out_free_image;
305
306 ret = sanity_check_segment_list(image);
307 if (ret)
308 goto out_free_image;
309
310 /* Enable the special crash kernel control page allocation policy. */
311 if (kexec_on_panic) {
312 image->control_page = crashk_res.start;
313 image->type = KEXEC_TYPE_CRASH;
314 }
315
316 /*
317 * Find a location for the control code buffer, and add it
318 * the vector of segments so that it's pages will also be
319 * counted as destination pages.
320 */
321 ret = -ENOMEM;
322 image->control_code_page = kimage_alloc_control_pages(image,
323 get_order(KEXEC_CONTROL_PAGE_SIZE));
324 if (!image->control_code_page) {
325 pr_err("Could not allocate control_code_buffer\n");
326 goto out_free_image;
327 }
328
329 if (!kexec_on_panic) {
330 image->swap_page = kimage_alloc_control_pages(image, 0);
331 if (!image->swap_page) {
332 pr_err("Could not allocate swap buffer\n");
333 goto out_free_control_pages;
334 }
335 }
336
337 *rimage = image;
338 return 0;
339out_free_control_pages:
340 kimage_free_page_list(&image->control_pages);
341out_free_image:
342 kfree(image);
343 return ret;
344}
345
346#ifdef CONFIG_KEXEC_FILE
347static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
348{
349 struct fd f = fdget(fd);
350 int ret;
351 struct kstat stat;
352 loff_t pos;
353 ssize_t bytes = 0;
354
355 if (!f.file)
356 return -EBADF;
357
358 ret = vfs_getattr(&f.file->f_path, &stat);
359 if (ret)
360 goto out;
361
362 if (stat.size > INT_MAX) {
363 ret = -EFBIG;
364 goto out;
365 }
366
367 /* Don't hand 0 to vmalloc, it whines. */
368 if (stat.size == 0) {
369 ret = -EINVAL;
370 goto out;
371 }
372
373 *buf = vmalloc(stat.size);
374 if (!*buf) {
375 ret = -ENOMEM;
376 goto out;
377 }
378
379 pos = 0;
380 while (pos < stat.size) {
381 bytes = kernel_read(f.file, pos, (char *)(*buf) + pos,
382 stat.size - pos);
383 if (bytes < 0) {
384 vfree(*buf);
385 ret = bytes;
386 goto out;
387 }
388
389 if (bytes == 0)
390 break;
391 pos += bytes;
392 }
393
394 if (pos != stat.size) {
395 ret = -EBADF;
396 vfree(*buf);
397 goto out;
398 }
399
400 *buf_len = pos;
401out:
402 fdput(f);
403 return ret;
404}
405
406/* Architectures can provide this probe function */
407int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
408 unsigned long buf_len)
409{
410 return -ENOEXEC;
411}
412
413void * __weak arch_kexec_kernel_image_load(struct kimage *image)
414{
415 return ERR_PTR(-ENOEXEC);
416}
417
418void __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
419{
420}
421
422int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
423 unsigned long buf_len)
424{
425 return -EKEYREJECTED;
426}
427
428/* Apply relocations of type RELA */
429int __weak
430arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
431 unsigned int relsec)
432{
433 pr_err("RELA relocation unsupported.\n");
434 return -ENOEXEC;
435}
436
437/* Apply relocations of type REL */
438int __weak
439arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
440 unsigned int relsec)
441{
442 pr_err("REL relocation unsupported.\n");
443 return -ENOEXEC;
444}
445
446/*
447 * Free up memory used by kernel, initrd, and comand line. This is temporary
448 * memory allocation which is not needed any more after these buffers have
449 * been loaded into separate segments and have been copied elsewhere.
450 */
451static void kimage_file_post_load_cleanup(struct kimage *image)
452{
453 struct purgatory_info *pi = &image->purgatory_info;
454
455 vfree(image->kernel_buf);
456 image->kernel_buf = NULL;
457
458 vfree(image->initrd_buf);
459 image->initrd_buf = NULL;
460
461 kfree(image->cmdline_buf);
462 image->cmdline_buf = NULL;
463
464 vfree(pi->purgatory_buf);
465 pi->purgatory_buf = NULL;
466
467 vfree(pi->sechdrs);
468 pi->sechdrs = NULL;
469
470 /* See if architecture has anything to cleanup post load */
471 arch_kimage_file_post_load_cleanup(image);
472
473 /*
474 * Above call should have called into bootloader to free up
475 * any data stored in kimage->image_loader_data. It should
476 * be ok now to free it up.
477 */
478 kfree(image->image_loader_data);
479 image->image_loader_data = NULL;
480}
481
482/*
483 * In file mode list of segments is prepared by kernel. Copy relevant
484 * data from user space, do error checking, prepare segment list
485 */
486static int
487kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
488 const char __user *cmdline_ptr,
489 unsigned long cmdline_len, unsigned flags)
490{
491 int ret = 0;
492 void *ldata;
493
494 ret = copy_file_from_fd(kernel_fd, &image->kernel_buf,
495 &image->kernel_buf_len);
496 if (ret)
497 return ret;
498
499 /* Call arch image probe handlers */
500 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
501 image->kernel_buf_len);
502
503 if (ret)
504 goto out;
505
506#ifdef CONFIG_KEXEC_VERIFY_SIG
507 ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
508 image->kernel_buf_len);
509 if (ret) {
510 pr_debug("kernel signature verification failed.\n");
511 goto out;
512 }
513 pr_debug("kernel signature verification successful.\n");
514#endif
515 /* It is possible that there no initramfs is being loaded */
516 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
517 ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,
518 &image->initrd_buf_len);
519 if (ret)
520 goto out;
521 }
522
523 if (cmdline_len) {
524 image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL);
525 if (!image->cmdline_buf) {
526 ret = -ENOMEM;
527 goto out;
528 }
529
530 ret = copy_from_user(image->cmdline_buf, cmdline_ptr,
531 cmdline_len);
532 if (ret) {
533 ret = -EFAULT;
534 goto out;
535 }
536
537 image->cmdline_buf_len = cmdline_len;
538
539 /* command line should be a string with last byte null */
540 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
541 ret = -EINVAL;
542 goto out;
543 }
544 }
545
546 /* Call arch image load handlers */
547 ldata = arch_kexec_kernel_image_load(image);
548
549 if (IS_ERR(ldata)) {
550 ret = PTR_ERR(ldata);
551 goto out;
552 }
553
554 image->image_loader_data = ldata;
555out:
556 /* In case of error, free up all allocated memory in this function */
557 if (ret)
558 kimage_file_post_load_cleanup(image);
559 return ret;
560}
561
562static int
563kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
564 int initrd_fd, const char __user *cmdline_ptr,
565 unsigned long cmdline_len, unsigned long flags)
566{
567 int ret;
568 struct kimage *image;
569 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
570
571 image = do_kimage_alloc_init();
572 if (!image)
573 return -ENOMEM;
574
575 image->file_mode = 1;
576
577 if (kexec_on_panic) {
578 /* Enable special crash kernel control page alloc policy. */
579 image->control_page = crashk_res.start;
580 image->type = KEXEC_TYPE_CRASH;
581 }
582
583 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
584 cmdline_ptr, cmdline_len, flags);
585 if (ret)
586 goto out_free_image;
587
588 ret = sanity_check_segment_list(image);
589 if (ret)
590 goto out_free_post_load_bufs;
591
592 ret = -ENOMEM;
593 image->control_code_page = kimage_alloc_control_pages(image,
594 get_order(KEXEC_CONTROL_PAGE_SIZE));
595 if (!image->control_code_page) {
596 pr_err("Could not allocate control_code_buffer\n");
597 goto out_free_post_load_bufs;
598 }
599
600 if (!kexec_on_panic) {
601 image->swap_page = kimage_alloc_control_pages(image, 0);
602 if (!image->swap_page) {
603 pr_err("Could not allocate swap buffer\n");
604 goto out_free_control_pages;
605 }
606 }
607
608 *rimage = image;
609 return 0;
610out_free_control_pages:
611 kimage_free_page_list(&image->control_pages);
612out_free_post_load_bufs:
613 kimage_file_post_load_cleanup(image);
614out_free_image:
615 kfree(image);
616 return ret;
617}
618#else /* CONFIG_KEXEC_FILE */
619static inline void kimage_file_post_load_cleanup(struct kimage *image) { }
620#endif /* CONFIG_KEXEC_FILE */
621
622static int kimage_is_destination_range(struct kimage *image,
623 unsigned long start,
624 unsigned long end)
625{
626 unsigned long i;
627
628 for (i = 0; i < image->nr_segments; i++) {
629 unsigned long mstart, mend;
630
631 mstart = image->segment[i].mem;
632 mend = mstart + image->segment[i].memsz;
633 if ((end > mstart) && (start < mend))
634 return 1;
635 }
636
637 return 0;
638}
639
640static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
641{
642 struct page *pages;
643
644 pages = alloc_pages(gfp_mask, order);
645 if (pages) {
646 unsigned int count, i;
647 pages->mapping = NULL;
648 set_page_private(pages, order);
649 count = 1 << order;
650 for (i = 0; i < count; i++)
651 SetPageReserved(pages + i);
652 }
653
654 return pages;
655}
656
657static void kimage_free_pages(struct page *page)
658{
659 unsigned int order, count, i;
660
661 order = page_private(page);
662 count = 1 << order;
663 for (i = 0; i < count; i++)
664 ClearPageReserved(page + i);
665 __free_pages(page, order);
666}
667
668static void kimage_free_page_list(struct list_head *list)
669{
670 struct list_head *pos, *next;
671
672 list_for_each_safe(pos, next, list) {
673 struct page *page;
674
675 page = list_entry(pos, struct page, lru);
676 list_del(&page->lru);
677 kimage_free_pages(page);
678 }
679}
680
681static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
682 unsigned int order)
683{
684 /* Control pages are special, they are the intermediaries
685 * that are needed while we copy the rest of the pages
686 * to their final resting place. As such they must
687 * not conflict with either the destination addresses
688 * or memory the kernel is already using.
689 *
690 * The only case where we really need more than one of
691 * these are for architectures where we cannot disable
692 * the MMU and must instead generate an identity mapped
693 * page table for all of the memory.
694 *
695 * At worst this runs in O(N) of the image size.
696 */
697 struct list_head extra_pages;
698 struct page *pages;
699 unsigned int count;
700
701 count = 1 << order;
702 INIT_LIST_HEAD(&extra_pages);
703
704 /* Loop while I can allocate a page and the page allocated
705 * is a destination page.
706 */
707 do {
708 unsigned long pfn, epfn, addr, eaddr;
709
710 pages = kimage_alloc_pages(GFP_KERNEL, order);
711 if (!pages)
712 break;
713 pfn = page_to_pfn(pages);
714 epfn = pfn + count;
715 addr = pfn << PAGE_SHIFT;
716 eaddr = epfn << PAGE_SHIFT;
717 if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
718 kimage_is_destination_range(image, addr, eaddr)) {
719 list_add(&pages->lru, &extra_pages);
720 pages = NULL;
721 }
722 } while (!pages);
723
724 if (pages) {
725 /* Remember the allocated page... */
726 list_add(&pages->lru, &image->control_pages);
727
728 /* Because the page is already in it's destination
729 * location we will never allocate another page at
730 * that address. Therefore kimage_alloc_pages
731 * will not return it (again) and we don't need
732 * to give it an entry in image->segment[].
733 */
734 }
735 /* Deal with the destination pages I have inadvertently allocated.
736 *
737 * Ideally I would convert multi-page allocations into single
738 * page allocations, and add everything to image->dest_pages.
739 *
740 * For now it is simpler to just free the pages.
741 */
742 kimage_free_page_list(&extra_pages);
743
744 return pages;
745}
746
747static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
748 unsigned int order)
749{
750 /* Control pages are special, they are the intermediaries
751 * that are needed while we copy the rest of the pages
752 * to their final resting place. As such they must
753 * not conflict with either the destination addresses
754 * or memory the kernel is already using.
755 *
756 * Control pages are also the only pags we must allocate
757 * when loading a crash kernel. All of the other pages
758 * are specified by the segments and we just memcpy
759 * into them directly.
760 *
761 * The only case where we really need more than one of
762 * these are for architectures where we cannot disable
763 * the MMU and must instead generate an identity mapped
764 * page table for all of the memory.
765 *
766 * Given the low demand this implements a very simple
767 * allocator that finds the first hole of the appropriate
768 * size in the reserved memory region, and allocates all
769 * of the memory up to and including the hole.
770 */
771 unsigned long hole_start, hole_end, size;
772 struct page *pages;
773
774 pages = NULL;
775 size = (1 << order) << PAGE_SHIFT;
776 hole_start = (image->control_page + (size - 1)) & ~(size - 1);
777 hole_end = hole_start + size - 1;
778 while (hole_end <= crashk_res.end) {
779 unsigned long i;
780
781 if (hole_end > KEXEC_CRASH_CONTROL_MEMORY_LIMIT)
782 break;
783 /* See if I overlap any of the segments */
784 for (i = 0; i < image->nr_segments; i++) {
785 unsigned long mstart, mend;
786
787 mstart = image->segment[i].mem;
788 mend = mstart + image->segment[i].memsz - 1;
789 if ((hole_end >= mstart) && (hole_start <= mend)) {
790 /* Advance the hole to the end of the segment */
791 hole_start = (mend + (size - 1)) & ~(size - 1);
792 hole_end = hole_start + size - 1;
793 break;
794 }
795 }
796 /* If I don't overlap any segments I have found my hole! */
797 if (i == image->nr_segments) {
798 pages = pfn_to_page(hole_start >> PAGE_SHIFT);
799 break;
800 }
801 }
802 if (pages)
803 image->control_page = hole_end;
804
805 return pages;
806}
807
808
809struct page *kimage_alloc_control_pages(struct kimage *image,
810 unsigned int order)
811{
812 struct page *pages = NULL;
813
814 switch (image->type) {
815 case KEXEC_TYPE_DEFAULT:
816 pages = kimage_alloc_normal_control_pages(image, order);
817 break;
818 case KEXEC_TYPE_CRASH:
819 pages = kimage_alloc_crash_control_pages(image, order);
820 break;
821 }
822
823 return pages;
824}
825
826static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
827{
828 if (*image->entry != 0)
829 image->entry++;
830
831 if (image->entry == image->last_entry) {
832 kimage_entry_t *ind_page;
833 struct page *page;
834
835 page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
836 if (!page)
837 return -ENOMEM;
838
839 ind_page = page_address(page);
840 *image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
841 image->entry = ind_page;
842 image->last_entry = ind_page +
843 ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
844 }
845 *image->entry = entry;
846 image->entry++;
847 *image->entry = 0;
848
849 return 0;
850}
851
852static int kimage_set_destination(struct kimage *image,
853 unsigned long destination)
854{
855 int result;
856
857 destination &= PAGE_MASK;
858 result = kimage_add_entry(image, destination | IND_DESTINATION);
859 if (result == 0)
860 image->destination = destination;
861
862 return result;
863}
864
865
866static int kimage_add_page(struct kimage *image, unsigned long page)
867{
868 int result;
869
870 page &= PAGE_MASK;
871 result = kimage_add_entry(image, page | IND_SOURCE);
872 if (result == 0)
873 image->destination += PAGE_SIZE;
874
875 return result;
876}
877
878
879static void kimage_free_extra_pages(struct kimage *image)
880{
881 /* Walk through and free any extra destination pages I may have */
882 kimage_free_page_list(&image->dest_pages);
883
884 /* Walk through and free any unusable pages I have cached */
885 kimage_free_page_list(&image->unusable_pages);
886
887}
888static void kimage_terminate(struct kimage *image)
889{
890 if (*image->entry != 0)
891 image->entry++;
892
893 *image->entry = IND_DONE;
894}
895
896#define for_each_kimage_entry(image, ptr, entry) \
897 for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
898 ptr = (entry & IND_INDIRECTION) ? \
899 phys_to_virt((entry & PAGE_MASK)) : ptr + 1)
900
901static void kimage_free_entry(kimage_entry_t entry)
902{
903 struct page *page;
904
905 page = pfn_to_page(entry >> PAGE_SHIFT);
906 kimage_free_pages(page);
907}
908
909static void kimage_free(struct kimage *image)
910{
911 kimage_entry_t *ptr, entry;
912 kimage_entry_t ind = 0;
913
914 if (!image)
915 return;
916
917 kimage_free_extra_pages(image);
918 for_each_kimage_entry(image, ptr, entry) {
919 if (entry & IND_INDIRECTION) {
920 /* Free the previous indirection page */
921 if (ind & IND_INDIRECTION)
922 kimage_free_entry(ind);
923 /* Save this indirection page until we are
924 * done with it.
925 */
926 ind = entry;
927 } else if (entry & IND_SOURCE)
928 kimage_free_entry(entry);
929 }
930 /* Free the final indirection page */
931 if (ind & IND_INDIRECTION)
932 kimage_free_entry(ind);
933
934 /* Handle any machine specific cleanup */
935 machine_kexec_cleanup(image);
936
937 /* Free the kexec control pages... */
938 kimage_free_page_list(&image->control_pages);
939
940 /*
941 * Free up any temporary buffers allocated. This might hit if
942 * error occurred much later after buffer allocation.
943 */
944 if (image->file_mode)
945 kimage_file_post_load_cleanup(image);
946
947 kfree(image);
948}
949
950static kimage_entry_t *kimage_dst_used(struct kimage *image,
951 unsigned long page)
952{
953 kimage_entry_t *ptr, entry;
954 unsigned long destination = 0;
955
956 for_each_kimage_entry(image, ptr, entry) {
957 if (entry & IND_DESTINATION)
958 destination = entry & PAGE_MASK;
959 else if (entry & IND_SOURCE) {
960 if (page == destination)
961 return ptr;
962 destination += PAGE_SIZE;
963 }
964 }
965
966 return NULL;
967}
968
969static struct page *kimage_alloc_page(struct kimage *image,
970 gfp_t gfp_mask,
971 unsigned long destination)
972{
973 /*
974 * Here we implement safeguards to ensure that a source page
975 * is not copied to its destination page before the data on
976 * the destination page is no longer useful.
977 *
978 * To do this we maintain the invariant that a source page is
979 * either its own destination page, or it is not a
980 * destination page at all.
981 *
982 * That is slightly stronger than required, but the proof
983 * that no problems will not occur is trivial, and the
984 * implementation is simply to verify.
985 *
986 * When allocating all pages normally this algorithm will run
987 * in O(N) time, but in the worst case it will run in O(N^2)
988 * time. If the runtime is a problem the data structures can
989 * be fixed.
990 */
991 struct page *page;
992 unsigned long addr;
993
994 /*
995 * Walk through the list of destination pages, and see if I
996 * have a match.
997 */
998 list_for_each_entry(page, &image->dest_pages, lru) {
999 addr = page_to_pfn(page) << PAGE_SHIFT;
1000 if (addr == destination) {
1001 list_del(&page->lru);
1002 return page;
1003 }
1004 }
1005 page = NULL;
1006 while (1) {
1007 kimage_entry_t *old;
1008
1009 /* Allocate a page, if we run out of memory give up */
1010 page = kimage_alloc_pages(gfp_mask, 0);
1011 if (!page)
1012 return NULL;
1013 /* If the page cannot be used file it away */
1014 if (page_to_pfn(page) >
1015 (KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
1016 list_add(&page->lru, &image->unusable_pages);
1017 continue;
1018 }
1019 addr = page_to_pfn(page) << PAGE_SHIFT;
1020
1021 /* If it is the destination page we want use it */
1022 if (addr == destination)
1023 break;
1024
1025 /* If the page is not a destination page use it */
1026 if (!kimage_is_destination_range(image, addr,
1027 addr + PAGE_SIZE))
1028 break;
1029
1030 /*
1031 * I know that the page is someones destination page.
1032 * See if there is already a source page for this
1033 * destination page. And if so swap the source pages.
1034 */
1035 old = kimage_dst_used(image, addr);
1036 if (old) {
1037 /* If so move it */
1038 unsigned long old_addr;
1039 struct page *old_page;
1040
1041 old_addr = *old & PAGE_MASK;
1042 old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
1043 copy_highpage(page, old_page);
1044 *old = addr | (*old & ~PAGE_MASK);
1045
1046 /* The old page I have found cannot be a
1047 * destination page, so return it if it's
1048 * gfp_flags honor the ones passed in.
1049 */
1050 if (!(gfp_mask & __GFP_HIGHMEM) &&
1051 PageHighMem(old_page)) {
1052 kimage_free_pages(old_page);
1053 continue;
1054 }
1055 addr = old_addr;
1056 page = old_page;
1057 break;
1058 } else {
1059 /* Place the page on the destination list I
1060 * will use it later.
1061 */
1062 list_add(&page->lru, &image->dest_pages);
1063 }
1064 }
1065
1066 return page;
1067}
1068
1069static int kimage_load_normal_segment(struct kimage *image,
1070 struct kexec_segment *segment)
1071{
1072 unsigned long maddr;
1073 size_t ubytes, mbytes;
1074 int result;
1075 unsigned char __user *buf = NULL;
1076 unsigned char *kbuf = NULL;
1077
1078 result = 0;
1079 if (image->file_mode)
1080 kbuf = segment->kbuf;
1081 else
1082 buf = segment->buf;
1083 ubytes = segment->bufsz;
1084 mbytes = segment->memsz;
1085 maddr = segment->mem;
1086
1087 result = kimage_set_destination(image, maddr);
1088 if (result < 0)
1089 goto out;
1090
1091 while (mbytes) {
1092 struct page *page;
1093 char *ptr;
1094 size_t uchunk, mchunk;
1095
1096 page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
1097 if (!page) {
1098 result = -ENOMEM;
1099 goto out;
1100 }
1101 result = kimage_add_page(image, page_to_pfn(page)
1102 << PAGE_SHIFT);
1103 if (result < 0)
1104 goto out;
1105
1106 ptr = kmap(page);
1107 /* Start with a clear page */
1108 clear_page(ptr);
1109 ptr += maddr & ~PAGE_MASK;
1110 mchunk = min_t(size_t, mbytes,
1111 PAGE_SIZE - (maddr & ~PAGE_MASK));
1112 uchunk = min(ubytes, mchunk);
1113
1114 /* For file based kexec, source pages are in kernel memory */
1115 if (image->file_mode)
1116 memcpy(ptr, kbuf, uchunk);
1117 else
1118 result = copy_from_user(ptr, buf, uchunk);
1119 kunmap(page);
1120 if (result) {
1121 result = -EFAULT;
1122 goto out;
1123 }
1124 ubytes -= uchunk;
1125 maddr += mchunk;
1126 if (image->file_mode)
1127 kbuf += mchunk;
1128 else
1129 buf += mchunk;
1130 mbytes -= mchunk;
1131 }
1132out:
1133 return result;
1134}
1135
1136static int kimage_load_crash_segment(struct kimage *image,
1137 struct kexec_segment *segment)
1138{
1139 /* For crash dumps kernels we simply copy the data from
1140 * user space to it's destination.
1141 * We do things a page at a time for the sake of kmap.
1142 */
1143 unsigned long maddr;
1144 size_t ubytes, mbytes;
1145 int result;
1146 unsigned char __user *buf = NULL;
1147 unsigned char *kbuf = NULL;
1148
1149 result = 0;
1150 if (image->file_mode)
1151 kbuf = segment->kbuf;
1152 else
1153 buf = segment->buf;
1154 ubytes = segment->bufsz;
1155 mbytes = segment->memsz;
1156 maddr = segment->mem;
1157 while (mbytes) {
1158 struct page *page;
1159 char *ptr;
1160 size_t uchunk, mchunk;
1161
1162 page = pfn_to_page(maddr >> PAGE_SHIFT);
1163 if (!page) {
1164 result = -ENOMEM;
1165 goto out;
1166 }
1167 ptr = kmap(page);
1168 ptr += maddr & ~PAGE_MASK;
1169 mchunk = min_t(size_t, mbytes,
1170 PAGE_SIZE - (maddr & ~PAGE_MASK));
1171 uchunk = min(ubytes, mchunk);
1172 if (mchunk > uchunk) {
1173 /* Zero the trailing part of the page */
1174 memset(ptr + uchunk, 0, mchunk - uchunk);
1175 }
1176
1177 /* For file based kexec, source pages are in kernel memory */
1178 if (image->file_mode)
1179 memcpy(ptr, kbuf, uchunk);
1180 else
1181 result = copy_from_user(ptr, buf, uchunk);
1182 kexec_flush_icache_page(page);
1183 kunmap(page);
1184 if (result) {
1185 result = -EFAULT;
1186 goto out;
1187 }
1188 ubytes -= uchunk;
1189 maddr += mchunk;
1190 if (image->file_mode)
1191 kbuf += mchunk;
1192 else
1193 buf += mchunk;
1194 mbytes -= mchunk;
1195 }
1196out:
1197 return result;
1198}
1199
1200static int kimage_load_segment(struct kimage *image,
1201 struct kexec_segment *segment)
1202{
1203 int result = -ENOMEM;
1204
1205 switch (image->type) {
1206 case KEXEC_TYPE_DEFAULT:
1207 result = kimage_load_normal_segment(image, segment);
1208 break;
1209 case KEXEC_TYPE_CRASH:
1210 result = kimage_load_crash_segment(image, segment);
1211 break;
1212 }
1213
1214 return result;
1215}
1216
1217/*
1218 * Exec Kernel system call: for obvious reasons only root may call it.
1219 *
1220 * This call breaks up into three pieces.
1221 * - A generic part which loads the new kernel from the current
1222 * address space, and very carefully places the data in the
1223 * allocated pages.
1224 *
1225 * - A generic part that interacts with the kernel and tells all of
1226 * the devices to shut down. Preventing on-going dmas, and placing
1227 * the devices in a consistent state so a later kernel can
1228 * reinitialize them.
1229 *
1230 * - A machine specific part that includes the syscall number
1231 * and then copies the image to it's final destination. And
1232 * jumps into the image at entry.
1233 *
1234 * kexec does not sync, or unmount filesystems so if you need
1235 * that to happen you need to do that yourself.
1236 */
1237struct kimage *kexec_image;
1238struct kimage *kexec_crash_image;
1239int kexec_load_disabled;
1240
1241static DEFINE_MUTEX(kexec_mutex);
1242
1243SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
1244 struct kexec_segment __user *, segments, unsigned long, flags)
1245{
1246 struct kimage **dest_image, *image;
1247 int result;
1248
1249 /* We only trust the superuser with rebooting the system. */
1250 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
1251 return -EPERM;
1252
1253 /*
1254 * Verify we have a legal set of flags
1255 * This leaves us room for future extensions.
1256 */
1257 if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
1258 return -EINVAL;
1259
1260 /* Verify we are on the appropriate architecture */
1261 if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
1262 ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
1263 return -EINVAL;
1264
1265 /* Put an artificial cap on the number
1266 * of segments passed to kexec_load.
1267 */
1268 if (nr_segments > KEXEC_SEGMENT_MAX)
1269 return -EINVAL;
1270
1271 image = NULL;
1272 result = 0;
1273
1274 /* Because we write directly to the reserved memory
1275 * region when loading crash kernels we need a mutex here to
1276 * prevent multiple crash kernels from attempting to load
1277 * simultaneously, and to prevent a crash kernel from loading
1278 * over the top of a in use crash kernel.
1279 *
1280 * KISS: always take the mutex.
1281 */
1282 if (!mutex_trylock(&kexec_mutex))
1283 return -EBUSY;
1284
1285 dest_image = &kexec_image;
1286 if (flags & KEXEC_ON_CRASH)
1287 dest_image = &kexec_crash_image;
1288 if (nr_segments > 0) {
1289 unsigned long i;
1290
1291 /* Loading another kernel to reboot into */
1292 if ((flags & KEXEC_ON_CRASH) == 0)
1293 result = kimage_alloc_init(&image, entry, nr_segments,
1294 segments, flags);
1295 /* Loading another kernel to switch to if this one crashes */
1296 else if (flags & KEXEC_ON_CRASH) {
1297 /* Free any current crash dump kernel before
1298 * we corrupt it.
1299 */
1300 kimage_free(xchg(&kexec_crash_image, NULL));
1301 result = kimage_alloc_init(&image, entry, nr_segments,
1302 segments, flags);
1303 crash_map_reserved_pages();
1304 }
1305 if (result)
1306 goto out;
1307
1308 if (flags & KEXEC_PRESERVE_CONTEXT)
1309 image->preserve_context = 1;
1310 result = machine_kexec_prepare(image);
1311 if (result)
1312 goto out;
1313
1314 for (i = 0; i < nr_segments; i++) {
1315 result = kimage_load_segment(image, &image->segment[i]);
1316 if (result)
1317 goto out;
1318 }
1319 kimage_terminate(image);
1320 if (flags & KEXEC_ON_CRASH)
1321 crash_unmap_reserved_pages();
1322 }
1323 /* Install the new kernel, and Uninstall the old */
1324 image = xchg(dest_image, image);
1325
1326out:
1327 mutex_unlock(&kexec_mutex);
1328 kimage_free(image);
1329
1330 return result;
1331}
1332
1333/*
1334 * Add and remove page tables for crashkernel memory
1335 *
1336 * Provide an empty default implementation here -- architecture
1337 * code may override this
1338 */
1339void __weak crash_map_reserved_pages(void)
1340{}
1341
1342void __weak crash_unmap_reserved_pages(void)
1343{}
1344
1345#ifdef CONFIG_COMPAT
1346COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
1347 compat_ulong_t, nr_segments,
1348 struct compat_kexec_segment __user *, segments,
1349 compat_ulong_t, flags)
1350{
1351 struct compat_kexec_segment in;
1352 struct kexec_segment out, __user *ksegments;
1353 unsigned long i, result;
1354
1355 /* Don't allow clients that don't understand the native
1356 * architecture to do anything.
1357 */
1358 if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
1359 return -EINVAL;
1360
1361 if (nr_segments > KEXEC_SEGMENT_MAX)
1362 return -EINVAL;
1363
1364 ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
1365 for (i = 0; i < nr_segments; i++) {
1366 result = copy_from_user(&in, &segments[i], sizeof(in));
1367 if (result)
1368 return -EFAULT;
1369
1370 out.buf = compat_ptr(in.buf);
1371 out.bufsz = in.bufsz;
1372 out.mem = in.mem;
1373 out.memsz = in.memsz;
1374
1375 result = copy_to_user(&ksegments[i], &out, sizeof(out));
1376 if (result)
1377 return -EFAULT;
1378 }
1379
1380 return sys_kexec_load(entry, nr_segments, ksegments, flags);
1381}
1382#endif
1383
1384#ifdef CONFIG_KEXEC_FILE
1385SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
1386 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
1387 unsigned long, flags)
1388{
1389 int ret = 0, i;
1390 struct kimage **dest_image, *image;
1391
1392 /* We only trust the superuser with rebooting the system. */
1393 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
1394 return -EPERM;
1395
1396 /* Make sure we have a legal set of flags */
1397 if (flags != (flags & KEXEC_FILE_FLAGS))
1398 return -EINVAL;
1399
1400 image = NULL;
1401
1402 if (!mutex_trylock(&kexec_mutex))
1403 return -EBUSY;
1404
1405 dest_image = &kexec_image;
1406 if (flags & KEXEC_FILE_ON_CRASH)
1407 dest_image = &kexec_crash_image;
1408
1409 if (flags & KEXEC_FILE_UNLOAD)
1410 goto exchange;
1411
1412 /*
1413 * In case of crash, new kernel gets loaded in reserved region. It is
1414 * same memory where old crash kernel might be loaded. Free any
1415 * current crash dump kernel before we corrupt it.
1416 */
1417 if (flags & KEXEC_FILE_ON_CRASH)
1418 kimage_free(xchg(&kexec_crash_image, NULL));
1419
1420 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
1421 cmdline_len, flags);
1422 if (ret)
1423 goto out;
1424
1425 ret = machine_kexec_prepare(image);
1426 if (ret)
1427 goto out;
1428
1429 ret = kexec_calculate_store_digests(image);
1430 if (ret)
1431 goto out;
1432
1433 for (i = 0; i < image->nr_segments; i++) {
1434 struct kexec_segment *ksegment;
1435
1436 ksegment = &image->segment[i];
1437 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
1438 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
1439 ksegment->memsz);
1440
1441 ret = kimage_load_segment(image, &image->segment[i]);
1442 if (ret)
1443 goto out;
1444 }
1445
1446 kimage_terminate(image);
1447
1448 /*
1449 * Free up any temporary buffers allocated which are not needed
1450 * after image has been loaded
1451 */
1452 kimage_file_post_load_cleanup(image);
1453exchange:
1454 image = xchg(dest_image, image);
1455out:
1456 mutex_unlock(&kexec_mutex);
1457 kimage_free(image);
1458 return ret;
1459}
1460
1461#endif /* CONFIG_KEXEC_FILE */
1462
1463void crash_kexec(struct pt_regs *regs)
1464{
1465 /* Take the kexec_mutex here to prevent sys_kexec_load
1466 * running on one cpu from replacing the crash kernel
1467 * we are using after a panic on a different cpu.
1468 *
1469 * If the crash kernel was not located in a fixed area
1470 * of memory the xchg(&kexec_crash_image) would be
1471 * sufficient. But since I reuse the memory...
1472 */
1473 if (mutex_trylock(&kexec_mutex)) {
1474 if (kexec_crash_image) {
1475 struct pt_regs fixed_regs;
1476
1477 crash_setup_regs(&fixed_regs, regs);
1478 crash_save_vmcoreinfo();
1479 machine_crash_shutdown(&fixed_regs);
1480 machine_kexec(kexec_crash_image);
1481 }
1482 mutex_unlock(&kexec_mutex);
1483 }
1484}
1485
1486size_t crash_get_memory_size(void)
1487{
1488 size_t size = 0;
1489 mutex_lock(&kexec_mutex);
1490 if (crashk_res.end != crashk_res.start)
1491 size = resource_size(&crashk_res);
1492 mutex_unlock(&kexec_mutex);
1493 return size;
1494}
1495
1496void __weak crash_free_reserved_phys_range(unsigned long begin,
1497 unsigned long end)
1498{
1499 unsigned long addr;
1500
1501 for (addr = begin; addr < end; addr += PAGE_SIZE)
1502 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
1503}
1504
1505int crash_shrink_memory(unsigned long new_size)
1506{
1507 int ret = 0;
1508 unsigned long start, end;
1509 unsigned long old_size;
1510 struct resource *ram_res;
1511
1512 mutex_lock(&kexec_mutex);
1513
1514 if (kexec_crash_image) {
1515 ret = -ENOENT;
1516 goto unlock;
1517 }
1518 start = crashk_res.start;
1519 end = crashk_res.end;
1520 old_size = (end == 0) ? 0 : end - start + 1;
1521 if (new_size >= old_size) {
1522 ret = (new_size == old_size) ? 0 : -EINVAL;
1523 goto unlock;
1524 }
1525
1526 ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
1527 if (!ram_res) {
1528 ret = -ENOMEM;
1529 goto unlock;
1530 }
1531
1532 start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
1533 end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
1534
1535 crash_map_reserved_pages();
1536 crash_free_reserved_phys_range(end, crashk_res.end);
1537
1538 if ((start == end) && (crashk_res.parent != NULL))
1539 release_resource(&crashk_res);
1540
1541 ram_res->start = end;
1542 ram_res->end = crashk_res.end;
1543 ram_res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
1544 ram_res->name = "System RAM";
1545
1546 crashk_res.end = end - 1;
1547
1548 insert_resource(&iomem_resource, ram_res);
1549 crash_unmap_reserved_pages();
1550
1551unlock:
1552 mutex_unlock(&kexec_mutex);
1553 return ret;
1554}
1555
1556static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
1557 size_t data_len)
1558{
1559 struct elf_note note;
1560
1561 note.n_namesz = strlen(name) + 1;
1562 note.n_descsz = data_len;
1563 note.n_type = type;
1564 memcpy(buf, &note, sizeof(note));
1565 buf += (sizeof(note) + 3)/4;
1566 memcpy(buf, name, note.n_namesz);
1567 buf += (note.n_namesz + 3)/4;
1568 memcpy(buf, data, note.n_descsz);
1569 buf += (note.n_descsz + 3)/4;
1570
1571 return buf;
1572}
1573
1574static void final_note(u32 *buf)
1575{
1576 struct elf_note note;
1577
1578 note.n_namesz = 0;
1579 note.n_descsz = 0;
1580 note.n_type = 0;
1581 memcpy(buf, &note, sizeof(note));
1582}
1583
1584void crash_save_cpu(struct pt_regs *regs, int cpu)
1585{
1586 struct elf_prstatus prstatus;
1587 u32 *buf;
1588
1589 if ((cpu < 0) || (cpu >= nr_cpu_ids))
1590 return;
1591
1592 /* Using ELF notes here is opportunistic.
1593 * I need a well defined structure format
1594 * for the data I pass, and I need tags
1595 * on the data to indicate what information I have
1596 * squirrelled away. ELF notes happen to provide
1597 * all of that, so there is no need to invent something new.
1598 */
1599 buf = (u32 *)per_cpu_ptr(crash_notes, cpu);
1600 if (!buf)
1601 return;
1602 memset(&prstatus, 0, sizeof(prstatus));
1603 prstatus.pr_pid = current->pid;
1604 elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
1605 buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
1606 &prstatus, sizeof(prstatus));
1607 final_note(buf);
1608}
1609
1610static int __init crash_notes_memory_init(void)
1611{
1612 /* Allocate memory for saving cpu registers. */
1613 crash_notes = alloc_percpu(note_buf_t);
1614 if (!crash_notes) {
1615 pr_warn("Kexec: Memory allocation for saving cpu register states failed\n");
1616 return -ENOMEM;
1617 }
1618 return 0;
1619}
1620subsys_initcall(crash_notes_memory_init);
1621
1622
1623/*
1624 * parsing the "crashkernel" commandline
1625 *
1626 * this code is intended to be called from architecture specific code
1627 */
1628
1629
1630/*
1631 * This function parses command lines in the format
1632 *
1633 * crashkernel=ramsize-range:size[,...][@offset]
1634 *
1635 * The function returns 0 on success and -EINVAL on failure.
1636 */
1637static int __init parse_crashkernel_mem(char *cmdline,
1638 unsigned long long system_ram,
1639 unsigned long long *crash_size,
1640 unsigned long long *crash_base)
1641{
1642 char *cur = cmdline, *tmp;
1643
1644 /* for each entry of the comma-separated list */
1645 do {
1646 unsigned long long start, end = ULLONG_MAX, size;
1647
1648 /* get the start of the range */
1649 start = memparse(cur, &tmp);
1650 if (cur == tmp) {
1651 pr_warn("crashkernel: Memory value expected\n");
1652 return -EINVAL;
1653 }
1654 cur = tmp;
1655 if (*cur != '-') {
1656 pr_warn("crashkernel: '-' expected\n");
1657 return -EINVAL;
1658 }
1659 cur++;
1660
1661 /* if no ':' is here, than we read the end */
1662 if (*cur != ':') {
1663 end = memparse(cur, &tmp);
1664 if (cur == tmp) {
1665 pr_warn("crashkernel: Memory value expected\n");
1666 return -EINVAL;
1667 }
1668 cur = tmp;
1669 if (end <= start) {
1670 pr_warn("crashkernel: end <= start\n");
1671 return -EINVAL;
1672 }
1673 }
1674
1675 if (*cur != ':') {
1676 pr_warn("crashkernel: ':' expected\n");
1677 return -EINVAL;
1678 }
1679 cur++;
1680
1681 size = memparse(cur, &tmp);
1682 if (cur == tmp) {
1683 pr_warn("Memory value expected\n");
1684 return -EINVAL;
1685 }
1686 cur = tmp;
1687 if (size >= system_ram) {
1688 pr_warn("crashkernel: invalid size\n");
1689 return -EINVAL;
1690 }
1691
1692 /* match ? */
1693 if (system_ram >= start && system_ram < end) {
1694 *crash_size = size;
1695 break;
1696 }
1697 } while (*cur++ == ',');
1698
1699 if (*crash_size > 0) {
1700 while (*cur && *cur != ' ' && *cur != '@')
1701 cur++;
1702 if (*cur == '@') {
1703 cur++;
1704 *crash_base = memparse(cur, &tmp);
1705 if (cur == tmp) {
1706 pr_warn("Memory value expected after '@'\n");
1707 return -EINVAL;
1708 }
1709 }
1710 }
1711
1712 return 0;
1713}
1714
1715/*
1716 * That function parses "simple" (old) crashkernel command lines like
1717 *
1718 * crashkernel=size[@offset]
1719 *
1720 * It returns 0 on success and -EINVAL on failure.
1721 */
1722static int __init parse_crashkernel_simple(char *cmdline,
1723 unsigned long long *crash_size,
1724 unsigned long long *crash_base)
1725{
1726 char *cur = cmdline;
1727
1728 *crash_size = memparse(cmdline, &cur);
1729 if (cmdline == cur) {
1730 pr_warn("crashkernel: memory value expected\n");
1731 return -EINVAL;
1732 }
1733
1734 if (*cur == '@')
1735 *crash_base = memparse(cur+1, &cur);
1736 else if (*cur != ' ' && *cur != '\0') {
1737 pr_warn("crashkernel: unrecognized char\n");
1738 return -EINVAL;
1739 }
1740
1741 return 0;
1742}
1743
1744#define SUFFIX_HIGH 0
1745#define SUFFIX_LOW 1
1746#define SUFFIX_NULL 2
1747static __initdata char *suffix_tbl[] = {
1748 [SUFFIX_HIGH] = ",high",
1749 [SUFFIX_LOW] = ",low",
1750 [SUFFIX_NULL] = NULL,
1751};
1752
1753/*
1754 * That function parses "suffix" crashkernel command lines like
1755 *
1756 * crashkernel=size,[high|low]
1757 *
1758 * It returns 0 on success and -EINVAL on failure.
1759 */
1760static int __init parse_crashkernel_suffix(char *cmdline,
1761 unsigned long long *crash_size,
1762 const char *suffix)
1763{
1764 char *cur = cmdline;
1765
1766 *crash_size = memparse(cmdline, &cur);
1767 if (cmdline == cur) {
1768 pr_warn("crashkernel: memory value expected\n");
1769 return -EINVAL;
1770 }
1771
1772 /* check with suffix */
1773 if (strncmp(cur, suffix, strlen(suffix))) {
1774 pr_warn("crashkernel: unrecognized char\n");
1775 return -EINVAL;
1776 }
1777 cur += strlen(suffix);
1778 if (*cur != ' ' && *cur != '\0') {
1779 pr_warn("crashkernel: unrecognized char\n");
1780 return -EINVAL;
1781 }
1782
1783 return 0;
1784}
1785
1786static __init char *get_last_crashkernel(char *cmdline,
1787 const char *name,
1788 const char *suffix)
1789{
1790 char *p = cmdline, *ck_cmdline = NULL;
1791
1792 /* find crashkernel and use the last one if there are more */
1793 p = strstr(p, name);
1794 while (p) {
1795 char *end_p = strchr(p, ' ');
1796 char *q;
1797
1798 if (!end_p)
1799 end_p = p + strlen(p);
1800
1801 if (!suffix) {
1802 int i;
1803
1804 /* skip the one with any known suffix */
1805 for (i = 0; suffix_tbl[i]; i++) {
1806 q = end_p - strlen(suffix_tbl[i]);
1807 if (!strncmp(q, suffix_tbl[i],
1808 strlen(suffix_tbl[i])))
1809 goto next;
1810 }
1811 ck_cmdline = p;
1812 } else {
1813 q = end_p - strlen(suffix);
1814 if (!strncmp(q, suffix, strlen(suffix)))
1815 ck_cmdline = p;
1816 }
1817next:
1818 p = strstr(p+1, name);
1819 }
1820
1821 if (!ck_cmdline)
1822 return NULL;
1823
1824 return ck_cmdline;
1825}
1826
1827static int __init __parse_crashkernel(char *cmdline,
1828 unsigned long long system_ram,
1829 unsigned long long *crash_size,
1830 unsigned long long *crash_base,
1831 const char *name,
1832 const char *suffix)
1833{
1834 char *first_colon, *first_space;
1835 char *ck_cmdline;
1836
1837 BUG_ON(!crash_size || !crash_base);
1838 *crash_size = 0;
1839 *crash_base = 0;
1840
1841 ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
1842
1843 if (!ck_cmdline)
1844 return -EINVAL;
1845
1846 ck_cmdline += strlen(name);
1847
1848 if (suffix)
1849 return parse_crashkernel_suffix(ck_cmdline, crash_size,
1850 suffix);
1851 /*
1852 * if the commandline contains a ':', then that's the extended
1853 * syntax -- if not, it must be the classic syntax
1854 */
1855 first_colon = strchr(ck_cmdline, ':');
1856 first_space = strchr(ck_cmdline, ' ');
1857 if (first_colon && (!first_space || first_colon < first_space))
1858 return parse_crashkernel_mem(ck_cmdline, system_ram,
1859 crash_size, crash_base);
1860
1861 return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
1862}
1863
1864/*
1865 * That function is the entry point for command line parsing and should be
1866 * called from the arch-specific code.
1867 */
1868int __init parse_crashkernel(char *cmdline,
1869 unsigned long long system_ram,
1870 unsigned long long *crash_size,
1871 unsigned long long *crash_base)
1872{
1873 return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1874 "crashkernel=", NULL);
1875}
1876
1877int __init parse_crashkernel_high(char *cmdline,
1878 unsigned long long system_ram,
1879 unsigned long long *crash_size,
1880 unsigned long long *crash_base)
1881{
1882 return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1883 "crashkernel=", suffix_tbl[SUFFIX_HIGH]);
1884}
1885
1886int __init parse_crashkernel_low(char *cmdline,
1887 unsigned long long system_ram,
1888 unsigned long long *crash_size,
1889 unsigned long long *crash_base)
1890{
1891 return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1892 "crashkernel=", suffix_tbl[SUFFIX_LOW]);
1893}
1894
1895static void update_vmcoreinfo_note(void)
1896{
1897 u32 *buf = vmcoreinfo_note;
1898
1899 if (!vmcoreinfo_size)
1900 return;
1901 buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
1902 vmcoreinfo_size);
1903 final_note(buf);
1904}
1905
1906void crash_save_vmcoreinfo(void)
1907{
1908 vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds());
1909 update_vmcoreinfo_note();
1910}
1911
1912void vmcoreinfo_append_str(const char *fmt, ...)
1913{
1914 va_list args;
1915 char buf[0x50];
1916 size_t r;
1917
1918 va_start(args, fmt);
1919 r = vscnprintf(buf, sizeof(buf), fmt, args);
1920 va_end(args);
1921
1922 r = min(r, vmcoreinfo_max_size - vmcoreinfo_size);
1923
1924 memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
1925
1926 vmcoreinfo_size += r;
1927}
1928
1929/*
1930 * provide an empty default implementation here -- architecture
1931 * code may override this
1932 */
1933void __weak arch_crash_save_vmcoreinfo(void)
1934{}
1935
1936unsigned long __weak paddr_vmcoreinfo_note(void)
1937{
1938 return __pa((unsigned long)(char *)&vmcoreinfo_note);
1939}
1940
1941static int __init crash_save_vmcoreinfo_init(void)
1942{
1943 VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
1944 VMCOREINFO_PAGESIZE(PAGE_SIZE);
1945
1946 VMCOREINFO_SYMBOL(init_uts_ns);
1947 VMCOREINFO_SYMBOL(node_online_map);
1948#ifdef CONFIG_MMU
1949 VMCOREINFO_SYMBOL(swapper_pg_dir);
1950#endif
1951 VMCOREINFO_SYMBOL(_stext);
1952 VMCOREINFO_SYMBOL(vmap_area_list);
1953
1954#ifndef CONFIG_NEED_MULTIPLE_NODES
1955 VMCOREINFO_SYMBOL(mem_map);
1956 VMCOREINFO_SYMBOL(contig_page_data);
1957#endif
1958#ifdef CONFIG_SPARSEMEM
1959 VMCOREINFO_SYMBOL(mem_section);
1960 VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
1961 VMCOREINFO_STRUCT_SIZE(mem_section);
1962 VMCOREINFO_OFFSET(mem_section, section_mem_map);
1963#endif
1964 VMCOREINFO_STRUCT_SIZE(page);
1965 VMCOREINFO_STRUCT_SIZE(pglist_data);
1966 VMCOREINFO_STRUCT_SIZE(zone);
1967 VMCOREINFO_STRUCT_SIZE(free_area);
1968 VMCOREINFO_STRUCT_SIZE(list_head);
1969 VMCOREINFO_SIZE(nodemask_t);
1970 VMCOREINFO_OFFSET(page, flags);
1971 VMCOREINFO_OFFSET(page, _count);
1972 VMCOREINFO_OFFSET(page, mapping);
1973 VMCOREINFO_OFFSET(page, lru);
1974 VMCOREINFO_OFFSET(page, _mapcount);
1975 VMCOREINFO_OFFSET(page, private);
1976 VMCOREINFO_OFFSET(pglist_data, node_zones);
1977 VMCOREINFO_OFFSET(pglist_data, nr_zones);
1978#ifdef CONFIG_FLAT_NODE_MEM_MAP
1979 VMCOREINFO_OFFSET(pglist_data, node_mem_map);
1980#endif
1981 VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
1982 VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
1983 VMCOREINFO_OFFSET(pglist_data, node_id);
1984 VMCOREINFO_OFFSET(zone, free_area);
1985 VMCOREINFO_OFFSET(zone, vm_stat);
1986 VMCOREINFO_OFFSET(zone, spanned_pages);
1987 VMCOREINFO_OFFSET(free_area, free_list);
1988 VMCOREINFO_OFFSET(list_head, next);
1989 VMCOREINFO_OFFSET(list_head, prev);
1990 VMCOREINFO_OFFSET(vmap_area, va_start);
1991 VMCOREINFO_OFFSET(vmap_area, list);
1992 VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
1993 log_buf_kexec_setup();
1994 VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
1995 VMCOREINFO_NUMBER(NR_FREE_PAGES);
1996 VMCOREINFO_NUMBER(PG_lru);
1997 VMCOREINFO_NUMBER(PG_private);
1998 VMCOREINFO_NUMBER(PG_swapcache);
1999 VMCOREINFO_NUMBER(PG_slab);
2000#ifdef CONFIG_MEMORY_FAILURE
2001 VMCOREINFO_NUMBER(PG_hwpoison);
2002#endif
2003 VMCOREINFO_NUMBER(PG_head_mask);
2004 VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
2005#ifdef CONFIG_HUGETLBFS
2006 VMCOREINFO_SYMBOL(free_huge_page);
2007#endif
2008
2009 arch_crash_save_vmcoreinfo();
2010 update_vmcoreinfo_note();
2011
2012 return 0;
2013}
2014
2015subsys_initcall(crash_save_vmcoreinfo_init);
2016
2017#ifdef CONFIG_KEXEC_FILE
2018static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
2019 struct kexec_buf *kbuf)
2020{
2021 struct kimage *image = kbuf->image;
2022 unsigned long temp_start, temp_end;
2023
2024 temp_end = min(end, kbuf->buf_max);
2025 temp_start = temp_end - kbuf->memsz;
2026
2027 do {
2028 /* align down start */
2029 temp_start = temp_start & (~(kbuf->buf_align - 1));
2030
2031 if (temp_start < start || temp_start < kbuf->buf_min)
2032 return 0;
2033
2034 temp_end = temp_start + kbuf->memsz - 1;
2035
2036 /*
2037 * Make sure this does not conflict with any of existing
2038 * segments
2039 */
2040 if (kimage_is_destination_range(image, temp_start, temp_end)) {
2041 temp_start = temp_start - PAGE_SIZE;
2042 continue;
2043 }
2044
2045 /* We found a suitable memory range */
2046 break;
2047 } while (1);
2048
2049 /* If we are here, we found a suitable memory range */
2050 kbuf->mem = temp_start;
2051
2052 /* Success, stop navigating through remaining System RAM ranges */
2053 return 1;
2054}
2055
2056static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
2057 struct kexec_buf *kbuf)
2058{
2059 struct kimage *image = kbuf->image;
2060 unsigned long temp_start, temp_end;
2061
2062 temp_start = max(start, kbuf->buf_min);
2063
2064 do {
2065 temp_start = ALIGN(temp_start, kbuf->buf_align);
2066 temp_end = temp_start + kbuf->memsz - 1;
2067
2068 if (temp_end > end || temp_end > kbuf->buf_max)
2069 return 0;
2070 /*
2071 * Make sure this does not conflict with any of existing
2072 * segments
2073 */
2074 if (kimage_is_destination_range(image, temp_start, temp_end)) {
2075 temp_start = temp_start + PAGE_SIZE;
2076 continue;
2077 }
2078
2079 /* We found a suitable memory range */
2080 break;
2081 } while (1);
2082
2083 /* If we are here, we found a suitable memory range */
2084 kbuf->mem = temp_start;
2085
2086 /* Success, stop navigating through remaining System RAM ranges */
2087 return 1;
2088}
2089
2090static int locate_mem_hole_callback(u64 start, u64 end, void *arg)
2091{
2092 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
2093 unsigned long sz = end - start + 1;
2094
2095 /* Returning 0 will take to next memory range */
2096 if (sz < kbuf->memsz)
2097 return 0;
2098
2099 if (end < kbuf->buf_min || start > kbuf->buf_max)
2100 return 0;
2101
2102 /*
2103 * Allocate memory top down with-in ram range. Otherwise bottom up
2104 * allocation.
2105 */
2106 if (kbuf->top_down)
2107 return locate_mem_hole_top_down(start, end, kbuf);
2108 return locate_mem_hole_bottom_up(start, end, kbuf);
2109}
2110
2111/*
2112 * Helper function for placing a buffer in a kexec segment. This assumes
2113 * that kexec_mutex is held.
2114 */
2115int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
2116 unsigned long memsz, unsigned long buf_align,
2117 unsigned long buf_min, unsigned long buf_max,
2118 bool top_down, unsigned long *load_addr)
2119{
2120
2121 struct kexec_segment *ksegment;
2122 struct kexec_buf buf, *kbuf;
2123 int ret;
2124
2125 /* Currently adding segment this way is allowed only in file mode */
2126 if (!image->file_mode)
2127 return -EINVAL;
2128
2129 if (image->nr_segments >= KEXEC_SEGMENT_MAX)
2130 return -EINVAL;
2131
2132 /*
2133 * Make sure we are not trying to add buffer after allocating
2134 * control pages. All segments need to be placed first before
2135 * any control pages are allocated. As control page allocation
2136 * logic goes through list of segments to make sure there are
2137 * no destination overlaps.
2138 */
2139 if (!list_empty(&image->control_pages)) {
2140 WARN_ON(1);
2141 return -EINVAL;
2142 }
2143
2144 memset(&buf, 0, sizeof(struct kexec_buf));
2145 kbuf = &buf;
2146 kbuf->image = image;
2147 kbuf->buffer = buffer;
2148 kbuf->bufsz = bufsz;
2149
2150 kbuf->memsz = ALIGN(memsz, PAGE_SIZE);
2151 kbuf->buf_align = max(buf_align, PAGE_SIZE);
2152 kbuf->buf_min = buf_min;
2153 kbuf->buf_max = buf_max;
2154 kbuf->top_down = top_down;
2155
2156 /* Walk the RAM ranges and allocate a suitable range for the buffer */
2157 if (image->type == KEXEC_TYPE_CRASH)
2158 ret = walk_iomem_res("Crash kernel",
2159 IORESOURCE_MEM | IORESOURCE_BUSY,
2160 crashk_res.start, crashk_res.end, kbuf,
2161 locate_mem_hole_callback);
2162 else
2163 ret = walk_system_ram_res(0, -1, kbuf,
2164 locate_mem_hole_callback);
2165 if (ret != 1) {
2166 /* A suitable memory range could not be found for buffer */
2167 return -EADDRNOTAVAIL;
2168 }
2169
2170 /* Found a suitable memory range */
2171 ksegment = &image->segment[image->nr_segments];
2172 ksegment->kbuf = kbuf->buffer;
2173 ksegment->bufsz = kbuf->bufsz;
2174 ksegment->mem = kbuf->mem;
2175 ksegment->memsz = kbuf->memsz;
2176 image->nr_segments++;
2177 *load_addr = ksegment->mem;
2178 return 0;
2179}
2180
2181/* Calculate and store the digest of segments */
2182static int kexec_calculate_store_digests(struct kimage *image)
2183{
2184 struct crypto_shash *tfm;
2185 struct shash_desc *desc;
2186 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
2187 size_t desc_size, nullsz;
2188 char *digest;
2189 void *zero_buf;
2190 struct kexec_sha_region *sha_regions;
2191 struct purgatory_info *pi = &image->purgatory_info;
2192
2193 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
2194 zero_buf_sz = PAGE_SIZE;
2195
2196 tfm = crypto_alloc_shash("sha256", 0, 0);
2197 if (IS_ERR(tfm)) {
2198 ret = PTR_ERR(tfm);
2199 goto out;
2200 }
2201
2202 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
2203 desc = kzalloc(desc_size, GFP_KERNEL);
2204 if (!desc) {
2205 ret = -ENOMEM;
2206 goto out_free_tfm;
2207 }
2208
2209 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
2210 sha_regions = vzalloc(sha_region_sz);
2211 if (!sha_regions)
2212 goto out_free_desc;
2213
2214 desc->tfm = tfm;
2215 desc->flags = 0;
2216
2217 ret = crypto_shash_init(desc);
2218 if (ret < 0)
2219 goto out_free_sha_regions;
2220
2221 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
2222 if (!digest) {
2223 ret = -ENOMEM;
2224 goto out_free_sha_regions;
2225 }
2226
2227 for (j = i = 0; i < image->nr_segments; i++) {
2228 struct kexec_segment *ksegment;
2229
2230 ksegment = &image->segment[i];
2231 /*
2232 * Skip purgatory as it will be modified once we put digest
2233 * info in purgatory.
2234 */
2235 if (ksegment->kbuf == pi->purgatory_buf)
2236 continue;
2237
2238 ret = crypto_shash_update(desc, ksegment->kbuf,
2239 ksegment->bufsz);
2240 if (ret)
2241 break;
2242
2243 /*
2244 * Assume rest of the buffer is filled with zero and
2245 * update digest accordingly.
2246 */
2247 nullsz = ksegment->memsz - ksegment->bufsz;
2248 while (nullsz) {
2249 unsigned long bytes = nullsz;
2250
2251 if (bytes > zero_buf_sz)
2252 bytes = zero_buf_sz;
2253 ret = crypto_shash_update(desc, zero_buf, bytes);
2254 if (ret)
2255 break;
2256 nullsz -= bytes;
2257 }
2258
2259 if (ret)
2260 break;
2261
2262 sha_regions[j].start = ksegment->mem;
2263 sha_regions[j].len = ksegment->memsz;
2264 j++;
2265 }
2266
2267 if (!ret) {
2268 ret = crypto_shash_final(desc, digest);
2269 if (ret)
2270 goto out_free_digest;
2271 ret = kexec_purgatory_get_set_symbol(image, "sha_regions",
2272 sha_regions, sha_region_sz, 0);
2273 if (ret)
2274 goto out_free_digest;
2275
2276 ret = kexec_purgatory_get_set_symbol(image, "sha256_digest",
2277 digest, SHA256_DIGEST_SIZE, 0);
2278 if (ret)
2279 goto out_free_digest;
2280 }
2281
2282out_free_digest:
2283 kfree(digest);
2284out_free_sha_regions:
2285 vfree(sha_regions);
2286out_free_desc:
2287 kfree(desc);
2288out_free_tfm:
2289 kfree(tfm);
2290out:
2291 return ret;
2292}
2293
2294/* Actually load purgatory. Lot of code taken from kexec-tools */
2295static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
2296 unsigned long max, int top_down)
2297{
2298 struct purgatory_info *pi = &image->purgatory_info;
2299 unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad;
2300 unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset;
2301 unsigned char *buf_addr, *src;
2302 int i, ret = 0, entry_sidx = -1;
2303 const Elf_Shdr *sechdrs_c;
2304 Elf_Shdr *sechdrs = NULL;
2305 void *purgatory_buf = NULL;
2306
2307 /*
2308 * sechdrs_c points to section headers in purgatory and are read
2309 * only. No modifications allowed.
2310 */
2311 sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff;
2312
2313 /*
2314 * We can not modify sechdrs_c[] and its fields. It is read only.
2315 * Copy it over to a local copy where one can store some temporary
2316 * data and free it at the end. We need to modify ->sh_addr and
2317 * ->sh_offset fields to keep track of permanent and temporary
2318 * locations of sections.
2319 */
2320 sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr));
2321 if (!sechdrs)
2322 return -ENOMEM;
2323
2324 memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr));
2325
2326 /*
2327 * We seem to have multiple copies of sections. First copy is which
2328 * is embedded in kernel in read only section. Some of these sections
2329 * will be copied to a temporary buffer and relocated. And these
2330 * sections will finally be copied to their final destination at
2331 * segment load time.
2332 *
2333 * Use ->sh_offset to reflect section address in memory. It will
2334 * point to original read only copy if section is not allocatable.
2335 * Otherwise it will point to temporary copy which will be relocated.
2336 *
2337 * Use ->sh_addr to contain final address of the section where it
2338 * will go during execution time.
2339 */
2340 for (i = 0; i < pi->ehdr->e_shnum; i++) {
2341 if (sechdrs[i].sh_type == SHT_NOBITS)
2342 continue;
2343
2344 sechdrs[i].sh_offset = (unsigned long)pi->ehdr +
2345 sechdrs[i].sh_offset;
2346 }
2347
2348 /*
2349 * Identify entry point section and make entry relative to section
2350 * start.
2351 */
2352 entry = pi->ehdr->e_entry;
2353 for (i = 0; i < pi->ehdr->e_shnum; i++) {
2354 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
2355 continue;
2356
2357 if (!(sechdrs[i].sh_flags & SHF_EXECINSTR))
2358 continue;
2359
2360 /* Make entry section relative */
2361 if (sechdrs[i].sh_addr <= pi->ehdr->e_entry &&
2362 ((sechdrs[i].sh_addr + sechdrs[i].sh_size) >
2363 pi->ehdr->e_entry)) {
2364 entry_sidx = i;
2365 entry -= sechdrs[i].sh_addr;
2366 break;
2367 }
2368 }
2369
2370 /* Determine how much memory is needed to load relocatable object. */
2371 buf_align = 1;
2372 bss_align = 1;
2373 buf_sz = 0;
2374 bss_sz = 0;
2375
2376 for (i = 0; i < pi->ehdr->e_shnum; i++) {
2377 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
2378 continue;
2379
2380 align = sechdrs[i].sh_addralign;
2381 if (sechdrs[i].sh_type != SHT_NOBITS) {
2382 if (buf_align < align)
2383 buf_align = align;
2384 buf_sz = ALIGN(buf_sz, align);
2385 buf_sz += sechdrs[i].sh_size;
2386 } else {
2387 /* bss section */
2388 if (bss_align < align)
2389 bss_align = align;
2390 bss_sz = ALIGN(bss_sz, align);
2391 bss_sz += sechdrs[i].sh_size;
2392 }
2393 }
2394
2395 /* Determine the bss padding required to align bss properly */
2396 bss_pad = 0;
2397 if (buf_sz & (bss_align - 1))
2398 bss_pad = bss_align - (buf_sz & (bss_align - 1));
2399
2400 memsz = buf_sz + bss_pad + bss_sz;
2401
2402 /* Allocate buffer for purgatory */
2403 purgatory_buf = vzalloc(buf_sz);
2404 if (!purgatory_buf) {
2405 ret = -ENOMEM;
2406 goto out;
2407 }
2408
2409 if (buf_align < bss_align)
2410 buf_align = bss_align;
2411
2412 /* Add buffer to segment list */
2413 ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz,
2414 buf_align, min, max, top_down,
2415 &pi->purgatory_load_addr);
2416 if (ret)
2417 goto out;
2418
2419 /* Load SHF_ALLOC sections */
2420 buf_addr = purgatory_buf;
2421 load_addr = curr_load_addr = pi->purgatory_load_addr;
2422 bss_addr = load_addr + buf_sz + bss_pad;
2423
2424 for (i = 0; i < pi->ehdr->e_shnum; i++) {
2425 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
2426 continue;
2427
2428 align = sechdrs[i].sh_addralign;
2429 if (sechdrs[i].sh_type != SHT_NOBITS) {
2430 curr_load_addr = ALIGN(curr_load_addr, align);
2431 offset = curr_load_addr - load_addr;
2432 /* We already modifed ->sh_offset to keep src addr */
2433 src = (char *) sechdrs[i].sh_offset;
2434 memcpy(buf_addr + offset, src, sechdrs[i].sh_size);
2435
2436 /* Store load address and source address of section */
2437 sechdrs[i].sh_addr = curr_load_addr;
2438
2439 /*
2440 * This section got copied to temporary buffer. Update
2441 * ->sh_offset accordingly.
2442 */
2443 sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset);
2444
2445 /* Advance to the next address */
2446 curr_load_addr += sechdrs[i].sh_size;
2447 } else {
2448 bss_addr = ALIGN(bss_addr, align);
2449 sechdrs[i].sh_addr = bss_addr;
2450 bss_addr += sechdrs[i].sh_size;
2451 }
2452 }
2453
2454 /* Update entry point based on load address of text section */
2455 if (entry_sidx >= 0)
2456 entry += sechdrs[entry_sidx].sh_addr;
2457
2458 /* Make kernel jump to purgatory after shutdown */
2459 image->start = entry;
2460
2461 /* Used later to get/set symbol values */
2462 pi->sechdrs = sechdrs;
2463
2464 /*
2465 * Used later to identify which section is purgatory and skip it
2466 * from checksumming.
2467 */
2468 pi->purgatory_buf = purgatory_buf;
2469 return ret;
2470out:
2471 vfree(sechdrs);
2472 vfree(purgatory_buf);
2473 return ret;
2474}
2475
2476static int kexec_apply_relocations(struct kimage *image)
2477{
2478 int i, ret;
2479 struct purgatory_info *pi = &image->purgatory_info;
2480 Elf_Shdr *sechdrs = pi->sechdrs;
2481
2482 /* Apply relocations */
2483 for (i = 0; i < pi->ehdr->e_shnum; i++) {
2484 Elf_Shdr *section, *symtab;
2485
2486 if (sechdrs[i].sh_type != SHT_RELA &&
2487 sechdrs[i].sh_type != SHT_REL)
2488 continue;
2489
2490 /*
2491 * For section of type SHT_RELA/SHT_REL,
2492 * ->sh_link contains section header index of associated
2493 * symbol table. And ->sh_info contains section header
2494 * index of section to which relocations apply.
2495 */
2496 if (sechdrs[i].sh_info >= pi->ehdr->e_shnum ||
2497 sechdrs[i].sh_link >= pi->ehdr->e_shnum)
2498 return -ENOEXEC;
2499
2500 section = &sechdrs[sechdrs[i].sh_info];
2501 symtab = &sechdrs[sechdrs[i].sh_link];
2502
2503 if (!(section->sh_flags & SHF_ALLOC))
2504 continue;
2505
2506 /*
2507 * symtab->sh_link contain section header index of associated
2508 * string table.
2509 */
2510 if (symtab->sh_link >= pi->ehdr->e_shnum)
2511 /* Invalid section number? */
2512 continue;
2513
2514 /*
2515 * Respective archicture needs to provide support for applying
2516 * relocations of type SHT_RELA/SHT_REL.
2517 */
2518 if (sechdrs[i].sh_type == SHT_RELA)
2519 ret = arch_kexec_apply_relocations_add(pi->ehdr,
2520 sechdrs, i);
2521 else if (sechdrs[i].sh_type == SHT_REL)
2522 ret = arch_kexec_apply_relocations(pi->ehdr,
2523 sechdrs, i);
2524 if (ret)
2525 return ret;
2526 }
2527
2528 return 0;
2529}
2530
2531/* Load relocatable purgatory object and relocate it appropriately */
2532int kexec_load_purgatory(struct kimage *image, unsigned long min,
2533 unsigned long max, int top_down,
2534 unsigned long *load_addr)
2535{
2536 struct purgatory_info *pi = &image->purgatory_info;
2537 int ret;
2538
2539 if (kexec_purgatory_size <= 0)
2540 return -EINVAL;
2541
2542 if (kexec_purgatory_size < sizeof(Elf_Ehdr))
2543 return -ENOEXEC;
2544
2545 pi->ehdr = (Elf_Ehdr *)kexec_purgatory;
2546
2547 if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0
2548 || pi->ehdr->e_type != ET_REL
2549 || !elf_check_arch(pi->ehdr)
2550 || pi->ehdr->e_shentsize != sizeof(Elf_Shdr))
2551 return -ENOEXEC;
2552
2553 if (pi->ehdr->e_shoff >= kexec_purgatory_size
2554 || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) >
2555 kexec_purgatory_size - pi->ehdr->e_shoff))
2556 return -ENOEXEC;
2557
2558 ret = __kexec_load_purgatory(image, min, max, top_down);
2559 if (ret)
2560 return ret;
2561
2562 ret = kexec_apply_relocations(image);
2563 if (ret)
2564 goto out;
2565
2566 *load_addr = pi->purgatory_load_addr;
2567 return 0;
2568out:
2569 vfree(pi->sechdrs);
2570 vfree(pi->purgatory_buf);
2571 return ret;
2572}
2573
2574static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
2575 const char *name)
2576{
2577 Elf_Sym *syms;
2578 Elf_Shdr *sechdrs;
2579 Elf_Ehdr *ehdr;
2580 int i, k;
2581 const char *strtab;
2582
2583 if (!pi->sechdrs || !pi->ehdr)
2584 return NULL;
2585
2586 sechdrs = pi->sechdrs;
2587 ehdr = pi->ehdr;
2588
2589 for (i = 0; i < ehdr->e_shnum; i++) {
2590 if (sechdrs[i].sh_type != SHT_SYMTAB)
2591 continue;
2592
2593 if (sechdrs[i].sh_link >= ehdr->e_shnum)
2594 /* Invalid strtab section number */
2595 continue;
2596 strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset;
2597 syms = (Elf_Sym *)sechdrs[i].sh_offset;
2598
2599 /* Go through symbols for a match */
2600 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
2601 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
2602 continue;
2603
2604 if (strcmp(strtab + syms[k].st_name, name) != 0)
2605 continue;
2606
2607 if (syms[k].st_shndx == SHN_UNDEF ||
2608 syms[k].st_shndx >= ehdr->e_shnum) {
2609 pr_debug("Symbol: %s has bad section index %d.\n",
2610 name, syms[k].st_shndx);
2611 return NULL;
2612 }
2613
2614 /* Found the symbol we are looking for */
2615 return &syms[k];
2616 }
2617 }
2618
2619 return NULL;
2620}
2621
2622void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
2623{
2624 struct purgatory_info *pi = &image->purgatory_info;
2625 Elf_Sym *sym;
2626 Elf_Shdr *sechdr;
2627
2628 sym = kexec_purgatory_find_symbol(pi, name);
2629 if (!sym)
2630 return ERR_PTR(-EINVAL);
2631
2632 sechdr = &pi->sechdrs[sym->st_shndx];
2633
2634 /*
2635 * Returns the address where symbol will finally be loaded after
2636 * kexec_load_segment()
2637 */
2638 return (void *)(sechdr->sh_addr + sym->st_value);
2639}
2640
2641/*
2642 * Get or set value of a symbol. If "get_value" is true, symbol value is
2643 * returned in buf otherwise symbol value is set based on value in buf.
2644 */
2645int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
2646 void *buf, unsigned int size, bool get_value)
2647{
2648 Elf_Sym *sym;
2649 Elf_Shdr *sechdrs;
2650 struct purgatory_info *pi = &image->purgatory_info;
2651 char *sym_buf;
2652
2653 sym = kexec_purgatory_find_symbol(pi, name);
2654 if (!sym)
2655 return -EINVAL;
2656
2657 if (sym->st_size != size) {
2658 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
2659 name, (unsigned long)sym->st_size, size);
2660 return -EINVAL;
2661 }
2662
2663 sechdrs = pi->sechdrs;
2664
2665 if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
2666 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
2667 get_value ? "get" : "set");
2668 return -EINVAL;
2669 }
2670
2671 sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset +
2672 sym->st_value;
2673
2674 if (get_value)
2675 memcpy((void *)buf, sym_buf, size);
2676 else
2677 memcpy((void *)sym_buf, buf, size);
2678
2679 return 0;
2680}
2681#endif /* CONFIG_KEXEC_FILE */
2682
2683/*
2684 * Move into place and start executing a preloaded standalone
2685 * executable. If nothing was preloaded return an error.
2686 */
2687int kernel_kexec(void)
2688{
2689 int error = 0;
2690
2691 if (!mutex_trylock(&kexec_mutex))
2692 return -EBUSY;
2693 if (!kexec_image) {
2694 error = -EINVAL;
2695 goto Unlock;
2696 }
2697
2698#ifdef CONFIG_KEXEC_JUMP
2699 if (kexec_image->preserve_context) {
2700 lock_system_sleep();
2701 pm_prepare_console();
2702 error = freeze_processes();
2703 if (error) {
2704 error = -EBUSY;
2705 goto Restore_console;
2706 }
2707 suspend_console();
2708 error = dpm_suspend_start(PMSG_FREEZE);
2709 if (error)
2710 goto Resume_console;
2711 /* At this point, dpm_suspend_start() has been called,
2712 * but *not* dpm_suspend_end(). We *must* call
2713 * dpm_suspend_end() now. Otherwise, drivers for
2714 * some devices (e.g. interrupt controllers) become
2715 * desynchronized with the actual state of the
2716 * hardware at resume time, and evil weirdness ensues.
2717 */
2718 error = dpm_suspend_end(PMSG_FREEZE);
2719 if (error)
2720 goto Resume_devices;
2721 error = disable_nonboot_cpus();
2722 if (error)
2723 goto Enable_cpus;
2724 local_irq_disable();
2725 error = syscore_suspend();
2726 if (error)
2727 goto Enable_irqs;
2728 } else
2729#endif
2730 {
2731 kexec_in_progress = true;
2732 kernel_restart_prepare(NULL);
2733 migrate_to_reboot_cpu();
2734
2735 /*
2736 * migrate_to_reboot_cpu() disables CPU hotplug assuming that
2737 * no further code needs to use CPU hotplug (which is true in
2738 * the reboot case). However, the kexec path depends on using
2739 * CPU hotplug again; so re-enable it here.
2740 */
2741 cpu_hotplug_enable();
2742 pr_emerg("Starting new kernel\n");
2743 machine_shutdown();
2744 }
2745
2746 machine_kexec(kexec_image);
2747
2748#ifdef CONFIG_KEXEC_JUMP
2749 if (kexec_image->preserve_context) {
2750 syscore_resume();
2751 Enable_irqs:
2752 local_irq_enable();
2753 Enable_cpus:
2754 enable_nonboot_cpus();
2755 dpm_resume_start(PMSG_RESTORE);
2756 Resume_devices:
2757 dpm_resume_end(PMSG_RESTORE);
2758 Resume_console:
2759 resume_console();
2760 thaw_processes();
2761 Restore_console:
2762 pm_restore_console();
2763 unlock_system_sleep();
2764 }
2765#endif
2766
2767 Unlock:
2768 mutex_unlock(&kexec_mutex);
2769 return error;
2770}