xref: /openbmc/linux/kernel/kexec.c (revision fd589a8f)
1 /*
2  * kexec.c - kexec system call
3  * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
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 #include <linux/capability.h>
10 #include <linux/mm.h>
11 #include <linux/file.h>
12 #include <linux/slab.h>
13 #include <linux/fs.h>
14 #include <linux/kexec.h>
15 #include <linux/mutex.h>
16 #include <linux/list.h>
17 #include <linux/highmem.h>
18 #include <linux/syscalls.h>
19 #include <linux/reboot.h>
20 #include <linux/ioport.h>
21 #include <linux/hardirq.h>
22 #include <linux/elf.h>
23 #include <linux/elfcore.h>
24 #include <linux/utsrelease.h>
25 #include <linux/utsname.h>
26 #include <linux/numa.h>
27 #include <linux/suspend.h>
28 #include <linux/device.h>
29 #include <linux/freezer.h>
30 #include <linux/pm.h>
31 #include <linux/cpu.h>
32 #include <linux/console.h>
33 #include <linux/vmalloc.h>
34 
35 #include <asm/page.h>
36 #include <asm/uaccess.h>
37 #include <asm/io.h>
38 #include <asm/system.h>
39 #include <asm/sections.h>
40 
41 /* Per cpu memory for storing cpu states in case of system crash. */
42 note_buf_t* crash_notes;
43 
44 /* vmcoreinfo stuff */
45 static unsigned char vmcoreinfo_data[VMCOREINFO_BYTES];
46 u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
47 size_t vmcoreinfo_size;
48 size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
49 
50 /* Location of the reserved area for the crash kernel */
51 struct resource crashk_res = {
52 	.name  = "Crash kernel",
53 	.start = 0,
54 	.end   = 0,
55 	.flags = IORESOURCE_BUSY | IORESOURCE_MEM
56 };
57 
58 int kexec_should_crash(struct task_struct *p)
59 {
60 	if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
61 		return 1;
62 	return 0;
63 }
64 
65 /*
66  * When kexec transitions to the new kernel there is a one-to-one
67  * mapping between physical and virtual addresses.  On processors
68  * where you can disable the MMU this is trivial, and easy.  For
69  * others it is still a simple predictable page table to setup.
70  *
71  * In that environment kexec copies the new kernel to its final
72  * resting place.  This means I can only support memory whose
73  * physical address can fit in an unsigned long.  In particular
74  * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
75  * If the assembly stub has more restrictive requirements
76  * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
77  * defined more restrictively in <asm/kexec.h>.
78  *
79  * The code for the transition from the current kernel to the
80  * the new kernel is placed in the control_code_buffer, whose size
81  * is given by KEXEC_CONTROL_PAGE_SIZE.  In the best case only a single
82  * page of memory is necessary, but some architectures require more.
83  * Because this memory must be identity mapped in the transition from
84  * virtual to physical addresses it must live in the range
85  * 0 - TASK_SIZE, as only the user space mappings are arbitrarily
86  * modifiable.
87  *
88  * The assembly stub in the control code buffer is passed a linked list
89  * of descriptor pages detailing the source pages of the new kernel,
90  * and the destination addresses of those source pages.  As this data
91  * structure is not used in the context of the current OS, it must
92  * be self-contained.
93  *
94  * The code has been made to work with highmem pages and will use a
95  * destination page in its final resting place (if it happens
96  * to allocate it).  The end product of this is that most of the
97  * physical address space, and most of RAM can be used.
98  *
99  * Future directions include:
100  *  - allocating a page table with the control code buffer identity
101  *    mapped, to simplify machine_kexec and make kexec_on_panic more
102  *    reliable.
103  */
104 
105 /*
106  * KIMAGE_NO_DEST is an impossible destination address..., for
107  * allocating pages whose destination address we do not care about.
108  */
109 #define KIMAGE_NO_DEST (-1UL)
110 
111 static int kimage_is_destination_range(struct kimage *image,
112 				       unsigned long start, unsigned long end);
113 static struct page *kimage_alloc_page(struct kimage *image,
114 				       gfp_t gfp_mask,
115 				       unsigned long dest);
116 
117 static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
118 	                    unsigned long nr_segments,
119                             struct kexec_segment __user *segments)
120 {
121 	size_t segment_bytes;
122 	struct kimage *image;
123 	unsigned long i;
124 	int result;
125 
126 	/* Allocate a controlling structure */
127 	result = -ENOMEM;
128 	image = kzalloc(sizeof(*image), GFP_KERNEL);
129 	if (!image)
130 		goto out;
131 
132 	image->head = 0;
133 	image->entry = &image->head;
134 	image->last_entry = &image->head;
135 	image->control_page = ~0; /* By default this does not apply */
136 	image->start = entry;
137 	image->type = KEXEC_TYPE_DEFAULT;
138 
139 	/* Initialize the list of control pages */
140 	INIT_LIST_HEAD(&image->control_pages);
141 
142 	/* Initialize the list of destination pages */
143 	INIT_LIST_HEAD(&image->dest_pages);
144 
145 	/* Initialize the list of unuseable pages */
146 	INIT_LIST_HEAD(&image->unuseable_pages);
147 
148 	/* Read in the segments */
149 	image->nr_segments = nr_segments;
150 	segment_bytes = nr_segments * sizeof(*segments);
151 	result = copy_from_user(image->segment, segments, segment_bytes);
152 	if (result)
153 		goto out;
154 
155 	/*
156 	 * Verify we have good destination addresses.  The caller is
157 	 * responsible for making certain we don't attempt to load
158 	 * the new image into invalid or reserved areas of RAM.  This
159 	 * just verifies it is an address we can use.
160 	 *
161 	 * Since the kernel does everything in page size chunks ensure
162 	 * the destination addreses are page aligned.  Too many
163 	 * special cases crop of when we don't do this.  The most
164 	 * insidious is getting overlapping destination addresses
165 	 * simply because addresses are changed to page size
166 	 * granularity.
167 	 */
168 	result = -EADDRNOTAVAIL;
169 	for (i = 0; i < nr_segments; i++) {
170 		unsigned long mstart, mend;
171 
172 		mstart = image->segment[i].mem;
173 		mend   = mstart + image->segment[i].memsz;
174 		if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
175 			goto out;
176 		if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
177 			goto out;
178 	}
179 
180 	/* Verify our destination addresses do not overlap.
181 	 * If we alloed overlapping destination addresses
182 	 * through very weird things can happen with no
183 	 * easy explanation as one segment stops on another.
184 	 */
185 	result = -EINVAL;
186 	for (i = 0; i < nr_segments; i++) {
187 		unsigned long mstart, mend;
188 		unsigned long j;
189 
190 		mstart = image->segment[i].mem;
191 		mend   = mstart + image->segment[i].memsz;
192 		for (j = 0; j < i; j++) {
193 			unsigned long pstart, pend;
194 			pstart = image->segment[j].mem;
195 			pend   = pstart + image->segment[j].memsz;
196 			/* Do the segments overlap ? */
197 			if ((mend > pstart) && (mstart < pend))
198 				goto out;
199 		}
200 	}
201 
202 	/* Ensure our buffer sizes are strictly less than
203 	 * our memory sizes.  This should always be the case,
204 	 * and it is easier to check up front than to be surprised
205 	 * later on.
206 	 */
207 	result = -EINVAL;
208 	for (i = 0; i < nr_segments; i++) {
209 		if (image->segment[i].bufsz > image->segment[i].memsz)
210 			goto out;
211 	}
212 
213 	result = 0;
214 out:
215 	if (result == 0)
216 		*rimage = image;
217 	else
218 		kfree(image);
219 
220 	return result;
221 
222 }
223 
224 static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
225 				unsigned long nr_segments,
226 				struct kexec_segment __user *segments)
227 {
228 	int result;
229 	struct kimage *image;
230 
231 	/* Allocate and initialize a controlling structure */
232 	image = NULL;
233 	result = do_kimage_alloc(&image, entry, nr_segments, segments);
234 	if (result)
235 		goto out;
236 
237 	*rimage = image;
238 
239 	/*
240 	 * Find a location for the control code buffer, and add it
241 	 * the vector of segments so that it's pages will also be
242 	 * counted as destination pages.
243 	 */
244 	result = -ENOMEM;
245 	image->control_code_page = kimage_alloc_control_pages(image,
246 					   get_order(KEXEC_CONTROL_PAGE_SIZE));
247 	if (!image->control_code_page) {
248 		printk(KERN_ERR "Could not allocate control_code_buffer\n");
249 		goto out;
250 	}
251 
252 	image->swap_page = kimage_alloc_control_pages(image, 0);
253 	if (!image->swap_page) {
254 		printk(KERN_ERR "Could not allocate swap buffer\n");
255 		goto out;
256 	}
257 
258 	result = 0;
259  out:
260 	if (result == 0)
261 		*rimage = image;
262 	else
263 		kfree(image);
264 
265 	return result;
266 }
267 
268 static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
269 				unsigned long nr_segments,
270 				struct kexec_segment __user *segments)
271 {
272 	int result;
273 	struct kimage *image;
274 	unsigned long i;
275 
276 	image = NULL;
277 	/* Verify we have a valid entry point */
278 	if ((entry < crashk_res.start) || (entry > crashk_res.end)) {
279 		result = -EADDRNOTAVAIL;
280 		goto out;
281 	}
282 
283 	/* Allocate and initialize a controlling structure */
284 	result = do_kimage_alloc(&image, entry, nr_segments, segments);
285 	if (result)
286 		goto out;
287 
288 	/* Enable the special crash kernel control page
289 	 * allocation policy.
290 	 */
291 	image->control_page = crashk_res.start;
292 	image->type = KEXEC_TYPE_CRASH;
293 
294 	/*
295 	 * Verify we have good destination addresses.  Normally
296 	 * the caller is responsible for making certain we don't
297 	 * attempt to load the new image into invalid or reserved
298 	 * areas of RAM.  But crash kernels are preloaded into a
299 	 * reserved area of ram.  We must ensure the addresses
300 	 * are in the reserved area otherwise preloading the
301 	 * kernel could corrupt things.
302 	 */
303 	result = -EADDRNOTAVAIL;
304 	for (i = 0; i < nr_segments; i++) {
305 		unsigned long mstart, mend;
306 
307 		mstart = image->segment[i].mem;
308 		mend = mstart + image->segment[i].memsz - 1;
309 		/* Ensure we are within the crash kernel limits */
310 		if ((mstart < crashk_res.start) || (mend > crashk_res.end))
311 			goto out;
312 	}
313 
314 	/*
315 	 * Find a location for the control code buffer, and add
316 	 * the vector of segments so that it's pages will also be
317 	 * counted as destination pages.
318 	 */
319 	result = -ENOMEM;
320 	image->control_code_page = kimage_alloc_control_pages(image,
321 					   get_order(KEXEC_CONTROL_PAGE_SIZE));
322 	if (!image->control_code_page) {
323 		printk(KERN_ERR "Could not allocate control_code_buffer\n");
324 		goto out;
325 	}
326 
327 	result = 0;
328 out:
329 	if (result == 0)
330 		*rimage = image;
331 	else
332 		kfree(image);
333 
334 	return result;
335 }
336 
337 static int kimage_is_destination_range(struct kimage *image,
338 					unsigned long start,
339 					unsigned long end)
340 {
341 	unsigned long i;
342 
343 	for (i = 0; i < image->nr_segments; i++) {
344 		unsigned long mstart, mend;
345 
346 		mstart = image->segment[i].mem;
347 		mend = mstart + image->segment[i].memsz;
348 		if ((end > mstart) && (start < mend))
349 			return 1;
350 	}
351 
352 	return 0;
353 }
354 
355 static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
356 {
357 	struct page *pages;
358 
359 	pages = alloc_pages(gfp_mask, order);
360 	if (pages) {
361 		unsigned int count, i;
362 		pages->mapping = NULL;
363 		set_page_private(pages, order);
364 		count = 1 << order;
365 		for (i = 0; i < count; i++)
366 			SetPageReserved(pages + i);
367 	}
368 
369 	return pages;
370 }
371 
372 static void kimage_free_pages(struct page *page)
373 {
374 	unsigned int order, count, i;
375 
376 	order = page_private(page);
377 	count = 1 << order;
378 	for (i = 0; i < count; i++)
379 		ClearPageReserved(page + i);
380 	__free_pages(page, order);
381 }
382 
383 static void kimage_free_page_list(struct list_head *list)
384 {
385 	struct list_head *pos, *next;
386 
387 	list_for_each_safe(pos, next, list) {
388 		struct page *page;
389 
390 		page = list_entry(pos, struct page, lru);
391 		list_del(&page->lru);
392 		kimage_free_pages(page);
393 	}
394 }
395 
396 static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
397 							unsigned int order)
398 {
399 	/* Control pages are special, they are the intermediaries
400 	 * that are needed while we copy the rest of the pages
401 	 * to their final resting place.  As such they must
402 	 * not conflict with either the destination addresses
403 	 * or memory the kernel is already using.
404 	 *
405 	 * The only case where we really need more than one of
406 	 * these are for architectures where we cannot disable
407 	 * the MMU and must instead generate an identity mapped
408 	 * page table for all of the memory.
409 	 *
410 	 * At worst this runs in O(N) of the image size.
411 	 */
412 	struct list_head extra_pages;
413 	struct page *pages;
414 	unsigned int count;
415 
416 	count = 1 << order;
417 	INIT_LIST_HEAD(&extra_pages);
418 
419 	/* Loop while I can allocate a page and the page allocated
420 	 * is a destination page.
421 	 */
422 	do {
423 		unsigned long pfn, epfn, addr, eaddr;
424 
425 		pages = kimage_alloc_pages(GFP_KERNEL, order);
426 		if (!pages)
427 			break;
428 		pfn   = page_to_pfn(pages);
429 		epfn  = pfn + count;
430 		addr  = pfn << PAGE_SHIFT;
431 		eaddr = epfn << PAGE_SHIFT;
432 		if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
433 			      kimage_is_destination_range(image, addr, eaddr)) {
434 			list_add(&pages->lru, &extra_pages);
435 			pages = NULL;
436 		}
437 	} while (!pages);
438 
439 	if (pages) {
440 		/* Remember the allocated page... */
441 		list_add(&pages->lru, &image->control_pages);
442 
443 		/* Because the page is already in it's destination
444 		 * location we will never allocate another page at
445 		 * that address.  Therefore kimage_alloc_pages
446 		 * will not return it (again) and we don't need
447 		 * to give it an entry in image->segment[].
448 		 */
449 	}
450 	/* Deal with the destination pages I have inadvertently allocated.
451 	 *
452 	 * Ideally I would convert multi-page allocations into single
453 	 * page allocations, and add everyting to image->dest_pages.
454 	 *
455 	 * For now it is simpler to just free the pages.
456 	 */
457 	kimage_free_page_list(&extra_pages);
458 
459 	return pages;
460 }
461 
462 static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
463 						      unsigned int order)
464 {
465 	/* Control pages are special, they are the intermediaries
466 	 * that are needed while we copy the rest of the pages
467 	 * to their final resting place.  As such they must
468 	 * not conflict with either the destination addresses
469 	 * or memory the kernel is already using.
470 	 *
471 	 * Control pages are also the only pags we must allocate
472 	 * when loading a crash kernel.  All of the other pages
473 	 * are specified by the segments and we just memcpy
474 	 * into them directly.
475 	 *
476 	 * The only case where we really need more than one of
477 	 * these are for architectures where we cannot disable
478 	 * the MMU and must instead generate an identity mapped
479 	 * page table for all of the memory.
480 	 *
481 	 * Given the low demand this implements a very simple
482 	 * allocator that finds the first hole of the appropriate
483 	 * size in the reserved memory region, and allocates all
484 	 * of the memory up to and including the hole.
485 	 */
486 	unsigned long hole_start, hole_end, size;
487 	struct page *pages;
488 
489 	pages = NULL;
490 	size = (1 << order) << PAGE_SHIFT;
491 	hole_start = (image->control_page + (size - 1)) & ~(size - 1);
492 	hole_end   = hole_start + size - 1;
493 	while (hole_end <= crashk_res.end) {
494 		unsigned long i;
495 
496 		if (hole_end > KEXEC_CONTROL_MEMORY_LIMIT)
497 			break;
498 		if (hole_end > crashk_res.end)
499 			break;
500 		/* See if I overlap any of the segments */
501 		for (i = 0; i < image->nr_segments; i++) {
502 			unsigned long mstart, mend;
503 
504 			mstart = image->segment[i].mem;
505 			mend   = mstart + image->segment[i].memsz - 1;
506 			if ((hole_end >= mstart) && (hole_start <= mend)) {
507 				/* Advance the hole to the end of the segment */
508 				hole_start = (mend + (size - 1)) & ~(size - 1);
509 				hole_end   = hole_start + size - 1;
510 				break;
511 			}
512 		}
513 		/* If I don't overlap any segments I have found my hole! */
514 		if (i == image->nr_segments) {
515 			pages = pfn_to_page(hole_start >> PAGE_SHIFT);
516 			break;
517 		}
518 	}
519 	if (pages)
520 		image->control_page = hole_end;
521 
522 	return pages;
523 }
524 
525 
526 struct page *kimage_alloc_control_pages(struct kimage *image,
527 					 unsigned int order)
528 {
529 	struct page *pages = NULL;
530 
531 	switch (image->type) {
532 	case KEXEC_TYPE_DEFAULT:
533 		pages = kimage_alloc_normal_control_pages(image, order);
534 		break;
535 	case KEXEC_TYPE_CRASH:
536 		pages = kimage_alloc_crash_control_pages(image, order);
537 		break;
538 	}
539 
540 	return pages;
541 }
542 
543 static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
544 {
545 	if (*image->entry != 0)
546 		image->entry++;
547 
548 	if (image->entry == image->last_entry) {
549 		kimage_entry_t *ind_page;
550 		struct page *page;
551 
552 		page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
553 		if (!page)
554 			return -ENOMEM;
555 
556 		ind_page = page_address(page);
557 		*image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
558 		image->entry = ind_page;
559 		image->last_entry = ind_page +
560 				      ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
561 	}
562 	*image->entry = entry;
563 	image->entry++;
564 	*image->entry = 0;
565 
566 	return 0;
567 }
568 
569 static int kimage_set_destination(struct kimage *image,
570 				   unsigned long destination)
571 {
572 	int result;
573 
574 	destination &= PAGE_MASK;
575 	result = kimage_add_entry(image, destination | IND_DESTINATION);
576 	if (result == 0)
577 		image->destination = destination;
578 
579 	return result;
580 }
581 
582 
583 static int kimage_add_page(struct kimage *image, unsigned long page)
584 {
585 	int result;
586 
587 	page &= PAGE_MASK;
588 	result = kimage_add_entry(image, page | IND_SOURCE);
589 	if (result == 0)
590 		image->destination += PAGE_SIZE;
591 
592 	return result;
593 }
594 
595 
596 static void kimage_free_extra_pages(struct kimage *image)
597 {
598 	/* Walk through and free any extra destination pages I may have */
599 	kimage_free_page_list(&image->dest_pages);
600 
601 	/* Walk through and free any unuseable pages I have cached */
602 	kimage_free_page_list(&image->unuseable_pages);
603 
604 }
605 static void kimage_terminate(struct kimage *image)
606 {
607 	if (*image->entry != 0)
608 		image->entry++;
609 
610 	*image->entry = IND_DONE;
611 }
612 
613 #define for_each_kimage_entry(image, ptr, entry) \
614 	for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
615 		ptr = (entry & IND_INDIRECTION)? \
616 			phys_to_virt((entry & PAGE_MASK)): ptr +1)
617 
618 static void kimage_free_entry(kimage_entry_t entry)
619 {
620 	struct page *page;
621 
622 	page = pfn_to_page(entry >> PAGE_SHIFT);
623 	kimage_free_pages(page);
624 }
625 
626 static void kimage_free(struct kimage *image)
627 {
628 	kimage_entry_t *ptr, entry;
629 	kimage_entry_t ind = 0;
630 
631 	if (!image)
632 		return;
633 
634 	kimage_free_extra_pages(image);
635 	for_each_kimage_entry(image, ptr, entry) {
636 		if (entry & IND_INDIRECTION) {
637 			/* Free the previous indirection page */
638 			if (ind & IND_INDIRECTION)
639 				kimage_free_entry(ind);
640 			/* Save this indirection page until we are
641 			 * done with it.
642 			 */
643 			ind = entry;
644 		}
645 		else if (entry & IND_SOURCE)
646 			kimage_free_entry(entry);
647 	}
648 	/* Free the final indirection page */
649 	if (ind & IND_INDIRECTION)
650 		kimage_free_entry(ind);
651 
652 	/* Handle any machine specific cleanup */
653 	machine_kexec_cleanup(image);
654 
655 	/* Free the kexec control pages... */
656 	kimage_free_page_list(&image->control_pages);
657 	kfree(image);
658 }
659 
660 static kimage_entry_t *kimage_dst_used(struct kimage *image,
661 					unsigned long page)
662 {
663 	kimage_entry_t *ptr, entry;
664 	unsigned long destination = 0;
665 
666 	for_each_kimage_entry(image, ptr, entry) {
667 		if (entry & IND_DESTINATION)
668 			destination = entry & PAGE_MASK;
669 		else if (entry & IND_SOURCE) {
670 			if (page == destination)
671 				return ptr;
672 			destination += PAGE_SIZE;
673 		}
674 	}
675 
676 	return NULL;
677 }
678 
679 static struct page *kimage_alloc_page(struct kimage *image,
680 					gfp_t gfp_mask,
681 					unsigned long destination)
682 {
683 	/*
684 	 * Here we implement safeguards to ensure that a source page
685 	 * is not copied to its destination page before the data on
686 	 * the destination page is no longer useful.
687 	 *
688 	 * To do this we maintain the invariant that a source page is
689 	 * either its own destination page, or it is not a
690 	 * destination page at all.
691 	 *
692 	 * That is slightly stronger than required, but the proof
693 	 * that no problems will not occur is trivial, and the
694 	 * implementation is simply to verify.
695 	 *
696 	 * When allocating all pages normally this algorithm will run
697 	 * in O(N) time, but in the worst case it will run in O(N^2)
698 	 * time.   If the runtime is a problem the data structures can
699 	 * be fixed.
700 	 */
701 	struct page *page;
702 	unsigned long addr;
703 
704 	/*
705 	 * Walk through the list of destination pages, and see if I
706 	 * have a match.
707 	 */
708 	list_for_each_entry(page, &image->dest_pages, lru) {
709 		addr = page_to_pfn(page) << PAGE_SHIFT;
710 		if (addr == destination) {
711 			list_del(&page->lru);
712 			return page;
713 		}
714 	}
715 	page = NULL;
716 	while (1) {
717 		kimage_entry_t *old;
718 
719 		/* Allocate a page, if we run out of memory give up */
720 		page = kimage_alloc_pages(gfp_mask, 0);
721 		if (!page)
722 			return NULL;
723 		/* If the page cannot be used file it away */
724 		if (page_to_pfn(page) >
725 				(KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
726 			list_add(&page->lru, &image->unuseable_pages);
727 			continue;
728 		}
729 		addr = page_to_pfn(page) << PAGE_SHIFT;
730 
731 		/* If it is the destination page we want use it */
732 		if (addr == destination)
733 			break;
734 
735 		/* If the page is not a destination page use it */
736 		if (!kimage_is_destination_range(image, addr,
737 						  addr + PAGE_SIZE))
738 			break;
739 
740 		/*
741 		 * I know that the page is someones destination page.
742 		 * See if there is already a source page for this
743 		 * destination page.  And if so swap the source pages.
744 		 */
745 		old = kimage_dst_used(image, addr);
746 		if (old) {
747 			/* If so move it */
748 			unsigned long old_addr;
749 			struct page *old_page;
750 
751 			old_addr = *old & PAGE_MASK;
752 			old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
753 			copy_highpage(page, old_page);
754 			*old = addr | (*old & ~PAGE_MASK);
755 
756 			/* The old page I have found cannot be a
757 			 * destination page, so return it if it's
758 			 * gfp_flags honor the ones passed in.
759 			 */
760 			if (!(gfp_mask & __GFP_HIGHMEM) &&
761 			    PageHighMem(old_page)) {
762 				kimage_free_pages(old_page);
763 				continue;
764 			}
765 			addr = old_addr;
766 			page = old_page;
767 			break;
768 		}
769 		else {
770 			/* Place the page on the destination list I
771 			 * will use it later.
772 			 */
773 			list_add(&page->lru, &image->dest_pages);
774 		}
775 	}
776 
777 	return page;
778 }
779 
780 static int kimage_load_normal_segment(struct kimage *image,
781 					 struct kexec_segment *segment)
782 {
783 	unsigned long maddr;
784 	unsigned long ubytes, mbytes;
785 	int result;
786 	unsigned char __user *buf;
787 
788 	result = 0;
789 	buf = segment->buf;
790 	ubytes = segment->bufsz;
791 	mbytes = segment->memsz;
792 	maddr = segment->mem;
793 
794 	result = kimage_set_destination(image, maddr);
795 	if (result < 0)
796 		goto out;
797 
798 	while (mbytes) {
799 		struct page *page;
800 		char *ptr;
801 		size_t uchunk, mchunk;
802 
803 		page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
804 		if (!page) {
805 			result  = -ENOMEM;
806 			goto out;
807 		}
808 		result = kimage_add_page(image, page_to_pfn(page)
809 								<< PAGE_SHIFT);
810 		if (result < 0)
811 			goto out;
812 
813 		ptr = kmap(page);
814 		/* Start with a clear page */
815 		memset(ptr, 0, PAGE_SIZE);
816 		ptr += maddr & ~PAGE_MASK;
817 		mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
818 		if (mchunk > mbytes)
819 			mchunk = mbytes;
820 
821 		uchunk = mchunk;
822 		if (uchunk > ubytes)
823 			uchunk = ubytes;
824 
825 		result = copy_from_user(ptr, buf, uchunk);
826 		kunmap(page);
827 		if (result) {
828 			result = (result < 0) ? result : -EIO;
829 			goto out;
830 		}
831 		ubytes -= uchunk;
832 		maddr  += mchunk;
833 		buf    += mchunk;
834 		mbytes -= mchunk;
835 	}
836 out:
837 	return result;
838 }
839 
840 static int kimage_load_crash_segment(struct kimage *image,
841 					struct kexec_segment *segment)
842 {
843 	/* For crash dumps kernels we simply copy the data from
844 	 * user space to it's destination.
845 	 * We do things a page at a time for the sake of kmap.
846 	 */
847 	unsigned long maddr;
848 	unsigned long ubytes, mbytes;
849 	int result;
850 	unsigned char __user *buf;
851 
852 	result = 0;
853 	buf = segment->buf;
854 	ubytes = segment->bufsz;
855 	mbytes = segment->memsz;
856 	maddr = segment->mem;
857 	while (mbytes) {
858 		struct page *page;
859 		char *ptr;
860 		size_t uchunk, mchunk;
861 
862 		page = pfn_to_page(maddr >> PAGE_SHIFT);
863 		if (!page) {
864 			result  = -ENOMEM;
865 			goto out;
866 		}
867 		ptr = kmap(page);
868 		ptr += maddr & ~PAGE_MASK;
869 		mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
870 		if (mchunk > mbytes)
871 			mchunk = mbytes;
872 
873 		uchunk = mchunk;
874 		if (uchunk > ubytes) {
875 			uchunk = ubytes;
876 			/* Zero the trailing part of the page */
877 			memset(ptr + uchunk, 0, mchunk - uchunk);
878 		}
879 		result = copy_from_user(ptr, buf, uchunk);
880 		kexec_flush_icache_page(page);
881 		kunmap(page);
882 		if (result) {
883 			result = (result < 0) ? result : -EIO;
884 			goto out;
885 		}
886 		ubytes -= uchunk;
887 		maddr  += mchunk;
888 		buf    += mchunk;
889 		mbytes -= mchunk;
890 	}
891 out:
892 	return result;
893 }
894 
895 static int kimage_load_segment(struct kimage *image,
896 				struct kexec_segment *segment)
897 {
898 	int result = -ENOMEM;
899 
900 	switch (image->type) {
901 	case KEXEC_TYPE_DEFAULT:
902 		result = kimage_load_normal_segment(image, segment);
903 		break;
904 	case KEXEC_TYPE_CRASH:
905 		result = kimage_load_crash_segment(image, segment);
906 		break;
907 	}
908 
909 	return result;
910 }
911 
912 /*
913  * Exec Kernel system call: for obvious reasons only root may call it.
914  *
915  * This call breaks up into three pieces.
916  * - A generic part which loads the new kernel from the current
917  *   address space, and very carefully places the data in the
918  *   allocated pages.
919  *
920  * - A generic part that interacts with the kernel and tells all of
921  *   the devices to shut down.  Preventing on-going dmas, and placing
922  *   the devices in a consistent state so a later kernel can
923  *   reinitialize them.
924  *
925  * - A machine specific part that includes the syscall number
926  *   and the copies the image to it's final destination.  And
927  *   jumps into the image at entry.
928  *
929  * kexec does not sync, or unmount filesystems so if you need
930  * that to happen you need to do that yourself.
931  */
932 struct kimage *kexec_image;
933 struct kimage *kexec_crash_image;
934 
935 static DEFINE_MUTEX(kexec_mutex);
936 
937 SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
938 		struct kexec_segment __user *, segments, unsigned long, flags)
939 {
940 	struct kimage **dest_image, *image;
941 	int result;
942 
943 	/* We only trust the superuser with rebooting the system. */
944 	if (!capable(CAP_SYS_BOOT))
945 		return -EPERM;
946 
947 	/*
948 	 * Verify we have a legal set of flags
949 	 * This leaves us room for future extensions.
950 	 */
951 	if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
952 		return -EINVAL;
953 
954 	/* Verify we are on the appropriate architecture */
955 	if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
956 		((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
957 		return -EINVAL;
958 
959 	/* Put an artificial cap on the number
960 	 * of segments passed to kexec_load.
961 	 */
962 	if (nr_segments > KEXEC_SEGMENT_MAX)
963 		return -EINVAL;
964 
965 	image = NULL;
966 	result = 0;
967 
968 	/* Because we write directly to the reserved memory
969 	 * region when loading crash kernels we need a mutex here to
970 	 * prevent multiple crash  kernels from attempting to load
971 	 * simultaneously, and to prevent a crash kernel from loading
972 	 * over the top of a in use crash kernel.
973 	 *
974 	 * KISS: always take the mutex.
975 	 */
976 	if (!mutex_trylock(&kexec_mutex))
977 		return -EBUSY;
978 
979 	dest_image = &kexec_image;
980 	if (flags & KEXEC_ON_CRASH)
981 		dest_image = &kexec_crash_image;
982 	if (nr_segments > 0) {
983 		unsigned long i;
984 
985 		/* Loading another kernel to reboot into */
986 		if ((flags & KEXEC_ON_CRASH) == 0)
987 			result = kimage_normal_alloc(&image, entry,
988 							nr_segments, segments);
989 		/* Loading another kernel to switch to if this one crashes */
990 		else if (flags & KEXEC_ON_CRASH) {
991 			/* Free any current crash dump kernel before
992 			 * we corrupt it.
993 			 */
994 			kimage_free(xchg(&kexec_crash_image, NULL));
995 			result = kimage_crash_alloc(&image, entry,
996 						     nr_segments, segments);
997 		}
998 		if (result)
999 			goto out;
1000 
1001 		if (flags & KEXEC_PRESERVE_CONTEXT)
1002 			image->preserve_context = 1;
1003 		result = machine_kexec_prepare(image);
1004 		if (result)
1005 			goto out;
1006 
1007 		for (i = 0; i < nr_segments; i++) {
1008 			result = kimage_load_segment(image, &image->segment[i]);
1009 			if (result)
1010 				goto out;
1011 		}
1012 		kimage_terminate(image);
1013 	}
1014 	/* Install the new kernel, and  Uninstall the old */
1015 	image = xchg(dest_image, image);
1016 
1017 out:
1018 	mutex_unlock(&kexec_mutex);
1019 	kimage_free(image);
1020 
1021 	return result;
1022 }
1023 
1024 #ifdef CONFIG_COMPAT
1025 asmlinkage long compat_sys_kexec_load(unsigned long entry,
1026 				unsigned long nr_segments,
1027 				struct compat_kexec_segment __user *segments,
1028 				unsigned long flags)
1029 {
1030 	struct compat_kexec_segment in;
1031 	struct kexec_segment out, __user *ksegments;
1032 	unsigned long i, result;
1033 
1034 	/* Don't allow clients that don't understand the native
1035 	 * architecture to do anything.
1036 	 */
1037 	if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
1038 		return -EINVAL;
1039 
1040 	if (nr_segments > KEXEC_SEGMENT_MAX)
1041 		return -EINVAL;
1042 
1043 	ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
1044 	for (i=0; i < nr_segments; i++) {
1045 		result = copy_from_user(&in, &segments[i], sizeof(in));
1046 		if (result)
1047 			return -EFAULT;
1048 
1049 		out.buf   = compat_ptr(in.buf);
1050 		out.bufsz = in.bufsz;
1051 		out.mem   = in.mem;
1052 		out.memsz = in.memsz;
1053 
1054 		result = copy_to_user(&ksegments[i], &out, sizeof(out));
1055 		if (result)
1056 			return -EFAULT;
1057 	}
1058 
1059 	return sys_kexec_load(entry, nr_segments, ksegments, flags);
1060 }
1061 #endif
1062 
1063 void crash_kexec(struct pt_regs *regs)
1064 {
1065 	/* Take the kexec_mutex here to prevent sys_kexec_load
1066 	 * running on one cpu from replacing the crash kernel
1067 	 * we are using after a panic on a different cpu.
1068 	 *
1069 	 * If the crash kernel was not located in a fixed area
1070 	 * of memory the xchg(&kexec_crash_image) would be
1071 	 * sufficient.  But since I reuse the memory...
1072 	 */
1073 	if (mutex_trylock(&kexec_mutex)) {
1074 		if (kexec_crash_image) {
1075 			struct pt_regs fixed_regs;
1076 			crash_setup_regs(&fixed_regs, regs);
1077 			crash_save_vmcoreinfo();
1078 			machine_crash_shutdown(&fixed_regs);
1079 			machine_kexec(kexec_crash_image);
1080 		}
1081 		mutex_unlock(&kexec_mutex);
1082 	}
1083 }
1084 
1085 static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
1086 			    size_t data_len)
1087 {
1088 	struct elf_note note;
1089 
1090 	note.n_namesz = strlen(name) + 1;
1091 	note.n_descsz = data_len;
1092 	note.n_type   = type;
1093 	memcpy(buf, &note, sizeof(note));
1094 	buf += (sizeof(note) + 3)/4;
1095 	memcpy(buf, name, note.n_namesz);
1096 	buf += (note.n_namesz + 3)/4;
1097 	memcpy(buf, data, note.n_descsz);
1098 	buf += (note.n_descsz + 3)/4;
1099 
1100 	return buf;
1101 }
1102 
1103 static void final_note(u32 *buf)
1104 {
1105 	struct elf_note note;
1106 
1107 	note.n_namesz = 0;
1108 	note.n_descsz = 0;
1109 	note.n_type   = 0;
1110 	memcpy(buf, &note, sizeof(note));
1111 }
1112 
1113 void crash_save_cpu(struct pt_regs *regs, int cpu)
1114 {
1115 	struct elf_prstatus prstatus;
1116 	u32 *buf;
1117 
1118 	if ((cpu < 0) || (cpu >= nr_cpu_ids))
1119 		return;
1120 
1121 	/* Using ELF notes here is opportunistic.
1122 	 * I need a well defined structure format
1123 	 * for the data I pass, and I need tags
1124 	 * on the data to indicate what information I have
1125 	 * squirrelled away.  ELF notes happen to provide
1126 	 * all of that, so there is no need to invent something new.
1127 	 */
1128 	buf = (u32*)per_cpu_ptr(crash_notes, cpu);
1129 	if (!buf)
1130 		return;
1131 	memset(&prstatus, 0, sizeof(prstatus));
1132 	prstatus.pr_pid = current->pid;
1133 	elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
1134 	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
1135 		      	      &prstatus, sizeof(prstatus));
1136 	final_note(buf);
1137 }
1138 
1139 static int __init crash_notes_memory_init(void)
1140 {
1141 	/* Allocate memory for saving cpu registers. */
1142 	crash_notes = alloc_percpu(note_buf_t);
1143 	if (!crash_notes) {
1144 		printk("Kexec: Memory allocation for saving cpu register"
1145 		" states failed\n");
1146 		return -ENOMEM;
1147 	}
1148 	return 0;
1149 }
1150 module_init(crash_notes_memory_init)
1151 
1152 
1153 /*
1154  * parsing the "crashkernel" commandline
1155  *
1156  * this code is intended to be called from architecture specific code
1157  */
1158 
1159 
1160 /*
1161  * This function parses command lines in the format
1162  *
1163  *   crashkernel=ramsize-range:size[,...][@offset]
1164  *
1165  * The function returns 0 on success and -EINVAL on failure.
1166  */
1167 static int __init parse_crashkernel_mem(char 			*cmdline,
1168 					unsigned long long	system_ram,
1169 					unsigned long long	*crash_size,
1170 					unsigned long long	*crash_base)
1171 {
1172 	char *cur = cmdline, *tmp;
1173 
1174 	/* for each entry of the comma-separated list */
1175 	do {
1176 		unsigned long long start, end = ULLONG_MAX, size;
1177 
1178 		/* get the start of the range */
1179 		start = memparse(cur, &tmp);
1180 		if (cur == tmp) {
1181 			pr_warning("crashkernel: Memory value expected\n");
1182 			return -EINVAL;
1183 		}
1184 		cur = tmp;
1185 		if (*cur != '-') {
1186 			pr_warning("crashkernel: '-' expected\n");
1187 			return -EINVAL;
1188 		}
1189 		cur++;
1190 
1191 		/* if no ':' is here, than we read the end */
1192 		if (*cur != ':') {
1193 			end = memparse(cur, &tmp);
1194 			if (cur == tmp) {
1195 				pr_warning("crashkernel: Memory "
1196 						"value expected\n");
1197 				return -EINVAL;
1198 			}
1199 			cur = tmp;
1200 			if (end <= start) {
1201 				pr_warning("crashkernel: end <= start\n");
1202 				return -EINVAL;
1203 			}
1204 		}
1205 
1206 		if (*cur != ':') {
1207 			pr_warning("crashkernel: ':' expected\n");
1208 			return -EINVAL;
1209 		}
1210 		cur++;
1211 
1212 		size = memparse(cur, &tmp);
1213 		if (cur == tmp) {
1214 			pr_warning("Memory value expected\n");
1215 			return -EINVAL;
1216 		}
1217 		cur = tmp;
1218 		if (size >= system_ram) {
1219 			pr_warning("crashkernel: invalid size\n");
1220 			return -EINVAL;
1221 		}
1222 
1223 		/* match ? */
1224 		if (system_ram >= start && system_ram < end) {
1225 			*crash_size = size;
1226 			break;
1227 		}
1228 	} while (*cur++ == ',');
1229 
1230 	if (*crash_size > 0) {
1231 		while (*cur && *cur != ' ' && *cur != '@')
1232 			cur++;
1233 		if (*cur == '@') {
1234 			cur++;
1235 			*crash_base = memparse(cur, &tmp);
1236 			if (cur == tmp) {
1237 				pr_warning("Memory value expected "
1238 						"after '@'\n");
1239 				return -EINVAL;
1240 			}
1241 		}
1242 	}
1243 
1244 	return 0;
1245 }
1246 
1247 /*
1248  * That function parses "simple" (old) crashkernel command lines like
1249  *
1250  * 	crashkernel=size[@offset]
1251  *
1252  * It returns 0 on success and -EINVAL on failure.
1253  */
1254 static int __init parse_crashkernel_simple(char 		*cmdline,
1255 					   unsigned long long 	*crash_size,
1256 					   unsigned long long 	*crash_base)
1257 {
1258 	char *cur = cmdline;
1259 
1260 	*crash_size = memparse(cmdline, &cur);
1261 	if (cmdline == cur) {
1262 		pr_warning("crashkernel: memory value expected\n");
1263 		return -EINVAL;
1264 	}
1265 
1266 	if (*cur == '@')
1267 		*crash_base = memparse(cur+1, &cur);
1268 
1269 	return 0;
1270 }
1271 
1272 /*
1273  * That function is the entry point for command line parsing and should be
1274  * called from the arch-specific code.
1275  */
1276 int __init parse_crashkernel(char 		 *cmdline,
1277 			     unsigned long long system_ram,
1278 			     unsigned long long *crash_size,
1279 			     unsigned long long *crash_base)
1280 {
1281 	char 	*p = cmdline, *ck_cmdline = NULL;
1282 	char	*first_colon, *first_space;
1283 
1284 	BUG_ON(!crash_size || !crash_base);
1285 	*crash_size = 0;
1286 	*crash_base = 0;
1287 
1288 	/* find crashkernel and use the last one if there are more */
1289 	p = strstr(p, "crashkernel=");
1290 	while (p) {
1291 		ck_cmdline = p;
1292 		p = strstr(p+1, "crashkernel=");
1293 	}
1294 
1295 	if (!ck_cmdline)
1296 		return -EINVAL;
1297 
1298 	ck_cmdline += 12; /* strlen("crashkernel=") */
1299 
1300 	/*
1301 	 * if the commandline contains a ':', then that's the extended
1302 	 * syntax -- if not, it must be the classic syntax
1303 	 */
1304 	first_colon = strchr(ck_cmdline, ':');
1305 	first_space = strchr(ck_cmdline, ' ');
1306 	if (first_colon && (!first_space || first_colon < first_space))
1307 		return parse_crashkernel_mem(ck_cmdline, system_ram,
1308 				crash_size, crash_base);
1309 	else
1310 		return parse_crashkernel_simple(ck_cmdline, crash_size,
1311 				crash_base);
1312 
1313 	return 0;
1314 }
1315 
1316 
1317 
1318 void crash_save_vmcoreinfo(void)
1319 {
1320 	u32 *buf;
1321 
1322 	if (!vmcoreinfo_size)
1323 		return;
1324 
1325 	vmcoreinfo_append_str("CRASHTIME=%ld", get_seconds());
1326 
1327 	buf = (u32 *)vmcoreinfo_note;
1328 
1329 	buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
1330 			      vmcoreinfo_size);
1331 
1332 	final_note(buf);
1333 }
1334 
1335 void vmcoreinfo_append_str(const char *fmt, ...)
1336 {
1337 	va_list args;
1338 	char buf[0x50];
1339 	int r;
1340 
1341 	va_start(args, fmt);
1342 	r = vsnprintf(buf, sizeof(buf), fmt, args);
1343 	va_end(args);
1344 
1345 	if (r + vmcoreinfo_size > vmcoreinfo_max_size)
1346 		r = vmcoreinfo_max_size - vmcoreinfo_size;
1347 
1348 	memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
1349 
1350 	vmcoreinfo_size += r;
1351 }
1352 
1353 /*
1354  * provide an empty default implementation here -- architecture
1355  * code may override this
1356  */
1357 void __attribute__ ((weak)) arch_crash_save_vmcoreinfo(void)
1358 {}
1359 
1360 unsigned long __attribute__ ((weak)) paddr_vmcoreinfo_note(void)
1361 {
1362 	return __pa((unsigned long)(char *)&vmcoreinfo_note);
1363 }
1364 
1365 static int __init crash_save_vmcoreinfo_init(void)
1366 {
1367 	VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
1368 	VMCOREINFO_PAGESIZE(PAGE_SIZE);
1369 
1370 	VMCOREINFO_SYMBOL(init_uts_ns);
1371 	VMCOREINFO_SYMBOL(node_online_map);
1372 	VMCOREINFO_SYMBOL(swapper_pg_dir);
1373 	VMCOREINFO_SYMBOL(_stext);
1374 	VMCOREINFO_SYMBOL(vmlist);
1375 
1376 #ifndef CONFIG_NEED_MULTIPLE_NODES
1377 	VMCOREINFO_SYMBOL(mem_map);
1378 	VMCOREINFO_SYMBOL(contig_page_data);
1379 #endif
1380 #ifdef CONFIG_SPARSEMEM
1381 	VMCOREINFO_SYMBOL(mem_section);
1382 	VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
1383 	VMCOREINFO_STRUCT_SIZE(mem_section);
1384 	VMCOREINFO_OFFSET(mem_section, section_mem_map);
1385 #endif
1386 	VMCOREINFO_STRUCT_SIZE(page);
1387 	VMCOREINFO_STRUCT_SIZE(pglist_data);
1388 	VMCOREINFO_STRUCT_SIZE(zone);
1389 	VMCOREINFO_STRUCT_SIZE(free_area);
1390 	VMCOREINFO_STRUCT_SIZE(list_head);
1391 	VMCOREINFO_SIZE(nodemask_t);
1392 	VMCOREINFO_OFFSET(page, flags);
1393 	VMCOREINFO_OFFSET(page, _count);
1394 	VMCOREINFO_OFFSET(page, mapping);
1395 	VMCOREINFO_OFFSET(page, lru);
1396 	VMCOREINFO_OFFSET(pglist_data, node_zones);
1397 	VMCOREINFO_OFFSET(pglist_data, nr_zones);
1398 #ifdef CONFIG_FLAT_NODE_MEM_MAP
1399 	VMCOREINFO_OFFSET(pglist_data, node_mem_map);
1400 #endif
1401 	VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
1402 	VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
1403 	VMCOREINFO_OFFSET(pglist_data, node_id);
1404 	VMCOREINFO_OFFSET(zone, free_area);
1405 	VMCOREINFO_OFFSET(zone, vm_stat);
1406 	VMCOREINFO_OFFSET(zone, spanned_pages);
1407 	VMCOREINFO_OFFSET(free_area, free_list);
1408 	VMCOREINFO_OFFSET(list_head, next);
1409 	VMCOREINFO_OFFSET(list_head, prev);
1410 	VMCOREINFO_OFFSET(vm_struct, addr);
1411 	VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
1412 	log_buf_kexec_setup();
1413 	VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
1414 	VMCOREINFO_NUMBER(NR_FREE_PAGES);
1415 	VMCOREINFO_NUMBER(PG_lru);
1416 	VMCOREINFO_NUMBER(PG_private);
1417 	VMCOREINFO_NUMBER(PG_swapcache);
1418 
1419 	arch_crash_save_vmcoreinfo();
1420 
1421 	return 0;
1422 }
1423 
1424 module_init(crash_save_vmcoreinfo_init)
1425 
1426 /*
1427  * Move into place and start executing a preloaded standalone
1428  * executable.  If nothing was preloaded return an error.
1429  */
1430 int kernel_kexec(void)
1431 {
1432 	int error = 0;
1433 
1434 	if (!mutex_trylock(&kexec_mutex))
1435 		return -EBUSY;
1436 	if (!kexec_image) {
1437 		error = -EINVAL;
1438 		goto Unlock;
1439 	}
1440 
1441 #ifdef CONFIG_KEXEC_JUMP
1442 	if (kexec_image->preserve_context) {
1443 		mutex_lock(&pm_mutex);
1444 		pm_prepare_console();
1445 		error = freeze_processes();
1446 		if (error) {
1447 			error = -EBUSY;
1448 			goto Restore_console;
1449 		}
1450 		suspend_console();
1451 		error = dpm_suspend_start(PMSG_FREEZE);
1452 		if (error)
1453 			goto Resume_console;
1454 		/* At this point, dpm_suspend_start() has been called,
1455 		 * but *not* dpm_suspend_noirq(). We *must* call
1456 		 * dpm_suspend_noirq() now.  Otherwise, drivers for
1457 		 * some devices (e.g. interrupt controllers) become
1458 		 * desynchronized with the actual state of the
1459 		 * hardware at resume time, and evil weirdness ensues.
1460 		 */
1461 		error = dpm_suspend_noirq(PMSG_FREEZE);
1462 		if (error)
1463 			goto Resume_devices;
1464 		error = disable_nonboot_cpus();
1465 		if (error)
1466 			goto Enable_cpus;
1467 		local_irq_disable();
1468 		/* Suspend system devices */
1469 		error = sysdev_suspend(PMSG_FREEZE);
1470 		if (error)
1471 			goto Enable_irqs;
1472 	} else
1473 #endif
1474 	{
1475 		kernel_restart_prepare(NULL);
1476 		printk(KERN_EMERG "Starting new kernel\n");
1477 		machine_shutdown();
1478 	}
1479 
1480 	machine_kexec(kexec_image);
1481 
1482 #ifdef CONFIG_KEXEC_JUMP
1483 	if (kexec_image->preserve_context) {
1484 		sysdev_resume();
1485  Enable_irqs:
1486 		local_irq_enable();
1487  Enable_cpus:
1488 		enable_nonboot_cpus();
1489 		dpm_resume_noirq(PMSG_RESTORE);
1490  Resume_devices:
1491 		dpm_resume_end(PMSG_RESTORE);
1492  Resume_console:
1493 		resume_console();
1494 		thaw_processes();
1495  Restore_console:
1496 		pm_restore_console();
1497 		mutex_unlock(&pm_mutex);
1498 	}
1499 #endif
1500 
1501  Unlock:
1502 	mutex_unlock(&kexec_mutex);
1503 	return error;
1504 }
1505