Root/kernel/kexec.c

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 <generated/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#include <linux/swap.h>
35#include <linux/kmsg_dump.h>
36
37#include <asm/page.h>
38#include <asm/uaccess.h>
39#include <asm/io.h>
40#include <asm/system.h>
41#include <asm/sections.h>
42
43/* Per cpu memory for storing cpu states in case of system crash. */
44note_buf_t __percpu *crash_notes;
45
46/* vmcoreinfo stuff */
47static unsigned char vmcoreinfo_data[VMCOREINFO_BYTES];
48u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
49size_t vmcoreinfo_size;
50size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
51
52/* Location of the reserved area for the crash kernel */
53struct resource crashk_res = {
54    .name = "Crash kernel",
55    .start = 0,
56    .end = 0,
57    .flags = IORESOURCE_BUSY | IORESOURCE_MEM
58};
59
60int kexec_should_crash(struct task_struct *p)
61{
62    if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
63        return 1;
64    return 0;
65}
66
67/*
68 * When kexec transitions to the new kernel there is a one-to-one
69 * mapping between physical and virtual addresses. On processors
70 * where you can disable the MMU this is trivial, and easy. For
71 * others it is still a simple predictable page table to setup.
72 *
73 * In that environment kexec copies the new kernel to its final
74 * resting place. This means I can only support memory whose
75 * physical address can fit in an unsigned long. In particular
76 * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
77 * If the assembly stub has more restrictive requirements
78 * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
79 * defined more restrictively in <asm/kexec.h>.
80 *
81 * The code for the transition from the current kernel to the
82 * the new kernel is placed in the control_code_buffer, whose size
83 * is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single
84 * page of memory is necessary, but some architectures require more.
85 * Because this memory must be identity mapped in the transition from
86 * virtual to physical addresses it must live in the range
87 * 0 - TASK_SIZE, as only the user space mappings are arbitrarily
88 * modifiable.
89 *
90 * The assembly stub in the control code buffer is passed a linked list
91 * of descriptor pages detailing the source pages of the new kernel,
92 * and the destination addresses of those source pages. As this data
93 * structure is not used in the context of the current OS, it must
94 * be self-contained.
95 *
96 * The code has been made to work with highmem pages and will use a
97 * destination page in its final resting place (if it happens
98 * to allocate it). The end product of this is that most of the
99 * physical address space, and most of RAM can be used.
100 *
101 * Future directions include:
102 * - allocating a page table with the control code buffer identity
103 * mapped, to simplify machine_kexec and make kexec_on_panic more
104 * reliable.
105 */
106
107/*
108 * KIMAGE_NO_DEST is an impossible destination address..., for
109 * allocating pages whose destination address we do not care about.
110 */
111#define KIMAGE_NO_DEST (-1UL)
112
113static int kimage_is_destination_range(struct kimage *image,
114                       unsigned long start, unsigned long end);
115static struct page *kimage_alloc_page(struct kimage *image,
116                       gfp_t gfp_mask,
117                       unsigned long dest);
118
119static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
120                        unsigned long nr_segments,
121                            struct kexec_segment __user *segments)
122{
123    size_t segment_bytes;
124    struct kimage *image;
125    unsigned long i;
126    int result;
127
128    /* Allocate a controlling structure */
129    result = -ENOMEM;
130    image = kzalloc(sizeof(*image), GFP_KERNEL);
131    if (!image)
132        goto out;
133
134    image->head = 0;
135    image->entry = &image->head;
136    image->last_entry = &image->head;
137    image->control_page = ~0; /* By default this does not apply */
138    image->start = entry;
139    image->type = KEXEC_TYPE_DEFAULT;
140
141    /* Initialize the list of control pages */
142    INIT_LIST_HEAD(&image->control_pages);
143
144    /* Initialize the list of destination pages */
145    INIT_LIST_HEAD(&image->dest_pages);
146
147    /* Initialize the list of unuseable pages */
148    INIT_LIST_HEAD(&image->unuseable_pages);
149
150    /* Read in the segments */
151    image->nr_segments = nr_segments;
152    segment_bytes = nr_segments * sizeof(*segments);
153    result = copy_from_user(image->segment, segments, segment_bytes);
154    if (result) {
155        result = -EFAULT;
156        goto out;
157    }
158
159    /*
160     * Verify we have good destination addresses. The caller is
161     * responsible for making certain we don't attempt to load
162     * the new image into invalid or reserved areas of RAM. This
163     * just verifies it is an address we can use.
164     *
165     * Since the kernel does everything in page size chunks ensure
166     * the destination addreses are page aligned. Too many
167     * special cases crop of when we don't do this. The most
168     * insidious is getting overlapping destination addresses
169     * simply because addresses are changed to page size
170     * granularity.
171     */
172    result = -EADDRNOTAVAIL;
173    for (i = 0; i < nr_segments; i++) {
174        unsigned long mstart, mend;
175
176        mstart = image->segment[i].mem;
177        mend = mstart + image->segment[i].memsz;
178        if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
179            goto out;
180        if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
181            goto out;
182    }
183
184    /* Verify our destination addresses do not overlap.
185     * If we alloed overlapping destination addresses
186     * through very weird things can happen with no
187     * easy explanation as one segment stops on another.
188     */
189    result = -EINVAL;
190    for (i = 0; i < nr_segments; i++) {
191        unsigned long mstart, mend;
192        unsigned long j;
193
194        mstart = image->segment[i].mem;
195        mend = mstart + image->segment[i].memsz;
196        for (j = 0; j < i; j++) {
197            unsigned long pstart, pend;
198            pstart = image->segment[j].mem;
199            pend = pstart + image->segment[j].memsz;
200            /* Do the segments overlap ? */
201            if ((mend > pstart) && (mstart < pend))
202                goto out;
203        }
204    }
205
206    /* Ensure our buffer sizes are strictly less than
207     * our memory sizes. This should always be the case,
208     * and it is easier to check up front than to be surprised
209     * later on.
210     */
211    result = -EINVAL;
212    for (i = 0; i < nr_segments; i++) {
213        if (image->segment[i].bufsz > image->segment[i].memsz)
214            goto out;
215    }
216
217    result = 0;
218out:
219    if (result == 0)
220        *rimage = image;
221    else
222        kfree(image);
223
224    return result;
225
226}
227
228static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
229                unsigned long nr_segments,
230                struct kexec_segment __user *segments)
231{
232    int result;
233    struct kimage *image;
234
235    /* Allocate and initialize a controlling structure */
236    image = NULL;
237    result = do_kimage_alloc(&image, entry, nr_segments, segments);
238    if (result)
239        goto out;
240
241    *rimage = image;
242
243    /*
244     * Find a location for the control code buffer, and add it
245     * the vector of segments so that it's pages will also be
246     * counted as destination pages.
247     */
248    result = -ENOMEM;
249    image->control_code_page = kimage_alloc_control_pages(image,
250                       get_order(KEXEC_CONTROL_PAGE_SIZE));
251    if (!image->control_code_page) {
252        printk(KERN_ERR "Could not allocate control_code_buffer\n");
253        goto out;
254    }
255
256    image->swap_page = kimage_alloc_control_pages(image, 0);
257    if (!image->swap_page) {
258        printk(KERN_ERR "Could not allocate swap buffer\n");
259        goto out;
260    }
261
262    result = 0;
263 out:
264    if (result == 0)
265        *rimage = image;
266    else
267        kfree(image);
268
269    return result;
270}
271
272static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
273                unsigned long nr_segments,
274                struct kexec_segment __user *segments)
275{
276    int result;
277    struct kimage *image;
278    unsigned long i;
279
280    image = NULL;
281    /* Verify we have a valid entry point */
282    if ((entry < crashk_res.start) || (entry > crashk_res.end)) {
283        result = -EADDRNOTAVAIL;
284        goto out;
285    }
286
287    /* Allocate and initialize a controlling structure */
288    result = do_kimage_alloc(&image, entry, nr_segments, segments);
289    if (result)
290        goto out;
291
292    /* Enable the special crash kernel control page
293     * allocation policy.
294     */
295    image->control_page = crashk_res.start;
296    image->type = KEXEC_TYPE_CRASH;
297
298    /*
299     * Verify we have good destination addresses. Normally
300     * the caller is responsible for making certain we don't
301     * attempt to load the new image into invalid or reserved
302     * areas of RAM. But crash kernels are preloaded into a
303     * reserved area of ram. We must ensure the addresses
304     * are in the reserved area otherwise preloading the
305     * kernel could corrupt things.
306     */
307    result = -EADDRNOTAVAIL;
308    for (i = 0; i < nr_segments; i++) {
309        unsigned long mstart, mend;
310
311        mstart = image->segment[i].mem;
312        mend = mstart + image->segment[i].memsz - 1;
313        /* Ensure we are within the crash kernel limits */
314        if ((mstart < crashk_res.start) || (mend > crashk_res.end))
315            goto out;
316    }
317
318    /*
319     * Find a location for the control code buffer, and add
320     * the vector of segments so that it's pages will also be
321     * counted as destination pages.
322     */
323    result = -ENOMEM;
324    image->control_code_page = kimage_alloc_control_pages(image,
325                       get_order(KEXEC_CONTROL_PAGE_SIZE));
326    if (!image->control_code_page) {
327        printk(KERN_ERR "Could not allocate control_code_buffer\n");
328        goto out;
329    }
330
331    result = 0;
332out:
333    if (result == 0)
334        *rimage = image;
335    else
336        kfree(image);
337
338    return result;
339}
340
341static int kimage_is_destination_range(struct kimage *image,
342                    unsigned long start,
343                    unsigned long end)
344{
345    unsigned long i;
346
347    for (i = 0; i < image->nr_segments; i++) {
348        unsigned long mstart, mend;
349
350        mstart = image->segment[i].mem;
351        mend = mstart + image->segment[i].memsz;
352        if ((end > mstart) && (start < mend))
353            return 1;
354    }
355
356    return 0;
357}
358
359static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
360{
361    struct page *pages;
362
363    pages = alloc_pages(gfp_mask, order);
364    if (pages) {
365        unsigned int count, i;
366        pages->mapping = NULL;
367        set_page_private(pages, order);
368        count = 1 << order;
369        for (i = 0; i < count; i++)
370            SetPageReserved(pages + i);
371    }
372
373    return pages;
374}
375
376static void kimage_free_pages(struct page *page)
377{
378    unsigned int order, count, i;
379
380    order = page_private(page);
381    count = 1 << order;
382    for (i = 0; i < count; i++)
383        ClearPageReserved(page + i);
384    __free_pages(page, order);
385}
386
387static void kimage_free_page_list(struct list_head *list)
388{
389    struct list_head *pos, *next;
390
391    list_for_each_safe(pos, next, list) {
392        struct page *page;
393
394        page = list_entry(pos, struct page, lru);
395        list_del(&page->lru);
396        kimage_free_pages(page);
397    }
398}
399
400static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
401                            unsigned int order)
402{
403    /* Control pages are special, they are the intermediaries
404     * that are needed while we copy the rest of the pages
405     * to their final resting place. As such they must
406     * not conflict with either the destination addresses
407     * or memory the kernel is already using.
408     *
409     * The only case where we really need more than one of
410     * these are for architectures where we cannot disable
411     * the MMU and must instead generate an identity mapped
412     * page table for all of the memory.
413     *
414     * At worst this runs in O(N) of the image size.
415     */
416    struct list_head extra_pages;
417    struct page *pages;
418    unsigned int count;
419
420    count = 1 << order;
421    INIT_LIST_HEAD(&extra_pages);
422
423    /* Loop while I can allocate a page and the page allocated
424     * is a destination page.
425     */
426    do {
427        unsigned long pfn, epfn, addr, eaddr;
428
429        pages = kimage_alloc_pages(GFP_KERNEL, order);
430        if (!pages)
431            break;
432        pfn = page_to_pfn(pages);
433        epfn = pfn + count;
434        addr = pfn << PAGE_SHIFT;
435        eaddr = epfn << PAGE_SHIFT;
436        if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
437                  kimage_is_destination_range(image, addr, eaddr)) {
438            list_add(&pages->lru, &extra_pages);
439            pages = NULL;
440        }
441    } while (!pages);
442
443    if (pages) {
444        /* Remember the allocated page... */
445        list_add(&pages->lru, &image->control_pages);
446
447        /* Because the page is already in it's destination
448         * location we will never allocate another page at
449         * that address. Therefore kimage_alloc_pages
450         * will not return it (again) and we don't need
451         * to give it an entry in image->segment[].
452         */
453    }
454    /* Deal with the destination pages I have inadvertently allocated.
455     *
456     * Ideally I would convert multi-page allocations into single
457     * page allocations, and add everyting to image->dest_pages.
458     *
459     * For now it is simpler to just free the pages.
460     */
461    kimage_free_page_list(&extra_pages);
462
463    return pages;
464}
465
466static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
467                              unsigned int order)
468{
469    /* Control pages are special, they are the intermediaries
470     * that are needed while we copy the rest of the pages
471     * to their final resting place. As such they must
472     * not conflict with either the destination addresses
473     * or memory the kernel is already using.
474     *
475     * Control pages are also the only pags we must allocate
476     * when loading a crash kernel. All of the other pages
477     * are specified by the segments and we just memcpy
478     * into them directly.
479     *
480     * The only case where we really need more than one of
481     * these are for architectures where we cannot disable
482     * the MMU and must instead generate an identity mapped
483     * page table for all of the memory.
484     *
485     * Given the low demand this implements a very simple
486     * allocator that finds the first hole of the appropriate
487     * size in the reserved memory region, and allocates all
488     * of the memory up to and including the hole.
489     */
490    unsigned long hole_start, hole_end, size;
491    struct page *pages;
492
493    pages = NULL;
494    size = (1 << order) << PAGE_SHIFT;
495    hole_start = (image->control_page + (size - 1)) & ~(size - 1);
496    hole_end = hole_start + size - 1;
497    while (hole_end <= crashk_res.end) {
498        unsigned long i;
499
500        if (hole_end > KEXEC_CONTROL_MEMORY_LIMIT)
501            break;
502        if (hole_end > crashk_res.end)
503            break;
504        /* See if I overlap any of the segments */
505        for (i = 0; i < image->nr_segments; i++) {
506            unsigned long mstart, mend;
507
508            mstart = image->segment[i].mem;
509            mend = mstart + image->segment[i].memsz - 1;
510            if ((hole_end >= mstart) && (hole_start <= mend)) {
511                /* Advance the hole to the end of the segment */
512                hole_start = (mend + (size - 1)) & ~(size - 1);
513                hole_end = hole_start + size - 1;
514                break;
515            }
516        }
517        /* If I don't overlap any segments I have found my hole! */
518        if (i == image->nr_segments) {
519            pages = pfn_to_page(hole_start >> PAGE_SHIFT);
520            break;
521        }
522    }
523    if (pages)
524        image->control_page = hole_end;
525
526    return pages;
527}
528
529
530struct page *kimage_alloc_control_pages(struct kimage *image,
531                     unsigned int order)
532{
533    struct page *pages = NULL;
534
535    switch (image->type) {
536    case KEXEC_TYPE_DEFAULT:
537        pages = kimage_alloc_normal_control_pages(image, order);
538        break;
539    case KEXEC_TYPE_CRASH:
540        pages = kimage_alloc_crash_control_pages(image, order);
541        break;
542    }
543
544    return pages;
545}
546
547static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
548{
549    if (*image->entry != 0)
550        image->entry++;
551
552    if (image->entry == image->last_entry) {
553        kimage_entry_t *ind_page;
554        struct page *page;
555
556        page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
557        if (!page)
558            return -ENOMEM;
559
560        ind_page = page_address(page);
561        *image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
562        image->entry = ind_page;
563        image->last_entry = ind_page +
564                      ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
565    }
566    *image->entry = entry;
567    image->entry++;
568    *image->entry = 0;
569
570    return 0;
571}
572
573static int kimage_set_destination(struct kimage *image,
574                   unsigned long destination)
575{
576    int result;
577
578    destination &= PAGE_MASK;
579    result = kimage_add_entry(image, destination | IND_DESTINATION);
580    if (result == 0)
581        image->destination = destination;
582
583    return result;
584}
585
586
587static int kimage_add_page(struct kimage *image, unsigned long page)
588{
589    int result;
590
591    page &= PAGE_MASK;
592    result = kimage_add_entry(image, page | IND_SOURCE);
593    if (result == 0)
594        image->destination += PAGE_SIZE;
595
596    return result;
597}
598
599
600static void kimage_free_extra_pages(struct kimage *image)
601{
602    /* Walk through and free any extra destination pages I may have */
603    kimage_free_page_list(&image->dest_pages);
604
605    /* Walk through and free any unuseable pages I have cached */
606    kimage_free_page_list(&image->unuseable_pages);
607
608}
609static void kimage_terminate(struct kimage *image)
610{
611    if (*image->entry != 0)
612        image->entry++;
613
614    *image->entry = IND_DONE;
615}
616
617#define for_each_kimage_entry(image, ptr, entry) \
618    for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
619        ptr = (entry & IND_INDIRECTION)? \
620            phys_to_virt((entry & PAGE_MASK)): ptr +1)
621
622static void kimage_free_entry(kimage_entry_t entry)
623{
624    struct page *page;
625
626    page = pfn_to_page(entry >> PAGE_SHIFT);
627    kimage_free_pages(page);
628}
629
630static void kimage_free(struct kimage *image)
631{
632    kimage_entry_t *ptr, entry;
633    kimage_entry_t ind = 0;
634
635    if (!image)
636        return;
637
638    kimage_free_extra_pages(image);
639    for_each_kimage_entry(image, ptr, entry) {
640        if (entry & IND_INDIRECTION) {
641            /* Free the previous indirection page */
642            if (ind & IND_INDIRECTION)
643                kimage_free_entry(ind);
644            /* Save this indirection page until we are
645             * done with it.
646             */
647            ind = entry;
648        }
649        else if (entry & IND_SOURCE)
650            kimage_free_entry(entry);
651    }
652    /* Free the final indirection page */
653    if (ind & IND_INDIRECTION)
654        kimage_free_entry(ind);
655
656    /* Handle any machine specific cleanup */
657    machine_kexec_cleanup(image);
658
659    /* Free the kexec control pages... */
660    kimage_free_page_list(&image->control_pages);
661    kfree(image);
662}
663
664static kimage_entry_t *kimage_dst_used(struct kimage *image,
665                    unsigned long page)
666{
667    kimage_entry_t *ptr, entry;
668    unsigned long destination = 0;
669
670    for_each_kimage_entry(image, ptr, entry) {
671        if (entry & IND_DESTINATION)
672            destination = entry & PAGE_MASK;
673        else if (entry & IND_SOURCE) {
674            if (page == destination)
675                return ptr;
676            destination += PAGE_SIZE;
677        }
678    }
679
680    return NULL;
681}
682
683static struct page *kimage_alloc_page(struct kimage *image,
684                    gfp_t gfp_mask,
685                    unsigned long destination)
686{
687    /*
688     * Here we implement safeguards to ensure that a source page
689     * is not copied to its destination page before the data on
690     * the destination page is no longer useful.
691     *
692     * To do this we maintain the invariant that a source page is
693     * either its own destination page, or it is not a
694     * destination page at all.
695     *
696     * That is slightly stronger than required, but the proof
697     * that no problems will not occur is trivial, and the
698     * implementation is simply to verify.
699     *
700     * When allocating all pages normally this algorithm will run
701     * in O(N) time, but in the worst case it will run in O(N^2)
702     * time. If the runtime is a problem the data structures can
703     * be fixed.
704     */
705    struct page *page;
706    unsigned long addr;
707
708    /*
709     * Walk through the list of destination pages, and see if I
710     * have a match.
711     */
712    list_for_each_entry(page, &image->dest_pages, lru) {
713        addr = page_to_pfn(page) << PAGE_SHIFT;
714        if (addr == destination) {
715            list_del(&page->lru);
716            return page;
717        }
718    }
719    page = NULL;
720    while (1) {
721        kimage_entry_t *old;
722
723        /* Allocate a page, if we run out of memory give up */
724        page = kimage_alloc_pages(gfp_mask, 0);
725        if (!page)
726            return NULL;
727        /* If the page cannot be used file it away */
728        if (page_to_pfn(page) >
729                (KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
730            list_add(&page->lru, &image->unuseable_pages);
731            continue;
732        }
733        addr = page_to_pfn(page) << PAGE_SHIFT;
734
735        /* If it is the destination page we want use it */
736        if (addr == destination)
737            break;
738
739        /* If the page is not a destination page use it */
740        if (!kimage_is_destination_range(image, addr,
741                          addr + PAGE_SIZE))
742            break;
743
744        /*
745         * I know that the page is someones destination page.
746         * See if there is already a source page for this
747         * destination page. And if so swap the source pages.
748         */
749        old = kimage_dst_used(image, addr);
750        if (old) {
751            /* If so move it */
752            unsigned long old_addr;
753            struct page *old_page;
754
755            old_addr = *old & PAGE_MASK;
756            old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
757            copy_highpage(page, old_page);
758            *old = addr | (*old & ~PAGE_MASK);
759
760            /* The old page I have found cannot be a
761             * destination page, so return it if it's
762             * gfp_flags honor the ones passed in.
763             */
764            if (!(gfp_mask & __GFP_HIGHMEM) &&
765                PageHighMem(old_page)) {
766                kimage_free_pages(old_page);
767                continue;
768            }
769            addr = old_addr;
770            page = old_page;
771            break;
772        }
773        else {
774            /* Place the page on the destination list I
775             * will use it later.
776             */
777            list_add(&page->lru, &image->dest_pages);
778        }
779    }
780
781    return page;
782}
783
784static int kimage_load_normal_segment(struct kimage *image,
785                     struct kexec_segment *segment)
786{
787    unsigned long maddr;
788    unsigned long ubytes, mbytes;
789    int result;
790    unsigned char __user *buf;
791
792    result = 0;
793    buf = segment->buf;
794    ubytes = segment->bufsz;
795    mbytes = segment->memsz;
796    maddr = segment->mem;
797
798    result = kimage_set_destination(image, maddr);
799    if (result < 0)
800        goto out;
801
802    while (mbytes) {
803        struct page *page;
804        char *ptr;
805        size_t uchunk, mchunk;
806
807        page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
808        if (!page) {
809            result = -ENOMEM;
810            goto out;
811        }
812        result = kimage_add_page(image, page_to_pfn(page)
813                                << PAGE_SHIFT);
814        if (result < 0)
815            goto out;
816
817        ptr = kmap(page);
818        /* Start with a clear page */
819        memset(ptr, 0, PAGE_SIZE);
820        ptr += maddr & ~PAGE_MASK;
821        mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
822        if (mchunk > mbytes)
823            mchunk = mbytes;
824
825        uchunk = mchunk;
826        if (uchunk > ubytes)
827            uchunk = ubytes;
828
829        result = copy_from_user(ptr, buf, uchunk);
830        kunmap(page);
831        if (result) {
832            result = -EFAULT;
833            goto out;
834        }
835        ubytes -= uchunk;
836        maddr += mchunk;
837        buf += mchunk;
838        mbytes -= mchunk;
839    }
840out:
841    return result;
842}
843
844static int kimage_load_crash_segment(struct kimage *image,
845                    struct kexec_segment *segment)
846{
847    /* For crash dumps kernels we simply copy the data from
848     * user space to it's destination.
849     * We do things a page at a time for the sake of kmap.
850     */
851    unsigned long maddr;
852    unsigned long ubytes, mbytes;
853    int result;
854    unsigned char __user *buf;
855
856    result = 0;
857    buf = segment->buf;
858    ubytes = segment->bufsz;
859    mbytes = segment->memsz;
860    maddr = segment->mem;
861    while (mbytes) {
862        struct page *page;
863        char *ptr;
864        size_t uchunk, mchunk;
865
866        page = pfn_to_page(maddr >> PAGE_SHIFT);
867        if (!page) {
868            result = -ENOMEM;
869            goto out;
870        }
871        ptr = kmap(page);
872        ptr += maddr & ~PAGE_MASK;
873        mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
874        if (mchunk > mbytes)
875            mchunk = mbytes;
876
877        uchunk = mchunk;
878        if (uchunk > ubytes) {
879            uchunk = ubytes;
880            /* Zero the trailing part of the page */
881            memset(ptr + uchunk, 0, mchunk - uchunk);
882        }
883        result = copy_from_user(ptr, buf, uchunk);
884        kexec_flush_icache_page(page);
885        kunmap(page);
886        if (result) {
887            result = -EFAULT;
888            goto out;
889        }
890        ubytes -= uchunk;
891        maddr += mchunk;
892        buf += mchunk;
893        mbytes -= mchunk;
894    }
895out:
896    return result;
897}
898
899static int kimage_load_segment(struct kimage *image,
900                struct kexec_segment *segment)
901{
902    int result = -ENOMEM;
903
904    switch (image->type) {
905    case KEXEC_TYPE_DEFAULT:
906        result = kimage_load_normal_segment(image, segment);
907        break;
908    case KEXEC_TYPE_CRASH:
909        result = kimage_load_crash_segment(image, segment);
910        break;
911    }
912
913    return result;
914}
915
916/*
917 * Exec Kernel system call: for obvious reasons only root may call it.
918 *
919 * This call breaks up into three pieces.
920 * - A generic part which loads the new kernel from the current
921 * address space, and very carefully places the data in the
922 * allocated pages.
923 *
924 * - A generic part that interacts with the kernel and tells all of
925 * the devices to shut down. Preventing on-going dmas, and placing
926 * the devices in a consistent state so a later kernel can
927 * reinitialize them.
928 *
929 * - A machine specific part that includes the syscall number
930 * and the copies the image to it's final destination. And
931 * jumps into the image at entry.
932 *
933 * kexec does not sync, or unmount filesystems so if you need
934 * that to happen you need to do that yourself.
935 */
936struct kimage *kexec_image;
937struct kimage *kexec_crash_image;
938
939static DEFINE_MUTEX(kexec_mutex);
940
941SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
942        struct kexec_segment __user *, segments, unsigned long, flags)
943{
944    struct kimage **dest_image, *image;
945    int result;
946
947    /* We only trust the superuser with rebooting the system. */
948    if (!capable(CAP_SYS_BOOT))
949        return -EPERM;
950
951    /*
952     * Verify we have a legal set of flags
953     * This leaves us room for future extensions.
954     */
955    if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
956        return -EINVAL;
957
958    /* Verify we are on the appropriate architecture */
959    if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
960        ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
961        return -EINVAL;
962
963    /* Put an artificial cap on the number
964     * of segments passed to kexec_load.
965     */
966    if (nr_segments > KEXEC_SEGMENT_MAX)
967        return -EINVAL;
968
969    image = NULL;
970    result = 0;
971
972    /* Because we write directly to the reserved memory
973     * region when loading crash kernels we need a mutex here to
974     * prevent multiple crash kernels from attempting to load
975     * simultaneously, and to prevent a crash kernel from loading
976     * over the top of a in use crash kernel.
977     *
978     * KISS: always take the mutex.
979     */
980    if (!mutex_trylock(&kexec_mutex))
981        return -EBUSY;
982
983    dest_image = &kexec_image;
984    if (flags & KEXEC_ON_CRASH)
985        dest_image = &kexec_crash_image;
986    if (nr_segments > 0) {
987        unsigned long i;
988
989        /* Loading another kernel to reboot into */
990        if ((flags & KEXEC_ON_CRASH) == 0)
991            result = kimage_normal_alloc(&image, entry,
992                            nr_segments, segments);
993        /* Loading another kernel to switch to if this one crashes */
994        else if (flags & KEXEC_ON_CRASH) {
995            /* Free any current crash dump kernel before
996             * we corrupt it.
997             */
998            kimage_free(xchg(&kexec_crash_image, NULL));
999            result = kimage_crash_alloc(&image, entry,
1000                             nr_segments, segments);
1001        }
1002        if (result)
1003            goto out;
1004
1005        if (flags & KEXEC_PRESERVE_CONTEXT)
1006            image->preserve_context = 1;
1007        result = machine_kexec_prepare(image);
1008        if (result)
1009            goto out;
1010
1011        for (i = 0; i < nr_segments; i++) {
1012            result = kimage_load_segment(image, &image->segment[i]);
1013            if (result)
1014                goto out;
1015        }
1016        kimage_terminate(image);
1017    }
1018    /* Install the new kernel, and Uninstall the old */
1019    image = xchg(dest_image, image);
1020
1021out:
1022    mutex_unlock(&kexec_mutex);
1023    kimage_free(image);
1024
1025    return result;
1026}
1027
1028#ifdef CONFIG_COMPAT
1029asmlinkage long compat_sys_kexec_load(unsigned long entry,
1030                unsigned long nr_segments,
1031                struct compat_kexec_segment __user *segments,
1032                unsigned long flags)
1033{
1034    struct compat_kexec_segment in;
1035    struct kexec_segment out, __user *ksegments;
1036    unsigned long i, result;
1037
1038    /* Don't allow clients that don't understand the native
1039     * architecture to do anything.
1040     */
1041    if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
1042        return -EINVAL;
1043
1044    if (nr_segments > KEXEC_SEGMENT_MAX)
1045        return -EINVAL;
1046
1047    ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
1048    for (i=0; i < nr_segments; i++) {
1049        result = copy_from_user(&in, &segments[i], sizeof(in));
1050        if (result)
1051            return -EFAULT;
1052
1053        out.buf = compat_ptr(in.buf);
1054        out.bufsz = in.bufsz;
1055        out.mem = in.mem;
1056        out.memsz = in.memsz;
1057
1058        result = copy_to_user(&ksegments[i], &out, sizeof(out));
1059        if (result)
1060            return -EFAULT;
1061    }
1062
1063    return sys_kexec_load(entry, nr_segments, ksegments, flags);
1064}
1065#endif
1066
1067void crash_kexec(struct pt_regs *regs)
1068{
1069    /* Take the kexec_mutex here to prevent sys_kexec_load
1070     * running on one cpu from replacing the crash kernel
1071     * we are using after a panic on a different cpu.
1072     *
1073     * If the crash kernel was not located in a fixed area
1074     * of memory the xchg(&kexec_crash_image) would be
1075     * sufficient. But since I reuse the memory...
1076     */
1077    if (mutex_trylock(&kexec_mutex)) {
1078        if (kexec_crash_image) {
1079            struct pt_regs fixed_regs;
1080
1081            kmsg_dump(KMSG_DUMP_KEXEC);
1082
1083            crash_setup_regs(&fixed_regs, regs);
1084            crash_save_vmcoreinfo();
1085            machine_crash_shutdown(&fixed_regs);
1086            machine_kexec(kexec_crash_image);
1087        }
1088        mutex_unlock(&kexec_mutex);
1089    }
1090}
1091
1092size_t crash_get_memory_size(void)
1093{
1094    size_t size = 0;
1095    mutex_lock(&kexec_mutex);
1096    if (crashk_res.end != crashk_res.start)
1097        size = crashk_res.end - crashk_res.start + 1;
1098    mutex_unlock(&kexec_mutex);
1099    return size;
1100}
1101
1102static void free_reserved_phys_range(unsigned long begin, unsigned long end)
1103{
1104    unsigned long addr;
1105
1106    for (addr = begin; addr < end; addr += PAGE_SIZE) {
1107        ClearPageReserved(pfn_to_page(addr >> PAGE_SHIFT));
1108        init_page_count(pfn_to_page(addr >> PAGE_SHIFT));
1109        free_page((unsigned long)__va(addr));
1110        totalram_pages++;
1111    }
1112}
1113
1114int crash_shrink_memory(unsigned long new_size)
1115{
1116    int ret = 0;
1117    unsigned long start, end;
1118
1119    mutex_lock(&kexec_mutex);
1120
1121    if (kexec_crash_image) {
1122        ret = -ENOENT;
1123        goto unlock;
1124    }
1125    start = crashk_res.start;
1126    end = crashk_res.end;
1127
1128    if (new_size >= end - start + 1) {
1129        ret = -EINVAL;
1130        if (new_size == end - start + 1)
1131            ret = 0;
1132        goto unlock;
1133    }
1134
1135    start = roundup(start, PAGE_SIZE);
1136    end = roundup(start + new_size, PAGE_SIZE);
1137
1138    free_reserved_phys_range(end, crashk_res.end);
1139
1140    if ((start == end) && (crashk_res.parent != NULL))
1141        release_resource(&crashk_res);
1142    crashk_res.end = end - 1;
1143
1144unlock:
1145    mutex_unlock(&kexec_mutex);
1146    return ret;
1147}
1148
1149static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
1150                size_t data_len)
1151{
1152    struct elf_note note;
1153
1154    note.n_namesz = strlen(name) + 1;
1155    note.n_descsz = data_len;
1156    note.n_type = type;
1157    memcpy(buf, &note, sizeof(note));
1158    buf += (sizeof(note) + 3)/4;
1159    memcpy(buf, name, note.n_namesz);
1160    buf += (note.n_namesz + 3)/4;
1161    memcpy(buf, data, note.n_descsz);
1162    buf += (note.n_descsz + 3)/4;
1163
1164    return buf;
1165}
1166
1167static void final_note(u32 *buf)
1168{
1169    struct elf_note note;
1170
1171    note.n_namesz = 0;
1172    note.n_descsz = 0;
1173    note.n_type = 0;
1174    memcpy(buf, &note, sizeof(note));
1175}
1176
1177void crash_save_cpu(struct pt_regs *regs, int cpu)
1178{
1179    struct elf_prstatus prstatus;
1180    u32 *buf;
1181
1182    if ((cpu < 0) || (cpu >= nr_cpu_ids))
1183        return;
1184
1185    /* Using ELF notes here is opportunistic.
1186     * I need a well defined structure format
1187     * for the data I pass, and I need tags
1188     * on the data to indicate what information I have
1189     * squirrelled away. ELF notes happen to provide
1190     * all of that, so there is no need to invent something new.
1191     */
1192    buf = (u32*)per_cpu_ptr(crash_notes, cpu);
1193    if (!buf)
1194        return;
1195    memset(&prstatus, 0, sizeof(prstatus));
1196    prstatus.pr_pid = current->pid;
1197    elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
1198    buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
1199                        &prstatus, sizeof(prstatus));
1200    final_note(buf);
1201}
1202
1203static int __init crash_notes_memory_init(void)
1204{
1205    /* Allocate memory for saving cpu registers. */
1206    crash_notes = alloc_percpu(note_buf_t);
1207    if (!crash_notes) {
1208        printk("Kexec: Memory allocation for saving cpu register"
1209        " states failed\n");
1210        return -ENOMEM;
1211    }
1212    return 0;
1213}
1214module_init(crash_notes_memory_init)
1215
1216
1217/*
1218 * parsing the "crashkernel" commandline
1219 *
1220 * this code is intended to be called from architecture specific code
1221 */
1222
1223
1224/*
1225 * This function parses command lines in the format
1226 *
1227 * crashkernel=ramsize-range:size[,...][@offset]
1228 *
1229 * The function returns 0 on success and -EINVAL on failure.
1230 */
1231static int __init parse_crashkernel_mem(char *cmdline,
1232                    unsigned long long system_ram,
1233                    unsigned long long *crash_size,
1234                    unsigned long long *crash_base)
1235{
1236    char *cur = cmdline, *tmp;
1237
1238    /* for each entry of the comma-separated list */
1239    do {
1240        unsigned long long start, end = ULLONG_MAX, size;
1241
1242        /* get the start of the range */
1243        start = memparse(cur, &tmp);
1244        if (cur == tmp) {
1245            pr_warning("crashkernel: Memory value expected\n");
1246            return -EINVAL;
1247        }
1248        cur = tmp;
1249        if (*cur != '-') {
1250            pr_warning("crashkernel: '-' expected\n");
1251            return -EINVAL;
1252        }
1253        cur++;
1254
1255        /* if no ':' is here, than we read the end */
1256        if (*cur != ':') {
1257            end = memparse(cur, &tmp);
1258            if (cur == tmp) {
1259                pr_warning("crashkernel: Memory "
1260                        "value expected\n");
1261                return -EINVAL;
1262            }
1263            cur = tmp;
1264            if (end <= start) {
1265                pr_warning("crashkernel: end <= start\n");
1266                return -EINVAL;
1267            }
1268        }
1269
1270        if (*cur != ':') {
1271            pr_warning("crashkernel: ':' expected\n");
1272            return -EINVAL;
1273        }
1274        cur++;
1275
1276        size = memparse(cur, &tmp);
1277        if (cur == tmp) {
1278            pr_warning("Memory value expected\n");
1279            return -EINVAL;
1280        }
1281        cur = tmp;
1282        if (size >= system_ram) {
1283            pr_warning("crashkernel: invalid size\n");
1284            return -EINVAL;
1285        }
1286
1287        /* match ? */
1288        if (system_ram >= start && system_ram < end) {
1289            *crash_size = size;
1290            break;
1291        }
1292    } while (*cur++ == ',');
1293
1294    if (*crash_size > 0) {
1295        while (*cur && *cur != ' ' && *cur != '@')
1296            cur++;
1297        if (*cur == '@') {
1298            cur++;
1299            *crash_base = memparse(cur, &tmp);
1300            if (cur == tmp) {
1301                pr_warning("Memory value expected "
1302                        "after '@'\n");
1303                return -EINVAL;
1304            }
1305        }
1306    }
1307
1308    return 0;
1309}
1310
1311/*
1312 * That function parses "simple" (old) crashkernel command lines like
1313 *
1314 * crashkernel=size[@offset]
1315 *
1316 * It returns 0 on success and -EINVAL on failure.
1317 */
1318static int __init parse_crashkernel_simple(char *cmdline,
1319                       unsigned long long *crash_size,
1320                       unsigned long long *crash_base)
1321{
1322    char *cur = cmdline;
1323
1324    *crash_size = memparse(cmdline, &cur);
1325    if (cmdline == cur) {
1326        pr_warning("crashkernel: memory value expected\n");
1327        return -EINVAL;
1328    }
1329
1330    if (*cur == '@')
1331        *crash_base = memparse(cur+1, &cur);
1332
1333    return 0;
1334}
1335
1336/*
1337 * That function is the entry point for command line parsing and should be
1338 * called from the arch-specific code.
1339 */
1340int __init parse_crashkernel(char *cmdline,
1341                 unsigned long long system_ram,
1342                 unsigned long long *crash_size,
1343                 unsigned long long *crash_base)
1344{
1345    char *p = cmdline, *ck_cmdline = NULL;
1346    char *first_colon, *first_space;
1347
1348    BUG_ON(!crash_size || !crash_base);
1349    *crash_size = 0;
1350    *crash_base = 0;
1351
1352    /* find crashkernel and use the last one if there are more */
1353    p = strstr(p, "crashkernel=");
1354    while (p) {
1355        ck_cmdline = p;
1356        p = strstr(p+1, "crashkernel=");
1357    }
1358
1359    if (!ck_cmdline)
1360        return -EINVAL;
1361
1362    ck_cmdline += 12; /* strlen("crashkernel=") */
1363
1364    /*
1365     * if the commandline contains a ':', then that's the extended
1366     * syntax -- if not, it must be the classic syntax
1367     */
1368    first_colon = strchr(ck_cmdline, ':');
1369    first_space = strchr(ck_cmdline, ' ');
1370    if (first_colon && (!first_space || first_colon < first_space))
1371        return parse_crashkernel_mem(ck_cmdline, system_ram,
1372                crash_size, crash_base);
1373    else
1374        return parse_crashkernel_simple(ck_cmdline, crash_size,
1375                crash_base);
1376
1377    return 0;
1378}
1379
1380
1381
1382void crash_save_vmcoreinfo(void)
1383{
1384    u32 *buf;
1385
1386    if (!vmcoreinfo_size)
1387        return;
1388
1389    vmcoreinfo_append_str("CRASHTIME=%ld", get_seconds());
1390
1391    buf = (u32 *)vmcoreinfo_note;
1392
1393    buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
1394                  vmcoreinfo_size);
1395
1396    final_note(buf);
1397}
1398
1399void vmcoreinfo_append_str(const char *fmt, ...)
1400{
1401    va_list args;
1402    char buf[0x50];
1403    int r;
1404
1405    va_start(args, fmt);
1406    r = vsnprintf(buf, sizeof(buf), fmt, args);
1407    va_end(args);
1408
1409    if (r + vmcoreinfo_size > vmcoreinfo_max_size)
1410        r = vmcoreinfo_max_size - vmcoreinfo_size;
1411
1412    memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
1413
1414    vmcoreinfo_size += r;
1415}
1416
1417/*
1418 * provide an empty default implementation here -- architecture
1419 * code may override this
1420 */
1421void __attribute__ ((weak)) arch_crash_save_vmcoreinfo(void)
1422{}
1423
1424unsigned long __attribute__ ((weak)) paddr_vmcoreinfo_note(void)
1425{
1426    return __pa((unsigned long)(char *)&vmcoreinfo_note);
1427}
1428
1429static int __init crash_save_vmcoreinfo_init(void)
1430{
1431    VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
1432    VMCOREINFO_PAGESIZE(PAGE_SIZE);
1433
1434    VMCOREINFO_SYMBOL(init_uts_ns);
1435    VMCOREINFO_SYMBOL(node_online_map);
1436    VMCOREINFO_SYMBOL(swapper_pg_dir);
1437    VMCOREINFO_SYMBOL(_stext);
1438    VMCOREINFO_SYMBOL(vmlist);
1439
1440#ifndef CONFIG_NEED_MULTIPLE_NODES
1441    VMCOREINFO_SYMBOL(mem_map);
1442    VMCOREINFO_SYMBOL(contig_page_data);
1443#endif
1444#ifdef CONFIG_SPARSEMEM
1445    VMCOREINFO_SYMBOL(mem_section);
1446    VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
1447    VMCOREINFO_STRUCT_SIZE(mem_section);
1448    VMCOREINFO_OFFSET(mem_section, section_mem_map);
1449#endif
1450    VMCOREINFO_STRUCT_SIZE(page);
1451    VMCOREINFO_STRUCT_SIZE(pglist_data);
1452    VMCOREINFO_STRUCT_SIZE(zone);
1453    VMCOREINFO_STRUCT_SIZE(free_area);
1454    VMCOREINFO_STRUCT_SIZE(list_head);
1455    VMCOREINFO_SIZE(nodemask_t);
1456    VMCOREINFO_OFFSET(page, flags);
1457    VMCOREINFO_OFFSET(page, _count);
1458    VMCOREINFO_OFFSET(page, mapping);
1459    VMCOREINFO_OFFSET(page, lru);
1460    VMCOREINFO_OFFSET(pglist_data, node_zones);
1461    VMCOREINFO_OFFSET(pglist_data, nr_zones);
1462#ifdef CONFIG_FLAT_NODE_MEM_MAP
1463    VMCOREINFO_OFFSET(pglist_data, node_mem_map);
1464#endif
1465    VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
1466    VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
1467    VMCOREINFO_OFFSET(pglist_data, node_id);
1468    VMCOREINFO_OFFSET(zone, free_area);
1469    VMCOREINFO_OFFSET(zone, vm_stat);
1470    VMCOREINFO_OFFSET(zone, spanned_pages);
1471    VMCOREINFO_OFFSET(free_area, free_list);
1472    VMCOREINFO_OFFSET(list_head, next);
1473    VMCOREINFO_OFFSET(list_head, prev);
1474    VMCOREINFO_OFFSET(vm_struct, addr);
1475    VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
1476    log_buf_kexec_setup();
1477    VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
1478    VMCOREINFO_NUMBER(NR_FREE_PAGES);
1479    VMCOREINFO_NUMBER(PG_lru);
1480    VMCOREINFO_NUMBER(PG_private);
1481    VMCOREINFO_NUMBER(PG_swapcache);
1482
1483    arch_crash_save_vmcoreinfo();
1484
1485    return 0;
1486}
1487
1488module_init(crash_save_vmcoreinfo_init)
1489
1490/*
1491 * Move into place and start executing a preloaded standalone
1492 * executable. If nothing was preloaded return an error.
1493 */
1494int kernel_kexec(void)
1495{
1496    int error = 0;
1497
1498    if (!mutex_trylock(&kexec_mutex))
1499        return -EBUSY;
1500    if (!kexec_image) {
1501        error = -EINVAL;
1502        goto Unlock;
1503    }
1504
1505#ifdef CONFIG_KEXEC_JUMP
1506    if (kexec_image->preserve_context) {
1507        mutex_lock(&pm_mutex);
1508        pm_prepare_console();
1509        error = freeze_processes();
1510        if (error) {
1511            error = -EBUSY;
1512            goto Restore_console;
1513        }
1514        suspend_console();
1515        error = dpm_suspend_start(PMSG_FREEZE);
1516        if (error)
1517            goto Resume_console;
1518        /* At this point, dpm_suspend_start() has been called,
1519         * but *not* dpm_suspend_noirq(). We *must* call
1520         * dpm_suspend_noirq() now. Otherwise, drivers for
1521         * some devices (e.g. interrupt controllers) become
1522         * desynchronized with the actual state of the
1523         * hardware at resume time, and evil weirdness ensues.
1524         */
1525        error = dpm_suspend_noirq(PMSG_FREEZE);
1526        if (error)
1527            goto Resume_devices;
1528        error = disable_nonboot_cpus();
1529        if (error)
1530            goto Enable_cpus;
1531        local_irq_disable();
1532        /* Suspend system devices */
1533        error = sysdev_suspend(PMSG_FREEZE);
1534        if (error)
1535            goto Enable_irqs;
1536    } else
1537#endif
1538    {
1539        kernel_restart_prepare(NULL);
1540        printk(KERN_EMERG "Starting new kernel\n");
1541        machine_shutdown();
1542    }
1543
1544    machine_kexec(kexec_image);
1545
1546#ifdef CONFIG_KEXEC_JUMP
1547    if (kexec_image->preserve_context) {
1548        sysdev_resume();
1549 Enable_irqs:
1550        local_irq_enable();
1551 Enable_cpus:
1552        enable_nonboot_cpus();
1553        dpm_resume_noirq(PMSG_RESTORE);
1554 Resume_devices:
1555        dpm_resume_end(PMSG_RESTORE);
1556 Resume_console:
1557        resume_console();
1558        thaw_processes();
1559 Restore_console:
1560        pm_restore_console();
1561        mutex_unlock(&pm_mutex);
1562    }
1563#endif
1564
1565 Unlock:
1566    mutex_unlock(&kexec_mutex);
1567    return error;
1568}
1569

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