2 * kexec.c - kexec system call
3 * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
9 #include <linux/capability.h>
11 #include <linux/file.h>
12 #include <linux/slab.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>
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 #include <linux/syscore_ops.h>
39 #include <asm/uaccess.h>
41 #include <asm/system.h>
42 #include <asm/sections.h>
44 /* Per cpu memory for storing cpu states in case of system crash. */
45 note_buf_t __percpu
*crash_notes
;
47 /* vmcoreinfo stuff */
48 static unsigned char vmcoreinfo_data
[VMCOREINFO_BYTES
];
49 u32 vmcoreinfo_note
[VMCOREINFO_NOTE_SIZE
/4];
50 size_t vmcoreinfo_size
;
51 size_t vmcoreinfo_max_size
= sizeof(vmcoreinfo_data
);
53 /* Location of the reserved area for the crash kernel */
54 struct resource crashk_res
= {
55 .name
= "Crash kernel",
58 .flags
= IORESOURCE_BUSY
| IORESOURCE_MEM
61 int kexec_should_crash(struct task_struct
*p
)
63 if (in_interrupt() || !p
->pid
|| is_global_init(p
) || panic_on_oops
)
69 * When kexec transitions to the new kernel there is a one-to-one
70 * mapping between physical and virtual addresses. On processors
71 * where you can disable the MMU this is trivial, and easy. For
72 * others it is still a simple predictable page table to setup.
74 * In that environment kexec copies the new kernel to its final
75 * resting place. This means I can only support memory whose
76 * physical address can fit in an unsigned long. In particular
77 * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
78 * If the assembly stub has more restrictive requirements
79 * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
80 * defined more restrictively in <asm/kexec.h>.
82 * The code for the transition from the current kernel to the
83 * the new kernel is placed in the control_code_buffer, whose size
84 * is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single
85 * page of memory is necessary, but some architectures require more.
86 * Because this memory must be identity mapped in the transition from
87 * virtual to physical addresses it must live in the range
88 * 0 - TASK_SIZE, as only the user space mappings are arbitrarily
91 * The assembly stub in the control code buffer is passed a linked list
92 * of descriptor pages detailing the source pages of the new kernel,
93 * and the destination addresses of those source pages. As this data
94 * structure is not used in the context of the current OS, it must
97 * The code has been made to work with highmem pages and will use a
98 * destination page in its final resting place (if it happens
99 * to allocate it). The end product of this is that most of the
100 * physical address space, and most of RAM can be used.
102 * Future directions include:
103 * - allocating a page table with the control code buffer identity
104 * mapped, to simplify machine_kexec and make kexec_on_panic more
109 * KIMAGE_NO_DEST is an impossible destination address..., for
110 * allocating pages whose destination address we do not care about.
112 #define KIMAGE_NO_DEST (-1UL)
114 static int kimage_is_destination_range(struct kimage
*image
,
115 unsigned long start
, unsigned long end
);
116 static struct page
*kimage_alloc_page(struct kimage
*image
,
120 static int do_kimage_alloc(struct kimage
**rimage
, unsigned long entry
,
121 unsigned long nr_segments
,
122 struct kexec_segment __user
*segments
)
124 size_t segment_bytes
;
125 struct kimage
*image
;
129 /* Allocate a controlling structure */
131 image
= kzalloc(sizeof(*image
), GFP_KERNEL
);
136 image
->entry
= &image
->head
;
137 image
->last_entry
= &image
->head
;
138 image
->control_page
= ~0; /* By default this does not apply */
139 image
->start
= entry
;
140 image
->type
= KEXEC_TYPE_DEFAULT
;
142 /* Initialize the list of control pages */
143 INIT_LIST_HEAD(&image
->control_pages
);
145 /* Initialize the list of destination pages */
146 INIT_LIST_HEAD(&image
->dest_pages
);
148 /* Initialize the list of unusable pages */
149 INIT_LIST_HEAD(&image
->unuseable_pages
);
151 /* Read in the segments */
152 image
->nr_segments
= nr_segments
;
153 segment_bytes
= nr_segments
* sizeof(*segments
);
154 result
= copy_from_user(image
->segment
, segments
, segment_bytes
);
161 * Verify we have good destination addresses. The caller is
162 * responsible for making certain we don't attempt to load
163 * the new image into invalid or reserved areas of RAM. This
164 * just verifies it is an address we can use.
166 * Since the kernel does everything in page size chunks ensure
167 * the destination addresses are page aligned. Too many
168 * special cases crop of when we don't do this. The most
169 * insidious is getting overlapping destination addresses
170 * simply because addresses are changed to page size
173 result
= -EADDRNOTAVAIL
;
174 for (i
= 0; i
< nr_segments
; i
++) {
175 unsigned long mstart
, mend
;
177 mstart
= image
->segment
[i
].mem
;
178 mend
= mstart
+ image
->segment
[i
].memsz
;
179 if ((mstart
& ~PAGE_MASK
) || (mend
& ~PAGE_MASK
))
181 if (mend
>= KEXEC_DESTINATION_MEMORY_LIMIT
)
185 /* Verify our destination addresses do not overlap.
186 * If we alloed overlapping destination addresses
187 * through very weird things can happen with no
188 * easy explanation as one segment stops on another.
191 for (i
= 0; i
< nr_segments
; i
++) {
192 unsigned long mstart
, mend
;
195 mstart
= image
->segment
[i
].mem
;
196 mend
= mstart
+ image
->segment
[i
].memsz
;
197 for (j
= 0; j
< i
; j
++) {
198 unsigned long pstart
, pend
;
199 pstart
= image
->segment
[j
].mem
;
200 pend
= pstart
+ image
->segment
[j
].memsz
;
201 /* Do the segments overlap ? */
202 if ((mend
> pstart
) && (mstart
< pend
))
207 /* Ensure our buffer sizes are strictly less than
208 * our memory sizes. This should always be the case,
209 * and it is easier to check up front than to be surprised
213 for (i
= 0; i
< nr_segments
; i
++) {
214 if (image
->segment
[i
].bufsz
> image
->segment
[i
].memsz
)
229 static int kimage_normal_alloc(struct kimage
**rimage
, unsigned long entry
,
230 unsigned long nr_segments
,
231 struct kexec_segment __user
*segments
)
234 struct kimage
*image
;
236 /* Allocate and initialize a controlling structure */
238 result
= do_kimage_alloc(&image
, entry
, nr_segments
, segments
);
245 * Find a location for the control code buffer, and add it
246 * the vector of segments so that it's pages will also be
247 * counted as destination pages.
250 image
->control_code_page
= kimage_alloc_control_pages(image
,
251 get_order(KEXEC_CONTROL_PAGE_SIZE
));
252 if (!image
->control_code_page
) {
253 printk(KERN_ERR
"Could not allocate control_code_buffer\n");
257 image
->swap_page
= kimage_alloc_control_pages(image
, 0);
258 if (!image
->swap_page
) {
259 printk(KERN_ERR
"Could not allocate swap buffer\n");
273 static int kimage_crash_alloc(struct kimage
**rimage
, unsigned long entry
,
274 unsigned long nr_segments
,
275 struct kexec_segment __user
*segments
)
278 struct kimage
*image
;
282 /* Verify we have a valid entry point */
283 if ((entry
< crashk_res
.start
) || (entry
> crashk_res
.end
)) {
284 result
= -EADDRNOTAVAIL
;
288 /* Allocate and initialize a controlling structure */
289 result
= do_kimage_alloc(&image
, entry
, nr_segments
, segments
);
293 /* Enable the special crash kernel control page
296 image
->control_page
= crashk_res
.start
;
297 image
->type
= KEXEC_TYPE_CRASH
;
300 * Verify we have good destination addresses. Normally
301 * the caller is responsible for making certain we don't
302 * attempt to load the new image into invalid or reserved
303 * areas of RAM. But crash kernels are preloaded into a
304 * reserved area of ram. We must ensure the addresses
305 * are in the reserved area otherwise preloading the
306 * kernel could corrupt things.
308 result
= -EADDRNOTAVAIL
;
309 for (i
= 0; i
< nr_segments
; i
++) {
310 unsigned long mstart
, mend
;
312 mstart
= image
->segment
[i
].mem
;
313 mend
= mstart
+ image
->segment
[i
].memsz
- 1;
314 /* Ensure we are within the crash kernel limits */
315 if ((mstart
< crashk_res
.start
) || (mend
> crashk_res
.end
))
320 * Find a location for the control code buffer, and add
321 * the vector of segments so that it's pages will also be
322 * counted as destination pages.
325 image
->control_code_page
= kimage_alloc_control_pages(image
,
326 get_order(KEXEC_CONTROL_PAGE_SIZE
));
327 if (!image
->control_code_page
) {
328 printk(KERN_ERR
"Could not allocate control_code_buffer\n");
342 static int kimage_is_destination_range(struct kimage
*image
,
348 for (i
= 0; i
< image
->nr_segments
; i
++) {
349 unsigned long mstart
, mend
;
351 mstart
= image
->segment
[i
].mem
;
352 mend
= mstart
+ image
->segment
[i
].memsz
;
353 if ((end
> mstart
) && (start
< mend
))
360 static struct page
*kimage_alloc_pages(gfp_t gfp_mask
, unsigned int order
)
364 pages
= alloc_pages(gfp_mask
, order
);
366 unsigned int count
, i
;
367 pages
->mapping
= NULL
;
368 set_page_private(pages
, order
);
370 for (i
= 0; i
< count
; i
++)
371 SetPageReserved(pages
+ i
);
377 static void kimage_free_pages(struct page
*page
)
379 unsigned int order
, count
, i
;
381 order
= page_private(page
);
383 for (i
= 0; i
< count
; i
++)
384 ClearPageReserved(page
+ i
);
385 __free_pages(page
, order
);
388 static void kimage_free_page_list(struct list_head
*list
)
390 struct list_head
*pos
, *next
;
392 list_for_each_safe(pos
, next
, list
) {
395 page
= list_entry(pos
, struct page
, lru
);
396 list_del(&page
->lru
);
397 kimage_free_pages(page
);
401 static struct page
*kimage_alloc_normal_control_pages(struct kimage
*image
,
404 /* Control pages are special, they are the intermediaries
405 * that are needed while we copy the rest of the pages
406 * to their final resting place. As such they must
407 * not conflict with either the destination addresses
408 * or memory the kernel is already using.
410 * The only case where we really need more than one of
411 * these are for architectures where we cannot disable
412 * the MMU and must instead generate an identity mapped
413 * page table for all of the memory.
415 * At worst this runs in O(N) of the image size.
417 struct list_head extra_pages
;
422 INIT_LIST_HEAD(&extra_pages
);
424 /* Loop while I can allocate a page and the page allocated
425 * is a destination page.
428 unsigned long pfn
, epfn
, addr
, eaddr
;
430 pages
= kimage_alloc_pages(GFP_KERNEL
, order
);
433 pfn
= page_to_pfn(pages
);
435 addr
= pfn
<< PAGE_SHIFT
;
436 eaddr
= epfn
<< PAGE_SHIFT
;
437 if ((epfn
>= (KEXEC_CONTROL_MEMORY_LIMIT
>> PAGE_SHIFT
)) ||
438 kimage_is_destination_range(image
, addr
, eaddr
)) {
439 list_add(&pages
->lru
, &extra_pages
);
445 /* Remember the allocated page... */
446 list_add(&pages
->lru
, &image
->control_pages
);
448 /* Because the page is already in it's destination
449 * location we will never allocate another page at
450 * that address. Therefore kimage_alloc_pages
451 * will not return it (again) and we don't need
452 * to give it an entry in image->segment[].
455 /* Deal with the destination pages I have inadvertently allocated.
457 * Ideally I would convert multi-page allocations into single
458 * page allocations, and add everything to image->dest_pages.
460 * For now it is simpler to just free the pages.
462 kimage_free_page_list(&extra_pages
);
467 static struct page
*kimage_alloc_crash_control_pages(struct kimage
*image
,
470 /* Control pages are special, they are the intermediaries
471 * that are needed while we copy the rest of the pages
472 * to their final resting place. As such they must
473 * not conflict with either the destination addresses
474 * or memory the kernel is already using.
476 * Control pages are also the only pags we must allocate
477 * when loading a crash kernel. All of the other pages
478 * are specified by the segments and we just memcpy
479 * into them directly.
481 * The only case where we really need more than one of
482 * these are for architectures where we cannot disable
483 * the MMU and must instead generate an identity mapped
484 * page table for all of the memory.
486 * Given the low demand this implements a very simple
487 * allocator that finds the first hole of the appropriate
488 * size in the reserved memory region, and allocates all
489 * of the memory up to and including the hole.
491 unsigned long hole_start
, hole_end
, size
;
495 size
= (1 << order
) << PAGE_SHIFT
;
496 hole_start
= (image
->control_page
+ (size
- 1)) & ~(size
- 1);
497 hole_end
= hole_start
+ size
- 1;
498 while (hole_end
<= crashk_res
.end
) {
501 if (hole_end
> KEXEC_CRASH_CONTROL_MEMORY_LIMIT
)
503 if (hole_end
> crashk_res
.end
)
505 /* See if I overlap any of the segments */
506 for (i
= 0; i
< image
->nr_segments
; i
++) {
507 unsigned long mstart
, mend
;
509 mstart
= image
->segment
[i
].mem
;
510 mend
= mstart
+ image
->segment
[i
].memsz
- 1;
511 if ((hole_end
>= mstart
) && (hole_start
<= mend
)) {
512 /* Advance the hole to the end of the segment */
513 hole_start
= (mend
+ (size
- 1)) & ~(size
- 1);
514 hole_end
= hole_start
+ size
- 1;
518 /* If I don't overlap any segments I have found my hole! */
519 if (i
== image
->nr_segments
) {
520 pages
= pfn_to_page(hole_start
>> PAGE_SHIFT
);
525 image
->control_page
= hole_end
;
531 struct page
*kimage_alloc_control_pages(struct kimage
*image
,
534 struct page
*pages
= NULL
;
536 switch (image
->type
) {
537 case KEXEC_TYPE_DEFAULT
:
538 pages
= kimage_alloc_normal_control_pages(image
, order
);
540 case KEXEC_TYPE_CRASH
:
541 pages
= kimage_alloc_crash_control_pages(image
, order
);
548 static int kimage_add_entry(struct kimage
*image
, kimage_entry_t entry
)
550 if (*image
->entry
!= 0)
553 if (image
->entry
== image
->last_entry
) {
554 kimage_entry_t
*ind_page
;
557 page
= kimage_alloc_page(image
, GFP_KERNEL
, KIMAGE_NO_DEST
);
561 ind_page
= page_address(page
);
562 *image
->entry
= virt_to_phys(ind_page
) | IND_INDIRECTION
;
563 image
->entry
= ind_page
;
564 image
->last_entry
= ind_page
+
565 ((PAGE_SIZE
/sizeof(kimage_entry_t
)) - 1);
567 *image
->entry
= entry
;
574 static int kimage_set_destination(struct kimage
*image
,
575 unsigned long destination
)
579 destination
&= PAGE_MASK
;
580 result
= kimage_add_entry(image
, destination
| IND_DESTINATION
);
582 image
->destination
= destination
;
588 static int kimage_add_page(struct kimage
*image
, unsigned long page
)
593 result
= kimage_add_entry(image
, page
| IND_SOURCE
);
595 image
->destination
+= PAGE_SIZE
;
601 static void kimage_free_extra_pages(struct kimage
*image
)
603 /* Walk through and free any extra destination pages I may have */
604 kimage_free_page_list(&image
->dest_pages
);
606 /* Walk through and free any unusable pages I have cached */
607 kimage_free_page_list(&image
->unuseable_pages
);
610 static void kimage_terminate(struct kimage
*image
)
612 if (*image
->entry
!= 0)
615 *image
->entry
= IND_DONE
;
618 #define for_each_kimage_entry(image, ptr, entry) \
619 for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
620 ptr = (entry & IND_INDIRECTION)? \
621 phys_to_virt((entry & PAGE_MASK)): ptr +1)
623 static void kimage_free_entry(kimage_entry_t entry
)
627 page
= pfn_to_page(entry
>> PAGE_SHIFT
);
628 kimage_free_pages(page
);
631 static void kimage_free(struct kimage
*image
)
633 kimage_entry_t
*ptr
, entry
;
634 kimage_entry_t ind
= 0;
639 kimage_free_extra_pages(image
);
640 for_each_kimage_entry(image
, ptr
, entry
) {
641 if (entry
& IND_INDIRECTION
) {
642 /* Free the previous indirection page */
643 if (ind
& IND_INDIRECTION
)
644 kimage_free_entry(ind
);
645 /* Save this indirection page until we are
650 else if (entry
& IND_SOURCE
)
651 kimage_free_entry(entry
);
653 /* Free the final indirection page */
654 if (ind
& IND_INDIRECTION
)
655 kimage_free_entry(ind
);
657 /* Handle any machine specific cleanup */
658 machine_kexec_cleanup(image
);
660 /* Free the kexec control pages... */
661 kimage_free_page_list(&image
->control_pages
);
665 static kimage_entry_t
*kimage_dst_used(struct kimage
*image
,
668 kimage_entry_t
*ptr
, entry
;
669 unsigned long destination
= 0;
671 for_each_kimage_entry(image
, ptr
, entry
) {
672 if (entry
& IND_DESTINATION
)
673 destination
= entry
& PAGE_MASK
;
674 else if (entry
& IND_SOURCE
) {
675 if (page
== destination
)
677 destination
+= PAGE_SIZE
;
684 static struct page
*kimage_alloc_page(struct kimage
*image
,
686 unsigned long destination
)
689 * Here we implement safeguards to ensure that a source page
690 * is not copied to its destination page before the data on
691 * the destination page is no longer useful.
693 * To do this we maintain the invariant that a source page is
694 * either its own destination page, or it is not a
695 * destination page at all.
697 * That is slightly stronger than required, but the proof
698 * that no problems will not occur is trivial, and the
699 * implementation is simply to verify.
701 * When allocating all pages normally this algorithm will run
702 * in O(N) time, but in the worst case it will run in O(N^2)
703 * time. If the runtime is a problem the data structures can
710 * Walk through the list of destination pages, and see if I
713 list_for_each_entry(page
, &image
->dest_pages
, lru
) {
714 addr
= page_to_pfn(page
) << PAGE_SHIFT
;
715 if (addr
== destination
) {
716 list_del(&page
->lru
);
724 /* Allocate a page, if we run out of memory give up */
725 page
= kimage_alloc_pages(gfp_mask
, 0);
728 /* If the page cannot be used file it away */
729 if (page_to_pfn(page
) >
730 (KEXEC_SOURCE_MEMORY_LIMIT
>> PAGE_SHIFT
)) {
731 list_add(&page
->lru
, &image
->unuseable_pages
);
734 addr
= page_to_pfn(page
) << PAGE_SHIFT
;
736 /* If it is the destination page we want use it */
737 if (addr
== destination
)
740 /* If the page is not a destination page use it */
741 if (!kimage_is_destination_range(image
, addr
,
746 * I know that the page is someones destination page.
747 * See if there is already a source page for this
748 * destination page. And if so swap the source pages.
750 old
= kimage_dst_used(image
, addr
);
753 unsigned long old_addr
;
754 struct page
*old_page
;
756 old_addr
= *old
& PAGE_MASK
;
757 old_page
= pfn_to_page(old_addr
>> PAGE_SHIFT
);
758 copy_highpage(page
, old_page
);
759 *old
= addr
| (*old
& ~PAGE_MASK
);
761 /* The old page I have found cannot be a
762 * destination page, so return it if it's
763 * gfp_flags honor the ones passed in.
765 if (!(gfp_mask
& __GFP_HIGHMEM
) &&
766 PageHighMem(old_page
)) {
767 kimage_free_pages(old_page
);
775 /* Place the page on the destination list I
778 list_add(&page
->lru
, &image
->dest_pages
);
785 static int kimage_load_normal_segment(struct kimage
*image
,
786 struct kexec_segment
*segment
)
789 unsigned long ubytes
, mbytes
;
791 unsigned char __user
*buf
;
795 ubytes
= segment
->bufsz
;
796 mbytes
= segment
->memsz
;
797 maddr
= segment
->mem
;
799 result
= kimage_set_destination(image
, maddr
);
806 size_t uchunk
, mchunk
;
808 page
= kimage_alloc_page(image
, GFP_HIGHUSER
, maddr
);
813 result
= kimage_add_page(image
, page_to_pfn(page
)
819 /* Start with a clear page */
821 ptr
+= maddr
& ~PAGE_MASK
;
822 mchunk
= PAGE_SIZE
- (maddr
& ~PAGE_MASK
);
830 result
= copy_from_user(ptr
, buf
, uchunk
);
845 static int kimage_load_crash_segment(struct kimage
*image
,
846 struct kexec_segment
*segment
)
848 /* For crash dumps kernels we simply copy the data from
849 * user space to it's destination.
850 * We do things a page at a time for the sake of kmap.
853 unsigned long ubytes
, mbytes
;
855 unsigned char __user
*buf
;
859 ubytes
= segment
->bufsz
;
860 mbytes
= segment
->memsz
;
861 maddr
= segment
->mem
;
865 size_t uchunk
, mchunk
;
867 page
= pfn_to_page(maddr
>> PAGE_SHIFT
);
873 ptr
+= maddr
& ~PAGE_MASK
;
874 mchunk
= PAGE_SIZE
- (maddr
& ~PAGE_MASK
);
879 if (uchunk
> ubytes
) {
881 /* Zero the trailing part of the page */
882 memset(ptr
+ uchunk
, 0, mchunk
- uchunk
);
884 result
= copy_from_user(ptr
, buf
, uchunk
);
885 kexec_flush_icache_page(page
);
900 static int kimage_load_segment(struct kimage
*image
,
901 struct kexec_segment
*segment
)
903 int result
= -ENOMEM
;
905 switch (image
->type
) {
906 case KEXEC_TYPE_DEFAULT
:
907 result
= kimage_load_normal_segment(image
, segment
);
909 case KEXEC_TYPE_CRASH
:
910 result
= kimage_load_crash_segment(image
, segment
);
918 * Exec Kernel system call: for obvious reasons only root may call it.
920 * This call breaks up into three pieces.
921 * - A generic part which loads the new kernel from the current
922 * address space, and very carefully places the data in the
925 * - A generic part that interacts with the kernel and tells all of
926 * the devices to shut down. Preventing on-going dmas, and placing
927 * the devices in a consistent state so a later kernel can
930 * - A machine specific part that includes the syscall number
931 * and the copies the image to it's final destination. And
932 * jumps into the image at entry.
934 * kexec does not sync, or unmount filesystems so if you need
935 * that to happen you need to do that yourself.
937 struct kimage
*kexec_image
;
938 struct kimage
*kexec_crash_image
;
940 static DEFINE_MUTEX(kexec_mutex
);
942 SYSCALL_DEFINE4(kexec_load
, unsigned long, entry
, unsigned long, nr_segments
,
943 struct kexec_segment __user
*, segments
, unsigned long, flags
)
945 struct kimage
**dest_image
, *image
;
948 /* We only trust the superuser with rebooting the system. */
949 if (!capable(CAP_SYS_BOOT
))
953 * Verify we have a legal set of flags
954 * This leaves us room for future extensions.
956 if ((flags
& KEXEC_FLAGS
) != (flags
& ~KEXEC_ARCH_MASK
))
959 /* Verify we are on the appropriate architecture */
960 if (((flags
& KEXEC_ARCH_MASK
) != KEXEC_ARCH
) &&
961 ((flags
& KEXEC_ARCH_MASK
) != KEXEC_ARCH_DEFAULT
))
964 /* Put an artificial cap on the number
965 * of segments passed to kexec_load.
967 if (nr_segments
> KEXEC_SEGMENT_MAX
)
973 /* Because we write directly to the reserved memory
974 * region when loading crash kernels we need a mutex here to
975 * prevent multiple crash kernels from attempting to load
976 * simultaneously, and to prevent a crash kernel from loading
977 * over the top of a in use crash kernel.
979 * KISS: always take the mutex.
981 if (!mutex_trylock(&kexec_mutex
))
984 dest_image
= &kexec_image
;
985 if (flags
& KEXEC_ON_CRASH
)
986 dest_image
= &kexec_crash_image
;
987 if (nr_segments
> 0) {
990 /* Loading another kernel to reboot into */
991 if ((flags
& KEXEC_ON_CRASH
) == 0)
992 result
= kimage_normal_alloc(&image
, entry
,
993 nr_segments
, segments
);
994 /* Loading another kernel to switch to if this one crashes */
995 else if (flags
& KEXEC_ON_CRASH
) {
996 /* Free any current crash dump kernel before
999 kimage_free(xchg(&kexec_crash_image
, NULL
));
1000 result
= kimage_crash_alloc(&image
, entry
,
1001 nr_segments
, segments
);
1006 if (flags
& KEXEC_PRESERVE_CONTEXT
)
1007 image
->preserve_context
= 1;
1008 result
= machine_kexec_prepare(image
);
1012 for (i
= 0; i
< nr_segments
; i
++) {
1013 result
= kimage_load_segment(image
, &image
->segment
[i
]);
1017 kimage_terminate(image
);
1019 /* Install the new kernel, and Uninstall the old */
1020 image
= xchg(dest_image
, image
);
1023 mutex_unlock(&kexec_mutex
);
1029 #ifdef CONFIG_COMPAT
1030 asmlinkage
long compat_sys_kexec_load(unsigned long entry
,
1031 unsigned long nr_segments
,
1032 struct compat_kexec_segment __user
*segments
,
1033 unsigned long flags
)
1035 struct compat_kexec_segment in
;
1036 struct kexec_segment out
, __user
*ksegments
;
1037 unsigned long i
, result
;
1039 /* Don't allow clients that don't understand the native
1040 * architecture to do anything.
1042 if ((flags
& KEXEC_ARCH_MASK
) == KEXEC_ARCH_DEFAULT
)
1045 if (nr_segments
> KEXEC_SEGMENT_MAX
)
1048 ksegments
= compat_alloc_user_space(nr_segments
* sizeof(out
));
1049 for (i
=0; i
< nr_segments
; i
++) {
1050 result
= copy_from_user(&in
, &segments
[i
], sizeof(in
));
1054 out
.buf
= compat_ptr(in
.buf
);
1055 out
.bufsz
= in
.bufsz
;
1057 out
.memsz
= in
.memsz
;
1059 result
= copy_to_user(&ksegments
[i
], &out
, sizeof(out
));
1064 return sys_kexec_load(entry
, nr_segments
, ksegments
, flags
);
1068 void crash_kexec(struct pt_regs
*regs
)
1070 /* Take the kexec_mutex here to prevent sys_kexec_load
1071 * running on one cpu from replacing the crash kernel
1072 * we are using after a panic on a different cpu.
1074 * If the crash kernel was not located in a fixed area
1075 * of memory the xchg(&kexec_crash_image) would be
1076 * sufficient. But since I reuse the memory...
1078 if (mutex_trylock(&kexec_mutex
)) {
1079 if (kexec_crash_image
) {
1080 struct pt_regs fixed_regs
;
1082 kmsg_dump(KMSG_DUMP_KEXEC
);
1084 crash_setup_regs(&fixed_regs
, regs
);
1085 crash_save_vmcoreinfo();
1086 machine_crash_shutdown(&fixed_regs
);
1087 machine_kexec(kexec_crash_image
);
1089 mutex_unlock(&kexec_mutex
);
1093 size_t crash_get_memory_size(void)
1096 mutex_lock(&kexec_mutex
);
1097 if (crashk_res
.end
!= crashk_res
.start
)
1098 size
= resource_size(&crashk_res
);
1099 mutex_unlock(&kexec_mutex
);
1103 void __weak
crash_free_reserved_phys_range(unsigned long begin
,
1108 for (addr
= begin
; addr
< end
; addr
+= PAGE_SIZE
) {
1109 ClearPageReserved(pfn_to_page(addr
>> PAGE_SHIFT
));
1110 init_page_count(pfn_to_page(addr
>> PAGE_SHIFT
));
1111 free_page((unsigned long)__va(addr
));
1116 int crash_shrink_memory(unsigned long new_size
)
1119 unsigned long start
, end
;
1121 mutex_lock(&kexec_mutex
);
1123 if (kexec_crash_image
) {
1127 start
= crashk_res
.start
;
1128 end
= crashk_res
.end
;
1130 if (new_size
>= end
- start
+ 1) {
1132 if (new_size
== end
- start
+ 1)
1137 start
= roundup(start
, PAGE_SIZE
);
1138 end
= roundup(start
+ new_size
, PAGE_SIZE
);
1140 crash_free_reserved_phys_range(end
, crashk_res
.end
);
1142 if ((start
== end
) && (crashk_res
.parent
!= NULL
))
1143 release_resource(&crashk_res
);
1144 crashk_res
.end
= end
- 1;
1147 mutex_unlock(&kexec_mutex
);
1151 static u32
*append_elf_note(u32
*buf
, char *name
, unsigned type
, void *data
,
1154 struct elf_note note
;
1156 note
.n_namesz
= strlen(name
) + 1;
1157 note
.n_descsz
= data_len
;
1159 memcpy(buf
, ¬e
, sizeof(note
));
1160 buf
+= (sizeof(note
) + 3)/4;
1161 memcpy(buf
, name
, note
.n_namesz
);
1162 buf
+= (note
.n_namesz
+ 3)/4;
1163 memcpy(buf
, data
, note
.n_descsz
);
1164 buf
+= (note
.n_descsz
+ 3)/4;
1169 static void final_note(u32
*buf
)
1171 struct elf_note note
;
1176 memcpy(buf
, ¬e
, sizeof(note
));
1179 void crash_save_cpu(struct pt_regs
*regs
, int cpu
)
1181 struct elf_prstatus prstatus
;
1184 if ((cpu
< 0) || (cpu
>= nr_cpu_ids
))
1187 /* Using ELF notes here is opportunistic.
1188 * I need a well defined structure format
1189 * for the data I pass, and I need tags
1190 * on the data to indicate what information I have
1191 * squirrelled away. ELF notes happen to provide
1192 * all of that, so there is no need to invent something new.
1194 buf
= (u32
*)per_cpu_ptr(crash_notes
, cpu
);
1197 memset(&prstatus
, 0, sizeof(prstatus
));
1198 prstatus
.pr_pid
= current
->pid
;
1199 elf_core_copy_kernel_regs(&prstatus
.pr_reg
, regs
);
1200 buf
= append_elf_note(buf
, KEXEC_CORE_NOTE_NAME
, NT_PRSTATUS
,
1201 &prstatus
, sizeof(prstatus
));
1205 static int __init
crash_notes_memory_init(void)
1207 /* Allocate memory for saving cpu registers. */
1208 crash_notes
= alloc_percpu(note_buf_t
);
1210 printk("Kexec: Memory allocation for saving cpu register"
1211 " states failed\n");
1216 module_init(crash_notes_memory_init
)
1220 * parsing the "crashkernel" commandline
1222 * this code is intended to be called from architecture specific code
1227 * This function parses command lines in the format
1229 * crashkernel=ramsize-range:size[,...][@offset]
1231 * The function returns 0 on success and -EINVAL on failure.
1233 static int __init
parse_crashkernel_mem(char *cmdline
,
1234 unsigned long long system_ram
,
1235 unsigned long long *crash_size
,
1236 unsigned long long *crash_base
)
1238 char *cur
= cmdline
, *tmp
;
1240 /* for each entry of the comma-separated list */
1242 unsigned long long start
, end
= ULLONG_MAX
, size
;
1244 /* get the start of the range */
1245 start
= memparse(cur
, &tmp
);
1247 pr_warning("crashkernel: Memory value expected\n");
1252 pr_warning("crashkernel: '-' expected\n");
1257 /* if no ':' is here, than we read the end */
1259 end
= memparse(cur
, &tmp
);
1261 pr_warning("crashkernel: Memory "
1262 "value expected\n");
1267 pr_warning("crashkernel: end <= start\n");
1273 pr_warning("crashkernel: ':' expected\n");
1278 size
= memparse(cur
, &tmp
);
1280 pr_warning("Memory value expected\n");
1284 if (size
>= system_ram
) {
1285 pr_warning("crashkernel: invalid size\n");
1290 if (system_ram
>= start
&& system_ram
< end
) {
1294 } while (*cur
++ == ',');
1296 if (*crash_size
> 0) {
1297 while (*cur
&& *cur
!= ' ' && *cur
!= '@')
1301 *crash_base
= memparse(cur
, &tmp
);
1303 pr_warning("Memory value expected "
1314 * That function parses "simple" (old) crashkernel command lines like
1316 * crashkernel=size[@offset]
1318 * It returns 0 on success and -EINVAL on failure.
1320 static int __init
parse_crashkernel_simple(char *cmdline
,
1321 unsigned long long *crash_size
,
1322 unsigned long long *crash_base
)
1324 char *cur
= cmdline
;
1326 *crash_size
= memparse(cmdline
, &cur
);
1327 if (cmdline
== cur
) {
1328 pr_warning("crashkernel: memory value expected\n");
1333 *crash_base
= memparse(cur
+1, &cur
);
1339 * That function is the entry point for command line parsing and should be
1340 * called from the arch-specific code.
1342 int __init
parse_crashkernel(char *cmdline
,
1343 unsigned long long system_ram
,
1344 unsigned long long *crash_size
,
1345 unsigned long long *crash_base
)
1347 char *p
= cmdline
, *ck_cmdline
= NULL
;
1348 char *first_colon
, *first_space
;
1350 BUG_ON(!crash_size
|| !crash_base
);
1354 /* find crashkernel and use the last one if there are more */
1355 p
= strstr(p
, "crashkernel=");
1358 p
= strstr(p
+1, "crashkernel=");
1364 ck_cmdline
+= 12; /* strlen("crashkernel=") */
1367 * if the commandline contains a ':', then that's the extended
1368 * syntax -- if not, it must be the classic syntax
1370 first_colon
= strchr(ck_cmdline
, ':');
1371 first_space
= strchr(ck_cmdline
, ' ');
1372 if (first_colon
&& (!first_space
|| first_colon
< first_space
))
1373 return parse_crashkernel_mem(ck_cmdline
, system_ram
,
1374 crash_size
, crash_base
);
1376 return parse_crashkernel_simple(ck_cmdline
, crash_size
,
1384 void crash_save_vmcoreinfo(void)
1388 if (!vmcoreinfo_size
)
1391 vmcoreinfo_append_str("CRASHTIME=%ld", get_seconds());
1393 buf
= (u32
*)vmcoreinfo_note
;
1395 buf
= append_elf_note(buf
, VMCOREINFO_NOTE_NAME
, 0, vmcoreinfo_data
,
1401 void vmcoreinfo_append_str(const char *fmt
, ...)
1407 va_start(args
, fmt
);
1408 r
= vsnprintf(buf
, sizeof(buf
), fmt
, args
);
1411 if (r
+ vmcoreinfo_size
> vmcoreinfo_max_size
)
1412 r
= vmcoreinfo_max_size
- vmcoreinfo_size
;
1414 memcpy(&vmcoreinfo_data
[vmcoreinfo_size
], buf
, r
);
1416 vmcoreinfo_size
+= r
;
1420 * provide an empty default implementation here -- architecture
1421 * code may override this
1423 void __attribute__ ((weak
)) arch_crash_save_vmcoreinfo(void)
1426 unsigned long __attribute__ ((weak
)) paddr_vmcoreinfo_note(void)
1428 return __pa((unsigned long)(char *)&vmcoreinfo_note
);
1431 static int __init
crash_save_vmcoreinfo_init(void)
1433 VMCOREINFO_OSRELEASE(init_uts_ns
.name
.release
);
1434 VMCOREINFO_PAGESIZE(PAGE_SIZE
);
1436 VMCOREINFO_SYMBOL(init_uts_ns
);
1437 VMCOREINFO_SYMBOL(node_online_map
);
1438 VMCOREINFO_SYMBOL(swapper_pg_dir
);
1439 VMCOREINFO_SYMBOL(_stext
);
1440 VMCOREINFO_SYMBOL(vmlist
);
1442 #ifndef CONFIG_NEED_MULTIPLE_NODES
1443 VMCOREINFO_SYMBOL(mem_map
);
1444 VMCOREINFO_SYMBOL(contig_page_data
);
1446 #ifdef CONFIG_SPARSEMEM
1447 VMCOREINFO_SYMBOL(mem_section
);
1448 VMCOREINFO_LENGTH(mem_section
, NR_SECTION_ROOTS
);
1449 VMCOREINFO_STRUCT_SIZE(mem_section
);
1450 VMCOREINFO_OFFSET(mem_section
, section_mem_map
);
1452 VMCOREINFO_STRUCT_SIZE(page
);
1453 VMCOREINFO_STRUCT_SIZE(pglist_data
);
1454 VMCOREINFO_STRUCT_SIZE(zone
);
1455 VMCOREINFO_STRUCT_SIZE(free_area
);
1456 VMCOREINFO_STRUCT_SIZE(list_head
);
1457 VMCOREINFO_SIZE(nodemask_t
);
1458 VMCOREINFO_OFFSET(page
, flags
);
1459 VMCOREINFO_OFFSET(page
, _count
);
1460 VMCOREINFO_OFFSET(page
, mapping
);
1461 VMCOREINFO_OFFSET(page
, lru
);
1462 VMCOREINFO_OFFSET(pglist_data
, node_zones
);
1463 VMCOREINFO_OFFSET(pglist_data
, nr_zones
);
1464 #ifdef CONFIG_FLAT_NODE_MEM_MAP
1465 VMCOREINFO_OFFSET(pglist_data
, node_mem_map
);
1467 VMCOREINFO_OFFSET(pglist_data
, node_start_pfn
);
1468 VMCOREINFO_OFFSET(pglist_data
, node_spanned_pages
);
1469 VMCOREINFO_OFFSET(pglist_data
, node_id
);
1470 VMCOREINFO_OFFSET(zone
, free_area
);
1471 VMCOREINFO_OFFSET(zone
, vm_stat
);
1472 VMCOREINFO_OFFSET(zone
, spanned_pages
);
1473 VMCOREINFO_OFFSET(free_area
, free_list
);
1474 VMCOREINFO_OFFSET(list_head
, next
);
1475 VMCOREINFO_OFFSET(list_head
, prev
);
1476 VMCOREINFO_OFFSET(vm_struct
, addr
);
1477 VMCOREINFO_LENGTH(zone
.free_area
, MAX_ORDER
);
1478 log_buf_kexec_setup();
1479 VMCOREINFO_LENGTH(free_area
.free_list
, MIGRATE_TYPES
);
1480 VMCOREINFO_NUMBER(NR_FREE_PAGES
);
1481 VMCOREINFO_NUMBER(PG_lru
);
1482 VMCOREINFO_NUMBER(PG_private
);
1483 VMCOREINFO_NUMBER(PG_swapcache
);
1485 arch_crash_save_vmcoreinfo();
1490 module_init(crash_save_vmcoreinfo_init
)
1493 * Move into place and start executing a preloaded standalone
1494 * executable. If nothing was preloaded return an error.
1496 int kernel_kexec(void)
1500 if (!mutex_trylock(&kexec_mutex
))
1507 #ifdef CONFIG_KEXEC_JUMP
1508 if (kexec_image
->preserve_context
) {
1509 mutex_lock(&pm_mutex
);
1510 pm_prepare_console();
1511 error
= freeze_processes();
1514 goto Restore_console
;
1517 error
= dpm_suspend_start(PMSG_FREEZE
);
1519 goto Resume_console
;
1520 /* At this point, dpm_suspend_start() has been called,
1521 * but *not* dpm_suspend_noirq(). We *must* call
1522 * dpm_suspend_noirq() now. Otherwise, drivers for
1523 * some devices (e.g. interrupt controllers) become
1524 * desynchronized with the actual state of the
1525 * hardware at resume time, and evil weirdness ensues.
1527 error
= dpm_suspend_noirq(PMSG_FREEZE
);
1529 goto Resume_devices
;
1530 error
= disable_nonboot_cpus();
1533 local_irq_disable();
1534 error
= syscore_suspend();
1540 kernel_restart_prepare(NULL
);
1541 printk(KERN_EMERG
"Starting new kernel\n");
1545 machine_kexec(kexec_image
);
1547 #ifdef CONFIG_KEXEC_JUMP
1548 if (kexec_image
->preserve_context
) {
1553 enable_nonboot_cpus();
1554 dpm_resume_noirq(PMSG_RESTORE
);
1556 dpm_resume_end(PMSG_RESTORE
);
1561 pm_restore_console();
1562 mutex_unlock(&pm_mutex
);
1567 mutex_unlock(&kexec_mutex
);