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/spinlock.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>
29 #include <asm/uaccess.h>
31 #include <asm/system.h>
32 #include <asm/sections.h>
34 /* Per cpu memory for storing cpu states in case of system crash. */
35 note_buf_t* crash_notes;
37 /* vmcoreinfo stuff */
38 unsigned char vmcoreinfo_data[VMCOREINFO_BYTES];
39 u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
40 size_t vmcoreinfo_size;
41 size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
43 /* Location of the reserved area for the crash kernel */
44 struct resource crashk_res = {
45 .name = "Crash kernel",
48 .flags = IORESOURCE_BUSY | IORESOURCE_MEM
51 int kexec_should_crash(struct task_struct *p)
53 if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
59 * When kexec transitions to the new kernel there is a one-to-one
60 * mapping between physical and virtual addresses. On processors
61 * where you can disable the MMU this is trivial, and easy. For
62 * others it is still a simple predictable page table to setup.
64 * In that environment kexec copies the new kernel to its final
65 * resting place. This means I can only support memory whose
66 * physical address can fit in an unsigned long. In particular
67 * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
68 * If the assembly stub has more restrictive requirements
69 * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
70 * defined more restrictively in <asm/kexec.h>.
72 * The code for the transition from the current kernel to the
73 * the new kernel is placed in the control_code_buffer, whose size
74 * is given by KEXEC_CONTROL_CODE_SIZE. In the best case only a single
75 * page of memory is necessary, but some architectures require more.
76 * Because this memory must be identity mapped in the transition from
77 * virtual to physical addresses it must live in the range
78 * 0 - TASK_SIZE, as only the user space mappings are arbitrarily
81 * The assembly stub in the control code buffer is passed a linked list
82 * of descriptor pages detailing the source pages of the new kernel,
83 * and the destination addresses of those source pages. As this data
84 * structure is not used in the context of the current OS, it must
87 * The code has been made to work with highmem pages and will use a
88 * destination page in its final resting place (if it happens
89 * to allocate it). The end product of this is that most of the
90 * physical address space, and most of RAM can be used.
92 * Future directions include:
93 * - allocating a page table with the control code buffer identity
94 * mapped, to simplify machine_kexec and make kexec_on_panic more
99 * KIMAGE_NO_DEST is an impossible destination address..., for
100 * allocating pages whose destination address we do not care about.
102 #define KIMAGE_NO_DEST (-1UL)
104 static int kimage_is_destination_range(struct kimage *image,
105 unsigned long start, unsigned long end);
106 static struct page *kimage_alloc_page(struct kimage *image,
110 static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
111 unsigned long nr_segments,
112 struct kexec_segment __user *segments)
114 size_t segment_bytes;
115 struct kimage *image;
119 /* Allocate a controlling structure */
121 image = kzalloc(sizeof(*image), GFP_KERNEL);
126 image->entry = &image->head;
127 image->last_entry = &image->head;
128 image->control_page = ~0; /* By default this does not apply */
129 image->start = entry;
130 image->type = KEXEC_TYPE_DEFAULT;
132 /* Initialize the list of control pages */
133 INIT_LIST_HEAD(&image->control_pages);
135 /* Initialize the list of destination pages */
136 INIT_LIST_HEAD(&image->dest_pages);
138 /* Initialize the list of unuseable pages */
139 INIT_LIST_HEAD(&image->unuseable_pages);
141 /* Read in the segments */
142 image->nr_segments = nr_segments;
143 segment_bytes = nr_segments * sizeof(*segments);
144 result = copy_from_user(image->segment, segments, segment_bytes);
149 * Verify we have good destination addresses. The caller is
150 * responsible for making certain we don't attempt to load
151 * the new image into invalid or reserved areas of RAM. This
152 * just verifies it is an address we can use.
154 * Since the kernel does everything in page size chunks ensure
155 * the destination addreses are page aligned. Too many
156 * special cases crop of when we don't do this. The most
157 * insidious is getting overlapping destination addresses
158 * simply because addresses are changed to page size
161 result = -EADDRNOTAVAIL;
162 for (i = 0; i < nr_segments; i++) {
163 unsigned long mstart, mend;
165 mstart = image->segment[i].mem;
166 mend = mstart + image->segment[i].memsz;
167 if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
169 if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
173 /* Verify our destination addresses do not overlap.
174 * If we alloed overlapping destination addresses
175 * through very weird things can happen with no
176 * easy explanation as one segment stops on another.
179 for (i = 0; i < nr_segments; i++) {
180 unsigned long mstart, mend;
183 mstart = image->segment[i].mem;
184 mend = mstart + image->segment[i].memsz;
185 for (j = 0; j < i; j++) {
186 unsigned long pstart, pend;
187 pstart = image->segment[j].mem;
188 pend = pstart + image->segment[j].memsz;
189 /* Do the segments overlap ? */
190 if ((mend > pstart) && (mstart < pend))
195 /* Ensure our buffer sizes are strictly less than
196 * our memory sizes. This should always be the case,
197 * and it is easier to check up front than to be surprised
201 for (i = 0; i < nr_segments; i++) {
202 if (image->segment[i].bufsz > image->segment[i].memsz)
217 static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
218 unsigned long nr_segments,
219 struct kexec_segment __user *segments)
222 struct kimage *image;
224 /* Allocate and initialize a controlling structure */
226 result = do_kimage_alloc(&image, entry, nr_segments, segments);
233 * Find a location for the control code buffer, and add it
234 * the vector of segments so that it's pages will also be
235 * counted as destination pages.
238 image->control_code_page = kimage_alloc_control_pages(image,
239 get_order(KEXEC_CONTROL_CODE_SIZE));
240 if (!image->control_code_page) {
241 printk(KERN_ERR "Could not allocate control_code_buffer\n");
255 static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
256 unsigned long nr_segments,
257 struct kexec_segment __user *segments)
260 struct kimage *image;
264 /* Verify we have a valid entry point */
265 if ((entry < crashk_res.start) || (entry > crashk_res.end)) {
266 result = -EADDRNOTAVAIL;
270 /* Allocate and initialize a controlling structure */
271 result = do_kimage_alloc(&image, entry, nr_segments, segments);
275 /* Enable the special crash kernel control page
278 image->control_page = crashk_res.start;
279 image->type = KEXEC_TYPE_CRASH;
282 * Verify we have good destination addresses. Normally
283 * the caller is responsible for making certain we don't
284 * attempt to load the new image into invalid or reserved
285 * areas of RAM. But crash kernels are preloaded into a
286 * reserved area of ram. We must ensure the addresses
287 * are in the reserved area otherwise preloading the
288 * kernel could corrupt things.
290 result = -EADDRNOTAVAIL;
291 for (i = 0; i < nr_segments; i++) {
292 unsigned long mstart, mend;
294 mstart = image->segment[i].mem;
295 mend = mstart + image->segment[i].memsz - 1;
296 /* Ensure we are within the crash kernel limits */
297 if ((mstart < crashk_res.start) || (mend > crashk_res.end))
302 * Find a location for the control code buffer, and add
303 * the vector of segments so that it's pages will also be
304 * counted as destination pages.
307 image->control_code_page = kimage_alloc_control_pages(image,
308 get_order(KEXEC_CONTROL_CODE_SIZE));
309 if (!image->control_code_page) {
310 printk(KERN_ERR "Could not allocate control_code_buffer\n");
324 static int kimage_is_destination_range(struct kimage *image,
330 for (i = 0; i < image->nr_segments; i++) {
331 unsigned long mstart, mend;
333 mstart = image->segment[i].mem;
334 mend = mstart + image->segment[i].memsz;
335 if ((end > mstart) && (start < mend))
342 static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
346 pages = alloc_pages(gfp_mask, order);
348 unsigned int count, i;
349 pages->mapping = NULL;
350 set_page_private(pages, order);
352 for (i = 0; i < count; i++)
353 SetPageReserved(pages + i);
359 static void kimage_free_pages(struct page *page)
361 unsigned int order, count, i;
363 order = page_private(page);
365 for (i = 0; i < count; i++)
366 ClearPageReserved(page + i);
367 __free_pages(page, order);
370 static void kimage_free_page_list(struct list_head *list)
372 struct list_head *pos, *next;
374 list_for_each_safe(pos, next, list) {
377 page = list_entry(pos, struct page, lru);
378 list_del(&page->lru);
379 kimage_free_pages(page);
383 static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
386 /* Control pages are special, they are the intermediaries
387 * that are needed while we copy the rest of the pages
388 * to their final resting place. As such they must
389 * not conflict with either the destination addresses
390 * or memory the kernel is already using.
392 * The only case where we really need more than one of
393 * these are for architectures where we cannot disable
394 * the MMU and must instead generate an identity mapped
395 * page table for all of the memory.
397 * At worst this runs in O(N) of the image size.
399 struct list_head extra_pages;
404 INIT_LIST_HEAD(&extra_pages);
406 /* Loop while I can allocate a page and the page allocated
407 * is a destination page.
410 unsigned long pfn, epfn, addr, eaddr;
412 pages = kimage_alloc_pages(GFP_KERNEL, order);
415 pfn = page_to_pfn(pages);
417 addr = pfn << PAGE_SHIFT;
418 eaddr = epfn << PAGE_SHIFT;
419 if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
420 kimage_is_destination_range(image, addr, eaddr)) {
421 list_add(&pages->lru, &extra_pages);
427 /* Remember the allocated page... */
428 list_add(&pages->lru, &image->control_pages);
430 /* Because the page is already in it's destination
431 * location we will never allocate another page at
432 * that address. Therefore kimage_alloc_pages
433 * will not return it (again) and we don't need
434 * to give it an entry in image->segment[].
437 /* Deal with the destination pages I have inadvertently allocated.
439 * Ideally I would convert multi-page allocations into single
440 * page allocations, and add everyting to image->dest_pages.
442 * For now it is simpler to just free the pages.
444 kimage_free_page_list(&extra_pages);
449 static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
452 /* Control pages are special, they are the intermediaries
453 * that are needed while we copy the rest of the pages
454 * to their final resting place. As such they must
455 * not conflict with either the destination addresses
456 * or memory the kernel is already using.
458 * Control pages are also the only pags we must allocate
459 * when loading a crash kernel. All of the other pages
460 * are specified by the segments and we just memcpy
461 * into them directly.
463 * The only case where we really need more than one of
464 * these are for architectures where we cannot disable
465 * the MMU and must instead generate an identity mapped
466 * page table for all of the memory.
468 * Given the low demand this implements a very simple
469 * allocator that finds the first hole of the appropriate
470 * size in the reserved memory region, and allocates all
471 * of the memory up to and including the hole.
473 unsigned long hole_start, hole_end, size;
477 size = (1 << order) << PAGE_SHIFT;
478 hole_start = (image->control_page + (size - 1)) & ~(size - 1);
479 hole_end = hole_start + size - 1;
480 while (hole_end <= crashk_res.end) {
483 if (hole_end > KEXEC_CONTROL_MEMORY_LIMIT)
485 if (hole_end > crashk_res.end)
487 /* See if I overlap any of the segments */
488 for (i = 0; i < image->nr_segments; i++) {
489 unsigned long mstart, mend;
491 mstart = image->segment[i].mem;
492 mend = mstart + image->segment[i].memsz - 1;
493 if ((hole_end >= mstart) && (hole_start <= mend)) {
494 /* Advance the hole to the end of the segment */
495 hole_start = (mend + (size - 1)) & ~(size - 1);
496 hole_end = hole_start + size - 1;
500 /* If I don't overlap any segments I have found my hole! */
501 if (i == image->nr_segments) {
502 pages = pfn_to_page(hole_start >> PAGE_SHIFT);
507 image->control_page = hole_end;
513 struct page *kimage_alloc_control_pages(struct kimage *image,
516 struct page *pages = NULL;
518 switch (image->type) {
519 case KEXEC_TYPE_DEFAULT:
520 pages = kimage_alloc_normal_control_pages(image, order);
522 case KEXEC_TYPE_CRASH:
523 pages = kimage_alloc_crash_control_pages(image, order);
530 static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
532 if (*image->entry != 0)
535 if (image->entry == image->last_entry) {
536 kimage_entry_t *ind_page;
539 page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
543 ind_page = page_address(page);
544 *image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
545 image->entry = ind_page;
546 image->last_entry = ind_page +
547 ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
549 *image->entry = entry;
556 static int kimage_set_destination(struct kimage *image,
557 unsigned long destination)
561 destination &= PAGE_MASK;
562 result = kimage_add_entry(image, destination | IND_DESTINATION);
564 image->destination = destination;
570 static int kimage_add_page(struct kimage *image, unsigned long page)
575 result = kimage_add_entry(image, page | IND_SOURCE);
577 image->destination += PAGE_SIZE;
583 static void kimage_free_extra_pages(struct kimage *image)
585 /* Walk through and free any extra destination pages I may have */
586 kimage_free_page_list(&image->dest_pages);
588 /* Walk through and free any unuseable pages I have cached */
589 kimage_free_page_list(&image->unuseable_pages);
592 static void kimage_terminate(struct kimage *image)
594 if (*image->entry != 0)
597 *image->entry = IND_DONE;
600 #define for_each_kimage_entry(image, ptr, entry) \
601 for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
602 ptr = (entry & IND_INDIRECTION)? \
603 phys_to_virt((entry & PAGE_MASK)): ptr +1)
605 static void kimage_free_entry(kimage_entry_t entry)
609 page = pfn_to_page(entry >> PAGE_SHIFT);
610 kimage_free_pages(page);
613 static void kimage_free(struct kimage *image)
615 kimage_entry_t *ptr, entry;
616 kimage_entry_t ind = 0;
621 kimage_free_extra_pages(image);
622 for_each_kimage_entry(image, ptr, entry) {
623 if (entry & IND_INDIRECTION) {
624 /* Free the previous indirection page */
625 if (ind & IND_INDIRECTION)
626 kimage_free_entry(ind);
627 /* Save this indirection page until we are
632 else if (entry & IND_SOURCE)
633 kimage_free_entry(entry);
635 /* Free the final indirection page */
636 if (ind & IND_INDIRECTION)
637 kimage_free_entry(ind);
639 /* Handle any machine specific cleanup */
640 machine_kexec_cleanup(image);
642 /* Free the kexec control pages... */
643 kimage_free_page_list(&image->control_pages);
647 static kimage_entry_t *kimage_dst_used(struct kimage *image,
650 kimage_entry_t *ptr, entry;
651 unsigned long destination = 0;
653 for_each_kimage_entry(image, ptr, entry) {
654 if (entry & IND_DESTINATION)
655 destination = entry & PAGE_MASK;
656 else if (entry & IND_SOURCE) {
657 if (page == destination)
659 destination += PAGE_SIZE;
666 static struct page *kimage_alloc_page(struct kimage *image,
668 unsigned long destination)
671 * Here we implement safeguards to ensure that a source page
672 * is not copied to its destination page before the data on
673 * the destination page is no longer useful.
675 * To do this we maintain the invariant that a source page is
676 * either its own destination page, or it is not a
677 * destination page at all.
679 * That is slightly stronger than required, but the proof
680 * that no problems will not occur is trivial, and the
681 * implementation is simply to verify.
683 * When allocating all pages normally this algorithm will run
684 * in O(N) time, but in the worst case it will run in O(N^2)
685 * time. If the runtime is a problem the data structures can
692 * Walk through the list of destination pages, and see if I
695 list_for_each_entry(page, &image->dest_pages, lru) {
696 addr = page_to_pfn(page) << PAGE_SHIFT;
697 if (addr == destination) {
698 list_del(&page->lru);
706 /* Allocate a page, if we run out of memory give up */
707 page = kimage_alloc_pages(gfp_mask, 0);
710 /* If the page cannot be used file it away */
711 if (page_to_pfn(page) >
712 (KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
713 list_add(&page->lru, &image->unuseable_pages);
716 addr = page_to_pfn(page) << PAGE_SHIFT;
718 /* If it is the destination page we want use it */
719 if (addr == destination)
722 /* If the page is not a destination page use it */
723 if (!kimage_is_destination_range(image, addr,
728 * I know that the page is someones destination page.
729 * See if there is already a source page for this
730 * destination page. And if so swap the source pages.
732 old = kimage_dst_used(image, addr);
735 unsigned long old_addr;
736 struct page *old_page;
738 old_addr = *old & PAGE_MASK;
739 old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
740 copy_highpage(page, old_page);
741 *old = addr | (*old & ~PAGE_MASK);
743 /* The old page I have found cannot be a
744 * destination page, so return it.
751 /* Place the page on the destination list I
754 list_add(&page->lru, &image->dest_pages);
761 static int kimage_load_normal_segment(struct kimage *image,
762 struct kexec_segment *segment)
765 unsigned long ubytes, mbytes;
767 unsigned char __user *buf;
771 ubytes = segment->bufsz;
772 mbytes = segment->memsz;
773 maddr = segment->mem;
775 result = kimage_set_destination(image, maddr);
782 size_t uchunk, mchunk;
784 page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
789 result = kimage_add_page(image, page_to_pfn(page)
795 /* Start with a clear page */
796 memset(ptr, 0, PAGE_SIZE);
797 ptr += maddr & ~PAGE_MASK;
798 mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
806 result = copy_from_user(ptr, buf, uchunk);
809 result = (result < 0) ? result : -EIO;
821 static int kimage_load_crash_segment(struct kimage *image,
822 struct kexec_segment *segment)
824 /* For crash dumps kernels we simply copy the data from
825 * user space to it's destination.
826 * We do things a page at a time for the sake of kmap.
829 unsigned long ubytes, mbytes;
831 unsigned char __user *buf;
835 ubytes = segment->bufsz;
836 mbytes = segment->memsz;
837 maddr = segment->mem;
841 size_t uchunk, mchunk;
843 page = pfn_to_page(maddr >> PAGE_SHIFT);
849 ptr += maddr & ~PAGE_MASK;
850 mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
855 if (uchunk > ubytes) {
857 /* Zero the trailing part of the page */
858 memset(ptr + uchunk, 0, mchunk - uchunk);
860 result = copy_from_user(ptr, buf, uchunk);
861 kexec_flush_icache_page(page);
864 result = (result < 0) ? result : -EIO;
876 static int kimage_load_segment(struct kimage *image,
877 struct kexec_segment *segment)
879 int result = -ENOMEM;
881 switch (image->type) {
882 case KEXEC_TYPE_DEFAULT:
883 result = kimage_load_normal_segment(image, segment);
885 case KEXEC_TYPE_CRASH:
886 result = kimage_load_crash_segment(image, segment);
894 * Exec Kernel system call: for obvious reasons only root may call it.
896 * This call breaks up into three pieces.
897 * - A generic part which loads the new kernel from the current
898 * address space, and very carefully places the data in the
901 * - A generic part that interacts with the kernel and tells all of
902 * the devices to shut down. Preventing on-going dmas, and placing
903 * the devices in a consistent state so a later kernel can
906 * - A machine specific part that includes the syscall number
907 * and the copies the image to it's final destination. And
908 * jumps into the image at entry.
910 * kexec does not sync, or unmount filesystems so if you need
911 * that to happen you need to do that yourself.
913 struct kimage *kexec_image;
914 struct kimage *kexec_crash_image;
916 * A home grown binary mutex.
917 * Nothing can wait so this mutex is safe to use
918 * in interrupt context :)
920 static int kexec_lock;
922 asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments,
923 struct kexec_segment __user *segments,
926 struct kimage **dest_image, *image;
930 /* We only trust the superuser with rebooting the system. */
931 if (!capable(CAP_SYS_BOOT))
935 * Verify we have a legal set of flags
936 * This leaves us room for future extensions.
938 if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
941 /* Verify we are on the appropriate architecture */
942 if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
943 ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
946 /* Put an artificial cap on the number
947 * of segments passed to kexec_load.
949 if (nr_segments > KEXEC_SEGMENT_MAX)
955 /* Because we write directly to the reserved memory
956 * region when loading crash kernels we need a mutex here to
957 * prevent multiple crash kernels from attempting to load
958 * simultaneously, and to prevent a crash kernel from loading
959 * over the top of a in use crash kernel.
961 * KISS: always take the mutex.
963 locked = xchg(&kexec_lock, 1);
967 dest_image = &kexec_image;
968 if (flags & KEXEC_ON_CRASH)
969 dest_image = &kexec_crash_image;
970 if (nr_segments > 0) {
973 /* Loading another kernel to reboot into */
974 if ((flags & KEXEC_ON_CRASH) == 0)
975 result = kimage_normal_alloc(&image, entry,
976 nr_segments, segments);
977 /* Loading another kernel to switch to if this one crashes */
978 else if (flags & KEXEC_ON_CRASH) {
979 /* Free any current crash dump kernel before
982 kimage_free(xchg(&kexec_crash_image, NULL));
983 result = kimage_crash_alloc(&image, entry,
984 nr_segments, segments);
989 result = machine_kexec_prepare(image);
993 for (i = 0; i < nr_segments; i++) {
994 result = kimage_load_segment(image, &image->segment[i]);
998 kimage_terminate(image);
1000 /* Install the new kernel, and Uninstall the old */
1001 image = xchg(dest_image, image);
1004 locked = xchg(&kexec_lock, 0); /* Release the mutex */
1011 #ifdef CONFIG_COMPAT
1012 asmlinkage long compat_sys_kexec_load(unsigned long entry,
1013 unsigned long nr_segments,
1014 struct compat_kexec_segment __user *segments,
1015 unsigned long flags)
1017 struct compat_kexec_segment in;
1018 struct kexec_segment out, __user *ksegments;
1019 unsigned long i, result;
1021 /* Don't allow clients that don't understand the native
1022 * architecture to do anything.
1024 if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
1027 if (nr_segments > KEXEC_SEGMENT_MAX)
1030 ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
1031 for (i=0; i < nr_segments; i++) {
1032 result = copy_from_user(&in, &segments[i], sizeof(in));
1036 out.buf = compat_ptr(in.buf);
1037 out.bufsz = in.bufsz;
1039 out.memsz = in.memsz;
1041 result = copy_to_user(&ksegments[i], &out, sizeof(out));
1046 return sys_kexec_load(entry, nr_segments, ksegments, flags);
1050 void crash_kexec(struct pt_regs *regs)
1055 /* Take the kexec_lock here to prevent sys_kexec_load
1056 * running on one cpu from replacing the crash kernel
1057 * we are using after a panic on a different cpu.
1059 * If the crash kernel was not located in a fixed area
1060 * of memory the xchg(&kexec_crash_image) would be
1061 * sufficient. But since I reuse the memory...
1063 locked = xchg(&kexec_lock, 1);
1065 if (kexec_crash_image) {
1066 struct pt_regs fixed_regs;
1067 crash_setup_regs(&fixed_regs, regs);
1068 crash_save_vmcoreinfo();
1069 machine_crash_shutdown(&fixed_regs);
1070 machine_kexec(kexec_crash_image);
1072 locked = xchg(&kexec_lock, 0);
1077 static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
1080 struct elf_note note;
1082 note.n_namesz = strlen(name) + 1;
1083 note.n_descsz = data_len;
1085 memcpy(buf, ¬e, sizeof(note));
1086 buf += (sizeof(note) + 3)/4;
1087 memcpy(buf, name, note.n_namesz);
1088 buf += (note.n_namesz + 3)/4;
1089 memcpy(buf, data, note.n_descsz);
1090 buf += (note.n_descsz + 3)/4;
1095 static void final_note(u32 *buf)
1097 struct elf_note note;
1102 memcpy(buf, ¬e, sizeof(note));
1105 void crash_save_cpu(struct pt_regs *regs, int cpu)
1107 struct elf_prstatus prstatus;
1110 if ((cpu < 0) || (cpu >= NR_CPUS))
1113 /* Using ELF notes here is opportunistic.
1114 * I need a well defined structure format
1115 * for the data I pass, and I need tags
1116 * on the data to indicate what information I have
1117 * squirrelled away. ELF notes happen to provide
1118 * all of that, so there is no need to invent something new.
1120 buf = (u32*)per_cpu_ptr(crash_notes, cpu);
1123 memset(&prstatus, 0, sizeof(prstatus));
1124 prstatus.pr_pid = current->pid;
1125 elf_core_copy_regs(&prstatus.pr_reg, regs);
1126 buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
1127 &prstatus, sizeof(prstatus));
1131 static int __init crash_notes_memory_init(void)
1133 /* Allocate memory for saving cpu registers. */
1134 crash_notes = alloc_percpu(note_buf_t);
1136 printk("Kexec: Memory allocation for saving cpu register"
1137 " states failed\n");
1142 module_init(crash_notes_memory_init)
1146 * parsing the "crashkernel" commandline
1148 * this code is intended to be called from architecture specific code
1153 * This function parses command lines in the format
1155 * crashkernel=ramsize-range:size[,...][@offset]
1157 * The function returns 0 on success and -EINVAL on failure.
1159 static int __init parse_crashkernel_mem(char *cmdline,
1160 unsigned long long system_ram,
1161 unsigned long long *crash_size,
1162 unsigned long long *crash_base)
1164 char *cur = cmdline, *tmp;
1166 /* for each entry of the comma-separated list */
1168 unsigned long long start, end = ULLONG_MAX, size;
1170 /* get the start of the range */
1171 start = memparse(cur, &tmp);
1173 pr_warning("crashkernel: Memory value expected\n");
1178 pr_warning("crashkernel: '-' expected\n");
1183 /* if no ':' is here, than we read the end */
1185 end = memparse(cur, &tmp);
1187 pr_warning("crashkernel: Memory "
1188 "value expected\n");
1193 pr_warning("crashkernel: end <= start\n");
1199 pr_warning("crashkernel: ':' expected\n");
1204 size = memparse(cur, &tmp);
1206 pr_warning("Memory value expected\n");
1210 if (size >= system_ram) {
1211 pr_warning("crashkernel: invalid size\n");
1216 if (system_ram >= start && system_ram < end) {
1220 } while (*cur++ == ',');
1222 if (*crash_size > 0) {
1223 while (*cur != ' ' && *cur != '@')
1227 *crash_base = memparse(cur, &tmp);
1229 pr_warning("Memory value expected "
1240 * That function parses "simple" (old) crashkernel command lines like
1242 * crashkernel=size[@offset]
1244 * It returns 0 on success and -EINVAL on failure.
1246 static int __init parse_crashkernel_simple(char *cmdline,
1247 unsigned long long *crash_size,
1248 unsigned long long *crash_base)
1250 char *cur = cmdline;
1252 *crash_size = memparse(cmdline, &cur);
1253 if (cmdline == cur) {
1254 pr_warning("crashkernel: memory value expected\n");
1259 *crash_base = memparse(cur+1, &cur);
1265 * That function is the entry point for command line parsing and should be
1266 * called from the arch-specific code.
1268 int __init parse_crashkernel(char *cmdline,
1269 unsigned long long system_ram,
1270 unsigned long long *crash_size,
1271 unsigned long long *crash_base)
1273 char *p = cmdline, *ck_cmdline = NULL;
1274 char *first_colon, *first_space;
1276 BUG_ON(!crash_size || !crash_base);
1280 /* find crashkernel and use the last one if there are more */
1281 p = strstr(p, "crashkernel=");
1284 p = strstr(p+1, "crashkernel=");
1290 ck_cmdline += 12; /* strlen("crashkernel=") */
1293 * if the commandline contains a ':', then that's the extended
1294 * syntax -- if not, it must be the classic syntax
1296 first_colon = strchr(ck_cmdline, ':');
1297 first_space = strchr(ck_cmdline, ' ');
1298 if (first_colon && (!first_space || first_colon < first_space))
1299 return parse_crashkernel_mem(ck_cmdline, system_ram,
1300 crash_size, crash_base);
1302 return parse_crashkernel_simple(ck_cmdline, crash_size,
1310 void crash_save_vmcoreinfo(void)
1314 if (!vmcoreinfo_size)
1317 vmcoreinfo_append_str("CRASHTIME=%ld", get_seconds());
1319 buf = (u32 *)vmcoreinfo_note;
1321 buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
1327 void vmcoreinfo_append_str(const char *fmt, ...)
1333 va_start(args, fmt);
1334 r = vsnprintf(buf, sizeof(buf), fmt, args);
1337 if (r + vmcoreinfo_size > vmcoreinfo_max_size)
1338 r = vmcoreinfo_max_size - vmcoreinfo_size;
1340 memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
1342 vmcoreinfo_size += r;
1346 * provide an empty default implementation here -- architecture
1347 * code may override this
1349 void __attribute__ ((weak)) arch_crash_save_vmcoreinfo(void)
1352 unsigned long __attribute__ ((weak)) paddr_vmcoreinfo_note(void)
1354 return __pa((unsigned long)(char *)&vmcoreinfo_note);
1357 static int __init crash_save_vmcoreinfo_init(void)
1359 VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
1360 VMCOREINFO_PAGESIZE(PAGE_SIZE);
1362 VMCOREINFO_SYMBOL(init_uts_ns);
1363 VMCOREINFO_SYMBOL(node_online_map);
1364 VMCOREINFO_SYMBOL(swapper_pg_dir);
1365 VMCOREINFO_SYMBOL(_stext);
1367 #ifndef CONFIG_NEED_MULTIPLE_NODES
1368 VMCOREINFO_SYMBOL(mem_map);
1369 VMCOREINFO_SYMBOL(contig_page_data);
1371 #ifdef CONFIG_SPARSEMEM
1372 VMCOREINFO_SYMBOL(mem_section);
1373 VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
1374 VMCOREINFO_STRUCT_SIZE(mem_section);
1375 VMCOREINFO_OFFSET(mem_section, section_mem_map);
1377 VMCOREINFO_STRUCT_SIZE(page);
1378 VMCOREINFO_STRUCT_SIZE(pglist_data);
1379 VMCOREINFO_STRUCT_SIZE(zone);
1380 VMCOREINFO_STRUCT_SIZE(free_area);
1381 VMCOREINFO_STRUCT_SIZE(list_head);
1382 VMCOREINFO_SIZE(nodemask_t);
1383 VMCOREINFO_OFFSET(page, flags);
1384 VMCOREINFO_OFFSET(page, _count);
1385 VMCOREINFO_OFFSET(page, mapping);
1386 VMCOREINFO_OFFSET(page, lru);
1387 VMCOREINFO_OFFSET(pglist_data, node_zones);
1388 VMCOREINFO_OFFSET(pglist_data, nr_zones);
1389 #ifdef CONFIG_FLAT_NODE_MEM_MAP
1390 VMCOREINFO_OFFSET(pglist_data, node_mem_map);
1392 VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
1393 VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
1394 VMCOREINFO_OFFSET(pglist_data, node_id);
1395 VMCOREINFO_OFFSET(zone, free_area);
1396 VMCOREINFO_OFFSET(zone, vm_stat);
1397 VMCOREINFO_OFFSET(zone, spanned_pages);
1398 VMCOREINFO_OFFSET(free_area, free_list);
1399 VMCOREINFO_OFFSET(list_head, next);
1400 VMCOREINFO_OFFSET(list_head, prev);
1401 VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
1402 VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
1403 VMCOREINFO_NUMBER(NR_FREE_PAGES);
1404 VMCOREINFO_NUMBER(PG_lru);
1405 VMCOREINFO_NUMBER(PG_private);
1406 VMCOREINFO_NUMBER(PG_swapcache);
1408 arch_crash_save_vmcoreinfo();
1413 module_init(crash_save_vmcoreinfo_init)