1 // SPDX-License-Identifier: GPL-2.0-only
3 * crash.c - kernel crash support code.
4 * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
7 #include <linux/buildid.h>
8 #include <linux/init.h>
9 #include <linux/utsname.h>
10 #include <linux/vmalloc.h>
11 #include <linux/sizes.h>
12 #include <linux/kexec.h>
13 #include <linux/memory.h>
14 #include <linux/cpuhotplug.h>
15 #include <linux/memblock.h>
16 #include <linux/kexec.h>
17 #include <linux/kmemleak.h>
20 #include <asm/sections.h>
22 #include <crypto/sha1.h>
24 #include "kallsyms_internal.h"
25 #include "kexec_internal.h"
27 /* Per cpu memory for storing cpu states in case of system crash. */
28 note_buf_t __percpu *crash_notes;
30 /* vmcoreinfo stuff */
31 unsigned char *vmcoreinfo_data;
32 size_t vmcoreinfo_size;
35 /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
36 static unsigned char *vmcoreinfo_data_safecopy;
38 /* Location of the reserved area for the crash kernel */
39 struct resource crashk_res = {
40 .name = "Crash kernel",
43 .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
44 .desc = IORES_DESC_CRASH_KERNEL
46 struct resource crashk_low_res = {
47 .name = "Crash kernel",
50 .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
51 .desc = IORES_DESC_CRASH_KERNEL
55 * parsing the "crashkernel" commandline
57 * this code is intended to be called from architecture specific code
62 * This function parses command lines in the format
64 * crashkernel=ramsize-range:size[,...][@offset]
66 * The function returns 0 on success and -EINVAL on failure.
68 static int __init parse_crashkernel_mem(char *cmdline,
69 unsigned long long system_ram,
70 unsigned long long *crash_size,
71 unsigned long long *crash_base)
73 char *cur = cmdline, *tmp;
74 unsigned long long total_mem = system_ram;
77 * Firmware sometimes reserves some memory regions for its own use,
78 * so the system memory size is less than the actual physical memory
79 * size. Work around this by rounding up the total size to 128M,
80 * which is enough for most test cases.
82 total_mem = roundup(total_mem, SZ_128M);
84 /* for each entry of the comma-separated list */
86 unsigned long long start, end = ULLONG_MAX, size;
88 /* get the start of the range */
89 start = memparse(cur, &tmp);
91 pr_warn("crashkernel: Memory value expected\n");
96 pr_warn("crashkernel: '-' expected\n");
101 /* if no ':' is here, than we read the end */
103 end = memparse(cur, &tmp);
105 pr_warn("crashkernel: Memory value expected\n");
110 pr_warn("crashkernel: end <= start\n");
116 pr_warn("crashkernel: ':' expected\n");
121 size = memparse(cur, &tmp);
123 pr_warn("Memory value expected\n");
127 if (size >= total_mem) {
128 pr_warn("crashkernel: invalid size\n");
133 if (total_mem >= start && total_mem < end) {
137 } while (*cur++ == ',');
139 if (*crash_size > 0) {
140 while (*cur && *cur != ' ' && *cur != '@')
144 *crash_base = memparse(cur, &tmp);
146 pr_warn("Memory value expected after '@'\n");
151 pr_info("crashkernel size resulted in zero bytes\n");
157 * That function parses "simple" (old) crashkernel command lines like
159 * crashkernel=size[@offset]
161 * It returns 0 on success and -EINVAL on failure.
163 static int __init parse_crashkernel_simple(char *cmdline,
164 unsigned long long *crash_size,
165 unsigned long long *crash_base)
169 *crash_size = memparse(cmdline, &cur);
170 if (cmdline == cur) {
171 pr_warn("crashkernel: memory value expected\n");
176 *crash_base = memparse(cur+1, &cur);
177 else if (*cur != ' ' && *cur != '\0') {
178 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
185 #define SUFFIX_HIGH 0
187 #define SUFFIX_NULL 2
188 static __initdata char *suffix_tbl[] = {
189 [SUFFIX_HIGH] = ",high",
190 [SUFFIX_LOW] = ",low",
191 [SUFFIX_NULL] = NULL,
195 * That function parses "suffix" crashkernel command lines like
197 * crashkernel=size,[high|low]
199 * It returns 0 on success and -EINVAL on failure.
201 static int __init parse_crashkernel_suffix(char *cmdline,
202 unsigned long long *crash_size,
207 *crash_size = memparse(cmdline, &cur);
208 if (cmdline == cur) {
209 pr_warn("crashkernel: memory value expected\n");
213 /* check with suffix */
214 if (strncmp(cur, suffix, strlen(suffix))) {
215 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
218 cur += strlen(suffix);
219 if (*cur != ' ' && *cur != '\0') {
220 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
227 static __init char *get_last_crashkernel(char *cmdline,
231 char *p = cmdline, *ck_cmdline = NULL;
233 /* find crashkernel and use the last one if there are more */
236 char *end_p = strchr(p, ' ');
240 end_p = p + strlen(p);
245 /* skip the one with any known suffix */
246 for (i = 0; suffix_tbl[i]; i++) {
247 q = end_p - strlen(suffix_tbl[i]);
248 if (!strncmp(q, suffix_tbl[i],
249 strlen(suffix_tbl[i])))
254 q = end_p - strlen(suffix);
255 if (!strncmp(q, suffix, strlen(suffix)))
259 p = strstr(p+1, name);
265 static int __init __parse_crashkernel(char *cmdline,
266 unsigned long long system_ram,
267 unsigned long long *crash_size,
268 unsigned long long *crash_base,
271 char *first_colon, *first_space;
273 char *name = "crashkernel=";
275 BUG_ON(!crash_size || !crash_base);
279 ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
283 ck_cmdline += strlen(name);
286 return parse_crashkernel_suffix(ck_cmdline, crash_size,
289 * if the commandline contains a ':', then that's the extended
290 * syntax -- if not, it must be the classic syntax
292 first_colon = strchr(ck_cmdline, ':');
293 first_space = strchr(ck_cmdline, ' ');
294 if (first_colon && (!first_space || first_colon < first_space))
295 return parse_crashkernel_mem(ck_cmdline, system_ram,
296 crash_size, crash_base);
298 return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
302 * That function is the entry point for command line parsing and should be
303 * called from the arch-specific code.
305 * If crashkernel=,high|low is supported on architecture, non-NULL values
306 * should be passed to parameters 'low_size' and 'high'.
308 int __init parse_crashkernel(char *cmdline,
309 unsigned long long system_ram,
310 unsigned long long *crash_size,
311 unsigned long long *crash_base,
312 unsigned long long *low_size,
317 /* crashkernel=X[@offset] */
318 ret = __parse_crashkernel(cmdline, system_ram, crash_size,
320 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
322 * If non-NULL 'high' passed in and no normal crashkernel
323 * setting detected, try parsing crashkernel=,high|low.
325 if (high && ret == -ENOENT) {
326 ret = __parse_crashkernel(cmdline, 0, crash_size,
327 crash_base, suffix_tbl[SUFFIX_HIGH]);
328 if (ret || !*crash_size)
332 * crashkernel=Y,low can be specified or not, but invalid value
335 ret = __parse_crashkernel(cmdline, 0, low_size,
336 crash_base, suffix_tbl[SUFFIX_LOW]);
337 if (ret == -ENOENT) {
338 *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
354 * Add a dummy early_param handler to mark crashkernel= as a known command line
355 * parameter and suppress incorrect warnings in init/main.c.
357 static int __init parse_crashkernel_dummy(char *arg)
361 early_param("crashkernel", parse_crashkernel_dummy);
363 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
364 static int __init reserve_crashkernel_low(unsigned long long low_size)
367 unsigned long long low_base;
369 low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
371 pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
375 pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
376 low_base, low_base + low_size, low_size >> 20);
378 crashk_low_res.start = low_base;
379 crashk_low_res.end = low_base + low_size - 1;
380 insert_resource(&iomem_resource, &crashk_low_res);
385 void __init reserve_crashkernel_generic(char *cmdline,
386 unsigned long long crash_size,
387 unsigned long long crash_base,
388 unsigned long long crash_low_size,
391 unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
392 bool fixed_base = false;
394 /* User specifies base address explicitly. */
397 search_base = crash_base;
398 search_end = crash_base + crash_size;
400 search_base = CRASH_ADDR_LOW_MAX;
401 search_end = CRASH_ADDR_HIGH_MAX;
405 crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
406 search_base, search_end);
409 * For crashkernel=size[KMG]@offset[KMG], print out failure
410 * message if can't reserve the specified region.
413 pr_warn("crashkernel reservation failed - memory is in use.\n");
418 * For crashkernel=size[KMG], if the first attempt was for
419 * low memory, fall back to high memory, the minimum required
420 * low memory will be reserved later.
422 if (!high && search_end == CRASH_ADDR_LOW_MAX) {
423 search_end = CRASH_ADDR_HIGH_MAX;
424 search_base = CRASH_ADDR_LOW_MAX;
425 crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
430 * For crashkernel=size[KMG],high, if the first attempt was
431 * for high memory, fall back to low memory.
433 if (high && search_end == CRASH_ADDR_HIGH_MAX) {
434 search_end = CRASH_ADDR_LOW_MAX;
438 pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
443 if ((crash_base > CRASH_ADDR_LOW_MAX) &&
444 crash_low_size && reserve_crashkernel_low(crash_low_size)) {
445 memblock_phys_free(crash_base, crash_size);
449 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
450 crash_base, crash_base + crash_size, crash_size >> 20);
453 * The crashkernel memory will be removed from the kernel linear
454 * map. Inform kmemleak so that it won't try to access it.
456 kmemleak_ignore_phys(crash_base);
457 if (crashk_low_res.end)
458 kmemleak_ignore_phys(crashk_low_res.start);
460 crashk_res.start = crash_base;
461 crashk_res.end = crash_base + crash_size - 1;
462 insert_resource(&iomem_resource, &crashk_res);
466 int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
467 void **addr, unsigned long *sz)
471 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
474 unsigned long long notes_addr;
475 unsigned long mstart, mend;
477 /* extra phdr for vmcoreinfo ELF note */
478 nr_phdr = nr_cpus + 1;
479 nr_phdr += mem->nr_ranges;
482 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
483 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
484 * I think this is required by tools like gdb. So same physical
485 * memory will be mapped in two ELF headers. One will contain kernel
486 * text virtual addresses and other will have __va(physical) addresses.
490 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
491 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
493 buf = vzalloc(elf_sz);
497 ehdr = (Elf64_Ehdr *)buf;
498 phdr = (Elf64_Phdr *)(ehdr + 1);
499 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
500 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
501 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
502 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
503 ehdr->e_ident[EI_OSABI] = ELF_OSABI;
504 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
505 ehdr->e_type = ET_CORE;
506 ehdr->e_machine = ELF_ARCH;
507 ehdr->e_version = EV_CURRENT;
508 ehdr->e_phoff = sizeof(Elf64_Ehdr);
509 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
510 ehdr->e_phentsize = sizeof(Elf64_Phdr);
512 /* Prepare one phdr of type PT_NOTE for each possible CPU */
513 for_each_possible_cpu(cpu) {
514 phdr->p_type = PT_NOTE;
515 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
516 phdr->p_offset = phdr->p_paddr = notes_addr;
517 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
522 /* Prepare one PT_NOTE header for vmcoreinfo */
523 phdr->p_type = PT_NOTE;
524 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
525 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
529 /* Prepare PT_LOAD type program header for kernel text region */
530 if (need_kernel_map) {
531 phdr->p_type = PT_LOAD;
532 phdr->p_flags = PF_R|PF_W|PF_X;
533 phdr->p_vaddr = (unsigned long) _text;
534 phdr->p_filesz = phdr->p_memsz = _end - _text;
535 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
540 /* Go through all the ranges in mem->ranges[] and prepare phdr */
541 for (i = 0; i < mem->nr_ranges; i++) {
542 mstart = mem->ranges[i].start;
543 mend = mem->ranges[i].end;
545 phdr->p_type = PT_LOAD;
546 phdr->p_flags = PF_R|PF_W|PF_X;
547 phdr->p_offset = mstart;
549 phdr->p_paddr = mstart;
550 phdr->p_vaddr = (unsigned long) __va(mstart);
551 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
554 pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
555 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
556 ehdr->e_phnum, phdr->p_offset);
565 int crash_exclude_mem_range(struct crash_mem *mem,
566 unsigned long long mstart, unsigned long long mend)
569 unsigned long long start, end, p_start, p_end;
570 struct range temp_range = {0, 0};
572 for (i = 0; i < mem->nr_ranges; i++) {
573 start = mem->ranges[i].start;
574 end = mem->ranges[i].end;
578 if (mstart > end || mend < start)
581 /* Truncate any area outside of range */
587 /* Found completely overlapping range */
588 if (p_start == start && p_end == end) {
589 mem->ranges[i].start = 0;
590 mem->ranges[i].end = 0;
591 if (i < mem->nr_ranges - 1) {
592 /* Shift rest of the ranges to left */
593 for (j = i; j < mem->nr_ranges - 1; j++) {
594 mem->ranges[j].start =
595 mem->ranges[j+1].start;
597 mem->ranges[j+1].end;
601 * Continue to check if there are another overlapping ranges
602 * from the current position because of shifting the above
613 if (p_start > start && p_end < end) {
614 /* Split original range */
615 mem->ranges[i].end = p_start - 1;
616 temp_range.start = p_end + 1;
617 temp_range.end = end;
618 } else if (p_start != start)
619 mem->ranges[i].end = p_start - 1;
621 mem->ranges[i].start = p_end + 1;
625 /* If a split happened, add the split to array */
630 if (i == mem->max_nr_ranges - 1)
633 /* Location where new range should go */
635 if (j < mem->nr_ranges) {
636 /* Move over all ranges one slot towards the end */
637 for (i = mem->nr_ranges - 1; i >= j; i--)
638 mem->ranges[i + 1] = mem->ranges[i];
641 mem->ranges[j].start = temp_range.start;
642 mem->ranges[j].end = temp_range.end;
647 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
648 void *data, size_t data_len)
650 struct elf_note *note = (struct elf_note *)buf;
652 note->n_namesz = strlen(name) + 1;
653 note->n_descsz = data_len;
655 buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
656 memcpy(buf, name, note->n_namesz);
657 buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
658 memcpy(buf, data, data_len);
659 buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
664 void final_note(Elf_Word *buf)
666 memset(buf, 0, sizeof(struct elf_note));
669 static void update_vmcoreinfo_note(void)
671 u32 *buf = vmcoreinfo_note;
673 if (!vmcoreinfo_size)
675 buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
680 void crash_update_vmcoreinfo_safecopy(void *ptr)
683 memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
685 vmcoreinfo_data_safecopy = ptr;
688 void crash_save_vmcoreinfo(void)
690 if (!vmcoreinfo_note)
693 /* Use the safe copy to generate vmcoreinfo note if have */
694 if (vmcoreinfo_data_safecopy)
695 vmcoreinfo_data = vmcoreinfo_data_safecopy;
697 vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
698 update_vmcoreinfo_note();
701 void vmcoreinfo_append_str(const char *fmt, ...)
708 r = vscnprintf(buf, sizeof(buf), fmt, args);
711 r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);
713 memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
715 vmcoreinfo_size += r;
717 WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES,
718 "vmcoreinfo data exceeds allocated size, truncating");
722 * provide an empty default implementation here -- architecture
723 * code may override this
725 void __weak arch_crash_save_vmcoreinfo(void)
728 phys_addr_t __weak paddr_vmcoreinfo_note(void)
730 return __pa(vmcoreinfo_note);
732 EXPORT_SYMBOL(paddr_vmcoreinfo_note);
734 static int __init crash_save_vmcoreinfo_init(void)
736 vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
737 if (!vmcoreinfo_data) {
738 pr_warn("Memory allocation for vmcoreinfo_data failed\n");
742 vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
743 GFP_KERNEL | __GFP_ZERO);
744 if (!vmcoreinfo_note) {
745 free_page((unsigned long)vmcoreinfo_data);
746 vmcoreinfo_data = NULL;
747 pr_warn("Memory allocation for vmcoreinfo_note failed\n");
751 VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
752 VMCOREINFO_BUILD_ID();
753 VMCOREINFO_PAGESIZE(PAGE_SIZE);
755 VMCOREINFO_SYMBOL(init_uts_ns);
756 VMCOREINFO_OFFSET(uts_namespace, name);
757 VMCOREINFO_SYMBOL(node_online_map);
759 VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
761 VMCOREINFO_SYMBOL(_stext);
762 VMCOREINFO_SYMBOL(vmap_area_list);
765 VMCOREINFO_SYMBOL(mem_map);
766 VMCOREINFO_SYMBOL(contig_page_data);
768 #ifdef CONFIG_SPARSEMEM
769 VMCOREINFO_SYMBOL_ARRAY(mem_section);
770 VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
771 VMCOREINFO_STRUCT_SIZE(mem_section);
772 VMCOREINFO_OFFSET(mem_section, section_mem_map);
773 VMCOREINFO_NUMBER(SECTION_SIZE_BITS);
774 VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
776 VMCOREINFO_STRUCT_SIZE(page);
777 VMCOREINFO_STRUCT_SIZE(pglist_data);
778 VMCOREINFO_STRUCT_SIZE(zone);
779 VMCOREINFO_STRUCT_SIZE(free_area);
780 VMCOREINFO_STRUCT_SIZE(list_head);
781 VMCOREINFO_SIZE(nodemask_t);
782 VMCOREINFO_OFFSET(page, flags);
783 VMCOREINFO_OFFSET(page, _refcount);
784 VMCOREINFO_OFFSET(page, mapping);
785 VMCOREINFO_OFFSET(page, lru);
786 VMCOREINFO_OFFSET(page, _mapcount);
787 VMCOREINFO_OFFSET(page, private);
788 VMCOREINFO_OFFSET(page, compound_head);
789 VMCOREINFO_OFFSET(pglist_data, node_zones);
790 VMCOREINFO_OFFSET(pglist_data, nr_zones);
791 #ifdef CONFIG_FLATMEM
792 VMCOREINFO_OFFSET(pglist_data, node_mem_map);
794 VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
795 VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
796 VMCOREINFO_OFFSET(pglist_data, node_id);
797 VMCOREINFO_OFFSET(zone, free_area);
798 VMCOREINFO_OFFSET(zone, vm_stat);
799 VMCOREINFO_OFFSET(zone, spanned_pages);
800 VMCOREINFO_OFFSET(free_area, free_list);
801 VMCOREINFO_OFFSET(list_head, next);
802 VMCOREINFO_OFFSET(list_head, prev);
803 VMCOREINFO_OFFSET(vmap_area, va_start);
804 VMCOREINFO_OFFSET(vmap_area, list);
805 VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER + 1);
806 log_buf_vmcoreinfo_setup();
807 VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
808 VMCOREINFO_NUMBER(NR_FREE_PAGES);
809 VMCOREINFO_NUMBER(PG_lru);
810 VMCOREINFO_NUMBER(PG_private);
811 VMCOREINFO_NUMBER(PG_swapcache);
812 VMCOREINFO_NUMBER(PG_swapbacked);
813 VMCOREINFO_NUMBER(PG_slab);
814 #ifdef CONFIG_MEMORY_FAILURE
815 VMCOREINFO_NUMBER(PG_hwpoison);
817 VMCOREINFO_NUMBER(PG_head_mask);
818 #define PAGE_BUDDY_MAPCOUNT_VALUE (~PG_buddy)
819 VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
820 #ifdef CONFIG_HUGETLB_PAGE
821 VMCOREINFO_NUMBER(PG_hugetlb);
822 #define PAGE_OFFLINE_MAPCOUNT_VALUE (~PG_offline)
823 VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
826 #ifdef CONFIG_KALLSYMS
827 VMCOREINFO_SYMBOL(kallsyms_names);
828 VMCOREINFO_SYMBOL(kallsyms_num_syms);
829 VMCOREINFO_SYMBOL(kallsyms_token_table);
830 VMCOREINFO_SYMBOL(kallsyms_token_index);
831 #ifdef CONFIG_KALLSYMS_BASE_RELATIVE
832 VMCOREINFO_SYMBOL(kallsyms_offsets);
833 VMCOREINFO_SYMBOL(kallsyms_relative_base);
835 VMCOREINFO_SYMBOL(kallsyms_addresses);
836 #endif /* CONFIG_KALLSYMS_BASE_RELATIVE */
837 #endif /* CONFIG_KALLSYMS */
839 arch_crash_save_vmcoreinfo();
840 update_vmcoreinfo_note();
845 subsys_initcall(crash_save_vmcoreinfo_init);
847 static int __init crash_notes_memory_init(void)
849 /* Allocate memory for saving cpu registers. */
853 * crash_notes could be allocated across 2 vmalloc pages when percpu
854 * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
855 * pages are also on 2 continuous physical pages. In this case the
856 * 2nd part of crash_notes in 2nd page could be lost since only the
857 * starting address and size of crash_notes are exported through sysfs.
858 * Here round up the size of crash_notes to the nearest power of two
859 * and pass it to __alloc_percpu as align value. This can make sure
860 * crash_notes is allocated inside one physical page.
862 size = sizeof(note_buf_t);
863 align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
866 * Break compile if size is bigger than PAGE_SIZE since crash_notes
867 * definitely will be in 2 pages with that.
869 BUILD_BUG_ON(size > PAGE_SIZE);
871 crash_notes = __alloc_percpu(size, align);
873 pr_warn("Memory allocation for saving cpu register states failed\n");
878 subsys_initcall(crash_notes_memory_init);
880 #ifdef CONFIG_CRASH_HOTPLUG
882 #define pr_fmt(fmt) "crash hp: " fmt
885 * Different than kexec/kdump loading/unloading/jumping/shrinking which
886 * usually rarely happen, there will be many crash hotplug events notified
887 * during one short period, e.g one memory board is hot added and memory
888 * regions are online. So mutex lock __crash_hotplug_lock is used to
889 * serialize the crash hotplug handling specifically.
891 DEFINE_MUTEX(__crash_hotplug_lock);
892 #define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock)
893 #define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock)
896 * This routine utilized when the crash_hotplug sysfs node is read.
897 * It reflects the kernel's ability/permission to update the crash
898 * elfcorehdr directly.
900 int crash_check_update_elfcorehdr(void)
904 crash_hotplug_lock();
905 /* Obtain lock while reading crash information */
906 if (!kexec_trylock()) {
907 pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
908 crash_hotplug_unlock();
911 if (kexec_crash_image) {
912 if (kexec_crash_image->file_mode)
915 rc = kexec_crash_image->update_elfcorehdr;
917 /* Release lock now that update complete */
919 crash_hotplug_unlock();
925 * To accurately reflect hot un/plug changes of cpu and memory resources
926 * (including onling and offlining of those resources), the elfcorehdr
927 * (which is passed to the crash kernel via the elfcorehdr= parameter)
928 * must be updated with the new list of CPUs and memories.
930 * In order to make changes to elfcorehdr, two conditions are needed:
931 * First, the segment containing the elfcorehdr must be large enough
932 * to permit a growing number of resources; the elfcorehdr memory size
933 * is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES.
934 * Second, purgatory must explicitly exclude the elfcorehdr from the
935 * list of segments it checks (since the elfcorehdr changes and thus
936 * would require an update to purgatory itself to update the digest).
938 static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
940 struct kimage *image;
942 crash_hotplug_lock();
943 /* Obtain lock while changing crash information */
944 if (!kexec_trylock()) {
945 pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
946 crash_hotplug_unlock();
950 /* Check kdump is not loaded */
951 if (!kexec_crash_image)
954 image = kexec_crash_image;
956 /* Check that updating elfcorehdr is permitted */
957 if (!(image->file_mode || image->update_elfcorehdr))
960 if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
961 hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
962 pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
964 pr_debug("hp_action %u\n", hp_action);
967 * The elfcorehdr_index is set to -1 when the struct kimage
968 * is allocated. Find the segment containing the elfcorehdr,
969 * if not already found.
971 if (image->elfcorehdr_index < 0) {
976 for (n = 0; n < image->nr_segments; n++) {
977 mem = image->segment[n].mem;
978 ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
980 /* The segment containing elfcorehdr */
981 if (memcmp(ptr, ELFMAG, SELFMAG) == 0)
982 image->elfcorehdr_index = (int)n;
988 if (image->elfcorehdr_index < 0) {
989 pr_err("unable to locate elfcorehdr segment");
993 /* Needed in order for the segments to be updated */
994 arch_kexec_unprotect_crashkres();
996 /* Differentiate between normal load and hotplug update */
997 image->hp_action = hp_action;
999 /* Now invoke arch-specific update handler */
1000 arch_crash_handle_hotplug_event(image);
1002 /* No longer handling a hotplug event */
1003 image->hp_action = KEXEC_CRASH_HP_NONE;
1004 image->elfcorehdr_updated = true;
1006 /* Change back to read-only */
1007 arch_kexec_protect_crashkres();
1009 /* Errors in the callback is not a reason to rollback state */
1011 /* Release lock now that update complete */
1013 crash_hotplug_unlock();
1016 static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
1020 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
1021 KEXEC_CRASH_HP_INVALID_CPU);
1025 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
1026 KEXEC_CRASH_HP_INVALID_CPU);
1032 static struct notifier_block crash_memhp_nb = {
1033 .notifier_call = crash_memhp_notifier,
1037 static int crash_cpuhp_online(unsigned int cpu)
1039 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
1043 static int crash_cpuhp_offline(unsigned int cpu)
1045 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
1049 static int __init crash_hotplug_init(void)
1053 if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
1054 register_memory_notifier(&crash_memhp_nb);
1056 if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
1057 result = cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN,
1058 "crash/cpuhp", crash_cpuhp_online, crash_cpuhp_offline);
1064 subsys_initcall(crash_hotplug_init);