1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * crash.c - kernel crash support code.
4 * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
5 */
6
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>
18
19#include <asm/page.h>
20#include <asm/sections.h>
21
22#include <crypto/sha1.h>
23
24#include "kallsyms_internal.h"
25#include "kexec_internal.h"
26
27/* Per cpu memory for storing cpu states in case of system crash. */
28note_buf_t __percpu *crash_notes;
29
30/* vmcoreinfo stuff */
31unsigned char *vmcoreinfo_data;
32size_t vmcoreinfo_size;
33u32 *vmcoreinfo_note;
34
35/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
36static unsigned char *vmcoreinfo_data_safecopy;
37
38/* Location of the reserved area for the crash kernel */
39struct resource crashk_res = {
40 .name = "Crash kernel",
41 .start = 0,
42 .end = 0,
43 .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
44 .desc = IORES_DESC_CRASH_KERNEL
45};
46struct resource crashk_low_res = {
47 .name = "Crash kernel",
48 .start = 0,
49 .end = 0,
50 .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
51 .desc = IORES_DESC_CRASH_KERNEL
52};
53
54/*
55 * parsing the "crashkernel" commandline
56 *
57 * this code is intended to be called from architecture specific code
58 */
59
60
61/*
62 * This function parses command lines in the format
63 *
64 * crashkernel=ramsize-range:size[,...][@offset]
65 *
66 * The function returns 0 on success and -EINVAL on failure.
67 */
68static 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)
72{
73 char *cur = cmdline, *tmp;
74 unsigned long long total_mem = system_ram;
75
76 /*
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.
81 */
82 total_mem = roundup(total_mem, SZ_128M);
83
84 /* for each entry of the comma-separated list */
85 do {
86 unsigned long long start, end = ULLONG_MAX, size;
87
88 /* get the start of the range */
89 start = memparse(ptr: cur, retptr: &tmp);
90 if (cur == tmp) {
91 pr_warn("crashkernel: Memory value expected\n");
92 return -EINVAL;
93 }
94 cur = tmp;
95 if (*cur != '-') {
96 pr_warn("crashkernel: '-' expected\n");
97 return -EINVAL;
98 }
99 cur++;
100
101 /* if no ':' is here, than we read the end */
102 if (*cur != ':') {
103 end = memparse(ptr: cur, retptr: &tmp);
104 if (cur == tmp) {
105 pr_warn("crashkernel: Memory value expected\n");
106 return -EINVAL;
107 }
108 cur = tmp;
109 if (end <= start) {
110 pr_warn("crashkernel: end <= start\n");
111 return -EINVAL;
112 }
113 }
114
115 if (*cur != ':') {
116 pr_warn("crashkernel: ':' expected\n");
117 return -EINVAL;
118 }
119 cur++;
120
121 size = memparse(ptr: cur, retptr: &tmp);
122 if (cur == tmp) {
123 pr_warn("Memory value expected\n");
124 return -EINVAL;
125 }
126 cur = tmp;
127 if (size >= total_mem) {
128 pr_warn("crashkernel: invalid size\n");
129 return -EINVAL;
130 }
131
132 /* match ? */
133 if (total_mem >= start && total_mem < end) {
134 *crash_size = size;
135 break;
136 }
137 } while (*cur++ == ',');
138
139 if (*crash_size > 0) {
140 while (*cur && *cur != ' ' && *cur != '@')
141 cur++;
142 if (*cur == '@') {
143 cur++;
144 *crash_base = memparse(ptr: cur, retptr: &tmp);
145 if (cur == tmp) {
146 pr_warn("Memory value expected after '@'\n");
147 return -EINVAL;
148 }
149 }
150 } else
151 pr_info("crashkernel size resulted in zero bytes\n");
152
153 return 0;
154}
155
156/*
157 * That function parses "simple" (old) crashkernel command lines like
158 *
159 * crashkernel=size[@offset]
160 *
161 * It returns 0 on success and -EINVAL on failure.
162 */
163static int __init parse_crashkernel_simple(char *cmdline,
164 unsigned long long *crash_size,
165 unsigned long long *crash_base)
166{
167 char *cur = cmdline;
168
169 *crash_size = memparse(ptr: cmdline, retptr: &cur);
170 if (cmdline == cur) {
171 pr_warn("crashkernel: memory value expected\n");
172 return -EINVAL;
173 }
174
175 if (*cur == '@')
176 *crash_base = memparse(ptr: cur+1, retptr: &cur);
177 else if (*cur != ' ' && *cur != '\0') {
178 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
179 return -EINVAL;
180 }
181
182 return 0;
183}
184
185#define SUFFIX_HIGH 0
186#define SUFFIX_LOW 1
187#define SUFFIX_NULL 2
188static __initdata char *suffix_tbl[] = {
189 [SUFFIX_HIGH] = ",high",
190 [SUFFIX_LOW] = ",low",
191 [SUFFIX_NULL] = NULL,
192};
193
194/*
195 * That function parses "suffix" crashkernel command lines like
196 *
197 * crashkernel=size,[high|low]
198 *
199 * It returns 0 on success and -EINVAL on failure.
200 */
201static int __init parse_crashkernel_suffix(char *cmdline,
202 unsigned long long *crash_size,
203 const char *suffix)
204{
205 char *cur = cmdline;
206
207 *crash_size = memparse(ptr: cmdline, retptr: &cur);
208 if (cmdline == cur) {
209 pr_warn("crashkernel: memory value expected\n");
210 return -EINVAL;
211 }
212
213 /* check with suffix */
214 if (strncmp(cur, suffix, strlen(suffix))) {
215 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
216 return -EINVAL;
217 }
218 cur += strlen(suffix);
219 if (*cur != ' ' && *cur != '\0') {
220 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
221 return -EINVAL;
222 }
223
224 return 0;
225}
226
227static __init char *get_last_crashkernel(char *cmdline,
228 const char *name,
229 const char *suffix)
230{
231 char *p = cmdline, *ck_cmdline = NULL;
232
233 /* find crashkernel and use the last one if there are more */
234 p = strstr(p, name);
235 while (p) {
236 char *end_p = strchr(p, ' ');
237 char *q;
238
239 if (!end_p)
240 end_p = p + strlen(p);
241
242 if (!suffix) {
243 int i;
244
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])))
250 goto next;
251 }
252 ck_cmdline = p;
253 } else {
254 q = end_p - strlen(suffix);
255 if (!strncmp(q, suffix, strlen(suffix)))
256 ck_cmdline = p;
257 }
258next:
259 p = strstr(p+1, name);
260 }
261
262 return ck_cmdline;
263}
264
265static int __init __parse_crashkernel(char *cmdline,
266 unsigned long long system_ram,
267 unsigned long long *crash_size,
268 unsigned long long *crash_base,
269 const char *suffix)
270{
271 char *first_colon, *first_space;
272 char *ck_cmdline;
273 char *name = "crashkernel=";
274
275 BUG_ON(!crash_size || !crash_base);
276 *crash_size = 0;
277 *crash_base = 0;
278
279 ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
280 if (!ck_cmdline)
281 return -ENOENT;
282
283 ck_cmdline += strlen(name);
284
285 if (suffix)
286 return parse_crashkernel_suffix(cmdline: ck_cmdline, crash_size,
287 suffix);
288 /*
289 * if the commandline contains a ':', then that's the extended
290 * syntax -- if not, it must be the classic syntax
291 */
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(cmdline: ck_cmdline, system_ram,
296 crash_size, crash_base);
297
298 return parse_crashkernel_simple(cmdline: ck_cmdline, crash_size, crash_base);
299}
300
301/*
302 * That function is the entry point for command line parsing and should be
303 * called from the arch-specific code.
304 *
305 * If crashkernel=,high|low is supported on architecture, non-NULL values
306 * should be passed to parameters 'low_size' and 'high'.
307 */
308int __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,
313 bool *high)
314{
315 int ret;
316
317 /* crashkernel=X[@offset] */
318 ret = __parse_crashkernel(cmdline, system_ram, crash_size,
319 crash_base, NULL);
320#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
321 /*
322 * If non-NULL 'high' passed in and no normal crashkernel
323 * setting detected, try parsing crashkernel=,high|low.
324 */
325 if (high && ret == -ENOENT) {
326 ret = __parse_crashkernel(cmdline, system_ram: 0, crash_size,
327 crash_base, suffix: suffix_tbl[SUFFIX_HIGH]);
328 if (ret || !*crash_size)
329 return -EINVAL;
330
331 /*
332 * crashkernel=Y,low can be specified or not, but invalid value
333 * is not allowed.
334 */
335 ret = __parse_crashkernel(cmdline, system_ram: 0, crash_size: low_size,
336 crash_base, suffix: suffix_tbl[SUFFIX_LOW]);
337 if (ret == -ENOENT) {
338 *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
339 ret = 0;
340 } else if (ret) {
341 return ret;
342 }
343
344 *high = true;
345 }
346#endif
347 if (!*crash_size)
348 ret = -EINVAL;
349
350 return ret;
351}
352
353/*
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.
356 */
357static int __init parse_crashkernel_dummy(char *arg)
358{
359 return 0;
360}
361early_param("crashkernel", parse_crashkernel_dummy);
362
363#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
364static int __init reserve_crashkernel_low(unsigned long long low_size)
365{
366#ifdef CONFIG_64BIT
367 unsigned long long low_base;
368
369 low_base = memblock_phys_alloc_range(size: low_size, CRASH_ALIGN, start: 0, CRASH_ADDR_LOW_MAX);
370 if (!low_base) {
371 pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
372 return -ENOMEM;
373 }
374
375 pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
376 low_base, low_base + low_size, low_size >> 20);
377
378 crashk_low_res.start = low_base;
379 crashk_low_res.end = low_base + low_size - 1;
380 insert_resource(parent: &iomem_resource, new: &crashk_low_res);
381#endif
382 return 0;
383}
384
385void __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,
389 bool high)
390{
391 unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
392 bool fixed_base = false;
393
394 /* User specifies base address explicitly. */
395 if (crash_base) {
396 fixed_base = true;
397 search_base = crash_base;
398 search_end = crash_base + crash_size;
399 } else if (high) {
400 search_base = CRASH_ADDR_LOW_MAX;
401 search_end = CRASH_ADDR_HIGH_MAX;
402 }
403
404retry:
405 crash_base = memblock_phys_alloc_range(size: crash_size, CRASH_ALIGN,
406 start: search_base, end: search_end);
407 if (!crash_base) {
408 /*
409 * For crashkernel=size[KMG]@offset[KMG], print out failure
410 * message if can't reserve the specified region.
411 */
412 if (fixed_base) {
413 pr_warn("crashkernel reservation failed - memory is in use.\n");
414 return;
415 }
416
417 /*
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.
421 */
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;
426 goto retry;
427 }
428
429 /*
430 * For crashkernel=size[KMG],high, if the first attempt was
431 * for high memory, fall back to low memory.
432 */
433 if (high && search_end == CRASH_ADDR_HIGH_MAX) {
434 search_end = CRASH_ADDR_LOW_MAX;
435 search_base = 0;
436 goto retry;
437 }
438 pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
439 crash_size);
440 return;
441 }
442
443 if ((crash_base > CRASH_ADDR_LOW_MAX) &&
444 crash_low_size && reserve_crashkernel_low(low_size: crash_low_size)) {
445 memblock_phys_free(base: crash_base, size: crash_size);
446 return;
447 }
448
449 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
450 crash_base, crash_base + crash_size, crash_size >> 20);
451
452 /*
453 * The crashkernel memory will be removed from the kernel linear
454 * map. Inform kmemleak so that it won't try to access it.
455 */
456 kmemleak_ignore_phys(phys: crash_base);
457 if (crashk_low_res.end)
458 kmemleak_ignore_phys(phys: crashk_low_res.start);
459
460 crashk_res.start = crash_base;
461 crashk_res.end = crash_base + crash_size - 1;
462 insert_resource(parent: &iomem_resource, new: &crashk_res);
463}
464#endif
465
466int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
467 void **addr, unsigned long *sz)
468{
469 Elf64_Ehdr *ehdr;
470 Elf64_Phdr *phdr;
471 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
472 unsigned char *buf;
473 unsigned int cpu, i;
474 unsigned long long notes_addr;
475 unsigned long mstart, mend;
476
477 /* extra phdr for vmcoreinfo ELF note */
478 nr_phdr = nr_cpus + 1;
479 nr_phdr += mem->nr_ranges;
480
481 /*
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.
487 */
488
489 nr_phdr++;
490 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
491 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
492
493 buf = vzalloc(size: elf_sz);
494 if (!buf)
495 return -ENOMEM;
496
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);
511
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);
518 (ehdr->e_phnum)++;
519 phdr++;
520 }
521
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;
526 (ehdr->e_phnum)++;
527 phdr++;
528
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);
536 ehdr->e_phnum++;
537 phdr++;
538 }
539
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;
544
545 phdr->p_type = PT_LOAD;
546 phdr->p_flags = PF_R|PF_W|PF_X;
547 phdr->p_offset = mstart;
548
549 phdr->p_paddr = mstart;
550 phdr->p_vaddr = (unsigned long) __va(mstart);
551 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
552 phdr->p_align = 0;
553 ehdr->e_phnum++;
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);
557 phdr++;
558 }
559
560 *addr = buf;
561 *sz = elf_sz;
562 return 0;
563}
564
565int crash_exclude_mem_range(struct crash_mem *mem,
566 unsigned long long mstart, unsigned long long mend)
567{
568 int i, j;
569 unsigned long long start, end, p_start, p_end;
570 struct range temp_range = {0, 0};
571
572 for (i = 0; i < mem->nr_ranges; i++) {
573 start = mem->ranges[i].start;
574 end = mem->ranges[i].end;
575 p_start = mstart;
576 p_end = mend;
577
578 if (mstart > end || mend < start)
579 continue;
580
581 /* Truncate any area outside of range */
582 if (mstart < start)
583 p_start = start;
584 if (mend > end)
585 p_end = end;
586
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;
596 mem->ranges[j].end =
597 mem->ranges[j+1].end;
598 }
599
600 /*
601 * Continue to check if there are another overlapping ranges
602 * from the current position because of shifting the above
603 * mem ranges.
604 */
605 i--;
606 mem->nr_ranges--;
607 continue;
608 }
609 mem->nr_ranges--;
610 return 0;
611 }
612
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;
620 else
621 mem->ranges[i].start = p_end + 1;
622 break;
623 }
624
625 /* If a split happened, add the split to array */
626 if (!temp_range.end)
627 return 0;
628
629 /* Split happened */
630 if (i == mem->max_nr_ranges - 1)
631 return -ENOMEM;
632
633 /* Location where new range should go */
634 j = i + 1;
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];
639 }
640
641 mem->ranges[j].start = temp_range.start;
642 mem->ranges[j].end = temp_range.end;
643 mem->nr_ranges++;
644 return 0;
645}
646
647Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
648 void *data, size_t data_len)
649{
650 struct elf_note *note = (struct elf_note *)buf;
651
652 note->n_namesz = strlen(name) + 1;
653 note->n_descsz = data_len;
654 note->n_type = type;
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));
660
661 return buf;
662}
663
664void final_note(Elf_Word *buf)
665{
666 memset(buf, 0, sizeof(struct elf_note));
667}
668
669static void update_vmcoreinfo_note(void)
670{
671 u32 *buf = vmcoreinfo_note;
672
673 if (!vmcoreinfo_size)
674 return;
675 buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, type: 0, data: vmcoreinfo_data,
676 data_len: vmcoreinfo_size);
677 final_note(buf);
678}
679
680void crash_update_vmcoreinfo_safecopy(void *ptr)
681{
682 if (ptr)
683 memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
684
685 vmcoreinfo_data_safecopy = ptr;
686}
687
688void crash_save_vmcoreinfo(void)
689{
690 if (!vmcoreinfo_note)
691 return;
692
693 /* Use the safe copy to generate vmcoreinfo note if have */
694 if (vmcoreinfo_data_safecopy)
695 vmcoreinfo_data = vmcoreinfo_data_safecopy;
696
697 vmcoreinfo_append_str(fmt: "CRASHTIME=%lld\n", ktime_get_real_seconds());
698 update_vmcoreinfo_note();
699}
700
701void vmcoreinfo_append_str(const char *fmt, ...)
702{
703 va_list args;
704 char buf[0x50];
705 size_t r;
706
707 va_start(args, fmt);
708 r = vscnprintf(buf, size: sizeof(buf), fmt, args);
709 va_end(args);
710
711 r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);
712
713 memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
714
715 vmcoreinfo_size += r;
716
717 WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES,
718 "vmcoreinfo data exceeds allocated size, truncating");
719}
720
721/*
722 * provide an empty default implementation here -- architecture
723 * code may override this
724 */
725void __weak arch_crash_save_vmcoreinfo(void)
726{}
727
728phys_addr_t __weak paddr_vmcoreinfo_note(void)
729{
730 return __pa(vmcoreinfo_note);
731}
732EXPORT_SYMBOL(paddr_vmcoreinfo_note);
733
734static int __init crash_save_vmcoreinfo_init(void)
735{
736 vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
737 if (!vmcoreinfo_data) {
738 pr_warn("Memory allocation for vmcoreinfo_data failed\n");
739 return -ENOMEM;
740 }
741
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");
748 return -ENOMEM;
749 }
750
751 VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
752 VMCOREINFO_BUILD_ID();
753 VMCOREINFO_PAGESIZE(PAGE_SIZE);
754
755 VMCOREINFO_SYMBOL(init_uts_ns);
756 VMCOREINFO_OFFSET(uts_namespace, name);
757 VMCOREINFO_SYMBOL(node_online_map);
758#ifdef CONFIG_MMU
759 VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
760#endif
761 VMCOREINFO_SYMBOL(_stext);
762 VMCOREINFO_SYMBOL(vmap_area_list);
763
764#ifndef CONFIG_NUMA
765 VMCOREINFO_SYMBOL(mem_map);
766 VMCOREINFO_SYMBOL(contig_page_data);
767#endif
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);
775#endif
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);
793#endif
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);
816#endif
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);
824#endif
825
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);
834#else
835 VMCOREINFO_SYMBOL(kallsyms_addresses);
836#endif /* CONFIG_KALLSYMS_BASE_RELATIVE */
837#endif /* CONFIG_KALLSYMS */
838
839 arch_crash_save_vmcoreinfo();
840 update_vmcoreinfo_note();
841
842 return 0;
843}
844
845subsys_initcall(crash_save_vmcoreinfo_init);
846
847static int __init crash_notes_memory_init(void)
848{
849 /* Allocate memory for saving cpu registers. */
850 size_t size, align;
851
852 /*
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.
861 */
862 size = sizeof(note_buf_t);
863 align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
864
865 /*
866 * Break compile if size is bigger than PAGE_SIZE since crash_notes
867 * definitely will be in 2 pages with that.
868 */
869 BUILD_BUG_ON(size > PAGE_SIZE);
870
871 crash_notes = __alloc_percpu(size, align);
872 if (!crash_notes) {
873 pr_warn("Memory allocation for saving cpu register states failed\n");
874 return -ENOMEM;
875 }
876 return 0;
877}
878subsys_initcall(crash_notes_memory_init);
879
880#ifdef CONFIG_CRASH_HOTPLUG
881#undef pr_fmt
882#define pr_fmt(fmt) "crash hp: " fmt
883
884/*
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.
890 */
891DEFINE_MUTEX(__crash_hotplug_lock);
892#define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock)
893#define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock)
894
895/*
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.
899 */
900int crash_check_update_elfcorehdr(void)
901{
902 int rc = 0;
903
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();
909 return 0;
910 }
911 if (kexec_crash_image) {
912 if (kexec_crash_image->file_mode)
913 rc = 1;
914 else
915 rc = kexec_crash_image->update_elfcorehdr;
916 }
917 /* Release lock now that update complete */
918 kexec_unlock();
919 crash_hotplug_unlock();
920
921 return rc;
922}
923
924/*
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.
929 *
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).
937 */
938static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
939{
940 struct kimage *image;
941
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();
947 return;
948 }
949
950 /* Check kdump is not loaded */
951 if (!kexec_crash_image)
952 goto out;
953
954 image = kexec_crash_image;
955
956 /* Check that updating elfcorehdr is permitted */
957 if (!(image->file_mode || image->update_elfcorehdr))
958 goto out;
959
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);
963 else
964 pr_debug("hp_action %u\n", hp_action);
965
966 /*
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.
970 */
971 if (image->elfcorehdr_index < 0) {
972 unsigned long mem;
973 unsigned char *ptr;
974 unsigned int n;
975
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));
979 if (ptr) {
980 /* The segment containing elfcorehdr */
981 if (memcmp(p: ptr, ELFMAG, SELFMAG) == 0)
982 image->elfcorehdr_index = (int)n;
983 kunmap_local(ptr);
984 }
985 }
986 }
987
988 if (image->elfcorehdr_index < 0) {
989 pr_err("unable to locate elfcorehdr segment");
990 goto out;
991 }
992
993 /* Needed in order for the segments to be updated */
994 arch_kexec_unprotect_crashkres();
995
996 /* Differentiate between normal load and hotplug update */
997 image->hp_action = hp_action;
998
999 /* Now invoke arch-specific update handler */
1000 arch_crash_handle_hotplug_event(image);
1001
1002 /* No longer handling a hotplug event */
1003 image->hp_action = KEXEC_CRASH_HP_NONE;
1004 image->elfcorehdr_updated = true;
1005
1006 /* Change back to read-only */
1007 arch_kexec_protect_crashkres();
1008
1009 /* Errors in the callback is not a reason to rollback state */
1010out:
1011 /* Release lock now that update complete */
1012 kexec_unlock();
1013 crash_hotplug_unlock();
1014}
1015
1016static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
1017{
1018 switch (val) {
1019 case MEM_ONLINE:
1020 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
1021 KEXEC_CRASH_HP_INVALID_CPU);
1022 break;
1023
1024 case MEM_OFFLINE:
1025 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
1026 KEXEC_CRASH_HP_INVALID_CPU);
1027 break;
1028 }
1029 return NOTIFY_OK;
1030}
1031
1032static struct notifier_block crash_memhp_nb = {
1033 .notifier_call = crash_memhp_notifier,
1034 .priority = 0
1035};
1036
1037static int crash_cpuhp_online(unsigned int cpu)
1038{
1039 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
1040 return 0;
1041}
1042
1043static int crash_cpuhp_offline(unsigned int cpu)
1044{
1045 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
1046 return 0;
1047}
1048
1049static int __init crash_hotplug_init(void)
1050{
1051 int result = 0;
1052
1053 if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
1054 register_memory_notifier(nb: &crash_memhp_nb);
1055
1056 if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
1057 result = cpuhp_setup_state_nocalls(state: CPUHP_BP_PREPARE_DYN,
1058 name: "crash/cpuhp", startup: crash_cpuhp_online, teardown: crash_cpuhp_offline);
1059 }
1060
1061 return result;
1062}
1063
1064subsys_initcall(crash_hotplug_init);
1065#endif
1066

source code of linux/kernel/crash_core.c