kernel/crash_core.c

   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/crash_core.h>
   9 #include <linux/init.h>
  10 #include <linux/utsname.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/sizes.h>
  13 #include <linux/kexec.h>
  14 #include <linux/memory.h>
  15 #include <linux/cpuhotplug.h>
  16
  17 #include <asm/page.h>
  18 #include <asm/sections.h>
  19
  20 #include <crypto/sha1.h>
  21
  22 #include "kallsyms_internal.h"
  23 #include "kexec_internal.h"
  24
  25 /* Per cpu memory for storing cpu states in case of system crash. */
  26 note_buf_t __percpu *crash_notes;
  27
  28 /* vmcoreinfo stuff */
  29 unsigned char *vmcoreinfo_data;
  30 size_t vmcoreinfo_size;
  31 u32 *vmcoreinfo_note;
  32
  33 /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
  34 static unsigned char *vmcoreinfo_data_safecopy;
  35
  36 /*
  37  * parsing the "crashkernel" commandline
  38  *
  39  * this code is intended to be called from architecture specific code
  40  */
  41
  42
  43 /*
  44  * This function parses command lines in the format
  45  *
  46  *   crashkernel=ramsize-range:size[,...][@offset]
  47  *
  48  * The function returns 0 on success and -EINVAL on failure.
  49  */
  50 static int __init parse_crashkernel_mem(char *cmdline,
  51                                         unsigned long long system_ram,
  52                                         unsigned long long *crash_size,
  53                                         unsigned long long *crash_base)
  54 {
  55         char *cur = cmdline, *tmp;
  56         unsigned long long total_mem = system_ram;
  57
  58         /*
  59          * Firmware sometimes reserves some memory regions for its own use,
  60          * so the system memory size is less than the actual physical memory
  61          * size. Work around this by rounding up the total size to 128M,
  62          * which is enough for most test cases.
  63          */
  64         total_mem = roundup(total_mem, SZ_128M);
  65
  66         /* for each entry of the comma-separated list */
  67         do {
  68                 unsigned long long start, end = ULLONG_MAX, size;
  69
  70                 /* get the start of the range */
  71                 start = memparse(cur, &tmp);
  72                 if (cur == tmp) {
  73                         pr_warn("crashkernel: Memory value expected\n");
  74                         return -EINVAL;
  75                 }
  76                 cur = tmp;
  77                 if (*cur != '-') {
  78                         pr_warn("crashkernel: '-' expected\n");
  79                         return -EINVAL;
  80                 }
  81                 cur++;
  82
  83                 /* if no ':' is here, than we read the end */
  84                 if (*cur != ':') {
  85                         end = memparse(cur, &tmp);
  86                         if (cur == tmp) {
  87                                 pr_warn("crashkernel: Memory value expected\n");
  88                                 return -EINVAL;
  89                         }
  90                         cur = tmp;
  91                         if (end <= start) {
  92                                 pr_warn("crashkernel: end <= start\n");
  93                                 return -EINVAL;
  94                         }
  95                 }
  96
  97                 if (*cur != ':') {
  98                         pr_warn("crashkernel: ':' expected\n");
  99                         return -EINVAL;
 100                 }
 101                 cur++;
 102
 103                 size = memparse(cur, &tmp);
 104                 if (cur == tmp) {
 105                         pr_warn("Memory value expected\n");
 106                         return -EINVAL;
 107                 }
 108                 cur = tmp;
 109                 if (size >= total_mem) {
 110                         pr_warn("crashkernel: invalid size\n");
 111                         return -EINVAL;
 112                 }
 113
 114                 /* match ? */
 115                 if (total_mem >= start && total_mem < end) {
 116                         *crash_size = size;
 117                         break;
 118                 }
 119         } while (*cur++ == ',');
 120
 121         if (*crash_size > 0) {
 122                 while (*cur && *cur != ' ' && *cur != '@')
 123                         cur++;
 124                 if (*cur == '@') {
 125                         cur++;
 126                         *crash_base = memparse(cur, &tmp);
 127                         if (cur == tmp) {
 128                                 pr_warn("Memory value expected after '@'\n");
 129                                 return -EINVAL;
 130                         }
 131                 }
 132         } else
 133                 pr_info("crashkernel size resulted in zero bytes\n");
 134
 135         return 0;
 136 }
 137
 138 /*
 139  * That function parses "simple" (old) crashkernel command lines like
 140  *
 141  *      crashkernel=size[@offset]
 142  *
 143  * It returns 0 on success and -EINVAL on failure.
 144  */
 145 static int __init parse_crashkernel_simple(char *cmdline,
 146                                            unsigned long long *crash_size,
 147                                            unsigned long long *crash_base)
 148 {
 149         char *cur = cmdline;
 150
 151         *crash_size = memparse(cmdline, &cur);
 152         if (cmdline == cur) {
 153                 pr_warn("crashkernel: memory value expected\n");
 154                 return -EINVAL;
 155         }
 156
 157         if (*cur == '@')
 158                 *crash_base = memparse(cur+1, &cur);
 159         else if (*cur != ' ' && *cur != '\0') {
 160                 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 161                 return -EINVAL;
 162         }
 163
 164         return 0;
 165 }
 166
 167 #define SUFFIX_HIGH 0
 168 #define SUFFIX_LOW  1
 169 #define SUFFIX_NULL 2
 170 static __initdata char *suffix_tbl[] = {
 171         [SUFFIX_HIGH] = ",high",
 172         [SUFFIX_LOW]  = ",low",
 173         [SUFFIX_NULL] = NULL,
 174 };
 175
 176 /*
 177  * That function parses "suffix"  crashkernel command lines like
 178  *
 179  *      crashkernel=size,[high|low]
 180  *
 181  * It returns 0 on success and -EINVAL on failure.
 182  */
 183 static int __init parse_crashkernel_suffix(char *cmdline,
 184                                            unsigned long long   *crash_size,
 185                                            const char *suffix)
 186 {
 187         char *cur = cmdline;
 188
 189         *crash_size = memparse(cmdline, &cur);
 190         if (cmdline == cur) {
 191                 pr_warn("crashkernel: memory value expected\n");
 192                 return -EINVAL;
 193         }
 194
 195         /* check with suffix */
 196         if (strncmp(cur, suffix, strlen(suffix))) {
 197                 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 198                 return -EINVAL;
 199         }
 200         cur += strlen(suffix);
 201         if (*cur != ' ' && *cur != '\0') {
 202                 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 203                 return -EINVAL;
 204         }
 205
 206         return 0;
 207 }
 208
 209 static __init char *get_last_crashkernel(char *cmdline,
 210                              const char *name,
 211                              const char *suffix)
 212 {
 213         char *p = cmdline, *ck_cmdline = NULL;
 214
 215         /* find crashkernel and use the last one if there are more */
 216         p = strstr(p, name);
 217         while (p) {
 218                 char *end_p = strchr(p, ' ');
 219                 char *q;
 220
 221                 if (!end_p)
 222                         end_p = p + strlen(p);
 223
 224                 if (!suffix) {
 225                         int i;
 226
 227                         /* skip the one with any known suffix */
 228                         for (i = 0; suffix_tbl[i]; i++) {
 229                                 q = end_p - strlen(suffix_tbl[i]);
 230                                 if (!strncmp(q, suffix_tbl[i],
 231                                              strlen(suffix_tbl[i])))
 232                                         goto next;
 233                         }
 234                         ck_cmdline = p;
 235                 } else {
 236                         q = end_p - strlen(suffix);
 237                         if (!strncmp(q, suffix, strlen(suffix)))
 238                                 ck_cmdline = p;
 239                 }
 240 next:
 241                 p = strstr(p+1, name);
 242         }
 243
 244         return ck_cmdline;
 245 }
 246
 247 static int __init __parse_crashkernel(char *cmdline,
 248                              unsigned long long system_ram,
 249                              unsigned long long *crash_size,
 250                              unsigned long long *crash_base,
 251                              const char *name,
 252                              const char *suffix)
 253 {
 254         char    *first_colon, *first_space;
 255         char    *ck_cmdline;
 256
 257         BUG_ON(!crash_size || !crash_base);
 258         *crash_size = 0;
 259         *crash_base = 0;
 260
 261         ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
 262         if (!ck_cmdline)
 263                 return -ENOENT;
 264
 265         ck_cmdline += strlen(name);
 266
 267         if (suffix)
 268                 return parse_crashkernel_suffix(ck_cmdline, crash_size,
 269                                 suffix);
 270         /*
 271          * if the commandline contains a ':', then that's the extended
 272          * syntax -- if not, it must be the classic syntax
 273          */
 274         first_colon = strchr(ck_cmdline, ':');
 275         first_space = strchr(ck_cmdline, ' ');
 276         if (first_colon && (!first_space || first_colon < first_space))
 277                 return parse_crashkernel_mem(ck_cmdline, system_ram,
 278                                 crash_size, crash_base);
 279
 280         return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
 281 }
 282
 283 /*
 284  * That function is the entry point for command line parsing and should be
 285  * called from the arch-specific code.
 286  */
 287 int __init parse_crashkernel(char *cmdline,
 288                              unsigned long long system_ram,
 289                              unsigned long long *crash_size,
 290                              unsigned long long *crash_base)
 291 {
 292         return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
 293                                         "crashkernel=", NULL);
 294 }
 295
 296 int __init parse_crashkernel_high(char *cmdline,
 297                              unsigned long long system_ram,
 298                              unsigned long long *crash_size,
 299                              unsigned long long *crash_base)
 300 {
 301         return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
 302                                 "crashkernel=", suffix_tbl[SUFFIX_HIGH]);
 303 }
 304
 305 int __init parse_crashkernel_low(char *cmdline,
 306                              unsigned long long system_ram,
 307                              unsigned long long *crash_size,
 308                              unsigned long long *crash_base)
 309 {
 310         return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
 311                                 "crashkernel=", suffix_tbl[SUFFIX_LOW]);
 312 }
 313
 314 /*
 315  * Add a dummy early_param handler to mark crashkernel= as a known command line
 316  * parameter and suppress incorrect warnings in init/main.c.
 317  */
 318 static int __init parse_crashkernel_dummy(char *arg)
 319 {
 320         return 0;
 321 }
 322 early_param("crashkernel", parse_crashkernel_dummy);
 323
 324 int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
 325                           void **addr, unsigned long *sz)
 326 {
 327         Elf64_Ehdr *ehdr;
 328         Elf64_Phdr *phdr;
 329         unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
 330         unsigned char *buf;
 331         unsigned int cpu, i;
 332         unsigned long long notes_addr;
 333         unsigned long mstart, mend;
 334
 335         /* extra phdr for vmcoreinfo ELF note */
 336         nr_phdr = nr_cpus + 1;
 337         nr_phdr += mem->nr_ranges;
 338
 339         /*
 340          * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
 341          * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
 342          * I think this is required by tools like gdb. So same physical
 343          * memory will be mapped in two ELF headers. One will contain kernel
 344          * text virtual addresses and other will have __va(physical) addresses.
 345          */
 346
 347         nr_phdr++;
 348         elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
 349         elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
 350
 351         buf = vzalloc(elf_sz);
 352         if (!buf)
 353                 return -ENOMEM;
 354
 355         ehdr = (Elf64_Ehdr *)buf;
 356         phdr = (Elf64_Phdr *)(ehdr + 1);
 357         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 358         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 359         ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
 360         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 361         ehdr->e_ident[EI_OSABI] = ELF_OSABI;
 362         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 363         ehdr->e_type = ET_CORE;
 364         ehdr->e_machine = ELF_ARCH;
 365         ehdr->e_version = EV_CURRENT;
 366         ehdr->e_phoff = sizeof(Elf64_Ehdr);
 367         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
 368         ehdr->e_phentsize = sizeof(Elf64_Phdr);
 369
 370         /* Prepare one phdr of type PT_NOTE for each possible CPU */
 371         for_each_possible_cpu(cpu) {
 372                 phdr->p_type = PT_NOTE;
 373                 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
 374                 phdr->p_offset = phdr->p_paddr = notes_addr;
 375                 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
 376                 (ehdr->e_phnum)++;
 377                 phdr++;
 378         }
 379
 380         /* Prepare one PT_NOTE header for vmcoreinfo */
 381         phdr->p_type = PT_NOTE;
 382         phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
 383         phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
 384         (ehdr->e_phnum)++;
 385         phdr++;
 386
 387         /* Prepare PT_LOAD type program header for kernel text region */
 388         if (need_kernel_map) {
 389                 phdr->p_type = PT_LOAD;
 390                 phdr->p_flags = PF_R|PF_W|PF_X;
 391                 phdr->p_vaddr = (unsigned long) _text;
 392                 phdr->p_filesz = phdr->p_memsz = _end - _text;
 393                 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
 394                 ehdr->e_phnum++;
 395                 phdr++;
 396         }
 397
 398         /* Go through all the ranges in mem->ranges[] and prepare phdr */
 399         for (i = 0; i < mem->nr_ranges; i++) {
 400                 mstart = mem->ranges[i].start;
 401                 mend = mem->ranges[i].end;
 402
 403                 phdr->p_type = PT_LOAD;
 404                 phdr->p_flags = PF_R|PF_W|PF_X;
 405                 phdr->p_offset  = mstart;
 406
 407                 phdr->p_paddr = mstart;
 408                 phdr->p_vaddr = (unsigned long) __va(mstart);
 409                 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
 410                 phdr->p_align = 0;
 411                 ehdr->e_phnum++;
 412                 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",
 413                         phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
 414                         ehdr->e_phnum, phdr->p_offset);
 415                 phdr++;
 416         }
 417
 418         *addr = buf;
 419         *sz = elf_sz;
 420         return 0;
 421 }
 422
 423 int crash_exclude_mem_range(struct crash_mem *mem,
 424                             unsigned long long mstart, unsigned long long mend)
 425 {
 426         int i, j;
 427         unsigned long long start, end, p_start, p_end;
 428         struct range temp_range = {0, 0};
 429
 430         for (i = 0; i < mem->nr_ranges; i++) {
 431                 start = mem->ranges[i].start;
 432                 end = mem->ranges[i].end;
 433                 p_start = mstart;
 434                 p_end = mend;
 435
 436                 if (mstart > end || mend < start)
 437                         continue;
 438
 439                 /* Truncate any area outside of range */
 440                 if (mstart < start)
 441                         p_start = start;
 442                 if (mend > end)
 443                         p_end = end;
 444
 445                 /* Found completely overlapping range */
 446                 if (p_start == start && p_end == end) {
 447                         mem->ranges[i].start = 0;
 448                         mem->ranges[i].end = 0;
 449                         if (i < mem->nr_ranges - 1) {
 450                                 /* Shift rest of the ranges to left */
 451                                 for (j = i; j < mem->nr_ranges - 1; j++) {
 452                                         mem->ranges[j].start =
 453                                                 mem->ranges[j+1].start;
 454                                         mem->ranges[j].end =
 455                                                         mem->ranges[j+1].end;
 456                                 }
 457
 458                                 /*
 459                                  * Continue to check if there are another overlapping ranges
 460                                  * from the current position because of shifting the above
 461                                  * mem ranges.
 462                                  */
 463                                 i--;
 464                                 mem->nr_ranges--;
 465                                 continue;
 466                         }
 467                         mem->nr_ranges--;
 468                         return 0;
 469                 }
 470
 471                 if (p_start > start && p_end < end) {
 472                         /* Split original range */
 473                         mem->ranges[i].end = p_start - 1;
 474                         temp_range.start = p_end + 1;
 475                         temp_range.end = end;
 476                 } else if (p_start != start)
 477                         mem->ranges[i].end = p_start - 1;
 478                 else
 479                         mem->ranges[i].start = p_end + 1;
 480                 break;
 481         }
 482
 483         /* If a split happened, add the split to array */
 484         if (!temp_range.end)
 485                 return 0;
 486
 487         /* Split happened */
 488         if (i == mem->max_nr_ranges - 1)
 489                 return -ENOMEM;
 490
 491         /* Location where new range should go */
 492         j = i + 1;
 493         if (j < mem->nr_ranges) {
 494                 /* Move over all ranges one slot towards the end */
 495                 for (i = mem->nr_ranges - 1; i >= j; i--)
 496                         mem->ranges[i + 1] = mem->ranges[i];
 497         }
 498
 499         mem->ranges[j].start = temp_range.start;
 500         mem->ranges[j].end = temp_range.end;
 501         mem->nr_ranges++;
 502         return 0;
 503 }
 504
 505 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 506                           void *data, size_t data_len)
 507 {
 508         struct elf_note *note = (struct elf_note *)buf;
 509
 510         note->n_namesz = strlen(name) + 1;
 511         note->n_descsz = data_len;
 512         note->n_type   = type;
 513         buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
 514         memcpy(buf, name, note->n_namesz);
 515         buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
 516         memcpy(buf, data, data_len);
 517         buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
 518
 519         return buf;
 520 }
 521
 522 void final_note(Elf_Word *buf)
 523 {
 524         memset(buf, 0, sizeof(struct elf_note));
 525 }
 526
 527 static void update_vmcoreinfo_note(void)
 528 {
 529         u32 *buf = vmcoreinfo_note;
 530
 531         if (!vmcoreinfo_size)
 532                 return;
 533         buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
 534                               vmcoreinfo_size);
 535         final_note(buf);
 536 }
 537
 538 void crash_update_vmcoreinfo_safecopy(void *ptr)
 539 {
 540         if (ptr)
 541                 memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
 542
 543         vmcoreinfo_data_safecopy = ptr;
 544 }
 545
 546 void crash_save_vmcoreinfo(void)
 547 {
 548         if (!vmcoreinfo_note)
 549                 return;
 550
 551         /* Use the safe copy to generate vmcoreinfo note if have */
 552         if (vmcoreinfo_data_safecopy)
 553                 vmcoreinfo_data = vmcoreinfo_data_safecopy;
 554
 555         vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
 556         update_vmcoreinfo_note();
 557 }
 558
 559 void vmcoreinfo_append_str(const char *fmt, ...)
 560 {
 561         va_list args;
 562         char buf[0x50];
 563         size_t r;
 564
 565         va_start(args, fmt);
 566         r = vscnprintf(buf, sizeof(buf), fmt, args);
 567         va_end(args);
 568
 569         r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);
 570
 571         memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
 572
 573         vmcoreinfo_size += r;
 574
 575         WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES,
 576                   "vmcoreinfo data exceeds allocated size, truncating");
 577 }
 578
 579 /*
 580  * provide an empty default implementation here -- architecture
 581  * code may override this
 582  */
 583 void __weak arch_crash_save_vmcoreinfo(void)
 584 {}
 585
 586 phys_addr_t __weak paddr_vmcoreinfo_note(void)
 587 {
 588         return __pa(vmcoreinfo_note);
 589 }
 590 EXPORT_SYMBOL(paddr_vmcoreinfo_note);
 591
 592 static int __init crash_save_vmcoreinfo_init(void)
 593 {
 594         vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
 595         if (!vmcoreinfo_data) {
 596                 pr_warn("Memory allocation for vmcoreinfo_data failed\n");
 597                 return -ENOMEM;
 598         }
 599
 600         vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
 601                                                 GFP_KERNEL | __GFP_ZERO);
 602         if (!vmcoreinfo_note) {
 603                 free_page((unsigned long)vmcoreinfo_data);
 604                 vmcoreinfo_data = NULL;
 605                 pr_warn("Memory allocation for vmcoreinfo_note failed\n");
 606                 return -ENOMEM;
 607         }
 608
 609         VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
 610         VMCOREINFO_BUILD_ID();
 611         VMCOREINFO_PAGESIZE(PAGE_SIZE);
 612
 613         VMCOREINFO_SYMBOL(init_uts_ns);
 614         VMCOREINFO_OFFSET(uts_namespace, name);
 615         VMCOREINFO_SYMBOL(node_online_map);
 616 #ifdef CONFIG_MMU
 617         VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
 618 #endif
 619         VMCOREINFO_SYMBOL(_stext);
 620         VMCOREINFO_SYMBOL(vmap_area_list);
 621
 622 #ifndef CONFIG_NUMA
 623         VMCOREINFO_SYMBOL(mem_map);
 624         VMCOREINFO_SYMBOL(contig_page_data);
 625 #endif
 626 #ifdef CONFIG_SPARSEMEM
 627         VMCOREINFO_SYMBOL_ARRAY(mem_section);
 628         VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
 629         VMCOREINFO_STRUCT_SIZE(mem_section);
 630         VMCOREINFO_OFFSET(mem_section, section_mem_map);
 631         VMCOREINFO_NUMBER(SECTION_SIZE_BITS);
 632         VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
 633 #endif
 634         VMCOREINFO_STRUCT_SIZE(page);
 635         VMCOREINFO_STRUCT_SIZE(pglist_data);
 636         VMCOREINFO_STRUCT_SIZE(zone);
 637         VMCOREINFO_STRUCT_SIZE(free_area);
 638         VMCOREINFO_STRUCT_SIZE(list_head);
 639         VMCOREINFO_SIZE(nodemask_t);
 640         VMCOREINFO_OFFSET(page, flags);
 641         VMCOREINFO_OFFSET(page, _refcount);
 642         VMCOREINFO_OFFSET(page, mapping);
 643         VMCOREINFO_OFFSET(page, lru);
 644         VMCOREINFO_OFFSET(page, _mapcount);
 645         VMCOREINFO_OFFSET(page, private);
 646         VMCOREINFO_OFFSET(page, compound_head);
 647         VMCOREINFO_OFFSET(pglist_data, node_zones);
 648         VMCOREINFO_OFFSET(pglist_data, nr_zones);
 649 #ifdef CONFIG_FLATMEM
 650         VMCOREINFO_OFFSET(pglist_data, node_mem_map);
 651 #endif
 652         VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
 653         VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
 654         VMCOREINFO_OFFSET(pglist_data, node_id);
 655         VMCOREINFO_OFFSET(zone, free_area);
 656         VMCOREINFO_OFFSET(zone, vm_stat);
 657         VMCOREINFO_OFFSET(zone, spanned_pages);
 658         VMCOREINFO_OFFSET(free_area, free_list);
 659         VMCOREINFO_OFFSET(list_head, next);
 660         VMCOREINFO_OFFSET(list_head, prev);
 661         VMCOREINFO_OFFSET(vmap_area, va_start);
 662         VMCOREINFO_OFFSET(vmap_area, list);
 663         VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER + 1);
 664         log_buf_vmcoreinfo_setup();
 665         VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
 666         VMCOREINFO_NUMBER(NR_FREE_PAGES);
 667         VMCOREINFO_NUMBER(PG_lru);
 668         VMCOREINFO_NUMBER(PG_private);
 669         VMCOREINFO_NUMBER(PG_swapcache);
 670         VMCOREINFO_NUMBER(PG_swapbacked);
 671         VMCOREINFO_NUMBER(PG_slab);
 672 #ifdef CONFIG_MEMORY_FAILURE
 673         VMCOREINFO_NUMBER(PG_hwpoison);
 674 #endif
 675         VMCOREINFO_NUMBER(PG_head_mask);
 676 #define PAGE_BUDDY_MAPCOUNT_VALUE       (~PG_buddy)
 677         VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
 678 #ifdef CONFIG_HUGETLB_PAGE
 679         VMCOREINFO_NUMBER(PG_hugetlb);
 680 #define PAGE_OFFLINE_MAPCOUNT_VALUE     (~PG_offline)
 681         VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
 682 #endif
 683
 684 #ifdef CONFIG_KALLSYMS
 685         VMCOREINFO_SYMBOL(kallsyms_names);
 686         VMCOREINFO_SYMBOL(kallsyms_num_syms);
 687         VMCOREINFO_SYMBOL(kallsyms_token_table);
 688         VMCOREINFO_SYMBOL(kallsyms_token_index);
 689 #ifdef CONFIG_KALLSYMS_BASE_RELATIVE
 690         VMCOREINFO_SYMBOL(kallsyms_offsets);
 691         VMCOREINFO_SYMBOL(kallsyms_relative_base);
 692 #else
 693         VMCOREINFO_SYMBOL(kallsyms_addresses);
 694 #endif /* CONFIG_KALLSYMS_BASE_RELATIVE */
 695 #endif /* CONFIG_KALLSYMS */
 696
 697         arch_crash_save_vmcoreinfo();
 698         update_vmcoreinfo_note();
 699
 700         return 0;
 701 }
 702
 703 subsys_initcall(crash_save_vmcoreinfo_init);
 704
 705 static int __init crash_notes_memory_init(void)
 706 {
 707         /* Allocate memory for saving cpu registers. */
 708         size_t size, align;
 709
 710         /*
 711          * crash_notes could be allocated across 2 vmalloc pages when percpu
 712          * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
 713          * pages are also on 2 continuous physical pages. In this case the
 714          * 2nd part of crash_notes in 2nd page could be lost since only the
 715          * starting address and size of crash_notes are exported through sysfs.
 716          * Here round up the size of crash_notes to the nearest power of two
 717          * and pass it to __alloc_percpu as align value. This can make sure
 718          * crash_notes is allocated inside one physical page.
 719          */
 720         size = sizeof(note_buf_t);
 721         align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
 722
 723         /*
 724          * Break compile if size is bigger than PAGE_SIZE since crash_notes
 725          * definitely will be in 2 pages with that.
 726          */
 727         BUILD_BUG_ON(size > PAGE_SIZE);
 728
 729         crash_notes = __alloc_percpu(size, align);
 730         if (!crash_notes) {
 731                 pr_warn("Memory allocation for saving cpu register states failed\n");
 732                 return -ENOMEM;
 733         }
 734         return 0;
 735 }
 736 subsys_initcall(crash_notes_memory_init);
 737
 738 #ifdef CONFIG_CRASH_HOTPLUG
 739 #undef pr_fmt
 740 #define pr_fmt(fmt) "crash hp: " fmt
 741
 742 /*
 743  * This routine utilized when the crash_hotplug sysfs node is read.
 744  * It reflects the kernel's ability/permission to update the crash
 745  * elfcorehdr directly.
 746  */
 747 int crash_check_update_elfcorehdr(void)
 748 {
 749         int rc = 0;
 750
 751         /* Obtain lock while reading crash information */
 752         if (!kexec_trylock()) {
 753                 pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
 754                 return 0;
 755         }
 756         if (kexec_crash_image) {
 757                 if (kexec_crash_image->file_mode)
 758                         rc = 1;
 759                 else
 760                         rc = kexec_crash_image->update_elfcorehdr;
 761         }
 762         /* Release lock now that update complete */
 763         kexec_unlock();
 764
 765         return rc;
 766 }
 767
 768 /*
 769  * To accurately reflect hot un/plug changes of cpu and memory resources
 770  * (including onling and offlining of those resources), the elfcorehdr
 771  * (which is passed to the crash kernel via the elfcorehdr= parameter)
 772  * must be updated with the new list of CPUs and memories.
 773  *
 774  * In order to make changes to elfcorehdr, two conditions are needed:
 775  * First, the segment containing the elfcorehdr must be large enough
 776  * to permit a growing number of resources; the elfcorehdr memory size
 777  * is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES.
 778  * Second, purgatory must explicitly exclude the elfcorehdr from the
 779  * list of segments it checks (since the elfcorehdr changes and thus
 780  * would require an update to purgatory itself to update the digest).
 781  */
 782 static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
 783 {
 784         struct kimage *image;
 785
 786         /* Obtain lock while changing crash information */
 787         if (!kexec_trylock()) {
 788                 pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
 789                 return;
 790         }
 791
 792         /* Check kdump is not loaded */
 793         if (!kexec_crash_image)
 794                 goto out;
 795
 796         image = kexec_crash_image;
 797
 798         /* Check that updating elfcorehdr is permitted */
 799         if (!(image->file_mode || image->update_elfcorehdr))
 800                 goto out;
 801
 802         if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
 803                 hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
 804                 pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
 805         else
 806                 pr_debug("hp_action %u\n", hp_action);
 807
 808         /*
 809          * The elfcorehdr_index is set to -1 when the struct kimage
 810          * is allocated. Find the segment containing the elfcorehdr,
 811          * if not already found.
 812          */
 813         if (image->elfcorehdr_index < 0) {
 814                 unsigned long mem;
 815                 unsigned char *ptr;
 816                 unsigned int n;
 817
 818                 for (n = 0; n < image->nr_segments; n++) {
 819                         mem = image->segment[n].mem;
 820                         ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
 821                         if (ptr) {
 822                                 /* The segment containing elfcorehdr */
 823                                 if (memcmp(ptr, ELFMAG, SELFMAG) == 0)
 824                                         image->elfcorehdr_index = (int)n;
 825                                 kunmap_local(ptr);
 826                         }
 827                 }
 828         }
 829
 830         if (image->elfcorehdr_index < 0) {
 831                 pr_err("unable to locate elfcorehdr segment");
 832                 goto out;
 833         }
 834
 835         /* Needed in order for the segments to be updated */
 836         arch_kexec_unprotect_crashkres();
 837
 838         /* Differentiate between normal load and hotplug update */
 839         image->hp_action = hp_action;
 840
 841         /* Now invoke arch-specific update handler */
 842         arch_crash_handle_hotplug_event(image);
 843
 844         /* No longer handling a hotplug event */
 845         image->hp_action = KEXEC_CRASH_HP_NONE;
 846         image->elfcorehdr_updated = true;
 847
 848         /* Change back to read-only */
 849         arch_kexec_protect_crashkres();
 850
 851         /* Errors in the callback is not a reason to rollback state */
 852 out:
 853         /* Release lock now that update complete */
 854         kexec_unlock();
 855 }
 856
 857 static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
 858 {
 859         switch (val) {
 860         case MEM_ONLINE:
 861                 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
 862                         KEXEC_CRASH_HP_INVALID_CPU);
 863                 break;
 864
 865         case MEM_OFFLINE:
 866                 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
 867                         KEXEC_CRASH_HP_INVALID_CPU);
 868                 break;
 869         }
 870         return NOTIFY_OK;
 871 }
 872
 873 static struct notifier_block crash_memhp_nb = {
 874         .notifier_call = crash_memhp_notifier,
 875         .priority = 0
 876 };
 877
 878 static int crash_cpuhp_online(unsigned int cpu)
 879 {
 880         crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
 881         return 0;
 882 }
 883
 884 static int crash_cpuhp_offline(unsigned int cpu)
 885 {
 886         crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
 887         return 0;
 888 }
 889
 890 static int __init crash_hotplug_init(void)
 891 {
 892         int result = 0;
 893
 894         if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
 895                 register_memory_notifier(&crash_memhp_nb);
 896
 897         if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
 898                 result = cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN,
 899                         "crash/cpuhp", crash_cpuhp_online, crash_cpuhp_offline);
 900         }
 901
 902         return result;
 903 }
 904
 905 subsys_initcall(crash_hotplug_init);
 906 #endif