kernel/crash_reserve.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/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/kmemleak.h>
  17
  18 #include <asm/page.h>
  19 #include <asm/sections.h>
  20
  21 #include <crypto/sha1.h>
  22
  23 #include "kallsyms_internal.h"
  24 #include "kexec_internal.h"
  25
  26 /* Location of the reserved area for the crash kernel */
  27 struct resource crashk_res = {
  28         .name  = "Crash kernel",
  29         .start = 0,
  30         .end   = 0,
  31         .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
  32         .desc  = IORES_DESC_CRASH_KERNEL
  33 };
  34 struct resource crashk_low_res = {
  35         .name  = "Crash kernel",
  36         .start = 0,
  37         .end   = 0,
  38         .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
  39         .desc  = IORES_DESC_CRASH_KERNEL
  40 };
  41
  42 /*
  43  * parsing the "crashkernel" commandline
  44  *
  45  * this code is intended to be called from architecture specific code
  46  */
  47
  48
  49 /*
  50  * This function parses command lines in the format
  51  *
  52  *   crashkernel=ramsize-range:size[,...][@offset]
  53  *
  54  * The function returns 0 on success and -EINVAL on failure.
  55  */
  56 static int __init parse_crashkernel_mem(char *cmdline,
  57                                         unsigned long long system_ram,
  58                                         unsigned long long *crash_size,
  59                                         unsigned long long *crash_base)
  60 {
  61         char *cur = cmdline, *tmp;
  62         unsigned long long total_mem = system_ram;
  63
  64         /*
  65          * Firmware sometimes reserves some memory regions for its own use,
  66          * so the system memory size is less than the actual physical memory
  67          * size. Work around this by rounding up the total size to 128M,
  68          * which is enough for most test cases.
  69          */
  70         total_mem = roundup(total_mem, SZ_128M);
  71
  72         /* for each entry of the comma-separated list */
  73         do {
  74                 unsigned long long start, end = ULLONG_MAX, size;
  75
  76                 /* get the start of the range */
  77                 start = memparse(cur, &tmp);
  78                 if (cur == tmp) {
  79                         pr_warn("crashkernel: Memory value expected\n");
  80                         return -EINVAL;
  81                 }
  82                 cur = tmp;
  83                 if (*cur != '-') {
  84                         pr_warn("crashkernel: '-' expected\n");
  85                         return -EINVAL;
  86                 }
  87                 cur++;
  88
  89                 /* if no ':' is here, than we read the end */
  90                 if (*cur != ':') {
  91                         end = memparse(cur, &tmp);
  92                         if (cur == tmp) {
  93                                 pr_warn("crashkernel: Memory value expected\n");
  94                                 return -EINVAL;
  95                         }
  96                         cur = tmp;
  97                         if (end <= start) {
  98                                 pr_warn("crashkernel: end <= start\n");
  99                                 return -EINVAL;
 100                         }
 101                 }
 102
 103                 if (*cur != ':') {
 104                         pr_warn("crashkernel: ':' expected\n");
 105                         return -EINVAL;
 106                 }
 107                 cur++;
 108
 109                 size = memparse(cur, &tmp);
 110                 if (cur == tmp) {
 111                         pr_warn("crashkernel: Memory value expected\n");
 112                         return -EINVAL;
 113                 }
 114                 cur = tmp;
 115                 if (size >= total_mem) {
 116                         pr_warn("crashkernel: invalid size\n");
 117                         return -EINVAL;
 118                 }
 119
 120                 /* match ? */
 121                 if (total_mem >= start && total_mem < end) {
 122                         *crash_size = size;
 123                         break;
 124                 }
 125         } while (*cur++ == ',');
 126
 127         if (*crash_size > 0) {
 128                 while (*cur && *cur != ' ' && *cur != '@')
 129                         cur++;
 130                 if (*cur == '@') {
 131                         cur++;
 132                         *crash_base = memparse(cur, &tmp);
 133                         if (cur == tmp) {
 134                                 pr_warn("crahskernel: Memory value expected after '@'\n");
 135                                 return -EINVAL;
 136                         }
 137                 }
 138         } else
 139                 pr_info("crashkernel size resulted in zero bytes\n");
 140
 141         return 0;
 142 }
 143
 144 /*
 145  * That function parses "simple" (old) crashkernel command lines like
 146  *
 147  *      crashkernel=size[@offset]
 148  *
 149  * It returns 0 on success and -EINVAL on failure.
 150  */
 151 static int __init parse_crashkernel_simple(char *cmdline,
 152                                            unsigned long long *crash_size,
 153                                            unsigned long long *crash_base)
 154 {
 155         char *cur = cmdline;
 156
 157         *crash_size = memparse(cmdline, &cur);
 158         if (cmdline == cur) {
 159                 pr_warn("crashkernel: memory value expected\n");
 160                 return -EINVAL;
 161         }
 162
 163         if (*cur == '@')
 164                 *crash_base = memparse(cur+1, &cur);
 165         else if (*cur != ' ' && *cur != '\0') {
 166                 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 167                 return -EINVAL;
 168         }
 169
 170         return 0;
 171 }
 172
 173 #define SUFFIX_HIGH 0
 174 #define SUFFIX_LOW  1
 175 #define SUFFIX_NULL 2
 176 static __initdata char *suffix_tbl[] = {
 177         [SUFFIX_HIGH] = ",high",
 178         [SUFFIX_LOW]  = ",low",
 179         [SUFFIX_NULL] = NULL,
 180 };
 181
 182 /*
 183  * That function parses "suffix"  crashkernel command lines like
 184  *
 185  *      crashkernel=size,[high|low]
 186  *
 187  * It returns 0 on success and -EINVAL on failure.
 188  */
 189 static int __init parse_crashkernel_suffix(char *cmdline,
 190                                            unsigned long long *crash_size,
 191                                            const char *suffix)
 192 {
 193         char *cur = cmdline;
 194
 195         *crash_size = memparse(cmdline, &cur);
 196         if (cmdline == cur) {
 197                 pr_warn("crashkernel: memory value expected\n");
 198                 return -EINVAL;
 199         }
 200
 201         /* check with suffix */
 202         if (strncmp(cur, suffix, strlen(suffix))) {
 203                 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 204                 return -EINVAL;
 205         }
 206         cur += strlen(suffix);
 207         if (*cur != ' ' && *cur != '\0') {
 208                 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 209                 return -EINVAL;
 210         }
 211
 212         return 0;
 213 }
 214
 215 static __init char *get_last_crashkernel(char *cmdline,
 216                              const char *name,
 217                              const char *suffix)
 218 {
 219         char *p = cmdline, *ck_cmdline = NULL;
 220
 221         /* find crashkernel and use the last one if there are more */
 222         p = strstr(p, name);
 223         while (p) {
 224                 char *end_p = strchr(p, ' ');
 225                 char *q;
 226
 227                 if (!end_p)
 228                         end_p = p + strlen(p);
 229
 230                 if (!suffix) {
 231                         int i;
 232
 233                         /* skip the one with any known suffix */
 234                         for (i = 0; suffix_tbl[i]; i++) {
 235                                 q = end_p - strlen(suffix_tbl[i]);
 236                                 if (!strncmp(q, suffix_tbl[i],
 237                                              strlen(suffix_tbl[i])))
 238                                         goto next;
 239                         }
 240                         ck_cmdline = p;
 241                 } else {
 242                         q = end_p - strlen(suffix);
 243                         if (!strncmp(q, suffix, strlen(suffix)))
 244                                 ck_cmdline = p;
 245                 }
 246 next:
 247                 p = strstr(p+1, name);
 248         }
 249
 250         return ck_cmdline;
 251 }
 252
 253 static int __init __parse_crashkernel(char *cmdline,
 254                              unsigned long long system_ram,
 255                              unsigned long long *crash_size,
 256                              unsigned long long *crash_base,
 257                              const char *suffix)
 258 {
 259         char *first_colon, *first_space;
 260         char *ck_cmdline;
 261         char *name = "crashkernel=";
 262
 263         BUG_ON(!crash_size || !crash_base);
 264         *crash_size = 0;
 265         *crash_base = 0;
 266
 267         ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
 268         if (!ck_cmdline)
 269                 return -ENOENT;
 270
 271         ck_cmdline += strlen(name);
 272
 273         if (suffix)
 274                 return parse_crashkernel_suffix(ck_cmdline, crash_size,
 275                                 suffix);
 276         /*
 277          * if the commandline contains a ':', then that's the extended
 278          * syntax -- if not, it must be the classic syntax
 279          */
 280         first_colon = strchr(ck_cmdline, ':');
 281         first_space = strchr(ck_cmdline, ' ');
 282         if (first_colon && (!first_space || first_colon < first_space))
 283                 return parse_crashkernel_mem(ck_cmdline, system_ram,
 284                                 crash_size, crash_base);
 285
 286         return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
 287 }
 288
 289 /*
 290  * That function is the entry point for command line parsing and should be
 291  * called from the arch-specific code.
 292  *
 293  * If crashkernel=,high|low is supported on architecture, non-NULL values
 294  * should be passed to parameters 'low_size' and 'high'.
 295  */
 296 int __init parse_crashkernel(char *cmdline,
 297                              unsigned long long system_ram,
 298                              unsigned long long *crash_size,
 299                              unsigned long long *crash_base,
 300                              unsigned long long *low_size,
 301                              bool *high)
 302 {
 303         int ret;
 304
 305         /* crashkernel=X[@offset] */
 306         ret = __parse_crashkernel(cmdline, system_ram, crash_size,
 307                                 crash_base, NULL);
 308 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
 309         /*
 310          * If non-NULL 'high' passed in and no normal crashkernel
 311          * setting detected, try parsing crashkernel=,high|low.
 312          */
 313         if (high && ret == -ENOENT) {
 314                 ret = __parse_crashkernel(cmdline, 0, crash_size,
 315                                 crash_base, suffix_tbl[SUFFIX_HIGH]);
 316                 if (ret || !*crash_size)
 317                         return -EINVAL;
 318
 319                 /*
 320                  * crashkernel=Y,low can be specified or not, but invalid value
 321                  * is not allowed.
 322                  */
 323                 ret = __parse_crashkernel(cmdline, 0, low_size,
 324                                 crash_base, suffix_tbl[SUFFIX_LOW]);
 325                 if (ret == -ENOENT) {
 326                         *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
 327                         ret = 0;
 328                 } else if (ret) {
 329                         return ret;
 330                 }
 331
 332                 *high = true;
 333         }
 334 #endif
 335         if (!*crash_size)
 336                 ret = -EINVAL;
 337
 338         if (*crash_size >= system_ram)
 339                 ret = -EINVAL;
 340
 341         return ret;
 342 }
 343
 344 /*
 345  * Add a dummy early_param handler to mark crashkernel= as a known command line
 346  * parameter and suppress incorrect warnings in init/main.c.
 347  */
 348 static int __init parse_crashkernel_dummy(char *arg)
 349 {
 350         return 0;
 351 }
 352 early_param("crashkernel", parse_crashkernel_dummy);
 353
 354 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
 355 static int __init reserve_crashkernel_low(unsigned long long low_size)
 356 {
 357 #ifdef CONFIG_64BIT
 358         unsigned long long low_base;
 359
 360         low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
 361         if (!low_base) {
 362                 pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
 363                 return -ENOMEM;
 364         }
 365
 366         pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
 367                 low_base, low_base + low_size, low_size >> 20);
 368
 369         crashk_low_res.start = low_base;
 370         crashk_low_res.end   = low_base + low_size - 1;
 371 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
 372         insert_resource(&iomem_resource, &crashk_low_res);
 373 #endif
 374 #endif
 375         return 0;
 376 }
 377
 378 void __init reserve_crashkernel_generic(char *cmdline,
 379                              unsigned long long crash_size,
 380                              unsigned long long crash_base,
 381                              unsigned long long crash_low_size,
 382                              bool high)
 383 {
 384         unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
 385         bool fixed_base = false;
 386
 387         /* User specifies base address explicitly. */
 388         if (crash_base) {
 389                 fixed_base = true;
 390                 search_base = crash_base;
 391                 search_end = crash_base + crash_size;
 392         } else if (high) {
 393                 search_base = CRASH_ADDR_LOW_MAX;
 394                 search_end = CRASH_ADDR_HIGH_MAX;
 395         }
 396
 397 retry:
 398         crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
 399                                                search_base, search_end);
 400         if (!crash_base) {
 401                 /*
 402                  * For crashkernel=size[KMG]@offset[KMG], print out failure
 403                  * message if can't reserve the specified region.
 404                  */
 405                 if (fixed_base) {
 406                         pr_warn("crashkernel reservation failed - memory is in use.\n");
 407                         return;
 408                 }
 409
 410                 /*
 411                  * For crashkernel=size[KMG], if the first attempt was for
 412                  * low memory, fall back to high memory, the minimum required
 413                  * low memory will be reserved later.
 414                  */
 415                 if (!high && search_end == CRASH_ADDR_LOW_MAX) {
 416                         search_end = CRASH_ADDR_HIGH_MAX;
 417                         search_base = CRASH_ADDR_LOW_MAX;
 418                         crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
 419                         goto retry;
 420                 }
 421
 422                 /*
 423                  * For crashkernel=size[KMG],high, if the first attempt was
 424                  * for high memory, fall back to low memory.
 425                  */
 426                 if (high && search_end == CRASH_ADDR_HIGH_MAX) {
 427                         search_end = CRASH_ADDR_LOW_MAX;
 428                         search_base = 0;
 429                         if (search_end != CRASH_ADDR_HIGH_MAX)
 430                                 goto retry;
 431                 }
 432                 pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
 433                         crash_size);
 434                 return;
 435         }
 436
 437         if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
 438              crash_low_size && reserve_crashkernel_low(crash_low_size)) {
 439                 memblock_phys_free(crash_base, crash_size);
 440                 return;
 441         }
 442
 443         pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
 444                 crash_base, crash_base + crash_size, crash_size >> 20);
 445
 446         /*
 447          * The crashkernel memory will be removed from the kernel linear
 448          * map. Inform kmemleak so that it won't try to access it.
 449          */
 450         kmemleak_ignore_phys(crash_base);
 451         if (crashk_low_res.end)
 452                 kmemleak_ignore_phys(crashk_low_res.start);
 453
 454         crashk_res.start = crash_base;
 455         crashk_res.end = crash_base + crash_size - 1;
 456 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
 457         insert_resource(&iomem_resource, &crashk_res);
 458 #endif
 459 }
 460
 461 #ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
 462 static __init int insert_crashkernel_resources(void)
 463 {
 464         if (crashk_res.start < crashk_res.end)
 465                 insert_resource(&iomem_resource, &crashk_res);
 466
 467         if (crashk_low_res.start < crashk_low_res.end)
 468                 insert_resource(&iomem_resource, &crashk_low_res);
 469
 470         return 0;
 471 }
 472 early_initcall(insert_crashkernel_resources);
 473 #endif
 474 #endif