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