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 #include <linux/cma.h> 18 #include <linux/crash_reserve.h> 19 20 #include <asm/page.h> 21 #include <asm/sections.h> 22 23 #include <crypto/sha1.h> 24 25 #include "kallsyms_internal.h" 26 #include "kexec_internal.h" 27 28 /* Location of the reserved area for the crash kernel */ 29 struct resource crashk_res = { 30 .name = "Crash kernel", 31 .start = 0, 32 .end = 0, 33 .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM, 34 .desc = IORES_DESC_CRASH_KERNEL 35 }; 36 struct resource crashk_low_res = { 37 .name = "Crash kernel", 38 .start = 0, 39 .end = 0, 40 .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM, 41 .desc = IORES_DESC_CRASH_KERNEL 42 }; 43 44 /* 45 * parsing the "crashkernel" commandline 46 * 47 * this code is intended to be called from architecture specific code 48 */ 49 50 51 /* 52 * This function parses command lines in the format 53 * 54 * crashkernel=ramsize-range:size[,...][@offset] 55 * 56 * The function returns 0 on success and -EINVAL on failure. 57 */ 58 static int __init parse_crashkernel_mem(char *cmdline, 59 unsigned long long system_ram, 60 unsigned long long *crash_size, 61 unsigned long long *crash_base) 62 { 63 char *cur = cmdline, *tmp; 64 unsigned long long total_mem = system_ram; 65 66 /* 67 * Firmware sometimes reserves some memory regions for its own use, 68 * so the system memory size is less than the actual physical memory 69 * size. Work around this by rounding up the total size to 128M, 70 * which is enough for most test cases. 71 */ 72 total_mem = roundup(total_mem, SZ_128M); 73 74 /* for each entry of the comma-separated list */ 75 do { 76 unsigned long long start, end = ULLONG_MAX, size; 77 78 /* get the start of the range */ 79 start = memparse(cur, &tmp); 80 if (cur == tmp) { 81 pr_warn("crashkernel: Memory value expected\n"); 82 return -EINVAL; 83 } 84 cur = tmp; 85 if (*cur != '-') { 86 pr_warn("crashkernel: '-' expected\n"); 87 return -EINVAL; 88 } 89 cur++; 90 91 /* if no ':' is here, than we read the end */ 92 if (*cur != ':') { 93 end = memparse(cur, &tmp); 94 if (cur == tmp) { 95 pr_warn("crashkernel: Memory value expected\n"); 96 return -EINVAL; 97 } 98 cur = tmp; 99 if (end <= start) { 100 pr_warn("crashkernel: end <= start\n"); 101 return -EINVAL; 102 } 103 } 104 105 if (*cur != ':') { 106 pr_warn("crashkernel: ':' expected\n"); 107 return -EINVAL; 108 } 109 cur++; 110 111 size = memparse(cur, &tmp); 112 if (cur == tmp) { 113 pr_warn("crashkernel: Memory value expected\n"); 114 return -EINVAL; 115 } 116 cur = tmp; 117 if (size >= total_mem) { 118 pr_warn("crashkernel: invalid size\n"); 119 return -EINVAL; 120 } 121 122 /* match ? */ 123 if (total_mem >= start && total_mem < end) { 124 *crash_size = size; 125 break; 126 } 127 } while (*cur++ == ','); 128 129 if (*crash_size > 0) { 130 while (*cur && *cur != ' ' && *cur != '@') 131 cur++; 132 if (*cur == '@') { 133 cur++; 134 *crash_base = memparse(cur, &tmp); 135 if (cur == tmp) { 136 pr_warn("crashkernel: Memory value expected after '@'\n"); 137 return -EINVAL; 138 } 139 } 140 } else 141 pr_info("crashkernel size resulted in zero bytes\n"); 142 143 return 0; 144 } 145 146 /* 147 * That function parses "simple" (old) crashkernel command lines like 148 * 149 * crashkernel=size[@offset] 150 * 151 * It returns 0 on success and -EINVAL on failure. 152 */ 153 static int __init parse_crashkernel_simple(char *cmdline, 154 unsigned long long *crash_size, 155 unsigned long long *crash_base) 156 { 157 char *cur = cmdline; 158 159 *crash_size = memparse(cmdline, &cur); 160 if (cmdline == cur) { 161 pr_warn("crashkernel: memory value expected\n"); 162 return -EINVAL; 163 } 164 165 if (*cur == '@') 166 *crash_base = memparse(cur+1, &cur); 167 else if (*cur != ' ' && *cur != '\0') { 168 pr_warn("crashkernel: unrecognized char: %c\n", *cur); 169 return -EINVAL; 170 } 171 172 return 0; 173 } 174 175 #define SUFFIX_HIGH 0 176 #define SUFFIX_LOW 1 177 #define SUFFIX_CMA 2 178 #define SUFFIX_NULL 3 179 static __initdata char *suffix_tbl[] = { 180 [SUFFIX_HIGH] = ",high", 181 [SUFFIX_LOW] = ",low", 182 [SUFFIX_CMA] = ",cma", 183 [SUFFIX_NULL] = NULL, 184 }; 185 186 /* 187 * That function parses "suffix" crashkernel command lines like 188 * 189 * crashkernel=size,[high|low|cma] 190 * 191 * It returns 0 on success and -EINVAL on failure. 192 */ 193 static int __init parse_crashkernel_suffix(char *cmdline, 194 unsigned long long *crash_size, 195 const char *suffix) 196 { 197 char *cur = cmdline; 198 199 *crash_size = memparse(cmdline, &cur); 200 if (cmdline == cur) { 201 pr_warn("crashkernel: memory value expected\n"); 202 return -EINVAL; 203 } 204 205 /* check with suffix */ 206 if (strncmp(cur, suffix, strlen(suffix))) { 207 pr_warn("crashkernel: unrecognized char: %c\n", *cur); 208 return -EINVAL; 209 } 210 cur += strlen(suffix); 211 if (*cur != ' ' && *cur != '\0') { 212 pr_warn("crashkernel: unrecognized char: %c\n", *cur); 213 return -EINVAL; 214 } 215 216 return 0; 217 } 218 219 static __init char *get_last_crashkernel(char *cmdline, 220 const char *name, 221 const char *suffix) 222 { 223 char *p = cmdline, *ck_cmdline = NULL; 224 225 /* find crashkernel and use the last one if there are more */ 226 p = strstr(p, name); 227 while (p) { 228 char *end_p = strchr(p, ' '); 229 char *q; 230 231 if (!end_p) 232 end_p = p + strlen(p); 233 234 if (!suffix) { 235 int i; 236 237 /* skip the one with any known suffix */ 238 for (i = 0; suffix_tbl[i]; i++) { 239 q = end_p - strlen(suffix_tbl[i]); 240 if (!strncmp(q, suffix_tbl[i], 241 strlen(suffix_tbl[i]))) 242 goto next; 243 } 244 ck_cmdline = p; 245 } else { 246 q = end_p - strlen(suffix); 247 if (!strncmp(q, suffix, strlen(suffix))) 248 ck_cmdline = p; 249 } 250 next: 251 p = strstr(p+1, name); 252 } 253 254 return ck_cmdline; 255 } 256 257 static int __init __parse_crashkernel(char *cmdline, 258 unsigned long long system_ram, 259 unsigned long long *crash_size, 260 unsigned long long *crash_base, 261 const char *suffix) 262 { 263 char *first_colon, *first_space; 264 char *ck_cmdline; 265 char *name = "crashkernel="; 266 267 BUG_ON(!crash_size || !crash_base); 268 *crash_size = 0; 269 *crash_base = 0; 270 271 ck_cmdline = get_last_crashkernel(cmdline, name, suffix); 272 if (!ck_cmdline) 273 return -ENOENT; 274 275 ck_cmdline += strlen(name); 276 277 if (suffix) 278 return parse_crashkernel_suffix(ck_cmdline, crash_size, 279 suffix); 280 /* 281 * if the commandline contains a ':', then that's the extended 282 * syntax -- if not, it must be the classic syntax 283 */ 284 first_colon = strchr(ck_cmdline, ':'); 285 first_space = strchr(ck_cmdline, ' '); 286 if (first_colon && (!first_space || first_colon < first_space)) 287 return parse_crashkernel_mem(ck_cmdline, system_ram, 288 crash_size, crash_base); 289 290 return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base); 291 } 292 293 /* 294 * That function is the entry point for command line parsing and should be 295 * called from the arch-specific code. 296 * 297 * If crashkernel=,high|low is supported on architecture, non-NULL values 298 * should be passed to parameters 'low_size' and 'high'. 299 */ 300 int __init parse_crashkernel(char *cmdline, 301 unsigned long long system_ram, 302 unsigned long long *crash_size, 303 unsigned long long *crash_base, 304 unsigned long long *low_size, 305 unsigned long long *cma_size, 306 bool *high) 307 { 308 int ret; 309 unsigned long long __always_unused cma_base; 310 311 /* crashkernel=X[@offset] */ 312 ret = __parse_crashkernel(cmdline, system_ram, crash_size, 313 crash_base, NULL); 314 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 315 /* 316 * If non-NULL 'high' passed in and no normal crashkernel 317 * setting detected, try parsing crashkernel=,high|low. 318 */ 319 if (high && ret == -ENOENT) { 320 ret = __parse_crashkernel(cmdline, 0, crash_size, 321 crash_base, suffix_tbl[SUFFIX_HIGH]); 322 if (ret || !*crash_size) 323 return -EINVAL; 324 325 /* 326 * crashkernel=Y,low can be specified or not, but invalid value 327 * is not allowed. 328 */ 329 ret = __parse_crashkernel(cmdline, 0, low_size, 330 crash_base, suffix_tbl[SUFFIX_LOW]); 331 if (ret == -ENOENT) { 332 *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; 333 ret = 0; 334 } else if (ret) { 335 return ret; 336 } 337 338 *high = true; 339 } 340 341 /* 342 * optional CMA reservation 343 * cma_base is ignored 344 */ 345 if (cma_size) 346 __parse_crashkernel(cmdline, 0, cma_size, 347 &cma_base, suffix_tbl[SUFFIX_CMA]); 348 #endif 349 if (!*crash_size) 350 ret = -EINVAL; 351 352 if (*crash_size >= system_ram) 353 ret = -EINVAL; 354 355 return ret; 356 } 357 358 /* 359 * Add a dummy early_param handler to mark crashkernel= as a known command line 360 * parameter and suppress incorrect warnings in init/main.c. 361 */ 362 static int __init parse_crashkernel_dummy(char *arg) 363 { 364 return 0; 365 } 366 early_param("crashkernel", parse_crashkernel_dummy); 367 368 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 369 static int __init reserve_crashkernel_low(unsigned long long low_size) 370 { 371 #ifdef CONFIG_64BIT 372 unsigned long long low_base; 373 374 low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX); 375 if (!low_base) { 376 pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size); 377 return -ENOMEM; 378 } 379 380 pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n", 381 low_base, low_base + low_size, low_size >> 20); 382 383 crashk_low_res.start = low_base; 384 crashk_low_res.end = low_base + low_size - 1; 385 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY 386 insert_resource(&iomem_resource, &crashk_low_res); 387 #endif 388 #endif 389 return 0; 390 } 391 392 void __init reserve_crashkernel_generic(unsigned long long crash_size, 393 unsigned long long crash_base, 394 unsigned long long crash_low_size, 395 bool high) 396 { 397 unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0; 398 bool fixed_base = false; 399 400 /* User specifies base address explicitly. */ 401 if (crash_base) { 402 fixed_base = true; 403 search_base = crash_base; 404 search_end = crash_base + crash_size; 405 } else if (high) { 406 search_base = CRASH_ADDR_LOW_MAX; 407 search_end = CRASH_ADDR_HIGH_MAX; 408 } 409 410 retry: 411 crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, 412 search_base, search_end); 413 if (!crash_base) { 414 /* 415 * For crashkernel=size[KMG]@offset[KMG], print out failure 416 * message if can't reserve the specified region. 417 */ 418 if (fixed_base) { 419 pr_warn("crashkernel reservation failed - memory is in use.\n"); 420 return; 421 } 422 423 /* 424 * For crashkernel=size[KMG], if the first attempt was for 425 * low memory, fall back to high memory, the minimum required 426 * low memory will be reserved later. 427 */ 428 if (!high && search_end == CRASH_ADDR_LOW_MAX) { 429 search_end = CRASH_ADDR_HIGH_MAX; 430 search_base = CRASH_ADDR_LOW_MAX; 431 crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; 432 goto retry; 433 } 434 435 /* 436 * For crashkernel=size[KMG],high, if the first attempt was 437 * for high memory, fall back to low memory. 438 */ 439 if (high && search_end == CRASH_ADDR_HIGH_MAX) { 440 search_end = CRASH_ADDR_LOW_MAX; 441 search_base = 0; 442 if (search_end != CRASH_ADDR_HIGH_MAX) 443 goto retry; 444 } 445 pr_warn("cannot allocate crashkernel (size:0x%llx)\n", 446 crash_size); 447 return; 448 } 449 450 if ((crash_base >= CRASH_ADDR_LOW_MAX) && 451 crash_low_size && reserve_crashkernel_low(crash_low_size)) { 452 memblock_phys_free(crash_base, crash_size); 453 return; 454 } 455 456 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", 457 crash_base, crash_base + crash_size, crash_size >> 20); 458 459 /* 460 * The crashkernel memory will be removed from the kernel linear 461 * map. Inform kmemleak so that it won't try to access it. 462 */ 463 kmemleak_ignore_phys(crash_base); 464 if (crashk_low_res.end) 465 kmemleak_ignore_phys(crashk_low_res.start); 466 467 crashk_res.start = crash_base; 468 crashk_res.end = crash_base + crash_size - 1; 469 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY 470 insert_resource(&iomem_resource, &crashk_res); 471 #endif 472 } 473 474 struct range crashk_cma_ranges[CRASHKERNEL_CMA_RANGES_MAX]; 475 #ifdef CRASHKERNEL_CMA 476 int crashk_cma_cnt; 477 void __init reserve_crashkernel_cma(unsigned long long cma_size) 478 { 479 unsigned long long request_size = roundup(cma_size, PAGE_SIZE); 480 unsigned long long reserved_size = 0; 481 482 if (!cma_size) 483 return; 484 485 while (cma_size > reserved_size && 486 crashk_cma_cnt < CRASHKERNEL_CMA_RANGES_MAX) { 487 488 struct cma *res; 489 490 if (cma_declare_contiguous(0, request_size, 0, 0, 0, false, 491 "crashkernel", &res)) { 492 /* reservation failed, try half-sized blocks */ 493 if (request_size <= PAGE_SIZE) 494 break; 495 496 request_size = roundup(request_size / 2, PAGE_SIZE); 497 continue; 498 } 499 500 crashk_cma_ranges[crashk_cma_cnt].start = cma_get_base(res); 501 crashk_cma_ranges[crashk_cma_cnt].end = 502 crashk_cma_ranges[crashk_cma_cnt].start + 503 cma_get_size(res) - 1; 504 ++crashk_cma_cnt; 505 reserved_size += request_size; 506 } 507 508 if (cma_size > reserved_size) 509 pr_warn("crashkernel CMA reservation failed: %lld MB requested, %lld MB reserved in %d ranges\n", 510 cma_size >> 20, reserved_size >> 20, crashk_cma_cnt); 511 else 512 pr_info("crashkernel CMA reserved: %lld MB in %d ranges\n", 513 reserved_size >> 20, crashk_cma_cnt); 514 } 515 516 #else /* CRASHKERNEL_CMA */ 517 void __init reserve_crashkernel_cma(unsigned long long cma_size) 518 { 519 if (cma_size) 520 pr_warn("crashkernel CMA reservation not supported\n"); 521 } 522 #endif 523 524 #ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY 525 static __init int insert_crashkernel_resources(void) 526 { 527 if (crashk_res.start < crashk_res.end) 528 insert_resource(&iomem_resource, &crashk_res); 529 530 if (crashk_low_res.start < crashk_low_res.end) 531 insert_resource(&iomem_resource, &crashk_low_res); 532 533 return 0; 534 } 535 early_initcall(insert_crashkernel_resources); 536 #endif 537 #endif 538