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 "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("crashkernel: 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_CMA 2 176 #define SUFFIX_NULL 3 177 static __initdata char *suffix_tbl[] = { 178 [SUFFIX_HIGH] = ",high", 179 [SUFFIX_LOW] = ",low", 180 [SUFFIX_CMA] = ",cma", 181 [SUFFIX_NULL] = NULL, 182 }; 183 184 /* 185 * That function parses "suffix" crashkernel command lines like 186 * 187 * crashkernel=size,[high|low|cma] 188 * 189 * It returns 0 on success and -EINVAL on failure. 190 */ 191 static int __init parse_crashkernel_suffix(char *cmdline, 192 unsigned long long *crash_size, 193 const char *suffix) 194 { 195 char *cur = cmdline; 196 197 *crash_size = memparse(cmdline, &cur); 198 if (cmdline == cur) { 199 pr_warn("crashkernel: memory value expected\n"); 200 return -EINVAL; 201 } 202 203 /* check with suffix */ 204 if (strncmp(cur, suffix, strlen(suffix))) { 205 pr_warn("crashkernel: unrecognized char: %c\n", *cur); 206 return -EINVAL; 207 } 208 cur += strlen(suffix); 209 if (*cur != ' ' && *cur != '\0') { 210 pr_warn("crashkernel: unrecognized char: %c\n", *cur); 211 return -EINVAL; 212 } 213 214 return 0; 215 } 216 217 static __init char *get_last_crashkernel(char *cmdline, 218 const char *name, 219 const char *suffix) 220 { 221 char *p = cmdline, *ck_cmdline = NULL; 222 223 /* find crashkernel and use the last one if there are more */ 224 p = strstr(p, name); 225 while (p) { 226 char *end_p = strchr(p, ' '); 227 char *q; 228 229 if (!end_p) 230 end_p = p + strlen(p); 231 232 if (!suffix) { 233 int i; 234 235 /* skip the one with any known suffix */ 236 for (i = 0; suffix_tbl[i]; i++) { 237 q = end_p - strlen(suffix_tbl[i]); 238 if (!strncmp(q, suffix_tbl[i], 239 strlen(suffix_tbl[i]))) 240 goto next; 241 } 242 ck_cmdline = p; 243 } else { 244 q = end_p - strlen(suffix); 245 if (!strncmp(q, suffix, strlen(suffix))) 246 ck_cmdline = p; 247 } 248 next: 249 p = strstr(p+1, name); 250 } 251 252 return ck_cmdline; 253 } 254 255 static int __init __parse_crashkernel(char *cmdline, 256 unsigned long long system_ram, 257 unsigned long long *crash_size, 258 unsigned long long *crash_base, 259 const char *suffix) 260 { 261 char *first_colon, *first_space; 262 char *ck_cmdline; 263 char *name = "crashkernel="; 264 265 BUG_ON(!crash_size || !crash_base); 266 *crash_size = 0; 267 *crash_base = 0; 268 269 ck_cmdline = get_last_crashkernel(cmdline, name, suffix); 270 if (!ck_cmdline) 271 return -ENOENT; 272 273 ck_cmdline += strlen(name); 274 275 if (suffix) 276 return parse_crashkernel_suffix(ck_cmdline, crash_size, 277 suffix); 278 /* 279 * if the commandline contains a ':', then that's the extended 280 * syntax -- if not, it must be the classic syntax 281 */ 282 first_colon = strchr(ck_cmdline, ':'); 283 first_space = strchr(ck_cmdline, ' '); 284 if (first_colon && (!first_space || first_colon < first_space)) 285 return parse_crashkernel_mem(ck_cmdline, system_ram, 286 crash_size, crash_base); 287 288 return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base); 289 } 290 291 /* 292 * That function is the entry point for command line parsing and should be 293 * called from the arch-specific code. 294 * 295 * If crashkernel=,high|low is supported on architecture, non-NULL values 296 * should be passed to parameters 'low_size' and 'high'. 297 */ 298 int __init parse_crashkernel(char *cmdline, 299 unsigned long long system_ram, 300 unsigned long long *crash_size, 301 unsigned long long *crash_base, 302 unsigned long long *low_size, 303 unsigned long long *cma_size, 304 bool *high) 305 { 306 int ret; 307 unsigned long long __always_unused cma_base; 308 309 /* crashkernel=X[@offset] */ 310 ret = __parse_crashkernel(cmdline, system_ram, crash_size, 311 crash_base, NULL); 312 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 313 /* 314 * If non-NULL 'high' passed in and no normal crashkernel 315 * setting detected, try parsing crashkernel=,high|low. 316 */ 317 if (high && ret == -ENOENT) { 318 ret = __parse_crashkernel(cmdline, 0, crash_size, 319 crash_base, suffix_tbl[SUFFIX_HIGH]); 320 if (ret || !*crash_size) 321 return -EINVAL; 322 323 /* 324 * crashkernel=Y,low can be specified or not, but invalid value 325 * is not allowed. 326 */ 327 ret = __parse_crashkernel(cmdline, 0, low_size, 328 crash_base, suffix_tbl[SUFFIX_LOW]); 329 if (ret == -ENOENT) { 330 *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; 331 ret = 0; 332 } else if (ret) { 333 return ret; 334 } 335 336 *high = true; 337 } 338 339 /* 340 * optional CMA reservation 341 * cma_base is ignored 342 */ 343 if (cma_size) 344 __parse_crashkernel(cmdline, 0, cma_size, 345 &cma_base, suffix_tbl[SUFFIX_CMA]); 346 #endif 347 if (!*crash_size) 348 ret = -EINVAL; 349 350 if (*crash_size >= system_ram) 351 ret = -EINVAL; 352 353 return ret; 354 } 355 356 /* 357 * Add a dummy early_param handler to mark crashkernel= as a known command line 358 * parameter and suppress incorrect warnings in init/main.c. 359 */ 360 static int __init parse_crashkernel_dummy(char *arg) 361 { 362 return 0; 363 } 364 early_param("crashkernel", parse_crashkernel_dummy); 365 366 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 367 static int __init reserve_crashkernel_low(unsigned long long low_size) 368 { 369 #ifdef CONFIG_64BIT 370 unsigned long long low_base; 371 372 low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX); 373 if (!low_base) { 374 pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size); 375 return -ENOMEM; 376 } 377 378 pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n", 379 low_base, low_base + low_size, low_size >> 20); 380 381 crashk_low_res.start = low_base; 382 crashk_low_res.end = low_base + low_size - 1; 383 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY 384 insert_resource(&iomem_resource, &crashk_low_res); 385 #endif 386 #endif 387 return 0; 388 } 389 390 void __init reserve_crashkernel_generic(unsigned long long crash_size, 391 unsigned long long crash_base, 392 unsigned long long crash_low_size, 393 bool high) 394 { 395 unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0; 396 bool fixed_base = false; 397 398 /* User specifies base address explicitly. */ 399 if (crash_base) { 400 fixed_base = true; 401 search_base = crash_base; 402 search_end = crash_base + crash_size; 403 } else if (high) { 404 search_base = CRASH_ADDR_LOW_MAX; 405 search_end = CRASH_ADDR_HIGH_MAX; 406 } 407 408 retry: 409 crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, 410 search_base, search_end); 411 if (!crash_base) { 412 /* 413 * For crashkernel=size[KMG]@offset[KMG], print out failure 414 * message if can't reserve the specified region. 415 */ 416 if (fixed_base) { 417 pr_warn("crashkernel reservation failed - memory is in use.\n"); 418 return; 419 } 420 421 /* 422 * For crashkernel=size[KMG], if the first attempt was for 423 * low memory, fall back to high memory, the minimum required 424 * low memory will be reserved later. 425 */ 426 if (!high && search_end == CRASH_ADDR_LOW_MAX) { 427 search_end = CRASH_ADDR_HIGH_MAX; 428 search_base = CRASH_ADDR_LOW_MAX; 429 crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; 430 goto retry; 431 } 432 433 /* 434 * For crashkernel=size[KMG],high, if the first attempt was 435 * for high memory, fall back to low memory. 436 */ 437 if (high && search_end == CRASH_ADDR_HIGH_MAX) { 438 search_end = CRASH_ADDR_LOW_MAX; 439 search_base = 0; 440 if (search_end != CRASH_ADDR_HIGH_MAX) 441 goto retry; 442 } 443 pr_warn("cannot allocate crashkernel (size:0x%llx)\n", 444 crash_size); 445 return; 446 } 447 448 if ((crash_base >= CRASH_ADDR_LOW_MAX) && 449 crash_low_size && reserve_crashkernel_low(crash_low_size)) { 450 memblock_phys_free(crash_base, crash_size); 451 return; 452 } 453 454 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", 455 crash_base, crash_base + crash_size, crash_size >> 20); 456 457 /* 458 * The crashkernel memory will be removed from the kernel linear 459 * map. Inform kmemleak so that it won't try to access it. 460 */ 461 kmemleak_ignore_phys(crash_base); 462 if (crashk_low_res.end) 463 kmemleak_ignore_phys(crashk_low_res.start); 464 465 crashk_res.start = crash_base; 466 crashk_res.end = crash_base + crash_size - 1; 467 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY 468 insert_resource(&iomem_resource, &crashk_res); 469 #endif 470 } 471 472 struct range crashk_cma_ranges[CRASHKERNEL_CMA_RANGES_MAX]; 473 #ifdef CRASHKERNEL_CMA 474 int crashk_cma_cnt; 475 void __init reserve_crashkernel_cma(unsigned long long cma_size) 476 { 477 unsigned long long request_size = roundup(cma_size, PAGE_SIZE); 478 unsigned long long reserved_size = 0; 479 480 if (!cma_size) 481 return; 482 483 while (cma_size > reserved_size && 484 crashk_cma_cnt < CRASHKERNEL_CMA_RANGES_MAX) { 485 486 struct cma *res; 487 488 if (cma_declare_contiguous(0, request_size, 0, 0, 0, false, 489 "crashkernel", &res)) { 490 /* reservation failed, try half-sized blocks */ 491 if (request_size <= PAGE_SIZE) 492 break; 493 494 request_size = roundup(request_size / 2, PAGE_SIZE); 495 continue; 496 } 497 498 crashk_cma_ranges[crashk_cma_cnt].start = cma_get_base(res); 499 crashk_cma_ranges[crashk_cma_cnt].end = 500 crashk_cma_ranges[crashk_cma_cnt].start + 501 cma_get_size(res) - 1; 502 ++crashk_cma_cnt; 503 reserved_size += request_size; 504 } 505 506 if (cma_size > reserved_size) 507 pr_warn("crashkernel CMA reservation failed: %lld MB requested, %lld MB reserved in %d ranges\n", 508 cma_size >> 20, reserved_size >> 20, crashk_cma_cnt); 509 else 510 pr_info("crashkernel CMA reserved: %lld MB in %d ranges\n", 511 reserved_size >> 20, crashk_cma_cnt); 512 } 513 514 #else /* CRASHKERNEL_CMA */ 515 void __init reserve_crashkernel_cma(unsigned long long cma_size) 516 { 517 if (cma_size) 518 pr_warn("crashkernel CMA reservation not supported\n"); 519 } 520 #endif 521 522 #ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY 523 static __init int insert_crashkernel_resources(void) 524 { 525 if (!arch_add_crash_res_to_iomem()) 526 return 0; 527 528 if (crashk_res.start < crashk_res.end) 529 insert_resource(&iomem_resource, &crashk_res); 530 531 if (crashk_low_res.start < crashk_low_res.end) 532 insert_resource(&iomem_resource, &crashk_low_res); 533 534 return 0; 535 } 536 early_initcall(insert_crashkernel_resources); 537 #endif 538 #endif 539