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 insert_resource(&iomem_resource, &crashk_low_res); 370 #endif 371 return 0; 372 } 373 374 void __init reserve_crashkernel_generic(char *cmdline, 375 unsigned long long crash_size, 376 unsigned long long crash_base, 377 unsigned long long crash_low_size, 378 bool high) 379 { 380 unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0; 381 bool fixed_base = false; 382 383 /* User specifies base address explicitly. */ 384 if (crash_base) { 385 fixed_base = true; 386 search_base = crash_base; 387 search_end = crash_base + crash_size; 388 } else if (high) { 389 search_base = CRASH_ADDR_LOW_MAX; 390 search_end = CRASH_ADDR_HIGH_MAX; 391 } 392 393 retry: 394 crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, 395 search_base, search_end); 396 if (!crash_base) { 397 /* 398 * For crashkernel=size[KMG]@offset[KMG], print out failure 399 * message if can't reserve the specified region. 400 */ 401 if (fixed_base) { 402 pr_warn("crashkernel reservation failed - memory is in use.\n"); 403 return; 404 } 405 406 /* 407 * For crashkernel=size[KMG], if the first attempt was for 408 * low memory, fall back to high memory, the minimum required 409 * low memory will be reserved later. 410 */ 411 if (!high && search_end == CRASH_ADDR_LOW_MAX) { 412 search_end = CRASH_ADDR_HIGH_MAX; 413 search_base = CRASH_ADDR_LOW_MAX; 414 crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; 415 goto retry; 416 } 417 418 /* 419 * For crashkernel=size[KMG],high, if the first attempt was 420 * for high memory, fall back to low memory. 421 */ 422 if (high && search_end == CRASH_ADDR_HIGH_MAX) { 423 search_end = CRASH_ADDR_LOW_MAX; 424 search_base = 0; 425 goto retry; 426 } 427 pr_warn("cannot allocate crashkernel (size:0x%llx)\n", 428 crash_size); 429 return; 430 } 431 432 if ((crash_base >= CRASH_ADDR_LOW_MAX) && 433 crash_low_size && reserve_crashkernel_low(crash_low_size)) { 434 memblock_phys_free(crash_base, crash_size); 435 return; 436 } 437 438 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", 439 crash_base, crash_base + crash_size, crash_size >> 20); 440 441 /* 442 * The crashkernel memory will be removed from the kernel linear 443 * map. Inform kmemleak so that it won't try to access it. 444 */ 445 kmemleak_ignore_phys(crash_base); 446 if (crashk_low_res.end) 447 kmemleak_ignore_phys(crashk_low_res.start); 448 449 crashk_res.start = crash_base; 450 crashk_res.end = crash_base + crash_size - 1; 451 } 452 453 static __init int insert_crashkernel_resources(void) 454 { 455 if (crashk_res.start < crashk_res.end) 456 insert_resource(&iomem_resource, &crashk_res); 457 458 if (crashk_low_res.start < crashk_low_res.end) 459 insert_resource(&iomem_resource, &crashk_low_res); 460 461 return 0; 462 } 463 early_initcall(insert_crashkernel_resources); 464 #endif 465