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 */
parse_crashkernel_mem(char * cmdline,unsigned long long system_ram,unsigned long long * crash_size,unsigned long long * crash_base)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 */
parse_crashkernel_simple(char * cmdline,unsigned long long * crash_size,unsigned long long * crash_base)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 */
parse_crashkernel_suffix(char * cmdline,unsigned long long * crash_size,const char * suffix)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
get_last_crashkernel(char * cmdline,const char * name,const char * suffix)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
__parse_crashkernel(char * cmdline,unsigned long long system_ram,unsigned long long * crash_size,unsigned long long * crash_base,const char * suffix)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 */
parse_crashkernel(char * cmdline,unsigned long long system_ram,unsigned long long * crash_size,unsigned long long * crash_base,unsigned long long * low_size,bool * high)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 */
parse_crashkernel_dummy(char * arg)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
reserve_crashkernel_low(unsigned long long low_size)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
reserve_crashkernel_generic(char * cmdline,unsigned long long crash_size,unsigned long long crash_base,unsigned long long crash_low_size,bool high)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
insert_crashkernel_resources(void)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
472