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
18 #include <asm/page.h>
19 #include <asm/sections.h>
20
21 #include <crypto/sha1.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("crahskernel: 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_NULL 2
176 static __initdata char *suffix_tbl[] = {
177 [SUFFIX_HIGH] = ",high",
178 [SUFFIX_LOW] = ",low",
179 [SUFFIX_NULL] = NULL,
180 };
181
182 /*
183 * That function parses "suffix" crashkernel command lines like
184 *
185 * crashkernel=size,[high|low]
186 *
187 * It returns 0 on success and -EINVAL on failure.
188 */
189 static int __init parse_crashkernel_suffix(char *cmdline,
190 unsigned long long *crash_size,
191 const char *suffix)
192 {
193 char *cur = cmdline;
194
195 *crash_size = memparse(cmdline, &cur);
196 if (cmdline == cur) {
197 pr_warn("crashkernel: memory value expected\n");
198 return -EINVAL;
199 }
200
201 /* check with suffix */
202 if (strncmp(cur, suffix, strlen(suffix))) {
203 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
204 return -EINVAL;
205 }
206 cur += strlen(suffix);
207 if (*cur != ' ' && *cur != '\0') {
208 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
209 return -EINVAL;
210 }
211
212 return 0;
213 }
214
215 static __init char *get_last_crashkernel(char *cmdline,
216 const char *name,
217 const char *suffix)
218 {
219 char *p = cmdline, *ck_cmdline = NULL;
220
221 /* find crashkernel and use the last one if there are more */
222 p = strstr(p, name);
223 while (p) {
224 char *end_p = strchr(p, ' ');
225 char *q;
226
227 if (!end_p)
228 end_p = p + strlen(p);
229
230 if (!suffix) {
231 int i;
232
233 /* skip the one with any known suffix */
234 for (i = 0; suffix_tbl[i]; i++) {
235 q = end_p - strlen(suffix_tbl[i]);
236 if (!strncmp(q, suffix_tbl[i],
237 strlen(suffix_tbl[i])))
238 goto next;
239 }
240 ck_cmdline = p;
241 } else {
242 q = end_p - strlen(suffix);
243 if (!strncmp(q, suffix, strlen(suffix)))
244 ck_cmdline = p;
245 }
246 next:
247 p = strstr(p+1, name);
248 }
249
250 return ck_cmdline;
251 }
252
253 static int __init __parse_crashkernel(char *cmdline,
254 unsigned long long system_ram,
255 unsigned long long *crash_size,
256 unsigned long long *crash_base,
257 const char *suffix)
258 {
259 char *first_colon, *first_space;
260 char *ck_cmdline;
261 char *name = "crashkernel=";
262
263 BUG_ON(!crash_size || !crash_base);
264 *crash_size = 0;
265 *crash_base = 0;
266
267 ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
268 if (!ck_cmdline)
269 return -ENOENT;
270
271 ck_cmdline += strlen(name);
272
273 if (suffix)
274 return parse_crashkernel_suffix(ck_cmdline, crash_size,
275 suffix);
276 /*
277 * if the commandline contains a ':', then that's the extended
278 * syntax -- if not, it must be the classic syntax
279 */
280 first_colon = strchr(ck_cmdline, ':');
281 first_space = strchr(ck_cmdline, ' ');
282 if (first_colon && (!first_space || first_colon < first_space))
283 return parse_crashkernel_mem(ck_cmdline, system_ram,
284 crash_size, crash_base);
285
286 return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
287 }
288
289 /*
290 * That function is the entry point for command line parsing and should be
291 * called from the arch-specific code.
292 *
293 * If crashkernel=,high|low is supported on architecture, non-NULL values
294 * should be passed to parameters 'low_size' and 'high'.
295 */
296 int __init parse_crashkernel(char *cmdline,
297 unsigned long long system_ram,
298 unsigned long long *crash_size,
299 unsigned long long *crash_base,
300 unsigned long long *low_size,
301 bool *high)
302 {
303 int ret;
304
305 /* crashkernel=X[@offset] */
306 ret = __parse_crashkernel(cmdline, system_ram, crash_size,
307 crash_base, NULL);
308 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
309 /*
310 * If non-NULL 'high' passed in and no normal crashkernel
311 * setting detected, try parsing crashkernel=,high|low.
312 */
313 if (high && ret == -ENOENT) {
314 ret = __parse_crashkernel(cmdline, 0, crash_size,
315 crash_base, suffix_tbl[SUFFIX_HIGH]);
316 if (ret || !*crash_size)
317 return -EINVAL;
318
319 /*
320 * crashkernel=Y,low can be specified or not, but invalid value
321 * is not allowed.
322 */
323 ret = __parse_crashkernel(cmdline, 0, low_size,
324 crash_base, suffix_tbl[SUFFIX_LOW]);
325 if (ret == -ENOENT) {
326 *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
327 ret = 0;
328 } else if (ret) {
329 return ret;
330 }
331
332 *high = true;
333 }
334 #endif
335 if (!*crash_size)
336 ret = -EINVAL;
337
338 return ret;
339 }
340
341 /*
342 * Add a dummy early_param handler to mark crashkernel= as a known command line
343 * parameter and suppress incorrect warnings in init/main.c.
344 */
345 static int __init parse_crashkernel_dummy(char *arg)
346 {
347 return 0;
348 }
349 early_param("crashkernel", parse_crashkernel_dummy);
350
351 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
352 static int __init reserve_crashkernel_low(unsigned long long low_size)
353 {
354 #ifdef CONFIG_64BIT
355 unsigned long long low_base;
356
357 low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
358 if (!low_base) {
359 pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
360 return -ENOMEM;
361 }
362
363 pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
364 low_base, low_base + low_size, low_size >> 20);
365
366 crashk_low_res.start = low_base;
367 crashk_low_res.end = low_base + low_size - 1;
368 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
369 insert_resource(&iomem_resource, &crashk_low_res);
370 #endif
371 #endif
372 return 0;
373 }
374
375 void __init reserve_crashkernel_generic(char *cmdline,
376 unsigned long long crash_size,
377 unsigned long long crash_base,
378 unsigned long long crash_low_size,
379 bool high)
380 {
381 unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
382 bool fixed_base = false;
383
384 /* User specifies base address explicitly. */
385 if (crash_base) {
386 fixed_base = true;
387 search_base = crash_base;
388 search_end = crash_base + crash_size;
389 } else if (high) {
390 search_base = CRASH_ADDR_LOW_MAX;
391 search_end = CRASH_ADDR_HIGH_MAX;
392 }
393
394 retry:
395 crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
396 search_base, search_end);
397 if (!crash_base) {
398 /*
399 * For crashkernel=size[KMG]@offset[KMG], print out failure
400 * message if can't reserve the specified region.
401 */
402 if (fixed_base) {
403 pr_warn("crashkernel reservation failed - memory is in use.\n");
404 return;
405 }
406
407 /*
408 * For crashkernel=size[KMG], if the first attempt was for
409 * low memory, fall back to high memory, the minimum required
410 * low memory will be reserved later.
411 */
412 if (!high && search_end == CRASH_ADDR_LOW_MAX) {
413 search_end = CRASH_ADDR_HIGH_MAX;
414 search_base = CRASH_ADDR_LOW_MAX;
415 crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
416 goto retry;
417 }
418
419 /*
420 * For crashkernel=size[KMG],high, if the first attempt was
421 * for high memory, fall back to low memory.
422 */
423 if (high && search_end == CRASH_ADDR_HIGH_MAX) {
424 search_end = CRASH_ADDR_LOW_MAX;
425 search_base = 0;
426 goto retry;
427 }
428 pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
429 crash_size);
430 return;
431 }
432
433 if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
434 crash_low_size && reserve_crashkernel_low(crash_low_size)) {
435 memblock_phys_free(crash_base, crash_size);
436 return;
437 }
438
439 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
440 crash_base, crash_base + crash_size, crash_size >> 20);
441
442 /*
443 * The crashkernel memory will be removed from the kernel linear
444 * map. Inform kmemleak so that it won't try to access it.
445 */
446 kmemleak_ignore_phys(crash_base);
447 if (crashk_low_res.end)
448 kmemleak_ignore_phys(crashk_low_res.start);
449
450 crashk_res.start = crash_base;
451 crashk_res.end = crash_base + crash_size - 1;
452 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
453 insert_resource(&iomem_resource, &crashk_res);
454 #endif
455 }
456
457 #ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
458 static __init int insert_crashkernel_resources(void)
459 {
460 if (crashk_res.start < crashk_res.end)
461 insert_resource(&iomem_resource, &crashk_res);
462
463 if (crashk_low_res.start < crashk_low_res.end)
464 insert_resource(&iomem_resource, &crashk_low_res);
465
466 return 0;
467 }
468 early_initcall(insert_crashkernel_resources);
469 #endif
470 #endif
471
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