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 */
29struct 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};
36struct 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 */
58static 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(ptr: cur, retptr: &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(ptr: cur, retptr: &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(ptr: cur, retptr: &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(ptr: cur, retptr: &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 */
153static 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(ptr: cmdline, retptr: &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(ptr: cur+1, retptr: &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
179static __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 */
193static 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(ptr: cmdline, retptr: &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
219static __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 }
250next:
251 p = strstr(p+1, name);
252 }
253
254 return ck_cmdline;
255}
256
257static 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(cmdline: 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(cmdline: ck_cmdline, system_ram,
288 crash_size, crash_base);
289
290 return parse_crashkernel_simple(cmdline: 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 */
300int __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, system_ram: 0, crash_size,
321 crash_base, suffix: 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, system_ram: 0, crash_size: low_size,
330 crash_base, suffix: 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, system_ram: 0, crash_size: cma_size,
347 crash_base: &cma_base, suffix: 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 */
362static int __init parse_crashkernel_dummy(char *arg)
363{
364 return 0;
365}
366early_param("crashkernel", parse_crashkernel_dummy);
367
368#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
369static 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(size: low_size, CRASH_ALIGN, start: 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(parent: &iomem_resource, new: &crashk_low_res);
387#endif
388#endif
389 return 0;
390}
391
392void __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
410retry:
411 crash_base = memblock_phys_alloc_range(size: crash_size, CRASH_ALIGN,
412 start: search_base, end: 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(low_size: crash_low_size)) {
452 memblock_phys_free(base: crash_base, size: 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(phys: crash_base);
464 if (crashk_low_res.end)
465 kmemleak_ignore_phys(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(parent: &iomem_resource, new: &crashk_res);
471#endif
472}
473
474struct range crashk_cma_ranges[CRASHKERNEL_CMA_RANGES_MAX];
475#ifdef CRASHKERNEL_CMA
476int crashk_cma_cnt;
477void __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 */
517void __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
525static __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}
535early_initcall(insert_crashkernel_resources);
536#endif
537#endif
538