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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * crash.c - kernel crash support code.
4 * Copyright (C) 2002-2004 Eric Biederman <[email protected]>
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 */
27struct 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};
34struct 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 */
56static 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 */
151static 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
177static __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 */
191static 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
217static __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 }
248next:
249 p = strstr(p+1, name);
250 }
251
252 return ck_cmdline;
253}
254
255static 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 */
298int __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 */
360static int __init parse_crashkernel_dummy(char *arg)
361{
362 return 0;
363}
364early_param("crashkernel", parse_crashkernel_dummy);
365
366#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
367static 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
390void __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
408retry:
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
472struct range crashk_cma_ranges[CRASHKERNEL_CMA_RANGES_MAX];
473#ifdef CRASHKERNEL_CMA
474int crashk_cma_cnt;
475void __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 */
515void __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
523static __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}
536early_initcall(insert_crashkernel_resources);
537#endif
538#endif