crash_reserve.c

  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(cur, &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(cur, &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(cur, &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(cur, &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(cmdline, &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(cur+1, &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(cmdline, &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(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(ck_cmdline, system_ram,
288				crash_size, crash_base);
289
290	return parse_crashkernel_simple(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, 0, crash_size,
321				crash_base, 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, 0, low_size,
330				crash_base, 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, 0, cma_size,
347			&cma_base, 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(low_size, CRASH_ALIGN, 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(&iomem_resource, &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(crash_size, CRASH_ALIGN,
412					       search_base, 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(crash_low_size)) {
452		memblock_phys_free(crash_base, 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(crash_base);
464	if (crashk_low_res.end)
465		kmemleak_ignore_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(&iomem_resource, &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 (!arch_add_crash_res_to_iomem())
528		return 0;
529
530	if (crashk_res.start < crashk_res.end)
531		insert_resource(&iomem_resource, &crashk_res);
532
533	if (crashk_low_res.start < crashk_low_res.end)
534		insert_resource(&iomem_resource, &crashk_low_res);
535
536	return 0;
537}
538early_initcall(insert_crashkernel_resources);
539#endif
540#endif