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 */
28struct 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};
35struct 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 */
57static 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 */
152static 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
177static __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 */
190static 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
216static __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		}
247next:
248		p = strstr(p+1, name);
249	}
250
251	return ck_cmdline;
252}
253
254static 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 */
297int __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 */
346static int __init parse_crashkernel_dummy(char *arg)
347{
348	return 0;
349}
350early_param("crashkernel", parse_crashkernel_dummy);
351
352#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
353static 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
376void __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
395retry:
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
459static __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}
469early_initcall(insert_crashkernel_resources);
470#endif
471#endif
472