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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 <ebiederm@xmission.com>
5 */
6
7#include <linux/buildid.h>
8#include <linux/crash_core.h>
9#include <linux/init.h>
10#include <linux/utsname.h>
11#include <linux/vmalloc.h>
12#include <linux/sizes.h>
13
14#include <asm/page.h>
15#include <asm/sections.h>
16
17#include <crypto/sha1.h>
18
19#include "kallsyms_internal.h"
20
21/* vmcoreinfo stuff */
22unsigned char *vmcoreinfo_data;
23size_t vmcoreinfo_size;
24u32 *vmcoreinfo_note;
25
26/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
27static unsigned char *vmcoreinfo_data_safecopy;
28
29/*
30 * parsing the "crashkernel" commandline
31 *
32 * this code is intended to be called from architecture specific code
33 */
34
35
36/*
37 * This function parses command lines in the format
38 *
39 * crashkernel=ramsize-range:size[,...][@offset]
40 *
41 * The function returns 0 on success and -EINVAL on failure.
42 */
43static int __init parse_crashkernel_mem(char *cmdline,
44 unsigned long long system_ram,
45 unsigned long long *crash_size,
46 unsigned long long *crash_base)
47{
48 char *cur = cmdline, *tmp;
49 unsigned long long total_mem = system_ram;
50
51 /*
52 * Firmware sometimes reserves some memory regions for its own use,
53 * so the system memory size is less than the actual physical memory
54 * size. Work around this by rounding up the total size to 128M,
55 * which is enough for most test cases.
56 */
57 total_mem = roundup(total_mem, SZ_128M);
58
59 /* for each entry of the comma-separated list */
60 do {
61 unsigned long long start, end = ULLONG_MAX, size;
62
63 /* get the start of the range */
64 start = memparse(cur, &tmp);
65 if (cur == tmp) {
66 pr_warn("crashkernel: Memory value expected\n");
67 return -EINVAL;
68 }
69 cur = tmp;
70 if (*cur != '-') {
71 pr_warn("crashkernel: '-' expected\n");
72 return -EINVAL;
73 }
74 cur++;
75
76 /* if no ':' is here, than we read the end */
77 if (*cur != ':') {
78 end = memparse(cur, &tmp);
79 if (cur == tmp) {
80 pr_warn("crashkernel: Memory value expected\n");
81 return -EINVAL;
82 }
83 cur = tmp;
84 if (end <= start) {
85 pr_warn("crashkernel: end <= start\n");
86 return -EINVAL;
87 }
88 }
89
90 if (*cur != ':') {
91 pr_warn("crashkernel: ':' expected\n");
92 return -EINVAL;
93 }
94 cur++;
95
96 size = memparse(cur, &tmp);
97 if (cur == tmp) {
98 pr_warn("Memory value expected\n");
99 return -EINVAL;
100 }
101 cur = tmp;
102 if (size >= total_mem) {
103 pr_warn("crashkernel: invalid size\n");
104 return -EINVAL;
105 }
106
107 /* match ? */
108 if (total_mem >= start && total_mem < end) {
109 *crash_size = size;
110 break;
111 }
112 } while (*cur++ == ',');
113
114 if (*crash_size > 0) {
115 while (*cur && *cur != ' ' && *cur != '@')
116 cur++;
117 if (*cur == '@') {
118 cur++;
119 *crash_base = memparse(cur, &tmp);
120 if (cur == tmp) {
121 pr_warn("Memory value expected after '@'\n");
122 return -EINVAL;
123 }
124 }
125 } else
126 pr_info("crashkernel size resulted in zero bytes\n");
127
128 return 0;
129}
130
131/*
132 * That function parses "simple" (old) crashkernel command lines like
133 *
134 * crashkernel=size[@offset]
135 *
136 * It returns 0 on success and -EINVAL on failure.
137 */
138static int __init parse_crashkernel_simple(char *cmdline,
139 unsigned long long *crash_size,
140 unsigned long long *crash_base)
141{
142 char *cur = cmdline;
143
144 *crash_size = memparse(cmdline, &cur);
145 if (cmdline == cur) {
146 pr_warn("crashkernel: memory value expected\n");
147 return -EINVAL;
148 }
149
150 if (*cur == '@')
151 *crash_base = memparse(cur+1, &cur);
152 else if (*cur != ' ' && *cur != '\0') {
153 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
154 return -EINVAL;
155 }
156
157 return 0;
158}
159
160#define SUFFIX_HIGH 0
161#define SUFFIX_LOW 1
162#define SUFFIX_NULL 2
163static __initdata char *suffix_tbl[] = {
164 [SUFFIX_HIGH] = ",high",
165 [SUFFIX_LOW] = ",low",
166 [SUFFIX_NULL] = NULL,
167};
168
169/*
170 * That function parses "suffix" crashkernel command lines like
171 *
172 * crashkernel=size,[high|low]
173 *
174 * It returns 0 on success and -EINVAL on failure.
175 */
176static int __init parse_crashkernel_suffix(char *cmdline,
177 unsigned long long *crash_size,
178 const char *suffix)
179{
180 char *cur = cmdline;
181
182 *crash_size = memparse(cmdline, &cur);
183 if (cmdline == cur) {
184 pr_warn("crashkernel: memory value expected\n");
185 return -EINVAL;
186 }
187
188 /* check with suffix */
189 if (strncmp(cur, suffix, strlen(suffix))) {
190 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
191 return -EINVAL;
192 }
193 cur += strlen(suffix);
194 if (*cur != ' ' && *cur != '\0') {
195 pr_warn("crashkernel: unrecognized char: %c\n", *cur);
196 return -EINVAL;
197 }
198
199 return 0;
200}
201
202static __init char *get_last_crashkernel(char *cmdline,
203 const char *name,
204 const char *suffix)
205{
206 char *p = cmdline, *ck_cmdline = NULL;
207
208 /* find crashkernel and use the last one if there are more */
209 p = strstr(p, name);
210 while (p) {
211 char *end_p = strchr(p, ' ');
212 char *q;
213
214 if (!end_p)
215 end_p = p + strlen(p);
216
217 if (!suffix) {
218 int i;
219
220 /* skip the one with any known suffix */
221 for (i = 0; suffix_tbl[i]; i++) {
222 q = end_p - strlen(suffix_tbl[i]);
223 if (!strncmp(q, suffix_tbl[i],
224 strlen(suffix_tbl[i])))
225 goto next;
226 }
227 ck_cmdline = p;
228 } else {
229 q = end_p - strlen(suffix);
230 if (!strncmp(q, suffix, strlen(suffix)))
231 ck_cmdline = p;
232 }
233next:
234 p = strstr(p+1, name);
235 }
236
237 return ck_cmdline;
238}
239
240static int __init __parse_crashkernel(char *cmdline,
241 unsigned long long system_ram,
242 unsigned long long *crash_size,
243 unsigned long long *crash_base,
244 const char *name,
245 const char *suffix)
246{
247 char *first_colon, *first_space;
248 char *ck_cmdline;
249
250 BUG_ON(!crash_size || !crash_base);
251 *crash_size = 0;
252 *crash_base = 0;
253
254 ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
255 if (!ck_cmdline)
256 return -ENOENT;
257
258 ck_cmdline += strlen(name);
259
260 if (suffix)
261 return parse_crashkernel_suffix(ck_cmdline, crash_size,
262 suffix);
263 /*
264 * if the commandline contains a ':', then that's the extended
265 * syntax -- if not, it must be the classic syntax
266 */
267 first_colon = strchr(ck_cmdline, ':');
268 first_space = strchr(ck_cmdline, ' ');
269 if (first_colon && (!first_space || first_colon < first_space))
270 return parse_crashkernel_mem(ck_cmdline, system_ram,
271 crash_size, crash_base);
272
273 return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
274}
275
276/*
277 * That function is the entry point for command line parsing and should be
278 * called from the arch-specific code.
279 */
280int __init parse_crashkernel(char *cmdline,
281 unsigned long long system_ram,
282 unsigned long long *crash_size,
283 unsigned long long *crash_base)
284{
285 return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
286 "crashkernel=", NULL);
287}
288
289int __init parse_crashkernel_high(char *cmdline,
290 unsigned long long system_ram,
291 unsigned long long *crash_size,
292 unsigned long long *crash_base)
293{
294 return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
295 "crashkernel=", suffix_tbl[SUFFIX_HIGH]);
296}
297
298int __init parse_crashkernel_low(char *cmdline,
299 unsigned long long system_ram,
300 unsigned long long *crash_size,
301 unsigned long long *crash_base)
302{
303 return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
304 "crashkernel=", suffix_tbl[SUFFIX_LOW]);
305}
306
307/*
308 * Add a dummy early_param handler to mark crashkernel= as a known command line
309 * parameter and suppress incorrect warnings in init/main.c.
310 */
311static int __init parse_crashkernel_dummy(char *arg)
312{
313 return 0;
314}
315early_param("crashkernel", parse_crashkernel_dummy);
316
317Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
318 void *data, size_t data_len)
319{
320 struct elf_note *note = (struct elf_note *)buf;
321
322 note->n_namesz = strlen(name) + 1;
323 note->n_descsz = data_len;
324 note->n_type = type;
325 buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
326 memcpy(buf, name, note->n_namesz);
327 buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
328 memcpy(buf, data, data_len);
329 buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
330
331 return buf;
332}
333
334void final_note(Elf_Word *buf)
335{
336 memset(buf, 0, sizeof(struct elf_note));
337}
338
339static void update_vmcoreinfo_note(void)
340{
341 u32 *buf = vmcoreinfo_note;
342
343 if (!vmcoreinfo_size)
344 return;
345 buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
346 vmcoreinfo_size);
347 final_note(buf);
348}
349
350void crash_update_vmcoreinfo_safecopy(void *ptr)
351{
352 if (ptr)
353 memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
354
355 vmcoreinfo_data_safecopy = ptr;
356}
357
358void crash_save_vmcoreinfo(void)
359{
360 if (!vmcoreinfo_note)
361 return;
362
363 /* Use the safe copy to generate vmcoreinfo note if have */
364 if (vmcoreinfo_data_safecopy)
365 vmcoreinfo_data = vmcoreinfo_data_safecopy;
366
367 vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
368 update_vmcoreinfo_note();
369}
370
371void vmcoreinfo_append_str(const char *fmt, ...)
372{
373 va_list args;
374 char buf[0x50];
375 size_t r;
376
377 va_start(args, fmt);
378 r = vscnprintf(buf, sizeof(buf), fmt, args);
379 va_end(args);
380
381 r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);
382
383 memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
384
385 vmcoreinfo_size += r;
386
387 WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES,
388 "vmcoreinfo data exceeds allocated size, truncating");
389}
390
391/*
392 * provide an empty default implementation here -- architecture
393 * code may override this
394 */
395void __weak arch_crash_save_vmcoreinfo(void)
396{}
397
398phys_addr_t __weak paddr_vmcoreinfo_note(void)
399{
400 return __pa(vmcoreinfo_note);
401}
402EXPORT_SYMBOL(paddr_vmcoreinfo_note);
403
404static int __init crash_save_vmcoreinfo_init(void)
405{
406 vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
407 if (!vmcoreinfo_data) {
408 pr_warn("Memory allocation for vmcoreinfo_data failed\n");
409 return -ENOMEM;
410 }
411
412 vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
413 GFP_KERNEL | __GFP_ZERO);
414 if (!vmcoreinfo_note) {
415 free_page((unsigned long)vmcoreinfo_data);
416 vmcoreinfo_data = NULL;
417 pr_warn("Memory allocation for vmcoreinfo_note failed\n");
418 return -ENOMEM;
419 }
420
421 VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
422 VMCOREINFO_BUILD_ID();
423 VMCOREINFO_PAGESIZE(PAGE_SIZE);
424
425 VMCOREINFO_SYMBOL(init_uts_ns);
426 VMCOREINFO_OFFSET(uts_namespace, name);
427 VMCOREINFO_SYMBOL(node_online_map);
428#ifdef CONFIG_MMU
429 VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
430#endif
431 VMCOREINFO_SYMBOL(_stext);
432 VMCOREINFO_SYMBOL(vmap_area_list);
433
434#ifndef CONFIG_NUMA
435 VMCOREINFO_SYMBOL(mem_map);
436 VMCOREINFO_SYMBOL(contig_page_data);
437#endif
438#ifdef CONFIG_SPARSEMEM
439 VMCOREINFO_SYMBOL_ARRAY(mem_section);
440 VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
441 VMCOREINFO_STRUCT_SIZE(mem_section);
442 VMCOREINFO_OFFSET(mem_section, section_mem_map);
443 VMCOREINFO_NUMBER(SECTION_SIZE_BITS);
444 VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
445#endif
446 VMCOREINFO_STRUCT_SIZE(page);
447 VMCOREINFO_STRUCT_SIZE(pglist_data);
448 VMCOREINFO_STRUCT_SIZE(zone);
449 VMCOREINFO_STRUCT_SIZE(free_area);
450 VMCOREINFO_STRUCT_SIZE(list_head);
451 VMCOREINFO_SIZE(nodemask_t);
452 VMCOREINFO_OFFSET(page, flags);
453 VMCOREINFO_OFFSET(page, _refcount);
454 VMCOREINFO_OFFSET(page, mapping);
455 VMCOREINFO_OFFSET(page, lru);
456 VMCOREINFO_OFFSET(page, _mapcount);
457 VMCOREINFO_OFFSET(page, private);
458 VMCOREINFO_OFFSET(page, compound_dtor);
459 VMCOREINFO_OFFSET(page, compound_order);
460 VMCOREINFO_OFFSET(page, compound_head);
461 VMCOREINFO_OFFSET(pglist_data, node_zones);
462 VMCOREINFO_OFFSET(pglist_data, nr_zones);
463#ifdef CONFIG_FLATMEM
464 VMCOREINFO_OFFSET(pglist_data, node_mem_map);
465#endif
466 VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
467 VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
468 VMCOREINFO_OFFSET(pglist_data, node_id);
469 VMCOREINFO_OFFSET(zone, free_area);
470 VMCOREINFO_OFFSET(zone, vm_stat);
471 VMCOREINFO_OFFSET(zone, spanned_pages);
472 VMCOREINFO_OFFSET(free_area, free_list);
473 VMCOREINFO_OFFSET(list_head, next);
474 VMCOREINFO_OFFSET(list_head, prev);
475 VMCOREINFO_OFFSET(vmap_area, va_start);
476 VMCOREINFO_OFFSET(vmap_area, list);
477 VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
478 log_buf_vmcoreinfo_setup();
479 VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
480 VMCOREINFO_NUMBER(NR_FREE_PAGES);
481 VMCOREINFO_NUMBER(PG_lru);
482 VMCOREINFO_NUMBER(PG_private);
483 VMCOREINFO_NUMBER(PG_swapcache);
484 VMCOREINFO_NUMBER(PG_swapbacked);
485 VMCOREINFO_NUMBER(PG_slab);
486#ifdef CONFIG_MEMORY_FAILURE
487 VMCOREINFO_NUMBER(PG_hwpoison);
488#endif
489 VMCOREINFO_NUMBER(PG_head_mask);
490#define PAGE_BUDDY_MAPCOUNT_VALUE (~PG_buddy)
491 VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
492#ifdef CONFIG_HUGETLB_PAGE
493 VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR);
494#define PAGE_OFFLINE_MAPCOUNT_VALUE (~PG_offline)
495 VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
496#endif
497
498#ifdef CONFIG_KALLSYMS
499 VMCOREINFO_SYMBOL(kallsyms_names);
500 VMCOREINFO_SYMBOL(kallsyms_num_syms);
501 VMCOREINFO_SYMBOL(kallsyms_token_table);
502 VMCOREINFO_SYMBOL(kallsyms_token_index);
503#ifdef CONFIG_KALLSYMS_BASE_RELATIVE
504 VMCOREINFO_SYMBOL(kallsyms_offsets);
505 VMCOREINFO_SYMBOL(kallsyms_relative_base);
506#else
507 VMCOREINFO_SYMBOL(kallsyms_addresses);
508#endif /* CONFIG_KALLSYMS_BASE_RELATIVE */
509#endif /* CONFIG_KALLSYMS */
510
511 arch_crash_save_vmcoreinfo();
512 update_vmcoreinfo_note();
513
514 return 0;
515}
516
517subsys_initcall(crash_save_vmcoreinfo_init);
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/mm.h>
15#include <linux/cpuhotplug.h>
16#include <linux/memblock.h>
17#include <linux/kmemleak.h>
18#include <linux/crash_core.h>
19#include <linux/reboot.h>
20#include <linux/btf.h>
21#include <linux/objtool.h>
22
23#include <asm/page.h>
24#include <asm/sections.h>
25
26#include <crypto/sha1.h>
27
28#include "kallsyms_internal.h"
29#include "kexec_internal.h"
30
31/* Per cpu memory for storing cpu states in case of system crash. */
32note_buf_t __percpu *crash_notes;
33
34#ifdef CONFIG_CRASH_DUMP
35
36int kimage_crash_copy_vmcoreinfo(struct kimage *image)
37{
38 struct page *vmcoreinfo_page;
39 void *safecopy;
40
41 if (!IS_ENABLED(CONFIG_CRASH_DUMP))
42 return 0;
43 if (image->type != KEXEC_TYPE_CRASH)
44 return 0;
45
46 /*
47 * For kdump, allocate one vmcoreinfo safe copy from the
48 * crash memory. as we have arch_kexec_protect_crashkres()
49 * after kexec syscall, we naturally protect it from write
50 * (even read) access under kernel direct mapping. But on
51 * the other hand, we still need to operate it when crash
52 * happens to generate vmcoreinfo note, hereby we rely on
53 * vmap for this purpose.
54 */
55 vmcoreinfo_page = kimage_alloc_control_pages(image, 0);
56 if (!vmcoreinfo_page) {
57 pr_warn("Could not allocate vmcoreinfo buffer\n");
58 return -ENOMEM;
59 }
60 safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL);
61 if (!safecopy) {
62 pr_warn("Could not vmap vmcoreinfo buffer\n");
63 return -ENOMEM;
64 }
65
66 image->vmcoreinfo_data_copy = safecopy;
67 crash_update_vmcoreinfo_safecopy(safecopy);
68
69 return 0;
70}
71
72
73
74int kexec_should_crash(struct task_struct *p)
75{
76 /*
77 * If crash_kexec_post_notifiers is enabled, don't run
78 * crash_kexec() here yet, which must be run after panic
79 * notifiers in panic().
80 */
81 if (crash_kexec_post_notifiers)
82 return 0;
83 /*
84 * There are 4 panic() calls in make_task_dead() path, each of which
85 * corresponds to each of these 4 conditions.
86 */
87 if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
88 return 1;
89 return 0;
90}
91
92int kexec_crash_loaded(void)
93{
94 return !!kexec_crash_image;
95}
96EXPORT_SYMBOL_GPL(kexec_crash_loaded);
97
98/*
99 * No panic_cpu check version of crash_kexec(). This function is called
100 * only when panic_cpu holds the current CPU number; this is the only CPU
101 * which processes crash_kexec routines.
102 */
103void __noclone __crash_kexec(struct pt_regs *regs)
104{
105 /* Take the kexec_lock here to prevent sys_kexec_load
106 * running on one cpu from replacing the crash kernel
107 * we are using after a panic on a different cpu.
108 *
109 * If the crash kernel was not located in a fixed area
110 * of memory the xchg(&kexec_crash_image) would be
111 * sufficient. But since I reuse the memory...
112 */
113 if (kexec_trylock()) {
114 if (kexec_crash_image) {
115 struct pt_regs fixed_regs;
116
117 crash_setup_regs(&fixed_regs, regs);
118 crash_save_vmcoreinfo();
119 machine_crash_shutdown(&fixed_regs);
120 machine_kexec(kexec_crash_image);
121 }
122 kexec_unlock();
123 }
124}
125STACK_FRAME_NON_STANDARD(__crash_kexec);
126
127__bpf_kfunc void crash_kexec(struct pt_regs *regs)
128{
129 int old_cpu, this_cpu;
130
131 /*
132 * Only one CPU is allowed to execute the crash_kexec() code as with
133 * panic(). Otherwise parallel calls of panic() and crash_kexec()
134 * may stop each other. To exclude them, we use panic_cpu here too.
135 */
136 old_cpu = PANIC_CPU_INVALID;
137 this_cpu = raw_smp_processor_id();
138
139 if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) {
140 /* This is the 1st CPU which comes here, so go ahead. */
141 __crash_kexec(regs);
142
143 /*
144 * Reset panic_cpu to allow another panic()/crash_kexec()
145 * call.
146 */
147 atomic_set(&panic_cpu, PANIC_CPU_INVALID);
148 }
149}
150
151static inline resource_size_t crash_resource_size(const struct resource *res)
152{
153 return !res->end ? 0 : resource_size(res);
154}
155
156
157
158
159int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
160 void **addr, unsigned long *sz)
161{
162 Elf64_Ehdr *ehdr;
163 Elf64_Phdr *phdr;
164 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
165 unsigned char *buf;
166 unsigned int cpu, i;
167 unsigned long long notes_addr;
168 unsigned long mstart, mend;
169
170 /* extra phdr for vmcoreinfo ELF note */
171 nr_phdr = nr_cpus + 1;
172 nr_phdr += mem->nr_ranges;
173
174 /*
175 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
176 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
177 * I think this is required by tools like gdb. So same physical
178 * memory will be mapped in two ELF headers. One will contain kernel
179 * text virtual addresses and other will have __va(physical) addresses.
180 */
181
182 nr_phdr++;
183 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
184 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
185
186 buf = vzalloc(elf_sz);
187 if (!buf)
188 return -ENOMEM;
189
190 ehdr = (Elf64_Ehdr *)buf;
191 phdr = (Elf64_Phdr *)(ehdr + 1);
192 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
193 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
194 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
195 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
196 ehdr->e_ident[EI_OSABI] = ELF_OSABI;
197 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
198 ehdr->e_type = ET_CORE;
199 ehdr->e_machine = ELF_ARCH;
200 ehdr->e_version = EV_CURRENT;
201 ehdr->e_phoff = sizeof(Elf64_Ehdr);
202 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
203 ehdr->e_phentsize = sizeof(Elf64_Phdr);
204
205 /* Prepare one phdr of type PT_NOTE for each possible CPU */
206 for_each_possible_cpu(cpu) {
207 phdr->p_type = PT_NOTE;
208 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
209 phdr->p_offset = phdr->p_paddr = notes_addr;
210 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
211 (ehdr->e_phnum)++;
212 phdr++;
213 }
214
215 /* Prepare one PT_NOTE header for vmcoreinfo */
216 phdr->p_type = PT_NOTE;
217 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
218 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
219 (ehdr->e_phnum)++;
220 phdr++;
221
222 /* Prepare PT_LOAD type program header for kernel text region */
223 if (need_kernel_map) {
224 phdr->p_type = PT_LOAD;
225 phdr->p_flags = PF_R|PF_W|PF_X;
226 phdr->p_vaddr = (unsigned long) _text;
227 phdr->p_filesz = phdr->p_memsz = _end - _text;
228 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
229 ehdr->e_phnum++;
230 phdr++;
231 }
232
233 /* Go through all the ranges in mem->ranges[] and prepare phdr */
234 for (i = 0; i < mem->nr_ranges; i++) {
235 mstart = mem->ranges[i].start;
236 mend = mem->ranges[i].end;
237
238 phdr->p_type = PT_LOAD;
239 phdr->p_flags = PF_R|PF_W|PF_X;
240 phdr->p_offset = mstart;
241
242 phdr->p_paddr = mstart;
243 phdr->p_vaddr = (unsigned long) __va(mstart);
244 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
245 phdr->p_align = 0;
246 ehdr->e_phnum++;
247#ifdef CONFIG_KEXEC_FILE
248 kexec_dprintk("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
249 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
250 ehdr->e_phnum, phdr->p_offset);
251#endif
252 phdr++;
253 }
254
255 *addr = buf;
256 *sz = elf_sz;
257 return 0;
258}
259
260int crash_exclude_mem_range(struct crash_mem *mem,
261 unsigned long long mstart, unsigned long long mend)
262{
263 int i;
264 unsigned long long start, end, p_start, p_end;
265
266 for (i = 0; i < mem->nr_ranges; i++) {
267 start = mem->ranges[i].start;
268 end = mem->ranges[i].end;
269 p_start = mstart;
270 p_end = mend;
271
272 if (p_start > end)
273 continue;
274
275 /*
276 * Because the memory ranges in mem->ranges are stored in
277 * ascending order, when we detect `p_end < start`, we can
278 * immediately exit the for loop, as the subsequent memory
279 * ranges will definitely be outside the range we are looking
280 * for.
281 */
282 if (p_end < start)
283 break;
284
285 /* Truncate any area outside of range */
286 if (p_start < start)
287 p_start = start;
288 if (p_end > end)
289 p_end = end;
290
291 /* Found completely overlapping range */
292 if (p_start == start && p_end == end) {
293 memmove(&mem->ranges[i], &mem->ranges[i + 1],
294 (mem->nr_ranges - (i + 1)) * sizeof(mem->ranges[i]));
295 i--;
296 mem->nr_ranges--;
297 } else if (p_start > start && p_end < end) {
298 /* Split original range */
299 if (mem->nr_ranges >= mem->max_nr_ranges)
300 return -ENOMEM;
301
302 memmove(&mem->ranges[i + 2], &mem->ranges[i + 1],
303 (mem->nr_ranges - (i + 1)) * sizeof(mem->ranges[i]));
304
305 mem->ranges[i].end = p_start - 1;
306 mem->ranges[i + 1].start = p_end + 1;
307 mem->ranges[i + 1].end = end;
308
309 i++;
310 mem->nr_ranges++;
311 } else if (p_start != start)
312 mem->ranges[i].end = p_start - 1;
313 else
314 mem->ranges[i].start = p_end + 1;
315 }
316
317 return 0;
318}
319
320ssize_t crash_get_memory_size(void)
321{
322 ssize_t size = 0;
323
324 if (!kexec_trylock())
325 return -EBUSY;
326
327 size += crash_resource_size(&crashk_res);
328 size += crash_resource_size(&crashk_low_res);
329
330 kexec_unlock();
331 return size;
332}
333
334static int __crash_shrink_memory(struct resource *old_res,
335 unsigned long new_size)
336{
337 struct resource *ram_res;
338
339 ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
340 if (!ram_res)
341 return -ENOMEM;
342
343 ram_res->start = old_res->start + new_size;
344 ram_res->end = old_res->end;
345 ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
346 ram_res->name = "System RAM";
347
348 if (!new_size) {
349 release_resource(old_res);
350 old_res->start = 0;
351 old_res->end = 0;
352 } else {
353 crashk_res.end = ram_res->start - 1;
354 }
355
356 crash_free_reserved_phys_range(ram_res->start, ram_res->end);
357 insert_resource(&iomem_resource, ram_res);
358
359 return 0;
360}
361
362int crash_shrink_memory(unsigned long new_size)
363{
364 int ret = 0;
365 unsigned long old_size, low_size;
366
367 if (!kexec_trylock())
368 return -EBUSY;
369
370 if (kexec_crash_image) {
371 ret = -ENOENT;
372 goto unlock;
373 }
374
375 low_size = crash_resource_size(&crashk_low_res);
376 old_size = crash_resource_size(&crashk_res) + low_size;
377 new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
378 if (new_size >= old_size) {
379 ret = (new_size == old_size) ? 0 : -EINVAL;
380 goto unlock;
381 }
382
383 /*
384 * (low_size > new_size) implies that low_size is greater than zero.
385 * This also means that if low_size is zero, the else branch is taken.
386 *
387 * If low_size is greater than 0, (low_size > new_size) indicates that
388 * crashk_low_res also needs to be shrunken. Otherwise, only crashk_res
389 * needs to be shrunken.
390 */
391 if (low_size > new_size) {
392 ret = __crash_shrink_memory(&crashk_res, 0);
393 if (ret)
394 goto unlock;
395
396 ret = __crash_shrink_memory(&crashk_low_res, new_size);
397 } else {
398 ret = __crash_shrink_memory(&crashk_res, new_size - low_size);
399 }
400
401 /* Swap crashk_res and crashk_low_res if needed */
402 if (!crashk_res.end && crashk_low_res.end) {
403 crashk_res.start = crashk_low_res.start;
404 crashk_res.end = crashk_low_res.end;
405 release_resource(&crashk_low_res);
406 crashk_low_res.start = 0;
407 crashk_low_res.end = 0;
408 insert_resource(&iomem_resource, &crashk_res);
409 }
410
411unlock:
412 kexec_unlock();
413 return ret;
414}
415
416void crash_save_cpu(struct pt_regs *regs, int cpu)
417{
418 struct elf_prstatus prstatus;
419 u32 *buf;
420
421 if ((cpu < 0) || (cpu >= nr_cpu_ids))
422 return;
423
424 /* Using ELF notes here is opportunistic.
425 * I need a well defined structure format
426 * for the data I pass, and I need tags
427 * on the data to indicate what information I have
428 * squirrelled away. ELF notes happen to provide
429 * all of that, so there is no need to invent something new.
430 */
431 buf = (u32 *)per_cpu_ptr(crash_notes, cpu);
432 if (!buf)
433 return;
434 memset(&prstatus, 0, sizeof(prstatus));
435 prstatus.common.pr_pid = current->pid;
436 elf_core_copy_regs(&prstatus.pr_reg, regs);
437 buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
438 &prstatus, sizeof(prstatus));
439 final_note(buf);
440}
441
442
443
444static int __init crash_notes_memory_init(void)
445{
446 /* Allocate memory for saving cpu registers. */
447 size_t size, align;
448
449 /*
450 * crash_notes could be allocated across 2 vmalloc pages when percpu
451 * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
452 * pages are also on 2 continuous physical pages. In this case the
453 * 2nd part of crash_notes in 2nd page could be lost since only the
454 * starting address and size of crash_notes are exported through sysfs.
455 * Here round up the size of crash_notes to the nearest power of two
456 * and pass it to __alloc_percpu as align value. This can make sure
457 * crash_notes is allocated inside one physical page.
458 */
459 size = sizeof(note_buf_t);
460 align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
461
462 /*
463 * Break compile if size is bigger than PAGE_SIZE since crash_notes
464 * definitely will be in 2 pages with that.
465 */
466 BUILD_BUG_ON(size > PAGE_SIZE);
467
468 crash_notes = __alloc_percpu(size, align);
469 if (!crash_notes) {
470 pr_warn("Memory allocation for saving cpu register states failed\n");
471 return -ENOMEM;
472 }
473 return 0;
474}
475subsys_initcall(crash_notes_memory_init);
476
477#endif /*CONFIG_CRASH_DUMP*/
478
479#ifdef CONFIG_CRASH_HOTPLUG
480#undef pr_fmt
481#define pr_fmt(fmt) "crash hp: " fmt
482
483/*
484 * Different than kexec/kdump loading/unloading/jumping/shrinking which
485 * usually rarely happen, there will be many crash hotplug events notified
486 * during one short period, e.g one memory board is hot added and memory
487 * regions are online. So mutex lock __crash_hotplug_lock is used to
488 * serialize the crash hotplug handling specifically.
489 */
490static DEFINE_MUTEX(__crash_hotplug_lock);
491#define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock)
492#define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock)
493
494/*
495 * This routine utilized when the crash_hotplug sysfs node is read.
496 * It reflects the kernel's ability/permission to update the crash
497 * elfcorehdr directly.
498 */
499int crash_check_update_elfcorehdr(void)
500{
501 int rc = 0;
502
503 crash_hotplug_lock();
504 /* Obtain lock while reading crash information */
505 if (!kexec_trylock()) {
506 pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
507 crash_hotplug_unlock();
508 return 0;
509 }
510 if (kexec_crash_image) {
511 if (kexec_crash_image->file_mode)
512 rc = 1;
513 else
514 rc = kexec_crash_image->update_elfcorehdr;
515 }
516 /* Release lock now that update complete */
517 kexec_unlock();
518 crash_hotplug_unlock();
519
520 return rc;
521}
522
523/*
524 * To accurately reflect hot un/plug changes of cpu and memory resources
525 * (including onling and offlining of those resources), the elfcorehdr
526 * (which is passed to the crash kernel via the elfcorehdr= parameter)
527 * must be updated with the new list of CPUs and memories.
528 *
529 * In order to make changes to elfcorehdr, two conditions are needed:
530 * First, the segment containing the elfcorehdr must be large enough
531 * to permit a growing number of resources; the elfcorehdr memory size
532 * is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES.
533 * Second, purgatory must explicitly exclude the elfcorehdr from the
534 * list of segments it checks (since the elfcorehdr changes and thus
535 * would require an update to purgatory itself to update the digest).
536 */
537static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
538{
539 struct kimage *image;
540
541 crash_hotplug_lock();
542 /* Obtain lock while changing crash information */
543 if (!kexec_trylock()) {
544 pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
545 crash_hotplug_unlock();
546 return;
547 }
548
549 /* Check kdump is not loaded */
550 if (!kexec_crash_image)
551 goto out;
552
553 image = kexec_crash_image;
554
555 /* Check that updating elfcorehdr is permitted */
556 if (!(image->file_mode || image->update_elfcorehdr))
557 goto out;
558
559 if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
560 hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
561 pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
562 else
563 pr_debug("hp_action %u\n", hp_action);
564
565 /*
566 * The elfcorehdr_index is set to -1 when the struct kimage
567 * is allocated. Find the segment containing the elfcorehdr,
568 * if not already found.
569 */
570 if (image->elfcorehdr_index < 0) {
571 unsigned long mem;
572 unsigned char *ptr;
573 unsigned int n;
574
575 for (n = 0; n < image->nr_segments; n++) {
576 mem = image->segment[n].mem;
577 ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
578 if (ptr) {
579 /* The segment containing elfcorehdr */
580 if (memcmp(ptr, ELFMAG, SELFMAG) == 0)
581 image->elfcorehdr_index = (int)n;
582 kunmap_local(ptr);
583 }
584 }
585 }
586
587 if (image->elfcorehdr_index < 0) {
588 pr_err("unable to locate elfcorehdr segment");
589 goto out;
590 }
591
592 /* Needed in order for the segments to be updated */
593 arch_kexec_unprotect_crashkres();
594
595 /* Differentiate between normal load and hotplug update */
596 image->hp_action = hp_action;
597
598 /* Now invoke arch-specific update handler */
599 arch_crash_handle_hotplug_event(image);
600
601 /* No longer handling a hotplug event */
602 image->hp_action = KEXEC_CRASH_HP_NONE;
603 image->elfcorehdr_updated = true;
604
605 /* Change back to read-only */
606 arch_kexec_protect_crashkres();
607
608 /* Errors in the callback is not a reason to rollback state */
609out:
610 /* Release lock now that update complete */
611 kexec_unlock();
612 crash_hotplug_unlock();
613}
614
615static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
616{
617 switch (val) {
618 case MEM_ONLINE:
619 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
620 KEXEC_CRASH_HP_INVALID_CPU);
621 break;
622
623 case MEM_OFFLINE:
624 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
625 KEXEC_CRASH_HP_INVALID_CPU);
626 break;
627 }
628 return NOTIFY_OK;
629}
630
631static struct notifier_block crash_memhp_nb = {
632 .notifier_call = crash_memhp_notifier,
633 .priority = 0
634};
635
636static int crash_cpuhp_online(unsigned int cpu)
637{
638 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
639 return 0;
640}
641
642static int crash_cpuhp_offline(unsigned int cpu)
643{
644 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
645 return 0;
646}
647
648static int __init crash_hotplug_init(void)
649{
650 int result = 0;
651
652 if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
653 register_memory_notifier(&crash_memhp_nb);
654
655 if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
656 result = cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN,
657 "crash/cpuhp", crash_cpuhp_online, crash_cpuhp_offline);
658 }
659
660 return result;
661}
662
663subsys_initcall(crash_hotplug_init);
664#endif