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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9 #include <linux/buildid.h>
10 #include <linux/init.h>
11 #include <linux/utsname.h>
12 #include <linux/vmalloc.h>
13 #include <linux/sizes.h>
14 #include <linux/kexec.h>
15 #include <linux/memory.h>
16 #include <linux/mm.h>
17 #include <linux/cpuhotplug.h>
18 #include <linux/memblock.h>
19 #include <linux/kmemleak.h>
20 #include <linux/crash_core.h>
21 #include <linux/reboot.h>
22 #include <linux/btf.h>
23 #include <linux/objtool.h>
24 #include <linux/delay.h>
25 #include <linux/panic.h>
26
27 #include <asm/page.h>
28 #include <asm/sections.h>
29
30 #include "kallsyms_internal.h"
31 #include "kexec_internal.h"
32
33 /* Per cpu memory for storing cpu states in case of system crash. */
34 note_buf_t __percpu *crash_notes;
35
36 /* time to wait for possible DMA to finish before starting the kdump kernel
37 * when a CMA reservation is used
38 */
39 #define CMA_DMA_TIMEOUT_SEC 10
40
41 #ifdef CONFIG_CRASH_DUMP
42
kimage_crash_copy_vmcoreinfo(struct kimage * image)43 int kimage_crash_copy_vmcoreinfo(struct kimage *image)
44 {
45 struct page *vmcoreinfo_base;
46 struct page *vmcoreinfo_pages[DIV_ROUND_UP(VMCOREINFO_BYTES, PAGE_SIZE)];
47 unsigned int order, nr_pages;
48 int i;
49 void *safecopy;
50
51 nr_pages = DIV_ROUND_UP(VMCOREINFO_BYTES, PAGE_SIZE);
52 order = get_order(VMCOREINFO_BYTES);
53
54 if (!IS_ENABLED(CONFIG_CRASH_DUMP))
55 return 0;
56 if (image->type != KEXEC_TYPE_CRASH)
57 return 0;
58
59 /*
60 * For kdump, allocate one vmcoreinfo safe copy from the
61 * crash memory. as we have arch_kexec_protect_crashkres()
62 * after kexec syscall, we naturally protect it from write
63 * (even read) access under kernel direct mapping. But on
64 * the other hand, we still need to operate it when crash
65 * happens to generate vmcoreinfo note, hereby we rely on
66 * vmap for this purpose.
67 */
68 vmcoreinfo_base = kimage_alloc_control_pages(image, order);
69 if (!vmcoreinfo_base) {
70 pr_warn("Could not allocate vmcoreinfo buffer\n");
71 return -ENOMEM;
72 }
73 for (i = 0; i < nr_pages; i++)
74 vmcoreinfo_pages[i] = vmcoreinfo_base + i;
75
76 safecopy = vmap(vmcoreinfo_pages, nr_pages, VM_MAP, PAGE_KERNEL);
77 if (!safecopy) {
78 pr_warn("Could not vmap vmcoreinfo buffer\n");
79 return -ENOMEM;
80 }
81
82 image->vmcoreinfo_data_copy = safecopy;
83 crash_update_vmcoreinfo_safecopy(safecopy);
84
85 return 0;
86 }
87
88
89
kexec_should_crash(struct task_struct * p)90 int kexec_should_crash(struct task_struct *p)
91 {
92 /*
93 * If crash_kexec_post_notifiers is enabled, don't run
94 * crash_kexec() here yet, which must be run after panic
95 * notifiers in panic().
96 */
97 if (crash_kexec_post_notifiers)
98 return 0;
99 /*
100 * There are 4 panic() calls in make_task_dead() path, each of which
101 * corresponds to each of these 4 conditions.
102 */
103 if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
104 return 1;
105 return 0;
106 }
107
kexec_crash_loaded(void)108 int kexec_crash_loaded(void)
109 {
110 return !!kexec_crash_image;
111 }
112 EXPORT_SYMBOL_GPL(kexec_crash_loaded);
113
crash_cma_clear_pending_dma(void)114 static void crash_cma_clear_pending_dma(void)
115 {
116 if (!crashk_cma_cnt)
117 return;
118
119 mdelay(CMA_DMA_TIMEOUT_SEC * 1000);
120 }
121
122 /*
123 * No panic_cpu check version of crash_kexec(). This function is called
124 * only when panic_cpu holds the current CPU number; this is the only CPU
125 * which processes crash_kexec routines.
126 */
__crash_kexec(struct pt_regs * regs)127 void __noclone __crash_kexec(struct pt_regs *regs)
128 {
129 /* Take the kexec_lock here to prevent sys_kexec_load
130 * running on one cpu from replacing the crash kernel
131 * we are using after a panic on a different cpu.
132 *
133 * If the crash kernel was not located in a fixed area
134 * of memory the xchg(&kexec_crash_image) would be
135 * sufficient. But since I reuse the memory...
136 */
137 if (kexec_trylock()) {
138 if (kexec_crash_image) {
139 struct pt_regs fixed_regs;
140
141 crash_setup_regs(&fixed_regs, regs);
142 crash_save_vmcoreinfo();
143 machine_crash_shutdown(&fixed_regs);
144 crash_cma_clear_pending_dma();
145 machine_kexec(kexec_crash_image);
146 }
147 kexec_unlock();
148 }
149 }
150 STACK_FRAME_NON_STANDARD(__crash_kexec);
151
crash_kexec(struct pt_regs * regs)152 __bpf_kfunc void crash_kexec(struct pt_regs *regs)
153 {
154 if (panic_try_start()) {
155 /* This is the 1st CPU which comes here, so go ahead. */
156 __crash_kexec(regs);
157
158 /*
159 * Reset panic_cpu to allow another panic()/crash_kexec()
160 * call.
161 */
162 panic_reset();
163 }
164 }
165
crash_resource_size(const struct resource * res)166 static inline resource_size_t crash_resource_size(const struct resource *res)
167 {
168 return !res->end ? 0 : resource_size(res);
169 }
170
171
172
173
crash_prepare_elf64_headers(struct crash_mem * mem,int need_kernel_map,void ** addr,unsigned long * sz)174 int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
175 void **addr, unsigned long *sz)
176 {
177 Elf64_Ehdr *ehdr;
178 Elf64_Phdr *phdr;
179 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
180 unsigned char *buf;
181 unsigned int cpu, i;
182 unsigned long long notes_addr;
183 unsigned long mstart, mend;
184
185 /* extra phdr for vmcoreinfo ELF note */
186 nr_phdr = nr_cpus + 1;
187 nr_phdr += mem->nr_ranges;
188
189 /*
190 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
191 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
192 * I think this is required by tools like gdb. So same physical
193 * memory will be mapped in two ELF headers. One will contain kernel
194 * text virtual addresses and other will have __va(physical) addresses.
195 */
196
197 nr_phdr++;
198 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
199 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
200
201 buf = vzalloc(elf_sz);
202 if (!buf)
203 return -ENOMEM;
204
205 ehdr = (Elf64_Ehdr *)buf;
206 phdr = (Elf64_Phdr *)(ehdr + 1);
207 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
208 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
209 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
210 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
211 ehdr->e_ident[EI_OSABI] = ELF_OSABI;
212 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
213 ehdr->e_type = ET_CORE;
214 ehdr->e_machine = ELF_ARCH;
215 ehdr->e_version = EV_CURRENT;
216 ehdr->e_phoff = sizeof(Elf64_Ehdr);
217 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
218 ehdr->e_phentsize = sizeof(Elf64_Phdr);
219
220 /* Prepare one phdr of type PT_NOTE for each possible CPU */
221 for_each_possible_cpu(cpu) {
222 phdr->p_type = PT_NOTE;
223 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
224 phdr->p_offset = phdr->p_paddr = notes_addr;
225 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
226 (ehdr->e_phnum)++;
227 phdr++;
228 }
229
230 /* Prepare one PT_NOTE header for vmcoreinfo */
231 phdr->p_type = PT_NOTE;
232 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
233 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
234 (ehdr->e_phnum)++;
235 phdr++;
236
237 /* Prepare PT_LOAD type program header for kernel text region */
238 if (need_kernel_map) {
239 phdr->p_type = PT_LOAD;
240 phdr->p_flags = PF_R|PF_W|PF_X;
241 phdr->p_vaddr = (unsigned long) _text;
242 phdr->p_filesz = phdr->p_memsz = _end - _text;
243 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
244 ehdr->e_phnum++;
245 phdr++;
246 }
247
248 /* Go through all the ranges in mem->ranges[] and prepare phdr */
249 for (i = 0; i < mem->nr_ranges; i++) {
250 mstart = mem->ranges[i].start;
251 mend = mem->ranges[i].end;
252
253 phdr->p_type = PT_LOAD;
254 phdr->p_flags = PF_R|PF_W|PF_X;
255 phdr->p_offset = mstart;
256
257 phdr->p_paddr = mstart;
258 phdr->p_vaddr = (unsigned long) __va(mstart);
259 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
260 phdr->p_align = 0;
261 ehdr->e_phnum++;
262 #ifdef CONFIG_KEXEC_FILE
263 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",
264 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
265 ehdr->e_phnum, phdr->p_offset);
266 #endif
267 phdr++;
268 }
269
270 *addr = buf;
271 *sz = elf_sz;
272 return 0;
273 }
274
275 /**
276 * crash_exclude_mem_range - exclude a mem range for existing ranges
277 * @mem: mem->range contains an array of ranges sorted in ascending order
278 * @mstart: the start of to-be-excluded range
279 * @mend: the start of to-be-excluded range
280 *
281 * If you are unsure if a range split will happen, to avoid function call
282 * failure because of -ENOMEM, always make sure
283 * mem->max_nr_ranges == mem->nr_ranges + 1
284 * before calling the function each time.
285 *
286 * returns 0 if a memory range is excluded successfully
287 * return -ENOMEM if mem->ranges doesn't have space to hold split ranges
288 */
crash_exclude_mem_range(struct crash_mem * mem,unsigned long long mstart,unsigned long long mend)289 int crash_exclude_mem_range(struct crash_mem *mem,
290 unsigned long long mstart, unsigned long long mend)
291 {
292 int i;
293 unsigned long long start, end, p_start, p_end;
294
295 for (i = 0; i < mem->nr_ranges; i++) {
296 start = mem->ranges[i].start;
297 end = mem->ranges[i].end;
298 p_start = mstart;
299 p_end = mend;
300
301 if (p_start > end)
302 continue;
303
304 /*
305 * Because the memory ranges in mem->ranges are stored in
306 * ascending order, when we detect `p_end < start`, we can
307 * immediately exit the for loop, as the subsequent memory
308 * ranges will definitely be outside the range we are looking
309 * for.
310 */
311 if (p_end < start)
312 break;
313
314 /* Truncate any area outside of range */
315 if (p_start < start)
316 p_start = start;
317 if (p_end > end)
318 p_end = end;
319
320 /* Found completely overlapping range */
321 if (p_start == start && p_end == end) {
322 memmove(&mem->ranges[i], &mem->ranges[i + 1],
323 (mem->nr_ranges - (i + 1)) * sizeof(mem->ranges[i]));
324 i--;
325 mem->nr_ranges--;
326 } else if (p_start > start && p_end < end) {
327 /* Split original range */
328 if (mem->nr_ranges >= mem->max_nr_ranges)
329 return -ENOMEM;
330
331 memmove(&mem->ranges[i + 2], &mem->ranges[i + 1],
332 (mem->nr_ranges - (i + 1)) * sizeof(mem->ranges[i]));
333
334 mem->ranges[i].end = p_start - 1;
335 mem->ranges[i + 1].start = p_end + 1;
336 mem->ranges[i + 1].end = end;
337
338 i++;
339 mem->nr_ranges++;
340 } else if (p_start != start)
341 mem->ranges[i].end = p_start - 1;
342 else
343 mem->ranges[i].start = p_end + 1;
344 }
345
346 return 0;
347 }
348 EXPORT_SYMBOL_GPL(crash_exclude_mem_range);
349
crash_get_memory_size(void)350 ssize_t crash_get_memory_size(void)
351 {
352 ssize_t size = 0;
353
354 if (!kexec_trylock())
355 return -EBUSY;
356
357 size += crash_resource_size(&crashk_res);
358 size += crash_resource_size(&crashk_low_res);
359
360 kexec_unlock();
361 return size;
362 }
363
__crash_shrink_memory(struct resource * old_res,unsigned long new_size)364 static int __crash_shrink_memory(struct resource *old_res,
365 unsigned long new_size)
366 {
367 struct resource *ram_res;
368
369 ram_res = kzalloc_obj(*ram_res);
370 if (!ram_res)
371 return -ENOMEM;
372
373 ram_res->start = old_res->start + new_size;
374 ram_res->end = old_res->end;
375 ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
376 ram_res->name = "System RAM";
377
378 if (!new_size) {
379 release_resource(old_res);
380 old_res->start = 0;
381 old_res->end = 0;
382 } else {
383 old_res->end = ram_res->start - 1;
384 }
385
386 crash_free_reserved_phys_range(ram_res->start, ram_res->end);
387 insert_resource(&iomem_resource, ram_res);
388
389 return 0;
390 }
391
crash_shrink_memory(unsigned long new_size)392 int crash_shrink_memory(unsigned long new_size)
393 {
394 int ret = 0;
395 unsigned long old_size, low_size;
396
397 if (!kexec_trylock())
398 return -EBUSY;
399
400 if (kexec_crash_image) {
401 ret = -ENOENT;
402 goto unlock;
403 }
404
405 low_size = crash_resource_size(&crashk_low_res);
406 old_size = crash_resource_size(&crashk_res) + low_size;
407 new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
408 if (new_size >= old_size) {
409 ret = (new_size == old_size) ? 0 : -EINVAL;
410 goto unlock;
411 }
412
413 /*
414 * (low_size > new_size) implies that low_size is greater than zero.
415 * This also means that if low_size is zero, the else branch is taken.
416 *
417 * If low_size is greater than 0, (low_size > new_size) indicates that
418 * crashk_low_res also needs to be shrunken. Otherwise, only crashk_res
419 * needs to be shrunken.
420 */
421 if (low_size > new_size) {
422 ret = __crash_shrink_memory(&crashk_res, 0);
423 if (ret)
424 goto unlock;
425
426 ret = __crash_shrink_memory(&crashk_low_res, new_size);
427 } else {
428 ret = __crash_shrink_memory(&crashk_res, new_size - low_size);
429 }
430
431 /* Swap crashk_res and crashk_low_res if needed */
432 if (!crashk_res.end && crashk_low_res.end) {
433 crashk_res.start = crashk_low_res.start;
434 crashk_res.end = crashk_low_res.end;
435 release_resource(&crashk_low_res);
436 crashk_low_res.start = 0;
437 crashk_low_res.end = 0;
438 insert_resource(&iomem_resource, &crashk_res);
439 }
440
441 unlock:
442 kexec_unlock();
443 return ret;
444 }
445
crash_save_cpu(struct pt_regs * regs,int cpu)446 void crash_save_cpu(struct pt_regs *regs, int cpu)
447 {
448 struct elf_prstatus prstatus;
449 u32 *buf;
450
451 if ((cpu < 0) || (cpu >= nr_cpu_ids))
452 return;
453
454 /* Using ELF notes here is opportunistic.
455 * I need a well defined structure format
456 * for the data I pass, and I need tags
457 * on the data to indicate what information I have
458 * squirrelled away. ELF notes happen to provide
459 * all of that, so there is no need to invent something new.
460 */
461 buf = (u32 *)per_cpu_ptr(crash_notes, cpu);
462 if (!buf)
463 return;
464 memset(&prstatus, 0, sizeof(prstatus));
465 prstatus.common.pr_pid = current->pid;
466 elf_core_copy_regs(&prstatus.pr_reg, regs);
467 buf = append_elf_note(buf, NN_PRSTATUS, NT_PRSTATUS,
468 &prstatus, sizeof(prstatus));
469 final_note(buf);
470 }
471
472
473
crash_notes_memory_init(void)474 static int __init crash_notes_memory_init(void)
475 {
476 /* Allocate memory for saving cpu registers. */
477 size_t size, align;
478
479 /*
480 * crash_notes could be allocated across 2 vmalloc pages when percpu
481 * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
482 * pages are also on 2 continuous physical pages. In this case the
483 * 2nd part of crash_notes in 2nd page could be lost since only the
484 * starting address and size of crash_notes are exported through sysfs.
485 * Here round up the size of crash_notes to the nearest power of two
486 * and pass it to __alloc_percpu as align value. This can make sure
487 * crash_notes is allocated inside one physical page.
488 */
489 size = sizeof(note_buf_t);
490 align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
491
492 /*
493 * Break compile if size is bigger than PAGE_SIZE since crash_notes
494 * definitely will be in 2 pages with that.
495 */
496 BUILD_BUG_ON(size > PAGE_SIZE);
497
498 crash_notes = __alloc_percpu(size, align);
499 if (!crash_notes) {
500 pr_warn("Memory allocation for saving cpu register states failed\n");
501 return -ENOMEM;
502 }
503 return 0;
504 }
505 subsys_initcall(crash_notes_memory_init);
506
507 #endif /*CONFIG_CRASH_DUMP*/
508
509 #ifdef CONFIG_CRASH_HOTPLUG
510 #undef pr_fmt
511 #define pr_fmt(fmt) "crash hp: " fmt
512
513 /*
514 * Different than kexec/kdump loading/unloading/jumping/shrinking which
515 * usually rarely happen, there will be many crash hotplug events notified
516 * during one short period, e.g one memory board is hot added and memory
517 * regions are online. So mutex lock __crash_hotplug_lock is used to
518 * serialize the crash hotplug handling specifically.
519 */
520 static DEFINE_MUTEX(__crash_hotplug_lock);
521 #define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock)
522 #define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock)
523
524 /*
525 * This routine utilized when the crash_hotplug sysfs node is read.
526 * It reflects the kernel's ability/permission to update the kdump
527 * image directly.
528 */
crash_check_hotplug_support(void)529 int crash_check_hotplug_support(void)
530 {
531 int rc = 0;
532
533 crash_hotplug_lock();
534 /* Obtain lock while reading crash information */
535 if (!kexec_trylock()) {
536 if (!kexec_in_progress)
537 pr_info("kexec_trylock() failed, kdump image may be inaccurate\n");
538 crash_hotplug_unlock();
539 return 0;
540 }
541 if (kexec_crash_image) {
542 rc = kexec_crash_image->hotplug_support;
543 }
544 /* Release lock now that update complete */
545 kexec_unlock();
546 crash_hotplug_unlock();
547
548 return rc;
549 }
550
551 /*
552 * To accurately reflect hot un/plug changes of CPU and Memory resources
553 * (including onling and offlining of those resources), the relevant
554 * kexec segments must be updated with latest CPU and Memory resources.
555 *
556 * Architectures must ensure two things for all segments that need
557 * updating during hotplug events:
558 *
559 * 1. Segments must be large enough to accommodate a growing number of
560 * resources.
561 * 2. Exclude the segments from SHA verification.
562 *
563 * For example, on most architectures, the elfcorehdr (which is passed
564 * to the crash kernel via the elfcorehdr= parameter) must include the
565 * new list of CPUs and memory. To make changes to the elfcorehdr, it
566 * should be large enough to permit a growing number of CPU and Memory
567 * resources. One can estimate the elfcorehdr memory size based on
568 * NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES. The elfcorehdr is
569 * excluded from SHA verification by default if the architecture
570 * supports crash hotplug.
571 */
crash_handle_hotplug_event(unsigned int hp_action,unsigned int cpu,void * arg)572 static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, void *arg)
573 {
574 struct kimage *image;
575
576 crash_hotplug_lock();
577 /* Obtain lock while changing crash information */
578 if (!kexec_trylock()) {
579 if (!kexec_in_progress)
580 pr_info("kexec_trylock() failed, kdump image may be inaccurate\n");
581 crash_hotplug_unlock();
582 return;
583 }
584
585 /* Check kdump is not loaded */
586 if (!kexec_crash_image)
587 goto out;
588
589 image = kexec_crash_image;
590
591 /* Check that kexec segments update is permitted */
592 if (!image->hotplug_support)
593 goto out;
594
595 if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
596 hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
597 pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
598 else
599 pr_debug("hp_action %u\n", hp_action);
600
601 /*
602 * The elfcorehdr_index is set to -1 when the struct kimage
603 * is allocated. Find the segment containing the elfcorehdr,
604 * if not already found.
605 */
606 if (image->elfcorehdr_index < 0) {
607 unsigned long mem;
608 unsigned char *ptr;
609 unsigned int n;
610
611 for (n = 0; n < image->nr_segments; n++) {
612 mem = image->segment[n].mem;
613 ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
614 if (ptr) {
615 /* The segment containing elfcorehdr */
616 if (memcmp(ptr, ELFMAG, SELFMAG) == 0)
617 image->elfcorehdr_index = (int)n;
618 kunmap_local(ptr);
619 }
620 }
621 }
622
623 if (image->elfcorehdr_index < 0) {
624 pr_err("unable to locate elfcorehdr segment");
625 goto out;
626 }
627
628 /* Needed in order for the segments to be updated */
629 arch_kexec_unprotect_crashkres();
630
631 /* Differentiate between normal load and hotplug update */
632 image->hp_action = hp_action;
633
634 /* Now invoke arch-specific update handler */
635 arch_crash_handle_hotplug_event(image, arg);
636
637 /* No longer handling a hotplug event */
638 image->hp_action = KEXEC_CRASH_HP_NONE;
639 image->elfcorehdr_updated = true;
640
641 /* Change back to read-only */
642 arch_kexec_protect_crashkres();
643
644 /* Errors in the callback is not a reason to rollback state */
645 out:
646 /* Release lock now that update complete */
647 kexec_unlock();
648 crash_hotplug_unlock();
649 }
650
crash_memhp_notifier(struct notifier_block * nb,unsigned long val,void * arg)651 static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *arg)
652 {
653 switch (val) {
654 case MEM_ONLINE:
655 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
656 KEXEC_CRASH_HP_INVALID_CPU, arg);
657 break;
658
659 case MEM_OFFLINE:
660 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
661 KEXEC_CRASH_HP_INVALID_CPU, arg);
662 break;
663 }
664 return NOTIFY_OK;
665 }
666
667 static struct notifier_block crash_memhp_nb = {
668 .notifier_call = crash_memhp_notifier,
669 .priority = 0
670 };
671
crash_cpuhp_online(unsigned int cpu)672 static int crash_cpuhp_online(unsigned int cpu)
673 {
674 crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu, NULL);
675 return 0;
676 }
677
crash_cpuhp_offline(unsigned int cpu)678 static int crash_cpuhp_offline(unsigned int cpu)
679 {
680 crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu, NULL);
681 return 0;
682 }
683
crash_hotplug_init(void)684 static int __init crash_hotplug_init(void)
685 {
686 int result = 0;
687
688 if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
689 register_memory_notifier(&crash_memhp_nb);
690
691 if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
692 result = cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN,
693 "crash/cpuhp", crash_cpuhp_online, crash_cpuhp_offline);
694 }
695
696 return result;
697 }
698
699 subsys_initcall(crash_hotplug_init);
700 #endif
701