devcgroup: always show positive major/minor num
[linux-2.6/kmemtrace.git] / fs / proc / vmcore.c
blob9ac0f5e064e09e99f58b428e933b2903a893a5b9
1 /*
2 * fs/proc/vmcore.c Interface for accessing the crash
3 * dump from the system's previous life.
4 * Heavily borrowed from fs/proc/kcore.c
5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
6 * Copyright (C) IBM Corporation, 2004. All rights reserved
8 */
10 #include <linux/mm.h>
11 #include <linux/proc_fs.h>
12 #include <linux/user.h>
13 #include <linux/elf.h>
14 #include <linux/elfcore.h>
15 #include <linux/highmem.h>
16 #include <linux/bootmem.h>
17 #include <linux/init.h>
18 #include <linux/crash_dump.h>
19 #include <linux/list.h>
20 #include <asm/uaccess.h>
21 #include <asm/io.h>
23 /* List representing chunks of contiguous memory areas and their offsets in
24 * vmcore file.
26 static LIST_HEAD(vmcore_list);
28 /* Stores the pointer to the buffer containing kernel elf core headers. */
29 static char *elfcorebuf;
30 static size_t elfcorebuf_sz;
32 /* Total size of vmcore file. */
33 static u64 vmcore_size;
35 /* Stores the physical address of elf header of crash image. */
36 unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
38 struct proc_dir_entry *proc_vmcore = NULL;
40 /* Reads a page from the oldmem device from given offset. */
41 static ssize_t read_from_oldmem(char *buf, size_t count,
42 u64 *ppos, int userbuf)
44 unsigned long pfn, offset;
45 size_t nr_bytes;
46 ssize_t read = 0, tmp;
48 if (!count)
49 return 0;
51 offset = (unsigned long)(*ppos % PAGE_SIZE);
52 pfn = (unsigned long)(*ppos / PAGE_SIZE);
53 if (pfn > saved_max_pfn)
54 return -EINVAL;
56 do {
57 if (count > (PAGE_SIZE - offset))
58 nr_bytes = PAGE_SIZE - offset;
59 else
60 nr_bytes = count;
62 tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf);
63 if (tmp < 0)
64 return tmp;
65 *ppos += nr_bytes;
66 count -= nr_bytes;
67 buf += nr_bytes;
68 read += nr_bytes;
69 ++pfn;
70 offset = 0;
71 } while (count);
73 return read;
76 /* Maps vmcore file offset to respective physical address in memroy. */
77 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
78 struct vmcore **m_ptr)
80 struct vmcore *m;
81 u64 paddr;
83 list_for_each_entry(m, vc_list, list) {
84 u64 start, end;
85 start = m->offset;
86 end = m->offset + m->size - 1;
87 if (offset >= start && offset <= end) {
88 paddr = m->paddr + offset - start;
89 *m_ptr = m;
90 return paddr;
93 *m_ptr = NULL;
94 return 0;
97 /* Read from the ELF header and then the crash dump. On error, negative value is
98 * returned otherwise number of bytes read are returned.
100 static ssize_t read_vmcore(struct file *file, char __user *buffer,
101 size_t buflen, loff_t *fpos)
103 ssize_t acc = 0, tmp;
104 size_t tsz;
105 u64 start, nr_bytes;
106 struct vmcore *curr_m = NULL;
108 if (buflen == 0 || *fpos >= vmcore_size)
109 return 0;
111 /* trim buflen to not go beyond EOF */
112 if (buflen > vmcore_size - *fpos)
113 buflen = vmcore_size - *fpos;
115 /* Read ELF core header */
116 if (*fpos < elfcorebuf_sz) {
117 tsz = elfcorebuf_sz - *fpos;
118 if (buflen < tsz)
119 tsz = buflen;
120 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
121 return -EFAULT;
122 buflen -= tsz;
123 *fpos += tsz;
124 buffer += tsz;
125 acc += tsz;
127 /* leave now if filled buffer already */
128 if (buflen == 0)
129 return acc;
132 start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
133 if (!curr_m)
134 return -EINVAL;
135 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
136 tsz = buflen;
138 /* Calculate left bytes in current memory segment. */
139 nr_bytes = (curr_m->size - (start - curr_m->paddr));
140 if (tsz > nr_bytes)
141 tsz = nr_bytes;
143 while (buflen) {
144 tmp = read_from_oldmem(buffer, tsz, &start, 1);
145 if (tmp < 0)
146 return tmp;
147 buflen -= tsz;
148 *fpos += tsz;
149 buffer += tsz;
150 acc += tsz;
151 if (start >= (curr_m->paddr + curr_m->size)) {
152 if (curr_m->list.next == &vmcore_list)
153 return acc; /*EOF*/
154 curr_m = list_entry(curr_m->list.next,
155 struct vmcore, list);
156 start = curr_m->paddr;
158 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
159 tsz = buflen;
160 /* Calculate left bytes in current memory segment. */
161 nr_bytes = (curr_m->size - (start - curr_m->paddr));
162 if (tsz > nr_bytes)
163 tsz = nr_bytes;
165 return acc;
168 static int open_vmcore(struct inode *inode, struct file *filp)
170 return 0;
173 const struct file_operations proc_vmcore_operations = {
174 .read = read_vmcore,
175 .open = open_vmcore,
178 static struct vmcore* __init get_new_element(void)
180 struct vmcore *p;
182 p = kmalloc(sizeof(*p), GFP_KERNEL);
183 if (p)
184 memset(p, 0, sizeof(*p));
185 return p;
188 static u64 __init get_vmcore_size_elf64(char *elfptr)
190 int i;
191 u64 size;
192 Elf64_Ehdr *ehdr_ptr;
193 Elf64_Phdr *phdr_ptr;
195 ehdr_ptr = (Elf64_Ehdr *)elfptr;
196 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
197 size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
198 for (i = 0; i < ehdr_ptr->e_phnum; i++) {
199 size += phdr_ptr->p_memsz;
200 phdr_ptr++;
202 return size;
205 static u64 __init get_vmcore_size_elf32(char *elfptr)
207 int i;
208 u64 size;
209 Elf32_Ehdr *ehdr_ptr;
210 Elf32_Phdr *phdr_ptr;
212 ehdr_ptr = (Elf32_Ehdr *)elfptr;
213 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
214 size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
215 for (i = 0; i < ehdr_ptr->e_phnum; i++) {
216 size += phdr_ptr->p_memsz;
217 phdr_ptr++;
219 return size;
222 /* Merges all the PT_NOTE headers into one. */
223 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
224 struct list_head *vc_list)
226 int i, nr_ptnote=0, rc=0;
227 char *tmp;
228 Elf64_Ehdr *ehdr_ptr;
229 Elf64_Phdr phdr, *phdr_ptr;
230 Elf64_Nhdr *nhdr_ptr;
231 u64 phdr_sz = 0, note_off;
233 ehdr_ptr = (Elf64_Ehdr *)elfptr;
234 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
235 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
236 int j;
237 void *notes_section;
238 struct vmcore *new;
239 u64 offset, max_sz, sz, real_sz = 0;
240 if (phdr_ptr->p_type != PT_NOTE)
241 continue;
242 nr_ptnote++;
243 max_sz = phdr_ptr->p_memsz;
244 offset = phdr_ptr->p_offset;
245 notes_section = kmalloc(max_sz, GFP_KERNEL);
246 if (!notes_section)
247 return -ENOMEM;
248 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
249 if (rc < 0) {
250 kfree(notes_section);
251 return rc;
253 nhdr_ptr = notes_section;
254 for (j = 0; j < max_sz; j += sz) {
255 if (nhdr_ptr->n_namesz == 0)
256 break;
257 sz = sizeof(Elf64_Nhdr) +
258 ((nhdr_ptr->n_namesz + 3) & ~3) +
259 ((nhdr_ptr->n_descsz + 3) & ~3);
260 real_sz += sz;
261 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
264 /* Add this contiguous chunk of notes section to vmcore list.*/
265 new = get_new_element();
266 if (!new) {
267 kfree(notes_section);
268 return -ENOMEM;
270 new->paddr = phdr_ptr->p_offset;
271 new->size = real_sz;
272 list_add_tail(&new->list, vc_list);
273 phdr_sz += real_sz;
274 kfree(notes_section);
277 /* Prepare merged PT_NOTE program header. */
278 phdr.p_type = PT_NOTE;
279 phdr.p_flags = 0;
280 note_off = sizeof(Elf64_Ehdr) +
281 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
282 phdr.p_offset = note_off;
283 phdr.p_vaddr = phdr.p_paddr = 0;
284 phdr.p_filesz = phdr.p_memsz = phdr_sz;
285 phdr.p_align = 0;
287 /* Add merged PT_NOTE program header*/
288 tmp = elfptr + sizeof(Elf64_Ehdr);
289 memcpy(tmp, &phdr, sizeof(phdr));
290 tmp += sizeof(phdr);
292 /* Remove unwanted PT_NOTE program headers. */
293 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
294 *elfsz = *elfsz - i;
295 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
297 /* Modify e_phnum to reflect merged headers. */
298 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
300 return 0;
303 /* Merges all the PT_NOTE headers into one. */
304 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
305 struct list_head *vc_list)
307 int i, nr_ptnote=0, rc=0;
308 char *tmp;
309 Elf32_Ehdr *ehdr_ptr;
310 Elf32_Phdr phdr, *phdr_ptr;
311 Elf32_Nhdr *nhdr_ptr;
312 u64 phdr_sz = 0, note_off;
314 ehdr_ptr = (Elf32_Ehdr *)elfptr;
315 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
316 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
317 int j;
318 void *notes_section;
319 struct vmcore *new;
320 u64 offset, max_sz, sz, real_sz = 0;
321 if (phdr_ptr->p_type != PT_NOTE)
322 continue;
323 nr_ptnote++;
324 max_sz = phdr_ptr->p_memsz;
325 offset = phdr_ptr->p_offset;
326 notes_section = kmalloc(max_sz, GFP_KERNEL);
327 if (!notes_section)
328 return -ENOMEM;
329 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
330 if (rc < 0) {
331 kfree(notes_section);
332 return rc;
334 nhdr_ptr = notes_section;
335 for (j = 0; j < max_sz; j += sz) {
336 if (nhdr_ptr->n_namesz == 0)
337 break;
338 sz = sizeof(Elf32_Nhdr) +
339 ((nhdr_ptr->n_namesz + 3) & ~3) +
340 ((nhdr_ptr->n_descsz + 3) & ~3);
341 real_sz += sz;
342 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
345 /* Add this contiguous chunk of notes section to vmcore list.*/
346 new = get_new_element();
347 if (!new) {
348 kfree(notes_section);
349 return -ENOMEM;
351 new->paddr = phdr_ptr->p_offset;
352 new->size = real_sz;
353 list_add_tail(&new->list, vc_list);
354 phdr_sz += real_sz;
355 kfree(notes_section);
358 /* Prepare merged PT_NOTE program header. */
359 phdr.p_type = PT_NOTE;
360 phdr.p_flags = 0;
361 note_off = sizeof(Elf32_Ehdr) +
362 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
363 phdr.p_offset = note_off;
364 phdr.p_vaddr = phdr.p_paddr = 0;
365 phdr.p_filesz = phdr.p_memsz = phdr_sz;
366 phdr.p_align = 0;
368 /* Add merged PT_NOTE program header*/
369 tmp = elfptr + sizeof(Elf32_Ehdr);
370 memcpy(tmp, &phdr, sizeof(phdr));
371 tmp += sizeof(phdr);
373 /* Remove unwanted PT_NOTE program headers. */
374 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
375 *elfsz = *elfsz - i;
376 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
378 /* Modify e_phnum to reflect merged headers. */
379 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
381 return 0;
384 /* Add memory chunks represented by program headers to vmcore list. Also update
385 * the new offset fields of exported program headers. */
386 static int __init process_ptload_program_headers_elf64(char *elfptr,
387 size_t elfsz,
388 struct list_head *vc_list)
390 int i;
391 Elf64_Ehdr *ehdr_ptr;
392 Elf64_Phdr *phdr_ptr;
393 loff_t vmcore_off;
394 struct vmcore *new;
396 ehdr_ptr = (Elf64_Ehdr *)elfptr;
397 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
399 /* First program header is PT_NOTE header. */
400 vmcore_off = sizeof(Elf64_Ehdr) +
401 (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
402 phdr_ptr->p_memsz; /* Note sections */
404 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
405 if (phdr_ptr->p_type != PT_LOAD)
406 continue;
408 /* Add this contiguous chunk of memory to vmcore list.*/
409 new = get_new_element();
410 if (!new)
411 return -ENOMEM;
412 new->paddr = phdr_ptr->p_offset;
413 new->size = phdr_ptr->p_memsz;
414 list_add_tail(&new->list, vc_list);
416 /* Update the program header offset. */
417 phdr_ptr->p_offset = vmcore_off;
418 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
420 return 0;
423 static int __init process_ptload_program_headers_elf32(char *elfptr,
424 size_t elfsz,
425 struct list_head *vc_list)
427 int i;
428 Elf32_Ehdr *ehdr_ptr;
429 Elf32_Phdr *phdr_ptr;
430 loff_t vmcore_off;
431 struct vmcore *new;
433 ehdr_ptr = (Elf32_Ehdr *)elfptr;
434 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
436 /* First program header is PT_NOTE header. */
437 vmcore_off = sizeof(Elf32_Ehdr) +
438 (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
439 phdr_ptr->p_memsz; /* Note sections */
441 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
442 if (phdr_ptr->p_type != PT_LOAD)
443 continue;
445 /* Add this contiguous chunk of memory to vmcore list.*/
446 new = get_new_element();
447 if (!new)
448 return -ENOMEM;
449 new->paddr = phdr_ptr->p_offset;
450 new->size = phdr_ptr->p_memsz;
451 list_add_tail(&new->list, vc_list);
453 /* Update the program header offset */
454 phdr_ptr->p_offset = vmcore_off;
455 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
457 return 0;
460 /* Sets offset fields of vmcore elements. */
461 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
462 struct list_head *vc_list)
464 loff_t vmcore_off;
465 Elf64_Ehdr *ehdr_ptr;
466 struct vmcore *m;
468 ehdr_ptr = (Elf64_Ehdr *)elfptr;
470 /* Skip Elf header and program headers. */
471 vmcore_off = sizeof(Elf64_Ehdr) +
472 (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
474 list_for_each_entry(m, vc_list, list) {
475 m->offset = vmcore_off;
476 vmcore_off += m->size;
480 /* Sets offset fields of vmcore elements. */
481 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
482 struct list_head *vc_list)
484 loff_t vmcore_off;
485 Elf32_Ehdr *ehdr_ptr;
486 struct vmcore *m;
488 ehdr_ptr = (Elf32_Ehdr *)elfptr;
490 /* Skip Elf header and program headers. */
491 vmcore_off = sizeof(Elf32_Ehdr) +
492 (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
494 list_for_each_entry(m, vc_list, list) {
495 m->offset = vmcore_off;
496 vmcore_off += m->size;
500 static int __init parse_crash_elf64_headers(void)
502 int rc=0;
503 Elf64_Ehdr ehdr;
504 u64 addr;
506 addr = elfcorehdr_addr;
508 /* Read Elf header */
509 rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
510 if (rc < 0)
511 return rc;
513 /* Do some basic Verification. */
514 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
515 (ehdr.e_type != ET_CORE) ||
516 !vmcore_elf_check_arch(&ehdr) ||
517 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
518 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
519 ehdr.e_version != EV_CURRENT ||
520 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
521 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
522 ehdr.e_phnum == 0) {
523 printk(KERN_WARNING "Warning: Core image elf header is not"
524 "sane\n");
525 return -EINVAL;
528 /* Read in all elf headers. */
529 elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
530 elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
531 if (!elfcorebuf)
532 return -ENOMEM;
533 addr = elfcorehdr_addr;
534 rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
535 if (rc < 0) {
536 kfree(elfcorebuf);
537 return rc;
540 /* Merge all PT_NOTE headers into one. */
541 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
542 if (rc) {
543 kfree(elfcorebuf);
544 return rc;
546 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
547 &vmcore_list);
548 if (rc) {
549 kfree(elfcorebuf);
550 return rc;
552 set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
553 return 0;
556 static int __init parse_crash_elf32_headers(void)
558 int rc=0;
559 Elf32_Ehdr ehdr;
560 u64 addr;
562 addr = elfcorehdr_addr;
564 /* Read Elf header */
565 rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
566 if (rc < 0)
567 return rc;
569 /* Do some basic Verification. */
570 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
571 (ehdr.e_type != ET_CORE) ||
572 !elf_check_arch(&ehdr) ||
573 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
574 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
575 ehdr.e_version != EV_CURRENT ||
576 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
577 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
578 ehdr.e_phnum == 0) {
579 printk(KERN_WARNING "Warning: Core image elf header is not"
580 "sane\n");
581 return -EINVAL;
584 /* Read in all elf headers. */
585 elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
586 elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
587 if (!elfcorebuf)
588 return -ENOMEM;
589 addr = elfcorehdr_addr;
590 rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
591 if (rc < 0) {
592 kfree(elfcorebuf);
593 return rc;
596 /* Merge all PT_NOTE headers into one. */
597 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
598 if (rc) {
599 kfree(elfcorebuf);
600 return rc;
602 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
603 &vmcore_list);
604 if (rc) {
605 kfree(elfcorebuf);
606 return rc;
608 set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
609 return 0;
612 static int __init parse_crash_elf_headers(void)
614 unsigned char e_ident[EI_NIDENT];
615 u64 addr;
616 int rc=0;
618 addr = elfcorehdr_addr;
619 rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
620 if (rc < 0)
621 return rc;
622 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
623 printk(KERN_WARNING "Warning: Core image elf header"
624 " not found\n");
625 return -EINVAL;
628 if (e_ident[EI_CLASS] == ELFCLASS64) {
629 rc = parse_crash_elf64_headers();
630 if (rc)
631 return rc;
633 /* Determine vmcore size. */
634 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
635 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
636 rc = parse_crash_elf32_headers();
637 if (rc)
638 return rc;
640 /* Determine vmcore size. */
641 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
642 } else {
643 printk(KERN_WARNING "Warning: Core image elf header is not"
644 " sane\n");
645 return -EINVAL;
647 return 0;
650 /* Init function for vmcore module. */
651 static int __init vmcore_init(void)
653 int rc = 0;
655 /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
656 if (!(elfcorehdr_addr < ELFCORE_ADDR_MAX))
657 return rc;
658 rc = parse_crash_elf_headers();
659 if (rc) {
660 printk(KERN_WARNING "Kdump: vmcore not initialized\n");
661 return rc;
664 /* Initialize /proc/vmcore size if proc is already up. */
665 if (proc_vmcore)
666 proc_vmcore->size = vmcore_size;
667 return 0;
669 module_init(vmcore_init)