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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[linux-2.6.git] / fs / proc / vmcore.c
blob17f7e080d7ff6c5c301c6b71bd1c793b1439357c
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
7 *
8 */
9
10 #include <linux/mm.h>
11 #include <linux/kcore.h>
12 #include <linux/user.h>
13 #include <linux/elf.h>
14 #include <linux/elfcore.h>
15 #include <linux/export.h>
16 #include <linux/slab.h>
17 #include <linux/highmem.h>
18 #include <linux/printk.h>
19 #include <linux/bootmem.h>
20 #include <linux/init.h>
21 #include <linux/crash_dump.h>
22 #include <linux/list.h>
23 #include <asm/uaccess.h>
24 #include <asm/io.h>
25 #include "internal.h"
26
27 /* List representing chunks of contiguous memory areas and their offsets in
28 * vmcore file.
29 */
30 static LIST_HEAD(vmcore_list);
31
32 /* Stores the pointer to the buffer containing kernel elf core headers. */
33 static char *elfcorebuf;
34 static size_t elfcorebuf_sz;
35
36 /* Total size of vmcore file. */
37 static u64 vmcore_size;
38
39 static struct proc_dir_entry *proc_vmcore = NULL;
40
41 /*
42 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
43 * The called function has to take care of module refcounting.
44 */
45 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
46
47 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
48 {
49 if (oldmem_pfn_is_ram)
50 return -EBUSY;
51 oldmem_pfn_is_ram = fn;
52 return 0;
53 }
54 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
55
56 void unregister_oldmem_pfn_is_ram(void)
57 {
58 oldmem_pfn_is_ram = NULL;
59 wmb();
60 }
61 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
62
63 static int pfn_is_ram(unsigned long pfn)
64 {
65 int (*fn)(unsigned long pfn);
66 /* pfn is ram unless fn() checks pagetype */
67 int ret = 1;
68
69 /*
70 * Ask hypervisor if the pfn is really ram.
71 * A ballooned page contains no data and reading from such a page
72 * will cause high load in the hypervisor.
73 */
74 fn = oldmem_pfn_is_ram;
75 if (fn)
76 ret = fn(pfn);
77
78 return ret;
79 }
80
81 /* Reads a page from the oldmem device from given offset. */
82 static ssize_t read_from_oldmem(char *buf, size_t count,
83 u64 *ppos, int userbuf)
84 {
85 unsigned long pfn, offset;
86 size_t nr_bytes;
87 ssize_t read = 0, tmp;
88
89 if (!count)
90 return 0;
91
92 offset = (unsigned long)(*ppos % PAGE_SIZE);
93 pfn = (unsigned long)(*ppos / PAGE_SIZE);
94
95 do {
96 if (count > (PAGE_SIZE - offset))
97 nr_bytes = PAGE_SIZE - offset;
98 else
99 nr_bytes = count;
100
101 /* If pfn is not ram, return zeros for sparse dump files */
102 if (pfn_is_ram(pfn) == 0)
103 memset(buf, 0, nr_bytes);
104 else {
105 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
106 offset, userbuf);
107 if (tmp < 0)
108 return tmp;
109 }
110 *ppos += nr_bytes;
111 count -= nr_bytes;
112 buf += nr_bytes;
113 read += nr_bytes;
114 ++pfn;
115 offset = 0;
116 } while (count);
117
118 return read;
119 }
120
121 /* Maps vmcore file offset to respective physical address in memroy. */
122 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
123 struct vmcore **m_ptr)
124 {
125 struct vmcore *m;
126 u64 paddr;
127
128 list_for_each_entry(m, vc_list, list) {
129 u64 start, end;
130 start = m->offset;
131 end = m->offset + m->size - 1;
132 if (offset >= start && offset <= end) {
133 paddr = m->paddr + offset - start;
134 *m_ptr = m;
135 return paddr;
136 }
137 }
138 *m_ptr = NULL;
139 return 0;
140 }
141
142 /* Read from the ELF header and then the crash dump. On error, negative value is
143 * returned otherwise number of bytes read are returned.
144 */
145 static ssize_t read_vmcore(struct file *file, char __user *buffer,
146 size_t buflen, loff_t *fpos)
147 {
148 ssize_t acc = 0, tmp;
149 size_t tsz;
150 u64 start, nr_bytes;
151 struct vmcore *curr_m = NULL;
152
153 if (buflen == 0 || *fpos >= vmcore_size)
154 return 0;
155
156 /* trim buflen to not go beyond EOF */
157 if (buflen > vmcore_size - *fpos)
158 buflen = vmcore_size - *fpos;
159
160 /* Read ELF core header */
161 if (*fpos < elfcorebuf_sz) {
162 tsz = elfcorebuf_sz - *fpos;
163 if (buflen < tsz)
164 tsz = buflen;
165 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
166 return -EFAULT;
167 buflen -= tsz;
168 *fpos += tsz;
169 buffer += tsz;
170 acc += tsz;
171
172 /* leave now if filled buffer already */
173 if (buflen == 0)
174 return acc;
175 }
176
177 start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
178 if (!curr_m)
179 return -EINVAL;
180
181 while (buflen) {
182 tsz = min_t(size_t, buflen, PAGE_SIZE - (start & ~PAGE_MASK));
183
184 /* Calculate left bytes in current memory segment. */
185 nr_bytes = (curr_m->size - (start - curr_m->paddr));
186 if (tsz > nr_bytes)
187 tsz = nr_bytes;
188
189 tmp = read_from_oldmem(buffer, tsz, &start, 1);
190 if (tmp < 0)
191 return tmp;
192 buflen -= tsz;
193 *fpos += tsz;
194 buffer += tsz;
195 acc += tsz;
196 if (start >= (curr_m->paddr + curr_m->size)) {
197 if (curr_m->list.next == &vmcore_list)
198 return acc; /*EOF*/
199 curr_m = list_entry(curr_m->list.next,
200 struct vmcore, list);
201 start = curr_m->paddr;
202 }
203 }
204 return acc;
205 }
206
207 static const struct file_operations proc_vmcore_operations = {
208 .read = read_vmcore,
209 .llseek = default_llseek,
210 };
211
212 static struct vmcore* __init get_new_element(void)
213 {
214 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
215 }
216
217 static u64 __init get_vmcore_size_elf64(char *elfptr)
218 {
219 int i;
220 u64 size;
221 Elf64_Ehdr *ehdr_ptr;
222 Elf64_Phdr *phdr_ptr;
223
224 ehdr_ptr = (Elf64_Ehdr *)elfptr;
225 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
226 size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
227 for (i = 0; i < ehdr_ptr->e_phnum; i++) {
228 size += phdr_ptr->p_memsz;
229 phdr_ptr++;
230 }
231 return size;
232 }
233
234 static u64 __init get_vmcore_size_elf32(char *elfptr)
235 {
236 int i;
237 u64 size;
238 Elf32_Ehdr *ehdr_ptr;
239 Elf32_Phdr *phdr_ptr;
240
241 ehdr_ptr = (Elf32_Ehdr *)elfptr;
242 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
243 size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
244 for (i = 0; i < ehdr_ptr->e_phnum; i++) {
245 size += phdr_ptr->p_memsz;
246 phdr_ptr++;
247 }
248 return size;
249 }
250
251 /* Merges all the PT_NOTE headers into one. */
252 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
253 struct list_head *vc_list)
254 {
255 int i, nr_ptnote=0, rc=0;
256 char *tmp;
257 Elf64_Ehdr *ehdr_ptr;
258 Elf64_Phdr phdr, *phdr_ptr;
259 Elf64_Nhdr *nhdr_ptr;
260 u64 phdr_sz = 0, note_off;
261
262 ehdr_ptr = (Elf64_Ehdr *)elfptr;
263 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
264 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
265 int j;
266 void *notes_section;
267 struct vmcore *new;
268 u64 offset, max_sz, sz, real_sz = 0;
269 if (phdr_ptr->p_type != PT_NOTE)
270 continue;
271 nr_ptnote++;
272 max_sz = phdr_ptr->p_memsz;
273 offset = phdr_ptr->p_offset;
274 notes_section = kmalloc(max_sz, GFP_KERNEL);
275 if (!notes_section)
276 return -ENOMEM;
277 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
278 if (rc < 0) {
279 kfree(notes_section);
280 return rc;
281 }
282 nhdr_ptr = notes_section;
283 for (j = 0; j < max_sz; j += sz) {
284 if (nhdr_ptr->n_namesz == 0)
285 break;
286 sz = sizeof(Elf64_Nhdr) +
287 ((nhdr_ptr->n_namesz + 3) & ~3) +
288 ((nhdr_ptr->n_descsz + 3) & ~3);
289 real_sz += sz;
290 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
291 }
292
293 /* Add this contiguous chunk of notes section to vmcore list.*/
294 new = get_new_element();
295 if (!new) {
296 kfree(notes_section);
297 return -ENOMEM;
298 }
299 new->paddr = phdr_ptr->p_offset;
300 new->size = real_sz;
301 list_add_tail(&new->list, vc_list);
302 phdr_sz += real_sz;
303 kfree(notes_section);
304 }
305
306 /* Prepare merged PT_NOTE program header. */
307 phdr.p_type = PT_NOTE;
308 phdr.p_flags = 0;
309 note_off = sizeof(Elf64_Ehdr) +
310 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
311 phdr.p_offset = note_off;
312 phdr.p_vaddr = phdr.p_paddr = 0;
313 phdr.p_filesz = phdr.p_memsz = phdr_sz;
314 phdr.p_align = 0;
315
316 /* Add merged PT_NOTE program header*/
317 tmp = elfptr + sizeof(Elf64_Ehdr);
318 memcpy(tmp, &phdr, sizeof(phdr));
319 tmp += sizeof(phdr);
320
321 /* Remove unwanted PT_NOTE program headers. */
322 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
323 *elfsz = *elfsz - i;
324 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
325
326 /* Modify e_phnum to reflect merged headers. */
327 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
328
329 return 0;
330 }
331
332 /* Merges all the PT_NOTE headers into one. */
333 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
334 struct list_head *vc_list)
335 {
336 int i, nr_ptnote=0, rc=0;
337 char *tmp;
338 Elf32_Ehdr *ehdr_ptr;
339 Elf32_Phdr phdr, *phdr_ptr;
340 Elf32_Nhdr *nhdr_ptr;
341 u64 phdr_sz = 0, note_off;
342
343 ehdr_ptr = (Elf32_Ehdr *)elfptr;
344 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
345 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
346 int j;
347 void *notes_section;
348 struct vmcore *new;
349 u64 offset, max_sz, sz, real_sz = 0;
350 if (phdr_ptr->p_type != PT_NOTE)
351 continue;
352 nr_ptnote++;
353 max_sz = phdr_ptr->p_memsz;
354 offset = phdr_ptr->p_offset;
355 notes_section = kmalloc(max_sz, GFP_KERNEL);
356 if (!notes_section)
357 return -ENOMEM;
358 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
359 if (rc < 0) {
360 kfree(notes_section);
361 return rc;
362 }
363 nhdr_ptr = notes_section;
364 for (j = 0; j < max_sz; j += sz) {
365 if (nhdr_ptr->n_namesz == 0)
366 break;
367 sz = sizeof(Elf32_Nhdr) +
368 ((nhdr_ptr->n_namesz + 3) & ~3) +
369 ((nhdr_ptr->n_descsz + 3) & ~3);
370 real_sz += sz;
371 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
372 }
373
374 /* Add this contiguous chunk of notes section to vmcore list.*/
375 new = get_new_element();
376 if (!new) {
377 kfree(notes_section);
378 return -ENOMEM;
379 }
380 new->paddr = phdr_ptr->p_offset;
381 new->size = real_sz;
382 list_add_tail(&new->list, vc_list);
383 phdr_sz += real_sz;
384 kfree(notes_section);
385 }
386
387 /* Prepare merged PT_NOTE program header. */
388 phdr.p_type = PT_NOTE;
389 phdr.p_flags = 0;
390 note_off = sizeof(Elf32_Ehdr) +
391 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
392 phdr.p_offset = note_off;
393 phdr.p_vaddr = phdr.p_paddr = 0;
394 phdr.p_filesz = phdr.p_memsz = phdr_sz;
395 phdr.p_align = 0;
396
397 /* Add merged PT_NOTE program header*/
398 tmp = elfptr + sizeof(Elf32_Ehdr);
399 memcpy(tmp, &phdr, sizeof(phdr));
400 tmp += sizeof(phdr);
401
402 /* Remove unwanted PT_NOTE program headers. */
403 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
404 *elfsz = *elfsz - i;
405 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
406
407 /* Modify e_phnum to reflect merged headers. */
408 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
409
410 return 0;
411 }
412
413 /* Add memory chunks represented by program headers to vmcore list. Also update
414 * the new offset fields of exported program headers. */
415 static int __init process_ptload_program_headers_elf64(char *elfptr,
416 size_t elfsz,
417 struct list_head *vc_list)
418 {
419 int i;
420 Elf64_Ehdr *ehdr_ptr;
421 Elf64_Phdr *phdr_ptr;
422 loff_t vmcore_off;
423 struct vmcore *new;
424
425 ehdr_ptr = (Elf64_Ehdr *)elfptr;
426 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
427
428 /* First program header is PT_NOTE header. */
429 vmcore_off = sizeof(Elf64_Ehdr) +
430 (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
431 phdr_ptr->p_memsz; /* Note sections */
432
433 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
434 if (phdr_ptr->p_type != PT_LOAD)
435 continue;
436
437 /* Add this contiguous chunk of memory to vmcore list.*/
438 new = get_new_element();
439 if (!new)
440 return -ENOMEM;
441 new->paddr = phdr_ptr->p_offset;
442 new->size = phdr_ptr->p_memsz;
443 list_add_tail(&new->list, vc_list);
444
445 /* Update the program header offset. */
446 phdr_ptr->p_offset = vmcore_off;
447 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
448 }
449 return 0;
450 }
451
452 static int __init process_ptload_program_headers_elf32(char *elfptr,
453 size_t elfsz,
454 struct list_head *vc_list)
455 {
456 int i;
457 Elf32_Ehdr *ehdr_ptr;
458 Elf32_Phdr *phdr_ptr;
459 loff_t vmcore_off;
460 struct vmcore *new;
461
462 ehdr_ptr = (Elf32_Ehdr *)elfptr;
463 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
464
465 /* First program header is PT_NOTE header. */
466 vmcore_off = sizeof(Elf32_Ehdr) +
467 (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
468 phdr_ptr->p_memsz; /* Note sections */
469
470 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
471 if (phdr_ptr->p_type != PT_LOAD)
472 continue;
473
474 /* Add this contiguous chunk of memory to vmcore list.*/
475 new = get_new_element();
476 if (!new)
477 return -ENOMEM;
478 new->paddr = phdr_ptr->p_offset;
479 new->size = phdr_ptr->p_memsz;
480 list_add_tail(&new->list, vc_list);
481
482 /* Update the program header offset */
483 phdr_ptr->p_offset = vmcore_off;
484 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
485 }
486 return 0;
487 }
488
489 /* Sets offset fields of vmcore elements. */
490 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
491 struct list_head *vc_list)
492 {
493 loff_t vmcore_off;
494 Elf64_Ehdr *ehdr_ptr;
495 struct vmcore *m;
496
497 ehdr_ptr = (Elf64_Ehdr *)elfptr;
498
499 /* Skip Elf header and program headers. */
500 vmcore_off = sizeof(Elf64_Ehdr) +
501 (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
502
503 list_for_each_entry(m, vc_list, list) {
504 m->offset = vmcore_off;
505 vmcore_off += m->size;
506 }
507 }
508
509 /* Sets offset fields of vmcore elements. */
510 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
511 struct list_head *vc_list)
512 {
513 loff_t vmcore_off;
514 Elf32_Ehdr *ehdr_ptr;
515 struct vmcore *m;
516
517 ehdr_ptr = (Elf32_Ehdr *)elfptr;
518
519 /* Skip Elf header and program headers. */
520 vmcore_off = sizeof(Elf32_Ehdr) +
521 (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
522
523 list_for_each_entry(m, vc_list, list) {
524 m->offset = vmcore_off;
525 vmcore_off += m->size;
526 }
527 }
528
529 static int __init parse_crash_elf64_headers(void)
530 {
531 int rc=0;
532 Elf64_Ehdr ehdr;
533 u64 addr;
534
535 addr = elfcorehdr_addr;
536
537 /* Read Elf header */
538 rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
539 if (rc < 0)
540 return rc;
541
542 /* Do some basic Verification. */
543 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
544 (ehdr.e_type != ET_CORE) ||
545 !vmcore_elf64_check_arch(&ehdr) ||
546 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
547 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
548 ehdr.e_version != EV_CURRENT ||
549 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
550 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
551 ehdr.e_phnum == 0) {
552 pr_warn("Warning: Core image elf header is not sane\n");
553 return -EINVAL;
554 }
555
556 /* Read in all elf headers. */
557 elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
558 elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
559 if (!elfcorebuf)
560 return -ENOMEM;
561 addr = elfcorehdr_addr;
562 rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
563 if (rc < 0) {
564 kfree(elfcorebuf);
565 return rc;
566 }
567
568 /* Merge all PT_NOTE headers into one. */
569 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
570 if (rc) {
571 kfree(elfcorebuf);
572 return rc;
573 }
574 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
575 &vmcore_list);
576 if (rc) {
577 kfree(elfcorebuf);
578 return rc;
579 }
580 set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
581 return 0;
582 }
583
584 static int __init parse_crash_elf32_headers(void)
585 {
586 int rc=0;
587 Elf32_Ehdr ehdr;
588 u64 addr;
589
590 addr = elfcorehdr_addr;
591
592 /* Read Elf header */
593 rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
594 if (rc < 0)
595 return rc;
596
597 /* Do some basic Verification. */
598 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
599 (ehdr.e_type != ET_CORE) ||
600 !elf_check_arch(&ehdr) ||
601 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
602 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
603 ehdr.e_version != EV_CURRENT ||
604 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
605 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
606 ehdr.e_phnum == 0) {
607 pr_warn("Warning: Core image elf header is not sane\n");
608 return -EINVAL;
609 }
610
611 /* Read in all elf headers. */
612 elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
613 elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
614 if (!elfcorebuf)
615 return -ENOMEM;
616 addr = elfcorehdr_addr;
617 rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
618 if (rc < 0) {
619 kfree(elfcorebuf);
620 return rc;
621 }
622
623 /* Merge all PT_NOTE headers into one. */
624 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
625 if (rc) {
626 kfree(elfcorebuf);
627 return rc;
628 }
629 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
630 &vmcore_list);
631 if (rc) {
632 kfree(elfcorebuf);
633 return rc;
634 }
635 set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
636 return 0;
637 }
638
639 static int __init parse_crash_elf_headers(void)
640 {
641 unsigned char e_ident[EI_NIDENT];
642 u64 addr;
643 int rc=0;
644
645 addr = elfcorehdr_addr;
646 rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
647 if (rc < 0)
648 return rc;
649 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
650 pr_warn("Warning: Core image elf header not found\n");
651 return -EINVAL;
652 }
653
654 if (e_ident[EI_CLASS] == ELFCLASS64) {
655 rc = parse_crash_elf64_headers();
656 if (rc)
657 return rc;
658
659 /* Determine vmcore size. */
660 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
661 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
662 rc = parse_crash_elf32_headers();
663 if (rc)
664 return rc;
665
666 /* Determine vmcore size. */
667 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
668 } else {
669 pr_warn("Warning: Core image elf header is not sane\n");
670 return -EINVAL;
671 }
672 return 0;
673 }
674
675 /* Init function for vmcore module. */
676 static int __init vmcore_init(void)
677 {
678 int rc = 0;
679
680 /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
681 if (!(is_vmcore_usable()))
682 return rc;
683 rc = parse_crash_elf_headers();
684 if (rc) {
685 pr_warn("Kdump: vmcore not initialized\n");
686 return rc;
687 }
688
689 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
690 if (proc_vmcore)
691 proc_vmcore->size = vmcore_size;
692 return 0;
693 }
694 module_init(vmcore_init)
695
696 /* Cleanup function for vmcore module. */
697 void vmcore_cleanup(void)
698 {
699 struct list_head *pos, *next;
700
701 if (proc_vmcore) {
702 proc_remove(proc_vmcore);
703 proc_vmcore = NULL;
704 }
705
706 /* clear the vmcore list. */
707 list_for_each_safe(pos, next, &vmcore_list) {
708 struct vmcore *m;
709
710 m = list_entry(pos, struct vmcore, list);
711 list_del(&m->list);
712 kfree(m);
713 }
714 kfree(elfcorebuf);
715 elfcorebuf = NULL;
716 }
717 EXPORT_SYMBOL_GPL(vmcore_cleanup);
Linus' kernel tree