0d5071d29985b527eb4d2f6819b08646c82a2a30
[linux-3.10.git] / fs / proc / vmcore.c
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/proc_fs.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/bootmem.h>
19 #include <linux/init.h>
20 #include <linux/crash_dump.h>
21 #include <linux/list.h>
22 #include <asm/uaccess.h>
23 #include <asm/io.h>
24
25 /* List representing chunks of contiguous memory areas and their offsets in
26  * vmcore file.
27  */
28 static LIST_HEAD(vmcore_list);
29
30 /* Stores the pointer to the buffer containing kernel elf core headers. */
31 static char *elfcorebuf;
32 static size_t elfcorebuf_sz;
33
34 /* Total size of vmcore file. */
35 static u64 vmcore_size;
36
37 static struct proc_dir_entry *proc_vmcore = NULL;
38
39 /*
40  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
41  * The called function has to take care of module refcounting.
42  */
43 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
44
45 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
46 {
47         if (oldmem_pfn_is_ram)
48                 return -EBUSY;
49         oldmem_pfn_is_ram = fn;
50         return 0;
51 }
52 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
53
54 void unregister_oldmem_pfn_is_ram(void)
55 {
56         oldmem_pfn_is_ram = NULL;
57         wmb();
58 }
59 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
60
61 static int pfn_is_ram(unsigned long pfn)
62 {
63         int (*fn)(unsigned long pfn);
64         /* pfn is ram unless fn() checks pagetype */
65         int ret = 1;
66
67         /*
68          * Ask hypervisor if the pfn is really ram.
69          * A ballooned page contains no data and reading from such a page
70          * will cause high load in the hypervisor.
71          */
72         fn = oldmem_pfn_is_ram;
73         if (fn)
74                 ret = fn(pfn);
75
76         return ret;
77 }
78
79 /* Reads a page from the oldmem device from given offset. */
80 static ssize_t read_from_oldmem(char *buf, size_t count,
81                                 u64 *ppos, int userbuf)
82 {
83         unsigned long pfn, offset;
84         size_t nr_bytes;
85         ssize_t read = 0, tmp;
86
87         if (!count)
88                 return 0;
89
90         offset = (unsigned long)(*ppos % PAGE_SIZE);
91         pfn = (unsigned long)(*ppos / PAGE_SIZE);
92
93         do {
94                 if (count > (PAGE_SIZE - offset))
95                         nr_bytes = PAGE_SIZE - offset;
96                 else
97                         nr_bytes = count;
98
99                 /* If pfn is not ram, return zeros for sparse dump files */
100                 if (pfn_is_ram(pfn) == 0)
101                         memset(buf, 0, nr_bytes);
102                 else {
103                         tmp = copy_oldmem_page(pfn, buf, nr_bytes,
104                                                 offset, userbuf);
105                         if (tmp < 0)
106                                 return tmp;
107                 }
108                 *ppos += nr_bytes;
109                 count -= nr_bytes;
110                 buf += nr_bytes;
111                 read += nr_bytes;
112                 ++pfn;
113                 offset = 0;
114         } while (count);
115
116         return read;
117 }
118
119 /* Maps vmcore file offset to respective physical address in memroy. */
120 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
121                                         struct vmcore **m_ptr)
122 {
123         struct vmcore *m;
124         u64 paddr;
125
126         list_for_each_entry(m, vc_list, list) {
127                 u64 start, end;
128                 start = m->offset;
129                 end = m->offset + m->size - 1;
130                 if (offset >= start && offset <= end) {
131                         paddr = m->paddr + offset - start;
132                         *m_ptr = m;
133                         return paddr;
134                 }
135         }
136         *m_ptr = NULL;
137         return 0;
138 }
139
140 /* Read from the ELF header and then the crash dump. On error, negative value is
141  * returned otherwise number of bytes read are returned.
142  */
143 static ssize_t read_vmcore(struct file *file, char __user *buffer,
144                                 size_t buflen, loff_t *fpos)
145 {
146         ssize_t acc = 0, tmp;
147         size_t tsz;
148         u64 start, nr_bytes;
149         struct vmcore *curr_m = NULL;
150
151         if (buflen == 0 || *fpos >= vmcore_size)
152                 return 0;
153
154         /* trim buflen to not go beyond EOF */
155         if (buflen > vmcore_size - *fpos)
156                 buflen = vmcore_size - *fpos;
157
158         /* Read ELF core header */
159         if (*fpos < elfcorebuf_sz) {
160                 tsz = elfcorebuf_sz - *fpos;
161                 if (buflen < tsz)
162                         tsz = buflen;
163                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
164                         return -EFAULT;
165                 buflen -= tsz;
166                 *fpos += tsz;
167                 buffer += tsz;
168                 acc += tsz;
169
170                 /* leave now if filled buffer already */
171                 if (buflen == 0)
172                         return acc;
173         }
174
175         start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
176         if (!curr_m)
177                 return -EINVAL;
178         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
179                 tsz = buflen;
180
181         /* Calculate left bytes in current memory segment. */
182         nr_bytes = (curr_m->size - (start - curr_m->paddr));
183         if (tsz > nr_bytes)
184                 tsz = nr_bytes;
185
186         while (buflen) {
187                 tmp = read_from_oldmem(buffer, tsz, &start, 1);
188                 if (tmp < 0)
189                         return tmp;
190                 buflen -= tsz;
191                 *fpos += tsz;
192                 buffer += tsz;
193                 acc += tsz;
194                 if (start >= (curr_m->paddr + curr_m->size)) {
195                         if (curr_m->list.next == &vmcore_list)
196                                 return acc;     /*EOF*/
197                         curr_m = list_entry(curr_m->list.next,
198                                                 struct vmcore, list);
199                         start = curr_m->paddr;
200                 }
201                 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
202                         tsz = buflen;
203                 /* Calculate left bytes in current memory segment. */
204                 nr_bytes = (curr_m->size - (start - curr_m->paddr));
205                 if (tsz > nr_bytes)
206                         tsz = nr_bytes;
207         }
208         return acc;
209 }
210
211 static const struct file_operations proc_vmcore_operations = {
212         .read           = read_vmcore,
213         .llseek         = default_llseek,
214 };
215
216 static struct vmcore* __init get_new_element(void)
217 {
218         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
219 }
220
221 static u64 __init get_vmcore_size_elf64(char *elfptr)
222 {
223         int i;
224         u64 size;
225         Elf64_Ehdr *ehdr_ptr;
226         Elf64_Phdr *phdr_ptr;
227
228         ehdr_ptr = (Elf64_Ehdr *)elfptr;
229         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
230         size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
231         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
232                 size += phdr_ptr->p_memsz;
233                 phdr_ptr++;
234         }
235         return size;
236 }
237
238 static u64 __init get_vmcore_size_elf32(char *elfptr)
239 {
240         int i;
241         u64 size;
242         Elf32_Ehdr *ehdr_ptr;
243         Elf32_Phdr *phdr_ptr;
244
245         ehdr_ptr = (Elf32_Ehdr *)elfptr;
246         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
247         size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
248         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
249                 size += phdr_ptr->p_memsz;
250                 phdr_ptr++;
251         }
252         return size;
253 }
254
255 /* Merges all the PT_NOTE headers into one. */
256 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
257                                                 struct list_head *vc_list)
258 {
259         int i, nr_ptnote=0, rc=0;
260         char *tmp;
261         Elf64_Ehdr *ehdr_ptr;
262         Elf64_Phdr phdr, *phdr_ptr;
263         Elf64_Nhdr *nhdr_ptr;
264         u64 phdr_sz = 0, note_off;
265
266         ehdr_ptr = (Elf64_Ehdr *)elfptr;
267         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
268         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
269                 int j;
270                 void *notes_section;
271                 struct vmcore *new;
272                 u64 offset, max_sz, sz, real_sz = 0;
273                 if (phdr_ptr->p_type != PT_NOTE)
274                         continue;
275                 nr_ptnote++;
276                 max_sz = phdr_ptr->p_memsz;
277                 offset = phdr_ptr->p_offset;
278                 notes_section = kmalloc(max_sz, GFP_KERNEL);
279                 if (!notes_section)
280                         return -ENOMEM;
281                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
282                 if (rc < 0) {
283                         kfree(notes_section);
284                         return rc;
285                 }
286                 nhdr_ptr = notes_section;
287                 for (j = 0; j < max_sz; j += sz) {
288                         if (nhdr_ptr->n_namesz == 0)
289                                 break;
290                         sz = sizeof(Elf64_Nhdr) +
291                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
292                                 ((nhdr_ptr->n_descsz + 3) & ~3);
293                         real_sz += sz;
294                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
295                 }
296
297                 /* Add this contiguous chunk of notes section to vmcore list.*/
298                 new = get_new_element();
299                 if (!new) {
300                         kfree(notes_section);
301                         return -ENOMEM;
302                 }
303                 new->paddr = phdr_ptr->p_offset;
304                 new->size = real_sz;
305                 list_add_tail(&new->list, vc_list);
306                 phdr_sz += real_sz;
307                 kfree(notes_section);
308         }
309
310         /* Prepare merged PT_NOTE program header. */
311         phdr.p_type    = PT_NOTE;
312         phdr.p_flags   = 0;
313         note_off = sizeof(Elf64_Ehdr) +
314                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
315         phdr.p_offset  = note_off;
316         phdr.p_vaddr   = phdr.p_paddr = 0;
317         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
318         phdr.p_align   = 0;
319
320         /* Add merged PT_NOTE program header*/
321         tmp = elfptr + sizeof(Elf64_Ehdr);
322         memcpy(tmp, &phdr, sizeof(phdr));
323         tmp += sizeof(phdr);
324
325         /* Remove unwanted PT_NOTE program headers. */
326         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
327         *elfsz = *elfsz - i;
328         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
329
330         /* Modify e_phnum to reflect merged headers. */
331         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
332
333         return 0;
334 }
335
336 /* Merges all the PT_NOTE headers into one. */
337 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
338                                                 struct list_head *vc_list)
339 {
340         int i, nr_ptnote=0, rc=0;
341         char *tmp;
342         Elf32_Ehdr *ehdr_ptr;
343         Elf32_Phdr phdr, *phdr_ptr;
344         Elf32_Nhdr *nhdr_ptr;
345         u64 phdr_sz = 0, note_off;
346
347         ehdr_ptr = (Elf32_Ehdr *)elfptr;
348         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
349         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
350                 int j;
351                 void *notes_section;
352                 struct vmcore *new;
353                 u64 offset, max_sz, sz, real_sz = 0;
354                 if (phdr_ptr->p_type != PT_NOTE)
355                         continue;
356                 nr_ptnote++;
357                 max_sz = phdr_ptr->p_memsz;
358                 offset = phdr_ptr->p_offset;
359                 notes_section = kmalloc(max_sz, GFP_KERNEL);
360                 if (!notes_section)
361                         return -ENOMEM;
362                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
363                 if (rc < 0) {
364                         kfree(notes_section);
365                         return rc;
366                 }
367                 nhdr_ptr = notes_section;
368                 for (j = 0; j < max_sz; j += sz) {
369                         if (nhdr_ptr->n_namesz == 0)
370                                 break;
371                         sz = sizeof(Elf32_Nhdr) +
372                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
373                                 ((nhdr_ptr->n_descsz + 3) & ~3);
374                         real_sz += sz;
375                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
376                 }
377
378                 /* Add this contiguous chunk of notes section to vmcore list.*/
379                 new = get_new_element();
380                 if (!new) {
381                         kfree(notes_section);
382                         return -ENOMEM;
383                 }
384                 new->paddr = phdr_ptr->p_offset;
385                 new->size = real_sz;
386                 list_add_tail(&new->list, vc_list);
387                 phdr_sz += real_sz;
388                 kfree(notes_section);
389         }
390
391         /* Prepare merged PT_NOTE program header. */
392         phdr.p_type    = PT_NOTE;
393         phdr.p_flags   = 0;
394         note_off = sizeof(Elf32_Ehdr) +
395                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
396         phdr.p_offset  = note_off;
397         phdr.p_vaddr   = phdr.p_paddr = 0;
398         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
399         phdr.p_align   = 0;
400
401         /* Add merged PT_NOTE program header*/
402         tmp = elfptr + sizeof(Elf32_Ehdr);
403         memcpy(tmp, &phdr, sizeof(phdr));
404         tmp += sizeof(phdr);
405
406         /* Remove unwanted PT_NOTE program headers. */
407         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
408         *elfsz = *elfsz - i;
409         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
410
411         /* Modify e_phnum to reflect merged headers. */
412         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
413
414         return 0;
415 }
416
417 /* Add memory chunks represented by program headers to vmcore list. Also update
418  * the new offset fields of exported program headers. */
419 static int __init process_ptload_program_headers_elf64(char *elfptr,
420                                                 size_t elfsz,
421                                                 struct list_head *vc_list)
422 {
423         int i;
424         Elf64_Ehdr *ehdr_ptr;
425         Elf64_Phdr *phdr_ptr;
426         loff_t vmcore_off;
427         struct vmcore *new;
428
429         ehdr_ptr = (Elf64_Ehdr *)elfptr;
430         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
431
432         /* First program header is PT_NOTE header. */
433         vmcore_off = sizeof(Elf64_Ehdr) +
434                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
435                         phdr_ptr->p_memsz; /* Note sections */
436
437         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
438                 if (phdr_ptr->p_type != PT_LOAD)
439                         continue;
440
441                 /* Add this contiguous chunk of memory to vmcore list.*/
442                 new = get_new_element();
443                 if (!new)
444                         return -ENOMEM;
445                 new->paddr = phdr_ptr->p_offset;
446                 new->size = phdr_ptr->p_memsz;
447                 list_add_tail(&new->list, vc_list);
448
449                 /* Update the program header offset. */
450                 phdr_ptr->p_offset = vmcore_off;
451                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
452         }
453         return 0;
454 }
455
456 static int __init process_ptload_program_headers_elf32(char *elfptr,
457                                                 size_t elfsz,
458                                                 struct list_head *vc_list)
459 {
460         int i;
461         Elf32_Ehdr *ehdr_ptr;
462         Elf32_Phdr *phdr_ptr;
463         loff_t vmcore_off;
464         struct vmcore *new;
465
466         ehdr_ptr = (Elf32_Ehdr *)elfptr;
467         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
468
469         /* First program header is PT_NOTE header. */
470         vmcore_off = sizeof(Elf32_Ehdr) +
471                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
472                         phdr_ptr->p_memsz; /* Note sections */
473
474         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
475                 if (phdr_ptr->p_type != PT_LOAD)
476                         continue;
477
478                 /* Add this contiguous chunk of memory to vmcore list.*/
479                 new = get_new_element();
480                 if (!new)
481                         return -ENOMEM;
482                 new->paddr = phdr_ptr->p_offset;
483                 new->size = phdr_ptr->p_memsz;
484                 list_add_tail(&new->list, vc_list);
485
486                 /* Update the program header offset */
487                 phdr_ptr->p_offset = vmcore_off;
488                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
489         }
490         return 0;
491 }
492
493 /* Sets offset fields of vmcore elements. */
494 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
495                                                 struct list_head *vc_list)
496 {
497         loff_t vmcore_off;
498         Elf64_Ehdr *ehdr_ptr;
499         struct vmcore *m;
500
501         ehdr_ptr = (Elf64_Ehdr *)elfptr;
502
503         /* Skip Elf header and program headers. */
504         vmcore_off = sizeof(Elf64_Ehdr) +
505                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
506
507         list_for_each_entry(m, vc_list, list) {
508                 m->offset = vmcore_off;
509                 vmcore_off += m->size;
510         }
511 }
512
513 /* Sets offset fields of vmcore elements. */
514 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
515                                                 struct list_head *vc_list)
516 {
517         loff_t vmcore_off;
518         Elf32_Ehdr *ehdr_ptr;
519         struct vmcore *m;
520
521         ehdr_ptr = (Elf32_Ehdr *)elfptr;
522
523         /* Skip Elf header and program headers. */
524         vmcore_off = sizeof(Elf32_Ehdr) +
525                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
526
527         list_for_each_entry(m, vc_list, list) {
528                 m->offset = vmcore_off;
529                 vmcore_off += m->size;
530         }
531 }
532
533 static int __init parse_crash_elf64_headers(void)
534 {
535         int rc=0;
536         Elf64_Ehdr ehdr;
537         u64 addr;
538
539         addr = elfcorehdr_addr;
540
541         /* Read Elf header */
542         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
543         if (rc < 0)
544                 return rc;
545
546         /* Do some basic Verification. */
547         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
548                 (ehdr.e_type != ET_CORE) ||
549                 !vmcore_elf64_check_arch(&ehdr) ||
550                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
551                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
552                 ehdr.e_version != EV_CURRENT ||
553                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
554                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
555                 ehdr.e_phnum == 0) {
556                 printk(KERN_WARNING "Warning: Core image elf header is not"
557                                         "sane\n");
558                 return -EINVAL;
559         }
560
561         /* Read in all elf headers. */
562         elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
563         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
564         if (!elfcorebuf)
565                 return -ENOMEM;
566         addr = elfcorehdr_addr;
567         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
568         if (rc < 0) {
569                 kfree(elfcorebuf);
570                 return rc;
571         }
572
573         /* Merge all PT_NOTE headers into one. */
574         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
575         if (rc) {
576                 kfree(elfcorebuf);
577                 return rc;
578         }
579         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
580                                                         &vmcore_list);
581         if (rc) {
582                 kfree(elfcorebuf);
583                 return rc;
584         }
585         set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
586         return 0;
587 }
588
589 static int __init parse_crash_elf32_headers(void)
590 {
591         int rc=0;
592         Elf32_Ehdr ehdr;
593         u64 addr;
594
595         addr = elfcorehdr_addr;
596
597         /* Read Elf header */
598         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
599         if (rc < 0)
600                 return rc;
601
602         /* Do some basic Verification. */
603         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
604                 (ehdr.e_type != ET_CORE) ||
605                 !elf_check_arch(&ehdr) ||
606                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
607                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
608                 ehdr.e_version != EV_CURRENT ||
609                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
610                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
611                 ehdr.e_phnum == 0) {
612                 printk(KERN_WARNING "Warning: Core image elf header is not"
613                                         "sane\n");
614                 return -EINVAL;
615         }
616
617         /* Read in all elf headers. */
618         elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
619         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
620         if (!elfcorebuf)
621                 return -ENOMEM;
622         addr = elfcorehdr_addr;
623         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
624         if (rc < 0) {
625                 kfree(elfcorebuf);
626                 return rc;
627         }
628
629         /* Merge all PT_NOTE headers into one. */
630         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
631         if (rc) {
632                 kfree(elfcorebuf);
633                 return rc;
634         }
635         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
636                                                                 &vmcore_list);
637         if (rc) {
638                 kfree(elfcorebuf);
639                 return rc;
640         }
641         set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
642         return 0;
643 }
644
645 static int __init parse_crash_elf_headers(void)
646 {
647         unsigned char e_ident[EI_NIDENT];
648         u64 addr;
649         int rc=0;
650
651         addr = elfcorehdr_addr;
652         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
653         if (rc < 0)
654                 return rc;
655         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
656                 printk(KERN_WARNING "Warning: Core image elf header"
657                                         " not found\n");
658                 return -EINVAL;
659         }
660
661         if (e_ident[EI_CLASS] == ELFCLASS64) {
662                 rc = parse_crash_elf64_headers();
663                 if (rc)
664                         return rc;
665
666                 /* Determine vmcore size. */
667                 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
668         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
669                 rc = parse_crash_elf32_headers();
670                 if (rc)
671                         return rc;
672
673                 /* Determine vmcore size. */
674                 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
675         } else {
676                 printk(KERN_WARNING "Warning: Core image elf header is not"
677                                         " sane\n");
678                 return -EINVAL;
679         }
680         return 0;
681 }
682
683 /* Init function for vmcore module. */
684 static int __init vmcore_init(void)
685 {
686         int rc = 0;
687
688         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
689         if (!(is_vmcore_usable()))
690                 return rc;
691         rc = parse_crash_elf_headers();
692         if (rc) {
693                 printk(KERN_WARNING "Kdump: vmcore not initialized\n");
694                 return rc;
695         }
696
697         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
698         if (proc_vmcore)
699                 proc_vmcore->size = vmcore_size;
700         return 0;
701 }
702 module_init(vmcore_init)
703
704 /* Cleanup function for vmcore module. */
705 void vmcore_cleanup(void)
706 {
707         struct list_head *pos, *next;
708
709         if (proc_vmcore) {
710                 remove_proc_entry(proc_vmcore->name, proc_vmcore->parent);
711                 proc_vmcore = NULL;
712         }
713
714         /* clear the vmcore list. */
715         list_for_each_safe(pos, next, &vmcore_list) {
716                 struct vmcore *m;
717
718                 m = list_entry(pos, struct vmcore, list);
719                 list_del(&m->list);
720                 kfree(m);
721         }
722         kfree(elfcorebuf);
723         elfcorebuf = NULL;
724 }
725 EXPORT_SYMBOL_GPL(vmcore_cleanup);