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