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