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         .llseek         = default_llseek,
 167 };
 168
 169 static struct vmcore* __init get_new_element(void)
 170 {
 171         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
 172 }
 173
 174 static u64 __init get_vmcore_size_elf64(char *elfptr)
 175 {
 176         int i;
 177         u64 size;
 178         Elf64_Ehdr *ehdr_ptr;
 179         Elf64_Phdr *phdr_ptr;
 180
 181         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 182         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 183         size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
 184         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 185                 size += phdr_ptr->p_memsz;
 186                 phdr_ptr++;
 187         }
 188         return size;
 189 }
 190
 191 static u64 __init get_vmcore_size_elf32(char *elfptr)
 192 {
 193         int i;
 194         u64 size;
 195         Elf32_Ehdr *ehdr_ptr;
 196         Elf32_Phdr *phdr_ptr;
 197
 198         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 199         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 200         size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
 201         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 202                 size += phdr_ptr->p_memsz;
 203                 phdr_ptr++;
 204         }
 205         return size;
 206 }
 207
 208 /* Merges all the PT_NOTE headers into one. */
 209 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 210                                                 struct list_head *vc_list)
 211 {
 212         int i, nr_ptnote=0, rc=0;
 213         char *tmp;
 214         Elf64_Ehdr *ehdr_ptr;
 215         Elf64_Phdr phdr, *phdr_ptr;
 216         Elf64_Nhdr *nhdr_ptr;
 217         u64 phdr_sz = 0, note_off;
 218
 219         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 220         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 221         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 222                 int j;
 223                 void *notes_section;
 224                 struct vmcore *new;
 225                 u64 offset, max_sz, sz, real_sz = 0;
 226                 if (phdr_ptr->p_type != PT_NOTE)
 227                         continue;
 228                 nr_ptnote++;
 229                 max_sz = phdr_ptr->p_memsz;
 230                 offset = phdr_ptr->p_offset;
 231                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 232                 if (!notes_section)
 233                         return -ENOMEM;
 234                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 235                 if (rc < 0) {
 236                         kfree(notes_section);
 237                         return rc;
 238                 }
 239                 nhdr_ptr = notes_section;
 240                 for (j = 0; j < max_sz; j += sz) {
 241                         if (nhdr_ptr->n_namesz == 0)
 242                                 break;
 243                         sz = sizeof(Elf64_Nhdr) +
 244                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 245                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 246                         real_sz += sz;
 247                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 248                 }
 249
 250                 /* Add this contiguous chunk of notes section to vmcore list.*/
 251                 new = get_new_element();
 252                 if (!new) {
 253                         kfree(notes_section);
 254                         return -ENOMEM;
 255                 }
 256                 new->paddr = phdr_ptr->p_offset;
 257                 new->size = real_sz;
 258                 list_add_tail(&new->list, vc_list);
 259                 phdr_sz += real_sz;
 260                 kfree(notes_section);
 261         }
 262
 263         /* Prepare merged PT_NOTE program header. */
 264         phdr.p_type    = PT_NOTE;
 265         phdr.p_flags   = 0;
 266         note_off = sizeof(Elf64_Ehdr) +
 267                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 268         phdr.p_offset  = note_off;
 269         phdr.p_vaddr   = phdr.p_paddr = 0;
 270         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 271         phdr.p_align   = 0;
 272
 273         /* Add merged PT_NOTE program header*/
 274         tmp = elfptr + sizeof(Elf64_Ehdr);
 275         memcpy(tmp, &phdr, sizeof(phdr));
 276         tmp += sizeof(phdr);
 277
 278         /* Remove unwanted PT_NOTE program headers. */
 279         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 280         *elfsz = *elfsz - i;
 281         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 282
 283         /* Modify e_phnum to reflect merged headers. */
 284         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 285
 286         return 0;
 287 }
 288
 289 /* Merges all the PT_NOTE headers into one. */
 290 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 291                                                 struct list_head *vc_list)
 292 {
 293         int i, nr_ptnote=0, rc=0;
 294         char *tmp;
 295         Elf32_Ehdr *ehdr_ptr;
 296         Elf32_Phdr phdr, *phdr_ptr;
 297         Elf32_Nhdr *nhdr_ptr;
 298         u64 phdr_sz = 0, note_off;
 299
 300         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 301         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 302         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 303                 int j;
 304                 void *notes_section;
 305                 struct vmcore *new;
 306                 u64 offset, max_sz, sz, real_sz = 0;
 307                 if (phdr_ptr->p_type != PT_NOTE)
 308                         continue;
 309                 nr_ptnote++;
 310                 max_sz = phdr_ptr->p_memsz;
 311                 offset = phdr_ptr->p_offset;
 312                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 313                 if (!notes_section)
 314                         return -ENOMEM;
 315                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 316                 if (rc < 0) {
 317                         kfree(notes_section);
 318                         return rc;
 319                 }
 320                 nhdr_ptr = notes_section;
 321                 for (j = 0; j < max_sz; j += sz) {
 322                         if (nhdr_ptr->n_namesz == 0)
 323                                 break;
 324                         sz = sizeof(Elf32_Nhdr) +
 325                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 326                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 327                         real_sz += sz;
 328                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 329                 }
 330
 331                 /* Add this contiguous chunk of notes section to vmcore list.*/
 332                 new = get_new_element();
 333                 if (!new) {
 334                         kfree(notes_section);
 335                         return -ENOMEM;
 336                 }
 337                 new->paddr = phdr_ptr->p_offset;
 338                 new->size = real_sz;
 339                 list_add_tail(&new->list, vc_list);
 340                 phdr_sz += real_sz;
 341                 kfree(notes_section);
 342         }
 343
 344         /* Prepare merged PT_NOTE program header. */
 345         phdr.p_type    = PT_NOTE;
 346         phdr.p_flags   = 0;
 347         note_off = sizeof(Elf32_Ehdr) +
 348                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
 349         phdr.p_offset  = note_off;
 350         phdr.p_vaddr   = phdr.p_paddr = 0;
 351         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 352         phdr.p_align   = 0;
 353
 354         /* Add merged PT_NOTE program header*/
 355         tmp = elfptr + sizeof(Elf32_Ehdr);
 356         memcpy(tmp, &phdr, sizeof(phdr));
 357         tmp += sizeof(phdr);
 358
 359         /* Remove unwanted PT_NOTE program headers. */
 360         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
 361         *elfsz = *elfsz - i;
 362         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
 363
 364         /* Modify e_phnum to reflect merged headers. */
 365         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 366
 367         return 0;
 368 }
 369
 370 /* Add memory chunks represented by program headers to vmcore list. Also update
 371  * the new offset fields of exported program headers. */
 372 static int __init process_ptload_program_headers_elf64(char *elfptr,
 373                                                 size_t elfsz,
 374                                                 struct list_head *vc_list)
 375 {
 376         int i;
 377         Elf64_Ehdr *ehdr_ptr;
 378         Elf64_Phdr *phdr_ptr;
 379         loff_t vmcore_off;
 380         struct vmcore *new;
 381
 382         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 383         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 384
 385         /* First program header is PT_NOTE header. */
 386         vmcore_off = sizeof(Elf64_Ehdr) +
 387                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
 388                         phdr_ptr->p_memsz; /* Note sections */
 389
 390         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 391                 if (phdr_ptr->p_type != PT_LOAD)
 392                         continue;
 393
 394                 /* Add this contiguous chunk of memory to vmcore list.*/
 395                 new = get_new_element();
 396                 if (!new)
 397                         return -ENOMEM;
 398                 new->paddr = phdr_ptr->p_offset;
 399                 new->size = phdr_ptr->p_memsz;
 400                 list_add_tail(&new->list, vc_list);
 401
 402                 /* Update the program header offset. */
 403                 phdr_ptr->p_offset = vmcore_off;
 404                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 405         }
 406         return 0;
 407 }
 408
 409 static int __init process_ptload_program_headers_elf32(char *elfptr,
 410                                                 size_t elfsz,
 411                                                 struct list_head *vc_list)
 412 {
 413         int i;
 414         Elf32_Ehdr *ehdr_ptr;
 415         Elf32_Phdr *phdr_ptr;
 416         loff_t vmcore_off;
 417         struct vmcore *new;
 418
 419         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 420         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
 421
 422         /* First program header is PT_NOTE header. */
 423         vmcore_off = sizeof(Elf32_Ehdr) +
 424                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
 425                         phdr_ptr->p_memsz; /* Note sections */
 426
 427         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 428                 if (phdr_ptr->p_type != PT_LOAD)
 429                         continue;
 430
 431                 /* Add this contiguous chunk of memory to vmcore list.*/
 432                 new = get_new_element();
 433                 if (!new)
 434                         return -ENOMEM;
 435                 new->paddr = phdr_ptr->p_offset;
 436                 new->size = phdr_ptr->p_memsz;
 437                 list_add_tail(&new->list, vc_list);
 438
 439                 /* Update the program header offset */
 440                 phdr_ptr->p_offset = vmcore_off;
 441                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 442         }
 443         return 0;
 444 }
 445
 446 /* Sets offset fields of vmcore elements. */
 447 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
 448                                                 struct list_head *vc_list)
 449 {
 450         loff_t vmcore_off;
 451         Elf64_Ehdr *ehdr_ptr;
 452         struct vmcore *m;
 453
 454         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 455
 456         /* Skip Elf header and program headers. */
 457         vmcore_off = sizeof(Elf64_Ehdr) +
 458                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
 459
 460         list_for_each_entry(m, vc_list, list) {
 461                 m->offset = vmcore_off;
 462                 vmcore_off += m->size;
 463         }
 464 }
 465
 466 /* Sets offset fields of vmcore elements. */
 467 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
 468                                                 struct list_head *vc_list)
 469 {
 470         loff_t vmcore_off;
 471         Elf32_Ehdr *ehdr_ptr;
 472         struct vmcore *m;
 473
 474         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 475
 476         /* Skip Elf header and program headers. */
 477         vmcore_off = sizeof(Elf32_Ehdr) +
 478                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
 479
 480         list_for_each_entry(m, vc_list, list) {
 481                 m->offset = vmcore_off;
 482                 vmcore_off += m->size;
 483         }
 484 }
 485
 486 static int __init parse_crash_elf64_headers(void)
 487 {
 488         int rc=0;
 489         Elf64_Ehdr ehdr;
 490         u64 addr;
 491
 492         addr = elfcorehdr_addr;
 493
 494         /* Read Elf header */
 495         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
 496         if (rc < 0)
 497                 return rc;
 498
 499         /* Do some basic Verification. */
 500         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 501                 (ehdr.e_type != ET_CORE) ||
 502                 !vmcore_elf_check_arch(&ehdr) ||
 503                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
 504                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 505                 ehdr.e_version != EV_CURRENT ||
 506                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
 507                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
 508                 ehdr.e_phnum == 0) {
 509                 printk(KERN_WARNING "Warning: Core image elf header is not"
 510                                         "sane\n");
 511                 return -EINVAL;
 512         }
 513
 514         /* Read in all elf headers. */
 515         elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
 516         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 517         if (!elfcorebuf)
 518                 return -ENOMEM;
 519         addr = elfcorehdr_addr;
 520         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 521         if (rc < 0) {
 522                 kfree(elfcorebuf);
 523                 return rc;
 524         }
 525
 526         /* Merge all PT_NOTE headers into one. */
 527         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 528         if (rc) {
 529                 kfree(elfcorebuf);
 530                 return rc;
 531         }
 532         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
 533                                                         &vmcore_list);
 534         if (rc) {
 535                 kfree(elfcorebuf);
 536                 return rc;
 537         }
 538         set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
 539         return 0;
 540 }
 541
 542 static int __init parse_crash_elf32_headers(void)
 543 {
 544         int rc=0;
 545         Elf32_Ehdr ehdr;
 546         u64 addr;
 547
 548         addr = elfcorehdr_addr;
 549
 550         /* Read Elf header */
 551         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
 552         if (rc < 0)
 553                 return rc;
 554
 555         /* Do some basic Verification. */
 556         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 557                 (ehdr.e_type != ET_CORE) ||
 558                 !elf_check_arch(&ehdr) ||
 559                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
 560                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 561                 ehdr.e_version != EV_CURRENT ||
 562                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
 563                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
 564                 ehdr.e_phnum == 0) {
 565                 printk(KERN_WARNING "Warning: Core image elf header is not"
 566                                         "sane\n");
 567                 return -EINVAL;
 568         }
 569
 570         /* Read in all elf headers. */
 571         elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
 572         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 573         if (!elfcorebuf)
 574                 return -ENOMEM;
 575         addr = elfcorehdr_addr;
 576         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 577         if (rc < 0) {
 578                 kfree(elfcorebuf);
 579                 return rc;
 580         }
 581
 582         /* Merge all PT_NOTE headers into one. */
 583         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 584         if (rc) {
 585                 kfree(elfcorebuf);
 586                 return rc;
 587         }
 588         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
 589                                                                 &vmcore_list);
 590         if (rc) {
 591                 kfree(elfcorebuf);
 592                 return rc;
 593         }
 594         set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
 595         return 0;
 596 }
 597
 598 static int __init parse_crash_elf_headers(void)
 599 {
 600         unsigned char e_ident[EI_NIDENT];
 601         u64 addr;
 602         int rc=0;
 603
 604         addr = elfcorehdr_addr;
 605         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
 606         if (rc < 0)
 607                 return rc;
 608         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
 609                 printk(KERN_WARNING "Warning: Core image elf header"
 610                                         " not found\n");
 611                 return -EINVAL;
 612         }
 613
 614         if (e_ident[EI_CLASS] == ELFCLASS64) {
 615                 rc = parse_crash_elf64_headers();
 616                 if (rc)
 617                         return rc;
 618
 619                 /* Determine vmcore size. */
 620                 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
 621         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
 622                 rc = parse_crash_elf32_headers();
 623                 if (rc)
 624                         return rc;
 625
 626                 /* Determine vmcore size. */
 627                 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
 628         } else {
 629                 printk(KERN_WARNING "Warning: Core image elf header is not"
 630                                         " sane\n");
 631                 return -EINVAL;
 632         }
 633         return 0;
 634 }
 635
 636 /* Init function for vmcore module. */
 637 static int __init vmcore_init(void)
 638 {
 639         int rc = 0;
 640
 641         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
 642         if (!(is_vmcore_usable()))
 643                 return rc;
 644         rc = parse_crash_elf_headers();
 645         if (rc) {
 646                 printk(KERN_WARNING "Kdump: vmcore not initialized\n");
 647                 return rc;
 648         }
 649
 650         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
 651         if (proc_vmcore)
 652                 proc_vmcore->size = vmcore_size;
 653         return 0;
 654 }
 655 module_init(vmcore_init)