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