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