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