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/a.out.h>
  14 #include <linux/elf.h>
  15 #include <linux/elfcore.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 /* Stores the physical address of elf header of crash image. */
  37 unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
  38
  39 struct proc_dir_entry *proc_vmcore = NULL;
  40
  41 /* Reads a page from the oldmem device from given offset. */
  42 static ssize_t read_from_oldmem(char *buf, size_t count,
  43                                 u64 *ppos, int userbuf)
  44 {
  45         unsigned long pfn, offset;
  46         size_t nr_bytes;
  47         ssize_t read = 0, tmp;
  48
  49         if (!count)
  50                 return 0;
  51
  52         offset = (unsigned long)(*ppos % PAGE_SIZE);
  53         pfn = (unsigned long)(*ppos / PAGE_SIZE);
  54         if (pfn > saved_max_pfn)
  55                 return -EINVAL;
  56
  57         do {
  58                 if (count > (PAGE_SIZE - offset))
  59                         nr_bytes = PAGE_SIZE - offset;
  60                 else
  61                         nr_bytes = count;
  62
  63                 tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf);
  64                 if (tmp < 0)
  65                         return tmp;
  66                 *ppos += nr_bytes;
  67                 count -= nr_bytes;
  68                 buf += nr_bytes;
  69                 read += nr_bytes;
  70                 ++pfn;
  71                 offset = 0;
  72         } while (count);
  73
  74         return read;
  75 }
  76
  77 /* Maps vmcore file offset to respective physical address in memroy. */
  78 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
  79                                         struct vmcore **m_ptr)
  80 {
  81         struct vmcore *m;
  82         u64 paddr;
  83
  84         list_for_each_entry(m, vc_list, list) {
  85                 u64 start, end;
  86                 start = m->offset;
  87                 end = m->offset + m->size - 1;
  88                 if (offset >= start && offset <= end) {
  89                         paddr = m->paddr + offset - start;
  90                         *m_ptr = m;
  91                         return paddr;
  92                 }
  93         }
  94         *m_ptr = NULL;
  95         return 0;
  96 }
  97
  98 /* Read from the ELF header and then the crash dump. On error, negative value is
  99  * returned otherwise number of bytes read are returned.
 100  */
 101 static ssize_t read_vmcore(struct file *file, char __user *buffer,
 102                                 size_t buflen, loff_t *fpos)
 103 {
 104         ssize_t acc = 0, tmp;
 105         size_t tsz;
 106         u64 start, nr_bytes;
 107         struct vmcore *curr_m = NULL;
 108
 109         if (buflen == 0 || *fpos >= vmcore_size)
 110                 return 0;
 111
 112         /* trim buflen to not go beyond EOF */
 113         if (buflen > vmcore_size - *fpos)
 114                 buflen = vmcore_size - *fpos;
 115
 116         /* Read ELF core header */
 117         if (*fpos < elfcorebuf_sz) {
 118                 tsz = elfcorebuf_sz - *fpos;
 119                 if (buflen < tsz)
 120                         tsz = buflen;
 121                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
 122                         return -EFAULT;
 123                 buflen -= tsz;
 124                 *fpos += tsz;
 125                 buffer += tsz;
 126                 acc += tsz;
 127
 128                 /* leave now if filled buffer already */
 129                 if (buflen == 0)
 130                         return acc;
 131         }
 132
 133         start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
 134         if (!curr_m)
 135                 return -EINVAL;
 136         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 137                 tsz = buflen;
 138
 139         /* Calculate left bytes in current memory segment. */
 140         nr_bytes = (curr_m->size - (start - curr_m->paddr));
 141         if (tsz > nr_bytes)
 142                 tsz = nr_bytes;
 143
 144         while (buflen) {
 145                 tmp = read_from_oldmem(buffer, tsz, &start, 1);
 146                 if (tmp < 0)
 147                         return tmp;
 148                 buflen -= tsz;
 149                 *fpos += tsz;
 150                 buffer += tsz;
 151                 acc += tsz;
 152                 if (start >= (curr_m->paddr + curr_m->size)) {
 153                         if (curr_m->list.next == &vmcore_list)
 154                                 return acc;     /*EOF*/
 155                         curr_m = list_entry(curr_m->list.next,
 156                                                 struct vmcore, list);
 157                         start = curr_m->paddr;
 158                 }
 159                 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 160                         tsz = buflen;
 161                 /* Calculate left bytes in current memory segment. */
 162                 nr_bytes = (curr_m->size - (start - curr_m->paddr));
 163                 if (tsz > nr_bytes)
 164                         tsz = nr_bytes;
 165         }
 166         return acc;
 167 }
 168
 169 static int open_vmcore(struct inode *inode, struct file *filp)
 170 {
 171         return 0;
 172 }
 173
 174 const struct file_operations proc_vmcore_operations = {
 175         .read           = read_vmcore,
 176         .open           = open_vmcore,
 177 };
 178
 179 static struct vmcore* __init get_new_element(void)
 180 {
 181         struct vmcore *p;
 182
 183         p = kmalloc(sizeof(*p), GFP_KERNEL);
 184         if (p)
 185                 memset(p, 0, sizeof(*p));
 186         return p;
 187 }
 188
 189 static u64 __init get_vmcore_size_elf64(char *elfptr)
 190 {
 191         int i;
 192         u64 size;
 193         Elf64_Ehdr *ehdr_ptr;
 194         Elf64_Phdr *phdr_ptr;
 195
 196         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 197         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 198         size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_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 static u64 __init get_vmcore_size_elf32(char *elfptr)
 207 {
 208         int i;
 209         u64 size;
 210         Elf32_Ehdr *ehdr_ptr;
 211         Elf32_Phdr *phdr_ptr;
 212
 213         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 214         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 215         size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
 216         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 217                 size += phdr_ptr->p_memsz;
 218                 phdr_ptr++;
 219         }
 220         return size;
 221 }
 222
 223 /* Merges all the PT_NOTE headers into one. */
 224 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 225                                                 struct list_head *vc_list)
 226 {
 227         int i, nr_ptnote=0, rc=0;
 228         char *tmp;
 229         Elf64_Ehdr *ehdr_ptr;
 230         Elf64_Phdr phdr, *phdr_ptr;
 231         Elf64_Nhdr *nhdr_ptr;
 232         u64 phdr_sz = 0, note_off;
 233
 234         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 235         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 236         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 237                 int j;
 238                 void *notes_section;
 239                 struct vmcore *new;
 240                 u64 offset, max_sz, sz, real_sz = 0;
 241                 if (phdr_ptr->p_type != PT_NOTE)
 242                         continue;
 243                 nr_ptnote++;
 244                 max_sz = phdr_ptr->p_memsz;
 245                 offset = phdr_ptr->p_offset;
 246                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 247                 if (!notes_section)
 248                         return -ENOMEM;
 249                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 250                 if (rc < 0) {
 251                         kfree(notes_section);
 252                         return rc;
 253                 }
 254                 nhdr_ptr = notes_section;
 255                 for (j = 0; j < max_sz; j += sz) {
 256                         if (nhdr_ptr->n_namesz == 0)
 257                                 break;
 258                         sz = sizeof(Elf64_Nhdr) +
 259                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 260                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 261                         real_sz += sz;
 262                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 263                 }
 264
 265                 /* Add this contiguous chunk of notes section to vmcore list.*/
 266                 new = get_new_element();
 267                 if (!new) {
 268                         kfree(notes_section);
 269                         return -ENOMEM;
 270                 }
 271                 new->paddr = phdr_ptr->p_offset;
 272                 new->size = real_sz;
 273                 list_add_tail(&new->list, vc_list);
 274                 phdr_sz += real_sz;
 275                 kfree(notes_section);
 276         }
 277
 278         /* Prepare merged PT_NOTE program header. */
 279         phdr.p_type    = PT_NOTE;
 280         phdr.p_flags   = 0;
 281         note_off = sizeof(Elf64_Ehdr) +
 282                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 283         phdr.p_offset  = note_off;
 284         phdr.p_vaddr   = phdr.p_paddr = 0;
 285         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 286         phdr.p_align   = 0;
 287
 288         /* Add merged PT_NOTE program header*/
 289         tmp = elfptr + sizeof(Elf64_Ehdr);
 290         memcpy(tmp, &phdr, sizeof(phdr));
 291         tmp += sizeof(phdr);
 292
 293         /* Remove unwanted PT_NOTE program headers. */
 294         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 295         *elfsz = *elfsz - i;
 296         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 297
 298         /* Modify e_phnum to reflect merged headers. */
 299         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 300
 301         return 0;
 302 }
 303
 304 /* Merges all the PT_NOTE headers into one. */
 305 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 306                                                 struct list_head *vc_list)
 307 {
 308         int i, nr_ptnote=0, rc=0;
 309         char *tmp;
 310         Elf32_Ehdr *ehdr_ptr;
 311         Elf32_Phdr phdr, *phdr_ptr;
 312         Elf32_Nhdr *nhdr_ptr;
 313         u64 phdr_sz = 0, note_off;
 314
 315         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 316         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 317         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 318                 int j;
 319                 void *notes_section;
 320                 struct vmcore *new;
 321                 u64 offset, max_sz, sz, real_sz = 0;
 322                 if (phdr_ptr->p_type != PT_NOTE)
 323                         continue;
 324                 nr_ptnote++;
 325                 max_sz = phdr_ptr->p_memsz;
 326                 offset = phdr_ptr->p_offset;
 327                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 328                 if (!notes_section)
 329                         return -ENOMEM;
 330                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 331                 if (rc < 0) {
 332                         kfree(notes_section);
 333                         return rc;
 334                 }
 335                 nhdr_ptr = notes_section;
 336                 for (j = 0; j < max_sz; j += sz) {
 337                         if (nhdr_ptr->n_namesz == 0)
 338                                 break;
 339                         sz = sizeof(Elf32_Nhdr) +
 340                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 341                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 342                         real_sz += sz;
 343                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 344                 }
 345
 346                 /* Add this contiguous chunk of notes section to vmcore list.*/
 347                 new = get_new_element();
 348                 if (!new) {
 349                         kfree(notes_section);
 350                         return -ENOMEM;
 351                 }
 352                 new->paddr = phdr_ptr->p_offset;
 353                 new->size = real_sz;
 354                 list_add_tail(&new->list, vc_list);
 355                 phdr_sz += real_sz;
 356                 kfree(notes_section);
 357         }
 358
 359         /* Prepare merged PT_NOTE program header. */
 360         phdr.p_type    = PT_NOTE;
 361         phdr.p_flags   = 0;
 362         note_off = sizeof(Elf32_Ehdr) +
 363                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
 364         phdr.p_offset  = note_off;
 365         phdr.p_vaddr   = phdr.p_paddr = 0;
 366         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 367         phdr.p_align   = 0;
 368
 369         /* Add merged PT_NOTE program header*/
 370         tmp = elfptr + sizeof(Elf32_Ehdr);
 371         memcpy(tmp, &phdr, sizeof(phdr));
 372         tmp += sizeof(phdr);
 373
 374         /* Remove unwanted PT_NOTE program headers. */
 375         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
 376         *elfsz = *elfsz - i;
 377         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
 378
 379         /* Modify e_phnum to reflect merged headers. */
 380         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 381
 382         return 0;
 383 }
 384
 385 /* Add memory chunks represented by program headers to vmcore list. Also update
 386  * the new offset fields of exported program headers. */
 387 static int __init process_ptload_program_headers_elf64(char *elfptr,
 388                                                 size_t elfsz,
 389                                                 struct list_head *vc_list)
 390 {
 391         int i;
 392         Elf64_Ehdr *ehdr_ptr;
 393         Elf64_Phdr *phdr_ptr;
 394         loff_t vmcore_off;
 395         struct vmcore *new;
 396
 397         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 398         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 399
 400         /* First program header is PT_NOTE header. */
 401         vmcore_off = sizeof(Elf64_Ehdr) +
 402                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
 403                         phdr_ptr->p_memsz; /* Note sections */
 404
 405         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 406                 if (phdr_ptr->p_type != PT_LOAD)
 407                         continue;
 408
 409                 /* Add this contiguous chunk of memory to vmcore list.*/
 410                 new = get_new_element();
 411                 if (!new)
 412                         return -ENOMEM;
 413                 new->paddr = phdr_ptr->p_offset;
 414                 new->size = phdr_ptr->p_memsz;
 415                 list_add_tail(&new->list, vc_list);
 416
 417                 /* Update the program header offset. */
 418                 phdr_ptr->p_offset = vmcore_off;
 419                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 420         }
 421         return 0;
 422 }
 423
 424 static int __init process_ptload_program_headers_elf32(char *elfptr,
 425                                                 size_t elfsz,
 426                                                 struct list_head *vc_list)
 427 {
 428         int i;
 429         Elf32_Ehdr *ehdr_ptr;
 430         Elf32_Phdr *phdr_ptr;
 431         loff_t vmcore_off;
 432         struct vmcore *new;
 433
 434         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 435         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
 436
 437         /* First program header is PT_NOTE header. */
 438         vmcore_off = sizeof(Elf32_Ehdr) +
 439                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
 440                         phdr_ptr->p_memsz; /* Note sections */
 441
 442         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 443                 if (phdr_ptr->p_type != PT_LOAD)
 444                         continue;
 445
 446                 /* Add this contiguous chunk of memory to vmcore list.*/
 447                 new = get_new_element();
 448                 if (!new)
 449                         return -ENOMEM;
 450                 new->paddr = phdr_ptr->p_offset;
 451                 new->size = phdr_ptr->p_memsz;
 452                 list_add_tail(&new->list, vc_list);
 453
 454                 /* Update the program header offset */
 455                 phdr_ptr->p_offset = vmcore_off;
 456                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 457         }
 458         return 0;
 459 }
 460
 461 /* Sets offset fields of vmcore elements. */
 462 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
 463                                                 struct list_head *vc_list)
 464 {
 465         loff_t vmcore_off;
 466         Elf64_Ehdr *ehdr_ptr;
 467         struct vmcore *m;
 468
 469         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 470
 471         /* Skip Elf header and program headers. */
 472         vmcore_off = sizeof(Elf64_Ehdr) +
 473                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
 474
 475         list_for_each_entry(m, vc_list, list) {
 476                 m->offset = vmcore_off;
 477                 vmcore_off += m->size;
 478         }
 479 }
 480
 481 /* Sets offset fields of vmcore elements. */
 482 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
 483                                                 struct list_head *vc_list)
 484 {
 485         loff_t vmcore_off;
 486         Elf32_Ehdr *ehdr_ptr;
 487         struct vmcore *m;
 488
 489         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 490
 491         /* Skip Elf header and program headers. */
 492         vmcore_off = sizeof(Elf32_Ehdr) +
 493                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
 494
 495         list_for_each_entry(m, vc_list, list) {
 496                 m->offset = vmcore_off;
 497                 vmcore_off += m->size;
 498         }
 499 }
 500
 501 static int __init parse_crash_elf64_headers(void)
 502 {
 503         int rc=0;
 504         Elf64_Ehdr ehdr;
 505         u64 addr;
 506
 507         addr = elfcorehdr_addr;
 508
 509         /* Read Elf header */
 510         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
 511         if (rc < 0)
 512                 return rc;
 513
 514         /* Do some basic Verification. */
 515         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 516                 (ehdr.e_type != ET_CORE) ||
 517                 !elf_check_arch(&ehdr) ||
 518                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
 519                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 520                 ehdr.e_version != EV_CURRENT ||
 521                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
 522                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
 523                 ehdr.e_phnum == 0) {
 524                 printk(KERN_WARNING "Warning: Core image elf header is not"
 525                                         "sane\n");
 526                 return -EINVAL;
 527         }
 528
 529         /* Read in all elf headers. */
 530         elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
 531         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 532         if (!elfcorebuf)
 533                 return -ENOMEM;
 534         addr = elfcorehdr_addr;
 535         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 536         if (rc < 0) {
 537                 kfree(elfcorebuf);
 538                 return rc;
 539         }
 540
 541         /* Merge all PT_NOTE headers into one. */
 542         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 543         if (rc) {
 544                 kfree(elfcorebuf);
 545                 return rc;
 546         }
 547         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
 548                                                         &vmcore_list);
 549         if (rc) {
 550                 kfree(elfcorebuf);
 551                 return rc;
 552         }
 553         set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
 554         return 0;
 555 }
 556
 557 static int __init parse_crash_elf32_headers(void)
 558 {
 559         int rc=0;
 560         Elf32_Ehdr ehdr;
 561         u64 addr;
 562
 563         addr = elfcorehdr_addr;
 564
 565         /* Read Elf header */
 566         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
 567         if (rc < 0)
 568                 return rc;
 569
 570         /* Do some basic Verification. */
 571         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 572                 (ehdr.e_type != ET_CORE) ||
 573                 !elf_check_arch(&ehdr) ||
 574                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
 575                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 576                 ehdr.e_version != EV_CURRENT ||
 577                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
 578                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
 579                 ehdr.e_phnum == 0) {
 580                 printk(KERN_WARNING "Warning: Core image elf header is not"
 581                                         "sane\n");
 582                 return -EINVAL;
 583         }
 584
 585         /* Read in all elf headers. */
 586         elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
 587         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 588         if (!elfcorebuf)
 589                 return -ENOMEM;
 590         addr = elfcorehdr_addr;
 591         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 592         if (rc < 0) {
 593                 kfree(elfcorebuf);
 594                 return rc;
 595         }
 596
 597         /* Merge all PT_NOTE headers into one. */
 598         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 599         if (rc) {
 600                 kfree(elfcorebuf);
 601                 return rc;
 602         }
 603         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
 604                                                                 &vmcore_list);
 605         if (rc) {
 606                 kfree(elfcorebuf);
 607                 return rc;
 608         }
 609         set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
 610         return 0;
 611 }
 612
 613 static int __init parse_crash_elf_headers(void)
 614 {
 615         unsigned char e_ident[EI_NIDENT];
 616         u64 addr;
 617         int rc=0;
 618
 619         addr = elfcorehdr_addr;
 620         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
 621         if (rc < 0)
 622                 return rc;
 623         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
 624                 printk(KERN_WARNING "Warning: Core image elf header"
 625                                         " not found\n");
 626                 return -EINVAL;
 627         }
 628
 629         if (e_ident[EI_CLASS] == ELFCLASS64) {
 630                 rc = parse_crash_elf64_headers();
 631                 if (rc)
 632                         return rc;
 633
 634                 /* Determine vmcore size. */
 635                 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
 636         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
 637                 rc = parse_crash_elf32_headers();
 638                 if (rc)
 639                         return rc;
 640
 641                 /* Determine vmcore size. */
 642                 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
 643         } else {
 644                 printk(KERN_WARNING "Warning: Core image elf header is not"
 645                                         " sane\n");
 646                 return -EINVAL;
 647         }
 648         return 0;
 649 }
 650
 651 /* Init function for vmcore module. */
 652 static int __init vmcore_init(void)
 653 {
 654         int rc = 0;
 655
 656         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
 657         if (!(elfcorehdr_addr < ELFCORE_ADDR_MAX))
 658                 return rc;
 659         rc = parse_crash_elf_headers();
 660         if (rc) {
 661                 printk(KERN_WARNING "Kdump: vmcore not initialized\n");
 662                 return rc;
 663         }
 664
 665         /* Initialize /proc/vmcore size if proc is already up. */
 666         if (proc_vmcore)
 667                 proc_vmcore->size = vmcore_size;
 668         return 0;
 669 }
 670 module_init(vmcore_init)