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