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/config.h>
  11 #include <linux/mm.h>
  12 #include <linux/proc_fs.h>
  13 #include <linux/user.h>
  14 #include <linux/a.out.h>
  15 #include <linux/elf.h>
  16 #include <linux/elfcore.h>
  17 #include <linux/highmem.h>
  18 #include <linux/bootmem.h>
  19 #include <linux/init.h>
  20 #include <linux/crash_dump.h>
  21 #include <linux/list.h>
  22 #include <asm/uaccess.h>
  23 #include <asm/io.h>
  24
  25 /* List representing chunks of contiguous memory areas and their offsets in
  26  * vmcore file.
  27  */
  28 static LIST_HEAD(vmcore_list);
  29
  30 /* Stores the pointer to the buffer containing kernel elf core headers. */
  31 static char *elfcorebuf;
  32 static size_t elfcorebuf_sz;
  33
  34 /* Total size of vmcore file. */
  35 static u64 vmcore_size;
  36
  37 /* Stores the physical address of elf header of crash image. */
  38 unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
  39
  40 struct proc_dir_entry *proc_vmcore = NULL;
  41
  42 /* Reads a page from the oldmem device from given offset. */
  43 static ssize_t read_from_oldmem(char *buf, size_t count,
  44                                 u64 *ppos, int userbuf)
  45 {
  46         unsigned long pfn, offset;
  47         size_t nr_bytes;
  48         ssize_t read = 0, tmp;
  49
  50         if (!count)
  51                 return 0;
  52
  53         offset = (unsigned long)(*ppos % PAGE_SIZE);
  54         pfn = (unsigned long)(*ppos / PAGE_SIZE);
  55         if (pfn > saved_max_pfn)
  56                 return -EINVAL;
  57
  58         do {
  59                 if (count > (PAGE_SIZE - offset))
  60                         nr_bytes = PAGE_SIZE - offset;
  61                 else
  62                         nr_bytes = count;
  63
  64                 tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf);
  65                 if (tmp < 0)
  66                         return tmp;
  67                 *ppos += nr_bytes;
  68                 count -= nr_bytes;
  69                 buf += nr_bytes;
  70                 read += nr_bytes;
  71                 ++pfn;
  72                 offset = 0;
  73         } while (count);
  74
  75         return read;
  76 }
  77
  78 /* Maps vmcore file offset to respective physical address in memroy. */
  79 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
  80                                         struct vmcore **m_ptr)
  81 {
  82         struct vmcore *m;
  83         u64 paddr;
  84
  85         list_for_each_entry(m, vc_list, list) {
  86                 u64 start, end;
  87                 start = m->offset;
  88                 end = m->offset + m->size - 1;
  89                 if (offset >= start && offset <= end) {
  90                         paddr = m->paddr + offset - start;
  91                         *m_ptr = m;
  92                         return paddr;
  93                 }
  94         }
  95         *m_ptr = NULL;
  96         return 0;
  97 }
  98
  99 /* Read from the ELF header and then the crash dump. On error, negative value is
 100  * returned otherwise number of bytes read are returned.
 101  */
 102 static ssize_t read_vmcore(struct file *file, char __user *buffer,
 103                                 size_t buflen, loff_t *fpos)
 104 {
 105         ssize_t acc = 0, tmp;
 106         size_t tsz;
 107         u64 start, nr_bytes;
 108         struct vmcore *curr_m = NULL;
 109
 110         if (buflen == 0 || *fpos >= vmcore_size)
 111                 return 0;
 112
 113         /* trim buflen to not go beyond EOF */
 114         if (buflen > vmcore_size - *fpos)
 115                 buflen = vmcore_size - *fpos;
 116
 117         /* Read ELF core header */
 118         if (*fpos < elfcorebuf_sz) {
 119                 tsz = elfcorebuf_sz - *fpos;
 120                 if (buflen < tsz)
 121                         tsz = buflen;
 122                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
 123                         return -EFAULT;
 124                 buflen -= tsz;
 125                 *fpos += tsz;
 126                 buffer += tsz;
 127                 acc += tsz;
 128
 129                 /* leave now if filled buffer already */
 130                 if (buflen == 0)
 131                         return acc;
 132         }
 133
 134         start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
 135         if (!curr_m)
 136                 return -EINVAL;
 137         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 138                 tsz = buflen;
 139
 140         /* Calculate left bytes in current memory segment. */
 141         nr_bytes = (curr_m->size - (start - curr_m->paddr));
 142         if (tsz > nr_bytes)
 143                 tsz = nr_bytes;
 144
 145         while (buflen) {
 146                 tmp = read_from_oldmem(buffer, tsz, &start, 1);
 147                 if (tmp < 0)
 148                         return tmp;
 149                 buflen -= tsz;
 150                 *fpos += tsz;
 151                 buffer += tsz;
 152                 acc += tsz;
 153                 if (start >= (curr_m->paddr + curr_m->size)) {
 154                         if (curr_m->list.next == &vmcore_list)
 155                                 return acc;     /*EOF*/
 156                         curr_m = list_entry(curr_m->list.next,
 157                                                 struct vmcore, list);
 158                         start = curr_m->paddr;
 159                 }
 160                 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 161                         tsz = buflen;
 162                 /* Calculate left bytes in current memory segment. */
 163                 nr_bytes = (curr_m->size - (start - curr_m->paddr));
 164                 if (tsz > nr_bytes)
 165                         tsz = nr_bytes;
 166         }
 167         return acc;
 168 }
 169
 170 static int open_vmcore(struct inode *inode, struct file *filp)
 171 {
 172         return 0;
 173 }
 174
 175 const struct file_operations proc_vmcore_operations = {
 176         .read           = read_vmcore,
 177         .open           = open_vmcore,
 178 };
 179
 180 static struct vmcore* __init get_new_element(void)
 181 {
 182         struct vmcore *p;
 183
 184         p = kmalloc(sizeof(*p), GFP_KERNEL);
 185         if (p)
 186                 memset(p, 0, sizeof(*p));
 187         return p;
 188 }
 189
 190 static u64 __init get_vmcore_size_elf64(char *elfptr)
 191 {
 192         int i;
 193         u64 size;
 194         Elf64_Ehdr *ehdr_ptr;
 195         Elf64_Phdr *phdr_ptr;
 196
 197         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 198         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 199         size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
 200         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 201                 size += phdr_ptr->p_memsz;
 202                 phdr_ptr++;
 203         }
 204         return size;
 205 }
 206
 207 static u64 __init get_vmcore_size_elf32(char *elfptr)
 208 {
 209         int i;
 210         u64 size;
 211         Elf32_Ehdr *ehdr_ptr;
 212         Elf32_Phdr *phdr_ptr;
 213
 214         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 215         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 216         size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
 217         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 218                 size += phdr_ptr->p_memsz;
 219                 phdr_ptr++;
 220         }
 221         return size;
 222 }
 223
 224 /* Merges all the PT_NOTE headers into one. */
 225 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 226                                                 struct list_head *vc_list)
 227 {
 228         int i, nr_ptnote=0, rc=0;
 229         char *tmp;
 230         Elf64_Ehdr *ehdr_ptr;
 231         Elf64_Phdr phdr, *phdr_ptr;
 232         Elf64_Nhdr *nhdr_ptr;
 233         u64 phdr_sz = 0, note_off;
 234
 235         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 236         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 237         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 238                 int j;
 239                 void *notes_section;
 240                 struct vmcore *new;
 241                 u64 offset, max_sz, sz, real_sz = 0;
 242                 if (phdr_ptr->p_type != PT_NOTE)
 243                         continue;
 244                 nr_ptnote++;
 245                 max_sz = phdr_ptr->p_memsz;
 246                 offset = phdr_ptr->p_offset;
 247                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 248                 if (!notes_section)
 249                         return -ENOMEM;
 250                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 251                 if (rc < 0) {
 252                         kfree(notes_section);
 253                         return rc;
 254                 }
 255                 nhdr_ptr = notes_section;
 256                 for (j = 0; j < max_sz; j += sz) {
 257                         if (nhdr_ptr->n_namesz == 0)
 258                                 break;
 259                         sz = sizeof(Elf64_Nhdr) +
 260                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 261                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 262                         real_sz += sz;
 263                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 264                 }
 265
 266                 /* Add this contiguous chunk of notes section to vmcore list.*/
 267                 new = get_new_element();
 268                 if (!new) {
 269                         kfree(notes_section);
 270                         return -ENOMEM;
 271                 }
 272                 new->paddr = phdr_ptr->p_offset;
 273                 new->size = real_sz;
 274                 list_add_tail(&new->list, vc_list);
 275                 phdr_sz += real_sz;
 276                 kfree(notes_section);
 277         }
 278
 279         /* Prepare merged PT_NOTE program header. */
 280         phdr.p_type    = PT_NOTE;
 281         phdr.p_flags   = 0;
 282         note_off = sizeof(Elf64_Ehdr) +
 283                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 284         phdr.p_offset  = note_off;
 285         phdr.p_vaddr   = phdr.p_paddr = 0;
 286         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 287         phdr.p_align   = 0;
 288
 289         /* Add merged PT_NOTE program header*/
 290         tmp = elfptr + sizeof(Elf64_Ehdr);
 291         memcpy(tmp, &phdr, sizeof(phdr));
 292         tmp += sizeof(phdr);
 293
 294         /* Remove unwanted PT_NOTE program headers. */
 295         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 296         *elfsz = *elfsz - i;
 297         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 298
 299         /* Modify e_phnum to reflect merged headers. */
 300         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 301
 302         return 0;
 303 }
 304
 305 /* Merges all the PT_NOTE headers into one. */
 306 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 307                                                 struct list_head *vc_list)
 308 {
 309         int i, nr_ptnote=0, rc=0;
 310         char *tmp;
 311         Elf32_Ehdr *ehdr_ptr;
 312         Elf32_Phdr phdr, *phdr_ptr;
 313         Elf32_Nhdr *nhdr_ptr;
 314         u64 phdr_sz = 0, note_off;
 315
 316         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 317         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 318         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 319                 int j;
 320                 void *notes_section;
 321                 struct vmcore *new;
 322                 u64 offset, max_sz, sz, real_sz = 0;
 323                 if (phdr_ptr->p_type != PT_NOTE)
 324                         continue;
 325                 nr_ptnote++;
 326                 max_sz = phdr_ptr->p_memsz;
 327                 offset = phdr_ptr->p_offset;
 328                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 329                 if (!notes_section)
 330                         return -ENOMEM;
 331                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 332                 if (rc < 0) {
 333                         kfree(notes_section);
 334                         return rc;
 335                 }
 336                 nhdr_ptr = notes_section;
 337                 for (j = 0; j < max_sz; j += sz) {
 338                         if (nhdr_ptr->n_namesz == 0)
 339                                 break;
 340                         sz = sizeof(Elf32_Nhdr) +
 341                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 342                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 343                         real_sz += sz;
 344                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 345                 }
 346
 347                 /* Add this contiguous chunk of notes section to vmcore list.*/
 348                 new = get_new_element();
 349                 if (!new) {
 350                         kfree(notes_section);
 351                         return -ENOMEM;
 352                 }
 353                 new->paddr = phdr_ptr->p_offset;
 354                 new->size = real_sz;
 355                 list_add_tail(&new->list, vc_list);
 356                 phdr_sz += real_sz;
 357                 kfree(notes_section);
 358         }
 359
 360         /* Prepare merged PT_NOTE program header. */
 361         phdr.p_type    = PT_NOTE;
 362         phdr.p_flags   = 0;
 363         note_off = sizeof(Elf32_Ehdr) +
 364                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
 365         phdr.p_offset  = note_off;
 366         phdr.p_vaddr   = phdr.p_paddr = 0;
 367         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 368         phdr.p_align   = 0;
 369
 370         /* Add merged PT_NOTE program header*/
 371         tmp = elfptr + sizeof(Elf32_Ehdr);
 372         memcpy(tmp, &phdr, sizeof(phdr));
 373         tmp += sizeof(phdr);
 374
 375         /* Remove unwanted PT_NOTE program headers. */
 376         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
 377         *elfsz = *elfsz - i;
 378         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
 379
 380         /* Modify e_phnum to reflect merged headers. */
 381         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 382
 383         return 0;
 384 }
 385
 386 /* Add memory chunks represented by program headers to vmcore list. Also update
 387  * the new offset fields of exported program headers. */
 388 static int __init process_ptload_program_headers_elf64(char *elfptr,
 389                                                 size_t elfsz,
 390                                                 struct list_head *vc_list)
 391 {
 392         int i;
 393         Elf64_Ehdr *ehdr_ptr;
 394         Elf64_Phdr *phdr_ptr;
 395         loff_t vmcore_off;
 396         struct vmcore *new;
 397
 398         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 399         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 400
 401         /* First program header is PT_NOTE header. */
 402         vmcore_off = sizeof(Elf64_Ehdr) +
 403                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
 404                         phdr_ptr->p_memsz; /* Note sections */
 405
 406         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 407                 if (phdr_ptr->p_type != PT_LOAD)
 408                         continue;
 409
 410                 /* Add this contiguous chunk of memory to vmcore list.*/
 411                 new = get_new_element();
 412                 if (!new)
 413                         return -ENOMEM;
 414                 new->paddr = phdr_ptr->p_offset;
 415                 new->size = phdr_ptr->p_memsz;
 416                 list_add_tail(&new->list, vc_list);
 417
 418                 /* Update the program header offset. */
 419                 phdr_ptr->p_offset = vmcore_off;
 420                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 421         }
 422         return 0;
 423 }
 424
 425 static int __init process_ptload_program_headers_elf32(char *elfptr,
 426                                                 size_t elfsz,
 427                                                 struct list_head *vc_list)
 428 {
 429         int i;
 430         Elf32_Ehdr *ehdr_ptr;
 431         Elf32_Phdr *phdr_ptr;
 432         loff_t vmcore_off;
 433         struct vmcore *new;
 434
 435         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 436         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
 437
 438         /* First program header is PT_NOTE header. */
 439         vmcore_off = sizeof(Elf32_Ehdr) +
 440                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
 441                         phdr_ptr->p_memsz; /* Note sections */
 442
 443         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 444                 if (phdr_ptr->p_type != PT_LOAD)
 445                         continue;
 446
 447                 /* Add this contiguous chunk of memory to vmcore list.*/
 448                 new = get_new_element();
 449                 if (!new)
 450                         return -ENOMEM;
 451                 new->paddr = phdr_ptr->p_offset;
 452                 new->size = phdr_ptr->p_memsz;
 453                 list_add_tail(&new->list, vc_list);
 454
 455                 /* Update the program header offset */
 456                 phdr_ptr->p_offset = vmcore_off;
 457                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 458         }
 459         return 0;
 460 }
 461
 462 /* Sets offset fields of vmcore elements. */
 463 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
 464                                                 struct list_head *vc_list)
 465 {
 466         loff_t vmcore_off;
 467         Elf64_Ehdr *ehdr_ptr;
 468         struct vmcore *m;
 469
 470         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 471
 472         /* Skip Elf header and program headers. */
 473         vmcore_off = sizeof(Elf64_Ehdr) +
 474                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
 475
 476         list_for_each_entry(m, vc_list, list) {
 477                 m->offset = vmcore_off;
 478                 vmcore_off += m->size;
 479         }
 480 }
 481
 482 /* Sets offset fields of vmcore elements. */
 483 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
 484                                                 struct list_head *vc_list)
 485 {
 486         loff_t vmcore_off;
 487         Elf32_Ehdr *ehdr_ptr;
 488         struct vmcore *m;
 489
 490         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 491
 492         /* Skip Elf header and program headers. */
 493         vmcore_off = sizeof(Elf32_Ehdr) +
 494                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
 495
 496         list_for_each_entry(m, vc_list, list) {
 497                 m->offset = vmcore_off;
 498                 vmcore_off += m->size;
 499         }
 500 }
 501
 502 static int __init parse_crash_elf64_headers(void)
 503 {
 504         int rc=0;
 505         Elf64_Ehdr ehdr;
 506         u64 addr;
 507
 508         addr = elfcorehdr_addr;
 509
 510         /* Read Elf header */
 511         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
 512         if (rc < 0)
 513                 return rc;
 514
 515         /* Do some basic Verification. */
 516         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 517                 (ehdr.e_type != ET_CORE) ||
 518                 !elf_check_arch(&ehdr) ||
 519                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
 520                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 521                 ehdr.e_version != EV_CURRENT ||
 522                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
 523                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
 524                 ehdr.e_phnum == 0) {
 525                 printk(KERN_WARNING "Warning: Core image elf header is not"
 526                                         "sane\n");
 527                 return -EINVAL;
 528         }
 529
 530         /* Read in all elf headers. */
 531         elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
 532         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 533         if (!elfcorebuf)
 534                 return -ENOMEM;
 535         addr = elfcorehdr_addr;
 536         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 537         if (rc < 0) {
 538                 kfree(elfcorebuf);
 539                 return rc;
 540         }
 541
 542         /* Merge all PT_NOTE headers into one. */
 543         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 544         if (rc) {
 545                 kfree(elfcorebuf);
 546                 return rc;
 547         }
 548         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
 549                                                         &vmcore_list);
 550         if (rc) {
 551                 kfree(elfcorebuf);
 552                 return rc;
 553         }
 554         set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
 555         return 0;
 556 }
 557
 558 static int __init parse_crash_elf32_headers(void)
 559 {
 560         int rc=0;
 561         Elf32_Ehdr ehdr;
 562         u64 addr;
 563
 564         addr = elfcorehdr_addr;
 565
 566         /* Read Elf header */
 567         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
 568         if (rc < 0)
 569                 return rc;
 570
 571         /* Do some basic Verification. */
 572         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 573                 (ehdr.e_type != ET_CORE) ||
 574                 !elf_check_arch(&ehdr) ||
 575                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
 576                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 577                 ehdr.e_version != EV_CURRENT ||
 578                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
 579                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
 580                 ehdr.e_phnum == 0) {
 581                 printk(KERN_WARNING "Warning: Core image elf header is not"
 582                                         "sane\n");
 583                 return -EINVAL;
 584         }
 585
 586         /* Read in all elf headers. */
 587         elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
 588         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 589         if (!elfcorebuf)
 590                 return -ENOMEM;
 591         addr = elfcorehdr_addr;
 592         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 593         if (rc < 0) {
 594                 kfree(elfcorebuf);
 595                 return rc;
 596         }
 597
 598         /* Merge all PT_NOTE headers into one. */
 599         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 600         if (rc) {
 601                 kfree(elfcorebuf);
 602                 return rc;
 603         }
 604         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
 605                                                                 &vmcore_list);
 606         if (rc) {
 607                 kfree(elfcorebuf);
 608                 return rc;
 609         }
 610         set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
 611         return 0;
 612 }
 613
 614 static int __init parse_crash_elf_headers(void)
 615 {
 616         unsigned char e_ident[EI_NIDENT];
 617         u64 addr;
 618         int rc=0;
 619
 620         addr = elfcorehdr_addr;
 621         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
 622         if (rc < 0)
 623                 return rc;
 624         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
 625                 printk(KERN_WARNING "Warning: Core image elf header"
 626                                         " not found\n");
 627                 return -EINVAL;
 628         }
 629
 630         if (e_ident[EI_CLASS] == ELFCLASS64) {
 631                 rc = parse_crash_elf64_headers();
 632                 if (rc)
 633                         return rc;
 634
 635                 /* Determine vmcore size. */
 636                 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
 637         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
 638                 rc = parse_crash_elf32_headers();
 639                 if (rc)
 640                         return rc;
 641
 642                 /* Determine vmcore size. */
 643                 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
 644         } else {
 645                 printk(KERN_WARNING "Warning: Core image elf header is not"
 646                                         " sane\n");
 647                 return -EINVAL;
 648         }
 649         return 0;
 650 }
 651
 652 /* Init function for vmcore module. */
 653 static int __init vmcore_init(void)
 654 {
 655         int rc = 0;
 656
 657         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
 658         if (!(elfcorehdr_addr < ELFCORE_ADDR_MAX))
 659                 return rc;
 660         rc = parse_crash_elf_headers();
 661         if (rc) {
 662                 printk(KERN_WARNING "Kdump: vmcore not initialized\n");
 663                 return rc;
 664         }
 665
 666         /* Initialize /proc/vmcore size if proc is already up. */
 667         if (proc_vmcore)
 668                 proc_vmcore->size = vmcore_size;
 669         return 0;
 670 }
 671 module_init(vmcore_init)