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/export.h>
  16 #include <linux/slab.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 static struct proc_dir_entry *proc_vmcore = NULL;
  38
  39 /*
  40  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  41  * The called function has to take care of module refcounting.
  42  */
  43 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
  44
  45 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
  46 {
  47         if (oldmem_pfn_is_ram)
  48                 return -EBUSY;
  49         oldmem_pfn_is_ram = fn;
  50         return 0;
  51 }
  52 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
  53
  54 void unregister_oldmem_pfn_is_ram(void)
  55 {
  56         oldmem_pfn_is_ram = NULL;
  57         wmb();
  58 }
  59 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
  60
  61 static int pfn_is_ram(unsigned long pfn)
  62 {
  63         int (*fn)(unsigned long pfn);
  64         /* pfn is ram unless fn() checks pagetype */
  65         int ret = 1;
  66
  67         /*
  68          * Ask hypervisor if the pfn is really ram.
  69          * A ballooned page contains no data and reading from such a page
  70          * will cause high load in the hypervisor.
  71          */
  72         fn = oldmem_pfn_is_ram;
  73         if (fn)
  74                 ret = fn(pfn);
  75
  76         return ret;
  77 }
  78
  79 /* Reads a page from the oldmem device from given offset. */
  80 static ssize_t read_from_oldmem(char *buf, size_t count,
  81                                 u64 *ppos, int userbuf)
  82 {
  83         unsigned long pfn, offset;
  84         size_t nr_bytes;
  85         ssize_t read = 0, tmp;
  86
  87         if (!count)
  88                 return 0;
  89
  90         offset = (unsigned long)(*ppos % PAGE_SIZE);
  91         pfn = (unsigned long)(*ppos / PAGE_SIZE);
  92
  93         do {
  94                 if (count > (PAGE_SIZE - offset))
  95                         nr_bytes = PAGE_SIZE - offset;
  96                 else
  97                         nr_bytes = count;
  98
  99                 /* If pfn is not ram, return zeros for sparse dump files */
 100                 if (pfn_is_ram(pfn) == 0)
 101                         memset(buf, 0, nr_bytes);
 102                 else {
 103                         tmp = copy_oldmem_page(pfn, buf, nr_bytes,
 104                                                 offset, userbuf);
 105                         if (tmp < 0)
 106                                 return tmp;
 107                 }
 108                 *ppos += nr_bytes;
 109                 count -= nr_bytes;
 110                 buf += nr_bytes;
 111                 read += nr_bytes;
 112                 ++pfn;
 113                 offset = 0;
 114         } while (count);
 115
 116         return read;
 117 }
 118
 119 /* Maps vmcore file offset to respective physical address in memroy. */
 120 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
 121                                         struct vmcore **m_ptr)
 122 {
 123         struct vmcore *m;
 124         u64 paddr;
 125
 126         list_for_each_entry(m, vc_list, list) {
 127                 u64 start, end;
 128                 start = m->offset;
 129                 end = m->offset + m->size - 1;
 130                 if (offset >= start && offset <= end) {
 131                         paddr = m->paddr + offset - start;
 132                         *m_ptr = m;
 133                         return paddr;
 134                 }
 135         }
 136         *m_ptr = NULL;
 137         return 0;
 138 }
 139
 140 /* Read from the ELF header and then the crash dump. On error, negative value is
 141  * returned otherwise number of bytes read are returned.
 142  */
 143 static ssize_t read_vmcore(struct file *file, char __user *buffer,
 144                                 size_t buflen, loff_t *fpos)
 145 {
 146         ssize_t acc = 0, tmp;
 147         size_t tsz;
 148         u64 start, nr_bytes;
 149         struct vmcore *curr_m = NULL;
 150
 151         if (buflen == 0 || *fpos >= vmcore_size)
 152                 return 0;
 153
 154         /* trim buflen to not go beyond EOF */
 155         if (buflen > vmcore_size - *fpos)
 156                 buflen = vmcore_size - *fpos;
 157
 158         /* Read ELF core header */
 159         if (*fpos < elfcorebuf_sz) {
 160                 tsz = elfcorebuf_sz - *fpos;
 161                 if (buflen < tsz)
 162                         tsz = buflen;
 163                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
 164                         return -EFAULT;
 165                 buflen -= tsz;
 166                 *fpos += tsz;
 167                 buffer += tsz;
 168                 acc += tsz;
 169
 170                 /* leave now if filled buffer already */
 171                 if (buflen == 0)
 172                         return acc;
 173         }
 174
 175         start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
 176         if (!curr_m)
 177                 return -EINVAL;
 178         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 179                 tsz = buflen;
 180
 181         /* Calculate left bytes in current memory segment. */
 182         nr_bytes = (curr_m->size - (start - curr_m->paddr));
 183         if (tsz > nr_bytes)
 184                 tsz = nr_bytes;
 185
 186         while (buflen) {
 187                 tmp = read_from_oldmem(buffer, tsz, &start, 1);
 188                 if (tmp < 0)
 189                         return tmp;
 190                 buflen -= tsz;
 191                 *fpos += tsz;
 192                 buffer += tsz;
 193                 acc += tsz;
 194                 if (start >= (curr_m->paddr + curr_m->size)) {
 195                         if (curr_m->list.next == &vmcore_list)
 196                                 return acc;     /*EOF*/
 197                         curr_m = list_entry(curr_m->list.next,
 198                                                 struct vmcore, list);
 199                         start = curr_m->paddr;
 200                 }
 201                 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 202                         tsz = buflen;
 203                 /* Calculate left bytes in current memory segment. */
 204                 nr_bytes = (curr_m->size - (start - curr_m->paddr));
 205                 if (tsz > nr_bytes)
 206                         tsz = nr_bytes;
 207         }
 208         return acc;
 209 }
 210
 211 static const struct file_operations proc_vmcore_operations = {
 212         .read           = read_vmcore,
 213         .llseek         = default_llseek,
 214 };
 215
 216 static struct vmcore* __init get_new_element(void)
 217 {
 218         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
 219 }
 220
 221 static u64 __init get_vmcore_size_elf64(char *elfptr)
 222 {
 223         int i;
 224         u64 size;
 225         Elf64_Ehdr *ehdr_ptr;
 226         Elf64_Phdr *phdr_ptr;
 227
 228         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 229         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 230         size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
 231         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 232                 size += phdr_ptr->p_memsz;
 233                 phdr_ptr++;
 234         }
 235         return size;
 236 }
 237
 238 static u64 __init get_vmcore_size_elf32(char *elfptr)
 239 {
 240         int i;
 241         u64 size;
 242         Elf32_Ehdr *ehdr_ptr;
 243         Elf32_Phdr *phdr_ptr;
 244
 245         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 246         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 247         size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
 248         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 249                 size += phdr_ptr->p_memsz;
 250                 phdr_ptr++;
 251         }
 252         return size;
 253 }
 254
 255 /* Merges all the PT_NOTE headers into one. */
 256 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 257                                                 struct list_head *vc_list)
 258 {
 259         int i, nr_ptnote=0, rc=0;
 260         char *tmp;
 261         Elf64_Ehdr *ehdr_ptr;
 262         Elf64_Phdr phdr, *phdr_ptr;
 263         Elf64_Nhdr *nhdr_ptr;
 264         u64 phdr_sz = 0, note_off;
 265
 266         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 267         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 268         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 269                 int j;
 270                 void *notes_section;
 271                 struct vmcore *new;
 272                 u64 offset, max_sz, sz, real_sz = 0;
 273                 if (phdr_ptr->p_type != PT_NOTE)
 274                         continue;
 275                 nr_ptnote++;
 276                 max_sz = phdr_ptr->p_memsz;
 277                 offset = phdr_ptr->p_offset;
 278                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 279                 if (!notes_section)
 280                         return -ENOMEM;
 281                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 282                 if (rc < 0) {
 283                         kfree(notes_section);
 284                         return rc;
 285                 }
 286                 nhdr_ptr = notes_section;
 287                 for (j = 0; j < max_sz; j += sz) {
 288                         if (nhdr_ptr->n_namesz == 0)
 289                                 break;
 290                         sz = sizeof(Elf64_Nhdr) +
 291                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 292                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 293                         real_sz += sz;
 294                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 295                 }
 296
 297                 /* Add this contiguous chunk of notes section to vmcore list.*/
 298                 new = get_new_element();
 299                 if (!new) {
 300                         kfree(notes_section);
 301                         return -ENOMEM;
 302                 }
 303                 new->paddr = phdr_ptr->p_offset;
 304                 new->size = real_sz;
 305                 list_add_tail(&new->list, vc_list);
 306                 phdr_sz += real_sz;
 307                 kfree(notes_section);
 308         }
 309
 310         /* Prepare merged PT_NOTE program header. */
 311         phdr.p_type    = PT_NOTE;
 312         phdr.p_flags   = 0;
 313         note_off = sizeof(Elf64_Ehdr) +
 314                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 315         phdr.p_offset  = note_off;
 316         phdr.p_vaddr   = phdr.p_paddr = 0;
 317         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 318         phdr.p_align   = 0;
 319
 320         /* Add merged PT_NOTE program header*/
 321         tmp = elfptr + sizeof(Elf64_Ehdr);
 322         memcpy(tmp, &phdr, sizeof(phdr));
 323         tmp += sizeof(phdr);
 324
 325         /* Remove unwanted PT_NOTE program headers. */
 326         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 327         *elfsz = *elfsz - i;
 328         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 329
 330         /* Modify e_phnum to reflect merged headers. */
 331         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 332
 333         return 0;
 334 }
 335
 336 /* Merges all the PT_NOTE headers into one. */
 337 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 338                                                 struct list_head *vc_list)
 339 {
 340         int i, nr_ptnote=0, rc=0;
 341         char *tmp;
 342         Elf32_Ehdr *ehdr_ptr;
 343         Elf32_Phdr phdr, *phdr_ptr;
 344         Elf32_Nhdr *nhdr_ptr;
 345         u64 phdr_sz = 0, note_off;
 346
 347         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 348         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 349         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 350                 int j;
 351                 void *notes_section;
 352                 struct vmcore *new;
 353                 u64 offset, max_sz, sz, real_sz = 0;
 354                 if (phdr_ptr->p_type != PT_NOTE)
 355                         continue;
 356                 nr_ptnote++;
 357                 max_sz = phdr_ptr->p_memsz;
 358                 offset = phdr_ptr->p_offset;
 359                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 360                 if (!notes_section)
 361                         return -ENOMEM;
 362                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 363                 if (rc < 0) {
 364                         kfree(notes_section);
 365                         return rc;
 366                 }
 367                 nhdr_ptr = notes_section;
 368                 for (j = 0; j < max_sz; j += sz) {
 369                         if (nhdr_ptr->n_namesz == 0)
 370                                 break;
 371                         sz = sizeof(Elf32_Nhdr) +
 372                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 373                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 374                         real_sz += sz;
 375                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 376                 }
 377
 378                 /* Add this contiguous chunk of notes section to vmcore list.*/
 379                 new = get_new_element();
 380                 if (!new) {
 381                         kfree(notes_section);
 382                         return -ENOMEM;
 383                 }
 384                 new->paddr = phdr_ptr->p_offset;
 385                 new->size = real_sz;
 386                 list_add_tail(&new->list, vc_list);
 387                 phdr_sz += real_sz;
 388                 kfree(notes_section);
 389         }
 390
 391         /* Prepare merged PT_NOTE program header. */
 392         phdr.p_type    = PT_NOTE;
 393         phdr.p_flags   = 0;
 394         note_off = sizeof(Elf32_Ehdr) +
 395                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
 396         phdr.p_offset  = note_off;
 397         phdr.p_vaddr   = phdr.p_paddr = 0;
 398         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 399         phdr.p_align   = 0;
 400
 401         /* Add merged PT_NOTE program header*/
 402         tmp = elfptr + sizeof(Elf32_Ehdr);
 403         memcpy(tmp, &phdr, sizeof(phdr));
 404         tmp += sizeof(phdr);
 405
 406         /* Remove unwanted PT_NOTE program headers. */
 407         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
 408         *elfsz = *elfsz - i;
 409         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
 410
 411         /* Modify e_phnum to reflect merged headers. */
 412         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 413
 414         return 0;
 415 }
 416
 417 /* Add memory chunks represented by program headers to vmcore list. Also update
 418  * the new offset fields of exported program headers. */
 419 static int __init process_ptload_program_headers_elf64(char *elfptr,
 420                                                 size_t elfsz,
 421                                                 struct list_head *vc_list)
 422 {
 423         int i;
 424         Elf64_Ehdr *ehdr_ptr;
 425         Elf64_Phdr *phdr_ptr;
 426         loff_t vmcore_off;
 427         struct vmcore *new;
 428
 429         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 430         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 431
 432         /* First program header is PT_NOTE header. */
 433         vmcore_off = sizeof(Elf64_Ehdr) +
 434                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
 435                         phdr_ptr->p_memsz; /* Note sections */
 436
 437         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 438                 if (phdr_ptr->p_type != PT_LOAD)
 439                         continue;
 440
 441                 /* Add this contiguous chunk of memory to vmcore list.*/
 442                 new = get_new_element();
 443                 if (!new)
 444                         return -ENOMEM;
 445                 new->paddr = phdr_ptr->p_offset;
 446                 new->size = phdr_ptr->p_memsz;
 447                 list_add_tail(&new->list, vc_list);
 448
 449                 /* Update the program header offset. */
 450                 phdr_ptr->p_offset = vmcore_off;
 451                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 452         }
 453         return 0;
 454 }
 455
 456 static int __init process_ptload_program_headers_elf32(char *elfptr,
 457                                                 size_t elfsz,
 458                                                 struct list_head *vc_list)
 459 {
 460         int i;
 461         Elf32_Ehdr *ehdr_ptr;
 462         Elf32_Phdr *phdr_ptr;
 463         loff_t vmcore_off;
 464         struct vmcore *new;
 465
 466         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 467         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
 468
 469         /* First program header is PT_NOTE header. */
 470         vmcore_off = sizeof(Elf32_Ehdr) +
 471                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
 472                         phdr_ptr->p_memsz; /* Note sections */
 473
 474         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 475                 if (phdr_ptr->p_type != PT_LOAD)
 476                         continue;
 477
 478                 /* Add this contiguous chunk of memory to vmcore list.*/
 479                 new = get_new_element();
 480                 if (!new)
 481                         return -ENOMEM;
 482                 new->paddr = phdr_ptr->p_offset;
 483                 new->size = phdr_ptr->p_memsz;
 484                 list_add_tail(&new->list, vc_list);
 485
 486                 /* Update the program header offset */
 487                 phdr_ptr->p_offset = vmcore_off;
 488                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 489         }
 490         return 0;
 491 }
 492
 493 /* Sets offset fields of vmcore elements. */
 494 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
 495                                                 struct list_head *vc_list)
 496 {
 497         loff_t vmcore_off;
 498         Elf64_Ehdr *ehdr_ptr;
 499         struct vmcore *m;
 500
 501         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 502
 503         /* Skip Elf header and program headers. */
 504         vmcore_off = sizeof(Elf64_Ehdr) +
 505                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
 506
 507         list_for_each_entry(m, vc_list, list) {
 508                 m->offset = vmcore_off;
 509                 vmcore_off += m->size;
 510         }
 511 }
 512
 513 /* Sets offset fields of vmcore elements. */
 514 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
 515                                                 struct list_head *vc_list)
 516 {
 517         loff_t vmcore_off;
 518         Elf32_Ehdr *ehdr_ptr;
 519         struct vmcore *m;
 520
 521         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 522
 523         /* Skip Elf header and program headers. */
 524         vmcore_off = sizeof(Elf32_Ehdr) +
 525                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
 526
 527         list_for_each_entry(m, vc_list, list) {
 528                 m->offset = vmcore_off;
 529                 vmcore_off += m->size;
 530         }
 531 }
 532
 533 static int __init parse_crash_elf64_headers(void)
 534 {
 535         int rc=0;
 536         Elf64_Ehdr ehdr;
 537         u64 addr;
 538
 539         addr = elfcorehdr_addr;
 540
 541         /* Read Elf header */
 542         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
 543         if (rc < 0)
 544                 return rc;
 545
 546         /* Do some basic Verification. */
 547         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 548                 (ehdr.e_type != ET_CORE) ||
 549                 !vmcore_elf64_check_arch(&ehdr) ||
 550                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
 551                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 552                 ehdr.e_version != EV_CURRENT ||
 553                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
 554                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
 555                 ehdr.e_phnum == 0) {
 556                 printk(KERN_WARNING "Warning: Core image elf header is not"
 557                                         "sane\n");
 558                 return -EINVAL;
 559         }
 560
 561         /* Read in all elf headers. */
 562         elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
 563         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 564         if (!elfcorebuf)
 565                 return -ENOMEM;
 566         addr = elfcorehdr_addr;
 567         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 568         if (rc < 0) {
 569                 kfree(elfcorebuf);
 570                 return rc;
 571         }
 572
 573         /* Merge all PT_NOTE headers into one. */
 574         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 575         if (rc) {
 576                 kfree(elfcorebuf);
 577                 return rc;
 578         }
 579         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
 580                                                         &vmcore_list);
 581         if (rc) {
 582                 kfree(elfcorebuf);
 583                 return rc;
 584         }
 585         set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
 586         return 0;
 587 }
 588
 589 static int __init parse_crash_elf32_headers(void)
 590 {
 591         int rc=0;
 592         Elf32_Ehdr ehdr;
 593         u64 addr;
 594
 595         addr = elfcorehdr_addr;
 596
 597         /* Read Elf header */
 598         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
 599         if (rc < 0)
 600                 return rc;
 601
 602         /* Do some basic Verification. */
 603         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 604                 (ehdr.e_type != ET_CORE) ||
 605                 !elf_check_arch(&ehdr) ||
 606                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
 607                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 608                 ehdr.e_version != EV_CURRENT ||
 609                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
 610                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
 611                 ehdr.e_phnum == 0) {
 612                 printk(KERN_WARNING "Warning: Core image elf header is not"
 613                                         "sane\n");
 614                 return -EINVAL;
 615         }
 616
 617         /* Read in all elf headers. */
 618         elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
 619         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 620         if (!elfcorebuf)
 621                 return -ENOMEM;
 622         addr = elfcorehdr_addr;
 623         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 624         if (rc < 0) {
 625                 kfree(elfcorebuf);
 626                 return rc;
 627         }
 628
 629         /* Merge all PT_NOTE headers into one. */
 630         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 631         if (rc) {
 632                 kfree(elfcorebuf);
 633                 return rc;
 634         }
 635         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
 636                                                                 &vmcore_list);
 637         if (rc) {
 638                 kfree(elfcorebuf);
 639                 return rc;
 640         }
 641         set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
 642         return 0;
 643 }
 644
 645 static int __init parse_crash_elf_headers(void)
 646 {
 647         unsigned char e_ident[EI_NIDENT];
 648         u64 addr;
 649         int rc=0;
 650
 651         addr = elfcorehdr_addr;
 652         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
 653         if (rc < 0)
 654                 return rc;
 655         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
 656                 printk(KERN_WARNING "Warning: Core image elf header"
 657                                         " not found\n");
 658                 return -EINVAL;
 659         }
 660
 661         if (e_ident[EI_CLASS] == ELFCLASS64) {
 662                 rc = parse_crash_elf64_headers();
 663                 if (rc)
 664                         return rc;
 665
 666                 /* Determine vmcore size. */
 667                 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
 668         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
 669                 rc = parse_crash_elf32_headers();
 670                 if (rc)
 671                         return rc;
 672
 673                 /* Determine vmcore size. */
 674                 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
 675         } else {
 676                 printk(KERN_WARNING "Warning: Core image elf header is not"
 677                                         " sane\n");
 678                 return -EINVAL;
 679         }
 680         return 0;
 681 }
 682
 683 /* Init function for vmcore module. */
 684 static int __init vmcore_init(void)
 685 {
 686         int rc = 0;
 687
 688         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
 689         if (!(is_vmcore_usable()))
 690                 return rc;
 691         rc = parse_crash_elf_headers();
 692         if (rc) {
 693                 printk(KERN_WARNING "Kdump: vmcore not initialized\n");
 694                 return rc;
 695         }
 696
 697         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
 698         if (proc_vmcore)
 699                 proc_vmcore->size = vmcore_size;
 700         return 0;
 701 }
 702 module_init(vmcore_init)