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/kcore.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/printk.h>
  19 #include <linux/bootmem.h>
  20 #include <linux/init.h>
  21 #include <linux/crash_dump.h>
  22 #include <linux/list.h>
  23 #include <asm/uaccess.h>
  24 #include <asm/io.h>
  25 #include "internal.h"
  26
  27 /* List representing chunks of contiguous memory areas and their offsets in
  28  * vmcore file.
  29  */
  30 static LIST_HEAD(vmcore_list);
  31
  32 /* Stores the pointer to the buffer containing kernel elf core headers. */
  33 static char *elfcorebuf;
  34 static size_t elfcorebuf_sz;
  35 static size_t elfcorebuf_sz_orig;
  36
  37 /* Total size of vmcore file. */
  38 static u64 vmcore_size;
  39
  40 static struct proc_dir_entry *proc_vmcore = NULL;
  41
  42 /*
  43  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  44  * The called function has to take care of module refcounting.
  45  */
  46 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
  47
  48 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
  49 {
  50         if (oldmem_pfn_is_ram)
  51                 return -EBUSY;
  52         oldmem_pfn_is_ram = fn;
  53         return 0;
  54 }
  55 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
  56
  57 void unregister_oldmem_pfn_is_ram(void)
  58 {
  59         oldmem_pfn_is_ram = NULL;
  60         wmb();
  61 }
  62 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
  63
  64 static int pfn_is_ram(unsigned long pfn)
  65 {
  66         int (*fn)(unsigned long pfn);
  67         /* pfn is ram unless fn() checks pagetype */
  68         int ret = 1;
  69
  70         /*
  71          * Ask hypervisor if the pfn is really ram.
  72          * A ballooned page contains no data and reading from such a page
  73          * will cause high load in the hypervisor.
  74          */
  75         fn = oldmem_pfn_is_ram;
  76         if (fn)
  77                 ret = fn(pfn);
  78
  79         return ret;
  80 }
  81
  82 /* Reads a page from the oldmem device from given offset. */
  83 static ssize_t read_from_oldmem(char *buf, size_t count,
  84                                 u64 *ppos, int userbuf)
  85 {
  86         unsigned long pfn, offset;
  87         size_t nr_bytes;
  88         ssize_t read = 0, tmp;
  89
  90         if (!count)
  91                 return 0;
  92
  93         offset = (unsigned long)(*ppos % PAGE_SIZE);
  94         pfn = (unsigned long)(*ppos / PAGE_SIZE);
  95
  96         do {
  97                 if (count > (PAGE_SIZE - offset))
  98                         nr_bytes = PAGE_SIZE - offset;
  99                 else
 100                         nr_bytes = count;
 101
 102                 /* If pfn is not ram, return zeros for sparse dump files */
 103                 if (pfn_is_ram(pfn) == 0)
 104                         memset(buf, 0, nr_bytes);
 105                 else {
 106                         tmp = copy_oldmem_page(pfn, buf, nr_bytes,
 107                                                 offset, userbuf);
 108                         if (tmp < 0)
 109                                 return tmp;
 110                 }
 111                 *ppos += nr_bytes;
 112                 count -= nr_bytes;
 113                 buf += nr_bytes;
 114                 read += nr_bytes;
 115                 ++pfn;
 116                 offset = 0;
 117         } while (count);
 118
 119         return read;
 120 }
 121
 122 /* Read from the ELF header and then the crash dump. On error, negative value is
 123  * returned otherwise number of bytes read are returned.
 124  */
 125 static ssize_t read_vmcore(struct file *file, char __user *buffer,
 126                                 size_t buflen, loff_t *fpos)
 127 {
 128         ssize_t acc = 0, tmp;
 129         size_t tsz;
 130         u64 start;
 131         struct vmcore *m = NULL;
 132
 133         if (buflen == 0 || *fpos >= vmcore_size)
 134                 return 0;
 135
 136         /* trim buflen to not go beyond EOF */
 137         if (buflen > vmcore_size - *fpos)
 138                 buflen = vmcore_size - *fpos;
 139
 140         /* Read ELF core header */
 141         if (*fpos < elfcorebuf_sz) {
 142                 tsz = elfcorebuf_sz - *fpos;
 143                 if (buflen < tsz)
 144                         tsz = buflen;
 145                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
 146                         return -EFAULT;
 147                 buflen -= tsz;
 148                 *fpos += tsz;
 149                 buffer += tsz;
 150                 acc += tsz;
 151
 152                 /* leave now if filled buffer already */
 153                 if (buflen == 0)
 154                         return acc;
 155         }
 156
 157         list_for_each_entry(m, &vmcore_list, list) {
 158                 if (*fpos < m->offset + m->size) {
 159                         tsz = m->offset + m->size - *fpos;
 160                         if (buflen < tsz)
 161                                 tsz = buflen;
 162                         start = m->paddr + *fpos - m->offset;
 163                         tmp = read_from_oldmem(buffer, tsz, &start, 1);
 164                         if (tmp < 0)
 165                                 return tmp;
 166                         buflen -= tsz;
 167                         *fpos += tsz;
 168                         buffer += tsz;
 169                         acc += tsz;
 170
 171                         /* leave now if filled buffer already */
 172                         if (buflen == 0)
 173                                 return acc;
 174                 }
 175         }
 176
 177         return acc;
 178 }
 179
 180 static const struct file_operations proc_vmcore_operations = {
 181         .read           = read_vmcore,
 182         .llseek         = default_llseek,
 183 };
 184
 185 static struct vmcore* __init get_new_element(void)
 186 {
 187         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
 188 }
 189
 190 static u64 __init get_vmcore_size_elf64(char *elfptr, size_t elfsz)
 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 = elfsz;
 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, size_t elfsz)
 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 = elfsz;
 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         memset(elfptr + *elfsz, 0, i);
 299         *elfsz = roundup(*elfsz, PAGE_SIZE);
 300
 301         /* Modify e_phnum to reflect merged headers. */
 302         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 303
 304         return 0;
 305 }
 306
 307 /* Merges all the PT_NOTE headers into one. */
 308 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 309                                                 struct list_head *vc_list)
 310 {
 311         int i, nr_ptnote=0, rc=0;
 312         char *tmp;
 313         Elf32_Ehdr *ehdr_ptr;
 314         Elf32_Phdr phdr, *phdr_ptr;
 315         Elf32_Nhdr *nhdr_ptr;
 316         u64 phdr_sz = 0, note_off;
 317
 318         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 319         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 320         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 321                 int j;
 322                 void *notes_section;
 323                 struct vmcore *new;
 324                 u64 offset, max_sz, sz, real_sz = 0;
 325                 if (phdr_ptr->p_type != PT_NOTE)
 326                         continue;
 327                 nr_ptnote++;
 328                 max_sz = phdr_ptr->p_memsz;
 329                 offset = phdr_ptr->p_offset;
 330                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 331                 if (!notes_section)
 332                         return -ENOMEM;
 333                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 334                 if (rc < 0) {
 335                         kfree(notes_section);
 336                         return rc;
 337                 }
 338                 nhdr_ptr = notes_section;
 339                 for (j = 0; j < max_sz; j += sz) {
 340                         if (nhdr_ptr->n_namesz == 0)
 341                                 break;
 342                         sz = sizeof(Elf32_Nhdr) +
 343                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 344                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 345                         real_sz += sz;
 346                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 347                 }
 348
 349                 /* Add this contiguous chunk of notes section to vmcore list.*/
 350                 new = get_new_element();
 351                 if (!new) {
 352                         kfree(notes_section);
 353                         return -ENOMEM;
 354                 }
 355                 new->paddr = phdr_ptr->p_offset;
 356                 new->size = real_sz;
 357                 list_add_tail(&new->list, vc_list);
 358                 phdr_sz += real_sz;
 359                 kfree(notes_section);
 360         }
 361
 362         /* Prepare merged PT_NOTE program header. */
 363         phdr.p_type    = PT_NOTE;
 364         phdr.p_flags   = 0;
 365         note_off = sizeof(Elf32_Ehdr) +
 366                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
 367         phdr.p_offset  = note_off;
 368         phdr.p_vaddr   = phdr.p_paddr = 0;
 369         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 370         phdr.p_align   = 0;
 371
 372         /* Add merged PT_NOTE program header*/
 373         tmp = elfptr + sizeof(Elf32_Ehdr);
 374         memcpy(tmp, &phdr, sizeof(phdr));
 375         tmp += sizeof(phdr);
 376
 377         /* Remove unwanted PT_NOTE program headers. */
 378         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
 379         *elfsz = *elfsz - i;
 380         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
 381         memset(elfptr + *elfsz, 0, i);
 382         *elfsz = roundup(*elfsz, PAGE_SIZE);
 383
 384         /* Modify e_phnum to reflect merged headers. */
 385         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 386
 387         return 0;
 388 }
 389
 390 /* Add memory chunks represented by program headers to vmcore list. Also update
 391  * the new offset fields of exported program headers. */
 392 static int __init process_ptload_program_headers_elf64(char *elfptr,
 393                                                 size_t elfsz,
 394                                                 struct list_head *vc_list)
 395 {
 396         int i;
 397         Elf64_Ehdr *ehdr_ptr;
 398         Elf64_Phdr *phdr_ptr;
 399         loff_t vmcore_off;
 400         struct vmcore *new;
 401
 402         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 403         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 404
 405         /* First program header is PT_NOTE header. */
 406         vmcore_off = elfsz +
 407                         phdr_ptr->p_memsz; /* Note sections */
 408
 409         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 410                 if (phdr_ptr->p_type != PT_LOAD)
 411                         continue;
 412
 413                 /* Add this contiguous chunk of memory to vmcore list.*/
 414                 new = get_new_element();
 415                 if (!new)
 416                         return -ENOMEM;
 417                 new->paddr = phdr_ptr->p_offset;
 418                 new->size = phdr_ptr->p_memsz;
 419                 list_add_tail(&new->list, vc_list);
 420
 421                 /* Update the program header offset. */
 422                 phdr_ptr->p_offset = vmcore_off;
 423                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 424         }
 425         return 0;
 426 }
 427
 428 static int __init process_ptload_program_headers_elf32(char *elfptr,
 429                                                 size_t elfsz,
 430                                                 struct list_head *vc_list)
 431 {
 432         int i;
 433         Elf32_Ehdr *ehdr_ptr;
 434         Elf32_Phdr *phdr_ptr;
 435         loff_t vmcore_off;
 436         struct vmcore *new;
 437
 438         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 439         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
 440
 441         /* First program header is PT_NOTE header. */
 442         vmcore_off = elfsz +
 443                         phdr_ptr->p_memsz; /* Note sections */
 444
 445         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 446                 if (phdr_ptr->p_type != PT_LOAD)
 447                         continue;
 448
 449                 /* Add this contiguous chunk of memory to vmcore list.*/
 450                 new = get_new_element();
 451                 if (!new)
 452                         return -ENOMEM;
 453                 new->paddr = phdr_ptr->p_offset;
 454                 new->size = phdr_ptr->p_memsz;
 455                 list_add_tail(&new->list, vc_list);
 456
 457                 /* Update the program header offset */
 458                 phdr_ptr->p_offset = vmcore_off;
 459                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 460         }
 461         return 0;
 462 }
 463
 464 /* Sets offset fields of vmcore elements. */
 465 static void __init set_vmcore_list_offsets(size_t elfsz,
 466                                            struct list_head *vc_list)
 467 {
 468         loff_t vmcore_off;
 469         struct vmcore *m;
 470
 471         /* Skip Elf header and program headers. */
 472         vmcore_off = elfsz;
 473
 474         list_for_each_entry(m, vc_list, list) {
 475                 m->offset = vmcore_off;
 476                 vmcore_off += m->size;
 477         }
 478 }
 479
 480 static void free_elfcorebuf(void)
 481 {
 482         free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
 483         elfcorebuf = NULL;
 484 }
 485
 486 static int __init parse_crash_elf64_headers(void)
 487 {
 488         int rc=0;
 489         Elf64_Ehdr ehdr;
 490         u64 addr;
 491
 492         addr = elfcorehdr_addr;
 493
 494         /* Read Elf header */
 495         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
 496         if (rc < 0)
 497                 return rc;
 498
 499         /* Do some basic Verification. */
 500         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 501                 (ehdr.e_type != ET_CORE) ||
 502                 !vmcore_elf64_check_arch(&ehdr) ||
 503                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
 504                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 505                 ehdr.e_version != EV_CURRENT ||
 506                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
 507                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
 508                 ehdr.e_phnum == 0) {
 509                 pr_warn("Warning: Core image elf header is not sane\n");
 510                 return -EINVAL;
 511         }
 512
 513         /* Read in all elf headers. */
 514         elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
 515                                 ehdr.e_phnum * sizeof(Elf64_Phdr);
 516         elfcorebuf_sz = elfcorebuf_sz_orig;
 517         elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 518                                               get_order(elfcorebuf_sz_orig));
 519         if (!elfcorebuf)
 520                 return -ENOMEM;
 521         addr = elfcorehdr_addr;
 522         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0);
 523         if (rc < 0)
 524                 goto fail;
 525
 526         /* Merge all PT_NOTE headers into one. */
 527         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 528         if (rc)
 529                 goto fail;
 530         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
 531                                                         &vmcore_list);
 532         if (rc)
 533                 goto fail;
 534         set_vmcore_list_offsets(elfcorebuf_sz, &vmcore_list);
 535         return 0;
 536 fail:
 537         free_elfcorebuf();
 538         return rc;
 539 }
 540
 541 static int __init parse_crash_elf32_headers(void)
 542 {
 543         int rc=0;
 544         Elf32_Ehdr ehdr;
 545         u64 addr;
 546
 547         addr = elfcorehdr_addr;
 548
 549         /* Read Elf header */
 550         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
 551         if (rc < 0)
 552                 return rc;
 553
 554         /* Do some basic Verification. */
 555         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 556                 (ehdr.e_type != ET_CORE) ||
 557                 !elf_check_arch(&ehdr) ||
 558                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
 559                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 560                 ehdr.e_version != EV_CURRENT ||
 561                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
 562                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
 563                 ehdr.e_phnum == 0) {
 564                 pr_warn("Warning: Core image elf header is not sane\n");
 565                 return -EINVAL;
 566         }
 567
 568         /* Read in all elf headers. */
 569         elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
 570         elfcorebuf_sz = elfcorebuf_sz_orig;
 571         elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 572                                               get_order(elfcorebuf_sz_orig));
 573         if (!elfcorebuf)
 574                 return -ENOMEM;
 575         addr = elfcorehdr_addr;
 576         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0);
 577         if (rc < 0)
 578                 goto fail;
 579
 580         /* Merge all PT_NOTE headers into one. */
 581         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 582         if (rc)
 583                 goto fail;
 584         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
 585                                                                 &vmcore_list);
 586         if (rc)
 587                 goto fail;
 588         set_vmcore_list_offsets(elfcorebuf_sz, &vmcore_list);
 589         return 0;
 590 fail:
 591         free_elfcorebuf();
 592         return rc;
 593 }
 594
 595 static int __init parse_crash_elf_headers(void)
 596 {
 597         unsigned char e_ident[EI_NIDENT];
 598         u64 addr;
 599         int rc=0;
 600
 601         addr = elfcorehdr_addr;
 602         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
 603         if (rc < 0)
 604                 return rc;
 605         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
 606                 pr_warn("Warning: Core image elf header not found\n");
 607                 return -EINVAL;
 608         }
 609
 610         if (e_ident[EI_CLASS] == ELFCLASS64) {
 611                 rc = parse_crash_elf64_headers();
 612                 if (rc)
 613                         return rc;
 614
 615                 /* Determine vmcore size. */
 616                 vmcore_size = get_vmcore_size_elf64(elfcorebuf, elfcorebuf_sz);
 617         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
 618                 rc = parse_crash_elf32_headers();
 619                 if (rc)
 620                         return rc;
 621
 622                 /* Determine vmcore size. */
 623                 vmcore_size = get_vmcore_size_elf32(elfcorebuf, elfcorebuf_sz);
 624         } else {
 625                 pr_warn("Warning: Core image elf header is not sane\n");
 626                 return -EINVAL;
 627         }
 628         return 0;
 629 }
 630
 631 /* Init function for vmcore module. */
 632 static int __init vmcore_init(void)
 633 {
 634         int rc = 0;
 635
 636         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
 637         if (!(is_vmcore_usable()))
 638                 return rc;
 639         rc = parse_crash_elf_headers();
 640         if (rc) {
 641                 pr_warn("Kdump: vmcore not initialized\n");
 642                 return rc;
 643         }
 644
 645         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
 646         if (proc_vmcore)
 647                 proc_vmcore->size = vmcore_size;
 648         return 0;
 649 }
 650 module_init(vmcore_init)
 651
 652 /* Cleanup function for vmcore module. */
 653 void vmcore_cleanup(void)
 654 {
 655         struct list_head *pos, *next;
 656
 657         if (proc_vmcore) {
 658                 proc_remove(proc_vmcore);
 659                 proc_vmcore = NULL;
 660         }
 661
 662         /* clear the vmcore list. */
 663         list_for_each_safe(pos, next, &vmcore_list) {
 664                 struct vmcore *m;
 665
 666                 m = list_entry(pos, struct vmcore, list);
 667                 list_del(&m->list);
 668                 kfree(m);
 669         }
 670         free_elfcorebuf();
 671 }
 672 EXPORT_SYMBOL_GPL(vmcore_cleanup);