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/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
  26 /* List representing chunks of contiguous memory areas and their offsets in
  27  * vmcore file.
  28  */
  29 static LIST_HEAD(vmcore_list);
  30
  31 /* Stores the pointer to the buffer containing kernel elf core headers. */
  32 static char *elfcorebuf;
  33 static size_t elfcorebuf_sz;
  34
  35 /* Total size of vmcore file. */
  36 static u64 vmcore_size;
  37
  38 static struct proc_dir_entry *proc_vmcore = NULL;
  39
  40 /*
  41  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  42  * The called function has to take care of module refcounting.
  43  */
  44 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
  45
  46 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
  47 {
  48         if (oldmem_pfn_is_ram)
  49                 return -EBUSY;
  50         oldmem_pfn_is_ram = fn;
  51         return 0;
  52 }
  53 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
  54
  55 void unregister_oldmem_pfn_is_ram(void)
  56 {
  57         oldmem_pfn_is_ram = NULL;
  58         wmb();
  59 }
  60 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
  61
  62 static int pfn_is_ram(unsigned long pfn)
  63 {
  64         int (*fn)(unsigned long pfn);
  65         /* pfn is ram unless fn() checks pagetype */
  66         int ret = 1;
  67
  68         /*
  69          * Ask hypervisor if the pfn is really ram.
  70          * A ballooned page contains no data and reading from such a page
  71          * will cause high load in the hypervisor.
  72          */
  73         fn = oldmem_pfn_is_ram;
  74         if (fn)
  75                 ret = fn(pfn);
  76
  77         return ret;
  78 }
  79
  80 /* Reads a page from the oldmem device from given offset. */
  81 static ssize_t read_from_oldmem(char *buf, size_t count,
  82                                 u64 *ppos, int userbuf)
  83 {
  84         unsigned long pfn, offset;
  85         size_t nr_bytes;
  86         ssize_t read = 0, tmp;
  87
  88         if (!count)
  89                 return 0;
  90
  91         offset = (unsigned long)(*ppos % PAGE_SIZE);
  92         pfn = (unsigned long)(*ppos / PAGE_SIZE);
  93
  94         do {
  95                 if (count > (PAGE_SIZE - offset))
  96                         nr_bytes = PAGE_SIZE - offset;
  97                 else
  98                         nr_bytes = count;
  99
 100                 /* If pfn is not ram, return zeros for sparse dump files */
 101                 if (pfn_is_ram(pfn) == 0)
 102                         memset(buf, 0, nr_bytes);
 103                 else {
 104                         tmp = copy_oldmem_page(pfn, buf, nr_bytes,
 105                                                 offset, userbuf);
 106                         if (tmp < 0)
 107                                 return tmp;
 108                 }
 109                 *ppos += nr_bytes;
 110                 count -= nr_bytes;
 111                 buf += nr_bytes;
 112                 read += nr_bytes;
 113                 ++pfn;
 114                 offset = 0;
 115         } while (count);
 116
 117         return read;
 118 }
 119
 120 /* Maps vmcore file offset to respective physical address in memroy. */
 121 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
 122                                         struct vmcore **m_ptr)
 123 {
 124         struct vmcore *m;
 125         u64 paddr;
 126
 127         list_for_each_entry(m, vc_list, list) {
 128                 u64 start, end;
 129                 start = m->offset;
 130                 end = m->offset + m->size - 1;
 131                 if (offset >= start && offset <= end) {
 132                         paddr = m->paddr + offset - start;
 133                         *m_ptr = m;
 134                         return paddr;
 135                 }
 136         }
 137         *m_ptr = NULL;
 138         return 0;
 139 }
 140
 141 /* Read from the ELF header and then the crash dump. On error, negative value is
 142  * returned otherwise number of bytes read are returned.
 143  */
 144 static ssize_t read_vmcore(struct file *file, char __user *buffer,
 145                                 size_t buflen, loff_t *fpos)
 146 {
 147         ssize_t acc = 0, tmp;
 148         size_t tsz;
 149         u64 start, nr_bytes;
 150         struct vmcore *curr_m = NULL;
 151
 152         if (buflen == 0 || *fpos >= vmcore_size)
 153                 return 0;
 154
 155         /* trim buflen to not go beyond EOF */
 156         if (buflen > vmcore_size - *fpos)
 157                 buflen = vmcore_size - *fpos;
 158
 159         /* Read ELF core header */
 160         if (*fpos < elfcorebuf_sz) {
 161                 tsz = elfcorebuf_sz - *fpos;
 162                 if (buflen < tsz)
 163                         tsz = buflen;
 164                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
 165                         return -EFAULT;
 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         start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
 177         if (!curr_m)
 178                 return -EINVAL;
 179
 180         while (buflen) {
 181                 tsz = min_t(size_t, buflen, PAGE_SIZE - (start & ~PAGE_MASK));
 182
 183                 /* Calculate left bytes in current memory segment. */
 184                 nr_bytes = (curr_m->size - (start - curr_m->paddr));
 185                 if (tsz > nr_bytes)
 186                         tsz = nr_bytes;
 187
 188                 tmp = read_from_oldmem(buffer, tsz, &start, 1);
 189                 if (tmp < 0)
 190                         return tmp;
 191                 buflen -= tsz;
 192                 *fpos += tsz;
 193                 buffer += tsz;
 194                 acc += tsz;
 195                 if (start >= (curr_m->paddr + curr_m->size)) {
 196                         if (curr_m->list.next == &vmcore_list)
 197                                 return acc;     /*EOF*/
 198                         curr_m = list_entry(curr_m->list.next,
 199                                                 struct vmcore, list);
 200                         start = curr_m->paddr;
 201                 }
 202         }
 203         return acc;
 204 }
 205
 206 static const struct file_operations proc_vmcore_operations = {
 207         .read           = read_vmcore,
 208         .llseek         = default_llseek,
 209 };
 210
 211 static struct vmcore* __init get_new_element(void)
 212 {
 213         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
 214 }
 215
 216 static u64 __init get_vmcore_size_elf64(char *elfptr)
 217 {
 218         int i;
 219         u64 size;
 220         Elf64_Ehdr *ehdr_ptr;
 221         Elf64_Phdr *phdr_ptr;
 222
 223         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 224         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 225         size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
 226         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 227                 size += phdr_ptr->p_memsz;
 228                 phdr_ptr++;
 229         }
 230         return size;
 231 }
 232
 233 static u64 __init get_vmcore_size_elf32(char *elfptr)
 234 {
 235         int i;
 236         u64 size;
 237         Elf32_Ehdr *ehdr_ptr;
 238         Elf32_Phdr *phdr_ptr;
 239
 240         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 241         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 242         size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
 243         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 244                 size += phdr_ptr->p_memsz;
 245                 phdr_ptr++;
 246         }
 247         return size;
 248 }
 249
 250 /* Merges all the PT_NOTE headers into one. */
 251 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 252                                                 struct list_head *vc_list)
 253 {
 254         int i, nr_ptnote=0, rc=0;
 255         char *tmp;
 256         Elf64_Ehdr *ehdr_ptr;
 257         Elf64_Phdr phdr, *phdr_ptr;
 258         Elf64_Nhdr *nhdr_ptr;
 259         u64 phdr_sz = 0, note_off;
 260
 261         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 262         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 263         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 264                 int j;
 265                 void *notes_section;
 266                 struct vmcore *new;
 267                 u64 offset, max_sz, sz, real_sz = 0;
 268                 if (phdr_ptr->p_type != PT_NOTE)
 269                         continue;
 270                 nr_ptnote++;
 271                 max_sz = phdr_ptr->p_memsz;
 272                 offset = phdr_ptr->p_offset;
 273                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 274                 if (!notes_section)
 275                         return -ENOMEM;
 276                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 277                 if (rc < 0) {
 278                         kfree(notes_section);
 279                         return rc;
 280                 }
 281                 nhdr_ptr = notes_section;
 282                 for (j = 0; j < max_sz; j += sz) {
 283                         if (nhdr_ptr->n_namesz == 0)
 284                                 break;
 285                         sz = sizeof(Elf64_Nhdr) +
 286                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 287                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 288                         real_sz += sz;
 289                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 290                 }
 291
 292                 /* Add this contiguous chunk of notes section to vmcore list.*/
 293                 new = get_new_element();
 294                 if (!new) {
 295                         kfree(notes_section);
 296                         return -ENOMEM;
 297                 }
 298                 new->paddr = phdr_ptr->p_offset;
 299                 new->size = real_sz;
 300                 list_add_tail(&new->list, vc_list);
 301                 phdr_sz += real_sz;
 302                 kfree(notes_section);
 303         }
 304
 305         /* Prepare merged PT_NOTE program header. */
 306         phdr.p_type    = PT_NOTE;
 307         phdr.p_flags   = 0;
 308         note_off = sizeof(Elf64_Ehdr) +
 309                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 310         phdr.p_offset  = note_off;
 311         phdr.p_vaddr   = phdr.p_paddr = 0;
 312         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 313         phdr.p_align   = 0;
 314
 315         /* Add merged PT_NOTE program header*/
 316         tmp = elfptr + sizeof(Elf64_Ehdr);
 317         memcpy(tmp, &phdr, sizeof(phdr));
 318         tmp += sizeof(phdr);
 319
 320         /* Remove unwanted PT_NOTE program headers. */
 321         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 322         *elfsz = *elfsz - i;
 323         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 324
 325         /* Modify e_phnum to reflect merged headers. */
 326         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 327
 328         return 0;
 329 }
 330
 331 /* Merges all the PT_NOTE headers into one. */
 332 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 333                                                 struct list_head *vc_list)
 334 {
 335         int i, nr_ptnote=0, rc=0;
 336         char *tmp;
 337         Elf32_Ehdr *ehdr_ptr;
 338         Elf32_Phdr phdr, *phdr_ptr;
 339         Elf32_Nhdr *nhdr_ptr;
 340         u64 phdr_sz = 0, note_off;
 341
 342         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 343         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 344         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 345                 int j;
 346                 void *notes_section;
 347                 struct vmcore *new;
 348                 u64 offset, max_sz, sz, real_sz = 0;
 349                 if (phdr_ptr->p_type != PT_NOTE)
 350                         continue;
 351                 nr_ptnote++;
 352                 max_sz = phdr_ptr->p_memsz;
 353                 offset = phdr_ptr->p_offset;
 354                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 355                 if (!notes_section)
 356                         return -ENOMEM;
 357                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 358                 if (rc < 0) {
 359                         kfree(notes_section);
 360                         return rc;
 361                 }
 362                 nhdr_ptr = notes_section;
 363                 for (j = 0; j < max_sz; j += sz) {
 364                         if (nhdr_ptr->n_namesz == 0)
 365                                 break;
 366                         sz = sizeof(Elf32_Nhdr) +
 367                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 368                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 369                         real_sz += sz;
 370                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 371                 }
 372
 373                 /* Add this contiguous chunk of notes section to vmcore list.*/
 374                 new = get_new_element();
 375                 if (!new) {
 376                         kfree(notes_section);
 377                         return -ENOMEM;
 378                 }
 379                 new->paddr = phdr_ptr->p_offset;
 380                 new->size = real_sz;
 381                 list_add_tail(&new->list, vc_list);
 382                 phdr_sz += real_sz;
 383                 kfree(notes_section);
 384         }
 385
 386         /* Prepare merged PT_NOTE program header. */
 387         phdr.p_type    = PT_NOTE;
 388         phdr.p_flags   = 0;
 389         note_off = sizeof(Elf32_Ehdr) +
 390                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
 391         phdr.p_offset  = note_off;
 392         phdr.p_vaddr   = phdr.p_paddr = 0;
 393         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 394         phdr.p_align   = 0;
 395
 396         /* Add merged PT_NOTE program header*/
 397         tmp = elfptr + sizeof(Elf32_Ehdr);
 398         memcpy(tmp, &phdr, sizeof(phdr));
 399         tmp += sizeof(phdr);
 400
 401         /* Remove unwanted PT_NOTE program headers. */
 402         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
 403         *elfsz = *elfsz - i;
 404         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
 405
 406         /* Modify e_phnum to reflect merged headers. */
 407         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 408
 409         return 0;
 410 }
 411
 412 /* Add memory chunks represented by program headers to vmcore list. Also update
 413  * the new offset fields of exported program headers. */
 414 static int __init process_ptload_program_headers_elf64(char *elfptr,
 415                                                 size_t elfsz,
 416                                                 struct list_head *vc_list)
 417 {
 418         int i;
 419         Elf64_Ehdr *ehdr_ptr;
 420         Elf64_Phdr *phdr_ptr;
 421         loff_t vmcore_off;
 422         struct vmcore *new;
 423
 424         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 425         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 426
 427         /* First program header is PT_NOTE header. */
 428         vmcore_off = sizeof(Elf64_Ehdr) +
 429                         (ehdr_ptr->e_phnum) * sizeof(Elf64_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 static int __init process_ptload_program_headers_elf32(char *elfptr,
 452                                                 size_t elfsz,
 453                                                 struct list_head *vc_list)
 454 {
 455         int i;
 456         Elf32_Ehdr *ehdr_ptr;
 457         Elf32_Phdr *phdr_ptr;
 458         loff_t vmcore_off;
 459         struct vmcore *new;
 460
 461         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 462         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
 463
 464         /* First program header is PT_NOTE header. */
 465         vmcore_off = sizeof(Elf32_Ehdr) +
 466                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
 467                         phdr_ptr->p_memsz; /* Note sections */
 468
 469         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 470                 if (phdr_ptr->p_type != PT_LOAD)
 471                         continue;
 472
 473                 /* Add this contiguous chunk of memory to vmcore list.*/
 474                 new = get_new_element();
 475                 if (!new)
 476                         return -ENOMEM;
 477                 new->paddr = phdr_ptr->p_offset;
 478                 new->size = phdr_ptr->p_memsz;
 479                 list_add_tail(&new->list, vc_list);
 480
 481                 /* Update the program header offset */
 482                 phdr_ptr->p_offset = vmcore_off;
 483                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 484         }
 485         return 0;
 486 }
 487
 488 /* Sets offset fields of vmcore elements. */
 489 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
 490                                                 struct list_head *vc_list)
 491 {
 492         loff_t vmcore_off;
 493         Elf64_Ehdr *ehdr_ptr;
 494         struct vmcore *m;
 495
 496         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 497
 498         /* Skip Elf header and program headers. */
 499         vmcore_off = sizeof(Elf64_Ehdr) +
 500                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
 501
 502         list_for_each_entry(m, vc_list, list) {
 503                 m->offset = vmcore_off;
 504                 vmcore_off += m->size;
 505         }
 506 }
 507
 508 /* Sets offset fields of vmcore elements. */
 509 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
 510                                                 struct list_head *vc_list)
 511 {
 512         loff_t vmcore_off;
 513         Elf32_Ehdr *ehdr_ptr;
 514         struct vmcore *m;
 515
 516         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 517
 518         /* Skip Elf header and program headers. */
 519         vmcore_off = sizeof(Elf32_Ehdr) +
 520                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
 521
 522         list_for_each_entry(m, vc_list, list) {
 523                 m->offset = vmcore_off;
 524                 vmcore_off += m->size;
 525         }
 526 }
 527
 528 static int __init parse_crash_elf64_headers(void)
 529 {
 530         int rc=0;
 531         Elf64_Ehdr ehdr;
 532         u64 addr;
 533
 534         addr = elfcorehdr_addr;
 535
 536         /* Read Elf header */
 537         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
 538         if (rc < 0)
 539                 return rc;
 540
 541         /* Do some basic Verification. */
 542         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 543                 (ehdr.e_type != ET_CORE) ||
 544                 !vmcore_elf64_check_arch(&ehdr) ||
 545                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
 546                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 547                 ehdr.e_version != EV_CURRENT ||
 548                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
 549                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
 550                 ehdr.e_phnum == 0) {
 551                 pr_warn("Warning: Core image elf header is not sane\n");
 552                 return -EINVAL;
 553         }
 554
 555         /* Read in all elf headers. */
 556         elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
 557         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 558         if (!elfcorebuf)
 559                 return -ENOMEM;
 560         addr = elfcorehdr_addr;
 561         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 562         if (rc < 0) {
 563                 kfree(elfcorebuf);
 564                 return rc;
 565         }
 566
 567         /* Merge all PT_NOTE headers into one. */
 568         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 569         if (rc) {
 570                 kfree(elfcorebuf);
 571                 return rc;
 572         }
 573         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
 574                                                         &vmcore_list);
 575         if (rc) {
 576                 kfree(elfcorebuf);
 577                 return rc;
 578         }
 579         set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
 580         return 0;
 581 }
 582
 583 static int __init parse_crash_elf32_headers(void)
 584 {
 585         int rc=0;
 586         Elf32_Ehdr ehdr;
 587         u64 addr;
 588
 589         addr = elfcorehdr_addr;
 590
 591         /* Read Elf header */
 592         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
 593         if (rc < 0)
 594                 return rc;
 595
 596         /* Do some basic Verification. */
 597         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 598                 (ehdr.e_type != ET_CORE) ||
 599                 !elf_check_arch(&ehdr) ||
 600                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
 601                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 602                 ehdr.e_version != EV_CURRENT ||
 603                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
 604                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
 605                 ehdr.e_phnum == 0) {
 606                 pr_warn("Warning: Core image elf header is not sane\n");
 607                 return -EINVAL;
 608         }
 609
 610         /* Read in all elf headers. */
 611         elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
 612         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 613         if (!elfcorebuf)
 614                 return -ENOMEM;
 615         addr = elfcorehdr_addr;
 616         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 617         if (rc < 0) {
 618                 kfree(elfcorebuf);
 619                 return rc;
 620         }
 621
 622         /* Merge all PT_NOTE headers into one. */
 623         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 624         if (rc) {
 625                 kfree(elfcorebuf);
 626                 return rc;
 627         }
 628         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
 629                                                                 &vmcore_list);
 630         if (rc) {
 631                 kfree(elfcorebuf);
 632                 return rc;
 633         }
 634         set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
 635         return 0;
 636 }
 637
 638 static int __init parse_crash_elf_headers(void)
 639 {
 640         unsigned char e_ident[EI_NIDENT];
 641         u64 addr;
 642         int rc=0;
 643
 644         addr = elfcorehdr_addr;
 645         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
 646         if (rc < 0)
 647                 return rc;
 648         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
 649                 pr_warn("Warning: Core image elf header not found\n");
 650                 return -EINVAL;
 651         }
 652
 653         if (e_ident[EI_CLASS] == ELFCLASS64) {
 654                 rc = parse_crash_elf64_headers();
 655                 if (rc)
 656                         return rc;
 657
 658                 /* Determine vmcore size. */
 659                 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
 660         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
 661                 rc = parse_crash_elf32_headers();
 662                 if (rc)
 663                         return rc;
 664
 665                 /* Determine vmcore size. */
 666                 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
 667         } else {
 668                 pr_warn("Warning: Core image elf header is not sane\n");
 669                 return -EINVAL;
 670         }
 671         return 0;
 672 }
 673
 674 /* Init function for vmcore module. */
 675 static int __init vmcore_init(void)
 676 {
 677         int rc = 0;
 678
 679         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
 680         if (!(is_vmcore_usable()))
 681                 return rc;
 682         rc = parse_crash_elf_headers();
 683         if (rc) {
 684                 pr_warn("Kdump: vmcore not initialized\n");
 685                 return rc;
 686         }
 687
 688         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
 689         if (proc_vmcore)
 690                 proc_vmcore->size = vmcore_size;
 691         return 0;
 692 }
 693 module_init(vmcore_init)
 694
 695 /* Cleanup function for vmcore module. */
 696 void vmcore_cleanup(void)
 697 {
 698         struct list_head *pos, *next;
 699
 700         if (proc_vmcore) {
 701                 remove_proc_entry(proc_vmcore->name, proc_vmcore->parent);
 702                 proc_vmcore = NULL;
 703         }
 704
 705         /* clear the vmcore list. */
 706         list_for_each_safe(pos, next, &vmcore_list) {
 707                 struct vmcore *m;
 708
 709                 m = list_entry(pos, struct vmcore, list);
 710                 list_del(&m->list);
 711                 kfree(m);
 712         }
 713         kfree(elfcorebuf);
 714         elfcorebuf = NULL;
 715 }
 716 EXPORT_SYMBOL_GPL(vmcore_cleanup);