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
  36 /* Total size of vmcore file. */
  37 static u64 vmcore_size;
  38
  39 static struct proc_dir_entry *proc_vmcore = NULL;
  40
  41 /*
  42  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  43  * The called function has to take care of module refcounting.
  44  */
  45 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
  46
  47 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
  48 {
  49         if (oldmem_pfn_is_ram)
  50                 return -EBUSY;
  51         oldmem_pfn_is_ram = fn;
  52         return 0;
  53 }
  54 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
  55
  56 void unregister_oldmem_pfn_is_ram(void)
  57 {
  58         oldmem_pfn_is_ram = NULL;
  59         wmb();
  60 }
  61 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
  62
  63 static int pfn_is_ram(unsigned long pfn)
  64 {
  65         int (*fn)(unsigned long pfn);
  66         /* pfn is ram unless fn() checks pagetype */
  67         int ret = 1;
  68
  69         /*
  70          * Ask hypervisor if the pfn is really ram.
  71          * A ballooned page contains no data and reading from such a page
  72          * will cause high load in the hypervisor.
  73          */
  74         fn = oldmem_pfn_is_ram;
  75         if (fn)
  76                 ret = fn(pfn);
  77
  78         return ret;
  79 }
  80
  81 /* Reads a page from the oldmem device from given offset. */
  82 static ssize_t read_from_oldmem(char *buf, size_t count,
  83                                 u64 *ppos, int userbuf)
  84 {
  85         unsigned long pfn, offset;
  86         size_t nr_bytes;
  87         ssize_t read = 0, tmp;
  88
  89         if (!count)
  90                 return 0;
  91
  92         offset = (unsigned long)(*ppos % PAGE_SIZE);
  93         pfn = (unsigned long)(*ppos / PAGE_SIZE);
  94
  95         do {
  96                 if (count > (PAGE_SIZE - offset))
  97                         nr_bytes = PAGE_SIZE - offset;
  98                 else
  99                         nr_bytes = count;
 100
 101                 /* If pfn is not ram, return zeros for sparse dump files */
 102                 if (pfn_is_ram(pfn) == 0)
 103                         memset(buf, 0, nr_bytes);
 104                 else {
 105                         tmp = copy_oldmem_page(pfn, buf, nr_bytes,
 106                                                 offset, userbuf);
 107                         if (tmp < 0)
 108                                 return tmp;
 109                 }
 110                 *ppos += nr_bytes;
 111                 count -= nr_bytes;
 112                 buf += nr_bytes;
 113                 read += nr_bytes;
 114                 ++pfn;
 115                 offset = 0;
 116         } while (count);
 117
 118         return read;
 119 }
 120
 121 /* Maps vmcore file offset to respective physical address in memroy. */
 122 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
 123                                         struct vmcore **m_ptr)
 124 {
 125         struct vmcore *m;
 126         u64 paddr;
 127
 128         list_for_each_entry(m, vc_list, list) {
 129                 u64 start, end;
 130                 start = m->offset;
 131                 end = m->offset + m->size - 1;
 132                 if (offset >= start && offset <= end) {
 133                         paddr = m->paddr + offset - start;
 134                         *m_ptr = m;
 135                         return paddr;
 136                 }
 137         }
 138         *m_ptr = NULL;
 139         return 0;
 140 }
 141
 142 /* Read from the ELF header and then the crash dump. On error, negative value is
 143  * returned otherwise number of bytes read are returned.
 144  */
 145 static ssize_t read_vmcore(struct file *file, char __user *buffer,
 146                                 size_t buflen, loff_t *fpos)
 147 {
 148         ssize_t acc = 0, tmp;
 149         size_t tsz;
 150         u64 start, nr_bytes;
 151         struct vmcore *curr_m = NULL;
 152
 153         if (buflen == 0 || *fpos >= vmcore_size)
 154                 return 0;
 155
 156         /* trim buflen to not go beyond EOF */
 157         if (buflen > vmcore_size - *fpos)
 158                 buflen = vmcore_size - *fpos;
 159
 160         /* Read ELF core header */
 161         if (*fpos < elfcorebuf_sz) {
 162                 tsz = elfcorebuf_sz - *fpos;
 163                 if (buflen < tsz)
 164                         tsz = buflen;
 165                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
 166                         return -EFAULT;
 167                 buflen -= tsz;
 168                 *fpos += tsz;
 169                 buffer += tsz;
 170                 acc += tsz;
 171
 172                 /* leave now if filled buffer already */
 173                 if (buflen == 0)
 174                         return acc;
 175         }
 176
 177         start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
 178         if (!curr_m)
 179                 return -EINVAL;
 180
 181         while (buflen) {
 182                 tsz = min_t(size_t, buflen, PAGE_SIZE - (start & ~PAGE_MASK));
 183
 184                 /* Calculate left bytes in current memory segment. */
 185                 nr_bytes = (curr_m->size - (start - curr_m->paddr));
 186                 if (tsz > nr_bytes)
 187                         tsz = nr_bytes;
 188
 189                 tmp = read_from_oldmem(buffer, tsz, &start, 1);
 190                 if (tmp < 0)
 191                         return tmp;
 192                 buflen -= tsz;
 193                 *fpos += tsz;
 194                 buffer += tsz;
 195                 acc += tsz;
 196                 if (start >= (curr_m->paddr + curr_m->size)) {
 197                         if (curr_m->list.next == &vmcore_list)
 198                                 return acc;     /*EOF*/
 199                         curr_m = list_entry(curr_m->list.next,
 200                                                 struct vmcore, list);
 201                         start = curr_m->paddr;
 202                 }
 203         }
 204         return acc;
 205 }
 206
 207 static const struct file_operations proc_vmcore_operations = {
 208         .read           = read_vmcore,
 209         .llseek         = default_llseek,
 210 };
 211
 212 static struct vmcore* __init get_new_element(void)
 213 {
 214         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
 215 }
 216
 217 static u64 __init get_vmcore_size_elf64(char *elfptr)
 218 {
 219         int i;
 220         u64 size;
 221         Elf64_Ehdr *ehdr_ptr;
 222         Elf64_Phdr *phdr_ptr;
 223
 224         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 225         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 226         size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
 227         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 228                 size += phdr_ptr->p_memsz;
 229                 phdr_ptr++;
 230         }
 231         return size;
 232 }
 233
 234 static u64 __init get_vmcore_size_elf32(char *elfptr)
 235 {
 236         int i;
 237         u64 size;
 238         Elf32_Ehdr *ehdr_ptr;
 239         Elf32_Phdr *phdr_ptr;
 240
 241         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 242         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 243         size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
 244         for (i = 0; i < ehdr_ptr->e_phnum; i++) {
 245                 size += phdr_ptr->p_memsz;
 246                 phdr_ptr++;
 247         }
 248         return size;
 249 }
 250
 251 /* Merges all the PT_NOTE headers into one. */
 252 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 253                                                 struct list_head *vc_list)
 254 {
 255         int i, nr_ptnote=0, rc=0;
 256         char *tmp;
 257         Elf64_Ehdr *ehdr_ptr;
 258         Elf64_Phdr phdr, *phdr_ptr;
 259         Elf64_Nhdr *nhdr_ptr;
 260         u64 phdr_sz = 0, note_off;
 261
 262         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 263         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
 264         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 265                 int j;
 266                 void *notes_section;
 267                 struct vmcore *new;
 268                 u64 offset, max_sz, sz, real_sz = 0;
 269                 if (phdr_ptr->p_type != PT_NOTE)
 270                         continue;
 271                 nr_ptnote++;
 272                 max_sz = phdr_ptr->p_memsz;
 273                 offset = phdr_ptr->p_offset;
 274                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 275                 if (!notes_section)
 276                         return -ENOMEM;
 277                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 278                 if (rc < 0) {
 279                         kfree(notes_section);
 280                         return rc;
 281                 }
 282                 nhdr_ptr = notes_section;
 283                 for (j = 0; j < max_sz; j += sz) {
 284                         if (nhdr_ptr->n_namesz == 0)
 285                                 break;
 286                         sz = sizeof(Elf64_Nhdr) +
 287                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 288                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 289                         real_sz += sz;
 290                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 291                 }
 292
 293                 /* Add this contiguous chunk of notes section to vmcore list.*/
 294                 new = get_new_element();
 295                 if (!new) {
 296                         kfree(notes_section);
 297                         return -ENOMEM;
 298                 }
 299                 new->paddr = phdr_ptr->p_offset;
 300                 new->size = real_sz;
 301                 list_add_tail(&new->list, vc_list);
 302                 phdr_sz += real_sz;
 303                 kfree(notes_section);
 304         }
 305
 306         /* Prepare merged PT_NOTE program header. */
 307         phdr.p_type    = PT_NOTE;
 308         phdr.p_flags   = 0;
 309         note_off = sizeof(Elf64_Ehdr) +
 310                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 311         phdr.p_offset  = note_off;
 312         phdr.p_vaddr   = phdr.p_paddr = 0;
 313         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 314         phdr.p_align   = 0;
 315
 316         /* Add merged PT_NOTE program header*/
 317         tmp = elfptr + sizeof(Elf64_Ehdr);
 318         memcpy(tmp, &phdr, sizeof(phdr));
 319         tmp += sizeof(phdr);
 320
 321         /* Remove unwanted PT_NOTE program headers. */
 322         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 323         *elfsz = *elfsz - i;
 324         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 325
 326         /* Modify e_phnum to reflect merged headers. */
 327         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 328
 329         return 0;
 330 }
 331
 332 /* Merges all the PT_NOTE headers into one. */
 333 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 334                                                 struct list_head *vc_list)
 335 {
 336         int i, nr_ptnote=0, rc=0;
 337         char *tmp;
 338         Elf32_Ehdr *ehdr_ptr;
 339         Elf32_Phdr phdr, *phdr_ptr;
 340         Elf32_Nhdr *nhdr_ptr;
 341         u64 phdr_sz = 0, note_off;
 342
 343         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 344         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
 345         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 346                 int j;
 347                 void *notes_section;
 348                 struct vmcore *new;
 349                 u64 offset, max_sz, sz, real_sz = 0;
 350                 if (phdr_ptr->p_type != PT_NOTE)
 351                         continue;
 352                 nr_ptnote++;
 353                 max_sz = phdr_ptr->p_memsz;
 354                 offset = phdr_ptr->p_offset;
 355                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 356                 if (!notes_section)
 357                         return -ENOMEM;
 358                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 359                 if (rc < 0) {
 360                         kfree(notes_section);
 361                         return rc;
 362                 }
 363                 nhdr_ptr = notes_section;
 364                 for (j = 0; j < max_sz; j += sz) {
 365                         if (nhdr_ptr->n_namesz == 0)
 366                                 break;
 367                         sz = sizeof(Elf32_Nhdr) +
 368                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 369                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 370                         real_sz += sz;
 371                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 372                 }
 373
 374                 /* Add this contiguous chunk of notes section to vmcore list.*/
 375                 new = get_new_element();
 376                 if (!new) {
 377                         kfree(notes_section);
 378                         return -ENOMEM;
 379                 }
 380                 new->paddr = phdr_ptr->p_offset;
 381                 new->size = real_sz;
 382                 list_add_tail(&new->list, vc_list);
 383                 phdr_sz += real_sz;
 384                 kfree(notes_section);
 385         }
 386
 387         /* Prepare merged PT_NOTE program header. */
 388         phdr.p_type    = PT_NOTE;
 389         phdr.p_flags   = 0;
 390         note_off = sizeof(Elf32_Ehdr) +
 391                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
 392         phdr.p_offset  = note_off;
 393         phdr.p_vaddr   = phdr.p_paddr = 0;
 394         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 395         phdr.p_align   = 0;
 396
 397         /* Add merged PT_NOTE program header*/
 398         tmp = elfptr + sizeof(Elf32_Ehdr);
 399         memcpy(tmp, &phdr, sizeof(phdr));
 400         tmp += sizeof(phdr);
 401
 402         /* Remove unwanted PT_NOTE program headers. */
 403         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
 404         *elfsz = *elfsz - i;
 405         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
 406
 407         /* Modify e_phnum to reflect merged headers. */
 408         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 409
 410         return 0;
 411 }
 412
 413 /* Add memory chunks represented by program headers to vmcore list. Also update
 414  * the new offset fields of exported program headers. */
 415 static int __init process_ptload_program_headers_elf64(char *elfptr,
 416                                                 size_t elfsz,
 417                                                 struct list_head *vc_list)
 418 {
 419         int i;
 420         Elf64_Ehdr *ehdr_ptr;
 421         Elf64_Phdr *phdr_ptr;
 422         loff_t vmcore_off;
 423         struct vmcore *new;
 424
 425         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 426         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 427
 428         /* First program header is PT_NOTE header. */
 429         vmcore_off = sizeof(Elf64_Ehdr) +
 430                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
 431                         phdr_ptr->p_memsz; /* Note sections */
 432
 433         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 434                 if (phdr_ptr->p_type != PT_LOAD)
 435                         continue;
 436
 437                 /* Add this contiguous chunk of memory to vmcore list.*/
 438                 new = get_new_element();
 439                 if (!new)
 440                         return -ENOMEM;
 441                 new->paddr = phdr_ptr->p_offset;
 442                 new->size = phdr_ptr->p_memsz;
 443                 list_add_tail(&new->list, vc_list);
 444
 445                 /* Update the program header offset. */
 446                 phdr_ptr->p_offset = vmcore_off;
 447                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 448         }
 449         return 0;
 450 }
 451
 452 static int __init process_ptload_program_headers_elf32(char *elfptr,
 453                                                 size_t elfsz,
 454                                                 struct list_head *vc_list)
 455 {
 456         int i;
 457         Elf32_Ehdr *ehdr_ptr;
 458         Elf32_Phdr *phdr_ptr;
 459         loff_t vmcore_off;
 460         struct vmcore *new;
 461
 462         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 463         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
 464
 465         /* First program header is PT_NOTE header. */
 466         vmcore_off = sizeof(Elf32_Ehdr) +
 467                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
 468                         phdr_ptr->p_memsz; /* Note sections */
 469
 470         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 471                 if (phdr_ptr->p_type != PT_LOAD)
 472                         continue;
 473
 474                 /* Add this contiguous chunk of memory to vmcore list.*/
 475                 new = get_new_element();
 476                 if (!new)
 477                         return -ENOMEM;
 478                 new->paddr = phdr_ptr->p_offset;
 479                 new->size = phdr_ptr->p_memsz;
 480                 list_add_tail(&new->list, vc_list);
 481
 482                 /* Update the program header offset */
 483                 phdr_ptr->p_offset = vmcore_off;
 484                 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
 485         }
 486         return 0;
 487 }
 488
 489 /* Sets offset fields of vmcore elements. */
 490 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
 491                                                 struct list_head *vc_list)
 492 {
 493         loff_t vmcore_off;
 494         Elf64_Ehdr *ehdr_ptr;
 495         struct vmcore *m;
 496
 497         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 498
 499         /* Skip Elf header and program headers. */
 500         vmcore_off = sizeof(Elf64_Ehdr) +
 501                         (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
 502
 503         list_for_each_entry(m, vc_list, list) {
 504                 m->offset = vmcore_off;
 505                 vmcore_off += m->size;
 506         }
 507 }
 508
 509 /* Sets offset fields of vmcore elements. */
 510 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
 511                                                 struct list_head *vc_list)
 512 {
 513         loff_t vmcore_off;
 514         Elf32_Ehdr *ehdr_ptr;
 515         struct vmcore *m;
 516
 517         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 518
 519         /* Skip Elf header and program headers. */
 520         vmcore_off = sizeof(Elf32_Ehdr) +
 521                         (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
 522
 523         list_for_each_entry(m, vc_list, list) {
 524                 m->offset = vmcore_off;
 525                 vmcore_off += m->size;
 526         }
 527 }
 528
 529 static int __init parse_crash_elf64_headers(void)
 530 {
 531         int rc=0;
 532         Elf64_Ehdr ehdr;
 533         u64 addr;
 534
 535         addr = elfcorehdr_addr;
 536
 537         /* Read Elf header */
 538         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
 539         if (rc < 0)
 540                 return rc;
 541
 542         /* Do some basic Verification. */
 543         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 544                 (ehdr.e_type != ET_CORE) ||
 545                 !vmcore_elf64_check_arch(&ehdr) ||
 546                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
 547                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 548                 ehdr.e_version != EV_CURRENT ||
 549                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
 550                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
 551                 ehdr.e_phnum == 0) {
 552                 pr_warn("Warning: Core image elf header is not sane\n");
 553                 return -EINVAL;
 554         }
 555
 556         /* Read in all elf headers. */
 557         elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
 558         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 559         if (!elfcorebuf)
 560                 return -ENOMEM;
 561         addr = elfcorehdr_addr;
 562         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 563         if (rc < 0) {
 564                 kfree(elfcorebuf);
 565                 return rc;
 566         }
 567
 568         /* Merge all PT_NOTE headers into one. */
 569         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 570         if (rc) {
 571                 kfree(elfcorebuf);
 572                 return rc;
 573         }
 574         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
 575                                                         &vmcore_list);
 576         if (rc) {
 577                 kfree(elfcorebuf);
 578                 return rc;
 579         }
 580         set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
 581         return 0;
 582 }
 583
 584 static int __init parse_crash_elf32_headers(void)
 585 {
 586         int rc=0;
 587         Elf32_Ehdr ehdr;
 588         u64 addr;
 589
 590         addr = elfcorehdr_addr;
 591
 592         /* Read Elf header */
 593         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
 594         if (rc < 0)
 595                 return rc;
 596
 597         /* Do some basic Verification. */
 598         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 599                 (ehdr.e_type != ET_CORE) ||
 600                 !elf_check_arch(&ehdr) ||
 601                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
 602                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 603                 ehdr.e_version != EV_CURRENT ||
 604                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
 605                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
 606                 ehdr.e_phnum == 0) {
 607                 pr_warn("Warning: Core image elf header is not sane\n");
 608                 return -EINVAL;
 609         }
 610
 611         /* Read in all elf headers. */
 612         elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
 613         elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
 614         if (!elfcorebuf)
 615                 return -ENOMEM;
 616         addr = elfcorehdr_addr;
 617         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
 618         if (rc < 0) {
 619                 kfree(elfcorebuf);
 620                 return rc;
 621         }
 622
 623         /* Merge all PT_NOTE headers into one. */
 624         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
 625         if (rc) {
 626                 kfree(elfcorebuf);
 627                 return rc;
 628         }
 629         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
 630                                                                 &vmcore_list);
 631         if (rc) {
 632                 kfree(elfcorebuf);
 633                 return rc;
 634         }
 635         set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
 636         return 0;
 637 }
 638
 639 static int __init parse_crash_elf_headers(void)
 640 {
 641         unsigned char e_ident[EI_NIDENT];
 642         u64 addr;
 643         int rc=0;
 644
 645         addr = elfcorehdr_addr;
 646         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
 647         if (rc < 0)
 648                 return rc;
 649         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
 650                 pr_warn("Warning: Core image elf header not found\n");
 651                 return -EINVAL;
 652         }
 653
 654         if (e_ident[EI_CLASS] == ELFCLASS64) {
 655                 rc = parse_crash_elf64_headers();
 656                 if (rc)
 657                         return rc;
 658
 659                 /* Determine vmcore size. */
 660                 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
 661         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
 662                 rc = parse_crash_elf32_headers();
 663                 if (rc)
 664                         return rc;
 665
 666                 /* Determine vmcore size. */
 667                 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
 668         } else {
 669                 pr_warn("Warning: Core image elf header is not sane\n");
 670                 return -EINVAL;
 671         }
 672         return 0;
 673 }
 674
 675 /* Init function for vmcore module. */
 676 static int __init vmcore_init(void)
 677 {
 678         int rc = 0;
 679
 680         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
 681         if (!(is_vmcore_usable()))
 682                 return rc;
 683         rc = parse_crash_elf_headers();
 684         if (rc) {
 685                 pr_warn("Kdump: vmcore not initialized\n");
 686                 return rc;
 687         }
 688
 689         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
 690         if (proc_vmcore)
 691                 proc_vmcore->size = vmcore_size;
 692         return 0;
 693 }
 694 module_init(vmcore_init)
 695
 696 /* Cleanup function for vmcore module. */
 697 void vmcore_cleanup(void)
 698 {
 699         struct list_head *pos, *next;
 700
 701         if (proc_vmcore) {
 702                 proc_remove(proc_vmcore);
 703                 proc_vmcore = NULL;
 704         }
 705
 706         /* clear the vmcore list. */
 707         list_for_each_safe(pos, next, &vmcore_list) {
 708                 struct vmcore *m;
 709
 710                 m = list_entry(pos, struct vmcore, list);
 711                 list_del(&m->list);
 712                 kfree(m);
 713         }
 714         kfree(elfcorebuf);
 715         elfcorebuf = NULL;
 716 }
 717 EXPORT_SYMBOL_GPL(vmcore_cleanup);