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 <linux/vmalloc.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/io.h>
  26 #include "internal.h"
  27
  28 /* List representing chunks of contiguous memory areas and their offsets in
  29  * vmcore file.
  30  */
  31 static LIST_HEAD(vmcore_list);
  32
  33 /* Stores the pointer to the buffer containing kernel elf core headers. */
  34 static char *elfcorebuf;
  35 static size_t elfcorebuf_sz;
  36 static size_t elfcorebuf_sz_orig;
  37
  38 static char *elfnotes_buf;
  39 static size_t elfnotes_sz;
  40
  41 /* Total size of vmcore file. */
  42 static u64 vmcore_size;
  43
  44 static struct proc_dir_entry *proc_vmcore = NULL;
  45
  46 /*
  47  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  48  * The called function has to take care of module refcounting.
  49  */
  50 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
  51
  52 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
  53 {
  54         if (oldmem_pfn_is_ram)
  55                 return -EBUSY;
  56         oldmem_pfn_is_ram = fn;
  57         return 0;
  58 }
  59 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
  60
  61 void unregister_oldmem_pfn_is_ram(void)
  62 {
  63         oldmem_pfn_is_ram = NULL;
  64         wmb();
  65 }
  66 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
  67
  68 static int pfn_is_ram(unsigned long pfn)
  69 {
  70         int (*fn)(unsigned long pfn);
  71         /* pfn is ram unless fn() checks pagetype */
  72         int ret = 1;
  73
  74         /*
  75          * Ask hypervisor if the pfn is really ram.
  76          * A ballooned page contains no data and reading from such a page
  77          * will cause high load in the hypervisor.
  78          */
  79         fn = oldmem_pfn_is_ram;
  80         if (fn)
  81                 ret = fn(pfn);
  82
  83         return ret;
  84 }
  85
  86 /* Reads a page from the oldmem device from given offset. */
  87 static ssize_t read_from_oldmem(char *buf, size_t count,
  88                                 u64 *ppos, int userbuf)
  89 {
  90         unsigned long pfn, offset;
  91         size_t nr_bytes;
  92         ssize_t read = 0, tmp;
  93
  94         if (!count)
  95                 return 0;
  96
  97         offset = (unsigned long)(*ppos % PAGE_SIZE);
  98         pfn = (unsigned long)(*ppos / PAGE_SIZE);
  99
 100         do {
 101                 if (count > (PAGE_SIZE - offset))
 102                         nr_bytes = PAGE_SIZE - offset;
 103                 else
 104                         nr_bytes = count;
 105
 106                 /* If pfn is not ram, return zeros for sparse dump files */
 107                 if (pfn_is_ram(pfn) == 0)
 108                         memset(buf, 0, nr_bytes);
 109                 else {
 110                         tmp = copy_oldmem_page(pfn, buf, nr_bytes,
 111                                                 offset, userbuf);
 112                         if (tmp < 0)
 113                                 return tmp;
 114                 }
 115                 *ppos += nr_bytes;
 116                 count -= nr_bytes;
 117                 buf += nr_bytes;
 118                 read += nr_bytes;
 119                 ++pfn;
 120                 offset = 0;
 121         } while (count);
 122
 123         return read;
 124 }
 125
 126 /* Read from the ELF header and then the crash dump. On error, negative value is
 127  * returned otherwise number of bytes read are returned.
 128  */
 129 static ssize_t read_vmcore(struct file *file, char __user *buffer,
 130                                 size_t buflen, loff_t *fpos)
 131 {
 132         ssize_t acc = 0, tmp;
 133         size_t tsz;
 134         u64 start;
 135         struct vmcore *m = NULL;
 136
 137         if (buflen == 0 || *fpos >= vmcore_size)
 138                 return 0;
 139
 140         /* trim buflen to not go beyond EOF */
 141         if (buflen > vmcore_size - *fpos)
 142                 buflen = vmcore_size - *fpos;
 143
 144         /* Read ELF core header */
 145         if (*fpos < elfcorebuf_sz) {
 146                 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
 147                 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
 148                         return -EFAULT;
 149                 buflen -= tsz;
 150                 *fpos += tsz;
 151                 buffer += tsz;
 152                 acc += tsz;
 153
 154                 /* leave now if filled buffer already */
 155                 if (buflen == 0)
 156                         return acc;
 157         }
 158
 159         /* Read Elf note segment */
 160         if (*fpos < elfcorebuf_sz + elfnotes_sz) {
 161                 void *kaddr;
 162
 163                 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
 164                 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz;
 165                 if (copy_to_user(buffer, kaddr, 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         list_for_each_entry(m, &vmcore_list, list) {
 178                 if (*fpos < m->offset + m->size) {
 179                         tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
 180                         start = m->paddr + *fpos - m->offset;
 181                         tmp = read_from_oldmem(buffer, tsz, &start, 1);
 182                         if (tmp < 0)
 183                                 return tmp;
 184                         buflen -= tsz;
 185                         *fpos += tsz;
 186                         buffer += tsz;
 187                         acc += tsz;
 188
 189                         /* leave now if filled buffer already */
 190                         if (buflen == 0)
 191                                 return acc;
 192                 }
 193         }
 194
 195         return acc;
 196 }
 197
 198 /**
 199  * alloc_elfnotes_buf - allocate buffer for ELF note segment in
 200  *                      vmalloc memory
 201  *
 202  * @notes_sz: size of buffer
 203  *
 204  * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
 205  * the buffer to user-space by means of remap_vmalloc_range().
 206  *
 207  * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
 208  * disabled and there's no need to allow users to mmap the buffer.
 209  */
 210 static inline char *alloc_elfnotes_buf(size_t notes_sz)
 211 {
 212 #ifdef CONFIG_MMU
 213         return vmalloc_user(notes_sz);
 214 #else
 215         return vzalloc(notes_sz);
 216 #endif
 217 }
 218
 219 /*
 220  * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
 221  * essential for mmap_vmcore() in order to map physically
 222  * non-contiguous objects (ELF header, ELF note segment and memory
 223  * regions in the 1st kernel pointed to by PT_LOAD entries) into
 224  * virtually contiguous user-space in ELF layout.
 225  */
 226 #if defined(CONFIG_MMU) && !defined(CONFIG_S390)
 227 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
 228 {
 229         size_t size = vma->vm_end - vma->vm_start;
 230         u64 start, end, len, tsz;
 231         struct vmcore *m;
 232
 233         start = (u64)vma->vm_pgoff << PAGE_SHIFT;
 234         end = start + size;
 235
 236         if (size > vmcore_size || end > vmcore_size)
 237                 return -EINVAL;
 238
 239         if (vma->vm_flags & (VM_WRITE | VM_EXEC))
 240                 return -EPERM;
 241
 242         vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
 243         vma->vm_flags |= VM_MIXEDMAP;
 244
 245         len = 0;
 246
 247         if (start < elfcorebuf_sz) {
 248                 u64 pfn;
 249
 250                 tsz = min(elfcorebuf_sz - (size_t)start, size);
 251                 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
 252                 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
 253                                     vma->vm_page_prot))
 254                         return -EAGAIN;
 255                 size -= tsz;
 256                 start += tsz;
 257                 len += tsz;
 258
 259                 if (size == 0)
 260                         return 0;
 261         }
 262
 263         if (start < elfcorebuf_sz + elfnotes_sz) {
 264                 void *kaddr;
 265
 266                 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
 267                 kaddr = elfnotes_buf + start - elfcorebuf_sz;
 268                 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
 269                                                 kaddr, tsz))
 270                         goto fail;
 271                 size -= tsz;
 272                 start += tsz;
 273                 len += tsz;
 274
 275                 if (size == 0)
 276                         return 0;
 277         }
 278
 279         list_for_each_entry(m, &vmcore_list, list) {
 280                 if (start < m->offset + m->size) {
 281                         u64 paddr = 0;
 282
 283                         tsz = min_t(size_t, m->offset + m->size - start, size);
 284                         paddr = m->paddr + start - m->offset;
 285                         if (remap_pfn_range(vma, vma->vm_start + len,
 286                                             paddr >> PAGE_SHIFT, tsz,
 287                                             vma->vm_page_prot))
 288                                 goto fail;
 289                         size -= tsz;
 290                         start += tsz;
 291                         len += tsz;
 292
 293                         if (size == 0)
 294                                 return 0;
 295                 }
 296         }
 297
 298         return 0;
 299 fail:
 300         do_munmap(vma->vm_mm, vma->vm_start, len);
 301         return -EAGAIN;
 302 }
 303 #else
 304 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
 305 {
 306         return -ENOSYS;
 307 }
 308 #endif
 309
 310 static const struct file_operations proc_vmcore_operations = {
 311         .read           = read_vmcore,
 312         .llseek         = default_llseek,
 313         .mmap           = mmap_vmcore,
 314 };
 315
 316 static struct vmcore* __init get_new_element(void)
 317 {
 318         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
 319 }
 320
 321 static u64 __init get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
 322                                   struct list_head *vc_list)
 323 {
 324         u64 size;
 325         struct vmcore *m;
 326
 327         size = elfsz + elfnotesegsz;
 328         list_for_each_entry(m, vc_list, list) {
 329                 size += m->size;
 330         }
 331         return size;
 332 }
 333
 334 /**
 335  * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
 336  *
 337  * @ehdr_ptr: ELF header
 338  *
 339  * This function updates p_memsz member of each PT_NOTE entry in the
 340  * program header table pointed to by @ehdr_ptr to real size of ELF
 341  * note segment.
 342  */
 343 static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
 344 {
 345         int i, rc=0;
 346         Elf64_Phdr *phdr_ptr;
 347         Elf64_Nhdr *nhdr_ptr;
 348
 349         phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
 350         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 351                 void *notes_section;
 352                 u64 offset, max_sz, sz, real_sz = 0;
 353                 if (phdr_ptr->p_type != PT_NOTE)
 354                         continue;
 355                 max_sz = phdr_ptr->p_memsz;
 356                 offset = phdr_ptr->p_offset;
 357                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 358                 if (!notes_section)
 359                         return -ENOMEM;
 360                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 361                 if (rc < 0) {
 362                         kfree(notes_section);
 363                         return rc;
 364                 }
 365                 nhdr_ptr = notes_section;
 366                 while (real_sz < max_sz) {
 367                         if (nhdr_ptr->n_namesz == 0)
 368                                 break;
 369                         sz = sizeof(Elf64_Nhdr) +
 370                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 371                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 372                         real_sz += sz;
 373                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 374                 }
 375                 kfree(notes_section);
 376                 phdr_ptr->p_memsz = real_sz;
 377         }
 378
 379         return 0;
 380 }
 381
 382 /**
 383  * get_note_number_and_size_elf64 - get the number of PT_NOTE program
 384  * headers and sum of real size of their ELF note segment headers and
 385  * data.
 386  *
 387  * @ehdr_ptr: ELF header
 388  * @nr_ptnote: buffer for the number of PT_NOTE program headers
 389  * @sz_ptnote: buffer for size of unique PT_NOTE program header
 390  *
 391  * This function is used to merge multiple PT_NOTE program headers
 392  * into a unique single one. The resulting unique entry will have
 393  * @sz_ptnote in its phdr->p_mem.
 394  *
 395  * It is assumed that program headers with PT_NOTE type pointed to by
 396  * @ehdr_ptr has already been updated by update_note_header_size_elf64
 397  * and each of PT_NOTE program headers has actual ELF note segment
 398  * size in its p_memsz member.
 399  */
 400 static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
 401                                                  int *nr_ptnote, u64 *sz_ptnote)
 402 {
 403         int i;
 404         Elf64_Phdr *phdr_ptr;
 405
 406         *nr_ptnote = *sz_ptnote = 0;
 407
 408         phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
 409         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 410                 if (phdr_ptr->p_type != PT_NOTE)
 411                         continue;
 412                 *nr_ptnote += 1;
 413                 *sz_ptnote += phdr_ptr->p_memsz;
 414         }
 415
 416         return 0;
 417 }
 418
 419 /**
 420  * copy_notes_elf64 - copy ELF note segments in a given buffer
 421  *
 422  * @ehdr_ptr: ELF header
 423  * @notes_buf: buffer into which ELF note segments are copied
 424  *
 425  * This function is used to copy ELF note segment in the 1st kernel
 426  * into the buffer @notes_buf in the 2nd kernel. It is assumed that
 427  * size of the buffer @notes_buf is equal to or larger than sum of the
 428  * real ELF note segment headers and data.
 429  *
 430  * It is assumed that program headers with PT_NOTE type pointed to by
 431  * @ehdr_ptr has already been updated by update_note_header_size_elf64
 432  * and each of PT_NOTE program headers has actual ELF note segment
 433  * size in its p_memsz member.
 434  */
 435 static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
 436 {
 437         int i, rc=0;
 438         Elf64_Phdr *phdr_ptr;
 439
 440         phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
 441
 442         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 443                 u64 offset;
 444                 if (phdr_ptr->p_type != PT_NOTE)
 445                         continue;
 446                 offset = phdr_ptr->p_offset;
 447                 rc = read_from_oldmem(notes_buf, phdr_ptr->p_memsz, &offset, 0);
 448                 if (rc < 0)
 449                         return rc;
 450                 notes_buf += phdr_ptr->p_memsz;
 451         }
 452
 453         return 0;
 454 }
 455
 456 /* Merges all the PT_NOTE headers into one. */
 457 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 458                                            char **notes_buf, size_t *notes_sz)
 459 {
 460         int i, nr_ptnote=0, rc=0;
 461         char *tmp;
 462         Elf64_Ehdr *ehdr_ptr;
 463         Elf64_Phdr phdr;
 464         u64 phdr_sz = 0, note_off;
 465
 466         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 467
 468         rc = update_note_header_size_elf64(ehdr_ptr);
 469         if (rc < 0)
 470                 return rc;
 471
 472         rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
 473         if (rc < 0)
 474                 return rc;
 475
 476         *notes_sz = roundup(phdr_sz, PAGE_SIZE);
 477         *notes_buf = alloc_elfnotes_buf(*notes_sz);
 478         if (!*notes_buf)
 479                 return -ENOMEM;
 480
 481         rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
 482         if (rc < 0)
 483                 return rc;
 484
 485         /* Prepare merged PT_NOTE program header. */
 486         phdr.p_type    = PT_NOTE;
 487         phdr.p_flags   = 0;
 488         note_off = sizeof(Elf64_Ehdr) +
 489                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 490         phdr.p_offset  = roundup(note_off, PAGE_SIZE);
 491         phdr.p_vaddr   = phdr.p_paddr = 0;
 492         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 493         phdr.p_align   = 0;
 494
 495         /* Add merged PT_NOTE program header*/
 496         tmp = elfptr + sizeof(Elf64_Ehdr);
 497         memcpy(tmp, &phdr, sizeof(phdr));
 498         tmp += sizeof(phdr);
 499
 500         /* Remove unwanted PT_NOTE program headers. */
 501         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 502         *elfsz = *elfsz - i;
 503         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 504         memset(elfptr + *elfsz, 0, i);
 505         *elfsz = roundup(*elfsz, PAGE_SIZE);
 506
 507         /* Modify e_phnum to reflect merged headers. */
 508         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 509
 510         return 0;
 511 }
 512
 513 /**
 514  * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
 515  *
 516  * @ehdr_ptr: ELF header
 517  *
 518  * This function updates p_memsz member of each PT_NOTE entry in the
 519  * program header table pointed to by @ehdr_ptr to real size of ELF
 520  * note segment.
 521  */
 522 static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
 523 {
 524         int i, rc=0;
 525         Elf32_Phdr *phdr_ptr;
 526         Elf32_Nhdr *nhdr_ptr;
 527
 528         phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
 529         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 530                 void *notes_section;
 531                 u64 offset, max_sz, sz, real_sz = 0;
 532                 if (phdr_ptr->p_type != PT_NOTE)
 533                         continue;
 534                 max_sz = phdr_ptr->p_memsz;
 535                 offset = phdr_ptr->p_offset;
 536                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 537                 if (!notes_section)
 538                         return -ENOMEM;
 539                 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
 540                 if (rc < 0) {
 541                         kfree(notes_section);
 542                         return rc;
 543                 }
 544                 nhdr_ptr = notes_section;
 545                 while (real_sz < max_sz) {
 546                         if (nhdr_ptr->n_namesz == 0)
 547                                 break;
 548                         sz = sizeof(Elf32_Nhdr) +
 549                                 ((nhdr_ptr->n_namesz + 3) & ~3) +
 550                                 ((nhdr_ptr->n_descsz + 3) & ~3);
 551                         real_sz += sz;
 552                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 553                 }
 554                 kfree(notes_section);
 555                 phdr_ptr->p_memsz = real_sz;
 556         }
 557
 558         return 0;
 559 }
 560
 561 /**
 562  * get_note_number_and_size_elf32 - get the number of PT_NOTE program
 563  * headers and sum of real size of their ELF note segment headers and
 564  * data.
 565  *
 566  * @ehdr_ptr: ELF header
 567  * @nr_ptnote: buffer for the number of PT_NOTE program headers
 568  * @sz_ptnote: buffer for size of unique PT_NOTE program header
 569  *
 570  * This function is used to merge multiple PT_NOTE program headers
 571  * into a unique single one. The resulting unique entry will have
 572  * @sz_ptnote in its phdr->p_mem.
 573  *
 574  * It is assumed that program headers with PT_NOTE type pointed to by
 575  * @ehdr_ptr has already been updated by update_note_header_size_elf32
 576  * and each of PT_NOTE program headers has actual ELF note segment
 577  * size in its p_memsz member.
 578  */
 579 static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
 580                                                  int *nr_ptnote, u64 *sz_ptnote)
 581 {
 582         int i;
 583         Elf32_Phdr *phdr_ptr;
 584
 585         *nr_ptnote = *sz_ptnote = 0;
 586
 587         phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
 588         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 589                 if (phdr_ptr->p_type != PT_NOTE)
 590                         continue;
 591                 *nr_ptnote += 1;
 592                 *sz_ptnote += phdr_ptr->p_memsz;
 593         }
 594
 595         return 0;
 596 }
 597
 598 /**
 599  * copy_notes_elf32 - copy ELF note segments in a given buffer
 600  *
 601  * @ehdr_ptr: ELF header
 602  * @notes_buf: buffer into which ELF note segments are copied
 603  *
 604  * This function is used to copy ELF note segment in the 1st kernel
 605  * into the buffer @notes_buf in the 2nd kernel. It is assumed that
 606  * size of the buffer @notes_buf is equal to or larger than sum of the
 607  * real ELF note segment headers and data.
 608  *
 609  * It is assumed that program headers with PT_NOTE type pointed to by
 610  * @ehdr_ptr has already been updated by update_note_header_size_elf32
 611  * and each of PT_NOTE program headers has actual ELF note segment
 612  * size in its p_memsz member.
 613  */
 614 static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
 615 {
 616         int i, rc=0;
 617         Elf32_Phdr *phdr_ptr;
 618
 619         phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
 620
 621         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 622                 u64 offset;
 623                 if (phdr_ptr->p_type != PT_NOTE)
 624                         continue;
 625                 offset = phdr_ptr->p_offset;
 626                 rc = read_from_oldmem(notes_buf, phdr_ptr->p_memsz, &offset, 0);
 627                 if (rc < 0)
 628                         return rc;
 629                 notes_buf += phdr_ptr->p_memsz;
 630         }
 631
 632         return 0;
 633 }
 634
 635 /* Merges all the PT_NOTE headers into one. */
 636 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 637                                            char **notes_buf, size_t *notes_sz)
 638 {
 639         int i, nr_ptnote=0, rc=0;
 640         char *tmp;
 641         Elf32_Ehdr *ehdr_ptr;
 642         Elf32_Phdr phdr;
 643         u64 phdr_sz = 0, note_off;
 644
 645         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 646
 647         rc = update_note_header_size_elf32(ehdr_ptr);
 648         if (rc < 0)
 649                 return rc;
 650
 651         rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
 652         if (rc < 0)
 653                 return rc;
 654
 655         *notes_sz = roundup(phdr_sz, PAGE_SIZE);
 656         *notes_buf = alloc_elfnotes_buf(*notes_sz);
 657         if (!*notes_buf)
 658                 return -ENOMEM;
 659
 660         rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
 661         if (rc < 0)
 662                 return rc;
 663
 664         /* Prepare merged PT_NOTE program header. */
 665         phdr.p_type    = PT_NOTE;
 666         phdr.p_flags   = 0;
 667         note_off = sizeof(Elf32_Ehdr) +
 668                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
 669         phdr.p_offset  = roundup(note_off, PAGE_SIZE);
 670         phdr.p_vaddr   = phdr.p_paddr = 0;
 671         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 672         phdr.p_align   = 0;
 673
 674         /* Add merged PT_NOTE program header*/
 675         tmp = elfptr + sizeof(Elf32_Ehdr);
 676         memcpy(tmp, &phdr, sizeof(phdr));
 677         tmp += sizeof(phdr);
 678
 679         /* Remove unwanted PT_NOTE program headers. */
 680         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
 681         *elfsz = *elfsz - i;
 682         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
 683         memset(elfptr + *elfsz, 0, i);
 684         *elfsz = roundup(*elfsz, PAGE_SIZE);
 685
 686         /* Modify e_phnum to reflect merged headers. */
 687         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 688
 689         return 0;
 690 }
 691
 692 /* Add memory chunks represented by program headers to vmcore list. Also update
 693  * the new offset fields of exported program headers. */
 694 static int __init process_ptload_program_headers_elf64(char *elfptr,
 695                                                 size_t elfsz,
 696                                                 size_t elfnotes_sz,
 697                                                 struct list_head *vc_list)
 698 {
 699         int i;
 700         Elf64_Ehdr *ehdr_ptr;
 701         Elf64_Phdr *phdr_ptr;
 702         loff_t vmcore_off;
 703         struct vmcore *new;
 704
 705         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 706         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 707
 708         /* Skip Elf header, program headers and Elf note segment. */
 709         vmcore_off = elfsz + elfnotes_sz;
 710
 711         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 712                 u64 paddr, start, end, size;
 713
 714                 if (phdr_ptr->p_type != PT_LOAD)
 715                         continue;
 716
 717                 paddr = phdr_ptr->p_offset;
 718                 start = rounddown(paddr, PAGE_SIZE);
 719                 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
 720                 size = end - start;
 721
 722                 /* Add this contiguous chunk of memory to vmcore list.*/
 723                 new = get_new_element();
 724                 if (!new)
 725                         return -ENOMEM;
 726                 new->paddr = start;
 727                 new->size = size;
 728                 list_add_tail(&new->list, vc_list);
 729
 730                 /* Update the program header offset. */
 731                 phdr_ptr->p_offset = vmcore_off + (paddr - start);
 732                 vmcore_off = vmcore_off + size;
 733         }
 734         return 0;
 735 }
 736
 737 static int __init process_ptload_program_headers_elf32(char *elfptr,
 738                                                 size_t elfsz,
 739                                                 size_t elfnotes_sz,
 740                                                 struct list_head *vc_list)
 741 {
 742         int i;
 743         Elf32_Ehdr *ehdr_ptr;
 744         Elf32_Phdr *phdr_ptr;
 745         loff_t vmcore_off;
 746         struct vmcore *new;
 747
 748         ehdr_ptr = (Elf32_Ehdr *)elfptr;
 749         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
 750
 751         /* Skip Elf header, program headers and Elf note segment. */
 752         vmcore_off = elfsz + elfnotes_sz;
 753
 754         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 755                 u64 paddr, start, end, size;
 756
 757                 if (phdr_ptr->p_type != PT_LOAD)
 758                         continue;
 759
 760                 paddr = phdr_ptr->p_offset;
 761                 start = rounddown(paddr, PAGE_SIZE);
 762                 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
 763                 size = end - start;
 764
 765                 /* Add this contiguous chunk of memory to vmcore list.*/
 766                 new = get_new_element();
 767                 if (!new)
 768                         return -ENOMEM;
 769                 new->paddr = start;
 770                 new->size = size;
 771                 list_add_tail(&new->list, vc_list);
 772
 773                 /* Update the program header offset */
 774                 phdr_ptr->p_offset = vmcore_off + (paddr - start);
 775                 vmcore_off = vmcore_off + size;
 776         }
 777         return 0;
 778 }
 779
 780 /* Sets offset fields of vmcore elements. */
 781 static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
 782                                            struct list_head *vc_list)
 783 {
 784         loff_t vmcore_off;
 785         struct vmcore *m;
 786
 787         /* Skip Elf header, program headers and Elf note segment. */
 788         vmcore_off = elfsz + elfnotes_sz;
 789
 790         list_for_each_entry(m, vc_list, list) {
 791                 m->offset = vmcore_off;
 792                 vmcore_off += m->size;
 793         }
 794 }
 795
 796 static void free_elfcorebuf(void)
 797 {
 798         free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
 799         elfcorebuf = NULL;
 800         vfree(elfnotes_buf);
 801         elfnotes_buf = NULL;
 802 }
 803
 804 static int __init parse_crash_elf64_headers(void)
 805 {
 806         int rc=0;
 807         Elf64_Ehdr ehdr;
 808         u64 addr;
 809
 810         addr = elfcorehdr_addr;
 811
 812         /* Read Elf header */
 813         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
 814         if (rc < 0)
 815                 return rc;
 816
 817         /* Do some basic Verification. */
 818         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 819                 (ehdr.e_type != ET_CORE) ||
 820                 !vmcore_elf64_check_arch(&ehdr) ||
 821                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
 822                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 823                 ehdr.e_version != EV_CURRENT ||
 824                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
 825                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
 826                 ehdr.e_phnum == 0) {
 827                 pr_warn("Warning: Core image elf header is not sane\n");
 828                 return -EINVAL;
 829         }
 830
 831         /* Read in all elf headers. */
 832         elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
 833                                 ehdr.e_phnum * sizeof(Elf64_Phdr);
 834         elfcorebuf_sz = elfcorebuf_sz_orig;
 835         elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 836                                               get_order(elfcorebuf_sz_orig));
 837         if (!elfcorebuf)
 838                 return -ENOMEM;
 839         addr = elfcorehdr_addr;
 840         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0);
 841         if (rc < 0)
 842                 goto fail;
 843
 844         /* Merge all PT_NOTE headers into one. */
 845         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
 846                                       &elfnotes_buf, &elfnotes_sz);
 847         if (rc)
 848                 goto fail;
 849         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
 850                                                   elfnotes_sz, &vmcore_list);
 851         if (rc)
 852                 goto fail;
 853         set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
 854         return 0;
 855 fail:
 856         free_elfcorebuf();
 857         return rc;
 858 }
 859
 860 static int __init parse_crash_elf32_headers(void)
 861 {
 862         int rc=0;
 863         Elf32_Ehdr ehdr;
 864         u64 addr;
 865
 866         addr = elfcorehdr_addr;
 867
 868         /* Read Elf header */
 869         rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
 870         if (rc < 0)
 871                 return rc;
 872
 873         /* Do some basic Verification. */
 874         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 875                 (ehdr.e_type != ET_CORE) ||
 876                 !elf_check_arch(&ehdr) ||
 877                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
 878                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
 879                 ehdr.e_version != EV_CURRENT ||
 880                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
 881                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
 882                 ehdr.e_phnum == 0) {
 883                 pr_warn("Warning: Core image elf header is not sane\n");
 884                 return -EINVAL;
 885         }
 886
 887         /* Read in all elf headers. */
 888         elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
 889         elfcorebuf_sz = elfcorebuf_sz_orig;
 890         elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 891                                               get_order(elfcorebuf_sz_orig));
 892         if (!elfcorebuf)
 893                 return -ENOMEM;
 894         addr = elfcorehdr_addr;
 895         rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0);
 896         if (rc < 0)
 897                 goto fail;
 898
 899         /* Merge all PT_NOTE headers into one. */
 900         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
 901                                       &elfnotes_buf, &elfnotes_sz);
 902         if (rc)
 903                 goto fail;
 904         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
 905                                                   elfnotes_sz, &vmcore_list);
 906         if (rc)
 907                 goto fail;
 908         set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
 909         return 0;
 910 fail:
 911         free_elfcorebuf();
 912         return rc;
 913 }
 914
 915 static int __init parse_crash_elf_headers(void)
 916 {
 917         unsigned char e_ident[EI_NIDENT];
 918         u64 addr;
 919         int rc=0;
 920
 921         addr = elfcorehdr_addr;
 922         rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
 923         if (rc < 0)
 924                 return rc;
 925         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
 926                 pr_warn("Warning: Core image elf header not found\n");
 927                 return -EINVAL;
 928         }
 929
 930         if (e_ident[EI_CLASS] == ELFCLASS64) {
 931                 rc = parse_crash_elf64_headers();
 932                 if (rc)
 933                         return rc;
 934         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
 935                 rc = parse_crash_elf32_headers();
 936                 if (rc)
 937                         return rc;
 938         } else {
 939                 pr_warn("Warning: Core image elf header is not sane\n");
 940                 return -EINVAL;
 941         }
 942
 943         /* Determine vmcore size. */
 944         vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
 945                                       &vmcore_list);
 946
 947         return 0;
 948 }
 949
 950 /* Init function for vmcore module. */
 951 static int __init vmcore_init(void)
 952 {
 953         int rc = 0;
 954
 955         /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
 956         if (!(is_vmcore_usable()))
 957                 return rc;
 958         rc = parse_crash_elf_headers();
 959         if (rc) {
 960                 pr_warn("Kdump: vmcore not initialized\n");
 961                 return rc;
 962         }
 963
 964         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
 965         if (proc_vmcore)
 966                 proc_vmcore->size = vmcore_size;
 967         return 0;
 968 }
 969 module_init(vmcore_init)
 970
 971 /* Cleanup function for vmcore module. */
 972 void vmcore_cleanup(void)
 973 {
 974         struct list_head *pos, *next;
 975
 976         if (proc_vmcore) {
 977                 proc_remove(proc_vmcore);
 978                 proc_vmcore = NULL;
 979         }
 980
 981         /* clear the vmcore list. */
 982         list_for_each_safe(pos, next, &vmcore_list) {
 983                 struct vmcore *m;
 984
 985                 m = list_entry(pos, struct vmcore, list);
 986                 list_del(&m->list);
 987                 kfree(m);
 988         }
 989         free_elfcorebuf();
 990 }
 991 EXPORT_SYMBOL_GPL(vmcore_cleanup);