fs/proc/vmcore.c

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This source file includes following definitions.
register_oldmem_pfn_is_ram
unregister_oldmem_pfn_is_ram
pfn_is_ram
read_from_oldmem
elfcorehdr_alloc
elfcorehdr_free
elfcorehdr_read
elfcorehdr_read_notes
remap_oldmem_pfn_range
copy_oldmem_page_encrypted
copy_to
vmcoredd_copy_dumps
vmcoredd_mmap_dumps
__read_vmcore
read_vmcore
mmap_vmcore_fault
vmcore_alloc_buf
remap_oldmem_pfn_checked
vmcore_remap_oldmem_pfn
mmap_vmcore
mmap_vmcore
get_new_element
get_vmcore_size
update_note_header_size_elf64
get_note_number_and_size_elf64
copy_notes_elf64
merge_note_headers_elf64
update_note_header_size_elf32
get_note_number_and_size_elf32
copy_notes_elf32
merge_note_headers_elf32
process_ptload_program_headers_elf64
process_ptload_program_headers_elf32
set_vmcore_list_offsets
free_elfcorebuf
parse_crash_elf64_headers
parse_crash_elf32_headers
parse_crash_elf_headers
vmcoredd_write_header
vmcoredd_update_program_headers
vmcoredd_update_size
vmcore_add_device_dump
vmcore_free_device_dumps
vmcore_init
vmcore_cleanup
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *      fs/proc/vmcore.c Interface for accessing the crash
   4  *                               dump from the system's previous life.
   5  *      Heavily borrowed from fs/proc/kcore.c
   6  *      Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
   7  *      Copyright (C) IBM Corporation, 2004. All rights reserved
   8  *
   9  */
  10 
  11 #include <linux/mm.h>
  12 #include <linux/kcore.h>
  13 #include <linux/user.h>
  14 #include <linux/elf.h>
  15 #include <linux/elfcore.h>
  16 #include <linux/export.h>
  17 #include <linux/slab.h>
  18 #include <linux/highmem.h>
  19 #include <linux/printk.h>
  20 #include <linux/memblock.h>
  21 #include <linux/init.h>
  22 #include <linux/crash_dump.h>
  23 #include <linux/list.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/mutex.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/pagemap.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/mem_encrypt.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/io.h>
  32 #include "internal.h"
  33 
  34 /* List representing chunks of contiguous memory areas and their offsets in
  35  * vmcore file.
  36  */
  37 static LIST_HEAD(vmcore_list);
  38 
  39 /* Stores the pointer to the buffer containing kernel elf core headers. */
  40 static char *elfcorebuf;
  41 static size_t elfcorebuf_sz;
  42 static size_t elfcorebuf_sz_orig;
  43 
  44 static char *elfnotes_buf;
  45 static size_t elfnotes_sz;
  46 /* Size of all notes minus the device dump notes */
  47 static size_t elfnotes_orig_sz;
  48 
  49 /* Total size of vmcore file. */
  50 static u64 vmcore_size;
  51 
  52 static struct proc_dir_entry *proc_vmcore;
  53 
  54 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
  55 /* Device Dump list and mutex to synchronize access to list */
  56 static LIST_HEAD(vmcoredd_list);
  57 static DEFINE_MUTEX(vmcoredd_mutex);
  58 
  59 static bool vmcoredd_disabled;
  60 core_param(novmcoredd, vmcoredd_disabled, bool, 0);
  61 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
  62 
  63 /* Device Dump Size */
  64 static size_t vmcoredd_orig_sz;
  65 
  66 /*
  67  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  68  * The called function has to take care of module refcounting.
  69  */
  70 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
  71 
  72 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
  73 {
  74         if (oldmem_pfn_is_ram)
  75                 return -EBUSY;
  76         oldmem_pfn_is_ram = fn;
  77         return 0;
  78 }
  79 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
  80 
  81 void unregister_oldmem_pfn_is_ram(void)
  82 {
  83         oldmem_pfn_is_ram = NULL;
  84         wmb();
  85 }
  86 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
  87 
  88 static int pfn_is_ram(unsigned long pfn)
  89 {
  90         int (*fn)(unsigned long pfn);
  91         /* pfn is ram unless fn() checks pagetype */
  92         int ret = 1;
  93 
  94         /*
  95          * Ask hypervisor if the pfn is really ram.
  96          * A ballooned page contains no data and reading from such a page
  97          * will cause high load in the hypervisor.
  98          */
  99         fn = oldmem_pfn_is_ram;
 100         if (fn)
 101                 ret = fn(pfn);
 102 
 103         return ret;
 104 }
 105 
 106 /* Reads a page from the oldmem device from given offset. */
 107 ssize_t read_from_oldmem(char *buf, size_t count,
 108                          u64 *ppos, int userbuf,
 109                          bool encrypted)
 110 {
 111         unsigned long pfn, offset;
 112         size_t nr_bytes;
 113         ssize_t read = 0, tmp;
 114 
 115         if (!count)
 116                 return 0;
 117 
 118         offset = (unsigned long)(*ppos % PAGE_SIZE);
 119         pfn = (unsigned long)(*ppos / PAGE_SIZE);
 120 
 121         do {
 122                 if (count > (PAGE_SIZE - offset))
 123                         nr_bytes = PAGE_SIZE - offset;
 124                 else
 125                         nr_bytes = count;
 126 
 127                 /* If pfn is not ram, return zeros for sparse dump files */
 128                 if (pfn_is_ram(pfn) == 0)
 129                         memset(buf, 0, nr_bytes);
 130                 else {
 131                         if (encrypted)
 132                                 tmp = copy_oldmem_page_encrypted(pfn, buf,
 133                                                                  nr_bytes,
 134                                                                  offset,
 135                                                                  userbuf);
 136                         else
 137                                 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
 138                                                        offset, userbuf);
 139 
 140                         if (tmp < 0)
 141                                 return tmp;
 142                 }
 143                 *ppos += nr_bytes;
 144                 count -= nr_bytes;
 145                 buf += nr_bytes;
 146                 read += nr_bytes;
 147                 ++pfn;
 148                 offset = 0;
 149         } while (count);
 150 
 151         return read;
 152 }
 153 
 154 /*
 155  * Architectures may override this function to allocate ELF header in 2nd kernel
 156  */
 157 int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
 158 {
 159         return 0;
 160 }
 161 
 162 /*
 163  * Architectures may override this function to free header
 164  */
 165 void __weak elfcorehdr_free(unsigned long long addr)
 166 {}
 167 
 168 /*
 169  * Architectures may override this function to read from ELF header
 170  */
 171 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 172 {
 173         return read_from_oldmem(buf, count, ppos, 0, false);
 174 }
 175 
 176 /*
 177  * Architectures may override this function to read from notes sections
 178  */
 179 ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
 180 {
 181         return read_from_oldmem(buf, count, ppos, 0, mem_encrypt_active());
 182 }
 183 
 184 /*
 185  * Architectures may override this function to map oldmem
 186  */
 187 int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
 188                                   unsigned long from, unsigned long pfn,
 189                                   unsigned long size, pgprot_t prot)
 190 {
 191         prot = pgprot_encrypted(prot);
 192         return remap_pfn_range(vma, from, pfn, size, prot);
 193 }
 194 
 195 /*
 196  * Architectures which support memory encryption override this.
 197  */
 198 ssize_t __weak
 199 copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
 200                            unsigned long offset, int userbuf)
 201 {
 202         return copy_oldmem_page(pfn, buf, csize, offset, userbuf);
 203 }
 204 
 205 /*
 206  * Copy to either kernel or user space
 207  */
 208 static int copy_to(void *target, void *src, size_t size, int userbuf)
 209 {
 210         if (userbuf) {
 211                 if (copy_to_user((char __user *) target, src, size))
 212                         return -EFAULT;
 213         } else {
 214                 memcpy(target, src, size);
 215         }
 216         return 0;
 217 }
 218 
 219 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
 220 static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
 221 {
 222         struct vmcoredd_node *dump;
 223         u64 offset = 0;
 224         int ret = 0;
 225         size_t tsz;
 226         char *buf;
 227 
 228         mutex_lock(&vmcoredd_mutex);
 229         list_for_each_entry(dump, &vmcoredd_list, list) {
 230                 if (start < offset + dump->size) {
 231                         tsz = min(offset + (u64)dump->size - start, (u64)size);
 232                         buf = dump->buf + start - offset;
 233                         if (copy_to(dst, buf, tsz, userbuf)) {
 234                                 ret = -EFAULT;
 235                                 goto out_unlock;
 236                         }
 237 
 238                         size -= tsz;
 239                         start += tsz;
 240                         dst += tsz;
 241 
 242                         /* Leave now if buffer filled already */
 243                         if (!size)
 244                                 goto out_unlock;
 245                 }
 246                 offset += dump->size;
 247         }
 248 
 249 out_unlock:
 250         mutex_unlock(&vmcoredd_mutex);
 251         return ret;
 252 }
 253 
 254 #ifdef CONFIG_MMU
 255 static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
 256                                u64 start, size_t size)
 257 {
 258         struct vmcoredd_node *dump;
 259         u64 offset = 0;
 260         int ret = 0;
 261         size_t tsz;
 262         char *buf;
 263 
 264         mutex_lock(&vmcoredd_mutex);
 265         list_for_each_entry(dump, &vmcoredd_list, list) {
 266                 if (start < offset + dump->size) {
 267                         tsz = min(offset + (u64)dump->size - start, (u64)size);
 268                         buf = dump->buf + start - offset;
 269                         if (remap_vmalloc_range_partial(vma, dst, buf, 0,
 270                                                         tsz)) {
 271                                 ret = -EFAULT;
 272                                 goto out_unlock;
 273                         }
 274 
 275                         size -= tsz;
 276                         start += tsz;
 277                         dst += tsz;
 278 
 279                         /* Leave now if buffer filled already */
 280                         if (!size)
 281                                 goto out_unlock;
 282                 }
 283                 offset += dump->size;
 284         }
 285 
 286 out_unlock:
 287         mutex_unlock(&vmcoredd_mutex);
 288         return ret;
 289 }
 290 #endif /* CONFIG_MMU */
 291 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
 292 
 293 /* Read from the ELF header and then the crash dump. On error, negative value is
 294  * returned otherwise number of bytes read are returned.
 295  */
 296 static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
 297                              int userbuf)
 298 {
 299         ssize_t acc = 0, tmp;
 300         size_t tsz;
 301         u64 start;
 302         struct vmcore *m = NULL;
 303 
 304         if (buflen == 0 || *fpos >= vmcore_size)
 305                 return 0;
 306 
 307         /* trim buflen to not go beyond EOF */
 308         if (buflen > vmcore_size - *fpos)
 309                 buflen = vmcore_size - *fpos;
 310 
 311         /* Read ELF core header */
 312         if (*fpos < elfcorebuf_sz) {
 313                 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
 314                 if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
 315                         return -EFAULT;
 316                 buflen -= tsz;
 317                 *fpos += tsz;
 318                 buffer += tsz;
 319                 acc += tsz;
 320 
 321                 /* leave now if filled buffer already */
 322                 if (buflen == 0)
 323                         return acc;
 324         }
 325 
 326         /* Read Elf note segment */
 327         if (*fpos < elfcorebuf_sz + elfnotes_sz) {
 328                 void *kaddr;
 329 
 330                 /* We add device dumps before other elf notes because the
 331                  * other elf notes may not fill the elf notes buffer
 332                  * completely and we will end up with zero-filled data
 333                  * between the elf notes and the device dumps. Tools will
 334                  * then try to decode this zero-filled data as valid notes
 335                  * and we don't want that. Hence, adding device dumps before
 336                  * the other elf notes ensure that zero-filled data can be
 337                  * avoided.
 338                  */
 339 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
 340                 /* Read device dumps */
 341                 if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
 342                         tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
 343                                   (size_t)*fpos, buflen);
 344                         start = *fpos - elfcorebuf_sz;
 345                         if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf))
 346                                 return -EFAULT;
 347 
 348                         buflen -= tsz;
 349                         *fpos += tsz;
 350                         buffer += tsz;
 351                         acc += tsz;
 352 
 353                         /* leave now if filled buffer already */
 354                         if (!buflen)
 355                                 return acc;
 356                 }
 357 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
 358 
 359                 /* Read remaining elf notes */
 360                 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
 361                 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
 362                 if (copy_to(buffer, kaddr, tsz, userbuf))
 363                         return -EFAULT;
 364 
 365                 buflen -= tsz;
 366                 *fpos += tsz;
 367                 buffer += tsz;
 368                 acc += tsz;
 369 
 370                 /* leave now if filled buffer already */
 371                 if (buflen == 0)
 372                         return acc;
 373         }
 374 
 375         list_for_each_entry(m, &vmcore_list, list) {
 376                 if (*fpos < m->offset + m->size) {
 377                         tsz = (size_t)min_t(unsigned long long,
 378                                             m->offset + m->size - *fpos,
 379                                             buflen);
 380                         start = m->paddr + *fpos - m->offset;
 381                         tmp = read_from_oldmem(buffer, tsz, &start,
 382                                                userbuf, mem_encrypt_active());
 383                         if (tmp < 0)
 384                                 return tmp;
 385                         buflen -= tsz;
 386                         *fpos += tsz;
 387                         buffer += tsz;
 388                         acc += tsz;
 389 
 390                         /* leave now if filled buffer already */
 391                         if (buflen == 0)
 392                                 return acc;
 393                 }
 394         }
 395 
 396         return acc;
 397 }
 398 
 399 static ssize_t read_vmcore(struct file *file, char __user *buffer,
 400                            size_t buflen, loff_t *fpos)
 401 {
 402         return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
 403 }
 404 
 405 /*
 406  * The vmcore fault handler uses the page cache and fills data using the
 407  * standard __vmcore_read() function.
 408  *
 409  * On s390 the fault handler is used for memory regions that can't be mapped
 410  * directly with remap_pfn_range().
 411  */
 412 static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
 413 {
 414 #ifdef CONFIG_S390
 415         struct address_space *mapping = vmf->vma->vm_file->f_mapping;
 416         pgoff_t index = vmf->pgoff;
 417         struct page *page;
 418         loff_t offset;
 419         char *buf;
 420         int rc;
 421 
 422         page = find_or_create_page(mapping, index, GFP_KERNEL);
 423         if (!page)
 424                 return VM_FAULT_OOM;
 425         if (!PageUptodate(page)) {
 426                 offset = (loff_t) index << PAGE_SHIFT;
 427                 buf = __va((page_to_pfn(page) << PAGE_SHIFT));
 428                 rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
 429                 if (rc < 0) {
 430                         unlock_page(page);
 431                         put_page(page);
 432                         return vmf_error(rc);
 433                 }
 434                 SetPageUptodate(page);
 435         }
 436         unlock_page(page);
 437         vmf->page = page;
 438         return 0;
 439 #else
 440         return VM_FAULT_SIGBUS;
 441 #endif
 442 }
 443 
 444 static const struct vm_operations_struct vmcore_mmap_ops = {
 445         .fault = mmap_vmcore_fault,
 446 };
 447 
 448 /**
 449  * vmcore_alloc_buf - allocate buffer in vmalloc memory
 450  * @sizez: size of buffer
 451  *
 452  * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
 453  * the buffer to user-space by means of remap_vmalloc_range().
 454  *
 455  * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
 456  * disabled and there's no need to allow users to mmap the buffer.
 457  */
 458 static inline char *vmcore_alloc_buf(size_t size)
 459 {
 460 #ifdef CONFIG_MMU
 461         return vmalloc_user(size);
 462 #else
 463         return vzalloc(size);
 464 #endif
 465 }
 466 
 467 /*
 468  * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
 469  * essential for mmap_vmcore() in order to map physically
 470  * non-contiguous objects (ELF header, ELF note segment and memory
 471  * regions in the 1st kernel pointed to by PT_LOAD entries) into
 472  * virtually contiguous user-space in ELF layout.
 473  */
 474 #ifdef CONFIG_MMU
 475 /*
 476  * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
 477  * reported as not being ram with the zero page.
 478  *
 479  * @vma: vm_area_struct describing requested mapping
 480  * @from: start remapping from
 481  * @pfn: page frame number to start remapping to
 482  * @size: remapping size
 483  * @prot: protection bits
 484  *
 485  * Returns zero on success, -EAGAIN on failure.
 486  */
 487 static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
 488                                     unsigned long from, unsigned long pfn,
 489                                     unsigned long size, pgprot_t prot)
 490 {
 491         unsigned long map_size;
 492         unsigned long pos_start, pos_end, pos;
 493         unsigned long zeropage_pfn = my_zero_pfn(0);
 494         size_t len = 0;
 495 
 496         pos_start = pfn;
 497         pos_end = pfn + (size >> PAGE_SHIFT);
 498 
 499         for (pos = pos_start; pos < pos_end; ++pos) {
 500                 if (!pfn_is_ram(pos)) {
 501                         /*
 502                          * We hit a page which is not ram. Remap the continuous
 503                          * region between pos_start and pos-1 and replace
 504                          * the non-ram page at pos with the zero page.
 505                          */
 506                         if (pos > pos_start) {
 507                                 /* Remap continuous region */
 508                                 map_size = (pos - pos_start) << PAGE_SHIFT;
 509                                 if (remap_oldmem_pfn_range(vma, from + len,
 510                                                            pos_start, map_size,
 511                                                            prot))
 512                                         goto fail;
 513                                 len += map_size;
 514                         }
 515                         /* Remap the zero page */
 516                         if (remap_oldmem_pfn_range(vma, from + len,
 517                                                    zeropage_pfn,
 518                                                    PAGE_SIZE, prot))
 519                                 goto fail;
 520                         len += PAGE_SIZE;
 521                         pos_start = pos + 1;
 522                 }
 523         }
 524         if (pos > pos_start) {
 525                 /* Remap the rest */
 526                 map_size = (pos - pos_start) << PAGE_SHIFT;
 527                 if (remap_oldmem_pfn_range(vma, from + len, pos_start,
 528                                            map_size, prot))
 529                         goto fail;
 530         }
 531         return 0;
 532 fail:
 533         do_munmap(vma->vm_mm, from, len, NULL);
 534         return -EAGAIN;
 535 }
 536 
 537 static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
 538                             unsigned long from, unsigned long pfn,
 539                             unsigned long size, pgprot_t prot)
 540 {
 541         /*
 542          * Check if oldmem_pfn_is_ram was registered to avoid
 543          * looping over all pages without a reason.
 544          */
 545         if (oldmem_pfn_is_ram)
 546                 return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
 547         else
 548                 return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
 549 }
 550 
 551 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
 552 {
 553         size_t size = vma->vm_end - vma->vm_start;
 554         u64 start, end, len, tsz;
 555         struct vmcore *m;
 556 
 557         start = (u64)vma->vm_pgoff << PAGE_SHIFT;
 558         end = start + size;
 559 
 560         if (size > vmcore_size || end > vmcore_size)
 561                 return -EINVAL;
 562 
 563         if (vma->vm_flags & (VM_WRITE | VM_EXEC))
 564                 return -EPERM;
 565 
 566         vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
 567         vma->vm_flags |= VM_MIXEDMAP;
 568         vma->vm_ops = &vmcore_mmap_ops;
 569 
 570         len = 0;
 571 
 572         if (start < elfcorebuf_sz) {
 573                 u64 pfn;
 574 
 575                 tsz = min(elfcorebuf_sz - (size_t)start, size);
 576                 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
 577                 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
 578                                     vma->vm_page_prot))
 579                         return -EAGAIN;
 580                 size -= tsz;
 581                 start += tsz;
 582                 len += tsz;
 583 
 584                 if (size == 0)
 585                         return 0;
 586         }
 587 
 588         if (start < elfcorebuf_sz + elfnotes_sz) {
 589                 void *kaddr;
 590 
 591                 /* We add device dumps before other elf notes because the
 592                  * other elf notes may not fill the elf notes buffer
 593                  * completely and we will end up with zero-filled data
 594                  * between the elf notes and the device dumps. Tools will
 595                  * then try to decode this zero-filled data as valid notes
 596                  * and we don't want that. Hence, adding device dumps before
 597                  * the other elf notes ensure that zero-filled data can be
 598                  * avoided. This also ensures that the device dumps and
 599                  * other elf notes can be properly mmaped at page aligned
 600                  * address.
 601                  */
 602 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
 603                 /* Read device dumps */
 604                 if (start < elfcorebuf_sz + vmcoredd_orig_sz) {
 605                         u64 start_off;
 606 
 607                         tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
 608                                   (size_t)start, size);
 609                         start_off = start - elfcorebuf_sz;
 610                         if (vmcoredd_mmap_dumps(vma, vma->vm_start + len,
 611                                                 start_off, tsz))
 612                                 goto fail;
 613 
 614                         size -= tsz;
 615                         start += tsz;
 616                         len += tsz;
 617 
 618                         /* leave now if filled buffer already */
 619                         if (!size)
 620                                 return 0;
 621                 }
 622 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
 623 
 624                 /* Read remaining elf notes */
 625                 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
 626                 kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_sz;
 627                 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
 628                                                 kaddr, 0, tsz))
 629                         goto fail;
 630 
 631                 size -= tsz;
 632                 start += tsz;
 633                 len += tsz;
 634 
 635                 if (size == 0)
 636                         return 0;
 637         }
 638 
 639         list_for_each_entry(m, &vmcore_list, list) {
 640                 if (start < m->offset + m->size) {
 641                         u64 paddr = 0;
 642 
 643                         tsz = (size_t)min_t(unsigned long long,
 644                                             m->offset + m->size - start, size);
 645                         paddr = m->paddr + start - m->offset;
 646                         if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
 647                                                     paddr >> PAGE_SHIFT, tsz,
 648                                                     vma->vm_page_prot))
 649                                 goto fail;
 650                         size -= tsz;
 651                         start += tsz;
 652                         len += tsz;
 653 
 654                         if (size == 0)
 655                                 return 0;
 656                 }
 657         }
 658 
 659         return 0;
 660 fail:
 661         do_munmap(vma->vm_mm, vma->vm_start, len, NULL);
 662         return -EAGAIN;
 663 }
 664 #else
 665 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
 666 {
 667         return -ENOSYS;
 668 }
 669 #endif
 670 
 671 static const struct file_operations proc_vmcore_operations = {
 672         .read           = read_vmcore,
 673         .llseek         = default_llseek,
 674         .mmap           = mmap_vmcore,
 675 };
 676 
 677 static struct vmcore* __init get_new_element(void)
 678 {
 679         return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
 680 }
 681 
 682 static u64 get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
 683                            struct list_head *vc_list)
 684 {
 685         u64 size;
 686         struct vmcore *m;
 687 
 688         size = elfsz + elfnotesegsz;
 689         list_for_each_entry(m, vc_list, list) {
 690                 size += m->size;
 691         }
 692         return size;
 693 }
 694 
 695 /**
 696  * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
 697  *
 698  * @ehdr_ptr: ELF header
 699  *
 700  * This function updates p_memsz member of each PT_NOTE entry in the
 701  * program header table pointed to by @ehdr_ptr to real size of ELF
 702  * note segment.
 703  */
 704 static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
 705 {
 706         int i, rc=0;
 707         Elf64_Phdr *phdr_ptr;
 708         Elf64_Nhdr *nhdr_ptr;
 709 
 710         phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
 711         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 712                 void *notes_section;
 713                 u64 offset, max_sz, sz, real_sz = 0;
 714                 if (phdr_ptr->p_type != PT_NOTE)
 715                         continue;
 716                 max_sz = phdr_ptr->p_memsz;
 717                 offset = phdr_ptr->p_offset;
 718                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 719                 if (!notes_section)
 720                         return -ENOMEM;
 721                 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
 722                 if (rc < 0) {
 723                         kfree(notes_section);
 724                         return rc;
 725                 }
 726                 nhdr_ptr = notes_section;
 727                 while (nhdr_ptr->n_namesz != 0) {
 728                         sz = sizeof(Elf64_Nhdr) +
 729                                 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
 730                                 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
 731                         if ((real_sz + sz) > max_sz) {
 732                                 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
 733                                         nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
 734                                 break;
 735                         }
 736                         real_sz += sz;
 737                         nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 738                 }
 739                 kfree(notes_section);
 740                 phdr_ptr->p_memsz = real_sz;
 741                 if (real_sz == 0) {
 742                         pr_warn("Warning: Zero PT_NOTE entries found\n");
 743                 }
 744         }
 745 
 746         return 0;
 747 }
 748 
 749 /**
 750  * get_note_number_and_size_elf64 - get the number of PT_NOTE program
 751  * headers and sum of real size of their ELF note segment headers and
 752  * data.
 753  *
 754  * @ehdr_ptr: ELF header
 755  * @nr_ptnote: buffer for the number of PT_NOTE program headers
 756  * @sz_ptnote: buffer for size of unique PT_NOTE program header
 757  *
 758  * This function is used to merge multiple PT_NOTE program headers
 759  * into a unique single one. The resulting unique entry will have
 760  * @sz_ptnote in its phdr->p_mem.
 761  *
 762  * It is assumed that program headers with PT_NOTE type pointed to by
 763  * @ehdr_ptr has already been updated by update_note_header_size_elf64
 764  * and each of PT_NOTE program headers has actual ELF note segment
 765  * size in its p_memsz member.
 766  */
 767 static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
 768                                                  int *nr_ptnote, u64 *sz_ptnote)
 769 {
 770         int i;
 771         Elf64_Phdr *phdr_ptr;
 772 
 773         *nr_ptnote = *sz_ptnote = 0;
 774 
 775         phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
 776         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 777                 if (phdr_ptr->p_type != PT_NOTE)
 778                         continue;
 779                 *nr_ptnote += 1;
 780                 *sz_ptnote += phdr_ptr->p_memsz;
 781         }
 782 
 783         return 0;
 784 }
 785 
 786 /**
 787  * copy_notes_elf64 - copy ELF note segments in a given buffer
 788  *
 789  * @ehdr_ptr: ELF header
 790  * @notes_buf: buffer into which ELF note segments are copied
 791  *
 792  * This function is used to copy ELF note segment in the 1st kernel
 793  * into the buffer @notes_buf in the 2nd kernel. It is assumed that
 794  * size of the buffer @notes_buf is equal to or larger than sum of the
 795  * real ELF note segment headers and data.
 796  *
 797  * It is assumed that program headers with PT_NOTE type pointed to by
 798  * @ehdr_ptr has already been updated by update_note_header_size_elf64
 799  * and each of PT_NOTE program headers has actual ELF note segment
 800  * size in its p_memsz member.
 801  */
 802 static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
 803 {
 804         int i, rc=0;
 805         Elf64_Phdr *phdr_ptr;
 806 
 807         phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
 808 
 809         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 810                 u64 offset;
 811                 if (phdr_ptr->p_type != PT_NOTE)
 812                         continue;
 813                 offset = phdr_ptr->p_offset;
 814                 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
 815                                            &offset);
 816                 if (rc < 0)
 817                         return rc;
 818                 notes_buf += phdr_ptr->p_memsz;
 819         }
 820 
 821         return 0;
 822 }
 823 
 824 /* Merges all the PT_NOTE headers into one. */
 825 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 826                                            char **notes_buf, size_t *notes_sz)
 827 {
 828         int i, nr_ptnote=0, rc=0;
 829         char *tmp;
 830         Elf64_Ehdr *ehdr_ptr;
 831         Elf64_Phdr phdr;
 832         u64 phdr_sz = 0, note_off;
 833 
 834         ehdr_ptr = (Elf64_Ehdr *)elfptr;
 835 
 836         rc = update_note_header_size_elf64(ehdr_ptr);
 837         if (rc < 0)
 838                 return rc;
 839 
 840         rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
 841         if (rc < 0)
 842                 return rc;
 843 
 844         *notes_sz = roundup(phdr_sz, PAGE_SIZE);
 845         *notes_buf = vmcore_alloc_buf(*notes_sz);
 846         if (!*notes_buf)
 847                 return -ENOMEM;
 848 
 849         rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
 850         if (rc < 0)
 851                 return rc;
 852 
 853         /* Prepare merged PT_NOTE program header. */
 854         phdr.p_type    = PT_NOTE;
 855         phdr.p_flags   = 0;
 856         note_off = sizeof(Elf64_Ehdr) +
 857                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 858         phdr.p_offset  = roundup(note_off, PAGE_SIZE);
 859         phdr.p_vaddr   = phdr.p_paddr = 0;
 860         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 861         phdr.p_align   = 0;
 862 
 863         /* Add merged PT_NOTE program header*/
 864         tmp = elfptr + sizeof(Elf64_Ehdr);
 865         memcpy(tmp, &phdr, sizeof(phdr));
 866         tmp += sizeof(phdr);
 867 
 868         /* Remove unwanted PT_NOTE program headers. */
 869         i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 870         *elfsz = *elfsz - i;
 871         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 872         memset(elfptr + *elfsz, 0, i);
 873         *elfsz = roundup(*elfsz, PAGE_SIZE);
 874 
 875         /* Modify e_phnum to reflect merged headers. */
 876         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 877 
 878         /* Store the size of all notes.  We need this to update the note
 879          * header when the device dumps will be added.
 880          */
 881         elfnotes_orig_sz = phdr.p_memsz;
 882 
 883         return 0;
 884 }
 885 
 886 /**
 887  * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
 888  *
 889  * @ehdr_ptr: ELF header
 890  *
 891  * This function updates p_memsz member of each PT_NOTE entry in the
 892  * program header table pointed to by @ehdr_ptr to real size of ELF
 893  * note segment.
 894  */
 895 static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
 896 {
 897         int i, rc=0;
 898         Elf32_Phdr *phdr_ptr;
 899         Elf32_Nhdr *nhdr_ptr;
 900 
 901         phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
 902         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 903                 void *notes_section;
 904                 u64 offset, max_sz, sz, real_sz = 0;
 905                 if (phdr_ptr->p_type != PT_NOTE)
 906                         continue;
 907                 max_sz = phdr_ptr->p_memsz;
 908                 offset = phdr_ptr->p_offset;
 909                 notes_section = kmalloc(max_sz, GFP_KERNEL);
 910                 if (!notes_section)
 911                         return -ENOMEM;
 912                 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
 913                 if (rc < 0) {
 914                         kfree(notes_section);
 915                         return rc;
 916                 }
 917                 nhdr_ptr = notes_section;
 918                 while (nhdr_ptr->n_namesz != 0) {
 919                         sz = sizeof(Elf32_Nhdr) +
 920                                 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
 921                                 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
 922                         if ((real_sz + sz) > max_sz) {
 923                                 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
 924                                         nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
 925                                 break;
 926                         }
 927                         real_sz += sz;
 928                         nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 929                 }
 930                 kfree(notes_section);
 931                 phdr_ptr->p_memsz = real_sz;
 932                 if (real_sz == 0) {
 933                         pr_warn("Warning: Zero PT_NOTE entries found\n");
 934                 }
 935         }
 936 
 937         return 0;
 938 }
 939 
 940 /**
 941  * get_note_number_and_size_elf32 - get the number of PT_NOTE program
 942  * headers and sum of real size of their ELF note segment headers and
 943  * data.
 944  *
 945  * @ehdr_ptr: ELF header
 946  * @nr_ptnote: buffer for the number of PT_NOTE program headers
 947  * @sz_ptnote: buffer for size of unique PT_NOTE program header
 948  *
 949  * This function is used to merge multiple PT_NOTE program headers
 950  * into a unique single one. The resulting unique entry will have
 951  * @sz_ptnote in its phdr->p_mem.
 952  *
 953  * It is assumed that program headers with PT_NOTE type pointed to by
 954  * @ehdr_ptr has already been updated by update_note_header_size_elf32
 955  * and each of PT_NOTE program headers has actual ELF note segment
 956  * size in its p_memsz member.
 957  */
 958 static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
 959                                                  int *nr_ptnote, u64 *sz_ptnote)
 960 {
 961         int i;
 962         Elf32_Phdr *phdr_ptr;
 963 
 964         *nr_ptnote = *sz_ptnote = 0;
 965 
 966         phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
 967         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 968                 if (phdr_ptr->p_type != PT_NOTE)
 969                         continue;
 970                 *nr_ptnote += 1;
 971                 *sz_ptnote += phdr_ptr->p_memsz;
 972         }
 973 
 974         return 0;
 975 }
 976 
 977 /**
 978  * copy_notes_elf32 - copy ELF note segments in a given buffer
 979  *
 980  * @ehdr_ptr: ELF header
 981  * @notes_buf: buffer into which ELF note segments are copied
 982  *
 983  * This function is used to copy ELF note segment in the 1st kernel
 984  * into the buffer @notes_buf in the 2nd kernel. It is assumed that
 985  * size of the buffer @notes_buf is equal to or larger than sum of the
 986  * real ELF note segment headers and data.
 987  *
 988  * It is assumed that program headers with PT_NOTE type pointed to by
 989  * @ehdr_ptr has already been updated by update_note_header_size_elf32
 990  * and each of PT_NOTE program headers has actual ELF note segment
 991  * size in its p_memsz member.
 992  */
 993 static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
 994 {
 995         int i, rc=0;
 996         Elf32_Phdr *phdr_ptr;
 997 
 998         phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
 999 
1000         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1001                 u64 offset;
1002                 if (phdr_ptr->p_type != PT_NOTE)
1003                         continue;
1004                 offset = phdr_ptr->p_offset;
1005                 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
1006                                            &offset);
1007                 if (rc < 0)
1008                         return rc;
1009                 notes_buf += phdr_ptr->p_memsz;
1010         }
1011 
1012         return 0;
1013 }
1014 
1015 /* Merges all the PT_NOTE headers into one. */
1016 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
1017                                            char **notes_buf, size_t *notes_sz)
1018 {
1019         int i, nr_ptnote=0, rc=0;
1020         char *tmp;
1021         Elf32_Ehdr *ehdr_ptr;
1022         Elf32_Phdr phdr;
1023         u64 phdr_sz = 0, note_off;
1024 
1025         ehdr_ptr = (Elf32_Ehdr *)elfptr;
1026 
1027         rc = update_note_header_size_elf32(ehdr_ptr);
1028         if (rc < 0)
1029                 return rc;
1030 
1031         rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
1032         if (rc < 0)
1033                 return rc;
1034 
1035         *notes_sz = roundup(phdr_sz, PAGE_SIZE);
1036         *notes_buf = vmcore_alloc_buf(*notes_sz);
1037         if (!*notes_buf)
1038                 return -ENOMEM;
1039 
1040         rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
1041         if (rc < 0)
1042                 return rc;
1043 
1044         /* Prepare merged PT_NOTE program header. */
1045         phdr.p_type    = PT_NOTE;
1046         phdr.p_flags   = 0;
1047         note_off = sizeof(Elf32_Ehdr) +
1048                         (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
1049         phdr.p_offset  = roundup(note_off, PAGE_SIZE);
1050         phdr.p_vaddr   = phdr.p_paddr = 0;
1051         phdr.p_filesz  = phdr.p_memsz = phdr_sz;
1052         phdr.p_align   = 0;
1053 
1054         /* Add merged PT_NOTE program header*/
1055         tmp = elfptr + sizeof(Elf32_Ehdr);
1056         memcpy(tmp, &phdr, sizeof(phdr));
1057         tmp += sizeof(phdr);
1058 
1059         /* Remove unwanted PT_NOTE program headers. */
1060         i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
1061         *elfsz = *elfsz - i;
1062         memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
1063         memset(elfptr + *elfsz, 0, i);
1064         *elfsz = roundup(*elfsz, PAGE_SIZE);
1065 
1066         /* Modify e_phnum to reflect merged headers. */
1067         ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
1068 
1069         /* Store the size of all notes.  We need this to update the note
1070          * header when the device dumps will be added.
1071          */
1072         elfnotes_orig_sz = phdr.p_memsz;
1073 
1074         return 0;
1075 }
1076 
1077 /* Add memory chunks represented by program headers to vmcore list. Also update
1078  * the new offset fields of exported program headers. */
1079 static int __init process_ptload_program_headers_elf64(char *elfptr,
1080                                                 size_t elfsz,
1081                                                 size_t elfnotes_sz,
1082                                                 struct list_head *vc_list)
1083 {
1084         int i;
1085         Elf64_Ehdr *ehdr_ptr;
1086         Elf64_Phdr *phdr_ptr;
1087         loff_t vmcore_off;
1088         struct vmcore *new;
1089 
1090         ehdr_ptr = (Elf64_Ehdr *)elfptr;
1091         phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
1092 
1093         /* Skip Elf header, program headers and Elf note segment. */
1094         vmcore_off = elfsz + elfnotes_sz;
1095 
1096         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1097                 u64 paddr, start, end, size;
1098 
1099                 if (phdr_ptr->p_type != PT_LOAD)
1100                         continue;
1101 
1102                 paddr = phdr_ptr->p_offset;
1103                 start = rounddown(paddr, PAGE_SIZE);
1104                 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1105                 size = end - start;
1106 
1107                 /* Add this contiguous chunk of memory to vmcore list.*/
1108                 new = get_new_element();
1109                 if (!new)
1110                         return -ENOMEM;
1111                 new->paddr = start;
1112                 new->size = size;
1113                 list_add_tail(&new->list, vc_list);
1114 
1115                 /* Update the program header offset. */
1116                 phdr_ptr->p_offset = vmcore_off + (paddr - start);
1117                 vmcore_off = vmcore_off + size;
1118         }
1119         return 0;
1120 }
1121 
1122 static int __init process_ptload_program_headers_elf32(char *elfptr,
1123                                                 size_t elfsz,
1124                                                 size_t elfnotes_sz,
1125                                                 struct list_head *vc_list)
1126 {
1127         int i;
1128         Elf32_Ehdr *ehdr_ptr;
1129         Elf32_Phdr *phdr_ptr;
1130         loff_t vmcore_off;
1131         struct vmcore *new;
1132 
1133         ehdr_ptr = (Elf32_Ehdr *)elfptr;
1134         phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
1135 
1136         /* Skip Elf header, program headers and Elf note segment. */
1137         vmcore_off = elfsz + elfnotes_sz;
1138 
1139         for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1140                 u64 paddr, start, end, size;
1141 
1142                 if (phdr_ptr->p_type != PT_LOAD)
1143                         continue;
1144 
1145                 paddr = phdr_ptr->p_offset;
1146                 start = rounddown(paddr, PAGE_SIZE);
1147                 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1148                 size = end - start;
1149 
1150                 /* Add this contiguous chunk of memory to vmcore list.*/
1151                 new = get_new_element();
1152                 if (!new)
1153                         return -ENOMEM;
1154                 new->paddr = start;
1155                 new->size = size;
1156                 list_add_tail(&new->list, vc_list);
1157 
1158                 /* Update the program header offset */
1159                 phdr_ptr->p_offset = vmcore_off + (paddr - start);
1160                 vmcore_off = vmcore_off + size;
1161         }
1162         return 0;
1163 }
1164 
1165 /* Sets offset fields of vmcore elements. */
1166 static void set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
1167                                     struct list_head *vc_list)
1168 {
1169         loff_t vmcore_off;
1170         struct vmcore *m;
1171 
1172         /* Skip Elf header, program headers and Elf note segment. */
1173         vmcore_off = elfsz + elfnotes_sz;
1174 
1175         list_for_each_entry(m, vc_list, list) {
1176                 m->offset = vmcore_off;
1177                 vmcore_off += m->size;
1178         }
1179 }
1180 
1181 static void free_elfcorebuf(void)
1182 {
1183         free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
1184         elfcorebuf = NULL;
1185         vfree(elfnotes_buf);
1186         elfnotes_buf = NULL;
1187 }
1188 
1189 static int __init parse_crash_elf64_headers(void)
1190 {
1191         int rc=0;
1192         Elf64_Ehdr ehdr;
1193         u64 addr;
1194 
1195         addr = elfcorehdr_addr;
1196 
1197         /* Read Elf header */
1198         rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
1199         if (rc < 0)
1200                 return rc;
1201 
1202         /* Do some basic Verification. */
1203         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1204                 (ehdr.e_type != ET_CORE) ||
1205                 !vmcore_elf64_check_arch(&ehdr) ||
1206                 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
1207                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1208                 ehdr.e_version != EV_CURRENT ||
1209                 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
1210                 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
1211                 ehdr.e_phnum == 0) {
1212                 pr_warn("Warning: Core image elf header is not sane\n");
1213                 return -EINVAL;
1214         }
1215 
1216         /* Read in all elf headers. */
1217         elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
1218                                 ehdr.e_phnum * sizeof(Elf64_Phdr);
1219         elfcorebuf_sz = elfcorebuf_sz_orig;
1220         elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1221                                               get_order(elfcorebuf_sz_orig));
1222         if (!elfcorebuf)
1223                 return -ENOMEM;
1224         addr = elfcorehdr_addr;
1225         rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1226         if (rc < 0)
1227                 goto fail;
1228 
1229         /* Merge all PT_NOTE headers into one. */
1230         rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
1231                                       &elfnotes_buf, &elfnotes_sz);
1232         if (rc)
1233                 goto fail;
1234         rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
1235                                                   elfnotes_sz, &vmcore_list);
1236         if (rc)
1237                 goto fail;
1238         set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1239         return 0;
1240 fail:
1241         free_elfcorebuf();
1242         return rc;
1243 }
1244 
1245 static int __init parse_crash_elf32_headers(void)
1246 {
1247         int rc=0;
1248         Elf32_Ehdr ehdr;
1249         u64 addr;
1250 
1251         addr = elfcorehdr_addr;
1252 
1253         /* Read Elf header */
1254         rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
1255         if (rc < 0)
1256                 return rc;
1257 
1258         /* Do some basic Verification. */
1259         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1260                 (ehdr.e_type != ET_CORE) ||
1261                 !vmcore_elf32_check_arch(&ehdr) ||
1262                 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
1263                 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1264                 ehdr.e_version != EV_CURRENT ||
1265                 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1266                 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1267                 ehdr.e_phnum == 0) {
1268                 pr_warn("Warning: Core image elf header is not sane\n");
1269                 return -EINVAL;
1270         }
1271 
1272         /* Read in all elf headers. */
1273         elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1274         elfcorebuf_sz = elfcorebuf_sz_orig;
1275         elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1276                                               get_order(elfcorebuf_sz_orig));
1277         if (!elfcorebuf)
1278                 return -ENOMEM;
1279         addr = elfcorehdr_addr;
1280         rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1281         if (rc < 0)
1282                 goto fail;
1283 
1284         /* Merge all PT_NOTE headers into one. */
1285         rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1286                                       &elfnotes_buf, &elfnotes_sz);
1287         if (rc)
1288                 goto fail;
1289         rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1290                                                   elfnotes_sz, &vmcore_list);
1291         if (rc)
1292                 goto fail;
1293         set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1294         return 0;
1295 fail:
1296         free_elfcorebuf();
1297         return rc;
1298 }
1299 
1300 static int __init parse_crash_elf_headers(void)
1301 {
1302         unsigned char e_ident[EI_NIDENT];
1303         u64 addr;
1304         int rc=0;
1305 
1306         addr = elfcorehdr_addr;
1307         rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1308         if (rc < 0)
1309                 return rc;
1310         if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1311                 pr_warn("Warning: Core image elf header not found\n");
1312                 return -EINVAL;
1313         }
1314 
1315         if (e_ident[EI_CLASS] == ELFCLASS64) {
1316                 rc = parse_crash_elf64_headers();
1317                 if (rc)
1318                         return rc;
1319         } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1320                 rc = parse_crash_elf32_headers();
1321                 if (rc)
1322                         return rc;
1323         } else {
1324                 pr_warn("Warning: Core image elf header is not sane\n");
1325                 return -EINVAL;
1326         }
1327 
1328         /* Determine vmcore size. */
1329         vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1330                                       &vmcore_list);
1331 
1332         return 0;
1333 }
1334 
1335 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1336 /**
1337  * vmcoredd_write_header - Write vmcore device dump header at the
1338  * beginning of the dump's buffer.
1339  * @buf: Output buffer where the note is written
1340  * @data: Dump info
1341  * @size: Size of the dump
1342  *
1343  * Fills beginning of the dump's buffer with vmcore device dump header.
1344  */
1345 static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data,
1346                                   u32 size)
1347 {
1348         struct vmcoredd_header *vdd_hdr = (struct vmcoredd_header *)buf;
1349 
1350         vdd_hdr->n_namesz = sizeof(vdd_hdr->name);
1351         vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name);
1352         vdd_hdr->n_type = NT_VMCOREDD;
1353 
1354         strncpy((char *)vdd_hdr->name, VMCOREDD_NOTE_NAME,
1355                 sizeof(vdd_hdr->name));
1356         memcpy(vdd_hdr->dump_name, data->dump_name, sizeof(vdd_hdr->dump_name));
1357 }
1358 
1359 /**
1360  * vmcoredd_update_program_headers - Update all Elf program headers
1361  * @elfptr: Pointer to elf header
1362  * @elfnotesz: Size of elf notes aligned to page size
1363  * @vmcoreddsz: Size of device dumps to be added to elf note header
1364  *
1365  * Determine type of Elf header (Elf64 or Elf32) and update the elf note size.
1366  * Also update the offsets of all the program headers after the elf note header.
1367  */
1368 static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz,
1369                                             size_t vmcoreddsz)
1370 {
1371         unsigned char *e_ident = (unsigned char *)elfptr;
1372         u64 start, end, size;
1373         loff_t vmcore_off;
1374         u32 i;
1375 
1376         vmcore_off = elfcorebuf_sz + elfnotesz;
1377 
1378         if (e_ident[EI_CLASS] == ELFCLASS64) {
1379                 Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr;
1380                 Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr));
1381 
1382                 /* Update all program headers */
1383                 for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1384                         if (phdr->p_type == PT_NOTE) {
1385                                 /* Update note size */
1386                                 phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1387                                 phdr->p_filesz = phdr->p_memsz;
1388                                 continue;
1389                         }
1390 
1391                         start = rounddown(phdr->p_offset, PAGE_SIZE);
1392                         end = roundup(phdr->p_offset + phdr->p_memsz,
1393                                       PAGE_SIZE);
1394                         size = end - start;
1395                         phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1396                         vmcore_off += size;
1397                 }
1398         } else {
1399                 Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr;
1400                 Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr));
1401 
1402                 /* Update all program headers */
1403                 for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1404                         if (phdr->p_type == PT_NOTE) {
1405                                 /* Update note size */
1406                                 phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1407                                 phdr->p_filesz = phdr->p_memsz;
1408                                 continue;
1409                         }
1410 
1411                         start = rounddown(phdr->p_offset, PAGE_SIZE);
1412                         end = roundup(phdr->p_offset + phdr->p_memsz,
1413                                       PAGE_SIZE);
1414                         size = end - start;
1415                         phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1416                         vmcore_off += size;
1417                 }
1418         }
1419 }
1420 
1421 /**
1422  * vmcoredd_update_size - Update the total size of the device dumps and update
1423  * Elf header
1424  * @dump_size: Size of the current device dump to be added to total size
1425  *
1426  * Update the total size of all the device dumps and update the Elf program
1427  * headers. Calculate the new offsets for the vmcore list and update the
1428  * total vmcore size.
1429  */
1430 static void vmcoredd_update_size(size_t dump_size)
1431 {
1432         vmcoredd_orig_sz += dump_size;
1433         elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz;
1434         vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz,
1435                                         vmcoredd_orig_sz);
1436 
1437         /* Update vmcore list offsets */
1438         set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1439 
1440         vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1441                                       &vmcore_list);
1442         proc_vmcore->size = vmcore_size;
1443 }
1444 
1445 /**
1446  * vmcore_add_device_dump - Add a buffer containing device dump to vmcore
1447  * @data: dump info.
1448  *
1449  * Allocate a buffer and invoke the calling driver's dump collect routine.
1450  * Write Elf note at the beginning of the buffer to indicate vmcore device
1451  * dump and add the dump to global list.
1452  */
1453 int vmcore_add_device_dump(struct vmcoredd_data *data)
1454 {
1455         struct vmcoredd_node *dump;
1456         void *buf = NULL;
1457         size_t data_size;
1458         int ret;
1459 
1460         if (vmcoredd_disabled) {
1461                 pr_err_once("Device dump is disabled\n");
1462                 return -EINVAL;
1463         }
1464 
1465         if (!data || !strlen(data->dump_name) ||
1466             !data->vmcoredd_callback || !data->size)
1467                 return -EINVAL;
1468 
1469         dump = vzalloc(sizeof(*dump));
1470         if (!dump) {
1471                 ret = -ENOMEM;
1472                 goto out_err;
1473         }
1474 
1475         /* Keep size of the buffer page aligned so that it can be mmaped */
1476         data_size = roundup(sizeof(struct vmcoredd_header) + data->size,
1477                             PAGE_SIZE);
1478 
1479         /* Allocate buffer for driver's to write their dumps */
1480         buf = vmcore_alloc_buf(data_size);
1481         if (!buf) {
1482                 ret = -ENOMEM;
1483                 goto out_err;
1484         }
1485 
1486         vmcoredd_write_header(buf, data, data_size -
1487                               sizeof(struct vmcoredd_header));
1488 
1489         /* Invoke the driver's dump collection routing */
1490         ret = data->vmcoredd_callback(data, buf +
1491                                       sizeof(struct vmcoredd_header));
1492         if (ret)
1493                 goto out_err;
1494 
1495         dump->buf = buf;
1496         dump->size = data_size;
1497 
1498         /* Add the dump to driver sysfs list */
1499         mutex_lock(&vmcoredd_mutex);
1500         list_add_tail(&dump->list, &vmcoredd_list);
1501         mutex_unlock(&vmcoredd_mutex);
1502 
1503         vmcoredd_update_size(data_size);
1504         return 0;
1505 
1506 out_err:
1507         if (buf)
1508                 vfree(buf);
1509 
1510         if (dump)
1511                 vfree(dump);
1512 
1513         return ret;
1514 }
1515 EXPORT_SYMBOL(vmcore_add_device_dump);
1516 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1517 
1518 /* Free all dumps in vmcore device dump list */
1519 static void vmcore_free_device_dumps(void)
1520 {
1521 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1522         mutex_lock(&vmcoredd_mutex);
1523         while (!list_empty(&vmcoredd_list)) {
1524                 struct vmcoredd_node *dump;
1525 
1526                 dump = list_first_entry(&vmcoredd_list, struct vmcoredd_node,
1527                                         list);
1528                 list_del(&dump->list);
1529                 vfree(dump->buf);
1530                 vfree(dump);
1531         }
1532         mutex_unlock(&vmcoredd_mutex);
1533 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1534 }
1535 
1536 /* Init function for vmcore module. */
1537 static int __init vmcore_init(void)
1538 {
1539         int rc = 0;
1540 
1541         /* Allow architectures to allocate ELF header in 2nd kernel */
1542         rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1543         if (rc)
1544                 return rc;
1545         /*
1546          * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1547          * then capture the dump.
1548          */
1549         if (!(is_vmcore_usable()))
1550                 return rc;
1551         rc = parse_crash_elf_headers();
1552         if (rc) {
1553                 pr_warn("Kdump: vmcore not initialized\n");
1554                 return rc;
1555         }
1556         elfcorehdr_free(elfcorehdr_addr);
1557         elfcorehdr_addr = ELFCORE_ADDR_ERR;
1558 
1559         proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
1560         if (proc_vmcore)
1561                 proc_vmcore->size = vmcore_size;
1562         return 0;
1563 }
1564 fs_initcall(vmcore_init);
1565 
1566 /* Cleanup function for vmcore module. */
1567 void vmcore_cleanup(void)
1568 {
1569         if (proc_vmcore) {
1570                 proc_remove(proc_vmcore);
1571                 proc_vmcore = NULL;
1572         }
1573 
1574         /* clear the vmcore list. */
1575         while (!list_empty(&vmcore_list)) {
1576                 struct vmcore *m;
1577 
1578                 m = list_first_entry(&vmcore_list, struct vmcore, list);
1579                 list_del(&m->list);
1580                 kfree(m);
1581         }
1582         free_elfcorebuf();
1583 
1584         /* clear vmcore device dump list */
1585         vmcore_free_device_dumps();
1586 }
/* [<][>][^][v][top][bottom][index][help] */
root/fs/proc/vmcore.c

DEFINITIONS
