fs/proc/kcore.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *      fs/proc/kcore.c kernel ELF core dumper
   4  *
   5  *      Modelled on fs/exec.c:aout_core_dump()
   6  *      Jeremy Fitzhardinge <[email protected]>
   7  *      ELF version written by David Howells <[email protected]>
   8  *      Modified and incorporated into 2.3.x by Tigran Aivazian <[email protected]>
   9  *      Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <[email protected]>
  10  *      Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <[email protected]>
  11  */
  12
  13 #include <linux/crash_core.h>
  14 #include <linux/mm.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/kcore.h>
  17 #include <linux/user.h>
  18 #include <linux/capability.h>
  19 #include <linux/elf.h>
  20 #include <linux/elfcore.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/highmem.h>
  23 #include <linux/printk.h>
  24 #include <linux/memblock.h>
  25 #include <linux/init.h>
  26 #include <linux/slab.h>
  27 #include <linux/uaccess.h>
  28 #include <asm/io.h>
  29 #include <linux/list.h>
  30 #include <linux/ioport.h>
  31 #include <linux/memory.h>
  32 #include <linux/sched/task.h>
  33 #include <linux/security.h>
  34 #include <asm/sections.h>
  35 #include "internal.h"
  36
  37 #define CORE_STR "CORE"
  38
  39 #ifndef ELF_CORE_EFLAGS
  40 #define ELF_CORE_EFLAGS 0
  41 #endif
  42
  43 static struct proc_dir_entry *proc_root_kcore;
  44
  45
  46 #ifndef kc_vaddr_to_offset
  47 #define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
  48 #endif
  49 #ifndef kc_offset_to_vaddr
  50 #define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
  51 #endif
  52
  53 static LIST_HEAD(kclist_head);
  54 static DECLARE_RWSEM(kclist_lock);
  55 static int kcore_need_update = 1;
  56
  57 /*
  58  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  59  * Same as oldmem_pfn_is_ram in vmcore
  60  */
  61 static int (*mem_pfn_is_ram)(unsigned long pfn);
  62
  63 int __init register_mem_pfn_is_ram(int (*fn)(unsigned long pfn))
  64 {
  65         if (mem_pfn_is_ram)
  66                 return -EBUSY;
  67         mem_pfn_is_ram = fn;
  68         return 0;
  69 }
  70
  71 static int pfn_is_ram(unsigned long pfn)
  72 {
  73         if (mem_pfn_is_ram)
  74                 return mem_pfn_is_ram(pfn);
  75         else
  76                 return 1;
  77 }
  78
  79 /* This doesn't grab kclist_lock, so it should only be used at init time. */
  80 void __init kclist_add(struct kcore_list *new, void *addr, size_t size,
  81                        int type)
  82 {
  83         new->addr = (unsigned long)addr;
  84         new->size = size;
  85         new->type = type;
  86
  87         list_add_tail(&new->list, &kclist_head);
  88 }
  89
  90 static size_t get_kcore_size(int *nphdr, size_t *phdrs_len, size_t *notes_len,
  91                              size_t *data_offset)
  92 {
  93         size_t try, size;
  94         struct kcore_list *m;
  95
  96         *nphdr = 1; /* PT_NOTE */
  97         size = 0;
  98
  99         list_for_each_entry(m, &kclist_head, list) {
 100                 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
 101                 if (try > size)
 102                         size = try;
 103                 *nphdr = *nphdr + 1;
 104         }
 105
 106         *phdrs_len = *nphdr * sizeof(struct elf_phdr);
 107         *notes_len = (4 * sizeof(struct elf_note) +
 108                       3 * ALIGN(sizeof(CORE_STR), 4) +
 109                       VMCOREINFO_NOTE_NAME_BYTES +
 110                       ALIGN(sizeof(struct elf_prstatus), 4) +
 111                       ALIGN(sizeof(struct elf_prpsinfo), 4) +
 112                       ALIGN(arch_task_struct_size, 4) +
 113                       ALIGN(vmcoreinfo_size, 4));
 114         *data_offset = PAGE_ALIGN(sizeof(struct elfhdr) + *phdrs_len +
 115                                   *notes_len);
 116         return *data_offset + size;
 117 }
 118
 119 #ifdef CONFIG_HIGHMEM
 120 /*
 121  * If no highmem, we can assume [0...max_low_pfn) continuous range of memory
 122  * because memory hole is not as big as !HIGHMEM case.
 123  * (HIGHMEM is special because part of memory is _invisible_ from the kernel.)
 124  */
 125 static int kcore_ram_list(struct list_head *head)
 126 {
 127         struct kcore_list *ent;
 128
 129         ent = kmalloc(sizeof(*ent), GFP_KERNEL);
 130         if (!ent)
 131                 return -ENOMEM;
 132         ent->addr = (unsigned long)__va(0);
 133         ent->size = max_low_pfn << PAGE_SHIFT;
 134         ent->type = KCORE_RAM;
 135         list_add(&ent->list, head);
 136         return 0;
 137 }
 138
 139 #else /* !CONFIG_HIGHMEM */
 140
 141 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 142 /* calculate vmemmap's address from given system ram pfn and register it */
 143 static int
 144 get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
 145 {
 146         unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
 147         unsigned long nr_pages = ent->size >> PAGE_SHIFT;
 148         unsigned long start, end;
 149         struct kcore_list *vmm, *tmp;
 150
 151
 152         start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
 153         end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
 154         end = PAGE_ALIGN(end);
 155         /* overlap check (because we have to align page */
 156         list_for_each_entry(tmp, head, list) {
 157                 if (tmp->type != KCORE_VMEMMAP)
 158                         continue;
 159                 if (start < tmp->addr + tmp->size)
 160                         if (end > tmp->addr)
 161                                 end = tmp->addr;
 162         }
 163         if (start < end) {
 164                 vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
 165                 if (!vmm)
 166                         return 0;
 167                 vmm->addr = start;
 168                 vmm->size = end - start;
 169                 vmm->type = KCORE_VMEMMAP;
 170                 list_add_tail(&vmm->list, head);
 171         }
 172         return 1;
 173
 174 }
 175 #else
 176 static int
 177 get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
 178 {
 179         return 1;
 180 }
 181
 182 #endif
 183
 184 static int
 185 kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
 186 {
 187         struct list_head *head = (struct list_head *)arg;
 188         struct kcore_list *ent;
 189         struct page *p;
 190
 191         if (!pfn_valid(pfn))
 192                 return 1;
 193
 194         p = pfn_to_page(pfn);
 195
 196         ent = kmalloc(sizeof(*ent), GFP_KERNEL);
 197         if (!ent)
 198                 return -ENOMEM;
 199         ent->addr = (unsigned long)page_to_virt(p);
 200         ent->size = nr_pages << PAGE_SHIFT;
 201
 202         if (!virt_addr_valid(ent->addr))
 203                 goto free_out;
 204
 205         /* cut not-mapped area. ....from ppc-32 code. */
 206         if (ULONG_MAX - ent->addr < ent->size)
 207                 ent->size = ULONG_MAX - ent->addr;
 208
 209         /*
 210          * We've already checked virt_addr_valid so we know this address
 211          * is a valid pointer, therefore we can check against it to determine
 212          * if we need to trim
 213          */
 214         if (VMALLOC_START > ent->addr) {
 215                 if (VMALLOC_START - ent->addr < ent->size)
 216                         ent->size = VMALLOC_START - ent->addr;
 217         }
 218
 219         ent->type = KCORE_RAM;
 220         list_add_tail(&ent->list, head);
 221
 222         if (!get_sparsemem_vmemmap_info(ent, head)) {
 223                 list_del(&ent->list);
 224                 goto free_out;
 225         }
 226
 227         return 0;
 228 free_out:
 229         kfree(ent);
 230         return 1;
 231 }
 232
 233 static int kcore_ram_list(struct list_head *list)
 234 {
 235         int nid, ret;
 236         unsigned long end_pfn;
 237
 238         /* Not inialized....update now */
 239         /* find out "max pfn" */
 240         end_pfn = 0;
 241         for_each_node_state(nid, N_MEMORY) {
 242                 unsigned long node_end;
 243                 node_end = node_end_pfn(nid);
 244                 if (end_pfn < node_end)
 245                         end_pfn = node_end;
 246         }
 247         /* scan 0 to max_pfn */
 248         ret = walk_system_ram_range(0, end_pfn, list, kclist_add_private);
 249         if (ret)
 250                 return -ENOMEM;
 251         return 0;
 252 }
 253 #endif /* CONFIG_HIGHMEM */
 254
 255 static int kcore_update_ram(void)
 256 {
 257         LIST_HEAD(list);
 258         LIST_HEAD(garbage);
 259         int nphdr;
 260         size_t phdrs_len, notes_len, data_offset;
 261         struct kcore_list *tmp, *pos;
 262         int ret = 0;
 263
 264         down_write(&kclist_lock);
 265         if (!xchg(&kcore_need_update, 0))
 266                 goto out;
 267
 268         ret = kcore_ram_list(&list);
 269         if (ret) {
 270                 /* Couldn't get the RAM list, try again next time. */
 271                 WRITE_ONCE(kcore_need_update, 1);
 272                 list_splice_tail(&list, &garbage);
 273                 goto out;
 274         }
 275
 276         list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
 277                 if (pos->type == KCORE_RAM || pos->type == KCORE_VMEMMAP)
 278                         list_move(&pos->list, &garbage);
 279         }
 280         list_splice_tail(&list, &kclist_head);
 281
 282         proc_root_kcore->size = get_kcore_size(&nphdr, &phdrs_len, &notes_len,
 283                                                &data_offset);
 284
 285 out:
 286         up_write(&kclist_lock);
 287         list_for_each_entry_safe(pos, tmp, &garbage, list) {
 288                 list_del(&pos->list);
 289                 kfree(pos);
 290         }
 291         return ret;
 292 }
 293
 294 static void append_kcore_note(char *notes, size_t *i, const char *name,
 295                               unsigned int type, const void *desc,
 296                               size_t descsz)
 297 {
 298         struct elf_note *note = (struct elf_note *)&notes[*i];
 299
 300         note->n_namesz = strlen(name) + 1;
 301         note->n_descsz = descsz;
 302         note->n_type = type;
 303         *i += sizeof(*note);
 304         memcpy(&notes[*i], name, note->n_namesz);
 305         *i = ALIGN(*i + note->n_namesz, 4);
 306         memcpy(&notes[*i], desc, descsz);
 307         *i = ALIGN(*i + descsz, 4);
 308 }
 309
 310 static ssize_t
 311 read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
 312 {
 313         char *buf = file->private_data;
 314         size_t phdrs_offset, notes_offset, data_offset;
 315         size_t page_offline_frozen = 1;
 316         size_t phdrs_len, notes_len;
 317         struct kcore_list *m;
 318         size_t tsz;
 319         int nphdr;
 320         unsigned long start;
 321         size_t orig_buflen = buflen;
 322         int ret = 0;
 323
 324         down_read(&kclist_lock);
 325         /*
 326          * Don't race against drivers that set PageOffline() and expect no
 327          * further page access.
 328          */
 329         page_offline_freeze();
 330
 331         get_kcore_size(&nphdr, &phdrs_len, &notes_len, &data_offset);
 332         phdrs_offset = sizeof(struct elfhdr);
 333         notes_offset = phdrs_offset + phdrs_len;
 334
 335         /* ELF file header. */
 336         if (buflen && *fpos < sizeof(struct elfhdr)) {
 337                 struct elfhdr ehdr = {
 338                         .e_ident = {
 339                                 [EI_MAG0] = ELFMAG0,
 340                                 [EI_MAG1] = ELFMAG1,
 341                                 [EI_MAG2] = ELFMAG2,
 342                                 [EI_MAG3] = ELFMAG3,
 343                                 [EI_CLASS] = ELF_CLASS,
 344                                 [EI_DATA] = ELF_DATA,
 345                                 [EI_VERSION] = EV_CURRENT,
 346                                 [EI_OSABI] = ELF_OSABI,
 347                         },
 348                         .e_type = ET_CORE,
 349                         .e_machine = ELF_ARCH,
 350                         .e_version = EV_CURRENT,
 351                         .e_phoff = sizeof(struct elfhdr),
 352                         .e_flags = ELF_CORE_EFLAGS,
 353                         .e_ehsize = sizeof(struct elfhdr),
 354                         .e_phentsize = sizeof(struct elf_phdr),
 355                         .e_phnum = nphdr,
 356                 };
 357
 358                 tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos);
 359                 if (copy_to_user(buffer, (char *)&ehdr + *fpos, tsz)) {
 360                         ret = -EFAULT;
 361                         goto out;
 362                 }
 363
 364                 buffer += tsz;
 365                 buflen -= tsz;
 366                 *fpos += tsz;
 367         }
 368
 369         /* ELF program headers. */
 370         if (buflen && *fpos < phdrs_offset + phdrs_len) {
 371                 struct elf_phdr *phdrs, *phdr;
 372
 373                 phdrs = kzalloc(phdrs_len, GFP_KERNEL);
 374                 if (!phdrs) {
 375                         ret = -ENOMEM;
 376                         goto out;
 377                 }
 378
 379                 phdrs[0].p_type = PT_NOTE;
 380                 phdrs[0].p_offset = notes_offset;
 381                 phdrs[0].p_filesz = notes_len;
 382
 383                 phdr = &phdrs[1];
 384                 list_for_each_entry(m, &kclist_head, list) {
 385                         phdr->p_type = PT_LOAD;
 386                         phdr->p_flags = PF_R | PF_W | PF_X;
 387                         phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;
 388                         phdr->p_vaddr = (size_t)m->addr;
 389                         if (m->type == KCORE_RAM)
 390                                 phdr->p_paddr = __pa(m->addr);
 391                         else if (m->type == KCORE_TEXT)
 392                                 phdr->p_paddr = __pa_symbol(m->addr);
 393                         else
 394                                 phdr->p_paddr = (elf_addr_t)-1;
 395                         phdr->p_filesz = phdr->p_memsz = m->size;
 396                         phdr->p_align = PAGE_SIZE;
 397                         phdr++;
 398                 }
 399
 400                 tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos);
 401                 if (copy_to_user(buffer, (char *)phdrs + *fpos - phdrs_offset,
 402                                  tsz)) {
 403                         kfree(phdrs);
 404                         ret = -EFAULT;
 405                         goto out;
 406                 }
 407                 kfree(phdrs);
 408
 409                 buffer += tsz;
 410                 buflen -= tsz;
 411                 *fpos += tsz;
 412         }
 413
 414         /* ELF note segment. */
 415         if (buflen && *fpos < notes_offset + notes_len) {
 416                 struct elf_prstatus prstatus = {};
 417                 struct elf_prpsinfo prpsinfo = {
 418                         .pr_sname = 'R',
 419                         .pr_fname = "vmlinux",
 420                 };
 421                 char *notes;
 422                 size_t i = 0;
 423
 424                 strlcpy(prpsinfo.pr_psargs, saved_command_line,
 425                         sizeof(prpsinfo.pr_psargs));
 426
 427                 notes = kzalloc(notes_len, GFP_KERNEL);
 428                 if (!notes) {
 429                         ret = -ENOMEM;
 430                         goto out;
 431                 }
 432
 433                 append_kcore_note(notes, &i, CORE_STR, NT_PRSTATUS, &prstatus,
 434                                   sizeof(prstatus));
 435                 append_kcore_note(notes, &i, CORE_STR, NT_PRPSINFO, &prpsinfo,
 436                                   sizeof(prpsinfo));
 437                 append_kcore_note(notes, &i, CORE_STR, NT_TASKSTRUCT, current,
 438                                   arch_task_struct_size);
 439                 /*
 440                  * vmcoreinfo_size is mostly constant after init time, but it
 441                  * can be changed by crash_save_vmcoreinfo(). Racing here with a
 442                  * panic on another CPU before the machine goes down is insanely
 443                  * unlikely, but it's better to not leave potential buffer
 444                  * overflows lying around, regardless.
 445                  */
 446                 append_kcore_note(notes, &i, VMCOREINFO_NOTE_NAME, 0,
 447                                   vmcoreinfo_data,
 448                                   min(vmcoreinfo_size, notes_len - i));
 449
 450                 tsz = min_t(size_t, buflen, notes_offset + notes_len - *fpos);
 451                 if (copy_to_user(buffer, notes + *fpos - notes_offset, tsz)) {
 452                         kfree(notes);
 453                         ret = -EFAULT;
 454                         goto out;
 455                 }
 456                 kfree(notes);
 457
 458                 buffer += tsz;
 459                 buflen -= tsz;
 460                 *fpos += tsz;
 461         }
 462
 463         /*
 464          * Check to see if our file offset matches with any of
 465          * the addresses in the elf_phdr on our list.
 466          */
 467         start = kc_offset_to_vaddr(*fpos - data_offset);
 468         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 469                 tsz = buflen;
 470
 471         m = NULL;
 472         while (buflen) {
 473                 struct page *page;
 474                 unsigned long pfn;
 475
 476                 /*
 477                  * If this is the first iteration or the address is not within
 478                  * the previous entry, search for a matching entry.
 479                  */
 480                 if (!m || start < m->addr || start >= m->addr + m->size) {
 481                         struct kcore_list *iter;
 482
 483                         m = NULL;
 484                         list_for_each_entry(iter, &kclist_head, list) {
 485                                 if (start >= iter->addr &&
 486                                     start < iter->addr + iter->size) {
 487                                         m = iter;
 488                                         break;
 489                                 }
 490                         }
 491                 }
 492
 493                 if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) {
 494                         page_offline_thaw();
 495                         cond_resched();
 496                         page_offline_freeze();
 497                 }
 498
 499                 if (!m) {
 500                         if (clear_user(buffer, tsz)) {
 501                                 ret = -EFAULT;
 502                                 goto out;
 503                         }
 504                         goto skip;
 505                 }
 506
 507                 switch (m->type) {
 508                 case KCORE_VMALLOC:
 509                         vread(buf, (char *)start, tsz);
 510                         /* we have to zero-fill user buffer even if no read */
 511                         if (copy_to_user(buffer, buf, tsz)) {
 512                                 ret = -EFAULT;
 513                                 goto out;
 514                         }
 515                         break;
 516                 case KCORE_USER:
 517                         /* User page is handled prior to normal kernel page: */
 518                         if (copy_to_user(buffer, (char *)start, tsz)) {
 519                                 ret = -EFAULT;
 520                                 goto out;
 521                         }
 522                         break;
 523                 case KCORE_RAM:
 524                         pfn = __pa(start) >> PAGE_SHIFT;
 525                         page = pfn_to_online_page(pfn);
 526
 527                         /*
 528                          * Don't read offline sections, logically offline pages
 529                          * (e.g., inflated in a balloon), hwpoisoned pages,
 530                          * and explicitly excluded physical ranges.
 531                          */
 532                         if (!page || PageOffline(page) ||
 533                             is_page_hwpoison(page) || !pfn_is_ram(pfn)) {
 534                                 if (clear_user(buffer, tsz)) {
 535                                         ret = -EFAULT;
 536                                         goto out;
 537                                 }
 538                                 break;
 539                         }
 540                         fallthrough;
 541                 case KCORE_VMEMMAP:
 542                 case KCORE_TEXT:
 543                         /*
 544                          * Using bounce buffer to bypass the
 545                          * hardened user copy kernel text checks.
 546                          */
 547                         if (copy_from_kernel_nofault(buf, (void *)start, tsz)) {
 548                                 if (clear_user(buffer, tsz)) {
 549                                         ret = -EFAULT;
 550                                         goto out;
 551                                 }
 552                         } else {
 553                                 if (copy_to_user(buffer, buf, tsz)) {
 554                                         ret = -EFAULT;
 555                                         goto out;
 556                                 }
 557                         }
 558                         break;
 559                 default:
 560                         pr_warn_once("Unhandled KCORE type: %d\n", m->type);
 561                         if (clear_user(buffer, tsz)) {
 562                                 ret = -EFAULT;
 563                                 goto out;
 564                         }
 565                 }
 566 skip:
 567                 buflen -= tsz;
 568                 *fpos += tsz;
 569                 buffer += tsz;
 570                 start += tsz;
 571                 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
 572         }
 573
 574 out:
 575         page_offline_thaw();
 576         up_read(&kclist_lock);
 577         if (ret)
 578                 return ret;
 579         return orig_buflen - buflen;
 580 }
 581
 582 static int open_kcore(struct inode *inode, struct file *filp)
 583 {
 584         int ret = security_locked_down(LOCKDOWN_KCORE);
 585
 586         if (!capable(CAP_SYS_RAWIO))
 587                 return -EPERM;
 588
 589         if (ret)
 590                 return ret;
 591
 592         filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
 593         if (!filp->private_data)
 594                 return -ENOMEM;
 595
 596         if (kcore_need_update)
 597                 kcore_update_ram();
 598         if (i_size_read(inode) != proc_root_kcore->size) {
 599                 inode_lock(inode);
 600                 i_size_write(inode, proc_root_kcore->size);
 601                 inode_unlock(inode);
 602         }
 603         return 0;
 604 }
 605
 606 static int release_kcore(struct inode *inode, struct file *file)
 607 {
 608         kfree(file->private_data);
 609         return 0;
 610 }
 611
 612 static const struct proc_ops kcore_proc_ops = {
 613         .proc_read      = read_kcore,
 614         .proc_open      = open_kcore,
 615         .proc_release   = release_kcore,
 616         .proc_lseek     = default_llseek,
 617 };
 618
 619 /* just remember that we have to update kcore */
 620 static int __meminit kcore_callback(struct notifier_block *self,
 621                                     unsigned long action, void *arg)
 622 {
 623         switch (action) {
 624         case MEM_ONLINE:
 625         case MEM_OFFLINE:
 626                 kcore_need_update = 1;
 627                 break;
 628         }
 629         return NOTIFY_OK;
 630 }
 631
 632
 633 static struct kcore_list kcore_vmalloc;
 634
 635 #ifdef CONFIG_ARCH_PROC_KCORE_TEXT
 636 static struct kcore_list kcore_text;
 637 /*
 638  * If defined, special segment is used for mapping kernel text instead of
 639  * direct-map area. We need to create special TEXT section.
 640  */
 641 static void __init proc_kcore_text_init(void)
 642 {
 643         kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
 644 }
 645 #else
 646 static void __init proc_kcore_text_init(void)
 647 {
 648 }
 649 #endif
 650
 651 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
 652 /*
 653  * MODULES_VADDR has no intersection with VMALLOC_ADDR.
 654  */
 655 static struct kcore_list kcore_modules;
 656 static void __init add_modules_range(void)
 657 {
 658         if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
 659                 kclist_add(&kcore_modules, (void *)MODULES_VADDR,
 660                         MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
 661         }
 662 }
 663 #else
 664 static void __init add_modules_range(void)
 665 {
 666 }
 667 #endif
 668
 669 static int __init proc_kcore_init(void)
 670 {
 671         proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &kcore_proc_ops);
 672         if (!proc_root_kcore) {
 673                 pr_err("couldn't create /proc/kcore\n");
 674                 return 0; /* Always returns 0. */
 675         }
 676         /* Store text area if it's special */
 677         proc_kcore_text_init();
 678         /* Store vmalloc area */
 679         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 680                 VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
 681         add_modules_range();
 682         /* Store direct-map area from physical memory map */
 683         kcore_update_ram();
 684         hotplug_memory_notifier(kcore_callback, DEFAULT_CALLBACK_PRI);
 685
 686         return 0;
 687 }
 688 fs_initcall(proc_kcore_init);