root/fs/proc/kcore.c

DEFINITIONS

1. register_mem_pfn_is_ram
2. pfn_is_ram
3. kclist_add
4. get_kcore_size
5. kcore_ram_list
6. get_sparsemem_vmemmap_info
7. get_sparsemem_vmemmap_info
8. kclist_add_private
9. kcore_ram_list
10. kcore_update_ram
11. append_kcore_note
12. read_kcore
13. open_kcore
14. release_kcore
15. kcore_callback
16. proc_kcore_text_init
17. proc_kcore_text_init
18. add_modules_range
19. add_modules_range
20. proc_kcore_init

   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 <jeremy@sw.oz.au>
   7  *      ELF version written by David Howells <David.Howells@nexor.co.uk>
   8  *      Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
   9  *      Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
  10  *      Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
  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/notifier.h>
  22 #include <linux/vmalloc.h>
  23 #include <linux/highmem.h>
  24 #include <linux/printk.h>
  25 #include <linux/memblock.h>
  26 #include <linux/init.h>
  27 #include <linux/slab.h>
  28 #include <linux/uaccess.h>
  29 #include <asm/io.h>
  30 #include <linux/list.h>
  31 #include <linux/ioport.h>
  32 #include <linux/memory.h>
  33 #include <linux/sched/task.h>
  34 #include <linux/security.h>
  35 #include <asm/sections.h>
  36 #include "internal.h"
  37 
  38 #define CORE_STR "CORE"
  39 
  40 #ifndef ELF_CORE_EFLAGS
  41 #define ELF_CORE_EFLAGS 0
  42 #endif
  43 
  44 static struct proc_dir_entry *proc_root_kcore;
  45 
  46 
  47 #ifndef kc_vaddr_to_offset
  48 #define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
  49 #endif
  50 #ifndef kc_offset_to_vaddr
  51 #define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
  52 #endif
  53 
  54 static LIST_HEAD(kclist_head);
  55 static DECLARE_RWSEM(kclist_lock);
  56 static int kcore_need_update = 1;
  57 
  58 /*
  59  * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  60  * Same as oldmem_pfn_is_ram in vmcore
  61  */
  62 static int (*mem_pfn_is_ram)(unsigned long pfn);
  63 
  64 int __init register_mem_pfn_is_ram(int (*fn)(unsigned long pfn))
  65 {
  66         if (mem_pfn_is_ram)
  67                 return -EBUSY;
  68         mem_pfn_is_ram = fn;
  69         return 0;
  70 }
  71 
  72 static int pfn_is_ram(unsigned long pfn)
  73 {
  74         if (mem_pfn_is_ram)
  75                 return mem_pfn_is_ram(pfn);
  76         else
  77                 return 1;
  78 }
  79 
  80 /* This doesn't grab kclist_lock, so it should only be used at init time. */
  81 void __init kclist_add(struct kcore_list *new, void *addr, size_t size,
  82                        int type)
  83 {
  84         new->addr = (unsigned long)addr;
  85         new->size = size;
  86         new->type = type;
  87 
  88         list_add_tail(&new->list, &kclist_head);
  89 }
  90 
  91 static size_t get_kcore_size(int *nphdr, size_t *phdrs_len, size_t *notes_len,
  92                              size_t *data_offset)
  93 {
  94         size_t try, size;
  95         struct kcore_list *m;
  96 
  97         *nphdr = 1; /* PT_NOTE */
  98         size = 0;
  99 
 100         list_for_each_entry(m, &kclist_head, list) {
 101                 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
 102                 if (try > size)
 103                         size = try;
 104                 *nphdr = *nphdr + 1;
 105         }
 106 
 107         *phdrs_len = *nphdr * sizeof(struct elf_phdr);
 108         *notes_len = (4 * sizeof(struct elf_note) +
 109                       3 * ALIGN(sizeof(CORE_STR), 4) +
 110                       VMCOREINFO_NOTE_NAME_BYTES +
 111                       ALIGN(sizeof(struct elf_prstatus), 4) +
 112                       ALIGN(sizeof(struct elf_prpsinfo), 4) +
 113                       ALIGN(arch_task_struct_size, 4) +
 114                       ALIGN(vmcoreinfo_size, 4));
 115         *data_offset = PAGE_ALIGN(sizeof(struct elfhdr) + *phdrs_len +
 116                                   *notes_len);
 117         return *data_offset + size;
 118 }
 119 
 120 #ifdef CONFIG_HIGHMEM
 121 /*
 122  * If no highmem, we can assume [0...max_low_pfn) continuous range of memory
 123  * because memory hole is not as big as !HIGHMEM case.
 124  * (HIGHMEM is special because part of memory is _invisible_ from the kernel.)
 125  */
 126 static int kcore_ram_list(struct list_head *head)
 127 {
 128         struct kcore_list *ent;
 129 
 130         ent = kmalloc(sizeof(*ent), GFP_KERNEL);
 131         if (!ent)
 132                 return -ENOMEM;
 133         ent->addr = (unsigned long)__va(0);
 134         ent->size = max_low_pfn << PAGE_SHIFT;
 135         ent->type = KCORE_RAM;
 136         list_add(&ent->list, head);
 137         return 0;
 138 }
 139 
 140 #else /* !CONFIG_HIGHMEM */
 141 
 142 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 143 /* calculate vmemmap's address from given system ram pfn and register it */
 144 static int
 145 get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
 146 {
 147         unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
 148         unsigned long nr_pages = ent->size >> PAGE_SHIFT;
 149         unsigned long start, end;
 150         struct kcore_list *vmm, *tmp;
 151 
 152 
 153         start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
 154         end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
 155         end = PAGE_ALIGN(end);
 156         /* overlap check (because we have to align page */
 157         list_for_each_entry(tmp, head, list) {
 158                 if (tmp->type != KCORE_VMEMMAP)
 159                         continue;
 160                 if (start < tmp->addr + tmp->size)
 161                         if (end > tmp->addr)
 162                                 end = tmp->addr;
 163         }
 164         if (start < end) {
 165                 vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
 166                 if (!vmm)
 167                         return 0;
 168                 vmm->addr = start;
 169                 vmm->size = end - start;
 170                 vmm->type = KCORE_VMEMMAP;
 171                 list_add_tail(&vmm->list, head);
 172         }
 173         return 1;
 174 
 175 }
 176 #else
 177 static int
 178 get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
 179 {
 180         return 1;
 181 }
 182 
 183 #endif
 184 
 185 static int
 186 kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
 187 {
 188         struct list_head *head = (struct list_head *)arg;
 189         struct kcore_list *ent;
 190         struct page *p;
 191 
 192         if (!pfn_valid(pfn))
 193                 return 1;
 194 
 195         p = pfn_to_page(pfn);
 196         if (!memmap_valid_within(pfn, p, page_zone(p)))
 197                 return 1;
 198 
 199         ent = kmalloc(sizeof(*ent), GFP_KERNEL);
 200         if (!ent)
 201                 return -ENOMEM;
 202         ent->addr = (unsigned long)page_to_virt(p);
 203         ent->size = nr_pages << PAGE_SHIFT;
 204 
 205         if (!virt_addr_valid(ent->addr))
 206                 goto free_out;
 207 
 208         /* cut not-mapped area. ....from ppc-32 code. */
 209         if (ULONG_MAX - ent->addr < ent->size)
 210                 ent->size = ULONG_MAX - ent->addr;
 211 
 212         /*
 213          * We've already checked virt_addr_valid so we know this address
 214          * is a valid pointer, therefore we can check against it to determine
 215          * if we need to trim
 216          */
 217         if (VMALLOC_START > ent->addr) {
 218                 if (VMALLOC_START - ent->addr < ent->size)
 219                         ent->size = VMALLOC_START - ent->addr;
 220         }
 221 
 222         ent->type = KCORE_RAM;
 223         list_add_tail(&ent->list, head);
 224 
 225         if (!get_sparsemem_vmemmap_info(ent, head)) {
 226                 list_del(&ent->list);
 227                 goto free_out;
 228         }
 229 
 230         return 0;
 231 free_out:
 232         kfree(ent);
 233         return 1;
 234 }
 235 
 236 static int kcore_ram_list(struct list_head *list)
 237 {
 238         int nid, ret;
 239         unsigned long end_pfn;
 240 
 241         /* Not inialized....update now */
 242         /* find out "max pfn" */
 243         end_pfn = 0;
 244         for_each_node_state(nid, N_MEMORY) {
 245                 unsigned long node_end;
 246                 node_end = node_end_pfn(nid);
 247                 if (end_pfn < node_end)
 248                         end_pfn = node_end;
 249         }
 250         /* scan 0 to max_pfn */
 251         ret = walk_system_ram_range(0, end_pfn, list, kclist_add_private);
 252         if (ret)
 253                 return -ENOMEM;
 254         return 0;
 255 }
 256 #endif /* CONFIG_HIGHMEM */
 257 
 258 static int kcore_update_ram(void)
 259 {
 260         LIST_HEAD(list);
 261         LIST_HEAD(garbage);
 262         int nphdr;
 263         size_t phdrs_len, notes_len, data_offset;
 264         struct kcore_list *tmp, *pos;
 265         int ret = 0;
 266 
 267         down_write(&kclist_lock);
 268         if (!xchg(&kcore_need_update, 0))
 269                 goto out;
 270 
 271         ret = kcore_ram_list(&list);
 272         if (ret) {
 273                 /* Couldn't get the RAM list, try again next time. */
 274                 WRITE_ONCE(kcore_need_update, 1);
 275                 list_splice_tail(&list, &garbage);
 276                 goto out;
 277         }
 278 
 279         list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
 280                 if (pos->type == KCORE_RAM || pos->type == KCORE_VMEMMAP)
 281                         list_move(&pos->list, &garbage);
 282         }
 283         list_splice_tail(&list, &kclist_head);
 284 
 285         proc_root_kcore->size = get_kcore_size(&nphdr, &phdrs_len, &notes_len,
 286                                                &data_offset);
 287 
 288 out:
 289         up_write(&kclist_lock);
 290         list_for_each_entry_safe(pos, tmp, &garbage, list) {
 291                 list_del(&pos->list);
 292                 kfree(pos);
 293         }
 294         return ret;
 295 }
 296 
 297 static void append_kcore_note(char *notes, size_t *i, const char *name,
 298                               unsigned int type, const void *desc,
 299                               size_t descsz)
 300 {
 301         struct elf_note *note = (struct elf_note *)&notes[*i];
 302 
 303         note->n_namesz = strlen(name) + 1;
 304         note->n_descsz = descsz;
 305         note->n_type = type;
 306         *i += sizeof(*note);
 307         memcpy(&notes[*i], name, note->n_namesz);
 308         *i = ALIGN(*i + note->n_namesz, 4);
 309         memcpy(&notes[*i], desc, descsz);
 310         *i = ALIGN(*i + descsz, 4);
 311 }
 312 
 313 static ssize_t
 314 read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
 315 {
 316         char *buf = file->private_data;
 317         size_t phdrs_offset, notes_offset, data_offset;
 318         size_t phdrs_len, notes_len;
 319         struct kcore_list *m;
 320         size_t tsz;
 321         int nphdr;
 322         unsigned long start;
 323         size_t orig_buflen = buflen;
 324         int ret = 0;
 325 
 326         down_read(&kclist_lock);
 327 
 328         get_kcore_size(&nphdr, &phdrs_len, &notes_len, &data_offset);
 329         phdrs_offset = sizeof(struct elfhdr);
 330         notes_offset = phdrs_offset + phdrs_len;
 331 
 332         /* ELF file header. */
 333         if (buflen && *fpos < sizeof(struct elfhdr)) {
 334                 struct elfhdr ehdr = {
 335                         .e_ident = {
 336                                 [EI_MAG0] = ELFMAG0,
 337                                 [EI_MAG1] = ELFMAG1,
 338                                 [EI_MAG2] = ELFMAG2,
 339                                 [EI_MAG3] = ELFMAG3,
 340                                 [EI_CLASS] = ELF_CLASS,
 341                                 [EI_DATA] = ELF_DATA,
 342                                 [EI_VERSION] = EV_CURRENT,
 343                                 [EI_OSABI] = ELF_OSABI,
 344                         },
 345                         .e_type = ET_CORE,
 346                         .e_machine = ELF_ARCH,
 347                         .e_version = EV_CURRENT,
 348                         .e_phoff = sizeof(struct elfhdr),
 349                         .e_flags = ELF_CORE_EFLAGS,
 350                         .e_ehsize = sizeof(struct elfhdr),
 351                         .e_phentsize = sizeof(struct elf_phdr),
 352                         .e_phnum = nphdr,
 353                 };
 354 
 355                 tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos);
 356                 if (copy_to_user(buffer, (char *)&ehdr + *fpos, tsz)) {
 357                         ret = -EFAULT;
 358                         goto out;
 359                 }
 360 
 361                 buffer += tsz;
 362                 buflen -= tsz;
 363                 *fpos += tsz;
 364         }
 365 
 366         /* ELF program headers. */
 367         if (buflen && *fpos < phdrs_offset + phdrs_len) {
 368                 struct elf_phdr *phdrs, *phdr;
 369 
 370                 phdrs = kzalloc(phdrs_len, GFP_KERNEL);
 371                 if (!phdrs) {
 372                         ret = -ENOMEM;
 373                         goto out;
 374                 }
 375 
 376                 phdrs[0].p_type = PT_NOTE;
 377                 phdrs[0].p_offset = notes_offset;
 378                 phdrs[0].p_filesz = notes_len;
 379 
 380                 phdr = &phdrs[1];
 381                 list_for_each_entry(m, &kclist_head, list) {
 382                         phdr->p_type = PT_LOAD;
 383                         phdr->p_flags = PF_R | PF_W | PF_X;
 384                         phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;
 385                         if (m->type == KCORE_REMAP)
 386                                 phdr->p_vaddr = (size_t)m->vaddr;
 387                         else
 388                                 phdr->p_vaddr = (size_t)m->addr;
 389                         if (m->type == KCORE_RAM || m->type == KCORE_REMAP)
 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                 /*
 474                  * If this is the first iteration or the address is not within
 475                  * the previous entry, search for a matching entry.
 476                  */
 477                 if (!m || start < m->addr || start >= m->addr + m->size) {
 478                         list_for_each_entry(m, &kclist_head, list) {
 479                                 if (start >= m->addr &&
 480                                     start < m->addr + m->size)
 481                                         break;
 482                         }
 483                 }
 484 
 485                 if (&m->list == &kclist_head) {
 486                         if (clear_user(buffer, tsz)) {
 487                                 ret = -EFAULT;
 488                                 goto out;
 489                         }
 490                         m = NULL;       /* skip the list anchor */
 491                 } else if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) {
 492                         if (clear_user(buffer, tsz)) {
 493                                 ret = -EFAULT;
 494                                 goto out;
 495                         }
 496                 } else if (m->type == KCORE_VMALLOC) {
 497                         vread(buf, (char *)start, tsz);
 498                         /* we have to zero-fill user buffer even if no read */
 499                         if (copy_to_user(buffer, buf, tsz)) {
 500                                 ret = -EFAULT;
 501                                 goto out;
 502                         }
 503                 } else if (m->type == KCORE_USER) {
 504                         /* User page is handled prior to normal kernel page: */
 505                         if (copy_to_user(buffer, (char *)start, tsz)) {
 506                                 ret = -EFAULT;
 507                                 goto out;
 508                         }
 509                 } else {
 510                         if (kern_addr_valid(start)) {
 511                                 /*
 512                                  * Using bounce buffer to bypass the
 513                                  * hardened user copy kernel text checks.
 514                                  */
 515                                 if (probe_kernel_read(buf, (void *) start, tsz)) {
 516                                         if (clear_user(buffer, tsz)) {
 517                                                 ret = -EFAULT;
 518                                                 goto out;
 519                                         }
 520                                 } else {
 521                                         if (copy_to_user(buffer, buf, tsz)) {
 522                                                 ret = -EFAULT;
 523                                                 goto out;
 524                                         }
 525                                 }
 526                         } else {
 527                                 if (clear_user(buffer, tsz)) {
 528                                         ret = -EFAULT;
 529                                         goto out;
 530                                 }
 531                         }
 532                 }
 533                 buflen -= tsz;
 534                 *fpos += tsz;
 535                 buffer += tsz;
 536                 start += tsz;
 537                 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
 538         }
 539 
 540 out:
 541         up_read(&kclist_lock);
 542         if (ret)
 543                 return ret;
 544         return orig_buflen - buflen;
 545 }
 546 
 547 static int open_kcore(struct inode *inode, struct file *filp)
 548 {
 549         int ret = security_locked_down(LOCKDOWN_KCORE);
 550 
 551         if (!capable(CAP_SYS_RAWIO))
 552                 return -EPERM;
 553 
 554         if (ret)
 555                 return ret;
 556 
 557         filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
 558         if (!filp->private_data)
 559                 return -ENOMEM;
 560 
 561         if (kcore_need_update)
 562                 kcore_update_ram();
 563         if (i_size_read(inode) != proc_root_kcore->size) {
 564                 inode_lock(inode);
 565                 i_size_write(inode, proc_root_kcore->size);
 566                 inode_unlock(inode);
 567         }
 568         return 0;
 569 }
 570 
 571 static int release_kcore(struct inode *inode, struct file *file)
 572 {
 573         kfree(file->private_data);
 574         return 0;
 575 }
 576 
 577 static const struct file_operations proc_kcore_operations = {
 578         .read           = read_kcore,
 579         .open           = open_kcore,
 580         .release        = release_kcore,
 581         .llseek         = default_llseek,
 582 };
 583 
 584 /* just remember that we have to update kcore */
 585 static int __meminit kcore_callback(struct notifier_block *self,
 586                                     unsigned long action, void *arg)
 587 {
 588         switch (action) {
 589         case MEM_ONLINE:
 590         case MEM_OFFLINE:
 591                 kcore_need_update = 1;
 592                 break;
 593         }
 594         return NOTIFY_OK;
 595 }
 596 
 597 static struct notifier_block kcore_callback_nb __meminitdata = {
 598         .notifier_call = kcore_callback,
 599         .priority = 0,
 600 };
 601 
 602 static struct kcore_list kcore_vmalloc;
 603 
 604 #ifdef CONFIG_ARCH_PROC_KCORE_TEXT
 605 static struct kcore_list kcore_text;
 606 /*
 607  * If defined, special segment is used for mapping kernel text instead of
 608  * direct-map area. We need to create special TEXT section.
 609  */
 610 static void __init proc_kcore_text_init(void)
 611 {
 612         kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
 613 }
 614 #else
 615 static void __init proc_kcore_text_init(void)
 616 {
 617 }
 618 #endif
 619 
 620 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
 621 /*
 622  * MODULES_VADDR has no intersection with VMALLOC_ADDR.
 623  */
 624 static struct kcore_list kcore_modules;
 625 static void __init add_modules_range(void)
 626 {
 627         if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
 628                 kclist_add(&kcore_modules, (void *)MODULES_VADDR,
 629                         MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
 630         }
 631 }
 632 #else
 633 static void __init add_modules_range(void)
 634 {
 635 }
 636 #endif
 637 
 638 static int __init proc_kcore_init(void)
 639 {
 640         proc_root_kcore = proc_create("kcore", S_IRUSR, NULL,
 641                                       &proc_kcore_operations);
 642         if (!proc_root_kcore) {
 643                 pr_err("couldn't create /proc/kcore\n");
 644                 return 0; /* Always returns 0. */
 645         }
 646         /* Store text area if it's special */
 647         proc_kcore_text_init();
 648         /* Store vmalloc area */
 649         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 650                 VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
 651         add_modules_range();
 652         /* Store direct-map area from physical memory map */
 653         kcore_update_ram();
 654         register_hotmemory_notifier(&kcore_callback_nb);
 655 
 656         return 0;
 657 }
 658 fs_initcall(proc_kcore_init);