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 <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/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/uio.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 read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 311 {
 312         loff_t *fpos = &iocb->ki_pos;
 313         size_t phdrs_offset, notes_offset, data_offset;
 314         size_t page_offline_frozen = 1;
 315         size_t phdrs_len, notes_len;
 316         struct kcore_list *m;
 317         size_t tsz;
 318         int nphdr;
 319         unsigned long start;
 320         size_t buflen = iov_iter_count(iter);
 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_iter((char *)&ehdr + *fpos, tsz, iter) != tsz) {
 360                         ret = -EFAULT;
 361                         goto out;
 362                 }
 363
 364                 buflen -= tsz;
 365                 *fpos += tsz;
 366         }
 367
 368         /* ELF program headers. */
 369         if (buflen && *fpos < phdrs_offset + phdrs_len) {
 370                 struct elf_phdr *phdrs, *phdr;
 371
 372                 phdrs = kzalloc(phdrs_len, GFP_KERNEL);
 373                 if (!phdrs) {
 374                         ret = -ENOMEM;
 375                         goto out;
 376                 }
 377
 378                 phdrs[0].p_type = PT_NOTE;
 379                 phdrs[0].p_offset = notes_offset;
 380                 phdrs[0].p_filesz = notes_len;
 381
 382                 phdr = &phdrs[1];
 383                 list_for_each_entry(m, &kclist_head, list) {
 384                         phdr->p_type = PT_LOAD;
 385                         phdr->p_flags = PF_R | PF_W | PF_X;
 386                         phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;
 387                         phdr->p_vaddr = (size_t)m->addr;
 388                         if (m->type == KCORE_RAM)
 389                                 phdr->p_paddr = __pa(m->addr);
 390                         else if (m->type == KCORE_TEXT)
 391                                 phdr->p_paddr = __pa_symbol(m->addr);
 392                         else
 393                                 phdr->p_paddr = (elf_addr_t)-1;
 394                         phdr->p_filesz = phdr->p_memsz = m->size;
 395                         phdr->p_align = PAGE_SIZE;
 396                         phdr++;
 397                 }
 398
 399                 tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos);
 400                 if (copy_to_iter((char *)phdrs + *fpos - phdrs_offset, tsz,
 401                                  iter) != tsz) {
 402                         kfree(phdrs);
 403                         ret = -EFAULT;
 404                         goto out;
 405                 }
 406                 kfree(phdrs);
 407
 408                 buflen -= tsz;
 409                 *fpos += tsz;
 410         }
 411
 412         /* ELF note segment. */
 413         if (buflen && *fpos < notes_offset + notes_len) {
 414                 struct elf_prstatus prstatus = {};
 415                 struct elf_prpsinfo prpsinfo = {
 416                         .pr_sname = 'R',
 417                         .pr_fname = "vmlinux",
 418                 };
 419                 char *notes;
 420                 size_t i = 0;
 421
 422                 strlcpy(prpsinfo.pr_psargs, saved_command_line,
 423                         sizeof(prpsinfo.pr_psargs));
 424
 425                 notes = kzalloc(notes_len, GFP_KERNEL);
 426                 if (!notes) {
 427                         ret = -ENOMEM;
 428                         goto out;
 429                 }
 430
 431                 append_kcore_note(notes, &i, CORE_STR, NT_PRSTATUS, &prstatus,
 432                                   sizeof(prstatus));
 433                 append_kcore_note(notes, &i, CORE_STR, NT_PRPSINFO, &prpsinfo,
 434                                   sizeof(prpsinfo));
 435                 append_kcore_note(notes, &i, CORE_STR, NT_TASKSTRUCT, current,
 436                                   arch_task_struct_size);
 437                 /*
 438                  * vmcoreinfo_size is mostly constant after init time, but it
 439                  * can be changed by crash_save_vmcoreinfo(). Racing here with a
 440                  * panic on another CPU before the machine goes down is insanely
 441                  * unlikely, but it's better to not leave potential buffer
 442                  * overflows lying around, regardless.
 443                  */
 444                 append_kcore_note(notes, &i, VMCOREINFO_NOTE_NAME, 0,
 445                                   vmcoreinfo_data,
 446                                   min(vmcoreinfo_size, notes_len - i));
 447
 448                 tsz = min_t(size_t, buflen, notes_offset + notes_len - *fpos);
 449                 if (copy_to_iter(notes + *fpos - notes_offset, tsz, iter) != tsz) {
 450                         kfree(notes);
 451                         ret = -EFAULT;
 452                         goto out;
 453                 }
 454                 kfree(notes);
 455
 456                 buflen -= tsz;
 457                 *fpos += tsz;
 458         }
 459
 460         /*
 461          * Check to see if our file offset matches with any of
 462          * the addresses in the elf_phdr on our list.
 463          */
 464         start = kc_offset_to_vaddr(*fpos - data_offset);
 465         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 466                 tsz = buflen;
 467
 468         m = NULL;
 469         while (buflen) {
 470                 struct page *page;
 471                 unsigned long pfn;
 472
 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                         struct kcore_list *iter;
 479
 480                         m = NULL;
 481                         list_for_each_entry(iter, &kclist_head, list) {
 482                                 if (start >= iter->addr &&
 483                                     start < iter->addr + iter->size) {
 484                                         m = iter;
 485                                         break;
 486                                 }
 487                         }
 488                 }
 489
 490                 if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) {
 491                         page_offline_thaw();
 492                         cond_resched();
 493                         page_offline_freeze();
 494                 }
 495
 496                 if (!m) {
 497                         if (iov_iter_zero(tsz, iter) != tsz) {
 498                                 ret = -EFAULT;
 499                                 goto out;
 500                         }
 501                         goto skip;
 502                 }
 503
 504                 switch (m->type) {
 505                 case KCORE_VMALLOC:
 506                 {
 507                         const char *src = (char *)start;
 508                         size_t read = 0, left = tsz;
 509
 510                         /*
 511                          * vmalloc uses spinlocks, so we optimistically try to
 512                          * read memory. If this fails, fault pages in and try
 513                          * again until we are done.
 514                          */
 515                         while (true) {
 516                                 read += vread_iter(iter, src, left);
 517                                 if (read == tsz)
 518                                         break;
 519
 520                                 src += read;
 521                                 left -= read;
 522
 523                                 if (fault_in_iov_iter_writeable(iter, left)) {
 524                                         ret = -EFAULT;
 525                                         goto out;
 526                                 }
 527                         }
 528                         break;
 529                 }
 530                 case KCORE_USER:
 531                         /* User page is handled prior to normal kernel page: */
 532                         if (copy_to_iter((char *)start, tsz, iter) != tsz) {
 533                                 ret = -EFAULT;
 534                                 goto out;
 535                         }
 536                         break;
 537                 case KCORE_RAM:
 538                         pfn = __pa(start) >> PAGE_SHIFT;
 539                         page = pfn_to_online_page(pfn);
 540
 541                         /*
 542                          * Don't read offline sections, logically offline pages
 543                          * (e.g., inflated in a balloon), hwpoisoned pages,
 544                          * and explicitly excluded physical ranges.
 545                          */
 546                         if (!page || PageOffline(page) ||
 547                             is_page_hwpoison(page) || !pfn_is_ram(pfn)) {
 548                                 if (iov_iter_zero(tsz, iter) != tsz) {
 549                                         ret = -EFAULT;
 550                                         goto out;
 551                                 }
 552                                 break;
 553                         }
 554                         fallthrough;
 555                 case KCORE_VMEMMAP:
 556                 case KCORE_TEXT:
 557                         /*
 558                          * We use _copy_to_iter() to bypass usermode hardening
 559                          * which would otherwise prevent this operation.
 560                          */
 561                         if (_copy_to_iter((char *)start, tsz, iter) != tsz) {
 562                                 ret = -EFAULT;
 563                                 goto out;
 564                         }
 565                         break;
 566                 default:
 567                         pr_warn_once("Unhandled KCORE type: %d\n", m->type);
 568                         if (iov_iter_zero(tsz, iter) != tsz) {
 569                                 ret = -EFAULT;
 570                                 goto out;
 571                         }
 572                 }
 573 skip:
 574                 buflen -= tsz;
 575                 *fpos += tsz;
 576                 start += tsz;
 577                 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
 578         }
 579
 580 out:
 581         page_offline_thaw();
 582         up_read(&kclist_lock);
 583         if (ret)
 584                 return ret;
 585         return orig_buflen - buflen;
 586 }
 587
 588 static int open_kcore(struct inode *inode, struct file *filp)
 589 {
 590         int ret = security_locked_down(LOCKDOWN_KCORE);
 591
 592         if (!capable(CAP_SYS_RAWIO))
 593                 return -EPERM;
 594
 595         if (ret)
 596                 return ret;
 597
 598         if (kcore_need_update)
 599                 kcore_update_ram();
 600         if (i_size_read(inode) != proc_root_kcore->size) {
 601                 inode_lock(inode);
 602                 i_size_write(inode, proc_root_kcore->size);
 603                 inode_unlock(inode);
 604         }
 605         return 0;
 606 }
 607
 608 static const struct proc_ops kcore_proc_ops = {
 609         .proc_read_iter = read_kcore_iter,
 610         .proc_open      = open_kcore,
 611         .proc_lseek     = default_llseek,
 612 };
 613
 614 /* just remember that we have to update kcore */
 615 static int __meminit kcore_callback(struct notifier_block *self,
 616                                     unsigned long action, void *arg)
 617 {
 618         switch (action) {
 619         case MEM_ONLINE:
 620         case MEM_OFFLINE:
 621                 kcore_need_update = 1;
 622                 break;
 623         }
 624         return NOTIFY_OK;
 625 }
 626
 627
 628 static struct kcore_list kcore_vmalloc;
 629
 630 #ifdef CONFIG_ARCH_PROC_KCORE_TEXT
 631 static struct kcore_list kcore_text;
 632 /*
 633  * If defined, special segment is used for mapping kernel text instead of
 634  * direct-map area. We need to create special TEXT section.
 635  */
 636 static void __init proc_kcore_text_init(void)
 637 {
 638         kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
 639 }
 640 #else
 641 static void __init proc_kcore_text_init(void)
 642 {
 643 }
 644 #endif
 645
 646 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
 647 /*
 648  * MODULES_VADDR has no intersection with VMALLOC_ADDR.
 649  */
 650 static struct kcore_list kcore_modules;
 651 static void __init add_modules_range(void)
 652 {
 653         if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
 654                 kclist_add(&kcore_modules, (void *)MODULES_VADDR,
 655                         MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
 656         }
 657 }
 658 #else
 659 static void __init add_modules_range(void)
 660 {
 661 }
 662 #endif
 663
 664 static int __init proc_kcore_init(void)
 665 {
 666         proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &kcore_proc_ops);
 667         if (!proc_root_kcore) {
 668                 pr_err("couldn't create /proc/kcore\n");
 669                 return 0; /* Always returns 0. */
 670         }
 671         /* Store text area if it's special */
 672         proc_kcore_text_init();
 673         /* Store vmalloc area */
 674         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 675                 VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
 676         add_modules_range();
 677         /* Store direct-map area from physical memory map */
 678         kcore_update_ram();
 679         hotplug_memory_notifier(kcore_callback, DEFAULT_CALLBACK_PRI);
 680
 681         return 0;
 682 }
 683 fs_initcall(proc_kcore_init);