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/mm.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/kcore.h>
  16 #include <linux/user.h>
  17 #include <linux/capability.h>
  18 #include <linux/elf.h>
  19 #include <linux/elfcore.h>
  20 #include <linux/notifier.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/highmem.h>
  23 #include <linux/printk.h>
  24 #include <linux/bootmem.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 <asm/sections.h>
  34 #include "internal.h"
  35
  36 #define CORE_STR "CORE"
  37
  38 #ifndef ELF_CORE_EFLAGS
  39 #define ELF_CORE_EFLAGS 0
  40 #endif
  41
  42 static struct proc_dir_entry *proc_root_kcore;
  43
  44
  45 #ifndef kc_vaddr_to_offset
  46 #define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
  47 #endif
  48 #ifndef kc_offset_to_vaddr
  49 #define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
  50 #endif
  51
  52 /* An ELF note in memory */
  53 struct memelfnote
  54 {
  55         const char *name;
  56         int type;
  57         unsigned int datasz;
  58         void *data;
  59 };
  60
  61 static LIST_HEAD(kclist_head);
  62 static DEFINE_RWLOCK(kclist_lock);
  63 static int kcore_need_update = 1;
  64
  65 void
  66 kclist_add(struct kcore_list *new, void *addr, size_t size, int type)
  67 {
  68         new->addr = (unsigned long)addr;
  69         new->size = size;
  70         new->type = type;
  71
  72         write_lock(&kclist_lock);
  73         list_add_tail(&new->list, &kclist_head);
  74         write_unlock(&kclist_lock);
  75 }
  76
  77 static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
  78 {
  79         size_t try, size;
  80         struct kcore_list *m;
  81
  82         *nphdr = 1; /* PT_NOTE */
  83         size = 0;
  84
  85         list_for_each_entry(m, &kclist_head, list) {
  86                 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
  87                 if (try > size)
  88                         size = try;
  89                 *nphdr = *nphdr + 1;
  90         }
  91         *elf_buflen =   sizeof(struct elfhdr) +
  92                         (*nphdr + 2)*sizeof(struct elf_phdr) +
  93                         3 * ((sizeof(struct elf_note)) +
  94                              roundup(sizeof(CORE_STR), 4)) +
  95                         roundup(sizeof(struct elf_prstatus), 4) +
  96                         roundup(sizeof(struct elf_prpsinfo), 4) +
  97                         roundup(arch_task_struct_size, 4);
  98         *elf_buflen = PAGE_ALIGN(*elf_buflen);
  99         return size + *elf_buflen;
 100 }
 101
 102 static void free_kclist_ents(struct list_head *head)
 103 {
 104         struct kcore_list *tmp, *pos;
 105
 106         list_for_each_entry_safe(pos, tmp, head, list) {
 107                 list_del(&pos->list);
 108                 kfree(pos);
 109         }
 110 }
 111 /*
 112  * Replace all KCORE_RAM/KCORE_VMEMMAP information with passed list.
 113  */
 114 static void __kcore_update_ram(struct list_head *list)
 115 {
 116         int nphdr;
 117         size_t size;
 118         struct kcore_list *tmp, *pos;
 119         LIST_HEAD(garbage);
 120
 121         write_lock(&kclist_lock);
 122         if (kcore_need_update) {
 123                 list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
 124                         if (pos->type == KCORE_RAM
 125                                 || pos->type == KCORE_VMEMMAP)
 126                                 list_move(&pos->list, &garbage);
 127                 }
 128                 list_splice_tail(list, &kclist_head);
 129         } else
 130                 list_splice(list, &garbage);
 131         kcore_need_update = 0;
 132         proc_root_kcore->size = get_kcore_size(&nphdr, &size);
 133         write_unlock(&kclist_lock);
 134
 135         free_kclist_ents(&garbage);
 136 }
 137
 138
 139 #ifdef CONFIG_HIGHMEM
 140 /*
 141  * If no highmem, we can assume [0...max_low_pfn) continuous range of memory
 142  * because memory hole is not as big as !HIGHMEM case.
 143  * (HIGHMEM is special because part of memory is _invisible_ from the kernel.)
 144  */
 145 static int kcore_update_ram(void)
 146 {
 147         LIST_HEAD(head);
 148         struct kcore_list *ent;
 149         int ret = 0;
 150
 151         ent = kmalloc(sizeof(*ent), GFP_KERNEL);
 152         if (!ent)
 153                 return -ENOMEM;
 154         ent->addr = (unsigned long)__va(0);
 155         ent->size = max_low_pfn << PAGE_SHIFT;
 156         ent->type = KCORE_RAM;
 157         list_add(&ent->list, &head);
 158         __kcore_update_ram(&head);
 159         return ret;
 160 }
 161
 162 #else /* !CONFIG_HIGHMEM */
 163
 164 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 165 /* calculate vmemmap's address from given system ram pfn and register it */
 166 static int
 167 get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
 168 {
 169         unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
 170         unsigned long nr_pages = ent->size >> PAGE_SHIFT;
 171         unsigned long start, end;
 172         struct kcore_list *vmm, *tmp;
 173
 174
 175         start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
 176         end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
 177         end = PAGE_ALIGN(end);
 178         /* overlap check (because we have to align page */
 179         list_for_each_entry(tmp, head, list) {
 180                 if (tmp->type != KCORE_VMEMMAP)
 181                         continue;
 182                 if (start < tmp->addr + tmp->size)
 183                         if (end > tmp->addr)
 184                                 end = tmp->addr;
 185         }
 186         if (start < end) {
 187                 vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
 188                 if (!vmm)
 189                         return 0;
 190                 vmm->addr = start;
 191                 vmm->size = end - start;
 192                 vmm->type = KCORE_VMEMMAP;
 193                 list_add_tail(&vmm->list, head);
 194         }
 195         return 1;
 196
 197 }
 198 #else
 199 static int
 200 get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
 201 {
 202         return 1;
 203 }
 204
 205 #endif
 206
 207 static int
 208 kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
 209 {
 210         struct list_head *head = (struct list_head *)arg;
 211         struct kcore_list *ent;
 212         struct page *p;
 213
 214         if (!pfn_valid(pfn))
 215                 return 1;
 216
 217         p = pfn_to_page(pfn);
 218         if (!memmap_valid_within(pfn, p, page_zone(p)))
 219                 return 1;
 220
 221         ent = kmalloc(sizeof(*ent), GFP_KERNEL);
 222         if (!ent)
 223                 return -ENOMEM;
 224         ent->addr = (unsigned long)page_to_virt(p);
 225         ent->size = nr_pages << PAGE_SHIFT;
 226
 227         if (!virt_addr_valid(ent->addr))
 228                 goto free_out;
 229
 230         /* cut not-mapped area. ....from ppc-32 code. */
 231         if (ULONG_MAX - ent->addr < ent->size)
 232                 ent->size = ULONG_MAX - ent->addr;
 233
 234         /*
 235          * We've already checked virt_addr_valid so we know this address
 236          * is a valid pointer, therefore we can check against it to determine
 237          * if we need to trim
 238          */
 239         if (VMALLOC_START > ent->addr) {
 240                 if (VMALLOC_START - ent->addr < ent->size)
 241                         ent->size = VMALLOC_START - ent->addr;
 242         }
 243
 244         ent->type = KCORE_RAM;
 245         list_add_tail(&ent->list, head);
 246
 247         if (!get_sparsemem_vmemmap_info(ent, head)) {
 248                 list_del(&ent->list);
 249                 goto free_out;
 250         }
 251
 252         return 0;
 253 free_out:
 254         kfree(ent);
 255         return 1;
 256 }
 257
 258 static int kcore_update_ram(void)
 259 {
 260         int nid, ret;
 261         unsigned long end_pfn;
 262         LIST_HEAD(head);
 263
 264         /* Not inialized....update now */
 265         /* find out "max pfn" */
 266         end_pfn = 0;
 267         for_each_node_state(nid, N_MEMORY) {
 268                 unsigned long node_end;
 269                 node_end = node_end_pfn(nid);
 270                 if (end_pfn < node_end)
 271                         end_pfn = node_end;
 272         }
 273         /* scan 0 to max_pfn */
 274         ret = walk_system_ram_range(0, end_pfn, &head, kclist_add_private);
 275         if (ret) {
 276                 free_kclist_ents(&head);
 277                 return -ENOMEM;
 278         }
 279         __kcore_update_ram(&head);
 280         return ret;
 281 }
 282 #endif /* CONFIG_HIGHMEM */
 283
 284 /*****************************************************************************/
 285 /*
 286  * determine size of ELF note
 287  */
 288 static int notesize(struct memelfnote *en)
 289 {
 290         int sz;
 291
 292         sz = sizeof(struct elf_note);
 293         sz += roundup((strlen(en->name) + 1), 4);
 294         sz += roundup(en->datasz, 4);
 295
 296         return sz;
 297 } /* end notesize() */
 298
 299 /*****************************************************************************/
 300 /*
 301  * store a note in the header buffer
 302  */
 303 static char *storenote(struct memelfnote *men, char *bufp)
 304 {
 305         struct elf_note en;
 306
 307 #define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
 308
 309         en.n_namesz = strlen(men->name) + 1;
 310         en.n_descsz = men->datasz;
 311         en.n_type = men->type;
 312
 313         DUMP_WRITE(&en, sizeof(en));
 314         DUMP_WRITE(men->name, en.n_namesz);
 315
 316         /* XXX - cast from long long to long to avoid need for libgcc.a */
 317         bufp = (char*) roundup((unsigned long)bufp,4);
 318         DUMP_WRITE(men->data, men->datasz);
 319         bufp = (char*) roundup((unsigned long)bufp,4);
 320
 321 #undef DUMP_WRITE
 322
 323         return bufp;
 324 } /* end storenote() */
 325
 326 /*
 327  * store an ELF coredump header in the supplied buffer
 328  * nphdr is the number of elf_phdr to insert
 329  */
 330 static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
 331 {
 332         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
 333         struct elf_prpsinfo prpsinfo;   /* NT_PRPSINFO */
 334         struct elf_phdr *nhdr, *phdr;
 335         struct elfhdr *elf;
 336         struct memelfnote notes[3];
 337         off_t offset = 0;
 338         struct kcore_list *m;
 339
 340         /* setup ELF header */
 341         elf = (struct elfhdr *) bufp;
 342         bufp += sizeof(struct elfhdr);
 343         offset += sizeof(struct elfhdr);
 344         memcpy(elf->e_ident, ELFMAG, SELFMAG);
 345         elf->e_ident[EI_CLASS]  = ELF_CLASS;
 346         elf->e_ident[EI_DATA]   = ELF_DATA;
 347         elf->e_ident[EI_VERSION]= EV_CURRENT;
 348         elf->e_ident[EI_OSABI] = ELF_OSABI;
 349         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
 350         elf->e_type     = ET_CORE;
 351         elf->e_machine  = ELF_ARCH;
 352         elf->e_version  = EV_CURRENT;
 353         elf->e_entry    = 0;
 354         elf->e_phoff    = sizeof(struct elfhdr);
 355         elf->e_shoff    = 0;
 356         elf->e_flags    = ELF_CORE_EFLAGS;
 357         elf->e_ehsize   = sizeof(struct elfhdr);
 358         elf->e_phentsize= sizeof(struct elf_phdr);
 359         elf->e_phnum    = nphdr;
 360         elf->e_shentsize= 0;
 361         elf->e_shnum    = 0;
 362         elf->e_shstrndx = 0;
 363
 364         /* setup ELF PT_NOTE program header */
 365         nhdr = (struct elf_phdr *) bufp;
 366         bufp += sizeof(struct elf_phdr);
 367         offset += sizeof(struct elf_phdr);
 368         nhdr->p_type    = PT_NOTE;
 369         nhdr->p_offset  = 0;
 370         nhdr->p_vaddr   = 0;
 371         nhdr->p_paddr   = 0;
 372         nhdr->p_filesz  = 0;
 373         nhdr->p_memsz   = 0;
 374         nhdr->p_flags   = 0;
 375         nhdr->p_align   = 0;
 376
 377         /* setup ELF PT_LOAD program header for every area */
 378         list_for_each_entry(m, &kclist_head, list) {
 379                 phdr = (struct elf_phdr *) bufp;
 380                 bufp += sizeof(struct elf_phdr);
 381                 offset += sizeof(struct elf_phdr);
 382
 383                 phdr->p_type    = PT_LOAD;
 384                 phdr->p_flags   = PF_R|PF_W|PF_X;
 385                 phdr->p_offset  = kc_vaddr_to_offset(m->addr) + dataoff;
 386                 phdr->p_vaddr   = (size_t)m->addr;
 387                 if (m->type == KCORE_RAM)
 388                         phdr->p_paddr   = __pa(m->addr);
 389                 else if (m->type == KCORE_TEXT)
 390                         phdr->p_paddr   = __pa_symbol(m->addr);
 391                 else
 392                         phdr->p_paddr   = (elf_addr_t)-1;
 393                 phdr->p_filesz  = phdr->p_memsz = m->size;
 394                 phdr->p_align   = PAGE_SIZE;
 395         }
 396
 397         /*
 398          * Set up the notes in similar form to SVR4 core dumps made
 399          * with info from their /proc.
 400          */
 401         nhdr->p_offset  = offset;
 402
 403         /* set up the process status */
 404         notes[0].name = CORE_STR;
 405         notes[0].type = NT_PRSTATUS;
 406         notes[0].datasz = sizeof(struct elf_prstatus);
 407         notes[0].data = &prstatus;
 408
 409         memset(&prstatus, 0, sizeof(struct elf_prstatus));
 410
 411         nhdr->p_filesz  = notesize(&notes[0]);
 412         bufp = storenote(&notes[0], bufp);
 413
 414         /* set up the process info */
 415         notes[1].name   = CORE_STR;
 416         notes[1].type   = NT_PRPSINFO;
 417         notes[1].datasz = sizeof(struct elf_prpsinfo);
 418         notes[1].data   = &prpsinfo;
 419
 420         memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
 421         prpsinfo.pr_state       = 0;
 422         prpsinfo.pr_sname       = 'R';
 423         prpsinfo.pr_zomb        = 0;
 424
 425         strcpy(prpsinfo.pr_fname, "vmlinux");
 426         strlcpy(prpsinfo.pr_psargs, saved_command_line, sizeof(prpsinfo.pr_psargs));
 427
 428         nhdr->p_filesz  += notesize(&notes[1]);
 429         bufp = storenote(&notes[1], bufp);
 430
 431         /* set up the task structure */
 432         notes[2].name   = CORE_STR;
 433         notes[2].type   = NT_TASKSTRUCT;
 434         notes[2].datasz = arch_task_struct_size;
 435         notes[2].data   = current;
 436
 437         nhdr->p_filesz  += notesize(&notes[2]);
 438         bufp = storenote(&notes[2], bufp);
 439
 440 } /* end elf_kcore_store_hdr() */
 441
 442 /*****************************************************************************/
 443 /*
 444  * read from the ELF header and then kernel memory
 445  */
 446 static ssize_t
 447 read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
 448 {
 449         char *buf = file->private_data;
 450         ssize_t acc = 0;
 451         size_t size, tsz;
 452         size_t elf_buflen;
 453         int nphdr;
 454         unsigned long start;
 455
 456         read_lock(&kclist_lock);
 457         size = get_kcore_size(&nphdr, &elf_buflen);
 458
 459         if (buflen == 0 || *fpos >= size) {
 460                 read_unlock(&kclist_lock);
 461                 return 0;
 462         }
 463
 464         /* trim buflen to not go beyond EOF */
 465         if (buflen > size - *fpos)
 466                 buflen = size - *fpos;
 467
 468         /* construct an ELF core header if we'll need some of it */
 469         if (*fpos < elf_buflen) {
 470                 char * elf_buf;
 471
 472                 tsz = elf_buflen - *fpos;
 473                 if (buflen < tsz)
 474                         tsz = buflen;
 475                 elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
 476                 if (!elf_buf) {
 477                         read_unlock(&kclist_lock);
 478                         return -ENOMEM;
 479                 }
 480                 elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
 481                 read_unlock(&kclist_lock);
 482                 if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
 483                         kfree(elf_buf);
 484                         return -EFAULT;
 485                 }
 486                 kfree(elf_buf);
 487                 buflen -= tsz;
 488                 *fpos += tsz;
 489                 buffer += tsz;
 490                 acc += tsz;
 491
 492                 /* leave now if filled buffer already */
 493                 if (buflen == 0)
 494                         return acc;
 495         } else
 496                 read_unlock(&kclist_lock);
 497
 498         /*
 499          * Check to see if our file offset matches with any of
 500          * the addresses in the elf_phdr on our list.
 501          */
 502         start = kc_offset_to_vaddr(*fpos - elf_buflen);
 503         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 504                 tsz = buflen;
 505
 506         while (buflen) {
 507                 struct kcore_list *m;
 508
 509                 read_lock(&kclist_lock);
 510                 list_for_each_entry(m, &kclist_head, list) {
 511                         if (start >= m->addr && start < (m->addr+m->size))
 512                                 break;
 513                 }
 514                 read_unlock(&kclist_lock);
 515
 516                 if (&m->list == &kclist_head) {
 517                         if (clear_user(buffer, tsz))
 518                                 return -EFAULT;
 519                 } else if (m->type == KCORE_VMALLOC) {
 520                         vread(buf, (char *)start, tsz);
 521                         /* we have to zero-fill user buffer even if no read */
 522                         if (copy_to_user(buffer, buf, tsz))
 523                                 return -EFAULT;
 524                 } else if (m->type == KCORE_USER) {
 525                         /* User page is handled prior to normal kernel page: */
 526                         if (copy_to_user(buffer, (char *)start, tsz))
 527                                 return -EFAULT;
 528                 } else {
 529                         if (kern_addr_valid(start)) {
 530                                 /*
 531                                  * Using bounce buffer to bypass the
 532                                  * hardened user copy kernel text checks.
 533                                  */
 534                                 if (probe_kernel_read(buf, (void *) start, tsz)) {
 535                                         if (clear_user(buffer, tsz))
 536                                                 return -EFAULT;
 537                                 } else {
 538                                         if (copy_to_user(buffer, buf, tsz))
 539                                                 return -EFAULT;
 540                                 }
 541                         } else {
 542                                 if (clear_user(buffer, tsz))
 543                                         return -EFAULT;
 544                         }
 545                 }
 546                 buflen -= tsz;
 547                 *fpos += tsz;
 548                 buffer += tsz;
 549                 acc += tsz;
 550                 start += tsz;
 551                 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
 552         }
 553
 554         return acc;
 555 }
 556
 557
 558 static int open_kcore(struct inode *inode, struct file *filp)
 559 {
 560         if (!capable(CAP_SYS_RAWIO))
 561                 return -EPERM;
 562
 563         filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
 564         if (!filp->private_data)
 565                 return -ENOMEM;
 566
 567         if (kcore_need_update)
 568                 kcore_update_ram();
 569         if (i_size_read(inode) != proc_root_kcore->size) {
 570                 inode_lock(inode);
 571                 i_size_write(inode, proc_root_kcore->size);
 572                 inode_unlock(inode);
 573         }
 574         return 0;
 575 }
 576
 577 static int release_kcore(struct inode *inode, struct file *file)
 578 {
 579         kfree(file->private_data);
 580         return 0;
 581 }
 582
 583 static const struct file_operations proc_kcore_operations = {
 584         .read           = read_kcore,
 585         .open           = open_kcore,
 586         .release        = release_kcore,
 587         .llseek         = default_llseek,
 588 };
 589
 590 /* just remember that we have to update kcore */
 591 static int __meminit kcore_callback(struct notifier_block *self,
 592                                     unsigned long action, void *arg)
 593 {
 594         switch (action) {
 595         case MEM_ONLINE:
 596         case MEM_OFFLINE:
 597                 write_lock(&kclist_lock);
 598                 kcore_need_update = 1;
 599                 write_unlock(&kclist_lock);
 600         }
 601         return NOTIFY_OK;
 602 }
 603
 604 static struct notifier_block kcore_callback_nb __meminitdata = {
 605         .notifier_call = kcore_callback,
 606         .priority = 0,
 607 };
 608
 609 static struct kcore_list kcore_vmalloc;
 610
 611 #ifdef CONFIG_ARCH_PROC_KCORE_TEXT
 612 static struct kcore_list kcore_text;
 613 /*
 614  * If defined, special segment is used for mapping kernel text instead of
 615  * direct-map area. We need to create special TEXT section.
 616  */
 617 static void __init proc_kcore_text_init(void)
 618 {
 619         kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
 620 }
 621 #else
 622 static void __init proc_kcore_text_init(void)
 623 {
 624 }
 625 #endif
 626
 627 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
 628 /*
 629  * MODULES_VADDR has no intersection with VMALLOC_ADDR.
 630  */
 631 struct kcore_list kcore_modules;
 632 static void __init add_modules_range(void)
 633 {
 634         if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
 635                 kclist_add(&kcore_modules, (void *)MODULES_VADDR,
 636                         MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
 637         }
 638 }
 639 #else
 640 static void __init add_modules_range(void)
 641 {
 642 }
 643 #endif
 644
 645 static int __init proc_kcore_init(void)
 646 {
 647         proc_root_kcore = proc_create("kcore", S_IRUSR, NULL,
 648                                       &proc_kcore_operations);
 649         if (!proc_root_kcore) {
 650                 pr_err("couldn't create /proc/kcore\n");
 651                 return 0; /* Always returns 0. */
 652         }
 653         /* Store text area if it's special */
 654         proc_kcore_text_init();
 655         /* Store vmalloc area */
 656         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 657                 VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
 658         add_modules_range();
 659         /* Store direct-map area from physical memory map */
 660         kcore_update_ram();
 661         register_hotmemory_notifier(&kcore_callback_nb);
 662
 663         return 0;
 664 }
 665 fs_initcall(proc_kcore_init);