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/vmcore_info.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((void *)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         struct file *file = iocb->ki_filp;
 313         char *buf = file->private_data;
 314         loff_t *fpos = &iocb->ki_pos;
 315         size_t phdrs_offset, notes_offset, data_offset;
 316         size_t page_offline_frozen = 1;
 317         size_t phdrs_len, notes_len;
 318         struct kcore_list *m;
 319         size_t tsz;
 320         int nphdr;
 321         unsigned long start;
 322         size_t buflen = iov_iter_count(iter);
 323         size_t orig_buflen = buflen;
 324         int ret = 0;
 325
 326         down_read(&kclist_lock);
 327         /*
 328          * Don't race against drivers that set PageOffline() and expect no
 329          * further page access.
 330          */
 331         page_offline_freeze();
 332
 333         get_kcore_size(&nphdr, &phdrs_len, &notes_len, &data_offset);
 334         phdrs_offset = sizeof(struct elfhdr);
 335         notes_offset = phdrs_offset + phdrs_len;
 336
 337         /* ELF file header. */
 338         if (buflen && *fpos < sizeof(struct elfhdr)) {
 339                 struct elfhdr ehdr = {
 340                         .e_ident = {
 341                                 [EI_MAG0] = ELFMAG0,
 342                                 [EI_MAG1] = ELFMAG1,
 343                                 [EI_MAG2] = ELFMAG2,
 344                                 [EI_MAG3] = ELFMAG3,
 345                                 [EI_CLASS] = ELF_CLASS,
 346                                 [EI_DATA] = ELF_DATA,
 347                                 [EI_VERSION] = EV_CURRENT,
 348                                 [EI_OSABI] = ELF_OSABI,
 349                         },
 350                         .e_type = ET_CORE,
 351                         .e_machine = ELF_ARCH,
 352                         .e_version = EV_CURRENT,
 353                         .e_phoff = sizeof(struct elfhdr),
 354                         .e_flags = ELF_CORE_EFLAGS,
 355                         .e_ehsize = sizeof(struct elfhdr),
 356                         .e_phentsize = sizeof(struct elf_phdr),
 357                         .e_phnum = nphdr,
 358                 };
 359
 360                 tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos);
 361                 if (copy_to_iter((char *)&ehdr + *fpos, tsz, iter) != tsz) {
 362                         ret = -EFAULT;
 363                         goto out;
 364                 }
 365
 366                 buflen -= tsz;
 367                 *fpos += tsz;
 368         }
 369
 370         /* ELF program headers. */
 371         if (buflen && *fpos < phdrs_offset + phdrs_len) {
 372                 struct elf_phdr *phdrs, *phdr;
 373
 374                 phdrs = kzalloc(phdrs_len, GFP_KERNEL);
 375                 if (!phdrs) {
 376                         ret = -ENOMEM;
 377                         goto out;
 378                 }
 379
 380                 phdrs[0].p_type = PT_NOTE;
 381                 phdrs[0].p_offset = notes_offset;
 382                 phdrs[0].p_filesz = notes_len;
 383
 384                 phdr = &phdrs[1];
 385                 list_for_each_entry(m, &kclist_head, list) {
 386                         phdr->p_type = PT_LOAD;
 387                         phdr->p_flags = PF_R | PF_W | PF_X;
 388                         phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;
 389                         phdr->p_vaddr = (size_t)m->addr;
 390                         if (m->type == KCORE_RAM)
 391                                 phdr->p_paddr = __pa(m->addr);
 392                         else if (m->type == KCORE_TEXT)
 393                                 phdr->p_paddr = __pa_symbol(m->addr);
 394                         else
 395                                 phdr->p_paddr = (elf_addr_t)-1;
 396                         phdr->p_filesz = phdr->p_memsz = m->size;
 397                         phdr->p_align = PAGE_SIZE;
 398                         phdr++;
 399                 }
 400
 401                 tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos);
 402                 if (copy_to_iter((char *)phdrs + *fpos - phdrs_offset, tsz,
 403                                  iter) != tsz) {
 404                         kfree(phdrs);
 405                         ret = -EFAULT;
 406                         goto out;
 407                 }
 408                 kfree(phdrs);
 409
 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                 strscpy(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_iter(notes + *fpos - notes_offset, tsz, iter) != tsz) {
 452                         kfree(notes);
 453                         ret = -EFAULT;
 454                         goto out;
 455                 }
 456                 kfree(notes);
 457
 458                 buflen -= tsz;
 459                 *fpos += tsz;
 460         }
 461
 462         /*
 463          * Check to see if our file offset matches with any of
 464          * the addresses in the elf_phdr on our list.
 465          */
 466         start = kc_offset_to_vaddr(*fpos - data_offset);
 467         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 468                 tsz = buflen;
 469
 470         m = NULL;
 471         while (buflen) {
 472                 struct page *page;
 473                 unsigned long pfn;
 474
 475                 /*
 476                  * If this is the first iteration or the address is not within
 477                  * the previous entry, search for a matching entry.
 478                  */
 479                 if (!m || start < m->addr || start >= m->addr + m->size) {
 480                         struct kcore_list *iter;
 481
 482                         m = NULL;
 483                         list_for_each_entry(iter, &kclist_head, list) {
 484                                 if (start >= iter->addr &&
 485                                     start < iter->addr + iter->size) {
 486                                         m = iter;
 487                                         break;
 488                                 }
 489                         }
 490                 }
 491
 492                 if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) {
 493                         page_offline_thaw();
 494                         cond_resched();
 495                         page_offline_freeze();
 496                 }
 497
 498                 if (!m) {
 499                         if (iov_iter_zero(tsz, iter) != tsz) {
 500                                 ret = -EFAULT;
 501                                 goto out;
 502                         }
 503                         goto skip;
 504                 }
 505
 506                 switch (m->type) {
 507                 case KCORE_VMALLOC:
 508                 {
 509                         const char *src = (char *)start;
 510                         size_t read = 0, left = tsz;
 511
 512                         /*
 513                          * vmalloc uses spinlocks, so we optimistically try to
 514                          * read memory. If this fails, fault pages in and try
 515                          * again until we are done.
 516                          */
 517                         while (true) {
 518                                 read += vread_iter(iter, src, left);
 519                                 if (read == tsz)
 520                                         break;
 521
 522                                 src += read;
 523                                 left -= read;
 524
 525                                 if (fault_in_iov_iter_writeable(iter, left)) {
 526                                         ret = -EFAULT;
 527                                         goto out;
 528                                 }
 529                         }
 530                         break;
 531                 }
 532                 case KCORE_USER:
 533                         /* User page is handled prior to normal kernel page: */
 534                         if (copy_to_iter((char *)start, tsz, iter) != tsz) {
 535                                 ret = -EFAULT;
 536                                 goto out;
 537                         }
 538                         break;
 539                 case KCORE_RAM:
 540                         pfn = __pa(start) >> PAGE_SHIFT;
 541                         page = pfn_to_online_page(pfn);
 542
 543                         /*
 544                          * Don't read offline sections, logically offline pages
 545                          * (e.g., inflated in a balloon), hwpoisoned pages,
 546                          * and explicitly excluded physical ranges.
 547                          */
 548                         if (!page || PageOffline(page) ||
 549                             is_page_hwpoison(page) || !pfn_is_ram(pfn) ||
 550                             pfn_is_unaccepted_memory(pfn)) {
 551                                 if (iov_iter_zero(tsz, iter) != tsz) {
 552                                         ret = -EFAULT;
 553                                         goto out;
 554                                 }
 555                                 break;
 556                         }
 557                         fallthrough;
 558                 case KCORE_VMEMMAP:
 559                 case KCORE_TEXT:
 560                         /*
 561                          * Sadly we must use a bounce buffer here to be able to
 562                          * make use of copy_from_kernel_nofault(), as these
 563                          * memory regions might not always be mapped on all
 564                          * architectures.
 565                          */
 566                         if (copy_from_kernel_nofault(buf, (void *)start, tsz)) {
 567                                 if (iov_iter_zero(tsz, iter) != tsz) {
 568                                         ret = -EFAULT;
 569                                         goto out;
 570                                 }
 571                         /*
 572                          * We know the bounce buffer is safe to copy from, so
 573                          * use _copy_to_iter() directly.
 574                          */
 575                         } else if (_copy_to_iter(buf, tsz, iter) != tsz) {
 576                                 ret = -EFAULT;
 577                                 goto out;
 578                         }
 579                         break;
 580                 default:
 581                         pr_warn_once("Unhandled KCORE type: %d\n", m->type);
 582                         if (iov_iter_zero(tsz, iter) != tsz) {
 583                                 ret = -EFAULT;
 584                                 goto out;
 585                         }
 586                 }
 587 skip:
 588                 buflen -= tsz;
 589                 *fpos += tsz;
 590                 start += tsz;
 591                 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
 592         }
 593
 594 out:
 595         page_offline_thaw();
 596         up_read(&kclist_lock);
 597         if (ret)
 598                 return ret;
 599         return orig_buflen - buflen;
 600 }
 601
 602 static int open_kcore(struct inode *inode, struct file *filp)
 603 {
 604         int ret = security_locked_down(LOCKDOWN_KCORE);
 605
 606         if (!capable(CAP_SYS_RAWIO))
 607                 return -EPERM;
 608
 609         if (ret)
 610                 return ret;
 611
 612         filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
 613         if (!filp->private_data)
 614                 return -ENOMEM;
 615
 616         if (kcore_need_update)
 617                 kcore_update_ram();
 618         if (i_size_read(inode) != proc_root_kcore->size) {
 619                 inode_lock(inode);
 620                 i_size_write(inode, proc_root_kcore->size);
 621                 inode_unlock(inode);
 622         }
 623         return 0;
 624 }
 625
 626 static int release_kcore(struct inode *inode, struct file *file)
 627 {
 628         kfree(file->private_data);
 629         return 0;
 630 }
 631
 632 static const struct proc_ops kcore_proc_ops = {
 633         .proc_read_iter = read_kcore_iter,
 634         .proc_open      = open_kcore,
 635         .proc_release   = release_kcore,
 636         .proc_lseek     = default_llseek,
 637 };
 638
 639 /* just remember that we have to update kcore */
 640 static int __meminit kcore_callback(struct notifier_block *self,
 641                                     unsigned long action, void *arg)
 642 {
 643         switch (action) {
 644         case MEM_ONLINE:
 645         case MEM_OFFLINE:
 646                 kcore_need_update = 1;
 647                 break;
 648         }
 649         return NOTIFY_OK;
 650 }
 651
 652
 653 static struct kcore_list kcore_vmalloc;
 654
 655 #ifdef CONFIG_ARCH_PROC_KCORE_TEXT
 656 static struct kcore_list kcore_text;
 657 /*
 658  * If defined, special segment is used for mapping kernel text instead of
 659  * direct-map area. We need to create special TEXT section.
 660  */
 661 static void __init proc_kcore_text_init(void)
 662 {
 663         kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
 664 }
 665 #else
 666 static void __init proc_kcore_text_init(void)
 667 {
 668 }
 669 #endif
 670
 671 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
 672 /*
 673  * MODULES_VADDR has no intersection with VMALLOC_ADDR.
 674  */
 675 static struct kcore_list kcore_modules;
 676 static void __init add_modules_range(void)
 677 {
 678         if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
 679                 kclist_add(&kcore_modules, (void *)MODULES_VADDR,
 680                         MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
 681         }
 682 }
 683 #else
 684 static void __init add_modules_range(void)
 685 {
 686 }
 687 #endif
 688
 689 static int __init proc_kcore_init(void)
 690 {
 691         proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &kcore_proc_ops);
 692         if (!proc_root_kcore) {
 693                 pr_err("couldn't create /proc/kcore\n");
 694                 return 0; /* Always returns 0. */
 695         }
 696         /* Store text area if it's special */
 697         proc_kcore_text_init();
 698         /* Store vmalloc area */
 699         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 700                 VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
 701         add_modules_range();
 702         /* Store direct-map area from physical memory map */
 703         kcore_update_ram();
 704         hotplug_memory_notifier(kcore_callback, DEFAULT_CALLBACK_PRI);
 705
 706         return 0;
 707 }
 708 fs_initcall(proc_kcore_init);