linux/fs/proc/vmcore.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *      fs/proc/vmcore.c Interface for accessing the crash
   4 *                               dump from the system's previous life.
   5 *      Heavily borrowed from fs/proc/kcore.c
   6 *      Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
   7 *      Copyright (C) IBM Corporation, 2004. All rights reserved
   8 *
   9 */
  10
  11#include <linux/mm.h>
  12#include <linux/kcore.h>
  13#include <linux/user.h>
  14#include <linux/elf.h>
  15#include <linux/elfcore.h>
  16#include <linux/export.h>
  17#include <linux/slab.h>
  18#include <linux/highmem.h>
  19#include <linux/printk.h>
  20#include <linux/memblock.h>
  21#include <linux/init.h>
  22#include <linux/crash_dump.h>
  23#include <linux/list.h>
  24#include <linux/moduleparam.h>
  25#include <linux/mutex.h>
  26#include <linux/vmalloc.h>
  27#include <linux/pagemap.h>
  28#include <linux/uaccess.h>
  29#include <linux/mem_encrypt.h>
  30#include <asm/pgtable.h>
  31#include <asm/io.h>
  32#include "internal.h"
  33
  34/* List representing chunks of contiguous memory areas and their offsets in
  35 * vmcore file.
  36 */
  37static LIST_HEAD(vmcore_list);
  38
  39/* Stores the pointer to the buffer containing kernel elf core headers. */
  40static char *elfcorebuf;
  41static size_t elfcorebuf_sz;
  42static size_t elfcorebuf_sz_orig;
  43
  44static char *elfnotes_buf;
  45static size_t elfnotes_sz;
  46/* Size of all notes minus the device dump notes */
  47static size_t elfnotes_orig_sz;
  48
  49/* Total size of vmcore file. */
  50static u64 vmcore_size;
  51
  52static struct proc_dir_entry *proc_vmcore;
  53
  54#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
  55/* Device Dump list and mutex to synchronize access to list */
  56static LIST_HEAD(vmcoredd_list);
  57static DEFINE_MUTEX(vmcoredd_mutex);
  58
  59static bool vmcoredd_disabled;
  60core_param(novmcoredd, vmcoredd_disabled, bool, 0);
  61#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
  62
  63/* Device Dump Size */
  64static size_t vmcoredd_orig_sz;
  65
  66/*
  67 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
  68 * The called function has to take care of module refcounting.
  69 */
  70static int (*oldmem_pfn_is_ram)(unsigned long pfn);
  71
  72int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
  73{
  74        if (oldmem_pfn_is_ram)
  75                return -EBUSY;
  76        oldmem_pfn_is_ram = fn;
  77        return 0;
  78}
  79EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
  80
  81void unregister_oldmem_pfn_is_ram(void)
  82{
  83        oldmem_pfn_is_ram = NULL;
  84        wmb();
  85}
  86EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
  87
  88static int pfn_is_ram(unsigned long pfn)
  89{
  90        int (*fn)(unsigned long pfn);
  91        /* pfn is ram unless fn() checks pagetype */
  92        int ret = 1;
  93
  94        /*
  95         * Ask hypervisor if the pfn is really ram.
  96         * A ballooned page contains no data and reading from such a page
  97         * will cause high load in the hypervisor.
  98         */
  99        fn = oldmem_pfn_is_ram;
 100        if (fn)
 101                ret = fn(pfn);
 102
 103        return ret;
 104}
 105
 106/* Reads a page from the oldmem device from given offset. */
 107static ssize_t read_from_oldmem(char *buf, size_t count,
 108                                u64 *ppos, int userbuf,
 109                                bool encrypted)
 110{
 111        unsigned long pfn, offset;
 112        size_t nr_bytes;
 113        ssize_t read = 0, tmp;
 114
 115        if (!count)
 116                return 0;
 117
 118        offset = (unsigned long)(*ppos % PAGE_SIZE);
 119        pfn = (unsigned long)(*ppos / PAGE_SIZE);
 120
 121        do {
 122                if (count > (PAGE_SIZE - offset))
 123                        nr_bytes = PAGE_SIZE - offset;
 124                else
 125                        nr_bytes = count;
 126
 127                /* If pfn is not ram, return zeros for sparse dump files */
 128                if (pfn_is_ram(pfn) == 0)
 129                        memset(buf, 0, nr_bytes);
 130                else {
 131                        if (encrypted)
 132                                tmp = copy_oldmem_page_encrypted(pfn, buf,
 133                                                                 nr_bytes,
 134                                                                 offset,
 135                                                                 userbuf);
 136                        else
 137                                tmp = copy_oldmem_page(pfn, buf, nr_bytes,
 138                                                       offset, userbuf);
 139
 140                        if (tmp < 0)
 141                                return tmp;
 142                }
 143                *ppos += nr_bytes;
 144                count -= nr_bytes;
 145                buf += nr_bytes;
 146                read += nr_bytes;
 147                ++pfn;
 148                offset = 0;
 149        } while (count);
 150
 151        return read;
 152}
 153
 154/*
 155 * Architectures may override this function to allocate ELF header in 2nd kernel
 156 */
 157int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
 158{
 159        return 0;
 160}
 161
 162/*
 163 * Architectures may override this function to free header
 164 */
 165void __weak elfcorehdr_free(unsigned long long addr)
 166{}
 167
 168/*
 169 * Architectures may override this function to read from ELF header
 170 */
 171ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 172{
 173        return read_from_oldmem(buf, count, ppos, 0, sev_active());
 174}
 175
 176/*
 177 * Architectures may override this function to read from notes sections
 178 */
 179ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
 180{
 181        return read_from_oldmem(buf, count, ppos, 0, mem_encrypt_active());
 182}
 183
 184/*
 185 * Architectures may override this function to map oldmem
 186 */
 187int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
 188                                  unsigned long from, unsigned long pfn,
 189                                  unsigned long size, pgprot_t prot)
 190{
 191        prot = pgprot_encrypted(prot);
 192        return remap_pfn_range(vma, from, pfn, size, prot);
 193}
 194
 195/*
 196 * Architectures which support memory encryption override this.
 197 */
 198ssize_t __weak
 199copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
 200                           unsigned long offset, int userbuf)
 201{
 202        return copy_oldmem_page(pfn, buf, csize, offset, userbuf);
 203}
 204
 205/*
 206 * Copy to either kernel or user space
 207 */
 208static int copy_to(void *target, void *src, size_t size, int userbuf)
 209{
 210        if (userbuf) {
 211                if (copy_to_user((char __user *) target, src, size))
 212                        return -EFAULT;
 213        } else {
 214                memcpy(target, src, size);
 215        }
 216        return 0;
 217}
 218
 219#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
 220static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
 221{
 222        struct vmcoredd_node *dump;
 223        u64 offset = 0;
 224        int ret = 0;
 225        size_t tsz;
 226        char *buf;
 227
 228        mutex_lock(&vmcoredd_mutex);
 229        list_for_each_entry(dump, &vmcoredd_list, list) {
 230                if (start < offset + dump->size) {
 231                        tsz = min(offset + (u64)dump->size - start, (u64)size);
 232                        buf = dump->buf + start - offset;
 233                        if (copy_to(dst, buf, tsz, userbuf)) {
 234                                ret = -EFAULT;
 235                                goto out_unlock;
 236                        }
 237
 238                        size -= tsz;
 239                        start += tsz;
 240                        dst += tsz;
 241
 242                        /* Leave now if buffer filled already */
 243                        if (!size)
 244                                goto out_unlock;
 245                }
 246                offset += dump->size;
 247        }
 248
 249out_unlock:
 250        mutex_unlock(&vmcoredd_mutex);
 251        return ret;
 252}
 253
 254#ifdef CONFIG_MMU
 255static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
 256                               u64 start, size_t size)
 257{
 258        struct vmcoredd_node *dump;
 259        u64 offset = 0;
 260        int ret = 0;
 261        size_t tsz;
 262        char *buf;
 263
 264        mutex_lock(&vmcoredd_mutex);
 265        list_for_each_entry(dump, &vmcoredd_list, list) {
 266                if (start < offset + dump->size) {
 267                        tsz = min(offset + (u64)dump->size - start, (u64)size);
 268                        buf = dump->buf + start - offset;
 269                        if (remap_vmalloc_range_partial(vma, dst, buf, tsz)) {
 270                                ret = -EFAULT;
 271                                goto out_unlock;
 272                        }
 273
 274                        size -= tsz;
 275                        start += tsz;
 276                        dst += tsz;
 277
 278                        /* Leave now if buffer filled already */
 279                        if (!size)
 280                                goto out_unlock;
 281                }
 282                offset += dump->size;
 283        }
 284
 285out_unlock:
 286        mutex_unlock(&vmcoredd_mutex);
 287        return ret;
 288}
 289#endif /* CONFIG_MMU */
 290#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
 291
 292/* Read from the ELF header and then the crash dump. On error, negative value is
 293 * returned otherwise number of bytes read are returned.
 294 */
 295static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
 296                             int userbuf)
 297{
 298        ssize_t acc = 0, tmp;
 299        size_t tsz;
 300        u64 start;
 301        struct vmcore *m = NULL;
 302
 303        if (buflen == 0 || *fpos >= vmcore_size)
 304                return 0;
 305
 306        /* trim buflen to not go beyond EOF */
 307        if (buflen > vmcore_size - *fpos)
 308                buflen = vmcore_size - *fpos;
 309
 310        /* Read ELF core header */
 311        if (*fpos < elfcorebuf_sz) {
 312                tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
 313                if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
 314                        return -EFAULT;
 315                buflen -= tsz;
 316                *fpos += tsz;
 317                buffer += tsz;
 318                acc += tsz;
 319
 320                /* leave now if filled buffer already */
 321                if (buflen == 0)
 322                        return acc;
 323        }
 324
 325        /* Read Elf note segment */
 326        if (*fpos < elfcorebuf_sz + elfnotes_sz) {
 327                void *kaddr;
 328
 329                /* We add device dumps before other elf notes because the
 330                 * other elf notes may not fill the elf notes buffer
 331                 * completely and we will end up with zero-filled data
 332                 * between the elf notes and the device dumps. Tools will
 333                 * then try to decode this zero-filled data as valid notes
 334                 * and we don't want that. Hence, adding device dumps before
 335                 * the other elf notes ensure that zero-filled data can be
 336                 * avoided.
 337                 */
 338#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
 339                /* Read device dumps */
 340                if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
 341                        tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
 342                                  (size_t)*fpos, buflen);
 343                        start = *fpos - elfcorebuf_sz;
 344                        if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf))
 345                                return -EFAULT;
 346
 347                        buflen -= tsz;
 348                        *fpos += tsz;
 349                        buffer += tsz;
 350                        acc += tsz;
 351
 352                        /* leave now if filled buffer already */
 353                        if (!buflen)
 354                                return acc;
 355                }
 356#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
 357
 358                /* Read remaining elf notes */
 359                tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
 360                kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
 361                if (copy_to(buffer, kaddr, tsz, userbuf))
 362                        return -EFAULT;
 363
 364                buflen -= tsz;
 365                *fpos += tsz;
 366                buffer += tsz;
 367                acc += tsz;
 368
 369                /* leave now if filled buffer already */
 370                if (buflen == 0)
 371                        return acc;
 372        }
 373
 374        list_for_each_entry(m, &vmcore_list, list) {
 375                if (*fpos < m->offset + m->size) {
 376                        tsz = (size_t)min_t(unsigned long long,
 377                                            m->offset + m->size - *fpos,
 378                                            buflen);
 379                        start = m->paddr + *fpos - m->offset;
 380                        tmp = read_from_oldmem(buffer, tsz, &start,
 381                                               userbuf, mem_encrypt_active());
 382                        if (tmp < 0)
 383                                return tmp;
 384                        buflen -= tsz;
 385                        *fpos += tsz;
 386                        buffer += tsz;
 387                        acc += tsz;
 388
 389                        /* leave now if filled buffer already */
 390                        if (buflen == 0)
 391                                return acc;
 392                }
 393        }
 394
 395        return acc;
 396}
 397
 398static ssize_t read_vmcore(struct file *file, char __user *buffer,
 399                           size_t buflen, loff_t *fpos)
 400{
 401        return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
 402}
 403
 404/*
 405 * The vmcore fault handler uses the page cache and fills data using the
 406 * standard __vmcore_read() function.
 407 *
 408 * On s390 the fault handler is used for memory regions that can't be mapped
 409 * directly with remap_pfn_range().
 410 */
 411static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
 412{
 413#ifdef CONFIG_S390
 414        struct address_space *mapping = vmf->vma->vm_file->f_mapping;
 415        pgoff_t index = vmf->pgoff;
 416        struct page *page;
 417        loff_t offset;
 418        char *buf;
 419        int rc;
 420
 421        page = find_or_create_page(mapping, index, GFP_KERNEL);
 422        if (!page)
 423                return VM_FAULT_OOM;
 424        if (!PageUptodate(page)) {
 425                offset = (loff_t) index << PAGE_SHIFT;
 426                buf = __va((page_to_pfn(page) << PAGE_SHIFT));
 427                rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
 428                if (rc < 0) {
 429                        unlock_page(page);
 430                        put_page(page);
 431                        return vmf_error(rc);
 432                }
 433                SetPageUptodate(page);
 434        }
 435        unlock_page(page);
 436        vmf->page = page;
 437        return 0;
 438#else
 439        return VM_FAULT_SIGBUS;
 440#endif
 441}
 442
 443static const struct vm_operations_struct vmcore_mmap_ops = {
 444        .fault = mmap_vmcore_fault,
 445};
 446
 447/**
 448 * vmcore_alloc_buf - allocate buffer in vmalloc memory
 449 * @sizez: size of buffer
 450 *
 451 * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
 452 * the buffer to user-space by means of remap_vmalloc_range().
 453 *
 454 * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
 455 * disabled and there's no need to allow users to mmap the buffer.
 456 */
 457static inline char *vmcore_alloc_buf(size_t size)
 458{
 459#ifdef CONFIG_MMU
 460        return vmalloc_user(size);
 461#else
 462        return vzalloc(size);
 463#endif
 464}
 465
 466/*
 467 * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
 468 * essential for mmap_vmcore() in order to map physically
 469 * non-contiguous objects (ELF header, ELF note segment and memory
 470 * regions in the 1st kernel pointed to by PT_LOAD entries) into
 471 * virtually contiguous user-space in ELF layout.
 472 */
 473#ifdef CONFIG_MMU
 474/*
 475 * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
 476 * reported as not being ram with the zero page.
 477 *
 478 * @vma: vm_area_struct describing requested mapping
 479 * @from: start remapping from
 480 * @pfn: page frame number to start remapping to
 481 * @size: remapping size
 482 * @prot: protection bits
 483 *
 484 * Returns zero on success, -EAGAIN on failure.
 485 */
 486static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
 487                                    unsigned long from, unsigned long pfn,
 488                                    unsigned long size, pgprot_t prot)
 489{
 490        unsigned long map_size;
 491        unsigned long pos_start, pos_end, pos;
 492        unsigned long zeropage_pfn = my_zero_pfn(0);
 493        size_t len = 0;
 494
 495        pos_start = pfn;
 496        pos_end = pfn + (size >> PAGE_SHIFT);
 497
 498        for (pos = pos_start; pos < pos_end; ++pos) {
 499                if (!pfn_is_ram(pos)) {
 500                        /*
 501                         * We hit a page which is not ram. Remap the continuous
 502                         * region between pos_start and pos-1 and replace
 503                         * the non-ram page at pos with the zero page.
 504                         */
 505                        if (pos > pos_start) {
 506                                /* Remap continuous region */
 507                                map_size = (pos - pos_start) << PAGE_SHIFT;
 508                                if (remap_oldmem_pfn_range(vma, from + len,
 509                                                           pos_start, map_size,
 510                                                           prot))
 511                                        goto fail;
 512                                len += map_size;
 513                        }
 514                        /* Remap the zero page */
 515                        if (remap_oldmem_pfn_range(vma, from + len,
 516                                                   zeropage_pfn,
 517                                                   PAGE_SIZE, prot))
 518                                goto fail;
 519                        len += PAGE_SIZE;
 520                        pos_start = pos + 1;
 521                }
 522        }
 523        if (pos > pos_start) {
 524                /* Remap the rest */
 525                map_size = (pos - pos_start) << PAGE_SHIFT;
 526                if (remap_oldmem_pfn_range(vma, from + len, pos_start,
 527                                           map_size, prot))
 528                        goto fail;
 529        }
 530        return 0;
 531fail:
 532        do_munmap(vma->vm_mm, from, len, NULL);
 533        return -EAGAIN;
 534}
 535
 536static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
 537                            unsigned long from, unsigned long pfn,
 538                            unsigned long size, pgprot_t prot)
 539{
 540        /*
 541         * Check if oldmem_pfn_is_ram was registered to avoid
 542         * looping over all pages without a reason.
 543         */
 544        if (oldmem_pfn_is_ram)
 545                return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
 546        else
 547                return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
 548}
 549
 550static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
 551{
 552        size_t size = vma->vm_end - vma->vm_start;
 553        u64 start, end, len, tsz;
 554        struct vmcore *m;
 555
 556        start = (u64)vma->vm_pgoff << PAGE_SHIFT;
 557        end = start + size;
 558
 559        if (size > vmcore_size || end > vmcore_size)
 560                return -EINVAL;
 561
 562        if (vma->vm_flags & (VM_WRITE | VM_EXEC))
 563                return -EPERM;
 564
 565        vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
 566        vma->vm_flags |= VM_MIXEDMAP;
 567        vma->vm_ops = &vmcore_mmap_ops;
 568
 569        len = 0;
 570
 571        if (start < elfcorebuf_sz) {
 572                u64 pfn;
 573
 574                tsz = min(elfcorebuf_sz - (size_t)start, size);
 575                pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
 576                if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
 577                                    vma->vm_page_prot))
 578                        return -EAGAIN;
 579                size -= tsz;
 580                start += tsz;
 581                len += tsz;
 582
 583                if (size == 0)
 584                        return 0;
 585        }
 586
 587        if (start < elfcorebuf_sz + elfnotes_sz) {
 588                void *kaddr;
 589
 590                /* We add device dumps before other elf notes because the
 591                 * other elf notes may not fill the elf notes buffer
 592                 * completely and we will end up with zero-filled data
 593                 * between the elf notes and the device dumps. Tools will
 594                 * then try to decode this zero-filled data as valid notes
 595                 * and we don't want that. Hence, adding device dumps before
 596                 * the other elf notes ensure that zero-filled data can be
 597                 * avoided. This also ensures that the device dumps and
 598                 * other elf notes can be properly mmaped at page aligned
 599                 * address.
 600                 */
 601#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
 602                /* Read device dumps */
 603                if (start < elfcorebuf_sz + vmcoredd_orig_sz) {
 604                        u64 start_off;
 605
 606                        tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
 607                                  (size_t)start, size);
 608                        start_off = start - elfcorebuf_sz;
 609                        if (vmcoredd_mmap_dumps(vma, vma->vm_start + len,
 610                                                start_off, tsz))
 611                                goto fail;
 612
 613                        size -= tsz;
 614                        start += tsz;
 615                        len += tsz;
 616
 617                        /* leave now if filled buffer already */
 618                        if (!size)
 619                                return 0;
 620                }
 621#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
 622
 623                /* Read remaining elf notes */
 624                tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
 625                kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_sz;
 626                if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
 627                                                kaddr, tsz))
 628                        goto fail;
 629
 630                size -= tsz;
 631                start += tsz;
 632                len += tsz;
 633
 634                if (size == 0)
 635                        return 0;
 636        }
 637
 638        list_for_each_entry(m, &vmcore_list, list) {
 639                if (start < m->offset + m->size) {
 640                        u64 paddr = 0;
 641
 642                        tsz = (size_t)min_t(unsigned long long,
 643                                            m->offset + m->size - start, size);
 644                        paddr = m->paddr + start - m->offset;
 645                        if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
 646                                                    paddr >> PAGE_SHIFT, tsz,
 647                                                    vma->vm_page_prot))
 648                                goto fail;
 649                        size -= tsz;
 650                        start += tsz;
 651                        len += tsz;
 652
 653                        if (size == 0)
 654                                return 0;
 655                }
 656        }
 657
 658        return 0;
 659fail:
 660        do_munmap(vma->vm_mm, vma->vm_start, len, NULL);
 661        return -EAGAIN;
 662}
 663#else
 664static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
 665{
 666        return -ENOSYS;
 667}
 668#endif
 669
 670static const struct file_operations proc_vmcore_operations = {
 671        .read           = read_vmcore,
 672        .llseek         = default_llseek,
 673        .mmap           = mmap_vmcore,
 674};
 675
 676static struct vmcore* __init get_new_element(void)
 677{
 678        return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
 679}
 680
 681static u64 get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
 682                           struct list_head *vc_list)
 683{
 684        u64 size;
 685        struct vmcore *m;
 686
 687        size = elfsz + elfnotesegsz;
 688        list_for_each_entry(m, vc_list, list) {
 689                size += m->size;
 690        }
 691        return size;
 692}
 693
 694/**
 695 * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
 696 *
 697 * @ehdr_ptr: ELF header
 698 *
 699 * This function updates p_memsz member of each PT_NOTE entry in the
 700 * program header table pointed to by @ehdr_ptr to real size of ELF
 701 * note segment.
 702 */
 703static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
 704{
 705        int i, rc=0;
 706        Elf64_Phdr *phdr_ptr;
 707        Elf64_Nhdr *nhdr_ptr;
 708
 709        phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
 710        for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 711                void *notes_section;
 712                u64 offset, max_sz, sz, real_sz = 0;
 713                if (phdr_ptr->p_type != PT_NOTE)
 714                        continue;
 715                max_sz = phdr_ptr->p_memsz;
 716                offset = phdr_ptr->p_offset;
 717                notes_section = kmalloc(max_sz, GFP_KERNEL);
 718                if (!notes_section)
 719                        return -ENOMEM;
 720                rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
 721                if (rc < 0) {
 722                        kfree(notes_section);
 723                        return rc;
 724                }
 725                nhdr_ptr = notes_section;
 726                while (nhdr_ptr->n_namesz != 0) {
 727                        sz = sizeof(Elf64_Nhdr) +
 728                                (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
 729                                (((u64)nhdr_ptr->n_descsz + 3) & ~3);
 730                        if ((real_sz + sz) > max_sz) {
 731                                pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
 732                                        nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
 733                                break;
 734                        }
 735                        real_sz += sz;
 736                        nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 737                }
 738                kfree(notes_section);
 739                phdr_ptr->p_memsz = real_sz;
 740                if (real_sz == 0) {
 741                        pr_warn("Warning: Zero PT_NOTE entries found\n");
 742                }
 743        }
 744
 745        return 0;
 746}
 747
 748/**
 749 * get_note_number_and_size_elf64 - get the number of PT_NOTE program
 750 * headers and sum of real size of their ELF note segment headers and
 751 * data.
 752 *
 753 * @ehdr_ptr: ELF header
 754 * @nr_ptnote: buffer for the number of PT_NOTE program headers
 755 * @sz_ptnote: buffer for size of unique PT_NOTE program header
 756 *
 757 * This function is used to merge multiple PT_NOTE program headers
 758 * into a unique single one. The resulting unique entry will have
 759 * @sz_ptnote in its phdr->p_mem.
 760 *
 761 * It is assumed that program headers with PT_NOTE type pointed to by
 762 * @ehdr_ptr has already been updated by update_note_header_size_elf64
 763 * and each of PT_NOTE program headers has actual ELF note segment
 764 * size in its p_memsz member.
 765 */
 766static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
 767                                                 int *nr_ptnote, u64 *sz_ptnote)
 768{
 769        int i;
 770        Elf64_Phdr *phdr_ptr;
 771
 772        *nr_ptnote = *sz_ptnote = 0;
 773
 774        phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
 775        for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 776                if (phdr_ptr->p_type != PT_NOTE)
 777                        continue;
 778                *nr_ptnote += 1;
 779                *sz_ptnote += phdr_ptr->p_memsz;
 780        }
 781
 782        return 0;
 783}
 784
 785/**
 786 * copy_notes_elf64 - copy ELF note segments in a given buffer
 787 *
 788 * @ehdr_ptr: ELF header
 789 * @notes_buf: buffer into which ELF note segments are copied
 790 *
 791 * This function is used to copy ELF note segment in the 1st kernel
 792 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
 793 * size of the buffer @notes_buf is equal to or larger than sum of the
 794 * real ELF note segment headers and data.
 795 *
 796 * It is assumed that program headers with PT_NOTE type pointed to by
 797 * @ehdr_ptr has already been updated by update_note_header_size_elf64
 798 * and each of PT_NOTE program headers has actual ELF note segment
 799 * size in its p_memsz member.
 800 */
 801static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
 802{
 803        int i, rc=0;
 804        Elf64_Phdr *phdr_ptr;
 805
 806        phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
 807
 808        for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 809                u64 offset;
 810                if (phdr_ptr->p_type != PT_NOTE)
 811                        continue;
 812                offset = phdr_ptr->p_offset;
 813                rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
 814                                           &offset);
 815                if (rc < 0)
 816                        return rc;
 817                notes_buf += phdr_ptr->p_memsz;
 818        }
 819
 820        return 0;
 821}
 822
 823/* Merges all the PT_NOTE headers into one. */
 824static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 825                                           char **notes_buf, size_t *notes_sz)
 826{
 827        int i, nr_ptnote=0, rc=0;
 828        char *tmp;
 829        Elf64_Ehdr *ehdr_ptr;
 830        Elf64_Phdr phdr;
 831        u64 phdr_sz = 0, note_off;
 832
 833        ehdr_ptr = (Elf64_Ehdr *)elfptr;
 834
 835        rc = update_note_header_size_elf64(ehdr_ptr);
 836        if (rc < 0)
 837                return rc;
 838
 839        rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
 840        if (rc < 0)
 841                return rc;
 842
 843        *notes_sz = roundup(phdr_sz, PAGE_SIZE);
 844        *notes_buf = vmcore_alloc_buf(*notes_sz);
 845        if (!*notes_buf)
 846                return -ENOMEM;
 847
 848        rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
 849        if (rc < 0)
 850                return rc;
 851
 852        /* Prepare merged PT_NOTE program header. */
 853        phdr.p_type    = PT_NOTE;
 854        phdr.p_flags   = 0;
 855        note_off = sizeof(Elf64_Ehdr) +
 856                        (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
 857        phdr.p_offset  = roundup(note_off, PAGE_SIZE);
 858        phdr.p_vaddr   = phdr.p_paddr = 0;
 859        phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 860        phdr.p_align   = 0;
 861
 862        /* Add merged PT_NOTE program header*/
 863        tmp = elfptr + sizeof(Elf64_Ehdr);
 864        memcpy(tmp, &phdr, sizeof(phdr));
 865        tmp += sizeof(phdr);
 866
 867        /* Remove unwanted PT_NOTE program headers. */
 868        i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
 869        *elfsz = *elfsz - i;
 870        memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
 871        memset(elfptr + *elfsz, 0, i);
 872        *elfsz = roundup(*elfsz, PAGE_SIZE);
 873
 874        /* Modify e_phnum to reflect merged headers. */
 875        ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 876
 877        /* Store the size of all notes.  We need this to update the note
 878         * header when the device dumps will be added.
 879         */
 880        elfnotes_orig_sz = phdr.p_memsz;
 881
 882        return 0;
 883}
 884
 885/**
 886 * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
 887 *
 888 * @ehdr_ptr: ELF header
 889 *
 890 * This function updates p_memsz member of each PT_NOTE entry in the
 891 * program header table pointed to by @ehdr_ptr to real size of ELF
 892 * note segment.
 893 */
 894static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
 895{
 896        int i, rc=0;
 897        Elf32_Phdr *phdr_ptr;
 898        Elf32_Nhdr *nhdr_ptr;
 899
 900        phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
 901        for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 902                void *notes_section;
 903                u64 offset, max_sz, sz, real_sz = 0;
 904                if (phdr_ptr->p_type != PT_NOTE)
 905                        continue;
 906                max_sz = phdr_ptr->p_memsz;
 907                offset = phdr_ptr->p_offset;
 908                notes_section = kmalloc(max_sz, GFP_KERNEL);
 909                if (!notes_section)
 910                        return -ENOMEM;
 911                rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
 912                if (rc < 0) {
 913                        kfree(notes_section);
 914                        return rc;
 915                }
 916                nhdr_ptr = notes_section;
 917                while (nhdr_ptr->n_namesz != 0) {
 918                        sz = sizeof(Elf32_Nhdr) +
 919                                (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
 920                                (((u64)nhdr_ptr->n_descsz + 3) & ~3);
 921                        if ((real_sz + sz) > max_sz) {
 922                                pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
 923                                        nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
 924                                break;
 925                        }
 926                        real_sz += sz;
 927                        nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 928                }
 929                kfree(notes_section);
 930                phdr_ptr->p_memsz = real_sz;
 931                if (real_sz == 0) {
 932                        pr_warn("Warning: Zero PT_NOTE entries found\n");
 933                }
 934        }
 935
 936        return 0;
 937}
 938
 939/**
 940 * get_note_number_and_size_elf32 - get the number of PT_NOTE program
 941 * headers and sum of real size of their ELF note segment headers and
 942 * data.
 943 *
 944 * @ehdr_ptr: ELF header
 945 * @nr_ptnote: buffer for the number of PT_NOTE program headers
 946 * @sz_ptnote: buffer for size of unique PT_NOTE program header
 947 *
 948 * This function is used to merge multiple PT_NOTE program headers
 949 * into a unique single one. The resulting unique entry will have
 950 * @sz_ptnote in its phdr->p_mem.
 951 *
 952 * It is assumed that program headers with PT_NOTE type pointed to by
 953 * @ehdr_ptr has already been updated by update_note_header_size_elf32
 954 * and each of PT_NOTE program headers has actual ELF note segment
 955 * size in its p_memsz member.
 956 */
 957static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
 958                                                 int *nr_ptnote, u64 *sz_ptnote)
 959{
 960        int i;
 961        Elf32_Phdr *phdr_ptr;
 962
 963        *nr_ptnote = *sz_ptnote = 0;
 964
 965        phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
 966        for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 967                if (phdr_ptr->p_type != PT_NOTE)
 968                        continue;
 969                *nr_ptnote += 1;
 970                *sz_ptnote += phdr_ptr->p_memsz;
 971        }
 972
 973        return 0;
 974}
 975
 976/**
 977 * copy_notes_elf32 - copy ELF note segments in a given buffer
 978 *
 979 * @ehdr_ptr: ELF header
 980 * @notes_buf: buffer into which ELF note segments are copied
 981 *
 982 * This function is used to copy ELF note segment in the 1st kernel
 983 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
 984 * size of the buffer @notes_buf is equal to or larger than sum of the
 985 * real ELF note segment headers and data.
 986 *
 987 * It is assumed that program headers with PT_NOTE type pointed to by
 988 * @ehdr_ptr has already been updated by update_note_header_size_elf32
 989 * and each of PT_NOTE program headers has actual ELF note segment
 990 * size in its p_memsz member.
 991 */
 992static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
 993{
 994        int i, rc=0;
 995        Elf32_Phdr *phdr_ptr;
 996
 997        phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
 998
 999        for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1000                u64 offset;
1001                if (phdr_ptr->p_type != PT_NOTE)
1002                        continue;
1003                offset = phdr_ptr->p_offset;
1004                rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
1005                                           &offset);
1006                if (rc < 0)
1007                        return rc;
1008                notes_buf += phdr_ptr->p_memsz;
1009        }
1010
1011        return 0;
1012}
1013
1014/* Merges all the PT_NOTE headers into one. */
1015static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
1016                                           char **notes_buf, size_t *notes_sz)
1017{
1018        int i, nr_ptnote=0, rc=0;
1019        char *tmp;
1020        Elf32_Ehdr *ehdr_ptr;
1021        Elf32_Phdr phdr;
1022        u64 phdr_sz = 0, note_off;
1023
1024        ehdr_ptr = (Elf32_Ehdr *)elfptr;
1025
1026        rc = update_note_header_size_elf32(ehdr_ptr);
1027        if (rc < 0)
1028                return rc;
1029
1030        rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
1031        if (rc < 0)
1032                return rc;
1033
1034        *notes_sz = roundup(phdr_sz, PAGE_SIZE);
1035        *notes_buf = vmcore_alloc_buf(*notes_sz);
1036        if (!*notes_buf)
1037                return -ENOMEM;
1038
1039        rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
1040        if (rc < 0)
1041                return rc;
1042
1043        /* Prepare merged PT_NOTE program header. */
1044        phdr.p_type    = PT_NOTE;
1045        phdr.p_flags   = 0;
1046        note_off = sizeof(Elf32_Ehdr) +
1047                        (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
1048        phdr.p_offset  = roundup(note_off, PAGE_SIZE);
1049        phdr.p_vaddr   = phdr.p_paddr = 0;
1050        phdr.p_filesz  = phdr.p_memsz = phdr_sz;
1051        phdr.p_align   = 0;
1052
1053        /* Add merged PT_NOTE program header*/
1054        tmp = elfptr + sizeof(Elf32_Ehdr);
1055        memcpy(tmp, &phdr, sizeof(phdr));
1056        tmp += sizeof(phdr);
1057
1058        /* Remove unwanted PT_NOTE program headers. */
1059        i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
1060        *elfsz = *elfsz - i;
1061        memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
1062        memset(elfptr + *elfsz, 0, i);
1063        *elfsz = roundup(*elfsz, PAGE_SIZE);
1064
1065        /* Modify e_phnum to reflect merged headers. */
1066        ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
1067
1068        /* Store the size of all notes.  We need this to update the note
1069         * header when the device dumps will be added.
1070         */
1071        elfnotes_orig_sz = phdr.p_memsz;
1072
1073        return 0;
1074}
1075
1076/* Add memory chunks represented by program headers to vmcore list. Also update
1077 * the new offset fields of exported program headers. */
1078static int __init process_ptload_program_headers_elf64(char *elfptr,
1079                                                size_t elfsz,
1080                                                size_t elfnotes_sz,
1081                                                struct list_head *vc_list)
1082{
1083        int i;
1084        Elf64_Ehdr *ehdr_ptr;
1085        Elf64_Phdr *phdr_ptr;
1086        loff_t vmcore_off;
1087        struct vmcore *new;
1088
1089        ehdr_ptr = (Elf64_Ehdr *)elfptr;
1090        phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
1091
1092        /* Skip Elf header, program headers and Elf note segment. */
1093        vmcore_off = elfsz + elfnotes_sz;
1094
1095        for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1096                u64 paddr, start, end, size;
1097
1098                if (phdr_ptr->p_type != PT_LOAD)
1099                        continue;
1100
1101                paddr = phdr_ptr->p_offset;
1102                start = rounddown(paddr, PAGE_SIZE);
1103                end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1104                size = end - start;
1105
1106                /* Add this contiguous chunk of memory to vmcore list.*/
1107                new = get_new_element();
1108                if (!new)
1109                        return -ENOMEM;
1110                new->paddr = start;
1111                new->size = size;
1112                list_add_tail(&new->list, vc_list);
1113
1114                /* Update the program header offset. */
1115                phdr_ptr->p_offset = vmcore_off + (paddr - start);
1116                vmcore_off = vmcore_off + size;
1117        }
1118        return 0;
1119}
1120
1121static int __init process_ptload_program_headers_elf32(char *elfptr,
1122                                                size_t elfsz,
1123                                                size_t elfnotes_sz,
1124                                                struct list_head *vc_list)
1125{
1126        int i;
1127        Elf32_Ehdr *ehdr_ptr;
1128        Elf32_Phdr *phdr_ptr;
1129        loff_t vmcore_off;
1130        struct vmcore *new;
1131
1132        ehdr_ptr = (Elf32_Ehdr *)elfptr;
1133        phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
1134
1135        /* Skip Elf header, program headers and Elf note segment. */
1136        vmcore_off = elfsz + elfnotes_sz;
1137
1138        for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1139                u64 paddr, start, end, size;
1140
1141                if (phdr_ptr->p_type != PT_LOAD)
1142                        continue;
1143
1144                paddr = phdr_ptr->p_offset;
1145                start = rounddown(paddr, PAGE_SIZE);
1146                end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1147                size = end - start;
1148
1149                /* Add this contiguous chunk of memory to vmcore list.*/
1150                new = get_new_element();
1151                if (!new)
1152                        return -ENOMEM;
1153                new->paddr = start;
1154                new->size = size;
1155                list_add_tail(&new->list, vc_list);
1156
1157                /* Update the program header offset */
1158                phdr_ptr->p_offset = vmcore_off + (paddr - start);
1159                vmcore_off = vmcore_off + size;
1160        }
1161        return 0;
1162}
1163
1164/* Sets offset fields of vmcore elements. */
1165static void set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
1166                                    struct list_head *vc_list)
1167{
1168        loff_t vmcore_off;
1169        struct vmcore *m;
1170
1171        /* Skip Elf header, program headers and Elf note segment. */
1172        vmcore_off = elfsz + elfnotes_sz;
1173
1174        list_for_each_entry(m, vc_list, list) {
1175                m->offset = vmcore_off;
1176                vmcore_off += m->size;
1177        }
1178}
1179
1180static void free_elfcorebuf(void)
1181{
1182        free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
1183        elfcorebuf = NULL;
1184        vfree(elfnotes_buf);
1185        elfnotes_buf = NULL;
1186}
1187
1188static int __init parse_crash_elf64_headers(void)
1189{
1190        int rc=0;
1191        Elf64_Ehdr ehdr;
1192        u64 addr;
1193
1194        addr = elfcorehdr_addr;
1195
1196        /* Read Elf header */
1197        rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
1198        if (rc < 0)
1199                return rc;
1200
1201        /* Do some basic Verification. */
1202        if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1203                (ehdr.e_type != ET_CORE) ||
1204                !vmcore_elf64_check_arch(&ehdr) ||
1205                ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
1206                ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1207                ehdr.e_version != EV_CURRENT ||
1208                ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
1209                ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
1210                ehdr.e_phnum == 0) {
1211                pr_warn("Warning: Core image elf header is not sane\n");
1212                return -EINVAL;
1213        }
1214
1215        /* Read in all elf headers. */
1216        elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
1217                                ehdr.e_phnum * sizeof(Elf64_Phdr);
1218        elfcorebuf_sz = elfcorebuf_sz_orig;
1219        elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1220                                              get_order(elfcorebuf_sz_orig));
1221        if (!elfcorebuf)
1222                return -ENOMEM;
1223        addr = elfcorehdr_addr;
1224        rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1225        if (rc < 0)
1226                goto fail;
1227
1228        /* Merge all PT_NOTE headers into one. */
1229        rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
1230                                      &elfnotes_buf, &elfnotes_sz);
1231        if (rc)
1232                goto fail;
1233        rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
1234                                                  elfnotes_sz, &vmcore_list);
1235        if (rc)
1236                goto fail;
1237        set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1238        return 0;
1239fail:
1240        free_elfcorebuf();
1241        return rc;
1242}
1243
1244static int __init parse_crash_elf32_headers(void)
1245{
1246        int rc=0;
1247        Elf32_Ehdr ehdr;
1248        u64 addr;
1249
1250        addr = elfcorehdr_addr;
1251
1252        /* Read Elf header */
1253        rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
1254        if (rc < 0)
1255                return rc;
1256
1257        /* Do some basic Verification. */
1258        if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1259                (ehdr.e_type != ET_CORE) ||
1260                !vmcore_elf32_check_arch(&ehdr) ||
1261                ehdr.e_ident[EI_CLASS] != ELFCLASS32||
1262                ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1263                ehdr.e_version != EV_CURRENT ||
1264                ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1265                ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1266                ehdr.e_phnum == 0) {
1267                pr_warn("Warning: Core image elf header is not sane\n");
1268                return -EINVAL;
1269        }
1270
1271        /* Read in all elf headers. */
1272        elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1273        elfcorebuf_sz = elfcorebuf_sz_orig;
1274        elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1275                                              get_order(elfcorebuf_sz_orig));
1276        if (!elfcorebuf)
1277                return -ENOMEM;
1278        addr = elfcorehdr_addr;
1279        rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1280        if (rc < 0)
1281                goto fail;
1282
1283        /* Merge all PT_NOTE headers into one. */
1284        rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1285                                      &elfnotes_buf, &elfnotes_sz);
1286        if (rc)
1287                goto fail;
1288        rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1289                                                  elfnotes_sz, &vmcore_list);
1290        if (rc)
1291                goto fail;
1292        set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1293        return 0;
1294fail:
1295        free_elfcorebuf();
1296        return rc;
1297}
1298
1299static int __init parse_crash_elf_headers(void)
1300{
1301        unsigned char e_ident[EI_NIDENT];
1302        u64 addr;
1303        int rc=0;
1304
1305        addr = elfcorehdr_addr;
1306        rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1307        if (rc < 0)
1308                return rc;
1309        if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1310                pr_warn("Warning: Core image elf header not found\n");
1311                return -EINVAL;
1312        }
1313
1314        if (e_ident[EI_CLASS] == ELFCLASS64) {
1315                rc = parse_crash_elf64_headers();
1316                if (rc)
1317                        return rc;
1318        } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1319                rc = parse_crash_elf32_headers();
1320                if (rc)
1321                        return rc;
1322        } else {
1323                pr_warn("Warning: Core image elf header is not sane\n");
1324                return -EINVAL;
1325        }
1326
1327        /* Determine vmcore size. */
1328        vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1329                                      &vmcore_list);
1330
1331        return 0;
1332}
1333
1334#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1335/**
1336 * vmcoredd_write_header - Write vmcore device dump header at the
1337 * beginning of the dump's buffer.
1338 * @buf: Output buffer where the note is written
1339 * @data: Dump info
1340 * @size: Size of the dump
1341 *
1342 * Fills beginning of the dump's buffer with vmcore device dump header.
1343 */
1344static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data,
1345                                  u32 size)
1346{
1347        struct vmcoredd_header *vdd_hdr = (struct vmcoredd_header *)buf;
1348
1349        vdd_hdr->n_namesz = sizeof(vdd_hdr->name);
1350        vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name);
1351        vdd_hdr->n_type = NT_VMCOREDD;
1352
1353        strncpy((char *)vdd_hdr->name, VMCOREDD_NOTE_NAME,
1354                sizeof(vdd_hdr->name));
1355        memcpy(vdd_hdr->dump_name, data->dump_name, sizeof(vdd_hdr->dump_name));
1356}
1357
1358/**
1359 * vmcoredd_update_program_headers - Update all Elf program headers
1360 * @elfptr: Pointer to elf header
1361 * @elfnotesz: Size of elf notes aligned to page size
1362 * @vmcoreddsz: Size of device dumps to be added to elf note header
1363 *
1364 * Determine type of Elf header (Elf64 or Elf32) and update the elf note size.
1365 * Also update the offsets of all the program headers after the elf note header.
1366 */
1367static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz,
1368                                            size_t vmcoreddsz)
1369{
1370        unsigned char *e_ident = (unsigned char *)elfptr;
1371        u64 start, end, size;
1372        loff_t vmcore_off;
1373        u32 i;
1374
1375        vmcore_off = elfcorebuf_sz + elfnotesz;
1376
1377        if (e_ident[EI_CLASS] == ELFCLASS64) {
1378                Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr;
1379                Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr));
1380
1381                /* Update all program headers */
1382                for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1383                        if (phdr->p_type == PT_NOTE) {
1384                                /* Update note size */
1385                                phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1386                                phdr->p_filesz = phdr->p_memsz;
1387                                continue;
1388                        }
1389
1390                        start = rounddown(phdr->p_offset, PAGE_SIZE);
1391                        end = roundup(phdr->p_offset + phdr->p_memsz,
1392                                      PAGE_SIZE);
1393                        size = end - start;
1394                        phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1395                        vmcore_off += size;
1396                }
1397        } else {
1398                Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr;
1399                Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr));
1400
1401                /* Update all program headers */
1402                for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1403                        if (phdr->p_type == PT_NOTE) {
1404                                /* Update note size */
1405                                phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1406                                phdr->p_filesz = phdr->p_memsz;
1407                                continue;
1408                        }
1409
1410                        start = rounddown(phdr->p_offset, PAGE_SIZE);
1411                        end = roundup(phdr->p_offset + phdr->p_memsz,
1412                                      PAGE_SIZE);
1413                        size = end - start;
1414                        phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1415                        vmcore_off += size;
1416                }
1417        }
1418}
1419
1420/**
1421 * vmcoredd_update_size - Update the total size of the device dumps and update
1422 * Elf header
1423 * @dump_size: Size of the current device dump to be added to total size
1424 *
1425 * Update the total size of all the device dumps and update the Elf program
1426 * headers. Calculate the new offsets for the vmcore list and update the
1427 * total vmcore size.
1428 */
1429static void vmcoredd_update_size(size_t dump_size)
1430{
1431        vmcoredd_orig_sz += dump_size;
1432        elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz;
1433        vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz,
1434                                        vmcoredd_orig_sz);
1435
1436        /* Update vmcore list offsets */
1437        set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1438
1439        vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1440                                      &vmcore_list);
1441        proc_vmcore->size = vmcore_size;
1442}
1443
1444/**
1445 * vmcore_add_device_dump - Add a buffer containing device dump to vmcore
1446 * @data: dump info.
1447 *
1448 * Allocate a buffer and invoke the calling driver's dump collect routine.
1449 * Write Elf note at the beginning of the buffer to indicate vmcore device
1450 * dump and add the dump to global list.
1451 */
1452int vmcore_add_device_dump(struct vmcoredd_data *data)
1453{
1454        struct vmcoredd_node *dump;
1455        void *buf = NULL;
1456        size_t data_size;
1457        int ret;
1458
1459        if (vmcoredd_disabled) {
1460                pr_err_once("Device dump is disabled\n");
1461                return -EINVAL;
1462        }
1463
1464        if (!data || !strlen(data->dump_name) ||
1465            !data->vmcoredd_callback || !data->size)
1466                return -EINVAL;
1467
1468        dump = vzalloc(sizeof(*dump));
1469        if (!dump) {
1470                ret = -ENOMEM;
1471                goto out_err;
1472        }
1473
1474        /* Keep size of the buffer page aligned so that it can be mmaped */
1475        data_size = roundup(sizeof(struct vmcoredd_header) + data->size,
1476                            PAGE_SIZE);
1477
1478        /* Allocate buffer for driver's to write their dumps */
1479        buf = vmcore_alloc_buf(data_size);
1480        if (!buf) {
1481                ret = -ENOMEM;
1482                goto out_err;
1483        }
1484
1485        vmcoredd_write_header(buf, data, data_size -
1486                              sizeof(struct vmcoredd_header));
1487
1488        /* Invoke the driver's dump collection routing */
1489        ret = data->vmcoredd_callback(data, buf +
1490                                      sizeof(struct vmcoredd_header));
1491        if (ret)
1492                goto out_err;
1493
1494        dump->buf = buf;
1495        dump->size = data_size;
1496
1497        /* Add the dump to driver sysfs list */
1498        mutex_lock(&vmcoredd_mutex);
1499        list_add_tail(&dump->list, &vmcoredd_list);
1500        mutex_unlock(&vmcoredd_mutex);
1501
1502        vmcoredd_update_size(data_size);
1503        return 0;
1504
1505out_err:
1506        if (buf)
1507                vfree(buf);
1508
1509        if (dump)
1510                vfree(dump);
1511
1512        return ret;
1513}
1514EXPORT_SYMBOL(vmcore_add_device_dump);
1515#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1516
1517/* Free all dumps in vmcore device dump list */
1518static void vmcore_free_device_dumps(void)
1519{
1520#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1521        mutex_lock(&vmcoredd_mutex);
1522        while (!list_empty(&vmcoredd_list)) {
1523                struct vmcoredd_node *dump;
1524
1525                dump = list_first_entry(&vmcoredd_list, struct vmcoredd_node,
1526                                        list);
1527                list_del(&dump->list);
1528                vfree(dump->buf);
1529                vfree(dump);
1530        }
1531        mutex_unlock(&vmcoredd_mutex);
1532#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1533}
1534
1535/* Init function for vmcore module. */
1536static int __init vmcore_init(void)
1537{
1538        int rc = 0;
1539
1540        /* Allow architectures to allocate ELF header in 2nd kernel */
1541        rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1542        if (rc)
1543                return rc;
1544        /*
1545         * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1546         * then capture the dump.
1547         */
1548        if (!(is_vmcore_usable()))
1549                return rc;
1550        rc = parse_crash_elf_headers();
1551        if (rc) {
1552                pr_warn("Kdump: vmcore not initialized\n");
1553                return rc;
1554        }
1555        elfcorehdr_free(elfcorehdr_addr);
1556        elfcorehdr_addr = ELFCORE_ADDR_ERR;
1557
1558        proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
1559        if (proc_vmcore)
1560                proc_vmcore->size = vmcore_size;
1561        return 0;
1562}
1563fs_initcall(vmcore_init);
1564
1565/* Cleanup function for vmcore module. */
1566void vmcore_cleanup(void)
1567{
1568        if (proc_vmcore) {
1569                proc_remove(proc_vmcore);
1570                proc_vmcore = NULL;
1571        }
1572
1573        /* clear the vmcore list. */
1574        while (!list_empty(&vmcore_list)) {
1575                struct vmcore *m;
1576
1577                m = list_first_entry(&vmcore_list, struct vmcore, list);
1578                list_del(&m->list);
1579                kfree(m);
1580        }
1581        free_elfcorebuf();
1582
1583        /* clear vmcore device dump list */
1584        vmcore_free_device_dumps();
1585}
1586