arch/x86/kernel/crash.c

   1 /*
   2  * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
   3  *
   4  * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
   5  *
   6  * Copyright (C) IBM Corporation, 2004. All rights reserved.
   7  * Copyright (C) Red Hat Inc., 2014. All rights reserved.
   8  * Authors:
   9  *      Vivek Goyal <vgoyal@redhat.com>
  10  *
  11  */
  12
  13 #define pr_fmt(fmt)     "kexec: " fmt
  14
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/smp.h>
  18 #include <linux/reboot.h>
  19 #include <linux/kexec.h>
  20 #include <linux/delay.h>
  21 #include <linux/elf.h>
  22 #include <linux/elfcore.h>
  23 #include <linux/export.h>
  24 #include <linux/slab.h>
  25 #include <linux/vmalloc.h>
  26
  27 #include <asm/processor.h>
  28 #include <asm/hardirq.h>
  29 #include <asm/nmi.h>
  30 #include <asm/hw_irq.h>
  31 #include <asm/apic.h>
  32 #include <asm/e820/types.h>
  33 #include <asm/io_apic.h>
  34 #include <asm/hpet.h>
  35 #include <linux/kdebug.h>
  36 #include <asm/cpu.h>
  37 #include <asm/reboot.h>
  38 #include <asm/virtext.h>
  39 #include <asm/intel_pt.h>
  40
  41 /* Alignment required for elf header segment */
  42 #define ELF_CORE_HEADER_ALIGN   4096
  43
  44 /* This primarily represents number of split ranges due to exclusion */
  45 #define CRASH_MAX_RANGES        16
  46
  47 struct crash_mem_range {
  48         u64 start, end;
  49 };
  50
  51 struct crash_mem {
  52         unsigned int nr_ranges;
  53         struct crash_mem_range ranges[CRASH_MAX_RANGES];
  54 };
  55
  56 /* Misc data about ram ranges needed to prepare elf headers */
  57 struct crash_elf_data {
  58         struct kimage *image;
  59         /*
  60          * Total number of ram ranges we have after various adjustments for
  61          * crash reserved region, etc.
  62          */
  63         unsigned int max_nr_ranges;
  64
  65         /* Pointer to elf header */
  66         void *ehdr;
  67         /* Pointer to next phdr */
  68         void *bufp;
  69         struct crash_mem mem;
  70 };
  71
  72 /* Used while preparing memory map entries for second kernel */
  73 struct crash_memmap_data {
  74         struct boot_params *params;
  75         /* Type of memory */
  76         unsigned int type;
  77 };
  78
  79 /*
  80  * This is used to VMCLEAR all VMCSs loaded on the
  81  * processor. And when loading kvm_intel module, the
  82  * callback function pointer will be assigned.
  83  *
  84  * protected by rcu.
  85  */
  86 crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
  87 EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
  88 unsigned long crash_zero_bytes;
  89
  90 static inline void cpu_crash_vmclear_loaded_vmcss(void)
  91 {
  92         crash_vmclear_fn *do_vmclear_operation = NULL;
  93
  94         rcu_read_lock();
  95         do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
  96         if (do_vmclear_operation)
  97                 do_vmclear_operation();
  98         rcu_read_unlock();
  99 }
 100
 101 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
 102
 103 static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
 104 {
 105 #ifdef CONFIG_X86_32
 106         struct pt_regs fixed_regs;
 107
 108         if (!user_mode(regs)) {
 109                 crash_fixup_ss_esp(&fixed_regs, regs);
 110                 regs = &fixed_regs;
 111         }
 112 #endif
 113         crash_save_cpu(regs, cpu);
 114
 115         /*
 116          * VMCLEAR VMCSs loaded on all cpus if needed.
 117          */
 118         cpu_crash_vmclear_loaded_vmcss();
 119
 120         /* Disable VMX or SVM if needed.
 121          *
 122          * We need to disable virtualization on all CPUs.
 123          * Having VMX or SVM enabled on any CPU may break rebooting
 124          * after the kdump kernel has finished its task.
 125          */
 126         cpu_emergency_vmxoff();
 127         cpu_emergency_svm_disable();
 128
 129         /*
 130          * Disable Intel PT to stop its logging
 131          */
 132         cpu_emergency_stop_pt();
 133
 134         disable_local_APIC();
 135 }
 136
 137 void kdump_nmi_shootdown_cpus(void)
 138 {
 139         nmi_shootdown_cpus(kdump_nmi_callback);
 140
 141         disable_local_APIC();
 142 }
 143
 144 /* Override the weak function in kernel/panic.c */
 145 void crash_smp_send_stop(void)
 146 {
 147         static int cpus_stopped;
 148
 149         if (cpus_stopped)
 150                 return;
 151
 152         if (smp_ops.crash_stop_other_cpus)
 153                 smp_ops.crash_stop_other_cpus();
 154         else
 155                 smp_send_stop();
 156
 157         cpus_stopped = 1;
 158 }
 159
 160 #else
 161 void crash_smp_send_stop(void)
 162 {
 163         /* There are no cpus to shootdown */
 164 }
 165 #endif
 166
 167 void native_machine_crash_shutdown(struct pt_regs *regs)
 168 {
 169         /* This function is only called after the system
 170          * has panicked or is otherwise in a critical state.
 171          * The minimum amount of code to allow a kexec'd kernel
 172          * to run successfully needs to happen here.
 173          *
 174          * In practice this means shooting down the other cpus in
 175          * an SMP system.
 176          */
 177         /* The kernel is broken so disable interrupts */
 178         local_irq_disable();
 179
 180         crash_smp_send_stop();
 181
 182         /*
 183          * VMCLEAR VMCSs loaded on this cpu if needed.
 184          */
 185         cpu_crash_vmclear_loaded_vmcss();
 186
 187         /* Booting kdump kernel with VMX or SVM enabled won't work,
 188          * because (among other limitations) we can't disable paging
 189          * with the virt flags.
 190          */
 191         cpu_emergency_vmxoff();
 192         cpu_emergency_svm_disable();
 193
 194         /*
 195          * Disable Intel PT to stop its logging
 196          */
 197         cpu_emergency_stop_pt();
 198
 199 #ifdef CONFIG_X86_IO_APIC
 200         /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
 201         ioapic_zap_locks();
 202         disable_IO_APIC();
 203 #endif
 204         lapic_shutdown();
 205 #ifdef CONFIG_HPET_TIMER
 206         hpet_disable();
 207 #endif
 208         crash_save_cpu(regs, safe_smp_processor_id());
 209 }
 210
 211 #ifdef CONFIG_KEXEC_FILE
 212 static int get_nr_ram_ranges_callback(u64 start, u64 end, void *arg)
 213 {
 214         unsigned int *nr_ranges = arg;
 215
 216         (*nr_ranges)++;
 217         return 0;
 218 }
 219
 220
 221 /* Gather all the required information to prepare elf headers for ram regions */
 222 static void fill_up_crash_elf_data(struct crash_elf_data *ced,
 223                                    struct kimage *image)
 224 {
 225         unsigned int nr_ranges = 0;
 226
 227         ced->image = image;
 228
 229         walk_system_ram_res(0, -1, &nr_ranges,
 230                                 get_nr_ram_ranges_callback);
 231
 232         ced->max_nr_ranges = nr_ranges;
 233
 234         /* Exclusion of crash region could split memory ranges */
 235         ced->max_nr_ranges++;
 236
 237         /* If crashk_low_res is not 0, another range split possible */
 238         if (crashk_low_res.end)
 239                 ced->max_nr_ranges++;
 240 }
 241
 242 static int exclude_mem_range(struct crash_mem *mem,
 243                 unsigned long long mstart, unsigned long long mend)
 244 {
 245         int i, j;
 246         unsigned long long start, end;
 247         struct crash_mem_range temp_range = {0, 0};
 248
 249         for (i = 0; i < mem->nr_ranges; i++) {
 250                 start = mem->ranges[i].start;
 251                 end = mem->ranges[i].end;
 252
 253                 if (mstart > end || mend < start)
 254                         continue;
 255
 256                 /* Truncate any area outside of range */
 257                 if (mstart < start)
 258                         mstart = start;
 259                 if (mend > end)
 260                         mend = end;
 261
 262                 /* Found completely overlapping range */
 263                 if (mstart == start && mend == end) {
 264                         mem->ranges[i].start = 0;
 265                         mem->ranges[i].end = 0;
 266                         if (i < mem->nr_ranges - 1) {
 267                                 /* Shift rest of the ranges to left */
 268                                 for (j = i; j < mem->nr_ranges - 1; j++) {
 269                                         mem->ranges[j].start =
 270                                                 mem->ranges[j+1].start;
 271                                         mem->ranges[j].end =
 272                                                         mem->ranges[j+1].end;
 273                                 }
 274                         }
 275                         mem->nr_ranges--;
 276                         return 0;
 277                 }
 278
 279                 if (mstart > start && mend < end) {
 280                         /* Split original range */
 281                         mem->ranges[i].end = mstart - 1;
 282                         temp_range.start = mend + 1;
 283                         temp_range.end = end;
 284                 } else if (mstart != start)
 285                         mem->ranges[i].end = mstart - 1;
 286                 else
 287                         mem->ranges[i].start = mend + 1;
 288                 break;
 289         }
 290
 291         /* If a split happend, add the split to array */
 292         if (!temp_range.end)
 293                 return 0;
 294
 295         /* Split happened */
 296         if (i == CRASH_MAX_RANGES - 1) {
 297                 pr_err("Too many crash ranges after split\n");
 298                 return -ENOMEM;
 299         }
 300
 301         /* Location where new range should go */
 302         j = i + 1;
 303         if (j < mem->nr_ranges) {
 304                 /* Move over all ranges one slot towards the end */
 305                 for (i = mem->nr_ranges - 1; i >= j; i--)
 306                         mem->ranges[i + 1] = mem->ranges[i];
 307         }
 308
 309         mem->ranges[j].start = temp_range.start;
 310         mem->ranges[j].end = temp_range.end;
 311         mem->nr_ranges++;
 312         return 0;
 313 }
 314
 315 /*
 316  * Look for any unwanted ranges between mstart, mend and remove them. This
 317  * might lead to split and split ranges are put in ced->mem.ranges[] array
 318  */
 319 static int elf_header_exclude_ranges(struct crash_elf_data *ced,
 320                 unsigned long long mstart, unsigned long long mend)
 321 {
 322         struct crash_mem *cmem = &ced->mem;
 323         int ret = 0;
 324
 325         memset(cmem->ranges, 0, sizeof(cmem->ranges));
 326
 327         cmem->ranges[0].start = mstart;
 328         cmem->ranges[0].end = mend;
 329         cmem->nr_ranges = 1;
 330
 331         /* Exclude crashkernel region */
 332         ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
 333         if (ret)
 334                 return ret;
 335
 336         if (crashk_low_res.end) {
 337                 ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
 338                 if (ret)
 339                         return ret;
 340         }
 341
 342         return ret;
 343 }
 344
 345 static int prepare_elf64_ram_headers_callback(u64 start, u64 end, void *arg)
 346 {
 347         struct crash_elf_data *ced = arg;
 348         Elf64_Ehdr *ehdr;
 349         Elf64_Phdr *phdr;
 350         unsigned long mstart, mend;
 351         struct kimage *image = ced->image;
 352         struct crash_mem *cmem;
 353         int ret, i;
 354
 355         ehdr = ced->ehdr;
 356
 357         /* Exclude unwanted mem ranges */
 358         ret = elf_header_exclude_ranges(ced, start, end);
 359         if (ret)
 360                 return ret;
 361
 362         /* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
 363         cmem = &ced->mem;
 364
 365         for (i = 0; i < cmem->nr_ranges; i++) {
 366                 mstart = cmem->ranges[i].start;
 367                 mend = cmem->ranges[i].end;
 368
 369                 phdr = ced->bufp;
 370                 ced->bufp += sizeof(Elf64_Phdr);
 371
 372                 phdr->p_type = PT_LOAD;
 373                 phdr->p_flags = PF_R|PF_W|PF_X;
 374                 phdr->p_offset  = mstart;
 375
 376                 /*
 377                  * If a range matches backup region, adjust offset to backup
 378                  * segment.
 379                  */
 380                 if (mstart == image->arch.backup_src_start &&
 381                     (mend - mstart + 1) == image->arch.backup_src_sz)
 382                         phdr->p_offset = image->arch.backup_load_addr;
 383
 384                 phdr->p_paddr = mstart;
 385                 phdr->p_vaddr = (unsigned long long) __va(mstart);
 386                 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
 387                 phdr->p_align = 0;
 388                 ehdr->e_phnum++;
 389                 pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
 390                         phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
 391                         ehdr->e_phnum, phdr->p_offset);
 392         }
 393
 394         return ret;
 395 }
 396
 397 static int prepare_elf64_headers(struct crash_elf_data *ced,
 398                 void **addr, unsigned long *sz)
 399 {
 400         Elf64_Ehdr *ehdr;
 401         Elf64_Phdr *phdr;
 402         unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
 403         unsigned char *buf, *bufp;
 404         unsigned int cpu;
 405         unsigned long long notes_addr;
 406         int ret;
 407
 408         /* extra phdr for vmcoreinfo elf note */
 409         nr_phdr = nr_cpus + 1;
 410         nr_phdr += ced->max_nr_ranges;
 411
 412         /*
 413          * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
 414          * area on x86_64 (ffffffff80000000 - ffffffffa0000000).
 415          * I think this is required by tools like gdb. So same physical
 416          * memory will be mapped in two elf headers. One will contain kernel
 417          * text virtual addresses and other will have __va(physical) addresses.
 418          */
 419
 420         nr_phdr++;
 421         elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
 422         elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
 423
 424         buf = vzalloc(elf_sz);
 425         if (!buf)
 426                 return -ENOMEM;
 427
 428         bufp = buf;
 429         ehdr = (Elf64_Ehdr *)bufp;
 430         bufp += sizeof(Elf64_Ehdr);
 431         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 432         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 433         ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
 434         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 435         ehdr->e_ident[EI_OSABI] = ELF_OSABI;
 436         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 437         ehdr->e_type = ET_CORE;
 438         ehdr->e_machine = ELF_ARCH;
 439         ehdr->e_version = EV_CURRENT;
 440         ehdr->e_phoff = sizeof(Elf64_Ehdr);
 441         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
 442         ehdr->e_phentsize = sizeof(Elf64_Phdr);
 443
 444         /* Prepare one phdr of type PT_NOTE for each present cpu */
 445         for_each_present_cpu(cpu) {
 446                 phdr = (Elf64_Phdr *)bufp;
 447                 bufp += sizeof(Elf64_Phdr);
 448                 phdr->p_type = PT_NOTE;
 449                 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
 450                 phdr->p_offset = phdr->p_paddr = notes_addr;
 451                 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
 452                 (ehdr->e_phnum)++;
 453         }
 454
 455         /* Prepare one PT_NOTE header for vmcoreinfo */
 456         phdr = (Elf64_Phdr *)bufp;
 457         bufp += sizeof(Elf64_Phdr);
 458         phdr->p_type = PT_NOTE;
 459         phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
 460         phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
 461         (ehdr->e_phnum)++;
 462
 463 #ifdef CONFIG_X86_64
 464         /* Prepare PT_LOAD type program header for kernel text region */
 465         phdr = (Elf64_Phdr *)bufp;
 466         bufp += sizeof(Elf64_Phdr);
 467         phdr->p_type = PT_LOAD;
 468         phdr->p_flags = PF_R|PF_W|PF_X;
 469         phdr->p_vaddr = (Elf64_Addr)_text;
 470         phdr->p_filesz = phdr->p_memsz = _end - _text;
 471         phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
 472         (ehdr->e_phnum)++;
 473 #endif
 474
 475         /* Prepare PT_LOAD headers for system ram chunks. */
 476         ced->ehdr = ehdr;
 477         ced->bufp = bufp;
 478         ret = walk_system_ram_res(0, -1, ced,
 479                         prepare_elf64_ram_headers_callback);
 480         if (ret < 0)
 481                 return ret;
 482
 483         *addr = buf;
 484         *sz = elf_sz;
 485         return 0;
 486 }
 487
 488 /* Prepare elf headers. Return addr and size */
 489 static int prepare_elf_headers(struct kimage *image, void **addr,
 490                                         unsigned long *sz)
 491 {
 492         struct crash_elf_data *ced;
 493         int ret;
 494
 495         ced = kzalloc(sizeof(*ced), GFP_KERNEL);
 496         if (!ced)
 497                 return -ENOMEM;
 498
 499         fill_up_crash_elf_data(ced, image);
 500
 501         /* By default prepare 64bit headers */
 502         ret =  prepare_elf64_headers(ced, addr, sz);
 503         kfree(ced);
 504         return ret;
 505 }
 506
 507 static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
 508 {
 509         unsigned int nr_e820_entries;
 510
 511         nr_e820_entries = params->e820_entries;
 512         if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
 513                 return 1;
 514
 515         memcpy(&params->e820_table[nr_e820_entries], entry,
 516                         sizeof(struct e820_entry));
 517         params->e820_entries++;
 518         return 0;
 519 }
 520
 521 static int memmap_entry_callback(u64 start, u64 end, void *arg)
 522 {
 523         struct crash_memmap_data *cmd = arg;
 524         struct boot_params *params = cmd->params;
 525         struct e820_entry ei;
 526
 527         ei.addr = start;
 528         ei.size = end - start + 1;
 529         ei.type = cmd->type;
 530         add_e820_entry(params, &ei);
 531
 532         return 0;
 533 }
 534
 535 static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
 536                                  unsigned long long mstart,
 537                                  unsigned long long mend)
 538 {
 539         unsigned long start, end;
 540         int ret = 0;
 541
 542         cmem->ranges[0].start = mstart;
 543         cmem->ranges[0].end = mend;
 544         cmem->nr_ranges = 1;
 545
 546         /* Exclude Backup region */
 547         start = image->arch.backup_load_addr;
 548         end = start + image->arch.backup_src_sz - 1;
 549         ret = exclude_mem_range(cmem, start, end);
 550         if (ret)
 551                 return ret;
 552
 553         /* Exclude elf header region */
 554         start = image->arch.elf_load_addr;
 555         end = start + image->arch.elf_headers_sz - 1;
 556         return exclude_mem_range(cmem, start, end);
 557 }
 558
 559 /* Prepare memory map for crash dump kernel */
 560 int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 561 {
 562         int i, ret = 0;
 563         unsigned long flags;
 564         struct e820_entry ei;
 565         struct crash_memmap_data cmd;
 566         struct crash_mem *cmem;
 567
 568         cmem = vzalloc(sizeof(struct crash_mem));
 569         if (!cmem)
 570                 return -ENOMEM;
 571
 572         memset(&cmd, 0, sizeof(struct crash_memmap_data));
 573         cmd.params = params;
 574
 575         /* Add first 640K segment */
 576         ei.addr = image->arch.backup_src_start;
 577         ei.size = image->arch.backup_src_sz;
 578         ei.type = E820_TYPE_RAM;
 579         add_e820_entry(params, &ei);
 580
 581         /* Add ACPI tables */
 582         cmd.type = E820_TYPE_ACPI;
 583         flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 584         walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
 585                        memmap_entry_callback);
 586
 587         /* Add ACPI Non-volatile Storage */
 588         cmd.type = E820_TYPE_NVS;
 589         walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
 590                         memmap_entry_callback);
 591
 592         /* Add crashk_low_res region */
 593         if (crashk_low_res.end) {
 594                 ei.addr = crashk_low_res.start;
 595                 ei.size = crashk_low_res.end - crashk_low_res.start + 1;
 596                 ei.type = E820_TYPE_RAM;
 597                 add_e820_entry(params, &ei);
 598         }
 599
 600         /* Exclude some ranges from crashk_res and add rest to memmap */
 601         ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
 602                                                 crashk_res.end);
 603         if (ret)
 604                 goto out;
 605
 606         for (i = 0; i < cmem->nr_ranges; i++) {
 607                 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
 608
 609                 /* If entry is less than a page, skip it */
 610                 if (ei.size < PAGE_SIZE)
 611                         continue;
 612                 ei.addr = cmem->ranges[i].start;
 613                 ei.type = E820_TYPE_RAM;
 614                 add_e820_entry(params, &ei);
 615         }
 616
 617 out:
 618         vfree(cmem);
 619         return ret;
 620 }
 621
 622 static int determine_backup_region(u64 start, u64 end, void *arg)
 623 {
 624         struct kimage *image = arg;
 625
 626         image->arch.backup_src_start = start;
 627         image->arch.backup_src_sz = end - start + 1;
 628
 629         /* Expecting only one range for backup region */
 630         return 1;
 631 }
 632
 633 int crash_load_segments(struct kimage *image)
 634 {
 635         int ret;
 636         struct kexec_buf kbuf = { .image = image, .buf_min = 0,
 637                                   .buf_max = ULONG_MAX, .top_down = false };
 638
 639         /*
 640          * Determine and load a segment for backup area. First 640K RAM
 641          * region is backup source
 642          */
 643
 644         ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
 645                                 image, determine_backup_region);
 646
 647         /* Zero or postive return values are ok */
 648         if (ret < 0)
 649                 return ret;
 650
 651         /* Add backup segment. */
 652         if (image->arch.backup_src_sz) {
 653                 kbuf.buffer = &crash_zero_bytes;
 654                 kbuf.bufsz = sizeof(crash_zero_bytes);
 655                 kbuf.memsz = image->arch.backup_src_sz;
 656                 kbuf.buf_align = PAGE_SIZE;
 657                 /*
 658                  * Ideally there is no source for backup segment. This is
 659                  * copied in purgatory after crash. Just add a zero filled
 660                  * segment for now to make sure checksum logic works fine.
 661                  */
 662                 ret = kexec_add_buffer(&kbuf);
 663                 if (ret)
 664                         return ret;
 665                 image->arch.backup_load_addr = kbuf.mem;
 666                 pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
 667                          image->arch.backup_load_addr,
 668                          image->arch.backup_src_start, kbuf.memsz);
 669         }
 670
 671         /* Prepare elf headers and add a segment */
 672         ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
 673         if (ret)
 674                 return ret;
 675
 676         image->arch.elf_headers = kbuf.buffer;
 677         image->arch.elf_headers_sz = kbuf.bufsz;
 678
 679         kbuf.memsz = kbuf.bufsz;
 680         kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
 681         ret = kexec_add_buffer(&kbuf);
 682         if (ret) {
 683                 vfree((void *)image->arch.elf_headers);
 684                 return ret;
 685         }
 686         image->arch.elf_load_addr = kbuf.mem;
 687         pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 688                  image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz);
 689
 690         return ret;
 691 }
 692 #endif /* CONFIG_KEXEC_FILE */