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/module.h>
  24 #include <linux/slab.h>
  25
  26 #include <asm/processor.h>
  27 #include <asm/hardirq.h>
  28 #include <asm/nmi.h>
  29 #include <asm/hw_irq.h>
  30 #include <asm/apic.h>
  31 #include <asm/hpet.h>
  32 #include <linux/kdebug.h>
  33 #include <asm/cpu.h>
  34 #include <asm/reboot.h>
  35 #include <asm/virtext.h>
  36
  37 /* Alignment required for elf header segment */
  38 #define ELF_CORE_HEADER_ALIGN   4096
  39
  40 /* This primarily represents number of split ranges due to exclusion */
  41 #define CRASH_MAX_RANGES        16
  42
  43 struct crash_mem_range {
  44         u64 start, end;
  45 };
  46
  47 struct crash_mem {
  48         unsigned int nr_ranges;
  49         struct crash_mem_range ranges[CRASH_MAX_RANGES];
  50 };
  51
  52 /* Misc data about ram ranges needed to prepare elf headers */
  53 struct crash_elf_data {
  54         struct kimage *image;
  55         /*
  56          * Total number of ram ranges we have after various adjustments for
  57          * GART, crash reserved region etc.
  58          */
  59         unsigned int max_nr_ranges;
  60         unsigned long gart_start, gart_end;
  61
  62         /* Pointer to elf header */
  63         void *ehdr;
  64         /* Pointer to next phdr */
  65         void *bufp;
  66         struct crash_mem mem;
  67 };
  68
  69 /* Used while preparing memory map entries for second kernel */
  70 struct crash_memmap_data {
  71         struct boot_params *params;
  72         /* Type of memory */
  73         unsigned int type;
  74 };
  75
  76 int in_crash_kexec;
  77
  78 /*
  79  * This is used to VMCLEAR all VMCSs loaded on the
  80  * processor. And when loading kvm_intel module, the
  81  * callback function pointer will be assigned.
  82  *
  83  * protected by rcu.
  84  */
  85 crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
  86 EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
  87 unsigned long crash_zero_bytes;
  88
  89 static inline void cpu_crash_vmclear_loaded_vmcss(void)
  90 {
  91         crash_vmclear_fn *do_vmclear_operation = NULL;
  92
  93         rcu_read_lock();
  94         do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
  95         if (do_vmclear_operation)
  96                 do_vmclear_operation();
  97         rcu_read_unlock();
  98 }
  99
 100 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
 101
 102 static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
 103 {
 104 #ifdef CONFIG_X86_32
 105         struct pt_regs fixed_regs;
 106
 107         if (!user_mode_vm(regs)) {
 108                 crash_fixup_ss_esp(&fixed_regs, regs);
 109                 regs = &fixed_regs;
 110         }
 111 #endif
 112         crash_save_cpu(regs, cpu);
 113
 114         /*
 115          * VMCLEAR VMCSs loaded on all cpus if needed.
 116          */
 117         cpu_crash_vmclear_loaded_vmcss();
 118
 119         /* Disable VMX or SVM if needed.
 120          *
 121          * We need to disable virtualization on all CPUs.
 122          * Having VMX or SVM enabled on any CPU may break rebooting
 123          * after the kdump kernel has finished its task.
 124          */
 125         cpu_emergency_vmxoff();
 126         cpu_emergency_svm_disable();
 127
 128         disable_local_APIC();
 129 }
 130
 131 static void kdump_nmi_shootdown_cpus(void)
 132 {
 133         in_crash_kexec = 1;
 134         nmi_shootdown_cpus(kdump_nmi_callback);
 135
 136         disable_local_APIC();
 137 }
 138
 139 #else
 140 static void kdump_nmi_shootdown_cpus(void)
 141 {
 142         /* There are no cpus to shootdown */
 143 }
 144 #endif
 145
 146 void native_machine_crash_shutdown(struct pt_regs *regs)
 147 {
 148         /* This function is only called after the system
 149          * has panicked or is otherwise in a critical state.
 150          * The minimum amount of code to allow a kexec'd kernel
 151          * to run successfully needs to happen here.
 152          *
 153          * In practice this means shooting down the other cpus in
 154          * an SMP system.
 155          */
 156         /* The kernel is broken so disable interrupts */
 157         local_irq_disable();
 158
 159         kdump_nmi_shootdown_cpus();
 160
 161         /*
 162          * VMCLEAR VMCSs loaded on this cpu if needed.
 163          */
 164         cpu_crash_vmclear_loaded_vmcss();
 165
 166         /* Booting kdump kernel with VMX or SVM enabled won't work,
 167          * because (among other limitations) we can't disable paging
 168          * with the virt flags.
 169          */
 170         cpu_emergency_vmxoff();
 171         cpu_emergency_svm_disable();
 172
 173 #ifdef CONFIG_X86_IO_APIC
 174         /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
 175         ioapic_zap_locks();
 176         disable_IO_APIC();
 177 #endif
 178         lapic_shutdown();
 179 #ifdef CONFIG_HPET_TIMER
 180         hpet_disable();
 181 #endif
 182         crash_save_cpu(regs, safe_smp_processor_id());
 183 }
 184
 185 #ifdef CONFIG_X86_64
 186
 187 static int get_nr_ram_ranges_callback(unsigned long start_pfn,
 188                                 unsigned long nr_pfn, void *arg)
 189 {
 190         int *nr_ranges = arg;
 191
 192         (*nr_ranges)++;
 193         return 0;
 194 }
 195
 196 static int get_gart_ranges_callback(u64 start, u64 end, void *arg)
 197 {
 198         struct crash_elf_data *ced = arg;
 199
 200         ced->gart_start = start;
 201         ced->gart_end = end;
 202
 203         /* Not expecting more than 1 gart aperture */
 204         return 1;
 205 }
 206
 207
 208 /* Gather all the required information to prepare elf headers for ram regions */
 209 static void fill_up_crash_elf_data(struct crash_elf_data *ced,
 210                                    struct kimage *image)
 211 {
 212         unsigned int nr_ranges = 0;
 213
 214         ced->image = image;
 215
 216         walk_system_ram_range(0, -1, &nr_ranges,
 217                                 get_nr_ram_ranges_callback);
 218
 219         ced->max_nr_ranges = nr_ranges;
 220
 221         /*
 222          * We don't create ELF headers for GART aperture as an attempt
 223          * to dump this memory in second kernel leads to hang/crash.
 224          * If gart aperture is present, one needs to exclude that region
 225          * and that could lead to need of extra phdr.
 226          */
 227         walk_iomem_res("GART", IORESOURCE_MEM, 0, -1,
 228                                 ced, get_gart_ranges_callback);
 229
 230         /*
 231          * If we have gart region, excluding that could potentially split
 232          * a memory range, resulting in extra header. Account for  that.
 233          */
 234         if (ced->gart_end)
 235                 ced->max_nr_ranges++;
 236
 237         /* Exclusion of crash region could split memory ranges */
 238         ced->max_nr_ranges++;
 239
 240         /* If crashk_low_res is not 0, another range split possible */
 241         if (crashk_low_res.end != 0)
 242                 ced->max_nr_ranges++;
 243 }
 244
 245 static int exclude_mem_range(struct crash_mem *mem,
 246                 unsigned long long mstart, unsigned long long mend)
 247 {
 248         int i, j;
 249         unsigned long long start, end;
 250         struct crash_mem_range temp_range = {0, 0};
 251
 252         for (i = 0; i < mem->nr_ranges; i++) {
 253                 start = mem->ranges[i].start;
 254                 end = mem->ranges[i].end;
 255
 256                 if (mstart > end || mend < start)
 257                         continue;
 258
 259                 /* Truncate any area outside of range */
 260                 if (mstart < start)
 261                         mstart = start;
 262                 if (mend > end)
 263                         mend = end;
 264
 265                 /* Found completely overlapping range */
 266                 if (mstart == start && mend == end) {
 267                         mem->ranges[i].start = 0;
 268                         mem->ranges[i].end = 0;
 269                         if (i < mem->nr_ranges - 1) {
 270                                 /* Shift rest of the ranges to left */
 271                                 for (j = i; j < mem->nr_ranges - 1; j++) {
 272                                         mem->ranges[j].start =
 273                                                 mem->ranges[j+1].start;
 274                                         mem->ranges[j].end =
 275                                                         mem->ranges[j+1].end;
 276                                 }
 277                         }
 278                         mem->nr_ranges--;
 279                         return 0;
 280                 }
 281
 282                 if (mstart > start && mend < end) {
 283                         /* Split original range */
 284                         mem->ranges[i].end = mstart - 1;
 285                         temp_range.start = mend + 1;
 286                         temp_range.end = end;
 287                 } else if (mstart != start)
 288                         mem->ranges[i].end = mstart - 1;
 289                 else
 290                         mem->ranges[i].start = mend + 1;
 291                 break;
 292         }
 293
 294         /* If a split happend, add the split to array */
 295         if (!temp_range.end)
 296                 return 0;
 297
 298         /* Split happened */
 299         if (i == CRASH_MAX_RANGES - 1) {
 300                 pr_err("Too many crash ranges after split\n");
 301                 return -ENOMEM;
 302         }
 303
 304         /* Location where new range should go */
 305         j = i + 1;
 306         if (j < mem->nr_ranges) {
 307                 /* Move over all ranges one slot towards the end */
 308                 for (i = mem->nr_ranges - 1; i >= j; i--)
 309                         mem->ranges[i + 1] = mem->ranges[i];
 310         }
 311
 312         mem->ranges[j].start = temp_range.start;
 313         mem->ranges[j].end = temp_range.end;
 314         mem->nr_ranges++;
 315         return 0;
 316 }
 317
 318 /*
 319  * Look for any unwanted ranges between mstart, mend and remove them. This
 320  * might lead to split and split ranges are put in ced->mem.ranges[] array
 321  */
 322 static int elf_header_exclude_ranges(struct crash_elf_data *ced,
 323                 unsigned long long mstart, unsigned long long mend)
 324 {
 325         struct crash_mem *cmem = &ced->mem;
 326         int ret = 0;
 327
 328         memset(cmem->ranges, 0, sizeof(cmem->ranges));
 329
 330         cmem->ranges[0].start = mstart;
 331         cmem->ranges[0].end = mend;
 332         cmem->nr_ranges = 1;
 333
 334         /* Exclude crashkernel region */
 335         ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
 336         if (ret)
 337                 return ret;
 338
 339         ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
 340         if (ret)
 341                 return ret;
 342
 343         /* Exclude GART region */
 344         if (ced->gart_end) {
 345                 ret = exclude_mem_range(cmem, ced->gart_start, ced->gart_end);
 346                 if (ret)
 347                         return ret;
 348         }
 349
 350         return ret;
 351 }
 352
 353 static int prepare_elf64_ram_headers_callback(u64 start, u64 end, void *arg)
 354 {
 355         struct crash_elf_data *ced = arg;
 356         Elf64_Ehdr *ehdr;
 357         Elf64_Phdr *phdr;
 358         unsigned long mstart, mend;
 359         struct kimage *image = ced->image;
 360         struct crash_mem *cmem;
 361         int ret, i;
 362
 363         ehdr = ced->ehdr;
 364
 365         /* Exclude unwanted mem ranges */
 366         ret = elf_header_exclude_ranges(ced, start, end);
 367         if (ret)
 368                 return ret;
 369
 370         /* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
 371         cmem = &ced->mem;
 372
 373         for (i = 0; i < cmem->nr_ranges; i++) {
 374                 mstart = cmem->ranges[i].start;
 375                 mend = cmem->ranges[i].end;
 376
 377                 phdr = ced->bufp;
 378                 ced->bufp += sizeof(Elf64_Phdr);
 379
 380                 phdr->p_type = PT_LOAD;
 381                 phdr->p_flags = PF_R|PF_W|PF_X;
 382                 phdr->p_offset  = mstart;
 383
 384                 /*
 385                  * If a range matches backup region, adjust offset to backup
 386                  * segment.
 387                  */
 388                 if (mstart == image->arch.backup_src_start &&
 389                     (mend - mstart + 1) == image->arch.backup_src_sz)
 390                         phdr->p_offset = image->arch.backup_load_addr;
 391
 392                 phdr->p_paddr = mstart;
 393                 phdr->p_vaddr = (unsigned long long) __va(mstart);
 394                 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
 395                 phdr->p_align = 0;
 396                 ehdr->e_phnum++;
 397                 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",
 398                         phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
 399                         ehdr->e_phnum, phdr->p_offset);
 400         }
 401
 402         return ret;
 403 }
 404
 405 static int prepare_elf64_headers(struct crash_elf_data *ced,
 406                 void **addr, unsigned long *sz)
 407 {
 408         Elf64_Ehdr *ehdr;
 409         Elf64_Phdr *phdr;
 410         unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
 411         unsigned char *buf, *bufp;
 412         unsigned int cpu;
 413         unsigned long long notes_addr;
 414         int ret;
 415
 416         /* extra phdr for vmcoreinfo elf note */
 417         nr_phdr = nr_cpus + 1;
 418         nr_phdr += ced->max_nr_ranges;
 419
 420         /*
 421          * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
 422          * area on x86_64 (ffffffff80000000 - ffffffffa0000000).
 423          * I think this is required by tools like gdb. So same physical
 424          * memory will be mapped in two elf headers. One will contain kernel
 425          * text virtual addresses and other will have __va(physical) addresses.
 426          */
 427
 428         nr_phdr++;
 429         elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
 430         elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
 431
 432         buf = vzalloc(elf_sz);
 433         if (!buf)
 434                 return -ENOMEM;
 435
 436         bufp = buf;
 437         ehdr = (Elf64_Ehdr *)bufp;
 438         bufp += sizeof(Elf64_Ehdr);
 439         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 440         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 441         ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
 442         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 443         ehdr->e_ident[EI_OSABI] = ELF_OSABI;
 444         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 445         ehdr->e_type = ET_CORE;
 446         ehdr->e_machine = ELF_ARCH;
 447         ehdr->e_version = EV_CURRENT;
 448         ehdr->e_phoff = sizeof(Elf64_Ehdr);
 449         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
 450         ehdr->e_phentsize = sizeof(Elf64_Phdr);
 451
 452         /* Prepare one phdr of type PT_NOTE for each present cpu */
 453         for_each_present_cpu(cpu) {
 454                 phdr = (Elf64_Phdr *)bufp;
 455                 bufp += sizeof(Elf64_Phdr);
 456                 phdr->p_type = PT_NOTE;
 457                 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
 458                 phdr->p_offset = phdr->p_paddr = notes_addr;
 459                 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
 460                 (ehdr->e_phnum)++;
 461         }
 462
 463         /* Prepare one PT_NOTE header for vmcoreinfo */
 464         phdr = (Elf64_Phdr *)bufp;
 465         bufp += sizeof(Elf64_Phdr);
 466         phdr->p_type = PT_NOTE;
 467         phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
 468         phdr->p_filesz = phdr->p_memsz = sizeof(vmcoreinfo_note);
 469         (ehdr->e_phnum)++;
 470
 471 #ifdef CONFIG_X86_64
 472         /* Prepare PT_LOAD type program header for kernel text region */
 473         phdr = (Elf64_Phdr *)bufp;
 474         bufp += sizeof(Elf64_Phdr);
 475         phdr->p_type = PT_LOAD;
 476         phdr->p_flags = PF_R|PF_W|PF_X;
 477         phdr->p_vaddr = (Elf64_Addr)_text;
 478         phdr->p_filesz = phdr->p_memsz = _end - _text;
 479         phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
 480         (ehdr->e_phnum)++;
 481 #endif
 482
 483         /* Prepare PT_LOAD headers for system ram chunks. */
 484         ced->ehdr = ehdr;
 485         ced->bufp = bufp;
 486         ret = walk_system_ram_res(0, -1, ced,
 487                         prepare_elf64_ram_headers_callback);
 488         if (ret < 0)
 489                 return ret;
 490
 491         *addr = buf;
 492         *sz = elf_sz;
 493         return 0;
 494 }
 495
 496 /* Prepare elf headers. Return addr and size */
 497 static int prepare_elf_headers(struct kimage *image, void **addr,
 498                                         unsigned long *sz)
 499 {
 500         struct crash_elf_data *ced;
 501         int ret;
 502
 503         ced = kzalloc(sizeof(*ced), GFP_KERNEL);
 504         if (!ced)
 505                 return -ENOMEM;
 506
 507         fill_up_crash_elf_data(ced, image);
 508
 509         /* By default prepare 64bit headers */
 510         ret =  prepare_elf64_headers(ced, addr, sz);
 511         kfree(ced);
 512         return ret;
 513 }
 514
 515 static int add_e820_entry(struct boot_params *params, struct e820entry *entry)
 516 {
 517         unsigned int nr_e820_entries;
 518
 519         nr_e820_entries = params->e820_entries;
 520         if (nr_e820_entries >= E820MAX)
 521                 return 1;
 522
 523         memcpy(&params->e820_map[nr_e820_entries], entry,
 524                         sizeof(struct e820entry));
 525         params->e820_entries++;
 526         return 0;
 527 }
 528
 529 static int memmap_entry_callback(u64 start, u64 end, void *arg)
 530 {
 531         struct crash_memmap_data *cmd = arg;
 532         struct boot_params *params = cmd->params;
 533         struct e820entry ei;
 534
 535         ei.addr = start;
 536         ei.size = end - start + 1;
 537         ei.type = cmd->type;
 538         add_e820_entry(params, &ei);
 539
 540         return 0;
 541 }
 542
 543 static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
 544                                  unsigned long long mstart,
 545                                  unsigned long long mend)
 546 {
 547         unsigned long start, end;
 548         int ret = 0;
 549
 550         cmem->ranges[0].start = mstart;
 551         cmem->ranges[0].end = mend;
 552         cmem->nr_ranges = 1;
 553
 554         /* Exclude Backup region */
 555         start = image->arch.backup_load_addr;
 556         end = start + image->arch.backup_src_sz - 1;
 557         ret = exclude_mem_range(cmem, start, end);
 558         if (ret)
 559                 return ret;
 560
 561         /* Exclude elf header region */
 562         start = image->arch.elf_load_addr;
 563         end = start + image->arch.elf_headers_sz - 1;
 564         return exclude_mem_range(cmem, start, end);
 565 }
 566
 567 /* Prepare memory map for crash dump kernel */
 568 int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 569 {
 570         int i, ret = 0;
 571         unsigned long flags;
 572         struct e820entry ei;
 573         struct crash_memmap_data cmd;
 574         struct crash_mem *cmem;
 575
 576         cmem = vzalloc(sizeof(struct crash_mem));
 577         if (!cmem)
 578                 return -ENOMEM;
 579
 580         memset(&cmd, 0, sizeof(struct crash_memmap_data));
 581         cmd.params = params;
 582
 583         /* Add first 640K segment */
 584         ei.addr = image->arch.backup_src_start;
 585         ei.size = image->arch.backup_src_sz;
 586         ei.type = E820_RAM;
 587         add_e820_entry(params, &ei);
 588
 589         /* Add ACPI tables */
 590         cmd.type = E820_ACPI;
 591         flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 592         walk_iomem_res("ACPI Tables", flags, 0, -1, &cmd,
 593                        memmap_entry_callback);
 594
 595         /* Add ACPI Non-volatile Storage */
 596         cmd.type = E820_NVS;
 597         walk_iomem_res("ACPI Non-volatile Storage", flags, 0, -1, &cmd,
 598                         memmap_entry_callback);
 599
 600         /* Add crashk_low_res region */
 601         if (crashk_low_res.end) {
 602                 ei.addr = crashk_low_res.start;
 603                 ei.size = crashk_low_res.end - crashk_low_res.start + 1;
 604                 ei.type = E820_RAM;
 605                 add_e820_entry(params, &ei);
 606         }
 607
 608         /* Exclude some ranges from crashk_res and add rest to memmap */
 609         ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
 610                                                 crashk_res.end);
 611         if (ret)
 612                 goto out;
 613
 614         for (i = 0; i < cmem->nr_ranges; i++) {
 615                 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
 616
 617                 /* If entry is less than a page, skip it */
 618                 if (ei.size < PAGE_SIZE)
 619                         continue;
 620                 ei.addr = cmem->ranges[i].start;
 621                 ei.type = E820_RAM;
 622                 add_e820_entry(params, &ei);
 623         }
 624
 625 out:
 626         vfree(cmem);
 627         return ret;
 628 }
 629
 630 static int determine_backup_region(u64 start, u64 end, void *arg)
 631 {
 632         struct kimage *image = arg;
 633
 634         image->arch.backup_src_start = start;
 635         image->arch.backup_src_sz = end - start + 1;
 636
 637         /* Expecting only one range for backup region */
 638         return 1;
 639 }
 640
 641 int crash_load_segments(struct kimage *image)
 642 {
 643         unsigned long src_start, src_sz, elf_sz;
 644         void *elf_addr;
 645         int ret;
 646
 647         /*
 648          * Determine and load a segment for backup area. First 640K RAM
 649          * region is backup source
 650          */
 651
 652         ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
 653                                 image, determine_backup_region);
 654
 655         /* Zero or postive return values are ok */
 656         if (ret < 0)
 657                 return ret;
 658
 659         src_start = image->arch.backup_src_start;
 660         src_sz = image->arch.backup_src_sz;
 661
 662         /* Add backup segment. */
 663         if (src_sz) {
 664                 /*
 665                  * Ideally there is no source for backup segment. This is
 666                  * copied in purgatory after crash. Just add a zero filled
 667                  * segment for now to make sure checksum logic works fine.
 668                  */
 669                 ret = kexec_add_buffer(image, (char *)&crash_zero_bytes,
 670                                        sizeof(crash_zero_bytes), src_sz,
 671                                        PAGE_SIZE, 0, -1, 0,
 672                                        &image->arch.backup_load_addr);
 673                 if (ret)
 674                         return ret;
 675                 pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
 676                          image->arch.backup_load_addr, src_start, src_sz);
 677         }
 678
 679         /* Prepare elf headers and add a segment */
 680         ret = prepare_elf_headers(image, &elf_addr, &elf_sz);
 681         if (ret)
 682                 return ret;
 683
 684         image->arch.elf_headers = elf_addr;
 685         image->arch.elf_headers_sz = elf_sz;
 686
 687         ret = kexec_add_buffer(image, (char *)elf_addr, elf_sz, elf_sz,
 688                         ELF_CORE_HEADER_ALIGN, 0, -1, 0,
 689                         &image->arch.elf_load_addr);
 690         if (ret) {
 691                 vfree((void *)image->arch.elf_headers);
 692                 return ret;
 693         }
 694         pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 695                  image->arch.elf_load_addr, elf_sz, elf_sz);
 696
 697         return ret;
 698 }
 699
 700 #endif /* CONFIG_X86_64 */