arch/s390/kernel/crash_dump.c

   1 /*
   2  * S390 kdump implementation
   3  *
   4  * Copyright IBM Corp. 2011
   5  * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
   6  */
   7
   8 #include <linux/crash_dump.h>
   9 #include <asm/lowcore.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/gfp.h>
  13 #include <linux/slab.h>
  14 #include <linux/bootmem.h>
  15 #include <linux/elf.h>
  16 #include <linux/memblock.h>
  17 #include <asm/os_info.h>
  18 #include <asm/elf.h>
  19 #include <asm/ipl.h>
  20 #include <asm/sclp.h>
  21
  22 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
  23 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
  24 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
  25
  26 static struct memblock_region oldmem_region;
  27
  28 static struct memblock_type oldmem_type = {
  29         .cnt = 1,
  30         .max = 1,
  31         .total_size = 0,
  32         .regions = &oldmem_region,
  33 };
  34
  35 #define for_each_dump_mem_range(i, nid, p_start, p_end, p_nid)          \
  36         for (i = 0, __next_mem_range(&i, nid, &memblock.physmem,        \
  37                                      &oldmem_type, p_start,             \
  38                                      p_end, p_nid);                     \
  39              i != (u64)ULLONG_MAX;                                      \
  40              __next_mem_range(&i, nid, &memblock.physmem,               \
  41                               &oldmem_type,                             \
  42                               p_start, p_end, p_nid))
  43
  44 struct dump_save_areas dump_save_areas;
  45
  46 /*
  47  * Allocate and add a save area for a CPU
  48  */
  49 struct save_area_ext *dump_save_area_create(int cpu)
  50 {
  51         struct save_area_ext **save_areas, *save_area;
  52
  53         save_area = kmalloc(sizeof(*save_area), GFP_KERNEL);
  54         if (!save_area)
  55                 return NULL;
  56         if (cpu + 1 > dump_save_areas.count) {
  57                 dump_save_areas.count = cpu + 1;
  58                 save_areas = krealloc(dump_save_areas.areas,
  59                                       dump_save_areas.count * sizeof(void *),
  60                                       GFP_KERNEL | __GFP_ZERO);
  61                 if (!save_areas) {
  62                         kfree(save_area);
  63                         return NULL;
  64                 }
  65                 dump_save_areas.areas = save_areas;
  66         }
  67         dump_save_areas.areas[cpu] = save_area;
  68         return save_area;
  69 }
  70
  71 /*
  72  * Return physical address for virtual address
  73  */
  74 static inline void *load_real_addr(void *addr)
  75 {
  76         unsigned long real_addr;
  77
  78         asm volatile(
  79                    "    lra     %0,0(%1)\n"
  80                    "    jz      0f\n"
  81                    "    la      %0,0\n"
  82                    "0:"
  83                    : "=a" (real_addr) : "a" (addr) : "cc");
  84         return (void *)real_addr;
  85 }
  86
  87 /*
  88  * Copy real to virtual or real memory
  89  */
  90 static int copy_from_realmem(void *dest, void *src, size_t count)
  91 {
  92         unsigned long size;
  93
  94         if (!count)
  95                 return 0;
  96         if (!is_vmalloc_or_module_addr(dest))
  97                 return memcpy_real(dest, src, count);
  98         do {
  99                 size = min(count, PAGE_SIZE - (__pa(dest) & ~PAGE_MASK));
 100                 if (memcpy_real(load_real_addr(dest), src, size))
 101                         return -EFAULT;
 102                 count -= size;
 103                 dest += size;
 104                 src += size;
 105         } while (count);
 106         return 0;
 107 }
 108
 109 /*
 110  * Pointer to ELF header in new kernel
 111  */
 112 static void *elfcorehdr_newmem;
 113
 114 /*
 115  * Copy one page from zfcpdump "oldmem"
 116  *
 117  * For pages below HSA size memory from the HSA is copied. Otherwise
 118  * real memory copy is used.
 119  */
 120 static ssize_t copy_oldmem_page_zfcpdump(char *buf, size_t csize,
 121                                          unsigned long src, int userbuf)
 122 {
 123         int rc;
 124
 125         if (src < sclp_get_hsa_size()) {
 126                 rc = memcpy_hsa(buf, src, csize, userbuf);
 127         } else {
 128                 if (userbuf)
 129                         rc = copy_to_user_real((void __force __user *) buf,
 130                                                (void *) src, csize);
 131                 else
 132                         rc = memcpy_real(buf, (void *) src, csize);
 133         }
 134         return rc ? rc : csize;
 135 }
 136
 137 /*
 138  * Copy one page from kdump "oldmem"
 139  *
 140  * For the kdump reserved memory this functions performs a swap operation:
 141  *  - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE].
 142  *  - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
 143  */
 144 static ssize_t copy_oldmem_page_kdump(char *buf, size_t csize,
 145                                       unsigned long src, int userbuf)
 146
 147 {
 148         int rc;
 149
 150         if (src < OLDMEM_SIZE)
 151                 src += OLDMEM_BASE;
 152         else if (src > OLDMEM_BASE &&
 153                  src < OLDMEM_BASE + OLDMEM_SIZE)
 154                 src -= OLDMEM_BASE;
 155         if (userbuf)
 156                 rc = copy_to_user_real((void __force __user *) buf,
 157                                        (void *) src, csize);
 158         else
 159                 rc = copy_from_realmem(buf, (void *) src, csize);
 160         return (rc == 0) ? rc : csize;
 161 }
 162
 163 /*
 164  * Copy one page from "oldmem"
 165  */
 166 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
 167                          unsigned long offset, int userbuf)
 168 {
 169         unsigned long src;
 170
 171         if (!csize)
 172                 return 0;
 173         src = (pfn << PAGE_SHIFT) + offset;
 174         if (OLDMEM_BASE)
 175                 return copy_oldmem_page_kdump(buf, csize, src, userbuf);
 176         else
 177                 return copy_oldmem_page_zfcpdump(buf, csize, src, userbuf);
 178 }
 179
 180 /*
 181  * Remap "oldmem" for kdump
 182  *
 183  * For the kdump reserved memory this functions performs a swap operation:
 184  * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
 185  */
 186 static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
 187                                         unsigned long from, unsigned long pfn,
 188                                         unsigned long size, pgprot_t prot)
 189 {
 190         unsigned long size_old;
 191         int rc;
 192
 193         if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
 194                 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
 195                 rc = remap_pfn_range(vma, from,
 196                                      pfn + (OLDMEM_BASE >> PAGE_SHIFT),
 197                                      size_old, prot);
 198                 if (rc || size == size_old)
 199                         return rc;
 200                 size -= size_old;
 201                 from += size_old;
 202                 pfn += size_old >> PAGE_SHIFT;
 203         }
 204         return remap_pfn_range(vma, from, pfn, size, prot);
 205 }
 206
 207 /*
 208  * Remap "oldmem" for zfcpdump
 209  *
 210  * We only map available memory above HSA size. Memory below HSA size
 211  * is read on demand using the copy_oldmem_page() function.
 212  */
 213 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
 214                                            unsigned long from,
 215                                            unsigned long pfn,
 216                                            unsigned long size, pgprot_t prot)
 217 {
 218         unsigned long hsa_end = sclp_get_hsa_size();
 219         unsigned long size_hsa;
 220
 221         if (pfn < hsa_end >> PAGE_SHIFT) {
 222                 size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
 223                 if (size == size_hsa)
 224                         return 0;
 225                 size -= size_hsa;
 226                 from += size_hsa;
 227                 pfn += size_hsa >> PAGE_SHIFT;
 228         }
 229         return remap_pfn_range(vma, from, pfn, size, prot);
 230 }
 231
 232 /*
 233  * Remap "oldmem" for kdump or zfcpdump
 234  */
 235 int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
 236                            unsigned long pfn, unsigned long size, pgprot_t prot)
 237 {
 238         if (OLDMEM_BASE)
 239                 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
 240         else
 241                 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
 242                                                        prot);
 243 }
 244
 245 /*
 246  * Copy memory from old kernel
 247  */
 248 int copy_from_oldmem(void *dest, void *src, size_t count)
 249 {
 250         unsigned long copied = 0;
 251         int rc;
 252
 253         if (OLDMEM_BASE) {
 254                 if ((unsigned long) src < OLDMEM_SIZE) {
 255                         copied = min(count, OLDMEM_SIZE - (unsigned long) src);
 256                         rc = copy_from_realmem(dest, src + OLDMEM_BASE, copied);
 257                         if (rc)
 258                                 return rc;
 259                 }
 260         } else {
 261                 unsigned long hsa_end = sclp_get_hsa_size();
 262                 if ((unsigned long) src < hsa_end) {
 263                         copied = min(count, hsa_end - (unsigned long) src);
 264                         rc = memcpy_hsa(dest, (unsigned long) src, copied, 0);
 265                         if (rc)
 266                                 return rc;
 267                 }
 268         }
 269         return copy_from_realmem(dest + copied, src + copied, count - copied);
 270 }
 271
 272 /*
 273  * Alloc memory and panic in case of ENOMEM
 274  */
 275 static void *kzalloc_panic(int len)
 276 {
 277         void *rc;
 278
 279         rc = kzalloc(len, GFP_KERNEL);
 280         if (!rc)
 281                 panic("s390 kdump kzalloc (%d) failed", len);
 282         return rc;
 283 }
 284
 285 /*
 286  * Initialize ELF note
 287  */
 288 static void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len,
 289                      const char *name)
 290 {
 291         Elf64_Nhdr *note;
 292         u64 len;
 293
 294         note = (Elf64_Nhdr *)buf;
 295         note->n_namesz = strlen(name) + 1;
 296         note->n_descsz = d_len;
 297         note->n_type = type;
 298         len = sizeof(Elf64_Nhdr);
 299
 300         memcpy(buf + len, name, note->n_namesz);
 301         len = roundup(len + note->n_namesz, 4);
 302
 303         memcpy(buf + len, desc, note->n_descsz);
 304         len = roundup(len + note->n_descsz, 4);
 305
 306         return PTR_ADD(buf, len);
 307 }
 308
 309 /*
 310  * Initialize prstatus note
 311  */
 312 static void *nt_prstatus(void *ptr, struct save_area *sa)
 313 {
 314         struct elf_prstatus nt_prstatus;
 315         static int cpu_nr = 1;
 316
 317         memset(&nt_prstatus, 0, sizeof(nt_prstatus));
 318         memcpy(&nt_prstatus.pr_reg.gprs, sa->gp_regs, sizeof(sa->gp_regs));
 319         memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
 320         memcpy(&nt_prstatus.pr_reg.acrs, sa->acc_regs, sizeof(sa->acc_regs));
 321         nt_prstatus.pr_pid = cpu_nr;
 322         cpu_nr++;
 323
 324         return nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus),
 325                          "CORE");
 326 }
 327
 328 /*
 329  * Initialize fpregset (floating point) note
 330  */
 331 static void *nt_fpregset(void *ptr, struct save_area *sa)
 332 {
 333         elf_fpregset_t nt_fpregset;
 334
 335         memset(&nt_fpregset, 0, sizeof(nt_fpregset));
 336         memcpy(&nt_fpregset.fpc, &sa->fp_ctrl_reg, sizeof(sa->fp_ctrl_reg));
 337         memcpy(&nt_fpregset.fprs, &sa->fp_regs, sizeof(sa->fp_regs));
 338
 339         return nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset),
 340                        "CORE");
 341 }
 342
 343 /*
 344  * Initialize timer note
 345  */
 346 static void *nt_s390_timer(void *ptr, struct save_area *sa)
 347 {
 348         return nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer),
 349                          KEXEC_CORE_NOTE_NAME);
 350 }
 351
 352 /*
 353  * Initialize TOD clock comparator note
 354  */
 355 static void *nt_s390_tod_cmp(void *ptr, struct save_area *sa)
 356 {
 357         return nt_init(ptr, NT_S390_TODCMP, &sa->clk_cmp,
 358                        sizeof(sa->clk_cmp), KEXEC_CORE_NOTE_NAME);
 359 }
 360
 361 /*
 362  * Initialize TOD programmable register note
 363  */
 364 static void *nt_s390_tod_preg(void *ptr, struct save_area *sa)
 365 {
 366         return nt_init(ptr, NT_S390_TODPREG, &sa->tod_reg,
 367                        sizeof(sa->tod_reg), KEXEC_CORE_NOTE_NAME);
 368 }
 369
 370 /*
 371  * Initialize control register note
 372  */
 373 static void *nt_s390_ctrs(void *ptr, struct save_area *sa)
 374 {
 375         return nt_init(ptr, NT_S390_CTRS, &sa->ctrl_regs,
 376                        sizeof(sa->ctrl_regs), KEXEC_CORE_NOTE_NAME);
 377 }
 378
 379 /*
 380  * Initialize prefix register note
 381  */
 382 static void *nt_s390_prefix(void *ptr, struct save_area *sa)
 383 {
 384         return nt_init(ptr, NT_S390_PREFIX, &sa->pref_reg,
 385                          sizeof(sa->pref_reg), KEXEC_CORE_NOTE_NAME);
 386 }
 387
 388 /*
 389  * Initialize vxrs high note (full 128 bit VX registers 16-31)
 390  */
 391 static void *nt_s390_vx_high(void *ptr, __vector128 *vx_regs)
 392 {
 393         return nt_init(ptr, NT_S390_VXRS_HIGH, &vx_regs[16],
 394                        16 * sizeof(__vector128), KEXEC_CORE_NOTE_NAME);
 395 }
 396
 397 /*
 398  * Initialize vxrs low note (lower halves of VX registers 0-15)
 399  */
 400 static void *nt_s390_vx_low(void *ptr, __vector128 *vx_regs)
 401 {
 402         Elf64_Nhdr *note;
 403         u64 len;
 404         int i;
 405
 406         note = (Elf64_Nhdr *)ptr;
 407         note->n_namesz = strlen(KEXEC_CORE_NOTE_NAME) + 1;
 408         note->n_descsz = 16 * 8;
 409         note->n_type = NT_S390_VXRS_LOW;
 410         len = sizeof(Elf64_Nhdr);
 411
 412         memcpy(ptr + len, KEXEC_CORE_NOTE_NAME, note->n_namesz);
 413         len = roundup(len + note->n_namesz, 4);
 414
 415         ptr += len;
 416         /* Copy lower halves of SIMD registers 0-15 */
 417         for (i = 0; i < 16; i++) {
 418                 memcpy(ptr, &vx_regs[i], 8);
 419                 ptr += 8;
 420         }
 421         return ptr;
 422 }
 423
 424 /*
 425  * Fill ELF notes for one CPU with save area registers
 426  */
 427 void *fill_cpu_elf_notes(void *ptr, struct save_area *sa, __vector128 *vx_regs)
 428 {
 429         ptr = nt_prstatus(ptr, sa);
 430         ptr = nt_fpregset(ptr, sa);
 431         ptr = nt_s390_timer(ptr, sa);
 432         ptr = nt_s390_tod_cmp(ptr, sa);
 433         ptr = nt_s390_tod_preg(ptr, sa);
 434         ptr = nt_s390_ctrs(ptr, sa);
 435         ptr = nt_s390_prefix(ptr, sa);
 436         if (MACHINE_HAS_VX && vx_regs) {
 437                 ptr = nt_s390_vx_low(ptr, vx_regs);
 438                 ptr = nt_s390_vx_high(ptr, vx_regs);
 439         }
 440         return ptr;
 441 }
 442
 443 /*
 444  * Initialize prpsinfo note (new kernel)
 445  */
 446 static void *nt_prpsinfo(void *ptr)
 447 {
 448         struct elf_prpsinfo prpsinfo;
 449
 450         memset(&prpsinfo, 0, sizeof(prpsinfo));
 451         prpsinfo.pr_sname = 'R';
 452         strcpy(prpsinfo.pr_fname, "vmlinux");
 453         return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo),
 454                        KEXEC_CORE_NOTE_NAME);
 455 }
 456
 457 /*
 458  * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
 459  */
 460 static void *get_vmcoreinfo_old(unsigned long *size)
 461 {
 462         char nt_name[11], *vmcoreinfo;
 463         Elf64_Nhdr note;
 464         void *addr;
 465
 466         if (copy_from_oldmem(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
 467                 return NULL;
 468         memset(nt_name, 0, sizeof(nt_name));
 469         if (copy_from_oldmem(&note, addr, sizeof(note)))
 470                 return NULL;
 471         if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1))
 472                 return NULL;
 473         if (strcmp(nt_name, "VMCOREINFO") != 0)
 474                 return NULL;
 475         vmcoreinfo = kzalloc_panic(note.n_descsz);
 476         if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz))
 477                 return NULL;
 478         *size = note.n_descsz;
 479         return vmcoreinfo;
 480 }
 481
 482 /*
 483  * Initialize vmcoreinfo note (new kernel)
 484  */
 485 static void *nt_vmcoreinfo(void *ptr)
 486 {
 487         unsigned long size;
 488         void *vmcoreinfo;
 489
 490         vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
 491         if (!vmcoreinfo)
 492                 vmcoreinfo = get_vmcoreinfo_old(&size);
 493         if (!vmcoreinfo)
 494                 return ptr;
 495         return nt_init(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
 496 }
 497
 498 /*
 499  * Initialize ELF header (new kernel)
 500  */
 501 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
 502 {
 503         memset(ehdr, 0, sizeof(*ehdr));
 504         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 505         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 506         ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
 507         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 508         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 509         ehdr->e_type = ET_CORE;
 510         ehdr->e_machine = EM_S390;
 511         ehdr->e_version = EV_CURRENT;
 512         ehdr->e_phoff = sizeof(Elf64_Ehdr);
 513         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
 514         ehdr->e_phentsize = sizeof(Elf64_Phdr);
 515         ehdr->e_phnum = mem_chunk_cnt + 1;
 516         return ehdr + 1;
 517 }
 518
 519 /*
 520  * Return CPU count for ELF header (new kernel)
 521  */
 522 static int get_cpu_cnt(void)
 523 {
 524         int i, cpus = 0;
 525
 526         for (i = 0; i < dump_save_areas.count; i++) {
 527                 if (dump_save_areas.areas[i]->sa.pref_reg == 0)
 528                         continue;
 529                 cpus++;
 530         }
 531         return cpus;
 532 }
 533
 534 /*
 535  * Return memory chunk count for ELF header (new kernel)
 536  */
 537 static int get_mem_chunk_cnt(void)
 538 {
 539         int cnt = 0;
 540         u64 idx;
 541
 542         for_each_dump_mem_range(idx, NUMA_NO_NODE, NULL, NULL, NULL)
 543                 cnt++;
 544         return cnt;
 545 }
 546
 547 /*
 548  * Initialize ELF loads (new kernel)
 549  */
 550 static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
 551 {
 552         phys_addr_t start, end;
 553         u64 idx;
 554
 555         for_each_dump_mem_range(idx, NUMA_NO_NODE, &start, &end, NULL) {
 556                 phdr->p_filesz = end - start;
 557                 phdr->p_type = PT_LOAD;
 558                 phdr->p_offset = start;
 559                 phdr->p_vaddr = start;
 560                 phdr->p_paddr = start;
 561                 phdr->p_memsz = end - start;
 562                 phdr->p_flags = PF_R | PF_W | PF_X;
 563                 phdr->p_align = PAGE_SIZE;
 564                 phdr++;
 565         }
 566 }
 567
 568 /*
 569  * Initialize notes (new kernel)
 570  */
 571 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
 572 {
 573         struct save_area_ext *sa_ext;
 574         void *ptr_start = ptr;
 575         int i;
 576
 577         ptr = nt_prpsinfo(ptr);
 578
 579         for (i = 0; i < dump_save_areas.count; i++) {
 580                 sa_ext = dump_save_areas.areas[i];
 581                 if (sa_ext->sa.pref_reg == 0)
 582                         continue;
 583                 ptr = fill_cpu_elf_notes(ptr, &sa_ext->sa, sa_ext->vx_regs);
 584         }
 585         ptr = nt_vmcoreinfo(ptr);
 586         memset(phdr, 0, sizeof(*phdr));
 587         phdr->p_type = PT_NOTE;
 588         phdr->p_offset = notes_offset;
 589         phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
 590         phdr->p_memsz = phdr->p_filesz;
 591         return ptr;
 592 }
 593
 594 /*
 595  * Create ELF core header (new kernel)
 596  */
 597 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
 598 {
 599         Elf64_Phdr *phdr_notes, *phdr_loads;
 600         int mem_chunk_cnt;
 601         void *ptr, *hdr;
 602         u32 alloc_size;
 603         u64 hdr_off;
 604
 605         /* If we are not in kdump or zfcpdump mode return */
 606         if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
 607                 return 0;
 608         /* If elfcorehdr= has been passed via cmdline, we use that one */
 609         if (elfcorehdr_addr != ELFCORE_ADDR_MAX)
 610                 return 0;
 611         /* If we cannot get HSA size for zfcpdump return error */
 612         if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp_get_hsa_size())
 613                 return -ENODEV;
 614
 615         /* For kdump, exclude previous crashkernel memory */
 616         if (OLDMEM_BASE) {
 617                 oldmem_region.base = OLDMEM_BASE;
 618                 oldmem_region.size = OLDMEM_SIZE;
 619                 oldmem_type.total_size = OLDMEM_SIZE;
 620         }
 621
 622         mem_chunk_cnt = get_mem_chunk_cnt();
 623
 624         alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 +
 625                 mem_chunk_cnt * sizeof(Elf64_Phdr);
 626         hdr = kzalloc_panic(alloc_size);
 627         /* Init elf header */
 628         ptr = ehdr_init(hdr, mem_chunk_cnt);
 629         /* Init program headers */
 630         phdr_notes = ptr;
 631         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
 632         phdr_loads = ptr;
 633         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
 634         /* Init notes */
 635         hdr_off = PTR_DIFF(ptr, hdr);
 636         ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
 637         /* Init loads */
 638         hdr_off = PTR_DIFF(ptr, hdr);
 639         loads_init(phdr_loads, hdr_off);
 640         *addr = (unsigned long long) hdr;
 641         elfcorehdr_newmem = hdr;
 642         *size = (unsigned long long) hdr_off;
 643         BUG_ON(elfcorehdr_size > alloc_size);
 644         return 0;
 645 }
 646
 647 /*
 648  * Free ELF core header (new kernel)
 649  */
 650 void elfcorehdr_free(unsigned long long addr)
 651 {
 652         if (!elfcorehdr_newmem)
 653                 return;
 654         kfree((void *)(unsigned long)addr);
 655 }
 656
 657 /*
 658  * Read from ELF header
 659  */
 660 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 661 {
 662         void *src = (void *)(unsigned long)*ppos;
 663
 664         src = elfcorehdr_newmem ? src : src - OLDMEM_BASE;
 665         memcpy(buf, src, count);
 666         *ppos += count;
 667         return count;
 668 }
 669
 670 /*
 671  * Read from ELF notes data
 672  */
 673 ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
 674 {
 675         void *src = (void *)(unsigned long)*ppos;
 676         int rc;
 677
 678         if (elfcorehdr_newmem) {
 679                 memcpy(buf, src, count);
 680         } else {
 681                 rc = copy_from_oldmem(buf, src, count);
 682                 if (rc)
 683                         return rc;
 684         }
 685         *ppos += count;
 686         return count;
 687 }