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 <asm/os_info.h>
  17 #include <asm/elf.h>
  18 #include <asm/ipl.h>
  19 #include <asm/sclp.h>
  20
  21 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
  22 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
  23 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
  24
  25
  26 /*
  27  * Return physical address for virtual address
  28  */
  29 static inline void *load_real_addr(void *addr)
  30 {
  31         unsigned long real_addr;
  32
  33         asm volatile(
  34                    "    lra     %0,0(%1)\n"
  35                    "    jz      0f\n"
  36                    "    la      %0,0\n"
  37                    "0:"
  38                    : "=a" (real_addr) : "a" (addr) : "cc");
  39         return (void *)real_addr;
  40 }
  41
  42 /*
  43  * Copy real to virtual or real memory
  44  */
  45 static int copy_from_realmem(void *dest, void *src, size_t count)
  46 {
  47         unsigned long size;
  48         int rc;
  49
  50         if (!count)
  51                 return 0;
  52         if (!is_vmalloc_or_module_addr(dest))
  53                 return memcpy_real(dest, src, count);
  54         do {
  55                 size = min(count, PAGE_SIZE - (__pa(dest) & ~PAGE_MASK));
  56                 if (memcpy_real(load_real_addr(dest), src, size))
  57                         return -EFAULT;
  58                 count -= size;
  59                 dest += size;
  60                 src += size;
  61         } while (count);
  62         return 0;
  63 }
  64
  65 /*
  66  * Pointer to ELF header in new kernel
  67  */
  68 static void *elfcorehdr_newmem;
  69
  70 /*
  71  * Copy one page from zfcpdump "oldmem"
  72  *
  73  * For pages below ZFCPDUMP_HSA_SIZE memory from the HSA is copied. Otherwise
  74  * real memory copy is used.
  75  */
  76 static ssize_t copy_oldmem_page_zfcpdump(char *buf, size_t csize,
  77                                          unsigned long src, int userbuf)
  78 {
  79         int rc;
  80
  81         if (src < ZFCPDUMP_HSA_SIZE) {
  82                 rc = memcpy_hsa(buf, src, csize, userbuf);
  83         } else {
  84                 if (userbuf)
  85                         rc = copy_to_user_real((void __force __user *) buf,
  86                                                (void *) src, csize);
  87                 else
  88                         rc = memcpy_real(buf, (void *) src, csize);
  89         }
  90         return rc ? rc : csize;
  91 }
  92
  93 /*
  94  * Copy one page from kdump "oldmem"
  95  *
  96  * For the kdump reserved memory this functions performs a swap operation:
  97  *  - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE].
  98  *  - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
  99  */
 100 static ssize_t copy_oldmem_page_kdump(char *buf, size_t csize,
 101                                       unsigned long src, int userbuf)
 102
 103 {
 104         int rc;
 105
 106         if (src < OLDMEM_SIZE)
 107                 src += OLDMEM_BASE;
 108         else if (src > OLDMEM_BASE &&
 109                  src < OLDMEM_BASE + OLDMEM_SIZE)
 110                 src -= OLDMEM_BASE;
 111         if (userbuf)
 112                 rc = copy_to_user_real((void __force __user *) buf,
 113                                        (void *) src, csize);
 114         else
 115                 rc = copy_from_realmem(buf, (void *) src, csize);
 116         return (rc == 0) ? rc : csize;
 117 }
 118
 119 /*
 120  * Copy one page from "oldmem"
 121  */
 122 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
 123                          unsigned long offset, int userbuf)
 124 {
 125         unsigned long src;
 126
 127         if (!csize)
 128                 return 0;
 129         src = (pfn << PAGE_SHIFT) + offset;
 130         if (OLDMEM_BASE)
 131                 return copy_oldmem_page_kdump(buf, csize, src, userbuf);
 132         else
 133                 return copy_oldmem_page_zfcpdump(buf, csize, src, userbuf);
 134 }
 135
 136 /*
 137  * Remap "oldmem" for kdump
 138  *
 139  * For the kdump reserved memory this functions performs a swap operation:
 140  * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
 141  */
 142 static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
 143                                         unsigned long from, unsigned long pfn,
 144                                         unsigned long size, pgprot_t prot)
 145 {
 146         unsigned long size_old;
 147         int rc;
 148
 149         if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
 150                 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
 151                 rc = remap_pfn_range(vma, from,
 152                                      pfn + (OLDMEM_BASE >> PAGE_SHIFT),
 153                                      size_old, prot);
 154                 if (rc || size == size_old)
 155                         return rc;
 156                 size -= size_old;
 157                 from += size_old;
 158                 pfn += size_old >> PAGE_SHIFT;
 159         }
 160         return remap_pfn_range(vma, from, pfn, size, prot);
 161 }
 162
 163 /*
 164  * Remap "oldmem" for zfcpdump
 165  *
 166  * We only map available memory above ZFCPDUMP_HSA_SIZE. Memory below
 167  * ZFCPDUMP_HSA_SIZE is read on demand using the copy_oldmem_page() function.
 168  */
 169 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
 170                                            unsigned long from,
 171                                            unsigned long pfn,
 172                                            unsigned long size, pgprot_t prot)
 173 {
 174         unsigned long size_hsa;
 175
 176         if (pfn < ZFCPDUMP_HSA_SIZE >> PAGE_SHIFT) {
 177                 size_hsa = min(size, ZFCPDUMP_HSA_SIZE - (pfn << PAGE_SHIFT));
 178                 if (size == size_hsa)
 179                         return 0;
 180                 size -= size_hsa;
 181                 from += size_hsa;
 182                 pfn += size_hsa >> PAGE_SHIFT;
 183         }
 184         return remap_pfn_range(vma, from, pfn, size, prot);
 185 }
 186
 187 /*
 188  * Remap "oldmem" for kdump or zfcpdump
 189  */
 190 int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
 191                            unsigned long pfn, unsigned long size, pgprot_t prot)
 192 {
 193         if (OLDMEM_BASE)
 194                 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
 195         else
 196                 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
 197                                                        prot);
 198 }
 199
 200 /*
 201  * Copy memory from old kernel
 202  */
 203 int copy_from_oldmem(void *dest, void *src, size_t count)
 204 {
 205         unsigned long copied = 0;
 206         int rc;
 207
 208         if (OLDMEM_BASE) {
 209                 if ((unsigned long) src < OLDMEM_SIZE) {
 210                         copied = min(count, OLDMEM_SIZE - (unsigned long) src);
 211                         rc = copy_from_realmem(dest, src + OLDMEM_BASE, copied);
 212                         if (rc)
 213                                 return rc;
 214                 }
 215         } else {
 216                 if ((unsigned long) src < ZFCPDUMP_HSA_SIZE) {
 217                         copied = min(count,
 218                                      ZFCPDUMP_HSA_SIZE - (unsigned long) src);
 219                         rc = memcpy_hsa(dest, (unsigned long) src, copied, 0);
 220                         if (rc)
 221                                 return rc;
 222                 }
 223         }
 224         return copy_from_realmem(dest + copied, src + copied, count - copied);
 225 }
 226
 227 /*
 228  * Alloc memory and panic in case of ENOMEM
 229  */
 230 static void *kzalloc_panic(int len)
 231 {
 232         void *rc;
 233
 234         rc = kzalloc(len, GFP_KERNEL);
 235         if (!rc)
 236                 panic("s390 kdump kzalloc (%d) failed", len);
 237         return rc;
 238 }
 239
 240 /*
 241  * Get memory layout and create hole for oldmem
 242  */
 243 static struct mem_chunk *get_memory_layout(void)
 244 {
 245         struct mem_chunk *chunk_array;
 246
 247         chunk_array = kzalloc_panic(MEMORY_CHUNKS * sizeof(struct mem_chunk));
 248         detect_memory_layout(chunk_array, 0);
 249         create_mem_hole(chunk_array, OLDMEM_BASE, OLDMEM_SIZE);
 250         return chunk_array;
 251 }
 252
 253 /*
 254  * Initialize ELF note
 255  */
 256 static void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len,
 257                      const char *name)
 258 {
 259         Elf64_Nhdr *note;
 260         u64 len;
 261
 262         note = (Elf64_Nhdr *)buf;
 263         note->n_namesz = strlen(name) + 1;
 264         note->n_descsz = d_len;
 265         note->n_type = type;
 266         len = sizeof(Elf64_Nhdr);
 267
 268         memcpy(buf + len, name, note->n_namesz);
 269         len = roundup(len + note->n_namesz, 4);
 270
 271         memcpy(buf + len, desc, note->n_descsz);
 272         len = roundup(len + note->n_descsz, 4);
 273
 274         return PTR_ADD(buf, len);
 275 }
 276
 277 /*
 278  * Initialize prstatus note
 279  */
 280 static void *nt_prstatus(void *ptr, struct save_area *sa)
 281 {
 282         struct elf_prstatus nt_prstatus;
 283         static int cpu_nr = 1;
 284
 285         memset(&nt_prstatus, 0, sizeof(nt_prstatus));
 286         memcpy(&nt_prstatus.pr_reg.gprs, sa->gp_regs, sizeof(sa->gp_regs));
 287         memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
 288         memcpy(&nt_prstatus.pr_reg.acrs, sa->acc_regs, sizeof(sa->acc_regs));
 289         nt_prstatus.pr_pid = cpu_nr;
 290         cpu_nr++;
 291
 292         return nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus),
 293                          "CORE");
 294 }
 295
 296 /*
 297  * Initialize fpregset (floating point) note
 298  */
 299 static void *nt_fpregset(void *ptr, struct save_area *sa)
 300 {
 301         elf_fpregset_t nt_fpregset;
 302
 303         memset(&nt_fpregset, 0, sizeof(nt_fpregset));
 304         memcpy(&nt_fpregset.fpc, &sa->fp_ctrl_reg, sizeof(sa->fp_ctrl_reg));
 305         memcpy(&nt_fpregset.fprs, &sa->fp_regs, sizeof(sa->fp_regs));
 306
 307         return nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset),
 308                        "CORE");
 309 }
 310
 311 /*
 312  * Initialize timer note
 313  */
 314 static void *nt_s390_timer(void *ptr, struct save_area *sa)
 315 {
 316         return nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer),
 317                          KEXEC_CORE_NOTE_NAME);
 318 }
 319
 320 /*
 321  * Initialize TOD clock comparator note
 322  */
 323 static void *nt_s390_tod_cmp(void *ptr, struct save_area *sa)
 324 {
 325         return nt_init(ptr, NT_S390_TODCMP, &sa->clk_cmp,
 326                        sizeof(sa->clk_cmp), KEXEC_CORE_NOTE_NAME);
 327 }
 328
 329 /*
 330  * Initialize TOD programmable register note
 331  */
 332 static void *nt_s390_tod_preg(void *ptr, struct save_area *sa)
 333 {
 334         return nt_init(ptr, NT_S390_TODPREG, &sa->tod_reg,
 335                        sizeof(sa->tod_reg), KEXEC_CORE_NOTE_NAME);
 336 }
 337
 338 /*
 339  * Initialize control register note
 340  */
 341 static void *nt_s390_ctrs(void *ptr, struct save_area *sa)
 342 {
 343         return nt_init(ptr, NT_S390_CTRS, &sa->ctrl_regs,
 344                        sizeof(sa->ctrl_regs), KEXEC_CORE_NOTE_NAME);
 345 }
 346
 347 /*
 348  * Initialize prefix register note
 349  */
 350 static void *nt_s390_prefix(void *ptr, struct save_area *sa)
 351 {
 352         return nt_init(ptr, NT_S390_PREFIX, &sa->pref_reg,
 353                          sizeof(sa->pref_reg), KEXEC_CORE_NOTE_NAME);
 354 }
 355
 356 /*
 357  * Fill ELF notes for one CPU with save area registers
 358  */
 359 void *fill_cpu_elf_notes(void *ptr, struct save_area *sa)
 360 {
 361         ptr = nt_prstatus(ptr, sa);
 362         ptr = nt_fpregset(ptr, sa);
 363         ptr = nt_s390_timer(ptr, sa);
 364         ptr = nt_s390_tod_cmp(ptr, sa);
 365         ptr = nt_s390_tod_preg(ptr, sa);
 366         ptr = nt_s390_ctrs(ptr, sa);
 367         ptr = nt_s390_prefix(ptr, sa);
 368         return ptr;
 369 }
 370
 371 /*
 372  * Initialize prpsinfo note (new kernel)
 373  */
 374 static void *nt_prpsinfo(void *ptr)
 375 {
 376         struct elf_prpsinfo prpsinfo;
 377
 378         memset(&prpsinfo, 0, sizeof(prpsinfo));
 379         prpsinfo.pr_sname = 'R';
 380         strcpy(prpsinfo.pr_fname, "vmlinux");
 381         return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo),
 382                        KEXEC_CORE_NOTE_NAME);
 383 }
 384
 385 /*
 386  * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
 387  */
 388 static void *get_vmcoreinfo_old(unsigned long *size)
 389 {
 390         char nt_name[11], *vmcoreinfo;
 391         Elf64_Nhdr note;
 392         void *addr;
 393
 394         if (copy_from_oldmem(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
 395                 return NULL;
 396         memset(nt_name, 0, sizeof(nt_name));
 397         if (copy_from_oldmem(&note, addr, sizeof(note)))
 398                 return NULL;
 399         if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1))
 400                 return NULL;
 401         if (strcmp(nt_name, "VMCOREINFO") != 0)
 402                 return NULL;
 403         vmcoreinfo = kzalloc_panic(note.n_descsz);
 404         if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz))
 405                 return NULL;
 406         *size = note.n_descsz;
 407         return vmcoreinfo;
 408 }
 409
 410 /*
 411  * Initialize vmcoreinfo note (new kernel)
 412  */
 413 static void *nt_vmcoreinfo(void *ptr)
 414 {
 415         unsigned long size;
 416         void *vmcoreinfo;
 417
 418         vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
 419         if (!vmcoreinfo)
 420                 vmcoreinfo = get_vmcoreinfo_old(&size);
 421         if (!vmcoreinfo)
 422                 return ptr;
 423         return nt_init(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
 424 }
 425
 426 /*
 427  * Initialize ELF header (new kernel)
 428  */
 429 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
 430 {
 431         memset(ehdr, 0, sizeof(*ehdr));
 432         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 433         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 434         ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
 435         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 436         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 437         ehdr->e_type = ET_CORE;
 438         ehdr->e_machine = EM_S390;
 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         ehdr->e_phnum = mem_chunk_cnt + 1;
 444         return ehdr + 1;
 445 }
 446
 447 /*
 448  * Return CPU count for ELF header (new kernel)
 449  */
 450 static int get_cpu_cnt(void)
 451 {
 452         int i, cpus = 0;
 453
 454         for (i = 0; zfcpdump_save_areas[i]; i++) {
 455                 if (zfcpdump_save_areas[i]->pref_reg == 0)
 456                         continue;
 457                 cpus++;
 458         }
 459         return cpus;
 460 }
 461
 462 /*
 463  * Return memory chunk count for ELF header (new kernel)
 464  */
 465 static int get_mem_chunk_cnt(void)
 466 {
 467         struct mem_chunk *chunk_array, *mem_chunk;
 468         int i, cnt = 0;
 469
 470         chunk_array = get_memory_layout();
 471         for (i = 0; i < MEMORY_CHUNKS; i++) {
 472                 mem_chunk = &chunk_array[i];
 473                 if (chunk_array[i].type != CHUNK_READ_WRITE &&
 474                     chunk_array[i].type != CHUNK_READ_ONLY)
 475                         continue;
 476                 if (mem_chunk->size == 0)
 477                         continue;
 478                 cnt++;
 479         }
 480         kfree(chunk_array);
 481         return cnt;
 482 }
 483
 484 /*
 485  * Initialize ELF loads (new kernel)
 486  */
 487 static int loads_init(Elf64_Phdr *phdr, u64 loads_offset)
 488 {
 489         struct mem_chunk *chunk_array, *mem_chunk;
 490         int i;
 491
 492         chunk_array = get_memory_layout();
 493         for (i = 0; i < MEMORY_CHUNKS; i++) {
 494                 mem_chunk = &chunk_array[i];
 495                 if (mem_chunk->size == 0)
 496                         continue;
 497                 if (chunk_array[i].type != CHUNK_READ_WRITE &&
 498                     chunk_array[i].type != CHUNK_READ_ONLY)
 499                         continue;
 500                 else
 501                         phdr->p_filesz = mem_chunk->size;
 502                 phdr->p_type = PT_LOAD;
 503                 phdr->p_offset = mem_chunk->addr;
 504                 phdr->p_vaddr = mem_chunk->addr;
 505                 phdr->p_paddr = mem_chunk->addr;
 506                 phdr->p_memsz = mem_chunk->size;
 507                 phdr->p_flags = PF_R | PF_W | PF_X;
 508                 phdr->p_align = PAGE_SIZE;
 509                 phdr++;
 510         }
 511         kfree(chunk_array);
 512         return i;
 513 }
 514
 515 /*
 516  * Initialize notes (new kernel)
 517  */
 518 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
 519 {
 520         struct save_area *sa;
 521         void *ptr_start = ptr;
 522         int i;
 523
 524         ptr = nt_prpsinfo(ptr);
 525
 526         for (i = 0; zfcpdump_save_areas[i]; i++) {
 527                 sa = zfcpdump_save_areas[i];
 528                 if (sa->pref_reg == 0)
 529                         continue;
 530                 ptr = fill_cpu_elf_notes(ptr, sa);
 531         }
 532         ptr = nt_vmcoreinfo(ptr);
 533         memset(phdr, 0, sizeof(*phdr));
 534         phdr->p_type = PT_NOTE;
 535         phdr->p_offset = notes_offset;
 536         phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
 537         phdr->p_memsz = phdr->p_filesz;
 538         return ptr;
 539 }
 540
 541 /*
 542  * Create ELF core header (new kernel)
 543  */
 544 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
 545 {
 546         Elf64_Phdr *phdr_notes, *phdr_loads;
 547         int mem_chunk_cnt;
 548         void *ptr, *hdr;
 549         u32 alloc_size;
 550         u64 hdr_off;
 551
 552         /* If we are not in kdump or zfcpdump mode return */
 553         if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
 554                 return 0;
 555         /* If elfcorehdr= has been passed via cmdline, we use that one */
 556         if (elfcorehdr_addr != ELFCORE_ADDR_MAX)
 557                 return 0;
 558         mem_chunk_cnt = get_mem_chunk_cnt();
 559
 560         alloc_size = 0x1000 + get_cpu_cnt() * 0x300 +
 561                 mem_chunk_cnt * sizeof(Elf64_Phdr);
 562         hdr = kzalloc_panic(alloc_size);
 563         /* Init elf header */
 564         ptr = ehdr_init(hdr, mem_chunk_cnt);
 565         /* Init program headers */
 566         phdr_notes = ptr;
 567         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
 568         phdr_loads = ptr;
 569         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
 570         /* Init notes */
 571         hdr_off = PTR_DIFF(ptr, hdr);
 572         ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
 573         /* Init loads */
 574         hdr_off = PTR_DIFF(ptr, hdr);
 575         loads_init(phdr_loads, hdr_off);
 576         *addr = (unsigned long long) hdr;
 577         elfcorehdr_newmem = hdr;
 578         *size = (unsigned long long) hdr_off;
 579         BUG_ON(elfcorehdr_size > alloc_size);
 580         return 0;
 581 }
 582
 583 /*
 584  * Free ELF core header (new kernel)
 585  */
 586 void elfcorehdr_free(unsigned long long addr)
 587 {
 588         if (!elfcorehdr_newmem)
 589                 return;
 590         kfree((void *)(unsigned long)addr);
 591 }
 592
 593 /*
 594  * Read from ELF header
 595  */
 596 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 597 {
 598         void *src = (void *)(unsigned long)*ppos;
 599
 600         src = elfcorehdr_newmem ? src : src - OLDMEM_BASE;
 601         memcpy(buf, src, count);
 602         *ppos += count;
 603         return count;
 604 }
 605
 606 /*
 607  * Read from ELF notes data
 608  */
 609 ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
 610 {
 611         void *src = (void *)(unsigned long)*ppos;
 612         int rc;
 613
 614         if (elfcorehdr_newmem) {
 615                 memcpy(buf, src, count);
 616         } else {
 617                 rc = copy_from_oldmem(buf, src, count);
 618                 if (rc)
 619                         return rc;
 620         }
 621         *ppos += count;
 622         return count;
 623 }