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/asm-offsets.h>
  17 #include <linux/memblock.h>
  18 #include <asm/os_info.h>
  19 #include <asm/elf.h>
  20 #include <asm/ipl.h>
  21 #include <asm/sclp.h>
  22
  23 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
  24 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
  25 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
  26
  27 static struct memblock_region oldmem_region;
  28
  29 static struct memblock_type oldmem_type = {
  30         .cnt = 1,
  31         .max = 1,
  32         .total_size = 0,
  33         .regions = &oldmem_region,
  34 };
  35
  36 struct save_area {
  37         struct list_head list;
  38         u64 psw[2];
  39         u64 ctrs[16];
  40         u64 gprs[16];
  41         u32 acrs[16];
  42         u64 fprs[16];
  43         u32 fpc;
  44         u32 prefix;
  45         u64 todpreg;
  46         u64 timer;
  47         u64 todcmp;
  48         u64 vxrs_low[16];
  49         __vector128 vxrs_high[16];
  50 };
  51
  52 static LIST_HEAD(dump_save_areas);
  53
  54 /*
  55  * Allocate a save area
  56  */
  57 struct save_area * __init save_area_alloc(bool is_boot_cpu)
  58 {
  59         struct save_area *sa;
  60
  61         sa = (void *) memblock_alloc(sizeof(*sa), 8);
  62         if (is_boot_cpu)
  63                 list_add(&sa->list, &dump_save_areas);
  64         else
  65                 list_add_tail(&sa->list, &dump_save_areas);
  66         return sa;
  67 }
  68
  69 /*
  70  * Return the address of the save area for the boot CPU
  71  */
  72 struct save_area * __init save_area_boot_cpu(void)
  73 {
  74         return list_first_entry_or_null(&dump_save_areas, struct save_area, list);
  75 }
  76
  77 /*
  78  * Copy CPU registers into the save area
  79  */
  80 void __init save_area_add_regs(struct save_area *sa, void *regs)
  81 {
  82         struct lowcore *lc;
  83
  84         lc = (struct lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
  85         memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
  86         memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
  87         memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
  88         memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
  89         memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
  90         memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
  91         memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
  92         memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
  93         memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
  94         memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
  95 }
  96
  97 /*
  98  * Copy vector registers into the save area
  99  */
 100 void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
 101 {
 102         int i;
 103
 104         /* Copy lower halves of vector registers 0-15 */
 105         for (i = 0; i < 16; i++)
 106                 memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
 107         /* Copy vector registers 16-31 */
 108         memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
 109 }
 110
 111 /*
 112  * Return physical address for virtual address
 113  */
 114 static inline void *load_real_addr(void *addr)
 115 {
 116         unsigned long real_addr;
 117
 118         asm volatile(
 119                    "    lra     %0,0(%1)\n"
 120                    "    jz      0f\n"
 121                    "    la      %0,0\n"
 122                    "0:"
 123                    : "=a" (real_addr) : "a" (addr) : "cc");
 124         return (void *)real_addr;
 125 }
 126
 127 /*
 128  * Copy memory of the old, dumped system to a kernel space virtual address
 129  */
 130 int copy_oldmem_kernel(void *dst, void *src, size_t count)
 131 {
 132         unsigned long from, len;
 133         void *ra;
 134         int rc;
 135
 136         while (count) {
 137                 from = __pa(src);
 138                 if (!OLDMEM_BASE && from < sclp.hsa_size) {
 139                         /* Copy from zfcpdump HSA area */
 140                         len = min(count, sclp.hsa_size - from);
 141                         rc = memcpy_hsa_kernel(dst, from, len);
 142                         if (rc)
 143                                 return rc;
 144                 } else {
 145                         /* Check for swapped kdump oldmem areas */
 146                         if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
 147                                 from -= OLDMEM_BASE;
 148                                 len = min(count, OLDMEM_SIZE - from);
 149                         } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
 150                                 len = min(count, OLDMEM_SIZE - from);
 151                                 from += OLDMEM_BASE;
 152                         } else {
 153                                 len = count;
 154                         }
 155                         if (is_vmalloc_or_module_addr(dst)) {
 156                                 ra = load_real_addr(dst);
 157                                 len = min(PAGE_SIZE - offset_in_page(ra), len);
 158                         } else {
 159                                 ra = dst;
 160                         }
 161                         if (memcpy_real(ra, (void *) from, len))
 162                                 return -EFAULT;
 163                 }
 164                 dst += len;
 165                 src += len;
 166                 count -= len;
 167         }
 168         return 0;
 169 }
 170
 171 /*
 172  * Copy memory of the old, dumped system to a user space virtual address
 173  */
 174 static int copy_oldmem_user(void __user *dst, void *src, size_t count)
 175 {
 176         unsigned long from, len;
 177         int rc;
 178
 179         while (count) {
 180                 from = __pa(src);
 181                 if (!OLDMEM_BASE && from < sclp.hsa_size) {
 182                         /* Copy from zfcpdump HSA area */
 183                         len = min(count, sclp.hsa_size - from);
 184                         rc = memcpy_hsa_user(dst, from, len);
 185                         if (rc)
 186                                 return rc;
 187                 } else {
 188                         /* Check for swapped kdump oldmem areas */
 189                         if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
 190                                 from -= OLDMEM_BASE;
 191                                 len = min(count, OLDMEM_SIZE - from);
 192                         } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
 193                                 len = min(count, OLDMEM_SIZE - from);
 194                                 from += OLDMEM_BASE;
 195                         } else {
 196                                 len = count;
 197                         }
 198                         rc = copy_to_user_real(dst, (void *) from, count);
 199                         if (rc)
 200                                 return rc;
 201                 }
 202                 dst += len;
 203                 src += len;
 204                 count -= len;
 205         }
 206         return 0;
 207 }
 208
 209 /*
 210  * Copy one page from "oldmem"
 211  */
 212 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
 213                          unsigned long offset, int userbuf)
 214 {
 215         void *src;
 216         int rc;
 217
 218         if (!csize)
 219                 return 0;
 220         src = (void *) (pfn << PAGE_SHIFT) + offset;
 221         if (userbuf)
 222                 rc = copy_oldmem_user((void __force __user *) buf, src, csize);
 223         else
 224                 rc = copy_oldmem_kernel((void *) buf, src, csize);
 225         return rc;
 226 }
 227
 228 /*
 229  * Remap "oldmem" for kdump
 230  *
 231  * For the kdump reserved memory this functions performs a swap operation:
 232  * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
 233  */
 234 static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
 235                                         unsigned long from, unsigned long pfn,
 236                                         unsigned long size, pgprot_t prot)
 237 {
 238         unsigned long size_old;
 239         int rc;
 240
 241         if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
 242                 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
 243                 rc = remap_pfn_range(vma, from,
 244                                      pfn + (OLDMEM_BASE >> PAGE_SHIFT),
 245                                      size_old, prot);
 246                 if (rc || size == size_old)
 247                         return rc;
 248                 size -= size_old;
 249                 from += size_old;
 250                 pfn += size_old >> PAGE_SHIFT;
 251         }
 252         return remap_pfn_range(vma, from, pfn, size, prot);
 253 }
 254
 255 /*
 256  * Remap "oldmem" for zfcpdump
 257  *
 258  * We only map available memory above HSA size. Memory below HSA size
 259  * is read on demand using the copy_oldmem_page() function.
 260  */
 261 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
 262                                            unsigned long from,
 263                                            unsigned long pfn,
 264                                            unsigned long size, pgprot_t prot)
 265 {
 266         unsigned long hsa_end = sclp.hsa_size;
 267         unsigned long size_hsa;
 268
 269         if (pfn < hsa_end >> PAGE_SHIFT) {
 270                 size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
 271                 if (size == size_hsa)
 272                         return 0;
 273                 size -= size_hsa;
 274                 from += size_hsa;
 275                 pfn += size_hsa >> PAGE_SHIFT;
 276         }
 277         return remap_pfn_range(vma, from, pfn, size, prot);
 278 }
 279
 280 /*
 281  * Remap "oldmem" for kdump or zfcpdump
 282  */
 283 int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
 284                            unsigned long pfn, unsigned long size, pgprot_t prot)
 285 {
 286         if (OLDMEM_BASE)
 287                 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
 288         else
 289                 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
 290                                                        prot);
 291 }
 292
 293 /*
 294  * Alloc memory and panic in case of ENOMEM
 295  */
 296 static void *kzalloc_panic(int len)
 297 {
 298         void *rc;
 299
 300         rc = kzalloc(len, GFP_KERNEL);
 301         if (!rc)
 302                 panic("s390 kdump kzalloc (%d) failed", len);
 303         return rc;
 304 }
 305
 306 /*
 307  * Initialize ELF note
 308  */
 309 static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
 310                           const char *name)
 311 {
 312         Elf64_Nhdr *note;
 313         u64 len;
 314
 315         note = (Elf64_Nhdr *)buf;
 316         note->n_namesz = strlen(name) + 1;
 317         note->n_descsz = d_len;
 318         note->n_type = type;
 319         len = sizeof(Elf64_Nhdr);
 320
 321         memcpy(buf + len, name, note->n_namesz);
 322         len = roundup(len + note->n_namesz, 4);
 323
 324         memcpy(buf + len, desc, note->n_descsz);
 325         len = roundup(len + note->n_descsz, 4);
 326
 327         return PTR_ADD(buf, len);
 328 }
 329
 330 static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
 331 {
 332         return nt_init_name(buf, type, desc, d_len, KEXEC_CORE_NOTE_NAME);
 333 }
 334
 335 /*
 336  * Fill ELF notes for one CPU with save area registers
 337  */
 338 static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
 339 {
 340         struct elf_prstatus nt_prstatus;
 341         elf_fpregset_t nt_fpregset;
 342
 343         /* Prepare prstatus note */
 344         memset(&nt_prstatus, 0, sizeof(nt_prstatus));
 345         memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
 346         memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
 347         memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
 348         nt_prstatus.pr_pid = cpu;
 349         /* Prepare fpregset (floating point) note */
 350         memset(&nt_fpregset, 0, sizeof(nt_fpregset));
 351         memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
 352         memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
 353         /* Create ELF notes for the CPU */
 354         ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
 355         ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
 356         ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
 357         ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
 358         ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
 359         ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
 360         ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
 361         if (MACHINE_HAS_VX) {
 362                 ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
 363                               &sa->vxrs_high, sizeof(sa->vxrs_high));
 364                 ptr = nt_init(ptr, NT_S390_VXRS_LOW,
 365                               &sa->vxrs_low, sizeof(sa->vxrs_low));
 366         }
 367         return ptr;
 368 }
 369
 370 /*
 371  * Initialize prpsinfo note (new kernel)
 372  */
 373 static void *nt_prpsinfo(void *ptr)
 374 {
 375         struct elf_prpsinfo prpsinfo;
 376
 377         memset(&prpsinfo, 0, sizeof(prpsinfo));
 378         prpsinfo.pr_sname = 'R';
 379         strcpy(prpsinfo.pr_fname, "vmlinux");
 380         return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
 381 }
 382
 383 /*
 384  * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
 385  */
 386 static void *get_vmcoreinfo_old(unsigned long *size)
 387 {
 388         char nt_name[11], *vmcoreinfo;
 389         Elf64_Nhdr note;
 390         void *addr;
 391
 392         if (copy_oldmem_kernel(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
 393                 return NULL;
 394         memset(nt_name, 0, sizeof(nt_name));
 395         if (copy_oldmem_kernel(&note, addr, sizeof(note)))
 396                 return NULL;
 397         if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
 398                                sizeof(nt_name) - 1))
 399                 return NULL;
 400         if (strcmp(nt_name, "VMCOREINFO") != 0)
 401                 return NULL;
 402         vmcoreinfo = kzalloc_panic(note.n_descsz);
 403         if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz))
 404                 return NULL;
 405         *size = note.n_descsz;
 406         return vmcoreinfo;
 407 }
 408
 409 /*
 410  * Initialize vmcoreinfo note (new kernel)
 411  */
 412 static void *nt_vmcoreinfo(void *ptr)
 413 {
 414         unsigned long size;
 415         void *vmcoreinfo;
 416
 417         vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
 418         if (!vmcoreinfo)
 419                 vmcoreinfo = get_vmcoreinfo_old(&size);
 420         if (!vmcoreinfo)
 421                 return ptr;
 422         return nt_init_name(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
 423 }
 424
 425 /*
 426  * Initialize ELF header (new kernel)
 427  */
 428 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
 429 {
 430         memset(ehdr, 0, sizeof(*ehdr));
 431         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 432         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 433         ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
 434         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 435         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 436         ehdr->e_type = ET_CORE;
 437         ehdr->e_machine = EM_S390;
 438         ehdr->e_version = EV_CURRENT;
 439         ehdr->e_phoff = sizeof(Elf64_Ehdr);
 440         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
 441         ehdr->e_phentsize = sizeof(Elf64_Phdr);
 442         ehdr->e_phnum = mem_chunk_cnt + 1;
 443         return ehdr + 1;
 444 }
 445
 446 /*
 447  * Return CPU count for ELF header (new kernel)
 448  */
 449 static int get_cpu_cnt(void)
 450 {
 451         struct save_area *sa;
 452         int cpus = 0;
 453
 454         list_for_each_entry(sa, &dump_save_areas, list)
 455                 if (sa->prefix != 0)
 456                         cpus++;
 457         return cpus;
 458 }
 459
 460 /*
 461  * Return memory chunk count for ELF header (new kernel)
 462  */
 463 static int get_mem_chunk_cnt(void)
 464 {
 465         int cnt = 0;
 466         u64 idx;
 467
 468         for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
 469                            MEMBLOCK_NONE, NULL, NULL, NULL)
 470                 cnt++;
 471         return cnt;
 472 }
 473
 474 /*
 475  * Initialize ELF loads (new kernel)
 476  */
 477 static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
 478 {
 479         phys_addr_t start, end;
 480         u64 idx;
 481
 482         for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
 483                            MEMBLOCK_NONE, &start, &end, NULL) {
 484                 phdr->p_filesz = end - start;
 485                 phdr->p_type = PT_LOAD;
 486                 phdr->p_offset = start;
 487                 phdr->p_vaddr = start;
 488                 phdr->p_paddr = start;
 489                 phdr->p_memsz = end - start;
 490                 phdr->p_flags = PF_R | PF_W | PF_X;
 491                 phdr->p_align = PAGE_SIZE;
 492                 phdr++;
 493         }
 494 }
 495
 496 /*
 497  * Initialize notes (new kernel)
 498  */
 499 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
 500 {
 501         struct save_area *sa;
 502         void *ptr_start = ptr;
 503         int cpu;
 504
 505         ptr = nt_prpsinfo(ptr);
 506
 507         cpu = 1;
 508         list_for_each_entry(sa, &dump_save_areas, list)
 509                 if (sa->prefix != 0)
 510                         ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
 511         ptr = nt_vmcoreinfo(ptr);
 512         memset(phdr, 0, sizeof(*phdr));
 513         phdr->p_type = PT_NOTE;
 514         phdr->p_offset = notes_offset;
 515         phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
 516         phdr->p_memsz = phdr->p_filesz;
 517         return ptr;
 518 }
 519
 520 /*
 521  * Create ELF core header (new kernel)
 522  */
 523 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
 524 {
 525         Elf64_Phdr *phdr_notes, *phdr_loads;
 526         int mem_chunk_cnt;
 527         void *ptr, *hdr;
 528         u32 alloc_size;
 529         u64 hdr_off;
 530
 531         /* If we are not in kdump or zfcpdump mode return */
 532         if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
 533                 return 0;
 534         /* If we cannot get HSA size for zfcpdump return error */
 535         if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size)
 536                 return -ENODEV;
 537
 538         /* For kdump, exclude previous crashkernel memory */
 539         if (OLDMEM_BASE) {
 540                 oldmem_region.base = OLDMEM_BASE;
 541                 oldmem_region.size = OLDMEM_SIZE;
 542                 oldmem_type.total_size = OLDMEM_SIZE;
 543         }
 544
 545         mem_chunk_cnt = get_mem_chunk_cnt();
 546
 547         alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 +
 548                 mem_chunk_cnt * sizeof(Elf64_Phdr);
 549         hdr = kzalloc_panic(alloc_size);
 550         /* Init elf header */
 551         ptr = ehdr_init(hdr, mem_chunk_cnt);
 552         /* Init program headers */
 553         phdr_notes = ptr;
 554         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
 555         phdr_loads = ptr;
 556         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
 557         /* Init notes */
 558         hdr_off = PTR_DIFF(ptr, hdr);
 559         ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
 560         /* Init loads */
 561         hdr_off = PTR_DIFF(ptr, hdr);
 562         loads_init(phdr_loads, hdr_off);
 563         *addr = (unsigned long long) hdr;
 564         *size = (unsigned long long) hdr_off;
 565         BUG_ON(elfcorehdr_size > alloc_size);
 566         return 0;
 567 }
 568
 569 /*
 570  * Free ELF core header (new kernel)
 571  */
 572 void elfcorehdr_free(unsigned long long addr)
 573 {
 574         kfree((void *)(unsigned long)addr);
 575 }
 576
 577 /*
 578  * Read from ELF header
 579  */
 580 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 581 {
 582         void *src = (void *)(unsigned long)*ppos;
 583
 584         memcpy(buf, src, count);
 585         *ppos += count;
 586         return count;
 587 }
 588
 589 /*
 590  * Read from ELF notes data
 591  */
 592 ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
 593 {
 594         void *src = (void *)(unsigned long)*ppos;
 595
 596         memcpy(buf, src, count);
 597         *ppos += count;
 598         return count;
 599 }