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/init.h>
  12 #include <linux/mm.h>
  13 #include <linux/gfp.h>
  14 #include <linux/slab.h>
  15 #include <linux/bootmem.h>
  16 #include <linux/elf.h>
  17 #include <asm/asm-offsets.h>
  18 #include <linux/memblock.h>
  19 #include <asm/os_info.h>
  20 #include <asm/elf.h>
  21 #include <asm/ipl.h>
  22 #include <asm/sclp.h>
  23
  24 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
  25 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
  26 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
  27
  28 static struct memblock_region oldmem_region;
  29
  30 static struct memblock_type oldmem_type = {
  31         .cnt = 1,
  32         .max = 1,
  33         .total_size = 0,
  34         .regions = &oldmem_region,
  35 };
  36
  37 struct save_area {
  38         struct list_head list;
  39         u64 psw[2];
  40         u64 ctrs[16];
  41         u64 gprs[16];
  42         u32 acrs[16];
  43         u64 fprs[16];
  44         u32 fpc;
  45         u32 prefix;
  46         u64 todpreg;
  47         u64 timer;
  48         u64 todcmp;
  49         u64 vxrs_low[16];
  50         __vector128 vxrs_high[16];
  51 };
  52
  53 static LIST_HEAD(dump_save_areas);
  54
  55 /*
  56  * Allocate a save area
  57  */
  58 struct save_area * __init save_area_alloc(bool is_boot_cpu)
  59 {
  60         struct save_area *sa;
  61
  62         sa = (void *) memblock_alloc(sizeof(*sa), 8);
  63         if (is_boot_cpu)
  64                 list_add(&sa->list, &dump_save_areas);
  65         else
  66                 list_add_tail(&sa->list, &dump_save_areas);
  67         return sa;
  68 }
  69
  70 /*
  71  * Return the address of the save area for the boot CPU
  72  */
  73 struct save_area * __init save_area_boot_cpu(void)
  74 {
  75         return list_first_entry_or_null(&dump_save_areas, struct save_area, list);
  76 }
  77
  78 /*
  79  * Copy CPU registers into the save area
  80  */
  81 void __init save_area_add_regs(struct save_area *sa, void *regs)
  82 {
  83         struct lowcore *lc;
  84
  85         lc = (struct lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
  86         memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
  87         memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
  88         memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
  89         memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
  90         memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
  91         memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
  92         memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
  93         memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
  94         memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
  95         memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
  96 }
  97
  98 /*
  99  * Copy vector registers into the save area
 100  */
 101 void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
 102 {
 103         int i;
 104
 105         /* Copy lower halves of vector registers 0-15 */
 106         for (i = 0; i < 16; i++)
 107                 memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
 108         /* Copy vector registers 16-31 */
 109         memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
 110 }
 111
 112 /*
 113  * Return physical address for virtual address
 114  */
 115 static inline void *load_real_addr(void *addr)
 116 {
 117         unsigned long real_addr;
 118
 119         asm volatile(
 120                    "    lra     %0,0(%1)\n"
 121                    "    jz      0f\n"
 122                    "    la      %0,0\n"
 123                    "0:"
 124                    : "=a" (real_addr) : "a" (addr) : "cc");
 125         return (void *)real_addr;
 126 }
 127
 128 /*
 129  * Copy memory of the old, dumped system to a kernel space virtual address
 130  */
 131 int copy_oldmem_kernel(void *dst, void *src, size_t count)
 132 {
 133         unsigned long from, len;
 134         void *ra;
 135         int rc;
 136
 137         while (count) {
 138                 from = __pa(src);
 139                 if (!OLDMEM_BASE && from < sclp.hsa_size) {
 140                         /* Copy from zfcpdump HSA area */
 141                         len = min(count, sclp.hsa_size - from);
 142                         rc = memcpy_hsa_kernel(dst, from, len);
 143                         if (rc)
 144                                 return rc;
 145                 } else {
 146                         /* Check for swapped kdump oldmem areas */
 147                         if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
 148                                 from -= OLDMEM_BASE;
 149                                 len = min(count, OLDMEM_SIZE - from);
 150                         } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
 151                                 len = min(count, OLDMEM_SIZE - from);
 152                                 from += OLDMEM_BASE;
 153                         } else {
 154                                 len = count;
 155                         }
 156                         if (is_vmalloc_or_module_addr(dst)) {
 157                                 ra = load_real_addr(dst);
 158                                 len = min(PAGE_SIZE - offset_in_page(ra), len);
 159                         } else {
 160                                 ra = dst;
 161                         }
 162                         if (memcpy_real(ra, (void *) from, len))
 163                                 return -EFAULT;
 164                 }
 165                 dst += len;
 166                 src += len;
 167                 count -= len;
 168         }
 169         return 0;
 170 }
 171
 172 /*
 173  * Copy memory of the old, dumped system to a user space virtual address
 174  */
 175 static int copy_oldmem_user(void __user *dst, void *src, size_t count)
 176 {
 177         unsigned long from, len;
 178         int rc;
 179
 180         while (count) {
 181                 from = __pa(src);
 182                 if (!OLDMEM_BASE && from < sclp.hsa_size) {
 183                         /* Copy from zfcpdump HSA area */
 184                         len = min(count, sclp.hsa_size - from);
 185                         rc = memcpy_hsa_user(dst, from, len);
 186                         if (rc)
 187                                 return rc;
 188                 } else {
 189                         /* Check for swapped kdump oldmem areas */
 190                         if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
 191                                 from -= OLDMEM_BASE;
 192                                 len = min(count, OLDMEM_SIZE - from);
 193                         } else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
 194                                 len = min(count, OLDMEM_SIZE - from);
 195                                 from += OLDMEM_BASE;
 196                         } else {
 197                                 len = count;
 198                         }
 199                         rc = copy_to_user_real(dst, (void *) from, count);
 200                         if (rc)
 201                                 return rc;
 202                 }
 203                 dst += len;
 204                 src += len;
 205                 count -= len;
 206         }
 207         return 0;
 208 }
 209
 210 /*
 211  * Copy one page from "oldmem"
 212  */
 213 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
 214                          unsigned long offset, int userbuf)
 215 {
 216         void *src;
 217         int rc;
 218
 219         if (!csize)
 220                 return 0;
 221         src = (void *) (pfn << PAGE_SHIFT) + offset;
 222         if (userbuf)
 223                 rc = copy_oldmem_user((void __force __user *) buf, src, csize);
 224         else
 225                 rc = copy_oldmem_kernel((void *) buf, src, csize);
 226         return rc;
 227 }
 228
 229 /*
 230  * Remap "oldmem" for kdump
 231  *
 232  * For the kdump reserved memory this functions performs a swap operation:
 233  * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
 234  */
 235 static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
 236                                         unsigned long from, unsigned long pfn,
 237                                         unsigned long size, pgprot_t prot)
 238 {
 239         unsigned long size_old;
 240         int rc;
 241
 242         if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
 243                 size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
 244                 rc = remap_pfn_range(vma, from,
 245                                      pfn + (OLDMEM_BASE >> PAGE_SHIFT),
 246                                      size_old, prot);
 247                 if (rc || size == size_old)
 248                         return rc;
 249                 size -= size_old;
 250                 from += size_old;
 251                 pfn += size_old >> PAGE_SHIFT;
 252         }
 253         return remap_pfn_range(vma, from, pfn, size, prot);
 254 }
 255
 256 /*
 257  * Remap "oldmem" for zfcpdump
 258  *
 259  * We only map available memory above HSA size. Memory below HSA size
 260  * is read on demand using the copy_oldmem_page() function.
 261  */
 262 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
 263                                            unsigned long from,
 264                                            unsigned long pfn,
 265                                            unsigned long size, pgprot_t prot)
 266 {
 267         unsigned long hsa_end = sclp.hsa_size;
 268         unsigned long size_hsa;
 269
 270         if (pfn < hsa_end >> PAGE_SHIFT) {
 271                 size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
 272                 if (size == size_hsa)
 273                         return 0;
 274                 size -= size_hsa;
 275                 from += size_hsa;
 276                 pfn += size_hsa >> PAGE_SHIFT;
 277         }
 278         return remap_pfn_range(vma, from, pfn, size, prot);
 279 }
 280
 281 /*
 282  * Remap "oldmem" for kdump or zfcpdump
 283  */
 284 int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
 285                            unsigned long pfn, unsigned long size, pgprot_t prot)
 286 {
 287         if (OLDMEM_BASE)
 288                 return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
 289         else
 290                 return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
 291                                                        prot);
 292 }
 293
 294 /*
 295  * Alloc memory and panic in case of ENOMEM
 296  */
 297 static void *kzalloc_panic(int len)
 298 {
 299         void *rc;
 300
 301         rc = kzalloc(len, GFP_KERNEL);
 302         if (!rc)
 303                 panic("s390 kdump kzalloc (%d) failed", len);
 304         return rc;
 305 }
 306
 307 /*
 308  * Initialize ELF note
 309  */
 310 static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
 311                           const char *name)
 312 {
 313         Elf64_Nhdr *note;
 314         u64 len;
 315
 316         note = (Elf64_Nhdr *)buf;
 317         note->n_namesz = strlen(name) + 1;
 318         note->n_descsz = d_len;
 319         note->n_type = type;
 320         len = sizeof(Elf64_Nhdr);
 321
 322         memcpy(buf + len, name, note->n_namesz);
 323         len = roundup(len + note->n_namesz, 4);
 324
 325         memcpy(buf + len, desc, note->n_descsz);
 326         len = roundup(len + note->n_descsz, 4);
 327
 328         return PTR_ADD(buf, len);
 329 }
 330
 331 static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
 332 {
 333         const char *note_name = "LINUX";
 334
 335         if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
 336                 note_name = KEXEC_CORE_NOTE_NAME;
 337         return nt_init_name(buf, type, desc, d_len, note_name);
 338 }
 339
 340 /*
 341  * Fill ELF notes for one CPU with save area registers
 342  */
 343 static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
 344 {
 345         struct elf_prstatus nt_prstatus;
 346         elf_fpregset_t nt_fpregset;
 347
 348         /* Prepare prstatus note */
 349         memset(&nt_prstatus, 0, sizeof(nt_prstatus));
 350         memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
 351         memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
 352         memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
 353         nt_prstatus.pr_pid = cpu;
 354         /* Prepare fpregset (floating point) note */
 355         memset(&nt_fpregset, 0, sizeof(nt_fpregset));
 356         memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
 357         memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
 358         /* Create ELF notes for the CPU */
 359         ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
 360         ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
 361         ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
 362         ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
 363         ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
 364         ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
 365         ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
 366         if (MACHINE_HAS_VX) {
 367                 ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
 368                               &sa->vxrs_high, sizeof(sa->vxrs_high));
 369                 ptr = nt_init(ptr, NT_S390_VXRS_LOW,
 370                               &sa->vxrs_low, sizeof(sa->vxrs_low));
 371         }
 372         return ptr;
 373 }
 374
 375 /*
 376  * Initialize prpsinfo note (new kernel)
 377  */
 378 static void *nt_prpsinfo(void *ptr)
 379 {
 380         struct elf_prpsinfo prpsinfo;
 381
 382         memset(&prpsinfo, 0, sizeof(prpsinfo));
 383         prpsinfo.pr_sname = 'R';
 384         strcpy(prpsinfo.pr_fname, "vmlinux");
 385         return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
 386 }
 387
 388 /*
 389  * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
 390  */
 391 static void *get_vmcoreinfo_old(unsigned long *size)
 392 {
 393         char nt_name[11], *vmcoreinfo;
 394         Elf64_Nhdr note;
 395         void *addr;
 396
 397         if (copy_oldmem_kernel(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
 398                 return NULL;
 399         memset(nt_name, 0, sizeof(nt_name));
 400         if (copy_oldmem_kernel(&note, addr, sizeof(note)))
 401                 return NULL;
 402         if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
 403                                sizeof(nt_name) - 1))
 404                 return NULL;
 405         if (strcmp(nt_name, "VMCOREINFO") != 0)
 406                 return NULL;
 407         vmcoreinfo = kzalloc_panic(note.n_descsz);
 408         if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz))
 409                 return NULL;
 410         *size = note.n_descsz;
 411         return vmcoreinfo;
 412 }
 413
 414 /*
 415  * Initialize vmcoreinfo note (new kernel)
 416  */
 417 static void *nt_vmcoreinfo(void *ptr)
 418 {
 419         unsigned long size;
 420         void *vmcoreinfo;
 421
 422         vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
 423         if (!vmcoreinfo)
 424                 vmcoreinfo = get_vmcoreinfo_old(&size);
 425         if (!vmcoreinfo)
 426                 return ptr;
 427         return nt_init_name(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
 428 }
 429
 430 /*
 431  * Initialize ELF header (new kernel)
 432  */
 433 static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
 434 {
 435         memset(ehdr, 0, sizeof(*ehdr));
 436         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
 437         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
 438         ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
 439         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
 440         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
 441         ehdr->e_type = ET_CORE;
 442         ehdr->e_machine = EM_S390;
 443         ehdr->e_version = EV_CURRENT;
 444         ehdr->e_phoff = sizeof(Elf64_Ehdr);
 445         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
 446         ehdr->e_phentsize = sizeof(Elf64_Phdr);
 447         ehdr->e_phnum = mem_chunk_cnt + 1;
 448         return ehdr + 1;
 449 }
 450
 451 /*
 452  * Return CPU count for ELF header (new kernel)
 453  */
 454 static int get_cpu_cnt(void)
 455 {
 456         struct save_area *sa;
 457         int cpus = 0;
 458
 459         list_for_each_entry(sa, &dump_save_areas, list)
 460                 if (sa->prefix != 0)
 461                         cpus++;
 462         return cpus;
 463 }
 464
 465 /*
 466  * Return memory chunk count for ELF header (new kernel)
 467  */
 468 static int get_mem_chunk_cnt(void)
 469 {
 470         int cnt = 0;
 471         u64 idx;
 472
 473         for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
 474                            MEMBLOCK_NONE, NULL, NULL, NULL)
 475                 cnt++;
 476         return cnt;
 477 }
 478
 479 /*
 480  * Initialize ELF loads (new kernel)
 481  */
 482 static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
 483 {
 484         phys_addr_t start, end;
 485         u64 idx;
 486
 487         for_each_mem_range(idx, &memblock.physmem, &oldmem_type, NUMA_NO_NODE,
 488                            MEMBLOCK_NONE, &start, &end, NULL) {
 489                 phdr->p_filesz = end - start;
 490                 phdr->p_type = PT_LOAD;
 491                 phdr->p_offset = start;
 492                 phdr->p_vaddr = start;
 493                 phdr->p_paddr = start;
 494                 phdr->p_memsz = end - start;
 495                 phdr->p_flags = PF_R | PF_W | PF_X;
 496                 phdr->p_align = PAGE_SIZE;
 497                 phdr++;
 498         }
 499 }
 500
 501 /*
 502  * Initialize notes (new kernel)
 503  */
 504 static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
 505 {
 506         struct save_area *sa;
 507         void *ptr_start = ptr;
 508         int cpu;
 509
 510         ptr = nt_prpsinfo(ptr);
 511
 512         cpu = 1;
 513         list_for_each_entry(sa, &dump_save_areas, list)
 514                 if (sa->prefix != 0)
 515                         ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
 516         ptr = nt_vmcoreinfo(ptr);
 517         memset(phdr, 0, sizeof(*phdr));
 518         phdr->p_type = PT_NOTE;
 519         phdr->p_offset = notes_offset;
 520         phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
 521         phdr->p_memsz = phdr->p_filesz;
 522         return ptr;
 523 }
 524
 525 /*
 526  * Create ELF core header (new kernel)
 527  */
 528 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
 529 {
 530         Elf64_Phdr *phdr_notes, *phdr_loads;
 531         int mem_chunk_cnt;
 532         void *ptr, *hdr;
 533         u32 alloc_size;
 534         u64 hdr_off;
 535
 536         /* If we are not in kdump or zfcpdump mode return */
 537         if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
 538                 return 0;
 539         /* If we cannot get HSA size for zfcpdump return error */
 540         if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp.hsa_size)
 541                 return -ENODEV;
 542
 543         /* For kdump, exclude previous crashkernel memory */
 544         if (OLDMEM_BASE) {
 545                 oldmem_region.base = OLDMEM_BASE;
 546                 oldmem_region.size = OLDMEM_SIZE;
 547                 oldmem_type.total_size = OLDMEM_SIZE;
 548         }
 549
 550         mem_chunk_cnt = get_mem_chunk_cnt();
 551
 552         alloc_size = 0x1000 + get_cpu_cnt() * 0x4a0 +
 553                 mem_chunk_cnt * sizeof(Elf64_Phdr);
 554         hdr = kzalloc_panic(alloc_size);
 555         /* Init elf header */
 556         ptr = ehdr_init(hdr, mem_chunk_cnt);
 557         /* Init program headers */
 558         phdr_notes = ptr;
 559         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
 560         phdr_loads = ptr;
 561         ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
 562         /* Init notes */
 563         hdr_off = PTR_DIFF(ptr, hdr);
 564         ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
 565         /* Init loads */
 566         hdr_off = PTR_DIFF(ptr, hdr);
 567         loads_init(phdr_loads, hdr_off);
 568         *addr = (unsigned long long) hdr;
 569         *size = (unsigned long long) hdr_off;
 570         BUG_ON(elfcorehdr_size > alloc_size);
 571         return 0;
 572 }
 573
 574 /*
 575  * Free ELF core header (new kernel)
 576  */
 577 void elfcorehdr_free(unsigned long long addr)
 578 {
 579         kfree((void *)(unsigned long)addr);
 580 }
 581
 582 /*
 583  * Read from ELF header
 584  */
 585 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 586 {
 587         void *src = (void *)(unsigned long)*ppos;
 588
 589         memcpy(buf, src, count);
 590         *ppos += count;
 591         return count;
 592 }
 593
 594 /*
 595  * Read from ELF notes data
 596  */
 597 ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
 598 {
 599         void *src = (void *)(unsigned long)*ppos;
 600
 601         memcpy(buf, src, count);
 602         *ppos += count;
 603         return count;
 604 }