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