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