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(¬e, 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 } 604