1 /* 2 * Copyright (C) 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * Copyright (C) 2002-2006 Novell, Inc. 4 * Jan Beulich <jbeulich@novell.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * A simple API for unwinding kernel stacks. This is used for 11 * debugging and error reporting purposes. The kernel doesn't need 12 * full-blown stack unwinding with all the bells and whistles, so there 13 * is not much point in implementing the full Dwarf2 unwind API. 14 */ 15 16 #include <linux/sched.h> 17 #include <linux/module.h> 18 #include <linux/memblock.h> 19 #include <linux/sort.h> 20 #include <linux/slab.h> 21 #include <linux/stop_machine.h> 22 #include <linux/uaccess.h> 23 #include <linux/ptrace.h> 24 #include <asm/sections.h> 25 #include <asm/unaligned.h> 26 #include <asm/unwind.h> 27 28 extern char __start_unwind[], __end_unwind[]; 29 /* extern const u8 __start_unwind_hdr[], __end_unwind_hdr[];*/ 30 31 /* #define UNWIND_DEBUG */ 32 33 #ifdef UNWIND_DEBUG 34 int dbg_unw; 35 #define unw_debug(fmt, ...) \ 36 do { \ 37 if (dbg_unw) \ 38 pr_info(fmt, ##__VA_ARGS__); \ 39 } while (0); 40 #else 41 #define unw_debug(fmt, ...) 42 #endif 43 44 #define MAX_STACK_DEPTH 8 45 46 #define EXTRA_INFO(f) { \ 47 BUILD_BUG_ON_ZERO(offsetof(struct unwind_frame_info, f) \ 48 % FIELD_SIZEOF(struct unwind_frame_info, f)) \ 49 + offsetof(struct unwind_frame_info, f) \ 50 / FIELD_SIZEOF(struct unwind_frame_info, f), \ 51 FIELD_SIZEOF(struct unwind_frame_info, f) \ 52 } 53 #define PTREGS_INFO(f) EXTRA_INFO(regs.f) 54 55 static const struct { 56 unsigned offs:BITS_PER_LONG / 2; 57 unsigned width:BITS_PER_LONG / 2; 58 } reg_info[] = { 59 UNW_REGISTER_INFO}; 60 61 #undef PTREGS_INFO 62 #undef EXTRA_INFO 63 64 #ifndef REG_INVALID 65 #define REG_INVALID(r) (reg_info[r].width == 0) 66 #endif 67 68 #define DW_CFA_nop 0x00 69 #define DW_CFA_set_loc 0x01 70 #define DW_CFA_advance_loc1 0x02 71 #define DW_CFA_advance_loc2 0x03 72 #define DW_CFA_advance_loc4 0x04 73 #define DW_CFA_offset_extended 0x05 74 #define DW_CFA_restore_extended 0x06 75 #define DW_CFA_undefined 0x07 76 #define DW_CFA_same_value 0x08 77 #define DW_CFA_register 0x09 78 #define DW_CFA_remember_state 0x0a 79 #define DW_CFA_restore_state 0x0b 80 #define DW_CFA_def_cfa 0x0c 81 #define DW_CFA_def_cfa_register 0x0d 82 #define DW_CFA_def_cfa_offset 0x0e 83 #define DW_CFA_def_cfa_expression 0x0f 84 #define DW_CFA_expression 0x10 85 #define DW_CFA_offset_extended_sf 0x11 86 #define DW_CFA_def_cfa_sf 0x12 87 #define DW_CFA_def_cfa_offset_sf 0x13 88 #define DW_CFA_val_offset 0x14 89 #define DW_CFA_val_offset_sf 0x15 90 #define DW_CFA_val_expression 0x16 91 #define DW_CFA_lo_user 0x1c 92 #define DW_CFA_GNU_window_save 0x2d 93 #define DW_CFA_GNU_args_size 0x2e 94 #define DW_CFA_GNU_negative_offset_extended 0x2f 95 #define DW_CFA_hi_user 0x3f 96 97 #define DW_EH_PE_FORM 0x07 98 #define DW_EH_PE_native 0x00 99 #define DW_EH_PE_leb128 0x01 100 #define DW_EH_PE_data2 0x02 101 #define DW_EH_PE_data4 0x03 102 #define DW_EH_PE_data8 0x04 103 #define DW_EH_PE_signed 0x08 104 #define DW_EH_PE_ADJUST 0x70 105 #define DW_EH_PE_abs 0x00 106 #define DW_EH_PE_pcrel 0x10 107 #define DW_EH_PE_textrel 0x20 108 #define DW_EH_PE_datarel 0x30 109 #define DW_EH_PE_funcrel 0x40 110 #define DW_EH_PE_aligned 0x50 111 #define DW_EH_PE_indirect 0x80 112 #define DW_EH_PE_omit 0xff 113 114 #define CIE_ID 0 115 116 typedef unsigned long uleb128_t; 117 typedef signed long sleb128_t; 118 119 static struct unwind_table { 120 struct { 121 unsigned long pc; 122 unsigned long range; 123 } core, init; 124 const void *address; 125 unsigned long size; 126 const unsigned char *header; 127 unsigned long hdrsz; 128 struct unwind_table *link; 129 const char *name; 130 } root_table; 131 132 struct unwind_item { 133 enum item_location { 134 Nowhere, 135 Memory, 136 Register, 137 Value 138 } where; 139 uleb128_t value; 140 }; 141 142 struct unwind_state { 143 uleb128_t loc, org; 144 const u8 *cieStart, *cieEnd; 145 uleb128_t codeAlign; 146 sleb128_t dataAlign; 147 struct cfa { 148 uleb128_t reg, offs; 149 } cfa; 150 struct unwind_item regs[ARRAY_SIZE(reg_info)]; 151 unsigned stackDepth:8; 152 unsigned version:8; 153 const u8 *label; 154 const u8 *stack[MAX_STACK_DEPTH]; 155 }; 156 157 static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 }; 158 159 static struct unwind_table *find_table(unsigned long pc) 160 { 161 struct unwind_table *table; 162 163 for (table = &root_table; table; table = table->link) 164 if ((pc >= table->core.pc 165 && pc < table->core.pc + table->core.range) 166 || (pc >= table->init.pc 167 && pc < table->init.pc + table->init.range)) 168 break; 169 170 return table; 171 } 172 173 static unsigned long read_pointer(const u8 **pLoc, 174 const void *end, signed ptrType); 175 static void init_unwind_hdr(struct unwind_table *table, 176 void *(*alloc) (unsigned long)); 177 178 /* 179 * wrappers for header alloc (vs. calling one vs. other at call site) 180 * to elide section mismatches warnings 181 */ 182 static void *__init unw_hdr_alloc_early(unsigned long sz) 183 { 184 return memblock_alloc_from(sz, sizeof(unsigned int), MAX_DMA_ADDRESS); 185 } 186 187 static void *unw_hdr_alloc(unsigned long sz) 188 { 189 return kmalloc(sz, GFP_KERNEL); 190 } 191 192 static void init_unwind_table(struct unwind_table *table, const char *name, 193 const void *core_start, unsigned long core_size, 194 const void *init_start, unsigned long init_size, 195 const void *table_start, unsigned long table_size, 196 const u8 *header_start, unsigned long header_size) 197 { 198 const u8 *ptr = header_start + 4; 199 const u8 *end = header_start + header_size; 200 201 table->core.pc = (unsigned long)core_start; 202 table->core.range = core_size; 203 table->init.pc = (unsigned long)init_start; 204 table->init.range = init_size; 205 table->address = table_start; 206 table->size = table_size; 207 208 /* See if the linker provided table looks valid. */ 209 if (header_size <= 4 210 || header_start[0] != 1 211 || (void *)read_pointer(&ptr, end, header_start[1]) != table_start 212 || header_start[2] == DW_EH_PE_omit 213 || read_pointer(&ptr, end, header_start[2]) <= 0 214 || header_start[3] == DW_EH_PE_omit) 215 header_start = NULL; 216 217 table->hdrsz = header_size; 218 smp_wmb(); 219 table->header = header_start; 220 table->link = NULL; 221 table->name = name; 222 } 223 224 void __init arc_unwind_init(void) 225 { 226 init_unwind_table(&root_table, "kernel", _text, _end - _text, NULL, 0, 227 __start_unwind, __end_unwind - __start_unwind, 228 NULL, 0); 229 /*__start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr);*/ 230 231 init_unwind_hdr(&root_table, unw_hdr_alloc_early); 232 } 233 234 static const u32 bad_cie, not_fde; 235 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *); 236 static const u32 *__cie_for_fde(const u32 *fde); 237 static signed fde_pointer_type(const u32 *cie); 238 239 struct eh_frame_hdr_table_entry { 240 unsigned long start, fde; 241 }; 242 243 static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2) 244 { 245 const struct eh_frame_hdr_table_entry *e1 = p1; 246 const struct eh_frame_hdr_table_entry *e2 = p2; 247 248 return (e1->start > e2->start) - (e1->start < e2->start); 249 } 250 251 static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size) 252 { 253 struct eh_frame_hdr_table_entry *e1 = p1; 254 struct eh_frame_hdr_table_entry *e2 = p2; 255 unsigned long v; 256 257 v = e1->start; 258 e1->start = e2->start; 259 e2->start = v; 260 v = e1->fde; 261 e1->fde = e2->fde; 262 e2->fde = v; 263 } 264 265 static void init_unwind_hdr(struct unwind_table *table, 266 void *(*alloc) (unsigned long)) 267 { 268 const u8 *ptr; 269 unsigned long tableSize = table->size, hdrSize; 270 unsigned n; 271 const u32 *fde; 272 struct { 273 u8 version; 274 u8 eh_frame_ptr_enc; 275 u8 fde_count_enc; 276 u8 table_enc; 277 unsigned long eh_frame_ptr; 278 unsigned int fde_count; 279 struct eh_frame_hdr_table_entry table[]; 280 } __attribute__ ((__packed__)) *header; 281 282 if (table->header) 283 return; 284 285 if (table->hdrsz) 286 pr_warn(".eh_frame_hdr for '%s' present but unusable\n", 287 table->name); 288 289 if (tableSize & (sizeof(*fde) - 1)) 290 return; 291 292 for (fde = table->address, n = 0; 293 tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde; 294 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { 295 const u32 *cie = cie_for_fde(fde, table); 296 signed ptrType; 297 298 if (cie == ¬_fde) 299 continue; 300 if (cie == NULL || cie == &bad_cie) 301 goto ret_err; 302 ptrType = fde_pointer_type(cie); 303 if (ptrType < 0) 304 goto ret_err; 305 306 ptr = (const u8 *)(fde + 2); 307 if (!read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, 308 ptrType)) { 309 /* FIXME_Rajesh We have 4 instances of null addresses 310 * instead of the initial loc addr 311 * return; 312 */ 313 WARN(1, "unwinder: FDE->initial_location NULL %p\n", 314 (const u8 *)(fde + 1) + *fde); 315 } 316 ++n; 317 } 318 319 if (tableSize || !n) 320 goto ret_err; 321 322 hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int) 323 + 2 * n * sizeof(unsigned long); 324 325 header = alloc(hdrSize); 326 if (!header) 327 goto ret_err; 328 329 header->version = 1; 330 header->eh_frame_ptr_enc = DW_EH_PE_abs | DW_EH_PE_native; 331 header->fde_count_enc = DW_EH_PE_abs | DW_EH_PE_data4; 332 header->table_enc = DW_EH_PE_abs | DW_EH_PE_native; 333 put_unaligned((unsigned long)table->address, &header->eh_frame_ptr); 334 BUILD_BUG_ON(offsetof(typeof(*header), fde_count) 335 % __alignof(typeof(header->fde_count))); 336 header->fde_count = n; 337 338 BUILD_BUG_ON(offsetof(typeof(*header), table) 339 % __alignof(typeof(*header->table))); 340 for (fde = table->address, tableSize = table->size, n = 0; 341 tableSize; 342 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { 343 const u32 *cie = __cie_for_fde(fde); 344 345 if (fde[1] == CIE_ID) 346 continue; /* this is a CIE */ 347 ptr = (const u8 *)(fde + 2); 348 header->table[n].start = read_pointer(&ptr, 349 (const u8 *)(fde + 1) + 350 *fde, 351 fde_pointer_type(cie)); 352 header->table[n].fde = (unsigned long)fde; 353 ++n; 354 } 355 WARN_ON(n != header->fde_count); 356 357 sort(header->table, 358 n, 359 sizeof(*header->table), 360 cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries); 361 362 table->hdrsz = hdrSize; 363 smp_wmb(); 364 table->header = (const void *)header; 365 return; 366 367 ret_err: 368 panic("Attention !!! Dwarf FDE parsing errors\n"); 369 } 370 371 #ifdef CONFIG_MODULES 372 373 static struct unwind_table *last_table; 374 375 /* Must be called with module_mutex held. */ 376 void *unwind_add_table(struct module *module, const void *table_start, 377 unsigned long table_size) 378 { 379 struct unwind_table *table; 380 381 if (table_size <= 0) 382 return NULL; 383 384 table = kmalloc(sizeof(*table), GFP_KERNEL); 385 if (!table) 386 return NULL; 387 388 init_unwind_table(table, module->name, 389 module->core_layout.base, module->core_layout.size, 390 module->init_layout.base, module->init_layout.size, 391 table_start, table_size, 392 NULL, 0); 393 394 init_unwind_hdr(table, unw_hdr_alloc); 395 396 #ifdef UNWIND_DEBUG 397 unw_debug("Table added for [%s] %lx %lx\n", 398 module->name, table->core.pc, table->core.range); 399 #endif 400 if (last_table) 401 last_table->link = table; 402 else 403 root_table.link = table; 404 last_table = table; 405 406 return table; 407 } 408 409 struct unlink_table_info { 410 struct unwind_table *table; 411 int init_only; 412 }; 413 414 static int unlink_table(void *arg) 415 { 416 struct unlink_table_info *info = arg; 417 struct unwind_table *table = info->table, *prev; 418 419 for (prev = &root_table; prev->link && prev->link != table; 420 prev = prev->link) 421 ; 422 423 if (prev->link) { 424 if (info->init_only) { 425 table->init.pc = 0; 426 table->init.range = 0; 427 info->table = NULL; 428 } else { 429 prev->link = table->link; 430 if (!prev->link) 431 last_table = prev; 432 } 433 } else 434 info->table = NULL; 435 436 return 0; 437 } 438 439 /* Must be called with module_mutex held. */ 440 void unwind_remove_table(void *handle, int init_only) 441 { 442 struct unwind_table *table = handle; 443 struct unlink_table_info info; 444 445 if (!table || table == &root_table) 446 return; 447 448 if (init_only && table == last_table) { 449 table->init.pc = 0; 450 table->init.range = 0; 451 return; 452 } 453 454 info.table = table; 455 info.init_only = init_only; 456 457 unlink_table(&info); /* XXX: SMP */ 458 kfree(table->header); 459 kfree(table); 460 } 461 462 #endif /* CONFIG_MODULES */ 463 464 static uleb128_t get_uleb128(const u8 **pcur, const u8 *end) 465 { 466 const u8 *cur = *pcur; 467 uleb128_t value; 468 unsigned shift; 469 470 for (shift = 0, value = 0; cur < end; shift += 7) { 471 if (shift + 7 > 8 * sizeof(value) 472 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) { 473 cur = end + 1; 474 break; 475 } 476 value |= (uleb128_t) (*cur & 0x7f) << shift; 477 if (!(*cur++ & 0x80)) 478 break; 479 } 480 *pcur = cur; 481 482 return value; 483 } 484 485 static sleb128_t get_sleb128(const u8 **pcur, const u8 *end) 486 { 487 const u8 *cur = *pcur; 488 sleb128_t value; 489 unsigned shift; 490 491 for (shift = 0, value = 0; cur < end; shift += 7) { 492 if (shift + 7 > 8 * sizeof(value) 493 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) { 494 cur = end + 1; 495 break; 496 } 497 value |= (sleb128_t) (*cur & 0x7f) << shift; 498 if (!(*cur & 0x80)) { 499 value |= -(*cur++ & 0x40) << shift; 500 break; 501 } 502 } 503 *pcur = cur; 504 505 return value; 506 } 507 508 static const u32 *__cie_for_fde(const u32 *fde) 509 { 510 const u32 *cie; 511 512 cie = fde + 1 - fde[1] / sizeof(*fde); 513 514 return cie; 515 } 516 517 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table) 518 { 519 const u32 *cie; 520 521 if (!*fde || (*fde & (sizeof(*fde) - 1))) 522 return &bad_cie; 523 524 if (fde[1] == CIE_ID) 525 return ¬_fde; /* this is a CIE */ 526 527 if ((fde[1] & (sizeof(*fde) - 1))) 528 /* || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address) */ 529 return NULL; /* this is not a valid FDE */ 530 531 cie = __cie_for_fde(fde); 532 533 if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde) 534 || (*cie & (sizeof(*cie) - 1)) 535 || (cie[1] != CIE_ID)) 536 return NULL; /* this is not a (valid) CIE */ 537 return cie; 538 } 539 540 static unsigned long read_pointer(const u8 **pLoc, const void *end, 541 signed ptrType) 542 { 543 unsigned long value = 0; 544 union { 545 const u8 *p8; 546 const u16 *p16u; 547 const s16 *p16s; 548 const u32 *p32u; 549 const s32 *p32s; 550 const unsigned long *pul; 551 } ptr; 552 553 if (ptrType < 0 || ptrType == DW_EH_PE_omit) 554 return 0; 555 ptr.p8 = *pLoc; 556 switch (ptrType & DW_EH_PE_FORM) { 557 case DW_EH_PE_data2: 558 if (end < (const void *)(ptr.p16u + 1)) 559 return 0; 560 if (ptrType & DW_EH_PE_signed) 561 value = get_unaligned((u16 *) ptr.p16s++); 562 else 563 value = get_unaligned((u16 *) ptr.p16u++); 564 break; 565 case DW_EH_PE_data4: 566 #ifdef CONFIG_64BIT 567 if (end < (const void *)(ptr.p32u + 1)) 568 return 0; 569 if (ptrType & DW_EH_PE_signed) 570 value = get_unaligned(ptr.p32s++); 571 else 572 value = get_unaligned(ptr.p32u++); 573 break; 574 case DW_EH_PE_data8: 575 BUILD_BUG_ON(sizeof(u64) != sizeof(value)); 576 #else 577 BUILD_BUG_ON(sizeof(u32) != sizeof(value)); 578 #endif 579 case DW_EH_PE_native: 580 if (end < (const void *)(ptr.pul + 1)) 581 return 0; 582 value = get_unaligned((unsigned long *)ptr.pul++); 583 break; 584 case DW_EH_PE_leb128: 585 BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value)); 586 value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end) 587 : get_uleb128(&ptr.p8, end); 588 if ((const void *)ptr.p8 > end) 589 return 0; 590 break; 591 default: 592 return 0; 593 } 594 switch (ptrType & DW_EH_PE_ADJUST) { 595 case DW_EH_PE_abs: 596 break; 597 case DW_EH_PE_pcrel: 598 value += (unsigned long)*pLoc; 599 break; 600 default: 601 return 0; 602 } 603 if ((ptrType & DW_EH_PE_indirect) 604 && __get_user(value, (unsigned long __user *)value)) 605 return 0; 606 *pLoc = ptr.p8; 607 608 return value; 609 } 610 611 static signed fde_pointer_type(const u32 *cie) 612 { 613 const u8 *ptr = (const u8 *)(cie + 2); 614 unsigned version = *ptr; 615 616 if (*++ptr) { 617 const char *aug; 618 const u8 *end = (const u8 *)(cie + 1) + *cie; 619 uleb128_t len; 620 621 /* check if augmentation size is first (and thus present) */ 622 if (*ptr != 'z') 623 return -1; 624 625 /* check if augmentation string is nul-terminated */ 626 aug = (const void *)ptr; 627 ptr = memchr(aug, 0, end - ptr); 628 if (ptr == NULL) 629 return -1; 630 631 ++ptr; /* skip terminator */ 632 get_uleb128(&ptr, end); /* skip code alignment */ 633 get_sleb128(&ptr, end); /* skip data alignment */ 634 /* skip return address column */ 635 version <= 1 ? (void) ++ptr : (void)get_uleb128(&ptr, end); 636 len = get_uleb128(&ptr, end); /* augmentation length */ 637 638 if (ptr + len < ptr || ptr + len > end) 639 return -1; 640 641 end = ptr + len; 642 while (*++aug) { 643 if (ptr >= end) 644 return -1; 645 switch (*aug) { 646 case 'L': 647 ++ptr; 648 break; 649 case 'P':{ 650 signed ptrType = *ptr++; 651 652 if (!read_pointer(&ptr, end, ptrType) 653 || ptr > end) 654 return -1; 655 } 656 break; 657 case 'R': 658 return *ptr; 659 default: 660 return -1; 661 } 662 } 663 } 664 return DW_EH_PE_native | DW_EH_PE_abs; 665 } 666 667 static int advance_loc(unsigned long delta, struct unwind_state *state) 668 { 669 state->loc += delta * state->codeAlign; 670 671 /* FIXME_Rajesh: Probably we are defining for the initial range as well; 672 return delta > 0; 673 */ 674 unw_debug("delta %3lu => loc 0x%lx: ", delta, state->loc); 675 return 1; 676 } 677 678 static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value, 679 struct unwind_state *state) 680 { 681 if (reg < ARRAY_SIZE(state->regs)) { 682 state->regs[reg].where = where; 683 state->regs[reg].value = value; 684 685 #ifdef UNWIND_DEBUG 686 unw_debug("r%lu: ", reg); 687 switch (where) { 688 case Nowhere: 689 unw_debug("s "); 690 break; 691 case Memory: 692 unw_debug("c(%lu) ", value); 693 break; 694 case Register: 695 unw_debug("r(%lu) ", value); 696 break; 697 case Value: 698 unw_debug("v(%lu) ", value); 699 break; 700 default: 701 break; 702 } 703 #endif 704 } 705 } 706 707 static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc, 708 signed ptrType, struct unwind_state *state) 709 { 710 union { 711 const u8 *p8; 712 const u16 *p16; 713 const u32 *p32; 714 } ptr; 715 int result = 1; 716 u8 opcode; 717 718 if (start != state->cieStart) { 719 state->loc = state->org; 720 result = 721 processCFI(state->cieStart, state->cieEnd, 0, ptrType, 722 state); 723 if (targetLoc == 0 && state->label == NULL) 724 return result; 725 } 726 for (ptr.p8 = start; result && ptr.p8 < end;) { 727 switch (*ptr.p8 >> 6) { 728 uleb128_t value; 729 730 case 0: 731 opcode = *ptr.p8++; 732 733 switch (opcode) { 734 case DW_CFA_nop: 735 unw_debug("cfa nop "); 736 break; 737 case DW_CFA_set_loc: 738 state->loc = read_pointer(&ptr.p8, end, 739 ptrType); 740 if (state->loc == 0) 741 result = 0; 742 unw_debug("cfa_set_loc: 0x%lx ", state->loc); 743 break; 744 case DW_CFA_advance_loc1: 745 unw_debug("\ncfa advance loc1:"); 746 result = ptr.p8 < end 747 && advance_loc(*ptr.p8++, state); 748 break; 749 case DW_CFA_advance_loc2: 750 value = *ptr.p8++; 751 value += *ptr.p8++ << 8; 752 unw_debug("\ncfa advance loc2:"); 753 result = ptr.p8 <= end + 2 754 /* && advance_loc(*ptr.p16++, state); */ 755 && advance_loc(value, state); 756 break; 757 case DW_CFA_advance_loc4: 758 unw_debug("\ncfa advance loc4:"); 759 result = ptr.p8 <= end + 4 760 && advance_loc(*ptr.p32++, state); 761 break; 762 case DW_CFA_offset_extended: 763 value = get_uleb128(&ptr.p8, end); 764 unw_debug("cfa_offset_extended: "); 765 set_rule(value, Memory, 766 get_uleb128(&ptr.p8, end), state); 767 break; 768 case DW_CFA_val_offset: 769 value = get_uleb128(&ptr.p8, end); 770 set_rule(value, Value, 771 get_uleb128(&ptr.p8, end), state); 772 break; 773 case DW_CFA_offset_extended_sf: 774 value = get_uleb128(&ptr.p8, end); 775 set_rule(value, Memory, 776 get_sleb128(&ptr.p8, end), state); 777 break; 778 case DW_CFA_val_offset_sf: 779 value = get_uleb128(&ptr.p8, end); 780 set_rule(value, Value, 781 get_sleb128(&ptr.p8, end), state); 782 break; 783 case DW_CFA_restore_extended: 784 unw_debug("cfa_restore_extended: "); 785 case DW_CFA_undefined: 786 unw_debug("cfa_undefined: "); 787 case DW_CFA_same_value: 788 unw_debug("cfa_same_value: "); 789 set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0, 790 state); 791 break; 792 case DW_CFA_register: 793 unw_debug("cfa_register: "); 794 value = get_uleb128(&ptr.p8, end); 795 set_rule(value, 796 Register, 797 get_uleb128(&ptr.p8, end), state); 798 break; 799 case DW_CFA_remember_state: 800 unw_debug("cfa_remember_state: "); 801 if (ptr.p8 == state->label) { 802 state->label = NULL; 803 return 1; 804 } 805 if (state->stackDepth >= MAX_STACK_DEPTH) 806 return 0; 807 state->stack[state->stackDepth++] = ptr.p8; 808 break; 809 case DW_CFA_restore_state: 810 unw_debug("cfa_restore_state: "); 811 if (state->stackDepth) { 812 const uleb128_t loc = state->loc; 813 const u8 *label = state->label; 814 815 state->label = 816 state->stack[state->stackDepth - 1]; 817 memcpy(&state->cfa, &badCFA, 818 sizeof(state->cfa)); 819 memset(state->regs, 0, 820 sizeof(state->regs)); 821 state->stackDepth = 0; 822 result = 823 processCFI(start, end, 0, ptrType, 824 state); 825 state->loc = loc; 826 state->label = label; 827 } else 828 return 0; 829 break; 830 case DW_CFA_def_cfa: 831 state->cfa.reg = get_uleb128(&ptr.p8, end); 832 unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg); 833 /*nobreak*/ 834 case DW_CFA_def_cfa_offset: 835 state->cfa.offs = get_uleb128(&ptr.p8, end); 836 unw_debug("cfa_def_cfa_offset: 0x%lx ", 837 state->cfa.offs); 838 break; 839 case DW_CFA_def_cfa_sf: 840 state->cfa.reg = get_uleb128(&ptr.p8, end); 841 /*nobreak */ 842 case DW_CFA_def_cfa_offset_sf: 843 state->cfa.offs = get_sleb128(&ptr.p8, end) 844 * state->dataAlign; 845 break; 846 case DW_CFA_def_cfa_register: 847 unw_debug("cfa_def_cfa_register: "); 848 state->cfa.reg = get_uleb128(&ptr.p8, end); 849 break; 850 /*todo case DW_CFA_def_cfa_expression: */ 851 /*todo case DW_CFA_expression: */ 852 /*todo case DW_CFA_val_expression: */ 853 case DW_CFA_GNU_args_size: 854 get_uleb128(&ptr.p8, end); 855 break; 856 case DW_CFA_GNU_negative_offset_extended: 857 value = get_uleb128(&ptr.p8, end); 858 set_rule(value, 859 Memory, 860 (uleb128_t) 0 - get_uleb128(&ptr.p8, 861 end), 862 state); 863 break; 864 case DW_CFA_GNU_window_save: 865 default: 866 unw_debug("UNKNOWN OPCODE 0x%x\n", opcode); 867 result = 0; 868 break; 869 } 870 break; 871 case 1: 872 unw_debug("\ncfa_adv_loc: "); 873 result = advance_loc(*ptr.p8++ & 0x3f, state); 874 break; 875 case 2: 876 unw_debug("cfa_offset: "); 877 value = *ptr.p8++ & 0x3f; 878 set_rule(value, Memory, get_uleb128(&ptr.p8, end), 879 state); 880 break; 881 case 3: 882 unw_debug("cfa_restore: "); 883 set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state); 884 break; 885 } 886 887 if (ptr.p8 > end) 888 result = 0; 889 if (result && targetLoc != 0 && targetLoc < state->loc) 890 return 1; 891 } 892 893 return result && ptr.p8 == end && (targetLoc == 0 || ( 894 /*todo While in theory this should apply, gcc in practice omits 895 everything past the function prolog, and hence the location 896 never reaches the end of the function. 897 targetLoc < state->loc && */ state->label == NULL)); 898 } 899 900 /* Unwind to previous to frame. Returns 0 if successful, negative 901 * number in case of an error. */ 902 int arc_unwind(struct unwind_frame_info *frame) 903 { 904 #define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs]) 905 const u32 *fde = NULL, *cie = NULL; 906 const u8 *ptr = NULL, *end = NULL; 907 unsigned long pc = UNW_PC(frame) - frame->call_frame; 908 unsigned long startLoc = 0, endLoc = 0, cfa; 909 unsigned i; 910 signed ptrType = -1; 911 uleb128_t retAddrReg = 0; 912 const struct unwind_table *table; 913 struct unwind_state state; 914 unsigned long *fptr; 915 unsigned long addr; 916 917 unw_debug("\n\nUNWIND FRAME:\n"); 918 unw_debug("PC: 0x%lx BLINK: 0x%lx, SP: 0x%lx, FP: 0x%x\n", 919 UNW_PC(frame), UNW_BLINK(frame), UNW_SP(frame), 920 UNW_FP(frame)); 921 922 if (UNW_PC(frame) == 0) 923 return -EINVAL; 924 925 #ifdef UNWIND_DEBUG 926 { 927 unsigned long *sptr = (unsigned long *)UNW_SP(frame); 928 unw_debug("\nStack Dump:\n"); 929 for (i = 0; i < 20; i++, sptr++) 930 unw_debug("0x%p: 0x%lx\n", sptr, *sptr); 931 unw_debug("\n"); 932 } 933 #endif 934 935 table = find_table(pc); 936 if (table != NULL 937 && !(table->size & (sizeof(*fde) - 1))) { 938 const u8 *hdr = table->header; 939 unsigned long tableSize; 940 941 smp_rmb(); 942 if (hdr && hdr[0] == 1) { 943 switch (hdr[3] & DW_EH_PE_FORM) { 944 case DW_EH_PE_native: 945 tableSize = sizeof(unsigned long); 946 break; 947 case DW_EH_PE_data2: 948 tableSize = 2; 949 break; 950 case DW_EH_PE_data4: 951 tableSize = 4; 952 break; 953 case DW_EH_PE_data8: 954 tableSize = 8; 955 break; 956 default: 957 tableSize = 0; 958 break; 959 } 960 ptr = hdr + 4; 961 end = hdr + table->hdrsz; 962 if (tableSize && read_pointer(&ptr, end, hdr[1]) 963 == (unsigned long)table->address 964 && (i = read_pointer(&ptr, end, hdr[2])) > 0 965 && i == (end - ptr) / (2 * tableSize) 966 && !((end - ptr) % (2 * tableSize))) { 967 do { 968 const u8 *cur = 969 ptr + (i / 2) * (2 * tableSize); 970 971 startLoc = read_pointer(&cur, 972 cur + tableSize, 973 hdr[3]); 974 if (pc < startLoc) 975 i /= 2; 976 else { 977 ptr = cur - tableSize; 978 i = (i + 1) / 2; 979 } 980 } while (startLoc && i > 1); 981 if (i == 1 982 && (startLoc = read_pointer(&ptr, 983 ptr + tableSize, 984 hdr[3])) != 0 985 && pc >= startLoc) 986 fde = (void *)read_pointer(&ptr, 987 ptr + 988 tableSize, 989 hdr[3]); 990 } 991 } 992 993 if (fde != NULL) { 994 cie = cie_for_fde(fde, table); 995 ptr = (const u8 *)(fde + 2); 996 if (cie != NULL 997 && cie != &bad_cie 998 && cie != ¬_fde 999 && (ptrType = fde_pointer_type(cie)) >= 0 1000 && read_pointer(&ptr, 1001 (const u8 *)(fde + 1) + *fde, 1002 ptrType) == startLoc) { 1003 if (!(ptrType & DW_EH_PE_indirect)) 1004 ptrType &= 1005 DW_EH_PE_FORM | DW_EH_PE_signed; 1006 endLoc = 1007 startLoc + read_pointer(&ptr, 1008 (const u8 *)(fde + 1009 1) + 1010 *fde, ptrType); 1011 if (pc >= endLoc) { 1012 fde = NULL; 1013 cie = NULL; 1014 } 1015 } else { 1016 fde = NULL; 1017 cie = NULL; 1018 } 1019 } 1020 } 1021 if (cie != NULL) { 1022 memset(&state, 0, sizeof(state)); 1023 state.cieEnd = ptr; /* keep here temporarily */ 1024 ptr = (const u8 *)(cie + 2); 1025 end = (const u8 *)(cie + 1) + *cie; 1026 frame->call_frame = 1; 1027 if (*++ptr) { 1028 /* check if augmentation size is first (thus present) */ 1029 if (*ptr == 'z') { 1030 while (++ptr < end && *ptr) { 1031 switch (*ptr) { 1032 /* chk for ignorable or already handled 1033 * nul-terminated augmentation string */ 1034 case 'L': 1035 case 'P': 1036 case 'R': 1037 continue; 1038 case 'S': 1039 frame->call_frame = 0; 1040 continue; 1041 default: 1042 break; 1043 } 1044 break; 1045 } 1046 } 1047 if (ptr >= end || *ptr) 1048 cie = NULL; 1049 } 1050 ++ptr; 1051 } 1052 if (cie != NULL) { 1053 /* get code alignment factor */ 1054 state.codeAlign = get_uleb128(&ptr, end); 1055 /* get data alignment factor */ 1056 state.dataAlign = get_sleb128(&ptr, end); 1057 if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end) 1058 cie = NULL; 1059 else { 1060 retAddrReg = 1061 state.version <= 1 ? *ptr++ : get_uleb128(&ptr, 1062 end); 1063 unw_debug("CIE Frame Info:\n"); 1064 unw_debug("return Address register 0x%lx\n", 1065 retAddrReg); 1066 unw_debug("data Align: %ld\n", state.dataAlign); 1067 unw_debug("code Align: %lu\n", state.codeAlign); 1068 /* skip augmentation */ 1069 if (((const char *)(cie + 2))[1] == 'z') { 1070 uleb128_t augSize = get_uleb128(&ptr, end); 1071 1072 ptr += augSize; 1073 } 1074 if (ptr > end || retAddrReg >= ARRAY_SIZE(reg_info) 1075 || REG_INVALID(retAddrReg) 1076 || reg_info[retAddrReg].width != 1077 sizeof(unsigned long)) 1078 cie = NULL; 1079 } 1080 } 1081 if (cie != NULL) { 1082 state.cieStart = ptr; 1083 ptr = state.cieEnd; 1084 state.cieEnd = end; 1085 end = (const u8 *)(fde + 1) + *fde; 1086 /* skip augmentation */ 1087 if (((const char *)(cie + 2))[1] == 'z') { 1088 uleb128_t augSize = get_uleb128(&ptr, end); 1089 1090 if ((ptr += augSize) > end) 1091 fde = NULL; 1092 } 1093 } 1094 if (cie == NULL || fde == NULL) { 1095 #ifdef CONFIG_FRAME_POINTER 1096 unsigned long top, bottom; 1097 1098 top = STACK_TOP_UNW(frame->task); 1099 bottom = STACK_BOTTOM_UNW(frame->task); 1100 #if FRAME_RETADDR_OFFSET < 0 1101 if (UNW_SP(frame) < top && UNW_FP(frame) <= UNW_SP(frame) 1102 && bottom < UNW_FP(frame) 1103 #else 1104 if (UNW_SP(frame) > top && UNW_FP(frame) >= UNW_SP(frame) 1105 && bottom > UNW_FP(frame) 1106 #endif 1107 && !((UNW_SP(frame) | UNW_FP(frame)) 1108 & (sizeof(unsigned long) - 1))) { 1109 unsigned long link; 1110 1111 if (!__get_user(link, (unsigned long *) 1112 (UNW_FP(frame) + FRAME_LINK_OFFSET)) 1113 #if FRAME_RETADDR_OFFSET < 0 1114 && link > bottom && link < UNW_FP(frame) 1115 #else 1116 && link > UNW_FP(frame) && link < bottom 1117 #endif 1118 && !(link & (sizeof(link) - 1)) 1119 && !__get_user(UNW_PC(frame), 1120 (unsigned long *)(UNW_FP(frame) 1121 + FRAME_RETADDR_OFFSET))) 1122 { 1123 UNW_SP(frame) = 1124 UNW_FP(frame) + FRAME_RETADDR_OFFSET 1125 #if FRAME_RETADDR_OFFSET < 0 1126 - 1127 #else 1128 + 1129 #endif 1130 sizeof(UNW_PC(frame)); 1131 UNW_FP(frame) = link; 1132 return 0; 1133 } 1134 } 1135 #endif 1136 return -ENXIO; 1137 } 1138 state.org = startLoc; 1139 memcpy(&state.cfa, &badCFA, sizeof(state.cfa)); 1140 1141 unw_debug("\nProcess instructions\n"); 1142 1143 /* process instructions 1144 * For ARC, we optimize by having blink(retAddrReg) with 1145 * the sameValue in the leaf function, so we should not check 1146 * state.regs[retAddrReg].where == Nowhere 1147 */ 1148 if (!processCFI(ptr, end, pc, ptrType, &state) 1149 || state.loc > endLoc 1150 /* || state.regs[retAddrReg].where == Nowhere */ 1151 || state.cfa.reg >= ARRAY_SIZE(reg_info) 1152 || reg_info[state.cfa.reg].width != sizeof(unsigned long) 1153 || state.cfa.offs % sizeof(unsigned long)) 1154 return -EIO; 1155 1156 #ifdef UNWIND_DEBUG 1157 unw_debug("\n"); 1158 1159 unw_debug("\nRegister State Based on the rules parsed from FDE:\n"); 1160 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) { 1161 1162 if (REG_INVALID(i)) 1163 continue; 1164 1165 switch (state.regs[i].where) { 1166 case Nowhere: 1167 break; 1168 case Memory: 1169 unw_debug(" r%d: c(%lu),", i, state.regs[i].value); 1170 break; 1171 case Register: 1172 unw_debug(" r%d: r(%lu),", i, state.regs[i].value); 1173 break; 1174 case Value: 1175 unw_debug(" r%d: v(%lu),", i, state.regs[i].value); 1176 break; 1177 } 1178 } 1179 1180 unw_debug("\n"); 1181 #endif 1182 1183 /* update frame */ 1184 #ifndef CONFIG_AS_CFI_SIGNAL_FRAME 1185 if (frame->call_frame 1186 && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign)) 1187 frame->call_frame = 0; 1188 #endif 1189 cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs; 1190 startLoc = min_t(unsigned long, UNW_SP(frame), cfa); 1191 endLoc = max_t(unsigned long, UNW_SP(frame), cfa); 1192 if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) { 1193 startLoc = min(STACK_LIMIT(cfa), cfa); 1194 endLoc = max(STACK_LIMIT(cfa), cfa); 1195 } 1196 1197 unw_debug("\nCFA reg: 0x%lx, offset: 0x%lx => 0x%lx\n", 1198 state.cfa.reg, state.cfa.offs, cfa); 1199 1200 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) { 1201 if (REG_INVALID(i)) { 1202 if (state.regs[i].where == Nowhere) 1203 continue; 1204 return -EIO; 1205 } 1206 switch (state.regs[i].where) { 1207 default: 1208 break; 1209 case Register: 1210 if (state.regs[i].value >= ARRAY_SIZE(reg_info) 1211 || REG_INVALID(state.regs[i].value) 1212 || reg_info[i].width > 1213 reg_info[state.regs[i].value].width) 1214 return -EIO; 1215 switch (reg_info[state.regs[i].value].width) { 1216 case sizeof(u8): 1217 state.regs[i].value = 1218 FRAME_REG(state.regs[i].value, const u8); 1219 break; 1220 case sizeof(u16): 1221 state.regs[i].value = 1222 FRAME_REG(state.regs[i].value, const u16); 1223 break; 1224 case sizeof(u32): 1225 state.regs[i].value = 1226 FRAME_REG(state.regs[i].value, const u32); 1227 break; 1228 #ifdef CONFIG_64BIT 1229 case sizeof(u64): 1230 state.regs[i].value = 1231 FRAME_REG(state.regs[i].value, const u64); 1232 break; 1233 #endif 1234 default: 1235 return -EIO; 1236 } 1237 break; 1238 } 1239 } 1240 1241 unw_debug("\nRegister state after evaluation with realtime Stack:\n"); 1242 fptr = (unsigned long *)(&frame->regs); 1243 for (i = 0; i < ARRAY_SIZE(state.regs); ++i, fptr++) { 1244 1245 if (REG_INVALID(i)) 1246 continue; 1247 switch (state.regs[i].where) { 1248 case Nowhere: 1249 if (reg_info[i].width != sizeof(UNW_SP(frame)) 1250 || &FRAME_REG(i, __typeof__(UNW_SP(frame))) 1251 != &UNW_SP(frame)) 1252 continue; 1253 UNW_SP(frame) = cfa; 1254 break; 1255 case Register: 1256 switch (reg_info[i].width) { 1257 case sizeof(u8): 1258 FRAME_REG(i, u8) = state.regs[i].value; 1259 break; 1260 case sizeof(u16): 1261 FRAME_REG(i, u16) = state.regs[i].value; 1262 break; 1263 case sizeof(u32): 1264 FRAME_REG(i, u32) = state.regs[i].value; 1265 break; 1266 #ifdef CONFIG_64BIT 1267 case sizeof(u64): 1268 FRAME_REG(i, u64) = state.regs[i].value; 1269 break; 1270 #endif 1271 default: 1272 return -EIO; 1273 } 1274 break; 1275 case Value: 1276 if (reg_info[i].width != sizeof(unsigned long)) 1277 return -EIO; 1278 FRAME_REG(i, unsigned long) = cfa + state.regs[i].value 1279 * state.dataAlign; 1280 break; 1281 case Memory: 1282 addr = cfa + state.regs[i].value * state.dataAlign; 1283 1284 if ((state.regs[i].value * state.dataAlign) 1285 % sizeof(unsigned long) 1286 || addr < startLoc 1287 || addr + sizeof(unsigned long) < addr 1288 || addr + sizeof(unsigned long) > endLoc) 1289 return -EIO; 1290 1291 switch (reg_info[i].width) { 1292 case sizeof(u8): 1293 __get_user(FRAME_REG(i, u8), 1294 (u8 __user *)addr); 1295 break; 1296 case sizeof(u16): 1297 __get_user(FRAME_REG(i, u16), 1298 (u16 __user *)addr); 1299 break; 1300 case sizeof(u32): 1301 __get_user(FRAME_REG(i, u32), 1302 (u32 __user *)addr); 1303 break; 1304 #ifdef CONFIG_64BIT 1305 case sizeof(u64): 1306 __get_user(FRAME_REG(i, u64), 1307 (u64 __user *)addr); 1308 break; 1309 #endif 1310 default: 1311 return -EIO; 1312 } 1313 1314 break; 1315 } 1316 unw_debug("r%d: 0x%lx ", i, *fptr); 1317 } 1318 1319 return 0; 1320 #undef FRAME_REG 1321 } 1322 EXPORT_SYMBOL(arc_unwind); 1323