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/bootmem.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 typedef unsigned long uleb128_t; 115 typedef signed long sleb128_t; 116 117 static struct unwind_table { 118 struct { 119 unsigned long pc; 120 unsigned long range; 121 } core, init; 122 const void *address; 123 unsigned long size; 124 const unsigned char *header; 125 unsigned long hdrsz; 126 struct unwind_table *link; 127 const char *name; 128 } root_table; 129 130 struct unwind_item { 131 enum item_location { 132 Nowhere, 133 Memory, 134 Register, 135 Value 136 } where; 137 uleb128_t value; 138 }; 139 140 struct unwind_state { 141 uleb128_t loc, org; 142 const u8 *cieStart, *cieEnd; 143 uleb128_t codeAlign; 144 sleb128_t dataAlign; 145 struct cfa { 146 uleb128_t reg, offs; 147 } cfa; 148 struct unwind_item regs[ARRAY_SIZE(reg_info)]; 149 unsigned stackDepth:8; 150 unsigned version:8; 151 const u8 *label; 152 const u8 *stack[MAX_STACK_DEPTH]; 153 }; 154 155 static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 }; 156 157 static struct unwind_table *find_table(unsigned long pc) 158 { 159 struct unwind_table *table; 160 161 for (table = &root_table; table; table = table->link) 162 if ((pc >= table->core.pc 163 && pc < table->core.pc + table->core.range) 164 || (pc >= table->init.pc 165 && pc < table->init.pc + table->init.range)) 166 break; 167 168 return table; 169 } 170 171 static unsigned long read_pointer(const u8 **pLoc, 172 const void *end, signed ptrType); 173 174 static void init_unwind_table(struct unwind_table *table, const char *name, 175 const void *core_start, unsigned long core_size, 176 const void *init_start, unsigned long init_size, 177 const void *table_start, unsigned long table_size, 178 const u8 *header_start, unsigned long header_size) 179 { 180 const u8 *ptr = header_start + 4; 181 const u8 *end = header_start + header_size; 182 183 table->core.pc = (unsigned long)core_start; 184 table->core.range = core_size; 185 table->init.pc = (unsigned long)init_start; 186 table->init.range = init_size; 187 table->address = table_start; 188 table->size = table_size; 189 190 /* See if the linker provided table looks valid. */ 191 if (header_size <= 4 192 || header_start[0] != 1 193 || (void *)read_pointer(&ptr, end, header_start[1]) != table_start 194 || header_start[2] == DW_EH_PE_omit 195 || read_pointer(&ptr, end, header_start[2]) <= 0 196 || header_start[3] == DW_EH_PE_omit) 197 header_start = NULL; 198 199 table->hdrsz = header_size; 200 smp_wmb(); 201 table->header = header_start; 202 table->link = NULL; 203 table->name = name; 204 } 205 206 void __init arc_unwind_init(void) 207 { 208 init_unwind_table(&root_table, "kernel", _text, _end - _text, NULL, 0, 209 __start_unwind, __end_unwind - __start_unwind, 210 NULL, 0); 211 /*__start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr);*/ 212 } 213 214 static const u32 bad_cie, not_fde; 215 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *); 216 static signed fde_pointer_type(const u32 *cie); 217 218 struct eh_frame_hdr_table_entry { 219 unsigned long start, fde; 220 }; 221 222 static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2) 223 { 224 const struct eh_frame_hdr_table_entry *e1 = p1; 225 const struct eh_frame_hdr_table_entry *e2 = p2; 226 227 return (e1->start > e2->start) - (e1->start < e2->start); 228 } 229 230 static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size) 231 { 232 struct eh_frame_hdr_table_entry *e1 = p1; 233 struct eh_frame_hdr_table_entry *e2 = p2; 234 unsigned long v; 235 236 v = e1->start; 237 e1->start = e2->start; 238 e2->start = v; 239 v = e1->fde; 240 e1->fde = e2->fde; 241 e2->fde = v; 242 } 243 244 static void __init setup_unwind_table(struct unwind_table *table, 245 void *(*alloc) (unsigned long)) 246 { 247 const u8 *ptr; 248 unsigned long tableSize = table->size, hdrSize; 249 unsigned n; 250 const u32 *fde; 251 struct { 252 u8 version; 253 u8 eh_frame_ptr_enc; 254 u8 fde_count_enc; 255 u8 table_enc; 256 unsigned long eh_frame_ptr; 257 unsigned int fde_count; 258 struct eh_frame_hdr_table_entry table[]; 259 } __attribute__ ((__packed__)) *header; 260 261 if (table->header) 262 return; 263 264 if (table->hdrsz) 265 pr_warn(".eh_frame_hdr for '%s' present but unusable\n", 266 table->name); 267 268 if (tableSize & (sizeof(*fde) - 1)) 269 return; 270 271 for (fde = table->address, n = 0; 272 tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde; 273 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { 274 const u32 *cie = cie_for_fde(fde, table); 275 signed ptrType; 276 277 if (cie == ¬_fde) 278 continue; 279 if (cie == NULL || cie == &bad_cie) 280 return; 281 ptrType = fde_pointer_type(cie); 282 if (ptrType < 0) 283 return; 284 285 ptr = (const u8 *)(fde + 2); 286 if (!read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, 287 ptrType)) { 288 /* FIXME_Rajesh We have 4 instances of null addresses 289 * instead of the initial loc addr 290 * return; 291 */ 292 WARN(1, "unwinder: FDE->initial_location NULL %p\n", 293 (const u8 *)(fde + 1) + *fde); 294 } 295 ++n; 296 } 297 298 if (tableSize || !n) 299 return; 300 301 hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int) 302 + 2 * n * sizeof(unsigned long); 303 header = alloc(hdrSize); 304 if (!header) 305 return; 306 header->version = 1; 307 header->eh_frame_ptr_enc = DW_EH_PE_abs | DW_EH_PE_native; 308 header->fde_count_enc = DW_EH_PE_abs | DW_EH_PE_data4; 309 header->table_enc = DW_EH_PE_abs | DW_EH_PE_native; 310 put_unaligned((unsigned long)table->address, &header->eh_frame_ptr); 311 BUILD_BUG_ON(offsetof(typeof(*header), fde_count) 312 % __alignof(typeof(header->fde_count))); 313 header->fde_count = n; 314 315 BUILD_BUG_ON(offsetof(typeof(*header), table) 316 % __alignof(typeof(*header->table))); 317 for (fde = table->address, tableSize = table->size, n = 0; 318 tableSize; 319 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { 320 /* const u32 *cie = fde + 1 - fde[1] / sizeof(*fde); */ 321 const u32 *cie = (const u32 *)(fde[1]); 322 323 if (fde[1] == 0xffffffff) 324 continue; /* this is a CIE */ 325 ptr = (const u8 *)(fde + 2); 326 header->table[n].start = read_pointer(&ptr, 327 (const u8 *)(fde + 1) + 328 *fde, 329 fde_pointer_type(cie)); 330 header->table[n].fde = (unsigned long)fde; 331 ++n; 332 } 333 WARN_ON(n != header->fde_count); 334 335 sort(header->table, 336 n, 337 sizeof(*header->table), 338 cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries); 339 340 table->hdrsz = hdrSize; 341 smp_wmb(); 342 table->header = (const void *)header; 343 } 344 345 static void *__init balloc(unsigned long sz) 346 { 347 return __alloc_bootmem_nopanic(sz, 348 sizeof(unsigned int), 349 __pa(MAX_DMA_ADDRESS)); 350 } 351 352 void __init arc_unwind_setup(void) 353 { 354 setup_unwind_table(&root_table, balloc); 355 } 356 357 #ifdef CONFIG_MODULES 358 359 static struct unwind_table *last_table; 360 361 /* Must be called with module_mutex held. */ 362 void *unwind_add_table(struct module *module, const void *table_start, 363 unsigned long table_size) 364 { 365 struct unwind_table *table; 366 367 if (table_size <= 0) 368 return NULL; 369 370 table = kmalloc(sizeof(*table), GFP_KERNEL); 371 if (!table) 372 return NULL; 373 374 init_unwind_table(table, module->name, 375 module->module_core, module->core_size, 376 module->module_init, module->init_size, 377 table_start, table_size, 378 NULL, 0); 379 380 #ifdef UNWIND_DEBUG 381 unw_debug("Table added for [%s] %lx %lx\n", 382 module->name, table->core.pc, table->core.range); 383 #endif 384 if (last_table) 385 last_table->link = table; 386 else 387 root_table.link = table; 388 last_table = table; 389 390 return table; 391 } 392 393 struct unlink_table_info { 394 struct unwind_table *table; 395 int init_only; 396 }; 397 398 static int unlink_table(void *arg) 399 { 400 struct unlink_table_info *info = arg; 401 struct unwind_table *table = info->table, *prev; 402 403 for (prev = &root_table; prev->link && prev->link != table; 404 prev = prev->link) 405 ; 406 407 if (prev->link) { 408 if (info->init_only) { 409 table->init.pc = 0; 410 table->init.range = 0; 411 info->table = NULL; 412 } else { 413 prev->link = table->link; 414 if (!prev->link) 415 last_table = prev; 416 } 417 } else 418 info->table = NULL; 419 420 return 0; 421 } 422 423 /* Must be called with module_mutex held. */ 424 void unwind_remove_table(void *handle, int init_only) 425 { 426 struct unwind_table *table = handle; 427 struct unlink_table_info info; 428 429 if (!table || table == &root_table) 430 return; 431 432 if (init_only && table == last_table) { 433 table->init.pc = 0; 434 table->init.range = 0; 435 return; 436 } 437 438 info.table = table; 439 info.init_only = init_only; 440 441 unlink_table(&info); /* XXX: SMP */ 442 kfree(table); 443 } 444 445 #endif /* CONFIG_MODULES */ 446 447 static uleb128_t get_uleb128(const u8 **pcur, const u8 *end) 448 { 449 const u8 *cur = *pcur; 450 uleb128_t value; 451 unsigned shift; 452 453 for (shift = 0, value = 0; cur < end; shift += 7) { 454 if (shift + 7 > 8 * sizeof(value) 455 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) { 456 cur = end + 1; 457 break; 458 } 459 value |= (uleb128_t) (*cur & 0x7f) << shift; 460 if (!(*cur++ & 0x80)) 461 break; 462 } 463 *pcur = cur; 464 465 return value; 466 } 467 468 static sleb128_t get_sleb128(const u8 **pcur, const u8 *end) 469 { 470 const u8 *cur = *pcur; 471 sleb128_t value; 472 unsigned shift; 473 474 for (shift = 0, value = 0; cur < end; shift += 7) { 475 if (shift + 7 > 8 * sizeof(value) 476 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) { 477 cur = end + 1; 478 break; 479 } 480 value |= (sleb128_t) (*cur & 0x7f) << shift; 481 if (!(*cur & 0x80)) { 482 value |= -(*cur++ & 0x40) << shift; 483 break; 484 } 485 } 486 *pcur = cur; 487 488 return value; 489 } 490 491 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table) 492 { 493 const u32 *cie; 494 495 if (!*fde || (*fde & (sizeof(*fde) - 1))) 496 return &bad_cie; 497 498 if (fde[1] == 0xffffffff) 499 return ¬_fde; /* this is a CIE */ 500 501 if ((fde[1] & (sizeof(*fde) - 1))) 502 /* || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address) */ 503 return NULL; /* this is not a valid FDE */ 504 505 /* cie = fde + 1 - fde[1] / sizeof(*fde); */ 506 cie = (u32 *) fde[1]; 507 508 if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde) 509 || (*cie & (sizeof(*cie) - 1)) 510 || (cie[1] != 0xffffffff)) 511 return NULL; /* this is not a (valid) CIE */ 512 return cie; 513 } 514 515 static unsigned long read_pointer(const u8 **pLoc, const void *end, 516 signed ptrType) 517 { 518 unsigned long value = 0; 519 union { 520 const u8 *p8; 521 const u16 *p16u; 522 const s16 *p16s; 523 const u32 *p32u; 524 const s32 *p32s; 525 const unsigned long *pul; 526 } ptr; 527 528 if (ptrType < 0 || ptrType == DW_EH_PE_omit) 529 return 0; 530 ptr.p8 = *pLoc; 531 switch (ptrType & DW_EH_PE_FORM) { 532 case DW_EH_PE_data2: 533 if (end < (const void *)(ptr.p16u + 1)) 534 return 0; 535 if (ptrType & DW_EH_PE_signed) 536 value = get_unaligned((u16 *) ptr.p16s++); 537 else 538 value = get_unaligned((u16 *) ptr.p16u++); 539 break; 540 case DW_EH_PE_data4: 541 #ifdef CONFIG_64BIT 542 if (end < (const void *)(ptr.p32u + 1)) 543 return 0; 544 if (ptrType & DW_EH_PE_signed) 545 value = get_unaligned(ptr.p32s++); 546 else 547 value = get_unaligned(ptr.p32u++); 548 break; 549 case DW_EH_PE_data8: 550 BUILD_BUG_ON(sizeof(u64) != sizeof(value)); 551 #else 552 BUILD_BUG_ON(sizeof(u32) != sizeof(value)); 553 #endif 554 case DW_EH_PE_native: 555 if (end < (const void *)(ptr.pul + 1)) 556 return 0; 557 value = get_unaligned((unsigned long *)ptr.pul++); 558 break; 559 case DW_EH_PE_leb128: 560 BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value)); 561 value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end) 562 : get_uleb128(&ptr.p8, end); 563 if ((const void *)ptr.p8 > end) 564 return 0; 565 break; 566 default: 567 return 0; 568 } 569 switch (ptrType & DW_EH_PE_ADJUST) { 570 case DW_EH_PE_abs: 571 break; 572 case DW_EH_PE_pcrel: 573 value += (unsigned long)*pLoc; 574 break; 575 default: 576 return 0; 577 } 578 if ((ptrType & DW_EH_PE_indirect) 579 && __get_user(value, (unsigned long __user *)value)) 580 return 0; 581 *pLoc = ptr.p8; 582 583 return value; 584 } 585 586 static signed fde_pointer_type(const u32 *cie) 587 { 588 const u8 *ptr = (const u8 *)(cie + 2); 589 unsigned version = *ptr; 590 591 if (version != 1) 592 return -1; /* unsupported */ 593 594 if (*++ptr) { 595 const char *aug; 596 const u8 *end = (const u8 *)(cie + 1) + *cie; 597 uleb128_t len; 598 599 /* check if augmentation size is first (and thus present) */ 600 if (*ptr != 'z') 601 return -1; 602 603 /* check if augmentation string is nul-terminated */ 604 aug = (const void *)ptr; 605 ptr = memchr(aug, 0, end - ptr); 606 if (ptr == NULL) 607 return -1; 608 609 ++ptr; /* skip terminator */ 610 get_uleb128(&ptr, end); /* skip code alignment */ 611 get_sleb128(&ptr, end); /* skip data alignment */ 612 /* skip return address column */ 613 version <= 1 ? (void) ++ptr : (void)get_uleb128(&ptr, end); 614 len = get_uleb128(&ptr, end); /* augmentation length */ 615 616 if (ptr + len < ptr || ptr + len > end) 617 return -1; 618 619 end = ptr + len; 620 while (*++aug) { 621 if (ptr >= end) 622 return -1; 623 switch (*aug) { 624 case 'L': 625 ++ptr; 626 break; 627 case 'P':{ 628 signed ptrType = *ptr++; 629 630 if (!read_pointer(&ptr, end, ptrType) 631 || ptr > end) 632 return -1; 633 } 634 break; 635 case 'R': 636 return *ptr; 637 default: 638 return -1; 639 } 640 } 641 } 642 return DW_EH_PE_native | DW_EH_PE_abs; 643 } 644 645 static int advance_loc(unsigned long delta, struct unwind_state *state) 646 { 647 state->loc += delta * state->codeAlign; 648 649 /* FIXME_Rajesh: Probably we are defining for the initial range as well; 650 return delta > 0; 651 */ 652 unw_debug("delta %3lu => loc 0x%lx: ", delta, state->loc); 653 return 1; 654 } 655 656 static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value, 657 struct unwind_state *state) 658 { 659 if (reg < ARRAY_SIZE(state->regs)) { 660 state->regs[reg].where = where; 661 state->regs[reg].value = value; 662 663 #ifdef UNWIND_DEBUG 664 unw_debug("r%lu: ", reg); 665 switch (where) { 666 case Nowhere: 667 unw_debug("s "); 668 break; 669 case Memory: 670 unw_debug("c(%lu) ", value); 671 break; 672 case Register: 673 unw_debug("r(%lu) ", value); 674 break; 675 case Value: 676 unw_debug("v(%lu) ", value); 677 break; 678 default: 679 break; 680 } 681 #endif 682 } 683 } 684 685 static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc, 686 signed ptrType, struct unwind_state *state) 687 { 688 union { 689 const u8 *p8; 690 const u16 *p16; 691 const u32 *p32; 692 } ptr; 693 int result = 1; 694 u8 opcode; 695 696 if (start != state->cieStart) { 697 state->loc = state->org; 698 result = 699 processCFI(state->cieStart, state->cieEnd, 0, ptrType, 700 state); 701 if (targetLoc == 0 && state->label == NULL) 702 return result; 703 } 704 for (ptr.p8 = start; result && ptr.p8 < end;) { 705 switch (*ptr.p8 >> 6) { 706 uleb128_t value; 707 708 case 0: 709 opcode = *ptr.p8++; 710 711 switch (opcode) { 712 case DW_CFA_nop: 713 unw_debug("cfa nop "); 714 break; 715 case DW_CFA_set_loc: 716 state->loc = read_pointer(&ptr.p8, end, 717 ptrType); 718 if (state->loc == 0) 719 result = 0; 720 unw_debug("cfa_set_loc: 0x%lx ", state->loc); 721 break; 722 case DW_CFA_advance_loc1: 723 unw_debug("\ncfa advance loc1:"); 724 result = ptr.p8 < end 725 && advance_loc(*ptr.p8++, state); 726 break; 727 case DW_CFA_advance_loc2: 728 value = *ptr.p8++; 729 value += *ptr.p8++ << 8; 730 unw_debug("\ncfa advance loc2:"); 731 result = ptr.p8 <= end + 2 732 /* && advance_loc(*ptr.p16++, state); */ 733 && advance_loc(value, state); 734 break; 735 case DW_CFA_advance_loc4: 736 unw_debug("\ncfa advance loc4:"); 737 result = ptr.p8 <= end + 4 738 && advance_loc(*ptr.p32++, state); 739 break; 740 case DW_CFA_offset_extended: 741 value = get_uleb128(&ptr.p8, end); 742 unw_debug("cfa_offset_extended: "); 743 set_rule(value, Memory, 744 get_uleb128(&ptr.p8, end), state); 745 break; 746 case DW_CFA_val_offset: 747 value = get_uleb128(&ptr.p8, end); 748 set_rule(value, Value, 749 get_uleb128(&ptr.p8, end), state); 750 break; 751 case DW_CFA_offset_extended_sf: 752 value = get_uleb128(&ptr.p8, end); 753 set_rule(value, Memory, 754 get_sleb128(&ptr.p8, end), state); 755 break; 756 case DW_CFA_val_offset_sf: 757 value = get_uleb128(&ptr.p8, end); 758 set_rule(value, Value, 759 get_sleb128(&ptr.p8, end), state); 760 break; 761 case DW_CFA_restore_extended: 762 unw_debug("cfa_restore_extended: "); 763 case DW_CFA_undefined: 764 unw_debug("cfa_undefined: "); 765 case DW_CFA_same_value: 766 unw_debug("cfa_same_value: "); 767 set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0, 768 state); 769 break; 770 case DW_CFA_register: 771 unw_debug("cfa_register: "); 772 value = get_uleb128(&ptr.p8, end); 773 set_rule(value, 774 Register, 775 get_uleb128(&ptr.p8, end), state); 776 break; 777 case DW_CFA_remember_state: 778 unw_debug("cfa_remember_state: "); 779 if (ptr.p8 == state->label) { 780 state->label = NULL; 781 return 1; 782 } 783 if (state->stackDepth >= MAX_STACK_DEPTH) 784 return 0; 785 state->stack[state->stackDepth++] = ptr.p8; 786 break; 787 case DW_CFA_restore_state: 788 unw_debug("cfa_restore_state: "); 789 if (state->stackDepth) { 790 const uleb128_t loc = state->loc; 791 const u8 *label = state->label; 792 793 state->label = 794 state->stack[state->stackDepth - 1]; 795 memcpy(&state->cfa, &badCFA, 796 sizeof(state->cfa)); 797 memset(state->regs, 0, 798 sizeof(state->regs)); 799 state->stackDepth = 0; 800 result = 801 processCFI(start, end, 0, ptrType, 802 state); 803 state->loc = loc; 804 state->label = label; 805 } else 806 return 0; 807 break; 808 case DW_CFA_def_cfa: 809 state->cfa.reg = get_uleb128(&ptr.p8, end); 810 unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg); 811 /*nobreak*/ 812 case DW_CFA_def_cfa_offset: 813 state->cfa.offs = get_uleb128(&ptr.p8, end); 814 unw_debug("cfa_def_cfa_offset: 0x%lx ", 815 state->cfa.offs); 816 break; 817 case DW_CFA_def_cfa_sf: 818 state->cfa.reg = get_uleb128(&ptr.p8, end); 819 /*nobreak */ 820 case DW_CFA_def_cfa_offset_sf: 821 state->cfa.offs = get_sleb128(&ptr.p8, end) 822 * state->dataAlign; 823 break; 824 case DW_CFA_def_cfa_register: 825 unw_debug("cfa_def_cfa_regsiter: "); 826 state->cfa.reg = get_uleb128(&ptr.p8, end); 827 break; 828 /*todo case DW_CFA_def_cfa_expression: */ 829 /*todo case DW_CFA_expression: */ 830 /*todo case DW_CFA_val_expression: */ 831 case DW_CFA_GNU_args_size: 832 get_uleb128(&ptr.p8, end); 833 break; 834 case DW_CFA_GNU_negative_offset_extended: 835 value = get_uleb128(&ptr.p8, end); 836 set_rule(value, 837 Memory, 838 (uleb128_t) 0 - get_uleb128(&ptr.p8, 839 end), 840 state); 841 break; 842 case DW_CFA_GNU_window_save: 843 default: 844 unw_debug("UNKNOW OPCODE 0x%x\n", opcode); 845 result = 0; 846 break; 847 } 848 break; 849 case 1: 850 unw_debug("\ncfa_adv_loc: "); 851 result = advance_loc(*ptr.p8++ & 0x3f, state); 852 break; 853 case 2: 854 unw_debug("cfa_offset: "); 855 value = *ptr.p8++ & 0x3f; 856 set_rule(value, Memory, get_uleb128(&ptr.p8, end), 857 state); 858 break; 859 case 3: 860 unw_debug("cfa_restore: "); 861 set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state); 862 break; 863 } 864 865 if (ptr.p8 > end) 866 result = 0; 867 if (result && targetLoc != 0 && targetLoc < state->loc) 868 return 1; 869 } 870 871 return result && ptr.p8 == end && (targetLoc == 0 || ( 872 /*todo While in theory this should apply, gcc in practice omits 873 everything past the function prolog, and hence the location 874 never reaches the end of the function. 875 targetLoc < state->loc && */ state->label == NULL)); 876 } 877 878 /* Unwind to previous to frame. Returns 0 if successful, negative 879 * number in case of an error. */ 880 int arc_unwind(struct unwind_frame_info *frame) 881 { 882 #define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs]) 883 const u32 *fde = NULL, *cie = NULL; 884 const u8 *ptr = NULL, *end = NULL; 885 unsigned long pc = UNW_PC(frame) - frame->call_frame; 886 unsigned long startLoc = 0, endLoc = 0, cfa; 887 unsigned i; 888 signed ptrType = -1; 889 uleb128_t retAddrReg = 0; 890 const struct unwind_table *table; 891 struct unwind_state state; 892 unsigned long *fptr; 893 unsigned long addr; 894 895 unw_debug("\n\nUNWIND FRAME:\n"); 896 unw_debug("PC: 0x%lx BLINK: 0x%lx, SP: 0x%lx, FP: 0x%x\n", 897 UNW_PC(frame), UNW_BLINK(frame), UNW_SP(frame), 898 UNW_FP(frame)); 899 900 if (UNW_PC(frame) == 0) 901 return -EINVAL; 902 903 #ifdef UNWIND_DEBUG 904 { 905 unsigned long *sptr = (unsigned long *)UNW_SP(frame); 906 unw_debug("\nStack Dump:\n"); 907 for (i = 0; i < 20; i++, sptr++) 908 unw_debug("0x%p: 0x%lx\n", sptr, *sptr); 909 unw_debug("\n"); 910 } 911 #endif 912 913 table = find_table(pc); 914 if (table != NULL 915 && !(table->size & (sizeof(*fde) - 1))) { 916 const u8 *hdr = table->header; 917 unsigned long tableSize; 918 919 smp_rmb(); 920 if (hdr && hdr[0] == 1) { 921 switch (hdr[3] & DW_EH_PE_FORM) { 922 case DW_EH_PE_native: 923 tableSize = sizeof(unsigned long); 924 break; 925 case DW_EH_PE_data2: 926 tableSize = 2; 927 break; 928 case DW_EH_PE_data4: 929 tableSize = 4; 930 break; 931 case DW_EH_PE_data8: 932 tableSize = 8; 933 break; 934 default: 935 tableSize = 0; 936 break; 937 } 938 ptr = hdr + 4; 939 end = hdr + table->hdrsz; 940 if (tableSize && read_pointer(&ptr, end, hdr[1]) 941 == (unsigned long)table->address 942 && (i = read_pointer(&ptr, end, hdr[2])) > 0 943 && i == (end - ptr) / (2 * tableSize) 944 && !((end - ptr) % (2 * tableSize))) { 945 do { 946 const u8 *cur = 947 ptr + (i / 2) * (2 * tableSize); 948 949 startLoc = read_pointer(&cur, 950 cur + tableSize, 951 hdr[3]); 952 if (pc < startLoc) 953 i /= 2; 954 else { 955 ptr = cur - tableSize; 956 i = (i + 1) / 2; 957 } 958 } while (startLoc && i > 1); 959 if (i == 1 960 && (startLoc = read_pointer(&ptr, 961 ptr + tableSize, 962 hdr[3])) != 0 963 && pc >= startLoc) 964 fde = (void *)read_pointer(&ptr, 965 ptr + 966 tableSize, 967 hdr[3]); 968 } 969 } 970 971 if (fde != NULL) { 972 cie = cie_for_fde(fde, table); 973 ptr = (const u8 *)(fde + 2); 974 if (cie != NULL 975 && cie != &bad_cie 976 && cie != ¬_fde 977 && (ptrType = fde_pointer_type(cie)) >= 0 978 && read_pointer(&ptr, 979 (const u8 *)(fde + 1) + *fde, 980 ptrType) == startLoc) { 981 if (!(ptrType & DW_EH_PE_indirect)) 982 ptrType &= 983 DW_EH_PE_FORM | DW_EH_PE_signed; 984 endLoc = 985 startLoc + read_pointer(&ptr, 986 (const u8 *)(fde + 987 1) + 988 *fde, ptrType); 989 if (pc >= endLoc) 990 fde = NULL; 991 } else 992 fde = NULL; 993 } 994 if (fde == NULL) { 995 for (fde = table->address, tableSize = table->size; 996 cie = NULL, tableSize > sizeof(*fde) 997 && tableSize - sizeof(*fde) >= *fde; 998 tableSize -= sizeof(*fde) + *fde, 999 fde += 1 + *fde / sizeof(*fde)) { 1000 cie = cie_for_fde(fde, table); 1001 if (cie == &bad_cie) { 1002 cie = NULL; 1003 break; 1004 } 1005 if (cie == NULL 1006 || cie == ¬_fde 1007 || (ptrType = fde_pointer_type(cie)) < 0) 1008 continue; 1009 ptr = (const u8 *)(fde + 2); 1010 startLoc = read_pointer(&ptr, 1011 (const u8 *)(fde + 1) + 1012 *fde, ptrType); 1013 if (!startLoc) 1014 continue; 1015 if (!(ptrType & DW_EH_PE_indirect)) 1016 ptrType &= 1017 DW_EH_PE_FORM | DW_EH_PE_signed; 1018 endLoc = 1019 startLoc + read_pointer(&ptr, 1020 (const u8 *)(fde + 1021 1) + 1022 *fde, ptrType); 1023 if (pc >= startLoc && pc < endLoc) 1024 break; 1025 } 1026 } 1027 } 1028 if (cie != NULL) { 1029 memset(&state, 0, sizeof(state)); 1030 state.cieEnd = ptr; /* keep here temporarily */ 1031 ptr = (const u8 *)(cie + 2); 1032 end = (const u8 *)(cie + 1) + *cie; 1033 frame->call_frame = 1; 1034 if ((state.version = *ptr) != 1) 1035 cie = NULL; /* unsupported version */ 1036 else if (*++ptr) { 1037 /* check if augmentation size is first (thus present) */ 1038 if (*ptr == 'z') { 1039 while (++ptr < end && *ptr) { 1040 switch (*ptr) { 1041 /* chk for ignorable or already handled 1042 * nul-terminated augmentation string */ 1043 case 'L': 1044 case 'P': 1045 case 'R': 1046 continue; 1047 case 'S': 1048 frame->call_frame = 0; 1049 continue; 1050 default: 1051 break; 1052 } 1053 break; 1054 } 1055 } 1056 if (ptr >= end || *ptr) 1057 cie = NULL; 1058 } 1059 ++ptr; 1060 } 1061 if (cie != NULL) { 1062 /* get code aligment factor */ 1063 state.codeAlign = get_uleb128(&ptr, end); 1064 /* get data aligment factor */ 1065 state.dataAlign = get_sleb128(&ptr, end); 1066 if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end) 1067 cie = NULL; 1068 else { 1069 retAddrReg = 1070 state.version <= 1 ? *ptr++ : get_uleb128(&ptr, 1071 end); 1072 unw_debug("CIE Frame Info:\n"); 1073 unw_debug("return Address register 0x%lx\n", 1074 retAddrReg); 1075 unw_debug("data Align: %ld\n", state.dataAlign); 1076 unw_debug("code Align: %lu\n", state.codeAlign); 1077 /* skip augmentation */ 1078 if (((const char *)(cie + 2))[1] == 'z') { 1079 uleb128_t augSize = get_uleb128(&ptr, end); 1080 1081 ptr += augSize; 1082 } 1083 if (ptr > end || retAddrReg >= ARRAY_SIZE(reg_info) 1084 || REG_INVALID(retAddrReg) 1085 || reg_info[retAddrReg].width != 1086 sizeof(unsigned long)) 1087 cie = NULL; 1088 } 1089 } 1090 if (cie != NULL) { 1091 state.cieStart = ptr; 1092 ptr = state.cieEnd; 1093 state.cieEnd = end; 1094 end = (const u8 *)(fde + 1) + *fde; 1095 /* skip augmentation */ 1096 if (((const char *)(cie + 2))[1] == 'z') { 1097 uleb128_t augSize = get_uleb128(&ptr, end); 1098 1099 if ((ptr += augSize) > end) 1100 fde = NULL; 1101 } 1102 } 1103 if (cie == NULL || fde == NULL) { 1104 #ifdef CONFIG_FRAME_POINTER 1105 unsigned long top, bottom; 1106 1107 top = STACK_TOP_UNW(frame->task); 1108 bottom = STACK_BOTTOM_UNW(frame->task); 1109 #if FRAME_RETADDR_OFFSET < 0 1110 if (UNW_SP(frame) < top && UNW_FP(frame) <= UNW_SP(frame) 1111 && bottom < UNW_FP(frame) 1112 #else 1113 if (UNW_SP(frame) > top && UNW_FP(frame) >= UNW_SP(frame) 1114 && bottom > UNW_FP(frame) 1115 #endif 1116 && !((UNW_SP(frame) | UNW_FP(frame)) 1117 & (sizeof(unsigned long) - 1))) { 1118 unsigned long link; 1119 1120 if (!__get_user(link, (unsigned long *) 1121 (UNW_FP(frame) + FRAME_LINK_OFFSET)) 1122 #if FRAME_RETADDR_OFFSET < 0 1123 && link > bottom && link < UNW_FP(frame) 1124 #else 1125 && link > UNW_FP(frame) && link < bottom 1126 #endif 1127 && !(link & (sizeof(link) - 1)) 1128 && !__get_user(UNW_PC(frame), 1129 (unsigned long *)(UNW_FP(frame) 1130 + FRAME_RETADDR_OFFSET))) 1131 { 1132 UNW_SP(frame) = 1133 UNW_FP(frame) + FRAME_RETADDR_OFFSET 1134 #if FRAME_RETADDR_OFFSET < 0 1135 - 1136 #else 1137 + 1138 #endif 1139 sizeof(UNW_PC(frame)); 1140 UNW_FP(frame) = link; 1141 return 0; 1142 } 1143 } 1144 #endif 1145 return -ENXIO; 1146 } 1147 state.org = startLoc; 1148 memcpy(&state.cfa, &badCFA, sizeof(state.cfa)); 1149 1150 unw_debug("\nProcess instructions\n"); 1151 1152 /* process instructions 1153 * For ARC, we optimize by having blink(retAddrReg) with 1154 * the sameValue in the leaf function, so we should not check 1155 * state.regs[retAddrReg].where == Nowhere 1156 */ 1157 if (!processCFI(ptr, end, pc, ptrType, &state) 1158 || state.loc > endLoc 1159 /* || state.regs[retAddrReg].where == Nowhere */ 1160 || state.cfa.reg >= ARRAY_SIZE(reg_info) 1161 || reg_info[state.cfa.reg].width != sizeof(unsigned long) 1162 || state.cfa.offs % sizeof(unsigned long)) 1163 return -EIO; 1164 1165 #ifdef UNWIND_DEBUG 1166 unw_debug("\n"); 1167 1168 unw_debug("\nRegister State Based on the rules parsed from FDE:\n"); 1169 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) { 1170 1171 if (REG_INVALID(i)) 1172 continue; 1173 1174 switch (state.regs[i].where) { 1175 case Nowhere: 1176 break; 1177 case Memory: 1178 unw_debug(" r%d: c(%lu),", i, state.regs[i].value); 1179 break; 1180 case Register: 1181 unw_debug(" r%d: r(%lu),", i, state.regs[i].value); 1182 break; 1183 case Value: 1184 unw_debug(" r%d: v(%lu),", i, state.regs[i].value); 1185 break; 1186 } 1187 } 1188 1189 unw_debug("\n"); 1190 #endif 1191 1192 /* update frame */ 1193 #ifndef CONFIG_AS_CFI_SIGNAL_FRAME 1194 if (frame->call_frame 1195 && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign)) 1196 frame->call_frame = 0; 1197 #endif 1198 cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs; 1199 startLoc = min_t(unsigned long, UNW_SP(frame), cfa); 1200 endLoc = max_t(unsigned long, UNW_SP(frame), cfa); 1201 if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) { 1202 startLoc = min(STACK_LIMIT(cfa), cfa); 1203 endLoc = max(STACK_LIMIT(cfa), cfa); 1204 } 1205 1206 unw_debug("\nCFA reg: 0x%lx, offset: 0x%lx => 0x%lx\n", 1207 state.cfa.reg, state.cfa.offs, cfa); 1208 1209 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) { 1210 if (REG_INVALID(i)) { 1211 if (state.regs[i].where == Nowhere) 1212 continue; 1213 return -EIO; 1214 } 1215 switch (state.regs[i].where) { 1216 default: 1217 break; 1218 case Register: 1219 if (state.regs[i].value >= ARRAY_SIZE(reg_info) 1220 || REG_INVALID(state.regs[i].value) 1221 || reg_info[i].width > 1222 reg_info[state.regs[i].value].width) 1223 return -EIO; 1224 switch (reg_info[state.regs[i].value].width) { 1225 case sizeof(u8): 1226 state.regs[i].value = 1227 FRAME_REG(state.regs[i].value, const u8); 1228 break; 1229 case sizeof(u16): 1230 state.regs[i].value = 1231 FRAME_REG(state.regs[i].value, const u16); 1232 break; 1233 case sizeof(u32): 1234 state.regs[i].value = 1235 FRAME_REG(state.regs[i].value, const u32); 1236 break; 1237 #ifdef CONFIG_64BIT 1238 case sizeof(u64): 1239 state.regs[i].value = 1240 FRAME_REG(state.regs[i].value, const u64); 1241 break; 1242 #endif 1243 default: 1244 return -EIO; 1245 } 1246 break; 1247 } 1248 } 1249 1250 unw_debug("\nRegister state after evaluation with realtime Stack:\n"); 1251 fptr = (unsigned long *)(&frame->regs); 1252 for (i = 0; i < ARRAY_SIZE(state.regs); ++i, fptr++) { 1253 1254 if (REG_INVALID(i)) 1255 continue; 1256 switch (state.regs[i].where) { 1257 case Nowhere: 1258 if (reg_info[i].width != sizeof(UNW_SP(frame)) 1259 || &FRAME_REG(i, __typeof__(UNW_SP(frame))) 1260 != &UNW_SP(frame)) 1261 continue; 1262 UNW_SP(frame) = cfa; 1263 break; 1264 case Register: 1265 switch (reg_info[i].width) { 1266 case sizeof(u8): 1267 FRAME_REG(i, u8) = state.regs[i].value; 1268 break; 1269 case sizeof(u16): 1270 FRAME_REG(i, u16) = state.regs[i].value; 1271 break; 1272 case sizeof(u32): 1273 FRAME_REG(i, u32) = state.regs[i].value; 1274 break; 1275 #ifdef CONFIG_64BIT 1276 case sizeof(u64): 1277 FRAME_REG(i, u64) = state.regs[i].value; 1278 break; 1279 #endif 1280 default: 1281 return -EIO; 1282 } 1283 break; 1284 case Value: 1285 if (reg_info[i].width != sizeof(unsigned long)) 1286 return -EIO; 1287 FRAME_REG(i, unsigned long) = cfa + state.regs[i].value 1288 * state.dataAlign; 1289 break; 1290 case Memory: 1291 addr = cfa + state.regs[i].value * state.dataAlign; 1292 1293 if ((state.regs[i].value * state.dataAlign) 1294 % sizeof(unsigned long) 1295 || addr < startLoc 1296 || addr + sizeof(unsigned long) < addr 1297 || addr + sizeof(unsigned long) > endLoc) 1298 return -EIO; 1299 1300 switch (reg_info[i].width) { 1301 case sizeof(u8): 1302 __get_user(FRAME_REG(i, u8), 1303 (u8 __user *)addr); 1304 break; 1305 case sizeof(u16): 1306 __get_user(FRAME_REG(i, u16), 1307 (u16 __user *)addr); 1308 break; 1309 case sizeof(u32): 1310 __get_user(FRAME_REG(i, u32), 1311 (u32 __user *)addr); 1312 break; 1313 #ifdef CONFIG_64BIT 1314 case sizeof(u64): 1315 __get_user(FRAME_REG(i, u64), 1316 (u64 __user *)addr); 1317 break; 1318 #endif 1319 default: 1320 return -EIO; 1321 } 1322 1323 break; 1324 } 1325 unw_debug("r%d: 0x%lx ", i, *fptr); 1326 } 1327 1328 return 0; 1329 #undef FRAME_REG 1330 } 1331 EXPORT_SYMBOL(arc_unwind); 1332