porting_aix.cpp revision 13200:54010cf75b26
1/* 2 * Copyright (c) 2012, 2013 SAP SE. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "asm/assembler.hpp" 26#include "compiler/disassembler.hpp" 27#include "loadlib_aix.hpp" 28#include "memory/allocation.hpp" 29#include "memory/allocation.inline.hpp" 30#include "misc_aix.hpp" 31#include "porting_aix.hpp" 32#include "runtime/os.hpp" 33#include "runtime/thread.hpp" 34#include "utilities/debug.hpp" 35 36#include <demangle.h> 37#include <sys/debug.h> 38#include <pthread.h> 39#include <ucontext.h> 40 41////////////////////////////////// 42// Provide implementation for dladdr based on LoadedLibraries pool and 43// traceback table scan 44 45// Search traceback table in stack, 46// return procedure name from trace back table. 47#define MAX_FUNC_SEARCH_LEN 0x10000 48 49#define PTRDIFF_BYTES(p1,p2) (((ptrdiff_t)p1) - ((ptrdiff_t)p2)) 50 51// Typedefs for stackslots, stack pointers, pointers to op codes. 52typedef unsigned long stackslot_t; 53typedef stackslot_t* stackptr_t; 54typedef unsigned int* codeptr_t; 55 56// Unfortunately, the interface of dladdr makes the implementator 57// responsible for maintaining memory for function name/library 58// name. I guess this is because most OS's keep those values as part 59// of the mapped executable image ready to use. On AIX, this doesn't 60// work, so I have to keep the returned strings. For now, I do this in 61// a primitive string map. Should this turn out to be a performance 62// problem, a better hashmap has to be used. 63class fixed_strings { 64 struct node : public CHeapObj<mtInternal> { 65 char* v; 66 node* next; 67 }; 68 69 node* first; 70 71 public: 72 73 fixed_strings() : first(0) {} 74 ~fixed_strings() { 75 node* n = first; 76 while (n) { 77 node* p = n; 78 n = n->next; 79 os::free(p->v); 80 delete p; 81 } 82 } 83 84 char* intern(const char* s) { 85 for (node* n = first; n; n = n->next) { 86 if (strcmp(n->v, s) == 0) { 87 return n->v; 88 } 89 } 90 node* p = new node; 91 p->v = os::strdup_check_oom(s); 92 p->next = first; 93 first = p; 94 return p->v; 95 } 96}; 97 98static fixed_strings dladdr_fixed_strings; 99 100bool AixSymbols::get_function_name ( 101 address pc0, // [in] program counter 102 char* p_name, size_t namelen, // [out] optional: function name ("" if not available) 103 int* p_displacement, // [out] optional: displacement (-1 if not available) 104 const struct tbtable** p_tb, // [out] optional: ptr to traceback table to get further 105 // information (NULL if not available) 106 bool demangle // [in] whether to demangle the name 107 ) { 108 struct tbtable* tb = 0; 109 unsigned int searchcount = 0; 110 111 // initialize output parameters 112 if (p_name && namelen > 0) { 113 *p_name = '\0'; 114 } 115 if (p_displacement) { 116 *p_displacement = -1; 117 } 118 if (p_tb) { 119 *p_tb = NULL; 120 } 121 122 codeptr_t pc = (codeptr_t)pc0; 123 124 // weed out obvious bogus states 125 if (pc < (codeptr_t)0x1000) { 126 trcVerbose("invalid program counter"); 127 return false; 128 } 129 130 // We see random but frequent crashes in this function since some months mainly on shutdown 131 // (-XX:+DumpInfoAtExit). It appears the page we are reading is randomly disappearing while 132 // we read it (?). 133 // As the pc cannot be trusted to be anything sensible lets make all reads via SafeFetch. Also 134 // bail if this is not a text address right now. 135 if (!LoadedLibraries::find_for_text_address(pc, NULL)) { 136 trcVerbose("not a text address"); 137 return false; 138 } 139 140 // .. (Note that is_readable_pointer returns true if safefetch stubs are not there yet; 141 // in that case I try reading the traceback table unsafe - I rather risk secondary crashes in 142 // error files than not having a callstack.) 143#define CHECK_POINTER_READABLE(p) \ 144 if (!MiscUtils::is_readable_pointer(p)) { \ 145 trcVerbose("pc not readable"); \ 146 return false; \ 147 } 148 149 codeptr_t pc2 = (codeptr_t) pc; 150 151 // Make sure the pointer is word aligned. 152 pc2 = (codeptr_t) align_ptr_up((char*)pc2, 4); 153 CHECK_POINTER_READABLE(pc2) 154 155 // Find start of traceback table. 156 // (starts after code, is marked by word-aligned (32bit) zeros) 157 while ((*pc2 != NULL) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) { 158 CHECK_POINTER_READABLE(pc2) 159 pc2++; 160 } 161 if (*pc2 != 0) { 162 trcVerbose("no traceback table found"); 163 return false; 164 } 165 // 166 // Set up addressability to the traceback table 167 // 168 tb = (struct tbtable*) (pc2 + 1); 169 170 // Is this really a traceback table? No way to be sure but 171 // some indicators we can check. 172 if (tb->tb.lang >= 0xf && tb->tb.lang <= 0xfb) { 173 // Language specifiers, go from 0 (C) to 14 (Objective C). 174 // According to spec, 0xf-0xfa reserved, 0xfb-0xff reserved for ibm. 175 trcVerbose("no traceback table found"); 176 return false; 177 } 178 179 // Existence of fields in the tbtable extension are contingent upon 180 // specific fields in the base table. Check for their existence so 181 // that we can address the function name if it exists. 182 pc2 = (codeptr_t) tb + 183 sizeof(struct tbtable_short)/sizeof(int); 184 if (tb->tb.fixedparms != 0 || tb->tb.floatparms != 0) 185 pc2++; 186 187 CHECK_POINTER_READABLE(pc2) 188 189 if (tb->tb.has_tboff == TRUE) { 190 191 // I want to know the displacement 192 const unsigned int tb_offset = *pc2; 193 codeptr_t start_of_procedure = 194 (codeptr_t)(((char*)tb) - 4 - tb_offset); // (-4 to omit leading 0000) 195 196 // Weed out the cases where we did find the wrong traceback table. 197 if (pc < start_of_procedure) { 198 trcVerbose("no traceback table found"); 199 return false; 200 } 201 202 // return the displacement 203 if (p_displacement) { 204 (*p_displacement) = (int) PTRDIFF_BYTES(pc, start_of_procedure); 205 } 206 207 pc2++; 208 } else { 209 // return -1 for displacement 210 if (p_displacement) { 211 (*p_displacement) = -1; 212 } 213 } 214 215 if (tb->tb.int_hndl == TRUE) 216 pc2++; 217 218 if (tb->tb.has_ctl == TRUE) 219 pc2 += (*pc2) + 1; // don't care 220 221 CHECK_POINTER_READABLE(pc2) 222 223 // 224 // return function name if it exists. 225 // 226 if (p_name && namelen > 0) { 227 if (tb->tb.name_present) { 228 // Copy name from text because it may not be zero terminated. 229 const short l = MIN2<short>(*((short*)pc2), namelen - 1); 230 // Be very careful. 231 int i = 0; char* const p = (char*)pc2 + sizeof(short); 232 while (i < l && MiscUtils::is_readable_pointer(p + i)) { 233 p_name[i] = p[i]; 234 i++; 235 } 236 p_name[i] = '\0'; 237 238 // If it is a C++ name, try and demangle it using the Demangle interface (see demangle.h). 239 if (demangle) { 240 char* rest; 241 Name* const name = Demangle(p_name, rest); 242 if (name) { 243 const char* const demangled_name = name->Text(); 244 if (demangled_name) { 245 strncpy(p_name, demangled_name, namelen-1); 246 p_name[namelen-1] = '\0'; 247 } 248 delete name; 249 } 250 } 251 } else { 252 strncpy(p_name, "<nameless function>", namelen-1); 253 p_name[namelen-1] = '\0'; 254 } 255 } 256 257 // Return traceback table, if user wants it. 258 if (p_tb) { 259 (*p_tb) = tb; 260 } 261 262 return true; 263 264} 265 266bool AixSymbols::get_module_name(address pc, 267 char* p_name, size_t namelen) { 268 269 if (p_name && namelen > 0) { 270 p_name[0] = '\0'; 271 loaded_module_t lm; 272 if (LoadedLibraries::find_for_text_address(pc, &lm) != NULL) { 273 strncpy(p_name, lm.shortname, namelen); 274 p_name[namelen - 1] = '\0'; 275 return true; 276 } 277 } 278 279 return false; 280} 281 282// Special implementation of dladdr for Aix based on LoadedLibraries 283// Note: dladdr returns non-zero for ok, 0 for error! 284// Note: dladdr is not posix, but a non-standard GNU extension. So this tries to 285// fulfill the contract of dladdr on Linux (see http://linux.die.net/man/3/dladdr) 286// Note: addr may be both an AIX function descriptor or a real code pointer 287// to the entry of a function. 288extern "C" 289int dladdr(void* addr, Dl_info* info) { 290 291 if (!addr) { 292 return 0; 293 } 294 295 assert(info, ""); 296 297 int rc = 0; 298 299 const char* const ZEROSTRING = ""; 300 301 // Always return a string, even if a "" one. Linux dladdr manpage 302 // does not say anything about returning NULL 303 info->dli_fname = ZEROSTRING; 304 info->dli_sname = ZEROSTRING; 305 info->dli_saddr = NULL; 306 307 address p = (address) addr; 308 loaded_module_t lm; 309 bool found = false; 310 311 enum { noclue, code, data } type = noclue; 312 313 trcVerbose("dladdr(%p)...", p); 314 315 // Note: input address may be a function. I accept both a pointer to 316 // the entry of a function and a pointer to the function decriptor. 317 // (see ppc64 ABI) 318 found = LoadedLibraries::find_for_text_address(p, &lm); 319 if (found) { 320 type = code; 321 } 322 323 if (!found) { 324 // Not a pointer into any text segment. Is it a function descriptor? 325 const FunctionDescriptor* const pfd = (const FunctionDescriptor*) p; 326 p = pfd->entry(); 327 if (p) { 328 found = LoadedLibraries::find_for_text_address(p, &lm); 329 if (found) { 330 type = code; 331 } 332 } 333 } 334 335 if (!found) { 336 // Neither direct code pointer nor function descriptor. A data ptr? 337 p = (address)addr; 338 found = LoadedLibraries::find_for_data_address(p, &lm); 339 if (found) { 340 type = data; 341 } 342 } 343 344 // If we did find the shared library this address belongs to (either 345 // code or data segment) resolve library path and, if possible, the 346 // symbol name. 347 if (found) { 348 349 // No need to intern the libpath, that one is already interned one layer below. 350 info->dli_fname = lm.path; 351 352 if (type == code) { 353 354 // For code symbols resolve function name and displacement. Use 355 // displacement to calc start of function. 356 char funcname[256] = ""; 357 int displacement = 0; 358 359 if (AixSymbols::get_function_name(p, funcname, sizeof(funcname), 360 &displacement, NULL, true)) { 361 if (funcname[0] != '\0') { 362 const char* const interned = dladdr_fixed_strings.intern(funcname); 363 info->dli_sname = interned; 364 trcVerbose("... function name: %s ...", interned); 365 } 366 367 // From the displacement calculate the start of the function. 368 if (displacement != -1) { 369 info->dli_saddr = p - displacement; 370 } else { 371 info->dli_saddr = p; 372 } 373 } else { 374 375 // No traceback table found. Just assume the pointer is it. 376 info->dli_saddr = p; 377 378 } 379 380 } else if (type == data) { 381 382 // For data symbols. 383 info->dli_saddr = p; 384 385 } else { 386 ShouldNotReachHere(); 387 } 388 389 rc = 1; // success: return 1 [sic] 390 391 } 392 393 // sanity checks. 394 if (rc) { 395 assert(info->dli_fname, ""); 396 assert(info->dli_sname, ""); 397 assert(info->dli_saddr, ""); 398 } 399 400 return rc; // error: return 0 [sic] 401 402} 403 404///////////////////////////////////////////////////////////////////////////// 405// Native callstack dumping 406 407// Print the traceback table for one stack frame. 408static void print_tbtable (outputStream* st, const struct tbtable* p_tb) { 409 410 if (p_tb == NULL) { 411 st->print("<null>"); 412 return; 413 } 414 415 switch(p_tb->tb.lang) { 416 case TB_C: st->print("C"); break; 417 case TB_FORTRAN: st->print("FORTRAN"); break; 418 case TB_PASCAL: st->print("PASCAL"); break; 419 case TB_ADA: st->print("ADA"); break; 420 case TB_PL1: st->print("PL1"); break; 421 case TB_BASIC: st->print("BASIC"); break; 422 case TB_LISP: st->print("LISP"); break; 423 case TB_COBOL: st->print("COBOL"); break; 424 case TB_MODULA2: st->print("MODULA2"); break; 425 case TB_CPLUSPLUS: st->print("C++"); break; 426 case TB_RPG: st->print("RPG"); break; 427 case TB_PL8: st->print("PL8"); break; 428 case TB_ASM: st->print("ASM"); break; 429 case TB_HPJ: st->print("HPJ"); break; 430 default: st->print("unknown"); 431 } 432 st->print(" "); 433 434 if (p_tb->tb.globallink) { 435 st->print("globallink "); 436 } 437 if (p_tb->tb.is_eprol) { 438 st->print("eprol "); 439 } 440 if (p_tb->tb.int_proc) { 441 st->print("int_proc "); 442 } 443 if (p_tb->tb.tocless) { 444 st->print("tocless "); 445 } 446 if (p_tb->tb.fp_present) { 447 st->print("fp_present "); 448 } 449 if (p_tb->tb.int_hndl) { 450 st->print("interrupt_handler "); 451 } 452 if (p_tb->tb.uses_alloca) { 453 st->print("uses_alloca "); 454 } 455 if (p_tb->tb.saves_cr) { 456 st->print("saves_cr "); 457 } 458 if (p_tb->tb.saves_lr) { 459 st->print("saves_lr "); 460 } 461 if (p_tb->tb.stores_bc) { 462 st->print("stores_bc "); 463 } 464 if (p_tb->tb.fixup) { 465 st->print("fixup "); 466 } 467 if (p_tb->tb.fpr_saved > 0) { 468 st->print("fpr_saved:%d ", p_tb->tb.fpr_saved); 469 } 470 if (p_tb->tb.gpr_saved > 0) { 471 st->print("gpr_saved:%d ", p_tb->tb.gpr_saved); 472 } 473 if (p_tb->tb.fixedparms > 0) { 474 st->print("fixedparms:%d ", p_tb->tb.fixedparms); 475 } 476 if (p_tb->tb.floatparms > 0) { 477 st->print("floatparms:%d ", p_tb->tb.floatparms); 478 } 479 if (p_tb->tb.parmsonstk > 0) { 480 st->print("parmsonstk:%d", p_tb->tb.parmsonstk); 481 } 482} 483 484// Print information for pc (module, function, displacement, traceback table) 485// on one line. 486static void print_info_for_pc (outputStream* st, codeptr_t pc, char* buf, 487 size_t buf_size, bool demangle) { 488 const struct tbtable* tb = NULL; 489 int displacement = -1; 490 491 if (!MiscUtils::is_readable_pointer(pc)) { 492 st->print("(invalid)"); 493 return; 494 } 495 496 if (AixSymbols::get_module_name((address)pc, buf, buf_size)) { 497 st->print("%s", buf); 498 } else { 499 st->print("(unknown module)"); 500 } 501 st->print("::"); 502 if (AixSymbols::get_function_name((address)pc, buf, buf_size, 503 &displacement, &tb, demangle)) { 504 st->print("%s", buf); 505 } else { 506 st->print("(unknown function)"); 507 } 508 if (displacement == -1) { 509 st->print("+?"); 510 } else { 511 st->print("+0x%x", displacement); 512 } 513 if (tb) { 514 st->fill_to(64); 515 st->print(" ("); 516 print_tbtable(st, tb); 517 st->print(")"); 518 } 519} 520 521static void print_stackframe(outputStream* st, stackptr_t sp, char* buf, 522 size_t buf_size, bool demangle) { 523 524 stackptr_t sp2 = sp; 525 526 // skip backchain 527 528 sp2++; 529 530 // skip crsave 531 532 sp2++; 533 534 // retrieve lrsave. That is the only info I need to get the function/displacement 535 536 codeptr_t lrsave = (codeptr_t) *(sp2); 537 st->print (PTR64_FORMAT " - " PTR64_FORMAT " ", sp2, lrsave); 538 539 if (lrsave != NULL) { 540 print_info_for_pc(st, lrsave, buf, buf_size, demangle); 541 } 542 543} 544 545// Function to check a given stack pointer against given stack limits. 546static bool is_valid_stackpointer(stackptr_t sp, stackptr_t stack_base, size_t stack_size) { 547 if (((uintptr_t)sp) & 0x7) { 548 return false; 549 } 550 if (sp > stack_base) { 551 return false; 552 } 553 if (sp < (stackptr_t) ((address)stack_base - stack_size)) { 554 return false; 555 } 556 return true; 557} 558 559// Returns true if function is a valid codepointer. 560static bool is_valid_codepointer(codeptr_t p) { 561 if (!p) { 562 return false; 563 } 564 if (((uintptr_t)p) & 0x3) { 565 return false; 566 } 567 if (LoadedLibraries::find_for_text_address(p, NULL) == NULL) { 568 return false; 569 } 570 return true; 571} 572 573// Function tries to guess if the given combination of stack pointer, stack base 574// and stack size is a valid stack frame. 575static bool is_valid_frame (stackptr_t p, stackptr_t stack_base, size_t stack_size) { 576 577 if (!is_valid_stackpointer(p, stack_base, stack_size)) { 578 return false; 579 } 580 581 // First check - the occurrence of a valid backchain pointer up the stack, followed by a 582 // valid codeptr, counts as a good candidate. 583 stackptr_t sp2 = (stackptr_t) *p; 584 if (is_valid_stackpointer(sp2, stack_base, stack_size) && // found a valid stack pointer in the stack... 585 ((sp2 - p) > 6) && // ... pointing upwards and not into my frame... 586 is_valid_codepointer((codeptr_t)(*(sp2 + 2)))) // ... followed by a code pointer after two slots... 587 { 588 return true; 589 } 590 591 return false; 592} 593 594// Try to relocate a stack back chain in a given stack. 595// Used in callstack dumping, when the backchain is broken by an overwriter 596static stackptr_t try_find_backchain (stackptr_t last_known_good_frame, 597 stackptr_t stack_base, size_t stack_size) 598{ 599 if (!is_valid_stackpointer(last_known_good_frame, stack_base, stack_size)) { 600 return NULL; 601 } 602 603 stackptr_t sp = last_known_good_frame; 604 605 sp += 6; // Omit next fixed frame slots. 606 while (sp < stack_base) { 607 if (is_valid_frame(sp, stack_base, stack_size)) { 608 return sp; 609 } 610 sp ++; 611 } 612 613 return NULL; 614} 615 616static void decode_instructions_at_pc(const char* header, 617 codeptr_t pc, int num_before, 618 int num_after, outputStream* st) { 619 // TODO: PPC port Disassembler::decode(pc, 16, 16, st); 620} 621 622 623void AixNativeCallstack::print_callstack_for_context(outputStream* st, const ucontext_t* context, 624 bool demangle, char* buf, size_t buf_size) { 625 626#define MAX_CALLSTACK_DEPTH 50 627 628 unsigned long* sp; 629 unsigned long* sp_last; 630 int frame; 631 632 // To print the first frame, use the current value of iar: 633 // current entry indicated by iar (the current pc) 634 codeptr_t cur_iar = 0; 635 stackptr_t cur_sp = 0; 636 codeptr_t cur_rtoc = 0; 637 codeptr_t cur_lr = 0; 638 639 const ucontext_t* uc = (const ucontext_t*) context; 640 641 // fallback: use the current context 642 ucontext_t local_context; 643 if (!uc) { 644 st->print_cr("No context given, using current context."); 645 if (getcontext(&local_context) == 0) { 646 uc = &local_context; 647 } else { 648 st->print_cr("No context given and getcontext failed. "); 649 return; 650 } 651 } 652 653 cur_iar = (codeptr_t)uc->uc_mcontext.jmp_context.iar; 654 cur_sp = (stackptr_t)uc->uc_mcontext.jmp_context.gpr[1]; 655 cur_rtoc = (codeptr_t)uc->uc_mcontext.jmp_context.gpr[2]; 656 cur_lr = (codeptr_t)uc->uc_mcontext.jmp_context.lr; 657 658 // syntax used here: 659 // n -------------- <-- stack_base, stack_to 660 // n-1 | | 661 // ... | older | 662 // ... | frames | | 663 // | | | stack grows downward 664 // ... | younger | | 665 // ... | frames | V 666 // | | 667 // |------------| <-- cur_sp, current stack ptr 668 // | | 669 // | unsused | 670 // | stack | 671 // | | 672 // . . 673 // . . 674 // . . 675 // . . 676 // | | 677 // 0 -------------- <-- stack_from 678 // 679 680 // Retrieve current stack base, size from the current thread. If there is none, 681 // retrieve it from the OS. 682 stackptr_t stack_base = NULL; 683 size_t stack_size = NULL; 684 { 685 AixMisc::stackbounds_t stackbounds; 686 if (!AixMisc::query_stack_bounds_for_current_thread(&stackbounds)) { 687 st->print_cr("Cannot retrieve stack bounds."); 688 return; 689 } 690 stack_base = (stackptr_t)stackbounds.base; 691 stack_size = stackbounds.size; 692 } 693 694 st->print_cr("------ current frame:"); 695 st->print("iar: " PTR64_FORMAT " ", p2i(cur_iar)); 696 print_info_for_pc(st, cur_iar, buf, buf_size, demangle); 697 st->cr(); 698 699 if (cur_iar && MiscUtils::is_readable_pointer(cur_iar)) { 700 decode_instructions_at_pc( 701 "Decoded instructions at iar:", 702 cur_iar, 32, 16, st); 703 } 704 705 // Print out lr too, which may be interesting if we did jump to some bogus location; 706 // in those cases the new frame is not built up yet and the caller location is only 707 // preserved via lr register. 708 st->print("lr: " PTR64_FORMAT " ", p2i(cur_lr)); 709 print_info_for_pc(st, cur_lr, buf, buf_size, demangle); 710 st->cr(); 711 712 if (cur_lr && MiscUtils::is_readable_pointer(cur_lr)) { 713 decode_instructions_at_pc( 714 "Decoded instructions at lr:", 715 cur_lr, 32, 16, st); 716 } 717 718 // Check and print sp. 719 st->print("sp: " PTR64_FORMAT " ", p2i(cur_sp)); 720 if (!is_valid_stackpointer(cur_sp, stack_base, stack_size)) { 721 st->print("(invalid) "); 722 goto cleanup; 723 } else { 724 st->print("(base - 0x%X) ", PTRDIFF_BYTES(stack_base, cur_sp)); 725 } 726 st->cr(); 727 728 // Check and print rtoc. 729 st->print("rtoc: " PTR64_FORMAT " ", p2i(cur_rtoc)); 730 if (cur_rtoc == NULL || cur_rtoc == (codeptr_t)-1 || 731 !MiscUtils::is_readable_pointer(cur_rtoc)) { 732 st->print("(invalid)"); 733 } else if (((uintptr_t)cur_rtoc) & 0x7) { 734 st->print("(unaligned)"); 735 } 736 st->cr(); 737 738 st->print_cr("|---stackaddr----| |----lrsave------|: <function name>"); 739 740 /// 741 // Walk callstack. 742 // 743 // (if no context was given, use the current stack) 744 sp = (unsigned long*)(*(unsigned long*)cur_sp); // Stack pointer 745 sp_last = cur_sp; 746 747 frame = 0; 748 749 while (frame < MAX_CALLSTACK_DEPTH) { 750 751 // Check sp. 752 bool retry = false; 753 if (sp == NULL) { 754 // The backchain pointer was NULL. This normally means the end of the chain. But the 755 // stack might be corrupted, and it may be worth looking for the stack chain. 756 if (is_valid_stackpointer(sp_last, stack_base, stack_size) && (stack_base - 0x10) > sp_last) { 757 // If we are not within <guess> 0x10 stackslots of the stack base, we assume that this 758 // is indeed not the end of the chain but that the stack was corrupted. So lets try to 759 // find the end of the chain. 760 st->print_cr("*** back chain pointer is NULL - end of stack or broken backchain ? ***"); 761 retry = true; 762 } else { 763 st->print_cr("*** end of backchain ***"); 764 goto end_walk_callstack; 765 } 766 } else if (!is_valid_stackpointer(sp, stack_base, stack_size)) { 767 st->print_cr("*** stack pointer invalid - backchain corrupted (" PTR_FORMAT ") ***", p2i(sp)); 768 retry = true; 769 } else if (sp < sp_last) { 770 st->print_cr("invalid stack pointer: " PTR_FORMAT " (not monotone raising)", p2i(sp)); 771 retry = true; 772 } 773 774 // If backchain is broken, try to recover, by manually scanning the stack for a pattern 775 // which looks like a valid stack. 776 if (retry) { 777 st->print_cr("trying to recover and find backchain..."); 778 sp = try_find_backchain(sp_last, stack_base, stack_size); 779 if (sp) { 780 st->print_cr("found something which looks like a backchain at " PTR64_FORMAT ", after 0x%x bytes... ", 781 p2i(sp), PTRDIFF_BYTES(sp, sp_last)); 782 } else { 783 st->print_cr("did not find a backchain, giving up."); 784 goto end_walk_callstack; 785 } 786 } 787 788 // Print stackframe. 789 print_stackframe(st, sp, buf, buf_size, demangle); 790 st->cr(); 791 frame ++; 792 793 // Next stack frame and link area. 794 sp_last = sp; 795 sp = (unsigned long*)(*sp); 796 } 797 798 // Prevent endless loops in case of invalid callstacks. 799 if (frame == MAX_CALLSTACK_DEPTH) { 800 st->print_cr("...(stopping after %d frames.", MAX_CALLSTACK_DEPTH); 801 } 802 803end_walk_callstack: 804 805 st->print_cr("-----------------------"); 806 807cleanup: 808 809 return; 810 811} 812 813 814bool AixMisc::query_stack_bounds_for_current_thread(stackbounds_t* out) { 815 816 // Information about this api can be found (a) in the pthread.h header and 817 // (b) in http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/pthread_getthrds_np.htm 818 // 819 // The use of this API to find out the current stack is kind of undefined. 820 // But after a lot of tries and asking IBM about it, I concluded that it is safe 821 // enough for cases where I let the pthread library create its stacks. For cases 822 // where I create an own stack and pass this to pthread_create, it seems not to 823 // work (the returned stack size in that case is 0). 824 825 pthread_t tid = pthread_self(); 826 struct __pthrdsinfo pinfo; 827 char dummy[1]; // Just needed to satisfy pthread_getthrds_np. 828 int dummy_size = sizeof(dummy); 829 830 memset(&pinfo, 0, sizeof(pinfo)); 831 832 const int rc = pthread_getthrds_np(&tid, PTHRDSINFO_QUERY_ALL, &pinfo, 833 sizeof(pinfo), dummy, &dummy_size); 834 835 if (rc != 0) { 836 fprintf(stderr, "pthread_getthrds_np failed (%d)\n", rc); 837 fflush(stdout); 838 return false; 839 } 840 841 // The following may happen when invoking pthread_getthrds_np on a pthread 842 // running on a user provided stack (when handing down a stack to pthread 843 // create, see pthread_attr_setstackaddr). 844 // Not sure what to do then. 845 if (pinfo.__pi_stackend == NULL || pinfo.__pi_stackaddr == NULL) { 846 fprintf(stderr, "pthread_getthrds_np - invalid values\n"); 847 fflush(stdout); 848 return false; 849 } 850 851 // Note: we get three values from pthread_getthrds_np: 852 // __pi_stackaddr, __pi_stacksize, __pi_stackend 853 // 854 // high addr --------------------- base, high 855 // 856 // | pthread internal data, like ~2K 857 // | 858 // | --------------------- __pi_stackend (usually not page aligned, (xxxxF890)) 859 // | 860 // | 861 // | 862 // | 863 // | 864 // | 865 // | --------------------- (__pi_stackend - __pi_stacksize) 866 // | 867 // | padding to align the following AIX guard pages, if enabled. 868 // | 869 // V --------------------- __pi_stackaddr low, base - size 870 // 871 // low addr AIX guard pages, if enabled (AIXTHREAD_GUARDPAGES > 0) 872 // 873 874 out->base = (address)pinfo.__pi_stackend; 875 address low = (address)pinfo.__pi_stackaddr; 876 out->size = out->base - low; 877 return true; 878 879} 880 881 882 883 884