1 //===-- DynamicLoaderHexagonDYLD.cpp --------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "lldb/Breakpoint/BreakpointLocation.h" 10 #include "lldb/Core/Module.h" 11 #include "lldb/Core/ModuleSpec.h" 12 #include "lldb/Core/PluginManager.h" 13 #include "lldb/Core/Section.h" 14 #include "lldb/Symbol/ObjectFile.h" 15 #include "lldb/Target/Process.h" 16 #include "lldb/Target/Target.h" 17 #include "lldb/Target/Thread.h" 18 #include "lldb/Target/ThreadPlanRunToAddress.h" 19 #include "lldb/Utility/LLDBLog.h" 20 #include "lldb/Utility/Log.h" 21 22 #include "DynamicLoaderHexagonDYLD.h" 23 24 #include <memory> 25 26 using namespace lldb; 27 using namespace lldb_private; 28 29 LLDB_PLUGIN_DEFINE(DynamicLoaderHexagonDYLD) 30 31 // Aidan 21/05/2014 32 // 33 // Notes about hexagon dynamic loading: 34 // 35 // When we connect to a target we find the dyld breakpoint address. We put 36 // a 37 // breakpoint there with a callback 'RendezvousBreakpointHit()'. 38 // 39 // It is possible to find the dyld structure address from the ELF symbol 40 // table, 41 // but in the case of the simulator it has not been initialized before the 42 // target calls dlinit(). 43 // 44 // We can only safely parse the dyld structure after we hit the dyld 45 // breakpoint 46 // since at that time we know dlinit() must have been called. 47 // 48 49 // Find the load address of a symbol 50 static lldb::addr_t findSymbolAddress(Process *proc, ConstString findName) { 51 assert(proc != nullptr); 52 53 ModuleSP module = proc->GetTarget().GetExecutableModule(); 54 assert(module.get() != nullptr); 55 56 ObjectFile *exe = module->GetObjectFile(); 57 assert(exe != nullptr); 58 59 lldb_private::Symtab *symtab = exe->GetSymtab(); 60 assert(symtab != nullptr); 61 62 for (size_t i = 0; i < symtab->GetNumSymbols(); i++) { 63 const Symbol *sym = symtab->SymbolAtIndex(i); 64 assert(sym != nullptr); 65 ConstString symName = sym->GetName(); 66 67 if (ConstString::Compare(findName, symName) == 0) { 68 Address addr = sym->GetAddress(); 69 return addr.GetLoadAddress(&proc->GetTarget()); 70 } 71 } 72 return LLDB_INVALID_ADDRESS; 73 } 74 75 void DynamicLoaderHexagonDYLD::Initialize() { 76 PluginManager::RegisterPlugin(GetPluginNameStatic(), 77 GetPluginDescriptionStatic(), CreateInstance); 78 } 79 80 void DynamicLoaderHexagonDYLD::Terminate() {} 81 82 llvm::StringRef DynamicLoaderHexagonDYLD::GetPluginDescriptionStatic() { 83 return "Dynamic loader plug-in that watches for shared library " 84 "loads/unloads in Hexagon processes."; 85 } 86 87 DynamicLoader *DynamicLoaderHexagonDYLD::CreateInstance(Process *process, 88 bool force) { 89 bool create = force; 90 if (!create) { 91 const llvm::Triple &triple_ref = 92 process->GetTarget().GetArchitecture().GetTriple(); 93 if (triple_ref.getArch() == llvm::Triple::hexagon) 94 create = true; 95 } 96 97 if (create) 98 return new DynamicLoaderHexagonDYLD(process); 99 return nullptr; 100 } 101 102 DynamicLoaderHexagonDYLD::DynamicLoaderHexagonDYLD(Process *process) 103 : DynamicLoader(process), m_rendezvous(process), 104 m_load_offset(LLDB_INVALID_ADDRESS), m_entry_point(LLDB_INVALID_ADDRESS), 105 m_dyld_bid(LLDB_INVALID_BREAK_ID) {} 106 107 DynamicLoaderHexagonDYLD::~DynamicLoaderHexagonDYLD() { 108 if (m_dyld_bid != LLDB_INVALID_BREAK_ID) { 109 m_process->GetTarget().RemoveBreakpointByID(m_dyld_bid); 110 m_dyld_bid = LLDB_INVALID_BREAK_ID; 111 } 112 } 113 114 void DynamicLoaderHexagonDYLD::DidAttach() { 115 ModuleSP executable; 116 addr_t load_offset; 117 118 executable = GetTargetExecutable(); 119 120 // Find the difference between the desired load address in the elf file and 121 // the real load address in memory 122 load_offset = ComputeLoadOffset(); 123 124 // Check that there is a valid executable 125 if (executable.get() == nullptr) 126 return; 127 128 // Disable JIT for hexagon targets because its not supported 129 m_process->SetCanJIT(false); 130 131 // Enable Interpreting of function call expressions 132 m_process->SetCanInterpretFunctionCalls(true); 133 134 // Add the current executable to the module list 135 ModuleList module_list; 136 module_list.Append(executable); 137 138 // Map the loaded sections of this executable 139 if (load_offset != LLDB_INVALID_ADDRESS) 140 UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset, true); 141 142 // AD: confirm this? 143 // Load into LLDB all of the currently loaded executables in the stub 144 LoadAllCurrentModules(); 145 146 // AD: confirm this? 147 // Callback for the target to give it the loaded module list 148 m_process->GetTarget().ModulesDidLoad(module_list); 149 150 // Try to set a breakpoint at the rendezvous breakpoint. DidLaunch uses 151 // ProbeEntry() instead. That sets a breakpoint, at the dyld breakpoint 152 // address, with a callback so that when hit, the dyld structure can be 153 // parsed. 154 if (!SetRendezvousBreakpoint()) { 155 // fail 156 } 157 } 158 159 void DynamicLoaderHexagonDYLD::DidLaunch() {} 160 161 /// Checks to see if the target module has changed, updates the target 162 /// accordingly and returns the target executable module. 163 ModuleSP DynamicLoaderHexagonDYLD::GetTargetExecutable() { 164 Target &target = m_process->GetTarget(); 165 ModuleSP executable = target.GetExecutableModule(); 166 167 // There is no executable 168 if (!executable.get()) 169 return executable; 170 171 // The target executable file does not exits 172 if (!FileSystem::Instance().Exists(executable->GetFileSpec())) 173 return executable; 174 175 // Prep module for loading 176 ModuleSpec module_spec(executable->GetFileSpec(), 177 executable->GetArchitecture()); 178 ModuleSP module_sp(new Module(module_spec)); 179 180 // Check if the executable has changed and set it to the target executable if 181 // they differ. 182 if (module_sp.get() && module_sp->GetUUID().IsValid() && 183 executable->GetUUID().IsValid()) { 184 // if the executable has changed ?? 185 if (module_sp->GetUUID() != executable->GetUUID()) 186 executable.reset(); 187 } else if (executable->FileHasChanged()) 188 executable.reset(); 189 190 if (executable.get()) 191 return executable; 192 193 // TODO: What case is this code used? 194 executable = target.GetOrCreateModule(module_spec, true /* notify */); 195 if (executable.get() != target.GetExecutableModulePointer()) { 196 // Don't load dependent images since we are in dyld where we will know and 197 // find out about all images that are loaded 198 target.SetExecutableModule(executable, eLoadDependentsNo); 199 } 200 201 return executable; 202 } 203 204 // AD: Needs to be updated? 205 Status DynamicLoaderHexagonDYLD::CanLoadImage() { return Status(); } 206 207 void DynamicLoaderHexagonDYLD::UpdateLoadedSections(ModuleSP module, 208 addr_t link_map_addr, 209 addr_t base_addr, 210 bool base_addr_is_offset) { 211 Target &target = m_process->GetTarget(); 212 const SectionList *sections = GetSectionListFromModule(module); 213 214 assert(sections && "SectionList missing from loaded module."); 215 216 m_loaded_modules[module] = link_map_addr; 217 218 const size_t num_sections = sections->GetSize(); 219 220 for (unsigned i = 0; i < num_sections; ++i) { 221 SectionSP section_sp(sections->GetSectionAtIndex(i)); 222 lldb::addr_t new_load_addr = section_sp->GetFileAddress() + base_addr; 223 224 // AD: 02/05/14 225 // since our memory map starts from address 0, we must not ignore 226 // sections that load to address 0. This violates the reference 227 // ELF spec, however is used for Hexagon. 228 229 // If the file address of the section is zero then this is not an 230 // allocatable/loadable section (property of ELF sh_addr). Skip it. 231 // if (new_load_addr == base_addr) 232 // continue; 233 234 target.SetSectionLoadAddress(section_sp, new_load_addr); 235 } 236 } 237 238 /// Removes the loaded sections from the target in \p module. 239 /// 240 /// \param module The module to traverse. 241 void DynamicLoaderHexagonDYLD::UnloadSections(const ModuleSP module) { 242 Target &target = m_process->GetTarget(); 243 const SectionList *sections = GetSectionListFromModule(module); 244 245 assert(sections && "SectionList missing from unloaded module."); 246 247 m_loaded_modules.erase(module); 248 249 const size_t num_sections = sections->GetSize(); 250 for (size_t i = 0; i < num_sections; ++i) { 251 SectionSP section_sp(sections->GetSectionAtIndex(i)); 252 target.SetSectionUnloaded(section_sp); 253 } 254 } 255 256 // Place a breakpoint on <_rtld_debug_state> 257 bool DynamicLoaderHexagonDYLD::SetRendezvousBreakpoint() { 258 Log *log = GetLog(LLDBLog::DynamicLoader); 259 260 // This is the original code, which want to look in the rendezvous structure 261 // to find the breakpoint address. Its backwards for us, since we can easily 262 // find the breakpoint address, since it is exported in our executable. We 263 // however know that we cant read the Rendezvous structure until we have hit 264 // the breakpoint once. 265 const ConstString dyldBpName("_rtld_debug_state"); 266 addr_t break_addr = findSymbolAddress(m_process, dyldBpName); 267 268 Target &target = m_process->GetTarget(); 269 270 // Do not try to set the breakpoint if we don't know where to put it 271 if (break_addr == LLDB_INVALID_ADDRESS) { 272 LLDB_LOGF(log, "Unable to locate _rtld_debug_state breakpoint address"); 273 274 return false; 275 } 276 277 // Save the address of the rendezvous structure 278 m_rendezvous.SetBreakAddress(break_addr); 279 280 // If we haven't set the breakpoint before then set it 281 if (m_dyld_bid == LLDB_INVALID_BREAK_ID) { 282 Breakpoint *dyld_break = 283 target.CreateBreakpoint(break_addr, true, false).get(); 284 dyld_break->SetCallback(RendezvousBreakpointHit, this, true); 285 dyld_break->SetBreakpointKind("shared-library-event"); 286 m_dyld_bid = dyld_break->GetID(); 287 288 // Make sure our breakpoint is at the right address. 289 assert(target.GetBreakpointByID(m_dyld_bid) 290 ->FindLocationByAddress(break_addr) 291 ->GetBreakpoint() 292 .GetID() == m_dyld_bid); 293 294 if (log && dyld_break == nullptr) 295 LLDB_LOGF(log, "Failed to create _rtld_debug_state breakpoint"); 296 297 // check we have successfully set bp 298 return (dyld_break != nullptr); 299 } else 300 // rendezvous already set 301 return true; 302 } 303 304 // We have just hit our breakpoint at <_rtld_debug_state> 305 bool DynamicLoaderHexagonDYLD::RendezvousBreakpointHit( 306 void *baton, StoppointCallbackContext *context, user_id_t break_id, 307 user_id_t break_loc_id) { 308 Log *log = GetLog(LLDBLog::DynamicLoader); 309 310 LLDB_LOGF(log, "Rendezvous breakpoint hit!"); 311 312 DynamicLoaderHexagonDYLD *dyld_instance = nullptr; 313 dyld_instance = static_cast<DynamicLoaderHexagonDYLD *>(baton); 314 315 // if the dyld_instance is still not valid then try to locate it on the 316 // symbol table 317 if (!dyld_instance->m_rendezvous.IsValid()) { 318 Process *proc = dyld_instance->m_process; 319 320 const ConstString dyldStructName("_rtld_debug"); 321 addr_t structAddr = findSymbolAddress(proc, dyldStructName); 322 323 if (structAddr != LLDB_INVALID_ADDRESS) { 324 dyld_instance->m_rendezvous.SetRendezvousAddress(structAddr); 325 326 LLDB_LOGF(log, "Found _rtld_debug structure @ 0x%08" PRIx64, structAddr); 327 } else { 328 LLDB_LOGF(log, "Unable to resolve the _rtld_debug structure"); 329 } 330 } 331 332 dyld_instance->RefreshModules(); 333 334 // Return true to stop the target, false to just let the target run. 335 return dyld_instance->GetStopWhenImagesChange(); 336 } 337 338 /// Helper method for RendezvousBreakpointHit. Updates LLDB's current set 339 /// of loaded modules. 340 void DynamicLoaderHexagonDYLD::RefreshModules() { 341 Log *log = GetLog(LLDBLog::DynamicLoader); 342 343 if (!m_rendezvous.Resolve()) 344 return; 345 346 HexagonDYLDRendezvous::iterator I; 347 HexagonDYLDRendezvous::iterator E; 348 349 ModuleList &loaded_modules = m_process->GetTarget().GetImages(); 350 351 if (m_rendezvous.ModulesDidLoad()) { 352 ModuleList new_modules; 353 354 E = m_rendezvous.loaded_end(); 355 for (I = m_rendezvous.loaded_begin(); I != E; ++I) { 356 FileSpec file(I->path); 357 FileSystem::Instance().Resolve(file); 358 ModuleSP module_sp = 359 LoadModuleAtAddress(file, I->link_addr, I->base_addr, true); 360 if (module_sp.get()) { 361 loaded_modules.AppendIfNeeded(module_sp); 362 new_modules.Append(module_sp); 363 } 364 365 if (log) { 366 LLDB_LOGF(log, "Target is loading '%s'", I->path.c_str()); 367 if (!module_sp.get()) 368 LLDB_LOGF(log, "LLDB failed to load '%s'", I->path.c_str()); 369 else 370 LLDB_LOGF(log, "LLDB successfully loaded '%s'", I->path.c_str()); 371 } 372 } 373 m_process->GetTarget().ModulesDidLoad(new_modules); 374 } 375 376 if (m_rendezvous.ModulesDidUnload()) { 377 ModuleList old_modules; 378 379 E = m_rendezvous.unloaded_end(); 380 for (I = m_rendezvous.unloaded_begin(); I != E; ++I) { 381 FileSpec file(I->path); 382 FileSystem::Instance().Resolve(file); 383 ModuleSpec module_spec(file); 384 ModuleSP module_sp = loaded_modules.FindFirstModule(module_spec); 385 386 if (module_sp.get()) { 387 old_modules.Append(module_sp); 388 UnloadSections(module_sp); 389 } 390 391 LLDB_LOGF(log, "Target is unloading '%s'", I->path.c_str()); 392 } 393 loaded_modules.Remove(old_modules); 394 m_process->GetTarget().ModulesDidUnload(old_modules, false); 395 } 396 } 397 398 // AD: This is very different to the Static Loader code. 399 // It may be wise to look over this and its relation to stack 400 // unwinding. 401 ThreadPlanSP 402 DynamicLoaderHexagonDYLD::GetStepThroughTrampolinePlan(Thread &thread, 403 bool stop) { 404 ThreadPlanSP thread_plan_sp; 405 406 StackFrame *frame = thread.GetStackFrameAtIndex(0).get(); 407 const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol); 408 Symbol *sym = context.symbol; 409 410 if (sym == nullptr || !sym->IsTrampoline()) 411 return thread_plan_sp; 412 413 const ConstString sym_name = 414 sym->GetMangled().GetName(Mangled::ePreferMangled); 415 if (!sym_name) 416 return thread_plan_sp; 417 418 SymbolContextList target_symbols; 419 Target &target = thread.GetProcess()->GetTarget(); 420 const ModuleList &images = target.GetImages(); 421 422 images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols); 423 if (target_symbols.GetSize() == 0) 424 return thread_plan_sp; 425 426 typedef std::vector<lldb::addr_t> AddressVector; 427 AddressVector addrs; 428 for (const SymbolContext &context : target_symbols) { 429 AddressRange range; 430 context.GetAddressRange(eSymbolContextEverything, 0, false, range); 431 lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target); 432 if (addr != LLDB_INVALID_ADDRESS) 433 addrs.push_back(addr); 434 } 435 436 if (addrs.size() > 0) { 437 AddressVector::iterator start = addrs.begin(); 438 AddressVector::iterator end = addrs.end(); 439 440 llvm::sort(start, end); 441 addrs.erase(std::unique(start, end), end); 442 thread_plan_sp = 443 std::make_shared<ThreadPlanRunToAddress>(thread, addrs, stop); 444 } 445 446 return thread_plan_sp; 447 } 448 449 /// Helper for the entry breakpoint callback. Resolves the load addresses 450 /// of all dependent modules. 451 void DynamicLoaderHexagonDYLD::LoadAllCurrentModules() { 452 HexagonDYLDRendezvous::iterator I; 453 HexagonDYLDRendezvous::iterator E; 454 ModuleList module_list; 455 456 if (!m_rendezvous.Resolve()) { 457 Log *log = GetLog(LLDBLog::DynamicLoader); 458 LLDB_LOGF( 459 log, 460 "DynamicLoaderHexagonDYLD::%s unable to resolve rendezvous address", 461 __FUNCTION__); 462 return; 463 } 464 465 // The rendezvous class doesn't enumerate the main module, so track that 466 // ourselves here. 467 ModuleSP executable = GetTargetExecutable(); 468 m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress(); 469 470 for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) { 471 const char *module_path = I->path.c_str(); 472 FileSpec file(module_path); 473 ModuleSP module_sp = 474 LoadModuleAtAddress(file, I->link_addr, I->base_addr, true); 475 if (module_sp.get()) { 476 module_list.Append(module_sp); 477 } else { 478 Log *log = GetLog(LLDBLog::DynamicLoader); 479 LLDB_LOGF(log, 480 "DynamicLoaderHexagonDYLD::%s failed loading module %s at " 481 "0x%" PRIx64, 482 __FUNCTION__, module_path, I->base_addr); 483 } 484 } 485 486 m_process->GetTarget().ModulesDidLoad(module_list); 487 } 488 489 /// Computes a value for m_load_offset returning the computed address on 490 /// success and LLDB_INVALID_ADDRESS on failure. 491 addr_t DynamicLoaderHexagonDYLD::ComputeLoadOffset() { 492 // Here we could send a GDB packet to know the load offset 493 // 494 // send: $qOffsets#4b 495 // get: Text=0;Data=0;Bss=0 496 // 497 // Currently qOffsets is not supported by pluginProcessGDBRemote 498 // 499 return 0; 500 } 501 502 // Here we must try to read the entry point directly from the elf header. This 503 // is possible if the process is not relocatable or dynamically linked. 504 // 505 // an alternative is to look at the PC if we can be sure that we have connected 506 // when the process is at the entry point. 507 // I dont think that is reliable for us. 508 addr_t DynamicLoaderHexagonDYLD::GetEntryPoint() { 509 if (m_entry_point != LLDB_INVALID_ADDRESS) 510 return m_entry_point; 511 // check we have a valid process 512 if (m_process == nullptr) 513 return LLDB_INVALID_ADDRESS; 514 // Get the current executable module 515 Module &module = *(m_process->GetTarget().GetExecutableModule().get()); 516 // Get the object file (elf file) for this module 517 lldb_private::ObjectFile &object = *(module.GetObjectFile()); 518 // Check if the file is executable (ie, not shared object or relocatable) 519 if (object.IsExecutable()) { 520 // Get the entry point address for this object 521 lldb_private::Address entry = object.GetEntryPointAddress(); 522 // Return the entry point address 523 return entry.GetFileAddress(); 524 } 525 // No idea so back out 526 return LLDB_INVALID_ADDRESS; 527 } 528 529 const SectionList *DynamicLoaderHexagonDYLD::GetSectionListFromModule( 530 const ModuleSP module) const { 531 SectionList *sections = nullptr; 532 if (module.get()) { 533 ObjectFile *obj_file = module->GetObjectFile(); 534 if (obj_file) { 535 sections = obj_file->GetSectionList(); 536 } 537 } 538 return sections; 539 } 540 541 static int ReadInt(Process *process, addr_t addr) { 542 Status error; 543 int value = (int)process->ReadUnsignedIntegerFromMemory( 544 addr, sizeof(uint32_t), 0, error); 545 if (error.Fail()) 546 return -1; 547 else 548 return value; 549 } 550 551 lldb::addr_t 552 DynamicLoaderHexagonDYLD::GetThreadLocalData(const lldb::ModuleSP module, 553 const lldb::ThreadSP thread, 554 lldb::addr_t tls_file_addr) { 555 auto it = m_loaded_modules.find(module); 556 if (it == m_loaded_modules.end()) 557 return LLDB_INVALID_ADDRESS; 558 559 addr_t link_map = it->second; 560 if (link_map == LLDB_INVALID_ADDRESS) 561 return LLDB_INVALID_ADDRESS; 562 563 const HexagonDYLDRendezvous::ThreadInfo &metadata = 564 m_rendezvous.GetThreadInfo(); 565 if (!metadata.valid) 566 return LLDB_INVALID_ADDRESS; 567 568 // Get the thread pointer. 569 addr_t tp = thread->GetThreadPointer(); 570 if (tp == LLDB_INVALID_ADDRESS) 571 return LLDB_INVALID_ADDRESS; 572 573 // Find the module's modid. 574 int modid = ReadInt(m_process, link_map + metadata.modid_offset); 575 if (modid == -1) 576 return LLDB_INVALID_ADDRESS; 577 578 // Lookup the DTV structure for this thread. 579 addr_t dtv_ptr = tp + metadata.dtv_offset; 580 addr_t dtv = ReadPointer(dtv_ptr); 581 if (dtv == LLDB_INVALID_ADDRESS) 582 return LLDB_INVALID_ADDRESS; 583 584 // Find the TLS block for this module. 585 addr_t dtv_slot = dtv + metadata.dtv_slot_size * modid; 586 addr_t tls_block = ReadPointer(dtv_slot + metadata.tls_offset); 587 588 Module *mod = module.get(); 589 Log *log = GetLog(LLDBLog::DynamicLoader); 590 LLDB_LOGF(log, 591 "DynamicLoaderHexagonDYLD::Performed TLS lookup: " 592 "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64 593 ", modid=%i, tls_block=0x%" PRIx64, 594 mod->GetObjectName().AsCString(""), link_map, tp, modid, tls_block); 595 596 if (tls_block == LLDB_INVALID_ADDRESS) 597 return LLDB_INVALID_ADDRESS; 598 else 599 return tls_block + tls_file_addr; 600 } 601