stackwalker_mips.cc
1 // Copyright 2013 Google LLC 2 // 3 // Redistribution and use in source and binary forms, with or without 4 // modification, are permitted provided that the following conditions are 5 // met: 6 // 7 // * Redistributions of source code must retain the above copyright 8 // notice, this list of conditions and the following disclaimer. 9 // * Redistributions in binary form must reproduce the above 10 // copyright notice, this list of conditions and the following disclaimer 11 // in the documentation and/or other materials provided with the 12 // distribution. 13 // * Neither the name of Google LLC nor the names of its 14 // contributors may be used to endorse or promote products derived from 15 // this software without specific prior written permission. 16 // 17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 29 // stackwalker_mips.cc: MIPS-specific stackwalker. 30 // 31 // See stackwalker_mips.h for documentation. 32 // 33 // Author: Tata Elxsi 34 35 #ifdef HAVE_CONFIG_H 36 #include <config.h> // Must come first 37 #endif 38 39 #include "common/scoped_ptr.h" 40 #include "google_breakpad/processor/call_stack.h" 41 #include "google_breakpad/processor/code_modules.h" 42 #include "google_breakpad/processor/memory_region.h" 43 #include "google_breakpad/processor/source_line_resolver_interface.h" 44 #include "google_breakpad/processor/stack_frame_cpu.h" 45 #include "processor/cfi_frame_info.h" 46 #include "processor/logging.h" 47 #include "processor/postfix_evaluator-inl.h" 48 #include "processor/stackwalker_mips.h" 49 #include "processor/windows_frame_info.h" 50 #include "google_breakpad/common/minidump_cpu_mips.h" 51 52 namespace google_breakpad { 53 54 StackwalkerMIPS::StackwalkerMIPS(const SystemInfo* system_info, 55 const MDRawContextMIPS* context, 56 MemoryRegion* memory, 57 const CodeModules* modules, 58 StackFrameSymbolizer* resolver_helper) 59 : Stackwalker(system_info, memory, modules, resolver_helper), 60 context_(context) { 61 if (memory_) { 62 if (context_->context_flags & MD_CONTEXT_MIPS64 ) { 63 if (0xffffffffffffffff - memory_->GetBase() < memory_->GetSize() - 1) { 64 BPLOG(ERROR) << "Memory out of range for stackwalking mips64: " 65 << HexString(memory_->GetBase()) 66 << "+" 67 << HexString(memory_->GetSize()); 68 memory_ = NULL; 69 } 70 } else { 71 if (0xffffffff - memory_->GetBase() < memory_->GetSize() - 1) { 72 BPLOG(ERROR) << "Memory out of range for stackwalking mips32: " 73 << HexString(memory_->GetBase()) 74 << "+" 75 << HexString(memory_->GetSize()); 76 memory_ = NULL; 77 } 78 } 79 } 80 } 81 82 StackFrame* StackwalkerMIPS::GetContextFrame() { 83 if (!context_) { 84 BPLOG(ERROR) << "Can't get context frame without context."; 85 return NULL; 86 } 87 88 StackFrameMIPS* frame = new StackFrameMIPS(); 89 90 // The instruction pointer is stored directly in a register, so pull it 91 // straight out of the CPU context structure. 92 frame->context = *context_; 93 frame->context_validity = StackFrameMIPS::CONTEXT_VALID_ALL; 94 frame->trust = StackFrame::FRAME_TRUST_CONTEXT; 95 frame->instruction = frame->context.epc; 96 97 return frame; 98 } 99 100 // Register names for mips. 101 static const char* const kRegisterNames[] = { 102 "$zero", "$at", "$v0", "$v1", "$a0", "$a1", "$a2", "$a3", "$to", "$t1", 103 "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$s0", "$s1", "$s2", "$s3", 104 "$s4", "$s5", "$s6", "$s7", "$t8", "$t9", "$k0", "$k1", "$gp", "$sp", 105 "$fp", "$ra", NULL 106 // TODO(gordanac): add float point save registers 107 }; 108 109 StackFrameMIPS* StackwalkerMIPS::GetCallerByCFIFrameInfo( 110 const vector<StackFrame*>& frames, 111 CFIFrameInfo* cfi_frame_info) { 112 StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); 113 114 if (context_->context_flags & MD_CONTEXT_MIPS) { 115 uint32_t pc = 0; 116 117 // Populate a dictionary with the valid register values in last_frame. 118 CFIFrameInfo::RegisterValueMap<uint32_t> callee_registers; 119 // Use the STACK CFI data to recover the caller's register values. 120 CFIFrameInfo::RegisterValueMap<uint32_t> caller_registers; 121 122 for (int i = 0; kRegisterNames[i]; ++i) { 123 caller_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; 124 callee_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; 125 } 126 127 if (!cfi_frame_info->FindCallerRegs(callee_registers, *memory_, 128 &caller_registers)) { 129 return NULL; 130 } 131 132 CFIFrameInfo::RegisterValueMap<uint32_t>::const_iterator entry = 133 caller_registers.find(".cfa"); 134 135 if (entry != caller_registers.end()) { 136 caller_registers["$sp"] = entry->second; 137 } 138 139 entry = caller_registers.find(".ra"); 140 if (entry != caller_registers.end()) { 141 caller_registers["$ra"] = entry->second; 142 pc = entry->second - 2 * sizeof(pc); 143 } 144 caller_registers["$pc"] = pc; 145 // Construct a new stack frame given the values the CFI recovered. 146 scoped_ptr<StackFrameMIPS> frame(new StackFrameMIPS()); 147 148 for (int i = 0; kRegisterNames[i]; ++i) { 149 CFIFrameInfo::RegisterValueMap<uint32_t>::const_iterator caller_entry = 150 caller_registers.find(kRegisterNames[i]); 151 152 if (caller_entry != caller_registers.end()) { 153 // The value of this register is recovered; fill the context with the 154 // value from caller_registers. 155 frame->context.iregs[i] = caller_entry->second; 156 frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); 157 } else if (((i >= INDEX_MIPS_REG_S0 && i <= INDEX_MIPS_REG_S7) || 158 (i > INDEX_MIPS_REG_GP && i < INDEX_MIPS_REG_RA)) && 159 (last_frame->context_validity & 160 StackFrameMIPS::RegisterValidFlag(i))) { 161 // If the STACK CFI data doesn't mention some callee-save register, and 162 // it is valid in the callee, assume the callee has not yet changed it. 163 // Calee-save registers according to the MIPS o32 ABI specification are: 164 // $s0 to $s7 165 // $sp, $s8 166 frame->context.iregs[i] = last_frame->context.iregs[i]; 167 frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); 168 } 169 } 170 171 frame->context.epc = caller_registers["$pc"]; 172 frame->instruction = caller_registers["$pc"]; 173 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; 174 175 frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = caller_registers["$ra"]; 176 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; 177 178 frame->trust = StackFrame::FRAME_TRUST_CFI; 179 180 return frame.release(); 181 } else { 182 uint64_t pc = 0; 183 184 // Populate a dictionary with the valid register values in last_frame. 185 CFIFrameInfo::RegisterValueMap<uint64_t> callee_registers; 186 // Use the STACK CFI data to recover the caller's register values. 187 CFIFrameInfo::RegisterValueMap<uint64_t> caller_registers; 188 189 for (int i = 0; kRegisterNames[i]; ++i) { 190 caller_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; 191 callee_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; 192 } 193 194 if (!cfi_frame_info->FindCallerRegs(callee_registers, *memory_, 195 &caller_registers)) { 196 return NULL; 197 } 198 199 CFIFrameInfo::RegisterValueMap<uint64_t>::const_iterator entry = 200 caller_registers.find(".cfa"); 201 202 if (entry != caller_registers.end()) { 203 caller_registers["$sp"] = entry->second; 204 } 205 206 entry = caller_registers.find(".ra"); 207 if (entry != caller_registers.end()) { 208 caller_registers["$ra"] = entry->second; 209 pc = entry->second - 2 * sizeof(pc); 210 } 211 caller_registers["$pc"] = pc; 212 // Construct a new stack frame given the values the CFI recovered. 213 scoped_ptr<StackFrameMIPS> frame(new StackFrameMIPS()); 214 215 for (int i = 0; kRegisterNames[i]; ++i) { 216 CFIFrameInfo::RegisterValueMap<uint64_t>::const_iterator caller_entry = 217 caller_registers.find(kRegisterNames[i]); 218 219 if (caller_entry != caller_registers.end()) { 220 // The value of this register is recovered; fill the context with the 221 // value from caller_registers. 222 frame->context.iregs[i] = caller_entry->second; 223 frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); 224 } else if (((i >= INDEX_MIPS_REG_S0 && i <= INDEX_MIPS_REG_S7) || 225 (i >= INDEX_MIPS_REG_GP && i < INDEX_MIPS_REG_RA)) && 226 (last_frame->context_validity & 227 StackFrameMIPS::RegisterValidFlag(i))) { 228 // If the STACK CFI data doesn't mention some callee-save register, and 229 // it is valid in the callee, assume the callee has not yet changed it. 230 // Calee-save registers according to the MIPS o32 ABI specification are: 231 // $s0 to $s7 232 // $sp, $s8 233 frame->context.iregs[i] = last_frame->context.iregs[i]; 234 frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); 235 } 236 } 237 238 frame->context.epc = caller_registers["$pc"]; 239 frame->instruction = caller_registers["$pc"]; 240 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; 241 242 frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = caller_registers["$ra"]; 243 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; 244 245 frame->trust = StackFrame::FRAME_TRUST_CFI; 246 247 return frame.release(); 248 } 249 } 250 251 StackFrame* StackwalkerMIPS::GetCallerFrame(const CallStack* stack, 252 bool stack_scan_allowed) { 253 if (!memory_ || !stack) { 254 BPLOG(ERROR) << "Can't get caller frame without memory or stack"; 255 return NULL; 256 } 257 258 const vector<StackFrame*>& frames = *stack->frames(); 259 StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); 260 scoped_ptr<StackFrameMIPS> new_frame; 261 262 // See if there is DWARF call frame information covering this address. 263 scoped_ptr<CFIFrameInfo> cfi_frame_info( 264 frame_symbolizer_->FindCFIFrameInfo(last_frame)); 265 if (cfi_frame_info.get()) 266 new_frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get())); 267 268 // If caller frame is not found in CFI try analyzing the stack. 269 if (stack_scan_allowed && !new_frame.get()) { 270 new_frame.reset(GetCallerByStackScan(frames)); 271 } 272 273 // If nothing worked, tell the caller. 274 if (!new_frame.get()) { 275 return NULL; 276 } 277 278 // Should we terminate the stack walk? (end-of-stack or broken invariant) 279 if (TerminateWalk(new_frame->context.epc, 280 new_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP], 281 last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP], 282 /*first_unwind=*/last_frame->trust == 283 StackFrame::FRAME_TRUST_CONTEXT)) { 284 return NULL; 285 } 286 287 return new_frame.release(); 288 } 289 290 StackFrameMIPS* StackwalkerMIPS::GetCallerByStackScan( 291 const vector<StackFrame*>& frames) { 292 const uint32_t kMaxFrameStackSize = 1024; 293 const uint32_t kMinArgsOnStack = 4; 294 295 StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); 296 297 if (context_->context_flags & MD_CONTEXT_MIPS) { 298 uint32_t last_sp = last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP]; 299 uint32_t caller_pc, caller_sp, caller_fp; 300 301 // Return address cannot be obtained directly. 302 // Force stackwalking. 303 304 // We cannot use frame pointer to get the return address. 305 // We'll scan the stack for a 306 // return address. This can happen if last_frame is executing code 307 // for a module for which we don't have symbols. 308 int count = kMaxFrameStackSize / sizeof(caller_pc); 309 310 if (frames.size() > 1) { 311 // In case of mips32 ABI stack frame of a nonleaf function 312 // must have minimum stack frame assigned for 4 arguments (4 words). 313 // Move stack pointer for 4 words to avoid reporting non-existing frames 314 // for all frames except the topmost one. 315 // There is no way of knowing if topmost frame belongs to a leaf or 316 // a nonleaf function. 317 last_sp += kMinArgsOnStack * sizeof(caller_pc); 318 // Adjust 'count' so that return address is scanned only in limits 319 // of one stack frame. 320 count -= kMinArgsOnStack; 321 } 322 323 do { 324 // Scanning for return address from stack pointer of the last frame. 325 if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc, count)) { 326 // If we can't find an instruction pointer even with stack scanning, 327 // give up. 328 BPLOG(ERROR) << " ScanForReturnAddress failed "; 329 return NULL; 330 } 331 // Get $fp stored in the stack frame. 332 if (!memory_->GetMemoryAtAddress(caller_sp - sizeof(caller_pc), 333 &caller_fp)) { 334 BPLOG(INFO) << " GetMemoryAtAddress for fp failed " ; 335 return NULL; 336 } 337 338 count = count - (caller_sp - last_sp) / sizeof(caller_pc); 339 // Now scan the next address in the stack. 340 last_sp = caller_sp + sizeof(caller_pc); 341 } while ((caller_fp - caller_sp >= kMaxFrameStackSize) && count > 0); 342 343 if (!count) { 344 BPLOG(INFO) << " No frame found " ; 345 return NULL; 346 } 347 348 // ScanForReturnAddress found a reasonable return address. Advance 349 // $sp to the location above the one where the return address was 350 // found. 351 caller_sp += sizeof(caller_pc); 352 // caller_pc is actually containing $ra value; 353 // $pc is two instructions before $ra, 354 // so the caller_pc needs to be decremented accordingly. 355 caller_pc -= 2 * sizeof(caller_pc); 356 357 // Create a new stack frame (ownership will be transferred to the caller) 358 // and fill it in. 359 StackFrameMIPS* frame = new StackFrameMIPS(); 360 frame->trust = StackFrame::FRAME_TRUST_SCAN; 361 frame->context = last_frame->context; 362 frame->context.epc = caller_pc; 363 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; 364 frame->instruction = caller_pc; 365 366 frame->context.iregs[MD_CONTEXT_MIPS_REG_SP] = caller_sp; 367 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_SP; 368 frame->context.iregs[MD_CONTEXT_MIPS_REG_FP] = caller_fp; 369 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_FP; 370 371 frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = 372 caller_pc + 2 * sizeof(caller_pc); 373 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; 374 375 return frame; 376 } else { 377 uint64_t last_sp = last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP]; 378 uint64_t caller_pc, caller_sp, caller_fp; 379 380 // Return address cannot be obtained directly. 381 // Force stackwalking. 382 383 // We cannot use frame pointer to get the return address. 384 // We'll scan the stack for a 385 // return address. This can happen if last_frame is executing code 386 // for a module for which we don't have symbols. 387 int count = kMaxFrameStackSize / sizeof(caller_pc); 388 389 do { 390 // Scanning for return address from stack pointer of the last frame. 391 if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc, count)) { 392 // If we can't find an instruction pointer even with stack scanning, 393 // give up. 394 BPLOG(ERROR) << " ScanForReturnAddress failed "; 395 return NULL; 396 } 397 // Get $fp stored in the stack frame. 398 if (!memory_->GetMemoryAtAddress(caller_sp - sizeof(caller_pc), 399 &caller_fp)) { 400 BPLOG(INFO) << " GetMemoryAtAddress for fp failed " ; 401 return NULL; 402 } 403 404 count = count - (caller_sp - last_sp) / sizeof(caller_pc); 405 // Now scan the next address in the stack. 406 last_sp = caller_sp + sizeof(caller_pc); 407 } while ((caller_fp - caller_sp >= kMaxFrameStackSize) && count > 0); 408 409 if (!count) { 410 BPLOG(INFO) << " No frame found " ; 411 return NULL; 412 } 413 414 // ScanForReturnAddress found a reasonable return address. Advance 415 // $sp to the location above the one where the return address was 416 // found. 417 caller_sp += sizeof(caller_pc); 418 // caller_pc is actually containing $ra value; 419 // $pc is two instructions before $ra, 420 // so the caller_pc needs to be decremented accordingly. 421 caller_pc -= 2 * sizeof(caller_pc); 422 423 // Create a new stack frame (ownership will be transferred to the caller) 424 // and fill it in. 425 StackFrameMIPS* frame = new StackFrameMIPS(); 426 frame->trust = StackFrame::FRAME_TRUST_SCAN; 427 frame->context = last_frame->context; 428 frame->context.epc = caller_pc; 429 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; 430 frame->instruction = caller_pc; 431 432 frame->context.iregs[MD_CONTEXT_MIPS_REG_SP] = caller_sp; 433 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_SP; 434 frame->context.iregs[MD_CONTEXT_MIPS_REG_FP] = caller_fp; 435 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_FP; 436 437 frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = 438 caller_pc + 2 * sizeof(caller_pc); 439 frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; 440 441 return frame; 442 } 443 } 444 445 } // namespace google_breakpad 446