| // Copyright (c) 2013 Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| // stackwalker_mips.cc: MIPS-specific stackwalker. |
| // |
| // See stackwalker_mips.h for documentation. |
| // |
| // Author: Tata Elxsi |
| |
| #include "common/scoped_ptr.h" |
| #include "google_breakpad/processor/call_stack.h" |
| #include "google_breakpad/processor/code_modules.h" |
| #include "google_breakpad/processor/memory_region.h" |
| #include "google_breakpad/processor/source_line_resolver_interface.h" |
| #include "google_breakpad/processor/stack_frame_cpu.h" |
| #include "processor/cfi_frame_info.h" |
| #include "processor/logging.h" |
| #include "processor/postfix_evaluator-inl.h" |
| #include "processor/stackwalker_mips.h" |
| #include "processor/windows_frame_info.h" |
| #include "google_breakpad/common/minidump_cpu_mips.h" |
| |
| namespace google_breakpad { |
| |
| StackwalkerMIPS::StackwalkerMIPS(const SystemInfo* system_info, |
| const MDRawContextMIPS* context, |
| MemoryRegion* memory, |
| const CodeModules* modules, |
| StackFrameSymbolizer* resolver_helper) |
| : Stackwalker(system_info, memory, modules, resolver_helper), |
| context_(context) { |
| if (memory_ && memory_->GetBase() + memory_->GetSize() - 1 > 0xffffffff) { |
| BPLOG(ERROR) << "Memory out of range for stackwalking: " |
| << HexString(memory_->GetBase()) |
| << "+" |
| << HexString(memory_->GetSize()); |
| memory_ = NULL; |
| } |
| } |
| |
| StackFrame* StackwalkerMIPS::GetContextFrame() { |
| if (!context_) { |
| BPLOG(ERROR) << "Can't get context frame without context."; |
| return NULL; |
| } |
| |
| StackFrameMIPS* frame = new StackFrameMIPS(); |
| |
| // The instruction pointer is stored directly in a register, so pull it |
| // straight out of the CPU context structure. |
| frame->context = *context_; |
| frame->context_validity = StackFrameMIPS::CONTEXT_VALID_ALL; |
| frame->trust = StackFrame::FRAME_TRUST_CONTEXT; |
| frame->instruction = frame->context.epc; |
| |
| return frame; |
| } |
| |
| // Register names for mips. |
| static const char* const kRegisterNames[] = { |
| "$zero", "$at", "$v0", "$v1", "$a0", "$a1", "$a2", "$a3", "$to", "$t1", |
| "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$s0", "$s1", "$s2", "$s3", |
| "$s4", "$s5", "$s6", "$s7", "$t8", "$t9", "$k0", "$k1", "$gp", "$sp", |
| "$fp", "$ra", NULL |
| // TODO(gordanac): add float point save registers |
| }; |
| |
| StackFrameMIPS* StackwalkerMIPS::GetCallerByCFIFrameInfo( |
| const vector<StackFrame*>& frames, |
| CFIFrameInfo* cfi_frame_info) { |
| StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); |
| |
| uint32_t sp = 0, pc = 0; |
| |
| // Populate a dictionary with the valid register values in last_frame. |
| CFIFrameInfo::RegisterValueMap<uint32_t> callee_registers; |
| // Use the STACK CFI data to recover the caller's register values. |
| CFIFrameInfo::RegisterValueMap<uint32_t> caller_registers; |
| |
| for (int i = 0; kRegisterNames[i]; ++i) { |
| caller_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; |
| callee_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; |
| } |
| |
| if (!cfi_frame_info->FindCallerRegs(callee_registers, *memory_, |
| &caller_registers)) { |
| return NULL; |
| } |
| |
| CFIFrameInfo::RegisterValueMap<uint32_t>::const_iterator entry = |
| caller_registers.find(".cfa"); |
| |
| if (entry != caller_registers.end()) { |
| sp = entry->second; |
| caller_registers["$sp"] = entry->second; |
| } |
| |
| entry = caller_registers.find(".ra"); |
| if (entry != caller_registers.end()) { |
| caller_registers["$ra"] = entry->second; |
| pc = entry->second - 2 * sizeof(pc); |
| } |
| caller_registers["$pc"] = pc; |
| // Construct a new stack frame given the values the CFI recovered. |
| scoped_ptr<StackFrameMIPS> frame(new StackFrameMIPS()); |
| |
| for (int i = 0; kRegisterNames[i]; ++i) { |
| CFIFrameInfo::RegisterValueMap<uint32_t>::const_iterator caller_entry = |
| caller_registers.find(kRegisterNames[i]); |
| |
| if (caller_entry != caller_registers.end()) { |
| // The value of this register is recovered; fill the context with the |
| // value from caller_registers. |
| frame->context.iregs[i] = caller_entry->second; |
| frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); |
| } else if (((i >= INDEX_MIPS_REG_S0 && i <= INDEX_MIPS_REG_S7) || |
| (i > INDEX_MIPS_REG_GP && i < INDEX_MIPS_REG_RA)) && |
| (last_frame->context_validity & |
| StackFrameMIPS::RegisterValidFlag(i))) { |
| // If the STACK CFI data doesn't mention some callee-save register, and |
| // it is valid in the callee, assume the callee has not yet changed it. |
| // Calee-save registers according to the MIPS o32 ABI specification are: |
| // $s0 to $s7 |
| // $sp, $s8 |
| frame->context.iregs[i] = last_frame->context.iregs[i]; |
| frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); |
| } |
| } |
| |
| frame->context.epc = caller_registers["$pc"]; |
| frame->instruction = caller_registers["$pc"]; |
| frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; |
| |
| frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = caller_registers["$ra"]; |
| frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; |
| |
| frame->trust = StackFrame::FRAME_TRUST_CFI; |
| |
| return frame.release(); |
| } |
| |
| StackFrame* StackwalkerMIPS::GetCallerFrame(const CallStack* stack, |
| bool stack_scan_allowed) { |
| if (!memory_ || !stack) { |
| BPLOG(ERROR) << "Can't get caller frame without memory or stack"; |
| return NULL; |
| } |
| |
| const vector<StackFrame*>& frames = *stack->frames(); |
| StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); |
| scoped_ptr<StackFrameMIPS> new_frame; |
| |
| // See if there is DWARF call frame information covering this address. |
| scoped_ptr<CFIFrameInfo> cfi_frame_info( |
| frame_symbolizer_->FindCFIFrameInfo(last_frame)); |
| if (cfi_frame_info.get()) |
| new_frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get())); |
| |
| // If caller frame is not found in CFI try analyzing the stack. |
| if (stack_scan_allowed && !new_frame.get()) { |
| new_frame.reset(GetCallerByStackScan(frames)); |
| } |
| |
| // If nothing worked, tell the caller. |
| if (!new_frame.get()) { |
| return NULL; |
| } |
| |
| // Treat an instruction address of 0 as end-of-stack. |
| if (new_frame->context.epc == 0) { |
| return NULL; |
| } |
| |
| // If the new stack pointer is at a lower address than the old, then |
| // that's clearly incorrect. Treat this as end-of-stack to enforce |
| // progress and avoid infinite loops. |
| if (new_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP] <= |
| last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP]) { |
| return NULL; |
| } |
| |
| return new_frame.release(); |
| } |
| |
| StackFrameMIPS* StackwalkerMIPS::GetCallerByStackScan( |
| const vector<StackFrame*>& frames) { |
| const uint32_t kMaxFrameStackSize = 1024; |
| const uint32_t kMinArgsOnStack = 4; |
| |
| StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); |
| |
| uint32_t last_sp = last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP]; |
| uint32_t caller_pc, caller_sp, caller_fp; |
| |
| // Return address cannot be obtained directly. |
| // Force stackwalking. |
| |
| // We cannot use frame pointer to get the return address. |
| // We'll scan the stack for a |
| // return address. This can happen if last_frame is executing code |
| // for a module for which we don't have symbols. |
| int count = kMaxFrameStackSize / sizeof(caller_pc); |
| |
| if (frames.size() > 1) { |
| // In case of mips32 ABI stack frame of a nonleaf function |
| // must have minimum stack frame assigned for 4 arguments (4 words). |
| // Move stack pointer for 4 words to avoid reporting non-existing frames |
| // for all frames except the topmost one. |
| // There is no way of knowing if topmost frame belongs to a leaf or |
| // a nonleaf function. |
| last_sp += kMinArgsOnStack * sizeof(caller_pc); |
| // Adjust 'count' so that return address is scanned only in limits |
| // of one stack frame. |
| count -= kMinArgsOnStack; |
| } |
| |
| do { |
| // Scanning for return address from stack pointer of the last frame. |
| if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc, count)) { |
| // If we can't find an instruction pointer even with stack scanning, |
| // give up. |
| BPLOG(ERROR) << " ScanForReturnAddress failed "; |
| return NULL; |
| } |
| // Get $fp stored in the stack frame. |
| if (!memory_->GetMemoryAtAddress(caller_sp - sizeof(caller_pc), |
| &caller_fp)) { |
| BPLOG(INFO) << " GetMemoryAtAddress for fp failed " ; |
| return NULL; |
| } |
| |
| count = count - (caller_sp - last_sp) / sizeof(caller_pc); |
| // Now scan the next address in the stack. |
| last_sp = caller_sp + sizeof(caller_pc); |
| } while ((caller_fp - caller_sp >= kMaxFrameStackSize) && count > 0); |
| |
| if (!count) { |
| BPLOG(INFO) << " No frame found " ; |
| return NULL; |
| } |
| |
| // ScanForReturnAddress found a reasonable return address. Advance |
| // $sp to the location above the one where the return address was |
| // found. |
| caller_sp += sizeof(caller_pc); |
| // caller_pc is actually containing $ra value; |
| // $pc is two instructions before $ra, |
| // so the caller_pc needs to be decremented accordingly. |
| caller_pc -= 2 * sizeof(caller_pc); |
| |
| |
| // Create a new stack frame (ownership will be transferred to the caller) |
| // and fill it in. |
| StackFrameMIPS* frame = new StackFrameMIPS(); |
| frame->trust = StackFrame::FRAME_TRUST_SCAN; |
| frame->context = last_frame->context; |
| frame->context.epc = caller_pc; |
| frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; |
| frame->instruction = caller_pc; |
| |
| frame->context.iregs[MD_CONTEXT_MIPS_REG_SP] = caller_sp; |
| frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_SP; |
| frame->context.iregs[MD_CONTEXT_MIPS_REG_FP] = caller_fp; |
| frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_FP; |
| |
| frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = |
| caller_pc + 2 * sizeof(caller_pc); |
| frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; |
| |
| return frame; |
| } |
| |
| } // namespace google_breakpad |
| |