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Diffstat (limited to 'src/processor/stackwalker_mips.cc')
| -rw-r--r-- | src/processor/stackwalker_mips.cc | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/src/processor/stackwalker_mips.cc b/src/processor/stackwalker_mips.cc new file mode 100644 index 00000000..74f7f57d --- /dev/null +++ b/src/processor/stackwalker_mips.cc @@ -0,0 +1,300 @@ +// 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 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// 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()); + + unsigned long 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 + |