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// 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_) {
if (context_->context_flags & MD_CONTEXT_MIPS64 ) {
if (0xffffffffffffffff - memory_->GetBase() < memory_->GetSize() - 1) {
BPLOG(ERROR) << "Memory out of range for stackwalking mips64: "
<< HexString(memory_->GetBase())
<< "+"
<< HexString(memory_->GetSize());
memory_ = NULL;
}
} else {
if (0xffffffff - memory_->GetBase() < memory_->GetSize() - 1) {
BPLOG(ERROR) << "Memory out of range for stackwalking mips32: "
<< 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());
if (context_->context_flags & MD_CONTEXT_MIPS) {
uint32_t 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()) {
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();
} else {
uint64_t pc = 0;
// Populate a dictionary with the valid register values in last_frame.
CFIFrameInfo::RegisterValueMap<uint64_t> callee_registers;
// Use the STACK CFI data to recover the caller's register values.
CFIFrameInfo::RegisterValueMap<uint64_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<uint64_t>::const_iterator entry =
caller_registers.find(".cfa");
if (entry != caller_registers.end()) {
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<uint64_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;
}
// Should we terminate the stack walk? (end-of-stack or broken invariant)
if (TerminateWalk(new_frame->context.epc,
new_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP],
last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP],
frames.size() == 1)) {
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());
if (context_->context_flags & MD_CONTEXT_MIPS) {
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;
} else {
uint64_t last_sp = last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP];
uint64_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);
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