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// Copyright (c) 2010 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_amd64.cc: amd64-specific stackwalker.
//
// See stackwalker_amd64.h for documentation.
//
// Author: Mark Mentovai, Ted Mielczarek
#include "google_breakpad/processor/call_stack.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/scoped_ptr.h"
#include "processor/stackwalker_amd64.h"
namespace google_breakpad {
const StackwalkerAMD64::CFIWalker::RegisterSet
StackwalkerAMD64::cfi_register_map_[] = {
// It may seem like $rip and $rsp are callee-saves, because the callee is
// responsible for having them restored upon return. But the callee_saves
// flags here really means that the walker should assume they're
// unchanged if the CFI doesn't mention them --- clearly wrong for $rip
// and $rsp.
{ "$rax", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RAX, &MDRawContextAMD64::rax },
{ "$rdx", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RDX, &MDRawContextAMD64::rdx },
{ "$rcx", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RCX, &MDRawContextAMD64::rcx },
{ "$rbx", NULL, true,
StackFrameAMD64::CONTEXT_VALID_RBX, &MDRawContextAMD64::rbx },
{ "$rsi", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RSI, &MDRawContextAMD64::rsi },
{ "$rdi", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RDI, &MDRawContextAMD64::rdi },
{ "$rbp", NULL, true,
StackFrameAMD64::CONTEXT_VALID_RBP, &MDRawContextAMD64::rbp },
{ "$rsp", ".cfa", false,
StackFrameAMD64::CONTEXT_VALID_RSP, &MDRawContextAMD64::rsp },
{ "$r8", NULL, false,
StackFrameAMD64::CONTEXT_VALID_R8, &MDRawContextAMD64::r8 },
{ "$r9", NULL, false,
StackFrameAMD64::CONTEXT_VALID_R9, &MDRawContextAMD64::r9 },
{ "$r10", NULL, false,
StackFrameAMD64::CONTEXT_VALID_R10, &MDRawContextAMD64::r10 },
{ "$r11", NULL, false,
StackFrameAMD64::CONTEXT_VALID_R11, &MDRawContextAMD64::r11 },
{ "$r12", NULL, true,
StackFrameAMD64::CONTEXT_VALID_R12, &MDRawContextAMD64::r12 },
{ "$r13", NULL, true,
StackFrameAMD64::CONTEXT_VALID_R13, &MDRawContextAMD64::r13 },
{ "$r14", NULL, true,
StackFrameAMD64::CONTEXT_VALID_R14, &MDRawContextAMD64::r14 },
{ "$r15", NULL, true,
StackFrameAMD64::CONTEXT_VALID_R15, &MDRawContextAMD64::r15 },
{ "$rip", ".ra", false,
StackFrameAMD64::CONTEXT_VALID_RIP, &MDRawContextAMD64::rip },
};
StackwalkerAMD64::StackwalkerAMD64(const SystemInfo *system_info,
const MDRawContextAMD64 *context,
MemoryRegion *memory,
const CodeModules *modules,
SymbolSupplier *supplier,
SourceLineResolverInterface *resolver)
: Stackwalker(system_info, memory, modules, supplier, resolver),
context_(context),
cfi_walker_(cfi_register_map_,
(sizeof(cfi_register_map_) / sizeof(cfi_register_map_[0]))) {
}
StackFrame* StackwalkerAMD64::GetContextFrame() {
if (!context_ || !memory_) {
BPLOG(ERROR) << "Can't get context frame without context or memory";
return NULL;
}
StackFrameAMD64 *frame = new StackFrameAMD64();
// 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 = StackFrameAMD64::CONTEXT_VALID_ALL;
frame->instruction = frame->context.rip;
return frame;
}
StackFrameAMD64 *StackwalkerAMD64::GetCallerByCFIFrameInfo(
const vector<StackFrame *> &frames,
CFIFrameInfo *cfi_frame_info) {
StackFrameAMD64 *last_frame = static_cast<StackFrameAMD64*>(frames.back());
scoped_ptr<StackFrameAMD64> frame(new StackFrameAMD64());
if (!cfi_walker_
.FindCallerRegisters(*memory_, *cfi_frame_info,
last_frame->context, last_frame->context_validity,
&frame->context, &frame->context_validity))
return NULL;
// Make sure we recovered all the essentials.
static const int essentials = (StackFrameAMD64::CONTEXT_VALID_RIP
| StackFrameAMD64::CONTEXT_VALID_RSP);
if ((frame->context_validity & essentials) != essentials)
return NULL;
return frame.release();
}
StackFrame* StackwalkerAMD64::GetCallerFrame(const CallStack *stack) {
if (!memory_ || !stack) {
BPLOG(ERROR) << "Can't get caller frame without memory or stack";
return NULL;
}
const vector<StackFrame *> &frames = *stack->frames();
StackFrameAMD64 *last_frame = static_cast<StackFrameAMD64 *>(frames.back());
scoped_ptr<StackFrameAMD64> new_frame;
// If we have DWARF CFI information, use it.
scoped_ptr<CFIFrameInfo> cfi_frame_info(
resolver_->FindCFIFrameInfo(last_frame));
if (cfi_frame_info.get())
new_frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get()));
// 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.rip == 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.rsp <= last_frame->context.rsp)
return NULL;
// new_frame->context.rip is the return address, which is one instruction
// past the CALL that caused us to arrive at the callee. Set
// new_frame->instruction to one less than that. This won't reference the
// beginning of the CALL instruction, but it's guaranteed to be within
// the CALL, which is sufficient to get the source line information to
// match up with the line that contains a function call. Callers that
// require the exact return address value may access the context.rip
// field of StackFrameAMD64.
new_frame->instruction = new_frame->context.rip - 1;
return new_frame.release();
}
} // namespace google_breakpad
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