// 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_ppc64.cc: ppc64-specific stackwalker. // // See stackwalker_ppc64.h for documentation. #include "common/scoped_ptr.h" #include "processor/stackwalker_ppc64.h" #include "google_breakpad/processor/call_stack.h" #include "google_breakpad/processor/memory_region.h" #include "google_breakpad/processor/stack_frame_cpu.h" #include "processor/logging.h" #include <stdio.h> namespace google_breakpad { StackwalkerPPC64::StackwalkerPPC64(const SystemInfo* system_info, const MDRawContextPPC64* context, MemoryRegion* memory, const CodeModules* modules, StackFrameSymbolizer* resolver_helper) : Stackwalker(system_info, memory, modules, resolver_helper), context_(context) { } StackFrame* StackwalkerPPC64::GetContextFrame() { if (!context_) { BPLOG(ERROR) << "Can't get context frame without context"; return NULL; } StackFramePPC64* frame = new StackFramePPC64(); // 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 = StackFramePPC64::CONTEXT_VALID_ALL; frame->trust = StackFrame::FRAME_TRUST_CONTEXT; frame->instruction = frame->context.srr0; return frame; } StackFrame* StackwalkerPPC64::GetCallerFrame(const CallStack* stack, bool stack_scan_allowed) { if (!memory_ || !stack) { BPLOG(ERROR) << "Can't get caller frame without memory or stack"; return NULL; } // The instruction pointers for previous frames are saved on the stack. // The typical ppc64 calling convention is for the called procedure to store // its return address in the calling procedure's stack frame at 8(%r1), // and to allocate its own stack frame by decrementing %r1 (the stack // pointer) and saving the old value of %r1 at 0(%r1). Because the ppc64 has // no hardware stack, there is no distinction between the stack pointer and // frame pointer, and what is typically thought of as the frame pointer on // an x86 is usually referred to as the stack pointer on a ppc64. StackFramePPC64* last_frame = static_cast<StackFramePPC64*>( stack->frames()->back()); // A caller frame must reside higher in memory than its callee frames. // Anything else is an error, or an indication that we've reached the // end of the stack. uint64_t stack_pointer; if (!memory_->GetMemoryAtAddress(last_frame->context.gpr[1], &stack_pointer) || stack_pointer <= last_frame->context.gpr[1]) { return NULL; } // Mac OS X/Darwin gives 1 as the return address from the bottom-most // frame in a stack (a thread's entry point). I haven't found any // documentation on this, but 0 or 1 would be bogus return addresses, // so check for them here and return false (end of stack) when they're // hit to avoid having a phantom frame. uint64_t instruction; if (!memory_->GetMemoryAtAddress(stack_pointer + 16, &instruction) || instruction <= 1) { return NULL; } scoped_ptr<StackFramePPC64> frame(new StackFramePPC64()); frame->context = last_frame->context; frame->context.srr0 = instruction; frame->context.gpr[1] = stack_pointer; frame->context_validity = StackFramePPC64::CONTEXT_VALID_SRR0 | StackFramePPC64::CONTEXT_VALID_GPR1; frame->trust = StackFrame::FRAME_TRUST_FP; // Should we terminate the stack walk? (end-of-stack or broken invariant) if (TerminateWalk(instruction, stack_pointer, last_frame->context.gpr[1], stack->frames()->size() == 1)) { return NULL; } // frame->context.srr0 is the return address, which is one instruction // past the branch that caused us to arrive at the callee. Set // frame_ppc64->instruction to eight less than that. Since all ppc64 // instructions are 8 bytes wide, this is the address of the branch // instruction. This allows 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.srr0 field of StackFramePPC64. frame->instruction = frame->context.srr0 - 8; return frame.release(); } } // namespace google_breakpad