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diff --git a/src/processor/stackwalker_ppc64.cc b/src/processor/stackwalker_ppc64.cc
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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_ppc64.cc: ppc64-specific stackwalker.
+//
+// See stackwalker_ppc64.h for documentation.
+
+
+#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) {
+  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;
+  }
+
+  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;
+
+  // 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;
+}
+
+
+}  // namespace google_breakpad