--- a/hotspot/src/cpu/x86/vm/stubGenerator_x86_64.cpp	Wed May 04 17:47:05 2016 +0300
+++ b/hotspot/src/cpu/x86/vm/stubGenerator_x86_64.cpp	Wed May 04 15:32:26 2016 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -61,6 +61,21 @@
 
 // Stub Code definitions
 
+static address handle_unsafe_access() {
+  JavaThread* thread = JavaThread::current();
+  address pc = thread->saved_exception_pc();
+  // pc is the instruction which we must emulate
+  // doing a no-op is fine:  return garbage from the load
+  // therefore, compute npc
+  address npc = Assembler::locate_next_instruction(pc);
+
+  // request an async exception
+  thread->set_pending_unsafe_access_error();
+
+  // return address of next instruction to execute
+  return npc;
+}
+
 class StubGenerator: public StubCodeGenerator {
  private:
 
@@ -974,6 +989,32 @@
     return start;
   }
 
+  // The following routine generates a subroutine to throw an
+  // asynchronous UnknownError when an unsafe access gets a fault that
+  // could not be reasonably prevented by the programmer.  (Example:
+  // SIGBUS/OBJERR.)
+  address generate_handler_for_unsafe_access() {
+    StubCodeMark mark(this, "StubRoutines", "handler_for_unsafe_access");
+    address start = __ pc();
+
+    __ push(0);                       // hole for return address-to-be
+    __ pusha();                       // push registers
+    Address next_pc(rsp, RegisterImpl::number_of_registers * BytesPerWord);
+
+    // FIXME: this probably needs alignment logic
+
+    __ subptr(rsp, frame::arg_reg_save_area_bytes);
+    BLOCK_COMMENT("call handle_unsafe_access");
+    __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, handle_unsafe_access)));
+    __ addptr(rsp, frame::arg_reg_save_area_bytes);
+
+    __ movptr(next_pc, rax);          // stuff next address
+    __ popa();
+    __ ret(0);                        // jump to next address
+
+    return start;
+  }
+
   // Non-destructive plausibility checks for oops
   //
   // Arguments:
@@ -5095,6 +5136,9 @@
     StubRoutines::_atomic_add_ptr_entry      = generate_atomic_add_ptr();
     StubRoutines::_fence_entry               = generate_orderaccess_fence();
 
+    StubRoutines::_handler_for_unsafe_access_entry =
+      generate_handler_for_unsafe_access();
+
     // platform dependent
     StubRoutines::x86::_get_previous_fp_entry = generate_get_previous_fp();
     StubRoutines::x86::_get_previous_sp_entry = generate_get_previous_sp();