3 files changed, 13 insertions, 2 deletions
diff --git a/src/arch/x86/faults.cc b/src/arch/x86/faults.cc
index 4c8fb33c2..4f2d97f90 100644
--- a/src/arch/x86/faults.cc
+++ b/src/arch/x86/faults.cc
@@ -270,6 +270,13 @@ namespace X86ISA
 #else
 
     void
+    InvalidOpcode::invoke(ThreadContext * tc, StaticInstPtr inst)
+    {
+        panic("Unrecognized/invalid instruction executed:\n %s",
+                inst->machInst);
+    }
+
+    void
     PageFault::invoke(ThreadContext * tc, StaticInstPtr inst)
     {
         PageFaultErrorCode code = errorCode;
diff --git a/src/arch/x86/faults.hh b/src/arch/x86/faults.hh
index f98ef72e9..cfb654b62 100644
--- a/src/arch/x86/faults.hh
+++ b/src/arch/x86/faults.hh
@@ -250,6 +250,11 @@ namespace X86ISA
         InvalidOpcode() :
             X86Fault("Invalid-Opcode", "#UD", 6)
         {}
+
+#if !FULL_SYSTEM
+        void invoke(ThreadContext * tc,
+                StaticInstPtr inst = StaticInst::nullStaticInstPtr);
+#endif
     };
 
     class DeviceNotAvailable : public X86Fault
diff --git a/src/arch/x86/isa/formats/unknown.isa b/src/arch/x86/isa/formats/unknown.isa
index 9b283b5d7..11751e861 100644
--- a/src/arch/x86/isa/formats/unknown.isa
+++ b/src/arch/x86/isa/formats/unknown.isa
@@ -77,8 +77,7 @@ output exec {{
         Fault Unknown::execute(%(CPU_exec_context)s *xc,
                 Trace::InstRecord *traceData) const
         {
-            warn("No instructions are implemented for X86!\n");
-            return NoFault;
+            return new InvalidOpcode();
         }
 }};