diff --git a/src/cpu/inorder/inorder_dyn_inst.cc b/src/cpu/inorder/inorder_dyn_inst.cc
index f65d2ea9fd..ff178f6d3e 100644
--- a/src/cpu/inorder/inorder_dyn_inst.cc
+++ b/src/cpu/inorder/inorder_dyn_inst.cc
@@ -311,14 +311,18 @@ InOrderDynInst::simPalCheck(int palFunc)
 #endif
     return this->cpu->simPalCheck(palFunc, this->threadNumber);
 }
-#else
+#endif
+
 void
 InOrderDynInst::syscall(int64_t callnum)
 {
+#if FULL_SYSTEM
+    panic("Syscall emulation isn't available in FS mode.\n");
+#else
     syscallNum = callnum;
     cpu->syscallContext(NoFault, this->threadNumber, this);
-}
 #endif
+}
 
 void
 InOrderDynInst::setSquashInfo(unsigned stage_num)
diff --git a/src/cpu/inorder/inorder_dyn_inst.hh b/src/cpu/inorder/inorder_dyn_inst.hh
index 3427af86b2..f49476ec59 100644
--- a/src/cpu/inorder/inorder_dyn_inst.hh
+++ b/src/cpu/inorder/inorder_dyn_inst.hh
@@ -525,11 +525,11 @@ class InOrderDynInst : public FastAlloc, public RefCounted
     bool simPalCheck(int palFunc);
 #else
     short syscallNum;
-
-    /** Calls a syscall. */
-    void syscall(int64_t callnum);
 #endif
 
+    /** Emulates a syscall. */
+    void syscall(int64_t callnum);
+
     ////////////////////////////////////////////////////////////
     //
     // MULTITHREADING INTERFACE TO CPU MODELS
diff --git a/src/cpu/o3/dyn_inst.hh b/src/cpu/o3/dyn_inst.hh
index 399240d69a..e58eb99c5f 100644
--- a/src/cpu/o3/dyn_inst.hh
+++ b/src/cpu/o3/dyn_inst.hh
@@ -205,11 +205,11 @@ class BaseO3DynInst : public BaseDynInst<Impl>
     /** Traps to handle specified fault. */
     void trap(Fault fault);
     bool simPalCheck(int palFunc);
-#else
-    /** Calls a syscall. */
-    void syscall(int64_t callnum);
 #endif
 
+    /** Emulates a syscall. */
+    void syscall(int64_t callnum);
+
   public:
 
     // The register accessor methods provide the index of the
diff --git a/src/cpu/o3/dyn_inst_impl.hh b/src/cpu/o3/dyn_inst_impl.hh
index eceb0b49f9..500d63de88 100644
--- a/src/cpu/o3/dyn_inst_impl.hh
+++ b/src/cpu/o3/dyn_inst_impl.hh
@@ -188,11 +188,15 @@ BaseO3DynInst<Impl>::simPalCheck(int palFunc)
 #endif
     return this->cpu->simPalCheck(palFunc, this->threadNumber);
 }
-#else
+#endif
+
 template <class Impl>
 void
 BaseO3DynInst<Impl>::syscall(int64_t callnum)
 {
+#if FULL_SYSTEM
+    panic("Syscall emulation isn't available in FS mode.\n");
+#else
     // HACK: check CPU's nextPC before and after syscall. If it
     // changes, update this instruction's nextPC because the syscall
     // must have changed the nextPC.
@@ -202,6 +206,6 @@ BaseO3DynInst<Impl>::syscall(int64_t callnum)
     if (!(curPC == newPC)) {
         this->pcState(newPC);
     }
-}
 #endif
+}
 
diff --git a/src/cpu/simple/base.hh b/src/cpu/simple/base.hh
index b27ebf9984..ad281aa2b8 100644
--- a/src/cpu/simple/base.hh
+++ b/src/cpu/simple/base.hh
@@ -402,10 +402,18 @@ class BaseSimpleCPU : public BaseCPU
 #if FULL_SYSTEM
     Fault hwrei() { return thread->hwrei(); }
     bool simPalCheck(int palFunc) { return thread->simPalCheck(palFunc); }
-#else
-    void syscall(int64_t callnum) { thread->syscall(callnum); }
 #endif
 
+    void
+    syscall(int64_t callnum)
+    {
+#if FULL_SYSTEM
+        panic("Syscall emulation isn't available in FS mode.\n");
+#else
+        thread->syscall(callnum);
+#endif
+    }
+
     bool misspeculating() { return thread->misspeculating(); }
     ThreadContext *tcBase() { return tc; }
 };