Syscall: Make the syscall function available in both SE and FS modes.

In FS mode the syscall function will panic, but the interface will be
consistent and code which calls syscall can be compiled in. This will allow,
for instance, instructions that use syscall to be built unconditionally but
then not returned by the decoder.

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)

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

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

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
+}
 

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; }
 };