Wire thread startup frame to return to user-mode switch or system thread exit handler

xtoskrnl/includes/ke/kthread.hh

@@ -38,6 +38,7 @@ namespace KE
             STATIC XTAPI VOID StartThread(IN PKTHREAD Thread);
 
         private:
+            STATIC XTAPI VOID HandleSystemThreadExit(VOID);
             STATIC XTAPI VOID InitializeThreadContext(IN PKTHREAD Thread,
                                                       IN PKSYSTEM_ROUTINE SystemRoutine,
                                                       IN PKSTART_ROUTINE StartRoutine,
@@ -53,6 +54,7 @@ namespace KE
             STATIC XTAPI VOID SuspendThread(IN PVOID NormalContext,
                                             IN PVOID SystemArgument1,
                                             IN PVOID SystemArgument2);
+            STATIC XTAPI VOID SwitchToUserMode(VOID);
     };
 }
 

xtoskrnl/ke/amd64/kthread.cc

@@ -105,6 +105,9 @@ KE::KThread::InitializeThreadContext(IN PKTHREAD Thread,
         ThreadFrame->ExceptionFrame.P2Home = (ULONGLONG)StartRoutine;
         ThreadFrame->ExceptionFrame.P3Home = (ULONGLONG)SystemRoutine;
         ThreadFrame->ExceptionFrame.P4Home = (ULONGLONG)SystemRoutine;
+
+        /* Set the routine that will handle the thread finishing its initialization and transition it to UserMode */
+        ThreadFrame->StartFrame.Return = (ULONG64)SwitchToUserMode;
     }
     else
     {
@@ -113,6 +116,9 @@ KE::KThread::InitializeThreadContext(IN PKTHREAD Thread,
 
         /* Disable floating point state */
         Thread->NpxState = NPX_STATE_UNUSED;
+
+        /* Set the routine that will handle a system thread that unexpectedly finished its execution */
+        ThreadFrame->StartFrame.Return = (ULONG64)HandleSystemThreadExit;
     }
 
     /* Initialize thread startup information */

xtoskrnl/ke/i686/kthread.cc

@@ -99,6 +99,9 @@ KE::KThread::InitializeThreadContext(IN PKTHREAD Thread,
         ThreadFrame->TrapFrame.SegDs |= RPL_MASK;
         ThreadFrame->TrapFrame.SegEs |= RPL_MASK;
         ThreadFrame->TrapFrame.SegSs |= RPL_MASK;
+
+        /* Set the routine that will handle the thread finishing its initialization and transition it to UserMode */
+        ThreadFrame->StartFrame.Return = (ULONG)SwitchToUserMode;
     }
     else
     {
@@ -112,6 +115,9 @@ KE::KThread::InitializeThreadContext(IN PKTHREAD Thread,
         /* Set initial floating point state */
         ThreadFrame->NpxFrame.FxArea.ControlWord = 0x27F;
         ThreadFrame->NpxFrame.FxArea.MxCsr = 0x1F80;
+
+        /* Set the routine that will handle a system thread that unexpectedly finished its execution */
+        ThreadFrame->StartFrame.Return = (ULONG)HandleSystemThreadExit;
     }
 
     /* Initialize thread startup information */

xtoskrnl/ke/kthread.cc

@@ -23,6 +23,19 @@ KE::KThread::GetInitialThread(VOID)
     return &InitialThread;
 }
 
+/**
+ * Handles an unexpected system thread exit.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+KE::KThread::HandleSystemThreadExit(VOID)
+{
+}
+
 /**
  * Initializes an Idle Thread.
  *
@@ -369,3 +382,16 @@ KE::KThread::SuspendThread(IN PVOID NormalContext,
 {
     UNIMPLEMENTED;
 }
+
+/**
+ * Switches a new thread into User Mode.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+KE::KThread::SwitchToUserMode(VOID)
+{
+}