Index: kernel/arch/amd64/include/istate.h
===================================================================
--- kernel/arch/amd64/include/istate.h	(revision 0fa34dda5c55295515ecd984f5b5364c4e1d0206)
+++ kernel/arch/amd64/include/istate.h	(revision d59c04658e0199d07b5c3ae2ee72998bdb6b8ee9)
@@ -66,8 +66,10 @@
 } istate_t;
 
+#define RPL_USER	3
+
 /** Return true if exception happened while in userspace */
 NO_TRACE static inline int istate_from_uspace(istate_t *istate)
 {
-	return !(istate->rip & UINT64_C(0x8000000000000000));
+	return (istate->cs & RPL_USER) == RPL_USER;
 }