diff --git a/ntoskrnl/include/internal/ke.h b/ntoskrnl/include/internal/ke.h
index 7bdd97fd8ee..f4a8289155e 100644
--- a/ntoskrnl/include/internal/ke.h
+++ b/ntoskrnl/include/internal/ke.h
@@ -1015,8 +1015,8 @@ KiQuantumEnd(
     VOID
 );
 
+DECLSPEC_NORETURN
 VOID
-FASTCALL
 KiIdleLoop(
     VOID
 );
diff --git a/ntoskrnl/ke/amd64/stubs.c b/ntoskrnl/ke/amd64/stubs.c
index 08076199d56..1afc1f54dea 100644
--- a/ntoskrnl/ke/amd64/stubs.c
+++ b/ntoskrnl/ke/amd64/stubs.c
@@ -167,8 +167,8 @@ KiSwitchKernelStack(PVOID StackBase, PVOID StackLimit)
     return OldStackBase;
 }
 
+DECLSPEC_NORETURN
 VOID
-FASTCALL
 KiIdleLoop(VOID)
 {
     PKPRCB Prcb = KeGetCurrentPrcb();
diff --git a/ntoskrnl/ke/arm/thrdini.c b/ntoskrnl/ke/arm/thrdini.c
index f8326724e57..e2833c6f808 100644
--- a/ntoskrnl/ke/arm/thrdini.c
+++ b/ntoskrnl/ke/arm/thrdini.c
@@ -148,8 +148,8 @@ KiInitializeContextThread(IN PKTHREAD Thread,
     Thread->KernelStack = (PVOID)CtxSwitchFrame;
 }
 
+DECLSPEC_NORETURN
 VOID
-FASTCALL
 KiIdleLoop(VOID)
 {
     PKPRCB Prcb = KeGetCurrentPrcb();
diff --git a/ntoskrnl/ke/arm/trapc.c b/ntoskrnl/ke/arm/trapc.c
index 0f94c17ea95..020ec8db7f2 100644
--- a/ntoskrnl/ke/arm/trapc.c
+++ b/ntoskrnl/ke/arm/trapc.c
@@ -15,6 +15,7 @@
 /* FUNCTIONS ******************************************************************/
 
 #if 0
+DECLSPEC_NORETURN
 VOID
 KiIdleLoop(VOID)
 {
diff --git a/ntoskrnl/ke/i386/thrdini.c b/ntoskrnl/ke/i386/thrdini.c
index 7ce51632af2..bb90f78cadf 100644
--- a/ntoskrnl/ke/i386/thrdini.c
+++ b/ntoskrnl/ke/i386/thrdini.c
@@ -266,8 +266,8 @@ KiInitializeContextThread(IN PKTHREAD Thread,
     Thread->KernelStack = (PVOID)CtxSwitchFrame;
 }
 
+DECLSPEC_NORETURN
 VOID
-FASTCALL
 KiIdleLoop(VOID)
 {
     PKPRCB Prcb = KeGetCurrentPrcb();