diff --git a/src/driver/fortcout.c b/src/driver/fortcout.c
index 990cff58..78f4ca3a 100644
--- a/src/driver/fortcout.c
+++ b/src/driver/fortcout.c
@@ -745,7 +745,7 @@ FORT_API NTSTATUS fort_callout_force_reauth(
     return status;
 }
 
-FORT_API void fort_callout_timer(void)
+FORT_API void NTAPI fort_callout_timer(void)
 {
     PFORT_BUFFER buf = &fort_device()->buffer;
     PFORT_STAT stat = &fort_device()->stat;
diff --git a/src/driver/fortcout.h b/src/driver/fortcout.h
index 33ce3c04..1213f932 100644
--- a/src/driver/fortcout.h
+++ b/src/driver/fortcout.h
@@ -18,7 +18,7 @@ FORT_API void fort_callout_remove(void);
 FORT_API NTSTATUS fort_callout_force_reauth(
         const FORT_CONF_FLAGS old_conf_flags, UINT32 defer_flush_bits);
 
-FORT_API void fort_callout_timer(void);
+FORT_API void NTAPI fort_callout_timer(void);
 
 #ifdef __cplusplus
 } // extern "C"
diff --git a/src/driver/fortdev.c b/src/driver/fortdev.c
index 2838a9d0..b65c45ec 100644
--- a/src/driver/fortdev.c
+++ b/src/driver/fortdev.c
@@ -35,7 +35,7 @@ static void fort_worker_reauth(void)
     }
 }
 
-FORT_API void fort_app_period_timer(void)
+FORT_API void NTAPI fort_app_period_timer(void)
 {
     if (fort_conf_ref_period_update(&g_device->conf, FALSE, NULL)) {
         fort_worker_queue(&g_device->worker, FORT_WORKER_REAUTH, &fort_worker_reauth);
diff --git a/src/driver/fortdev.h b/src/driver/fortdev.h
index 98949556..f377c0dd 100644
--- a/src/driver/fortdev.h
+++ b/src/driver/fortdev.h
@@ -36,7 +36,7 @@ extern "C" {
 
 FORT_API PFORT_DEVICE fort_device();
 
-FORT_API void fort_app_period_timer(void);
+FORT_API void NTAPI fort_app_period_timer(void);
 
 FORT_API NTSTATUS fort_device_create(PDEVICE_OBJECT device, PIRP irp);
 
diff --git a/src/driver/fortscb.c b/src/driver/fortscb.c
index e8734ad0..030d4b6a 100644
--- a/src/driver/fortscb.c
+++ b/src/driver/fortscb.c
@@ -37,7 +37,7 @@ static void fort_syscb_unregister(PCALLBACK_OBJECT cb_obj, PVOID cb_reg)
     }
 }
 
-static void fort_syscb_power(PVOID context, PVOID event, PVOID specifics)
+static void NTAPI fort_syscb_power(PVOID context, PVOID event, PVOID specifics)
 {
     UNUSED(context);
 
@@ -65,7 +65,7 @@ FORT_API void fort_syscb_power_unregister(void)
     fort_syscb_unregister(fort_device()->power_cb_obj, fort_device()->power_cb_reg);
 }
 
-static void fort_syscb_time(PVOID context, PVOID event, PVOID specifics)
+static void NTAPI fort_syscb_time(PVOID context, PVOID event, PVOID specifics)
 {
     UNUSED(context);
     UNUSED(event);
diff --git a/src/driver/forttmr.c b/src/driver/forttmr.c
index df590181..58793d56 100644
--- a/src/driver/forttmr.c
+++ b/src/driver/forttmr.c
@@ -4,7 +4,7 @@
 
 #include "fortcb.h"
 
-static void fort_timer_callback(PKDPC dpc, PFORT_TIMER timer, PVOID arg1, PVOID arg2)
+static void NTAPI fort_timer_callback(PKDPC dpc, PFORT_TIMER timer, PVOID arg1, PVOID arg2)
 {
     UNUSED(dpc);
     UNUSED(arg1);
diff --git a/src/driver/fortwrk.c b/src/driver/fortwrk.c
index 90440cea..4d5cfe92 100644
--- a/src/driver/fortwrk.c
+++ b/src/driver/fortwrk.c
@@ -4,7 +4,7 @@
 
 #include "fortcb.h"
 
-static void fort_worker_callback(PVOID device, PVOID context, PIO_WORKITEM item)
+static void NTAPI fort_worker_callback(PVOID device, PVOID context, PIO_WORKITEM item)
 {
     PFORT_WORKER worker = (PFORT_WORKER) context;
     const UCHAR id_bits = InterlockedAnd8(&worker->id_bits, 0);