diff --git a/include/evl/clock.h b/include/evl/clock.h
index 8822ea7afb4ca3..cb1bbf2cc8b19a 100644
--- a/include/evl/clock.h
+++ b/include/evl/clock.h
@@ -14,7 +14,8 @@
 #include <linux/cpumask.h>
 #include <evl/list.h>
 #include <evl/factory.h>
-#include <uapi/evl/clock.h>
+#include <uapi/evl/types.h>
+#include <uapi/evl/clock-abi.h>
 
 #define ONE_BILLION  1000000000
 
diff --git a/include/evl/control.h b/include/evl/control.h
index 5a736ab2e5eabb..dcc90775f0de8c 100644
--- a/include/evl/control.h
+++ b/include/evl/control.h
@@ -10,6 +10,8 @@
 #include <linux/atomic.h>
 #include <linux/notifier.h>
 #include <evl/factory.h>
+#include <uapi/evl/sched-abi.h>
+#include <uapi/evl/control-abi.h>
 
 enum evl_run_states {
 	EVL_STATE_DISABLED,
diff --git a/include/evl/factory.h b/include/evl/factory.h
index 358aac28f5610e..6b7f82de280761 100644
--- a/include/evl/factory.h
+++ b/include/evl/factory.h
@@ -23,7 +23,7 @@
 #include <evl/assert.h>
 #include <evl/file.h>
 #include <uapi/evl/types.h>
-#include <uapi/evl/factory.h>
+#include <uapi/evl/factory-abi.h>
 
 #define element_of(__filp, __type)					\
 	({								\
diff --git a/include/evl/monitor.h b/include/evl/monitor.h
index 441decab3aad77..632f95d4855174 100644
--- a/include/evl/monitor.h
+++ b/include/evl/monitor.h
@@ -7,9 +7,8 @@
 #ifndef _EVL_MONITOR_H
 #define _EVL_MONITOR_H
 
-#include <evl/factory.h>
 #include <evl/thread.h>
-#include <evl/sched.h>
+#include <uapi/evl/monitor-abi.h>
 
 int evl_signal_monitor_targeted(struct evl_thread *target,
 				int monfd);
diff --git a/include/evl/mutex.h b/include/evl/mutex.h
index 8b3287b6953c6a..0313768cdb81a0 100644
--- a/include/evl/mutex.h
+++ b/include/evl/mutex.h
@@ -15,7 +15,6 @@
 #include <evl/timer.h>
 #include <evl/wait.h>
 #include <evl/sched.h>
-#include <uapi/evl/mutex.h>
 
 struct evl_clock;
 struct evl_thread;
@@ -93,6 +92,12 @@ bool evl_requeue_mutex_wait(struct evl_wait_channel *wchan,
 
 void evl_drop_current_ownership(void);
 
+static inline bool
+evl_is_mutex_owner(atomic_t *fastlock, fundle_t ownerh)
+{
+	return evl_get_index(atomic_read(fastlock)) == ownerh;
+}
+
 struct evl_kmutex {
 	struct evl_mutex mutex;
 	atomic_t fastlock;
diff --git a/include/evl/net/socket.h b/include/evl/net/socket.h
index 94bafd0cad7a58..8a62114c0f4bd8 100644
--- a/include/evl/net/socket.h
+++ b/include/evl/net/socket.h
@@ -16,7 +16,9 @@
 #include <evl/file.h>
 #include <evl/poll.h>
 #include <evl/crossing.h>
-#include <uapi/evl/net/socket.h>
+#include <uapi/evl/types.h>
+#include <uapi/evl/fcntl.h>
+#include <uapi/evl/net/socket-abi.h>
 
 struct evl_socket;
 struct net;
diff --git a/include/evl/observable.h b/include/evl/observable.h
index aff0364e439e5e..21f57ab9aa4b96 100644
--- a/include/evl/observable.h
+++ b/include/evl/observable.h
@@ -14,7 +14,8 @@
 #include <evl/factory.h>
 #include <evl/wait.h>
 #include <evl/poll.h>
-#include <uapi/evl/observable.h>
+#include <uapi/evl/types.h>
+#include <uapi/evl/observable-abi.h>
 
 struct file;
 
diff --git a/include/evl/poll.h b/include/evl/poll.h
index efa2b953519716..fba3da8d9373c9 100644
--- a/include/evl/poll.h
+++ b/include/evl/poll.h
@@ -14,7 +14,8 @@
 #include <linux/poll.h>
 #include <evl/wait.h>
 #include <evl/factory.h>
-#include <uapi/evl/poll.h>
+#include <uapi/evl/types.h>
+#include <uapi/evl/poll-abi.h>
 
 struct file;
 
diff --git a/include/evl/thread.h b/include/evl/thread.h
index 2d1d6f8745c096..1c2e4a269ebe39 100644
--- a/include/evl/thread.h
+++ b/include/evl/thread.h
@@ -22,9 +22,9 @@
 #include <evl/sched/param.h>
 #include <evl/factory.h>
 #include <evl/assert.h>
-#include <uapi/evl/thread.h>
+#include <uapi/evl/thread-abi.h>
+#include <uapi/evl/sched-abi.h>
 #include <uapi/evl/signal.h>
-#include <uapi/evl/sched.h>
 #include <asm/evl/thread.h>
 
 /* All bits which may cause an EVL thread to block in oob context. */
diff --git a/include/uapi/evl/clock.h b/include/uapi/evl/clock-abi.h
similarity index 90%
rename from include/uapi/evl/clock.h
rename to include/uapi/evl/clock-abi.h
index 4d3e3ff2ca94f9..1d678d9665a2c7 100644
--- a/include/uapi/evl/clock.h
+++ b/include/uapi/evl/clock-abi.h
@@ -4,10 +4,10 @@
  * Copyright (C) 2018 Philippe Gerum <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_CLOCK_H
-#define _EVL_UAPI_CLOCK_H
+#ifndef _EVL_UAPI_CLOCK_ABI_H
+#define _EVL_UAPI_CLOCK_ABI_H
 
-#include <uapi/evl/types.h>
+#include <linux/types.h>
 
 #define EVL_CLOCK_MONOTONIC_DEV		"monotonic"
 #define EVL_CLOCK_REALTIME_DEV		"realtime"
@@ -34,4 +34,4 @@ struct evl_timerfd_setreq {
 #define EVL_TFDIOC_SET	 _IOWR(EVL_TIMERFD_IOCBASE, 0, struct evl_timerfd_setreq)
 #define EVL_TFDIOC_GET	 _IOR(EVL_TIMERFD_IOCBASE, 1, struct __evl_itimerspec)
 
-#endif /* !_EVL_UAPI_CLOCK_H */
+#endif /* !_EVL_UAPI_CLOCK_ABI_H */
diff --git a/include/uapi/evl/control.h b/include/uapi/evl/control-abi.h
similarity index 89%
rename from include/uapi/evl/control.h
rename to include/uapi/evl/control-abi.h
index 4a33e38e6b9d96..9532d57c04e856 100644
--- a/include/uapi/evl/control.h
+++ b/include/uapi/evl/control-abi.h
@@ -4,11 +4,10 @@
  * Copyright (C) 2018 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_CONTROL_H
-#define _EVL_UAPI_CONTROL_H
+#ifndef _EVL_UAPI_CONTROL_ABI_H
+#define _EVL_UAPI_CONTROL_ABI_H
 
 #include <linux/types.h>
-#include <uapi/evl/sched.h>
 
 /* Earliest ABI level we support. */
 #define EVL_ABI_BASE   23
@@ -40,4 +39,4 @@ struct evl_cpu_state {
 #define EVL_CTLIOC_SCHEDCTL		_IOWR(EVL_CONTROL_IOCBASE, 1, struct evl_sched_ctlreq)
 #define EVL_CTLIOC_GET_CPUSTATE		_IOR(EVL_CONTROL_IOCBASE, 2, struct evl_cpu_state)
 
-#endif /* !_EVL_UAPI_CONTROL_H */
+#endif /* !_EVL_UAPI_CONTROL_ABI_H */
diff --git a/include/uapi/evl/factory.h b/include/uapi/evl/factory-abi.h
similarity index 92%
rename from include/uapi/evl/factory.h
rename to include/uapi/evl/factory-abi.h
index fde46bc92bd559..84e4959103459f 100644
--- a/include/uapi/evl/factory.h
+++ b/include/uapi/evl/factory-abi.h
@@ -4,8 +4,8 @@
  * Copyright (C) 2018 Philippe Gerum <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_FACTORY_H
-#define _EVL_UAPI_FACTORY_H
+#ifndef _EVL_UAPI_FACTORY_ABI_H
+#define _EVL_UAPI_FACTORY_ABI_H
 
 #include <linux/types.h>
 
@@ -45,4 +45,4 @@ struct evl_clone_req {
 
 #define EVL_IOC_CLONE	_IOWR(EVL_FACTORY_IOCBASE, 0, struct evl_clone_req)
 
-#endif /* !_EVL_UAPI_FACTORY_H */
+#endif /* !_EVL_UAPI_FACTORY_ABI_H */
diff --git a/include/uapi/evl/monitor.h b/include/uapi/evl/monitor-abi.h
similarity index 90%
rename from include/uapi/evl/monitor.h
rename to include/uapi/evl/monitor-abi.h
index 434bb089464dce..d77da903816b8c 100644
--- a/include/uapi/evl/monitor.h
+++ b/include/uapi/evl/monitor-abi.h
@@ -4,12 +4,10 @@
  * Copyright (C) 2018 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_MONITOR_H
-#define _EVL_UAPI_MONITOR_H
+#ifndef _EVL_UAPI_MONITOR_ABI_H
+#define _EVL_UAPI_MONITOR_ABI_H
 
-#include <linux/types.h>
-#include <uapi/evl/types.h>
-#include <uapi/evl/factory.h>
+#include <evl/factory-abi.h>
 
 #define EVL_MONITOR_DEV		"monitor"
 
@@ -39,14 +37,14 @@ struct evl_monitor_state {
 	__u32 flags;
 	union {
 		struct {
-			atomic_t owner;
+			__u32 owner; /* atomic_t */
 			__u32 ceiling;
 			__u32 recursive: 1,
 				nesting : 31;
 		} gate;
 		struct {
-			atomic_t value;
-			atomic_t pollrefs;
+			__u32 value; /* atomic_t */
+			__u32 pollrefs; /* atomic_t */
 			__u32 gate_offset;
 		} event;
 	} u;
@@ -87,4 +85,4 @@ struct evl_monitor_binding {
 #define EVL_MONIOC_TRYWAIT		_IOWR(EVL_MONITOR_IOCBASE, 9, struct evl_monitor_trywaitreq)
 #define EVL_MONIOC_TRYWAIT_EXACT	_IOWR(EVL_MONITOR_IOCBASE, 10, struct evl_monitor_trywaitreq)
 
-#endif /* !_EVL_UAPI_MONITOR_H */
+#endif /* !_EVL_UAPI_MONITOR_ABI_H */
diff --git a/include/uapi/evl/mutex.h b/include/uapi/evl/mutex.h
deleted file mode 100644
index 9a1979483313de..00000000000000
--- a/include/uapi/evl/mutex.h
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
- *
- * Derived from Xenomai Cobalt, https://xenomai.org/
- * Copyright (C) 2001, 2013, 2018 Philippe Gerum <rpm@xenomai.org>
- * Copyright (C) 2008, 2009 Jan Kiszka <jan.kiszka@siemens.com>.
- */
-
-#ifndef _EVL_UAPI_MUTEX_H
-#define _EVL_UAPI_MUTEX_H
-
-#include <uapi/evl/types.h>
-
-static inline int
-evl_is_mutex_owner(atomic_t *fastlock, fundle_t ownerh)
-{
-	return evl_get_index(atomic_read(fastlock)) == ownerh;
-}
-
-static inline
-int evl_fast_lock_mutex(atomic_t *fastlock, fundle_t new_ownerh)
-{
-	fundle_t h;
-
-	h = atomic_cmpxchg(fastlock, EVL_NO_HANDLE, new_ownerh);
-	if (h != EVL_NO_HANDLE) {
-		if (evl_get_index(h) == new_ownerh)
-			return -EBUSY;
-
-		return -EAGAIN;
-	}
-
-	return 0;
-}
-
-static inline
-int evl_fast_unlock_mutex(atomic_t *fastlock, fundle_t cur_ownerh)
-{
-	return (fundle_t)atomic_cmpxchg(fastlock, cur_ownerh, EVL_NO_HANDLE)
-		== cur_ownerh;
-}
-
-#endif /* !_EVL_UAPI_MUTEX_H */
diff --git a/include/uapi/evl/net/sched.h b/include/uapi/evl/net/sched.h
deleted file mode 100644
index 583103d5a405a7..00000000000000
--- a/include/uapi/evl/net/sched.h
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
- * SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
- *
- * Copyright (C) 2020 Philippe Gerum  <rpm@xenomai.org>
- */
-
-#ifndef _EVL_UAPI_NET_SCHED_H
-#define _EVL_UAPI_NET_SCHED_H
-
-#endif /* !_EVL_UAPI_NET_SCHED_H */
diff --git a/include/uapi/evl/net/socket.h b/include/uapi/evl/net/socket-abi.h
similarity index 88%
rename from include/uapi/evl/net/socket.h
rename to include/uapi/evl/net/socket-abi.h
index aee01982c11dfe..4973e7d0daee2f 100644
--- a/include/uapi/evl/net/socket.h
+++ b/include/uapi/evl/net/socket-abi.h
@@ -4,11 +4,10 @@
  * Copyright (C) 2020 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_NET_SOCKET_H
-#define _EVL_UAPI_NET_SOCKET_H
+#ifndef _EVL_UAPI_NET_SOCKET_ABI_H
+#define _EVL_UAPI_NET_SOCKET_ABI_H
 
-#include <uapi/evl/types.h>
-#include <uapi/evl/fcntl.h>
+#include <evl/types.h>
 
 #define AF_OOB		46	/* Out-of-band domain sockets */
 
@@ -42,4 +41,4 @@ struct evl_netdev_activation {
 #define EVL_SOCKIOC_SETRECVSZ	_IOW(EVL_SOCKET_IOCBASE, 6, int)
 #define EVL_SOCKIOC_SETSENDSZ	_IOW(EVL_SOCKET_IOCBASE, 7, int)
 
-#endif /* !_EVL_UAPI_NET_SOCKET_H */
+#endif /* !_EVL_UAPI_NET_SOCKET_ABI_H */
diff --git a/include/uapi/evl/observable.h b/include/uapi/evl/observable-abi.h
similarity index 86%
rename from include/uapi/evl/observable.h
rename to include/uapi/evl/observable-abi.h
index 5e610bde4b5660..3da0a47aef3615 100644
--- a/include/uapi/evl/observable.h
+++ b/include/uapi/evl/observable-abi.h
@@ -4,10 +4,10 @@
  * Copyright (C) 2020 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_OBSERVABLE_H
-#define _EVL_UAPI_OBSERVABLE_H
+#ifndef _EVL_UAPI_OBSERVABLE_ABI_H
+#define _EVL_UAPI_OBSERVABLE_ABI_H
 
-#include <uapi/evl/types.h>
+#include <evl/types.h>
 
 #define EVL_OBSERVABLE_DEV	"observable"
 
@@ -42,4 +42,4 @@ struct __evl_notification {
 #define EVL_OBSIOC_SUBSCRIBE		_IOW(EVL_OBSERVABLE_IOCBASE, 0, struct evl_subscription)
 #define EVL_OBSIOC_UNSUBSCRIBE		_IO(EVL_OBSERVABLE_IOCBASE, 1)
 
-#endif /* !_EVL_UAPI_OBSERVABLE_H */
+#endif /* !_EVL_UAPI_OBSERVABLE_ABI_H */
diff --git a/include/uapi/evl/poll.h b/include/uapi/evl/poll-abi.h
similarity index 86%
rename from include/uapi/evl/poll.h
rename to include/uapi/evl/poll-abi.h
index d9475b8d310465..ba2816e62a3bf3 100644
--- a/include/uapi/evl/poll.h
+++ b/include/uapi/evl/poll-abi.h
@@ -4,10 +4,10 @@
  * Copyright (C) 2018 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_POLL_H
-#define _EVL_UAPI_POLL_H
+#ifndef _EVL_UAPI_POLL_ABI_H
+#define _EVL_UAPI_POLL_ABI_H
 
-#include <uapi/evl/types.h>
+#include <evl/types.h>
 
 #define EVL_POLL_DEV		"poll"
 
@@ -39,4 +39,4 @@ struct evl_poll_waitreq {
 #define EVL_POLIOC_CTL		_IOW(EVL_POLL_IOCBASE, 0, struct evl_poll_ctlreq)
 #define EVL_POLIOC_WAIT		_IOWR(EVL_POLL_IOCBASE, 1, struct evl_poll_waitreq)
 
-#endif /* !_EVL_UAPI_POLL_H */
+#endif /* !_EVL_UAPI_POLL_ABI_H */
diff --git a/include/uapi/evl/proxy.h b/include/uapi/evl/proxy-abi.h
similarity index 72%
rename from include/uapi/evl/proxy.h
rename to include/uapi/evl/proxy-abi.h
index 4b01a3b72ee289..6425e282ba4de0 100644
--- a/include/uapi/evl/proxy.h
+++ b/include/uapi/evl/proxy-abi.h
@@ -4,8 +4,8 @@
  * Copyright (C) 2019 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_PROXY_H
-#define _EVL_UAPI_PROXY_H
+#ifndef _EVL_UAPI_PROXY_ABI_H
+#define _EVL_UAPI_PROXY_ABI_H
 
 #include <linux/types.h>
 
@@ -17,4 +17,4 @@ struct evl_proxy_attrs {
 	__u32 granularity;
 };
 
-#endif /* !_EVL_UAPI_PROXY_H */
+#endif /* !_EVL_UAPI_PROXY_ABI_H */
diff --git a/include/uapi/evl/sched.h b/include/uapi/evl/sched-abi.h
similarity index 95%
rename from include/uapi/evl/sched.h
rename to include/uapi/evl/sched-abi.h
index f66081a56ab7e7..8c453c86c78891 100644
--- a/include/uapi/evl/sched.h
+++ b/include/uapi/evl/sched-abi.h
@@ -5,10 +5,10 @@
  * Copyright (C) 2005, 2018 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_SCHED_H
-#define _EVL_UAPI_SCHED_H
+#ifndef _EVL_UAPI_SCHED_ABI_H
+#define _EVL_UAPI_SCHED_ABI_H
 
-#include <uapi/evl/types.h>
+#include <evl/types.h>
 
 #define EVL_CPU_OOB      (1 << 0)
 #define EVL_CPU_ISOL     (1 << 1)
@@ -130,4 +130,4 @@ struct evl_sched_ctlreq {
 	__u64 info_ptr;	 /* (union evl_sched_ctlinfo __user *info) */
 };
 
-#endif /* !_EVL_UAPI_SCHED_H */
+#endif /* !_EVL_UAPI_SCHED_ABI_H */
diff --git a/include/uapi/evl/syscall.h b/include/uapi/evl/syscall-abi.h
similarity index 73%
rename from include/uapi/evl/syscall.h
rename to include/uapi/evl/syscall-abi.h
index 1378aeb6d7dcd0..ecc2412f31b773 100644
--- a/include/uapi/evl/syscall.h
+++ b/include/uapi/evl/syscall-abi.h
@@ -4,8 +4,8 @@
  * Copyright (C) 2018 Philippe Gerum <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_SYSCALL_H
-#define _EVL_UAPI_SYSCALL_H
+#ifndef _EVL_UAPI_SYSCALL_ABI_H
+#define _EVL_UAPI_SYSCALL_ABI_H
 
 #define sys_evl_read	0	/* oob_read() */
 #define sys_evl_write	1	/* oob_write() */
@@ -13,4 +13,4 @@
 
 #define NR_EVL_SYSCALLS 3
 
-#endif /* !_EVL_UAPI_SYSCALL_H */
+#endif /* !_EVL_UAPI_SYSCALL_ABI_H */
diff --git a/include/uapi/evl/thread.h b/include/uapi/evl/thread-abi.h
similarity index 97%
rename from include/uapi/evl/thread.h
rename to include/uapi/evl/thread-abi.h
index c8aed16319465c..8b3c76aa2176a0 100644
--- a/include/uapi/evl/thread.h
+++ b/include/uapi/evl/thread-abi.h
@@ -5,11 +5,10 @@
  * Copyright (C) 2005, 2018 Philippe Gerum <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_THREAD_H
-#define _EVL_UAPI_THREAD_H
+#ifndef _EVL_UAPI_THREAD_ABI_H
+#define _EVL_UAPI_THREAD_ABI_H
 
-#include <linux/types.h>
-#include <uapi/evl/sched.h>
+#include <evl/sched-abi.h>
 
 #define EVL_THREAD_DEV		"thread"
 
@@ -131,4 +130,4 @@ struct evl_thread_state {
 #define EVL_THRIOC_DEMOTE		_IO(EVL_THREAD_IOCBASE, 11)
 #define EVL_THRIOC_YIELD		_IO(EVL_THREAD_IOCBASE, 12)
 
-#endif /* !_EVL_UAPI_THREAD_H */
+#endif /* !_EVL_UAPI_THREAD_ABI_H */
diff --git a/include/uapi/evl/xbuf.h b/include/uapi/evl/xbuf-abi.h
similarity index 72%
rename from include/uapi/evl/xbuf.h
rename to include/uapi/evl/xbuf-abi.h
index d24c896160d35a..816496cf2b9329 100644
--- a/include/uapi/evl/xbuf.h
+++ b/include/uapi/evl/xbuf-abi.h
@@ -4,8 +4,8 @@
  * Copyright (C) 2018 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#ifndef _EVL_UAPI_XBUF_H
-#define _EVL_UAPI_XBUF_H
+#ifndef _EVL_UAPI_XBUF_ABI_H
+#define _EVL_UAPI_XBUF_ABI_H
 
 #include <linux/types.h>
 
@@ -16,4 +16,4 @@ struct evl_xbuf_attrs {
 	__u32 o_bufsz;
 };
 
-#endif /* !_EVL_UAPI_XBUF_H */
+#endif /* !_EVL_UAPI_XBUF_ABI_H */
diff --git a/kernel/evl/clock.c b/kernel/evl/clock.c
index e72db15cc6ca84..3e8dd473f66b5a 100644
--- a/kernel/evl/clock.c
+++ b/kernel/evl/clock.c
@@ -34,8 +34,6 @@
 #include <evl/irq.h>
 #include <evl/uaccess.h>
 #include <asm/evl/calibration.h>
-#include <uapi/evl/factory.h>
-#include <uapi/evl/clock.h>
 #include <trace/events/evl.h>
 
 static const struct file_operations clock_fops;
diff --git a/kernel/evl/control.c b/kernel/evl/control.c
index f58dc8139edb2c..6c27dabe132cae 100644
--- a/kernel/evl/control.c
+++ b/kernel/evl/control.c
@@ -9,17 +9,13 @@
 #include <linux/sched/isolation.h>
 #include <linux/bitmap.h>
 #include <evl/memory.h>
-#include <evl/thread.h>
 #include <evl/factory.h>
-#include <evl/flag.h>
 #include <evl/tick.h>
-#include <evl/sched.h>
 #include <evl/control.h>
 #include <evl/net/input.h>
 #include <evl/net/skb.h>
 #include <evl/uaccess.h>
 #include <asm/evl/fptest.h>
-#include <uapi/evl/control.h>
 
 static BLOCKING_NOTIFIER_HEAD(state_notifier_list);
 
diff --git a/kernel/evl/factory.c b/kernel/evl/factory.c
index 17ea7567d1f9ca..ffffa3a6a5a8dc 100644
--- a/kernel/evl/factory.c
+++ b/kernel/evl/factory.c
@@ -27,10 +27,9 @@
 #include <evl/assert.h>
 #include <evl/file.h>
 #include <evl/control.h>
-#include <evl/syscall.h>
 #include <evl/factory.h>
 #include <evl/uaccess.h>
-#include <uapi/evl/factory.h>
+#include <uapi/evl/syscall-abi.h>
 
 static struct class *evl_class;
 
diff --git a/kernel/evl/memory.c b/kernel/evl/memory.c
index 7d60bc7ae068ee..232b8900cb9aa6 100644
--- a/kernel/evl/memory.c
+++ b/kernel/evl/memory.c
@@ -18,11 +18,9 @@
 #include <linux/vmalloc.h>
 #include <linux/uaccess.h>
 #include <evl/memory.h>
-#include <evl/factory.h>
+#include <evl/monitor.h>
 #include <evl/assert.h>
 #include <evl/init.h>
-#include <uapi/evl/thread.h>
-#include <uapi/evl/monitor.h>
 
 static unsigned long sysheap_size_arg;
 module_param_named(sysheap_size, sysheap_size_arg, ulong, 0444);
diff --git a/kernel/evl/monitor.c b/kernel/evl/monitor.c
index aac19df39f7a1f..8c78f53831ea77 100644
--- a/kernel/evl/monitor.c
+++ b/kernel/evl/monitor.c
@@ -8,20 +8,20 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <evl/thread.h>
-#include <evl/wait.h>
 #include <evl/mutex.h>
-#include <evl/clock.h>
-#include <evl/monitor.h>
 #include <evl/thread.h>
 #include <evl/memory.h>
-#include <evl/sched.h>
 #include <evl/factory.h>
-#include <evl/syscall.h>
+#include <evl/monitor.h>
 #include <evl/poll.h>
 #include <evl/uaccess.h>
-#include <uapi/evl/monitor.h>
 #include <trace/events/evl.h>
 
+static __always_inline  atomic_t *__ATOMIC32(__u32 *ptr)
+{
+	return (atomic_t *)ptr;
+}
+
 struct evl_monitor {
 	struct evl_element element;
 	struct evl_monitor_state *state;
@@ -290,13 +290,13 @@ static int trywait_count(struct evl_monitor *event)
 	int ret = 0, val;
 
 	/* atomic_dec_unless_zero_or_negative */
-	val = atomic_read(&state->u.event.value);
+	val = atomic_read(__ATOMIC32(&state->u.event.value));
 	do {
 		if (unlikely(val <= 0)) {
 			ret = -EAGAIN;
 			break;
 		}
-	} while (!atomic_try_cmpxchg(&state->u.event.value, &val, val - 1));
+	} while (!atomic_try_cmpxchg(__ATOMIC32(&state->u.event.value), &val, val - 1));
 
 	return ret;
 }
@@ -320,14 +320,14 @@ static int wait_count(struct file *filp,
 		 * likely going to wait anyway.
 		 */
 		raw_spin_lock_irqsave(&event->wait_queue.wchan.lock, flags);
-		if (atomic_dec_return(&state->u.event.value) < 0) {
+		if (atomic_dec_return(__ATOMIC32(&state->u.event.value)) < 0) {
 			evl_add_wait_queue(&event->wait_queue,
 					timeout, tmode);
 			raw_spin_unlock_irqrestore(&event->wait_queue.wchan.lock,
 						flags);
 			ret = evl_wait_schedule(&event->wait_queue);
 			if (ret) { /* Rollback decrement if failed. */
-				atomic_inc(&state->u.event.value);
+				atomic_inc(__ATOMIC32(&state->u.event.value));
 			} else {
 				/*
 				 * If waking up on a broadcast, we did
@@ -376,11 +376,11 @@ static int post_count(struct evl_monitor *event, s32 sigval,
 			 * added back to the count.
 			 */
 			if (val > 0)
-				atomic_add(val, &state->u.event.value);
+				atomic_add(val, __ATOMIC32(&state->u.event.value));
 			/* Userland might have slipped in, re-check. */
-			pollable = atomic_read(&state->u.event.value) > 0;
+			pollable = atomic_read(__ATOMIC32(&state->u.event.value)) > 0;
 		} else {
-			if (atomic_inc_return(&state->u.event.value) <= 0) {
+			if (atomic_inc_return(__ATOMIC32(&state->u.event.value)) <= 0) {
 				evl_wake_up_head(&event->wait_queue);
 				pollable = false;
 			}
@@ -407,11 +407,11 @@ static bool __trywait_mask(struct evl_monitor *event,
 	struct evl_monitor_state *state = event->state;
 	int testval;
 
-	*r_value = atomic_read(&state->u.event.value) & match_value;
+	*r_value = atomic_read(__ATOMIC32(&state->u.event.value)) & match_value;
 	testval = exact_match ? match_value : *r_value;
 	if (*r_value && *r_value == testval) {
-		atomic_andnot(*r_value, &state->u.event.value);
-		testval = atomic_read(&state->u.event.value);
+		atomic_andnot(*r_value, __ATOMIC32(&state->u.event.value));
+		testval = atomic_read(__ATOMIC32(&state->u.event.value));
 		raw_spin_unlock_irqrestore(&event->wait_queue.wchan.lock, flags);
 		if (!testval) {
 			evl_signal_poll_events(&event->poll_head, POLLOUT|POLLWRNORM);
@@ -512,11 +512,11 @@ static int post_mask(struct evl_monitor *event, int bits, bool bcast)
 	 * word when an ABI jump is required from applications for
 	 * some compelling reason.
 	 */
-	atomic_or(bits, &state->u.event.value);
+	atomic_or(bits, __ATOMIC32(&state->u.event.value));
 
 	evl_for_each_waiter_safe(waiter, tmp, &event->wait_queue) {
 		w = waiter->wait_data;
-		waitval = w->value & atomic_read(&state->u.event.value);
+		waitval = w->value & atomic_read(__ATOMIC32(&state->u.event.value));
 		testval = w->exact_match ? w->value : waitval;
 		if (waitval && waitval == testval) {
 			w->value = waitval;
@@ -528,9 +528,9 @@ static int post_mask(struct evl_monitor *event, int bits, bool bcast)
 	}
 
 	if (consumed)
-		atomic_andnot(consumed, &state->u.event.value);
+		atomic_andnot(consumed, __ATOMIC32(&state->u.event.value));
 
-	val = atomic_read(&state->u.event.value);
+	val = atomic_read(__ATOMIC32(&state->u.event.value));
 
 	raw_spin_unlock_irqrestore(&event->wait_queue.wchan.lock, flags);
 
@@ -874,7 +874,7 @@ static void monitor_unwatch(struct evl_poll_head *head)
 	struct evl_monitor *mon;
 
 	mon = container_of(head, struct evl_monitor, poll_head);
-	atomic_dec(&mon->state->u.event.pollrefs);
+	atomic_dec(__ATOMIC32(&mon->state->u.event.pollrefs));
 }
 
 static __poll_t monitor_oob_poll(struct file *filp,
@@ -895,8 +895,8 @@ static __poll_t monitor_oob_poll(struct file *filp,
 		switch (mon->protocol) {
 		case EVL_EVENT_COUNT:
 			evl_poll_watch(&mon->poll_head, wait, monitor_unwatch);
-			atomic_inc(&state->u.event.pollrefs);
-			if (atomic_read(&state->u.event.value) > 0)
+			atomic_inc(__ATOMIC32(&state->u.event.pollrefs));
+			if (atomic_read(__ATOMIC32(&state->u.event.value)) > 0)
 				ret = POLLIN|POLLRDNORM;
 			break;
 		case EVL_EVENT_MASK:
@@ -906,8 +906,8 @@ static __poll_t monitor_oob_poll(struct file *filp,
 			 * date as long as we support legacy ABIs
 			 * (pre-32).
 			 */
-			atomic_inc(&state->u.event.pollrefs);
-			val = atomic_read(&state->u.event.value);
+			atomic_inc(__ATOMIC32(&state->u.event.pollrefs));
+			val = atomic_read(__ATOMIC32(&state->u.event.value));
 			/*
 			 * Return POLLIN when some bits are present,
 			 * ready for consumption, or POLLOUT when the
@@ -1046,12 +1046,12 @@ monitor_factory_build(struct evl_factory *fac, const char __user *u_name,
 		case EVL_GATE_PP:
 			state->u.gate.ceiling = attrs.initval;
 			evl_init_mutex_pp(&mon->mutex, clock,
-					&state->u.gate.owner,
+					__ATOMIC32(&state->u.gate.owner),
 					&state->u.gate.ceiling);
 			break;
 		case EVL_GATE_PI:
 			evl_init_mutex_pi(&mon->mutex, clock,
-					&state->u.gate.owner);
+					__ATOMIC32(&state->u.gate.owner));
 			break;
 		}
 		raw_spin_lock_init(&mon->lock);
@@ -1060,7 +1060,7 @@ monitor_factory_build(struct evl_factory *fac, const char __user *u_name,
 	case EVL_MONITOR_EVENT:
 		evl_init_wait(&mon->wait_queue, clock, EVL_WAIT_PRIO);
 		state->u.event.gate_offset = EVL_MONITOR_NOGATE;
-		atomic_set(&state->u.event.value, attrs.initval);
+		atomic_set(__ATOMIC32(&state->u.event.value), attrs.initval);
 		evl_init_poll_head(&mon->poll_head);
 	}
 
@@ -1134,11 +1134,11 @@ static ssize_t state_show(struct device *dev,
 		switch (mon->protocol) {
 		case EVL_EVENT_MASK:
 			ret = snprintf(buf, PAGE_SIZE, "%#x\n",
-				atomic_read(&state->u.event.value));
+			       atomic_read(__ATOMIC32(&state->u.event.value)));
 			break;
 		case EVL_EVENT_COUNT:
 			ret = snprintf(buf, PAGE_SIZE, "%d\n",
-				atomic_read(&state->u.event.value));
+			       atomic_read(__ATOMIC32(&state->u.event.value)));
 			break;
 		case EVL_EVENT_GATED:
 			ret = snprintf(buf, PAGE_SIZE, "%#x\n",
@@ -1146,7 +1146,7 @@ static ssize_t state_show(struct device *dev,
 			break;
 		}
 	} else {
-		fun = atomic_read(&state->u.gate.owner);
+		fun = atomic_read(__ATOMIC32(&state->u.gate.owner));
 		if (fun != EVL_NO_HANDLE) {
 			owner = evl_get_factory_element_by_fundle(&evl_thread_factory,
 						evl_get_index(fun),
diff --git a/kernel/evl/mutex.c b/kernel/evl/mutex.c
index bb57f3d8d93d08..aa32059054a6aa 100644
--- a/kernel/evl/mutex.c
+++ b/kernel/evl/mutex.c
@@ -2,17 +2,14 @@
  * SPDX-License-Identifier: GPL-2.0
  *
  * Derived from Xenomai Cobalt, https://xenomai.org/
- * Copyright (C) 2001, 2019 Philippe Gerum  <rpm@xenomai.org>
+ * Copyright (C) 2001, 2019, 2022 Philippe Gerum  <rpm@xenomai.org>
+ * Copyright (C) 2008, 2009 Jan Kiszka <jan.kiszka@siemens.com>.
  */
 
 #include <linux/kernel.h>
 #include <evl/timer.h>
-#include <evl/clock.h>
-#include <evl/sched.h>
 #include <evl/thread.h>
 #include <evl/mutex.h>
-#include <evl/monitor.h>
-#include <evl/wait.h>
 #include <evl/lock.h>
 #include <uapi/evl/signal.h>
 #include <trace/events/evl.h>
diff --git a/kernel/evl/net/qdisc/fifo.c b/kernel/evl/net/qdisc/fifo.c
index a1d8e97da88950..0d4d2448d39aa6 100644
--- a/kernel/evl/net/qdisc/fifo.c
+++ b/kernel/evl/net/qdisc/fifo.c
@@ -9,7 +9,6 @@
 #include <linux/skbuff.h>
 #include <evl/list.h>
 #include <evl/net/qdisc.h>
-#include <uapi/evl/net/sched.h>
 
 struct qdisc_fifo_priv {
 	struct evl_net_skb_queue q;
diff --git a/kernel/evl/observable.c b/kernel/evl/observable.c
index d488335514043b..b38edd82984ed8 100644
--- a/kernel/evl/observable.c
+++ b/kernel/evl/observable.c
@@ -9,7 +9,6 @@
 #include <linux/rbtree.h>
 #include <linux/poll.h>
 #include <linux/rbtree.h>
-#include <evl/list.h>
 #include <evl/sched.h>
 #include <evl/thread.h>
 #include <evl/clock.h>
diff --git a/kernel/evl/proxy.c b/kernel/evl/proxy.c
index e18fcedf284ec7..35f07a2adb6d3b 100644
--- a/kernel/evl/proxy.c
+++ b/kernel/evl/proxy.c
@@ -19,7 +19,7 @@
 #include <evl/work.h>
 #include <evl/flag.h>
 #include <evl/poll.h>
-#include <uapi/evl/proxy.h>
+#include <uapi/evl/proxy-abi.h>
 
 #define EVL_PROXY_CLONE_FLAGS	\
 	(EVL_CLONE_PUBLIC|EVL_CLONE_OUTPUT|EVL_CLONE_INPUT)
diff --git a/kernel/evl/sched/core.c b/kernel/evl/sched/core.c
index 3bfbe37b1eb7bd..be5c9923e78106 100644
--- a/kernel/evl/sched/core.c
+++ b/kernel/evl/sched/core.c
@@ -19,7 +19,6 @@
 #include <evl/thread.h>
 #include <evl/timer.h>
 #include <evl/memory.h>
-#include <evl/clock.h>
 #include <evl/tick.h>
 #include <evl/monitor.h>
 #include <evl/mutex.h>
diff --git a/kernel/evl/sched/quota.c b/kernel/evl/sched/quota.c
index 158bb2e2423e5b..70b64cb4e05a5e 100644
--- a/kernel/evl/sched/quota.c
+++ b/kernel/evl/sched/quota.c
@@ -9,7 +9,7 @@
 #include <asm/div64.h>
 #include <evl/sched.h>
 #include <evl/memory.h>
-#include <uapi/evl/sched.h>
+#include <uapi/evl/sched-abi.h>
 
 /*
  * With this policy, each per-CPU runqueue maintains a list of active
diff --git a/kernel/evl/sched/tp.c b/kernel/evl/sched/tp.c
index d55b214f81e609..a4054266ef2cd9 100644
--- a/kernel/evl/sched/tp.c
+++ b/kernel/evl/sched/tp.c
@@ -8,7 +8,7 @@
 #include <linux/err.h>
 #include <evl/sched.h>
 #include <evl/memory.h>
-#include <uapi/evl/sched.h>
+#include <uapi/evl/sched-abi.h>
 
 static void tp_schedule_next(struct evl_sched_tp *tp)
 {
diff --git a/kernel/evl/sched/weak.c b/kernel/evl/sched/weak.c
index 5dfd470009a6f2..b3d25186cbc4a8 100644
--- a/kernel/evl/sched/weak.c
+++ b/kernel/evl/sched/weak.c
@@ -6,7 +6,7 @@
  */
 
 #include <evl/sched.h>
-#include <uapi/evl/sched.h>
+#include <uapi/evl/sched-abi.h>
 
 static void weak_init(struct evl_rq *rq)
 {
diff --git a/kernel/evl/sem.c b/kernel/evl/sem.c
index f3e1e467681513..7609e35d4a4a57 100644
--- a/kernel/evl/sem.c
+++ b/kernel/evl/sem.c
@@ -4,9 +4,6 @@
  * Copyright (C) 2019 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#include <evl/timer.h>
-#include <evl/wait.h>
-#include <evl/clock.h>
 #include <evl/sched.h>
 #include <evl/sem.h>
 
diff --git a/kernel/evl/syscall.c b/kernel/evl/syscall.c
index 216c8108b021a6..c2a3f13ebe372d 100644
--- a/kernel/evl/syscall.c
+++ b/kernel/evl/syscall.c
@@ -17,17 +17,12 @@
 #include <linux/atomic.h>
 #include <linux/sched/task_stack.h>
 #include <linux/sched/signal.h>
-#include <evl/control.h>
 #include <evl/thread.h>
-#include <evl/timer.h>
-#include <evl/monitor.h>
-#include <evl/clock.h>
 #include <evl/sched.h>
-#include <evl/file.h>
-#include <trace/events/evl.h>
 #include <asm/syscall.h>
-#include <uapi/evl/syscall.h>
+#include <uapi/evl/syscall-abi.h>
 #include <asm/evl/syscall.h>
+#include <trace/events/evl.h>
 
 #define EVL_SYSCALL(__name, __args)		\
 	long EVL_ ## __name __args
diff --git a/kernel/evl/thread.c b/kernel/evl/thread.c
index 5cd1539cd3a31a..1c5bfe12d231cb 100644
--- a/kernel/evl/thread.c
+++ b/kernel/evl/thread.c
@@ -23,16 +23,9 @@
 #include <linux/ptrace.h>
 #include <linux/math64.h>
 #include <linux/cn_proc.h>
-#include <uapi/linux/sched/types.h>
-#include <evl/sched.h>
-#include <evl/timer.h>
-#include <evl/wait.h>
-#include <evl/clock.h>
-#include <evl/stat.h>
 #include <evl/assert.h>
 #include <evl/thread.h>
 #include <evl/memory.h>
-#include <evl/file.h>
 #include <evl/monitor.h>
 #include <evl/mutex.h>
 #include <evl/poll.h>
@@ -41,6 +34,7 @@
 #include <evl/observable.h>
 #include <evl/uaccess.h>
 #include <evl/lock.h>
+#include <uapi/linux/sched/types.h>
 #include <trace/events/evl.h>
 
 #define EVL_THREAD_CLONE_FLAGS	\
diff --git a/kernel/evl/tick.c b/kernel/evl/tick.c
index 8a3a02c665fd22..3d9c433631ceab 100644
--- a/kernel/evl/tick.c
+++ b/kernel/evl/tick.c
@@ -8,17 +8,11 @@
 #include <linux/cpumask.h>
 #include <linux/clockchips.h>
 #include <linux/tick.h>
-#include <linux/irqdomain.h>
 #include <linux/ktime.h>
 #include <linux/kernel.h>
 #include <linux/timekeeping.h>
 #include <linux/irq_pipeline.h>
-#include <linux/slab.h>
-#include <evl/sched.h>
-#include <evl/timer.h>
-#include <evl/clock.h>
 #include <evl/tick.h>
-#include <evl/control.h>
 #include <trace/events/evl.h>
 
 static DEFINE_PER_CPU(struct clock_proxy_device *, proxy_device);
diff --git a/kernel/evl/timer.c b/kernel/evl/timer.c
index a53a53eb3e6f95..ec372f9cda21cc 100644
--- a/kernel/evl/timer.c
+++ b/kernel/evl/timer.c
@@ -6,13 +6,8 @@
  * Copyright (C) 2001, 2018 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#include <linux/sched.h>
-#include <linux/cred.h>
-#include <linux/err.h>
-#include <evl/sched.h>
 #include <evl/thread.h>
 #include <evl/timer.h>
-#include <evl/clock.h>
 #include <evl/tick.h>
 #include <asm/div64.h>
 #include <trace/events/evl.h>
diff --git a/kernel/evl/wait.c b/kernel/evl/wait.c
index 26d48cee3b5519..69f24e73588789 100644
--- a/kernel/evl/wait.c
+++ b/kernel/evl/wait.c
@@ -6,10 +6,8 @@
  */
 
 #include <evl/lock.h>
-#include <evl/sched.h>
 #include <evl/wait.h>
 #include <evl/thread.h>
-#include <evl/clock.h>
 #include <uapi/evl/signal.h>
 #include <trace/events/evl.h>
 
diff --git a/kernel/evl/work.c b/kernel/evl/work.c
index 1c3774482a9b85..4a7f4a0acc0236 100644
--- a/kernel/evl/work.c
+++ b/kernel/evl/work.c
@@ -4,7 +4,6 @@
  * Copyright (C) 2020 Philippe Gerum  <rpm@xenomai.org>
  */
 
-#include <evl/factory.h>
 #include <evl/work.h>
 
 static void do_wq_work(struct work_struct *wq_work)
diff --git a/kernel/evl/xbuf.c b/kernel/evl/xbuf.c
index 05423fe876da73..fca6d2a834013d 100644
--- a/kernel/evl/xbuf.c
+++ b/kernel/evl/xbuf.c
@@ -12,16 +12,13 @@
 #include <linux/wait.h>
 #include <linux/log2.h>
 #include <linux/atomic.h>
-#include <evl/wait.h>
 #include <evl/thread.h>
-#include <evl/clock.h>
 #include <evl/xbuf.h>
-#include <evl/memory.h>
 #include <evl/factory.h>
 #include <evl/sched.h>
 #include <evl/poll.h>
 #include <evl/flag.h>
-#include <uapi/evl/xbuf.h>
+#include <uapi/evl/xbuf-abi.h>
 
 struct xbuf_ring {
 	void *bufmem;