Index: uspace/lib/c/generic/thread/fibril.c
===================================================================
--- uspace/lib/c/generic/thread/fibril.c	(revision ffa73c60dc2eba8ce632c52a0be8bbf4ecd562d9)
+++ uspace/lib/c/generic/thread/fibril.c	(revision fc10e1b945611fb364f75d69f5864f22ed4a8e84)
@@ -88,5 +88,5 @@
 /* This futex serializes access to global data. */
 static futex_t fibril_futex = FUTEX_INITIALIZER;
-static futex_t ready_semaphore = FUTEX_INITIALIZE(0);
+static futex_t ready_semaphore;
 static long ready_st_count;
 
@@ -117,19 +117,4 @@
 }
 
-static inline long _ready_count(void)
-{
-	/*
-	 * The number of available tokens is always equal to the number
-	 * of fibrils in the ready list + the number of free IPC buffer
-	 * buckets.
-	 */
-
-	if (multithreaded)
-		return atomic_get(&ready_semaphore.val);
-
-	_ready_debug_check();
-	return ready_st_count;
-}
-
 static inline void _ready_up(void)
 {
@@ -152,5 +137,5 @@
 }
 
-static atomic_t threads_in_ipc_wait = { 0 };
+static atomic_int threads_in_ipc_wait;
 
 /** Function that spans the whole life-cycle of a fibril.
@@ -303,5 +288,6 @@
 	fibril_t *f = list_pop(&ready_list, fibril_t, link);
 	if (!f)
-		atomic_inc(&threads_in_ipc_wait);
+		atomic_fetch_add_explicit(&threads_in_ipc_wait, 1,
+		    memory_order_relaxed);
 	if (!locked)
 		futex_unlock(&fibril_futex);
@@ -317,5 +303,6 @@
 	rc = _ipc_wait(&call, expires);
 
-	atomic_dec(&threads_in_ipc_wait);
+	atomic_fetch_sub_explicit(&threads_in_ipc_wait, 1,
+	    memory_order_relaxed);
 
 	if (rc != EOK && rc != ENOENT) {
@@ -386,5 +373,5 @@
 	_ready_up();
 
-	if (atomic_get(&threads_in_ipc_wait)) {
+	if (atomic_load_explicit(&threads_in_ipc_wait, memory_order_relaxed)) {
 		DPRINTF("Poking.\n");
 		/* Wakeup one thread sleeping in SYS_IPC_WAIT. */
@@ -811,5 +798,5 @@
 	if (!multithreaded) {
 		_ready_debug_check();
-		atomic_set(&ready_semaphore.val, ready_st_count);
+		futex_initialize(&ready_semaphore, ready_st_count);
 		multithreaded = true;
 	}
Index: uspace/lib/c/generic/thread/futex.c
===================================================================
--- uspace/lib/c/generic/thread/futex.c	(revision ffa73c60dc2eba8ce632c52a0be8bbf4ecd562d9)
+++ uspace/lib/c/generic/thread/futex.c	(revision fc10e1b945611fb364f75d69f5864f22ed4a8e84)
@@ -34,5 +34,5 @@
 
 #include <assert.h>
-#include <atomic.h>
+#include <stdatomic.h>
 #include <fibril.h>
 #include <io/kio.h>
@@ -52,5 +52,5 @@
 void futex_initialize(futex_t *futex, int val)
 {
-	atomic_set(&futex->val, val);
+	atomic_store_explicit(&futex->val, val, memory_order_relaxed);
 }
 
@@ -59,5 +59,5 @@
 void __futex_assert_is_locked(futex_t *futex, const char *name)
 {
-	void *owner = __atomic_load_n(&futex->owner, __ATOMIC_RELAXED);
+	void *owner = atomic_load_explicit(&futex->owner, memory_order_relaxed);
 	fibril_t *self = (fibril_t *) fibril_get_id();
 	if (owner != self) {
@@ -69,5 +69,5 @@
 void __futex_assert_is_not_locked(futex_t *futex, const char *name)
 {
-	void *owner = __atomic_load_n(&futex->owner, __ATOMIC_RELAXED);
+	void *owner = atomic_load_explicit(&futex->owner, memory_order_relaxed);
 	fibril_t *self = (fibril_t *) fibril_get_id();
 	if (owner == self) {
@@ -91,7 +91,8 @@
 	futex_down(futex);
 
-	void *prev_owner = __atomic_load_n(&futex->owner, __ATOMIC_RELAXED);
+	void *prev_owner = atomic_load_explicit(&futex->owner,
+	    memory_order_relaxed);
 	assert(prev_owner == NULL);
-	__atomic_store_n(&futex->owner, self, __ATOMIC_RELAXED);
+	atomic_store_explicit(&futex->owner, self, memory_order_relaxed);
 }
 
@@ -101,5 +102,5 @@
 	DPRINTF("Unlocking futex %s (%p) by fibril %p.\n", name, futex, self);
 	__futex_assert_is_locked(futex, name);
-	__atomic_store_n(&futex->owner, NULL, __ATOMIC_RELAXED);
+	atomic_store_explicit(&futex->owner, NULL, memory_order_relaxed);
 	futex_up(futex);
 }
@@ -110,8 +111,9 @@
 	bool success = futex_trydown(futex);
 	if (success) {
-		void *owner = __atomic_load_n(&futex->owner, __ATOMIC_RELAXED);
+		void *owner = atomic_load_explicit(&futex->owner,
+		    memory_order_relaxed);
 		assert(owner == NULL);
 
-		__atomic_store_n(&futex->owner, self, __ATOMIC_RELAXED);
+		atomic_store_explicit(&futex->owner, self, memory_order_relaxed);
 
 		DPRINTF("Trylock on futex %s (%p) by fibril %p succeeded.\n", name, futex, self);
@@ -130,5 +132,5 @@
 
 	__futex_assert_is_locked(futex, name);
-	__atomic_store_n(&futex->owner, new_owner, __ATOMIC_RELAXED);
+	atomic_store_explicit(&futex->owner, new_owner, memory_order_relaxed);
 }