diff --git a/example/generator/odp_generator.c b/example/generator/odp_generator.c
index 7d1c237..73b0369 100644
--- a/example/generator/odp_generator.c
+++ b/example/generator/odp_generator.c
@@ -540,10 +540,10 @@ int main(int argc, char *argv[])
 	}
 
 	/* init counters */
-	odp_atomic_init_u64(&counters.seq);
-	odp_atomic_init_u64(&counters.ip);
-	odp_atomic_init_u64(&counters.udp);
-	odp_atomic_init_u64(&counters.icmp);
+	odp_atomic_init_u64(&counters.seq, 0);
+	odp_atomic_init_u64(&counters.ip, 0);
+	odp_atomic_init_u64(&counters.udp, 0);
+	odp_atomic_init_u64(&counters.icmp, 0);
 
 	/* Reserve memory for args from shared mem */
 	shm = odp_shm_reserve("shm_args", sizeof(args_t),
diff --git a/platform/linux-generic/include/api/odp_atomic.h b/platform/linux-generic/include/api/odp_atomic.h
index 5c83b39..de9d91c 100644
--- a/platform/linux-generic/include/api/odp_atomic.h
+++ b/platform/linux-generic/include/api/odp_atomic.h
@@ -18,11 +18,12 @@
 extern "C" {
 #endif
 
-
-#include <odp_std_types.h>
+#include <stdint.h>
+#include <odp_align.h>
 
 /** @addtogroup odp_synchronizers
- *  Atomic operations.
+ *  Atomic types and relaxed operations. These operations cannot be used for
+ *  synchronization.
  *  @{
  */
 
@@ -30,56 +31,67 @@ extern "C" {
 /**
  * Atomic unsigned integer 64 bits
  */
-typedef volatile uint64_t odp_atomic_u64_t;
+typedef struct {
+	uint64_t v; /**< Actual storage for the atomic variable */
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	/* Some architectures do not support lock-free operations on 64-bit
+	 * data types. We use a spin lock to ensure atomicity. */
+	char lock;
+#endif
+} odp_atomic_u64_t
+ODP_ALIGNED(sizeof(uint64_t)); /* Enforce alignement! */
+
 
 /**
  * Atomic unsigned integer 32 bits
  */
-typedef volatile uint32_t odp_atomic_u32_t;
+typedef struct {
+	uint32_t v; /**< Actual storage for the atomic variable */
+} odp_atomic_u32_t
+ODP_ALIGNED(sizeof(uint32_t)); /* Enforce alignement! */
 
 
 /**
  * Initialize atomic uint32
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
- *
- * @note The operation is not synchronized with other threads
+ * @param val    Value to initialize the variable with
  */
-static inline void odp_atomic_init_u32(odp_atomic_u32_t *ptr)
+static inline void odp_atomic_init_u32(odp_atomic_u32_t *ptr, uint32_t val)
 {
-	*ptr = 0;
+	__atomic_store_n(&ptr->v, val, __ATOMIC_RELAXED);
 }
 
 /**
  * Load value of atomic uint32
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
- * @return atomic uint32 value
- *
- * @note The operation is not synchronized with other threads
+ * @return Value of the variable
  */
 static inline uint32_t odp_atomic_load_u32(odp_atomic_u32_t *ptr)
 {
-	return *ptr;
+	return __atomic_load_n(&ptr->v, __ATOMIC_RELAXED);
 }
 
 /**
  * Store value to atomic uint32
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr        An atomic variable
  * @param new_value  Store new_value to a variable
- *
- * @note The operation is not synchronized with other threads
  */
 static inline void odp_atomic_store_u32(odp_atomic_u32_t *ptr,
 					uint32_t new_value)
 {
-	*ptr = new_value;
+	__atomic_store_n(&ptr->v, new_value, __ATOMIC_RELAXED);
 }
 
 /**
  * Fetch and add atomic uint32
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  * @param value  A value to be added to the variable
@@ -89,11 +101,25 @@ static inline void odp_atomic_store_u32(odp_atomic_u32_t *ptr,
 static inline uint32_t odp_atomic_fetch_add_u32(odp_atomic_u32_t *ptr,
 						uint32_t value)
 {
-	return __sync_fetch_and_add(ptr, value);
+	return __atomic_fetch_add(&ptr->v, value, __ATOMIC_RELAXED);
+}
+
+/**
+ * Add atomic uint32
+ * @note Relaxed memory order, cannot be used for synchronization
+ *
+ * @param ptr    An atomic variable
+ * @param value  A value to be added to the variable
+ */
+static inline void odp_atomic_add_u32(odp_atomic_u32_t *ptr,
+				      uint32_t value)
+{
+	(void)__atomic_fetch_add(&ptr->v, value, __ATOMIC_RELAXED);
 }
 
 /**
  * Fetch and subtract uint32
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  * @param value  A value to be sub to the variable
@@ -103,51 +129,59 @@ static inline uint32_t odp_atomic_fetch_add_u32(odp_atomic_u32_t *ptr,
 static inline uint32_t odp_atomic_fetch_sub_u32(odp_atomic_u32_t *ptr,
 						uint32_t value)
 {
-	return __sync_fetch_and_sub(ptr, value);
+	return __atomic_fetch_sub(&ptr->v, value, __ATOMIC_RELAXED);
+}
+
+/**
+ * Subtract uint32
+ * @note Relaxed memory order, cannot be used for synchronization
+ *
+ * @param ptr    An atomic variable
+ * @param value  A value to be subtract from the variable
+ */
+static inline void odp_atomic_sub_u32(odp_atomic_u32_t *ptr,
+				      uint32_t value)
+{
+	(void)__atomic_fetch_sub(&ptr->v, value, __ATOMIC_RELAXED);
 }
 
 /**
  * Fetch and increment atomic uint32 by 1
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
  * @return Value of the variable before the operation
  */
-#if defined __OCTEON__
 
 static inline uint32_t odp_atomic_fetch_inc_u32(odp_atomic_u32_t *ptr)
 {
+#if defined __OCTEON__
 	uint32_t ret;
-
 	__asm__ __volatile__ ("syncws");
 	__asm__ __volatile__ ("lai %0,(%2)" : "=r" (ret), "+m" (ptr) :
 			      "r" (ptr));
-
 	return ret;
-}
-
 #else
-
-static inline uint32_t odp_atomic_fetch_inc_u32(odp_atomic_u32_t *ptr)
-{
-	return odp_atomic_fetch_add_u32(ptr, 1);
-}
-
+	return __atomic_fetch_add(&ptr->v, 1, __ATOMIC_RELAXED);
 #endif
+}
 
 /**
  * Increment atomic uint32 by 1
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
  */
 static inline void odp_atomic_inc_u32(odp_atomic_u32_t *ptr)
 {
-	odp_atomic_fetch_add_u32(ptr, 1);
+	(void)__atomic_fetch_add(&ptr->v, 1, __ATOMIC_RELAXED);
 }
 
 /**
  * Fetch and decrement uint32 by 1
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
@@ -155,62 +189,77 @@ static inline void odp_atomic_inc_u32(odp_atomic_u32_t *ptr)
  */
 static inline uint32_t odp_atomic_fetch_dec_u32(odp_atomic_u32_t *ptr)
 {
-	return odp_atomic_fetch_sub_u32(ptr, 1);
+	return __atomic_fetch_sub(&ptr->v, 1, __ATOMIC_RELAXED);
 }
 
 /**
  * Decrement atomic uint32 by 1
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
  */
 static inline void odp_atomic_dec_u32(odp_atomic_u32_t *ptr)
 {
-	odp_atomic_fetch_sub_u32(ptr, 1);
+	(void)__atomic_fetch_sub(&ptr->v, 1, __ATOMIC_RELAXED);
 }
 
 /**
- * Atomic compare and set for 32bit
+ * Initialize atomic uint64
+ * @note Relaxed memory order, cannot be used for synchronization
  *
- * @param dst destination location into which the value will be written.
- * @param exp expected value.
- * @param src new value.
- * @return Non-zero on success; 0 on failure.
+ * @param ptr    An atomic variable
+ * @param val    Value to initialize the variable with
  */
-static inline int
-odp_atomic_cmpset_u32(odp_atomic_u32_t *dst, uint32_t exp, uint32_t src)
+static inline void odp_atomic_init_u64(odp_atomic_u64_t *ptr, uint64_t val)
 {
-	return __sync_bool_compare_and_swap(dst, exp, src);
+	ptr->v = val;
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	__atomic_clear(&ptr->lock, __ATOMIC_RELAXED);
+#endif
 }
 
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
 /**
- * Initialize atomic uint64
- *
- * @param ptr    An atomic variable
- *
- * @note The operation is not synchronized with other threads
+ * @internal
+ * Helper macro for lock-based atomic operations on 64-bit integers
+ * @param ptr Pointer to the 64-bit atomic variable
+ * @param expr Expression used update the variable.
+ * @return The old value of the variable.
  */
-static inline void odp_atomic_init_u64(odp_atomic_u64_t *ptr)
-{
-	*ptr = 0;
-}
+#define ATOMIC_OP(ptr, expr) \
+({ \
+	uint64_t old_val; \
+	/* Loop while lock is already taken, stop when lock becomes clear */ \
+	while (__atomic_test_and_set(&(ptr)->lock, __ATOMIC_ACQUIRE)) \
+		(void)0; \
+	old_val = (ptr)->v; \
+	(expr); /* Perform whatever update is desired */ \
+	__atomic_clear(&(ptr)->lock, __ATOMIC_RELEASE); \
+	old_val; /* Return old value */ \
+})
+#endif
 
 /**
  * Load value of atomic uint64
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
  * @return atomic uint64 value
- *
- * @note The operation is not synchronized with other threads
  */
 static inline uint64_t odp_atomic_load_u64(odp_atomic_u64_t *ptr)
 {
-	return *ptr;
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	return ATOMIC_OP(ptr, (void)0);
+#else
+	return __atomic_load_n(&ptr->v, __ATOMIC_RELAXED);
+#endif
 }
 
 /**
  * Store value to atomic uint64
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr        An atomic variable
  * @param new_value  Store new_value to a variable
@@ -220,23 +269,16 @@ static inline uint64_t odp_atomic_load_u64(odp_atomic_u64_t *ptr)
 static inline void odp_atomic_store_u64(odp_atomic_u64_t *ptr,
 					uint64_t new_value)
 {
-	*ptr = new_value;
-}
-
-/**
- * Add atomic uint64
- *
- * @param ptr    An atomic variable
- * @param value  A value to be added to the variable
- *
- */
-static inline void odp_atomic_add_u64(odp_atomic_u64_t *ptr, uint64_t value)
-{
-	__sync_fetch_and_add(ptr, value);
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	(void)ATOMIC_OP(ptr, ptr->v = new_value);
+#else
+	__atomic_store_n(&ptr->v, new_value, __ATOMIC_RELAXED);
+#endif
 }
 
 /**
  * Fetch and add atomic uint64
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  * @param value  A value to be added to the variable
@@ -244,56 +286,72 @@ static inline void odp_atomic_add_u64(odp_atomic_u64_t *ptr, uint64_t value)
  * @return Value of the variable before the operation
  */
 
-#if defined __powerpc__ && !defined __powerpc64__
 static inline uint64_t odp_atomic_fetch_add_u64(odp_atomic_u64_t *ptr,
 						uint64_t value)
 {
-	return __sync_fetch_and_add((odp_atomic_u32_t *)ptr,
-				    (uint32_t)value);
-}
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	return ATOMIC_OP(ptr, ptr->v += value);
 #else
-static inline uint64_t odp_atomic_fetch_add_u64(odp_atomic_u64_t *ptr,
-						uint64_t value)
-{
-	return __sync_fetch_and_add(ptr, value);
-}
+	return __atomic_fetch_add(&ptr->v, value, __ATOMIC_RELAXED);
 #endif
+}
+
 /**
- * Subtract atomic uint64
+ * Add atomic uint64
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
- * @param value  A value to be subtracted from the variable
+ * @param value  A value to be added to the variable
  *
  */
-static inline void odp_atomic_sub_u64(odp_atomic_u64_t *ptr, uint64_t value)
+static inline void odp_atomic_add_u64(odp_atomic_u64_t *ptr, uint64_t value)
 {
-	__sync_fetch_and_sub(ptr, value);
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	(void)ATOMIC_OP(ptr, ptr->v += value);
+#else
+	(void)__atomic_fetch_add(&ptr->v, value, __ATOMIC_RELAXED);
+#endif
 }
 
 /**
  * Fetch and subtract atomic uint64
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  * @param value  A value to be subtracted from the variable
  *
  * @return Value of the variable before the operation
  */
-#if defined __powerpc__ && !defined __powerpc64__
 static inline uint64_t odp_atomic_fetch_sub_u64(odp_atomic_u64_t *ptr,
 						uint64_t value)
 {
-	return __sync_fetch_and_sub((odp_atomic_u32_t *)ptr,
-				    (uint32_t)value);
-}
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	return ATOMIC_OP(ptr, ptr->v -= value);
 #else
-static inline uint64_t odp_atomic_fetch_sub_u64(odp_atomic_u64_t *ptr,
-						uint64_t value)
-{
-	return __sync_fetch_and_sub(ptr, value);
+	return __atomic_fetch_sub(&ptr->v, value, __ATOMIC_RELAXED);
+#endif
 }
+
+/**
+ * Subtract atomic uint64
+ * @note Relaxed memory order, cannot be used for synchronization
+ *
+ * @param ptr    An atomic variable
+ * @param value  A value to be subtracted from the variable
+ *
+ */
+static inline void odp_atomic_sub_u64(odp_atomic_u64_t *ptr, uint64_t value)
+{
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	(void)ATOMIC_OP(ptr, ptr->v -= value);
+#else
+	(void)__atomic_fetch_sub(&ptr->v, value, __ATOMIC_RELAXED);
 #endif
+}
+
 /**
  * Fetch and increment atomic uint64 by 1
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
@@ -301,22 +359,32 @@ static inline uint64_t odp_atomic_fetch_sub_u64(odp_atomic_u64_t *ptr,
  */
 static inline uint64_t odp_atomic_fetch_inc_u64(odp_atomic_u64_t *ptr)
 {
-	return odp_atomic_fetch_add_u64(ptr, 1);
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	return ATOMIC_OP(ptr, ptr->v++);
+#else
+	return __atomic_fetch_add(&ptr->v, 1, __ATOMIC_RELAXED);
+#endif
 }
 
 /**
  * Increment atomic uint64 by 1
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
  */
 static inline void odp_atomic_inc_u64(odp_atomic_u64_t *ptr)
 {
-	odp_atomic_fetch_add_u64(ptr, 1);
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	(void)ATOMIC_OP(ptr, ptr->v++);
+#else
+	(void)__atomic_fetch_add(&ptr->v, 1, __ATOMIC_RELAXED);
+#endif
 }
 
 /**
  * Fetch and decrement atomic uint64 by 1
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
@@ -324,32 +392,27 @@ static inline void odp_atomic_inc_u64(odp_atomic_u64_t *ptr)
  */
 static inline uint64_t odp_atomic_fetch_dec_u64(odp_atomic_u64_t *ptr)
 {
-	return odp_atomic_fetch_sub_u64(ptr, 1);
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	return ATOMIC_OP(ptr, ptr->v--);
+#else
+	return __atomic_fetch_sub(&ptr->v, 1, __ATOMIC_RELAXED);
+#endif
 }
 
 /**
  * Decrement atomic uint64 by 1
+ * @note Relaxed memory order, cannot be used for synchronization
  *
  * @param ptr    An atomic variable
  *
  */
 static inline void odp_atomic_dec_u64(odp_atomic_u64_t *ptr)
 {
-	odp_atomic_fetch_sub_u64(ptr, 1);
-}
-
-/**
- * Atomic compare and set for 64bit
- *
- * @param dst destination location into which the value will be written.
- * @param exp expected value.
- * @param src new value.
- * @return Non-zero on success; 0 on failure.
- */
-static inline int
-odp_atomic_cmpset_u64(odp_atomic_u64_t *dst, uint64_t exp, uint64_t src)
-{
-	return __sync_bool_compare_and_swap(dst, exp, src);
+#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2
+	(void)ATOMIC_OP(ptr, ptr->v--);
+#else
+	(void)__atomic_fetch_sub(&ptr->v, 1, __ATOMIC_RELAXED);
+#endif
 }
 
 /**
diff --git a/platform/linux-generic/odp_barrier.c b/platform/linux-generic/odp_barrier.c
index de1bf60..3a511b2 100644
--- a/platform/linux-generic/odp_barrier.c
+++ b/platform/linux-generic/odp_barrier.c
@@ -10,9 +10,8 @@
 
 void odp_barrier_init(odp_barrier_t *barrier, int count)
 {
-	barrier->count = count;
-	barrier->bar   = 0;
-	odp_sync_stores();
+	barrier->count = (uint32_t)count;
+	odp_atomic_init_u32(&barrier->bar, 0);
 }
 
 /*
@@ -33,14 +32,16 @@ void odp_barrier_wait(odp_barrier_t *barrier)
 	uint32_t count;
 	int wasless;
 
-	wasless = barrier->bar < barrier->count;
 	__atomic_thread_fence(__ATOMIC_SEQ_CST);
 	count   = odp_atomic_fetch_inc_u32(&barrier->bar);
+	wasless = count < barrier->count;
 
 	if (count == 2*barrier->count-1) {
-		barrier->bar = 0;
+		/* Wrap around *atomically* */
+		odp_atomic_sub_u32(&barrier->bar, 2 * barrier->count);
 	} else {
-		while ((barrier->bar < barrier->count) == wasless)
+		while ((odp_atomic_load_u32(&barrier->bar) < barrier->count)
+				== wasless)
 			odp_spin();
 	}
 
diff --git a/platform/linux-generic/odp_ticketlock.c b/platform/linux-generic/odp_ticketlock.c
index 096bdc0..e60f526 100644
--- a/platform/linux-generic/odp_ticketlock.c
+++ b/platform/linux-generic/odp_ticketlock.c
@@ -12,9 +12,8 @@
 
 void odp_ticketlock_init(odp_ticketlock_t *ticketlock)
 {
-	ticketlock->next_ticket = 0;
+	odp_atomic_init_u32(&ticketlock->next_ticket, 0);
 	ticketlock->cur_ticket  = 0;
-	odp_sync_stores();
 }
 
 
diff --git a/test/api_test/odp_atomic_test.c b/test/api_test/odp_atomic_test.c
index 553c447..dcf2c59 100644
--- a/test/api_test/odp_atomic_test.c
+++ b/test/api_test/odp_atomic_test.c
@@ -152,8 +152,8 @@ void test_atomic_basic(void)
 
 void test_atomic_init(void)
 {
-	odp_atomic_init_u32(&a32u);
-	odp_atomic_init_u64(&a64u);
+	odp_atomic_init_u32(&a32u, 0);
+	odp_atomic_init_u64(&a64u, 0);
 }
 
 void test_atomic_store(void)
