vppinfra: add atomic macros for __sync builtins

This is first part of addition of atomic macros with only macros for
__sync builtins.

- Based on earlier patch by Damjan (https://gerrit.fd.io/r/#/c/10729/)
Additionally
- clib_atomic_release macro added and used in the absence
of any memory barrier.
- clib_atomic_bool_cmp_and_swap added

Change-Id: Ie4e48c1e184a652018d1d0d87c4be80ddd180a3b
Original-patch-by: Damjan Marion <damarion@cisco.com>
Signed-off-by: Sirshak Das <sirshak.das@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Ola Liljedahl <ola.liljedahl@arm.com>
Reviewed-by: Steve Capper <steve.capper@arm.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/vnet/pg/output.c b/src/vnet/pg/output.c
index ab57deefd24..016e5b370e5 100644
--- a/src/vnet/pg/output.c
+++ b/src/vnet/pg/output.c
@@ -54,7 +54,7 @@ pg_output (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
   pg_interface_t *pif = pool_elt_at_index (pg->interfaces, rd->dev_instance);
 
   if (PREDICT_FALSE (pif->lockp != 0))
-    while (__sync_lock_test_and_set (pif->lockp, 1))
+    while (clib_atomic_test_and_set (pif->lockp))
       ;
 
   while (n_left > 0)
@@ -82,7 +82,8 @@ pg_output (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 
   vlib_buffer_free (vm, vlib_frame_args (frame), n_buffers);
   if (PREDICT_FALSE (pif->lockp != 0))
-    *pif->lockp = 0;
+    clib_atomic_release (pif->lockp);
+
   return n_buffers;
 }