From: Sirshak Das <sirshak.das@arm.com>
Date: Tue, 28 May 2019 13:44:46 +0000 (-0500)
Subject: Switch atomic test and set API from __sync to __atomic builtin
X-Git-Tag: v20.01-rc0~477
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=3bb6540ab531f5474217f5f1f7cb7b8dce1d4e57;p=vpp.git

Switch atomic test and set API from __sync to __atomic builtin

__sync_test_and_set uses full memory barriers for AArch64,
__atomic_exchange(ACQUIRE) would use load acquire.

Change-Id: Ifdf2481db3b9dde6c5842d75671402862adb6d81
Signed-off-by: Sirshak Das <sirshak.das@arm.com>
Reviewed-by: Lijian Zhang <Lijian.Zhang@arm.com>
Reviewed-by: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
---

diff --git a/src/vppinfra/atomics.h b/src/vppinfra/atomics.h
index 5444b6df350..1d480af407b 100644
--- a/src/vppinfra/atomics.h
+++ b/src/vppinfra/atomics.h
@@ -37,7 +37,7 @@
 #define clib_atomic_cmp_and_swap(addr,old,new) __sync_val_compare_and_swap(addr, old, new)
 #define clib_atomic_bool_cmp_and_swap(addr,old,new) __sync_bool_compare_and_swap(addr, old, new)
 
-#define clib_atomic_test_and_set(a) __sync_lock_test_and_set(a, 1)
+#define clib_atomic_test_and_set(a) __atomic_exchange_n(a, 1, __ATOMIC_ACQUIRE)
 #define clib_atomic_release(a) __sync_lock_release(a)
 
 #define clib_atomic_fence_rel() __atomic_thread_fence(__ATOMIC_RELEASE);