From: Olivier Dion <odion@efficios.com>
Date: Fri, 17 Mar 2023 21:37:51 +0000 (+0100)
Subject: urcu/compiler: Use atomic builtins if configured
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=865024e9245c55286122413aaf7366dc06a00f27;p=urcu.git

urcu/compiler: Use atomic builtins if configured

Use __atomic_signal_fence(__ATOMIC_SEQ_CST) for cmm_barrier() if
configured to use atomic builtins.

Change-Id: Ib168b50f1e97a8da861b92d6882c56db230ebb2c
Co-authored-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/include/urcu/compiler.h b/include/urcu/compiler.h
index 5b99407..4821129 100644
--- a/include/urcu/compiler.h
+++ b/include/urcu/compiler.h
@@ -15,10 +15,16 @@
 # include <type_traits>	/* for std::remove_cv */
 #endif
 
+#include <urcu/config.h>
+
 #define caa_likely(x)	__builtin_expect(!!(x), 1)
 #define caa_unlikely(x)	__builtin_expect(!!(x), 0)
 
-#define	cmm_barrier()	__asm__ __volatile__ ("" : : : "memory")
+#ifdef CONFIG_RCU_USE_ATOMIC_BUILTINS
+#  define cmm_barrier() __atomic_signal_fence(__ATOMIC_SEQ_CST)
+#else
+#  define cmm_barrier() __asm__ __volatile__ ("" : : : "memory")
+#endif
 
 /*
  * Instruct the compiler to perform only a single access to a variable