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include/boost/atomic/detail/fence_ops_linux_arm.hpp

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+/*
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * Copyright (c) 2009, 2011 Helge Bahmann
+ * Copyright (c) 2009 Phil Endecott
+ * Copyright (c) 2013 Tim Blechmann
+ * Linux-specific code by Phil Endecott
+ * Copyright (c) 2014-2025 Andrey Semashev
+ */
+/*!
+ * \file   atomic/detail/fence_ops_linux_arm.hpp
+ *
+ * This header contains implementation of the \c fence_operations struct.
+ */
+
+#ifndef BOOST_ATOMIC_DETAIL_FENCE_OPS_LINUX_ARM_HPP_INCLUDED_
+#define BOOST_ATOMIC_DETAIL_FENCE_OPS_LINUX_ARM_HPP_INCLUDED_
+
+#include <boost/memory_order.hpp>
+#include <boost/atomic/detail/config.hpp>
+#include <boost/atomic/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+namespace atomics {
+namespace detail {
+
+//! Fence operations based on Linux-specific system routines
+struct fence_operations_linux_arm
+{
+    static BOOST_FORCEINLINE void thread_fence(memory_order order) noexcept
+    {
+        if (order != memory_order_relaxed)
+            hardware_full_fence();
+    }
+
+    static BOOST_FORCEINLINE void signal_fence(memory_order order) noexcept
+    {
+        if (order != memory_order_relaxed)
+            __asm__ __volatile__ ("" ::: "memory");
+    }
+
+    static BOOST_FORCEINLINE void hardware_full_fence() noexcept
+    {
+        // See the comment in core_ops_linux_arm.hpp regarding the function pointer below
+        using kernel_dmb_t = void (void);
+        ((kernel_dmb_t*)0xffff0fa0)();
+    }
+};
+
+using fence_operations = fence_operations_linux_arm;
+
+} // namespace detail
+} // namespace atomics
+} // namespace boost
+
+#include <boost/atomic/detail/footer.hpp>
+
+#endif // BOOST_ATOMIC_DETAIL_FENCE_OPS_LINUX_ARM_HPP_INCLUDED_