/*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* Copyright (c) 2020 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/wait_ops_freebsd_umtx.hpp
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*
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* This header contains implementation of the waiting/notifying atomic operations based on FreeBSD _umtx_op syscall.
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* https://www.freebsd.org/cgi/man.cgi?query=_umtx_op&apropos=0&sektion=2&manpath=FreeBSD+11-current&format=html
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*/
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#ifndef BOOST_ATOMIC_DETAIL_WAIT_OPS_FREEBSD_UMTX_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_WAIT_OPS_FREEBSD_UMTX_HPP_INCLUDED_
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#include <sys/types.h>
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#include <sys/umtx.h>
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#include <cstddef>
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#include <boost/memory_order.hpp>
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#include <boost/atomic/detail/config.hpp>
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#include <boost/atomic/detail/int_sizes.hpp>
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#include <boost/atomic/detail/wait_operations_fwd.hpp>
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#include <boost/atomic/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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namespace atomics {
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namespace detail {
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#if defined(UMTX_OP_WAIT_UINT) || defined(UMTX_OP_WAIT)
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template< typename Base >
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struct wait_operations_freebsd_umtx_common :
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public Base
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{
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typedef Base base_type;
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typedef typename base_type::storage_type storage_type;
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static BOOST_CONSTEXPR_OR_CONST bool always_has_native_wait_notify = true;
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static BOOST_FORCEINLINE bool has_native_wait_notify(storage_type const volatile&) BOOST_NOEXCEPT
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{
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return true;
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}
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static BOOST_FORCEINLINE void notify_one(storage_type volatile& storage) BOOST_NOEXCEPT
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{
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::_umtx_op(const_cast< storage_type* >(&storage), UMTX_OP_WAKE, 1u, NULL, NULL);
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}
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static BOOST_FORCEINLINE void notify_all(storage_type volatile& storage) BOOST_NOEXCEPT
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{
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::_umtx_op(const_cast< storage_type* >(&storage), UMTX_OP_WAKE, (~static_cast< unsigned int >(0u)) >> 1, NULL, NULL);
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}
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};
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#endif // defined(UMTX_OP_WAIT_UINT) || defined(UMTX_OP_WAIT)
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// UMTX_OP_WAIT_UINT only appeared in FreeBSD 8.0
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#if defined(UMTX_OP_WAIT_UINT) && BOOST_ATOMIC_DETAIL_SIZEOF_INT < BOOST_ATOMIC_DETAIL_SIZEOF_LONG
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template< typename Base, bool Interprocess >
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struct wait_operations< Base, sizeof(unsigned int), true, Interprocess > :
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public wait_operations_freebsd_umtx_common< Base >
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{
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typedef wait_operations_freebsd_umtx_common< Base > base_type;
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typedef typename base_type::storage_type storage_type;
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static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) BOOST_NOEXCEPT
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{
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storage_type new_val = base_type::load(storage, order);
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while (new_val == old_val)
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{
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::_umtx_op(const_cast< storage_type* >(&storage), UMTX_OP_WAIT_UINT, old_val, NULL, NULL);
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new_val = base_type::load(storage, order);
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}
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return new_val;
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}
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};
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#endif // defined(UMTX_OP_WAIT_UINT) && BOOST_ATOMIC_DETAIL_SIZEOF_INT < BOOST_ATOMIC_DETAIL_SIZEOF_LONG
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#if defined(UMTX_OP_WAIT)
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template< typename Base, bool Interprocess >
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struct wait_operations< Base, sizeof(unsigned long), true, Interprocess > :
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public wait_operations_freebsd_umtx_common< Base >
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{
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typedef wait_operations_freebsd_umtx_common< Base > base_type;
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typedef typename base_type::storage_type storage_type;
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static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) BOOST_NOEXCEPT
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{
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storage_type new_val = base_type::load(storage, order);
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while (new_val == old_val)
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{
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::_umtx_op(const_cast< storage_type* >(&storage), UMTX_OP_WAIT, old_val, NULL, NULL);
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new_val = base_type::load(storage, order);
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}
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return new_val;
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}
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};
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#endif // defined(UMTX_OP_WAIT)
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} // namespace detail
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} // namespace atomics
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} // namespace boost
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#include <boost/atomic/detail/footer.hpp>
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#endif // BOOST_ATOMIC_DETAIL_WAIT_OPS_FREEBSD_UMTX_HPP_INCLUDED_
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