atomic/detail/wait_ops_freebsd_umtx.hpp

0001 /*
0002  * Distributed under the Boost Software License, Version 1.0.
0003  * (See accompanying file LICENSE_1_0.txt or copy at
0004  * http://www.boost.org/LICENSE_1_0.txt)
0005  *
0006  * Copyright (c) 2020 Andrey Semashev
0007  */
0008 /*!
0009  * \file   atomic/detail/wait_ops_freebsd_umtx.hpp
0010  *
0011  * This header contains implementation of the waiting/notifying atomic operations based on FreeBSD _umtx_op syscall.
0012  * https://www.freebsd.org/cgi/man.cgi?query=_umtx_op&apropos=0&sektion=2&manpath=FreeBSD+11-current&format=html
0013  */
0014
0015 #ifndef BOOST_ATOMIC_DETAIL_WAIT_OPS_FREEBSD_UMTX_HPP_INCLUDED_
0016 #define BOOST_ATOMIC_DETAIL_WAIT_OPS_FREEBSD_UMTX_HPP_INCLUDED_
0017
0018 #include <sys/types.h>
0019 #include <sys/umtx.h>
0020 #include <cstddef>
0021 #include <boost/memory_order.hpp>
0022 #include <boost/atomic/detail/config.hpp>
0023 #include <boost/atomic/detail/int_sizes.hpp>
0024 #include <boost/atomic/detail/wait_operations_fwd.hpp>
0025 #include <boost/atomic/detail/header.hpp>
0026
0027 #ifdef BOOST_HAS_PRAGMA_ONCE
0028 #pragma once
0029 #endif
0030
0031 namespace boost {
0032 namespace atomics {
0033 namespace detail {
0034
0035 #if defined(UMTX_OP_WAIT_UINT) || defined(UMTX_OP_WAIT)
0036
0037 template< typename Base >
0038 struct wait_operations_freebsd_umtx_common :
0039     public Base
0040 {
0041     typedef Base base_type;
0042     typedef typename base_type::storage_type storage_type;
0043
0044     static BOOST_CONSTEXPR_OR_CONST bool always_has_native_wait_notify = true;
0045
0046     static BOOST_FORCEINLINE bool has_native_wait_notify(storage_type const volatile&) BOOST_NOEXCEPT
0047     {
0048         return true;
0049     }
0050
0051     static BOOST_FORCEINLINE void notify_one(storage_type volatile& storage) BOOST_NOEXCEPT
0052     {
0053         ::_umtx_op(const_cast< storage_type* >(&storage), UMTX_OP_WAKE, 1u, NULL, NULL);
0054     }
0055
0056     static BOOST_FORCEINLINE void notify_all(storage_type volatile& storage) BOOST_NOEXCEPT
0057     {
0058         ::_umtx_op(const_cast< storage_type* >(&storage), UMTX_OP_WAKE, (~static_cast< unsigned int >(0u)) >> 1, NULL, NULL);
0059     }
0060 };
0061
0062 #endif // defined(UMTX_OP_WAIT_UINT) || defined(UMTX_OP_WAIT)
0063
0064 // UMTX_OP_WAIT_UINT only appeared in FreeBSD 8.0
0065 #if defined(UMTX_OP_WAIT_UINT) && BOOST_ATOMIC_DETAIL_SIZEOF_INT < BOOST_ATOMIC_DETAIL_SIZEOF_LONG
0066
0067 template< typename Base, bool Interprocess >
0068 struct wait_operations< Base, sizeof(unsigned int), true, Interprocess > :
0069     public wait_operations_freebsd_umtx_common< Base >
0070 {
0071     typedef wait_operations_freebsd_umtx_common< Base > base_type;
0072     typedef typename base_type::storage_type storage_type;
0073
0074     static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) BOOST_NOEXCEPT
0075     {
0076         storage_type new_val = base_type::load(storage, order);
0077         while (new_val == old_val)
0078         {
0079             ::_umtx_op(const_cast< storage_type* >(&storage), UMTX_OP_WAIT_UINT, old_val, NULL, NULL);
0080             new_val = base_type::load(storage, order);
0081         }
0082
0083         return new_val;
0084     }
0085 };
0086
0087 #endif // defined(UMTX_OP_WAIT_UINT) && BOOST_ATOMIC_DETAIL_SIZEOF_INT < BOOST_ATOMIC_DETAIL_SIZEOF_LONG
0088
0089 #if defined(UMTX_OP_WAIT)
0090
0091 template< typename Base, bool Interprocess >
0092 struct wait_operations< Base, sizeof(unsigned long), true, Interprocess > :
0093     public wait_operations_freebsd_umtx_common< Base >
0094 {
0095     typedef wait_operations_freebsd_umtx_common< Base > base_type;
0096     typedef typename base_type::storage_type storage_type;
0097
0098     static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) BOOST_NOEXCEPT
0099     {
0100         storage_type new_val = base_type::load(storage, order);
0101         while (new_val == old_val)
0102         {
0103             ::_umtx_op(const_cast< storage_type* >(&storage), UMTX_OP_WAIT, old_val, NULL, NULL);
0104             new_val = base_type::load(storage, order);
0105         }
0106
0107         return new_val;
0108     }
0109 };
0110
0111 #endif // defined(UMTX_OP_WAIT)
0112
0113 } // namespace detail
0114 } // namespace atomics
0115 } // namespace boost
0116
0117 #include <boost/atomic/detail/footer.hpp>
0118
0119 #endif // BOOST_ATOMIC_DETAIL_WAIT_OPS_FREEBSD_UMTX_HPP_INCLUDED_