1 /*
2  * Distributed under the Boost Software License, Version 1.0.
3  * (See accompanying file LICENSE_1_0.txt or copy at
4  * http://www.boost.org/LICENSE_1_0.txt)
5  *
6  * Copyright (c) 2021 Andrey Semashev
7  */
8 /*!
9  * \file   atomic/detail/wait_ops_darwin_ulock.hpp
10  *
11  * This header contains implementation of the waiting/notifying atomic operations based on Darwin systems using ulock syscalls.
12  *
13  * https://github.com/apple/darwin-xnu/blob/master/bsd/sys/ulock.h
14  * https://github.com/apple/darwin-xnu/blob/master/bsd/kern/sys_ulock.c
15  */
16 
17 #ifndef BOOST_ATOMIC_DETAIL_WAIT_OPS_DARWIN_ULOCK_HPP_INCLUDED_
18 #define BOOST_ATOMIC_DETAIL_WAIT_OPS_DARWIN_ULOCK_HPP_INCLUDED_
19 
20 #include <stdint.h>
21 #include <cerrno>
22 #include <boost/memory_order.hpp>
23 #include <boost/atomic/detail/config.hpp>
24 #include <boost/atomic/detail/wait_capabilities.hpp>
25 #include <boost/atomic/detail/wait_operations_fwd.hpp>
26 #include <boost/atomic/detail/header.hpp>
27 
28 #ifdef BOOST_HAS_PRAGMA_ONCE
29 #pragma once
30 #endif
31 
32 namespace boost {
33 namespace atomics {
34 namespace detail {
35 
36 extern "C" {
37 // Timeout is in microseconds with zero meaning no timeout
38 int __ulock_wait(uint32_t operation, void* addr, uint64_t value, uint32_t timeout);
39 #if defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_WAIT2)
40 // Timeout is in nanoseconds with zero meaning no timeout
41 int __ulock_wait2(uint32_t operation, void* addr, uint64_t value, uint64_t timeout, uint64_t value2);
42 #endif // defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_WAIT2)
43 int __ulock_wake(uint32_t operation, void* addr, uint64_t wake_value);
44 } // extern "C"
45 
46 enum ulock_op
47 {
48     ulock_op_compare_and_wait = 1,
49 #if defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_SHARED)
50     ulock_op_compare_and_wait_shared = 3,
51 #endif // defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_SHARED)
52 #if defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK64)
53     ulock_op_compare_and_wait64 = 5,
54 #if defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_SHARED)
55     ulock_op_compare_and_wait64_shared = 6,
56 #endif // defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_SHARED)
57 #endif // defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK64)
58 
59     // Flags for __ulock_wake
60     ulock_flag_wake_all = 0x00000100,
61 
62     // Generic flags
63     ulock_flag_no_errno = 0x01000000
64 };
65 
66 template< typename Base, uint32_t Opcode >
67 struct wait_operations_darwin_ulock_common :
68     public Base
69 {
70     typedef Base base_type;
71     typedef typename base_type::storage_type storage_type;
72 
73     static BOOST_CONSTEXPR_OR_CONST bool always_has_native_wait_notify = true;
74 
has_native_wait_notifyboost::atomics::detail::wait_operations_darwin_ulock_common75     static BOOST_FORCEINLINE bool has_native_wait_notify(storage_type const volatile&) BOOST_NOEXCEPT
76     {
77         return true;
78     }
79 
waitboost::atomics::detail::wait_operations_darwin_ulock_common80     static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) BOOST_NOEXCEPT
81     {
82         storage_type new_val = base_type::load(storage, order);
83         while (new_val == old_val)
84         {
85 #if defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_WAIT2)
86             __ulock_wait2(Opcode | ulock_flag_no_errno, const_cast< storage_type* >(&storage), old_val, 0u, 0u);
87 #else
88             __ulock_wait(Opcode | ulock_flag_no_errno, const_cast< storage_type* >(&storage), old_val, 0u);
89 #endif
90             new_val = base_type::load(storage, order);
91         }
92 
93         return new_val;
94     }
95 
notify_oneboost::atomics::detail::wait_operations_darwin_ulock_common96     static BOOST_FORCEINLINE void notify_one(storage_type volatile& storage) BOOST_NOEXCEPT
97     {
98         while (true)
99         {
100             const int res = __ulock_wake(Opcode | ulock_flag_no_errno, const_cast< storage_type* >(&storage), 0u);
101             if (BOOST_LIKELY(res != -EINTR))
102                 break;
103         }
104     }
105 
notify_allboost::atomics::detail::wait_operations_darwin_ulock_common106     static BOOST_FORCEINLINE void notify_all(storage_type volatile& storage) BOOST_NOEXCEPT
107     {
108         while (true)
109         {
110             const int res = __ulock_wake(Opcode | ulock_flag_wake_all | ulock_flag_no_errno, const_cast< storage_type* >(&storage), 0u);
111             if (BOOST_LIKELY(res != -EINTR))
112                 break;
113         }
114     }
115 };
116 
117 template< typename Base >
118 struct wait_operations< Base, sizeof(uint32_t), true, false > :
119     public wait_operations_darwin_ulock_common< Base, ulock_op_compare_and_wait >
120 {
121 };
122 
123 #if defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_SHARED)
124 
125 template< typename Base >
126 struct wait_operations< Base, sizeof(uint32_t), true, true > :
127     public wait_operations_darwin_ulock_common< Base, ulock_op_compare_and_wait_shared >
128 {
129 };
130 
131 #endif // defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_SHARED)
132 
133 #if defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK64)
134 
135 template< typename Base >
136 struct wait_operations< Base, sizeof(uint64_t), true, false > :
137     public wait_operations_darwin_ulock_common< Base, ulock_op_compare_and_wait64 >
138 {
139 };
140 
141 #if defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_SHARED)
142 
143 template< typename Base >
144 struct wait_operations< Base, sizeof(uint64_t), true, true > :
145     public wait_operations_darwin_ulock_common< Base, ulock_op_compare_and_wait64_shared >
146 {
147 };
148 
149 #endif // defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK_SHARED)
150 #endif // defined(BOOST_ATOMIC_DETAIL_HAS_DARWIN_ULOCK64)
151 
152 } // namespace detail
153 } // namespace atomics
154 } // namespace boost
155 
156 #include <boost/atomic/detail/footer.hpp>
157 
158 #endif // BOOST_ATOMIC_DETAIL_WAIT_OPS_DARWIN_ULOCK_HPP_INCLUDED_
159