1 #ifndef _UAPI_LINUX_MEMBARRIER_H 1 #ifndef _UAPI_LINUX_MEMBARRIER_H
2 #define _UAPI_LINUX_MEMBARRIER_H 2 #define _UAPI_LINUX_MEMBARRIER_H
3 3
4 /* 4 /*
5 * linux/membarrier.h 5 * linux/membarrier.h
6 * 6 *
7 * membarrier system call API 7 * membarrier system call API
8 * 8 *
9 * Copyright (c) 2010, 2015 Mathieu Desnoyers 9 * Copyright (c) 2010, 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 * 10 *
11 * Permission is hereby granted, free of charg 11 * Permission is hereby granted, free of charge, to any person obtaining a copy
12 * of this software and associated documentati 12 * of this software and associated documentation files (the "Software"), to deal
13 * in the Software without restriction, includ 13 * in the Software without restriction, including without limitation the rights
14 * to use, copy, modify, merge, publish, distr 14 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
15 * copies of the Software, and to permit perso 15 * copies of the Software, and to permit persons to whom the Software is
16 * furnished to do so, subject to the followin 16 * furnished to do so, subject to the following conditions:
17 * 17 *
18 * The above copyright notice and this permiss 18 * The above copyright notice and this permission notice shall be included in
19 * all copies or substantial portions of the S 19 * all copies or substantial portions of the Software.
20 * 20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT W 21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE W 22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINF 23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
24 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 24 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT 25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
26 * OUT OF OR IN CONNECTION WITH THE SOFTWARE O 26 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
27 * SOFTWARE. 27 * SOFTWARE.
28 */ 28 */
29 29
30 /** 30 /**
31 * enum membarrier_cmd - membarrier system cal 31 * enum membarrier_cmd - membarrier system call command
32 * @MEMBARRIER_CMD_QUERY: Query the set of s 32 * @MEMBARRIER_CMD_QUERY: Query the set of supported commands. It returns
33 * a bitmask of valid 33 * a bitmask of valid commands.
34 * @MEMBARRIER_CMD_GLOBAL: Execute a memory b 34 * @MEMBARRIER_CMD_GLOBAL: Execute a memory barrier on all running threads.
35 * Upon return from s 35 * Upon return from system call, the caller thread
36 * is ensured that al 36 * is ensured that all running threads have passed
37 * through a state wh 37 * through a state where all memory accesses to
38 * user-space address 38 * user-space addresses match program order between
39 * entry to and retur 39 * entry to and return from the system call
40 * (non-running threa 40 * (non-running threads are de facto in such a
41 * state). This cover 41 * state). This covers threads from all processes
42 * running on the sys 42 * running on the system. This command returns 0.
43 * @MEMBARRIER_CMD_GLOBAL_EXPEDITED: 43 * @MEMBARRIER_CMD_GLOBAL_EXPEDITED:
44 * Execute a memory b 44 * Execute a memory barrier on all running threads
45 * of all processes w 45 * of all processes which previously registered
46 * with MEMBARRIER_CM 46 * with MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED.
47 * Upon return from s 47 * Upon return from system call, the caller thread
48 * is ensured that al 48 * is ensured that all running threads have passed
49 * through a state wh 49 * through a state where all memory accesses to
50 * user-space address 50 * user-space addresses match program order between
51 * entry to and retur 51 * entry to and return from the system call
52 * (non-running threa 52 * (non-running threads are de facto in such a
53 * state). This only 53 * state). This only covers threads from processes
54 * which registered w 54 * which registered with
55 * MEMBARRIER_CMD_REG 55 * MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED.
56 * This command retur 56 * This command returns 0. Given that
57 * registration is ab 57 * registration is about the intent to receive
58 * the barriers, it i 58 * the barriers, it is valid to invoke
59 * MEMBARRIER_CMD_GLO 59 * MEMBARRIER_CMD_GLOBAL_EXPEDITED from a
60 * non-registered pro 60 * non-registered process.
61 * @MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED: 61 * @MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED:
62 * Register the proce 62 * Register the process intent to receive
63 * MEMBARRIER_CMD_GLO 63 * MEMBARRIER_CMD_GLOBAL_EXPEDITED memory
64 * barriers. Always r 64 * barriers. Always returns 0.
65 * @MEMBARRIER_CMD_PRIVATE_EXPEDITED: 65 * @MEMBARRIER_CMD_PRIVATE_EXPEDITED:
66 * Execute a memory b 66 * Execute a memory barrier on each running
67 * thread belonging t 67 * thread belonging to the same process as the current
68 * thread. Upon retur 68 * thread. Upon return from system call, the
69 * caller thread is e 69 * caller thread is ensured that all its running
70 * threads siblings h 70 * threads siblings have passed through a state
71 * where all memory a 71 * where all memory accesses to user-space
72 * addresses match pr 72 * addresses match program order between entry
73 * to and return from 73 * to and return from the system call
74 * (non-running threa 74 * (non-running threads are de facto in such a
75 * state). This only 75 * state). This only covers threads from the
76 * same process as th 76 * same process as the caller thread. This
77 * command returns 0 77 * command returns 0 on success. The
78 * "expedited" comman 78 * "expedited" commands complete faster than
79 * the non-expedited 79 * the non-expedited ones, they never block,
80 * but have the downs 80 * but have the downside of causing extra
81 * overhead. A proces 81 * overhead. A process needs to register its
82 * intent to use the 82 * intent to use the private expedited command
83 * prior to using it, 83 * prior to using it, otherwise this command
84 * returns -EPERM. 84 * returns -EPERM.
85 * @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED: 85 * @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED:
86 * Register the proce 86 * Register the process intent to use
87 * MEMBARRIER_CMD_PRI 87 * MEMBARRIER_CMD_PRIVATE_EXPEDITED. Always
88 * returns 0. 88 * returns 0.
89 * @MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE 89 * @MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE:
90 * In addition to pro 90 * In addition to provide memory ordering
91 * guarantees describ 91 * guarantees described in
92 * MEMBARRIER_CMD_PRI 92 * MEMBARRIER_CMD_PRIVATE_EXPEDITED, ensure
93 * the caller thread, 93 * the caller thread, upon return from system
94 * call, that all its 94 * call, that all its running threads siblings
95 * have executed a co 95 * have executed a core serializing
96 * instruction. (arch 96 * instruction. (architectures are required to
97 * guarantee that non 97 * guarantee that non-running threads issue
98 * core serializing i 98 * core serializing instructions before they
99 * resume user-space 99 * resume user-space execution). This only
100 * covers threads fro 100 * covers threads from the same process as the
101 * caller thread. Thi 101 * caller thread. This command returns 0 on
102 * success. The "expe 102 * success. The "expedited" commands complete
103 * faster than the no 103 * faster than the non-expedited ones, they
104 * never block, but h 104 * never block, but have the downside of
105 * causing extra over 105 * causing extra overhead. If this command is
106 * not implemented by 106 * not implemented by an architecture, -EINVAL
107 * is returned. A pro 107 * is returned. A process needs to register its
108 * intent to use the 108 * intent to use the private expedited sync
109 * core command prior 109 * core command prior to using it, otherwise
110 * this command retur 110 * this command returns -EPERM.
111 * @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_ 111 * @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE:
112 * Register the proce 112 * Register the process intent to use
113 * MEMBARRIER_CMD_PRI 113 * MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE.
114 * If this command is 114 * If this command is not implemented by an
115 * architecture, -EIN 115 * architecture, -EINVAL is returned.
116 * Returns 0 on succe 116 * Returns 0 on success.
117 * @MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ: 117 * @MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ:
118 * Ensure the caller 118 * Ensure the caller thread, upon return from
119 * system call, that 119 * system call, that all its running thread
120 * siblings have any 120 * siblings have any currently running rseq
121 * critical sections 121 * critical sections restarted if @flags
122 * parameter is 0; if 122 * parameter is 0; if @flags parameter is
123 * MEMBARRIER_CMD_FLA 123 * MEMBARRIER_CMD_FLAG_CPU,
124 * then this operatio 124 * then this operation is performed only
125 * on CPU indicated b 125 * on CPU indicated by @cpu_id. If this command is
126 * not implemented by 126 * not implemented by an architecture, -EINVAL
127 * is returned. A pro 127 * is returned. A process needs to register its
128 * intent to use the 128 * intent to use the private expedited rseq
129 * command prior to u 129 * command prior to using it, otherwise
130 * this command retur 130 * this command returns -EPERM.
131 * @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_ 131 * @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ:
132 * Register the proce 132 * Register the process intent to use
133 * MEMBARRIER_CMD_PRI 133 * MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ.
134 * If this command is 134 * If this command is not implemented by an
135 * architecture, -EIN 135 * architecture, -EINVAL is returned.
136 * Returns 0 on succe 136 * Returns 0 on success.
137 * @MEMBARRIER_CMD_SHARED: 137 * @MEMBARRIER_CMD_SHARED:
138 * Alias to MEMBARRIE 138 * Alias to MEMBARRIER_CMD_GLOBAL. Provided for
139 * header backward co 139 * header backward compatibility.
140 * @MEMBARRIER_CMD_GET_REGISTRATIONS: 140 * @MEMBARRIER_CMD_GET_REGISTRATIONS:
141 * Returns a bitmask 141 * Returns a bitmask of previously issued
142 * registration comma 142 * registration commands.
143 * 143 *
144 * Command to be passed to the membarrier syst 144 * Command to be passed to the membarrier system call. The commands need to
145 * be a single bit each, except for MEMBARRIER 145 * be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to
146 * the value 0. 146 * the value 0.
147 */ 147 */
148 enum membarrier_cmd { 148 enum membarrier_cmd {
149 MEMBARRIER_CMD_QUERY 149 MEMBARRIER_CMD_QUERY = 0,
150 MEMBARRIER_CMD_GLOBAL 150 MEMBARRIER_CMD_GLOBAL = (1 << 0),
151 MEMBARRIER_CMD_GLOBAL_EXPEDITED 151 MEMBARRIER_CMD_GLOBAL_EXPEDITED = (1 << 1),
152 MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDIT 152 MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED = (1 << 2),
153 MEMBARRIER_CMD_PRIVATE_EXPEDITED 153 MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3),
154 MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDI 154 MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4),
155 MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_ 155 MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 5),
156 MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDI 156 MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 6),
157 MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ 157 MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ = (1 << 7),
158 MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDI 158 MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ = (1 << 8),
159 MEMBARRIER_CMD_GET_REGISTRATIONS 159 MEMBARRIER_CMD_GET_REGISTRATIONS = (1 << 9),
160 160
161 /* Alias for header backward compatibi 161 /* Alias for header backward compatibility. */
162 MEMBARRIER_CMD_SHARED 162 MEMBARRIER_CMD_SHARED = MEMBARRIER_CMD_GLOBAL,
163 }; 163 };
164 164
165 enum membarrier_cmd_flag { 165 enum membarrier_cmd_flag {
166 MEMBARRIER_CMD_FLAG_CPU = (1 < 166 MEMBARRIER_CMD_FLAG_CPU = (1 << 0),
167 }; 167 };
168 168
169 #endif /* _UAPI_LINUX_MEMBARRIER_H */ 169 #endif /* _UAPI_LINUX_MEMBARRIER_H */
170 170
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