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