]>
Commit | Line | Data |
---|---|---|
5b25b13a MD |
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_SHARED: 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. | |
22e4ebb9 MD |
43 | * @MEMBARRIER_CMD_PRIVATE_EXPEDITED: |
44 | * Execute a memory barrier on each running | |
45 | * thread belonging to the same process as the current | |
46 | * thread. Upon return from system call, the | |
47 | * caller thread is ensured that all its running | |
48 | * threads siblings have passed through a state | |
49 | * where all memory accesses to user-space | |
50 | * addresses match program order between entry | |
51 | * to and return from the system call | |
52 | * (non-running threads are de facto in such a | |
53 | * state). This only covers threads from the | |
54 | * same processes as the caller thread. This | |
a961e409 MD |
55 | * command returns 0 on success. The |
56 | * "expedited" commands complete faster than | |
57 | * the non-expedited ones, they never block, | |
58 | * but have the downside of causing extra | |
59 | * overhead. A process needs to register its | |
60 | * intent to use the private expedited command | |
61 | * prior to using it, otherwise this command | |
62 | * returns -EPERM. | |
63 | * @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED: | |
64 | * Register the process intent to use | |
65 | * MEMBARRIER_CMD_PRIVATE_EXPEDITED. Always | |
66 | * returns 0. | |
5b25b13a MD |
67 | * |
68 | * Command to be passed to the membarrier system call. The commands need to | |
69 | * be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to | |
70 | * the value 0. | |
71 | */ | |
72 | enum membarrier_cmd { | |
a961e409 MD |
73 | MEMBARRIER_CMD_QUERY = 0, |
74 | MEMBARRIER_CMD_SHARED = (1 << 0), | |
22e4ebb9 MD |
75 | /* reserved for MEMBARRIER_CMD_SHARED_EXPEDITED (1 << 1) */ |
76 | /* reserved for MEMBARRIER_CMD_PRIVATE (1 << 2) */ | |
a961e409 MD |
77 | MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3), |
78 | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4), | |
5b25b13a MD |
79 | }; |
80 | ||
81 | #endif /* _UAPI_LINUX_MEMBARRIER_H */ |