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. 43 * 44 * Command to be passed to the membarrier system call. The commands need to 45 * be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to 46 * the value 0. 47 */ 48 enum membarrier_cmd { 49 MEMBARRIER_CMD_QUERY = 0, 50 MEMBARRIER_CMD_SHARED = (1 << 0), 51 }; 52 53 #endif /* _UAPI_LINUX_MEMBARRIER_H */ 54