LXR linux/include/uapi/linux/membarrier.h

   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 */
  48enum membarrier_cmd {
  49        MEMBARRIER_CMD_QUERY = 0,
  50        MEMBARRIER_CMD_SHARED = (1 << 0),
  51};
  52
  53#endif /* _UAPI_LINUX_MEMBARRIER_H */
  54