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kernel/linux-rt-4.4.41/include/uapi/linux/membarrier.h 2.4 KB
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  #ifndef _UAPI_LINUX_MEMBARRIER_H
  #define _UAPI_LINUX_MEMBARRIER_H
  
  /*
   * linux/membarrier.h
   *
   * membarrier system call API
   *
   * Copyright (c) 2010, 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  /**
   * enum membarrier_cmd - membarrier system call command
   * @MEMBARRIER_CMD_QUERY:   Query the set of supported commands. It returns
   *                          a bitmask of valid commands.
   * @MEMBARRIER_CMD_SHARED:  Execute a memory barrier on all running threads.
   *                          Upon return from system call, the caller thread
   *                          is ensured that all running threads have passed
   *                          through a state where all memory accesses to
   *                          user-space addresses match program order between
   *                          entry to and return from the system call
   *                          (non-running threads are de facto in such a
   *                          state). This covers threads from all processes
   *                          running on the system. This command returns 0.
   *
   * Command to be passed to the membarrier system call. The commands need to
   * be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to
   * the value 0.
   */
  enum membarrier_cmd {
  	MEMBARRIER_CMD_QUERY = 0,
  	MEMBARRIER_CMD_SHARED = (1 << 0),
  };
  
  #endif /* _UAPI_LINUX_MEMBARRIER_H */