82 lines
4.1 KiB
C
82 lines
4.1 KiB
C
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#ifndef _UAPI_LINUX_MEMBARRIER_H
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#define _UAPI_LINUX_MEMBARRIER_H
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/*
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* linux/membarrier.h
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*
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* membarrier system call API
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*
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* Copyright (c) 2010, 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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/**
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* enum membarrier_cmd - membarrier system call command
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* @MEMBARRIER_CMD_QUERY: Query the set of supported commands. It returns
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* a bitmask of valid commands.
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* @MEMBARRIER_CMD_SHARED: Execute a memory barrier on all running threads.
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* Upon return from system call, the caller thread
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* is ensured that all running threads have passed
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* through a state where all memory accesses to
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* user-space addresses match program order between
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* entry to and return from the system call
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* (non-running threads are de facto in such a
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* state). This covers threads from all processes
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* running on the system. This command returns 0.
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* @MEMBARRIER_CMD_PRIVATE_EXPEDITED:
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* Execute a memory barrier on each running
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* thread belonging to the same process as the current
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* thread. Upon return from system call, the
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* caller thread is ensured that all its running
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* threads siblings have passed through a state
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* where all memory accesses to user-space
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* addresses match program order between entry
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* to and return from the system call
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* (non-running threads are de facto in such a
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* state). This only covers threads from the
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* same processes as the caller thread. This
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* command returns 0 on success. The
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* "expedited" commands complete faster than
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* the non-expedited ones, they never block,
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* but have the downside of causing extra
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* overhead. A process needs to register its
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* intent to use the private expedited command
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* prior to using it, otherwise this command
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* returns -EPERM.
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* @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED:
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* Register the process intent to use
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* MEMBARRIER_CMD_PRIVATE_EXPEDITED. Always
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* returns 0.
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*
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* Command to be passed to the membarrier system call. The commands need to
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* be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to
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* the value 0.
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*/
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enum membarrier_cmd {
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MEMBARRIER_CMD_QUERY = 0,
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MEMBARRIER_CMD_SHARED = (1 << 0),
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/* reserved for MEMBARRIER_CMD_SHARED_EXPEDITED (1 << 1) */
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/* reserved for MEMBARRIER_CMD_PRIVATE (1 << 2) */
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MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3),
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MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4),
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};
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#endif /* _UAPI_LINUX_MEMBARRIER_H */
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