166 lines
9.2 KiB
C
166 lines
9.2 KiB
C
#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_GLOBAL: 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.
|
|
* @MEMBARRIER_CMD_GLOBAL_EXPEDITED:
|
|
* Execute a memory barrier on all running threads
|
|
* of all processes which previously registered
|
|
* with MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED.
|
|
* 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 only covers threads from processes
|
|
* which registered with
|
|
* MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED.
|
|
* This command returns 0. Given that
|
|
* registration is about the intent to receive
|
|
* the barriers, it is valid to invoke
|
|
* MEMBARRIER_CMD_GLOBAL_EXPEDITED from a
|
|
* non-registered process.
|
|
* @MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED:
|
|
* Register the process intent to receive
|
|
* MEMBARRIER_CMD_GLOBAL_EXPEDITED memory
|
|
* barriers. Always returns 0.
|
|
* @MEMBARRIER_CMD_PRIVATE_EXPEDITED:
|
|
* Execute a memory barrier on each running
|
|
* thread belonging to the same process as the current
|
|
* thread. Upon return from system call, the
|
|
* caller thread is ensured that all its running
|
|
* threads siblings 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 only covers threads from the
|
|
* same process as the caller thread. This
|
|
* command returns 0 on success. The
|
|
* "expedited" commands complete faster than
|
|
* the non-expedited ones, they never block,
|
|
* but have the downside of causing extra
|
|
* overhead. A process needs to register its
|
|
* intent to use the private expedited command
|
|
* prior to using it, otherwise this command
|
|
* returns -EPERM.
|
|
* @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED:
|
|
* Register the process intent to use
|
|
* MEMBARRIER_CMD_PRIVATE_EXPEDITED. Always
|
|
* returns 0.
|
|
* @MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE:
|
|
* In addition to provide memory ordering
|
|
* guarantees described in
|
|
* MEMBARRIER_CMD_PRIVATE_EXPEDITED, ensure
|
|
* the caller thread, upon return from system
|
|
* call, that all its running threads siblings
|
|
* have executed a core serializing
|
|
* instruction. (architectures are required to
|
|
* guarantee that non-running threads issue
|
|
* core serializing instructions before they
|
|
* resume user-space execution). This only
|
|
* covers threads from the same process as the
|
|
* caller thread. This command returns 0 on
|
|
* success. The "expedited" commands complete
|
|
* faster than the non-expedited ones, they
|
|
* never block, but have the downside of
|
|
* causing extra overhead. If this command is
|
|
* not implemented by an architecture, -EINVAL
|
|
* is returned. A process needs to register its
|
|
* intent to use the private expedited sync
|
|
* core command prior to using it, otherwise
|
|
* this command returns -EPERM.
|
|
* @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE:
|
|
* Register the process intent to use
|
|
* MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE.
|
|
* If this command is not implemented by an
|
|
* architecture, -EINVAL is returned.
|
|
* Returns 0 on success.
|
|
* @MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ:
|
|
* Ensure the caller thread, upon return from
|
|
* system call, that all its running thread
|
|
* siblings have any currently running rseq
|
|
* critical sections restarted if @flags
|
|
* parameter is 0; if @flags parameter is
|
|
* MEMBARRIER_CMD_FLAG_CPU,
|
|
* then this operation is performed only
|
|
* on CPU indicated by @cpu_id. If this command is
|
|
* not implemented by an architecture, -EINVAL
|
|
* is returned. A process needs to register its
|
|
* intent to use the private expedited rseq
|
|
* command prior to using it, otherwise
|
|
* this command returns -EPERM.
|
|
* @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ:
|
|
* Register the process intent to use
|
|
* MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ.
|
|
* If this command is not implemented by an
|
|
* architecture, -EINVAL is returned.
|
|
* Returns 0 on success.
|
|
* @MEMBARRIER_CMD_SHARED:
|
|
* Alias to MEMBARRIER_CMD_GLOBAL. Provided for
|
|
* header backward compatibility.
|
|
*
|
|
* 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_GLOBAL = (1 << 0),
|
|
MEMBARRIER_CMD_GLOBAL_EXPEDITED = (1 << 1),
|
|
MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED = (1 << 2),
|
|
MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3),
|
|
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4),
|
|
MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 5),
|
|
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 6),
|
|
MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ = (1 << 7),
|
|
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ = (1 << 8),
|
|
|
|
/* Alias for header backward compatibility. */
|
|
MEMBARRIER_CMD_SHARED = MEMBARRIER_CMD_GLOBAL,
|
|
};
|
|
|
|
enum membarrier_cmd_flag {
|
|
MEMBARRIER_CMD_FLAG_CPU = (1 << 0),
|
|
};
|
|
|
|
#endif /* _UAPI_LINUX_MEMBARRIER_H */
|