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