| #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 */ |