| #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_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), |
| |
| /* Alias for header backward compatibility. */ |
| MEMBARRIER_CMD_SHARED = MEMBARRIER_CMD_GLOBAL, |
| }; |
| |
| #endif /* _UAPI_LINUX_MEMBARRIER_H */ |
