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-rw-r--r--include/linux/sched/mm.h6
-rw-r--r--include/uapi/linux/membarrier.h42
2 files changed, 39 insertions, 9 deletions
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index b84e0fde1d72..1c4e40c5efaf 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -219,8 +219,10 @@ static inline void memalloc_noreclaim_restore(unsigned int flags)
#ifdef CONFIG_MEMBARRIER
enum {
- MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY = (1U << 0),
- MEMBARRIER_STATE_PRIVATE_EXPEDITED = (1U << 1),
+ MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY = (1U << 0),
+ MEMBARRIER_STATE_PRIVATE_EXPEDITED = (1U << 1),
+ MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY = (1U << 2),
+ MEMBARRIER_STATE_GLOBAL_EXPEDITED = (1U << 3),
};
#ifdef CONFIG_ARCH_HAS_MEMBARRIER_CALLBACKS
diff --git a/include/uapi/linux/membarrier.h b/include/uapi/linux/membarrier.h
index 4e01ad7ffe98..d252506e1b5e 100644
--- a/include/uapi/linux/membarrier.h
+++ b/include/uapi/linux/membarrier.h
@@ -31,7 +31,7 @@
* 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_SHARED: Execute a memory barrier on all running threads.
+ * @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
@@ -40,6 +40,28 @@
* (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
@@ -64,18 +86,24 @@
* Register the process intent to use
* MEMBARRIER_CMD_PRIVATE_EXPEDITED. Always
* returns 0.
+ * @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_SHARED = (1 << 0),
- /* reserved for MEMBARRIER_CMD_SHARED_EXPEDITED (1 << 1) */
- /* reserved for MEMBARRIER_CMD_PRIVATE (1 << 2) */
- MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3),
- MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4),
+ 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),
+
+ /* Alias for header backward compatibility. */
+ MEMBARRIER_CMD_SHARED = MEMBARRIER_CMD_GLOBAL,
};
#endif /* _UAPI_LINUX_MEMBARRIER_H */

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