sched/membarrier: Fix membarrier-rseq fence command missing from query bitmask

BugLink: https://bugs.launchpad.net/bugs/1959879
commit 809232619f5b15e31fb3563985e705454f32621f upstream.

The membarrier command MEMBARRIER_CMD_QUERY allows querying the
available membarrier commands. When the membarrier-rseq fence commands
were added, a new MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ_BITMASK was
introduced with the intent to expose them with the MEMBARRIER_CMD_QUERY
command, the but it was never added to MEMBARRIER_CMD_BITMASK.

The membarrier-rseq fence commands are therefore not wired up with the
query command.

Rename MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ_BITMASK to
MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK (the bitmask is not a command
per-se), and change the erroneous
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ_BITMASK (which does not
actually exist) to MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ.

Wire up MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK in
MEMBARRIER_CMD_BITMASK. Fixing this allows discovering availability of
the membarrier-rseq fence feature.

Fixes: 2a36ab717e8f ("rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # 5.10+
Link: https://lkml.kernel.org/r/20220117203010.30129-1-mathieu.desnoyers@efficios.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
index b5add64d9698c60813f6640d0c6a3e944f21aba1..3d2825408e3a2544fd19ace94839d8ed34e20929 100644 (file)
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -147,11 +147,11 @@
 #endif
 
 #ifdef CONFIG_RSEQ
-#define MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ_BITMASK          \
+#define MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK              \
        (MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ                  \
-       | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ_BITMASK)
+       | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ)
 #else
-#define MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ_BITMASK  0
+#define MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK      0
 #endif
 
 #define MEMBARRIER_CMD_BITMASK                                         \
@@ -159,7 +159,8 @@
        | MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED                      \
        | MEMBARRIER_CMD_PRIVATE_EXPEDITED                              \
        | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED                     \
-       | MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK)
+       | MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK                \
+       | MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK)
 
 static void ipi_mb(void *info)
 {