[PATCH v4 2/5] tools/memory-model: Define applicable tags on operation in tools/...

[Jonas Oberhauser]

Herd7 transforms reads, writes, and read-modify-writes by eliminating
'acquire tags from writes, 'release tags from reads, and 'acquire,
'release, and 'mb tags from failed read-modify-writes. We emulate this
behavior by redefining Acquire, Release, and Mb sets in linux-kernel.bell
to explicitly exclude those combinations.

Herd7 furthermore adds 'noreturn tag to certain reads. Currently herd7
does not allow specifying the 'noreturn tag manually, but such manual
declaration (e.g., through a syntax __atomic_op{noreturn}) would add
invalid 'noreturn tags to writes; in preparation, we already also exclude
this combination.

Signed-off-by: Jonas Oberhauser <jonas.oberhauser@xxxxxxxxxxxxxxx>
---
 tools/memory-model/linux-kernel.bell | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/memory-model/linux-kernel.bell b/tools/memory-model/linux-kernel.bell
index dba6b5b6dee0..7c9ae48b9437 100644
--- a/tools/memory-model/linux-kernel.bell
+++ b/tools/memory-model/linux-kernel.bell
@@ -36,6 +36,17 @@ enum Barriers = 'wmb (*smp_wmb*) ||
 		'after-srcu-read-unlock (*smp_mb__after_srcu_read_unlock*)
 instructions F[Barriers]
 
+
+(*
+ * Filter out syntactic annotations that do not provide the corresponding
+ * semantic ordering, such as Acquire on a store or Mb on a failed RMW.
+ *)
+let FailedRMW = RMW \ (domain(rmw) | range(rmw))
+let Acquire = Acquire \ W \ FailedRMW
+let Release = Release \ R \ FailedRMW
+let Mb = Mb \ FailedRMW
+let Noreturn = Noreturn \ W
+
 (* SRCU *)
 enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu
 instructions SRCU[SRCU]
-- 
2.34.1