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 <[email protected]>
---
tools/memory-model/linux-kernel.bell | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/tools/memory-model/linux-kernel.bell b/tools/memory-model/linux-kernel.bell
index 1b2444cdf8d1..08fa1ccb1328 100644
--- a/tools/memory-model/linux-kernel.bell
+++ b/tools/memory-model/linux-kernel.bell
@@ -36,6 +36,13 @@ enum Barriers = 'wmb (*smp_wmb*) ||
'after-srcu-read-unlock (*smp_mb__after_srcu_read_unlock*)
instructions F[Barriers]
+(* Remove impossible tags, such as Acquire on a store or 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]
@@ -82,4 +89,4 @@ let Plain = M \ Marked
let carry-dep = (data ; [~ Srcu-unlock] ; rfi)*
let addr = carry-dep ; addr
let ctrl = carry-dep ; ctrl
-let data = carry-dep ; data
+let data = carry-dep ; data
\ No newline at end of file
--
2.34.1
On Mon, May 27, 2024 at 05:22:51PM +0200, Jonas Oberhauser wrote:
> 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 <[email protected]>
> ---
> tools/memory-model/linux-kernel.bell | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/tools/memory-model/linux-kernel.bell b/tools/memory-model/linux-kernel.bell
> index 1b2444cdf8d1..08fa1ccb1328 100644
> --- a/tools/memory-model/linux-kernel.bell
> +++ b/tools/memory-model/linux-kernel.bell
> @@ -36,6 +36,13 @@ enum Barriers = 'wmb (*smp_wmb*) ||
> 'after-srcu-read-unlock (*smp_mb__after_srcu_read_unlock*)
> instructions F[Barriers]
>
> +(* Remove impossible tags, such as Acquire on a store or 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]
> @@ -82,4 +89,4 @@ let Plain = M \ Marked
> let carry-dep = (data ; [~ Srcu-unlock] ; rfi)*
> let addr = carry-dep ; addr
> let ctrl = carry-dep ; ctrl
> -let data = carry-dep ; data
> +let data = carry-dep ; data
> \ No newline at end of file
It looks like the final newline was accidentally deleted.
Alan