From fafa180683591f5f917bfa68e95aae463afc852a Mon Sep 17 00:00:00 2001
From: Jonas Oberhauser <jonas.oberhauser@huaweicloud.com>
Date: Mon, 30 Sep 2024 12:57:09 +0200
Subject: tools/memory-model: Switch to softcoded herd7 tags

A new version of herd7 provides a -lkmmv2 switch which overrides the old herd7
behavior of simply ignoring any softcoded tags in the .def and .bell files. We
port LKMM to this version of herd7 by providing the switch in linux-kernel.cfg
and reporting an error if the LKMM is used without this switch.

To preserve the semantics of LKMM, we also softcode the Noreturn tag on atomic
RMW which do not return a value and define atomic_add_unless with an Mb tag in
linux-kernel.def.

We update the herd-representation.txt accordingly and clarify some of the
resulting combinations.

Co-developed-by: Hernan Ponce de Leon <hernan.poncedeleon@huaweicloud.com>
Signed-off-by: Hernan Ponce de Leon <hernan.poncedeleon@huaweicloud.com>
Signed-off-by: Jonas Oberhauser <jonas.oberhauser@huaweicloud.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Akira Yokosawa <akiyks@gmail.com> # herdtools7.7.58
---
 tools/memory-model/linux-kernel.def | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

(limited to 'tools/memory-model/linux-kernel.def')

diff --git a/tools/memory-model/linux-kernel.def b/tools/memory-model/linux-kernel.def
index a12b96c547b7..d7279a357cba 100644
--- a/tools/memory-model/linux-kernel.def
+++ b/tools/memory-model/linux-kernel.def
@@ -63,14 +63,14 @@ atomic_set(X,V) { WRITE_ONCE(*X,V); }
 atomic_read_acquire(X) smp_load_acquire(X)
 atomic_set_release(X,V) { smp_store_release(X,V); }
 
-atomic_add(V,X) { __atomic_op(X,+,V); }
-atomic_sub(V,X) { __atomic_op(X,-,V); }
-atomic_and(V,X) { __atomic_op(X,&,V); }
-atomic_or(V,X)  { __atomic_op(X,|,V); }
-atomic_xor(V,X) { __atomic_op(X,^,V); }
-atomic_inc(X)   { __atomic_op(X,+,1); }
-atomic_dec(X)   { __atomic_op(X,-,1); }
-atomic_andnot(V,X) { __atomic_op(X,&~,V); }
+atomic_add(V,X) { __atomic_op{noreturn}(X,+,V); }
+atomic_sub(V,X) { __atomic_op{noreturn}(X,-,V); }
+atomic_and(V,X) { __atomic_op{noreturn}(X,&,V); }
+atomic_or(V,X)  { __atomic_op{noreturn}(X,|,V); }
+atomic_xor(V,X) { __atomic_op{noreturn}(X,^,V); }
+atomic_inc(X)   { __atomic_op{noreturn}(X,+,1); }
+atomic_dec(X)   { __atomic_op{noreturn}(X,-,1); }
+atomic_andnot(V,X) { __atomic_op{noreturn}(X,&~,V); }
 
 atomic_add_return(V,X) __atomic_op_return{mb}(X,+,V)
 atomic_add_return_relaxed(V,X) __atomic_op_return{once}(X,+,V)
@@ -144,3 +144,5 @@ atomic_fetch_andnot(V,X) __atomic_fetch_op{mb}(X,&~,V)
 atomic_fetch_andnot_acquire(V,X) __atomic_fetch_op{acquire}(X,&~,V)
 atomic_fetch_andnot_release(V,X) __atomic_fetch_op{release}(X,&~,V)
 atomic_fetch_andnot_relaxed(V,X) __atomic_fetch_op{once}(X,&~,V)
+
+atomic_add_unless(X,V,W) __atomic_add_unless{mb}(X,V,W)
-- 
cgit v1.2.3

