From nobody Tue Dec 16 13:22:06 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E1853211292; Thu, 20 Feb 2025 16:14:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740068046; cv=none; b=rd0irdzcPMmqJmXu0bPEWik3ewelOBARXI3j34mn/Ow0sS5CHA+5cyESh1BMH7g7svzqdSUHdfRMSAzeBEmB/DzL16bQQT1ukxY8qoNh3JKVxDspgnzpiBdVrG4XdVwcnXaudLEv+I1Cac+DdtapEqR912mhlSR7ECLYGZLsDIw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740068046; c=relaxed/simple; bh=TsvXbj8pt31jepIWyXRjFgkBXvYwvZCcef75PEq5V2U=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hG9ZKzBAunYhW7AtJW/D5dHntEZ5TanB4XBpKpOmOTcunY3j2UDzH+PsjQ58ed+XjbF4kqAJVohynicaQJ7/81vQGDyVpLFUrBGkfrVXOXZBAMFu65L3hAe92L9zPAv4z0iSCBGuBtU2UNkC/Ls9WnWeUn61OrA9UAtPaqAMYl8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WlBavuS7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WlBavuS7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A7F8C4CEF4; Thu, 20 Feb 2025 16:14:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740068045; bh=TsvXbj8pt31jepIWyXRjFgkBXvYwvZCcef75PEq5V2U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WlBavuS7Pm6ZbqBJFTktu4nmnnkmz+raAO0fuJW4NlW1+olnLq444kyKFyiOpLeVn ask3aK6su4JZlVdgpDNGZg3DZBa0XuzGwB+v+xuSr1B57Ji5KwDQCWkvv/uDR9xEf4 tcRt1Lb1iX3fk6wRlW6Nb1n2rRRr115ZRoKeEyMxH3Yzd19oQUooY23cENPWJV7Qkl xhkionvIAl2QO6NY/aZo3b116xEuG1Fi6uOwIqRbBGdYunZ3VmMwRaJ+ysNflJPKMQ h6kC08r0C2rjoSR3uD7VtTLNT9PO9HTHLdc8LpReVfI8akMSDowrmKlmjR6V+jpbng hFsFGzWuMpd+A== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id ACFEFCE0D8A; Thu, 20 Feb 2025 08:14:04 -0800 (PST) From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, lkmm@lists.linux.dev, kernel-team@meta.com, mingo@kernel.org Cc: stern@rowland.harvard.edu, parri.andrea@gmail.com, will@kernel.org, peterz@infradead.org, boqun.feng@gmail.com, npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk, luc.maranget@inria.fr, akiyks@gmail.com, Jonas Oberhauser , Hernan Ponce de Leon , "Paul E . McKenney" Subject: [PATCH memory-model 6/7] tools/memory-model: Switch to softcoded herd7 tags Date: Thu, 20 Feb 2025 08:14:02 -0800 Message-Id: <20250220161403.800831-6-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <8cfb51e3-9726-4285-b8ca-0d0abcacb07e@paulmck-laptop> References: <8cfb51e3-9726-4285-b8ca-0d0abcacb07e@paulmck-laptop> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Jonas Oberhauser A new version of herd7 provides a -lkmmv2 switch which overrides the old he= rd7 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 ato= mic 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. Signed-off-by: Hernan Ponce de Leon Signed-off-by: Jonas Oberhauser Signed-off-by: Paul E. McKenney Reviewed-by: Boqun Feng Tested-by: Boqun Feng Tested-by: Akira Yokosawa # herdtools7.7.58 --- .../Documentation/herd-representation.txt | 27 ++++++++++--------- tools/memory-model/README | 2 +- tools/memory-model/linux-kernel.bell | 3 +++ tools/memory-model/linux-kernel.cfg | 1 + tools/memory-model/linux-kernel.def | 18 +++++++------ 5 files changed, 30 insertions(+), 21 deletions(-) diff --git a/tools/memory-model/Documentation/herd-representation.txt b/too= ls/memory-model/Documentation/herd-representation.txt index ed988906f2b71..7ae1ff3d3769e 100644 --- a/tools/memory-model/Documentation/herd-representation.txt +++ b/tools/memory-model/Documentation/herd-representation.txt @@ -18,6 +18,11 @@ # # By convention, a blank line in a cell means "same as the preceding line". # +# Note that the syntactic representation does not always match the sets and +# relations in linux-kernel.cat, due to redefinitions in linux-kernel.bell= and +# lock.cat. For example, the po link between LKR and LKW is upgraded to an= rmw +# link, and W[acquire] are not included in the Acquire set. +# # Disclaimer. The table includes representations of "add" and "and" opera= tions; # corresponding/identical representations of "sub", "inc", "dec" and "or",= "xor", # "andnot" operations are omitted. @@ -60,14 +65,13 @@ ----------------------------------------------------------------------= -------- | RMW ops w/o return value | = | ----------------------------------------------------------------------= -------- - | atomic_add | R*[noreturn] ->rmw W*[once] = | + | atomic_add | R*[noreturn] ->rmw W*[noreturn] = | | atomic_and | = | | spin_lock | LKR ->po LKW = | ----------------------------------------------------------------------= -------- | RMW ops w/ return value | = | ----------------------------------------------------------------------= -------- - | atomic_add_return | F[mb] ->po R*[once] = | - | | ->rmw W*[once] ->po F[mb] = | + | atomic_add_return | R*[mb] ->rmw W*[mb] = | | atomic_fetch_add | = | | atomic_fetch_and | = | | atomic_xchg | = | @@ -79,13 +83,13 @@ | atomic_xchg_relaxed | = | | xchg_relaxed | = | | atomic_add_negative_relaxed | = | - | atomic_add_return_acquire | R*[acquire] ->rmw W*[once] = | + | atomic_add_return_acquire | R*[acquire] ->rmw W*[acquire] = | | atomic_fetch_add_acquire | = | | atomic_fetch_and_acquire | = | | atomic_xchg_acquire | = | | xchg_acquire | = | | atomic_add_negative_acquire | = | - | atomic_add_return_release | R*[once] ->rmw W*[release] = | + | atomic_add_return_release | R*[release] ->rmw W*[release] = | | atomic_fetch_add_release | = | | atomic_fetch_and_release | = | | atomic_xchg_release | = | @@ -94,17 +98,16 @@ ----------------------------------------------------------------------= -------- | Conditional RMW ops | = | ----------------------------------------------------------------------= -------- - | atomic_cmpxchg | On success: F[mb] ->po R*[once] = | - | | ->rmw W*[once] ->po= F[mb] | - | | On failure: R*[once] = | + | atomic_cmpxchg | On success: R*[mb] ->rmw W*[mb] = | + | | On failure: R*[mb] = | | cmpxchg | = | | atomic_add_unless | = | | atomic_cmpxchg_relaxed | On success: R*[once] ->rmw W*[once]= | | | On failure: R*[once] = | - | atomic_cmpxchg_acquire | On success: R*[acquire] ->rmw W*[on= ce] | - | | On failure: R*[once] = | - | atomic_cmpxchg_release | On success: R*[once] ->rmw W*[relea= se] | - | | On failure: R*[once] = | + | atomic_cmpxchg_acquire | On success: R*[acquire] ->rmw W*[ac= quire] | + | | On failure: R*[acquire] = | + | atomic_cmpxchg_release | On success: R*[release] ->rmw W*[re= lease] | + | | On failure: R*[release] = | | spin_trylock | On success: LKR ->po LKW = | | | On failure: LF = | ----------------------------------------------------------------------= -------- diff --git a/tools/memory-model/README b/tools/memory-model/README index dab38904206a0..59bc15edeb8ab 100644 --- a/tools/memory-model/README +++ b/tools/memory-model/README @@ -20,7 +20,7 @@ that litmus test to be exercised within the Linux kernel. REQUIREMENTS =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 -Version 7.52 or higher of the "herd7" and "klitmus7" tools must be +Version 7.58 or higher of the "herd7" and "klitmus7" tools must be downloaded separately: =20 https://github.com/herd/herdtools7 diff --git a/tools/memory-model/linux-kernel.bell b/tools/memory-model/linu= x-kernel.bell index 7c9ae48b94377..8ae47545df978 100644 --- a/tools/memory-model/linux-kernel.bell +++ b/tools/memory-model/linux-kernel.bell @@ -94,3 +94,6 @@ let carry-dep =3D (data ; [~ Srcu-unlock] ; rfi)* let addr =3D carry-dep ; addr let ctrl =3D carry-dep ; ctrl let data =3D carry-dep ; data + +flag ~empty (if "lkmmv2" then 0 else _) + as this-model-requires-variant-higher-than-lkmmv1 diff --git a/tools/memory-model/linux-kernel.cfg b/tools/memory-model/linux= -kernel.cfg index 3c8098e99f41d..69b04f3aad737 100644 --- a/tools/memory-model/linux-kernel.cfg +++ b/tools/memory-model/linux-kernel.cfg @@ -1,6 +1,7 @@ macros linux-kernel.def bell linux-kernel.bell model linux-kernel.cat +variant lkmmv2 graph columns squished true showevents noregs diff --git a/tools/memory-model/linux-kernel.def b/tools/memory-model/linux= -kernel.def index a12b96c547b7a..d7279a357cba0 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); } =20 -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); } =20 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) --=20 2.40.1