From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-op-o15.zoho.com (sender4-op-o15.zoho.com [136.143.188.15]) (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 3BD8A2222B2; Thu, 19 Feb 2026 08:05:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.15 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771488324; cv=pass; b=glFkp3Luc+2h3AV2OSEsDiR6u6/zzqpj7j1fz9x7U4m8x7uZkilVKhWRk5QxgAK+JU4zM3OYeUo30p3MI2wx+/yO6WrZNY43y51QRNVsRL27RoT5BTgjPdGteupxiQOcJF6CnPZONaY1FKlGHuO4Ry7qeAr1fRgN6zfr/+KCNE0= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771488324; c=relaxed/simple; bh=mZ1okY8wh3/E7KclMIJhob/eOJu2zzwpAoIKVt+HodI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UeH4LLYuRTSc58ogxW8YPNcf/ODMeg1ejviqbav6r8mcopQgrfnPTSzMjYbcmUaoER9ka9n7kPfa/gCKXHD0Eof1uLyzDmUDbhahuL6g54EH5QUomURJs5l5AOMrd+jASumGewFFYJePT1piZIGrBtC0doYIyfLoY1UCJNSiM48= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ziyao.cc; spf=pass smtp.mailfrom=ziyao.cc; dkim=pass (1024-bit key) header.d=ziyao.cc header.i=me@ziyao.cc header.b=QevocWd9; arc=pass smtp.client-ip=136.143.188.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ziyao.cc Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziyao.cc Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ziyao.cc header.i=me@ziyao.cc header.b="QevocWd9" ARC-Seal: i=1; a=rsa-sha256; t=1771488293; cv=none; d=zohomail.com; s=zohoarc; b=ikjtOb3oX1EgHtdw2QAxqKYlVneQSwVpL0ucVwHo2BOn3HB/94myWhKMGQINXwdpOZK3npc4LWXT0YMSrQirMOoIz+sEXFjEdql88wfXp64KGkhIeNFuy7DLDj9rvmm2PWm5g2SNYv/JXH3pBME1YFe7gkhQJ6g4f2N7Z6ohgeM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1771488293; h=Content-Type:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=kYQ5NkddKGLVG7KXnc5tVWiA8oqeInGD+WTRnEtYdQ0=; b=ca1PRjshbgl0kblWXlxZYjxLz4+EjGHd7r3vw5HoWB6wxiDrLsM3QC5vaKvKz7Clyg5R1kKeapY94Kb4FWBEyZbGPhhgYGjlOgmQXF9gU2aPZ0B26sB778xsKw693Dk8mkTwyV8ivBeFNMZc7EYzJJ10UxCBdOWLTdQ+Sh0piFk= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=ziyao.cc; spf=pass smtp.mailfrom=me@ziyao.cc; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1771488293; s=zmail; d=ziyao.cc; i=me@ziyao.cc; h=Date:Date:From:From:To:To:Cc:Cc:Subject:Subject:Message-ID:References:MIME-Version:Content-Type:In-Reply-To:Message-Id:Reply-To; bh=kYQ5NkddKGLVG7KXnc5tVWiA8oqeInGD+WTRnEtYdQ0=; b=QevocWd9wnFpbz6v8KCBM++Ys6nV8e156lzrioDP5AuZwNKDcNaawITAAg98QsGk Kb2uKNno6Tg11FVRfVCyTILiEQN1MdAM79iW7HpvdQ+22Qf+5kenHshvDOppuegxWjr 7d1YgfTJOZuj6xEGdtMUB56dClW92AivaTYOIfLU= Received: by mx.zohomail.com with SMTPS id 1771488291848192.88439580319414; Thu, 19 Feb 2026 00:04:51 -0800 (PST) Date: Thu, 19 Feb 2026 08:04:42 +0000 From: Yao Zi To: guoren@kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, alex@ghiti.fr, leobras@redhat.com, djordje.todorovic@htecgroup.com, aleksa.paunovic@htecgroup.com, arnd@arndb.de, rabenda.cn@gmail.com Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Han Gao , Alexandre Ghiti , Paul Walmsley Subject: Re: [PATCH V3] riscv: errata: Add ERRATA_THEAD_WRITE_ONCE fixup Message-ID: References: <20260125063941.443777-1-guoren@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260125063941.443777-1-guoren@kernel.org> X-ZohoMailClient: External On Sun, Jan 25, 2026 at 01:39:41AM -0500, guoren@kernel.org wrote: > From: "Guo Ren (Alibaba DAMO Academy)" > > The early version of XuanTie C910 core has a store merge buffer > delay problem. The store merge buffer could improve the store queue > performance by merging multi-store requests, but when there are not > continued store requests, the prior single store request would be > waiting in the store queue for a long time. That would cause > significant problems for communication between multi-cores. This > problem was found on sg2042 & th1520 platforms with the qspinlock > lock torture test. > > So appending a fence w.o could immediately flush the store merge > buffer and let other cores see the write result. > > This will apply the WRITE_ONCE errata to handle the non-standard > behavior via appending a fence w.o instruction for WRITE_ONCE(). > > This problem is only observed on the sg2042 hardware platform by > running the lock_torture test program for half an hour. The problem > was not found in the user space application, because interrupt can > break the livelock. > > Reviewed-by: Leonardo Bras > Tested-by: Han Gao > Cc: Yao Zi > Cc: Alexandre Ghiti > Cc: Paul Walmsley > Signed-off-by: Guo Ren (Alibaba DAMO Academy) With the patch, I've run heavy multi-core compilation load on SG2042 for more than 12 hours, and observed no stability issues. Tested-by: Yao Zi Thanks, Yao Zi