From mboxrd@z Thu Jan 1 00:00:00 1970 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 9013423E350; Fri, 23 Jan 2026 17:50:07 +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=1769190607; cv=none; b=T+YZTH2QyvzhLKJhaXCLQt1HqTE86qT+6xkJa0kSRqr/enCPvRvdMO6kORVOhfU6AbJw+oCfKSLXUPWB5prlvEMcsGkVmDzwhJ2ge4AFrqE1/r0ZUPhZr8egz4NoHa5jDm5vzjQg3g3z+d0LEcLagPUcfLB01UXXh0dNYM5E4qQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769190607; c=relaxed/simple; bh=pNDw2hoRSoUTdVAMzmKFR2iLJdLsJKYyv1Q6f1ot0x4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=tT4oZhd6GRWWtaDt/8XIhv0djslmqIFQiBs4YeRA6yGJpCz5cTuu63cWPBFAoC0SFRUWb8a+dDEN0ng5VINvfrXbYlSFtqNYL8OGdL2/brd2H88immw5TDvEKTBDv43392umHO81psEpyy7sBVfHMzYwYUEVJ3RxQhi3gnDqNXw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KSkobJ1P; 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="KSkobJ1P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40610C19424; Fri, 23 Jan 2026 17:50:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769190607; bh=pNDw2hoRSoUTdVAMzmKFR2iLJdLsJKYyv1Q6f1ot0x4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KSkobJ1PuDzl3BZW/6RSLzYhStZSQ2v5BISMF3Dz08or/CD1gwUKeWQGFmIYzWCr5 Faqs+7shujGbSQbvR0V2ly0H5qUprgjZ4Doi5O2+dM9Ir8aM5dJzRMDtANzg+HF+O6 VqMFaxuOvdBPTHckF5me8lSkWHZpu9ReDkrKz3iZy0cdBoxw8CxoZ2LhaOmREtJt7w LJRaOdqdda/ipGe1fOATg0t/GGPgn+pC0OtyEOQ279BS+HZaWvYcS8PTjD2Com46we P2T8N0ak/SPu0vKV2nD90rxyxIdhGEQerzri00u02HaqhPD6U922FJZSVJuiprYCEB H8EpDzztgVSmw== From: Will Deacon To: Catalin Marinas , Jonathan Corbet , Lucas Wei Cc: kernel-team@android.com, Will Deacon , sjadavani@google.com, stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] arm64: errata: Workaround for SI L1 downstream coherency issue Date: Fri, 23 Jan 2026 17:49:49 +0000 Message-ID: <176917501918.797415.179034767474498162.b4-ty@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260114145243.3458315-1-lucaswei@google.com> References: <20260114145243.3458315-1-lucaswei@google.com> 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="utf-8" Content-Transfer-Encoding: 8bit On Wed, 14 Jan 2026 14:52:41 +0000, Lucas Wei wrote: > When software issues a Cache Maintenance Operation (CMO) targeting a > dirty cache line, the CPU and DSU cluster may optimize the operation by > combining the CopyBack Write and CMO into a single combined CopyBack > Write plus CMO transaction presented to the interconnect (MCN). > For these combined transactions, the MCN splits the operation into two > separate transactions, one Write and one CMO, and then propagates the > write and optionally the CMO to the downstream memory system or external > Point of Serialization (PoS). > However, the MCN may return an early CompCMO response to the DSU cluster > before the corresponding Write and CMO transactions have completed at > the external PoS or downstream memory. As a result, stale data may be > observed by external observers that are directly connected to the > external PoS or downstream memory. > > [...] Applied to arm64 (for-next/errata), thanks! [1/1] arm64: errata: Workaround for SI L1 downstream coherency issue https://git.kernel.org/arm64/c/3fed7e0059f0 Cheers, -- Will https://fixes.arm64.dev https://next.arm64.dev https://will.arm64.dev