From: Will Deacon <will@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
Jonathan Corbet <corbet@lwn.net>, Lucas Wei <lucaswei@google.com>
Cc: kernel-team@android.com, Will Deacon <will@kernel.org>,
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 [thread overview]
Message-ID: <176917501918.797415.179034767474498162.b4-ty@kernel.org> (raw)
In-Reply-To: <20260114145243.3458315-1-lucaswei@google.com>
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
prev parent reply other threads:[~2026-01-23 17:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-14 14:52 Lucas Wei
2026-01-14 18:25 ` Randy Dunlap
2026-01-15 2:11 ` Lucas Wei
2026-01-15 6:26 ` Randy Dunlap
2026-01-23 17:49 ` Will Deacon [this message]
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