From: Jason Gunthorpe <jgg@nvidia.com>
To: Will Deacon <will@kernel.org>
Cc: Shanker Donthineni <sdonthineni@nvidia.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Vladimir Murzin <vladimir.murzin@arm.com>,
linux-arm-kernel@lists.infradead.org,
Mark Rutland <mark.rutland@arm.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
Vikram Sethi <vsethi@nvidia.com>,
Jason Sequeira <jsequeira@nvidia.com>
Subject: Re: [PATCH v3] arm64: errata: Workaround NVIDIA Olympus device store/load ordering erratum
Date: Thu, 11 Jun 2026 14:49:54 -0300 [thread overview]
Message-ID: <20260611174954.GC1962447@nvidia.com> (raw)
In-Reply-To: <aiq5VigmtZq9GlAm@willie-the-truck>
On Thu, Jun 11, 2026 at 02:34:14PM +0100, Will Deacon wrote:
> I still reckon you should do something with the memcpy-to-io routines.
> A simple option could be to make dgh() a dmb on parts with the erratum?
> That at least moves the barrier out of the loop.
AFAIK only callers that know they are using WC memory should be
calling dgh() and in that case we know it is NORMAL-NC and we don't
need a different barrier
Other random users calling memcpy_to_io functions on real IO don't
have to do dgh(), and AFAIK it doesn't do anything on the Device
memory types?
Jason
prev parent reply other threads:[~2026-06-11 17:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-10 16:48 [PATCH v3] arm64: errata: Workaround NVIDIA Olympus device store/load ordering erratum Shanker Donthineni
2026-06-11 13:34 ` Will Deacon
2026-06-11 14:08 ` Shanker Donthineni
2026-06-11 15:08 ` Vladimir Murzin
2026-06-11 16:00 ` Shanker Donthineni
2026-06-11 17:49 ` Jason Gunthorpe [this message]
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