From: Jason Gunthorpe <jgg@nvidia.com>
To: Shanker Donthineni <sdonthineni@nvidia.com>
Cc: Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-arm-kernel@lists.infradead.org,
Vladimir Murzin <vladimir.murzin@arm.com>,
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 v2] arm64: errata: Workaround NVIDIA Olympus device store/load ordering erratum
Date: Wed, 10 Jun 2026 13:11:44 -0300 [thread overview]
Message-ID: <20260610161144.GU1962447@nvidia.com> (raw)
In-Reply-To: <223c49ee-528c-4750-9885-fd8e0247151e@nvidia.com>
On Wed, Jun 10, 2026 at 08:20:28AM -0500, Shanker Donthineni wrote:
> Based on the existing code comments and after reviewing this path again,
> __const_memcpy_toio_aligned32() and __const_memcpy_toio_aligned64()
> appear to be intended for WC regions. Since the erratum is scoped to
> Device-nGnR* accesses, and WC mappings are Normal-NC on arm64, I don’t
> think the STLR workaround should apply to these helpers by default.
Hmm, unfortunately I think the APIs mix together IO and WC both as
__iomem things. However I recall when I was looking a this everyone
was using it for WC.
Jason
prev parent reply other threads:[~2026-06-10 16:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-05 14:45 [PATCH v2] arm64: errata: Workaround NVIDIA Olympus device store/load ordering erratum Shanker Donthineni
2026-06-10 11:28 ` Will Deacon
2026-06-10 12:50 ` Jason Gunthorpe
2026-06-10 12:53 ` Shanker Donthineni
2026-06-10 13:20 ` Shanker Donthineni
2026-06-10 16:11 ` Jason Gunthorpe [this message]
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