From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/7] iommu/arm-smmu: Work around MMU-500 prefetch errata
Date: Thu, 21 Apr 2016 17:16:45 +0100 [thread overview]
Message-ID: <20160421161645.GJ929@arm.com> (raw)
In-Reply-To: <0484444b6257bfb6adb68405a72c64fc4fc98142.1460391217.git.robin.murphy@arm.com>
On Wed, Apr 13, 2016 at 06:12:59PM +0100, Robin Murphy wrote:
> MMU-500 erratum #841119 is tickled by a particular set of circumstances
> interacting with the next-page prefetcher. Since said prefetcher is
> quite dumb and actually detrimental to performance in some cases (by
> causing unwanted TLB evictions for non-sequential access patterns), we
> lose very little by turning it off, and what we gain is a guarantee that
> the erratum is never hit.
>
> As a bonus, the same workaround will also prevent erratum #826419 once
> v7 short descriptor support is implemented.
>
> CC: Catalin Marinas <catalin.marinas@arm•com>
> CC: Will Deacon <will.deacon@arm•com>
> Signed-off-by: Robin Murphy <robin.murphy@arm•com>
> ---
> Documentation/arm64/silicon-errata.txt | 1 +
> drivers/iommu/arm-smmu.c | 16 +++++++++++++++-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt
> index 806f91c..c6938e5 100644
> --- a/Documentation/arm64/silicon-errata.txt
> +++ b/Documentation/arm64/silicon-errata.txt
> @@ -53,6 +53,7 @@ stable kernels.
> | ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 |
> | ARM | Cortex-A57 | #852523 | N/A |
> | ARM | Cortex-A57 | #834220 | ARM64_ERRATUM_834220 |
> +| ARM | MMU-500 | #841119,#826419 | N/A |
Found it :)
Will
next prev parent reply other threads:[~2016-04-21 16:16 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-13 17:12 [PATCH 0/7] arm-smmu: Implementation and context format differentiation Robin Murphy
2016-04-13 17:12 ` [PATCH 1/7] iommu/arm-smmu: Differentiate specific implementations Robin Murphy
2016-04-13 21:15 ` Chalamarla, Tirumalesh
2016-04-13 17:12 ` [PATCH 2/7] iommu/arm-smmu: Convert ThunderX workaround to new method Robin Murphy
2016-04-13 21:16 ` Chalamarla, Tirumalesh
2016-04-13 17:12 ` [PATCH 3/7] iommu/arm-smmu: Work around MMU-500 prefetch errata Robin Murphy
2016-04-21 16:15 ` Will Deacon
2016-04-21 16:16 ` Will Deacon [this message]
2016-04-13 17:13 ` [PATCH 4/7] io-64-nonatomic: Add relaxed accessor variants Robin Murphy
2016-04-21 16:18 ` Will Deacon
2016-04-22 17:08 ` Robin Murphy
2016-04-25 13:32 ` Will Deacon
2016-04-25 15:21 ` Arnd Bergmann
2016-04-25 15:28 ` Robin Murphy
2016-04-25 15:41 ` Arnd Bergmann
2016-04-25 16:11 ` Will Deacon
2016-04-25 16:11 ` Arnd Bergmann
2016-04-26 10:38 ` [PATCH v2] " Robin Murphy
2016-04-13 17:13 ` [PATCH 5/7] iommu/arm-smmu: Tidy up 64-bit/atomic I/O accesses Robin Murphy
2016-04-13 17:13 ` [PATCH 6/7] iommu/arm-smmu: Decouple context format from kernel config Robin Murphy
2016-04-21 16:30 ` Will Deacon
2016-04-22 17:38 ` Robin Murphy
2016-04-25 11:02 ` Will Deacon
2016-04-25 13:14 ` Robin Murphy
2016-04-25 13:41 ` Will Deacon
2016-04-25 16:21 ` Robin Murphy
2016-04-28 16:12 ` [PATCH v2] " Robin Murphy
2016-04-13 17:13 ` [PATCH 7/7] iommu/arm-smmu: Support SMMUv1 64KB supplement Robin Murphy
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