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authorRobin Murphy <robin.murphy@arm.com>2016-04-13 18:12:59 +0100
committerWill Deacon <will.deacon@arm.com>2016-05-03 18:23:02 +0100
commitf0cfffc48cac516e37711786227f6808491913a5 (patch)
tree889f2264c6e081e8778db9396b5a7c6adc4ebf37 /Documentation/arm64
parente086d912d4d78781652669618e7fb01a4d466703 (diff)
downloadlinux-f0cfffc48cac516e37711786227f6808491913a5.tar.gz
iommu/arm-smmu: Work around MMU-500 prefetch errata
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>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'Documentation/arm64')
-rw-r--r--Documentation/arm64/silicon-errata.txt1
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt
index 806f91cdd45d..c6938e50e71f 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                     |
 |                |                 |                 |                         |
 | Cavium         | ThunderX ITS    | #22375, #24313  | CAVIUM_ERRATUM_22375    |
 | Cavium         | ThunderX GICv3  | #23154          | CAVIUM_ERRATUM_23154    |