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| author | Catalin Marinas <catalin.marinas@arm.com> | 2019-10-28 16:12:40 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2019-10-28 16:12:40 +0000 |
| commit | 6a036afb5511418995359a9131dbea276758bd10 (patch) | |
| tree | 704faa6c21fd449ed2117f95775828d68d326a89 /Documentation/arm64/silicon-errata.rst | |
| parent | ba95e9bd963784088709050b72363f57c4861deb (diff) | |
| parent | 27a22fbdeedd6c5c451cf5f830d51782bf50c3a2 (diff) | |
| download | lwn-6a036afb5511418995359a9131dbea276758bd10.tar.gz lwn-6a036afb5511418995359a9131dbea276758bd10.zip | |
Merge branch 'for-next/neoverse-n1-stale-instr' into for-next/core
Neoverse-N1 cores with the 'COHERENT_ICACHE' feature may fetch stale
instructions when software depends on prefetch-speculation-protection
instead of explicit synchronization. [0]
The workaround is to trap I-Cache maintenance and issue an
inner-shareable TLBI. The affected cores have a Coherent I-Cache, so the
I-Cache maintenance isn't necessary. The core tells user-space it can
skip it with CTR_EL0.DIC. We also have to trap this register to hide the
bit forcing DIC-aware user-space to perform the maintenance.
To avoid trapping all cache-maintenance, this workaround depends on
a firmware component that only traps I-cache maintenance from EL0 and
performs the workaround.
For user-space, the kernel's work is to trap CTR_EL0 to hide DIC, and
produce a fake IminLine. EL3 traps the now-necessary I-Cache maintenance
and performs the inner-shareable-TLBI that makes everything better.
[0] https://developer.arm.com/docs/sden885747/latest/arm-neoverse-n1-mp050-software-developer-errata-notice
* for-next/neoverse-n1-stale-instr:
arm64: Silence clang warning on mismatched value/register sizes
arm64: compat: Workaround Neoverse-N1 #1542419 for compat user-space
arm64: Fake the IminLine size on systems affected by Neoverse-N1 #1542419
arm64: errata: Hide CTR_EL0.DIC on systems affected by Neoverse-N1 #1542419
Diffstat (limited to 'Documentation/arm64/silicon-errata.rst')
| -rw-r--r-- | Documentation/arm64/silicon-errata.rst | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst index ab7ed2fd072f..f3d2bea25d82 100644 --- a/Documentation/arm64/silicon-errata.rst +++ b/Documentation/arm64/silicon-errata.rst @@ -88,6 +88,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +----------------+-----------------+-----------------+-----------------------------+ |