Silicon Errata and Software Workarounds

Author: Will Deacon <will.deacon@arm.com>

Date : 27 November 2015

It is an unfortunate fact of life that hardware is often produced with so-called “errata”, which can cause it to deviate from the architecture under specific circumstances. For hardware produced by ARM, these errata are broadly classified into the following categories:

Category A

A critical error without a viable workaround.

Category B

A significant or critical error with an acceptable workaround.

Category C

A minor error that is not expected to occur under normal operation.

For more information, consult one of the “Software Developers Errata Notice” documents available on infocenter.arm.com (registration required).

As far as Linux is concerned, Category B errata may require some special treatment in the operating system. For example, avoiding a particular sequence of code, or configuring the processor in a particular way. A less common situation may require similar actions in order to declassify a Category A erratum into a Category C erratum. These are collectively known as “software workarounds” and are only required in the minority of cases (e.g. those cases that both require a non-secure workaround and can be triggered by Linux).

For software workarounds that may adversely impact systems unaffected by the erratum in question, a Kconfig entry is added under “Kernel Features” -> “ARM errata workarounds via the alternatives framework”. These are enabled by default and patched in at runtime when an affected CPU is detected. For less-intrusive workarounds, a Kconfig option is not available and the code is structured (preferably with a comment) in such a way that the erratum will not be hit.

This approach can make it slightly onerous to determine exactly which errata are worked around in an arbitrary kernel source tree, so this file acts as a registry of software workarounds in the Linux Kernel and will be updated when new workarounds are committed and backported to stable kernels.

Implementor

Component

Erratum ID

Kconfig

Allwinner

A64/R18

UNKNOWN1

SUN50I_ERRATUM_UNKNOWN1

ARM

Cortex-A53

#826319

ARM64_ERRATUM_826319

ARM

Cortex-A53

#827319

ARM64_ERRATUM_827319

ARM

Cortex-A53

#824069

ARM64_ERRATUM_824069

ARM

Cortex-A53

#819472

ARM64_ERRATUM_819472

ARM

Cortex-A53

#845719

ARM64_ERRATUM_845719

ARM

Cortex-A53

#843419

ARM64_ERRATUM_843419

ARM

Cortex-A55

#1024718

ARM64_ERRATUM_1024718

ARM

Cortex-A55

#1530923

ARM64_ERRATUM_1530923

ARM

Cortex-A57

#832075

ARM64_ERRATUM_832075

ARM

Cortex-A57

#852523

N/A

ARM

Cortex-A57

#834220

ARM64_ERRATUM_834220

ARM

Cortex-A57

#1319537

ARM64_ERRATUM_1319367

ARM

Cortex-A72

#853709

N/A

ARM

Cortex-A72

#1319367

ARM64_ERRATUM_1319367

ARM

Cortex-A73

#858921

ARM64_ERRATUM_858921

ARM

Cortex-A76

#1188873,1418040

ARM64_ERRATUM_1418040

ARM

Cortex-A76

#1165522

ARM64_ERRATUM_1165522

ARM

Cortex-A76

#1286807

ARM64_ERRATUM_1286807

ARM

Cortex-A76

#1463225

ARM64_ERRATUM_1463225

ARM

Cortex-A77

#1508412

ARM64_ERRATUM_1508412

ARM

Neoverse-N1

#1188873,1418040

ARM64_ERRATUM_1418040

ARM

Neoverse-N1

#1349291

N/A

ARM

Neoverse-N1

#1542419

ARM64_ERRATUM_1542419

ARM

MMU-500

#841119,826419

N/A

Broadcom

Brahma-B53

N/A

ARM64_ERRATUM_845719

Broadcom

Brahma-B53

N/A

ARM64_ERRATUM_843419

Cavium

ThunderX ITS

#22375,24313

CAVIUM_ERRATUM_22375

Cavium

ThunderX ITS

#23144

CAVIUM_ERRATUM_23144

Cavium

ThunderX GICv3

#23154

CAVIUM_ERRATUM_23154

Cavium

ThunderX GICv3

#38539

N/A

Cavium

ThunderX Core

#27456

CAVIUM_ERRATUM_27456

Cavium

ThunderX Core

#30115

CAVIUM_ERRATUM_30115

Cavium

ThunderX SMMUv2

#27704

N/A

Cavium

ThunderX2 SMMUv3

#74

N/A

Cavium

ThunderX2 SMMUv3

#126

N/A

Cavium

ThunderX2 Core

#219

CAVIUM_TX2_ERRATUM_219

Marvell

ARM-MMU-500

#582743

N/A

Freescale/NXP

LS2080A/LS1043A

A-008585

FSL_ERRATUM_A008585

Hisilicon

Hip0{5,6,7}

#161010101

HISILICON_ERRATUM_161010101

Hisilicon

Hip0{6,7}

#161010701

N/A

Hisilicon

Hip0{6,7}

#161010803

N/A

Hisilicon

Hip07

#161600802

HISILICON_ERRATUM_161600802

Hisilicon

Hip08 SMMU PMCG

#162001800

N/A

Qualcomm Tech.

Kryo/Falkor v1

E1003

QCOM_FALKOR_ERRATUM_1003

Qualcomm Tech.

Kryo/Falkor v1

E1009

QCOM_FALKOR_ERRATUM_1009

Qualcomm Tech.

QDF2400 ITS

E0065

QCOM_QDF2400_ERRATUM_0065

Qualcomm Tech.

Falkor v{1,2}

E1041

QCOM_FALKOR_ERRATUM_1041

Qualcomm Tech.

Kryo4xx Gold

N/A

ARM64_ERRATUM_1463225

Qualcomm Tech.

Kryo4xx Gold

N/A

ARM64_ERRATUM_1418040

Qualcomm Tech.

Kryo4xx Silver

N/A

ARM64_ERRATUM_1530923

Qualcomm Tech.

Kryo4xx Silver

N/A

ARM64_ERRATUM_1024718

Fujitsu

A64FX

E#010001

FUJITSU_ERRATUM_010001