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[muen/linux.git] / Documentation / arm64 / silicon-errata.txt
1                 Silicon Errata and Software Workarounds
2                 =======================================
3
4 Author: Will Deacon <will.deacon@arm.com>
5 Date  : 27 November 2015
6
7 It is an unfortunate fact of life that hardware is often produced with
8 so-called "errata", which can cause it to deviate from the architecture
9 under specific circumstances.  For hardware produced by ARM, these
10 errata are broadly classified into the following categories:
11
12   Category A: A critical error without a viable workaround.
13   Category B: A significant or critical error with an acceptable
14               workaround.
15   Category C: A minor error that is not expected to occur under normal
16               operation.
17
18 For more information, consult one of the "Software Developers Errata
19 Notice" documents available on infocenter.arm.com (registration
20 required).
21
22 As far as Linux is concerned, Category B errata may require some special
23 treatment in the operating system. For example, avoiding a particular
24 sequence of code, or configuring the processor in a particular way. A
25 less common situation may require similar actions in order to declassify
26 a Category A erratum into a Category C erratum. These are collectively
27 known as "software workarounds" and are only required in the minority of
28 cases (e.g. those cases that both require a non-secure workaround *and*
29 can be triggered by Linux).
30
31 For software workarounds that may adversely impact systems unaffected by
32 the erratum in question, a Kconfig entry is added under "Kernel
33 Features" -> "ARM errata workarounds via the alternatives framework".
34 These are enabled by default and patched in at runtime when an affected
35 CPU is detected. For less-intrusive workarounds, a Kconfig option is not
36 available and the code is structured (preferably with a comment) in such
37 a way that the erratum will not be hit.
38
39 This approach can make it slightly onerous to determine exactly which
40 errata are worked around in an arbitrary kernel source tree, so this
41 file acts as a registry of software workarounds in the Linux Kernel and
42 will be updated when new workarounds are committed and backported to
43 stable kernels.
44
45 | Implementor    | Component       | Erratum ID      | Kconfig                     |
46 +----------------+-----------------+-----------------+-----------------------------+
47 | ARM            | Cortex-A53      | #826319         | ARM64_ERRATUM_826319        |
48 | ARM            | Cortex-A53      | #827319         | ARM64_ERRATUM_827319        |
49 | ARM            | Cortex-A53      | #824069         | ARM64_ERRATUM_824069        |
50 | ARM            | Cortex-A53      | #819472         | ARM64_ERRATUM_819472        |
51 | ARM            | Cortex-A53      | #845719         | ARM64_ERRATUM_845719        |
52 | ARM            | Cortex-A53      | #843419         | ARM64_ERRATUM_843419        |
53 | ARM            | Cortex-A57      | #832075         | ARM64_ERRATUM_832075        |
54 | ARM            | Cortex-A57      | #852523         | N/A                         |
55 | ARM            | Cortex-A57      | #834220         | ARM64_ERRATUM_834220        |
56 | ARM            | Cortex-A72      | #853709         | N/A                         |
57 | ARM            | Cortex-A73      | #858921         | ARM64_ERRATUM_858921        |
58 | ARM            | MMU-500         | #841119,#826419 | N/A                         |
59 |                |                 |                 |                             |
60 | Cavium         | ThunderX ITS    | #22375, #24313  | CAVIUM_ERRATUM_22375        |
61 | Cavium         | ThunderX ITS    | #23144          | CAVIUM_ERRATUM_23144        |
62 | Cavium         | ThunderX GICv3  | #23154          | CAVIUM_ERRATUM_23154        |
63 | Cavium         | ThunderX Core   | #27456          | CAVIUM_ERRATUM_27456        |
64 | Cavium         | ThunderX Core   | #30115          | CAVIUM_ERRATUM_30115        |
65 | Cavium         | ThunderX SMMUv2 | #27704          | N/A                         |
66 | Cavium         | ThunderX2 SMMUv3| #74             | N/A                         |
67 | Cavium         | ThunderX2 SMMUv3| #126            | N/A                         |
68 |                |                 |                 |                             |
69 | Freescale/NXP  | LS2080A/LS1043A | A-008585        | FSL_ERRATUM_A008585         |
70 |                |                 |                 |                             |
71 | Hisilicon      | Hip0{5,6,7}     | #161010101      | HISILICON_ERRATUM_161010101 |
72 | Hisilicon      | Hip0{6,7}       | #161010701      | N/A                         |
73 |                |                 |                 |                             |
74 | Qualcomm Tech. | Falkor v1       | E1003           | QCOM_FALKOR_ERRATUM_1003    |
75 | Qualcomm Tech. | Falkor v1       | E1009           | QCOM_FALKOR_ERRATUM_1009    |
76 | Qualcomm Tech. | QDF2400 ITS     | E0065           | QCOM_QDF2400_ERRATUM_0065   |