| Will Deacon | 9cb9c9e | 2015-11-17 14:45:47 +0000 | [diff] [blame] | 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 | |
| Ding Tianhong | 6e01398 | 2017-02-09 17:00:34 +0000 | [diff] [blame] | 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 | MMU-500 | #841119,#826419 | N/A | |
| 58 | | | | | | |
| 59 | | Cavium | ThunderX ITS | #22375, #24313 | CAVIUM_ERRATUM_22375 | |
| 60 | | Cavium | ThunderX ITS | #23144 | CAVIUM_ERRATUM_23144 | |
| 61 | | Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 | |
| 62 | | Cavium | ThunderX Core | #27456 | CAVIUM_ERRATUM_27456 | |
| 63 | | Cavium | ThunderX SMMUv2 | #27704 | N/A | |
| 64 | | | | | | |
| 65 | | Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 | |
| 66 | | | | | | |
| 67 | | Hisilicon | Hip0{5,6,7} | #161010101 | HISILICON_ERRATUM_161010101 | |
| 68 | | | | | | |
| Christopher Covington | 38fd94b | 2017-02-08 15:08:37 -0500 | [diff] [blame] | 69 | | Qualcomm Tech. | Falkor v1 | E1003 | QCOM_FALKOR_ERRATUM_1003 | |
| Ding Tianhong | 6e01398 | 2017-02-09 17:00:34 +0000 | [diff] [blame] | 70 | | Qualcomm Tech. | Falkor v1 | E1009 | QCOM_FALKOR_ERRATUM_1009 | |
| Shanker Donthineni | 90922a2 | 2017-03-07 08:20:38 -0600 | [diff] [blame] | 71 | | Qualcomm Tech. | QDF2400 ITS | E0065 | QCOM_QDF2400_ERRATUM_0065 | |