1# SPDX-License-Identifier: GPL-2.0-only 2menuconfig RAS 3 bool "Reliability, Availability and Serviceability (RAS) features" 4 help 5 Reliability, availability and serviceability (RAS) is a computer 6 hardware engineering term. Computers designed with higher levels 7 of RAS have a multitude of features that protect data integrity 8 and help them stay available for long periods of time without 9 failure. 10 11 Reliability can be defined as the probability that the system will 12 produce correct outputs up to some given time. Reliability is 13 enhanced by features that help to avoid, detect and repair hardware 14 faults. 15 16 Availability is the probability a system is operational at a given 17 time, i.e. the amount of time a device is actually operating as the 18 percentage of total time it should be operating. 19 20 Serviceability or maintainability is the simplicity and speed with 21 which a system can be repaired or maintained; if the time to repair 22 a failed system increases, then availability will decrease. 23 24 Note that Reliability and Availability are distinct concepts: 25 Reliability is a measure of the ability of a system to function 26 correctly, including avoiding data corruption, whereas Availability 27 measures how often it is available for use, even though it may not 28 be functioning correctly. For example, a server may run forever and 29 so have ideal availability, but may be unreliable, with frequent 30 data corruption. 31 32if RAS 33 34config RAS_CEC 35 bool "Correctable Errors Collector" 36 depends on X86_MCE && MEMORY_FAILURE && DEBUG_FS 37 help 38 This is a small cache which collects correctable memory errors per 4K 39 page PFN and counts their repeated occurrence. Once the counter for a 40 PFN overflows, we try to soft-offline that page as we take it to mean 41 that it has reached a relatively high error count and would probably 42 be best if we don't use it anymore. 43 44 Bear in mind that this is absolutely useless if your platform doesn't 45 have ECC DIMMs and doesn't have DRAM ECC checking enabled in the BIOS. 46 47config RAS_CEC_DEBUG 48 bool "CEC debugging machinery" 49 default n 50 depends on RAS_CEC 51 help 52 Add extra files to (debugfs)/ras/cec to test the correctable error 53 collector feature. "pfn" is a writable file that allows user to 54 simulate an error in a particular page frame. "array" is a read-only 55 file that dumps out the current state of all pages logged so far. 56 57source "drivers/ras/amd/atl/Kconfig" 58 59config RAS_FMPM 60 tristate "FRU Memory Poison Manager" 61 default m 62 depends on AMD_ATL && ACPI_APEI 63 help 64 Support saving and restoring memory error information across reboot 65 using ACPI ERST as persistent storage. Error information is saved with 66 the UEFI CPER "FRU Memory Poison" section format. 67 68 Memory will be retired during boot time and run time depending on 69 platform-specific policies. 70 71endif 72