CONFIG_ARM_ERRATA_852421 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
ARM errata: A17: DMB ST might fail to create order between stores
configname: CONFIG_ARM_ERRATA_852421
Linux Kernel Configuration
└─>System Type
└─>ARM errata: A17: DMB ST might fail to create order between stores
In linux kernel since version 4.1 (release Date: 2015-06-21)
This option enables the workaround for the 852421 Cortex-A17
(r1p0, r1p1, r1p2) erratum. Under very rare timing conditions,
execution of a DMB ST instruction might fail to properly order
stores from GroupA and stores from GroupB.
(r1p0, r1p1, r1p2) erratum. Under very rare timing conditions,
execution of a DMB ST instruction might fail to properly order
stores from GroupA and stores from GroupB.