[redhat] New configs in arch/arm64

Hi,

As part of the ongoing rebase effort, the following configuration options need to be reviewed.

As a reminder, the ARK configuration flow involves moving unreviewed configuration options from the pending directory to the ark directory. In the diff below, options are removed from the pending directory and added to the ark hierarchy. The final options that need to be ACKed are the files that are being added to the ark hierarchy.

If the value for a file that is added should be changed, please reply with a better option.

CONFIG_ARM64_ERRATUM_1508412:

This option adds a workaround for Arm Cortex-A77 erratum 1508412.

Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence of a store-exclusive or read of PAR_EL1 and a load with device or non-cacheable memory attributes. The workaround depends on a firmware counterpart.

KVM guests must also have the workaround implemented or they can deadlock the system.

Work around the issue by inserting DMB SY barriers around PAR_EL1 register reads and warning KVM users. The DMB barrier is sufficient to prevent a speculative PAR_EL1 read.

If unsure, say Y.

Symbol: ARM64_ERRATUM_1508412 [=y] Type : bool Defined at arch/arm64/Kconfig:639 Prompt: Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read Location: -> Kernel Features -> ARM errata workarounds via the alternatives framework

---

Cc: Mark Salter msalter@redhat.com Signed-off-by: Fedora Kernel Team kernel-team@fedoraproject.org