CVE-2023-52481

In the Linux kernel, the following vulnerability has been resolved:

arm64: errata: Add Cortex-A520 speculative unprivileged load workaround

Implement the workaround for ARM Cortex-A520 erratum 2966298. On an

affected Cortex-A520 core, a speculatively executed unprivileged load

might leak data from a privileged load via a cache side channel. The

issue only exists for loads within a translation regime with the same

translation (e.g. same ASID and VMID). Therefore, the issue only affects

the return to EL0.

The workaround is to execute a TLBI before returning to EL0 after all

loads of privileged data. A non-shareable TLBI to any address is

sufficient.

The workaround isn't necessary if page table isolation (KPTI) is

enabled, but for simplicity it will be. Page table isolation should

normally be disabled for Cortex-A520 as it supports the CSV3 feature

and the E0PD feature (used when KASLR is enabled).