Hi All
We are trying to implement errata which is applicable for below CPUs: <CPUs> : <Errata No.> Cortex-A53: 1530924 Cortex-A76: 1165522 Cortex-A72: 1319367 Cortex-A57: 1319537 Cortex-A55: 1530923
Errata Description: A speculative Address Translation (AT) instruction translates using registers that are associated with an out-of-context translation regime and caches the resulting translation in the TLB. A subsequent translation request that is generated when the out-of-context translation regime is current uses the previous cached TLB entry producing an incorrect virtual to physical mapping.
Probable solution is to implement below fix in context.S file: During ELx (1 or 2) context save: · Operate TCR_ELx(1/2) to disable page table walk by operating EPD bits o This will avoid any page table walk for S-EL1 or S-EL2. This will help in avoiding caching of translations in TLB for S-EL1/S-EL2 in EL3. · Save all system registers (which is already available) except TCR · Clear EPD bits of TCR and then save. (Just to enable PTW during restore context).
During ELx (1 or 2) context restore:
* Operate TCR_ELx(1/2) to disable page table walk by operating EPD bits * Restore all system registers (which are saved during context save) except TCR register. * Restore TCR_ELx(1/2) register (which enable back PTW). With above we ensured that there will be no page table walk for S-EL1 and S-EL2 in EL3. is this proper other way to fix this problem? Need some suggestion/use cases where and all we need this workaround in TF-A code.
Thanks Manish Badarkhe IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.