Greetings,
I would like to enable top-byte ignore support on the FVP. I would be grateful on any guidelines on how to do that. Thank you very much!
Best regards,
Mohannad Ismail
Hi Mohannad, top-byte ignore (TBI) is controlled by the TBI bit (bit 20) in the TCR_EL3 register. You can set this either in the code running on the model, or by writing to the register via a debugger attached to the model.
there are TCR registers for each EL. i.e., TCR_EL2 and TCR_EL1 . you would need to set all three for TBI to be active across all levels.
Thank you for your reply
Is this done by modifying the arm-tf firmware or by modifying the boot loader? How do I write to the register? Do you mean that I can set all three levels from the userspace? Is that done using prctl? Or do I pass some parameter to the FVP in a similar manner to enabling pointer authentication?