runtime_exceptions: Update AT speculative workaround
As per latest mailing communication , we decided to
update AT speculative workaround implementation in order to
disable page table walk for lower ELs(EL1 or EL0) immediately
after context switching to EL3 from lower ELs.
Previous implementation of AT speculative workaround is available
AT speculative workaround is updated as below:
1. Avoid saving and restoring of SCTLR and TCR registers for EL1
in context save and restore routine respectively.
2. On EL3 entry, save SCTLR and TCR registers for EL1.
3. On EL3 entry, update EL1 system registers to disable stage 1
page table walk for lower ELs (EL1 and EL0) and enable EL1
4. On EL3 exit, restore SCTLR and TCR registers for EL1 which
are saved in step 2.
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
3 files changed