After modifying mode transition for branch prediction tz_vmm wasn't
working anymore on hw_imx53_tz but the modifications had nothing to do
with the VM code. However, the amount of instructions in the MT before the
VM exception-vector changed. So I tried stuffing the last working version with
NOPs and found that tz_vmm worked for some NOP amounts and for others not.
Thus, I increased the alignment of the VM exception-vector from 16 bytes to 32
bytes, é voila, its working with any amount of NOPs as well as with branch
prediction commits.
ref #474
Previously, we did the protection-domain switches without a transitional
translation table that contains only global mappings. This was fine as long
as the CPU did no speculative memory accesses. However, to enabling branch
prediction triggers such accesses. Thus, if we don't want to invalidate
predictors on every context switch, we need to switch more carefully.
ref #474