what will be caused by setting TLB's virtual address part to unmapped address?

["Bin Chen" <binary.chen@xxxxxxxxx>]

Hi,

In MIPS64, the 0xFFFFFFFF80000000 is a kernel unmapped area, what will
be caused by setting up a TLB entry with the virtual address be
0xFFFFFFFF80000000?

I ask this question because I noticed u-boot's TLB init code use the
address from 0xFFFFFFFF80000000 to fill in the blank tlb, but I don't
know the purpose of this operation.

Thanks in advance.

B.C