makes more sense to build the kernel as N32 rather than N64... or possibly N32 with 64-bit paddr_t.
In some reliefing side of "64bit" kernel, post-R4000 needs 32bit PTE to absorb 36/40 paddr space since PFN field in TLBlo is designed shifted toward LSB to make possible sizeof(pte_t) == 4. C.f., 36bit extension in other CPU architectures. Down side of the design was/is X bit brings larger address space _and_ 64bit ld/sd instruction availablity. Toru Nishimura / ALKYL Technology