On Mon, 1 Feb 2010, Ralf Baechle wrote: > Write a value with all bits set to c0_entryhi, then read it back again. > The set bits in the VPN2 bitfield will indicate the size of the virtual > address range supported. The MIPS64 documentation also calls this value > SEGBITS. The nice thing about this probe is that it is supported for > all 64-bit MIPS processors except the R8000 which has an entirely different > TLB scheme anyway. > > Similarly it is possible to probe the physical address range in either > c0_entrylo0 or c0_entrylo1. This is also of interest on 32-bit processors. Indeed -- IIRC the architecture spec calls this value PABITS. I wasn't sure about the legacy processors -- if that works with them too, then it's even better. Maciej
