HEADS UP: MIPS switching to common pmap (uvm/pmap)

[Matt Thomas <matt%3am-software.com@localhost>]

I now have MIPS using the same pmap code as PowerPC BookE in sys/uvm/pmap.  

I plan on merging it into the tree next week.  I’ve tested it on ERLITE, MALTA, and TWRP1025 but I’m sure there are going to some issues.

If you have a MIPS system and you’d like to try a new kernel, let me know and I can built you one.

For those using 64-bit CPUs, using N32 for the kernel will give a decided performance boost.  N32 kernels run with a full 64-bit address.  bus_space, the cache routines, and the page zero and copy routines have been updated to take and use 64-bit direct mapped addresses whenever possible.  This means the N32 kernels can use more memory than fits in KSEG0.  

For MIPS3+ and MIPSNN, the default page size has been changed to 8KB which speeds the kernel.  The locore routines for mips3 have been updated to use mipsNNr2 instructions to increase speed.

By using the common pmap code, MIPS kernel now support dynamically increasing kernel address space.