Map kernel stacks only at unique addresses.
Use one TSS per process.
Add sysarch calls for modifying IOPL and the I/O permission bitmap.
Add a compacting GDT entry allocator, for TSS and LDT selectors.
Enable modifying %fs and %gs with PT_SETREGS.
Sanitize various bits of code.
* Inline some functions.
* Eliminate redundant calls to pmap_page_index().
* Reduce the number of TLB flushes in accordance with the i386 SSWG.
* Inline pmap_remove() in pmap_remove_all(). (Most if it is unnecessary.)
* Allocate pv_entry's in pages, and keep a list of free entries in each page,
and a list of pages with free entries. (Trying to reduce malloc() overhead,
and improve locality of reference.)
* Remove a couple of macros that aren't really useful.
* Remove pmap_kernel() completely.
christos