8xx: Update TLB asm so it behaves as linux mm expects.

Update the TLB asm to make proper use of _PAGE_DIRTY and _PAGE_ACCESSED.
Get rid of _PAGE_HWWRITE too.
  - PRESENT is copied to ACCESSED, fixing accounting
  - DIRTY is mapped to 0x100, the changed bit, and is set directly
    when a page has been made dirty.
  - Proper RO/RW mapping of user space.
  - Free up 2 SW TLB bits in the linux pte(add back _PAGE_WRITETHRU ?)
  - kernel RO/user NA support. Not sure this is really needed, would save
    a few insn if not required.
  - A few more instructions in the DTLB Miss routine.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Willy Tarreau <w@1wt.eu>
2 files changed