This will allow improvements to the pmaps so that they can more easily defer expensive operations, eg tlb/cache flush, til the last possible moment.
Currently this is a no-op on most platforms, so they should see no difference.
Reviewed by Jason.
Thorpe as an extension to the bus_space(9) API.
Only the mainbus has a working mmap... iomd, podulebus and isa dont have
one yet. Its trivial to add the iomd and isa's memory part but am a bit
hessistant to add it without knowing its implications by heart.
Podulebus might be implemented in 32 bits EASI but otherwise its not really
transparent since there is AFAIK no function to explicitly read one byte or
so .. or is this implemented in a higher level ?
ARM26 and arch/arm32/dnard (Shark) kernels compile and RiscPC and Shark
kernels are tested and function OK.
Implications of other ARM systems like hpcarm and ebarm are propably
minimal or solved trivially.
- pmap_enter()
- pmap_remove()
- pmap_protect()
- pmap_kenter_pa()
- pmap_kremove()
as described in pmap(9).
These calls are relatively conservative. It may be possible to
optimize these a little more.
always points to the undefined instruction in question. It's up to the
handler to advance it to the next instruction if it wants execution to
continue there. This is how things have always worked on arm26.
support, which corresponds to one for each CPU_* option, or one for each
cpufunc structure.
Also remove some more residual code for the support of multiple and non-ARM
CPUs.
chris