Igor Kovalenko wrote:
Another point for implementing claim/release is the need to correctly work with PCI VGA frame buffer.
This shows up when I try to execute linux kernel in sparc64-softmmu. After kernel starts mapping pages using tlb the early low memory mappings set up by openbios code are started to go out from tlb entries. In short time after several lines are printed using prom console the openbios console driver fails because frame buffer pointer is not mapped anymore.
PPC arch seems to have it implemented using claim and map which use memory management in ofmem.c (at least two versions are there). Should the memory management (ofmem.c) be shared by all arches?
I'd imagine that perhaps the claim/release functions could be shared, whereas the map/unmap functions would naturally have to be specific to each architecture. My C is reasonably good, although I don't know too much about SPARC64 (yet!) nor the C side of OpenBIOS. If yourself/Blue Swirl could come up with some code as a starting point, that would be really great :)
ATB,
Mark.