I think the answer is "Yes", but I want to get a second opinion.
I need memory that is mapped into user space (so that I can manage it as a BIG heap) but is not cached by the CPU, a PPC405GPr running kernel 2.4.30something. A possible solution is to in my driver support mmap and implement the nopage function. The pages that I create in the nopage will be allocated by the consistent_alloc function, which returns pages marked as NO_CACHE, and so should be uncached. The question is, "Is this NO_CACHE status/flag preserved when it is mapped into the user address space? So far as I can see browsing the do_no_page function in memory.c, that bit is indeed preserved in the mapping. Am I right? Alternatively, is there a way to change a region of memory no unpaged, a la mlock for locking pages? I would rather not keep a table of page pointers for 256Meg of memory just so I can do a consistent_free later:-( -- Steve Williams "The woods are lovely, dark and deep. steve at icarus.com But I have promises to keep, http://www.icarus.com and lines to code before I sleep, http://www.picturel.com And lines to code before I sleep."
