On Fri, 2007-07-13 at 15:25 +0200, Geert Uytterhoeven wrote: > kmap() just returns page_address() on ppc64, as there's no highmem. > kunmap() is a no-op.
> So technically I could just use page_address() directly, but Christoph > wanted > me to keep the kmap()/kunmap() sequence because it's considered a good > practice. The point isn't what kmap and kunmap do ... it's the addresses they return. By and large, a kernel virtual address for a page is different from the user virtual address. If the cache is virtually indexed you get different cache lines for the same page ... and that sets you up with aliases you need to resolve. parisc is the same ... our kmap/kunmap are nops as well, but our kernel virtual addresses are still different from the user virtual ones. James _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
