• Benjamin Herrenschmidt's avatar
    [POWERPC] Fix mmap of PCI resource with hack for X · 396a1a58
    Benjamin Herrenschmidt authored
    The powerpc version of pci_resource_to_user() and associated hooks
    used by /proc/bus/pci and /sys/bus/pci mmap have been broken for some
    time on machines that don't have a 1:1 mapping of devices (basically
    on non-PowerMacs) and have PCI devices above 32 bits.
    
    This attempts to fix it as well as possible.
    
    The rule is supposed to be that pci_resource_to_user() always converts
    the resources back into a BAR values since that's what the /proc
    interface was supposed to deal with. However, for X to work on
    platforms where PCI MMIO is not mapped 1:1, it became a habit of
    platforms like powerpc to pass "fixed up" values there since X expects
    to be able to use values from /proc/bus/pci/devices as offsets to mmap
    of /dev/mem...
    
    So we keep that contraption here, causing also /sys/*/resource to
    expose fully absolute MMIO addresses instead of BAR values, which is
    ugly, but should still work as long as those are only used to calculate
    alignment within a page.
    
    X is still broken when built 32 bits on machines where PCI MMIO can be
    above 32-bit space unfortunately.
    Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    396a1a58
pci-bridge.h 5.04 KB