On Thu, May 27, 2010 at 03:41:44PM +0200, Geert Uytterhoeven wrote: > On Thu, May 27, 2010 at 15:30, Chris Metcalf <cmetcalf@xxxxxxxxxx> wrote: > > On 5/27/2010 4:41 AM, Arnd Bergmann wrote: > >> On Thursday 27 May 2010, Chris Metcalf wrote: > >>>> +EXPORT_SYMBOL(inb); > >>>> > >>>> If you just remove these definitions, you get a link error for any > >>>> driver that tries to use these, which is probably more helpful than > >>>> the panic. > >>>> > >>>> OTOH, are you sure that you can't just map the PIO calls to mmio functions > >>>> like readb plus some fixed offset? On most non-x86 architectures, the PIO > >>>> area of the PCI bus is just mapped to a memory range somewhere. > >>>> > >>>> > >>> I'll try to remove them and see if anything falls over. ??We don't have > >>> any memory-mapped addresses in the 32-bit architecture, though that > >>> changes with the 64-bit architecture, which introduces IO mappings. ??For > >>> PCI we actually have to do a hypervisor transaction for reads or writes. > >>> > >> Ok, then I assume that PIO would also be a hypervisor call, right? > >> If you don't have MMIO on 32 bit, you might want to not define either > >> PIO (inb, ...) no MMIO (readb, ...) calls there and disable > >> CONFIG_HAVE_MMIO in Kconfig. > >> > > > > We don't define CONFIG_HAVE_MMIO, but drivers certainly seem to use > > ioread/iowrite methods as well as inb/outb without guarding them with > > any particular tests, so we have to provide definitions of some kind for > > all of them. ??I'll confer with our PCI developer to see if we can clean > > up the set of definitions in io.h. > > It's CONFIG_NO_IOMEM (cfr. s390 and um), which is inverted and turned into > CONFIG_HAS_IOMEM, to be checked by drivers. > Likewise for CONFIG_NO_IOPORT for disabling PIO, although you'll probably want to conditionalize this on PCI I/O. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html