[PATCH] PPC: PCI: Fix pcibios_io_space_offset() so it works for 32-bit ptr/64-bit rsrcs

[Bjorn Helgaas]

On Tue, Jun 5, 2012 at 11:15 PM, Benjamin Herrenschmidt
<benh at kernel.crashing.org> wrote:
> On Tue, 2012-06-05 at 23:50 -0400, Ben Collins wrote:
>> The commit introducing pcibios_io_space_offset() was ignoring 32-bit to
>> 64-bit sign extention, which is the case on ppc32 with 64-bit resource
>> addresses. This only seems to have shown up while running under QEMU for
>> e500mc target. It may or may be suboptimal that QEMU has an IO base
>> address > 32-bits for the e500-pci implementation, but 1) it's still a
>> regression and 2) it's more correct to handle things this way.
>
> See Bjorn, we both did end up getting it wrong :-)

Ooh, sorry about that.  Who's going to push this fix?  I don't see it
in Linus' tree yet.  If you want me to, please forward me the original
patch.

>> Signed-off-by: Ben Collins <bcollins at ubuntu.com>
>> Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
>
> Acked-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
>
>>  arch/powerpc/kernel/pci-common.c |    8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
>> index 8e78e93..be9ced7 100644
>> --- a/arch/powerpc/kernel/pci-common.c
>> +++ b/arch/powerpc/kernel/pci-common.c
>> @@ -1477,9 +1477,15 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
>>       return pci_enable_resources(dev, mask);
>>  }
>>
>> +/* Before assuming too much here, take care to realize that we need sign
>> + * extension from 32-bit pointers to 64-bit resource addresses to work.
>> + */
>>  resource_size_t pcibios_io_space_offset(struct pci_controller *hose)
>>  {
>> -     return (unsigned long) hose->io_base_virt - _IO_BASE;
>> +     long vbase = (long)hose->io_base_virt;
>> +     long io_base = _IO_BASE;
>> +
>> +     return (resource_size_t)(vbase - io_base);
>>  }
>>
>>  static void __devinit pcibios_setup_phb_resources(struct pci_controller *hose, struct list_head *resources)
>
>