Re: pci: Arch hook to determine config space size

[Brian King <brking@us.ibm.com>]

Grant Grundler wrote:
> On Mon, Jan 31, 2005 at 01:40:04PM -0600, Brian King wrote:
> 
>>CC'ing the linux-pci mailing list...
> 
> 
> thanks...
> 
> 
>>>This patch adds an arch hook so
>>>that individual archs can indicate if the underlying system supports
>>>expanded config space accesses or not.
> 
> 
>>>@@ -653,6 +653,8 @@ static int pci_cfg_space_size(struct pci
>>>			goto fail;
>>>	}
>>>
>>>+	if (!pcibios_exp_cfg_space(dev))
>>>+		goto fail;
>>>	if (pci_read_config_dword(dev, 256, &status) != PCIBIOS_SUCCESSFUL)
>>>		goto fail;
> 
> 
> pci_read_config_dword lands in arch specific code.
> See drivers/pci/access.c:PCI_OP_READ() macro.
> 
> I'm missing what pcibios_exp_cfg_space() does that can't be handled by
> the bus_ops supplied by pci_scan_bus().
> 
> I would expect the pci_read_config_dword to fail for being out of bounds.
> Is that wrong?
> Or is bus_ops not feasible in this case because pcibios needs access
> to pci_dev?

The current patch for this has become essentially that. It is now a 
PPC64 specific patch that adds bounds checking in the PPC64 PCI config 
access functions.

-Brian


-- 
Brian King
eServer Storage I/O
IBM Linux Technology Center