Re: pci: Arch hook to determine config space size

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To: brking@us.ibm.com
Date:	Mon, 31 Jan 2005 22:56:44 +0100

On Maandag 31 Januar 2005 22:35, Brian King wrote:
> Matthew Wilcox wrote:
> > Basically, ppc64's config ops are broken and need to check the offset
> > being read.  Here's i386:
> >
> > static int pci_conf1_write (int seg, int bus, int devfn, int reg, int len, u32 v
> > alue)
> > {
> >         unsigned long flags;
> >
> >         if ((bus > 255) || (devfn > 255) || (reg > 255))
> >                 return -EINVAL;
>
> Here is a pure ppc64 implementation that does this.

Actually, it doesn't:

> +static int config_access_valid(struct device_node *dn, int where)
> +{
> +       struct device_node *hose_dn = dn->phb->arch_data;
> +
> +       if (where < 256 || hose_dn->pci_ext_config_space)
> +               return 1;

This needs a check for (where < 4096) in case of PCIe or PCI-X.

> @@ -62,6 +72,8 @@ static int rtas_read_config(struct devic
>                 return PCIBIOS_DEVICE_NOT_FOUND;
>         if (where & (size - 1))
>                 return PCIBIOS_BAD_REGISTER_NUMBER;
> +       if (!config_access_valid(dn, where))
> +               return PCIBIOS_BAD_REGISTER_NUMBER;
>  
>         addr = (dn->busno << 16) | (dn->devfn << 8) | where;

addr is still wrong, see my previous mail.

> @@ -110,6 +122,8 @@ static int rtas_write_config(struct devi
>                 return PCIBIOS_DEVICE_NOT_FOUND;
>         if (where & (size - 1))
>                 return PCIBIOS_BAD_REGISTER_NUMBER;
> +       if (!config_access_valid(dn, where))
> +               return PCIBIOS_BAD_REGISTER_NUMBER;
>  
>         addr = (dn->busno << 16) | (dn->devfn << 8) | where;

same here

> @@ -285,6 +309,7 @@ static int __devinit setup_phb(struct de
>         phb->arch_data = dev;
>         phb->ops = &rtas_pci_ops;
>         phb->buid = get_phb_buid(dev);
> +       get_phb_config_space_type(dev);
>  
>         return 0;
>  }

Isn't the config space size a property of the PCI device instead of the
host bridge? For a PCI device behind a PCIe host bridge, this could
still lead to an incorrect config space accesses.

        Arnd <><

PS: I got a permanent fatal error from <linux-pci@vger.kernel.org>, does
that list actually exist?

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