On Wed, Jun 18, 2025 at 01:56:17PM +0000, Wannes Bouwen (Nokia) wrote:
> [v3 PATCH 1/1] PCI: of: fix non-prefetchable region address range check.
>
> According to the PCIe spec (PCIe r6.3, sec 7.5.1.3.8), non-prefetchable
> memory supports only 32-bit host bridge windows (both base address as
> limit address).
>
> In the kernel there is a check that prints a warning if a
> non-prefetchable resource's size exceeds the 32-bit limit.
>
> The check currently checks the size of the resource, while actually the
> check should be done on the PCIe end address of the non-prefetchable
> window.
>
> Move the check to devm_of_pci_get_host_bridge_resources() where the PCIe
> addresses are available and use the end address instead of the size of
> the window.
>
> Fixes: fede8526cc48 (PCI: of: Warn if non-prefetchable memory aperture
> size is > 32-bit)
> Signed-off-by: Wannes Bouwen <wannes.bouwen@xxxxxxxxx>
> ---
>
> v3:
> - Update subject and description + add changelog
>
> v2:
> - Use PCI address range instead of window size to check that window is
> within a 32bit boundary.
>
> ---
> drivers/pci/of.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> index 3579265f1198..4fffa32c7c3d 100644
> --- a/drivers/pci/of.c
> +++ b/drivers/pci/of.c
> @@ -400,6 +400,10 @@ static int devm_of_pci_get_host_bridge_resources(struct device *dev,
> *io_base = range.cpu_addr;
> } else if (resource_type(res) == IORESOURCE_MEM) {
> res->flags &= ~IORESOURCE_MEM_64;
> +
> + if (!(res->flags & IORESOURCE_PREFETCH))
> + if (upper_32_bits(range.pci_addr + range.size - 1))
> + dev_warn(dev, "Memory resource size exceeds max for 32 bits\n");
Seems mostly right to me. I think we should update the message to
talk about the *address* instead of the size, since that's the real
problem. Also would be nice to include the resource (%pR) and the
corresponding bus addresses as we do in pci_register_host_bridge().
> }
>
> pci_add_resource_offset(resources, res, res->start - range.pci_addr);
> @@ -622,10 +626,6 @@ static int pci_parse_request_of_pci_ranges(struct device *dev,
> case IORESOURCE_MEM:
> res_valid |= !(res->flags & IORESOURCE_PREFETCH);
>
> - if (!(res->flags & IORESOURCE_PREFETCH))
> - if (upper_32_bits(resource_size(res)))
> - dev_warn(dev, "Memory resource size exceeds max for 32 bits\n");
> -
> break;
> }
> }
> --
> 2.43.5
>
