Re: [PATCH v3] PCI: mediatek: Fix integer truncation and handle oversized resources

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] PCI: mediatek: build failure due to invalid port->dev access
--

commit 40759eff660bb6850cba10f5b37e699dc72c75cb
Author: Sreeraj S Kurup <sreekuttan2156239@gmail.com>

PCI: mediatek: Fix integer truncation and handle oversized resources

This commit fixes integer truncation issues when calculating the size order
for AHB to PCIe translation windows by using fls64(). It also adds checks
to return -EINVAL if the resource size exceeds the maximum supported 31-bit
window order.

> diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> index 3a3e91cd0c211..1b0ab5a2c73cc 100644
> --- a/drivers/pci/controller/pcie-mediatek.c
> +++ b/drivers/pci/controller/pcie-mediatek.c
[ ... ]
> @@ -753,8 +756,18 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
>  		mtk_pcie_enable_msi(port);
>  
>  	/* Set AHB to PCIe translation windows */
> +	size = resource_size(mem);
> +	if (!size)
> +		return -EINVAL;
> +
> +	size_order = fls64(size - 1);
> +	if (size_order > 31) {
> +		dev_err(port->dev, "Memory resource size too large: %pa\n", &size);

[Severity: Low]
Does this code compile? Looking at the definition of struct mtk_pcie_port,
it does not appear to have a dev member.

Could this be causing a build failure, and should it use port->pcie->dev
instead?

> +		return -EINVAL;
> +	}
> +
>  	val = lower_32_bits(mem->start) |
> -	      AHB2PCIE_SIZE(fls(resource_size(mem)));
> +	      AHB2PCIE_SIZE(size_order);
>  	writel(val, port->base + PCIE_AHB_TRANS_BASE0_L);
[ ... ]
> @@ -829,8 +844,18 @@ static int mtk_pcie_startup_port_en7528(struct mtk_pcie_port *port)
>  		mtk_pcie_enable_msi(port);
>  
>  	/* Set AHB to PCIe translation windows */
> +	size = resource_size(mem);
> +	if (!size)
> +		return -EINVAL;
> +
> +	size_order = fls64(size - 1);
> +	if (size_order > 31) {
> +		dev_err(port->dev, "Memory resource size too large: %pa\n", &size);

[Severity: Low]
This looks like the same build issue here. Should this use pcie->dev,
since struct mtk_pcie_port lacks a dev member?

> +		return -EINVAL;
> +	}
> +
>  	val = lower_32_bits(mem->start) |
> -	      AHB2PCIE_SIZE(fls(resource_size(mem)));
> +	      AHB2PCIE_SIZE(size_order);
>  	writel(val, port->base + PCIE_AHB_TRANS_BASE0_L);

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260930114218.2655-1-sreekuttan2156239@gmail.com?part=1