Re: [PATCH v6] PCI: mediatek: Fix integer truncation and handle oversized resources

[sashiko-bot@kernel.org]

> resource_size() returns a resource_size_t, which can be 64-bit on
> 64-bit architectures or 32-bit systems with LPAE/PAE enabled.
> Passing this directly to fls(), which accepts an unsigned int,
> implicitly truncates the upper bits.
> 
> Furthermore, AHB2PCIE_SIZE() uses a 5-bit mask GENMASK(4, 0). If
> the size order exceeds the range representable by this field,
> higher bits are discarded by the mask. This can leave the hardware
> translation window smaller than the OS resource, causing bus
> errors when accessing BARs in the unmapped upper region.
> 
> Fix this by using fls64(size) to calculate the size order without
> truncating the resource size, and return -EINVAL if the size order
> exceeds the supported range.
> 
> [ ... ]
>   sizes and prevent integer truncation.
>   [Subject: PCI: mediatek: Fix integer truncation in fls()
>   for resource size]
> 
> Signed-off-by: Sreeraj S Kurup <sreekuttan2156239@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261028113453.2599-1-sreekuttan2156239@gmail.com?part=1