Re: [PATCH v3 1/2] PCI: dwc: Fix a 64bit bug in dw_pcie_ep_raise_msix_irq()

[Niklas Cassel]

On Mon, Jan 22, 2024 at 06:19:52PM +0300, Dan Carpenter wrote:
> The "msg_addr" variable is u64.  However, the "aligned_offset" is an
> unsigned int.  This means that when the code does:
> 
>         msg_addr &= ~aligned_offset;
> 
> it will unintentionally zero out the high 32 bits.  Use ALIGN_DOWN()
> to do the alignment instead.
> 
> Fixes: 2217fffcd63f ("PCI: dwc: endpoint: Fix dw_pcie_ep_raise_msix_irq() alignment support")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> v2: fix typo in commit message
> v3: Use ALIGN_DOWN() instead of ANDing with ~aligned_offset (this is a
>     style improvement).
> 
>  drivers/pci/controller/dwc/pcie-designware-ep.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 5befed2dc02b..51679c6702cf 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -551,7 +551,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>  	}
>  
>  	aligned_offset = msg_addr & (epc->mem->window.page_size - 1);
> -	msg_addr &= ~aligned_offset;
> +	msg_addr = ALIGN_DOWN(msg_addr, epc->mem->window.page_size);
>  	ret = dw_pcie_ep_map_addr(epc, func_no, 0, ep->msi_mem_phys, msg_addr,
>  				  epc->mem->window.page_size);
>  	if (ret)
> -- 
> 2.43.0
> 

Oh.. I just got emails that the patch that this fixes has been backported,
so perhaps we should add:
Cc: stable@xxxxxxxxxxxxxxx
as well...?


Kind regards,
Niklas