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Date:   Mon, 19 Sep 2022 12:29:16 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Vidya Sagar <vidyas@nvidia.com>
Cc:     jingoohan1@gmail.com, gustavo.pimentel@synopsys.com,
        lpieralisi@kernel.org, robh@kernel.org, kw@linux.com,
        bhelgaas@google.com, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org, kthota@nvidia.com,
        mmaddireddy@nvidia.com, sagar.tv@gmail.com
Subject: Re: [PATCH V1] PCI: dwc: Fixes N_FTS setup
Message-ID: <20220919172916.GA1012108@bhelgaas>
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In-Reply-To: <20220919143123.28250-1-vidyas@nvidia.com>
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In subject, "Fix" (not "Fixes") so it's an imperative verb.  Maybe
"Fix n_fts[] array overrun" to be more specific.

On Mon, Sep 19, 2022 at 08:01:23PM +0530, Vidya Sagar wrote:
> commit aeaa0bfe89654 ("PCI: dwc: Move N_FTS setup to common setup")
> unnecessarily uses pci->link_gen in deriving the index to the

Not just "unnecessarily"; using pci->link_gen is *incorrect* since
only [0] and [1] are defined.

> n_fts[] array also introducing the issue of accessing beyond the
> boundaries of array for greater than Gen-2 speeds. This change fixes
> that issue.
> 
> Fixes: aeaa0bfe8965 ("PCI: dwc: Move N_FTS setup to common setup")
> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index c6725c519a47..9e4d96e5a3f5 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -641,7 +641,7 @@ void dw_pcie_setup(struct dw_pcie *pci)
>  	if (pci->n_fts[1]) {
>  		val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
>  		val &= ~PORT_LOGIC_N_FTS_MASK;
> -		val |= pci->n_fts[pci->link_gen - 1];
> +		val |= pci->n_fts[1];
>  		dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
>  	}
>  
> -- 
> 2.17.1
>