From: Bjorn Helgaas <helgaas@kernel.org>
To: Jon Hunter <jonathanh@nvidia.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Thierry Reding <thierry.reding@gmail.com>,
Vidya Sagar <vidyas@nvidia.com>,
linux-pci@vger.kernel.org, linux-tegra@vger.kernel.org
Subject: Re: [PATCH] PCI: tegra: Fix shiftTooManyBitsSigned warning for Tegra194
Date: Fri, 18 Jun 2021 18:04:28 -0500 [thread overview]
Message-ID: <20210618230428.GA3231877@bjorn-Precision-5520> (raw)
In-Reply-To: <20210618160219.303092-1-jonathanh@nvidia.com>
On Fri, Jun 18, 2021 at 05:02:19PM +0100, Jon Hunter wrote:
> The cppcheck tool issues the following warning for the Tegra194 PCIe
> driver ...
>
> $ cppcheck --enable=all drivers/pci/controller/dwc/pcie-tegra194.c
> Checking drivers/pci/controller/dwc/pcie-tegra194.c ...
>
> drivers/pci/controller/dwc/pcie-tegra194.c:1829:23: portability:
> Shifting signed 32-bit value by 31 bits is
> implementation-defined behaviour. See condition at line 1826.
> [shiftTooManyBitsSigned]
>
> appl_writel(pcie, (1 << irq), APPL_MSI_CTRL_1);
> ^
> The above warning occurs because the '1' is treated as a signed type
> and so fix this by using the 'BIT' macro to ensure that this is defined
> as a unsigned type.
The subject and commit log should describe the problem we're fixing.
The *warning* is not the problem; the problem is the undefined
behavior.
I'll fix this up, no need to repost for this.
> Fixes: c57247f940e8 PCI: tegra: Add support for PCIe endpoint mode in Tegra194
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> ---
> drivers/pci/controller/dwc/pcie-tegra194.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index 8fc08336f76e..3c1feeab104f 100644
> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -1826,7 +1826,7 @@ static int tegra_pcie_ep_raise_msi_irq(struct tegra_pcie_dw *pcie, u16 irq)
> if (unlikely(irq > 31))
> return -EINVAL;
>
> - appl_writel(pcie, (1 << irq), APPL_MSI_CTRL_1);
> + appl_writel(pcie, BIT(irq), APPL_MSI_CTRL_1);
>
> return 0;
> }
> --
> 2.25.1
>
next prev parent reply other threads:[~2021-06-18 23:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-18 16:02 [PATCH] PCI: tegra: Fix shiftTooManyBitsSigned warning for Tegra194 Jon Hunter
2021-06-18 16:05 ` Jon Hunter
2021-06-18 23:04 ` Bjorn Helgaas [this message]
2021-06-23 8:52 ` Lorenzo Pieralisi
2021-06-23 12:04 ` Bjorn Helgaas
2021-06-24 23:01 ` Bjorn Helgaas
2021-06-25 9:08 ` Lorenzo Pieralisi
2021-06-23 15:23 ` Lorenzo Pieralisi
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