[PATCH 5.10 173/243] PCI: tegra194: Fix tegra_pcie_ep_raise_msi_irq() ill-defined shift

Greg Kroah-Hartman
2021-07-19T17:17:29Z

From: Jon Hunter <jonathanh@nvidia.com>

[ Upstream commit f67092eff2bd40650aad54a1a1910160f41d864a ]

tegra_pcie_ep_raise_msi_irq() shifted a signed 32-bit value left by 31
bits. The behavior of this is implementation-defined.

Replace the shift by BIT(), which is well-defined.

Found by cppcheck:

$ 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);
^

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20210618160219.303092-1-jonathanh@nvidia.com
Fixes: c57247f940e8 ("PCI: tegra: Add support for PCIe endpoint mode in Tegra194")
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 d788f4d7f9aa..506f6a294eac 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1841,7 +1841,7 @@ 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;
}
--
2.30.2