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liquidio: Fix unintentional sign extension issue on left shift of u16

Message ID 20210714152343.144795-1-colin.king@canonical.com (mailing list archive)
State Accepted
Commit e7efc2ce3d0789cd7c21b70ff00cd7838d382639
Delegated to: Netdev Maintainers
Headers show
Series liquidio: Fix unintentional sign extension issue on left shift of u16 | expand

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netdev/checkpatch warning WARNING: line length of 82 exceeds 80 columns
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Commit Message

Colin King July 14, 2021, 3:23 p.m. UTC 
From: Colin Ian King <colin.king@canonical.com>

Shifting the u16 integer oct->pcie_port by CN23XX_PKT_INPUT_CTL_MAC_NUM_POS
(29) bits will be promoted to a 32 bit signed int and then sign-extended
to a u64. In the cases where oct->pcie_port where bit 2 is set (e.g. 3..7)
the shifted value will be sign extended and the top 32 bits of the result
will be set.

Fix this by casting the u16 values to a u64 before the 29 bit left shift.

Addresses-Coverity: ("Unintended sign extension")

Fixes: 3451b97cce2d ("liquidio: CN23XX register setup")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

patchwork-bot+netdevbpf@kernel.org July 15, 2021, 5:40 p.m. UTC | #1 
Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Wed, 14 Jul 2021 16:23:43 +0100 you wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Shifting the u16 integer oct->pcie_port by CN23XX_PKT_INPUT_CTL_MAC_NUM_POS
> (29) bits will be promoted to a 32 bit signed int and then sign-extended
> to a u64. In the cases where oct->pcie_port where bit 2 is set (e.g. 3..7)
> the shifted value will be sign extended and the top 32 bits of the result
> will be set.
> 
> [...]

Here is the summary with links:
  - liquidio: Fix unintentional sign extension issue on left shift of u16
    https://git.kernel.org/netdev/net/c/e7efc2ce3d07

You are awesome, thank you!
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diff mbox series

Patch

diff --git a/drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c b/drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c
index 4cddd628d41b..9ed3d1ab2ca5 100644
--- a/drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c
+++ b/drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c
@@ -420,7 +420,7 @@  static int cn23xx_pf_setup_global_input_regs(struct octeon_device *oct)
 	 * bits 32:47 indicate the PVF num.
 	 */
 	for (q_no = 0; q_no < ern; q_no++) {
-		reg_val = oct->pcie_port << CN23XX_PKT_INPUT_CTL_MAC_NUM_POS;
+		reg_val = (u64)oct->pcie_port << CN23XX_PKT_INPUT_CTL_MAC_NUM_POS;
 
 		/* for VF assigned queues. */
 		if (q_no < oct->sriov_info.pf_srn) {