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

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

[Colin King]

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(-)

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) {
-- 
2.31.1

Re: [PATCH] liquidio: Fix unintentional sign extension issue on left shift of u16

[patchwork-bot+netdevbpf]

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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