[PATCH 5.11 485/601] net: thunderx: Fix unintentional sign extension issue

Greg Kroah-Hartman
2021-05-12T17:56:47Z

From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit e701a25840360706fe4cf5de0015913ca19c274b ]

The shifting of the u8 integers rq->caching by 26 bits to
the left will be promoted to a 32 bit signed int and then
sign-extended to a u64. In the event that rq->caching is
greater than 0x1f then all then all the upper 32 bits of
the u64 end up as also being set because of the int
sign-extension. Fix this by casting the u8 values to a
u64 before the 26 bit left shift.

Addresses-Coverity: ("Unintended sign extension")
Fixes: 4863dea3fab0 ("net: Adding support for Cavium ThunderX network controller")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/cavium/thunder/nicvf_queues.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
index f782e6af45e9..50bbe79fb93d 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
@@ -776,7 +776,7 @@ static void nicvf_rcv_queue_config(struct nicvf *nic, struct queue_set *qs,
mbx.rq.msg = NIC_MBOX_MSG_RQ_CFG;
mbx.rq.qs_num = qs->vnic_id;
mbx.rq.rq_num = qidx;
- mbx.rq.cfg = (rq->caching << 26) | (rq->cq_qs << 19) |
+ mbx.rq.cfg = ((u64)rq->caching << 26) | (rq->cq_qs << 19) |
(rq->cq_idx << 16) | (rq->cont_rbdr_qs << 9) |
(rq->cont_qs_rbdr_idx << 8) |
(rq->start_rbdr_qs << 1) | (rq->start_qs_rbdr_idx);
--
2.30.2