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authorColin Ian King <colin.king@canonical.com>2019-06-07 19:19:20 +0100
committerJeff Kirsher <jeffrey.t.kirsher@intel.com>2019-06-28 15:59:38 -0700
commitb97c0b521ae05d40e6541858600088a30f6dbe3a (patch)
tree09b7b457bf1287f84cf3965d985e37ba2843d759 /drivers/net/ethernet/intel/ixgbe
parent92924064106e410cdc015f1dbfc0499309f9f5b1 (diff)
ixgbe: fix potential u32 overflow on shift
The u32 variable rem is being shifted using u32 arithmetic however it is being passed to div_u64 that expects the expression to be a u64. The 32 bit shift may potentially overflow, so cast rem to a u64 before shifting to avoid this. Also remove comment about overflow. Addresses-Coverity: ("Unintentional integer overflow") Fixes: cd4583206990 ("ixgbe: implement support for SDP/PPS output on X550 hardware") Fixes: 68d9676fc04e ("ixgbe: fix PTP SDP pin setup on X540 hardware") Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Andrew Bowers <andrewx.bowers@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Diffstat (limited to 'drivers/net/ethernet/intel/ixgbe')
-rw-r--r--drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c14
1 files changed, 4 insertions, 10 deletions
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
index 2c4d327fcc2e..0be13a90ff79 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
@@ -205,11 +205,8 @@ static void ixgbe_ptp_setup_sdp_X540(struct ixgbe_adapter *adapter)
*/
rem = (NS_PER_SEC - rem);
- /* Adjust the clock edge to align with the next full second. This
- * assumes that the cycle counter shift is small enough to avoid
- * overflowing when shifting the remainder.
- */
- clock_edge += div_u64((rem << cc->shift), cc->mult);
+ /* Adjust the clock edge to align with the next full second. */
+ clock_edge += div_u64(((u64)rem << cc->shift), cc->mult);
trgttiml = (u32)clock_edge;
trgttimh = (u32)(clock_edge >> 32);
@@ -291,11 +288,8 @@ static void ixgbe_ptp_setup_sdp_X550(struct ixgbe_adapter *adapter)
*/
rem = (NS_PER_SEC - rem);
- /* Adjust the clock edge to align with the next full second. This
- * assumes that the cycle counter shift is small enough to avoid
- * overflowing when shifting the remainder.
- */
- clock_edge += div_u64((rem << cc->shift), cc->mult);
+ /* Adjust the clock edge to align with the next full second. */
+ clock_edge += div_u64(((u64)rem << cc->shift), cc->mult);
/* X550 hardware stores the time in 32bits of 'billions of cycles' and
* 32bits of 'cycles'. There's no guarantee that cycles represents