Normalize ppm to an unsigned magnitude before using it in the increment value scaling path.
This avoids negating INT64_MIN and also prevents subtracting 62 from the reduced log sum unless the sum is still above the overflow threshold reported by Coverity. Coverity issue: 501832 Signed-off-by: Soumyadeep Hore <[email protected]> --- drivers/net/intel/idpf/idpf_ethdev.c | 32 +++++++++++++++++----------- 1 file changed, 20 insertions(+), 12 deletions(-) diff --git a/drivers/net/intel/idpf/idpf_ethdev.c b/drivers/net/intel/idpf/idpf_ethdev.c index 5e57a45775..1c5bd2ee12 100644 --- a/drivers/net/intel/idpf/idpf_ethdev.c +++ b/drivers/net/intel/idpf/idpf_ethdev.c @@ -1007,7 +1007,7 @@ idpf_timesync_adjust_freq(struct rte_eth_dev *dev, int64_t ppm) struct idpf_ptp *ptp = adapter->ptp; int64_t incval, diff = 0; bool negative = false; - uint64_t div, rem; + uint64_t abs_ppm, div, rem; uint64_t divisor = 1000000ULL << 16; int shift; int ret; @@ -1016,26 +1016,34 @@ idpf_timesync_adjust_freq(struct rte_eth_dev *dev, int64_t ppm) if (ppm < 0) { negative = true; - ppm = -ppm; + abs_ppm = ppm == INT64_MIN ? (uint64_t)INT64_MAX + 1 : + (uint64_t)(-ppm); + } else { + abs_ppm = (uint64_t)ppm; } /* can incval * ppm overflow ? */ - if (rte_log2_u64(incval) + rte_log2_u64(ppm) > 62) { - rem = ppm % divisor; - div = ppm / divisor; + if (rte_log2_u64(incval) + rte_log2_u64(abs_ppm) > 62) { + rem = abs_ppm % divisor; + div = abs_ppm / divisor; diff = div * incval; - ppm = rem; + abs_ppm = rem; + + if (abs_ppm != 0) { + uint32_t log_sum; - shift = rte_log2_u64(incval) + rte_log2_u64(ppm) - 62; - if (shift > 0) { - /* drop precision */ - ppm >>= shift; - divisor >>= shift; + log_sum = rte_log2_u64(incval) + rte_log2_u64(abs_ppm); + if (log_sum > 62) { + shift = log_sum - 62; + /* drop precision */ + abs_ppm >>= shift; + divisor >>= shift; + } } } if (divisor) - diff = diff + incval * ppm / divisor; + diff = diff + incval * abs_ppm / divisor; if (negative) incval -= diff; -- 2.47.1
