Add the missing memory barrier to make sure that the REO dest ring descriptor is read after the head pointer to avoid using stale data on weakly ordered architectures like aarch64.
This may fix the ring-buffer corruption worked around by commit f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination ring") by silently discarding data, and may possibly also address user reported errors like:
ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set
Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41
Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices") Cc: stable@vger.kernel.org # 5.6 Link: https://bugzilla.kernel.org/show_bug.cgi?id=218005 Signed-off-by: Johan Hovold johan+linaro@kernel.org ---
As I reported here:
https://lore.kernel.org/lkml/Z9G5zEOcTdGKm7Ei@hovoldconsulting.com/
the ath11k and ath12k appear to be missing a number of memory barriers that are required on weakly ordered architectures like aarch64 to avoid memory corruption issues.
Here's a fix for one more such case which people already seem to be hitting.
Note that I've seen one "msdu_done" bit not set warning also with this patch so whether it helps with that at all remains to be seen. I'm CCing Jens and Steev that see these warnings frequently and that may be able to help out with testing.
Johan
drivers/net/wireless/ath/ath11k/dp_rx.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/drivers/net/wireless/ath/ath11k/dp_rx.c b/drivers/net/wireless/ath/ath11k/dp_rx.c index 029ecf51c9ef..0a57b337e4c6 100644 --- a/drivers/net/wireless/ath/ath11k/dp_rx.c +++ b/drivers/net/wireless/ath/ath11k/dp_rx.c @@ -2646,7 +2646,7 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id, struct ath11k *ar; struct hal_reo_dest_ring *desc; enum hal_reo_dest_ring_push_reason push_reason; - u32 cookie; + u32 cookie, info0, rx_msdu_info0, rx_mpdu_info0; int i;
for (i = 0; i < MAX_RADIOS; i++) @@ -2659,11 +2659,14 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id, try_again: ath11k_hal_srng_access_begin(ab, srng);
+ /* Make sure descriptor is read after the head pointer. */ + dma_rmb(); + while (likely(desc = (struct hal_reo_dest_ring *)ath11k_hal_srng_dst_get_next_entry(ab, srng))) { cookie = FIELD_GET(BUFFER_ADDR_INFO1_SW_COOKIE, - desc->buf_addr_info.info1); + READ_ONCE(desc->buf_addr_info.info1)); buf_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_BUF_ID, cookie); mac_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_PDEV_ID, cookie); @@ -2692,8 +2695,9 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
num_buffs_reaped[mac_id]++;
+ info0 = READ_ONCE(desc->info0); push_reason = FIELD_GET(HAL_REO_DEST_RING_INFO0_PUSH_REASON, - desc->info0); + info0); if (unlikely(push_reason != HAL_REO_DEST_RING_PUSH_REASON_ROUTING_INSTRUCTION)) { dev_kfree_skb_any(msdu); @@ -2701,18 +2705,21 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id, continue; }
- rxcb->is_first_msdu = !!(desc->rx_msdu_info.info0 & + rx_msdu_info0 = READ_ONCE(desc->rx_msdu_info.info0); + rx_mpdu_info0 = READ_ONCE(desc->rx_mpdu_info.info0); + + rxcb->is_first_msdu = !!(rx_msdu_info0 & RX_MSDU_DESC_INFO0_FIRST_MSDU_IN_MPDU); - rxcb->is_last_msdu = !!(desc->rx_msdu_info.info0 & + rxcb->is_last_msdu = !!(rx_msdu_info0 & RX_MSDU_DESC_INFO0_LAST_MSDU_IN_MPDU); - rxcb->is_continuation = !!(desc->rx_msdu_info.info0 & + rxcb->is_continuation = !!(rx_msdu_info0 & RX_MSDU_DESC_INFO0_MSDU_CONTINUATION); rxcb->peer_id = FIELD_GET(RX_MPDU_DESC_META_DATA_PEER_ID, - desc->rx_mpdu_info.meta_data); + READ_ONCE(desc->rx_mpdu_info.meta_data)); rxcb->seq_no = FIELD_GET(RX_MPDU_DESC_INFO0_SEQ_NUM, - desc->rx_mpdu_info.info0); + rx_mpdu_info0); rxcb->tid = FIELD_GET(HAL_REO_DEST_RING_INFO0_RX_QUEUE_NUM, - desc->info0); + info0);
rxcb->mac_id = mac_id; __skb_queue_tail(&msdu_list[mac_id], msdu);