diff mbox series

[v2,3/4] wifi: ath12k: fix source ring-buffer corruption

Message ID 20250604144509.28374-4-johan+linaro@kernel.org
State Superseded
Headers show
Series wifi: ath12k: fix dest ring-buffer corruption | expand

Commit Message

Johan Hovold June 4, 2025, 2:45 p.m. UTC 
Add the missing memory barrier to make sure that LMAC source ring
descriptors are written before updating the head pointer to avoid
passing stale data to the firmware on weakly ordered architectures like
aarch64.

Note that non-LMAC rings use MMIO write accessors which have the
required write memory barrier.

Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Cc: stable@vger.kernel.org      # 6.3
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/net/wireless/ath/ath12k/hal.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
index 8615578bb802..1e2d13cc2d19 100644
--- a/drivers/net/wireless/ath/ath12k/hal.c
+++ b/drivers/net/wireless/ath/ath12k/hal.c
@@ -2161,7 +2161,11 @@  void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
 		if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
 			srng->u.src_ring.last_tp =
 				*(volatile u32 *)srng->u.src_ring.tp_addr;
-			*srng->u.src_ring.hp_addr = srng->u.src_ring.hp;
+			/* Make sure descriptor is written before updating the
+			 * head pointer.
+			 */
+			dma_wmb();
+			WRITE_ONCE(*srng->u.src_ring.hp_addr, srng->u.src_ring.hp);
 		} else {
 			srng->u.dst_ring.last_hp = *srng->u.dst_ring.hp_addr;
 			*srng->u.dst_ring.tp_addr = srng->u.dst_ring.tp;
@@ -2170,6 +2174,10 @@  void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
 		if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
 			srng->u.src_ring.last_tp =
 				*(volatile u32 *)srng->u.src_ring.tp_addr;
+			/* Assume implementation use an MMIO write accessor
+			 * which has the required wmb() so that the descriptor
+			 * is written before the updating the head pointer.
+			 */
 			ath12k_hif_write32(ab,
 					   (unsigned long)srng->u.src_ring.hp_addr -
 					   (unsigned long)ab->mem,