From 6efa0df54022c6c9fd4d294b87622c7fcdc418c8 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 4 Jun 2025 16:34:56 +0200 Subject: [PATCH] wifi: ath11k: fix source ring-buffer corruption 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: 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 Signed-off-by: Johan Hovold Reviewed-by: Baochen Qiang Link: https://patch.msgid.link/20250604143457.26032-5-johan+linaro@kernel.org Signed-off-by: Jeff Johnson --- drivers/net/wireless/ath/ath11k/hal.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath11k/hal.c b/drivers/net/wireless/ath/ath11k/hal.c index 4a3bdacc57695..28f94c36d304a 100644 --- a/drivers/net/wireless/ath/ath11k/hal.c +++ b/drivers/net/wireless/ath/ath11k/hal.c @@ -864,7 +864,11 @@ void ath11k_hal_srng_access_end(struct ath11k_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; @@ -873,6 +877,10 @@ void ath11k_hal_srng_access_end(struct ath11k_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. + */ ath11k_hif_write32(ab, (unsigned long)srng->u.src_ring.hp_addr - (unsigned long)ab->mem, -- 2.47.3