From: Sergey Ryazanov Date: Wed, 22 Jan 2025 22:26:51 +0000 (+0200) Subject: kernel: vrx518_tc: fix RX desc phys to virt mapping X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=7bd579689d2304c73c263be3e030d76c551d6e87;p=openwrt%2Fstaging%2Fsvanheule.git kernel: vrx518_tc: fix RX desc phys to virt mapping It looks like VRX518 returns phys addr of data buffer in the 'data_ptr' field of the RX descriptor and an actual data offset within the buffer in the 'byte_off' field. In order to map the phys address back to virtual we need the original phys address of the allocated buffer. In the same driver applies offset to phys address before the mapping, what leads to WARN_ON triggering in plat_mem_virt() function with subsequent kernel panic: WARNING: CPU: 0 PID: 0 at .../sw_plat.c:764 0xbf306cd0 [vrx518_tc@8af9f5d0+0x25000] ... Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = aff5701e [00000000] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Noticed in ATM mode, when chip always returns byte_off = 4. In order to fix the issue, pass the phys address to plat_mem_virt() as is and apply byte_off later for proper DMA syncing and on mapped virtual address when copying RXed data into the skb. Run tested with FRITZ!Box 7530 on both ADSL and VDSL (thanks Jan) links. Fixes: 474bbe23b7 ("kernel: add Intel/Lantiq VRX518 TC driver") Tested-by: Jan Hoffmann # VDSL link Reported-and-tested-by: nebibigon93@yandex.ru # ADSL link Signed-off-by: Sergey Ryazanov Link: https://patchwork.ozlabs.org/project/openwrt/patch/20250122222654.21833-2-ryazanov.s.a@gmail.com/ Signed-off-by: Hauke Mehrtens --- diff --git a/package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch b/package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch index edc97998b7..6596a8b913 100644 --- a/package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch +++ b/package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch @@ -855,12 +855,12 @@ This replaces it by a basic working implementation. - continue; + + // this seems to be a pointer to a DS PKT buffer -+ phyaddr = desc->data_ptr + desc->byte_off; ++ phyaddr = desc->data_ptr; + ptr = plat_mem_virt(phyaddr); -+ + len = desc->data_len; + -+ dma_sync_single_range_for_cpu(pdev, phyaddr, 0, len, DMA_FROM_DEVICE); ++ dma_sync_single_for_cpu(pdev, phyaddr, desc->byte_off + len, ++ DMA_FROM_DEVICE); + + skb = netdev_alloc_skb(g_plat_priv->netdev, len); + if (unlikely(!skb)) { @@ -871,7 +871,7 @@ This replaces it by a basic working implementation. - ring_idx_inc(rxout, idx); + + dst = skb_put(skb, len); -+ memcpy(dst, ptr, len); ++ memcpy(dst, ptr + desc->byte_off, len); + + priv->tc_ops.recv(g_plat_priv->netdev, skb); +