From: Lothar Waßmann
> commit 1b7bde6d659d ("net: fec: implement rx_copybreak to improve rx
> performance")
> introduced a regression for i.MX28. The swap_buffer() function doing
> the endian conversion of the received data on i.MX28 may access memory
> beyond the actual packet size in the DMA buffer. fec_enet_copybreak()
> does not copy those bytes, so that the last bytes of a packet may be
> filled with invalid data after swapping.
> This will likely lead to checksum errors on received packets.
> E.g. when trying to mount an NFS rootfs:
> UDP: bad checksum. From 192.168.1.225:111 to 192.168.100.73:44662 ulen 36
>
> Do the byte swapping and copying to the new skb in one go if
> necessary.
ISTM that if you need to do the 'swap' you should copy the data regardless
of the length.
David
>
> Signed-off-by: Lothar Wamann <l...@karo-electronics.de>
> ---
> drivers/net/ethernet/freescale/fec_main.c | 25 +++++++++++++++++++++----
> 1 file changed, 21 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index 87975b5..eaaebad 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -339,6 +339,18 @@ static void *swap_buffer(void *bufaddr, int len)
> return bufaddr;
> }
>
> +static void *swap_buffer2(void *dst_buf, void *src_buf, int len)
> +{
> + int i;
> + unsigned int *src = src_buf;
> + unsigned int *dst = dst_buf;
> +
> + for (i = 0; i < DIV_ROUND_UP(len, 4); i++, src++, dst++)
> + *dst = cpu_to_be32(*src);
> +
> + return dst_buf;
> +}
> +
> static void fec_dump(struct net_device *ndev)
> {
> struct fec_enet_private *fep = netdev_priv(ndev);
> @@ -1348,7 +1360,7 @@ fec_enet_new_rxbdp(struct net_device *ndev, struct
> bufdesc *bdp, struct sk_buff
> }
>
> static bool fec_enet_copybreak(struct net_device *ndev, struct sk_buff **skb,
> - struct bufdesc *bdp, u32 length)
> + struct bufdesc *bdp, u32 length, int swap)
> {
> struct fec_enet_private *fep = netdev_priv(ndev);
> struct sk_buff *new_skb;
> @@ -1363,7 +1375,10 @@ static bool fec_enet_copybreak(struct net_device
> *ndev, struct sk_buff **skb,
> dma_sync_single_for_cpu(&fep->pdev->dev, bdp->cbd_bufaddr,
> FEC_ENET_RX_FRSIZE - fep->rx_align,
> DMA_FROM_DEVICE);
> - memcpy(new_skb->data, (*skb)->data, length);
> + if (!swap)
> + memcpy(new_skb->data, (*skb)->data, length);
> + else
> + swap_buffer2(new_skb->data, (*skb)->data, length);
> *skb = new_skb;
>
> return true;
> @@ -1393,6 +1408,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget,
> u16 queue_id)
> u16 vlan_tag;
> int index = 0;
> bool is_copybreak;
> + bool need_swap = id_entry->driver_data & FEC_QUIRK_SWAP_FRAME;
>
> #ifdef CONFIG_M532x
> flush_cache_all();
> @@ -1456,7 +1472,8 @@ fec_enet_rx_queue(struct net_device *ndev, int budget,
> u16 queue_id)
> * include that when passing upstream as it messes up
> * bridging applications.
> */
> - is_copybreak = fec_enet_copybreak(ndev, &skb, bdp, pkt_len - 4);
> + is_copybreak = fec_enet_copybreak(ndev, &skb, bdp, pkt_len - 4,
> + need_swap);
> if (!is_copybreak) {
> skb_new = netdev_alloc_skb(ndev, FEC_ENET_RX_FRSIZE);
> if (unlikely(!skb_new)) {
> @@ -1471,7 +1488,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget,
> u16 queue_id)
> prefetch(skb->data - NET_IP_ALIGN);
> skb_put(skb, pkt_len - 4);
> data = skb->data;
> - if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
> + if (!is_copybreak && need_swap)
> swap_buffer(data, pkt_len);
>
> /* Extract the enhanced buffer descriptor */
> --
> 1.7.10.4
>
> --
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