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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        Ard Biesheuvel <ardb@kernel.org>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.16 1019/1039] net: cpsw: avoid alignment faults by taking NET_IP_ALIGN into account
Date:   Mon, 24 Jan 2022 19:46:48 +0100
Message-Id: <20220124184159.548689447@linuxfoundation.org>
In-Reply-To: <20220124184125.121143506@linuxfoundation.org>
References: <20220124184125.121143506@linuxfoundation.org>
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From: Ard Biesheuvel <ardb@kernel.org>

commit 1771afd47430f5e95c9c3a2e3a8a63e67402d3fe upstream.

Both versions of the CPSW driver declare a CPSW_HEADROOM_NA macro that
takes NET_IP_ALIGN into account, but fail to use it appropriately when
storing incoming packets in memory. This results in the IPv4 source and
destination addresses to appear misaligned in memory, which causes
aligment faults that need to be fixed up in software.

So let's switch from CPSW_HEADROOM to CPSW_HEADROOM_NA where needed.
This gets rid of any alignment faults on the RX path on a Beaglebone
White.

Fixes: 9ed4050c0d75 ("net: ethernet: ti: cpsw: add XDP support")
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/ti/cpsw.c      |    6 +++---
 drivers/net/ethernet/ti/cpsw_new.c  |    6 +++---
 drivers/net/ethernet/ti/cpsw_priv.c |    2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -349,7 +349,7 @@ static void cpsw_rx_handler(void *token,
 	struct cpsw_common	*cpsw = ndev_to_cpsw(xmeta->ndev);
 	int			pkt_size = cpsw->rx_packet_max;
 	int			ret = 0, port, ch = xmeta->ch;
-	int			headroom = CPSW_HEADROOM;
+	int			headroom = CPSW_HEADROOM_NA;
 	struct net_device	*ndev = xmeta->ndev;
 	struct cpsw_priv	*priv;
 	struct page_pool	*pool;
@@ -392,7 +392,7 @@ static void cpsw_rx_handler(void *token,
 	}
 
 	if (priv->xdp_prog) {
-		int headroom = CPSW_HEADROOM, size = len;
+		int size = len;
 
 		xdp_init_buff(&xdp, PAGE_SIZE, &priv->xdp_rxq[ch]);
 		if (status & CPDMA_RX_VLAN_ENCAP) {
@@ -442,7 +442,7 @@ requeue:
 	xmeta->ndev = ndev;
 	xmeta->ch = ch;
 
-	dma = page_pool_get_dma_addr(new_page) + CPSW_HEADROOM;
+	dma = page_pool_get_dma_addr(new_page) + CPSW_HEADROOM_NA;
 	ret = cpdma_chan_submit_mapped(cpsw->rxv[ch].ch, new_page, dma,
 				       pkt_size, 0);
 	if (ret < 0) {
--- a/drivers/net/ethernet/ti/cpsw_new.c
+++ b/drivers/net/ethernet/ti/cpsw_new.c
@@ -283,7 +283,7 @@ static void cpsw_rx_handler(void *token,
 {
 	struct page *new_page, *page = token;
 	void *pa = page_address(page);
-	int headroom = CPSW_HEADROOM;
+	int headroom = CPSW_HEADROOM_NA;
 	struct cpsw_meta_xdp *xmeta;
 	struct cpsw_common *cpsw;
 	struct net_device *ndev;
@@ -336,7 +336,7 @@ static void cpsw_rx_handler(void *token,
 	}
 
 	if (priv->xdp_prog) {
-		int headroom = CPSW_HEADROOM, size = len;
+		int size = len;
 
 		xdp_init_buff(&xdp, PAGE_SIZE, &priv->xdp_rxq[ch]);
 		if (status & CPDMA_RX_VLAN_ENCAP) {
@@ -386,7 +386,7 @@ requeue:
 	xmeta->ndev = ndev;
 	xmeta->ch = ch;
 
-	dma = page_pool_get_dma_addr(new_page) + CPSW_HEADROOM;
+	dma = page_pool_get_dma_addr(new_page) + CPSW_HEADROOM_NA;
 	ret = cpdma_chan_submit_mapped(cpsw->rxv[ch].ch, new_page, dma,
 				       pkt_size, 0);
 	if (ret < 0) {
--- a/drivers/net/ethernet/ti/cpsw_priv.c
+++ b/drivers/net/ethernet/ti/cpsw_priv.c
@@ -1120,7 +1120,7 @@ int cpsw_fill_rx_channels(struct cpsw_pr
 			xmeta->ndev = priv->ndev;
 			xmeta->ch = ch;
 
-			dma = page_pool_get_dma_addr(page) + CPSW_HEADROOM;
+			dma = page_pool_get_dma_addr(page) + CPSW_HEADROOM_NA;
 			ret = cpdma_chan_idle_submit_mapped(cpsw->rxv[ch].ch,
 							    page, dma,
 							    cpsw->rx_packet_max,