Message-Id: <1536742958-29887-3-git-send-email-ilias.apalodimas@linaro.org>
Date:   Wed, 12 Sep 2018 12:02:38 +0300
From:   Ilias Apalodimas <ilias.apalodimas@...aro.org>
To:     netdev@...r.kernel.org, jaswinder.singh@...aro.org
Cc:     ard.biesheuvel@...aro.org, masami.hiramatsu@...aro.org,
        arnd@...db.de, mykyta.iziumtsev@...aro.org, bjorn.topel@...el.com,
        magnus.karlsson@...el.com, brouer@...hat.com, daniel@...earbox.net,
        ast@...nel.org, Ilias Apalodimas <ilias.apalodimas@...aro.org>
Subject: [net-next, PATCH 2/2, v2] net: socionext: add XDP support

Add basic XDP support

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@...aro.org>
---
 drivers/net/ethernet/socionext/netsec.c | 234 +++++++++++++++++++++++++++++---
 1 file changed, 216 insertions(+), 18 deletions(-)

diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
index 666fee2..1f4594f 100644
--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -9,6 +9,9 @@
 #include <linux/etherdevice.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/netlink.h>
+#include <linux/bpf.h>
+#include <linux/bpf_trace.h>
 
 #include <net/tcp.h>
 #include <net/ip6_checksum.h>
@@ -238,6 +241,11 @@
 
 #define NETSEC_F_NETSEC_VER_MAJOR_NUM(x)	((x) & 0xffff0000)
 
+#define NETSEC_XDP_PASS          0
+#define NETSEC_XDP_CONSUMED      BIT(0)
+#define NETSEC_XDP_TX            BIT(1)
+#define NETSEC_XDP_REDIR         BIT(2)
+
 enum ring_id {
 	NETSEC_RING_TX = 0,
 	NETSEC_RING_RX
@@ -256,11 +264,14 @@ struct netsec_desc_ring {
 	void *vaddr;
 	u16 pkt_cnt;
 	u16 head, tail;
+	bool is_xdp;
+	struct xdp_rxq_info xdp_rxq;
 };
 
 struct netsec_priv {
 	struct netsec_desc_ring desc_ring[NETSEC_RING_MAX];
 	struct ethtool_coalesce et_coalesce;
+	struct bpf_prog *xdp_prog;
 	spinlock_t reglock; /* protect reg access */
 	struct napi_struct napi;
 	phy_interface_t phy_interface;
@@ -297,6 +308,8 @@ struct netsec_rx_pkt_info {
 };
 
 static void netsec_rx_fill(struct netsec_priv *priv, u16 from, u16 num);
+static u32 netsec_run_xdp(struct netsec_desc *desc, struct netsec_priv *priv,
+			  struct bpf_prog *prog, struct xdp_buff *xdp);
 
 static void *netsec_alloc_rx_data(struct netsec_priv *priv,
 				  dma_addr_t *dma_addr, u16 *len);
@@ -613,13 +626,23 @@ static int netsec_clean_tx_dring(struct netsec_priv *priv, int budget)
 
 		eop = (entry->attr >> NETSEC_TX_LAST) & 1;
 
-		dma_unmap_single(priv->dev, desc->dma_addr, desc->len,
-				 DMA_TO_DEVICE);
-		if (eop) {
-			pkts++;
+		if (desc->skb)
+			dma_unmap_single(priv->dev,
+					 desc->dma_addr - XDP_PACKET_HEADROOM,
+					 desc->len, DMA_TO_DEVICE);
+
+		if (!eop) {
+			*desc = (struct netsec_desc){};
+			continue;
+		}
+
+		if (!desc->skb) {
+			skb_free_frag(desc->addr);
+		} else {
 			bytes += desc->skb->len;
 			dev_kfree_skb(desc->skb);
 		}
+		pkts++;
 		*desc = (struct netsec_desc){};
 	}
 	dring->pkt_cnt -= budget;
@@ -659,19 +682,22 @@ static void nsetsec_adv_desc(u16 *idx)
 static int netsec_process_rx(struct netsec_priv *priv, int budget)
 {
 	struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];
+	struct bpf_prog *xdp_prog = READ_ONCE(priv->xdp_prog);
 	struct net_device *ndev = priv->ndev;
-	struct sk_buff *skb;
+	struct sk_buff *skb = NULL;
+	u32 xdp_flush = 0;
+	u32 xdp_result;
 	int done = 0;
 
 	while (done < budget) {
 		u16 idx = dring->tail;
 		struct netsec_de *de = dring->vaddr + (DESC_SZ * idx);
 		struct netsec_desc *desc = &dring->desc[idx];
+		dma_addr_t dma_handle, dma_unmap;
 		struct netsec_rx_pkt_info rpi;
-		dma_addr_t dma_handle;
+		u16 pkt_len, desc_len;
+		struct xdp_buff xdp;
 		void *buf_addr;
-		u16 pkt_len;
-		u16 desc_len;
 
 		if (de->attr & (1U << NETSEC_RX_PKT_OWN_FIELD))
 			break;
@@ -704,10 +730,40 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
 
 		prefetch(desc->addr);
 		buf_addr = netsec_alloc_rx_data(priv, &dma_handle, &desc_len);
+
 		if (unlikely(!buf_addr))
 			break;
 
-		skb = build_skb(desc->addr, desc->len);
+		dma_unmap = dring->is_xdp ?
+			desc->dma_addr - XDP_PACKET_HEADROOM : desc->dma_addr;
+
+		xdp.data_hard_start = desc->addr;
+		xdp.data = desc->addr;
+		xdp_set_data_meta_invalid(&xdp);
+		xdp.data_end = xdp.data + pkt_len;
+		xdp.rxq = &dring->xdp_rxq;
+
+		if (xdp_prog) {
+			xdp.data = desc->addr + XDP_PACKET_HEADROOM;
+			xdp.data_end = xdp.data + pkt_len;
+			xdp_result = netsec_run_xdp(desc, priv, xdp_prog, &xdp);
+			if (xdp_result != NETSEC_XDP_PASS) {
+				xdp_flush |= xdp_result & NETSEC_XDP_REDIR;
+
+				dma_unmap_single_attrs(priv->dev, dma_unmap,
+						       desc->len, DMA_TO_DEVICE,
+						       DMA_ATTR_SKIP_CPU_SYNC);
+
+				desc->len = desc_len;
+				desc->dma_addr = dma_handle;
+				desc->addr = buf_addr;
+				netsec_rx_fill(priv, idx, 1);
+				nsetsec_adv_desc(&dring->tail);
+				continue;
+			}
+		}
+
+		skb = build_skb(xdp.data_hard_start, desc->len);
 		if (unlikely(!skb)) {
 			dma_unmap_single(priv->dev, dma_handle, desc_len,
 					 DMA_TO_DEVICE);
@@ -716,7 +772,7 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
 				  "rx failed to alloc skb\n");
 			break;
 		}
-		dma_unmap_single_attrs(priv->dev, desc->dma_addr, desc->len,
+		dma_unmap_single_attrs(priv->dev, dma_unmap, desc->len,
 				       DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
 
 		/* Update the descriptor with fresh buffers */
@@ -724,7 +780,8 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
 		desc->dma_addr = dma_handle;
 		desc->addr = buf_addr;
 
-		skb_put(skb, pkt_len);
+		skb_reserve(skb, xdp.data - xdp.data_hard_start);
+		skb_put(skb, xdp.data_end - xdp.data);
 		skb->protocol = eth_type_trans(skb, priv->ndev);
 
 		if (priv->rx_cksum_offload_flag &&
@@ -733,13 +790,16 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
 
 		if (napi_gro_receive(&priv->napi, skb) != GRO_DROP) {
 			ndev->stats.rx_packets++;
-			ndev->stats.rx_bytes += pkt_len;
+			ndev->stats.rx_bytes += xdp.data_end - xdp.data;
 		}
 
 		netsec_rx_fill(priv, idx, 1);
 		nsetsec_adv_desc(&dring->tail);
 	}
 
+	if (xdp_flush & NETSEC_XDP_REDIR)
+		xdp_do_flush_map();
+
 	return done;
 }
 
@@ -892,6 +952,9 @@ static void netsec_uninit_pkt_dring(struct netsec_priv *priv, int id)
 	if (!dring->vaddr || !dring->desc)
 		return;
 
+	if (xdp_rxq_info_is_reg(&dring->xdp_rxq))
+		xdp_rxq_info_unreg(&dring->xdp_rxq);
+
 	for (idx = 0; idx < DESC_NUM; idx++) {
 		desc = &dring->desc[idx];
 		if (!desc->addr)
@@ -931,11 +994,14 @@ static void netsec_free_dring(struct netsec_priv *priv, int id)
 static void *netsec_alloc_rx_data(struct netsec_priv *priv,
 				  dma_addr_t *dma_handle, u16 *desc_len)
 {
+	struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];
 	size_t len = priv->ndev->mtu + ETH_HLEN + VLAN_HLEN * 2 + NET_SKB_PAD +
 		NET_IP_ALIGN;
 	dma_addr_t mapping;
 	void *buf;
 
+	if (dring->is_xdp)
+		len += XDP_PACKET_HEADROOM;
 	len = SKB_DATA_ALIGN(len);
 	len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 
@@ -943,11 +1009,12 @@ static void *netsec_alloc_rx_data(struct netsec_priv *priv,
 	if (!buf)
 		return NULL;
 
-	mapping = dma_map_single(priv->dev, buf, len, DMA_FROM_DEVICE);
+	mapping = dma_map_single(priv->dev, buf, len,
+				 DMA_FROM_DEVICE);
 	if (unlikely(dma_mapping_error(priv->dev, mapping)))
 		goto err_out;
 
-	*dma_handle = mapping;
+	*dma_handle = mapping + (dring->is_xdp ? XDP_PACKET_HEADROOM : 0);
 	*desc_len = len;
 
 	return buf;
@@ -994,7 +1061,13 @@ static int netsec_alloc_dring(struct netsec_priv *priv, enum ring_id id)
 static int netsec_setup_rx_dring(struct netsec_priv *priv)
 {
 	struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];
-	int i;
+	struct bpf_prog *xdp_prog = READ_ONCE(priv->xdp_prog);
+	int i, err;
+
+	if (xdp_prog)
+		dring->is_xdp = true;
+	else
+		dring->is_xdp = false;
 
 	for (i = 0; i < DESC_NUM; i++) {
 		struct netsec_desc *desc = &dring->desc[i];
@@ -1003,20 +1076,29 @@ static int netsec_setup_rx_dring(struct netsec_priv *priv)
 		u16 len;
 
 		buf = netsec_alloc_rx_data(priv, &dma_handle, &len);
-		if (!buf) {
-			netsec_uninit_pkt_dring(priv, NETSEC_RING_RX);
+		if (!buf)
 			goto err_out;
-		}
 		desc->dma_addr = dma_handle;
 		desc->addr = buf;
 		desc->len = len;
 	}
 
 	netsec_rx_fill(priv, 0, DESC_NUM);
+	err = xdp_rxq_info_reg(&dring->xdp_rxq, priv->ndev, 0);
+	if (err)
+		goto err_out;
+
+	err = xdp_rxq_info_reg_mem_model(&dring->xdp_rxq, MEM_TYPE_PAGE_SHARED,
+					 NULL);
+	if (err) {
+		xdp_rxq_info_unreg(&dring->xdp_rxq);
+		goto err_out;
+	}
 
 	return 0;
 
 err_out:
+	netsec_uninit_pkt_dring(priv, NETSEC_RING_RX);
 	return -ENOMEM;
 }
 
@@ -1420,6 +1502,121 @@ static int netsec_netdev_ioctl(struct net_device *ndev, struct ifreq *ifr,
 	return phy_mii_ioctl(ndev->phydev, ifr, cmd);
 }
 
+static u32 netsec_xmit_xdp(struct netsec_priv *priv, struct xdp_buff *xdp,
+			   struct netsec_desc *rx_desc)
+{
+	struct netsec_desc_ring *tx_ring = &priv->desc_ring[NETSEC_RING_TX];
+	struct netsec_tx_pkt_ctrl tx_ctrl = {};
+	struct netsec_desc tx_desc;
+	int filled;
+	u32 len;
+
+	len = xdp->data_end - xdp->data;
+
+	if (tx_ring->head >= tx_ring->tail)
+		filled = tx_ring->head - tx_ring->tail;
+	else
+		filled = tx_ring->head + DESC_NUM - tx_ring->tail;
+
+	if (DESC_NUM - filled <= 1)
+		return NETSEC_XDP_CONSUMED;
+
+	dma_sync_single_for_device(priv->dev, rx_desc->dma_addr, len,
+				   DMA_TO_DEVICE);
+
+	tx_desc.dma_addr = rx_desc->dma_addr;
+	tx_desc.addr = xdp->data;
+	tx_desc.len = len;
+
+	netsec_set_tx_de(priv, tx_ring, &tx_ctrl, &tx_desc, NULL);
+	netsec_write(priv, NETSEC_REG_NRM_TX_PKTCNT, 1);
+
+	return NETSEC_XDP_TX;
+}
+
+static u32 netsec_run_xdp(struct netsec_desc *desc, struct netsec_priv *priv,
+			  struct bpf_prog *prog, struct xdp_buff *xdp)
+{
+	u32 ret = NETSEC_XDP_PASS;
+	int err;
+	u32 act;
+
+	rcu_read_lock();
+	act = bpf_prog_run_xdp(prog, xdp);
+
+	switch (act) {
+	case XDP_PASS:
+		ret = NETSEC_XDP_PASS;
+		break;
+	case XDP_TX:
+		ret = netsec_xmit_xdp(priv, xdp, desc);
+		break;
+	case XDP_REDIRECT:
+		err = xdp_do_redirect(priv->ndev, xdp, prog);
+		if (!err) {
+			ret = NETSEC_XDP_REDIR;
+		} else {
+			ret = NETSEC_XDP_CONSUMED;
+			xdp_return_buff(xdp);
+		}
+		break;
+	default:
+		bpf_warn_invalid_xdp_action(act);
+		/* fall through */
+	case XDP_ABORTED:
+		trace_xdp_exception(priv->ndev, prog, act);
+		/* fall through -- handle aborts by dropping packet */
+	case XDP_DROP:
+		ret = NETSEC_XDP_CONSUMED;
+		break;
+	}
+
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static int netsec_xdp_setup(struct netsec_priv *priv, struct bpf_prog *prog,
+			    struct netlink_ext_ack *extack)
+{
+	struct net_device *dev = priv->ndev;
+	struct bpf_prog *old_prog;
+
+	/* For now just support only the usual MTU sized frames */
+	if (prog && dev->mtu > 1500) {
+		NL_SET_ERR_MSG_MOD(extack, "Jumbo frames not supported on XDP");
+		return -EOPNOTSUPP;
+	}
+
+	if (netif_running(dev))
+		netsec_netdev_stop(dev);
+
+	/* Detach old prog, if any */
+	old_prog = xchg(&priv->xdp_prog, prog);
+	if (old_prog)
+		bpf_prog_put(old_prog);
+
+	if (netif_running(dev))
+		netsec_netdev_open(dev);
+
+	return 0;
+}
+
+static int netsec_xdp(struct net_device *ndev, struct netdev_bpf *xdp)
+{
+	struct netsec_priv *priv = netdev_priv(ndev);
+
+	switch (xdp->command) {
+	case XDP_SETUP_PROG:
+		return netsec_xdp_setup(priv, xdp->prog, xdp->extack);
+	case XDP_QUERY_PROG:
+		xdp->prog_id = priv->xdp_prog ? priv->xdp_prog->aux->id : 0;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
 static const struct net_device_ops netsec_netdev_ops = {
 	.ndo_init		= netsec_netdev_init,
 	.ndo_uninit		= netsec_netdev_uninit,
@@ -1430,6 +1627,7 @@ static const struct net_device_ops netsec_netdev_ops = {
 	.ndo_set_mac_address    = eth_mac_addr,
 	.ndo_validate_addr	= eth_validate_addr,
 	.ndo_do_ioctl		= netsec_netdev_ioctl,
+	.ndo_bpf		= netsec_xdp,
 };
 
 static int netsec_of_probe(struct platform_device *pdev,
-- 
2.7.4

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