cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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tag_gswip.c (2783B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Intel / Lantiq GSWIP V2.0 PMAC tag support
      4 *
      5 * Copyright (C) 2017 - 2018 Hauke Mehrtens <hauke@hauke-m.de>
      6 */
      7
      8#include <linux/bitops.h>
      9#include <linux/etherdevice.h>
     10#include <linux/skbuff.h>
     11#include <net/dsa.h>
     12
     13#include "dsa_priv.h"
     14
     15#define GSWIP_TX_HEADER_LEN		4
     16
     17/* special tag in TX path header */
     18/* Byte 0 */
     19#define GSWIP_TX_SLPID_SHIFT		0	/* source port ID */
     20#define  GSWIP_TX_SLPID_CPU		2
     21#define  GSWIP_TX_SLPID_APP1		3
     22#define  GSWIP_TX_SLPID_APP2		4
     23#define  GSWIP_TX_SLPID_APP3		5
     24#define  GSWIP_TX_SLPID_APP4		6
     25#define  GSWIP_TX_SLPID_APP5		7
     26
     27/* Byte 1 */
     28#define GSWIP_TX_CRCGEN_DIS		BIT(7)
     29#define GSWIP_TX_DPID_SHIFT		0	/* destination group ID */
     30#define  GSWIP_TX_DPID_ELAN		0
     31#define  GSWIP_TX_DPID_EWAN		1
     32#define  GSWIP_TX_DPID_CPU		2
     33#define  GSWIP_TX_DPID_APP1		3
     34#define  GSWIP_TX_DPID_APP2		4
     35#define  GSWIP_TX_DPID_APP3		5
     36#define  GSWIP_TX_DPID_APP4		6
     37#define  GSWIP_TX_DPID_APP5		7
     38
     39/* Byte 2 */
     40#define GSWIP_TX_PORT_MAP_EN		BIT(7)
     41#define GSWIP_TX_PORT_MAP_SEL		BIT(6)
     42#define GSWIP_TX_LRN_DIS		BIT(5)
     43#define GSWIP_TX_CLASS_EN		BIT(4)
     44#define GSWIP_TX_CLASS_SHIFT		0
     45#define GSWIP_TX_CLASS_MASK		GENMASK(3, 0)
     46
     47/* Byte 3 */
     48#define GSWIP_TX_DPID_EN		BIT(0)
     49#define GSWIP_TX_PORT_MAP_SHIFT		1
     50#define GSWIP_TX_PORT_MAP_MASK		GENMASK(6, 1)
     51
     52#define GSWIP_RX_HEADER_LEN	8
     53
     54/* special tag in RX path header */
     55/* Byte 7 */
     56#define GSWIP_RX_SPPID_SHIFT		4
     57#define GSWIP_RX_SPPID_MASK		GENMASK(6, 4)
     58
     59static struct sk_buff *gswip_tag_xmit(struct sk_buff *skb,
     60				      struct net_device *dev)
     61{
     62	struct dsa_port *dp = dsa_slave_to_port(dev);
     63	u8 *gswip_tag;
     64
     65	skb_push(skb, GSWIP_TX_HEADER_LEN);
     66
     67	gswip_tag = skb->data;
     68	gswip_tag[0] = GSWIP_TX_SLPID_CPU;
     69	gswip_tag[1] = GSWIP_TX_DPID_ELAN;
     70	gswip_tag[2] = GSWIP_TX_PORT_MAP_EN | GSWIP_TX_PORT_MAP_SEL;
     71	gswip_tag[3] = BIT(dp->index + GSWIP_TX_PORT_MAP_SHIFT) & GSWIP_TX_PORT_MAP_MASK;
     72	gswip_tag[3] |= GSWIP_TX_DPID_EN;
     73
     74	return skb;
     75}
     76
     77static struct sk_buff *gswip_tag_rcv(struct sk_buff *skb,
     78				     struct net_device *dev)
     79{
     80	int port;
     81	u8 *gswip_tag;
     82
     83	if (unlikely(!pskb_may_pull(skb, GSWIP_RX_HEADER_LEN)))
     84		return NULL;
     85
     86	gswip_tag = skb->data - ETH_HLEN;
     87
     88	/* Get source port information */
     89	port = (gswip_tag[7] & GSWIP_RX_SPPID_MASK) >> GSWIP_RX_SPPID_SHIFT;
     90	skb->dev = dsa_master_find_slave(dev, 0, port);
     91	if (!skb->dev)
     92		return NULL;
     93
     94	/* remove GSWIP tag */
     95	skb_pull_rcsum(skb, GSWIP_RX_HEADER_LEN);
     96
     97	return skb;
     98}
     99
    100static const struct dsa_device_ops gswip_netdev_ops = {
    101	.name = "gswip",
    102	.proto	= DSA_TAG_PROTO_GSWIP,
    103	.xmit = gswip_tag_xmit,
    104	.rcv = gswip_tag_rcv,
    105	.needed_headroom = GSWIP_RX_HEADER_LEN,
    106};
    107
    108MODULE_LICENSE("GPL");
    109MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_GSWIP);
    110
    111module_dsa_tag_driver(gswip_netdev_ops);