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_ar9331.c (2352B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (c) 2019 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
      4 */
      5
      6
      7#include <linux/bitfield.h>
      8#include <linux/etherdevice.h>
      9
     10#include "dsa_priv.h"
     11
     12#define AR9331_HDR_LEN			2
     13#define AR9331_HDR_VERSION		1
     14
     15#define AR9331_HDR_VERSION_MASK		GENMASK(15, 14)
     16#define AR9331_HDR_PRIORITY_MASK	GENMASK(13, 12)
     17#define AR9331_HDR_TYPE_MASK		GENMASK(10, 8)
     18#define AR9331_HDR_BROADCAST		BIT(7)
     19#define AR9331_HDR_FROM_CPU		BIT(6)
     20/* AR9331_HDR_RESERVED - not used or may be version field.
     21 * According to the AR8216 doc it should 0b10. On AR9331 it is 0b11 on RX path
     22 * and should be set to 0b11 to make it work.
     23 */
     24#define AR9331_HDR_RESERVED_MASK	GENMASK(5, 4)
     25#define AR9331_HDR_PORT_NUM_MASK	GENMASK(3, 0)
     26
     27static struct sk_buff *ar9331_tag_xmit(struct sk_buff *skb,
     28				       struct net_device *dev)
     29{
     30	struct dsa_port *dp = dsa_slave_to_port(dev);
     31	__le16 *phdr;
     32	u16 hdr;
     33
     34	phdr = skb_push(skb, AR9331_HDR_LEN);
     35
     36	hdr = FIELD_PREP(AR9331_HDR_VERSION_MASK, AR9331_HDR_VERSION);
     37	hdr |= AR9331_HDR_FROM_CPU | dp->index;
     38	/* 0b10 for AR8216 and 0b11 for AR9331 */
     39	hdr |= AR9331_HDR_RESERVED_MASK;
     40
     41	phdr[0] = cpu_to_le16(hdr);
     42
     43	return skb;
     44}
     45
     46static struct sk_buff *ar9331_tag_rcv(struct sk_buff *skb,
     47				      struct net_device *ndev)
     48{
     49	u8 ver, port;
     50	u16 hdr;
     51
     52	if (unlikely(!pskb_may_pull(skb, AR9331_HDR_LEN)))
     53		return NULL;
     54
     55	hdr = le16_to_cpu(*(__le16 *)skb_mac_header(skb));
     56
     57	ver = FIELD_GET(AR9331_HDR_VERSION_MASK, hdr);
     58	if (unlikely(ver != AR9331_HDR_VERSION)) {
     59		netdev_warn_once(ndev, "%s:%i wrong header version 0x%2x\n",
     60				 __func__, __LINE__, hdr);
     61		return NULL;
     62	}
     63
     64	if (unlikely(hdr & AR9331_HDR_FROM_CPU)) {
     65		netdev_warn_once(ndev, "%s:%i packet should not be from cpu 0x%2x\n",
     66				 __func__, __LINE__, hdr);
     67		return NULL;
     68	}
     69
     70	skb_pull_rcsum(skb, AR9331_HDR_LEN);
     71
     72	/* Get source port information */
     73	port = FIELD_GET(AR9331_HDR_PORT_NUM_MASK, hdr);
     74
     75	skb->dev = dsa_master_find_slave(ndev, 0, port);
     76	if (!skb->dev)
     77		return NULL;
     78
     79	return skb;
     80}
     81
     82static const struct dsa_device_ops ar9331_netdev_ops = {
     83	.name	= "ar9331",
     84	.proto	= DSA_TAG_PROTO_AR9331,
     85	.xmit	= ar9331_tag_xmit,
     86	.rcv	= ar9331_tag_rcv,
     87	.needed_headroom = AR9331_HDR_LEN,
     88};
     89
     90MODULE_LICENSE("GPL v2");
     91MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_AR9331);
     92module_dsa_tag_driver(ar9331_netdev_ops);