mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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1f87e235e6
Linus mentioned we could try to perform long word operations, even on potentially unaligned addresses, on x86 at least. David mentioned the HAVE_EFFICIENT_UNALIGNED_ACCESS test to handle this on all arches that have efficient unailgned accesses. I tried this idea and got nice assembly on 32 bits: 158: 33 82 38 01 00 00 xor 0x138(%edx),%eax 15e: 33 8a 34 01 00 00 xor 0x134(%edx),%ecx 164: c1 e0 10 shl $0x10,%eax 167: 09 c1 or %eax,%ecx 169: 74 0b je 176 <eth_type_trans+0x87> And very nice assembly on 64 bits of course (one xor, one shl) Nice oprofile improvement in eth_type_trans(), 0.17 % instead of 0.41 %, expected since we remove 8 instructions on a fast path. This patch implements a compare_ether_addr_64bits() function, that uses the CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS ifdef to efficiently perform the 6 bytes comparison on all capable arches. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
188 lines
5.9 KiB
C
188 lines
5.9 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. NET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Definitions for the Ethernet handlers.
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*
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* Version: @(#)eth.h 1.0.4 05/13/93
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*
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* Authors: Ross Biro
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* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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*
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* Relocated to include/linux where it belongs by Alan Cox
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* <gw4pts@gw4pts.ampr.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* WARNING: This move may well be temporary. This file will get merged with others RSN.
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*
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*/
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#ifndef _LINUX_ETHERDEVICE_H
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#define _LINUX_ETHERDEVICE_H
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#include <linux/if_ether.h>
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#include <linux/netdevice.h>
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#include <linux/random.h>
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#include <asm/unaligned.h>
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#ifdef __KERNEL__
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extern __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
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extern const struct header_ops eth_header_ops;
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extern int eth_header(struct sk_buff *skb, struct net_device *dev,
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unsigned short type,
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const void *daddr, const void *saddr, unsigned len);
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extern int eth_rebuild_header(struct sk_buff *skb);
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extern int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
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extern int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh);
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extern void eth_header_cache_update(struct hh_cache *hh,
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const struct net_device *dev,
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const unsigned char *haddr);
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extern int eth_mac_addr(struct net_device *dev, void *p);
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extern int eth_change_mtu(struct net_device *dev, int new_mtu);
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extern int eth_validate_addr(struct net_device *dev);
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extern struct net_device *alloc_etherdev_mq(int sizeof_priv, unsigned int queue_count);
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#define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)
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/**
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* is_zero_ether_addr - Determine if give Ethernet address is all zeros.
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* @addr: Pointer to a six-byte array containing the Ethernet address
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*
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* Return true if the address is all zeroes.
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*/
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static inline int is_zero_ether_addr(const u8 *addr)
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{
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return !(addr[0] | addr[1] | addr[2] | addr[3] | addr[4] | addr[5]);
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}
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/**
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* is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
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* @addr: Pointer to a six-byte array containing the Ethernet address
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*
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* Return true if the address is a multicast address.
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* By definition the broadcast address is also a multicast address.
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*/
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static inline int is_multicast_ether_addr(const u8 *addr)
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{
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return (0x01 & addr[0]);
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}
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/**
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* is_local_ether_addr - Determine if the Ethernet address is locally-assigned one (IEEE 802).
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* @addr: Pointer to a six-byte array containing the Ethernet address
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*
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* Return true if the address is a local address.
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*/
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static inline int is_local_ether_addr(const u8 *addr)
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{
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return (0x02 & addr[0]);
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}
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/**
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* is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
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* @addr: Pointer to a six-byte array containing the Ethernet address
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*
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* Return true if the address is the broadcast address.
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*/
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static inline int is_broadcast_ether_addr(const u8 *addr)
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{
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return (addr[0] & addr[1] & addr[2] & addr[3] & addr[4] & addr[5]) == 0xff;
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}
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/**
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* is_valid_ether_addr - Determine if the given Ethernet address is valid
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* @addr: Pointer to a six-byte array containing the Ethernet address
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*
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* Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
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* a multicast address, and is not FF:FF:FF:FF:FF:FF.
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*
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* Return true if the address is valid.
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*/
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static inline int is_valid_ether_addr(const u8 *addr)
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{
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/* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
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* explicitly check for it here. */
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return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
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}
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/**
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* random_ether_addr - Generate software assigned random Ethernet address
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* @addr: Pointer to a six-byte array containing the Ethernet address
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*
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* Generate a random Ethernet address (MAC) that is not multicast
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* and has the local assigned bit set.
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*/
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static inline void random_ether_addr(u8 *addr)
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{
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get_random_bytes (addr, ETH_ALEN);
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addr [0] &= 0xfe; /* clear multicast bit */
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addr [0] |= 0x02; /* set local assignment bit (IEEE802) */
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}
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/**
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* compare_ether_addr - Compare two Ethernet addresses
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* @addr1: Pointer to a six-byte array containing the Ethernet address
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* @addr2: Pointer other six-byte array containing the Ethernet address
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*
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* Compare two ethernet addresses, returns 0 if equal
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*/
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static inline unsigned compare_ether_addr(const u8 *addr1, const u8 *addr2)
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{
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const u16 *a = (const u16 *) addr1;
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const u16 *b = (const u16 *) addr2;
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BUILD_BUG_ON(ETH_ALEN != 6);
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return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0;
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}
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static inline unsigned long zap_last_2bytes(unsigned long value)
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{
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#ifdef __BIG_ENDIAN
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return value >> 16;
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#else
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return value << 16;
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#endif
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}
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/**
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* compare_ether_addr_64bits - Compare two Ethernet addresses
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* @addr1: Pointer to an array of 8 bytes
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* @addr2: Pointer to an other array of 8 bytes
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*
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* Compare two ethernet addresses, returns 0 if equal.
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* Same result than "memcmp(addr1, addr2, ETH_ALEN)" but without conditional
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* branches, and possibly long word memory accesses on CPU allowing cheap
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* unaligned memory reads.
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* arrays = { byte1, byte2, byte3, byte4, byte6, byte7, pad1, pad2}
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*
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* Please note that alignment of addr1 & addr2 is only guaranted to be 16 bits.
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*/
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static inline unsigned compare_ether_addr_64bits(const u8 addr1[6+2],
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const u8 addr2[6+2])
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{
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#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
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unsigned long fold = ((*(unsigned long *)addr1) ^
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(*(unsigned long *)addr2));
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if (sizeof(fold) == 8)
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return zap_last_2bytes(fold) != 0;
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fold |= zap_last_2bytes((*(unsigned long *)(addr1 + 4)) ^
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(*(unsigned long *)(addr2 + 4)));
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return fold != 0;
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#else
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return compare_ether_addr(addr1, addr2);
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#endif
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}
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#endif /* __KERNEL__ */
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#endif /* _LINUX_ETHERDEVICE_H */
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