linux/arch/arm64/include/asm/checksum.h
Robin Murphy e9c7ddbf8b arm64: csum: Optimise IPv6 header checksum
Throwing our __uint128_t idioms at csum_ipv6_magic() makes it
about 1.3x-2x faster across a range of microarchitecture/compiler
combinations. Not much in absolute terms, but every little helps.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-03-09 18:08:25 +00:00

49 lines
1.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2016 ARM Ltd.
*/
#ifndef __ASM_CHECKSUM_H
#define __ASM_CHECKSUM_H
#include <linux/in6.h>
#define _HAVE_ARCH_IPV6_CSUM
__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__u32 len, __u8 proto, __wsum sum);
static inline __sum16 csum_fold(__wsum csum)
{
u32 sum = (__force u32)csum;
sum += (sum >> 16) | (sum << 16);
return ~(__force __sum16)(sum >> 16);
}
#define csum_fold csum_fold
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
__uint128_t tmp;
u64 sum;
tmp = *(const __uint128_t *)iph;
iph += 16;
ihl -= 4;
tmp += ((tmp >> 64) | (tmp << 64));
sum = tmp >> 64;
do {
sum += *(const u32 *)iph;
iph += 4;
} while (--ihl);
sum += ((sum >> 32) | (sum << 32));
return csum_fold((__force u32)(sum >> 32));
}
#define ip_fast_csum ip_fast_csum
extern unsigned int do_csum(const unsigned char *buff, int len);
#define do_csum do_csum
#include <asm-generic/checksum.h>
#endif /* __ASM_CHECKSUM_H */