cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

checksum.h (2371B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2/*
      3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
      4 *
      5 * Joern Rennecke  <joern.rennecke@embecosm.com>: Jan 2012
      6 *  -Insn Scheduling improvements to csum core routines.
      7 *      = csum_fold( ) largely derived from ARM version.
      8 *      = ip_fast_cum( ) to have module scheduling
      9 *  -gcc 4.4.x broke networking. Alias analysis needed to be primed.
     10 *   worked around by adding memory clobber to ip_fast_csum( )
     11 *
     12 * vineetg: May 2010
     13 *  -Rewrote ip_fast_cscum( ) and csum_fold( ) with fast inline asm
     14 */
     15
     16#ifndef _ASM_ARC_CHECKSUM_H
     17#define _ASM_ARC_CHECKSUM_H
     18
     19/*
     20 *	Fold a partial checksum
     21 *
     22 *  The 2 swords comprising the 32bit sum are added, any carry to 16th bit
     23 *  added back and final sword result inverted.
     24 */
     25static inline __sum16 csum_fold(__wsum s)
     26{
     27	unsigned int r = s << 16 | s >> 16;	/* ror */
     28	s = ~s;
     29	s -= r;
     30	return s >> 16;
     31}
     32
     33/*
     34 *	This is a version of ip_compute_csum() optimized for IP headers,
     35 *	which always checksum on 4 octet boundaries.
     36 */
     37static inline __sum16
     38ip_fast_csum(const void *iph, unsigned int ihl)
     39{
     40	const void *ptr = iph;
     41	unsigned int tmp, tmp2, sum;
     42
     43	__asm__(
     44	"	ld.ab  %0, [%3, 4]		\n"
     45	"	ld.ab  %2, [%3, 4]		\n"
     46	"	sub    %1, %4, 2		\n"
     47	"	lsr.f  lp_count, %1, 1		\n"
     48	"	bcc    0f			\n"
     49	"	add.f  %0, %0, %2		\n"
     50	"	ld.ab  %2, [%3, 4]		\n"
     51	"0:	lp     1f			\n"
     52	"	ld.ab  %1, [%3, 4]		\n"
     53	"	adc.f  %0, %0, %2		\n"
     54	"	ld.ab  %2, [%3, 4]		\n"
     55	"	adc.f  %0, %0, %1		\n"
     56	"1:	adc.f  %0, %0, %2		\n"
     57	"	add.cs %0,%0,1			\n"
     58	: "=&r"(sum), "=r"(tmp), "=&r"(tmp2), "+&r" (ptr)
     59	: "r"(ihl)
     60	: "cc", "lp_count", "memory");
     61
     62	return csum_fold(sum);
     63}
     64
     65/*
     66 * TCP pseudo Header is 12 bytes:
     67 * SA [4], DA [4], zeroes [1], Proto[1], TCP Seg(hdr+data) Len [2]
     68 */
     69static inline __wsum
     70csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
     71		   __u8 proto, __wsum sum)
     72{
     73	__asm__ __volatile__(
     74	"	add.f %0, %0, %1	\n"
     75	"	adc.f %0, %0, %2	\n"
     76	"	adc.f %0, %0, %3	\n"
     77	"	adc.f %0, %0, %4	\n"
     78	"	adc   %0, %0, 0		\n"
     79	: "+&r"(sum)
     80	: "r"(saddr), "r"(daddr),
     81#ifdef CONFIG_CPU_BIG_ENDIAN
     82	  "r"(len),
     83#else
     84	  "r"(len << 8),
     85#endif
     86	  "r"(htons(proto))
     87	: "cc");
     88
     89	return sum;
     90}
     91
     92#define csum_fold csum_fold
     93#define ip_fast_csum ip_fast_csum
     94#define csum_tcpudp_nofold csum_tcpudp_nofold
     95
     96#include <asm-generic/checksum.h>
     97
     98#endif /* _ASM_ARC_CHECKSUM_H */