1/* checksum.h: FRV checksumming
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#ifndef _ASM_CHECKSUM_H
13#define _ASM_CHECKSUM_H
14
15#include <linux/in6.h>
16
17/*
18 * computes the checksum of a memory block at buff, length len,
19 * and adds in "sum" (32-bit)
20 *
21 * returns a 32-bit number suitable for feeding into itself
22 * or csum_tcpudp_magic
23 *
24 * this function must be called with even lengths, except
25 * for the last fragment, which may be odd
26 *
27 * it's best to have buff aligned on a 32-bit boundary
28 */
29__wsum csum_partial(const void *buff, int len, __wsum sum);
30
31/*
32 * the same as csum_partial, but copies from src while it
33 * checksums
34 *
35 * here even more important to align src and dst on a 32-bit (or even
36 * better 64-bit) boundary
37 */
38__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
39
40/*
41 * the same as csum_partial_copy, but copies from user space.
42 *
43 * here even more important to align src and dst on a 32-bit (or even
44 * better 64-bit) boundary
45 */
46extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
47						int len, __wsum sum, int *csum_err);
48
49/*
50 *	This is a version of ip_compute_csum() optimized for IP headers,
51 *	which always checksum on 4 octet boundaries.
52 *
53 */
54static inline
55__sum16 ip_fast_csum(const void *iph, unsigned int ihl)
56{
57	unsigned int tmp, inc, sum = 0;
58
59	asm("	addcc		gr0,gr0,gr0,icc0\n" /* clear icc0.C */
60	    "	subi		%1,#4,%1	\n"
61	    "0:					\n"
62	    "	ldu.p		@(%1,%3),%4	\n"
63	    "	subicc		%2,#1,%2,icc1	\n"
64	    "	addxcc.p	%4,%0,%0,icc0	\n"
65	    "	bhi		icc1,#2,0b	\n"
66
67	    /* fold the 33-bit result into 16-bits */
68	    "	addxcc		gr0,%0,%0,icc0	\n"
69	    "	srli		%0,#16,%1	\n"
70	    "	sethi		#0,%0		\n"
71	    "	add		%1,%0,%0	\n"
72	    "	srli		%0,#16,%1	\n"
73	    "	add		%1,%0,%0	\n"
74
75	    : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (inc), "=&r"(tmp)
76	    : "0" (sum), "1" (iph), "2" (ihl), "3" (4),
77	    "m"(*(volatile struct { int _[100]; } *)iph)
78	    : "icc0", "icc1"
79	    );
80
81	return (__force __sum16)~sum;
82}
83
84/*
85 *	Fold a partial checksum
86 */
87static inline __sum16 csum_fold(__wsum sum)
88{
89	unsigned int tmp;
90
91	asm("	srli		%0,#16,%1	\n"
92	    "	sethi		#0,%0		\n"
93	    "	add		%1,%0,%0	\n"
94	    "	srli		%0,#16,%1	\n"
95	    "	add		%1,%0,%0	\n"
96	    : "=r"(sum), "=&r"(tmp)
97	    : "0"(sum)
98	    );
99
100	return (__force __sum16)~sum;
101}
102
103/*
104 * computes the checksum of the TCP/UDP pseudo-header
105 * returns a 16-bit checksum, already complemented
106 */
107static inline __wsum
108csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
109		  unsigned short proto, __wsum sum)
110{
111	asm("	addcc		%1,%0,%0,icc0	\n"
112	    "	addxcc		%2,%0,%0,icc0	\n"
113	    "	addxcc		%3,%0,%0,icc0	\n"
114	    "	addxcc		gr0,%0,%0,icc0	\n"
115	    : "=r" (sum)
116	    : "r" (daddr), "r" (saddr), "r" (len + proto), "0"(sum)
117	    : "icc0"
118	    );
119	return sum;
120}
121
122static inline __sum16
123csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
124		  unsigned short proto, __wsum sum)
125{
126	return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
127}
128
129/*
130 * this routine is used for miscellaneous IP-like checksums, mainly
131 * in icmp.c
132 */
133extern __sum16 ip_compute_csum(const void *buff, int len);
134
135#define _HAVE_ARCH_IPV6_CSUM
136static inline __sum16
137csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
138		__u32 len, unsigned short proto, __wsum sum)
139{
140	unsigned long tmp, tmp2;
141
142	asm("	addcc		%2,%0,%0,icc0	\n"
143
144	    /* add up the source addr */
145	    "	ldi		@(%3,0),%1	\n"
146	    "	addxcc		%1,%0,%0,icc0	\n"
147	    "	ldi		@(%3,4),%2	\n"
148	    "	addxcc		%2,%0,%0,icc0	\n"
149	    "	ldi		@(%3,8),%1	\n"
150	    "	addxcc		%1,%0,%0,icc0	\n"
151	    "	ldi		@(%3,12),%2	\n"
152	    "	addxcc		%2,%0,%0,icc0	\n"
153
154	    /* add up the dest addr */
155	    "	ldi		@(%4,0),%1	\n"
156	    "	addxcc		%1,%0,%0,icc0	\n"
157	    "	ldi		@(%4,4),%2	\n"
158	    "	addxcc		%2,%0,%0,icc0	\n"
159	    "	ldi		@(%4,8),%1	\n"
160	    "	addxcc		%1,%0,%0,icc0	\n"
161	    "	ldi		@(%4,12),%2	\n"
162	    "	addxcc		%2,%0,%0,icc0	\n"
163
164	    /* fold the 33-bit result into 16-bits */
165	    "	addxcc		gr0,%0,%0,icc0	\n"
166	    "	srli		%0,#16,%1	\n"
167	    "	sethi		#0,%0		\n"
168	    "	add		%1,%0,%0	\n"
169	    "	srli		%0,#16,%1	\n"
170	    "	add		%1,%0,%0	\n"
171
172	    : "=r" (sum), "=&r" (tmp), "=r" (tmp2)
173	    : "r" (saddr), "r" (daddr), "0" (sum), "2" (len + proto)
174	    : "icc0"
175	    );
176
177	return (__force __sum16)~sum;
178}
179
180#endif /* _ASM_CHECKSUM_H */
181