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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  */
46 extern __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  */
54 static inline
ip_fast_csum(const void * iph,unsigned int ihl)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", "memory"
79 	    );
80 
81 	return (__force __sum16)~sum;
82 }
83 
84 /*
85  *	Fold a partial checksum
86  */
csum_fold(__wsum sum)87 static 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  */
107 static inline __wsum
csum_tcpudp_nofold(__be32 saddr,__be32 daddr,unsigned short len,unsigned short proto,__wsum sum)108 csum_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 
122 static inline __sum16
csum_tcpudp_magic(__be32 saddr,__be32 daddr,unsigned short len,unsigned short proto,__wsum sum)123 csum_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  */
133 extern __sum16 ip_compute_csum(const void *buff, int len);
134 
135 #define _HAVE_ARCH_IPV6_CSUM
136 static inline __sum16
csum_ipv6_magic(const struct in6_addr * saddr,const struct in6_addr * daddr,__u32 len,unsigned short proto,__wsum sum)137 csum_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