1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_SH_CHECKSUM_H
3 #define __ASM_SH_CHECKSUM_H
4
5 /*
6 * Copyright (C) 1999 by Kaz Kojima & Niibe Yutaka
7 */
8
9 #include <linux/in6.h>
10 #include <linux/uaccess.h>
11
12 /*
13 * computes the checksum of a memory block at buff, length len,
14 * and adds in "sum" (32-bit)
15 *
16 * returns a 32-bit number suitable for feeding into itself
17 * or csum_tcpudp_magic
18 *
19 * this function must be called with even lengths, except
20 * for the last fragment, which may be odd
21 *
22 * it's best to have buff aligned on a 32-bit boundary
23 */
24 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
25
26 /*
27 * the same as csum_partial, but copies from src while it
28 * checksums, and handles user-space pointer exceptions correctly, when needed.
29 *
30 * here even more important to align src and dst on a 32-bit (or even
31 * better 64-bit) boundary
32 */
33
34 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
35
36 #define _HAVE_ARCH_CSUM_AND_COPY
37 /*
38 * Note: when you get a NULL pointer exception here this means someone
39 * passed in an incorrect kernel address to one of these functions.
40 *
41 * If you use these functions directly please don't forget the
42 * access_ok().
43 */
44 static inline
45 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
46 {
47 return csum_partial_copy_generic(src, dst, len);
48 }
49
50 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
51 static inline
52 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
53 {
54 if (!access_ok(src, len))
55 return 0;
56 return csum_partial_copy_generic((__force const void *)src, dst, len);
57 }
58
59 /*
60 * Fold a partial checksum
61 */
62
63 static inline __sum16 csum_fold(__wsum sum)
64 {
65 unsigned int __dummy;
66 __asm__("swap.w %0, %1\n\t"
67 "extu.w %0, %0\n\t"
68 "extu.w %1, %1\n\t"
69 "add %1, %0\n\t"
70 "swap.w %0, %1\n\t"
71 "add %1, %0\n\t"
72 "not %0, %0\n\t"
73 : "=r" (sum), "=&r" (__dummy)
74 : "" (sum)
75 : "t");
76 return (__force __sum16)sum;
77 }
78
79 /*
80 * This is a version of ip_compute_csum() optimized for IP headers,
81 * which always checksum on 4 octet boundaries.
82 *
83 * i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
84 * for linux by * Arnt Gulbrandsen.
85 */
86 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
87 {
88 __wsum sum;
89 unsigned int __dummy0, __dummy1;
90
91 __asm__ __volatile__(
92 "mov.l @%1+, %0\n\t"
93 "mov.l @%1+, %3\n\t"
94 "add #-2, %2\n\t"
95 "clrt\n\t"
96 "1:\t"
97 "addc %3, %0\n\t"
98 "movt %4\n\t"
99 "mov.l @%1+, %3\n\t"
100 "dt %2\n\t"
101 "bf/s 1b\n\t"
102 " cmp/eq #1, %4\n\t"
103 "addc %3, %0\n\t"
104 "addc %2, %0" /* Here %2 is 0, add carry-bit */
105 /* Since the input registers which are loaded with iph and ihl
106 are modified, we must also specify them as outputs, or gcc
107 will assume they contain their original values. */
108 : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
109 : "1" (iph), "2" (ihl)
110 : "t", "memory");
111
112 return csum_fold(sum);
113 }
114
115 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
116 __u32 len, __u8 proto,
117 __wsum sum)
118 {
119 #ifdef __LITTLE_ENDIAN__
120 unsigned long len_proto = (proto + len) << 8;
121 #else
122 unsigned long len_proto = proto + len;
123 #endif
124 __asm__("clrt\n\t"
125 "addc %0, %1\n\t"
126 "addc %2, %1\n\t"
127 "addc %3, %1\n\t"
128 "movt %0\n\t"
129 "add %1, %0"
130 : "=r" (sum), "=r" (len_proto)
131 : "r" (daddr), "r" (saddr), "1" (len_proto), "" (sum)
132 : "t");
133
134 return sum;
135 }
136
137 /*
138 * computes the checksum of the TCP/UDP pseudo-header
139 * returns a 16-bit checksum, already complemented
140 */
141 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
142 __u32 len, __u8 proto,
143 __wsum sum)
144 {
145 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
146 }
147
148 /*
149 * this routine is used for miscellaneous IP-like checksums, mainly
150 * in icmp.c
151 */
152 static inline __sum16 ip_compute_csum(const void *buff, int len)
153 {
154 return csum_fold(csum_partial(buff, len, 0));
155 }
156
157 #define _HAVE_ARCH_IPV6_CSUM
158 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
159 const struct in6_addr *daddr,
160 __u32 len, __u8 proto, __wsum sum)
161 {
162 unsigned int __dummy;
163 __asm__("clrt\n\t"
164 "mov.l @(0,%2), %1\n\t"
165 "addc %1, %0\n\t"
166 "mov.l @(4,%2), %1\n\t"
167 "addc %1, %0\n\t"
168 "mov.l @(8,%2), %1\n\t"
169 "addc %1, %0\n\t"
170 "mov.l @(12,%2), %1\n\t"
171 "addc %1, %0\n\t"
172 "mov.l @(0,%3), %1\n\t"
173 "addc %1, %0\n\t"
174 "mov.l @(4,%3), %1\n\t"
175 "addc %1, %0\n\t"
176 "mov.l @(8,%3), %1\n\t"
177 "addc %1, %0\n\t"
178 "mov.l @(12,%3), %1\n\t"
179 "addc %1, %0\n\t"
180 "addc %4, %0\n\t"
181 "addc %5, %0\n\t"
182 "movt %1\n\t"
183 "add %1, %0\n"
184 : "=r" (sum), "=&r" (__dummy)
185 : "r" (saddr), "r" (daddr),
186 "r" (htonl(len)), "r" (htonl(proto)), "" (sum)
187 : "t");
188
189 return csum_fold(sum);
190 }
191
192 /*
193 * Copy and checksum to user
194 */
195 #define HAVE_CSUM_COPY_USER
196 static inline __wsum csum_and_copy_to_user(const void *src,
197 void __user *dst,
198 int len)
199 {
200 if (!access_ok(dst, len))
201 return 0;
202 return csum_partial_copy_generic(src, (__force void *)dst, len);
203 }
204 #endif /* __ASM_SH_CHECKSUM_H */
205
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