1 /*
2 * include/asm-xtensa/checksum.h
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2001 - 2005 Tensilica Inc.
9 */
10
11 #ifndef _XTENSA_CHECKSUM_H
12 #define _XTENSA_CHECKSUM_H
13
14 #include <linux/in6.h>
15 #include <linux/uaccess.h>
16 #include <asm/core.h>
17
18 /*
19 * computes the checksum of a memory block at buff, length len,
20 * and adds in "sum" (32-bit)
21 *
22 * returns a 32-bit number suitable for feeding into itself
23 * or csum_tcpudp_magic
24 *
25 * this function must be called with even lengths, except
26 * for the last fragment, which may be odd
27 *
28 * it's best to have buff aligned on a 32-bit boundary
29 */
30 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
31
32 /*
33 * the same as csum_partial, but copies from src while it
34 * checksums, and handles user-space pointer exceptions correctly, when needed.
35 *
36 * here even more important to align src and dst on a 32-bit (or even
37 * better 64-bit) boundary
38 */
39
40 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
41
42 #define _HAVE_ARCH_CSUM_AND_COPY
43 /*
44 * Note: when you get a NULL pointer exception here this means someone
45 * passed in an incorrect kernel address to one of these functions.
46 */
47 static inline
48 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
49 {
50 return csum_partial_copy_generic(src, dst, len);
51 }
52
53 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
54 static inline
55 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
56 int len)
57 {
58 if (!access_ok(src, len))
59 return 0;
60 return csum_partial_copy_generic((__force const void *)src, dst, len);
61 }
62
63 /*
64 * Fold a partial checksum
65 */
66
67 static __inline__ __sum16 csum_fold(__wsum sum)
68 {
69 unsigned int __dummy;
70 __asm__("extui %1, %0, 16, 16\n\t"
71 "extui %0 ,%0, 0, 16\n\t"
72 "add %0, %0, %1\n\t"
73 "slli %1, %0, 16\n\t"
74 "add %0, %0, %1\n\t"
75 "extui %0, %0, 16, 16\n\t"
76 "neg %0, %0\n\t"
77 "addi %0, %0, -1\n\t"
78 "extui %0, %0, 0, 16\n\t"
79 : "=r" (sum), "=&r" (__dummy)
80 : "" (sum));
81 return (__force __sum16)sum;
82 }
83
84 /*
85 * This is a version of ip_compute_csum() optimized for IP headers,
86 * which always checksum on 4 octet boundaries.
87 */
88 static __inline__ __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
89 {
90 unsigned int sum, tmp, endaddr;
91
92 __asm__ __volatile__(
93 "sub %0, %0, %0\n\t"
94 #if XCHAL_HAVE_LOOPS
95 "loopgtz %2, 2f\n\t"
96 #else
97 "beqz %2, 2f\n\t"
98 "slli %4, %2, 2\n\t"
99 "add %4, %4, %1\n\t"
100 "0:\t"
101 #endif
102 "l32i %3, %1, 0\n\t"
103 "add %0, %0, %3\n\t"
104 "bgeu %0, %3, 1f\n\t"
105 "addi %0, %0, 1\n\t"
106 "1:\t"
107 "addi %1, %1, 4\n\t"
108 #if !XCHAL_HAVE_LOOPS
109 "blt %1, %4, 0b\n\t"
110 #endif
111 "2:\t"
112 /* Since the input registers which are loaded with iph and ihl
113 are modified, we must also specify them as outputs, or gcc
114 will assume they contain their original values. */
115 : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (tmp),
116 "=&r" (endaddr)
117 : "1" (iph), "2" (ihl)
118 : "memory");
119
120 return csum_fold(sum);
121 }
122
123 static __inline__ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
124 __u32 len, __u8 proto,
125 __wsum sum)
126 {
127
128 #ifdef __XTENSA_EL__
129 unsigned long len_proto = (len + proto) << 8;
130 #elif defined(__XTENSA_EB__)
131 unsigned long len_proto = len + proto;
132 #else
133 # error processor byte order undefined!
134 #endif
135 __asm__("add %0, %0, %1\n\t"
136 "bgeu %0, %1, 1f\n\t"
137 "addi %0, %0, 1\n\t"
138 "1:\t"
139 "add %0, %0, %2\n\t"
140 "bgeu %0, %2, 1f\n\t"
141 "addi %0, %0, 1\n\t"
142 "1:\t"
143 "add %0, %0, %3\n\t"
144 "bgeu %0, %3, 1f\n\t"
145 "addi %0, %0, 1\n\t"
146 "1:\t"
147 : "=r" (sum), "=r" (len_proto)
148 : "r" (daddr), "r" (saddr), "1" (len_proto), "" (sum));
149 return sum;
150 }
151
152 /*
153 * computes the checksum of the TCP/UDP pseudo-header
154 * returns a 16-bit checksum, already complemented
155 */
156 static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
157 __u32 len, __u8 proto,
158 __wsum sum)
159 {
160 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
161 }
162
163 /*
164 * this routine is used for miscellaneous IP-like checksums, mainly
165 * in icmp.c
166 */
167
168 static __inline__ __sum16 ip_compute_csum(const void *buff, int len)
169 {
170 return csum_fold (csum_partial(buff, len, 0));
171 }
172
173 #define _HAVE_ARCH_IPV6_CSUM
174 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
175 const struct in6_addr *daddr,
176 __u32 len, __u8 proto,
177 __wsum sum)
178 {
179 unsigned int __dummy;
180 __asm__("l32i %1, %2, 0\n\t"
181 "add %0, %0, %1\n\t"
182 "bgeu %0, %1, 1f\n\t"
183 "addi %0, %0, 1\n\t"
184 "1:\t"
185 "l32i %1, %2, 4\n\t"
186 "add %0, %0, %1\n\t"
187 "bgeu %0, %1, 1f\n\t"
188 "addi %0, %0, 1\n\t"
189 "1:\t"
190 "l32i %1, %2, 8\n\t"
191 "add %0, %0, %1\n\t"
192 "bgeu %0, %1, 1f\n\t"
193 "addi %0, %0, 1\n\t"
194 "1:\t"
195 "l32i %1, %2, 12\n\t"
196 "add %0, %0, %1\n\t"
197 "bgeu %0, %1, 1f\n\t"
198 "addi %0, %0, 1\n\t"
199 "1:\t"
200 "l32i %1, %3, 0\n\t"
201 "add %0, %0, %1\n\t"
202 "bgeu %0, %1, 1f\n\t"
203 "addi %0, %0, 1\n\t"
204 "1:\t"
205 "l32i %1, %3, 4\n\t"
206 "add %0, %0, %1\n\t"
207 "bgeu %0, %1, 1f\n\t"
208 "addi %0, %0, 1\n\t"
209 "1:\t"
210 "l32i %1, %3, 8\n\t"
211 "add %0, %0, %1\n\t"
212 "bgeu %0, %1, 1f\n\t"
213 "addi %0, %0, 1\n\t"
214 "1:\t"
215 "l32i %1, %3, 12\n\t"
216 "add %0, %0, %1\n\t"
217 "bgeu %0, %1, 1f\n\t"
218 "addi %0, %0, 1\n\t"
219 "1:\t"
220 "add %0, %0, %4\n\t"
221 "bgeu %0, %4, 1f\n\t"
222 "addi %0, %0, 1\n\t"
223 "1:\t"
224 "add %0, %0, %5\n\t"
225 "bgeu %0, %5, 1f\n\t"
226 "addi %0, %0, 1\n\t"
227 "1:\t"
228 : "=r" (sum), "=&r" (__dummy)
229 : "r" (saddr), "r" (daddr),
230 "r" (htonl(len)), "r" (htonl(proto)), "" (sum)
231 : "memory");
232
233 return csum_fold(sum);
234 }
235
236 /*
237 * Copy and checksum to user
238 */
239 #define HAVE_CSUM_COPY_USER
240 static __inline__ __wsum csum_and_copy_to_user(const void *src,
241 void __user *dst, int len)
242 {
243 if (!access_ok(dst, len))
244 return 0;
245 return csum_partial_copy_generic(src, (__force void *)dst, len);
246 }
247 #endif
248
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