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Linux/arch/xtensa/include/asm/checksum.h

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  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 <variant/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,
 41                                             int len, __wsum sum,
 42                                             int *src_err_ptr, int *dst_err_ptr);
 43 
 44 /*
 45  *      Note: when you get a NULL pointer exception here this means someone
 46  *      passed in an incorrect kernel address to one of these functions.
 47  *
 48  *      If you use these functions directly please don't forget the access_ok().
 49  */
 50 static inline
 51 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 52                                         int len, __wsum sum)
 53 {
 54         return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
 55 }
 56 
 57 static inline
 58 __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
 59                                    int len, __wsum sum, int *err_ptr)
 60 {
 61         return csum_partial_copy_generic((__force const void *)src, dst,
 62                                         len, sum, err_ptr, NULL);
 63 }
 64 
 65 /*
 66  *      Fold a partial checksum
 67  */
 68 
 69 static __inline__ __sum16 csum_fold(__wsum sum)
 70 {
 71         unsigned int __dummy;
 72         __asm__("extui  %1, %0, 16, 16\n\t"
 73                 "extui  %0 ,%0, 0, 16\n\t"
 74                 "add    %0, %0, %1\n\t"
 75                 "slli   %1, %0, 16\n\t"
 76                 "add    %0, %0, %1\n\t"
 77                 "extui  %0, %0, 16, 16\n\t"
 78                 "neg    %0, %0\n\t"
 79                 "addi   %0, %0, -1\n\t"
 80                 "extui  %0, %0, 0, 16\n\t"
 81                 : "=r" (sum), "=&r" (__dummy)
 82                 : "" (sum));
 83         return (__force __sum16)sum;
 84 }
 85 
 86 /*
 87  *      This is a version of ip_compute_csum() optimized for IP headers,
 88  *      which always checksum on 4 octet boundaries.
 89  */
 90 static __inline__ __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
 91 {
 92         unsigned int sum, tmp, endaddr;
 93 
 94         __asm__ __volatile__(
 95                 "sub            %0, %0, %0\n\t"
 96 #if XCHAL_HAVE_LOOPS
 97                 "loopgtz        %2, 2f\n\t"
 98 #else
 99                 "beqz           %2, 2f\n\t"
100                 "slli           %4, %2, 2\n\t"
101                 "add            %4, %4, %1\n\t"
102                 "0:\t"
103 #endif
104                 "l32i           %3, %1, 0\n\t"
105                 "add            %0, %0, %3\n\t"
106                 "bgeu           %0, %3, 1f\n\t"
107                 "addi           %0, %0, 1\n\t"
108                 "1:\t"
109                 "addi           %1, %1, 4\n\t"
110 #if !XCHAL_HAVE_LOOPS
111                 "blt            %1, %4, 0b\n\t"
112 #endif
113                 "2:\t"
114         /* Since the input registers which are loaded with iph and ihl
115            are modified, we must also specify them as outputs, or gcc
116            will assume they contain their original values. */
117                 : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (tmp),
118                   "=&r" (endaddr)
119                 : "1" (iph), "2" (ihl)
120                 : "memory");
121 
122         return  csum_fold(sum);
123 }
124 
125 static __inline__ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
126                                             __u32 len, __u8 proto,
127                                             __wsum sum)
128 {
129 
130 #ifdef __XTENSA_EL__
131         unsigned long len_proto = (len + proto) << 8;
132 #elif defined(__XTENSA_EB__)
133         unsigned long len_proto = len + proto;
134 #else
135 # error processor byte order undefined!
136 #endif
137         __asm__("add    %0, %0, %1\n\t"
138                 "bgeu   %0, %1, 1f\n\t"
139                 "addi   %0, %0, 1\n\t"
140                 "1:\t"
141                 "add    %0, %0, %2\n\t"
142                 "bgeu   %0, %2, 1f\n\t"
143                 "addi   %0, %0, 1\n\t"
144                 "1:\t"
145                 "add    %0, %0, %3\n\t"
146                 "bgeu   %0, %3, 1f\n\t"
147                 "addi   %0, %0, 1\n\t"
148                 "1:\t"
149                 : "=r" (sum), "=r" (len_proto)
150                 : "r" (daddr), "r" (saddr), "1" (len_proto), "" (sum));
151         return sum;
152 }
153 
154 /*
155  * computes the checksum of the TCP/UDP pseudo-header
156  * returns a 16-bit checksum, already complemented
157  */
158 static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
159                                             __u32 len, __u8 proto,
160                                             __wsum sum)
161 {
162         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
163 }
164 
165 /*
166  * this routine is used for miscellaneous IP-like checksums, mainly
167  * in icmp.c
168  */
169 
170 static __inline__ __sum16 ip_compute_csum(const void *buff, int len)
171 {
172         return csum_fold (csum_partial(buff, len, 0));
173 }
174 
175 #define _HAVE_ARCH_IPV6_CSUM
176 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
177                                           const struct in6_addr *daddr,
178                                           __u32 len, __u8 proto,
179                                           __wsum sum)
180 {
181         unsigned int __dummy;
182         __asm__("l32i   %1, %2, 0\n\t"
183                 "add    %0, %0, %1\n\t"
184                 "bgeu   %0, %1, 1f\n\t"
185                 "addi   %0, %0, 1\n\t"
186                 "1:\t"
187                 "l32i   %1, %2, 4\n\t"
188                 "add    %0, %0, %1\n\t"
189                 "bgeu   %0, %1, 1f\n\t"
190                 "addi   %0, %0, 1\n\t"
191                 "1:\t"
192                 "l32i   %1, %2, 8\n\t"
193                 "add    %0, %0, %1\n\t"
194                 "bgeu   %0, %1, 1f\n\t"
195                 "addi   %0, %0, 1\n\t"
196                 "1:\t"
197                 "l32i   %1, %2, 12\n\t"
198                 "add    %0, %0, %1\n\t"
199                 "bgeu   %0, %1, 1f\n\t"
200                 "addi   %0, %0, 1\n\t"
201                 "1:\t"
202                 "l32i   %1, %3, 0\n\t"
203                 "add    %0, %0, %1\n\t"
204                 "bgeu   %0, %1, 1f\n\t"
205                 "addi   %0, %0, 1\n\t"
206                 "1:\t"
207                 "l32i   %1, %3, 4\n\t"
208                 "add    %0, %0, %1\n\t"
209                 "bgeu   %0, %1, 1f\n\t"
210                 "addi   %0, %0, 1\n\t"
211                 "1:\t"
212                 "l32i   %1, %3, 8\n\t"
213                 "add    %0, %0, %1\n\t"
214                 "bgeu   %0, %1, 1f\n\t"
215                 "addi   %0, %0, 1\n\t"
216                 "1:\t"
217                 "l32i   %1, %3, 12\n\t"
218                 "add    %0, %0, %1\n\t"
219                 "bgeu   %0, %1, 1f\n\t"
220                 "addi   %0, %0, 1\n\t"
221                 "1:\t"
222                 "add    %0, %0, %4\n\t"
223                 "bgeu   %0, %4, 1f\n\t"
224                 "addi   %0, %0, 1\n\t"
225                 "1:\t"
226                 "add    %0, %0, %5\n\t"
227                 "bgeu   %0, %5, 1f\n\t"
228                 "addi   %0, %0, 1\n\t"
229                 "1:\t"
230                 : "=r" (sum), "=&r" (__dummy)
231                 : "r" (saddr), "r" (daddr),
232                   "r" (htonl(len)), "r" (htonl(proto)), "" (sum)
233                 : "memory");
234 
235         return csum_fold(sum);
236 }
237 
238 /*
239  *      Copy and checksum to user
240  */
241 #define HAVE_CSUM_COPY_USER
242 static __inline__ __wsum csum_and_copy_to_user(const void *src,
243                                                void __user *dst, int len,
244                                                __wsum sum, int *err_ptr)
245 {
246         if (access_ok(VERIFY_WRITE, dst, len))
247                 return csum_partial_copy_generic(src,dst,len,sum,NULL,err_ptr);
248 
249         if (len)
250                 *err_ptr = -EFAULT;
251 
252         return (__force __wsum)-1; /* invalid checksum */
253 }
254 #endif
255 

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