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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 <asm/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                                                    unsigned short len,
127                                                    unsigned short proto,
128                                                    __wsum sum)
129 {
130 
131 #ifdef __XTENSA_EL__
132         unsigned long len_proto = (len + proto) << 8;
133 #elif defined(__XTENSA_EB__)
134         unsigned long len_proto = len + proto;
135 #else
136 # error processor byte order undefined!
137 #endif
138         __asm__("add    %0, %0, %1\n\t"
139                 "bgeu   %0, %1, 1f\n\t"
140                 "addi   %0, %0, 1\n\t"
141                 "1:\t"
142                 "add    %0, %0, %2\n\t"
143                 "bgeu   %0, %2, 1f\n\t"
144                 "addi   %0, %0, 1\n\t"
145                 "1:\t"
146                 "add    %0, %0, %3\n\t"
147                 "bgeu   %0, %3, 1f\n\t"
148                 "addi   %0, %0, 1\n\t"
149                 "1:\t"
150                 : "=r" (sum), "=r" (len_proto)
151                 : "r" (daddr), "r" (saddr), "1" (len_proto), "" (sum));
152         return sum;
153 }
154 
155 /*
156  * computes the checksum of the TCP/UDP pseudo-header
157  * returns a 16-bit checksum, already complemented
158  */
159 static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
160                                                        unsigned short len,
161                                                        unsigned short proto,
162                                                        __wsum sum)
163 {
164         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
165 }
166 
167 /*
168  * this routine is used for miscellaneous IP-like checksums, mainly
169  * in icmp.c
170  */
171 
172 static __inline__ __sum16 ip_compute_csum(const void *buff, int len)
173 {
174         return csum_fold (csum_partial(buff, len, 0));
175 }
176 
177 #define _HAVE_ARCH_IPV6_CSUM
178 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
179                                           const struct in6_addr *daddr,
180                                           __u32 len, unsigned short proto,
181                                           __wsum sum)
182 {
183         unsigned int __dummy;
184         __asm__("l32i   %1, %2, 0\n\t"
185                 "add    %0, %0, %1\n\t"
186                 "bgeu   %0, %1, 1f\n\t"
187                 "addi   %0, %0, 1\n\t"
188                 "1:\t"
189                 "l32i   %1, %2, 4\n\t"
190                 "add    %0, %0, %1\n\t"
191                 "bgeu   %0, %1, 1f\n\t"
192                 "addi   %0, %0, 1\n\t"
193                 "1:\t"
194                 "l32i   %1, %2, 8\n\t"
195                 "add    %0, %0, %1\n\t"
196                 "bgeu   %0, %1, 1f\n\t"
197                 "addi   %0, %0, 1\n\t"
198                 "1:\t"
199                 "l32i   %1, %2, 12\n\t"
200                 "add    %0, %0, %1\n\t"
201                 "bgeu   %0, %1, 1f\n\t"
202                 "addi   %0, %0, 1\n\t"
203                 "1:\t"
204                 "l32i   %1, %3, 0\n\t"
205                 "add    %0, %0, %1\n\t"
206                 "bgeu   %0, %1, 1f\n\t"
207                 "addi   %0, %0, 1\n\t"
208                 "1:\t"
209                 "l32i   %1, %3, 4\n\t"
210                 "add    %0, %0, %1\n\t"
211                 "bgeu   %0, %1, 1f\n\t"
212                 "addi   %0, %0, 1\n\t"
213                 "1:\t"
214                 "l32i   %1, %3, 8\n\t"
215                 "add    %0, %0, %1\n\t"
216                 "bgeu   %0, %1, 1f\n\t"
217                 "addi   %0, %0, 1\n\t"
218                 "1:\t"
219                 "l32i   %1, %3, 12\n\t"
220                 "add    %0, %0, %1\n\t"
221                 "bgeu   %0, %1, 1f\n\t"
222                 "addi   %0, %0, 1\n\t"
223                 "1:\t"
224                 "add    %0, %0, %4\n\t"
225                 "bgeu   %0, %4, 1f\n\t"
226                 "addi   %0, %0, 1\n\t"
227                 "1:\t"
228                 "add    %0, %0, %5\n\t"
229                 "bgeu   %0, %5, 1f\n\t"
230                 "addi   %0, %0, 1\n\t"
231                 "1:\t"
232                 : "=r" (sum), "=&r" (__dummy)
233                 : "r" (saddr), "r" (daddr),
234                   "r" (htonl(len)), "r" (htonl(proto)), "" (sum)
235                 : "memory");
236 
237         return csum_fold(sum);
238 }
239 
240 /*
241  *      Copy and checksum to user
242  */
243 #define HAVE_CSUM_COPY_USER
244 static __inline__ __wsum csum_and_copy_to_user(const void *src,
245                                                void __user *dst, int len,
246                                                __wsum sum, int *err_ptr)
247 {
248         if (access_ok(VERIFY_WRITE, dst, len))
249                 return csum_partial_copy_generic(src,dst,len,sum,NULL,err_ptr);
250 
251         if (len)
252                 *err_ptr = -EFAULT;
253 
254         return (__force __wsum)-1; /* invalid checksum */
255 }
256 #endif
257 

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