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

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  1 /* SPDX-License-Identifier: GPL-2.0-or-later */
  2 #ifndef _ASM_POWERPC_CHECKSUM_H
  3 #define _ASM_POWERPC_CHECKSUM_H
  4 #ifdef __KERNEL__
  5 
  6 /*
  7  */
  8 
  9 #include <linux/bitops.h>
 10 #include <linux/in6.h>
 11 /*
 12  * Computes the checksum of a memory block at src, length len,
 13  * and adds in "sum" (32-bit), while copying the block to dst.
 14  * If an access exception occurs on src or dst, it stores -EFAULT
 15  * to *src_err or *dst_err respectively (if that pointer is not
 16  * NULL), and, for an error on src, zeroes the rest of dst.
 17  *
 18  * Like csum_partial, this must be called with even lengths,
 19  * except for the last fragment.
 20  */
 21 extern __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
 22 
 23 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 24 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 25                                       int len);
 26 #define HAVE_CSUM_COPY_USER
 27 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 28                                     int len);
 29 
 30 #define _HAVE_ARCH_CSUM_AND_COPY
 31 #define csum_partial_copy_nocheck(src, dst, len)   \
 32         csum_partial_copy_generic((src), (dst), (len))
 33 
 34 
 35 /*
 36  * turns a 32-bit partial checksum (e.g. from csum_partial) into a
 37  * 1's complement 16-bit checksum.
 38  */
 39 static inline __sum16 csum_fold(__wsum sum)
 40 {
 41         u32 tmp = (__force u32)sum;
 42 
 43         /*
 44          * swap the two 16-bit halves of sum
 45          * if there is a carry from adding the two 16-bit halves,
 46          * it will carry from the lower half into the upper half,
 47          * giving us the correct sum in the upper half.
 48          */
 49         return (__force __sum16)(~(tmp + rol32(tmp, 16)) >> 16);
 50 }
 51 
 52 static inline u32 from64to32(u64 x)
 53 {
 54         return (x + ror64(x, 32)) >> 32;
 55 }
 56 
 57 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
 58                                         __u8 proto, __wsum sum)
 59 {
 60 #ifdef __powerpc64__
 61         u64 s = (__force u32)sum;
 62 
 63         s += (__force u32)saddr;
 64         s += (__force u32)daddr;
 65 #ifdef __BIG_ENDIAN__
 66         s += proto + len;
 67 #else
 68         s += (proto + len) << 8;
 69 #endif
 70         return (__force __wsum) from64to32(s);
 71 #else
 72     __asm__("\n\
 73         addc %0,%0,%1 \n\
 74         adde %0,%0,%2 \n\
 75         adde %0,%0,%3 \n\
 76         addze %0,%0 \n\
 77         "
 78         : "=r" (sum)
 79         : "r" (daddr), "r"(saddr), "r"(proto + len), ""(sum));
 80         return sum;
 81 #endif
 82 }
 83 
 84 /*
 85  * computes the checksum of the TCP/UDP pseudo-header
 86  * returns a 16-bit checksum, already complemented
 87  */
 88 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
 89                                         __u8 proto, __wsum sum)
 90 {
 91         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 92 }
 93 
 94 #define HAVE_ARCH_CSUM_ADD
 95 static __always_inline __wsum csum_add(__wsum csum, __wsum addend)
 96 {
 97 #ifdef __powerpc64__
 98         u64 res = (__force u64)csum;
 99 
100         res += (__force u64)addend;
101         return (__force __wsum)((u32)res + (res >> 32));
102 #else
103         if (__builtin_constant_p(csum) && csum == 0)
104                 return addend;
105         if (__builtin_constant_p(addend) && addend == 0)
106                 return csum;
107 
108         asm("addc %0,%0,%1;"
109             "addze %0,%0;"
110             : "+r" (csum) : "r" (addend) : "xer");
111         return csum;
112 #endif
113 }
114 
115 #define HAVE_ARCH_CSUM_SHIFT
116 static __always_inline __wsum csum_shift(__wsum sum, int offset)
117 {
118         /* rotate sum to align it with a 16b boundary */
119         return (__force __wsum)rol32((__force u32)sum, (offset & 1) << 3);
120 }
121 
122 /*
123  * This is a version of ip_compute_csum() optimized for IP headers,
124  * which always checksum on 4 octet boundaries.  ihl is the number
125  * of 32-bit words and is always >= 5.
126  */
127 static inline __wsum ip_fast_csum_nofold(const void *iph, unsigned int ihl)
128 {
129         const u32 *ptr = (const u32 *)iph + 1;
130 #ifdef __powerpc64__
131         unsigned int i;
132         u64 s = *(const u32 *)iph;
133 
134         for (i = 0; i < ihl - 1; i++, ptr++)
135                 s += *ptr;
136         return (__force __wsum)from64to32(s);
137 #else
138         __wsum sum, tmp;
139 
140         asm("mtctr %3;"
141             "addc %0,%4,%5;"
142             "1: lwzu %1, 4(%2);"
143             "adde %0,%0,%1;"
144             "bdnz 1b;"
145             "addze %0,%0;"
146             : "=r" (sum), "=r" (tmp), "+b" (ptr)
147             : "r" (ihl - 2), "r" (*(const u32 *)iph), "r" (*ptr)
148             : "ctr", "xer", "memory");
149 
150         return sum;
151 #endif
152 }
153 
154 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
155 {
156         return csum_fold(ip_fast_csum_nofold(iph, ihl));
157 }
158 
159 /*
160  * computes the checksum of a memory block at buff, length len,
161  * and adds in "sum" (32-bit)
162  *
163  * returns a 32-bit number suitable for feeding into itself
164  * or csum_tcpudp_magic
165  *
166  * this function must be called with even lengths, except
167  * for the last fragment, which may be odd
168  *
169  * it's best to have buff aligned on a 32-bit boundary
170  */
171 __wsum __csum_partial(const void *buff, int len, __wsum sum);
172 
173 static __always_inline __wsum csum_partial(const void *buff, int len, __wsum sum)
174 {
175         if (__builtin_constant_p(len) && len <= 16 && (len & 1) == 0) {
176                 if (len == 2)
177                         sum = csum_add(sum, (__force __wsum)*(const u16 *)buff);
178                 if (len >= 4)
179                         sum = csum_add(sum, (__force __wsum)*(const u32 *)buff);
180                 if (len == 6)
181                         sum = csum_add(sum, (__force __wsum)
182                                             *(const u16 *)(buff + 4));
183                 if (len >= 8)
184                         sum = csum_add(sum, (__force __wsum)
185                                             *(const u32 *)(buff + 4));
186                 if (len == 10)
187                         sum = csum_add(sum, (__force __wsum)
188                                             *(const u16 *)(buff + 8));
189                 if (len >= 12)
190                         sum = csum_add(sum, (__force __wsum)
191                                             *(const u32 *)(buff + 8));
192                 if (len == 14)
193                         sum = csum_add(sum, (__force __wsum)
194                                             *(const u16 *)(buff + 12));
195                 if (len >= 16)
196                         sum = csum_add(sum, (__force __wsum)
197                                             *(const u32 *)(buff + 12));
198         } else if (__builtin_constant_p(len) && (len & 3) == 0) {
199                 sum = csum_add(sum, ip_fast_csum_nofold(buff, len >> 2));
200         } else {
201                 sum = __csum_partial(buff, len, sum);
202         }
203         return sum;
204 }
205 
206 /*
207  * this routine is used for miscellaneous IP-like checksums, mainly
208  * in icmp.c
209  */
210 static inline __sum16 ip_compute_csum(const void *buff, int len)
211 {
212         return csum_fold(csum_partial(buff, len, 0));
213 }
214 
215 #define _HAVE_ARCH_IPV6_CSUM
216 __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
217                         const struct in6_addr *daddr,
218                         __u32 len, __u8 proto, __wsum sum);
219 
220 #endif /* __KERNEL__ */
221 #endif
222 

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