arch/powerpc/include/asm/checksum.h

   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,
  22                                               int len, __wsum sum,
  23                                               int *src_err, int *dst_err);
  24
  25 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  26 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
  27                                       int len, __wsum sum, int *err_ptr);
  28 #define HAVE_CSUM_COPY_USER
  29 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
  30                                     int len, __wsum sum, int *err_ptr);
  31
  32 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  33         csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
  34
  35
  36 /*
  37  * turns a 32-bit partial checksum (e.g. from csum_partial) into a
  38  * 1's complement 16-bit checksum.
  39  */
  40 static inline __sum16 csum_fold(__wsum sum)
  41 {
  42         unsigned int tmp;
  43
  44         /* swap the two 16-bit halves of sum */
  45         __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
  46         /* if there is a carry from adding the two 16-bit halves,
  47            it will carry from the lower half into the upper half,
  48            giving us the correct sum in the upper half. */
  49         return (__force __sum16)(~((__force u32)sum + tmp) >> 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), "0"(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 inline __wsum csum_add(__wsum csum, __wsum addend)
  96 {
  97 #ifdef __powerpc64__
  98         u64 res = (__force u64)csum;
  99 #endif
 100         if (__builtin_constant_p(csum) && csum == 0)
 101                 return addend;
 102         if (__builtin_constant_p(addend) && addend == 0)
 103                 return csum;
 104
 105 #ifdef __powerpc64__
 106         res += (__force u64)addend;
 107         return (__force __wsum)((u32)res + (res >> 32));
 108 #else
 109         asm("addc %0,%0,%1;"
 110             "addze %0,%0;"
 111             : "+r" (csum) : "r" (addend) : "xer");
 112         return csum;
 113 #endif
 114 }
 115
 116 /*
 117  * This is a version of ip_compute_csum() optimized for IP headers,
 118  * which always checksum on 4 octet boundaries.  ihl is the number
 119  * of 32-bit words and is always >= 5.
 120  */
 121 static inline __wsum ip_fast_csum_nofold(const void *iph, unsigned int ihl)
 122 {
 123         const u32 *ptr = (const u32 *)iph + 1;
 124 #ifdef __powerpc64__
 125         unsigned int i;
 126         u64 s = *(const u32 *)iph;
 127
 128         for (i = 0; i < ihl - 1; i++, ptr++)
 129                 s += *ptr;
 130         return (__force __wsum)from64to32(s);
 131 #else
 132         __wsum sum, tmp;
 133
 134         asm("mtctr %3;"
 135             "addc %0,%4,%5;"
 136             "1: lwzu %1, 4(%2);"
 137             "adde %0,%0,%1;"
 138             "bdnz 1b;"
 139             "addze %0,%0;"
 140             : "=r" (sum), "=r" (tmp), "+b" (ptr)
 141             : "r" (ihl - 2), "r" (*(const u32 *)iph), "r" (*ptr)
 142             : "ctr", "xer", "memory");
 143
 144         return sum;
 145 #endif
 146 }
 147
 148 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
 149 {
 150         return csum_fold(ip_fast_csum_nofold(iph, ihl));
 151 }
 152
 153 /*
 154  * computes the checksum of a memory block at buff, length len,
 155  * and adds in "sum" (32-bit)
 156  *
 157  * returns a 32-bit number suitable for feeding into itself
 158  * or csum_tcpudp_magic
 159  *
 160  * this function must be called with even lengths, except
 161  * for the last fragment, which may be odd
 162  *
 163  * it's best to have buff aligned on a 32-bit boundary
 164  */
 165 __wsum __csum_partial(const void *buff, int len, __wsum sum);
 166
 167 static inline __wsum csum_partial(const void *buff, int len, __wsum sum)
 168 {
 169         if (__builtin_constant_p(len) && len <= 16 && (len & 1) == 0) {
 170                 if (len == 2)
 171                         sum = csum_add(sum, (__force __wsum)*(const u16 *)buff);
 172                 if (len >= 4)
 173                         sum = csum_add(sum, (__force __wsum)*(const u32 *)buff);
 174                 if (len == 6)
 175                         sum = csum_add(sum, (__force __wsum)
 176                                             *(const u16 *)(buff + 4));
 177                 if (len >= 8)
 178                         sum = csum_add(sum, (__force __wsum)
 179                                             *(const u32 *)(buff + 4));
 180                 if (len == 10)
 181                         sum = csum_add(sum, (__force __wsum)
 182                                             *(const u16 *)(buff + 8));
 183                 if (len >= 12)
 184                         sum = csum_add(sum, (__force __wsum)
 185                                             *(const u32 *)(buff + 8));
 186                 if (len == 14)
 187                         sum = csum_add(sum, (__force __wsum)
 188                                             *(const u16 *)(buff + 12));
 189                 if (len >= 16)
 190                         sum = csum_add(sum, (__force __wsum)
 191                                             *(const u32 *)(buff + 12));
 192         } else if (__builtin_constant_p(len) && (len & 3) == 0) {
 193                 sum = csum_add(sum, ip_fast_csum_nofold(buff, len >> 2));
 194         } else {
 195                 sum = __csum_partial(buff, len, sum);
 196         }
 197         return sum;
 198 }
 199
 200 /*
 201  * this routine is used for miscellaneous IP-like checksums, mainly
 202  * in icmp.c
 203  */
 204 static inline __sum16 ip_compute_csum(const void *buff, int len)
 205 {
 206         return csum_fold(csum_partial(buff, len, 0));
 207 }
 208
 209 #define _HAVE_ARCH_IPV6_CSUM
 210 __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 211                         const struct in6_addr *daddr,
 212                         __u32 len, __u8 proto, __wsum sum);
 213
 214 #endif /* __KERNEL__ */
 215 #endif