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, 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         unsigned int tmp;
  42
  43         /* swap the two 16-bit halves of sum */
  44         __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (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         return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
  49 }
  50
  51 static inline u32 from64to32(u64 x)
  52 {
  53         return (x + ror64(x, 32)) >> 32;
  54 }
  55
  56 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
  57                                         __u8 proto, __wsum sum)
  58 {
  59 #ifdef __powerpc64__
  60         u64 s = (__force u32)sum;
  61
  62         s += (__force u32)saddr;
  63         s += (__force u32)daddr;
  64 #ifdef __BIG_ENDIAN__
  65         s += proto + len;
  66 #else
  67         s += (proto + len) << 8;
  68 #endif
  69         return (__force __wsum) from64to32(s);
  70 #else
  71     __asm__("\n\
  72         addc %0,%0,%1 \n\
  73         adde %0,%0,%2 \n\
  74         adde %0,%0,%3 \n\
  75         addze %0,%0 \n\
  76         "
  77         : "=r" (sum)
  78         : "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
  79         return sum;
  80 #endif
  81 }
  82
  83 /*
  84  * computes the checksum of the TCP/UDP pseudo-header
  85  * returns a 16-bit checksum, already complemented
  86  */
  87 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
  88                                         __u8 proto, __wsum sum)
  89 {
  90         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
  91 }
  92
  93 #define HAVE_ARCH_CSUM_ADD
  94 static inline __wsum csum_add(__wsum csum, __wsum addend)
  95 {
  96 #ifdef __powerpc64__
  97         u64 res = (__force u64)csum;
  98 #endif
  99         if (__builtin_constant_p(csum) && csum == 0)
 100                 return addend;
 101         if (__builtin_constant_p(addend) && addend == 0)
 102                 return csum;
 103
 104 #ifdef __powerpc64__
 105         res += (__force u64)addend;
 106         return (__force __wsum)((u32)res + (res >> 32));
 107 #else
 108         asm("addc %0,%0,%1;"
 109             "addze %0,%0;"
 110             : "+r" (csum) : "r" (addend) : "xer");
 111         return csum;
 112 #endif
 113 }
 114
 115 /*
 116  * This is a version of ip_compute_csum() optimized for IP headers,
 117  * which always checksum on 4 octet boundaries.  ihl is the number
 118  * of 32-bit words and is always >= 5.
 119  */
 120 static inline __wsum ip_fast_csum_nofold(const void *iph, unsigned int ihl)
 121 {
 122         const u32 *ptr = (const u32 *)iph + 1;
 123 #ifdef __powerpc64__
 124         unsigned int i;
 125         u64 s = *(const u32 *)iph;
 126
 127         for (i = 0; i < ihl - 1; i++, ptr++)
 128                 s += *ptr;
 129         return (__force __wsum)from64to32(s);
 130 #else
 131         __wsum sum, tmp;
 132
 133         asm("mtctr %3;"
 134             "addc %0,%4,%5;"
 135             "1: lwzu %1, 4(%2);"
 136             "adde %0,%0,%1;"
 137             "bdnz 1b;"
 138             "addze %0,%0;"
 139             : "=r" (sum), "=r" (tmp), "+b" (ptr)
 140             : "r" (ihl - 2), "r" (*(const u32 *)iph), "r" (*ptr)
 141             : "ctr", "xer", "memory");
 142
 143         return sum;
 144 #endif
 145 }
 146
 147 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
 148 {
 149         return csum_fold(ip_fast_csum_nofold(iph, ihl));
 150 }
 151
 152 /*
 153  * computes the checksum of a memory block at buff, length len,
 154  * and adds in "sum" (32-bit)
 155  *
 156  * returns a 32-bit number suitable for feeding into itself
 157  * or csum_tcpudp_magic
 158  *
 159  * this function must be called with even lengths, except
 160  * for the last fragment, which may be odd
 161  *
 162  * it's best to have buff aligned on a 32-bit boundary
 163  */
 164 __wsum __csum_partial(const void *buff, int len, __wsum sum);
 165
 166 static __always_inline __wsum csum_partial(const void *buff, int len, __wsum sum)
 167 {
 168         if (__builtin_constant_p(len) && len <= 16 && (len & 1) == 0) {
 169                 if (len == 2)
 170                         sum = csum_add(sum, (__force __wsum)*(const u16 *)buff);
 171                 if (len >= 4)
 172                         sum = csum_add(sum, (__force __wsum)*(const u32 *)buff);
 173                 if (len == 6)
 174                         sum = csum_add(sum, (__force __wsum)
 175                                             *(const u16 *)(buff + 4));
 176                 if (len >= 8)
 177                         sum = csum_add(sum, (__force __wsum)
 178                                             *(const u32 *)(buff + 4));
 179                 if (len == 10)
 180                         sum = csum_add(sum, (__force __wsum)
 181                                             *(const u16 *)(buff + 8));
 182                 if (len >= 12)
 183                         sum = csum_add(sum, (__force __wsum)
 184                                             *(const u32 *)(buff + 8));
 185                 if (len == 14)
 186                         sum = csum_add(sum, (__force __wsum)
 187                                             *(const u16 *)(buff + 12));
 188                 if (len >= 16)
 189                         sum = csum_add(sum, (__force __wsum)
 190                                             *(const u32 *)(buff + 12));
 191         } else if (__builtin_constant_p(len) && (len & 3) == 0) {
 192                 sum = csum_add(sum, ip_fast_csum_nofold(buff, len >> 2));
 193         } else {
 194                 sum = __csum_partial(buff, len, sum);
 195         }
 196         return sum;
 197 }
 198
 199 /*
 200  * this routine is used for miscellaneous IP-like checksums, mainly
 201  * in icmp.c
 202  */
 203 static inline __sum16 ip_compute_csum(const void *buff, int len)
 204 {
 205         return csum_fold(csum_partial(buff, len, 0));
 206 }
 207
 208 #define _HAVE_ARCH_IPV6_CSUM
 209 __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 210                         const struct in6_addr *daddr,
 211                         __u32 len, __u8 proto, __wsum sum);
 212
 213 #endif /* __KERNEL__ */
 214 #endif