arch/sh/include/asm/checksum_32.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_SH_CHECKSUM_H
   3 #define __ASM_SH_CHECKSUM_H
   4
   5 /*
   6  * Copyright (C) 1999 by Kaz Kojima & Niibe Yutaka
   7  */
   8
   9 #include <linux/in6.h>
  10
  11 /*
  12  * computes the checksum of a memory block at buff, length len,
  13  * and adds in "sum" (32-bit)
  14  *
  15  * returns a 32-bit number suitable for feeding into itself
  16  * or csum_tcpudp_magic
  17  *
  18  * this function must be called with even lengths, except
  19  * for the last fragment, which may be odd
  20  *
  21  * it's best to have buff aligned on a 32-bit boundary
  22  */
  23 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  24
  25 /*
  26  * the same as csum_partial, but copies from src while it
  27  * checksums, and handles user-space pointer exceptions correctly, when needed.
  28  *
  29  * here even more important to align src and dst on a 32-bit (or even
  30  * better 64-bit) boundary
  31  */
  32
  33 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
  34
  35 #define _HAVE_ARCH_CSUM_AND_COPY
  36 /*
  37  *      Note: when you get a NULL pointer exception here this means someone
  38  *      passed in an incorrect kernel address to one of these functions.
  39  *
  40  *      If you use these functions directly please don't forget the
  41  *      access_ok().
  42  */
  43 static inline
  44 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
  45 {
  46         return csum_partial_copy_generic(src, dst, len);
  47 }
  48
  49 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  50 static inline
  51 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
  52 {
  53         if (!access_ok(src, len))
  54                 return 0;
  55         return csum_partial_copy_generic((__force const void *)src, dst, len);
  56 }
  57
  58 /*
  59  *      Fold a partial checksum
  60  */
  61
  62 static inline __sum16 csum_fold(__wsum sum)
  63 {
  64         unsigned int __dummy;
  65         __asm__("swap.w %0, %1\n\t"
  66                 "extu.w %0, %0\n\t"
  67                 "extu.w %1, %1\n\t"
  68                 "add    %1, %0\n\t"
  69                 "swap.w %0, %1\n\t"
  70                 "add    %1, %0\n\t"
  71                 "not    %0, %0\n\t"
  72                 : "=r" (sum), "=&r" (__dummy)
  73                 : "0" (sum)
  74                 : "t");
  75         return (__force __sum16)sum;
  76 }
  77
  78 /*
  79  *      This is a version of ip_compute_csum() optimized for IP headers,
  80  *      which always checksum on 4 octet boundaries.
  81  *
  82  *      i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
  83  *      for linux by * Arnt Gulbrandsen.
  84  */
  85 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  86 {
  87         unsigned int sum, __dummy0, __dummy1;
  88
  89         __asm__ __volatile__(
  90                 "mov.l  @%1+, %0\n\t"
  91                 "mov.l  @%1+, %3\n\t"
  92                 "add    #-2, %2\n\t"
  93                 "clrt\n\t"
  94                 "1:\t"
  95                 "addc   %3, %0\n\t"
  96                 "movt   %4\n\t"
  97                 "mov.l  @%1+, %3\n\t"
  98                 "dt     %2\n\t"
  99                 "bf/s   1b\n\t"
 100                 " cmp/eq #1, %4\n\t"
 101                 "addc   %3, %0\n\t"
 102                 "addc   %2, %0"     /* Here %2 is 0, add carry-bit */
 103         /* Since the input registers which are loaded with iph and ihl
 104            are modified, we must also specify them as outputs, or gcc
 105            will assume they contain their original values. */
 106         : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
 107         : "1" (iph), "2" (ihl)
 108         : "t", "memory");
 109
 110         return  csum_fold(sum);
 111 }
 112
 113 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 114                                         __u32 len, __u8 proto,
 115                                         __wsum sum)
 116 {
 117 #ifdef __LITTLE_ENDIAN__
 118         unsigned long len_proto = (proto + len) << 8;
 119 #else
 120         unsigned long len_proto = proto + len;
 121 #endif
 122         __asm__("clrt\n\t"
 123                 "addc   %0, %1\n\t"
 124                 "addc   %2, %1\n\t"
 125                 "addc   %3, %1\n\t"
 126                 "movt   %0\n\t"
 127                 "add    %1, %0"
 128                 : "=r" (sum), "=r" (len_proto)
 129                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
 130                 : "t");
 131
 132         return sum;
 133 }
 134
 135 /*
 136  * computes the checksum of the TCP/UDP pseudo-header
 137  * returns a 16-bit checksum, already complemented
 138  */
 139 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 140                                         __u32 len, __u8 proto,
 141                                         __wsum sum)
 142 {
 143         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 144 }
 145
 146 /*
 147  * this routine is used for miscellaneous IP-like checksums, mainly
 148  * in icmp.c
 149  */
 150 static inline __sum16 ip_compute_csum(const void *buff, int len)
 151 {
 152     return csum_fold(csum_partial(buff, len, 0));
 153 }
 154
 155 #define _HAVE_ARCH_IPV6_CSUM
 156 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 157                                       const struct in6_addr *daddr,
 158                                       __u32 len, __u8 proto, __wsum sum)
 159 {
 160         unsigned int __dummy;
 161         __asm__("clrt\n\t"
 162                 "mov.l  @(0,%2), %1\n\t"
 163                 "addc   %1, %0\n\t"
 164                 "mov.l  @(4,%2), %1\n\t"
 165                 "addc   %1, %0\n\t"
 166                 "mov.l  @(8,%2), %1\n\t"
 167                 "addc   %1, %0\n\t"
 168                 "mov.l  @(12,%2), %1\n\t"
 169                 "addc   %1, %0\n\t"
 170                 "mov.l  @(0,%3), %1\n\t"
 171                 "addc   %1, %0\n\t"
 172                 "mov.l  @(4,%3), %1\n\t"
 173                 "addc   %1, %0\n\t"
 174                 "mov.l  @(8,%3), %1\n\t"
 175                 "addc   %1, %0\n\t"
 176                 "mov.l  @(12,%3), %1\n\t"
 177                 "addc   %1, %0\n\t"
 178                 "addc   %4, %0\n\t"
 179                 "addc   %5, %0\n\t"
 180                 "movt   %1\n\t"
 181                 "add    %1, %0\n"
 182                 : "=r" (sum), "=&r" (__dummy)
 183                 : "r" (saddr), "r" (daddr),
 184                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
 185                 : "t");
 186
 187         return csum_fold(sum);
 188 }
 189
 190 /*
 191  *      Copy and checksum to user
 192  */
 193 #define HAVE_CSUM_COPY_USER
 194 static inline __wsum csum_and_copy_to_user(const void *src,
 195                                            void __user *dst,
 196                                            int len)
 197 {
 198         if (!access_ok(dst, len))
 199                 return 0;
 200         return csum_partial_copy_generic((__force const void *)src, dst, len);
 201 }
 202 #endif /* __ASM_SH_CHECKSUM_H */