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 #include <linux/uaccess.h>
  11
  12 /*
  13  * computes the checksum of a memory block at buff, length len,
  14  * and adds in "sum" (32-bit)
  15  *
  16  * returns a 32-bit number suitable for feeding into itself
  17  * or csum_tcpudp_magic
  18  *
  19  * this function must be called with even lengths, except
  20  * for the last fragment, which may be odd
  21  *
  22  * it's best to have buff aligned on a 32-bit boundary
  23  */
  24 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  25
  26 /*
  27  * the same as csum_partial, but copies from src while it
  28  * checksums, and handles user-space pointer exceptions correctly, when needed.
  29  *
  30  * here even more important to align src and dst on a 32-bit (or even
  31  * better 64-bit) boundary
  32  */
  33
  34 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
  35
  36 #define _HAVE_ARCH_CSUM_AND_COPY
  37 /*
  38  *      Note: when you get a NULL pointer exception here this means someone
  39  *      passed in an incorrect kernel address to one of these functions.
  40  *
  41  *      If you use these functions directly please don't forget the
  42  *      access_ok().
  43  */
  44 static inline
  45 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
  46 {
  47         return csum_partial_copy_generic(src, dst, len);
  48 }
  49
  50 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  51 static inline
  52 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
  53 {
  54         if (!access_ok(src, len))
  55                 return 0;
  56         return csum_partial_copy_generic((__force const void *)src, dst, len);
  57 }
  58
  59 /*
  60  *      Fold a partial checksum
  61  */
  62
  63 static inline __sum16 csum_fold(__wsum sum)
  64 {
  65         unsigned int __dummy;
  66         __asm__("swap.w %0, %1\n\t"
  67                 "extu.w %0, %0\n\t"
  68                 "extu.w %1, %1\n\t"
  69                 "add    %1, %0\n\t"
  70                 "swap.w %0, %1\n\t"
  71                 "add    %1, %0\n\t"
  72                 "not    %0, %0\n\t"
  73                 : "=r" (sum), "=&r" (__dummy)
  74                 : "0" (sum)
  75                 : "t");
  76         return (__force __sum16)sum;
  77 }
  78
  79 /*
  80  *      This is a version of ip_compute_csum() optimized for IP headers,
  81  *      which always checksum on 4 octet boundaries.
  82  *
  83  *      i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
  84  *      for linux by * Arnt Gulbrandsen.
  85  */
  86 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  87 {
  88         __wsum sum;
  89         unsigned int __dummy0, __dummy1;
  90
  91         __asm__ __volatile__(
  92                 "mov.l  @%1+, %0\n\t"
  93                 "mov.l  @%1+, %3\n\t"
  94                 "add    #-2, %2\n\t"
  95                 "clrt\n\t"
  96                 "1:\t"
  97                 "addc   %3, %0\n\t"
  98                 "movt   %4\n\t"
  99                 "mov.l  @%1+, %3\n\t"
 100                 "dt     %2\n\t"
 101                 "bf/s   1b\n\t"
 102                 " cmp/eq #1, %4\n\t"
 103                 "addc   %3, %0\n\t"
 104                 "addc   %2, %0"     /* Here %2 is 0, add carry-bit */
 105         /* Since the input registers which are loaded with iph and ihl
 106            are modified, we must also specify them as outputs, or gcc
 107            will assume they contain their original values. */
 108         : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
 109         : "1" (iph), "2" (ihl)
 110         : "t", "memory");
 111
 112         return  csum_fold(sum);
 113 }
 114
 115 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 116                                         __u32 len, __u8 proto,
 117                                         __wsum sum)
 118 {
 119 #ifdef __LITTLE_ENDIAN__
 120         unsigned long len_proto = (proto + len) << 8;
 121 #else
 122         unsigned long len_proto = proto + len;
 123 #endif
 124         __asm__("clrt\n\t"
 125                 "addc   %0, %1\n\t"
 126                 "addc   %2, %1\n\t"
 127                 "addc   %3, %1\n\t"
 128                 "movt   %0\n\t"
 129                 "add    %1, %0"
 130                 : "=r" (sum), "=r" (len_proto)
 131                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
 132                 : "t");
 133
 134         return sum;
 135 }
 136
 137 /*
 138  * computes the checksum of the TCP/UDP pseudo-header
 139  * returns a 16-bit checksum, already complemented
 140  */
 141 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 142                                         __u32 len, __u8 proto,
 143                                         __wsum sum)
 144 {
 145         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 146 }
 147
 148 /*
 149  * this routine is used for miscellaneous IP-like checksums, mainly
 150  * in icmp.c
 151  */
 152 static inline __sum16 ip_compute_csum(const void *buff, int len)
 153 {
 154     return csum_fold(csum_partial(buff, len, 0));
 155 }
 156
 157 #define _HAVE_ARCH_IPV6_CSUM
 158 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 159                                       const struct in6_addr *daddr,
 160                                       __u32 len, __u8 proto, __wsum sum)
 161 {
 162         unsigned int __dummy;
 163         __asm__("clrt\n\t"
 164                 "mov.l  @(0,%2), %1\n\t"
 165                 "addc   %1, %0\n\t"
 166                 "mov.l  @(4,%2), %1\n\t"
 167                 "addc   %1, %0\n\t"
 168                 "mov.l  @(8,%2), %1\n\t"
 169                 "addc   %1, %0\n\t"
 170                 "mov.l  @(12,%2), %1\n\t"
 171                 "addc   %1, %0\n\t"
 172                 "mov.l  @(0,%3), %1\n\t"
 173                 "addc   %1, %0\n\t"
 174                 "mov.l  @(4,%3), %1\n\t"
 175                 "addc   %1, %0\n\t"
 176                 "mov.l  @(8,%3), %1\n\t"
 177                 "addc   %1, %0\n\t"
 178                 "mov.l  @(12,%3), %1\n\t"
 179                 "addc   %1, %0\n\t"
 180                 "addc   %4, %0\n\t"
 181                 "addc   %5, %0\n\t"
 182                 "movt   %1\n\t"
 183                 "add    %1, %0\n"
 184                 : "=r" (sum), "=&r" (__dummy)
 185                 : "r" (saddr), "r" (daddr),
 186                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
 187                 : "t");
 188
 189         return csum_fold(sum);
 190 }
 191
 192 /*
 193  *      Copy and checksum to user
 194  */
 195 #define HAVE_CSUM_COPY_USER
 196 static inline __wsum csum_and_copy_to_user(const void *src,
 197                                            void __user *dst,
 198                                            int len)
 199 {
 200         if (!access_ok(dst, len))
 201                 return 0;
 202         return csum_partial_copy_generic(src, (__force void *)dst, len);
 203 }
 204 #endif /* __ASM_SH_CHECKSUM_H */