root/arch/sh/include/asm/checksum_32.h

INCLUDED FROM

DEFINITIONS

1. csum_partial_copy_nocheck
2. csum_partial_copy_from_user
3. csum_fold
4. ip_fast_csum
5. csum_tcpudp_nofold
6. csum_tcpudp_magic
7. ip_compute_csum
8. csum_ipv6_magic
9. csum_and_copy_to_user

   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,
  34                                             int len, __wsum sum,
  35                                             int *src_err_ptr, int *dst_err_ptr);
  36 
  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,
  46                                  int len, __wsum sum)
  47 {
  48         return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
  49 }
  50 
  51 static inline
  52 __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  53                                    int len, __wsum sum, int *err_ptr)
  54 {
  55         return csum_partial_copy_generic((__force const void *)src, dst,
  56                                         len, sum, err_ptr, NULL);
  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         unsigned int sum, __dummy0, __dummy1;
  89 
  90         __asm__ __volatile__(
  91                 "mov.l  @%1+, %0\n\t"
  92                 "mov.l  @%1+, %3\n\t"
  93                 "add    #-2, %2\n\t"
  94                 "clrt\n\t"
  95                 "1:\t"
  96                 "addc   %3, %0\n\t"
  97                 "movt   %4\n\t"
  98                 "mov.l  @%1+, %3\n\t"
  99                 "dt     %2\n\t"
 100                 "bf/s   1b\n\t"
 101                 " cmp/eq #1, %4\n\t"
 102                 "addc   %3, %0\n\t"
 103                 "addc   %2, %0"     /* Here %2 is 0, add carry-bit */
 104         /* Since the input registers which are loaded with iph and ihl
 105            are modified, we must also specify them as outputs, or gcc
 106            will assume they contain their original values. */
 107         : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
 108         : "1" (iph), "2" (ihl)
 109         : "t", "memory");
 110 
 111         return  csum_fold(sum);
 112 }
 113 
 114 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 115                                         __u32 len, __u8 proto,
 116                                         __wsum sum)
 117 {
 118 #ifdef __LITTLE_ENDIAN__
 119         unsigned long len_proto = (proto + len) << 8;
 120 #else
 121         unsigned long len_proto = proto + len;
 122 #endif
 123         __asm__("clrt\n\t"
 124                 "addc   %0, %1\n\t"
 125                 "addc   %2, %1\n\t"
 126                 "addc   %3, %1\n\t"
 127                 "movt   %0\n\t"
 128                 "add    %1, %0"
 129                 : "=r" (sum), "=r" (len_proto)
 130                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
 131                 : "t");
 132 
 133         return sum;
 134 }
 135 
 136 /*
 137  * computes the checksum of the TCP/UDP pseudo-header
 138  * returns a 16-bit checksum, already complemented
 139  */
 140 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 141                                         __u32 len, __u8 proto,
 142                                         __wsum sum)
 143 {
 144         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 145 }
 146 
 147 /*
 148  * this routine is used for miscellaneous IP-like checksums, mainly
 149  * in icmp.c
 150  */
 151 static inline __sum16 ip_compute_csum(const void *buff, int len)
 152 {
 153     return csum_fold(csum_partial(buff, len, 0));
 154 }
 155 
 156 #define _HAVE_ARCH_IPV6_CSUM
 157 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 158                                       const struct in6_addr *daddr,
 159                                       __u32 len, __u8 proto, __wsum sum)
 160 {
 161         unsigned int __dummy;
 162         __asm__("clrt\n\t"
 163                 "mov.l  @(0,%2), %1\n\t"
 164                 "addc   %1, %0\n\t"
 165                 "mov.l  @(4,%2), %1\n\t"
 166                 "addc   %1, %0\n\t"
 167                 "mov.l  @(8,%2), %1\n\t"
 168                 "addc   %1, %0\n\t"
 169                 "mov.l  @(12,%2), %1\n\t"
 170                 "addc   %1, %0\n\t"
 171                 "mov.l  @(0,%3), %1\n\t"
 172                 "addc   %1, %0\n\t"
 173                 "mov.l  @(4,%3), %1\n\t"
 174                 "addc   %1, %0\n\t"
 175                 "mov.l  @(8,%3), %1\n\t"
 176                 "addc   %1, %0\n\t"
 177                 "mov.l  @(12,%3), %1\n\t"
 178                 "addc   %1, %0\n\t"
 179                 "addc   %4, %0\n\t"
 180                 "addc   %5, %0\n\t"
 181                 "movt   %1\n\t"
 182                 "add    %1, %0\n"
 183                 : "=r" (sum), "=&r" (__dummy)
 184                 : "r" (saddr), "r" (daddr),
 185                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
 186                 : "t");
 187 
 188         return csum_fold(sum);
 189 }
 190 
 191 /*
 192  *      Copy and checksum to user
 193  */
 194 #define HAVE_CSUM_COPY_USER
 195 static inline __wsum csum_and_copy_to_user(const void *src,
 196                                            void __user *dst,
 197                                            int len, __wsum sum,
 198                                            int *err_ptr)
 199 {
 200         if (access_ok(dst, len))
 201                 return csum_partial_copy_generic((__force const void *)src,
 202                                                 dst, len, sum, NULL, err_ptr);
 203 
 204         if (len)
 205                 *err_ptr = -EFAULT;
 206 
 207         return (__force __wsum)-1; /* invalid checksum */
 208 }
 209 #endif /* __ASM_SH_CHECKSUM_H */