linux/arch/parisc/include/asm/checksum.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _PARISC_CHECKSUM_H
   3#define _PARISC_CHECKSUM_H
   4
   5#include <linux/in6.h>
   6
   7/*
   8 * computes the checksum of a memory block at buff, length len,
   9 * and adds in "sum" (32-bit)
  10 *
  11 * returns a 32-bit number suitable for feeding into itself
  12 * or csum_tcpudp_magic
  13 *
  14 * this function must be called with even lengths, except
  15 * for the last fragment, which may be odd
  16 *
  17 * it's best to have buff aligned on a 32-bit boundary
  18 */
  19extern __wsum csum_partial(const void *, int, __wsum);
  20
  21/*
  22 *      Optimized for IP headers, which always checksum on 4 octet boundaries.
  23 *
  24 *      Written by Randolph Chung <tausq@debian.org>, and then mucked with by
  25 *      LaMont Jones <lamont@debian.org>
  26 */
  27static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  28{
  29        unsigned int sum;
  30        unsigned long t0, t1, t2;
  31
  32        __asm__ __volatile__ (
  33"       ldws,ma         4(%1), %0\n"
  34"       addib,<=        -4, %2, 2f\n"
  35"\n"
  36"       ldws            4(%1), %4\n"
  37"       ldws            8(%1), %5\n"
  38"       add             %0, %4, %0\n"
  39"       ldws,ma         12(%1), %3\n"
  40"       addc            %0, %5, %0\n"
  41"       addc            %0, %3, %0\n"
  42"1:     ldws,ma         4(%1), %3\n"
  43"       addib,<         0, %2, 1b\n"
  44"       addc            %0, %3, %0\n"
  45"\n"
  46"       extru           %0, 31, 16, %4\n"
  47"       extru           %0, 15, 16, %5\n"
  48"       addc            %4, %5, %0\n"
  49"       extru           %0, 15, 16, %5\n"
  50"       add             %0, %5, %0\n"
  51"       subi            -1, %0, %0\n"
  52"2:\n"
  53        : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (t0), "=r" (t1), "=r" (t2)
  54        : "1" (iph), "2" (ihl)
  55        : "memory");
  56
  57        return (__force __sum16)sum;
  58}
  59
  60/*
  61 *      Fold a partial checksum
  62 */
  63static inline __sum16 csum_fold(__wsum csum)
  64{
  65        u32 sum = (__force u32)csum;
  66        /* add the swapped two 16-bit halves of sum,
  67           a possible carry from adding the two 16-bit halves,
  68           will carry from the lower half into the upper half,
  69           giving us the correct sum in the upper half. */
  70        sum += (sum << 16) + (sum >> 16);
  71        return (__force __sum16)(~sum >> 16);
  72}
  73 
  74static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  75                                        __u32 len, __u8 proto,
  76                                        __wsum sum)
  77{
  78        __asm__(
  79        "       add  %1, %0, %0\n"
  80        "       addc %2, %0, %0\n"
  81        "       addc %3, %0, %0\n"
  82        "       addc %%r0, %0, %0\n"
  83                : "=r" (sum)
  84                : "r" (daddr), "r"(saddr), "r"(proto+len), "0"(sum));
  85        return sum;
  86}
  87
  88/*
  89 * computes the checksum of the TCP/UDP pseudo-header
  90 * returns a 16-bit checksum, already complemented
  91 */
  92static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
  93                                        __u32 len, __u8 proto,
  94                                        __wsum sum)
  95{
  96        return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
  97}
  98
  99/*
 100 * this routine is used for miscellaneous IP-like checksums, mainly
 101 * in icmp.c
 102 */
 103static inline __sum16 ip_compute_csum(const void *buf, int len)
 104{
 105         return csum_fold (csum_partial(buf, len, 0));
 106}
 107
 108
 109#define _HAVE_ARCH_IPV6_CSUM
 110static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 111                                          const struct in6_addr *daddr,
 112                                          __u32 len, __u8 proto,
 113                                          __wsum sum)
 114{
 115        unsigned long t0, t1, t2, t3;
 116
 117        len += proto;   /* add 16-bit proto + len */
 118
 119        __asm__ __volatile__ (
 120
 121#if BITS_PER_LONG > 32
 122
 123        /*
 124        ** We can execute two loads and two adds per cycle on PA 8000.
 125        ** But add insn's get serialized waiting for the carry bit.
 126        ** Try to keep 4 registers with "live" values ahead of the ALU.
 127        */
 128
 129"       ldd,ma          8(%1), %4\n"    /* get 1st saddr word */
 130"       ldd,ma          8(%2), %5\n"    /* get 1st daddr word */
 131"       add             %4, %0, %0\n"
 132"       ldd,ma          8(%1), %6\n"    /* 2nd saddr */
 133"       ldd,ma          8(%2), %7\n"    /* 2nd daddr */
 134"       add,dc          %5, %0, %0\n"
 135"       add,dc          %6, %0, %0\n"
 136"       add,dc          %7, %0, %0\n"
 137"       add,dc          %3, %0, %0\n"  /* fold in proto+len | carry bit */
 138"       extrd,u         %0, 31, 32, %4\n"/* copy upper half down */
 139"       depdi           0, 31, 32, %0\n"/* clear upper half */
 140"       add             %4, %0, %0\n"   /* fold into 32-bits */
 141"       addc            0, %0, %0\n"    /* add carry */
 142
 143#else
 144
 145        /*
 146        ** For PA 1.x, the insn order doesn't matter as much.
 147        ** Insn stream is serialized on the carry bit here too.
 148        ** result from the previous operation (eg r0 + x)
 149        */
 150"       ldw,ma          4(%1), %4\n"    /* get 1st saddr word */
 151"       ldw,ma          4(%2), %5\n"    /* get 1st daddr word */
 152"       add             %4, %0, %0\n"
 153"       ldw,ma          4(%1), %6\n"    /* 2nd saddr */
 154"       addc            %5, %0, %0\n"
 155"       ldw,ma          4(%2), %7\n"    /* 2nd daddr */
 156"       addc            %6, %0, %0\n"
 157"       ldw,ma          4(%1), %4\n"    /* 3rd saddr */
 158"       addc            %7, %0, %0\n"
 159"       ldw,ma          4(%2), %5\n"    /* 3rd daddr */
 160"       addc            %4, %0, %0\n"
 161"       ldw,ma          4(%1), %6\n"    /* 4th saddr */
 162"       addc            %5, %0, %0\n"
 163"       ldw,ma          4(%2), %7\n"    /* 4th daddr */
 164"       addc            %6, %0, %0\n"
 165"       addc            %7, %0, %0\n"
 166"       addc            %3, %0, %0\n"   /* fold in proto+len, catch carry */
 167
 168#endif
 169        : "=r" (sum), "=r" (saddr), "=r" (daddr), "=r" (len),
 170          "=r" (t0), "=r" (t1), "=r" (t2), "=r" (t3)
 171        : "0" (sum), "1" (saddr), "2" (daddr), "3" (len)
 172        : "memory");
 173        return csum_fold(sum);
 174}
 175
 176#endif
 177
 178