arch/hexagon/lib/checksum.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Checksum functions for Hexagon
   4  *
   5  * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   6  */
   7
   8 /*  This was derived from arch/alpha/lib/checksum.c  */
   9
  10
  11 #include <linux/module.h>
  12 #include <linux/string.h>
  13
  14 #include <asm/byteorder.h>
  15 #include <net/checksum.h>
  16 #include <linux/uaccess.h>
  17 #include <asm/intrinsics.h>
  18
  19
  20 /*  Vector value operations  */
  21 #define SIGN(x, y)      ((0x8000ULL*x)<<y)
  22 #define CARRY(x, y)     ((0x0002ULL*x)<<y)
  23 #define SELECT(x, y)    ((0x0001ULL*x)<<y)
  24
  25 #define VR_NEGATE(a, b, c, d)   (SIGN(a, 48) + SIGN(b, 32) + SIGN(c, 16) \
  26         + SIGN(d, 0))
  27 #define VR_CARRY(a, b, c, d)    (CARRY(a, 48) + CARRY(b, 32) + CARRY(c, 16) \
  28         + CARRY(d, 0))
  29 #define VR_SELECT(a, b, c, d)   (SELECT(a, 48) + SELECT(b, 32) + SELECT(c, 16) \
  30         + SELECT(d, 0))
  31
  32
  33 /* optimized HEXAGON V3 intrinsic version */
  34 static inline unsigned short from64to16(u64 x)
  35 {
  36         u64 sum;
  37
  38         sum = HEXAGON_P_vrmpyh_PP(x^VR_NEGATE(1, 1, 1, 1),
  39                              VR_SELECT(1, 1, 1, 1));
  40         sum += VR_CARRY(0, 0, 1, 0);
  41         sum = HEXAGON_P_vrmpyh_PP(sum, VR_SELECT(0, 0, 1, 1));
  42
  43         return 0xFFFF & sum;
  44 }
  45
  46 /*
  47  * computes the checksum of the TCP/UDP pseudo-header
  48  * returns a 16-bit checksum, already complemented.
  49  */
  50 __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
  51                           __u32 len, __u8 proto, __wsum sum)
  52 {
  53         return (__force __sum16)~from64to16(
  54                 (__force u64)saddr + (__force u64)daddr +
  55                 (__force u64)sum + ((len + proto) << 8));
  56 }
  57
  58 __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  59                           __u32 len, __u8 proto, __wsum sum)
  60 {
  61         u64 result;
  62
  63         result = (__force u64)saddr + (__force u64)daddr +
  64                  (__force u64)sum + ((len + proto) << 8);
  65
  66         /* Fold down to 32-bits so we don't lose in the typedef-less
  67            network stack.  */
  68         /* 64 to 33 */
  69         result = (result & 0xffffffffUL) + (result >> 32);
  70         /* 33 to 32 */
  71         result = (result & 0xffffffffUL) + (result >> 32);
  72         return (__force __wsum)result;
  73 }
  74 EXPORT_SYMBOL(csum_tcpudp_nofold);
  75
  76 /*
  77  * Do a 64-bit checksum on an arbitrary memory area..
  78  *
  79  * This isn't a great routine, but it's not _horrible_ either. The
  80  * inner loop could be unrolled a bit further, and there are better
  81  * ways to do the carry, but this is reasonable.
  82  */
  83
  84 /* optimized HEXAGON intrinsic version, with over read fixed */
  85 unsigned int do_csum(const void *voidptr, int len)
  86 {
  87         u64 sum0, sum1, x0, x1, *ptr8_o, *ptr8_e, *ptr8;
  88         int i, start, mid, end, mask;
  89         const char *ptr = voidptr;
  90         unsigned short *ptr2;
  91         unsigned int *ptr4;
  92
  93         if (len <= 0)
  94                 return 0;
  95
  96         start = 0xF & (16-(((int) ptr) & 0xF)) ;
  97         mask  = 0x7fffffffUL >> HEXAGON_R_cl0_R(len);
  98         start = start & mask ;
  99
 100         mid = len - start;
 101         end = mid & 0xF;
 102         mid = mid>>4;
 103         sum0 = mid << 18;
 104         sum1 = 0;
 105
 106         if (start & 1)
 107                 sum0 += (u64) (ptr[0] << 8);
 108         ptr2 = (unsigned short *) &ptr[start & 1];
 109         if (start & 2)
 110                 sum1 += (u64) ptr2[0];
 111         ptr4 = (unsigned int *) &ptr[start & 3];
 112         if (start & 4) {
 113                 sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
 114                         VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
 115                         VR_SELECT(0, 0, 1, 1));
 116                 sum0 += VR_SELECT(0, 0, 1, 0);
 117         }
 118         ptr8 = (u64 *) &ptr[start & 7];
 119         if (start & 8) {
 120                 sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
 121                         VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
 122                         VR_SELECT(1, 1, 1, 1));
 123                 sum1 += VR_CARRY(0, 0, 1, 0);
 124         }
 125         ptr8_o = (u64 *) (ptr + start);
 126         ptr8_e = (u64 *) (ptr + start + 8);
 127
 128         if (mid) {
 129                 x0 = *ptr8_e; ptr8_e += 2;
 130                 x1 = *ptr8_o; ptr8_o += 2;
 131                 if (mid > 1)
 132                         for (i = 0; i < mid-1; i++) {
 133                                 sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
 134                                         x0^VR_NEGATE(1, 1, 1, 1),
 135                                         VR_SELECT(1, 1, 1, 1));
 136                                 sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
 137                                         x1^VR_NEGATE(1, 1, 1, 1),
 138                                         VR_SELECT(1, 1, 1, 1));
 139                                 x0 = *ptr8_e; ptr8_e += 2;
 140                                 x1 = *ptr8_o; ptr8_o += 2;
 141                         }
 142                 sum0 = HEXAGON_P_vrmpyhacc_PP(sum0, x0^VR_NEGATE(1, 1, 1, 1),
 143                         VR_SELECT(1, 1, 1, 1));
 144                 sum1 = HEXAGON_P_vrmpyhacc_PP(sum1, x1^VR_NEGATE(1, 1, 1, 1),
 145                         VR_SELECT(1, 1, 1, 1));
 146         }
 147
 148         ptr4 = (unsigned int *) &ptr[start + (mid * 16) + (end & 8)];
 149         if (end & 4) {
 150                 sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
 151                         VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
 152                         VR_SELECT(0, 0, 1, 1));
 153                 sum1 += VR_SELECT(0, 0, 1, 0);
 154         }
 155         ptr2 = (unsigned short *) &ptr[start + (mid * 16) + (end & 12)];
 156         if (end & 2)
 157                 sum0 += (u64) ptr2[0];
 158
 159         if (end & 1)
 160                 sum1 += (u64) ptr[start + (mid * 16) + (end & 14)];
 161
 162         ptr8 = (u64 *) &ptr[start + (mid * 16)];
 163         if (end & 8) {
 164                 sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
 165                         VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
 166                         VR_SELECT(1, 1, 1, 1));
 167                 sum0 += VR_CARRY(0, 0, 1, 0);
 168         }
 169         sum0 = HEXAGON_P_vrmpyh_PP((sum0+sum1)^VR_NEGATE(0, 0, 0, 1),
 170                 VR_SELECT(0, 0, 1, 1));
 171         sum0 += VR_NEGATE(0, 0, 0, 1);
 172         sum0 = HEXAGON_P_vrmpyh_PP(sum0, VR_SELECT(0, 0, 1, 1));
 173
 174         if (start & 1)
 175                 sum0 = (sum0 << 8) | (0xFF & (sum0 >> 8));
 176
 177         return 0xFFFF & sum0;
 178 }
 179
 180 /*
 181  * copy from ds while checksumming, otherwise like csum_partial
 182  */
 183 __wsum
 184 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
 185 {
 186         memcpy(dst, src, len);
 187         return csum_partial(dst, len, sum);
 188 }
 189 EXPORT_SYMBOL(csum_partial_copy_nocheck);