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 */
34static 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 x: (__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}
74EXPORT_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 */
85unsigned 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

source code of linux/arch/hexagon/lib/checksum.c