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 */ 210