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, int len); 34 35 #define _HAVE_ARCH_CSUM_AND_COPY 36 /* 37 * Note: when you get a NULL pointer exception here this means someone 38 * passed in an incorrect kernel address to one of these functions. 39 * 40 * If you use these functions directly please don't forget the 41 * access_ok(). 42 */ 43 static inline 44 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len) 45 { 46 return csum_partial_copy_generic(src, dst, len); 47 } 48 49 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 50 static inline 51 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len) 52 { 53 if (!access_ok(src, len)) 54 return 0; 55 return csum_partial_copy_generic((__force const void *)src, dst, len); 56 } 57 58 /* 59 * Fold a partial checksum 60 */ 61 62 static inline __sum16 csum_fold(__wsum sum) 63 { 64 unsigned int __dummy; 65 __asm__("swap.w %0, %1\n\t" 66 "extu.w %0, %0\n\t" 67 "extu.w %1, %1\n\t" 68 "add %1, %0\n\t" 69 "swap.w %0, %1\n\t" 70 "add %1, %0\n\t" 71 "not %0, %0\n\t" 72 : "=r" (sum), "=&r" (__dummy) 73 : "0" (sum) 74 : "t"); 75 return (__force __sum16)sum; 76 } 77 78 /* 79 * This is a version of ip_compute_csum() optimized for IP headers, 80 * which always checksum on 4 octet boundaries. 81 * 82 * i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted 83 * for linux by * Arnt Gulbrandsen. 84 */ 85 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 86 { 87 unsigned int sum, __dummy0, __dummy1; 88 89 __asm__ __volatile__( 90 "mov.l @%1+, %0\n\t" 91 "mov.l @%1+, %3\n\t" 92 "add #-2, %2\n\t" 93 "clrt\n\t" 94 "1:\t" 95 "addc %3, %0\n\t" 96 "movt %4\n\t" 97 "mov.l @%1+, %3\n\t" 98 "dt %2\n\t" 99 "bf/s 1b\n\t" 100 " cmp/eq #1, %4\n\t" 101 "addc %3, %0\n\t" 102 "addc %2, %0" /* Here %2 is 0, add carry-bit */ 103 /* Since the input registers which are loaded with iph and ihl 104 are modified, we must also specify them as outputs, or gcc 105 will assume they contain their original values. */ 106 : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1) 107 : "1" (iph), "2" (ihl) 108 : "t", "memory"); 109 110 return csum_fold(sum); 111 } 112 113 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 114 __u32 len, __u8 proto, 115 __wsum sum) 116 { 117 #ifdef __LITTLE_ENDIAN__ 118 unsigned long len_proto = (proto + len) << 8; 119 #else 120 unsigned long len_proto = proto + len; 121 #endif 122 __asm__("clrt\n\t" 123 "addc %0, %1\n\t" 124 "addc %2, %1\n\t" 125 "addc %3, %1\n\t" 126 "movt %0\n\t" 127 "add %1, %0" 128 : "=r" (sum), "=r" (len_proto) 129 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum) 130 : "t"); 131 132 return sum; 133 } 134 135 /* 136 * computes the checksum of the TCP/UDP pseudo-header 137 * returns a 16-bit checksum, already complemented 138 */ 139 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 140 __u32 len, __u8 proto, 141 __wsum sum) 142 { 143 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 144 } 145 146 /* 147 * this routine is used for miscellaneous IP-like checksums, mainly 148 * in icmp.c 149 */ 150 static inline __sum16 ip_compute_csum(const void *buff, int len) 151 { 152 return csum_fold(csum_partial(buff, len, 0)); 153 } 154 155 #define _HAVE_ARCH_IPV6_CSUM 156 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 157 const struct in6_addr *daddr, 158 __u32 len, __u8 proto, __wsum sum) 159 { 160 unsigned int __dummy; 161 __asm__("clrt\n\t" 162 "mov.l @(0,%2), %1\n\t" 163 "addc %1, %0\n\t" 164 "mov.l @(4,%2), %1\n\t" 165 "addc %1, %0\n\t" 166 "mov.l @(8,%2), %1\n\t" 167 "addc %1, %0\n\t" 168 "mov.l @(12,%2), %1\n\t" 169 "addc %1, %0\n\t" 170 "mov.l @(0,%3), %1\n\t" 171 "addc %1, %0\n\t" 172 "mov.l @(4,%3), %1\n\t" 173 "addc %1, %0\n\t" 174 "mov.l @(8,%3), %1\n\t" 175 "addc %1, %0\n\t" 176 "mov.l @(12,%3), %1\n\t" 177 "addc %1, %0\n\t" 178 "addc %4, %0\n\t" 179 "addc %5, %0\n\t" 180 "movt %1\n\t" 181 "add %1, %0\n" 182 : "=r" (sum), "=&r" (__dummy) 183 : "r" (saddr), "r" (daddr), 184 "r" (htonl(len)), "r" (htonl(proto)), "0" (sum) 185 : "t"); 186 187 return csum_fold(sum); 188 } 189 190 /* 191 * Copy and checksum to user 192 */ 193 #define HAVE_CSUM_COPY_USER 194 static inline __wsum csum_and_copy_to_user(const void *src, 195 void __user *dst, 196 int len) 197 { 198 if (!access_ok(dst, len)) 199 return 0; 200 return csum_partial_copy_generic((__force const void *)src, dst, len); 201 } 202 #endif /* __ASM_SH_CHECKSUM_H */ 203