1 #ifndef _S390_CHECKSUM_H 2 #define _S390_CHECKSUM_H 3 4 /* 5 * include/asm-s390/checksum.h 6 * S390 fast network checksum routines 7 * see also arch/S390/lib/checksum.c 8 * 9 * S390 version 10 * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation 11 * Author(s): Ulrich Hild (first version) 12 * Martin Schwidefsky (heavily optimized CKSM version) 13 * D.J. Barrow (third attempt) 14 */ 15 16 #include <asm/uaccess.h> 17 18 /* 19 * computes the checksum of a memory block at buff, length len, 20 * and adds in "sum" (32-bit) 21 * 22 * returns a 32-bit number suitable for feeding into itself 23 * or csum_tcpudp_magic 24 * 25 * this function must be called with even lengths, except 26 * for the last fragment, which may be odd 27 * 28 * it's best to have buff aligned on a 32-bit boundary 29 */ 30 static inline __wsum 31 csum_partial(const void *buff, int len, __wsum sum) 32 { 33 register unsigned long reg2 asm("2") = (unsigned long) buff; 34 register unsigned long reg3 asm("3") = (unsigned long) len; 35 36 asm volatile( 37 "0: cksm %0,%1\n" /* do checksum on longs */ 38 " jo 0b\n" 39 : "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory"); 40 return sum; 41 } 42 43 /* 44 * the same as csum_partial_copy, but copies from user space. 45 * 46 * here even more important to align src and dst on a 32-bit (or even 47 * better 64-bit) boundary 48 * 49 * Copy from userspace and compute checksum. If we catch an exception 50 * then zero the rest of the buffer. 51 */ 52 static inline __wsum 53 csum_partial_copy_from_user(const void __user *src, void *dst, 54 int len, __wsum sum, 55 int *err_ptr) 56 { 57 int missing; 58 59 missing = copy_from_user(dst, src, len); 60 if (missing) { 61 memset(dst + len - missing, 0, missing); 62 *err_ptr = -EFAULT; 63 } 64 65 return csum_partial(dst, len, sum); 66 } 67 68 69 static inline __wsum 70 csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum) 71 { 72 memcpy(dst,src,len); 73 return csum_partial(dst, len, sum); 74 } 75 76 /* 77 * Fold a partial checksum without adding pseudo headers 78 */ 79 static inline __sum16 csum_fold(__wsum sum) 80 { 81 #ifndef __s390x__ 82 register_pair rp; 83 84 asm volatile( 85 " slr %N1,%N1\n" /* %0 = H L */ 86 " lr %1,%0\n" /* %0 = H L, %1 = H L 0 0 */ 87 " srdl %1,16\n" /* %0 = H L, %1 = 0 H L 0 */ 88 " alr %1,%N1\n" /* %0 = H L, %1 = L H L 0 */ 89 " alr %0,%1\n" /* %0 = H+L+C L+H */ 90 " srl %0,16\n" /* %0 = H+L+C */ 91 : "+&d" (sum), "=d" (rp) : : "cc"); 92 #else /* __s390x__ */ 93 asm volatile( 94 " sr 3,3\n" /* %0 = H*65536 + L */ 95 " lr 2,%0\n" /* %0 = H L, 2/3 = H L / 0 0 */ 96 " srdl 2,16\n" /* %0 = H L, 2/3 = 0 H / L 0 */ 97 " alr 2,3\n" /* %0 = H L, 2/3 = L H / L 0 */ 98 " alr %0,2\n" /* %0 = H+L+C L+H */ 99 " srl %0,16\n" /* %0 = H+L+C */ 100 : "+&d" (sum) : : "cc", "2", "3"); 101 #endif /* __s390x__ */ 102 return (__force __sum16) ~sum; 103 } 104 105 /* 106 * This is a version of ip_compute_csum() optimized for IP headers, 107 * which always checksum on 4 octet boundaries. 108 * 109 */ 110 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 111 { 112 return csum_fold(csum_partial(iph, ihl*4, 0)); 113 } 114 115 /* 116 * computes the checksum of the TCP/UDP pseudo-header 117 * returns a 32-bit checksum 118 */ 119 static inline __wsum 120 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 121 unsigned short len, unsigned short proto, 122 __wsum sum) 123 { 124 __u32 csum = (__force __u32)sum; 125 126 csum += (__force __u32)saddr; 127 if (csum < (__force __u32)saddr) 128 csum++; 129 130 csum += (__force __u32)daddr; 131 if (csum < (__force __u32)daddr) 132 csum++; 133 134 csum += len + proto; 135 if (csum < len + proto) 136 csum++; 137 138 return (__force __wsum)csum; 139 } 140 141 /* 142 * computes the checksum of the TCP/UDP pseudo-header 143 * returns a 16-bit checksum, already complemented 144 */ 145 146 static inline __sum16 147 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 148 unsigned short len, unsigned short proto, 149 __wsum sum) 150 { 151 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); 152 } 153 154 /* 155 * this routine is used for miscellaneous IP-like checksums, mainly 156 * in icmp.c 157 */ 158 159 static inline __sum16 ip_compute_csum(const void *buff, int len) 160 { 161 return csum_fold(csum_partial(buff, len, 0)); 162 } 163 164 #endif /* _S390_CHECKSUM_H */ 165 166 167