Merge tag 'pci-v3.15-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaa...
[deliverable/linux.git] / arch / s390 / include / asm / checksum.h
CommitLineData
1da177e4 1/*
1da177e4 2 * S390 fast network checksum routines
1da177e4
LT
3 *
4 * S390 version
a53c8fab 5 * Copyright IBM Corp. 1999
1da177e4
LT
6 * Author(s): Ulrich Hild (first version)
7 * Martin Schwidefsky (heavily optimized CKSM version)
8 * D.J. Barrow (third attempt)
9 */
10
a53c8fab
HC
11#ifndef _S390_CHECKSUM_H
12#define _S390_CHECKSUM_H
13
1da177e4
LT
14#include <asm/uaccess.h>
15
16/*
17 * computes the checksum of a memory block at buff, length len,
18 * and adds in "sum" (32-bit)
19 *
20 * returns a 32-bit number suitable for feeding into itself
21 * or csum_tcpudp_magic
22 *
23 * this function must be called with even lengths, except
24 * for the last fragment, which may be odd
25 *
26 * it's best to have buff aligned on a 32-bit boundary
27 */
f994aae1
AV
28static inline __wsum
29csum_partial(const void *buff, int len, __wsum sum)
1da177e4 30{
94c12cc7
MS
31 register unsigned long reg2 asm("2") = (unsigned long) buff;
32 register unsigned long reg3 asm("3") = (unsigned long) len;
1da177e4 33
94c12cc7
MS
34 asm volatile(
35 "0: cksm %0,%1\n" /* do checksum on longs */
36 " jo 0b\n"
37 : "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory");
1da177e4
LT
38 return sum;
39}
40
41/*
42 * the same as csum_partial_copy, but copies from user space.
43 *
44 * here even more important to align src and dst on a 32-bit (or even
45 * better 64-bit) boundary
46 *
d72d2bb5 47 * Copy from userspace and compute checksum.
1da177e4 48 */
f994aae1
AV
49static inline __wsum
50csum_partial_copy_from_user(const void __user *src, void *dst,
51 int len, __wsum sum,
1da177e4
LT
52 int *err_ptr)
53{
d72d2bb5 54 if (unlikely(copy_from_user(dst, src, len)))
1da177e4 55 *err_ptr = -EFAULT;
1da177e4
LT
56 return csum_partial(dst, len, sum);
57}
58
59
f994aae1
AV
60static inline __wsum
61csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
1da177e4
LT
62{
63 memcpy(dst,src,len);
94c12cc7 64 return csum_partial(dst, len, sum);
1da177e4
LT
65}
66
67/*
68 * Fold a partial checksum without adding pseudo headers
69 */
f994aae1 70static inline __sum16 csum_fold(__wsum sum)
1da177e4 71{
04efc3be 72 u32 csum = (__force u32) sum;
1da177e4 73
04efc3be
HC
74 csum += (csum >> 16) + (csum << 16);
75 csum >>= 16;
76 return (__force __sum16) ~csum;
1da177e4
LT
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 */
f994aae1 84static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
1da177e4 85{
94c12cc7 86 return csum_fold(csum_partial(iph, ihl*4, 0));
1da177e4
LT
87}
88
89/*
90 * computes the checksum of the TCP/UDP pseudo-header
91 * returns a 32-bit checksum
92 */
f994aae1
AV
93static inline __wsum
94csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
1da177e4 95 unsigned short len, unsigned short proto,
f994aae1 96 __wsum sum)
1da177e4 97{
afbc1e99
HC
98 __u32 csum = (__force __u32)sum;
99
100 csum += (__force __u32)saddr;
101 if (csum < (__force __u32)saddr)
102 csum++;
103
104 csum += (__force __u32)daddr;
105 if (csum < (__force __u32)daddr)
106 csum++;
107
108 csum += len + proto;
109 if (csum < len + proto)
110 csum++;
111
112 return (__force __wsum)csum;
1da177e4
LT
113}
114
115/*
116 * computes the checksum of the TCP/UDP pseudo-header
117 * returns a 16-bit checksum, already complemented
118 */
119
f994aae1
AV
120static inline __sum16
121csum_tcpudp_magic(__be32 saddr, __be32 daddr,
1da177e4 122 unsigned short len, unsigned short proto,
f994aae1 123 __wsum sum)
1da177e4
LT
124{
125 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
126}
127
128/*
129 * this routine is used for miscellaneous IP-like checksums, mainly
130 * in icmp.c
131 */
132
f994aae1 133static inline __sum16 ip_compute_csum(const void *buff, int len)
1da177e4
LT
134{
135 return csum_fold(csum_partial(buff, len, 0));
136}
137
138#endif /* _S390_CHECKSUM_H */
139
140
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