tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#ifndef _ASM_POWERPC_CHECKSUM_H
2#define _ASM_POWERPC_CHECKSUM_H
3#ifdef __KERNEL__
4
5/*
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12/*
13 * This is a version of ip_compute_csum() optimized for IP headers,
14 * which always checksum on 4 octet boundaries. ihl is the number
15 * of 32-bit words and is always >= 5.
16 */
17extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
18
19/*
20 * computes the checksum of the TCP/UDP pseudo-header
21 * returns a 16-bit checksum, already complemented
22 */
23extern __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
24 unsigned short len,
25 unsigned short proto,
26 __wsum sum);
27
28/*
29 * computes the checksum of a memory block at buff, length len,
30 * and adds in "sum" (32-bit)
31 *
32 * returns a 32-bit number suitable for feeding into itself
33 * or csum_tcpudp_magic
34 *
35 * this function must be called with even lengths, except
36 * for the last fragment, which may be odd
37 *
38 * it's best to have buff aligned on a 32-bit boundary
39 */
40extern __wsum csum_partial(const void *buff, int len, __wsum sum);
41
42/*
43 * Computes the checksum of a memory block at src, length len,
44 * and adds in "sum" (32-bit), while copying the block to dst.
45 * If an access exception occurs on src or dst, it stores -EFAULT
46 * to *src_err or *dst_err respectively (if that pointer is not
47 * NULL), and, for an error on src, zeroes the rest of dst.
48 *
49 * Like csum_partial, this must be called with even lengths,
50 * except for the last fragment.
51 */
52extern __wsum csum_partial_copy_generic(const void *src, void *dst,
53 int len, __wsum sum,
54 int *src_err, int *dst_err);
55
56#ifdef __powerpc64__
57#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
58extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
59 int len, __wsum sum, int *err_ptr);
60#define HAVE_CSUM_COPY_USER
61extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
62 int len, __wsum sum, int *err_ptr);
63#else
64/*
65 * the same as csum_partial, but copies from src to dst while it
66 * checksums.
67 */
68#define csum_partial_copy_from_user(src, dst, len, sum, errp) \
69 csum_partial_copy_generic((__force const void *)(src), (dst), (len), (sum), (errp), NULL)
70#endif
71
72#define csum_partial_copy_nocheck(src, dst, len, sum) \
73 csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
74
75
76/*
77 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
78 * 1's complement 16-bit checksum.
79 */
80static inline __sum16 csum_fold(__wsum sum)
81{
82 unsigned int tmp;
83
84 /* swap the two 16-bit halves of sum */
85 __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
86 /* if there is a carry from adding the two 16-bit halves,
87 it will carry from the lower half into the upper half,
88 giving us the correct sum in the upper half. */
89 return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
90}
91
92/*
93 * this routine is used for miscellaneous IP-like checksums, mainly
94 * in icmp.c
95 */
96static inline __sum16 ip_compute_csum(const void *buff, int len)
97{
98 return csum_fold(csum_partial(buff, len, 0));
99}
100
101static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
102 unsigned short len,
103 unsigned short proto,
104 __wsum sum)
105{
106#ifdef __powerpc64__
107 unsigned long s = (__force u32)sum;
108
109 s += (__force u32)saddr;
110 s += (__force u32)daddr;
111 s += proto + len;
112 s += (s >> 32);
113 return (__force __wsum) s;
114#else
115 __asm__("\n\
116 addc %0,%0,%1 \n\
117 adde %0,%0,%2 \n\
118 adde %0,%0,%3 \n\
119 addze %0,%0 \n\
120 "
121 : "=r" (sum)
122 : "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
123 return sum;
124#endif
125}
126#endif /* __KERNEL__ */
127#endif