1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_CHECKSUM_64_H
3#define _ASM_X86_CHECKSUM_64_H
4
5/*
6 * Checksums for x86-64
7 * Copyright 2002 by Andi Kleen, SuSE Labs
8 * with some code from asm-x86/checksum.h
9 */
10
11#include <linux/compiler.h>
12#include <linux/uaccess.h>
13#include <asm/byteorder.h>
14
15/**
16 * csum_fold - Fold and invert a 32bit checksum.
17 * sum: 32bit unfolded sum
18 *
19 * Fold a 32bit running checksum to 16bit and invert it. This is usually
20 * the last step before putting a checksum into a packet.
21 * Make sure not to mix with 64bit checksums.
22 */
23static inline __sum16 csum_fold(__wsum sum)
24{
25 asm(" addl %1,%0\n"
26 " adcl $0xffff,%0"
27 : "=r" (sum)
28 : "r" ((__force u32)sum << 16),
29 "0" ((__force u32)sum & 0xffff0000));
30 return (__force __sum16)(~(__force u32)sum >> 16);
31}
32
33/*
34 * This is a version of ip_compute_csum() optimized for IP headers,
35 * which always checksum on 4 octet boundaries.
36 *
37 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
38 * Arnt Gulbrandsen.
39 */
40
41/**
42 * ip_fast_csum - Compute the IPv4 header checksum efficiently.
43 * iph: ipv4 header
44 * ihl: length of header / 4
45 */
46static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
47{
48 unsigned int sum;
49
50 asm(" movl (%1), %0\n"
51 " subl $4, %2\n"
52 " jbe 2f\n"
53 " addl 4(%1), %0\n"
54 " adcl 8(%1), %0\n"
55 " adcl 12(%1), %0\n"
56 "1: adcl 16(%1), %0\n"
57 " lea 4(%1), %1\n"
58 " decl %2\n"
59 " jne 1b\n"
60 " adcl $0, %0\n"
61 " movl %0, %2\n"
62 " shrl $16, %0\n"
63 " addw %w2, %w0\n"
64 " adcl $0, %0\n"
65 " notl %0\n"
66 "2:"
67 /* Since the input registers which are loaded with iph and ihl
68 are modified, we must also specify them as outputs, or gcc
69 will assume they contain their original values. */
70 : "=r" (sum), "=r" (iph), "=r" (ihl)
71 : "1" (iph), "2" (ihl)
72 : "memory");
73 return (__force __sum16)sum;
74}
75
76/**
77 * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
78 * @saddr: source address
79 * @daddr: destination address
80 * @len: length of packet
81 * @proto: ip protocol of packet
82 * @sum: initial sum to be added in (32bit unfolded)
83 *
84 * Returns the pseudo header checksum the input data. Result is
85 * 32bit unfolded.
86 */
87static inline __wsum
88csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
89 __u8 proto, __wsum sum)
90{
91 asm(" addl %1, %0\n"
92 " adcl %2, %0\n"
93 " adcl %3, %0\n"
94 " adcl $0, %0\n"
95 : "=r" (sum)
96 : "g" (daddr), "g" (saddr),
97 "g" ((len + proto)<<8), "0" (sum));
98 return sum;
99}
100
101
102/**
103 * csum_tcpup_magic - Compute an IPv4 pseudo header checksum.
104 * @saddr: source address
105 * @daddr: destination address
106 * @len: length of packet
107 * @proto: ip protocol of packet
108 * @sum: initial sum to be added in (32bit unfolded)
109 *
110 * Returns the 16bit pseudo header checksum the input data already
111 * complemented and ready to be filled in.
112 */
113static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
114 __u32 len, __u8 proto,
115 __wsum sum)
116{
117 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
118}
119
120/**
121 * csum_partial - Compute an internet checksum.
122 * @buff: buffer to be checksummed
123 * @len: length of buffer.
124 * @sum: initial sum to be added in (32bit unfolded)
125 *
126 * Returns the 32bit unfolded internet checksum of the buffer.
127 * Before filling it in it needs to be csum_fold()'ed.
128 * buff should be aligned to a 64bit boundary if possible.
129 */
130extern __wsum csum_partial(const void *buff, int len, __wsum sum);
131
132#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
133#define HAVE_CSUM_COPY_USER 1
134
135
136/* Do not call this directly. Use the wrappers below */
137extern __visible __wsum csum_partial_copy_generic(const void *src, const void *dst,
138 int len, __wsum sum,
139 int *src_err_ptr, int *dst_err_ptr);
140
141
142extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
143 int len, __wsum isum, int *errp);
144extern __wsum csum_partial_copy_to_user(const void *src, void __user *dst,
145 int len, __wsum isum, int *errp);
146extern __wsum csum_partial_copy_nocheck(const void *src, void *dst,
147 int len, __wsum sum);
148
149/* Old names. To be removed. */
150#define csum_and_copy_to_user csum_partial_copy_to_user
151#define csum_and_copy_from_user csum_partial_copy_from_user
152
153/**
154 * ip_compute_csum - Compute an 16bit IP checksum.
155 * @buff: buffer address.
156 * @len: length of buffer.
157 *
158 * Returns the 16bit folded/inverted checksum of the passed buffer.
159 * Ready to fill in.
160 */
161extern __sum16 ip_compute_csum(const void *buff, int len);
162
163/**
164 * csum_ipv6_magic - Compute checksum of an IPv6 pseudo header.
165 * @saddr: source address
166 * @daddr: destination address
167 * @len: length of packet
168 * @proto: protocol of packet
169 * @sum: initial sum (32bit unfolded) to be added in
170 *
171 * Computes an IPv6 pseudo header checksum. This sum is added the checksum
172 * into UDP/TCP packets and contains some link layer information.
173 * Returns the unfolded 32bit checksum.
174 */
175
176struct in6_addr;
177
178#define _HAVE_ARCH_IPV6_CSUM 1
179extern __sum16
180csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
181 __u32 len, __u8 proto, __wsum sum);
182
183static inline unsigned add32_with_carry(unsigned a, unsigned b)
184{
185 asm("addl %2,%0\n\t"
186 "adcl $0,%0"
187 : "=r" (a)
188 : "0" (a), "rm" (b));
189 return a;
190}
191
192#define HAVE_ARCH_CSUM_ADD
193static inline __wsum csum_add(__wsum csum, __wsum addend)
194{
195 return (__force __wsum)add32_with_carry((__force unsigned)csum,
196 (__force unsigned)addend);
197}
198
199#endif /* _ASM_X86_CHECKSUM_64_H */
200