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 */
23asmlinkage __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
33asmlinkage __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 */
43static 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
50static 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
62static 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 */
85static 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
113static 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 */
139static 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 */
150static 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
156static 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
194static 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