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#include <linux/uaccess.h>
11
12/*
13 * computes the checksum of a memory block at buff, length len,
14 * and adds in "sum" (32-bit)
15 *
16 * returns a 32-bit number suitable for feeding into itself
17 * or csum_tcpudp_magic
18 *
19 * this function must be called with even lengths, except
20 * for the last fragment, which may be odd
21 *
22 * it's best to have buff aligned on a 32-bit boundary
23 */
24asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
25
26/*
27 * the same as csum_partial, but copies from src while it
28 * checksums, and handles user-space pointer exceptions correctly, when needed.
29 *
30 * here even more important to align src and dst on a 32-bit (or even
31 * better 64-bit) boundary
32 */
33
34asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
35
36#define _HAVE_ARCH_CSUM_AND_COPY
37/*
38 *	Note: when you get a NULL pointer exception here this means someone
39 *	passed in an incorrect kernel address to one of these functions.
40 *
41 *	If you use these functions directly please don't forget the
42 *	access_ok().
43 */
44static inline
45__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
46{
47	return csum_partial_copy_generic(src, dst, len);
48}
49
50#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
51static inline
52__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
53{
54	if (!access_ok(src, len))
55		return 0;
56	return csum_partial_copy_generic((__force const void *)src, dst, len);
57}
58
59/*
60 *	Fold a partial checksum
61 */
62
63static inline __sum16 csum_fold(__wsum sum)
64{
65	unsigned int __dummy;
66	__asm__("swap.w %0, %1\n\t"
67		"extu.w	%0, %0\n\t"
68		"extu.w	%1, %1\n\t"
69		"add	%1, %0\n\t"
70		"swap.w	%0, %1\n\t"
71		"add	%1, %0\n\t"
72		"not	%0, %0\n\t"
73		: "=r" (sum), "=&r" (__dummy)
74		: "0" (sum)
75		: "t");
76	return (__force __sum16)sum;
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 *      i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
84 *      for linux by * Arnt Gulbrandsen.
85 */
86static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
87{
88	__wsum sum;
89	unsigned int __dummy0, __dummy1;
90
91	__asm__ __volatile__(
92		"mov.l	@%1+, %0\n\t"
93		"mov.l	@%1+, %3\n\t"
94		"add	#-2, %2\n\t"
95		"clrt\n\t"
96		"1:\t"
97		"addc	%3, %0\n\t"
98		"movt	%4\n\t"
99		"mov.l	@%1+, %3\n\t"
100		"dt	%2\n\t"
101		"bf/s	1b\n\t"
102		" cmp/eq #1, %4\n\t"
103		"addc	%3, %0\n\t"
104		"addc	%2, %0"	    /* Here %2 is 0, add carry-bit */
105	/* Since the input registers which are loaded with iph and ihl
106	   are modified, we must also specify them as outputs, or gcc
107	   will assume they contain their original values. */
108	: "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
109	: "1" (iph), "2" (ihl)
110	: "t", "memory");
111
112	return	csum_fold(sum);
113}
114
115static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
116					__u32 len, __u8 proto,
117					__wsum sum)
118{
119#ifdef __LITTLE_ENDIAN__
120	unsigned long len_proto = (proto + len) << 8;
121#else
122	unsigned long len_proto = proto + len;
123#endif
124	__asm__("clrt\n\t"
125		"addc	%0, %1\n\t"
126		"addc	%2, %1\n\t"
127		"addc	%3, %1\n\t"
128		"movt	%0\n\t"
129		"add	%1, %0"
130		: "=r" (sum), "=r" (len_proto)
131		: "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
132		: "t");
133
134	return sum;
135}
136
137/*
138 * computes the checksum of the TCP/UDP pseudo-header
139 * returns a 16-bit checksum, already complemented
140 */
141static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
142					__u32 len, __u8 proto,
143					__wsum sum)
144{
145	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
146}
147
148/*
149 * this routine is used for miscellaneous IP-like checksums, mainly
150 * in icmp.c
151 */
152static inline __sum16 ip_compute_csum(const void *buff, int len)
153{
154    return csum_fold(csum_partial(buff, len, 0));
155}
156
157#define _HAVE_ARCH_IPV6_CSUM
158static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
159				      const struct in6_addr *daddr,
160				      __u32 len, __u8 proto, __wsum sum)
161{
162	unsigned int __dummy;
163	__asm__("clrt\n\t"
164		"mov.l	@(0,%2), %1\n\t"
165		"addc	%1, %0\n\t"
166		"mov.l	@(4,%2), %1\n\t"
167		"addc	%1, %0\n\t"
168		"mov.l	@(8,%2), %1\n\t"
169		"addc	%1, %0\n\t"
170		"mov.l	@(12,%2), %1\n\t"
171		"addc	%1, %0\n\t"
172		"mov.l	@(0,%3), %1\n\t"
173		"addc	%1, %0\n\t"
174		"mov.l	@(4,%3), %1\n\t"
175		"addc	%1, %0\n\t"
176		"mov.l	@(8,%3), %1\n\t"
177		"addc	%1, %0\n\t"
178		"mov.l	@(12,%3), %1\n\t"
179		"addc	%1, %0\n\t"
180		"addc	%4, %0\n\t"
181		"addc	%5, %0\n\t"
182		"movt	%1\n\t"
183		"add	%1, %0\n"
184		: "=r" (sum), "=&r" (__dummy)
185		: "r" (saddr), "r" (daddr),
186		  "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
187		: "t");
188
189	return csum_fold(sum);
190}
191
192/*
193 *	Copy and checksum to user
194 */
195#define HAVE_CSUM_COPY_USER
196static inline __wsum csum_and_copy_to_user(const void *src,
197					   void __user *dst,
198					   int len)
199{
200	if (!access_ok(dst, len))
201		return 0;
202	return csum_partial_copy_generic(src, (__force void *)dst, len);
203}
204#endif /* __ASM_SH_CHECKSUM_H */
205