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,
 34					    int len, __wsum sum,
 35					    int *src_err_ptr, int *dst_err_ptr);
 36
 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,
 46				 int len, __wsum sum)
 47{
 48	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
 49}
 50
 51static inline
 52__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
 53				   int len, __wsum sum, int *err_ptr)
 54{
 55	return csum_partial_copy_generic((__force const void *)src, dst,
 56					len, sum, err_ptr, NULL);
 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	unsigned int sum, __dummy0, __dummy1;
 89
 90	__asm__ __volatile__(
 91		"mov.l	@%1+, %0\n\t"
 92		"mov.l	@%1+, %3\n\t"
 93		"add	#-2, %2\n\t"
 94		"clrt\n\t"
 95		"1:\t"
 96		"addc	%3, %0\n\t"
 97		"movt	%4\n\t"
 98		"mov.l	@%1+, %3\n\t"
 99		"dt	%2\n\t"
100		"bf/s	1b\n\t"
101		" cmp/eq #1, %4\n\t"
102		"addc	%3, %0\n\t"
103		"addc	%2, %0"	    /* Here %2 is 0, add carry-bit */
104	/* Since the input registers which are loaded with iph and ihl
105	   are modified, we must also specify them as outputs, or gcc
106	   will assume they contain their original values. */
107	: "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
108	: "1" (iph), "2" (ihl)
109	: "t", "memory");
110
111	return	csum_fold(sum);
112}
113
114static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
115					__u32 len, __u8 proto,
116					__wsum sum)
117{
118#ifdef __LITTLE_ENDIAN__
119	unsigned long len_proto = (proto + len) << 8;
120#else
121	unsigned long len_proto = proto + len;
122#endif
123	__asm__("clrt\n\t"
124		"addc	%0, %1\n\t"
125		"addc	%2, %1\n\t"
126		"addc	%3, %1\n\t"
127		"movt	%0\n\t"
128		"add	%1, %0"
129		: "=r" (sum), "=r" (len_proto)
130		: "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
131		: "t");
132
133	return sum;
134}
135
136/*
137 * computes the checksum of the TCP/UDP pseudo-header
138 * returns a 16-bit checksum, already complemented
139 */
140static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
141					__u32 len, __u8 proto,
142					__wsum sum)
143{
144	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
145}
146
147/*
148 * this routine is used for miscellaneous IP-like checksums, mainly
149 * in icmp.c
150 */
151static inline __sum16 ip_compute_csum(const void *buff, int len)
152{
153    return csum_fold(csum_partial(buff, len, 0));
154}
155
156#define _HAVE_ARCH_IPV6_CSUM
157static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
158				      const struct in6_addr *daddr,
159				      __u32 len, __u8 proto, __wsum sum)
160{
161	unsigned int __dummy;
162	__asm__("clrt\n\t"
163		"mov.l	@(0,%2), %1\n\t"
164		"addc	%1, %0\n\t"
165		"mov.l	@(4,%2), %1\n\t"
166		"addc	%1, %0\n\t"
167		"mov.l	@(8,%2), %1\n\t"
168		"addc	%1, %0\n\t"
169		"mov.l	@(12,%2), %1\n\t"
170		"addc	%1, %0\n\t"
171		"mov.l	@(0,%3), %1\n\t"
172		"addc	%1, %0\n\t"
173		"mov.l	@(4,%3), %1\n\t"
174		"addc	%1, %0\n\t"
175		"mov.l	@(8,%3), %1\n\t"
176		"addc	%1, %0\n\t"
177		"mov.l	@(12,%3), %1\n\t"
178		"addc	%1, %0\n\t"
179		"addc	%4, %0\n\t"
180		"addc	%5, %0\n\t"
181		"movt	%1\n\t"
182		"add	%1, %0\n"
183		: "=r" (sum), "=&r" (__dummy)
184		: "r" (saddr), "r" (daddr),
185		  "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
186		: "t");
187
188	return csum_fold(sum);
189}
190
191/*
192 *	Copy and checksum to user
193 */
194#define HAVE_CSUM_COPY_USER
195static inline __wsum csum_and_copy_to_user(const void *src,
196					   void __user *dst,
197					   int len, __wsum sum,
198					   int *err_ptr)
199{
200	if (access_ok(dst, len))
201		return csum_partial_copy_generic((__force const void *)src,
202						dst, len, sum, NULL, err_ptr);
203
204	if (len)
205		*err_ptr = -EFAULT;
206
207	return (__force __wsum)-1; /* invalid checksum */
208}
209#endif /* __ASM_SH_CHECKSUM_H */