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/arch/xtensa/include/asm/checksum.h

https://bitbucket.org/ndreys/linux-sunxi
C++ Header | 252 lines | 175 code | 22 blank | 55 comment | 2 complexity | bf5d732b9057163dbc037108faf45c1a MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1/*
  2 * include/asm-xtensa/checksum.h
  3 *
  4 * This file is subject to the terms and conditions of the GNU General Public
  5 * License.  See the file "COPYING" in the main directory of this archive
  6 * for more details.
  7 *
  8 * Copyright (C) 2001 - 2005 Tensilica Inc.
  9 */
 10
 11#ifndef _XTENSA_CHECKSUM_H
 12#define _XTENSA_CHECKSUM_H
 13
 14#include <linux/in6.h>
 15#include <variant/core.h>
 16
 17/*
 18 * computes the checksum of a memory block at buff, length len,
 19 * and adds in "sum" (32-bit)
 20 *
 21 * returns a 32-bit number suitable for feeding into itself
 22 * or csum_tcpudp_magic
 23 *
 24 * this function must be called with even lengths, except
 25 * for the last fragment, which may be odd
 26 *
 27 * it's best to have buff aligned on a 32-bit boundary
 28 */
 29asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
 30
 31/*
 32 * the same as csum_partial, but copies from src while it
 33 * checksums, and handles user-space pointer exceptions correctly, when needed.
 34 *
 35 * here even more important to align src and dst on a 32-bit (or even
 36 * better 64-bit) boundary
 37 */
 38
 39asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len, __wsum sum,
 40						   int *src_err_ptr, int *dst_err_ptr);
 41
 42/*
 43 *	Note: when you get a NULL pointer exception here this means someone
 44 *	passed in an incorrect kernel address to one of these functions.
 45 *
 46 *	If you use these functions directly please don't forget the access_ok().
 47 */
 48static inline
 49__wsum csum_partial_copy_nocheck(const void *src, void *dst,
 50					int len, __wsum sum)
 51{
 52	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
 53}
 54
 55static inline
 56__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
 57						int len, __wsum sum, int *err_ptr)
 58{
 59	return csum_partial_copy_generic((__force const void *)src, dst,
 60					len, sum, err_ptr, NULL);
 61}
 62
 63/*
 64 *	Fold a partial checksum
 65 */
 66
 67static __inline__ __sum16 csum_fold(__wsum sum)
 68{
 69	unsigned int __dummy;
 70	__asm__("extui	%1, %0, 16, 16\n\t"
 71		"extui	%0 ,%0, 0, 16\n\t"
 72		"add	%0, %0, %1\n\t"
 73		"slli	%1, %0, 16\n\t"
 74		"add	%0, %0, %1\n\t"
 75		"extui	%0, %0, 16, 16\n\t"
 76		"neg	%0, %0\n\t"
 77		"addi	%0, %0, -1\n\t"
 78		"extui	%0, %0, 0, 16\n\t"
 79		: "=r" (sum), "=&r" (__dummy)
 80		: "0" (sum));
 81	return (__force __sum16)sum;
 82}
 83
 84/*
 85 *	This is a version of ip_compute_csum() optimized for IP headers,
 86 *	which always checksum on 4 octet boundaries.
 87 */
 88static __inline__ __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
 89{
 90	unsigned int sum, tmp, endaddr;
 91
 92	__asm__ __volatile__(
 93		"sub		%0, %0, %0\n\t"
 94#if XCHAL_HAVE_LOOPS
 95		"loopgtz	%2, 2f\n\t"
 96#else
 97		"beqz		%2, 2f\n\t"
 98		"slli		%4, %2, 2\n\t"
 99		"add		%4, %4, %1\n\t"
100		"0:\t"
101#endif
102		"l32i		%3, %1, 0\n\t"
103		"add		%0, %0, %3\n\t"
104		"bgeu		%0, %3, 1f\n\t"
105		"addi		%0, %0, 1\n\t"
106		"1:\t"
107		"addi		%1, %1, 4\n\t"
108#if !XCHAL_HAVE_LOOPS
109		"blt		%1, %4, 0b\n\t"
110#endif
111		"2:\t"
112	/* Since the input registers which are loaded with iph and ihl
113	   are modified, we must also specify them as outputs, or gcc
114	   will assume they contain their original values. */
115		: "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (tmp), "=&r" (endaddr)
116		: "1" (iph), "2" (ihl)
117		: "memory");
118
119	return	csum_fold(sum);
120}
121
122static __inline__ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
123						   unsigned short len,
124						   unsigned short proto,
125						   __wsum sum)
126{
127
128#ifdef __XTENSA_EL__
129	unsigned long len_proto = (len + proto) << 8;
130#elif defined(__XTENSA_EB__)
131	unsigned long len_proto = len + proto;
132#else
133# error processor byte order undefined!
134#endif
135	__asm__("add	%0, %0, %1\n\t"
136		"bgeu	%0, %1, 1f\n\t"
137		"addi	%0, %0, 1\n\t"
138		"1:\t"
139		"add	%0, %0, %2\n\t"
140		"bgeu	%0, %2, 1f\n\t"
141		"addi	%0, %0, 1\n\t"
142		"1:\t"
143		"add	%0, %0, %3\n\t"
144		"bgeu	%0, %3, 1f\n\t"
145		"addi	%0, %0, 1\n\t"
146		"1:\t"
147		: "=r" (sum), "=r" (len_proto)
148		: "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum));
149	return sum;
150}
151
152/*
153 * computes the checksum of the TCP/UDP pseudo-header
154 * returns a 16-bit checksum, already complemented
155 */
156static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
157						       unsigned short len,
158						       unsigned short proto,
159						       __wsum sum)
160{
161	return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
162}
163
164/*
165 * this routine is used for miscellaneous IP-like checksums, mainly
166 * in icmp.c
167 */
168
169static __inline__ __sum16 ip_compute_csum(const void *buff, int len)
170{
171    return csum_fold (csum_partial(buff, len, 0));
172}
173
174#define _HAVE_ARCH_IPV6_CSUM
175static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
176					  const struct in6_addr *daddr,
177					  __u32 len, unsigned short proto,
178					  __wsum sum)
179{
180	unsigned int __dummy;
181	__asm__("l32i	%1, %2, 0\n\t"
182		"add	%0, %0, %1\n\t"
183		"bgeu	%0, %1, 1f\n\t"
184		"addi	%0, %0, 1\n\t"
185		"1:\t"
186		"l32i	%1, %2, 4\n\t"
187		"add	%0, %0, %1\n\t"
188		"bgeu	%0, %1, 1f\n\t"
189		"addi	%0, %0, 1\n\t"
190		"1:\t"
191		"l32i	%1, %2, 8\n\t"
192		"add	%0, %0, %1\n\t"
193		"bgeu	%0, %1, 1f\n\t"
194		"addi	%0, %0, 1\n\t"
195		"1:\t"
196		"l32i	%1, %2, 12\n\t"
197		"add	%0, %0, %1\n\t"
198		"bgeu	%0, %1, 1f\n\t"
199		"addi	%0, %0, 1\n\t"
200		"1:\t"
201		"l32i	%1, %3, 0\n\t"
202		"add	%0, %0, %1\n\t"
203		"bgeu	%0, %1, 1f\n\t"
204		"addi	%0, %0, 1\n\t"
205		"1:\t"
206		"l32i	%1, %3, 4\n\t"
207		"add	%0, %0, %1\n\t"
208		"bgeu	%0, %1, 1f\n\t"
209		"addi	%0, %0, 1\n\t"
210		"1:\t"
211		"l32i	%1, %3, 8\n\t"
212		"add	%0, %0, %1\n\t"
213		"bgeu	%0, %1, 1f\n\t"
214		"addi	%0, %0, 1\n\t"
215		"1:\t"
216		"l32i	%1, %3, 12\n\t"
217		"add	%0, %0, %1\n\t"
218		"bgeu	%0, %1, 1f\n\t"
219		"addi	%0, %0, 1\n\t"
220		"1:\t"
221		"add	%0, %0, %4\n\t"
222		"bgeu	%0, %4, 1f\n\t"
223		"addi	%0, %0, 1\n\t"
224		"1:\t"
225		"add	%0, %0, %5\n\t"
226		"bgeu	%0, %5, 1f\n\t"
227		"addi	%0, %0, 1\n\t"
228		"1:\t"
229		: "=r" (sum), "=&r" (__dummy)
230		: "r" (saddr), "r" (daddr),
231		  "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
232		: "memory");
233
234	return csum_fold(sum);
235}
236
237/*
238 *	Copy and checksum to user
239 */
240#define HAVE_CSUM_COPY_USER
241static __inline__ __wsum csum_and_copy_to_user(const void *src, void __user *dst,
242				    int len, __wsum sum, int *err_ptr)
243{
244	if (access_ok(VERIFY_WRITE, dst, len))
245		return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
246
247	if (len)
248		*err_ptr = -EFAULT;
249
250	return (__force __wsum)-1; /* invalid checksum */
251}
252#endif