aboutsummaryrefslogtreecommitdiffstats
path: root/arch/m68k/lib/checksum.c
blob: cb13c6e3ccaeb6449dd2d99898f9e1ee53eb50d5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		IP/TCP/UDP checksumming routines
 *
 * Authors:	Jorge Cwik, <jorge@laser.satlink.net>
 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 *		Tom May, <ftom@netcom.com>
 *		Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de>
 *		Lots of code moved from tcp.c and ip.c; see those files
 *		for more names.
 *
 * 03/02/96	Jes Sorensen, Andreas Schwab, Roman Hodek:
 *		Fixed some nasty bugs, causing some horrible crashes.
 *		A: At some points, the sum (%0) was used as
 *		length-counter instead of the length counter
 *		(%1). Thanks to Roman Hodek for pointing this out.
 *		B: GCC seems to mess up if one uses too many
 *		data-registers to hold input values and one tries to
 *		specify d0 and d1 as scratch registers. Letting gcc
 *		choose these registers itself solves the problem.
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * 1998/8/31	Andreas Schwab:
 *		Zero out rest of buffer on exception in
 *		csum_partial_copy_from_user.
 */

#include <linux/module.h>
#include <net/checksum.h>

/*
 * computes a partial checksum, e.g. for TCP/UDP fragments
 */

unsigned int
csum_partial (const unsigned char *buff, int len, unsigned int sum)
{
	unsigned long tmp1, tmp2;
	  /*
	   * Experiments with ethernet and slip connections show that buff
	   * is aligned on either a 2-byte or 4-byte boundary.
	   */
	__asm__("movel %2,%3\n\t"
		"btst #1,%3\n\t"	/* Check alignment */
		"jeq 2f\n\t"
		"subql #2,%1\n\t"	/* buff%4==2: treat first word */
		"jgt 1f\n\t"
		"addql #2,%1\n\t"	/* len was == 2, treat only rest */
		"jra 4f\n"
	     "1:\t"
		"addw %2@+,%0\n\t"	/* add first word to sum */
		"clrl %3\n\t"
		"addxl %3,%0\n"		/* add X bit */
	     "2:\t"
		/* unrolled loop for the main part: do 8 longs at once */
		"movel %1,%3\n\t"	/* save len in tmp1 */
		"lsrl #5,%1\n\t"	/* len/32 */
		"jeq 2f\n\t"		/* not enough... */
		"subql #1,%1\n"
	     "1:\t"
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"dbra %1,1b\n\t"
		"clrl %4\n\t"
		"addxl %4,%0\n\t"	/* add X bit */
		"clrw %1\n\t"
		"subql #1,%1\n\t"
		"jcc 1b\n"
	     "2:\t"
		"movel %3,%1\n\t"	/* restore len from tmp1 */
		"andw #0x1c,%3\n\t"	/* number of rest longs */
		"jeq 4f\n\t"
		"lsrw #2,%3\n\t"
		"subqw #1,%3\n"
	     "3:\t"
		/* loop for rest longs */
		"movel %2@+,%4\n\t"
		"addxl %4,%0\n\t"
		"dbra %3,3b\n\t"
		"clrl %4\n\t"
		"addxl %4,%0\n"		/* add X bit */
	     "4:\t"
		/* now check for rest bytes that do not fit into longs */
		"andw #3,%1\n\t"
		"jeq 7f\n\t"
		"clrl %4\n\t"		/* clear tmp2 for rest bytes */
		"subqw #2,%1\n\t"
		"jlt 5f\n\t"
		"movew %2@+,%4\n\t"	/* have rest >= 2: get word */
		"swap %4\n\t"		/* into bits 16..31 */
		"tstw %1\n\t"		/* another byte? */
		"jeq 6f\n"
	     "5:\t"
		"moveb %2@,%4\n\t"	/* have odd rest: get byte */
		"lslw #8,%4\n\t"	/* into bits 8..15; 16..31 untouched */
	     "6:\t"
		"addl %4,%0\n\t"	/* now add rest long to sum */
		"clrl %4\n\t"
		"addxl %4,%0\n"		/* add X bit */
	     "7:\t"
		: "=d" (sum), "=d" (len), "=a" (buff),
		  "=&d" (tmp1), "=&d" (tmp2)
		: "0" (sum), "1" (len), "2" (buff)
	    );
	return(sum);
}

EXPORT_SYMBOL(csum_partial);


/*
 * copy from user space while checksumming, with exception handling.
 */

unsigned int
csum_partial_copy_from_user(const unsigned char __user *src, unsigned char *dst,
			    int len, int sum, int *csum_err)
{
	/*
	 * GCC doesn't like more than 10 operands for the asm
	 * statements so we have to use tmp2 for the error
	 * code.
	 */
	unsigned long tmp1, tmp2;

	__asm__("movel %2,%4\n\t"
		"btst #1,%4\n\t"	/* Check alignment */
		"jeq 2f\n\t"
		"subql #2,%1\n\t"	/* buff%4==2: treat first word */
		"jgt 1f\n\t"
		"addql #2,%1\n\t"	/* len was == 2, treat only rest */
		"jra 4f\n"
	     "1:\n"
	     "10:\t"
		"movesw %2@+,%4\n\t"	/* add first word to sum */
		"addw %4,%0\n\t"
		"movew %4,%3@+\n\t"
		"clrl %4\n\t"
		"addxl %4,%0\n"		/* add X bit */
	     "2:\t"
		/* unrolled loop for the main part: do 8 longs at once */
		"movel %1,%4\n\t"	/* save len in tmp1 */
		"lsrl #5,%1\n\t"	/* len/32 */
		"jeq 2f\n\t"		/* not enough... */
		"subql #1,%1\n"
	     "1:\n"
	     "11:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
	     "12:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
	     "13:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
	     "14:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
	     "15:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
	     "16:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
	     "17:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
	     "18:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"dbra %1,1b\n\t"
		"clrl %5\n\t"
		"addxl %5,%0\n\t"	/* add X bit */
		"clrw %1\n\t"
		"subql #1,%1\n\t"
		"jcc 1b\n"
	     "2:\t"
		"movel %4,%1\n\t"	/* restore len from tmp1 */
		"andw #0x1c,%4\n\t"	/* number of rest longs */
		"jeq 4f\n\t"
		"lsrw #2,%4\n\t"
		"subqw #1,%4\n"
	     "3:\n"
		/* loop for rest longs */
	     "19:\t"
		"movesl %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"dbra %4,3b\n\t"
		"clrl %5\n\t"
		"addxl %5,%0\n"		/* add X bit */
	     "4:\t"
		/* now check for rest bytes that do not fit into longs */
		"andw #3,%1\n\t"
		"jeq 7f\n\t"
		"clrl %5\n\t"		/* clear tmp2 for rest bytes */
		"subqw #2,%1\n\t"
		"jlt 5f\n\t"
	     "20:\t"
		"movesw %2@+,%5\n\t"	/* have rest >= 2: get word */
		"movew %5,%3@+\n\t"
		"swap %5\n\t"		/* into bits 16..31 */
		"tstw %1\n\t"		/* another byte? */
		"jeq 6f\n"
	     "5:\n"
	     "21:\t"
		"movesb %2@,%5\n\t"	/* have odd rest: get byte */
		"moveb %5,%3@+\n\t"
		"lslw #8,%5\n\t"	/* into bits 8..15; 16..31 untouched */
	     "6:\t"
		"addl %5,%0\n\t"	/* now add rest long to sum */
		"clrl %5\n\t"
		"addxl %5,%0\n\t"	/* add X bit */
	     "7:\t"
		"clrl %5\n"		/* no error - clear return value */
	     "8:\n"
		".section .fixup,\"ax\"\n"
		".even\n"
		/* If any exception occurs zero out the rest.
		   Similarities with the code above are intentional :-) */
	     "90:\t"
		"clrw %3@+\n\t"
		"movel %1,%4\n\t"
		"lsrl #5,%1\n\t"
		"jeq 1f\n\t"
		"subql #1,%1\n"
	     "91:\t"
		"clrl %3@+\n"
	     "92:\t"
		"clrl %3@+\n"
	     "93:\t"
		"clrl %3@+\n"
	     "94:\t"
		"clrl %3@+\n"
	     "95:\t"
		"clrl %3@+\n"
	     "96:\t"
		"clrl %3@+\n"
	     "97:\t"
		"clrl %3@+\n"
	     "98:\t"
		"clrl %3@+\n\t"
		"dbra %1,91b\n\t"
		"clrw %1\n\t"
		"subql #1,%1\n\t"
		"jcc 91b\n"
	     "1:\t"
		"movel %4,%1\n\t"
		"andw #0x1c,%4\n\t"
		"jeq 1f\n\t"
		"lsrw #2,%4\n\t"
		"subqw #1,%4\n"
	     "99:\t"
		"clrl %3@+\n\t"
		"dbra %4,99b\n\t"
	     "1:\t"
		"andw #3,%1\n\t"
		"jeq 9f\n"
	     "100:\t"
		"clrw %3@+\n\t"
		"tstw %1\n\t"
		"jeq 9f\n"
	     "101:\t"
		"clrb %3@+\n"
	     "9:\t"
#define STR(X) STR1(X)
#define STR1(X) #X
		"moveq #-" STR(EFAULT) ",%5\n\t"
		"jra 8b\n"
		".previous\n"
		".section __ex_table,\"a\"\n"
		".long 10b,90b\n"
		".long 11b,91b\n"
		".long 12b,92b\n"
		".long 13b,93b\n"
		".long 14b,94b\n"
		".long 15b,95b\n"
		".long 16b,96b\n"
		".long 17b,97b\n"
		".long 18b,98b\n"
		".long 19b,99b\n"
		".long 20b,100b\n"
		".long 21b,101b\n"
		".previous"
		: "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
		  "=&d" (tmp1), "=d" (tmp2)
		: "0" (sum), "1" (len), "2" (src), "3" (dst)
	    );

	*csum_err = tmp2;

	return(sum);
}

/*
 * copy from kernel space while checksumming, otherwise like csum_partial
 */

unsigned int
csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, int len, int sum)
{
	unsigned long tmp1, tmp2;
	__asm__("movel %2,%4\n\t"
		"btst #1,%4\n\t"	/* Check alignment */
		"jeq 2f\n\t"
		"subql #2,%1\n\t"	/* buff%4==2: treat first word */
		"jgt 1f\n\t"
		"addql #2,%1\n\t"	/* len was == 2, treat only rest */
		"jra 4f\n"
	     "1:\t"
		"movew %2@+,%4\n\t"	/* add first word to sum */
		"addw %4,%0\n\t"
		"movew %4,%3@+\n\t"
		"clrl %4\n\t"
		"addxl %4,%0\n"		/* add X bit */
	     "2:\t"
		/* unrolled loop for the main part: do 8 longs at once */
		"movel %1,%4\n\t"	/* save len in tmp1 */
		"lsrl #5,%1\n\t"	/* len/32 */
		"jeq 2f\n\t"		/* not enough... */
		"subql #1,%1\n"
	     "1:\t"
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"dbra %1,1b\n\t"
		"clrl %5\n\t"
		"addxl %5,%0\n\t"	/* add X bit */
		"clrw %1\n\t"
		"subql #1,%1\n\t"
		"jcc 1b\n"
	     "2:\t"
		"movel %4,%1\n\t"	/* restore len from tmp1 */
		"andw #0x1c,%4\n\t"	/* number of rest longs */
		"jeq 4f\n\t"
		"lsrw #2,%4\n\t"
		"subqw #1,%4\n"
	     "3:\t"
		/* loop for rest longs */
		"movel %2@+,%5\n\t"
		"addxl %5,%0\n\t"
		"movel %5,%3@+\n\t"
		"dbra %4,3b\n\t"
		"clrl %5\n\t"
		"addxl %5,%0\n"		/* add X bit */
	     "4:\t"
		/* now check for rest bytes that do not fit into longs */
		"andw #3,%1\n\t"
		"jeq 7f\n\t"
		"clrl %5\n\t"		/* clear tmp2 for rest bytes */
		"subqw #2,%1\n\t"
		"jlt 5f\n\t"
		"movew %2@+,%5\n\t"	/* have rest >= 2: get word */
		"movew %5,%3@+\n\t"
		"swap %5\n\t"		/* into bits 16..31 */
		"tstw %1\n\t"		/* another byte? */
		"jeq 6f\n"
	     "5:\t"
		"moveb %2@,%5\n\t"	/* have odd rest: get byte */
		"moveb %5,%3@+\n\t"
		"lslw #8,%5\n"		/* into bits 8..15; 16..31 untouched */
	     "6:\t"
		"addl %5,%0\n\t"	/* now add rest long to sum */
		"clrl %5\n\t"
		"addxl %5,%0\n"		/* add X bit */
	     "7:\t"
		: "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
		  "=&d" (tmp1), "=&d" (tmp2)
		: "0" (sum), "1" (len), "2" (src), "3" (dst)
	    );
    return(sum);
}