aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/lib/checksum_32.S
blob: 0a57fe6d49ccf43a07224c4f7da1f597e36cc10c (plain)
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
/*
 * This file contains assembly-language implementations
 * of IP-style 1's complement checksum routines.
 *	
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  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.
 *
 * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au).
 */

#include <linux/sys.h>
#include <asm/processor.h>
#include <asm/cache.h>
#include <asm/errno.h>
#include <asm/ppc_asm.h>

	.text

/*
 * computes the checksum of a memory block at buff, length len,
 * and adds in "sum" (32-bit)
 *
 * __csum_partial(buff, len, sum)
 */
_GLOBAL(__csum_partial)
	subi	r3,r3,4
	srawi.	r6,r4,2		/* Divide len by 4 and also clear carry */
	beq	3f		/* if we're doing < 4 bytes */
	andi.	r0,r3,2		/* Align buffer to longword boundary */
	beq+	1f
	lhz	r0,4(r3)	/* do 2 bytes to get aligned */
	subi	r4,r4,2
	addi	r3,r3,2
	srwi.	r6,r4,2		/* # words to do */
	adde	r5,r5,r0
	beq	3f
1:	andi.	r6,r6,3		/* Prepare to handle words 4 by 4 */
	beq	21f
	mtctr	r6
2:	lwzu	r0,4(r3)
	adde	r5,r5,r0
	bdnz	2b
21:	srwi.	r6,r4,4		/* # blocks of 4 words to do */
	beq	3f
	mtctr	r6
22:	lwz	r0,4(r3)
	lwz	r6,8(r3)
	lwz	r7,12(r3)
	lwzu	r8,16(r3)
	adde	r5,r5,r0
	adde	r5,r5,r6
	adde	r5,r5,r7
	adde	r5,r5,r8
	bdnz	22b
3:	andi.	r0,r4,2
	beq+	4f
	lhz	r0,4(r3)
	addi	r3,r3,2
	adde	r5,r5,r0
4:	andi.	r0,r4,1
	beq+	5f
	lbz	r0,4(r3)
	slwi	r0,r0,8		/* Upper byte of word */
	adde	r5,r5,r0
5:	addze	r3,r5		/* add in final carry */
	blr

/*
 * Computes the checksum of a memory block at src, length len,
 * and adds in "sum" (32-bit), while copying the block to dst.
 * If an access exception occurs on src or dst, it stores -EFAULT
 * to *src_err or *dst_err respectively, and (for an error on
 * src) zeroes the rest of dst.
 *
 * csum_partial_copy_generic(src, dst, len, sum, src_err, dst_err)
 */
#define CSUM_COPY_16_BYTES_WITHEX(n)	\
8 ## n ## 0:			\
	lwz	r7,4(r4);	\
8 ## n ## 1:			\
	lwz	r8,8(r4);	\
8 ## n ## 2:			\
	lwz	r9,12(r4);	\
8 ## n ## 3:			\
	lwzu	r10,16(r4);	\
8 ## n ## 4:			\
	stw	r7,4(r6);	\
	adde	r12,r12,r7;	\
8 ## n ## 5:			\
	stw	r8,8(r6);	\
	adde	r12,r12,r8;	\
8 ## n ## 6:			\
	stw	r9,12(r6);	\
	adde	r12,r12,r9;	\
8 ## n ## 7:			\
	stwu	r10,16(r6);	\
	adde	r12,r12,r10

#define CSUM_COPY_16_BYTES_EXCODE(n)		\
.section __ex_table,"a";		\
	.align	2;			\
	.long	8 ## n ## 0b,src_error;	\
	.long	8 ## n ## 1b,src_error;	\
	.long	8 ## n ## 2b,src_error;	\
	.long	8 ## n ## 3b,src_error;	\
	.long	8 ## n ## 4b,dst_error;	\
	.long	8 ## n ## 5b,dst_error;	\
	.long	8 ## n ## 6b,dst_error;	\
	.long	8 ## n ## 7b,dst_error;	\
	.text

	.text
	.stabs	"arch/powerpc/lib/",N_SO,0,0,0f
	.stabs	"checksum_32.S",N_SO,0,0,0f
0:

CACHELINE_BYTES = L1_CACHE_BYTES
LG_CACHELINE_BYTES = L1_CACHE_SHIFT
CACHELINE_MASK = (L1_CACHE_BYTES-1)

_GLOBAL(csum_partial_copy_generic)
	stwu	r1,-16(r1)
	stw	r7,12(r1)
	stw	r8,8(r1)

	rlwinm	r0,r4,3,0x8
	rlwnm	r6,r6,r0,0,31	/* odd destination address: rotate one byte */
	cmplwi	cr7,r0,0	/* is destination address even ? */
	addic	r12,r6,0
	addi	r6,r4,-4
	neg	r0,r4
	addi	r4,r3,-4
	andi.	r0,r0,CACHELINE_MASK	/* # bytes to start of cache line */
	beq	58f

	cmplw	0,r5,r0			/* is this more than total to do? */
	blt	63f			/* if not much to do */
	andi.	r8,r0,3			/* get it word-aligned first */
	mtctr	r8
	beq+	61f
	li	r3,0
70:	lbz	r9,4(r4)		/* do some bytes */
	addi	r4,r4,1
	slwi	r3,r3,8
	rlwimi	r3,r9,0,24,31
71:	stb	r9,4(r6)
	addi	r6,r6,1
	bdnz	70b
	adde	r12,r12,r3
61:	subf	r5,r0,r5
	srwi.	r0,r0,2
	mtctr	r0
	beq	58f
72:	lwzu	r9,4(r4)		/* do some words */
	adde	r12,r12,r9
73:	stwu	r9,4(r6)
	bdnz	72b

58:	srwi.	r0,r5,LG_CACHELINE_BYTES /* # complete cachelines */
	clrlwi	r5,r5,32-LG_CACHELINE_BYTES
	li	r11,4
	beq	63f

	/* Here we decide how far ahead to prefetch the source */
	li	r3,4
	cmpwi	r0,1
	li	r7,0
	ble	114f
	li	r7,1
#if MAX_COPY_PREFETCH > 1
	/* Heuristically, for large transfers we prefetch
	   MAX_COPY_PREFETCH cachelines ahead.  For small transfers
	   we prefetch 1 cacheline ahead. */
	cmpwi	r0,MAX_COPY_PREFETCH
	ble	112f
	li	r7,MAX_COPY_PREFETCH
112:	mtctr	r7
111:	dcbt	r3,r4
	addi	r3,r3,CACHELINE_BYTES
	bdnz	111b
#else
	dcbt	r3,r4
	addi	r3,r3,CACHELINE_BYTES
#endif /* MAX_COPY_PREFETCH > 1 */

114:	subf	r8,r7,r0
	mr	r0,r7
	mtctr	r8

53:	dcbt	r3,r4
54:	dcbz	r11,r6
/* the main body of the cacheline loop */
	CSUM_COPY_16_BYTES_WITHEX(0)
#if L1_CACHE_BYTES >= 32
	CSUM_COPY_16_BYTES_WITHEX(1)
#if L1_CACHE_BYTES >= 64
	CSUM_COPY_16_BYTES_WITHEX(2)
	CSUM_COPY_16_BYTES_WITHEX(3)
#if L1_CACHE_BYTES >= 128
	CSUM_COPY_16_BYTES_WITHEX(4)
	CSUM_COPY_16_BYTES_WITHEX(5)
	CSUM_COPY_16_BYTES_WITHEX(6)
	CSUM_COPY_16_BYTES_WITHEX(7)
#endif
#endif
#endif
	bdnz	53b
	cmpwi	r0,0
	li	r3,4
	li	r7,0
	bne	114b

63:	srwi.	r0,r5,2
	mtctr	r0
	beq	64f
30:	lwzu	r0,4(r4)
	adde	r12,r12,r0
31:	stwu	r0,4(r6)
	bdnz	30b

64:	andi.	r0,r5,2
	beq+	65f
40:	lhz	r0,4(r4)
	addi	r4,r4,2
41:	sth	r0,4(r6)
	adde	r12,r12,r0
	addi	r6,r6,2
65:	andi.	r0,r5,1
	beq+	66f
50:	lbz	r0,4(r4)
51:	stb	r0,4(r6)
	slwi	r0,r0,8
	adde	r12,r12,r0
66:	addze	r3,r12
	addi	r1,r1,16
	beqlr+	cr7
	rlwinm	r3,r3,8,0,31	/* odd destination address: rotate one byte */
	blr

/* read fault */
src_error:
	lwz	r7,12(r1)
	addi	r1,r1,16
	cmpwi	cr0,r7,0
	beqlr
	li	r0,-EFAULT
	stw	r0,0(r7)
	blr
/* write fault */
dst_error:
	lwz	r8,8(r1)
	addi	r1,r1,16
	cmpwi	cr0,r8,0
	beqlr
	li	r0,-EFAULT
	stw	r0,0(r8)
	blr

	.section __ex_table,"a"
	.align	2
	.long	70b,src_error
	.long	71b,dst_error
	.long	72b,src_error
	.long	73b,dst_error
	.long	54b,dst_error
	.text

/*
 * this stuff handles faults in the cacheline loop and branches to either
 * src_error (if in read part) or dst_error (if in write part)
 */
	CSUM_COPY_16_BYTES_EXCODE(0)
#if L1_CACHE_BYTES >= 32
	CSUM_COPY_16_BYTES_EXCODE(1)
#if L1_CACHE_BYTES >= 64
	CSUM_COPY_16_BYTES_EXCODE(2)
	CSUM_COPY_16_BYTES_EXCODE(3)
#if L1_CACHE_BYTES >= 128
	CSUM_COPY_16_BYTES_EXCODE(4)
	CSUM_COPY_16_BYTES_EXCODE(5)
	CSUM_COPY_16_BYTES_EXCODE(6)
	CSUM_COPY_16_BYTES_EXCODE(7)
#endif
#endif
#endif

	.section __ex_table,"a"
	.align	2
	.long	30b,src_error
	.long	31b,dst_error
	.long	40b,src_error
	.long	41b,dst_error
	.long	50b,src_error
	.long	51b,dst_error