string_64.S
3.42 KB
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
/*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2012
*
* Author: Anton Blanchard <anton@au.ibm.com>
*/
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
.section ".toc","aw"
PPC64_CACHES:
.tc ppc64_caches[TC],ppc64_caches
.section ".text"
/**
* __clear_user: - Zero a block of memory in user space, with less checking.
* @to: Destination address, in user space.
* @n: Number of bytes to zero.
*
* Zero a block of memory in user space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be cleared.
* On success, this will be zero.
*/
.macro err1
100:
.section __ex_table,"a"
.align 3
.llong 100b,.Ldo_err1
.previous
.endm
.macro err2
200:
.section __ex_table,"a"
.align 3
.llong 200b,.Ldo_err2
.previous
.endm
.macro err3
300:
.section __ex_table,"a"
.align 3
.llong 300b,.Ldo_err3
.previous
.endm
.Ldo_err1:
mr r3,r8
.Ldo_err2:
mtctr r4
1:
err3; stb r0,0(r3)
addi r3,r3,1
addi r4,r4,-1
bdnz 1b
.Ldo_err3:
mr r3,r4
blr
_GLOBAL_TOC(__clear_user)
cmpdi r4,32
neg r6,r3
li r0,0
blt .Lshort_clear
mr r8,r3
mtocrf 0x01,r6
clrldi r6,r6,(64-3)
/* Get the destination 8 byte aligned */
bf cr7*4+3,1f
err1; stb r0,0(r3)
addi r3,r3,1
1: bf cr7*4+2,2f
err1; sth r0,0(r3)
addi r3,r3,2
2: bf cr7*4+1,3f
err1; stw r0,0(r3)
addi r3,r3,4
3: sub r4,r4,r6
cmpdi r4,32
cmpdi cr1,r4,512
blt .Lshort_clear
bgt cr1,.Llong_clear
.Lmedium_clear:
srdi r6,r4,5
mtctr r6
/* Do 32 byte chunks */
4:
err2; std r0,0(r3)
err2; std r0,8(r3)
err2; std r0,16(r3)
err2; std r0,24(r3)
addi r3,r3,32
addi r4,r4,-32
bdnz 4b
.Lshort_clear:
/* up to 31 bytes to go */
cmpdi r4,16
blt 6f
err2; std r0,0(r3)
err2; std r0,8(r3)
addi r3,r3,16
addi r4,r4,-16
/* Up to 15 bytes to go */
6: mr r8,r3
clrldi r4,r4,(64-4)
mtocrf 0x01,r4
bf cr7*4+0,7f
err1; std r0,0(r3)
addi r3,r3,8
7: bf cr7*4+1,8f
err1; stw r0,0(r3)
addi r3,r3,4
8: bf cr7*4+2,9f
err1; sth r0,0(r3)
addi r3,r3,2
9: bf cr7*4+3,10f
err1; stb r0,0(r3)
10: li r3,0
blr
.Llong_clear:
ld r5,PPC64_CACHES@toc(r2)
bf cr7*4+0,11f
err2; std r0,0(r3)
addi r3,r3,8
addi r4,r4,-8
/* Destination is 16 byte aligned, need to get it cacheline aligned */
11: lwz r7,DCACHEL1LOGLINESIZE(r5)
lwz r9,DCACHEL1LINESIZE(r5)
/*
* With worst case alignment the long clear loop takes a minimum
* of 1 byte less than 2 cachelines.
*/
sldi r10,r9,2
cmpd r4,r10
blt .Lmedium_clear
neg r6,r3
addi r10,r9,-1
and. r5,r6,r10
beq 13f
srdi r6,r5,4
mtctr r6
mr r8,r3
12:
err1; std r0,0(r3)
err1; std r0,8(r3)
addi r3,r3,16
bdnz 12b
sub r4,r4,r5
13: srd r6,r4,r7
mtctr r6
mr r8,r3
14:
err1; dcbz r0,r3
add r3,r3,r9
bdnz 14b
and r4,r4,r10
cmpdi r4,32
blt .Lshort_clear
b .Lmedium_clear