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
|
/*
* arch/s390/lib/uaccess.S
* __copy_{from|to}_user functions.
*
* s390
* Copyright (C) 2000,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Authors(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* These functions have standard call interface
*/
#include <linux/errno.h>
#include <asm/lowcore.h>
#include <asm/asm-offsets.h>
.text
.align 4
.globl __copy_from_user_asm
# %r2 = to, %r3 = n, %r4 = from
__copy_from_user_asm:
slr %r0,%r0
0: mvcp 0(%r3,%r2),0(%r4),%r0
jnz 1f
slr %r2,%r2
br %r14
1: la %r2,256(%r2)
la %r4,256(%r4)
ahi %r3,-256
2: mvcp 0(%r3,%r2),0(%r4),%r0
jnz 1b
3: slr %r2,%r2
br %r14
4: lhi %r0,-4096
lr %r5,%r4
slr %r5,%r0
nr %r5,%r0 # %r5 = (%r4 + 4096) & -4096
slr %r5,%r4 # %r5 = #bytes to next user page boundary
clr %r3,%r5 # copy crosses next page boundary ?
jnh 6f # no, the current page faulted
# move with the reduced length which is < 256
5: mvcp 0(%r5,%r2),0(%r4),%r0
slr %r3,%r5
6: lr %r2,%r3
br %r14
.section __ex_table,"a"
.long 0b,4b
.long 2b,4b
.long 5b,6b
.previous
.align 4
.text
.globl __copy_to_user_asm
# %r2 = from, %r3 = n, %r4 = to
__copy_to_user_asm:
slr %r0,%r0
0: mvcs 0(%r3,%r4),0(%r2),%r0
jnz 1f
slr %r2,%r2
br %r14
1: la %r2,256(%r2)
la %r4,256(%r4)
ahi %r3,-256
2: mvcs 0(%r3,%r4),0(%r2),%r0
jnz 1b
3: slr %r2,%r2
br %r14
4: lhi %r0,-4096
lr %r5,%r4
slr %r5,%r0
nr %r5,%r0 # %r5 = (%r4 + 4096) & -4096
slr %r5,%r4 # %r5 = #bytes to next user page boundary
clr %r3,%r5 # copy crosses next page boundary ?
jnh 6f # no, the current page faulted
# move with the reduced length which is < 256
5: mvcs 0(%r5,%r4),0(%r2),%r0
slr %r3,%r5
6: lr %r2,%r3
br %r14
.section __ex_table,"a"
.long 0b,4b
.long 2b,4b
.long 5b,6b
.previous
.align 4
.text
.globl __copy_in_user_asm
# %r2 = from, %r3 = n, %r4 = to
__copy_in_user_asm:
sacf 256
bras 1,1f
mvc 0(1,%r4),0(%r2)
0: mvc 0(256,%r4),0(%r2)
la %r2,256(%r2)
la %r4,256(%r4)
1: ahi %r3,-256
jnm 0b
2: ex %r3,0(%r1)
sacf 0
slr %r2,%r2
br 14
3: mvc 0(1,%r4),0(%r2)
la %r2,1(%r2)
la %r4,1(%r4)
ahi %r3,-1
jnm 3b
4: lr %r2,%r3
sacf 0
br %r14
.section __ex_table,"a"
.long 0b,3b
.long 2b,3b
.long 3b,4b
.previous
.align 4
.text
.globl __clear_user_asm
# %r2 = to, %r3 = n
__clear_user_asm:
bras %r5,0f
.long empty_zero_page
0: l %r5,0(%r5)
slr %r0,%r0
1: mvcs 0(%r3,%r2),0(%r5),%r0
jnz 2f
slr %r2,%r2
br %r14
2: la %r2,256(%r2)
ahi %r3,-256
3: mvcs 0(%r3,%r2),0(%r5),%r0
jnz 2b
4: slr %r2,%r2
br %r14
5: lhi %r0,-4096
lr %r4,%r2
slr %r4,%r0
nr %r4,%r0 # %r4 = (%r2 + 4096) & -4096
slr %r4,%r2 # %r4 = #bytes to next user page boundary
clr %r3,%r4 # clear crosses next page boundary ?
jnh 7f # no, the current page faulted
# clear with the reduced length which is < 256
6: mvcs 0(%r4,%r2),0(%r5),%r0
slr %r3,%r4
7: lr %r2,%r3
br %r14
.section __ex_table,"a"
.long 1b,5b
.long 3b,5b
.long 6b,7b
.previous
.align 4
.text
.globl __strncpy_from_user_asm
# %r2 = count, %r3 = dst, %r4 = src
__strncpy_from_user_asm:
lhi %r0,0
lr %r1,%r4
la %r4,0(%r4) # clear high order bit from %r4
la %r2,0(%r2,%r4) # %r2 points to first byte after string
sacf 256
0: srst %r2,%r1
jo 0b
sacf 0
lr %r1,%r2
jh 1f # \0 found in string ?
ahi %r1,1 # include \0 in copy
1: slr %r1,%r4 # %r1 = copy length (without \0)
slr %r2,%r4 # %r2 = return length (including \0)
2: mvcp 0(%r1,%r3),0(%r4),%r0
jnz 3f
br %r14
3: la %r3,256(%r3)
la %r4,256(%r4)
ahi %r1,-256
mvcp 0(%r1,%r3),0(%r4),%r0
jnz 3b
br %r14
4: sacf 0
lhi %r2,-EFAULT
br %r14
.section __ex_table,"a"
.long 0b,4b
.previous
.align 4
.text
.globl __strnlen_user_asm
# %r2 = count, %r3 = src
__strnlen_user_asm:
lhi %r0,0
lr %r1,%r3
la %r3,0(%r3) # clear high order bit from %r4
la %r2,0(%r2,%r3) # %r2 points to first byte after string
sacf 256
0: srst %r2,%r1
jo 0b
sacf 0
ahi %r2,1 # strnlen_user result includes the \0
# or return count+1 if \0 not found
slr %r2,%r3
br %r14
2: sacf 0
slr %r2,%r2 # return 0 on exception
br %r14
.section __ex_table,"a"
.long 0b,2b
.previous
|
