aboutsummaryrefslogtreecommitdiffstats
path: root/arch/s390/lib/uaccess64.S
blob: 19b41a33c230cb02e1d5f527cb3c43bb12de0e31 (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
/*
 *  arch/s390x/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:
	slgr	%r0,%r0
0:	mvcp	0(%r3,%r2),0(%r4),%r0
	jnz	1f
	slgr	%r2,%r2
	br	%r14
1:	la	%r2,256(%r2)
	la	%r4,256(%r4)
	aghi	%r3,-256
2:	mvcp	0(%r3,%r2),0(%r4),%r0
	jnz	1b
3:	slgr	%r2,%r2
	br	%r14
4:	lghi	%r0,-4096
	lgr	%r5,%r4
	slgr	%r5,%r0
	ngr	%r5,%r0		# %r5 = (%r4 + 4096) & -4096
	slgr	%r5,%r4		# %r5 = #bytes to next user page boundary
	clgr	%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
	slgr	%r3,%r5
6:	lgr	%r2,%r3
	br	%r14
        .section __ex_table,"a"
	.quad	0b,4b
	.quad	2b,4b
	.quad	5b,6b
        .previous

        .align 4
        .text
        .globl __copy_to_user_asm
	# %r2 = from, %r3 = n, %r4 = to
__copy_to_user_asm:
	slgr	%r0,%r0
0:	mvcs	0(%r3,%r4),0(%r2),%r0
	jnz	1f
	slgr	%r2,%r2
	br	%r14
1:	la	%r2,256(%r2)
	la	%r4,256(%r4)
	aghi	%r3,-256
2:	mvcs	0(%r3,%r4),0(%r2),%r0
	jnz	1b
3:	slgr	%r2,%r2
	br	%r14
4:	lghi	%r0,-4096
	lgr	%r5,%r4
	slgr	%r5,%r0
	ngr	%r5,%r0		# %r5 = (%r4 + 4096) & -4096
	slgr	%r5,%r4		# %r5 = #bytes to next user page boundary
	clgr	%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
	slgr	%r3,%r5
6:	lgr	%r2,%r3
	br	%r14
        .section __ex_table,"a"
	.quad	0b,4b
	.quad	2b,4b
	.quad	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:	aghi	%r3,-256
	jnm	0b
2:	ex	%r3,0(%r1)
	sacf	0
	slgr	%r2,%r2
	br	14
3:	mvc	0(1,%r4),0(%r2)
	la	%r2,1(%r2)
	la	%r4,1(%r4)
	aghi	%r3,-1
	jnm	3b
4:	lgr	%r2,%r3
	sacf	0
	br	%r14
        .section __ex_table,"a"
	.quad	0b,3b
	.quad	2b,3b
	.quad	3b,4b
        .previous

        .align 4
        .text
        .globl __clear_user_asm
	# %r2 = to, %r3 = n
__clear_user_asm:
	slgr	%r0,%r0
	larl	%r5,empty_zero_page
1:	mvcs	0(%r3,%r2),0(%r5),%r0
	jnz	2f
	slgr	%r2,%r2
	br	%r14
2:	la	%r2,256(%r2)
	aghi	%r3,-256
3:	mvcs	0(%r3,%r2),0(%r5),%r0
	jnz	2b
4:	slgr	%r2,%r2
	br	%r14
5:	lghi	%r0,-4096
	lgr	%r4,%r2
	slgr	%r4,%r0
	ngr	%r4,%r0		# %r4 = (%r2 + 4096) & -4096
	slgr	%r4,%r2		# %r4 = #bytes to next user page boundary
	clgr	%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
	slgr	%r3,%r4
7:	lgr	%r2,%r3
	br	%r14
        .section __ex_table,"a"
	.quad	1b,5b
	.quad	3b,5b
	.quad	6b,7b
        .previous

        .align 4
        .text
        .globl __strncpy_from_user_asm
	# %r2 = count, %r3 = dst, %r4 = src
__strncpy_from_user_asm:
	lghi	%r0,0
	lgr	%r1,%r4
	la	%r2,0(%r2,%r4)	# %r2 points to first byte after string
	sacf	256
0:	srst	%r2,%r1
	jo	0b
	sacf	0
	lgr	%r1,%r2
	jh	1f		# \0 found in string ?
	aghi	%r1,1		# include \0 in copy
1:	slgr	%r1,%r4		# %r1 = copy length (without \0)
	slgr	%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)
	aghi	%r1,-256
	mvcp	0(%r1,%r3),0(%r4),%r0
	jnz	3b
	br	%r14
4:	sacf	0
	lghi	%r2,-EFAULT
	br	%r14
	.section __ex_table,"a"
	.quad	0b,4b
	.previous

        .align 4
        .text
        .globl __strnlen_user_asm
	# %r2 = count, %r3 = src
__strnlen_user_asm:
	lghi	%r0,0
	lgr	%r1,%r3
	la	%r2,0(%r2,%r3)	# %r2 points to first byte after string
	sacf	256
0:	srst	%r2,%r1
	jo	0b
	sacf	0
	aghi	%r2,1		# strnlen_user result includes the \0
				# or return count+1 if \0 not found
	slgr	%r2,%r3
	br	%r14
2:	sacf	0
	slgr	%r2,%r2		# return 0 on exception
	br	%r14
	.section __ex_table,"a"
	.quad	0b,2b
	.previous