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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * User Space Access Routines
3 *
4 * Copyright (C) 2000-2002 Hewlett-Packard (John Marvin)
5 * Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
6 * Copyright (C) 2001 Matthieu Delahaye <delahaym at esiee.fr>
7 * Copyright (C) 2003 Randolph Chung <tausq with parisc-linux.org>
8 *
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2, or (at your option)
13 * any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 */
24
25/*
26 * These routines still have plenty of room for optimization
27 * (word & doubleword load/store, dual issue, store hints, etc.).
28 */
29
30/*
31 * The following routines assume that space register 3 (sr3) contains
32 * the space id associated with the current users address space.
33 */
34
35
36 .text
37
38#include <asm/assembly.h>
39#include <asm/errno.h>
40
41 /*
42 * get_sr gets the appropriate space value into
43 * sr1 for kernel/user space access, depending
44 * on the flag stored in the task structure.
45 */
46
47 .macro get_sr
48 mfctl %cr30,%r1
49 ldw TI_SEGMENT(%r1),%r22
50 mfsp %sr3,%r1
51 or,<> %r22,%r0,%r0
52 copy %r0,%r1
53 mtsp %r1,%sr1
54 .endm
55
56 .macro fixup_branch lbl
57 ldil L%\lbl, %r1
58 ldo R%\lbl(%r1), %r1
59 bv %r0(%r1)
60 .endm
61
62 /*
63 * long lstrncpy_from_user(char *dst, const char *src, long n)
64 *
65 * Returns -EFAULT if exception before terminator,
66 * N if the entire buffer filled,
67 * otherwise strlen (i.e. excludes zero byte)
68 */
69
70 .export lstrncpy_from_user,code
71lstrncpy_from_user:
72 .proc
73 .callinfo NO_CALLS
74 .entry
75 comib,= 0,%r24,$lsfu_done
76 copy %r24,%r23
77 get_sr
781: ldbs,ma 1(%sr1,%r25),%r1
79$lsfu_loop:
80 stbs,ma %r1,1(%r26)
81 comib,=,n 0,%r1,$lsfu_done
82 addib,<>,n -1,%r24,$lsfu_loop
832: ldbs,ma 1(%sr1,%r25),%r1
84$lsfu_done:
85 sub %r23,%r24,%r28
86$lsfu_exit:
87 bv %r0(%r2)
88 nop
89 .exit
90
91 .section .fixup,"ax"
923: fixup_branch $lsfu_exit
93 ldi -EFAULT,%r28
94 .previous
95
96 .section __ex_table,"aw"
97#ifdef __LP64__
98 .dword 1b,3b
99 .dword 2b,3b
100#else
101 .word 1b,3b
102 .word 2b,3b
103#endif
104 .previous
105
106 .procend
107
108 /*
109 * unsigned long lclear_user(void *to, unsigned long n)
110 *
111 * Returns 0 for success.
112 * otherwise, returns number of bytes not transferred.
113 */
114
115 .export lclear_user,code
116lclear_user:
117 .proc
118 .callinfo NO_CALLS
119 .entry
120 comib,=,n 0,%r25,$lclu_done
121 get_sr
122$lclu_loop:
123 addib,<> -1,%r25,$lclu_loop
1241: stbs,ma %r0,1(%sr1,%r26)
125
126$lclu_done:
127 bv %r0(%r2)
128 copy %r25,%r28
129 .exit
130
131 .section .fixup,"ax"
1322: fixup_branch $lclu_done
133 ldo 1(%r25),%r25
134 .previous
135
136 .section __ex_table,"aw"
137#ifdef __LP64__
138 .dword 1b,2b
139#else
140 .word 1b,2b
141#endif
142 .previous
143
144 .procend
145
146 /*
147 * long lstrnlen_user(char *s, long n)
148 *
149 * Returns 0 if exception before zero byte or reaching N,
150 * N+1 if N would be exceeded,
151 * else strlen + 1 (i.e. includes zero byte).
152 */
153
154 .export lstrnlen_user,code
155lstrnlen_user:
156 .proc
157 .callinfo NO_CALLS
158 .entry
159 comib,= 0,%r25,$lslen_nzero
160 copy %r26,%r24
161 get_sr
1621: ldbs,ma 1(%sr1,%r26),%r1
163$lslen_loop:
164 comib,=,n 0,%r1,$lslen_done
165 addib,<> -1,%r25,$lslen_loop
1662: ldbs,ma 1(%sr1,%r26),%r1
167$lslen_done:
168 bv %r0(%r2)
169 sub %r26,%r24,%r28
170 .exit
171
172$lslen_nzero:
173 b $lslen_done
174 ldo 1(%r26),%r26 /* special case for N == 0 */
175
176 .section .fixup,"ax"
1773: fixup_branch $lslen_done
178 copy %r24,%r26 /* reset r26 so 0 is returned on fault */
179 .previous
180
181 .section __ex_table,"aw"
182#ifdef __LP64__
183 .dword 1b,3b
184 .dword 2b,3b
185#else
186 .word 1b,3b
187 .word 2b,3b
188#endif
189 .previous
190
191 .procend
192
193 .end