xref: /linux/arch/parisc/lib/lusercopy.S (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e)
1/*
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#include <linux/linkage.h>
41
42	/*
43	 * get_sr gets the appropriate space value into
44	 * sr1 for kernel/user space access, depending
45	 * on the flag stored in the task structure.
46	 */
47
48	.macro  get_sr
49	mfctl       %cr30,%r1
50	ldw         TI_SEGMENT(%r1),%r22
51	mfsp        %sr3,%r1
52	or,<>       %r22,%r0,%r0
53	copy        %r0,%r1
54	mtsp        %r1,%sr1
55	.endm
56
57	.macro fixup_branch lbl
58	ldil	    L%\lbl, %r1
59	ldo	    R%\lbl(%r1), %r1
60	bv          %r0(%r1)
61	.endm
62
63	/*
64	 * unsigned long lclear_user(void *to, unsigned long n)
65	 *
66	 * Returns 0 for success.
67	 * otherwise, returns number of bytes not transferred.
68	 */
69
70ENTRY(lclear_user)
71	.proc
72	.callinfo NO_CALLS
73	.entry
74	comib,=,n   0,%r25,$lclu_done
75	get_sr
76$lclu_loop:
77	addib,<>    -1,%r25,$lclu_loop
781:      stbs,ma     %r0,1(%sr1,%r26)
79
80$lclu_done:
81	bv          %r0(%r2)
82	copy        %r25,%r28
83	.exit
84ENDPROC(lclear_user)
85
86	.section .fixup,"ax"
872:      fixup_branch $lclu_done
88	ldo        1(%r25),%r25
89	.previous
90
91	.section __ex_table,"aw"
92	ASM_ULONG_INSN 1b,2b
93	.previous
94
95	.procend
96
97	/*
98	 * long lstrnlen_user(char *s, long n)
99	 *
100	 * Returns 0 if exception before zero byte or reaching N,
101	 *         N+1 if N would be exceeded,
102	 *         else strlen + 1 (i.e. includes zero byte).
103	 */
104
105ENTRY(lstrnlen_user)
106	.proc
107	.callinfo NO_CALLS
108	.entry
109	comib,=     0,%r25,$lslen_nzero
110	copy	    %r26,%r24
111	get_sr
1121:      ldbs,ma     1(%sr1,%r26),%r1
113$lslen_loop:
114	comib,=,n   0,%r1,$lslen_done
115	addib,<>    -1,%r25,$lslen_loop
1162:      ldbs,ma     1(%sr1,%r26),%r1
117$lslen_done:
118	bv          %r0(%r2)
119	sub	    %r26,%r24,%r28
120	.exit
121
122$lslen_nzero:
123	b           $lslen_done
124	ldo         1(%r26),%r26 /* special case for N == 0 */
125ENDPROC(lstrnlen_user)
126
127	.section .fixup,"ax"
1283:      fixup_branch $lslen_done
129	copy        %r24,%r26    /* reset r26 so 0 is returned on fault */
130	.previous
131
132	.section __ex_table,"aw"
133	ASM_ULONG_INSN 1b,3b
134	ASM_ULONG_INSN 2b,3b
135	.previous
136
137	.procend
138
139	.end
140