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	 * long lstrncpy_from_user(char *dst, const char *src, long n)
65	 *
66	 * Returns -EFAULT if exception before terminator,
67	 *         N if the entire buffer filled,
68	 *         otherwise strlen (i.e. excludes zero byte)
69	 */
70
71ENTRY(lstrncpy_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
90ENDPROC(lstrncpy_from_user)
91
92	.section .fixup,"ax"
933:      fixup_branch $lsfu_exit
94	ldi         -EFAULT,%r28
95	.previous
96
97	.section __ex_table,"aw"
98	ASM_ULONG_INSN 1b,3b
99	ASM_ULONG_INSN 2b,3b
100	.previous
101
102	.procend
103
104	/*
105	 * unsigned long lclear_user(void *to, unsigned long n)
106	 *
107	 * Returns 0 for success.
108	 * otherwise, returns number of bytes not transferred.
109	 */
110
111ENTRY(lclear_user)
112	.proc
113	.callinfo NO_CALLS
114	.entry
115	comib,=,n   0,%r25,$lclu_done
116	get_sr
117$lclu_loop:
118	addib,<>    -1,%r25,$lclu_loop
1191:      stbs,ma     %r0,1(%sr1,%r26)
120
121$lclu_done:
122	bv          %r0(%r2)
123	copy        %r25,%r28
124	.exit
125ENDPROC(lclear_user)
126
127	.section .fixup,"ax"
1282:      fixup_branch $lclu_done
129	ldo        1(%r25),%r25
130	.previous
131
132	.section __ex_table,"aw"
133	ASM_ULONG_INSN 1b,2b
134	.previous
135
136	.procend
137
138	/*
139	 * long lstrnlen_user(char *s, long n)
140	 *
141	 * Returns 0 if exception before zero byte or reaching N,
142	 *         N+1 if N would be exceeded,
143	 *         else strlen + 1 (i.e. includes zero byte).
144	 */
145
146ENTRY(lstrnlen_user)
147	.proc
148	.callinfo NO_CALLS
149	.entry
150	comib,=     0,%r25,$lslen_nzero
151	copy	    %r26,%r24
152	get_sr
1531:      ldbs,ma     1(%sr1,%r26),%r1
154$lslen_loop:
155	comib,=,n   0,%r1,$lslen_done
156	addib,<>    -1,%r25,$lslen_loop
1572:      ldbs,ma     1(%sr1,%r26),%r1
158$lslen_done:
159	bv          %r0(%r2)
160	sub	    %r26,%r24,%r28
161	.exit
162
163$lslen_nzero:
164	b           $lslen_done
165	ldo         1(%r26),%r26 /* special case for N == 0 */
166ENDPROC(lstrnlen_user)
167
168	.section .fixup,"ax"
1693:      fixup_branch $lslen_done
170	copy        %r24,%r26    /* reset r26 so 0 is returned on fault */
171	.previous
172
173	.section __ex_table,"aw"
174	ASM_ULONG_INSN 1b,3b
175	ASM_ULONG_INSN 2b,3b
176	.previous
177
178	.procend
179
180	.end
181