summaryrefslogtreecommitdiff
path: root/arch/sh/lib/clear_page.S
blob: 8342bfbde64c23a1f1128785b1ed810ba4f46b86 (plain)
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
/*
 * __clear_user_page, __clear_user, clear_page implementation of SuperH
 *
 * Copyright (C) 2001  Kaz Kojima
 * Copyright (C) 2001, 2002  Niibe Yutaka
 * Copyright (C) 2006  Paul Mundt
 */
#include <linux/linkage.h>
#include <asm/page.h>

/*
 * clear_page
 * @to: P1 address
 *
 * void clear_page(void *to)
 */

/*
 * r0 --- scratch
 * r4 --- to
 * r5 --- to + PAGE_SIZE
 */
ENTRY(clear_page)
	mov	r4,r5
	mov.l	.Llimit,r0
	add	r0,r5
	mov	#0,r0
	!
1:
#if defined(CONFIG_CPU_SH4)
	movca.l	r0,@r4
	mov	r4,r1
#else
	mov.l	r0,@r4
#endif
	add	#32,r4
	mov.l	r0,@-r4
	mov.l	r0,@-r4
	mov.l	r0,@-r4
	mov.l	r0,@-r4
	mov.l	r0,@-r4
	mov.l	r0,@-r4
	mov.l	r0,@-r4
#if defined(CONFIG_CPU_SH4)
	ocbwb	@r1
#endif
	cmp/eq	r5,r4
	bf/s	1b
	 add	#28,r4
	!
	rts
	 nop

	.balign 4
.Llimit:	.long	(PAGE_SIZE-28)

ENTRY(__clear_user)
	!
	mov	#0, r0
	mov	#0xe0, r1	! 0xffffffe0
	!
	! r4..(r4+31)&~32 	   -------- not aligned	[ Area 0 ]
	! (r4+31)&~32..(r4+r5)&~32 -------- aligned	[ Area 1 ]
	! (r4+r5)&~32..r4+r5       -------- not aligned	[ Area 2 ]
	!
	! Clear area 0
	mov	r4, r2
	!
	tst	r1, r5		! length < 32
	bt	.Larea2		! skip to remainder
	!
	add	#31, r2
	and	r1, r2
	cmp/eq	r4, r2
	bt	.Larea1
	mov	r2, r3
	sub	r4, r3
	mov	r3, r7
	mov	r4, r2
	!
.L0:	dt	r3
0:	mov.b	r0, @r2
	bf/s	.L0
	 add	#1, r2
	!
	sub	r7, r5
	mov	r2, r4
.Larea1:
	mov	r4, r3
	add	r5, r3
	and	r1, r3
	cmp/hi	r2, r3
	bf	.Larea2
	!
	! Clear area 1
#if defined(CONFIG_CPU_SH4)
1:	movca.l	r0, @r2
#else
1:	mov.l	r0, @r2
#endif
	add	#4, r2
2:	mov.l	r0, @r2
	add	#4, r2
3:	mov.l	r0, @r2
	add	#4, r2
4:	mov.l	r0, @r2
	add	#4, r2
5:	mov.l	r0, @r2
	add	#4, r2
6:	mov.l	r0, @r2
	add	#4, r2
7:	mov.l	r0, @r2
	add	#4, r2
8:	mov.l	r0, @r2
	add	#4, r2
	cmp/hi	r2, r3
	bt/s	1b
	 nop
	!
	! Clear area 2
.Larea2:
	mov	r4, r3
	add	r5, r3
	cmp/hs	r3, r2
	bt/s	.Ldone
	 sub	r2, r3
.L2:	dt	r3
9:	mov.b	r0, @r2
	bf/s	.L2
	 add	#1, r2
	!
.Ldone:	rts
	 mov	#0, r0	! return 0 as normal return

	! return the number of bytes remained
.Lbad_clear_user:
	mov	r4, r0
	add	r5, r0
	rts
	 sub	r2, r0

.section __ex_table,"a"
	.align 2
	.long	0b, .Lbad_clear_user
	.long	1b, .Lbad_clear_user
	.long	2b, .Lbad_clear_user
	.long	3b, .Lbad_clear_user
	.long	4b, .Lbad_clear_user
	.long	5b, .Lbad_clear_user
	.long	6b, .Lbad_clear_user
	.long	7b, .Lbad_clear_user
	.long	8b, .Lbad_clear_user
	.long	9b, .Lbad_clear_user
.previous