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
|
/*
* linux/arch/arm26/lib/uaccess-kernel.S
*
* Copyright (C) 1998 Russell King
*
* Note! Some code fragments found in here have a special calling
* convention - they are not APCS compliant!
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
.text
//FIXME - surely this can be done in C not asm, removing the problem of keeping C and asm in sync? (this is a struct uaccess_t)
.globl uaccess_kernel
uaccess_kernel:
.word uaccess_kernel_put_byte
.word uaccess_kernel_get_byte
.word uaccess_kernel_put_half
.word uaccess_kernel_get_half
.word uaccess_kernel_put_word
.word uaccess_kernel_get_word
.word uaccess_kernel_put_dword
.word uaccess_kernel_copy
.word uaccess_kernel_copy
.word uaccess_kernel_clear
.word uaccess_kernel_strncpy
.word uaccess_kernel_strnlen
@ In : r0 = x, r1 = addr, r2 = error
@ Out: r2 = error
uaccess_kernel_put_byte:
stmfd sp!, {lr}
strb r0, [r1]
ldmfd sp!, {pc}^
@ In : r0 = x, r1 = addr, r2 = error
@ Out: r2 = error
uaccess_kernel_put_half:
stmfd sp!, {lr}
strb r0, [r1]
mov r0, r0, lsr #8
strb r0, [r1, #1]
ldmfd sp!, {pc}^
@ In : r0 = x, r1 = addr, r2 = error
@ Out: r2 = error
uaccess_kernel_put_word:
stmfd sp!, {lr}
str r0, [r1]
ldmfd sp!, {pc}^
@ In : r0 = x, r1 = addr, r2 = error
@ Out: r2 = error
uaccess_kernel_put_dword:
stmfd sp!, {lr}
str r0, [r1], #4
str r0, [r1], #0
ldmfd sp!, {pc}^
@ In : r0 = addr, r1 = error
@ Out: r0 = x, r1 = error
uaccess_kernel_get_byte:
stmfd sp!, {lr}
ldrb r0, [r0]
ldmfd sp!, {pc}^
@ In : r0 = addr, r1 = error
@ Out: r0 = x, r1 = error
uaccess_kernel_get_half:
stmfd sp!, {lr}
ldr r0, [r0]
mov r0, r0, lsl #16
mov r0, r0, lsr #16
ldmfd sp!, {pc}^
@ In : r0 = addr, r1 = error
@ Out: r0 = x, r1 = error
uaccess_kernel_get_word:
stmfd sp!, {lr}
ldr r0, [r0]
ldmfd sp!, {pc}^
/* Prototype: int uaccess_kernel_copy(void *to, const char *from, size_t n)
* Purpose : copy a block to kernel memory from kernel memory
* Params : to - kernel memory
* : from - kernel memory
* : n - number of bytes to copy
* Returns : Number of bytes NOT copied.
*/
uaccess_kernel_copy:
stmfd sp!, {lr}
bl memcpy
mov r0, #0
ldmfd sp!, {pc}^
/* Prototype: int uaccess_kernel_clear(void *addr, size_t sz)
* Purpose : clear some kernel memory
* Params : addr - kernel memory address to clear
* : sz - number of bytes to clear
* Returns : number of bytes NOT cleared
*/
uaccess_kernel_clear:
stmfd sp!, {lr}
mov r2, #0
cmp r1, #4
blt 2f
ands ip, r0, #3
beq 1f
cmp ip, #1
strb r2, [r0], #1
strleb r2, [r0], #1
strltb r2, [r0], #1
rsb ip, ip, #4
sub r1, r1, ip @ 7 6 5 4 3 2 1
1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
bmi 2f
str r2, [r0], #4
str r2, [r0], #4
b 1b
2: adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3
strpl r2, [r0], #4
tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
strneb r2, [r0], #1
strneb r2, [r0], #1
tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1
strneb r2, [r0], #1
mov r0, #0
ldmfd sp!, {pc}^
/* Prototype: size_t uaccess_kernel_strncpy(char *dst, char *src, size_t len)
* Purpose : copy a string from kernel memory to kernel memory
* Params : dst - kernel memory destination
* : src - kernel memory source
* : len - maximum length of string
* Returns : number of characters copied
*/
uaccess_kernel_strncpy:
stmfd sp!, {lr}
mov ip, r2
1: subs r2, r2, #1
bmi 2f
ldrb r3, [r1], #1
strb r3, [r0], #1
teq r3, #0
bne 1b
2: subs r0, ip, r2
ldmfd sp!, {pc}^
/* Prototype: int uaccess_kernel_strlen(char *str, long n)
* Purpose : get length of a string in kernel memory
* Params : str - address of string in kernel memory
* Returns : length of string *including terminator*,
* or zero on exception, or n + 1 if too long
*/
uaccess_kernel_strnlen:
stmfd sp!, {lr}
mov r2, r0
1: ldrb r1, [r0], #1
teq r1, #0
beq 2f
subs r1, r1, #1
bne 1b
add r0, r0, #1
2: sub r0, r0, r2
ldmfd sp!, {pc}^
|
