tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * linux/arch/arm26/lib/uaccess-kernel.S
3 *
4 * Copyright (C) 1998 Russell King
5 *
6 * Note! Some code fragments found in here have a special calling
7 * convention - they are not APCS compliant!
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13#include <linux/linkage.h>
14#include <asm/assembler.h>
15
16 .text
17
18//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)
19
20 .globl uaccess_kernel
21uaccess_kernel:
22 .word uaccess_kernel_put_byte
23 .word uaccess_kernel_get_byte
24 .word uaccess_kernel_put_half
25 .word uaccess_kernel_get_half
26 .word uaccess_kernel_put_word
27 .word uaccess_kernel_get_word
28 .word uaccess_kernel_put_dword
29 .word uaccess_kernel_copy
30 .word uaccess_kernel_copy
31 .word uaccess_kernel_clear
32 .word uaccess_kernel_strncpy
33 .word uaccess_kernel_strnlen
34
35@ In : r0 = x, r1 = addr, r2 = error
36@ Out: r2 = error
37uaccess_kernel_put_byte:
38 stmfd sp!, {lr}
39 strb r0, [r1]
40 ldmfd sp!, {pc}^
41
42@ In : r0 = x, r1 = addr, r2 = error
43@ Out: r2 = error
44uaccess_kernel_put_half:
45 stmfd sp!, {lr}
46 strb r0, [r1]
47 mov r0, r0, lsr #8
48 strb r0, [r1, #1]
49 ldmfd sp!, {pc}^
50
51@ In : r0 = x, r1 = addr, r2 = error
52@ Out: r2 = error
53uaccess_kernel_put_word:
54 stmfd sp!, {lr}
55 str r0, [r1]
56 ldmfd sp!, {pc}^
57
58@ In : r0 = x, r1 = addr, r2 = error
59@ Out: r2 = error
60uaccess_kernel_put_dword:
61 stmfd sp!, {lr}
62 str r0, [r1], #4
63 str r0, [r1], #0
64 ldmfd sp!, {pc}^
65
66@ In : r0 = addr, r1 = error
67@ Out: r0 = x, r1 = error
68uaccess_kernel_get_byte:
69 stmfd sp!, {lr}
70 ldrb r0, [r0]
71 ldmfd sp!, {pc}^
72
73@ In : r0 = addr, r1 = error
74@ Out: r0 = x, r1 = error
75uaccess_kernel_get_half:
76 stmfd sp!, {lr}
77 ldr r0, [r0]
78 mov r0, r0, lsl #16
79 mov r0, r0, lsr #16
80 ldmfd sp!, {pc}^
81
82@ In : r0 = addr, r1 = error
83@ Out: r0 = x, r1 = error
84uaccess_kernel_get_word:
85 stmfd sp!, {lr}
86 ldr r0, [r0]
87 ldmfd sp!, {pc}^
88
89
90/* Prototype: int uaccess_kernel_copy(void *to, const char *from, size_t n)
91 * Purpose : copy a block to kernel memory from kernel memory
92 * Params : to - kernel memory
93 * : from - kernel memory
94 * : n - number of bytes to copy
95 * Returns : Number of bytes NOT copied.
96 */
97uaccess_kernel_copy:
98 stmfd sp!, {lr}
99 bl memcpy
100 mov r0, #0
101 ldmfd sp!, {pc}^
102
103/* Prototype: int uaccess_kernel_clear(void *addr, size_t sz)
104 * Purpose : clear some kernel memory
105 * Params : addr - kernel memory address to clear
106 * : sz - number of bytes to clear
107 * Returns : number of bytes NOT cleared
108 */
109uaccess_kernel_clear:
110 stmfd sp!, {lr}
111 mov r2, #0
112 cmp r1, #4
113 blt 2f
114 ands ip, r0, #3
115 beq 1f
116 cmp ip, #1
117 strb r2, [r0], #1
118 strleb r2, [r0], #1
119 strltb r2, [r0], #1
120 rsb ip, ip, #4
121 sub r1, r1, ip @ 7 6 5 4 3 2 1
1221: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
123 bmi 2f
124 str r2, [r0], #4
125 str r2, [r0], #4
126 b 1b
1272: adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3
128 strpl r2, [r0], #4
129 tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
130 strneb r2, [r0], #1
131 strneb r2, [r0], #1
132 tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1
133 strneb r2, [r0], #1
134 mov r0, #0
135 ldmfd sp!, {pc}^
136
137/* Prototype: size_t uaccess_kernel_strncpy(char *dst, char *src, size_t len)
138 * Purpose : copy a string from kernel memory to kernel memory
139 * Params : dst - kernel memory destination
140 * : src - kernel memory source
141 * : len - maximum length of string
142 * Returns : number of characters copied
143 */
144uaccess_kernel_strncpy:
145 stmfd sp!, {lr}
146 mov ip, r2
1471: subs r2, r2, #1
148 bmi 2f
149 ldrb r3, [r1], #1
150 strb r3, [r0], #1
151 teq r3, #0
152 bne 1b
1532: subs r0, ip, r2
154 ldmfd sp!, {pc}^
155
156/* Prototype: int uaccess_kernel_strlen(char *str, long n)
157 * Purpose : get length of a string in kernel memory
158 * Params : str - address of string in kernel memory
159 * Returns : length of string *including terminator*,
160 * or zero on exception, or n + 1 if too long
161 */
162uaccess_kernel_strnlen:
163 stmfd sp!, {lr}
164 mov r2, r0
1651: ldrb r1, [r0], #1
166 teq r1, #0
167 beq 2f
168 subs r1, r1, #1
169 bne 1b
170 add r0, r0, #1
1712: sub r0, r0, r2
172 ldmfd sp!, {pc}^
173