1 /*
2 * arch/xtensa/lib/strncpy_user.S
3 *
4 * This file is subject to the terms and cond
5 * Public License. See the file "COPYING" in
6 * this archive for more details.
7 *
8 * Returns: -EFAULT if exception before termi
9 * buffer filled, else strlen.
10 *
11 * Copyright (C) 2002 Tensilica Inc.
12 */
13
14 #include <linux/errno.h>
15 #include <linux/linkage.h>
16 #include <asm/asmmacro.h>
17 #include <asm/core.h>
18
19 /*
20 * char *__strncpy_user(char *dst, const char
21 */
22
23 #ifdef __XTENSA_EB__
24 # define MASK0 0xff000000
25 # define MASK1 0x00ff0000
26 # define MASK2 0x0000ff00
27 # define MASK3 0x000000ff
28 #else
29 # define MASK0 0x000000ff
30 # define MASK1 0x0000ff00
31 # define MASK2 0x00ff0000
32 # define MASK3 0xff000000
33 #endif
34
35 # Register use
36 # a0/ return address
37 # a1/ stack pointer
38 # a2/ return value
39 # a3/ src
40 # a4/ len
41 # a5/ mask0
42 # a6/ mask1
43 # a7/ mask2
44 # a8/ mask3
45 # a9/ tmp
46 # a10/ tmp
47 # a11/ dst
48
49 .text
50 ENTRY(__strncpy_user)
51
52 abi_entry_default
53 # a2/ dst, a3/ src, a4/ len
54 mov a11, a2 # leave dst in
55 beqz a4, .Lret # if len is ze
56 movi a5, MASK0 # mask for byt
57 movi a6, MASK1 # mask for byt
58 movi a7, MASK2 # mask for byt
59 movi a8, MASK3 # mask for byt
60 bbsi.l a3, 0, .Lsrc1mod2 # if only 8
61 bbsi.l a3, 1, .Lsrc2mod4 # if only 16
62 .Lsrcaligned: # return here when src is word
63 srli a10, a4, 2 # number of lo
64 movi a9, 3
65 bnone a11, a9, .Laligned
66 j .Ldstunaligned
67
68 .Lsrc1mod2: # src address is odd
69 EX(11f) l8ui a9, a3, 0 # get
70 addi a3, a3, 1 # adva
71 EX(10f) s8i a9, a11, 0 # stor
72 beqz a9, .Lret # if b
73 addi a11, a11, 1 # adva
74 addi a4, a4, -1 # decr
75 beqz a4, .Lret # if l
76 bbci.l a3, 1, .Lsrcaligned # if s
77
78 .Lsrc2mod4: # src address is 2 mod 4
79 EX(11f) l8ui a9, a3, 0 # get
80 /* 1-cycle interlock */
81 EX(10f) s8i a9, a11, 0 # stor
82 beqz a9, .Lret # if b
83 addi a11, a11, 1 # adva
84 addi a4, a4, -1 # decr
85 beqz a4, .Lret # if l
86 EX(11f) l8ui a9, a3, 1 # get
87 addi a3, a3, 2 # adva
88 EX(10f) s8i a9, a11, 0 # stor
89 beqz a9, .Lret # if b
90 addi a11, a11, 1 # adva
91 addi a4, a4, -1 # decr
92 bnez a4, .Lsrcaligned # if l
93 .Lret:
94 sub a2, a11, a2 # comp
95 abi_ret_default
96
97 /*
98 * dst is word-aligned, src is word-aligned
99 */
100 .align 4 # 1 mod 4 alig
101 .byte 0 # (0 mod 4 ali
102 .Laligned:
103 #if XCHAL_HAVE_LOOPS
104 loopnez a10, .Loop1done
105 #else
106 beqz a10, .Loop1done
107 slli a10, a10, 2
108 add a10, a10, a11 # a10 = end of
109 #endif
110 .Loop1:
111 EX(11f) l32i a9, a3, 0 # get
112 addi a3, a3, 4 # adva
113 bnone a9, a5, .Lz0 # if b
114 bnone a9, a6, .Lz1 # if b
115 bnone a9, a7, .Lz2 # if b
116 EX(10f) s32i a9, a11, 0 # stor
117 bnone a9, a8, .Lz3 # if b
118 addi a11, a11, 4 # adva
119 #if !XCHAL_HAVE_LOOPS
120 blt a11, a10, .Loop1
121 #endif
122
123 .Loop1done:
124 bbci.l a4, 1, .L100
125 # copy 2 bytes
126 EX(11f) l16ui a9, a3, 0
127 addi a3, a3, 2 # adva
128 #ifdef __XTENSA_EB__
129 bnone a9, a7, .Lz0 # if b
130 bnone a9, a8, .Lz1 # if b
131 #else
132 bnone a9, a5, .Lz0 # if b
133 bnone a9, a6, .Lz1 # if b
134 #endif
135 EX(10f) s16i a9, a11, 0
136 addi a11, a11, 2 # adva
137 .L100:
138 bbci.l a4, 0, .Lret
139 EX(11f) l8ui a9, a3, 0
140 /* slot */
141 EX(10f) s8i a9, a11, 0
142 beqz a9, .Lret # if b
143 addi a11, a11, 1-3 # adva
144 # the
145 /* fall thru to .Lz3 and "retw" */
146
147 .Lz3: # byte 3 is zero
148 addi a11, a11, 3 # adva
149 sub a2, a11, a2 # comp
150 abi_ret_default
151 .Lz0: # byte 0 is zero
152 #ifdef __XTENSA_EB__
153 movi a9, 0
154 #endif /* __XTENSA_EB__ */
155 EX(10f) s8i a9, a11, 0
156 sub a2, a11, a2 # comp
157 abi_ret_default
158 .Lz1: # byte 1 is zero
159 #ifdef __XTENSA_EB__
160 extui a9, a9, 16, 16
161 #endif /* __XTENSA_EB__ */
162 EX(10f) s16i a9, a11, 0
163 addi a11, a11, 1 # adva
164 sub a2, a11, a2 # comp
165 abi_ret_default
166 .Lz2: # byte 2 is zero
167 #ifdef __XTENSA_EB__
168 extui a9, a9, 16, 16
169 #endif /* __XTENSA_EB__ */
170 EX(10f) s16i a9, a11, 0
171 movi a9, 0
172 EX(10f) s8i a9, a11, 2
173 addi a11, a11, 2 # adva
174 sub a2, a11, a2 # comp
175 abi_ret_default
176
177 .align 4 # 1 mod 4 alig
178 .byte 0 # (0 mod 4 ali
179 .Ldstunaligned:
180 /*
181 * for now just use byte copy loop
182 */
183 #if XCHAL_HAVE_LOOPS
184 loopnez a4, .Lunalignedend
185 #else
186 beqz a4, .Lunalignedend
187 add a10, a11, a4 # a10
188 #endif /* XCHAL_HAVE_LOOPS */
189 .Lnextbyte:
190 EX(11f) l8ui a9, a3, 0
191 addi a3, a3, 1
192 EX(10f) s8i a9, a11, 0
193 beqz a9, .Lunalignedend
194 addi a11, a11, 1
195 #if !XCHAL_HAVE_LOOPS
196 blt a11, a10, .Lnextbyte
197 #endif
198
199 .Lunalignedend:
200 sub a2, a11, a2 # comp
201 abi_ret_default
202
203 ENDPROC(__strncpy_user)
204 EXPORT_SYMBOL(__strncpy_user)
205
206 .section .fixup, "ax"
207 .align 4
208
209 /* For now, just return -EFAULT. Futu
210 * like to clear remaining kernel spac
211 * implementation in memset(). Thus,
212 * load/store fixups. */
213
214 10:
215 11:
216 movi a2, -EFAULT
217 abi_ret_default
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