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75494230 NP |
1 | /* |
2 | * linux/arch/arm/lib/copy_template.s | |
3 | * | |
4 | * Code template for optimized memory copy functions | |
5 | * | |
6 | * Author: Nicolas Pitre | |
7 | * Created: Sep 28, 2005 | |
8 | * Copyright: MontaVista Software, Inc. | |
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 version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | */ | |
14 | ||
15 | /* | |
16 | * This can be used to enable code to cacheline align the source pointer. | |
17 | * Experiments on tested architectures (StrongARM and XScale) didn't show | |
18 | * this a worthwhile thing to do. That might be different in the future. | |
19 | */ | |
20 | //#define CALGN(code...) code | |
21 | #define CALGN(code...) | |
22 | ||
23 | /* | |
24 | * Theory of operation | |
25 | * ------------------- | |
26 | * | |
27 | * This file provides the core code for a forward memory copy used in | |
28 | * the implementation of memcopy(), copy_to_user() and copy_from_user(). | |
29 | * | |
30 | * The including file must define the following accessor macros | |
31 | * according to the need of the given function: | |
32 | * | |
33 | * ldr1w ptr reg abort | |
34 | * | |
35 | * This loads one word from 'ptr', stores it in 'reg' and increments | |
36 | * 'ptr' to the next word. The 'abort' argument is used for fixup tables. | |
37 | * | |
38 | * ldr4w ptr reg1 reg2 reg3 reg4 abort | |
39 | * ldr8w ptr, reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort | |
40 | * | |
41 | * This loads four or eight words starting from 'ptr', stores them | |
42 | * in provided registers and increments 'ptr' past those words. | |
43 | * The'abort' argument is used for fixup tables. | |
44 | * | |
45 | * ldr1b ptr reg cond abort | |
46 | * | |
47 | * Similar to ldr1w, but it loads a byte and increments 'ptr' one byte. | |
48 | * It also must apply the condition code if provided, otherwise the | |
49 | * "al" condition is assumed by default. | |
50 | * | |
51 | * str1w ptr reg abort | |
52 | * str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort | |
53 | * str1b ptr reg cond abort | |
54 | * | |
55 | * Same as their ldr* counterparts, but data is stored to 'ptr' location | |
56 | * rather than being loaded. | |
57 | * | |
58 | * enter reg1 reg2 | |
59 | * | |
60 | * Preserve the provided registers on the stack plus any additional | |
61 | * data as needed by the implementation including this code. Called | |
62 | * upon code entry. | |
63 | * | |
64 | * exit reg1 reg2 | |
65 | * | |
66 | * Restore registers with the values previously saved with the | |
67 | * 'preserv' macro. Called upon code termination. | |
68 | */ | |
69 | ||
70 | ||
71 | enter r4, lr | |
72 | ||
73 | subs r2, r2, #4 | |
74 | blt 8f | |
75 | ands ip, r0, #3 | |
76 | PLD( pld [r1, #0] ) | |
77 | bne 9f | |
78 | ands ip, r1, #3 | |
79 | bne 10f | |
80 | ||
81 | 1: subs r2, r2, #(28) | |
82 | stmfd sp!, {r5 - r8} | |
83 | blt 5f | |
84 | ||
85 | CALGN( ands ip, r1, #31 ) | |
86 | CALGN( rsb r3, ip, #32 ) | |
87 | CALGN( sbcnes r4, r3, r2 ) @ C is always set here | |
88 | CALGN( bcs 2f ) | |
89 | CALGN( adr r4, 6f ) | |
90 | CALGN( subs r2, r2, r3 ) @ C gets set | |
91 | CALGN( add pc, r4, ip ) | |
92 | ||
93 | PLD( pld [r1, #0] ) | |
94 | 2: PLD( subs r2, r2, #96 ) | |
95 | PLD( pld [r1, #28] ) | |
96 | PLD( blt 4f ) | |
97 | PLD( pld [r1, #60] ) | |
98 | PLD( pld [r1, #92] ) | |
99 | ||
100 | 3: PLD( pld [r1, #124] ) | |
101 | 4: ldr8w r1, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f | |
102 | subs r2, r2, #32 | |
103 | str8w r0, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f | |
104 | bge 3b | |
105 | PLD( cmn r2, #96 ) | |
106 | PLD( bge 4b ) | |
107 | ||
108 | 5: ands ip, r2, #28 | |
109 | rsb ip, ip, #32 | |
110 | addne pc, pc, ip @ C is always clear here | |
111 | b 7f | |
112 | 6: nop | |
113 | ldr1w r1, r3, abort=20f | |
114 | ldr1w r1, r4, abort=20f | |
115 | ldr1w r1, r5, abort=20f | |
116 | ldr1w r1, r6, abort=20f | |
117 | ldr1w r1, r7, abort=20f | |
118 | ldr1w r1, r8, abort=20f | |
119 | ldr1w r1, lr, abort=20f | |
120 | ||
121 | add pc, pc, ip | |
122 | nop | |
123 | nop | |
124 | str1w r0, r3, abort=20f | |
125 | str1w r0, r4, abort=20f | |
126 | str1w r0, r5, abort=20f | |
127 | str1w r0, r6, abort=20f | |
128 | str1w r0, r7, abort=20f | |
129 | str1w r0, r8, abort=20f | |
130 | str1w r0, lr, abort=20f | |
131 | ||
132 | CALGN( bcs 2b ) | |
133 | ||
134 | 7: ldmfd sp!, {r5 - r8} | |
135 | ||
136 | 8: movs r2, r2, lsl #31 | |
137 | ldr1b r1, r3, ne, abort=21f | |
138 | ldr1b r1, r4, cs, abort=21f | |
139 | ldr1b r1, ip, cs, abort=21f | |
140 | str1b r0, r3, ne, abort=21f | |
141 | str1b r0, r4, cs, abort=21f | |
142 | str1b r0, ip, cs, abort=21f | |
143 | ||
144 | exit r4, pc | |
145 | ||
146 | 9: rsb ip, ip, #4 | |
147 | cmp ip, #2 | |
148 | ldr1b r1, r3, gt, abort=21f | |
149 | ldr1b r1, r4, ge, abort=21f | |
150 | ldr1b r1, lr, abort=21f | |
151 | str1b r0, r3, gt, abort=21f | |
152 | str1b r0, r4, ge, abort=21f | |
153 | subs r2, r2, ip | |
154 | str1b r0, lr, abort=21f | |
155 | blt 8b | |
156 | ands ip, r1, #3 | |
157 | beq 1b | |
158 | ||
159 | 10: bic r1, r1, #3 | |
160 | cmp ip, #2 | |
161 | ldr1w r1, lr, abort=21f | |
162 | beq 17f | |
163 | bgt 18f | |
164 | ||
165 | ||
166 | .macro forward_copy_shift pull push | |
167 | ||
168 | subs r2, r2, #28 | |
169 | blt 14f | |
170 | ||
171 | CALGN( ands ip, r1, #31 ) | |
172 | CALGN( rsb ip, ip, #32 ) | |
173 | CALGN( sbcnes r4, ip, r2 ) @ C is always set here | |
174 | CALGN( subcc r2, r2, ip ) | |
175 | CALGN( bcc 15f ) | |
176 | ||
177 | 11: stmfd sp!, {r5 - r9} | |
178 | ||
179 | PLD( pld [r1, #0] ) | |
180 | PLD( subs r2, r2, #96 ) | |
181 | PLD( pld [r1, #28] ) | |
182 | PLD( blt 13f ) | |
183 | PLD( pld [r1, #60] ) | |
184 | PLD( pld [r1, #92] ) | |
185 | ||
186 | 12: PLD( pld [r1, #124] ) | |
187 | 13: ldr4w r1, r4, r5, r6, r7, abort=19f | |
188 | mov r3, lr, pull #\pull | |
189 | subs r2, r2, #32 | |
190 | ldr4w r1, r8, r9, ip, lr, abort=19f | |
191 | orr r3, r3, r4, push #\push | |
192 | mov r4, r4, pull #\pull | |
193 | orr r4, r4, r5, push #\push | |
194 | mov r5, r5, pull #\pull | |
195 | orr r5, r5, r6, push #\push | |
196 | mov r6, r6, pull #\pull | |
197 | orr r6, r6, r7, push #\push | |
198 | mov r7, r7, pull #\pull | |
199 | orr r7, r7, r8, push #\push | |
200 | mov r8, r8, pull #\pull | |
201 | orr r8, r8, r9, push #\push | |
202 | mov r9, r9, pull #\pull | |
203 | orr r9, r9, ip, push #\push | |
204 | mov ip, ip, pull #\pull | |
205 | orr ip, ip, lr, push #\push | |
206 | str8w r0, r3, r4, r5, r6, r7, r8, r9, ip, , abort=19f | |
207 | bge 12b | |
208 | PLD( cmn r2, #96 ) | |
209 | PLD( bge 13b ) | |
210 | ||
211 | ldmfd sp!, {r5 - r9} | |
212 | ||
213 | 14: ands ip, r2, #28 | |
214 | beq 16f | |
215 | ||
216 | 15: mov r3, lr, pull #\pull | |
217 | ldr1w r1, lr, abort=21f | |
218 | subs ip, ip, #4 | |
219 | orr r3, r3, lr, push #\push | |
220 | str1w r0, r3, abort=21f | |
221 | bgt 15b | |
222 | CALGN( cmp r2, #0 ) | |
223 | CALGN( bge 11b ) | |
224 | ||
225 | 16: sub r1, r1, #(\push / 8) | |
226 | b 8b | |
227 | ||
228 | .endm | |
229 | ||
230 | ||
231 | forward_copy_shift pull=8 push=24 | |
232 | ||
233 | 17: forward_copy_shift pull=16 push=16 | |
234 | ||
235 | 18: forward_copy_shift pull=24 push=8 | |
236 | ||
237 | ||
238 | /* | |
239 | * Abort preanble and completion macros. | |
240 | * If a fixup handler is required then those macros must surround it. | |
241 | * It is assumed that the fixup code will handle the private part of | |
242 | * the exit macro. | |
243 | */ | |
244 | ||
245 | .macro copy_abort_preamble | |
246 | 19: ldmfd sp!, {r5 - r9} | |
247 | b 21f | |
248 | 20: ldmfd sp!, {r5 - r8} | |
249 | 21: | |
250 | .endm | |
251 | ||
252 | .macro copy_abort_end | |
253 | ldmfd sp!, {r4, pc} | |
254 | .endm | |
255 |