1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * copy_page, __copy_user_page, __copy_user implementation of SuperH
4 *
5 * Copyright (C) 2001 Niibe Yutaka & Kaz Kojima
6 * Copyright (C) 2002 Toshinobu Sugioka
7 * Copyright (C) 2006 Paul Mundt
8 */
9#include <linux/linkage.h>
10#include <asm/page.h>
11
12/*
13 * copy_page
14 * @to: P1 address
15 * @from: P1 address
16 *
17 * void copy_page(void *to, void *from)
18 */
19
20/*
21 * r0, r1, r2, r3, r4, r5, r6, r7 --- scratch
22 * r8 --- from + PAGE_SIZE
23 * r9 --- not used
24 * r10 --- to
25 * r11 --- from
26 */
27ENTRY(copy_page)
28 mov.l r8,@-r15
29 mov.l r10,@-r15
30 mov.l r11,@-r15
31 mov r4,r10
32 mov r5,r11
33 mov r5,r8
34 mov #(PAGE_SIZE >> 10), r0
35 shll8 r0
36 shll2 r0
37 add r0,r8
38 !
391: mov.l @r11+,r0
40 mov.l @r11+,r1
41 mov.l @r11+,r2
42 mov.l @r11+,r3
43 mov.l @r11+,r4
44 mov.l @r11+,r5
45 mov.l @r11+,r6
46 mov.l @r11+,r7
47#if defined(CONFIG_CPU_SH4)
48 movca.l r0,@r10
49#else
50 mov.l r0,@r10
51#endif
52 add #32,r10
53 mov.l r7,@-r10
54 mov.l r6,@-r10
55 mov.l r5,@-r10
56 mov.l r4,@-r10
57 mov.l r3,@-r10
58 mov.l r2,@-r10
59 mov.l r1,@-r10
60 cmp/eq r11,r8
61 bf/s 1b
62 add #28,r10
63 !
64 mov.l @r15+,r11
65 mov.l @r15+,r10
66 mov.l @r15+,r8
67 rts
68 nop
69
70/*
71 * __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
72 * Return the number of bytes NOT copied
73 */
74#define EX(...) \
75 9999: __VA_ARGS__ ; \
76 .section __ex_table, "a"; \
77 .long 9999b, 6000f ; \
78 .previous
79#define EX_NO_POP(...) \
80 9999: __VA_ARGS__ ; \
81 .section __ex_table, "a"; \
82 .long 9999b, 6005f ; \
83 .previous
84ENTRY(__copy_user)
85 ! Check if small number of bytes
86 mov #11,r0
87 mov r4,r3
88 cmp/gt r0,r6 ! r6 (len) > r0 (11)
89 bf/s .L_cleanup_loop_no_pop
90 add r6,r3 ! last destination address
91
92 ! Calculate bytes needed to align to src
93 mov.l r11,@-r15
94 neg r5,r0
95 mov.l r10,@-r15
96 add #4,r0
97 mov.l r9,@-r15
98 and #3,r0
99 mov.l r8,@-r15
100 tst r0,r0
101 bt 2f
102
1031:
104 ! Copy bytes to long word align src
105EX( mov.b @r5+,r1 )
106 dt r0
107 add #-1,r6
108EX( mov.b r1,@r4 )
109 bf/s 1b
110 add #1,r4
111
112 ! Jump to appropriate routine depending on dest
1132: mov #3,r1
114 mov r6, r2
115 and r4,r1
116 shlr2 r2
117 shll2 r1
118 mova .L_jump_tbl,r0
119 mov.l @(r0,r1),r1
120 jmp @r1
121 nop
122
123 .align 2
124.L_jump_tbl:
125 .long .L_dest00
126 .long .L_dest01
127 .long .L_dest10
128 .long .L_dest11
129
130/*
131 * Come here if there are less than 12 bytes to copy
132 *
133 * Keep the branch target close, so the bf/s callee doesn't overflow
134 * and result in a more expensive branch being inserted. This is the
135 * fast-path for small copies, the jump via the jump table will hit the
136 * default slow-path cleanup. -PFM.
137 */
138.L_cleanup_loop_no_pop:
139 tst r6,r6 ! Check explicitly for zero
140 bt 1f
141
1422:
143EX_NO_POP( mov.b @r5+,r0 )
144 dt r6
145EX_NO_POP( mov.b r0,@r4 )
146 bf/s 2b
147 add #1,r4
148
1491: mov #0,r0 ! normal return
1505000:
151
152# Exception handler:
153.section .fixup, "ax"
1546005:
155 mov.l 8000f,r1
156 mov r3,r0
157 jmp @r1
158 sub r4,r0
159 .align 2
1608000: .long 5000b
161
162.previous
163 rts
164 nop
165
166! Destination = 00
167
168.L_dest00:
169 ! Skip the large copy for small transfers
170 mov #(32+32-4), r0
171 cmp/gt r6, r0 ! r0 (60) > r6 (len)
172 bt 1f
173
174 ! Align dest to a 32 byte boundary
175 neg r4,r0
176 add #0x20, r0
177 and #0x1f, r0
178 tst r0, r0
179 bt 2f
180
181 sub r0, r6
182 shlr2 r0
1833:
184EX( mov.l @r5+,r1 )
185 dt r0
186EX( mov.l r1,@r4 )
187 bf/s 3b
188 add #4,r4
189
1902:
191EX( mov.l @r5+,r0 )
192EX( mov.l @r5+,r1 )
193EX( mov.l @r5+,r2 )
194EX( mov.l @r5+,r7 )
195EX( mov.l @r5+,r8 )
196EX( mov.l @r5+,r9 )
197EX( mov.l @r5+,r10 )
198EX( mov.l @r5+,r11 )
199#ifdef CONFIG_CPU_SH4
200EX( movca.l r0,@r4 )
201#else
202EX( mov.l r0,@r4 )
203#endif
204 add #-32, r6
205EX( mov.l r1,@(4,r4) )
206 mov #32, r0
207EX( mov.l r2,@(8,r4) )
208 cmp/gt r6, r0 ! r0 (32) > r6 (len)
209EX( mov.l r7,@(12,r4) )
210EX( mov.l r8,@(16,r4) )
211EX( mov.l r9,@(20,r4) )
212EX( mov.l r10,@(24,r4) )
213EX( mov.l r11,@(28,r4) )
214 bf/s 2b
215 add #32,r4
216
2171: mov r6, r0
218 shlr2 r0
219 tst r0, r0
220 bt .L_cleanup
2211:
222EX( mov.l @r5+,r1 )
223 dt r0
224EX( mov.l r1,@r4 )
225 bf/s 1b
226 add #4,r4
227
228 bra .L_cleanup
229 nop
230
231! Destination = 10
232
233.L_dest10:
234 mov r2,r7
235 shlr2 r7
236 shlr r7
237 tst r7,r7
238 mov #7,r0
239 bt/s 1f
240 and r0,r2
2412:
242 dt r7
243#ifdef CONFIG_CPU_LITTLE_ENDIAN
244EX( mov.l @r5+,r0 )
245EX( mov.l @r5+,r1 )
246EX( mov.l @r5+,r8 )
247EX( mov.l @r5+,r9 )
248EX( mov.l @r5+,r10 )
249EX( mov.w r0,@r4 )
250 add #2,r4
251 xtrct r1,r0
252 xtrct r8,r1
253 xtrct r9,r8
254 xtrct r10,r9
255
256EX( mov.l r0,@r4 )
257EX( mov.l r1,@(4,r4) )
258EX( mov.l r8,@(8,r4) )
259EX( mov.l r9,@(12,r4) )
260
261EX( mov.l @r5+,r1 )
262EX( mov.l @r5+,r8 )
263EX( mov.l @r5+,r0 )
264 xtrct r1,r10
265 xtrct r8,r1
266 xtrct r0,r8
267 shlr16 r0
268EX( mov.l r10,@(16,r4) )
269EX( mov.l r1,@(20,r4) )
270EX( mov.l r8,@(24,r4) )
271EX( mov.w r0,@(28,r4) )
272 bf/s 2b
273 add #30,r4
274#else
275EX( mov.l @(28,r5),r0 )
276EX( mov.l @(24,r5),r8 )
277EX( mov.l @(20,r5),r9 )
278EX( mov.l @(16,r5),r10 )
279EX( mov.w r0,@(30,r4) )
280 add #-2,r4
281 xtrct r8,r0
282 xtrct r9,r8
283 xtrct r10,r9
284EX( mov.l r0,@(28,r4) )
285EX( mov.l r8,@(24,r4) )
286EX( mov.l r9,@(20,r4) )
287
288EX( mov.l @(12,r5),r0 )
289EX( mov.l @(8,r5),r8 )
290 xtrct r0,r10
291EX( mov.l @(4,r5),r9 )
292 mov.l r10,@(16,r4)
293EX( mov.l @r5,r10 )
294 xtrct r8,r0
295 xtrct r9,r8
296 xtrct r10,r9
297EX( mov.l r0,@(12,r4) )
298EX( mov.l r8,@(8,r4) )
299 swap.w r10,r0
300EX( mov.l r9,@(4,r4) )
301EX( mov.w r0,@(2,r4) )
302
303 add #32,r5
304 bf/s 2b
305 add #34,r4
306#endif
307 tst r2,r2
308 bt .L_cleanup
309
3101: ! Read longword, write two words per iteration
311EX( mov.l @r5+,r0 )
312 dt r2
313#ifdef CONFIG_CPU_LITTLE_ENDIAN
314EX( mov.w r0,@r4 )
315 shlr16 r0
316EX( mov.w r0,@(2,r4) )
317#else
318EX( mov.w r0,@(2,r4) )
319 shlr16 r0
320EX( mov.w r0,@r4 )
321#endif
322 bf/s 1b
323 add #4,r4
324
325 bra .L_cleanup
326 nop
327
328! Destination = 01 or 11
329
330.L_dest01:
331.L_dest11:
332 ! Read longword, write byte, word, byte per iteration
333EX( mov.l @r5+,r0 )
334 dt r2
335#ifdef CONFIG_CPU_LITTLE_ENDIAN
336EX( mov.b r0,@r4 )
337 shlr8 r0
338 add #1,r4
339EX( mov.w r0,@r4 )
340 shlr16 r0
341EX( mov.b r0,@(2,r4) )
342 bf/s .L_dest01
343 add #3,r4
344#else
345EX( mov.b r0,@(3,r4) )
346 shlr8 r0
347 swap.w r0,r7
348EX( mov.b r7,@r4 )
349 add #1,r4
350EX( mov.w r0,@r4 )
351 bf/s .L_dest01
352 add #3,r4
353#endif
354
355! Cleanup last few bytes
356.L_cleanup:
357 mov r6,r0
358 and #3,r0
359 tst r0,r0
360 bt .L_exit
361 mov r0,r6
362
363.L_cleanup_loop:
364EX( mov.b @r5+,r0 )
365 dt r6
366EX( mov.b r0,@r4 )
367 bf/s .L_cleanup_loop
368 add #1,r4
369
370.L_exit:
371 mov #0,r0 ! normal return
372
3735000:
374
375# Exception handler:
376.section .fixup, "ax"
3776000:
378 mov.l 8000f,r1
379 mov r3,r0
380 jmp @r1
381 sub r4,r0
382 .align 2
3838000: .long 5000b
384
385.previous
386 mov.l @r15+,r8
387 mov.l @r15+,r9
388 mov.l @r15+,r10
389 rts
390 mov.l @r15+,r11
391

source code of linux/arch/sh/lib/copy_page.S