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1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Unified implementation of memcpy, memmove and the __copy_user backend.
7 *
8 * Copyright (C) 1998, 99, 2000, 01, 2002 Ralf Baechle (ralf@gnu.org)
9 * Copyright (C) 1999, 2000, 01, 2002 Silicon Graphics, Inc.
10 * Copyright (C) 2002 Broadcom, Inc.
11 * memcpy/copy_user author: Mark Vandevoorde
12 * Copyright (C) 2007 Maciej W. Rozycki
13 *
14 * Mnemonic names for arguments to memcpy/__copy_user
15 */
16
17/*
18 * Hack to resolve longstanding prefetch issue
19 *
20 * Prefetching may be fatal on some systems if we're prefetching beyond the
21 * end of memory on some systems. It's also a seriously bad idea on non
22 * dma-coherent systems.
23 */
24#ifdef CONFIG_DMA_NONCOHERENT
25#undef CONFIG_CPU_HAS_PREFETCH
26#endif
27#ifdef CONFIG_MIPS_MALTA
28#undef CONFIG_CPU_HAS_PREFETCH
29#endif
30
31#include <asm/asm.h>
32#include <asm/asm-offsets.h>
33#include <asm/regdef.h>
34
35#define dst a0
36#define src a1
37#define len a2
38
39/*
40 * Spec
41 *
42 * memcpy copies len bytes from src to dst and sets v0 to dst.
43 * It assumes that
44 * - src and dst don't overlap
45 * - src is readable
46 * - dst is writable
47 * memcpy uses the standard calling convention
48 *
49 * __copy_user copies up to len bytes from src to dst and sets a2 (len) to
50 * the number of uncopied bytes due to an exception caused by a read or write.
51 * __copy_user assumes that src and dst don't overlap, and that the call is
52 * implementing one of the following:
53 * copy_to_user
54 * - src is readable (no exceptions when reading src)
55 * copy_from_user
56 * - dst is writable (no exceptions when writing dst)
57 * __copy_user uses a non-standard calling convention; see
58 * include/asm-mips/uaccess.h
59 *
60 * When an exception happens on a load, the handler must
61 # ensure that all of the destination buffer is overwritten to prevent
62 * leaking information to user mode programs.
63 */
64
65/*
66 * Implementation
67 */
68
69/*
70 * The exception handler for loads requires that:
71 * 1- AT contain the address of the byte just past the end of the source
72 * of the copy,
73 * 2- src_entry <= src < AT, and
74 * 3- (dst - src) == (dst_entry - src_entry),
75 * The _entry suffix denotes values when __copy_user was called.
76 *
77 * (1) is set up up by uaccess.h and maintained by not writing AT in copy_user
78 * (2) is met by incrementing src by the number of bytes copied
79 * (3) is met by not doing loads between a pair of increments of dst and src
80 *
81 * The exception handlers for stores adjust len (if necessary) and return.
82 * These handlers do not need to overwrite any data.
83 *
84 * For __rmemcpy and memmove an exception is always a kernel bug, therefore
85 * they're not protected.
86 */
87
88#define EXC(inst_reg,addr,handler) \
899: inst_reg, addr; \
90 .section __ex_table,"a"; \
91 PTR 9b, handler; \
92 .previous
93
94/*
95 * Only on the 64-bit kernel we can made use of 64-bit registers.
96 */
97#ifdef CONFIG_64BIT
98#define USE_DOUBLE
99#endif
100
101#ifdef USE_DOUBLE
102
103#define LOAD ld
104#define LOADL ldl
105#define LOADR ldr
106#define STOREL sdl
107#define STORER sdr
108#define STORE sd
109#define ADD daddu
110#define SUB dsubu
111#define SRL dsrl
112#define SRA dsra
113#define SLL dsll
114#define SLLV dsllv
115#define SRLV dsrlv
116#define NBYTES 8
117#define LOG_NBYTES 3
118
119/*
120 * As we are sharing code base with the mips32 tree (which use the o32 ABI
121 * register definitions). We need to redefine the register definitions from
122 * the n64 ABI register naming to the o32 ABI register naming.
123 */
124#undef t0
125#undef t1
126#undef t2
127#undef t3
128#define t0 $8
129#define t1 $9
130#define t2 $10
131#define t3 $11
132#define t4 $12
133#define t5 $13
134#define t6 $14
135#define t7 $15
136
137#else
138
139#define LOAD lw
140#define LOADL lwl
141#define LOADR lwr
142#define STOREL swl
143#define STORER swr
144#define STORE sw
145#define ADD addu
146#define SUB subu
147#define SRL srl
148#define SLL sll
149#define SRA sra
150#define SLLV sllv
151#define SRLV srlv
152#define NBYTES 4
153#define LOG_NBYTES 2
154
155#endif /* USE_DOUBLE */
156
157#ifdef CONFIG_CPU_LITTLE_ENDIAN
158#define LDFIRST LOADR
159#define LDREST LOADL
160#define STFIRST STORER
161#define STREST STOREL
162#define SHIFT_DISCARD SLLV
163#else
164#define LDFIRST LOADL
165#define LDREST LOADR
166#define STFIRST STOREL
167#define STREST STORER
168#define SHIFT_DISCARD SRLV
169#endif
170
171#define FIRST(unit) ((unit)*NBYTES)
172#define REST(unit) (FIRST(unit)+NBYTES-1)
173#define UNIT(unit) FIRST(unit)
174
175#define ADDRMASK (NBYTES-1)
176
177 .text
178 .set noreorder
179#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
180 .set noat
181#else
182 .set at=v1
183#endif
184
185/*
186 * A combined memcpy/__copy_user
187 * __copy_user sets len to 0 for success; else to an upper bound of
188 * the number of uncopied bytes.
189 * memcpy sets v0 to dst.
190 */
191 .align 5
192LEAF(memcpy) /* a0=dst a1=src a2=len */
193 move v0, dst /* return value */
194.L__memcpy:
195FEXPORT(__copy_user)
196 /*
197 * Note: dst & src may be unaligned, len may be 0
198 * Temps
199 */
200#define rem t8
201
202 R10KCBARRIER(0(ra))
203 /*
204 * The "issue break"s below are very approximate.
205 * Issue delays for dcache fills will perturb the schedule, as will
206 * load queue full replay traps, etc.
207 *
208 * If len < NBYTES use byte operations.
209 */
210 PREF( 0, 0(src) )
211 PREF( 1, 0(dst) )
212 sltu t2, len, NBYTES
213 and t1, dst, ADDRMASK
214 PREF( 0, 1*32(src) )
215 PREF( 1, 1*32(dst) )
216 bnez t2, .Lcopy_bytes_checklen
217 and t0, src, ADDRMASK
218 PREF( 0, 2*32(src) )
219 PREF( 1, 2*32(dst) )
220 bnez t1, .Ldst_unaligned
221 nop
222 bnez t0, .Lsrc_unaligned_dst_aligned
223 /*
224 * use delay slot for fall-through
225 * src and dst are aligned; need to compute rem
226 */
227.Lboth_aligned:
228 SRL t0, len, LOG_NBYTES+3 # +3 for 8 units/iter
229 beqz t0, .Lcleanup_both_aligned # len < 8*NBYTES
230 and rem, len, (8*NBYTES-1) # rem = len % (8*NBYTES)
231 PREF( 0, 3*32(src) )
232 PREF( 1, 3*32(dst) )
233 .align 4
2341:
235 R10KCBARRIER(0(ra))
236EXC( LOAD t0, UNIT(0)(src), .Ll_exc)
237EXC( LOAD t1, UNIT(1)(src), .Ll_exc_copy)
238EXC( LOAD t2, UNIT(2)(src), .Ll_exc_copy)
239EXC( LOAD t3, UNIT(3)(src), .Ll_exc_copy)
240 SUB len, len, 8*NBYTES
241EXC( LOAD t4, UNIT(4)(src), .Ll_exc_copy)
242EXC( LOAD t7, UNIT(5)(src), .Ll_exc_copy)
243EXC( STORE t0, UNIT(0)(dst), .Ls_exc_p8u)
244EXC( STORE t1, UNIT(1)(dst), .Ls_exc_p7u)
245EXC( LOAD t0, UNIT(6)(src), .Ll_exc_copy)
246EXC( LOAD t1, UNIT(7)(src), .Ll_exc_copy)
247 ADD src, src, 8*NBYTES
248 ADD dst, dst, 8*NBYTES
249EXC( STORE t2, UNIT(-6)(dst), .Ls_exc_p6u)
250EXC( STORE t3, UNIT(-5)(dst), .Ls_exc_p5u)
251EXC( STORE t4, UNIT(-4)(dst), .Ls_exc_p4u)
252EXC( STORE t7, UNIT(-3)(dst), .Ls_exc_p3u)
253EXC( STORE t0, UNIT(-2)(dst), .Ls_exc_p2u)
254EXC( STORE t1, UNIT(-1)(dst), .Ls_exc_p1u)
255 PREF( 0, 8*32(src) )
256 PREF( 1, 8*32(dst) )
257 bne len, rem, 1b
258 nop
259
260 /*
261 * len == rem == the number of bytes left to copy < 8*NBYTES
262 */
263.Lcleanup_both_aligned:
264 beqz len, .Ldone
265 sltu t0, len, 4*NBYTES
266 bnez t0, .Lless_than_4units
267 and rem, len, (NBYTES-1) # rem = len % NBYTES
268 /*
269 * len >= 4*NBYTES
270 */
271EXC( LOAD t0, UNIT(0)(src), .Ll_exc)
272EXC( LOAD t1, UNIT(1)(src), .Ll_exc_copy)
273EXC( LOAD t2, UNIT(2)(src), .Ll_exc_copy)
274EXC( LOAD t3, UNIT(3)(src), .Ll_exc_copy)
275 SUB len, len, 4*NBYTES
276 ADD src, src, 4*NBYTES
277 R10KCBARRIER(0(ra))
278EXC( STORE t0, UNIT(0)(dst), .Ls_exc_p4u)
279EXC( STORE t1, UNIT(1)(dst), .Ls_exc_p3u)
280EXC( STORE t2, UNIT(2)(dst), .Ls_exc_p2u)
281EXC( STORE t3, UNIT(3)(dst), .Ls_exc_p1u)
282 .set reorder /* DADDI_WAR */
283 ADD dst, dst, 4*NBYTES
284 beqz len, .Ldone
285 .set noreorder
286.Lless_than_4units:
287 /*
288 * rem = len % NBYTES
289 */
290 beq rem, len, .Lcopy_bytes
291 nop
2921:
293 R10KCBARRIER(0(ra))
294EXC( LOAD t0, 0(src), .Ll_exc)
295 ADD src, src, NBYTES
296 SUB len, len, NBYTES
297EXC( STORE t0, 0(dst), .Ls_exc_p1u)
298 .set reorder /* DADDI_WAR */
299 ADD dst, dst, NBYTES
300 bne rem, len, 1b
301 .set noreorder
302
303 /*
304 * src and dst are aligned, need to copy rem bytes (rem < NBYTES)
305 * A loop would do only a byte at a time with possible branch
306 * mispredicts. Can't do an explicit LOAD dst,mask,or,STORE
307 * because can't assume read-access to dst. Instead, use
308 * STREST dst, which doesn't require read access to dst.
309 *
310 * This code should perform better than a simple loop on modern,
311 * wide-issue mips processors because the code has fewer branches and
312 * more instruction-level parallelism.
313 */
314#define bits t2
315 beqz len, .Ldone
316 ADD t1, dst, len # t1 is just past last byte of dst
317 li bits, 8*NBYTES
318 SLL rem, len, 3 # rem = number of bits to keep
319EXC( LOAD t0, 0(src), .Ll_exc)
320 SUB bits, bits, rem # bits = number of bits to discard
321 SHIFT_DISCARD t0, t0, bits
322EXC( STREST t0, -1(t1), .Ls_exc)
323 jr ra
324 move len, zero
325.Ldst_unaligned:
326 /*
327 * dst is unaligned
328 * t0 = src & ADDRMASK
329 * t1 = dst & ADDRMASK; T1 > 0
330 * len >= NBYTES
331 *
332 * Copy enough bytes to align dst
333 * Set match = (src and dst have same alignment)
334 */
335#define match rem
336EXC( LDFIRST t3, FIRST(0)(src), .Ll_exc)
337 ADD t2, zero, NBYTES
338EXC( LDREST t3, REST(0)(src), .Ll_exc_copy)
339 SUB t2, t2, t1 # t2 = number of bytes copied
340 xor match, t0, t1
341 R10KCBARRIER(0(ra))
342EXC( STFIRST t3, FIRST(0)(dst), .Ls_exc)
343 beq len, t2, .Ldone
344 SUB len, len, t2
345 ADD dst, dst, t2
346 beqz match, .Lboth_aligned
347 ADD src, src, t2
348
349.Lsrc_unaligned_dst_aligned:
350 SRL t0, len, LOG_NBYTES+2 # +2 for 4 units/iter
351 PREF( 0, 3*32(src) )
352 beqz t0, .Lcleanup_src_unaligned
353 and rem, len, (4*NBYTES-1) # rem = len % 4*NBYTES
354 PREF( 1, 3*32(dst) )
3551:
356/*
357 * Avoid consecutive LD*'s to the same register since some mips
358 * implementations can't issue them in the same cycle.
359 * It's OK to load FIRST(N+1) before REST(N) because the two addresses
360 * are to the same unit (unless src is aligned, but it's not).
361 */
362 R10KCBARRIER(0(ra))
363EXC( LDFIRST t0, FIRST(0)(src), .Ll_exc)
364EXC( LDFIRST t1, FIRST(1)(src), .Ll_exc_copy)
365 SUB len, len, 4*NBYTES
366EXC( LDREST t0, REST(0)(src), .Ll_exc_copy)
367EXC( LDREST t1, REST(1)(src), .Ll_exc_copy)
368EXC( LDFIRST t2, FIRST(2)(src), .Ll_exc_copy)
369EXC( LDFIRST t3, FIRST(3)(src), .Ll_exc_copy)
370EXC( LDREST t2, REST(2)(src), .Ll_exc_copy)
371EXC( LDREST t3, REST(3)(src), .Ll_exc_copy)
372 PREF( 0, 9*32(src) ) # 0 is PREF_LOAD (not streamed)
373 ADD src, src, 4*NBYTES
374#ifdef CONFIG_CPU_SB1
375 nop # improves slotting
376#endif
377EXC( STORE t0, UNIT(0)(dst), .Ls_exc_p4u)
378EXC( STORE t1, UNIT(1)(dst), .Ls_exc_p3u)
379EXC( STORE t2, UNIT(2)(dst), .Ls_exc_p2u)
380EXC( STORE t3, UNIT(3)(dst), .Ls_exc_p1u)
381 PREF( 1, 9*32(dst) ) # 1 is PREF_STORE (not streamed)
382 .set reorder /* DADDI_WAR */
383 ADD dst, dst, 4*NBYTES
384 bne len, rem, 1b
385 .set noreorder
386
387.Lcleanup_src_unaligned:
388 beqz len, .Ldone
389 and rem, len, NBYTES-1 # rem = len % NBYTES
390 beq rem, len, .Lcopy_bytes
391 nop
3921:
393 R10KCBARRIER(0(ra))
394EXC( LDFIRST t0, FIRST(0)(src), .Ll_exc)
395EXC( LDREST t0, REST(0)(src), .Ll_exc_copy)
396 ADD src, src, NBYTES
397 SUB len, len, NBYTES
398EXC( STORE t0, 0(dst), .Ls_exc_p1u)
399 .set reorder /* DADDI_WAR */
400 ADD dst, dst, NBYTES
401 bne len, rem, 1b
402 .set noreorder
403
404.Lcopy_bytes_checklen:
405 beqz len, .Ldone
406 nop
407.Lcopy_bytes:
408 /* 0 < len < NBYTES */
409 R10KCBARRIER(0(ra))
410#define COPY_BYTE(N) \
411EXC( lb t0, N(src), .Ll_exc); \
412 SUB len, len, 1; \
413 beqz len, .Ldone; \
414EXC( sb t0, N(dst), .Ls_exc_p1)
415
416 COPY_BYTE(0)
417 COPY_BYTE(1)
418#ifdef USE_DOUBLE
419 COPY_BYTE(2)
420 COPY_BYTE(3)
421 COPY_BYTE(4)
422 COPY_BYTE(5)
423#endif
424EXC( lb t0, NBYTES-2(src), .Ll_exc)
425 SUB len, len, 1
426 jr ra
427EXC( sb t0, NBYTES-2(dst), .Ls_exc_p1)
428.Ldone:
429 jr ra
430 nop
431 END(memcpy)
432
433.Ll_exc_copy:
434 /*
435 * Copy bytes from src until faulting load address (or until a
436 * lb faults)
437 *
438 * When reached by a faulting LDFIRST/LDREST, THREAD_BUADDR($28)
439 * may be more than a byte beyond the last address.
440 * Hence, the lb below may get an exception.
441 *
442 * Assumes src < THREAD_BUADDR($28)
443 */
444 LOAD t0, TI_TASK($28)
445 nop
446 LOAD t0, THREAD_BUADDR(t0)
4471:
448EXC( lb t1, 0(src), .Ll_exc)
449 ADD src, src, 1
450 sb t1, 0(dst) # can't fault -- we're copy_from_user
451 .set reorder /* DADDI_WAR */
452 ADD dst, dst, 1
453 bne src, t0, 1b
454 .set noreorder
455.Ll_exc:
456 LOAD t0, TI_TASK($28)
457 nop
458 LOAD t0, THREAD_BUADDR(t0) # t0 is just past last good address
459 nop
460 SUB len, AT, t0 # len number of uncopied bytes
461 /*
462 * Here's where we rely on src and dst being incremented in tandem,
463 * See (3) above.
464 * dst += (fault addr - src) to put dst at first byte to clear
465 */
466 ADD dst, t0 # compute start address in a1
467 SUB dst, src
468 /*
469 * Clear len bytes starting at dst. Can't call __bzero because it
470 * might modify len. An inefficient loop for these rare times...
471 */
472 .set reorder /* DADDI_WAR */
473 SUB src, len, 1
474 beqz len, .Ldone
475 .set noreorder
4761: sb zero, 0(dst)
477 ADD dst, dst, 1
478#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
479 bnez src, 1b
480 SUB src, src, 1
481#else
482 .set push
483 .set noat
484 li v1, 1
485 bnez src, 1b
486 SUB src, src, v1
487 .set pop
488#endif
489 jr ra
490 nop
491
492
493#define SEXC(n) \
494 .set reorder; /* DADDI_WAR */ \
495.Ls_exc_p ## n ## u: \
496 ADD len, len, n*NBYTES; \
497 jr ra; \
498 .set noreorder
499
500SEXC(8)
501SEXC(7)
502SEXC(6)
503SEXC(5)
504SEXC(4)
505SEXC(3)
506SEXC(2)
507SEXC(1)
508
509.Ls_exc_p1:
510 .set reorder /* DADDI_WAR */
511 ADD len, len, 1
512 jr ra
513 .set noreorder
514.Ls_exc:
515 jr ra
516 nop
517
518 .align 5
519LEAF(memmove)
520 ADD t0, a0, a2
521 ADD t1, a1, a2
522 sltu t0, a1, t0 # dst + len <= src -> memcpy
523 sltu t1, a0, t1 # dst >= src + len -> memcpy
524 and t0, t1
525 beqz t0, .L__memcpy
526 move v0, a0 /* return value */
527 beqz a2, .Lr_out
528 END(memmove)
529
530 /* fall through to __rmemcpy */
531LEAF(__rmemcpy) /* a0=dst a1=src a2=len */
532 sltu t0, a1, a0
533 beqz t0, .Lr_end_bytes_up # src >= dst
534 nop
535 ADD a0, a2 # dst = dst + len
536 ADD a1, a2 # src = src + len
537
538.Lr_end_bytes:
539 R10KCBARRIER(0(ra))
540 lb t0, -1(a1)
541 SUB a2, a2, 0x1
542 sb t0, -1(a0)
543 SUB a1, a1, 0x1
544 .set reorder /* DADDI_WAR */
545 SUB a0, a0, 0x1
546 bnez a2, .Lr_end_bytes
547 .set noreorder
548
549.Lr_out:
550 jr ra
551 move a2, zero
552
553.Lr_end_bytes_up:
554 R10KCBARRIER(0(ra))
555 lb t0, (a1)
556 SUB a2, a2, 0x1
557 sb t0, (a0)
558 ADD a1, a1, 0x1
559 .set reorder /* DADDI_WAR */
560 ADD a0, a0, 0x1
561 bnez a2, .Lr_end_bytes_up
562 .set noreorder
563
564 jr ra
565 move a2, zero
566 END(__rmemcpy)
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Unified implementation of memcpy, memmove and the __copy_user backend.
7 *
8 * Copyright (C) 1998, 99, 2000, 01, 2002 Ralf Baechle (ralf@gnu.org)
9 * Copyright (C) 1999, 2000, 01, 2002 Silicon Graphics, Inc.
10 * Copyright (C) 2002 Broadcom, Inc.
11 * memcpy/copy_user author: Mark Vandevoorde
12 * Copyright (C) 2007 Maciej W. Rozycki
13 * Copyright (C) 2014 Imagination Technologies Ltd.
14 *
15 * Mnemonic names for arguments to memcpy/__copy_user
16 */
17
18/*
19 * Hack to resolve longstanding prefetch issue
20 *
21 * Prefetching may be fatal on some systems if we're prefetching beyond the
22 * end of memory on some systems. It's also a seriously bad idea on non
23 * dma-coherent systems.
24 */
25#ifdef CONFIG_DMA_NONCOHERENT
26#undef CONFIG_CPU_HAS_PREFETCH
27#endif
28#ifdef CONFIG_MIPS_MALTA
29#undef CONFIG_CPU_HAS_PREFETCH
30#endif
31
32#include <asm/asm.h>
33#include <asm/asm-offsets.h>
34#include <asm/regdef.h>
35
36#define dst a0
37#define src a1
38#define len a2
39
40/*
41 * Spec
42 *
43 * memcpy copies len bytes from src to dst and sets v0 to dst.
44 * It assumes that
45 * - src and dst don't overlap
46 * - src is readable
47 * - dst is writable
48 * memcpy uses the standard calling convention
49 *
50 * __copy_user copies up to len bytes from src to dst and sets a2 (len) to
51 * the number of uncopied bytes due to an exception caused by a read or write.
52 * __copy_user assumes that src and dst don't overlap, and that the call is
53 * implementing one of the following:
54 * copy_to_user
55 * - src is readable (no exceptions when reading src)
56 * copy_from_user
57 * - dst is writable (no exceptions when writing dst)
58 * __copy_user uses a non-standard calling convention; see
59 * include/asm-mips/uaccess.h
60 *
61 * When an exception happens on a load, the handler must
62 # ensure that all of the destination buffer is overwritten to prevent
63 * leaking information to user mode programs.
64 */
65
66/*
67 * Implementation
68 */
69
70/*
71 * The exception handler for loads requires that:
72 * 1- AT contain the address of the byte just past the end of the source
73 * of the copy,
74 * 2- src_entry <= src < AT, and
75 * 3- (dst - src) == (dst_entry - src_entry),
76 * The _entry suffix denotes values when __copy_user was called.
77 *
78 * (1) is set up up by uaccess.h and maintained by not writing AT in copy_user
79 * (2) is met by incrementing src by the number of bytes copied
80 * (3) is met by not doing loads between a pair of increments of dst and src
81 *
82 * The exception handlers for stores adjust len (if necessary) and return.
83 * These handlers do not need to overwrite any data.
84 *
85 * For __rmemcpy and memmove an exception is always a kernel bug, therefore
86 * they're not protected.
87 */
88
89/* Instruction type */
90#define LD_INSN 1
91#define ST_INSN 2
92/* Pretech type */
93#define SRC_PREFETCH 1
94#define DST_PREFETCH 2
95#define LEGACY_MODE 1
96#define EVA_MODE 2
97#define USEROP 1
98#define KERNELOP 2
99
100/*
101 * Wrapper to add an entry in the exception table
102 * in case the insn causes a memory exception.
103 * Arguments:
104 * insn : Load/store instruction
105 * type : Instruction type
106 * reg : Register
107 * addr : Address
108 * handler : Exception handler
109 */
110
111#define EXC(insn, type, reg, addr, handler) \
112 .if \mode == LEGACY_MODE; \
1139: insn reg, addr; \
114 .section __ex_table,"a"; \
115 PTR 9b, handler; \
116 .previous; \
117 /* This is assembled in EVA mode */ \
118 .else; \
119 /* If loading from user or storing to user */ \
120 .if ((\from == USEROP) && (type == LD_INSN)) || \
121 ((\to == USEROP) && (type == ST_INSN)); \
1229: __BUILD_EVA_INSN(insn##e, reg, addr); \
123 .section __ex_table,"a"; \
124 PTR 9b, handler; \
125 .previous; \
126 .else; \
127 /* \
128 * Still in EVA, but no need for \
129 * exception handler or EVA insn \
130 */ \
131 insn reg, addr; \
132 .endif; \
133 .endif
134
135/*
136 * Only on the 64-bit kernel we can made use of 64-bit registers.
137 */
138#ifdef CONFIG_64BIT
139#define USE_DOUBLE
140#endif
141
142#ifdef USE_DOUBLE
143
144#define LOADK ld /* No exception */
145#define LOAD(reg, addr, handler) EXC(ld, LD_INSN, reg, addr, handler)
146#define LOADL(reg, addr, handler) EXC(ldl, LD_INSN, reg, addr, handler)
147#define LOADR(reg, addr, handler) EXC(ldr, LD_INSN, reg, addr, handler)
148#define STOREL(reg, addr, handler) EXC(sdl, ST_INSN, reg, addr, handler)
149#define STORER(reg, addr, handler) EXC(sdr, ST_INSN, reg, addr, handler)
150#define STORE(reg, addr, handler) EXC(sd, ST_INSN, reg, addr, handler)
151#define ADD daddu
152#define SUB dsubu
153#define SRL dsrl
154#define SRA dsra
155#define SLL dsll
156#define SLLV dsllv
157#define SRLV dsrlv
158#define NBYTES 8
159#define LOG_NBYTES 3
160
161/*
162 * As we are sharing code base with the mips32 tree (which use the o32 ABI
163 * register definitions). We need to redefine the register definitions from
164 * the n64 ABI register naming to the o32 ABI register naming.
165 */
166#undef t0
167#undef t1
168#undef t2
169#undef t3
170#define t0 $8
171#define t1 $9
172#define t2 $10
173#define t3 $11
174#define t4 $12
175#define t5 $13
176#define t6 $14
177#define t7 $15
178
179#else
180
181#define LOADK lw /* No exception */
182#define LOAD(reg, addr, handler) EXC(lw, LD_INSN, reg, addr, handler)
183#define LOADL(reg, addr, handler) EXC(lwl, LD_INSN, reg, addr, handler)
184#define LOADR(reg, addr, handler) EXC(lwr, LD_INSN, reg, addr, handler)
185#define STOREL(reg, addr, handler) EXC(swl, ST_INSN, reg, addr, handler)
186#define STORER(reg, addr, handler) EXC(swr, ST_INSN, reg, addr, handler)
187#define STORE(reg, addr, handler) EXC(sw, ST_INSN, reg, addr, handler)
188#define ADD addu
189#define SUB subu
190#define SRL srl
191#define SLL sll
192#define SRA sra
193#define SLLV sllv
194#define SRLV srlv
195#define NBYTES 4
196#define LOG_NBYTES 2
197
198#endif /* USE_DOUBLE */
199
200#define LOADB(reg, addr, handler) EXC(lb, LD_INSN, reg, addr, handler)
201#define STOREB(reg, addr, handler) EXC(sb, ST_INSN, reg, addr, handler)
202
203#define _PREF(hint, addr, type) \
204 .if \mode == LEGACY_MODE; \
205 PREF(hint, addr); \
206 .else; \
207 .if ((\from == USEROP) && (type == SRC_PREFETCH)) || \
208 ((\to == USEROP) && (type == DST_PREFETCH)); \
209 /* \
210 * PREFE has only 9 bits for the offset \
211 * compared to PREF which has 16, so it may \
212 * need to use the $at register but this \
213 * register should remain intact because it's \
214 * used later on. Therefore use $v1. \
215 */ \
216 .set at=v1; \
217 PREFE(hint, addr); \
218 .set noat; \
219 .else; \
220 PREF(hint, addr); \
221 .endif; \
222 .endif
223
224#define PREFS(hint, addr) _PREF(hint, addr, SRC_PREFETCH)
225#define PREFD(hint, addr) _PREF(hint, addr, DST_PREFETCH)
226
227#ifdef CONFIG_CPU_LITTLE_ENDIAN
228#define LDFIRST LOADR
229#define LDREST LOADL
230#define STFIRST STORER
231#define STREST STOREL
232#define SHIFT_DISCARD SLLV
233#else
234#define LDFIRST LOADL
235#define LDREST LOADR
236#define STFIRST STOREL
237#define STREST STORER
238#define SHIFT_DISCARD SRLV
239#endif
240
241#define FIRST(unit) ((unit)*NBYTES)
242#define REST(unit) (FIRST(unit)+NBYTES-1)
243#define UNIT(unit) FIRST(unit)
244
245#define ADDRMASK (NBYTES-1)
246
247 .text
248 .set noreorder
249#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
250 .set noat
251#else
252 .set at=v1
253#endif
254
255 .align 5
256
257 /*
258 * Macro to build the __copy_user common code
259 * Arguements:
260 * mode : LEGACY_MODE or EVA_MODE
261 * from : Source operand. USEROP or KERNELOP
262 * to : Destination operand. USEROP or KERNELOP
263 */
264 .macro __BUILD_COPY_USER mode, from, to
265
266 /* initialize __memcpy if this the first time we execute this macro */
267 .ifnotdef __memcpy
268 .set __memcpy, 1
269 .hidden __memcpy /* make sure it does not leak */
270 .endif
271
272 /*
273 * Note: dst & src may be unaligned, len may be 0
274 * Temps
275 */
276#define rem t8
277
278 R10KCBARRIER(0(ra))
279 /*
280 * The "issue break"s below are very approximate.
281 * Issue delays for dcache fills will perturb the schedule, as will
282 * load queue full replay traps, etc.
283 *
284 * If len < NBYTES use byte operations.
285 */
286 PREFS( 0, 0(src) )
287 PREFD( 1, 0(dst) )
288 sltu t2, len, NBYTES
289 and t1, dst, ADDRMASK
290 PREFS( 0, 1*32(src) )
291 PREFD( 1, 1*32(dst) )
292 bnez t2, .Lcopy_bytes_checklen\@
293 and t0, src, ADDRMASK
294 PREFS( 0, 2*32(src) )
295 PREFD( 1, 2*32(dst) )
296 bnez t1, .Ldst_unaligned\@
297 nop
298 bnez t0, .Lsrc_unaligned_dst_aligned\@
299 /*
300 * use delay slot for fall-through
301 * src and dst are aligned; need to compute rem
302 */
303.Lboth_aligned\@:
304 SRL t0, len, LOG_NBYTES+3 # +3 for 8 units/iter
305 beqz t0, .Lcleanup_both_aligned\@ # len < 8*NBYTES
306 and rem, len, (8*NBYTES-1) # rem = len % (8*NBYTES)
307 PREFS( 0, 3*32(src) )
308 PREFD( 1, 3*32(dst) )
309 .align 4
3101:
311 R10KCBARRIER(0(ra))
312 LOAD(t0, UNIT(0)(src), .Ll_exc\@)
313 LOAD(t1, UNIT(1)(src), .Ll_exc_copy\@)
314 LOAD(t2, UNIT(2)(src), .Ll_exc_copy\@)
315 LOAD(t3, UNIT(3)(src), .Ll_exc_copy\@)
316 SUB len, len, 8*NBYTES
317 LOAD(t4, UNIT(4)(src), .Ll_exc_copy\@)
318 LOAD(t7, UNIT(5)(src), .Ll_exc_copy\@)
319 STORE(t0, UNIT(0)(dst), .Ls_exc_p8u\@)
320 STORE(t1, UNIT(1)(dst), .Ls_exc_p7u\@)
321 LOAD(t0, UNIT(6)(src), .Ll_exc_copy\@)
322 LOAD(t1, UNIT(7)(src), .Ll_exc_copy\@)
323 ADD src, src, 8*NBYTES
324 ADD dst, dst, 8*NBYTES
325 STORE(t2, UNIT(-6)(dst), .Ls_exc_p6u\@)
326 STORE(t3, UNIT(-5)(dst), .Ls_exc_p5u\@)
327 STORE(t4, UNIT(-4)(dst), .Ls_exc_p4u\@)
328 STORE(t7, UNIT(-3)(dst), .Ls_exc_p3u\@)
329 STORE(t0, UNIT(-2)(dst), .Ls_exc_p2u\@)
330 STORE(t1, UNIT(-1)(dst), .Ls_exc_p1u\@)
331 PREFS( 0, 8*32(src) )
332 PREFD( 1, 8*32(dst) )
333 bne len, rem, 1b
334 nop
335
336 /*
337 * len == rem == the number of bytes left to copy < 8*NBYTES
338 */
339.Lcleanup_both_aligned\@:
340 beqz len, .Ldone\@
341 sltu t0, len, 4*NBYTES
342 bnez t0, .Lless_than_4units\@
343 and rem, len, (NBYTES-1) # rem = len % NBYTES
344 /*
345 * len >= 4*NBYTES
346 */
347 LOAD( t0, UNIT(0)(src), .Ll_exc\@)
348 LOAD( t1, UNIT(1)(src), .Ll_exc_copy\@)
349 LOAD( t2, UNIT(2)(src), .Ll_exc_copy\@)
350 LOAD( t3, UNIT(3)(src), .Ll_exc_copy\@)
351 SUB len, len, 4*NBYTES
352 ADD src, src, 4*NBYTES
353 R10KCBARRIER(0(ra))
354 STORE(t0, UNIT(0)(dst), .Ls_exc_p4u\@)
355 STORE(t1, UNIT(1)(dst), .Ls_exc_p3u\@)
356 STORE(t2, UNIT(2)(dst), .Ls_exc_p2u\@)
357 STORE(t3, UNIT(3)(dst), .Ls_exc_p1u\@)
358 .set reorder /* DADDI_WAR */
359 ADD dst, dst, 4*NBYTES
360 beqz len, .Ldone\@
361 .set noreorder
362.Lless_than_4units\@:
363 /*
364 * rem = len % NBYTES
365 */
366 beq rem, len, .Lcopy_bytes\@
367 nop
3681:
369 R10KCBARRIER(0(ra))
370 LOAD(t0, 0(src), .Ll_exc\@)
371 ADD src, src, NBYTES
372 SUB len, len, NBYTES
373 STORE(t0, 0(dst), .Ls_exc_p1u\@)
374 .set reorder /* DADDI_WAR */
375 ADD dst, dst, NBYTES
376 bne rem, len, 1b
377 .set noreorder
378
379 /*
380 * src and dst are aligned, need to copy rem bytes (rem < NBYTES)
381 * A loop would do only a byte at a time with possible branch
382 * mispredicts. Can't do an explicit LOAD dst,mask,or,STORE
383 * because can't assume read-access to dst. Instead, use
384 * STREST dst, which doesn't require read access to dst.
385 *
386 * This code should perform better than a simple loop on modern,
387 * wide-issue mips processors because the code has fewer branches and
388 * more instruction-level parallelism.
389 */
390#define bits t2
391 beqz len, .Ldone\@
392 ADD t1, dst, len # t1 is just past last byte of dst
393 li bits, 8*NBYTES
394 SLL rem, len, 3 # rem = number of bits to keep
395 LOAD(t0, 0(src), .Ll_exc\@)
396 SUB bits, bits, rem # bits = number of bits to discard
397 SHIFT_DISCARD t0, t0, bits
398 STREST(t0, -1(t1), .Ls_exc\@)
399 jr ra
400 move len, zero
401.Ldst_unaligned\@:
402 /*
403 * dst is unaligned
404 * t0 = src & ADDRMASK
405 * t1 = dst & ADDRMASK; T1 > 0
406 * len >= NBYTES
407 *
408 * Copy enough bytes to align dst
409 * Set match = (src and dst have same alignment)
410 */
411#define match rem
412 LDFIRST(t3, FIRST(0)(src), .Ll_exc\@)
413 ADD t2, zero, NBYTES
414 LDREST(t3, REST(0)(src), .Ll_exc_copy\@)
415 SUB t2, t2, t1 # t2 = number of bytes copied
416 xor match, t0, t1
417 R10KCBARRIER(0(ra))
418 STFIRST(t3, FIRST(0)(dst), .Ls_exc\@)
419 beq len, t2, .Ldone\@
420 SUB len, len, t2
421 ADD dst, dst, t2
422 beqz match, .Lboth_aligned\@
423 ADD src, src, t2
424
425.Lsrc_unaligned_dst_aligned\@:
426 SRL t0, len, LOG_NBYTES+2 # +2 for 4 units/iter
427 PREFS( 0, 3*32(src) )
428 beqz t0, .Lcleanup_src_unaligned\@
429 and rem, len, (4*NBYTES-1) # rem = len % 4*NBYTES
430 PREFD( 1, 3*32(dst) )
4311:
432/*
433 * Avoid consecutive LD*'s to the same register since some mips
434 * implementations can't issue them in the same cycle.
435 * It's OK to load FIRST(N+1) before REST(N) because the two addresses
436 * are to the same unit (unless src is aligned, but it's not).
437 */
438 R10KCBARRIER(0(ra))
439 LDFIRST(t0, FIRST(0)(src), .Ll_exc\@)
440 LDFIRST(t1, FIRST(1)(src), .Ll_exc_copy\@)
441 SUB len, len, 4*NBYTES
442 LDREST(t0, REST(0)(src), .Ll_exc_copy\@)
443 LDREST(t1, REST(1)(src), .Ll_exc_copy\@)
444 LDFIRST(t2, FIRST(2)(src), .Ll_exc_copy\@)
445 LDFIRST(t3, FIRST(3)(src), .Ll_exc_copy\@)
446 LDREST(t2, REST(2)(src), .Ll_exc_copy\@)
447 LDREST(t3, REST(3)(src), .Ll_exc_copy\@)
448 PREFS( 0, 9*32(src) ) # 0 is PREF_LOAD (not streamed)
449 ADD src, src, 4*NBYTES
450#ifdef CONFIG_CPU_SB1
451 nop # improves slotting
452#endif
453 STORE(t0, UNIT(0)(dst), .Ls_exc_p4u\@)
454 STORE(t1, UNIT(1)(dst), .Ls_exc_p3u\@)
455 STORE(t2, UNIT(2)(dst), .Ls_exc_p2u\@)
456 STORE(t3, UNIT(3)(dst), .Ls_exc_p1u\@)
457 PREFD( 1, 9*32(dst) ) # 1 is PREF_STORE (not streamed)
458 .set reorder /* DADDI_WAR */
459 ADD dst, dst, 4*NBYTES
460 bne len, rem, 1b
461 .set noreorder
462
463.Lcleanup_src_unaligned\@:
464 beqz len, .Ldone\@
465 and rem, len, NBYTES-1 # rem = len % NBYTES
466 beq rem, len, .Lcopy_bytes\@
467 nop
4681:
469 R10KCBARRIER(0(ra))
470 LDFIRST(t0, FIRST(0)(src), .Ll_exc\@)
471 LDREST(t0, REST(0)(src), .Ll_exc_copy\@)
472 ADD src, src, NBYTES
473 SUB len, len, NBYTES
474 STORE(t0, 0(dst), .Ls_exc_p1u\@)
475 .set reorder /* DADDI_WAR */
476 ADD dst, dst, NBYTES
477 bne len, rem, 1b
478 .set noreorder
479
480.Lcopy_bytes_checklen\@:
481 beqz len, .Ldone\@
482 nop
483.Lcopy_bytes\@:
484 /* 0 < len < NBYTES */
485 R10KCBARRIER(0(ra))
486#define COPY_BYTE(N) \
487 LOADB(t0, N(src), .Ll_exc\@); \
488 SUB len, len, 1; \
489 beqz len, .Ldone\@; \
490 STOREB(t0, N(dst), .Ls_exc_p1\@)
491
492 COPY_BYTE(0)
493 COPY_BYTE(1)
494#ifdef USE_DOUBLE
495 COPY_BYTE(2)
496 COPY_BYTE(3)
497 COPY_BYTE(4)
498 COPY_BYTE(5)
499#endif
500 LOADB(t0, NBYTES-2(src), .Ll_exc\@)
501 SUB len, len, 1
502 jr ra
503 STOREB(t0, NBYTES-2(dst), .Ls_exc_p1\@)
504.Ldone\@:
505 jr ra
506 .if __memcpy == 1
507 END(memcpy)
508 .set __memcpy, 0
509 .hidden __memcpy
510 .endif
511
512.Ll_exc_copy\@:
513 /*
514 * Copy bytes from src until faulting load address (or until a
515 * lb faults)
516 *
517 * When reached by a faulting LDFIRST/LDREST, THREAD_BUADDR($28)
518 * may be more than a byte beyond the last address.
519 * Hence, the lb below may get an exception.
520 *
521 * Assumes src < THREAD_BUADDR($28)
522 */
523 LOADK t0, TI_TASK($28)
524 nop
525 LOADK t0, THREAD_BUADDR(t0)
5261:
527 LOADB(t1, 0(src), .Ll_exc\@)
528 ADD src, src, 1
529 sb t1, 0(dst) # can't fault -- we're copy_from_user
530 .set reorder /* DADDI_WAR */
531 ADD dst, dst, 1
532 bne src, t0, 1b
533 .set noreorder
534.Ll_exc\@:
535 LOADK t0, TI_TASK($28)
536 nop
537 LOADK t0, THREAD_BUADDR(t0) # t0 is just past last good address
538 nop
539 SUB len, AT, t0 # len number of uncopied bytes
540 bnez t6, .Ldone\@ /* Skip the zeroing part if inatomic */
541 /*
542 * Here's where we rely on src and dst being incremented in tandem,
543 * See (3) above.
544 * dst += (fault addr - src) to put dst at first byte to clear
545 */
546 ADD dst, t0 # compute start address in a1
547 SUB dst, src
548 /*
549 * Clear len bytes starting at dst. Can't call __bzero because it
550 * might modify len. An inefficient loop for these rare times...
551 */
552 .set reorder /* DADDI_WAR */
553 SUB src, len, 1
554 beqz len, .Ldone\@
555 .set noreorder
5561: sb zero, 0(dst)
557 ADD dst, dst, 1
558#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
559 bnez src, 1b
560 SUB src, src, 1
561#else
562 .set push
563 .set noat
564 li v1, 1
565 bnez src, 1b
566 SUB src, src, v1
567 .set pop
568#endif
569 jr ra
570 nop
571
572
573#define SEXC(n) \
574 .set reorder; /* DADDI_WAR */ \
575.Ls_exc_p ## n ## u\@: \
576 ADD len, len, n*NBYTES; \
577 jr ra; \
578 .set noreorder
579
580SEXC(8)
581SEXC(7)
582SEXC(6)
583SEXC(5)
584SEXC(4)
585SEXC(3)
586SEXC(2)
587SEXC(1)
588
589.Ls_exc_p1\@:
590 .set reorder /* DADDI_WAR */
591 ADD len, len, 1
592 jr ra
593 .set noreorder
594.Ls_exc\@:
595 jr ra
596 nop
597 .endm
598
599 .align 5
600LEAF(memmove)
601 ADD t0, a0, a2
602 ADD t1, a1, a2
603 sltu t0, a1, t0 # dst + len <= src -> memcpy
604 sltu t1, a0, t1 # dst >= src + len -> memcpy
605 and t0, t1
606 beqz t0, .L__memcpy
607 move v0, a0 /* return value */
608 beqz a2, .Lr_out
609 END(memmove)
610
611 /* fall through to __rmemcpy */
612LEAF(__rmemcpy) /* a0=dst a1=src a2=len */
613 sltu t0, a1, a0
614 beqz t0, .Lr_end_bytes_up # src >= dst
615 nop
616 ADD a0, a2 # dst = dst + len
617 ADD a1, a2 # src = src + len
618
619.Lr_end_bytes:
620 R10KCBARRIER(0(ra))
621 lb t0, -1(a1)
622 SUB a2, a2, 0x1
623 sb t0, -1(a0)
624 SUB a1, a1, 0x1
625 .set reorder /* DADDI_WAR */
626 SUB a0, a0, 0x1
627 bnez a2, .Lr_end_bytes
628 .set noreorder
629
630.Lr_out:
631 jr ra
632 move a2, zero
633
634.Lr_end_bytes_up:
635 R10KCBARRIER(0(ra))
636 lb t0, (a1)
637 SUB a2, a2, 0x1
638 sb t0, (a0)
639 ADD a1, a1, 0x1
640 .set reorder /* DADDI_WAR */
641 ADD a0, a0, 0x1
642 bnez a2, .Lr_end_bytes_up
643 .set noreorder
644
645 jr ra
646 move a2, zero
647 END(__rmemcpy)
648
649/*
650 * t6 is used as a flag to note inatomic mode.
651 */
652LEAF(__copy_user_inatomic)
653 b __copy_user_common
654 li t6, 1
655 END(__copy_user_inatomic)
656
657/*
658 * A combined memcpy/__copy_user
659 * __copy_user sets len to 0 for success; else to an upper bound of
660 * the number of uncopied bytes.
661 * memcpy sets v0 to dst.
662 */
663 .align 5
664LEAF(memcpy) /* a0=dst a1=src a2=len */
665 move v0, dst /* return value */
666.L__memcpy:
667FEXPORT(__copy_user)
668 li t6, 0 /* not inatomic */
669__copy_user_common:
670 /* Legacy Mode, user <-> user */
671 __BUILD_COPY_USER LEGACY_MODE USEROP USEROP
672
673#ifdef CONFIG_EVA
674
675/*
676 * For EVA we need distinct symbols for reading and writing to user space.
677 * This is because we need to use specific EVA instructions to perform the
678 * virtual <-> physical translation when a virtual address is actually in user
679 * space
680 */
681
682LEAF(__copy_user_inatomic_eva)
683 b __copy_from_user_common
684 li t6, 1
685 END(__copy_user_inatomic_eva)
686
687/*
688 * __copy_from_user (EVA)
689 */
690
691LEAF(__copy_from_user_eva)
692 li t6, 0 /* not inatomic */
693__copy_from_user_common:
694 __BUILD_COPY_USER EVA_MODE USEROP KERNELOP
695END(__copy_from_user_eva)
696
697
698
699/*
700 * __copy_to_user (EVA)
701 */
702
703LEAF(__copy_to_user_eva)
704__BUILD_COPY_USER EVA_MODE KERNELOP USEROP
705END(__copy_to_user_eva)
706
707/*
708 * __copy_in_user (EVA)
709 */
710
711LEAF(__copy_in_user_eva)
712__BUILD_COPY_USER EVA_MODE USEROP USEROP
713END(__copy_in_user_eva)
714
715#endif