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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Itanium 2-optimized version of memcpy and copy_user function
4 *
5 * Inputs:
6 * in0: destination address
7 * in1: source address
8 * in2: number of bytes to copy
9 * Output:
10 * for memcpy: return dest
11 * for copy_user: return 0 if success,
12 * or number of byte NOT copied if error occurred.
13 *
14 * Copyright (C) 2002 Intel Corp.
15 * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com>
16 */
17#include <asm/asmmacro.h>
18#include <asm/page.h>
19#include <asm/export.h>
20
21#define EK(y...) EX(y)
22
23/* McKinley specific optimization */
24
25#define retval r8
26#define saved_pfs r31
27#define saved_lc r10
28#define saved_pr r11
29#define saved_in0 r14
30#define saved_in1 r15
31#define saved_in2 r16
32
33#define src0 r2
34#define src1 r3
35#define dst0 r17
36#define dst1 r18
37#define cnt r9
38
39/* r19-r30 are temp for each code section */
40#define PREFETCH_DIST 8
41#define src_pre_mem r19
42#define dst_pre_mem r20
43#define src_pre_l2 r21
44#define dst_pre_l2 r22
45#define t1 r23
46#define t2 r24
47#define t3 r25
48#define t4 r26
49#define t5 t1 // alias!
50#define t6 t2 // alias!
51#define t7 t3 // alias!
52#define n8 r27
53#define t9 t5 // alias!
54#define t10 t4 // alias!
55#define t11 t7 // alias!
56#define t12 t6 // alias!
57#define t14 t10 // alias!
58#define t13 r28
59#define t15 r29
60#define tmp r30
61
62/* defines for long_copy block */
63#define A 0
64#define B (PREFETCH_DIST)
65#define C (B + PREFETCH_DIST)
66#define D (C + 1)
67#define N (D + 1)
68#define Nrot ((N + 7) & ~7)
69
70/* alias */
71#define in0 r32
72#define in1 r33
73#define in2 r34
74
75GLOBAL_ENTRY(memcpy)
76 and r28=0x7,in0
77 and r29=0x7,in1
78 mov f6=f0
79 mov retval=in0
80 br.cond.sptk .common_code
81 ;;
82END(memcpy)
83EXPORT_SYMBOL(memcpy)
84GLOBAL_ENTRY(__copy_user)
85 .prologue
86// check dest alignment
87 and r28=0x7,in0
88 and r29=0x7,in1
89 mov f6=f1
90 mov saved_in0=in0 // save dest pointer
91 mov saved_in1=in1 // save src pointer
92 mov retval=r0 // initialize return value
93 ;;
94.common_code:
95 cmp.gt p15,p0=8,in2 // check for small size
96 cmp.ne p13,p0=0,r28 // check dest alignment
97 cmp.ne p14,p0=0,r29 // check src alignment
98 add src0=0,in1
99 sub r30=8,r28 // for .align_dest
100 mov saved_in2=in2 // save len
101 ;;
102 add dst0=0,in0
103 add dst1=1,in0 // dest odd index
104 cmp.le p6,p0 = 1,r30 // for .align_dest
105(p15) br.cond.dpnt .memcpy_short
106(p13) br.cond.dpnt .align_dest
107(p14) br.cond.dpnt .unaligned_src
108 ;;
109
110// both dest and src are aligned on 8-byte boundary
111.aligned_src:
112 .save ar.pfs, saved_pfs
113 alloc saved_pfs=ar.pfs,3,Nrot-3,0,Nrot
114 .save pr, saved_pr
115 mov saved_pr=pr
116
117 shr.u cnt=in2,7 // this much cache line
118 ;;
119 cmp.lt p6,p0=2*PREFETCH_DIST,cnt
120 cmp.lt p7,p8=1,cnt
121 .save ar.lc, saved_lc
122 mov saved_lc=ar.lc
123 .body
124 add cnt=-1,cnt
125 add src_pre_mem=0,in1 // prefetch src pointer
126 add dst_pre_mem=0,in0 // prefetch dest pointer
127 ;;
128(p7) mov ar.lc=cnt // prefetch count
129(p8) mov ar.lc=r0
130(p6) br.cond.dpnt .long_copy
131 ;;
132
133.prefetch:
134 lfetch.fault [src_pre_mem], 128
135 lfetch.fault.excl [dst_pre_mem], 128
136 br.cloop.dptk.few .prefetch
137 ;;
138
139.medium_copy:
140 and tmp=31,in2 // copy length after iteration
141 shr.u r29=in2,5 // number of 32-byte iteration
142 add dst1=8,dst0 // 2nd dest pointer
143 ;;
144 add cnt=-1,r29 // ctop iteration adjustment
145 cmp.eq p10,p0=r29,r0 // do we really need to loop?
146 add src1=8,src0 // 2nd src pointer
147 cmp.le p6,p0=8,tmp
148 ;;
149 cmp.le p7,p0=16,tmp
150 mov ar.lc=cnt // loop setup
151 cmp.eq p16,p17 = r0,r0
152 mov ar.ec=2
153(p10) br.dpnt.few .aligned_src_tail
154 ;;
155 TEXT_ALIGN(32)
1561:
157EX(.ex_handler, (p16) ld8 r34=[src0],16)
158EK(.ex_handler, (p16) ld8 r38=[src1],16)
159EX(.ex_handler, (p17) st8 [dst0]=r33,16)
160EK(.ex_handler, (p17) st8 [dst1]=r37,16)
161 ;;
162EX(.ex_handler, (p16) ld8 r32=[src0],16)
163EK(.ex_handler, (p16) ld8 r36=[src1],16)
164EX(.ex_handler, (p16) st8 [dst0]=r34,16)
165EK(.ex_handler, (p16) st8 [dst1]=r38,16)
166 br.ctop.dptk.few 1b
167 ;;
168
169.aligned_src_tail:
170EX(.ex_handler, (p6) ld8 t1=[src0])
171 mov ar.lc=saved_lc
172 mov ar.pfs=saved_pfs
173EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8)
174 cmp.le p8,p0=24,tmp
175 and r21=-8,tmp
176 ;;
177EX(.ex_hndlr_s, (p8) ld8 t3=[src1])
178EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1
179 and in2=7,tmp // remaining length
180EX(.ex_hndlr_d, (p7) st8 [dst1]=t2,8) // store byte 2
181 add src0=src0,r21 // setting up src pointer
182 add dst0=dst0,r21 // setting up dest pointer
183 ;;
184EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3
185 mov pr=saved_pr,-1
186 br.dptk.many .memcpy_short
187 ;;
188
189/* code taken from copy_page_mck */
190.long_copy:
191 .rotr v[2*PREFETCH_DIST]
192 .rotp p[N]
193
194 mov src_pre_mem = src0
195 mov pr.rot = 0x10000
196 mov ar.ec = 1 // special unrolled loop
197
198 mov dst_pre_mem = dst0
199
200 add src_pre_l2 = 8*8, src0
201 add dst_pre_l2 = 8*8, dst0
202 ;;
203 add src0 = 8, src_pre_mem // first t1 src
204 mov ar.lc = 2*PREFETCH_DIST - 1
205 shr.u cnt=in2,7 // number of lines
206 add src1 = 3*8, src_pre_mem // first t3 src
207 add dst0 = 8, dst_pre_mem // first t1 dst
208 add dst1 = 3*8, dst_pre_mem // first t3 dst
209 ;;
210 and tmp=127,in2 // remaining bytes after this block
211 add cnt = -(2*PREFETCH_DIST) - 1, cnt
212 // same as .line_copy loop, but with all predicated-off instructions removed:
213.prefetch_loop:
214EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0
215EK(.ex_hndlr_lcpy_1, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2
216 br.ctop.sptk .prefetch_loop
217 ;;
218 cmp.eq p16, p0 = r0, r0 // reset p16 to 1
219 mov ar.lc = cnt
220 mov ar.ec = N // # of stages in pipeline
221 ;;
222.line_copy:
223EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0
224EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1
225EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory
226EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2
227 ;;
228EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory
229EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2
230EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2
231EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3
232 ;;
233EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8)
234EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8)
235EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8)
236EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8)
237 ;;
238EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8)
239EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8)
240EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8)
241EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8)
242 ;;
243EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8)
244EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8)
245EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8)
246EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8)
247 ;;
248EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8)
249EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8)
250EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8)
251EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8)
252 ;;
253EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8)
254EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8)
255EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8)
256EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8)
257 ;;
258EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8)
259EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8)
260EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8)
261EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8)
262 br.ctop.sptk .line_copy
263 ;;
264
265 add dst0=-8,dst0
266 add src0=-8,src0
267 mov in2=tmp
268 .restore sp
269 br.sptk.many .medium_copy
270 ;;
271
272#define BLOCK_SIZE 128*32
273#define blocksize r23
274#define curlen r24
275
276// dest is on 8-byte boundary, src is not. We need to do
277// ld8-ld8, shrp, then st8. Max 8 byte copy per cycle.
278.unaligned_src:
279 .prologue
280 .save ar.pfs, saved_pfs
281 alloc saved_pfs=ar.pfs,3,5,0,8
282 .save ar.lc, saved_lc
283 mov saved_lc=ar.lc
284 .save pr, saved_pr
285 mov saved_pr=pr
286 .body
287.4k_block:
288 mov saved_in0=dst0 // need to save all input arguments
289 mov saved_in2=in2
290 mov blocksize=BLOCK_SIZE
291 ;;
292 cmp.lt p6,p7=blocksize,in2
293 mov saved_in1=src0
294 ;;
295(p6) mov in2=blocksize
296 ;;
297 shr.u r21=in2,7 // this much cache line
298 shr.u r22=in2,4 // number of 16-byte iteration
299 and curlen=15,in2 // copy length after iteration
300 and r30=7,src0 // source alignment
301 ;;
302 cmp.lt p7,p8=1,r21
303 add cnt=-1,r21
304 ;;
305
306 add src_pre_mem=0,src0 // prefetch src pointer
307 add dst_pre_mem=0,dst0 // prefetch dest pointer
308 and src0=-8,src0 // 1st src pointer
309(p7) mov ar.lc = cnt
310(p8) mov ar.lc = r0
311 ;;
312 TEXT_ALIGN(32)
3131: lfetch.fault [src_pre_mem], 128
314 lfetch.fault.excl [dst_pre_mem], 128
315 br.cloop.dptk.few 1b
316 ;;
317
318 shladd dst1=r22,3,dst0 // 2nd dest pointer
319 shladd src1=r22,3,src0 // 2nd src pointer
320 cmp.eq p8,p9=r22,r0 // do we really need to loop?
321 cmp.le p6,p7=8,curlen; // have at least 8 byte remaining?
322 add cnt=-1,r22 // ctop iteration adjustment
323 ;;
324EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer
325EK(.ex_handler, (p9) ld8 r37=[src1],8)
326(p8) br.dpnt.few .noloop
327 ;;
328
329// The jump address is calculated based on src alignment. The COPYU
330// macro below need to confine its size to power of two, so an entry
331// can be caulated using shl instead of an expensive multiply. The
332// size is then hard coded by the following #define to match the
333// actual size. This make it somewhat tedious when COPYU macro gets
334// changed and this need to be adjusted to match.
335#define LOOP_SIZE 6
3361:
337 mov r29=ip // jmp_table thread
338 mov ar.lc=cnt
339 ;;
340 add r29=.jump_table - 1b - (.jmp1-.jump_table), r29
341 shl r28=r30, LOOP_SIZE // jmp_table thread
342 mov ar.ec=2 // loop setup
343 ;;
344 add r29=r29,r28 // jmp_table thread
345 cmp.eq p16,p17=r0,r0
346 ;;
347 mov b6=r29 // jmp_table thread
348 ;;
349 br.cond.sptk.few b6
350
351// for 8-15 byte case
352// We will skip the loop, but need to replicate the side effect
353// that the loop produces.
354.noloop:
355EX(.ex_handler, (p6) ld8 r37=[src1],8)
356 add src0=8,src0
357(p6) shl r25=r30,3
358 ;;
359EX(.ex_handler, (p6) ld8 r27=[src1])
360(p6) shr.u r28=r37,r25
361(p6) sub r26=64,r25
362 ;;
363(p6) shl r27=r27,r26
364 ;;
365(p6) or r21=r28,r27
366
367.unaligned_src_tail:
368/* check if we have more than blocksize to copy, if so go back */
369 cmp.gt p8,p0=saved_in2,blocksize
370 ;;
371(p8) add dst0=saved_in0,blocksize
372(p8) add src0=saved_in1,blocksize
373(p8) sub in2=saved_in2,blocksize
374(p8) br.dpnt .4k_block
375 ;;
376
377/* we have up to 15 byte to copy in the tail.
378 * part of work is already done in the jump table code
379 * we are at the following state.
380 * src side:
381 *
382 * xxxxxx xx <----- r21 has xxxxxxxx already
383 * -------- -------- --------
384 * 0 8 16
385 * ^
386 * |
387 * src1
388 *
389 * dst
390 * -------- -------- --------
391 * ^
392 * |
393 * dst1
394 */
395EX(.ex_handler, (p6) st8 [dst1]=r21,8) // more than 8 byte to copy
396(p6) add curlen=-8,curlen // update length
397 mov ar.pfs=saved_pfs
398 ;;
399 mov ar.lc=saved_lc
400 mov pr=saved_pr,-1
401 mov in2=curlen // remaining length
402 mov dst0=dst1 // dest pointer
403 add src0=src1,r30 // forward by src alignment
404 ;;
405
406// 7 byte or smaller.
407.memcpy_short:
408 cmp.le p8,p9 = 1,in2
409 cmp.le p10,p11 = 2,in2
410 cmp.le p12,p13 = 3,in2
411 cmp.le p14,p15 = 4,in2
412 add src1=1,src0 // second src pointer
413 add dst1=1,dst0 // second dest pointer
414 ;;
415
416EX(.ex_handler_short, (p8) ld1 t1=[src0],2)
417EK(.ex_handler_short, (p10) ld1 t2=[src1],2)
418(p9) br.ret.dpnt rp // 0 byte copy
419 ;;
420
421EX(.ex_handler_short, (p8) st1 [dst0]=t1,2)
422EK(.ex_handler_short, (p10) st1 [dst1]=t2,2)
423(p11) br.ret.dpnt rp // 1 byte copy
424
425EX(.ex_handler_short, (p12) ld1 t3=[src0],2)
426EK(.ex_handler_short, (p14) ld1 t4=[src1],2)
427(p13) br.ret.dpnt rp // 2 byte copy
428 ;;
429
430 cmp.le p6,p7 = 5,in2
431 cmp.le p8,p9 = 6,in2
432 cmp.le p10,p11 = 7,in2
433
434EX(.ex_handler_short, (p12) st1 [dst0]=t3,2)
435EK(.ex_handler_short, (p14) st1 [dst1]=t4,2)
436(p15) br.ret.dpnt rp // 3 byte copy
437 ;;
438
439EX(.ex_handler_short, (p6) ld1 t5=[src0],2)
440EK(.ex_handler_short, (p8) ld1 t6=[src1],2)
441(p7) br.ret.dpnt rp // 4 byte copy
442 ;;
443
444EX(.ex_handler_short, (p6) st1 [dst0]=t5,2)
445EK(.ex_handler_short, (p8) st1 [dst1]=t6,2)
446(p9) br.ret.dptk rp // 5 byte copy
447
448EX(.ex_handler_short, (p10) ld1 t7=[src0],2)
449(p11) br.ret.dptk rp // 6 byte copy
450 ;;
451
452EX(.ex_handler_short, (p10) st1 [dst0]=t7,2)
453 br.ret.dptk rp // done all cases
454
455
456/* Align dest to nearest 8-byte boundary. We know we have at
457 * least 7 bytes to copy, enough to crawl to 8-byte boundary.
458 * Actual number of byte to crawl depend on the dest alignment.
459 * 7 byte or less is taken care at .memcpy_short
460
461 * src0 - source even index
462 * src1 - source odd index
463 * dst0 - dest even index
464 * dst1 - dest odd index
465 * r30 - distance to 8-byte boundary
466 */
467
468.align_dest:
469 add src1=1,in1 // source odd index
470 cmp.le p7,p0 = 2,r30 // for .align_dest
471 cmp.le p8,p0 = 3,r30 // for .align_dest
472EX(.ex_handler_short, (p6) ld1 t1=[src0],2)
473 cmp.le p9,p0 = 4,r30 // for .align_dest
474 cmp.le p10,p0 = 5,r30
475 ;;
476EX(.ex_handler_short, (p7) ld1 t2=[src1],2)
477EK(.ex_handler_short, (p8) ld1 t3=[src0],2)
478 cmp.le p11,p0 = 6,r30
479EX(.ex_handler_short, (p6) st1 [dst0] = t1,2)
480 cmp.le p12,p0 = 7,r30
481 ;;
482EX(.ex_handler_short, (p9) ld1 t4=[src1],2)
483EK(.ex_handler_short, (p10) ld1 t5=[src0],2)
484EX(.ex_handler_short, (p7) st1 [dst1] = t2,2)
485EK(.ex_handler_short, (p8) st1 [dst0] = t3,2)
486 ;;
487EX(.ex_handler_short, (p11) ld1 t6=[src1],2)
488EK(.ex_handler_short, (p12) ld1 t7=[src0],2)
489 cmp.eq p6,p7=r28,r29
490EX(.ex_handler_short, (p9) st1 [dst1] = t4,2)
491EK(.ex_handler_short, (p10) st1 [dst0] = t5,2)
492 sub in2=in2,r30
493 ;;
494EX(.ex_handler_short, (p11) st1 [dst1] = t6,2)
495EK(.ex_handler_short, (p12) st1 [dst0] = t7)
496 add dst0=in0,r30 // setup arguments
497 add src0=in1,r30
498(p6) br.cond.dptk .aligned_src
499(p7) br.cond.dpnt .unaligned_src
500 ;;
501
502/* main loop body in jump table format */
503#define COPYU(shift) \
5041: \
505EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \
506EK(.ex_handler, (p16) ld8 r36=[src1],8); \
507 (p17) shrp r35=r33,r34,shift;; /* 1 */ \
508EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \
509 nop.m 0; \
510 (p16) shrp r38=r36,r37,shift; \
511EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \
512EK(.ex_handler, (p17) st8 [dst1]=r39,8); \
513 br.ctop.dptk.few 1b;; \
514 (p7) add src1=-8,src1; /* back out for <8 byte case */ \
515 shrp r21=r22,r38,shift; /* speculative work */ \
516 br.sptk.few .unaligned_src_tail /* branch out of jump table */ \
517 ;;
518 TEXT_ALIGN(32)
519.jump_table:
520 COPYU(8) // unaligned cases
521.jmp1:
522 COPYU(16)
523 COPYU(24)
524 COPYU(32)
525 COPYU(40)
526 COPYU(48)
527 COPYU(56)
528
529#undef A
530#undef B
531#undef C
532#undef D
533
534/*
535 * Due to lack of local tag support in gcc 2.x assembler, it is not clear which
536 * instruction failed in the bundle. The exception algorithm is that we
537 * first figure out the faulting address, then detect if there is any
538 * progress made on the copy, if so, redo the copy from last known copied
539 * location up to the faulting address (exclusive). In the copy_from_user
540 * case, remaining byte in kernel buffer will be zeroed.
541 *
542 * Take copy_from_user as an example, in the code there are multiple loads
543 * in a bundle and those multiple loads could span over two pages, the
544 * faulting address is calculated as page_round_down(max(src0, src1)).
545 * This is based on knowledge that if we can access one byte in a page, we
546 * can access any byte in that page.
547 *
548 * predicate used in the exception handler:
549 * p6-p7: direction
550 * p10-p11: src faulting addr calculation
551 * p12-p13: dst faulting addr calculation
552 */
553
554#define A r19
555#define B r20
556#define C r21
557#define D r22
558#define F r28
559
560#define saved_retval loc0
561#define saved_rtlink loc1
562#define saved_pfs_stack loc2
563
564.ex_hndlr_s:
565 add src0=8,src0
566 br.sptk .ex_handler
567 ;;
568.ex_hndlr_d:
569 add dst0=8,dst0
570 br.sptk .ex_handler
571 ;;
572.ex_hndlr_lcpy_1:
573 mov src1=src_pre_mem
574 mov dst1=dst_pre_mem
575 cmp.gtu p10,p11=src_pre_mem,saved_in1
576 cmp.gtu p12,p13=dst_pre_mem,saved_in0
577 ;;
578(p10) add src0=8,saved_in1
579(p11) mov src0=saved_in1
580(p12) add dst0=8,saved_in0
581(p13) mov dst0=saved_in0
582 br.sptk .ex_handler
583.ex_handler_lcpy:
584 // in line_copy block, the preload addresses should always ahead
585 // of the other two src/dst pointers. Furthermore, src1/dst1 should
586 // always ahead of src0/dst0.
587 mov src1=src_pre_mem
588 mov dst1=dst_pre_mem
589.ex_handler:
590 mov pr=saved_pr,-1 // first restore pr, lc, and pfs
591 mov ar.lc=saved_lc
592 mov ar.pfs=saved_pfs
593 ;;
594.ex_handler_short: // fault occurred in these sections didn't change pr, lc, pfs
595 cmp.ltu p6,p7=saved_in0, saved_in1 // get the copy direction
596 cmp.ltu p10,p11=src0,src1
597 cmp.ltu p12,p13=dst0,dst1
598 fcmp.eq p8,p0=f6,f0 // is it memcpy?
599 mov tmp = dst0
600 ;;
601(p11) mov src1 = src0 // pick the larger of the two
602(p13) mov dst0 = dst1 // make dst0 the smaller one
603(p13) mov dst1 = tmp // and dst1 the larger one
604 ;;
605(p6) dep F = r0,dst1,0,PAGE_SHIFT // usr dst round down to page boundary
606(p7) dep F = r0,src1,0,PAGE_SHIFT // usr src round down to page boundary
607 ;;
608(p6) cmp.le p14,p0=dst0,saved_in0 // no progress has been made on store
609(p7) cmp.le p14,p0=src0,saved_in1 // no progress has been made on load
610 mov retval=saved_in2
611(p8) ld1 tmp=[src1] // force an oops for memcpy call
612(p8) st1 [dst1]=r0 // force an oops for memcpy call
613(p14) br.ret.sptk.many rp
614
615/*
616 * The remaining byte to copy is calculated as:
617 *
618 * A = (faulting_addr - orig_src) -> len to faulting ld address
619 * or
620 * (faulting_addr - orig_dst) -> len to faulting st address
621 * B = (cur_dst - orig_dst) -> len copied so far
622 * C = A - B -> len need to be copied
623 * D = orig_len - A -> len need to be left along
624 */
625(p6) sub A = F, saved_in0
626(p7) sub A = F, saved_in1
627 clrrrb
628 ;;
629 alloc saved_pfs_stack=ar.pfs,3,3,3,0
630 cmp.lt p8,p0=A,r0
631 sub B = dst0, saved_in0 // how many byte copied so far
632 ;;
633(p8) mov A = 0; // A shouldn't be negative, cap it
634 ;;
635 sub C = A, B
636 sub D = saved_in2, A
637 ;;
638 cmp.gt p8,p0=C,r0 // more than 1 byte?
639 mov r8=0
640 mov saved_retval = D
641 mov saved_rtlink = b0
642
643 add out0=saved_in0, B
644 add out1=saved_in1, B
645 mov out2=C
646(p8) br.call.sptk.few b0=__copy_user // recursive call
647 ;;
648
649 add saved_retval=saved_retval,r8 // above might return non-zero value
650 ;;
651
652 mov retval=saved_retval
653 mov ar.pfs=saved_pfs_stack
654 mov b0=saved_rtlink
655 br.ret.sptk.many rp
656
657/* end of McKinley specific optimization */
658END(__copy_user)
659EXPORT_SYMBOL(__copy_user)
1/*
2 * Itanium 2-optimized version of memcpy and copy_user function
3 *
4 * Inputs:
5 * in0: destination address
6 * in1: source address
7 * in2: number of bytes to copy
8 * Output:
9 * for memcpy: return dest
10 * for copy_user: return 0 if success,
11 * or number of byte NOT copied if error occurred.
12 *
13 * Copyright (C) 2002 Intel Corp.
14 * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com>
15 */
16#include <asm/asmmacro.h>
17#include <asm/page.h>
18
19#define EK(y...) EX(y)
20
21/* McKinley specific optimization */
22
23#define retval r8
24#define saved_pfs r31
25#define saved_lc r10
26#define saved_pr r11
27#define saved_in0 r14
28#define saved_in1 r15
29#define saved_in2 r16
30
31#define src0 r2
32#define src1 r3
33#define dst0 r17
34#define dst1 r18
35#define cnt r9
36
37/* r19-r30 are temp for each code section */
38#define PREFETCH_DIST 8
39#define src_pre_mem r19
40#define dst_pre_mem r20
41#define src_pre_l2 r21
42#define dst_pre_l2 r22
43#define t1 r23
44#define t2 r24
45#define t3 r25
46#define t4 r26
47#define t5 t1 // alias!
48#define t6 t2 // alias!
49#define t7 t3 // alias!
50#define n8 r27
51#define t9 t5 // alias!
52#define t10 t4 // alias!
53#define t11 t7 // alias!
54#define t12 t6 // alias!
55#define t14 t10 // alias!
56#define t13 r28
57#define t15 r29
58#define tmp r30
59
60/* defines for long_copy block */
61#define A 0
62#define B (PREFETCH_DIST)
63#define C (B + PREFETCH_DIST)
64#define D (C + 1)
65#define N (D + 1)
66#define Nrot ((N + 7) & ~7)
67
68/* alias */
69#define in0 r32
70#define in1 r33
71#define in2 r34
72
73GLOBAL_ENTRY(memcpy)
74 and r28=0x7,in0
75 and r29=0x7,in1
76 mov f6=f0
77 mov retval=in0
78 br.cond.sptk .common_code
79 ;;
80END(memcpy)
81GLOBAL_ENTRY(__copy_user)
82 .prologue
83// check dest alignment
84 and r28=0x7,in0
85 and r29=0x7,in1
86 mov f6=f1
87 mov saved_in0=in0 // save dest pointer
88 mov saved_in1=in1 // save src pointer
89 mov retval=r0 // initialize return value
90 ;;
91.common_code:
92 cmp.gt p15,p0=8,in2 // check for small size
93 cmp.ne p13,p0=0,r28 // check dest alignment
94 cmp.ne p14,p0=0,r29 // check src alignment
95 add src0=0,in1
96 sub r30=8,r28 // for .align_dest
97 mov saved_in2=in2 // save len
98 ;;
99 add dst0=0,in0
100 add dst1=1,in0 // dest odd index
101 cmp.le p6,p0 = 1,r30 // for .align_dest
102(p15) br.cond.dpnt .memcpy_short
103(p13) br.cond.dpnt .align_dest
104(p14) br.cond.dpnt .unaligned_src
105 ;;
106
107// both dest and src are aligned on 8-byte boundary
108.aligned_src:
109 .save ar.pfs, saved_pfs
110 alloc saved_pfs=ar.pfs,3,Nrot-3,0,Nrot
111 .save pr, saved_pr
112 mov saved_pr=pr
113
114 shr.u cnt=in2,7 // this much cache line
115 ;;
116 cmp.lt p6,p0=2*PREFETCH_DIST,cnt
117 cmp.lt p7,p8=1,cnt
118 .save ar.lc, saved_lc
119 mov saved_lc=ar.lc
120 .body
121 add cnt=-1,cnt
122 add src_pre_mem=0,in1 // prefetch src pointer
123 add dst_pre_mem=0,in0 // prefetch dest pointer
124 ;;
125(p7) mov ar.lc=cnt // prefetch count
126(p8) mov ar.lc=r0
127(p6) br.cond.dpnt .long_copy
128 ;;
129
130.prefetch:
131 lfetch.fault [src_pre_mem], 128
132 lfetch.fault.excl [dst_pre_mem], 128
133 br.cloop.dptk.few .prefetch
134 ;;
135
136.medium_copy:
137 and tmp=31,in2 // copy length after iteration
138 shr.u r29=in2,5 // number of 32-byte iteration
139 add dst1=8,dst0 // 2nd dest pointer
140 ;;
141 add cnt=-1,r29 // ctop iteration adjustment
142 cmp.eq p10,p0=r29,r0 // do we really need to loop?
143 add src1=8,src0 // 2nd src pointer
144 cmp.le p6,p0=8,tmp
145 ;;
146 cmp.le p7,p0=16,tmp
147 mov ar.lc=cnt // loop setup
148 cmp.eq p16,p17 = r0,r0
149 mov ar.ec=2
150(p10) br.dpnt.few .aligned_src_tail
151 ;;
152 TEXT_ALIGN(32)
1531:
154EX(.ex_handler, (p16) ld8 r34=[src0],16)
155EK(.ex_handler, (p16) ld8 r38=[src1],16)
156EX(.ex_handler, (p17) st8 [dst0]=r33,16)
157EK(.ex_handler, (p17) st8 [dst1]=r37,16)
158 ;;
159EX(.ex_handler, (p16) ld8 r32=[src0],16)
160EK(.ex_handler, (p16) ld8 r36=[src1],16)
161EX(.ex_handler, (p16) st8 [dst0]=r34,16)
162EK(.ex_handler, (p16) st8 [dst1]=r38,16)
163 br.ctop.dptk.few 1b
164 ;;
165
166.aligned_src_tail:
167EX(.ex_handler, (p6) ld8 t1=[src0])
168 mov ar.lc=saved_lc
169 mov ar.pfs=saved_pfs
170EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8)
171 cmp.le p8,p0=24,tmp
172 and r21=-8,tmp
173 ;;
174EX(.ex_hndlr_s, (p8) ld8 t3=[src1])
175EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1
176 and in2=7,tmp // remaining length
177EX(.ex_hndlr_d, (p7) st8 [dst1]=t2,8) // store byte 2
178 add src0=src0,r21 // setting up src pointer
179 add dst0=dst0,r21 // setting up dest pointer
180 ;;
181EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3
182 mov pr=saved_pr,-1
183 br.dptk.many .memcpy_short
184 ;;
185
186/* code taken from copy_page_mck */
187.long_copy:
188 .rotr v[2*PREFETCH_DIST]
189 .rotp p[N]
190
191 mov src_pre_mem = src0
192 mov pr.rot = 0x10000
193 mov ar.ec = 1 // special unrolled loop
194
195 mov dst_pre_mem = dst0
196
197 add src_pre_l2 = 8*8, src0
198 add dst_pre_l2 = 8*8, dst0
199 ;;
200 add src0 = 8, src_pre_mem // first t1 src
201 mov ar.lc = 2*PREFETCH_DIST - 1
202 shr.u cnt=in2,7 // number of lines
203 add src1 = 3*8, src_pre_mem // first t3 src
204 add dst0 = 8, dst_pre_mem // first t1 dst
205 add dst1 = 3*8, dst_pre_mem // first t3 dst
206 ;;
207 and tmp=127,in2 // remaining bytes after this block
208 add cnt = -(2*PREFETCH_DIST) - 1, cnt
209 // same as .line_copy loop, but with all predicated-off instructions removed:
210.prefetch_loop:
211EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0
212EK(.ex_hndlr_lcpy_1, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2
213 br.ctop.sptk .prefetch_loop
214 ;;
215 cmp.eq p16, p0 = r0, r0 // reset p16 to 1
216 mov ar.lc = cnt
217 mov ar.ec = N // # of stages in pipeline
218 ;;
219.line_copy:
220EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0
221EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1
222EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory
223EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2
224 ;;
225EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory
226EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2
227EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2
228EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3
229 ;;
230EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8)
231EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8)
232EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8)
233EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8)
234 ;;
235EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8)
236EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8)
237EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8)
238EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8)
239 ;;
240EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8)
241EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8)
242EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8)
243EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8)
244 ;;
245EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8)
246EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8)
247EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8)
248EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8)
249 ;;
250EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8)
251EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8)
252EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8)
253EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8)
254 ;;
255EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8)
256EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8)
257EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8)
258EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8)
259 br.ctop.sptk .line_copy
260 ;;
261
262 add dst0=-8,dst0
263 add src0=-8,src0
264 mov in2=tmp
265 .restore sp
266 br.sptk.many .medium_copy
267 ;;
268
269#define BLOCK_SIZE 128*32
270#define blocksize r23
271#define curlen r24
272
273// dest is on 8-byte boundary, src is not. We need to do
274// ld8-ld8, shrp, then st8. Max 8 byte copy per cycle.
275.unaligned_src:
276 .prologue
277 .save ar.pfs, saved_pfs
278 alloc saved_pfs=ar.pfs,3,5,0,8
279 .save ar.lc, saved_lc
280 mov saved_lc=ar.lc
281 .save pr, saved_pr
282 mov saved_pr=pr
283 .body
284.4k_block:
285 mov saved_in0=dst0 // need to save all input arguments
286 mov saved_in2=in2
287 mov blocksize=BLOCK_SIZE
288 ;;
289 cmp.lt p6,p7=blocksize,in2
290 mov saved_in1=src0
291 ;;
292(p6) mov in2=blocksize
293 ;;
294 shr.u r21=in2,7 // this much cache line
295 shr.u r22=in2,4 // number of 16-byte iteration
296 and curlen=15,in2 // copy length after iteration
297 and r30=7,src0 // source alignment
298 ;;
299 cmp.lt p7,p8=1,r21
300 add cnt=-1,r21
301 ;;
302
303 add src_pre_mem=0,src0 // prefetch src pointer
304 add dst_pre_mem=0,dst0 // prefetch dest pointer
305 and src0=-8,src0 // 1st src pointer
306(p7) mov ar.lc = cnt
307(p8) mov ar.lc = r0
308 ;;
309 TEXT_ALIGN(32)
3101: lfetch.fault [src_pre_mem], 128
311 lfetch.fault.excl [dst_pre_mem], 128
312 br.cloop.dptk.few 1b
313 ;;
314
315 shladd dst1=r22,3,dst0 // 2nd dest pointer
316 shladd src1=r22,3,src0 // 2nd src pointer
317 cmp.eq p8,p9=r22,r0 // do we really need to loop?
318 cmp.le p6,p7=8,curlen; // have at least 8 byte remaining?
319 add cnt=-1,r22 // ctop iteration adjustment
320 ;;
321EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer
322EK(.ex_handler, (p9) ld8 r37=[src1],8)
323(p8) br.dpnt.few .noloop
324 ;;
325
326// The jump address is calculated based on src alignment. The COPYU
327// macro below need to confine its size to power of two, so an entry
328// can be caulated using shl instead of an expensive multiply. The
329// size is then hard coded by the following #define to match the
330// actual size. This make it somewhat tedious when COPYU macro gets
331// changed and this need to be adjusted to match.
332#define LOOP_SIZE 6
3331:
334 mov r29=ip // jmp_table thread
335 mov ar.lc=cnt
336 ;;
337 add r29=.jump_table - 1b - (.jmp1-.jump_table), r29
338 shl r28=r30, LOOP_SIZE // jmp_table thread
339 mov ar.ec=2 // loop setup
340 ;;
341 add r29=r29,r28 // jmp_table thread
342 cmp.eq p16,p17=r0,r0
343 ;;
344 mov b6=r29 // jmp_table thread
345 ;;
346 br.cond.sptk.few b6
347
348// for 8-15 byte case
349// We will skip the loop, but need to replicate the side effect
350// that the loop produces.
351.noloop:
352EX(.ex_handler, (p6) ld8 r37=[src1],8)
353 add src0=8,src0
354(p6) shl r25=r30,3
355 ;;
356EX(.ex_handler, (p6) ld8 r27=[src1])
357(p6) shr.u r28=r37,r25
358(p6) sub r26=64,r25
359 ;;
360(p6) shl r27=r27,r26
361 ;;
362(p6) or r21=r28,r27
363
364.unaligned_src_tail:
365/* check if we have more than blocksize to copy, if so go back */
366 cmp.gt p8,p0=saved_in2,blocksize
367 ;;
368(p8) add dst0=saved_in0,blocksize
369(p8) add src0=saved_in1,blocksize
370(p8) sub in2=saved_in2,blocksize
371(p8) br.dpnt .4k_block
372 ;;
373
374/* we have up to 15 byte to copy in the tail.
375 * part of work is already done in the jump table code
376 * we are at the following state.
377 * src side:
378 *
379 * xxxxxx xx <----- r21 has xxxxxxxx already
380 * -------- -------- --------
381 * 0 8 16
382 * ^
383 * |
384 * src1
385 *
386 * dst
387 * -------- -------- --------
388 * ^
389 * |
390 * dst1
391 */
392EX(.ex_handler, (p6) st8 [dst1]=r21,8) // more than 8 byte to copy
393(p6) add curlen=-8,curlen // update length
394 mov ar.pfs=saved_pfs
395 ;;
396 mov ar.lc=saved_lc
397 mov pr=saved_pr,-1
398 mov in2=curlen // remaining length
399 mov dst0=dst1 // dest pointer
400 add src0=src1,r30 // forward by src alignment
401 ;;
402
403// 7 byte or smaller.
404.memcpy_short:
405 cmp.le p8,p9 = 1,in2
406 cmp.le p10,p11 = 2,in2
407 cmp.le p12,p13 = 3,in2
408 cmp.le p14,p15 = 4,in2
409 add src1=1,src0 // second src pointer
410 add dst1=1,dst0 // second dest pointer
411 ;;
412
413EX(.ex_handler_short, (p8) ld1 t1=[src0],2)
414EK(.ex_handler_short, (p10) ld1 t2=[src1],2)
415(p9) br.ret.dpnt rp // 0 byte copy
416 ;;
417
418EX(.ex_handler_short, (p8) st1 [dst0]=t1,2)
419EK(.ex_handler_short, (p10) st1 [dst1]=t2,2)
420(p11) br.ret.dpnt rp // 1 byte copy
421
422EX(.ex_handler_short, (p12) ld1 t3=[src0],2)
423EK(.ex_handler_short, (p14) ld1 t4=[src1],2)
424(p13) br.ret.dpnt rp // 2 byte copy
425 ;;
426
427 cmp.le p6,p7 = 5,in2
428 cmp.le p8,p9 = 6,in2
429 cmp.le p10,p11 = 7,in2
430
431EX(.ex_handler_short, (p12) st1 [dst0]=t3,2)
432EK(.ex_handler_short, (p14) st1 [dst1]=t4,2)
433(p15) br.ret.dpnt rp // 3 byte copy
434 ;;
435
436EX(.ex_handler_short, (p6) ld1 t5=[src0],2)
437EK(.ex_handler_short, (p8) ld1 t6=[src1],2)
438(p7) br.ret.dpnt rp // 4 byte copy
439 ;;
440
441EX(.ex_handler_short, (p6) st1 [dst0]=t5,2)
442EK(.ex_handler_short, (p8) st1 [dst1]=t6,2)
443(p9) br.ret.dptk rp // 5 byte copy
444
445EX(.ex_handler_short, (p10) ld1 t7=[src0],2)
446(p11) br.ret.dptk rp // 6 byte copy
447 ;;
448
449EX(.ex_handler_short, (p10) st1 [dst0]=t7,2)
450 br.ret.dptk rp // done all cases
451
452
453/* Align dest to nearest 8-byte boundary. We know we have at
454 * least 7 bytes to copy, enough to crawl to 8-byte boundary.
455 * Actual number of byte to crawl depend on the dest alignment.
456 * 7 byte or less is taken care at .memcpy_short
457
458 * src0 - source even index
459 * src1 - source odd index
460 * dst0 - dest even index
461 * dst1 - dest odd index
462 * r30 - distance to 8-byte boundary
463 */
464
465.align_dest:
466 add src1=1,in1 // source odd index
467 cmp.le p7,p0 = 2,r30 // for .align_dest
468 cmp.le p8,p0 = 3,r30 // for .align_dest
469EX(.ex_handler_short, (p6) ld1 t1=[src0],2)
470 cmp.le p9,p0 = 4,r30 // for .align_dest
471 cmp.le p10,p0 = 5,r30
472 ;;
473EX(.ex_handler_short, (p7) ld1 t2=[src1],2)
474EK(.ex_handler_short, (p8) ld1 t3=[src0],2)
475 cmp.le p11,p0 = 6,r30
476EX(.ex_handler_short, (p6) st1 [dst0] = t1,2)
477 cmp.le p12,p0 = 7,r30
478 ;;
479EX(.ex_handler_short, (p9) ld1 t4=[src1],2)
480EK(.ex_handler_short, (p10) ld1 t5=[src0],2)
481EX(.ex_handler_short, (p7) st1 [dst1] = t2,2)
482EK(.ex_handler_short, (p8) st1 [dst0] = t3,2)
483 ;;
484EX(.ex_handler_short, (p11) ld1 t6=[src1],2)
485EK(.ex_handler_short, (p12) ld1 t7=[src0],2)
486 cmp.eq p6,p7=r28,r29
487EX(.ex_handler_short, (p9) st1 [dst1] = t4,2)
488EK(.ex_handler_short, (p10) st1 [dst0] = t5,2)
489 sub in2=in2,r30
490 ;;
491EX(.ex_handler_short, (p11) st1 [dst1] = t6,2)
492EK(.ex_handler_short, (p12) st1 [dst0] = t7)
493 add dst0=in0,r30 // setup arguments
494 add src0=in1,r30
495(p6) br.cond.dptk .aligned_src
496(p7) br.cond.dpnt .unaligned_src
497 ;;
498
499/* main loop body in jump table format */
500#define COPYU(shift) \
5011: \
502EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \
503EK(.ex_handler, (p16) ld8 r36=[src1],8); \
504 (p17) shrp r35=r33,r34,shift;; /* 1 */ \
505EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \
506 nop.m 0; \
507 (p16) shrp r38=r36,r37,shift; \
508EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \
509EK(.ex_handler, (p17) st8 [dst1]=r39,8); \
510 br.ctop.dptk.few 1b;; \
511 (p7) add src1=-8,src1; /* back out for <8 byte case */ \
512 shrp r21=r22,r38,shift; /* speculative work */ \
513 br.sptk.few .unaligned_src_tail /* branch out of jump table */ \
514 ;;
515 TEXT_ALIGN(32)
516.jump_table:
517 COPYU(8) // unaligned cases
518.jmp1:
519 COPYU(16)
520 COPYU(24)
521 COPYU(32)
522 COPYU(40)
523 COPYU(48)
524 COPYU(56)
525
526#undef A
527#undef B
528#undef C
529#undef D
530
531/*
532 * Due to lack of local tag support in gcc 2.x assembler, it is not clear which
533 * instruction failed in the bundle. The exception algorithm is that we
534 * first figure out the faulting address, then detect if there is any
535 * progress made on the copy, if so, redo the copy from last known copied
536 * location up to the faulting address (exclusive). In the copy_from_user
537 * case, remaining byte in kernel buffer will be zeroed.
538 *
539 * Take copy_from_user as an example, in the code there are multiple loads
540 * in a bundle and those multiple loads could span over two pages, the
541 * faulting address is calculated as page_round_down(max(src0, src1)).
542 * This is based on knowledge that if we can access one byte in a page, we
543 * can access any byte in that page.
544 *
545 * predicate used in the exception handler:
546 * p6-p7: direction
547 * p10-p11: src faulting addr calculation
548 * p12-p13: dst faulting addr calculation
549 */
550
551#define A r19
552#define B r20
553#define C r21
554#define D r22
555#define F r28
556
557#define memset_arg0 r32
558#define memset_arg2 r33
559
560#define saved_retval loc0
561#define saved_rtlink loc1
562#define saved_pfs_stack loc2
563
564.ex_hndlr_s:
565 add src0=8,src0
566 br.sptk .ex_handler
567 ;;
568.ex_hndlr_d:
569 add dst0=8,dst0
570 br.sptk .ex_handler
571 ;;
572.ex_hndlr_lcpy_1:
573 mov src1=src_pre_mem
574 mov dst1=dst_pre_mem
575 cmp.gtu p10,p11=src_pre_mem,saved_in1
576 cmp.gtu p12,p13=dst_pre_mem,saved_in0
577 ;;
578(p10) add src0=8,saved_in1
579(p11) mov src0=saved_in1
580(p12) add dst0=8,saved_in0
581(p13) mov dst0=saved_in0
582 br.sptk .ex_handler
583.ex_handler_lcpy:
584 // in line_copy block, the preload addresses should always ahead
585 // of the other two src/dst pointers. Furthermore, src1/dst1 should
586 // always ahead of src0/dst0.
587 mov src1=src_pre_mem
588 mov dst1=dst_pre_mem
589.ex_handler:
590 mov pr=saved_pr,-1 // first restore pr, lc, and pfs
591 mov ar.lc=saved_lc
592 mov ar.pfs=saved_pfs
593 ;;
594.ex_handler_short: // fault occurred in these sections didn't change pr, lc, pfs
595 cmp.ltu p6,p7=saved_in0, saved_in1 // get the copy direction
596 cmp.ltu p10,p11=src0,src1
597 cmp.ltu p12,p13=dst0,dst1
598 fcmp.eq p8,p0=f6,f0 // is it memcpy?
599 mov tmp = dst0
600 ;;
601(p11) mov src1 = src0 // pick the larger of the two
602(p13) mov dst0 = dst1 // make dst0 the smaller one
603(p13) mov dst1 = tmp // and dst1 the larger one
604 ;;
605(p6) dep F = r0,dst1,0,PAGE_SHIFT // usr dst round down to page boundary
606(p7) dep F = r0,src1,0,PAGE_SHIFT // usr src round down to page boundary
607 ;;
608(p6) cmp.le p14,p0=dst0,saved_in0 // no progress has been made on store
609(p7) cmp.le p14,p0=src0,saved_in1 // no progress has been made on load
610 mov retval=saved_in2
611(p8) ld1 tmp=[src1] // force an oops for memcpy call
612(p8) st1 [dst1]=r0 // force an oops for memcpy call
613(p14) br.ret.sptk.many rp
614
615/*
616 * The remaining byte to copy is calculated as:
617 *
618 * A = (faulting_addr - orig_src) -> len to faulting ld address
619 * or
620 * (faulting_addr - orig_dst) -> len to faulting st address
621 * B = (cur_dst - orig_dst) -> len copied so far
622 * C = A - B -> len need to be copied
623 * D = orig_len - A -> len need to be zeroed
624 */
625(p6) sub A = F, saved_in0
626(p7) sub A = F, saved_in1
627 clrrrb
628 ;;
629 alloc saved_pfs_stack=ar.pfs,3,3,3,0
630 cmp.lt p8,p0=A,r0
631 sub B = dst0, saved_in0 // how many byte copied so far
632 ;;
633(p8) mov A = 0; // A shouldn't be negative, cap it
634 ;;
635 sub C = A, B
636 sub D = saved_in2, A
637 ;;
638 cmp.gt p8,p0=C,r0 // more than 1 byte?
639 add memset_arg0=saved_in0, A
640(p6) mov memset_arg2=0 // copy_to_user should not call memset
641(p7) mov memset_arg2=D // copy_from_user need to have kbuf zeroed
642 mov r8=0
643 mov saved_retval = D
644 mov saved_rtlink = b0
645
646 add out0=saved_in0, B
647 add out1=saved_in1, B
648 mov out2=C
649(p8) br.call.sptk.few b0=__copy_user // recursive call
650 ;;
651
652 add saved_retval=saved_retval,r8 // above might return non-zero value
653 cmp.gt p8,p0=memset_arg2,r0 // more than 1 byte?
654 mov out0=memset_arg0 // *s
655 mov out1=r0 // c
656 mov out2=memset_arg2 // n
657(p8) br.call.sptk.few b0=memset
658 ;;
659
660 mov retval=saved_retval
661 mov ar.pfs=saved_pfs_stack
662 mov b0=saved_rtlink
663 br.ret.sptk.many rp
664
665/* end of McKinley specific optimization */
666END(__copy_user)