| blob | ab0f8763972954117b0ac6a7dc3ac120d6e042c5 |
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>
19 #define EK(y...) EX(y)
21 /* McKinley specific optimization */
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
31 #define src0 r2
32 #define src1 r3
33 #define dst0 r17
34 #define dst1 r18
35 #define cnt r9
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
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)
68 /* alias */
69 #define in0 r32
70 #define in1 r33
71 #define in2 r34
73 GLOBAL_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 ;;
80 END(memcpy)
81 GLOBAL_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 ;;
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
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 ;;
130 .prefetch:
131 lfetch.fault [src_pre_mem], 128
132 lfetch.fault.excl [dst_pre_mem], 128
133 br.cloop.dptk.few .prefetch
134 ;;
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)
153 1:
154 EX(.ex_handler, (p16) ld8 r34=[src0],16)
155 EK(.ex_handler, (p16) ld8 r38=[src1],16)
156 EX(.ex_handler, (p17) st8 [dst0]=r33,16)
157 EK(.ex_handler, (p17) st8 [dst1]=r37,16)
158 ;;
159 EX(.ex_handler, (p16) ld8 r32=[src0],16)
160 EK(.ex_handler, (p16) ld8 r36=[src1],16)
161 EX(.ex_handler, (p16) st8 [dst0]=r34,16)
162 EK(.ex_handler, (p16) st8 [dst1]=r38,16)
163 br.ctop.dptk.few 1b
164 ;;
166 .aligned_src_tail:
167 EX(.ex_handler, (p6) ld8 t1=[src0])
168 mov ar.lc=saved_lc
169 mov ar.pfs=saved_pfs
170 EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8)
171 cmp.le p8,p0=24,tmp
172 and r21=-8,tmp
173 ;;
174 EX(.ex_hndlr_s, (p8) ld8 t3=[src1])
175 EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1
176 and in2=7,tmp // remaining length
177 EX(.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 ;;
181 EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3
182 mov pr=saved_pr,-1
183 br.dptk.many .memcpy_short
184 ;;
186 /* code taken from copy_page_mck */
187 .long_copy:
188 .rotr v[2*PREFETCH_DIST]
189 .rotp p[N]
191 mov src_pre_mem = src0
192 mov pr.rot = 0x10000
193 mov ar.ec = 1 // special unrolled loop
195 mov dst_pre_mem = dst0
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:
211 EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0
212 EK(.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:
220 EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0
221 EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1
222 EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory
223 EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2
224 ;;
225 EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory
226 EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2
227 EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2
228 EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3
229 ;;
230 EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8)
231 EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8)
232 EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8)
233 EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8)
234 ;;
235 EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8)
236 EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8)
237 EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8)
238 EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8)
239 ;;
240 EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8)
241 EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8)
242 EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8)
243 EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8)
244 ;;
245 EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8)
246 EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8)
247 EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8)
248 EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8)
249 ;;
250 EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8)
251 EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8)
252 EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8)
253 EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8)
254 ;;
255 EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8)
256 EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8)
257 EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8)
258 EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8)
259 br.ctop.sptk .line_copy
260 ;;
262 add dst0=-8,dst0
263 add src0=-8,src0
264 mov in2=tmp
265 .restore sp
266 br.sptk.many .medium_copy
267 ;;
269 #define BLOCK_SIZE 128*32
270 #define blocksize r23
271 #define curlen r24
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 ;;
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)
310 1: lfetch.fault [src_pre_mem], 128
311 lfetch.fault.excl [dst_pre_mem], 128
312 br.cloop.dptk.few 1b
313 ;;
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 ;;
321 EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer
322 EK(.ex_handler, (p9) ld8 r37=[src1],8)
323 (p8) br.dpnt.few .noloop
324 ;;
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
333 1:
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
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:
352 EX(.ex_handler, (p6) ld8 r37=[src1],8)
353 add src0=8,src0
354 (p6) shl r25=r30,3
355 ;;
356 EX(.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
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 ;;
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 */
392 EX(.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 ;;
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 ;;
413 EX(.ex_handler_short, (p8) ld1 t1=[src0],2)
414 EK(.ex_handler_short, (p10) ld1 t2=[src1],2)
415 (p9) br.ret.dpnt rp // 0 byte copy
416 ;;
418 EX(.ex_handler_short, (p8) st1 [dst0]=t1,2)
419 EK(.ex_handler_short, (p10) st1 [dst1]=t2,2)
420 (p11) br.ret.dpnt rp // 1 byte copy
422 EX(.ex_handler_short, (p12) ld1 t3=[src0],2)
423 EK(.ex_handler_short, (p14) ld1 t4=[src1],2)
424 (p13) br.ret.dpnt rp // 2 byte copy
425 ;;
427 cmp.le p6,p7 = 5,in2
428 cmp.le p8,p9 = 6,in2
429 cmp.le p10,p11 = 7,in2
431 EX(.ex_handler_short, (p12) st1 [dst0]=t3,2)
432 EK(.ex_handler_short, (p14) st1 [dst1]=t4,2)
433 (p15) br.ret.dpnt rp // 3 byte copy
434 ;;
436 EX(.ex_handler_short, (p6) ld1 t5=[src0],2)
437 EK(.ex_handler_short, (p8) ld1 t6=[src1],2)
438 (p7) br.ret.dpnt rp // 4 byte copy
439 ;;
441 EX(.ex_handler_short, (p6) st1 [dst0]=t5,2)
442 EK(.ex_handler_short, (p8) st1 [dst1]=t6,2)
443 (p9) br.ret.dptk rp // 5 byte copy
445 EX(.ex_handler_short, (p10) ld1 t7=[src0],2)
446 (p11) br.ret.dptk rp // 6 byte copy
447 ;;
449 EX(.ex_handler_short, (p10) st1 [dst0]=t7,2)
450 br.ret.dptk rp // done all cases
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
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 */
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
469 EX(.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 ;;
473 EX(.ex_handler_short, (p7) ld1 t2=[src1],2)
474 EK(.ex_handler_short, (p8) ld1 t3=[src0],2)
475 cmp.le p11,p0 = 6,r30
476 EX(.ex_handler_short, (p6) st1 [dst0] = t1,2)
477 cmp.le p12,p0 = 7,r30
478 ;;
479 EX(.ex_handler_short, (p9) ld1 t4=[src1],2)
480 EK(.ex_handler_short, (p10) ld1 t5=[src0],2)
481 EX(.ex_handler_short, (p7) st1 [dst1] = t2,2)
482 EK(.ex_handler_short, (p8) st1 [dst0] = t3,2)
483 ;;
484 EX(.ex_handler_short, (p11) ld1 t6=[src1],2)
485 EK(.ex_handler_short, (p12) ld1 t7=[src0],2)
486 cmp.eq p6,p7=r28,r29
487 EX(.ex_handler_short, (p9) st1 [dst1] = t4,2)
488 EK(.ex_handler_short, (p10) st1 [dst0] = t5,2)
489 sub in2=in2,r30
490 ;;
491 EX(.ex_handler_short, (p11) st1 [dst1] = t6,2)
492 EK(.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 ;;
499 /* main loop body in jump table format */
500 #define COPYU(shift) \
501 1: \
502 EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \
503 EK(.ex_handler, (p16) ld8 r36=[src1],8); \
504 (p17) shrp r35=r33,r34,shift;; /* 1 */ \
505 EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \
506 nop.m 0; \
507 (p16) shrp r38=r36,r37,shift; \
508 EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \
509 EK(.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)
526 #undef A
527 #undef B
528 #undef C
529 #undef D
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 */
551 #define A r19
552 #define B r20
553 #define C r21
554 #define D r22
555 #define F r28
557 #define memset_arg0 r32
558 #define memset_arg2 r33
560 #define saved_retval loc0
561 #define saved_rtlink loc1
562 #define saved_pfs_stack loc2
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
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
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 ;;
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 ;;
660 mov retval=saved_retval
661 mov ar.pfs=saved_pfs_stack
662 mov b0=saved_rtlink
663 br.ret.sptk.many rp
665 /* end of McKinley specific optimization */
666 END(__copy_user)