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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 * 0 if success, or number of byte NOT copied if error occurred.
10 *
11 * Copyright (C) 2002 Intel Corp.
12 * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com>
13 */
14#include <linux/config.h>
15#include <asm/asmmacro.h>
16#include <asm/page.h>
17
18#define EK(y...) EX(y)
19
20/* McKinley specific optimization */
21
22#define retval r8
23#define saved_pfs r31
24#define saved_lc r10
25#define saved_pr r11
26#define saved_in0 r14
27#define saved_in1 r15
28#define saved_in2 r16
29
30#define src0 r2
31#define src1 r3
32#define dst0 r17
33#define dst1 r18
34#define cnt r9
35
36/* r19-r30 are temp for each code section */
37#define PREFETCH_DIST 8
38#define src_pre_mem r19
39#define dst_pre_mem r20
40#define src_pre_l2 r21
41#define dst_pre_l2 r22
42#define t1 r23
43#define t2 r24
44#define t3 r25
45#define t4 r26
46#define t5 t1 // alias!
47#define t6 t2 // alias!
48#define t7 t3 // alias!
49#define n8 r27
50#define t9 t5 // alias!
51#define t10 t4 // alias!
52#define t11 t7 // alias!
53#define t12 t6 // alias!
54#define t14 t10 // alias!
55#define t13 r28
56#define t15 r29
57#define tmp r30
58
59/* defines for long_copy block */
60#define A 0
61#define B (PREFETCH_DIST)
62#define C (B + PREFETCH_DIST)
63#define D (C + 1)
64#define N (D + 1)
65#define Nrot ((N + 7) & ~7)
66
67/* alias */
68#define in0 r32
69#define in1 r33
70#define in2 r34
71
72GLOBAL_ENTRY(memcpy)
73 and r28=0x7,in0
74 and r29=0x7,in1
75 mov f6=f0
76 br.cond.sptk .common_code
77 ;;
78GLOBAL_ENTRY(__copy_user)
79 .prologue
80// check dest alignment
81 and r28=0x7,in0
82 and r29=0x7,in1
83 mov f6=f1
84 mov saved_in0=in0 // save dest pointer
85 mov saved_in1=in1 // save src pointer
86 mov saved_in2=in2 // save len
87 ;;
88.common_code:
89 cmp.gt p15,p0=8,in2 // check for small size
90 cmp.ne p13,p0=0,r28 // check dest alignment
91 cmp.ne p14,p0=0,r29 // check src alignment
92 add src0=0,in1
93 sub r30=8,r28 // for .align_dest
94 mov retval=r0 // initialize return value
95 ;;
96 add dst0=0,in0
97 add dst1=1,in0 // dest odd index
98 cmp.le p6,p0 = 1,r30 // for .align_dest
99(p15) br.cond.dpnt .memcpy_short
100(p13) br.cond.dpnt .align_dest
101(p14) br.cond.dpnt .unaligned_src
102 ;;
103
104// both dest and src are aligned on 8-byte boundary
105.aligned_src:
106 .save ar.pfs, saved_pfs
107 alloc saved_pfs=ar.pfs,3,Nrot-3,0,Nrot
108 .save pr, saved_pr
109 mov saved_pr=pr
110
111 shr.u cnt=in2,7 // this much cache line
112 ;;
113 cmp.lt p6,p0=2*PREFETCH_DIST,cnt
114 cmp.lt p7,p8=1,cnt
115 .save ar.lc, saved_lc
116 mov saved_lc=ar.lc
117 .body
118 add cnt=-1,cnt
119 add src_pre_mem=0,in1 // prefetch src pointer
120 add dst_pre_mem=0,in0 // prefetch dest pointer
121 ;;
122(p7) mov ar.lc=cnt // prefetch count
123(p8) mov ar.lc=r0
124(p6) br.cond.dpnt .long_copy
125 ;;
126
127.prefetch:
128 lfetch.fault [src_pre_mem], 128
129 lfetch.fault.excl [dst_pre_mem], 128
130 br.cloop.dptk.few .prefetch
131 ;;
132
133.medium_copy:
134 and tmp=31,in2 // copy length after iteration
135 shr.u r29=in2,5 // number of 32-byte iteration
136 add dst1=8,dst0 // 2nd dest pointer
137 ;;
138 add cnt=-1,r29 // ctop iteration adjustment
139 cmp.eq p10,p0=r29,r0 // do we really need to loop?
140 add src1=8,src0 // 2nd src pointer
141 cmp.le p6,p0=8,tmp
142 ;;
143 cmp.le p7,p0=16,tmp
144 mov ar.lc=cnt // loop setup
145 cmp.eq p16,p17 = r0,r0
146 mov ar.ec=2
147(p10) br.dpnt.few .aligned_src_tail
148 ;;
149 TEXT_ALIGN(32)
1501:
151EX(.ex_handler, (p16) ld8 r34=[src0],16)
152EK(.ex_handler, (p16) ld8 r38=[src1],16)
153EX(.ex_handler, (p17) st8 [dst0]=r33,16)
154EK(.ex_handler, (p17) st8 [dst1]=r37,16)
155 ;;
156EX(.ex_handler, (p16) ld8 r32=[src0],16)
157EK(.ex_handler, (p16) ld8 r36=[src1],16)
158EX(.ex_handler, (p16) st8 [dst0]=r34,16)
159EK(.ex_handler, (p16) st8 [dst1]=r38,16)
160 br.ctop.dptk.few 1b
161 ;;
162
163.aligned_src_tail:
164EX(.ex_handler, (p6) ld8 t1=[src0])
165 mov ar.lc=saved_lc
166 mov ar.pfs=saved_pfs
167EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8)
168 cmp.le p8,p0=24,tmp
169 and r21=-8,tmp
170 ;;
171EX(.ex_hndlr_s, (p8) ld8 t3=[src1])
172EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1
173 and in2=7,tmp // remaining length
174EX(.ex_hndlr_d, (p7) st8 [dst1]=t2,8) // store byte 2
175 add src0=src0,r21 // setting up src pointer
176 add dst0=dst0,r21 // setting up dest pointer
177 ;;
178EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3
179 mov pr=saved_pr,-1
180 br.dptk.many .memcpy_short
181 ;;
182
183/* code taken from copy_page_mck */
184.long_copy:
185 .rotr v[2*PREFETCH_DIST]
186 .rotp p[N]
187
188 mov src_pre_mem = src0
189 mov pr.rot = 0x10000
190 mov ar.ec = 1 // special unrolled loop
191
192 mov dst_pre_mem = dst0
193
194 add src_pre_l2 = 8*8, src0
195 add dst_pre_l2 = 8*8, dst0
196 ;;
197 add src0 = 8, src_pre_mem // first t1 src
198 mov ar.lc = 2*PREFETCH_DIST - 1
199 shr.u cnt=in2,7 // number of lines
200 add src1 = 3*8, src_pre_mem // first t3 src
201 add dst0 = 8, dst_pre_mem // first t1 dst
202 add dst1 = 3*8, dst_pre_mem // first t3 dst
203 ;;
204 and tmp=127,in2 // remaining bytes after this block
205 add cnt = -(2*PREFETCH_DIST) - 1, cnt
206 // same as .line_copy loop, but with all predicated-off instructions removed:
207.prefetch_loop:
208EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0
209EK(.ex_hndlr_lcpy_1, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2
210 br.ctop.sptk .prefetch_loop
211 ;;
212 cmp.eq p16, p0 = r0, r0 // reset p16 to 1
213 mov ar.lc = cnt
214 mov ar.ec = N // # of stages in pipeline
215 ;;
216.line_copy:
217EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0
218EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1
219EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory
220EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2
221 ;;
222EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory
223EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2
224EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2
225EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3
226 ;;
227EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8)
228EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8)
229EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8)
230EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8)
231 ;;
232EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8)
233EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8)
234EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8)
235EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8)
236 ;;
237EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8)
238EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8)
239EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8)
240EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8)
241 ;;
242EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8)
243EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8)
244EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8)
245EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8)
246 ;;
247EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8)
248EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8)
249EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8)
250EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8)
251 ;;
252EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8)
253EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8)
254EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8)
255EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8)
256 br.ctop.sptk .line_copy
257 ;;
258
259 add dst0=-8,dst0
260 add src0=-8,src0
261 mov in2=tmp
262 .restore sp
263 br.sptk.many .medium_copy
264 ;;
265
266#define BLOCK_SIZE 128*32
267#define blocksize r23
268#define curlen r24
269
270// dest is on 8-byte boundary, src is not. We need to do
271// ld8-ld8, shrp, then st8. Max 8 byte copy per cycle.
272.unaligned_src:
273 .prologue
274 .save ar.pfs, saved_pfs
275 alloc saved_pfs=ar.pfs,3,5,0,8
276 .save ar.lc, saved_lc
277 mov saved_lc=ar.lc
278 .save pr, saved_pr
279 mov saved_pr=pr
280 .body
281.4k_block:
282 mov saved_in0=dst0 // need to save all input arguments
283 mov saved_in2=in2
284 mov blocksize=BLOCK_SIZE
285 ;;
286 cmp.lt p6,p7=blocksize,in2
287 mov saved_in1=src0
288 ;;
289(p6) mov in2=blocksize
290 ;;
291 shr.u r21=in2,7 // this much cache line
292 shr.u r22=in2,4 // number of 16-byte iteration
293 and curlen=15,in2 // copy length after iteration
294 and r30=7,src0 // source alignment
295 ;;
296 cmp.lt p7,p8=1,r21
297 add cnt=-1,r21
298 ;;
299
300 add src_pre_mem=0,src0 // prefetch src pointer
301 add dst_pre_mem=0,dst0 // prefetch dest pointer
302 and src0=-8,src0 // 1st src pointer
303(p7) mov ar.lc = r21
304(p8) mov ar.lc = r0
305 ;;
306 TEXT_ALIGN(32)
3071: lfetch.fault [src_pre_mem], 128
308 lfetch.fault.excl [dst_pre_mem], 128
309 br.cloop.dptk.few 1b
310 ;;
311
312 shladd dst1=r22,3,dst0 // 2nd dest pointer
313 shladd src1=r22,3,src0 // 2nd src pointer
314 cmp.eq p8,p9=r22,r0 // do we really need to loop?
315 cmp.le p6,p7=8,curlen; // have at least 8 byte remaining?
316 add cnt=-1,r22 // ctop iteration adjustment
317 ;;
318EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer
319EK(.ex_handler, (p9) ld8 r37=[src1],8)
320(p8) br.dpnt.few .noloop
321 ;;
322
323// The jump address is calculated based on src alignment. The COPYU
324// macro below need to confine its size to power of two, so an entry
325// can be caulated using shl instead of an expensive multiply. The
326// size is then hard coded by the following #define to match the
327// actual size. This make it somewhat tedious when COPYU macro gets
328// changed and this need to be adjusted to match.
329#define LOOP_SIZE 6
3301:
331 mov r29=ip // jmp_table thread
332 mov ar.lc=cnt
333 ;;
334 add r29=.jump_table - 1b - (.jmp1-.jump_table), r29
335 shl r28=r30, LOOP_SIZE // jmp_table thread
336 mov ar.ec=2 // loop setup
337 ;;
338 add r29=r29,r28 // jmp_table thread
339 cmp.eq p16,p17=r0,r0
340 ;;
341 mov b6=r29 // jmp_table thread
342 ;;
343 br.cond.sptk.few b6
344
345// for 8-15 byte case
346// We will skip the loop, but need to replicate the side effect
347// that the loop produces.
348.noloop:
349EX(.ex_handler, (p6) ld8 r37=[src1],8)
350 add src0=8,src0
351(p6) shl r25=r30,3
352 ;;
353EX(.ex_handler, (p6) ld8 r27=[src1])
354(p6) shr.u r28=r37,r25
355(p6) sub r26=64,r25
356 ;;
357(p6) shl r27=r27,r26
358 ;;
359(p6) or r21=r28,r27
360
361.unaligned_src_tail:
362/* check if we have more than blocksize to copy, if so go back */
363 cmp.gt p8,p0=saved_in2,blocksize
364 ;;
365(p8) add dst0=saved_in0,blocksize
366(p8) add src0=saved_in1,blocksize
367(p8) sub in2=saved_in2,blocksize
368(p8) br.dpnt .4k_block
369 ;;
370
371/* we have up to 15 byte to copy in the tail.
372 * part of work is already done in the jump table code
373 * we are at the following state.
374 * src side:
375 *
376 * xxxxxx xx <----- r21 has xxxxxxxx already
377 * -------- -------- --------
378 * 0 8 16
379 * ^
380 * |
381 * src1
382 *
383 * dst
384 * -------- -------- --------
385 * ^
386 * |
387 * dst1
388 */
389EX(.ex_handler, (p6) st8 [dst1]=r21,8) // more than 8 byte to copy
390(p6) add curlen=-8,curlen // update length
391 mov ar.pfs=saved_pfs
392 ;;
393 mov ar.lc=saved_lc
394 mov pr=saved_pr,-1
395 mov in2=curlen // remaining length
396 mov dst0=dst1 // dest pointer
397 add src0=src1,r30 // forward by src alignment
398 ;;
399
400// 7 byte or smaller.
401.memcpy_short:
402 cmp.le p8,p9 = 1,in2
403 cmp.le p10,p11 = 2,in2
404 cmp.le p12,p13 = 3,in2
405 cmp.le p14,p15 = 4,in2
406 add src1=1,src0 // second src pointer
407 add dst1=1,dst0 // second dest pointer
408 ;;
409
410EX(.ex_handler_short, (p8) ld1 t1=[src0],2)
411EK(.ex_handler_short, (p10) ld1 t2=[src1],2)
412(p9) br.ret.dpnt rp // 0 byte copy
413 ;;
414
415EX(.ex_handler_short, (p8) st1 [dst0]=t1,2)
416EK(.ex_handler_short, (p10) st1 [dst1]=t2,2)
417(p11) br.ret.dpnt rp // 1 byte copy
418
419EX(.ex_handler_short, (p12) ld1 t3=[src0],2)
420EK(.ex_handler_short, (p14) ld1 t4=[src1],2)
421(p13) br.ret.dpnt rp // 2 byte copy
422 ;;
423
424 cmp.le p6,p7 = 5,in2
425 cmp.le p8,p9 = 6,in2
426 cmp.le p10,p11 = 7,in2
427
428EX(.ex_handler_short, (p12) st1 [dst0]=t3,2)
429EK(.ex_handler_short, (p14) st1 [dst1]=t4,2)
430(p15) br.ret.dpnt rp // 3 byte copy
431 ;;
432
433EX(.ex_handler_short, (p6) ld1 t5=[src0],2)
434EK(.ex_handler_short, (p8) ld1 t6=[src1],2)
435(p7) br.ret.dpnt rp // 4 byte copy
436 ;;
437
438EX(.ex_handler_short, (p6) st1 [dst0]=t5,2)
439EK(.ex_handler_short, (p8) st1 [dst1]=t6,2)
440(p9) br.ret.dptk rp // 5 byte copy
441
442EX(.ex_handler_short, (p10) ld1 t7=[src0],2)
443(p11) br.ret.dptk rp // 6 byte copy
444 ;;
445
446EX(.ex_handler_short, (p10) st1 [dst0]=t7,2)
447 br.ret.dptk rp // done all cases
448
449
450/* Align dest to nearest 8-byte boundary. We know we have at
451 * least 7 bytes to copy, enough to crawl to 8-byte boundary.
452 * Actual number of byte to crawl depend on the dest alignment.
453 * 7 byte or less is taken care at .memcpy_short
454
455 * src0 - source even index
456 * src1 - source odd index
457 * dst0 - dest even index
458 * dst1 - dest odd index
459 * r30 - distance to 8-byte boundary
460 */
461
462.align_dest:
463 add src1=1,in1 // source odd index
464 cmp.le p7,p0 = 2,r30 // for .align_dest
465 cmp.le p8,p0 = 3,r30 // for .align_dest
466EX(.ex_handler_short, (p6) ld1 t1=[src0],2)
467 cmp.le p9,p0 = 4,r30 // for .align_dest
468 cmp.le p10,p0 = 5,r30
469 ;;
470EX(.ex_handler_short, (p7) ld1 t2=[src1],2)
471EK(.ex_handler_short, (p8) ld1 t3=[src0],2)
472 cmp.le p11,p0 = 6,r30
473EX(.ex_handler_short, (p6) st1 [dst0] = t1,2)
474 cmp.le p12,p0 = 7,r30
475 ;;
476EX(.ex_handler_short, (p9) ld1 t4=[src1],2)
477EK(.ex_handler_short, (p10) ld1 t5=[src0],2)
478EX(.ex_handler_short, (p7) st1 [dst1] = t2,2)
479EK(.ex_handler_short, (p8) st1 [dst0] = t3,2)
480 ;;
481EX(.ex_handler_short, (p11) ld1 t6=[src1],2)
482EK(.ex_handler_short, (p12) ld1 t7=[src0],2)
483 cmp.eq p6,p7=r28,r29
484EX(.ex_handler_short, (p9) st1 [dst1] = t4,2)
485EK(.ex_handler_short, (p10) st1 [dst0] = t5,2)
486 sub in2=in2,r30
487 ;;
488EX(.ex_handler_short, (p11) st1 [dst1] = t6,2)
489EK(.ex_handler_short, (p12) st1 [dst0] = t7)
490 add dst0=in0,r30 // setup arguments
491 add src0=in1,r30
492(p6) br.cond.dptk .aligned_src
493(p7) br.cond.dpnt .unaligned_src
494 ;;
495
496/* main loop body in jump table format */
497#define COPYU(shift) \
4981: \
499EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \
500EK(.ex_handler, (p16) ld8 r36=[src1],8); \
501 (p17) shrp r35=r33,r34,shift;; /* 1 */ \
502EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \
503 nop.m 0; \
504 (p16) shrp r38=r36,r37,shift; \
505EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \
506EK(.ex_handler, (p17) st8 [dst1]=r39,8); \
507 br.ctop.dptk.few 1b;; \
508 (p7) add src1=-8,src1; /* back out for <8 byte case */ \
509 shrp r21=r22,r38,shift; /* speculative work */ \
510 br.sptk.few .unaligned_src_tail /* branch out of jump table */ \
511 ;;
512 TEXT_ALIGN(32)
513.jump_table:
514 COPYU(8) // unaligned cases
515.jmp1:
516 COPYU(16)
517 COPYU(24)
518 COPYU(32)
519 COPYU(40)
520 COPYU(48)
521 COPYU(56)
522
523#undef A
524#undef B
525#undef C
526#undef D
527END(memcpy)
528
529/*
530 * Due to lack of local tag support in gcc 2.x assembler, it is not clear which
531 * instruction failed in the bundle. The exception algorithm is that we
532 * first figure out the faulting address, then detect if there is any
533 * progress made on the copy, if so, redo the copy from last known copied
534 * location up to the faulting address (exclusive). In the copy_from_user
535 * case, remaining byte in kernel buffer will be zeroed.
536 *
537 * Take copy_from_user as an example, in the code there are multiple loads
538 * in a bundle and those multiple loads could span over two pages, the
539 * faulting address is calculated as page_round_down(max(src0, src1)).
540 * This is based on knowledge that if we can access one byte in a page, we
541 * can access any byte in that page.
542 *
543 * predicate used in the exception handler:
544 * p6-p7: direction
545 * p10-p11: src faulting addr calculation
546 * p12-p13: dst faulting addr calculation
547 */
548
549#define A r19
550#define B r20
551#define C r21
552#define D r22
553#define F r28
554
555#define memset_arg0 r32
556#define memset_arg2 r33
557
558#define saved_retval loc0
559#define saved_rtlink loc1
560#define saved_pfs_stack loc2
561
562.ex_hndlr_s:
563 add src0=8,src0
564 br.sptk .ex_handler
565 ;;
566.ex_hndlr_d:
567 add dst0=8,dst0
568 br.sptk .ex_handler
569 ;;
570.ex_hndlr_lcpy_1:
571 mov src1=src_pre_mem
572 mov dst1=dst_pre_mem
573 cmp.gtu p10,p11=src_pre_mem,saved_in1
574 cmp.gtu p12,p13=dst_pre_mem,saved_in0
575 ;;
576(p10) add src0=8,saved_in1
577(p11) mov src0=saved_in1
578(p12) add dst0=8,saved_in0
579(p13) mov dst0=saved_in0
580 br.sptk .ex_handler
581.ex_handler_lcpy:
582 // in line_copy block, the preload addresses should always ahead
583 // of the other two src/dst pointers. Furthermore, src1/dst1 should
584 // always ahead of src0/dst0.
585 mov src1=src_pre_mem
586 mov dst1=dst_pre_mem
587.ex_handler:
588 mov pr=saved_pr,-1 // first restore pr, lc, and pfs
589 mov ar.lc=saved_lc
590 mov ar.pfs=saved_pfs
591 ;;
592.ex_handler_short: // fault occurred in these sections didn't change pr, lc, pfs
593 cmp.ltu p6,p7=saved_in0, saved_in1 // get the copy direction
594 cmp.ltu p10,p11=src0,src1
595 cmp.ltu p12,p13=dst0,dst1
596 fcmp.eq p8,p0=f6,f0 // is it memcpy?
597 mov tmp = dst0
598 ;;
599(p11) mov src1 = src0 // pick the larger of the two
600(p13) mov dst0 = dst1 // make dst0 the smaller one
601(p13) mov dst1 = tmp // and dst1 the larger one
602 ;;
603(p6) dep F = r0,dst1,0,PAGE_SHIFT // usr dst round down to page boundary
604(p7) dep F = r0,src1,0,PAGE_SHIFT // usr src round down to page boundary
605 ;;
606(p6) cmp.le p14,p0=dst0,saved_in0 // no progress has been made on store
607(p7) cmp.le p14,p0=src0,saved_in1 // no progress has been made on load
608 mov retval=saved_in2
609(p8) ld1 tmp=[src1] // force an oops for memcpy call
610(p8) st1 [dst1]=r0 // force an oops for memcpy call
611(p14) br.ret.sptk.many rp
612
613/*
614 * The remaining byte to copy is calculated as:
615 *
616 * A = (faulting_addr - orig_src) -> len to faulting ld address
617 * or
618 * (faulting_addr - orig_dst) -> len to faulting st address
619 * B = (cur_dst - orig_dst) -> len copied so far
620 * C = A - B -> len need to be copied
621 * D = orig_len - A -> len need to be zeroed
622 */
623(p6) sub A = F, saved_in0
624(p7) sub A = F, saved_in1
625 clrrrb
626 ;;
627 alloc saved_pfs_stack=ar.pfs,3,3,3,0
628 sub B = dst0, saved_in0 // how many byte copied so far
629 ;;
630 sub C = A, B
631 sub D = saved_in2, A
632 ;;
633 cmp.gt p8,p0=C,r0 // more than 1 byte?
634 add memset_arg0=saved_in0, A
635(p6) mov memset_arg2=0 // copy_to_user should not call memset
636(p7) mov memset_arg2=D // copy_from_user need to have kbuf zeroed
637 mov r8=0
638 mov saved_retval = D
639 mov saved_rtlink = b0
640
641 add out0=saved_in0, B
642 add out1=saved_in1, B
643 mov out2=C
644(p8) br.call.sptk.few b0=__copy_user // recursive call
645 ;;
646
647 add saved_retval=saved_retval,r8 // above might return non-zero value
648 cmp.gt p8,p0=memset_arg2,r0 // more than 1 byte?
649 mov out0=memset_arg0 // *s
650 mov out1=r0 // c
651 mov out2=memset_arg2 // n
652(p8) br.call.sptk.few b0=memset
653 ;;
654
655 mov retval=saved_retval
656 mov ar.pfs=saved_pfs_stack
657 mov b0=saved_rtlink
658 br.ret.sptk.many rp
659
660/* end of McKinley specific optimization */
661END(__copy_user)