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#include <asm/export.h> 19 20#define EK(y...) EX(y) 21 22/* McKinley specific optimization */ 23 24#define retval r8 25#define saved_pfs r31 26#define saved_lc r10 27#define saved_pr r11 28#define saved_in0 r14 29#define saved_in1 r15 30#define saved_in2 r16 31 32#define src0 r2 33#define src1 r3 34#define dst0 r17 35#define dst1 r18 36#define cnt r9 37 38/* r19-r30 are temp for each code section */ 39#define PREFETCH_DIST 8 40#define src_pre_mem r19 41#define dst_pre_mem r20 42#define src_pre_l2 r21 43#define dst_pre_l2 r22 44#define t1 r23 45#define t2 r24 46#define t3 r25 47#define t4 r26 48#define t5 t1 // alias! 49#define t6 t2 // alias! 50#define t7 t3 // alias! 51#define n8 r27 52#define t9 t5 // alias! 53#define t10 t4 // alias! 54#define t11 t7 // alias! 55#define t12 t6 // alias! 56#define t14 t10 // alias! 57#define t13 r28 58#define t15 r29 59#define tmp r30 60 61/* defines for long_copy block */ 62#define A 0 63#define B (PREFETCH_DIST) 64#define C (B + PREFETCH_DIST) 65#define D (C + 1) 66#define N (D + 1) 67#define Nrot ((N + 7) & ~7) 68 69/* alias */ 70#define in0 r32 71#define in1 r33 72#define in2 r34 73 74GLOBAL_ENTRY(memcpy) 75 and r28=0x7,in0 76 and r29=0x7,in1 77 mov f6=f0 78 mov retval=in0 79 br.cond.sptk .common_code 80 ;; 81END(memcpy) 82EXPORT_SYMBOL(memcpy) 83GLOBAL_ENTRY(__copy_user) 84 .prologue 85// check dest alignment 86 and r28=0x7,in0 87 and r29=0x7,in1 88 mov f6=f1 89 mov saved_in0=in0 // save dest pointer 90 mov saved_in1=in1 // save src pointer 91 mov retval=r0 // initialize return value 92 ;; 93.common_code: 94 cmp.gt p15,p0=8,in2 // check for small size 95 cmp.ne p13,p0=0,r28 // check dest alignment 96 cmp.ne p14,p0=0,r29 // check src alignment 97 add src0=0,in1 98 sub r30=8,r28 // for .align_dest 99 mov saved_in2=in2 // save len 100 ;; 101 add dst0=0,in0 102 add dst1=1,in0 // dest odd index 103 cmp.le p6,p0 = 1,r30 // for .align_dest 104(p15) br.cond.dpnt .memcpy_short 105(p13) br.cond.dpnt .align_dest 106(p14) br.cond.dpnt .unaligned_src 107 ;; 108 109// both dest and src are aligned on 8-byte boundary 110.aligned_src: 111 .save ar.pfs, saved_pfs 112 alloc saved_pfs=ar.pfs,3,Nrot-3,0,Nrot 113 .save pr, saved_pr 114 mov saved_pr=pr 115 116 shr.u cnt=in2,7 // this much cache line 117 ;; 118 cmp.lt p6,p0=2*PREFETCH_DIST,cnt 119 cmp.lt p7,p8=1,cnt 120 .save ar.lc, saved_lc 121 mov saved_lc=ar.lc 122 .body 123 add cnt=-1,cnt 124 add src_pre_mem=0,in1 // prefetch src pointer 125 add dst_pre_mem=0,in0 // prefetch dest pointer 126 ;; 127(p7) mov ar.lc=cnt // prefetch count 128(p8) mov ar.lc=r0 129(p6) br.cond.dpnt .long_copy 130 ;; 131 132.prefetch: 133 lfetch.fault [src_pre_mem], 128 134 lfetch.fault.excl [dst_pre_mem], 128 135 br.cloop.dptk.few .prefetch 136 ;; 137 138.medium_copy: 139 and tmp=31,in2 // copy length after iteration 140 shr.u r29=in2,5 // number of 32-byte iteration 141 add dst1=8,dst0 // 2nd dest pointer 142 ;; 143 add cnt=-1,r29 // ctop iteration adjustment 144 cmp.eq p10,p0=r29,r0 // do we really need to loop? 145 add src1=8,src0 // 2nd src pointer 146 cmp.le p6,p0=8,tmp 147 ;; 148 cmp.le p7,p0=16,tmp 149 mov ar.lc=cnt // loop setup 150 cmp.eq p16,p17 = r0,r0 151 mov ar.ec=2 152(p10) br.dpnt.few .aligned_src_tail 153 ;; 154 TEXT_ALIGN(32) 1551: 156EX(.ex_handler, (p16) ld8 r34=[src0],16) 157EK(.ex_handler, (p16) ld8 r38=[src1],16) 158EX(.ex_handler, (p17) st8 [dst0]=r33,16) 159EK(.ex_handler, (p17) st8 [dst1]=r37,16) 160 ;; 161EX(.ex_handler, (p16) ld8 r32=[src0],16) 162EK(.ex_handler, (p16) ld8 r36=[src1],16) 163EX(.ex_handler, (p16) st8 [dst0]=r34,16) 164EK(.ex_handler, (p16) st8 [dst1]=r38,16) 165 br.ctop.dptk.few 1b 166 ;; 167 168.aligned_src_tail: 169EX(.ex_handler, (p6) ld8 t1=[src0]) 170 mov ar.lc=saved_lc 171 mov ar.pfs=saved_pfs 172EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8) 173 cmp.le p8,p0=24,tmp 174 and r21=-8,tmp 175 ;; 176EX(.ex_hndlr_s, (p8) ld8 t3=[src1]) 177EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1 178 and in2=7,tmp // remaining length 179EX(.ex_hndlr_d, (p7) st8 [dst1]=t2,8) // store byte 2 180 add src0=src0,r21 // setting up src pointer 181 add dst0=dst0,r21 // setting up dest pointer 182 ;; 183EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3 184 mov pr=saved_pr,-1 185 br.dptk.many .memcpy_short 186 ;; 187 188/* code taken from copy_page_mck */ 189.long_copy: 190 .rotr v[2*PREFETCH_DIST] 191 .rotp p[N] 192 193 mov src_pre_mem = src0 194 mov pr.rot = 0x10000 195 mov ar.ec = 1 // special unrolled loop 196 197 mov dst_pre_mem = dst0 198 199 add src_pre_l2 = 8*8, src0 200 add dst_pre_l2 = 8*8, dst0 201 ;; 202 add src0 = 8, src_pre_mem // first t1 src 203 mov ar.lc = 2*PREFETCH_DIST - 1 204 shr.u cnt=in2,7 // number of lines 205 add src1 = 3*8, src_pre_mem // first t3 src 206 add dst0 = 8, dst_pre_mem // first t1 dst 207 add dst1 = 3*8, dst_pre_mem // first t3 dst 208 ;; 209 and tmp=127,in2 // remaining bytes after this block 210 add cnt = -(2*PREFETCH_DIST) - 1, cnt 211 // same as .line_copy loop, but with all predicated-off instructions removed: 212.prefetch_loop: 213EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 214EK(.ex_hndlr_lcpy_1, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 215 br.ctop.sptk .prefetch_loop 216 ;; 217 cmp.eq p16, p0 = r0, r0 // reset p16 to 1 218 mov ar.lc = cnt 219 mov ar.ec = N // # of stages in pipeline 220 ;; 221.line_copy: 222EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0 223EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1 224EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory 225EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2 226 ;; 227EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory 228EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2 229EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2 230EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3 231 ;; 232EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8) 233EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8) 234EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8) 235EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8) 236 ;; 237EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8) 238EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8) 239EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8) 240EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8) 241 ;; 242EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8) 243EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8) 244EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8) 245EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8) 246 ;; 247EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8) 248EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8) 249EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8) 250EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8) 251 ;; 252EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8) 253EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8) 254EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8) 255EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8) 256 ;; 257EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8) 258EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8) 259EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8) 260EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8) 261 br.ctop.sptk .line_copy 262 ;; 263 264 add dst0=-8,dst0 265 add src0=-8,src0 266 mov in2=tmp 267 .restore sp 268 br.sptk.many .medium_copy 269 ;; 270 271#define BLOCK_SIZE 128*32 272#define blocksize r23 273#define curlen r24 274 275// dest is on 8-byte boundary, src is not. We need to do 276// ld8-ld8, shrp, then st8. Max 8 byte copy per cycle. 277.unaligned_src: 278 .prologue 279 .save ar.pfs, saved_pfs 280 alloc saved_pfs=ar.pfs,3,5,0,8 281 .save ar.lc, saved_lc 282 mov saved_lc=ar.lc 283 .save pr, saved_pr 284 mov saved_pr=pr 285 .body 286.4k_block: 287 mov saved_in0=dst0 // need to save all input arguments 288 mov saved_in2=in2 289 mov blocksize=BLOCK_SIZE 290 ;; 291 cmp.lt p6,p7=blocksize,in2 292 mov saved_in1=src0 293 ;; 294(p6) mov in2=blocksize 295 ;; 296 shr.u r21=in2,7 // this much cache line 297 shr.u r22=in2,4 // number of 16-byte iteration 298 and curlen=15,in2 // copy length after iteration 299 and r30=7,src0 // source alignment 300 ;; 301 cmp.lt p7,p8=1,r21 302 add cnt=-1,r21 303 ;; 304 305 add src_pre_mem=0,src0 // prefetch src pointer 306 add dst_pre_mem=0,dst0 // prefetch dest pointer 307 and src0=-8,src0 // 1st src pointer 308(p7) mov ar.lc = cnt 309(p8) mov ar.lc = r0 310 ;; 311 TEXT_ALIGN(32) 3121: lfetch.fault [src_pre_mem], 128 313 lfetch.fault.excl [dst_pre_mem], 128 314 br.cloop.dptk.few 1b 315 ;; 316 317 shladd dst1=r22,3,dst0 // 2nd dest pointer 318 shladd src1=r22,3,src0 // 2nd src pointer 319 cmp.eq p8,p9=r22,r0 // do we really need to loop? 320 cmp.le p6,p7=8,curlen; // have at least 8 byte remaining? 321 add cnt=-1,r22 // ctop iteration adjustment 322 ;; 323EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer 324EK(.ex_handler, (p9) ld8 r37=[src1],8) 325(p8) br.dpnt.few .noloop 326 ;; 327 328// The jump address is calculated based on src alignment. The COPYU 329// macro below need to confine its size to power of two, so an entry 330// can be caulated using shl instead of an expensive multiply. The 331// size is then hard coded by the following #define to match the 332// actual size. This make it somewhat tedious when COPYU macro gets 333// changed and this need to be adjusted to match. 334#define LOOP_SIZE 6 3351: 336 mov r29=ip // jmp_table thread 337 mov ar.lc=cnt 338 ;; 339 add r29=.jump_table - 1b - (.jmp1-.jump_table), r29 340 shl r28=r30, LOOP_SIZE // jmp_table thread 341 mov ar.ec=2 // loop setup 342 ;; 343 add r29=r29,r28 // jmp_table thread 344 cmp.eq p16,p17=r0,r0 345 ;; 346 mov b6=r29 // jmp_table thread 347 ;; 348 br.cond.sptk.few b6 349 350// for 8-15 byte case 351// We will skip the loop, but need to replicate the side effect 352// that the loop produces. 353.noloop: 354EX(.ex_handler, (p6) ld8 r37=[src1],8) 355 add src0=8,src0 356(p6) shl r25=r30,3 357 ;; 358EX(.ex_handler, (p6) ld8 r27=[src1]) 359(p6) shr.u r28=r37,r25 360(p6) sub r26=64,r25 361 ;; 362(p6) shl r27=r27,r26 363 ;; 364(p6) or r21=r28,r27 365 366.unaligned_src_tail: 367/* check if we have more than blocksize to copy, if so go back */ 368 cmp.gt p8,p0=saved_in2,blocksize 369 ;; 370(p8) add dst0=saved_in0,blocksize 371(p8) add src0=saved_in1,blocksize 372(p8) sub in2=saved_in2,blocksize 373(p8) br.dpnt .4k_block 374 ;; 375 376/* we have up to 15 byte to copy in the tail. 377 * part of work is already done in the jump table code 378 * we are at the following state. 379 * src side: 380 * 381 * xxxxxx xx <----- r21 has xxxxxxxx already 382 * -------- -------- -------- 383 * 0 8 16 384 * ^ 385 * | 386 * src1 387 * 388 * dst 389 * -------- -------- -------- 390 * ^ 391 * | 392 * dst1 393 */ 394EX(.ex_handler, (p6) st8 [dst1]=r21,8) // more than 8 byte to copy 395(p6) add curlen=-8,curlen // update length 396 mov ar.pfs=saved_pfs 397 ;; 398 mov ar.lc=saved_lc 399 mov pr=saved_pr,-1 400 mov in2=curlen // remaining length 401 mov dst0=dst1 // dest pointer 402 add src0=src1,r30 // forward by src alignment 403 ;; 404 405// 7 byte or smaller. 406.memcpy_short: 407 cmp.le p8,p9 = 1,in2 408 cmp.le p10,p11 = 2,in2 409 cmp.le p12,p13 = 3,in2 410 cmp.le p14,p15 = 4,in2 411 add src1=1,src0 // second src pointer 412 add dst1=1,dst0 // second dest pointer 413 ;; 414 415EX(.ex_handler_short, (p8) ld1 t1=[src0],2) 416EK(.ex_handler_short, (p10) ld1 t2=[src1],2) 417(p9) br.ret.dpnt rp // 0 byte copy 418 ;; 419 420EX(.ex_handler_short, (p8) st1 [dst0]=t1,2) 421EK(.ex_handler_short, (p10) st1 [dst1]=t2,2) 422(p11) br.ret.dpnt rp // 1 byte copy 423 424EX(.ex_handler_short, (p12) ld1 t3=[src0],2) 425EK(.ex_handler_short, (p14) ld1 t4=[src1],2) 426(p13) br.ret.dpnt rp // 2 byte copy 427 ;; 428 429 cmp.le p6,p7 = 5,in2 430 cmp.le p8,p9 = 6,in2 431 cmp.le p10,p11 = 7,in2 432 433EX(.ex_handler_short, (p12) st1 [dst0]=t3,2) 434EK(.ex_handler_short, (p14) st1 [dst1]=t4,2) 435(p15) br.ret.dpnt rp // 3 byte copy 436 ;; 437 438EX(.ex_handler_short, (p6) ld1 t5=[src0],2) 439EK(.ex_handler_short, (p8) ld1 t6=[src1],2) 440(p7) br.ret.dpnt rp // 4 byte copy 441 ;; 442 443EX(.ex_handler_short, (p6) st1 [dst0]=t5,2) 444EK(.ex_handler_short, (p8) st1 [dst1]=t6,2) 445(p9) br.ret.dptk rp // 5 byte copy 446 447EX(.ex_handler_short, (p10) ld1 t7=[src0],2) 448(p11) br.ret.dptk rp // 6 byte copy 449 ;; 450 451EX(.ex_handler_short, (p10) st1 [dst0]=t7,2) 452 br.ret.dptk rp // done all cases 453 454 455/* Align dest to nearest 8-byte boundary. We know we have at 456 * least 7 bytes to copy, enough to crawl to 8-byte boundary. 457 * Actual number of byte to crawl depend on the dest alignment. 458 * 7 byte or less is taken care at .memcpy_short 459 460 * src0 - source even index 461 * src1 - source odd index 462 * dst0 - dest even index 463 * dst1 - dest odd index 464 * r30 - distance to 8-byte boundary 465 */ 466 467.align_dest: 468 add src1=1,in1 // source odd index 469 cmp.le p7,p0 = 2,r30 // for .align_dest 470 cmp.le p8,p0 = 3,r30 // for .align_dest 471EX(.ex_handler_short, (p6) ld1 t1=[src0],2) 472 cmp.le p9,p0 = 4,r30 // for .align_dest 473 cmp.le p10,p0 = 5,r30 474 ;; 475EX(.ex_handler_short, (p7) ld1 t2=[src1],2) 476EK(.ex_handler_short, (p8) ld1 t3=[src0],2) 477 cmp.le p11,p0 = 6,r30 478EX(.ex_handler_short, (p6) st1 [dst0] = t1,2) 479 cmp.le p12,p0 = 7,r30 480 ;; 481EX(.ex_handler_short, (p9) ld1 t4=[src1],2) 482EK(.ex_handler_short, (p10) ld1 t5=[src0],2) 483EX(.ex_handler_short, (p7) st1 [dst1] = t2,2) 484EK(.ex_handler_short, (p8) st1 [dst0] = t3,2) 485 ;; 486EX(.ex_handler_short, (p11) ld1 t6=[src1],2) 487EK(.ex_handler_short, (p12) ld1 t7=[src0],2) 488 cmp.eq p6,p7=r28,r29 489EX(.ex_handler_short, (p9) st1 [dst1] = t4,2) 490EK(.ex_handler_short, (p10) st1 [dst0] = t5,2) 491 sub in2=in2,r30 492 ;; 493EX(.ex_handler_short, (p11) st1 [dst1] = t6,2) 494EK(.ex_handler_short, (p12) st1 [dst0] = t7) 495 add dst0=in0,r30 // setup arguments 496 add src0=in1,r30 497(p6) br.cond.dptk .aligned_src 498(p7) br.cond.dpnt .unaligned_src 499 ;; 500 501/* main loop body in jump table format */ 502#define COPYU(shift) \ 5031: \ 504EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \ 505EK(.ex_handler, (p16) ld8 r36=[src1],8); \ 506 (p17) shrp r35=r33,r34,shift;; /* 1 */ \ 507EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \ 508 nop.m 0; \ 509 (p16) shrp r38=r36,r37,shift; \ 510EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \ 511EK(.ex_handler, (p17) st8 [dst1]=r39,8); \ 512 br.ctop.dptk.few 1b;; \ 513 (p7) add src1=-8,src1; /* back out for <8 byte case */ \ 514 shrp r21=r22,r38,shift; /* speculative work */ \ 515 br.sptk.few .unaligned_src_tail /* branch out of jump table */ \ 516 ;; 517 TEXT_ALIGN(32) 518.jump_table: 519 COPYU(8) // unaligned cases 520.jmp1: 521 COPYU(16) 522 COPYU(24) 523 COPYU(32) 524 COPYU(40) 525 COPYU(48) 526 COPYU(56) 527 528#undef A 529#undef B 530#undef C 531#undef D 532 533/* 534 * Due to lack of local tag support in gcc 2.x assembler, it is not clear which 535 * instruction failed in the bundle. The exception algorithm is that we 536 * first figure out the faulting address, then detect if there is any 537 * progress made on the copy, if so, redo the copy from last known copied 538 * location up to the faulting address (exclusive). In the copy_from_user 539 * case, remaining byte in kernel buffer will be zeroed. 540 * 541 * Take copy_from_user as an example, in the code there are multiple loads 542 * in a bundle and those multiple loads could span over two pages, the 543 * faulting address is calculated as page_round_down(max(src0, src1)). 544 * This is based on knowledge that if we can access one byte in a page, we 545 * can access any byte in that page. 546 * 547 * predicate used in the exception handler: 548 * p6-p7: direction 549 * p10-p11: src faulting addr calculation 550 * p12-p13: dst faulting addr calculation 551 */ 552 553#define A r19 554#define B r20 555#define C r21 556#define D r22 557#define F r28 558 559#define saved_retval loc0 560#define saved_rtlink loc1 561#define saved_pfs_stack loc2 562 563.ex_hndlr_s: 564 add src0=8,src0 565 br.sptk .ex_handler 566 ;; 567.ex_hndlr_d: 568 add dst0=8,dst0 569 br.sptk .ex_handler 570 ;; 571.ex_hndlr_lcpy_1: 572 mov src1=src_pre_mem 573 mov dst1=dst_pre_mem 574 cmp.gtu p10,p11=src_pre_mem,saved_in1 575 cmp.gtu p12,p13=dst_pre_mem,saved_in0 576 ;; 577(p10) add src0=8,saved_in1 578(p11) mov src0=saved_in1 579(p12) add dst0=8,saved_in0 580(p13) mov dst0=saved_in0 581 br.sptk .ex_handler 582.ex_handler_lcpy: 583 // in line_copy block, the preload addresses should always ahead 584 // of the other two src/dst pointers. Furthermore, src1/dst1 should 585 // always ahead of src0/dst0. 586 mov src1=src_pre_mem 587 mov dst1=dst_pre_mem 588.ex_handler: 589 mov pr=saved_pr,-1 // first restore pr, lc, and pfs 590 mov ar.lc=saved_lc 591 mov ar.pfs=saved_pfs 592 ;; 593.ex_handler_short: // fault occurred in these sections didn't change pr, lc, pfs 594 cmp.ltu p6,p7=saved_in0, saved_in1 // get the copy direction 595 cmp.ltu p10,p11=src0,src1 596 cmp.ltu p12,p13=dst0,dst1 597 fcmp.eq p8,p0=f6,f0 // is it memcpy? 598 mov tmp = dst0 599 ;; 600(p11) mov src1 = src0 // pick the larger of the two 601(p13) mov dst0 = dst1 // make dst0 the smaller one 602(p13) mov dst1 = tmp // and dst1 the larger one 603 ;; 604(p6) dep F = r0,dst1,0,PAGE_SHIFT // usr dst round down to page boundary 605(p7) dep F = r0,src1,0,PAGE_SHIFT // usr src round down to page boundary 606 ;; 607(p6) cmp.le p14,p0=dst0,saved_in0 // no progress has been made on store 608(p7) cmp.le p14,p0=src0,saved_in1 // no progress has been made on load 609 mov retval=saved_in2 610(p8) ld1 tmp=[src1] // force an oops for memcpy call 611(p8) st1 [dst1]=r0 // force an oops for memcpy call 612(p14) br.ret.sptk.many rp 613 614/* 615 * The remaining byte to copy is calculated as: 616 * 617 * A = (faulting_addr - orig_src) -> len to faulting ld address 618 * or 619 * (faulting_addr - orig_dst) -> len to faulting st address 620 * B = (cur_dst - orig_dst) -> len copied so far 621 * C = A - B -> len need to be copied 622 * D = orig_len - A -> len need to be left along 623 */ 624(p6) sub A = F, saved_in0 625(p7) sub A = F, saved_in1 626 clrrrb 627 ;; 628 alloc saved_pfs_stack=ar.pfs,3,3,3,0 629 cmp.lt p8,p0=A,r0 630 sub B = dst0, saved_in0 // how many byte copied so far 631 ;; 632(p8) mov A = 0; // A shouldn't be negative, cap it 633 ;; 634 sub C = A, B 635 sub D = saved_in2, A 636 ;; 637 cmp.gt p8,p0=C,r0 // more than 1 byte? 638 mov r8=0 639 mov saved_retval = D 640 mov saved_rtlink = b0 641 642 add out0=saved_in0, B 643 add out1=saved_in1, B 644 mov out2=C 645(p8) br.call.sptk.few b0=__copy_user // recursive call 646 ;; 647 648 add saved_retval=saved_retval,r8 // above might return non-zero value 649 ;; 650 651 mov retval=saved_retval 652 mov ar.pfs=saved_pfs_stack 653 mov b0=saved_rtlink 654 br.ret.sptk.many rp 655 656/* end of McKinley specific optimization */ 657END(__copy_user) 658EXPORT_SYMBOL(__copy_user) 659