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 ;; 78END(memcpy) 79GLOBAL_ENTRY(__copy_user) 80 .prologue 81// check dest alignment 82 and r28=0x7,in0 83 and r29=0x7,in1 84 mov f6=f1 85 mov saved_in0=in0 // save dest pointer 86 mov saved_in1=in1 // save src pointer 87 mov saved_in2=in2 // save len 88 ;; 89.common_code: 90 cmp.gt p15,p0=8,in2 // check for small size 91 cmp.ne p13,p0=0,r28 // check dest alignment 92 cmp.ne p14,p0=0,r29 // check src alignment 93 add src0=0,in1 94 sub r30=8,r28 // for .align_dest 95 mov retval=r0 // initialize return value 96 ;; 97 add dst0=0,in0 98 add dst1=1,in0 // dest odd index 99 cmp.le p6,p0 = 1,r30 // for .align_dest 100(p15) br.cond.dpnt .memcpy_short 101(p13) br.cond.dpnt .align_dest 102(p14) br.cond.dpnt .unaligned_src 103 ;; 104 105// both dest and src are aligned on 8-byte boundary 106.aligned_src: 107 .save ar.pfs, saved_pfs 108 alloc saved_pfs=ar.pfs,3,Nrot-3,0,Nrot 109 .save pr, saved_pr 110 mov saved_pr=pr 111 112 shr.u cnt=in2,7 // this much cache line 113 ;; 114 cmp.lt p6,p0=2*PREFETCH_DIST,cnt 115 cmp.lt p7,p8=1,cnt 116 .save ar.lc, saved_lc 117 mov saved_lc=ar.lc 118 .body 119 add cnt=-1,cnt 120 add src_pre_mem=0,in1 // prefetch src pointer 121 add dst_pre_mem=0,in0 // prefetch dest pointer 122 ;; 123(p7) mov ar.lc=cnt // prefetch count 124(p8) mov ar.lc=r0 125(p6) br.cond.dpnt .long_copy 126 ;; 127 128.prefetch: 129 lfetch.fault [src_pre_mem], 128 130 lfetch.fault.excl [dst_pre_mem], 128 131 br.cloop.dptk.few .prefetch 132 ;; 133 134.medium_copy: 135 and tmp=31,in2 // copy length after iteration 136 shr.u r29=in2,5 // number of 32-byte iteration 137 add dst1=8,dst0 // 2nd dest pointer 138 ;; 139 add cnt=-1,r29 // ctop iteration adjustment 140 cmp.eq p10,p0=r29,r0 // do we really need to loop? 141 add src1=8,src0 // 2nd src pointer 142 cmp.le p6,p0=8,tmp 143 ;; 144 cmp.le p7,p0=16,tmp 145 mov ar.lc=cnt // loop setup 146 cmp.eq p16,p17 = r0,r0 147 mov ar.ec=2 148(p10) br.dpnt.few .aligned_src_tail 149 ;; 150 TEXT_ALIGN(32) 1511: 152EX(.ex_handler, (p16) ld8 r34=[src0],16) 153EK(.ex_handler, (p16) ld8 r38=[src1],16) 154EX(.ex_handler, (p17) st8 [dst0]=r33,16) 155EK(.ex_handler, (p17) st8 [dst1]=r37,16) 156 ;; 157EX(.ex_handler, (p16) ld8 r32=[src0],16) 158EK(.ex_handler, (p16) ld8 r36=[src1],16) 159EX(.ex_handler, (p16) st8 [dst0]=r34,16) 160EK(.ex_handler, (p16) st8 [dst1]=r38,16) 161 br.ctop.dptk.few 1b 162 ;; 163 164.aligned_src_tail: 165EX(.ex_handler, (p6) ld8 t1=[src0]) 166 mov ar.lc=saved_lc 167 mov ar.pfs=saved_pfs 168EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8) 169 cmp.le p8,p0=24,tmp 170 and r21=-8,tmp 171 ;; 172EX(.ex_hndlr_s, (p8) ld8 t3=[src1]) 173EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1 174 and in2=7,tmp // remaining length 175EX(.ex_hndlr_d, (p7) st8 [dst1]=t2,8) // store byte 2 176 add src0=src0,r21 // setting up src pointer 177 add dst0=dst0,r21 // setting up dest pointer 178 ;; 179EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3 180 mov pr=saved_pr,-1 181 br.dptk.many .memcpy_short 182 ;; 183 184/* code taken from copy_page_mck */ 185.long_copy: 186 .rotr v[2*PREFETCH_DIST] 187 .rotp p[N] 188 189 mov src_pre_mem = src0 190 mov pr.rot = 0x10000 191 mov ar.ec = 1 // special unrolled loop 192 193 mov dst_pre_mem = dst0 194 195 add src_pre_l2 = 8*8, src0 196 add dst_pre_l2 = 8*8, dst0 197 ;; 198 add src0 = 8, src_pre_mem // first t1 src 199 mov ar.lc = 2*PREFETCH_DIST - 1 200 shr.u cnt=in2,7 // number of lines 201 add src1 = 3*8, src_pre_mem // first t3 src 202 add dst0 = 8, dst_pre_mem // first t1 dst 203 add dst1 = 3*8, dst_pre_mem // first t3 dst 204 ;; 205 and tmp=127,in2 // remaining bytes after this block 206 add cnt = -(2*PREFETCH_DIST) - 1, cnt 207 // same as .line_copy loop, but with all predicated-off instructions removed: 208.prefetch_loop: 209EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 210EK(.ex_hndlr_lcpy_1, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 211 br.ctop.sptk .prefetch_loop 212 ;; 213 cmp.eq p16, p0 = r0, r0 // reset p16 to 1 214 mov ar.lc = cnt 215 mov ar.ec = N // # of stages in pipeline 216 ;; 217.line_copy: 218EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0 219EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1 220EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory 221EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2 222 ;; 223EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory 224EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2 225EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2 226EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3 227 ;; 228EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8) 229EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8) 230EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8) 231EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8) 232 ;; 233EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8) 234EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8) 235EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8) 236EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8) 237 ;; 238EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8) 239EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8) 240EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8) 241EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8) 242 ;; 243EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8) 244EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8) 245EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8) 246EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8) 247 ;; 248EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8) 249EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8) 250EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8) 251EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8) 252 ;; 253EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8) 254EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8) 255EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8) 256EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8) 257 br.ctop.sptk .line_copy 258 ;; 259 260 add dst0=-8,dst0 261 add src0=-8,src0 262 mov in2=tmp 263 .restore sp 264 br.sptk.many .medium_copy 265 ;; 266 267#define BLOCK_SIZE 128*32 268#define blocksize r23 269#define curlen r24 270 271// dest is on 8-byte boundary, src is not. We need to do 272// ld8-ld8, shrp, then st8. Max 8 byte copy per cycle. 273.unaligned_src: 274 .prologue 275 .save ar.pfs, saved_pfs 276 alloc saved_pfs=ar.pfs,3,5,0,8 277 .save ar.lc, saved_lc 278 mov saved_lc=ar.lc 279 .save pr, saved_pr 280 mov saved_pr=pr 281 .body 282.4k_block: 283 mov saved_in0=dst0 // need to save all input arguments 284 mov saved_in2=in2 285 mov blocksize=BLOCK_SIZE 286 ;; 287 cmp.lt p6,p7=blocksize,in2 288 mov saved_in1=src0 289 ;; 290(p6) mov in2=blocksize 291 ;; 292 shr.u r21=in2,7 // this much cache line 293 shr.u r22=in2,4 // number of 16-byte iteration 294 and curlen=15,in2 // copy length after iteration 295 and r30=7,src0 // source alignment 296 ;; 297 cmp.lt p7,p8=1,r21 298 add cnt=-1,r21 299 ;; 300 301 add src_pre_mem=0,src0 // prefetch src pointer 302 add dst_pre_mem=0,dst0 // prefetch dest pointer 303 and src0=-8,src0 // 1st src pointer 304(p7) mov ar.lc = cnt 305(p8) mov ar.lc = r0 306 ;; 307 TEXT_ALIGN(32) 3081: lfetch.fault [src_pre_mem], 128 309 lfetch.fault.excl [dst_pre_mem], 128 310 br.cloop.dptk.few 1b 311 ;; 312 313 shladd dst1=r22,3,dst0 // 2nd dest pointer 314 shladd src1=r22,3,src0 // 2nd src pointer 315 cmp.eq p8,p9=r22,r0 // do we really need to loop? 316 cmp.le p6,p7=8,curlen; // have at least 8 byte remaining? 317 add cnt=-1,r22 // ctop iteration adjustment 318 ;; 319EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer 320EK(.ex_handler, (p9) ld8 r37=[src1],8) 321(p8) br.dpnt.few .noloop 322 ;; 323 324// The jump address is calculated based on src alignment. The COPYU 325// macro below need to confine its size to power of two, so an entry 326// can be caulated using shl instead of an expensive multiply. The 327// size is then hard coded by the following #define to match the 328// actual size. This make it somewhat tedious when COPYU macro gets 329// changed and this need to be adjusted to match. 330#define LOOP_SIZE 6 3311: 332 mov r29=ip // jmp_table thread 333 mov ar.lc=cnt 334 ;; 335 add r29=.jump_table - 1b - (.jmp1-.jump_table), r29 336 shl r28=r30, LOOP_SIZE // jmp_table thread 337 mov ar.ec=2 // loop setup 338 ;; 339 add r29=r29,r28 // jmp_table thread 340 cmp.eq p16,p17=r0,r0 341 ;; 342 mov b6=r29 // jmp_table thread 343 ;; 344 br.cond.sptk.few b6 345 346// for 8-15 byte case 347// We will skip the loop, but need to replicate the side effect 348// that the loop produces. 349.noloop: 350EX(.ex_handler, (p6) ld8 r37=[src1],8) 351 add src0=8,src0 352(p6) shl r25=r30,3 353 ;; 354EX(.ex_handler, (p6) ld8 r27=[src1]) 355(p6) shr.u r28=r37,r25 356(p6) sub r26=64,r25 357 ;; 358(p6) shl r27=r27,r26 359 ;; 360(p6) or r21=r28,r27 361 362.unaligned_src_tail: 363/* check if we have more than blocksize to copy, if so go back */ 364 cmp.gt p8,p0=saved_in2,blocksize 365 ;; 366(p8) add dst0=saved_in0,blocksize 367(p8) add src0=saved_in1,blocksize 368(p8) sub in2=saved_in2,blocksize 369(p8) br.dpnt .4k_block 370 ;; 371 372/* we have up to 15 byte to copy in the tail. 373 * part of work is already done in the jump table code 374 * we are at the following state. 375 * src side: 376 * 377 * xxxxxx xx <----- r21 has xxxxxxxx already 378 * -------- -------- -------- 379 * 0 8 16 380 * ^ 381 * | 382 * src1 383 * 384 * dst 385 * -------- -------- -------- 386 * ^ 387 * | 388 * dst1 389 */ 390EX(.ex_handler, (p6) st8 [dst1]=r21,8) // more than 8 byte to copy 391(p6) add curlen=-8,curlen // update length 392 mov ar.pfs=saved_pfs 393 ;; 394 mov ar.lc=saved_lc 395 mov pr=saved_pr,-1 396 mov in2=curlen // remaining length 397 mov dst0=dst1 // dest pointer 398 add src0=src1,r30 // forward by src alignment 399 ;; 400 401// 7 byte or smaller. 402.memcpy_short: 403 cmp.le p8,p9 = 1,in2 404 cmp.le p10,p11 = 2,in2 405 cmp.le p12,p13 = 3,in2 406 cmp.le p14,p15 = 4,in2 407 add src1=1,src0 // second src pointer 408 add dst1=1,dst0 // second dest pointer 409 ;; 410 411EX(.ex_handler_short, (p8) ld1 t1=[src0],2) 412EK(.ex_handler_short, (p10) ld1 t2=[src1],2) 413(p9) br.ret.dpnt rp // 0 byte copy 414 ;; 415 416EX(.ex_handler_short, (p8) st1 [dst0]=t1,2) 417EK(.ex_handler_short, (p10) st1 [dst1]=t2,2) 418(p11) br.ret.dpnt rp // 1 byte copy 419 420EX(.ex_handler_short, (p12) ld1 t3=[src0],2) 421EK(.ex_handler_short, (p14) ld1 t4=[src1],2) 422(p13) br.ret.dpnt rp // 2 byte copy 423 ;; 424 425 cmp.le p6,p7 = 5,in2 426 cmp.le p8,p9 = 6,in2 427 cmp.le p10,p11 = 7,in2 428 429EX(.ex_handler_short, (p12) st1 [dst0]=t3,2) 430EK(.ex_handler_short, (p14) st1 [dst1]=t4,2) 431(p15) br.ret.dpnt rp // 3 byte copy 432 ;; 433 434EX(.ex_handler_short, (p6) ld1 t5=[src0],2) 435EK(.ex_handler_short, (p8) ld1 t6=[src1],2) 436(p7) br.ret.dpnt rp // 4 byte copy 437 ;; 438 439EX(.ex_handler_short, (p6) st1 [dst0]=t5,2) 440EK(.ex_handler_short, (p8) st1 [dst1]=t6,2) 441(p9) br.ret.dptk rp // 5 byte copy 442 443EX(.ex_handler_short, (p10) ld1 t7=[src0],2) 444(p11) br.ret.dptk rp // 6 byte copy 445 ;; 446 447EX(.ex_handler_short, (p10) st1 [dst0]=t7,2) 448 br.ret.dptk rp // done all cases 449 450 451/* Align dest to nearest 8-byte boundary. We know we have at 452 * least 7 bytes to copy, enough to crawl to 8-byte boundary. 453 * Actual number of byte to crawl depend on the dest alignment. 454 * 7 byte or less is taken care at .memcpy_short 455 456 * src0 - source even index 457 * src1 - source odd index 458 * dst0 - dest even index 459 * dst1 - dest odd index 460 * r30 - distance to 8-byte boundary 461 */ 462 463.align_dest: 464 add src1=1,in1 // source odd index 465 cmp.le p7,p0 = 2,r30 // for .align_dest 466 cmp.le p8,p0 = 3,r30 // for .align_dest 467EX(.ex_handler_short, (p6) ld1 t1=[src0],2) 468 cmp.le p9,p0 = 4,r30 // for .align_dest 469 cmp.le p10,p0 = 5,r30 470 ;; 471EX(.ex_handler_short, (p7) ld1 t2=[src1],2) 472EK(.ex_handler_short, (p8) ld1 t3=[src0],2) 473 cmp.le p11,p0 = 6,r30 474EX(.ex_handler_short, (p6) st1 [dst0] = t1,2) 475 cmp.le p12,p0 = 7,r30 476 ;; 477EX(.ex_handler_short, (p9) ld1 t4=[src1],2) 478EK(.ex_handler_short, (p10) ld1 t5=[src0],2) 479EX(.ex_handler_short, (p7) st1 [dst1] = t2,2) 480EK(.ex_handler_short, (p8) st1 [dst0] = t3,2) 481 ;; 482EX(.ex_handler_short, (p11) ld1 t6=[src1],2) 483EK(.ex_handler_short, (p12) ld1 t7=[src0],2) 484 cmp.eq p6,p7=r28,r29 485EX(.ex_handler_short, (p9) st1 [dst1] = t4,2) 486EK(.ex_handler_short, (p10) st1 [dst0] = t5,2) 487 sub in2=in2,r30 488 ;; 489EX(.ex_handler_short, (p11) st1 [dst1] = t6,2) 490EK(.ex_handler_short, (p12) st1 [dst0] = t7) 491 add dst0=in0,r30 // setup arguments 492 add src0=in1,r30 493(p6) br.cond.dptk .aligned_src 494(p7) br.cond.dpnt .unaligned_src 495 ;; 496 497/* main loop body in jump table format */ 498#define COPYU(shift) \ 4991: \ 500EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \ 501EK(.ex_handler, (p16) ld8 r36=[src1],8); \ 502 (p17) shrp r35=r33,r34,shift;; /* 1 */ \ 503EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \ 504 nop.m 0; \ 505 (p16) shrp r38=r36,r37,shift; \ 506EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \ 507EK(.ex_handler, (p17) st8 [dst1]=r39,8); \ 508 br.ctop.dptk.few 1b;; \ 509 (p7) add src1=-8,src1; /* back out for <8 byte case */ \ 510 shrp r21=r22,r38,shift; /* speculative work */ \ 511 br.sptk.few .unaligned_src_tail /* branch out of jump table */ \ 512 ;; 513 TEXT_ALIGN(32) 514.jump_table: 515 COPYU(8) // unaligned cases 516.jmp1: 517 COPYU(16) 518 COPYU(24) 519 COPYU(32) 520 COPYU(40) 521 COPYU(48) 522 COPYU(56) 523 524#undef A 525#undef B 526#undef C 527#undef D 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 cmp.lt p8,p0=A,r0 629 sub B = dst0, saved_in0 // how many byte copied so far 630 ;; 631(p8) mov A = 0; // A shouldn't be negative, cap it 632 ;; 633 sub C = A, B 634 sub D = saved_in2, A 635 ;; 636 cmp.gt p8,p0=C,r0 // more than 1 byte? 637 add memset_arg0=saved_in0, A 638(p6) mov memset_arg2=0 // copy_to_user should not call memset 639(p7) mov memset_arg2=D // copy_from_user need to have kbuf zeroed 640 mov r8=0 641 mov saved_retval = D 642 mov saved_rtlink = b0 643 644 add out0=saved_in0, B 645 add out1=saved_in1, B 646 mov out2=C 647(p8) br.call.sptk.few b0=__copy_user // recursive call 648 ;; 649 650 add saved_retval=saved_retval,r8 // above might return non-zero value 651 cmp.gt p8,p0=memset_arg2,r0 // more than 1 byte? 652 mov out0=memset_arg0 // *s 653 mov out1=r0 // c 654 mov out2=memset_arg2 // n 655(p8) br.call.sptk.few b0=memset 656 ;; 657 658 mov retval=saved_retval 659 mov ar.pfs=saved_pfs_stack 660 mov b0=saved_rtlink 661 br.ret.sptk.many rp 662 663/* end of McKinley specific optimization */ 664END(__copy_user) 665