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 75 GLOBAL_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 ;; 82 END(memcpy) 83 EXPORT_SYMBOL(memcpy) 84 GLOBAL_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) 156 1: 157 EX(.ex_handler, (p16) ld8 r34=[src0],16) 158 EK(.ex_handler, (p16) ld8 r38=[src1],16) 159 EX(.ex_handler, (p17) st8 [dst0]=r33,16) 160 EK(.ex_handler, (p17) st8 [dst1]=r37,16) 161 ;; 162 EX(.ex_handler, (p16) ld8 r32=[src0],16) 163 EK(.ex_handler, (p16) ld8 r36=[src1],16) 164 EX(.ex_handler, (p16) st8 [dst0]=r34,16) 165 EK(.ex_handler, (p16) st8 [dst1]=r38,16) 166 br.ctop.dptk.few 1b 167 ;; 168 169 .aligned_src_tail: 170 EX(.ex_handler, (p6) ld8 t1=[src0]) 171 mov ar.lc=saved_lc 172 mov ar.pfs=saved_pfs 173 EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8) 174 cmp.le p8,p0=24,tmp 175 and r21=-8,tmp 176 ;; 177 EX(.ex_hndlr_s, (p8) ld8 t3=[src1]) 178 EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1 179 and in2=7,tmp // remaining length 180 EX(.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 ;; 184 EX(.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: 214 EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 215 EK(.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: 223 EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0 224 EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1 225 EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory 226 EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2 227 ;; 228 EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory 229 EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2 230 EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2 231 EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3 232 ;; 233 EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8) 234 EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8) 235 EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8) 236 EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8) 237 ;; 238 EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8) 239 EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8) 240 EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8) 241 EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8) 242 ;; 243 EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8) 244 EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8) 245 EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8) 246 EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8) 247 ;; 248 EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8) 249 EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8) 250 EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8) 251 EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8) 252 ;; 253 EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8) 254 EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8) 255 EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8) 256 EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8) 257 ;; 258 EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8) 259 EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8) 260 EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8) 261 EK(.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) 313 1: 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 ;; 324 EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer 325 EK(.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 6 336 1: 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: 355 EX(.ex_handler, (p6) ld8 r37=[src1],8) 356 add src0=8,src0 357 (p6) shl r25=r30,3 358 ;; 359 EX(.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 */ 395 EX(.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 ;; 415 416 EX(.ex_handler_short, (p8) ld1 t1=[src0],2) 417 EK(.ex_handler_short, (p10) ld1 t2=[src1],2) 418 (p9) br.ret.dpnt rp // 0 byte copy 419 ;; 420 421 EX(.ex_handler_short, (p8) st1 [dst0]=t1,2) 422 EK(.ex_handler_short, (p10) st1 [dst1]=t2,2) 423 (p11) br.ret.dpnt rp // 1 byte copy 424 425 EX(.ex_handler_short, (p12) ld1 t3=[src0],2) 426 EK(.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 433 434 EX(.ex_handler_short, (p12) st1 [dst0]=t3,2) 435 EK(.ex_handler_short, (p14) st1 [dst1]=t4,2) 436 (p15) br.ret.dpnt rp // 3 byte copy 437 ;; 438 439 EX(.ex_handler_short, (p6) ld1 t5=[src0],2) 440 EK(.ex_handler_short, (p8) ld1 t6=[src1],2) 441 (p7) br.ret.dpnt rp // 4 byte copy 442 ;; 443 444 EX(.ex_handler_short, (p6) st1 [dst0]=t5,2) 445 EK(.ex_handler_short, (p8) st1 [dst1]=t6,2) 446 (p9) br.ret.dptk rp // 5 byte copy 447 448 EX(.ex_handler_short, (p10) ld1 t7=[src0],2) 449 (p11) br.ret.dptk rp // 6 byte copy 450 ;; 451 452 EX(.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 472 EX(.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 ;; 476 EX(.ex_handler_short, (p7) ld1 t2=[src1],2) 477 EK(.ex_handler_short, (p8) ld1 t3=[src0],2) 478 cmp.le p11,p0 = 6,r30 479 EX(.ex_handler_short, (p6) st1 [dst0] = t1,2) 480 cmp.le p12,p0 = 7,r30 481 ;; 482 EX(.ex_handler_short, (p9) ld1 t4=[src1],2) 483 EK(.ex_handler_short, (p10) ld1 t5=[src0],2) 484 EX(.ex_handler_short, (p7) st1 [dst1] = t2,2) 485 EK(.ex_handler_short, (p8) st1 [dst0] = t3,2) 486 ;; 487 EX(.ex_handler_short, (p11) ld1 t6=[src1],2) 488 EK(.ex_handler_short, (p12) ld1 t7=[src0],2) 489 cmp.eq p6,p7=r28,r29 490 EX(.ex_handler_short, (p9) st1 [dst1] = t4,2) 491 EK(.ex_handler_short, (p10) st1 [dst0] = t5,2) 492 sub in2=in2,r30 493 ;; 494 EX(.ex_handler_short, (p11) st1 [dst1] = t6,2) 495 EK(.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) \ 504 1: \ 505 EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \ 506 EK(.ex_handler, (p16) ld8 r36=[src1],8); \ 507 (p17) shrp r35=r33,r34,shift;; /* 1 */ \ 508 EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \ 509 nop.m 0; \ 510 (p16) shrp r38=r36,r37,shift; \ 511 EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \ 512 EK(.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 */ 658 END(__copy_user) 659 EXPORT_SYMBOL(__copy_user) 660