1/*- 2 * Copyright (c) 1993 The Regents of the University of California. 3 * Copyright (c) 2003 Peter Wemm. 4 * Copyright (c) 2008 The DragonFly Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * $FreeBSD: src/sys/amd64/amd64/support.S,v 1.127 2007/05/23 08:33:04 kib Exp $ 32 */ 33 34#include <machine/asmacros.h> 35#include <machine/pmap.h> 36 37#include "assym.s" 38 39 ALIGN_DATA 40 41 .text 42 43/* 44 * bzero(ptr:%rdi, bytes:%rsi) 45 * 46 * Using rep stosq is 70% faster than a %rax loop and almost as fast as 47 * a %xmm0 loop on a modern intel cpu. 48 * 49 * Do not use non-termportal instructions here as we do not know the caller's 50 * intent. 51 */ 52ENTRY(bzero) 53 movq %rsi,%rcx 54 xorl %eax,%eax 55 shrq $3,%rcx 56 cld 57 rep 58 stosq 59 movq %rsi,%rcx 60 andq $7,%rcx 61 rep 62 stosb 63 ret 64END(bzero) 65 66/* 67 * pagezero(ptr:%rdi) 68 * 69 * Using rep stosq is nearly as fast as using %xmm0 on a modern intel cpu, 70 * and about 70% faster than a %rax loop. 71 * 72 * Do not use non-termportal instructions here as we do not know the caller's 73 * intent. 74 */ 75ENTRY(pagezero) 76 movq $PAGE_SIZE>>3,%rcx 77 xorl %eax,%eax 78 cld 79 rep 80 stosq 81 ret 82END(pagezero) 83 84/* 85 * bcmp(ptr:%rdi, ptr:%rsi, bytes:%rdx) 86 */ 87ENTRY(bcmp) 88 movq %rdx,%rcx 89 shrq $3,%rcx 90 cld /* compare forwards */ 91 repe 92 cmpsq 93 jne 1f 94 95 movq %rdx,%rcx 96 andq $7,%rcx 97 repe 98 cmpsb 991: 100 setne %al 101 movsbl %al,%eax 102 ret 103END(bcmp) 104 105/* 106 * bcopy(src:%rdi, dst:%rsi, cnt:%rdx) 107 * 108 * ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800 109 */ 110ENTRY(bcopy) 111 xchgq %rsi,%rdi 112 movq %rdx,%rcx 113 114 movq %rdi,%rax 115 subq %rsi,%rax 116 cmpq %rcx,%rax /* overlapping && src < dst? */ 117 jb 1f 118 119 shrq $3,%rcx /* copy by 64-bit words */ 120 cld /* nope, copy forwards */ 121 rep 122 movsq 123 movq %rdx,%rcx 124 andq $7,%rcx /* any bytes left? */ 125 rep 126 movsb 127 ret 128 129 ALIGN_TEXT 1301: 131 addq %rcx,%rdi /* copy backwards */ 132 addq %rcx,%rsi 133 decq %rdi 134 decq %rsi 135 andq $7,%rcx /* any fractional bytes? */ 136 std 137 rep 138 movsb 139 movq %rdx,%rcx /* copy by 32-bit words */ 140 shrq $3,%rcx 141 subq $7,%rsi 142 subq $7,%rdi 143 rep 144 movsq 145 cld 146 ret 147END(bcopy) 148 149ENTRY(reset_dbregs) 150 movq $0x200,%rax /* the manual says that bit 10 must be set to 1 */ 151 movq %rax,%dr7 /* disable all breapoints first */ 152 movq $0,%rax 153 movq %rax,%dr0 154 movq %rax,%dr1 155 movq %rax,%dr2 156 movq %rax,%dr3 157 movq %rax,%dr6 158 ret 159END(reset_dbregs) 160 161/* 162 * memcpy(dst:%rdi, src:%rsi, bytes:%rdx) 163 * 164 * Note: memcpy does not support overlapping copies 165 */ 166ENTRY(memcpy) 167 movq %rdi,%r8 168 movq %rdx,%rcx 169 shrq $3,%rcx /* copy by 64-bit words */ 170 cld /* copy forwards */ 171 rep 172 movsq 173 movq %rdx,%rcx 174 andq $7,%rcx /* any bytes left? */ 175 rep 176 movsb 177 movq %r8,%rax 178 ret 179END(memcpy) 180 181/* fillw(pat, base, cnt) */ 182/* %rdi,%rsi, %rdx */ 183ENTRY(fillw) 184 movq %rdi,%rax 185 movq %rsi,%rdi 186 movq %rdx,%rcx 187 cld 188 rep 189 stosw 190 ret 191END(fillw) 192 193/*****************************************************************************/ 194/* copyout and fubyte family */ 195/*****************************************************************************/ 196/* 197 * Access user memory from inside the kernel. These routines should be 198 * the only places that do this. 199 * 200 * These routines set curpcb->onfault for the time they execute. When a 201 * protection violation occurs inside the functions, the trap handler 202 * returns to *curpcb->onfault instead of the function. 203 */ 204 205/* 206 * std_copyout(from_kernel, to_user, len) - MP SAFE 207 * %rdi, %rsi, %rdx 208 */ 209ENTRY(std_copyout) 210 movq PCPU(curthread),%rax 211 movq TD_PCB(%rax), %rax 212 movq $copyout_fault,PCB_ONFAULT(%rax) 213 movq %rsp,PCB_ONFAULT_SP(%rax) 214 testq %rdx,%rdx /* anything to do? */ 215 jz done_copyout 216 217 /* 218 * Check explicitly for non-user addresses. If 486 write protection 219 * is being used, this check is essential because we are in kernel 220 * mode so the h/w does not provide any protection against writing 221 * kernel addresses. 222 */ 223 224 /* 225 * First, prevent address wrapping. 226 */ 227 movq %rsi,%rax 228 addq %rdx,%rax 229 jc copyout_fault 230/* 231 * XXX STOP USING VM_MAX_USER_ADDRESS. 232 * It is an end address, not a max, so every time it is used correctly it 233 * looks like there is an off by one error, and of course it caused an off 234 * by one error in several places. 235 */ 236 movq $VM_MAX_USER_ADDRESS,%rcx 237 cmpq %rcx,%rax 238 ja copyout_fault 239 240 xchgq %rdi,%rsi 241 /* bcopy(%rsi, %rdi, %rdx) */ 242 movq %rdx,%rcx 243 244 shrq $3,%rcx 245 cld 246 rep 247 movsq 248 movb %dl,%cl 249 andb $7,%cl 250 rep 251 movsb 252 253done_copyout: 254 xorl %eax,%eax 255 movq PCPU(curthread),%rdx 256 movq TD_PCB(%rdx), %rdx 257 movq %rax,PCB_ONFAULT(%rdx) 258 ret 259 260 ALIGN_TEXT 261copyout_fault: 262 movq PCPU(curthread),%rdx 263 movq TD_PCB(%rdx), %rdx 264 movq $0,PCB_ONFAULT(%rdx) 265 movq $EFAULT,%rax 266 ret 267END(std_copyout) 268 269/* 270 * std_copyin(from_user, to_kernel, len) - MP SAFE 271 * %rdi, %rsi, %rdx 272 */ 273ENTRY(std_copyin) 274 movq PCPU(curthread),%rax 275 movq TD_PCB(%rax), %rax 276 movq $copyin_fault,PCB_ONFAULT(%rax) 277 movq %rsp,PCB_ONFAULT_SP(%rax) 278 testq %rdx,%rdx /* anything to do? */ 279 jz done_copyin 280 281 /* 282 * make sure address is valid 283 */ 284 movq %rdi,%rax 285 addq %rdx,%rax 286 jc copyin_fault 287 movq $VM_MAX_USER_ADDRESS,%rcx 288 cmpq %rcx,%rax 289 ja copyin_fault 290 291 xchgq %rdi,%rsi 292 movq %rdx,%rcx 293 movb %cl,%al 294 shrq $3,%rcx /* copy longword-wise */ 295 cld 296 rep 297 movsq 298 movb %al,%cl 299 andb $7,%cl /* copy remaining bytes */ 300 rep 301 movsb 302 303done_copyin: 304 xorl %eax,%eax 305 movq PCPU(curthread),%rdx 306 movq TD_PCB(%rdx), %rdx 307 movq %rax,PCB_ONFAULT(%rdx) 308 ret 309 310 ALIGN_TEXT 311copyin_fault: 312 movq PCPU(curthread),%rdx 313 movq TD_PCB(%rdx), %rdx 314 movq $0,PCB_ONFAULT(%rdx) 315 movq $EFAULT,%rax 316 ret 317END(std_copyin) 318 319/* 320 * casu32 - Compare and set user integer. Returns -1 or the current value. 321 * dst = %rdi, old = %rsi, new = %rdx 322 */ 323ENTRY(casu32) 324 movq PCPU(curthread),%rcx 325 movq TD_PCB(%rcx), %rcx 326 movq $fusufault,PCB_ONFAULT(%rcx) 327 movq %rsp,PCB_ONFAULT_SP(%rcx) 328 329 movq $VM_MAX_USER_ADDRESS-4,%rax 330 cmpq %rax,%rdi /* verify address is valid */ 331 ja fusufault 332 333 movl %esi,%eax /* old */ 334 lock 335 cmpxchgl %edx,(%rdi) /* new = %edx */ 336 337 /* 338 * The old value is in %eax. If the store succeeded it will be the 339 * value we expected (old) from before the store, otherwise it will 340 * be the current value. 341 */ 342 343 movq PCPU(curthread),%rcx 344 movq TD_PCB(%rcx), %rcx 345 movq $0,PCB_ONFAULT(%rcx) 346 ret 347END(casu32) 348 349/* 350 * swapu32 - Swap int in user space. ptr = %rdi, val = %rsi 351 */ 352ENTRY(std_swapu32) 353 movq PCPU(curthread),%rcx 354 movq TD_PCB(%rcx), %rcx 355 movq $fusufault,PCB_ONFAULT(%rcx) 356 movq %rsp,PCB_ONFAULT_SP(%rcx) 357 358 movq $VM_MAX_USER_ADDRESS-4,%rax 359 cmpq %rax,%rdi /* verify address is valid */ 360 ja fusufault 361 362 movq %rsi,%rax /* old */ 363 xchgl %eax,(%rdi) 364 365 /* 366 * The old value is in %rax. If the store succeeded it will be the 367 * value we expected (old) from before the store, otherwise it will 368 * be the current value. 369 */ 370 371 movq PCPU(curthread),%rcx 372 movq TD_PCB(%rcx), %rcx 373 movq $0,PCB_ONFAULT(%rcx) 374 ret 375END(std_swapu32) 376 377/* 378 * casu64 - Compare and set user word. Returns -1 or the current value. 379 * dst = %rdi, old = %rsi, new = %rdx 380 */ 381ENTRY(casu64) 382 movq PCPU(curthread),%rcx 383 movq TD_PCB(%rcx), %rcx 384 movq $fusufault,PCB_ONFAULT(%rcx) 385 movq %rsp,PCB_ONFAULT_SP(%rcx) 386 387 movq $VM_MAX_USER_ADDRESS-8,%rax 388 cmpq %rax,%rdi /* verify address is valid */ 389 ja fusufault 390 391 movq %rsi,%rax /* old */ 392 lock 393 cmpxchgq %rdx,(%rdi) /* new = %rdx */ 394 395 /* 396 * The old value is in %rax. If the store succeeded it will be the 397 * value we expected (old) from before the store, otherwise it will 398 * be the current value. 399 */ 400 401 movq PCPU(curthread),%rcx 402 movq TD_PCB(%rcx), %rcx 403 movq $0,PCB_ONFAULT(%rcx) 404 ret 405END(casu64) 406 407/* 408 * swapu64 - Swap long in user space. ptr = %rdi, val = %rsi 409 */ 410ENTRY(std_swapu64) 411 movq PCPU(curthread),%rcx 412 movq TD_PCB(%rcx), %rcx 413 movq $fusufault,PCB_ONFAULT(%rcx) 414 movq %rsp,PCB_ONFAULT_SP(%rcx) 415 416 movq $VM_MAX_USER_ADDRESS-8,%rax 417 cmpq %rax,%rdi /* verify address is valid */ 418 ja fusufault 419 420 movq %rsi,%rax /* old */ 421 xchgq %rax,(%rdi) 422 423 /* 424 * The old value is in %rax. If the store succeeded it will be the 425 * value we expected (old) from before the store, otherwise it will 426 * be the current value. 427 */ 428 429 movq PCPU(curthread),%rcx 430 movq TD_PCB(%rcx), %rcx 431 movq $0,PCB_ONFAULT(%rcx) 432 ret 433END(std_swapu64) 434 435/* 436 * Fetch (load) a 64-bit word, a 32-bit word, a 16-bit word, or an 8-bit 437 * byte from user memory. All these functions are MPSAFE. 438 * addr = %rdi 439 */ 440 441ENTRY(std_fuword64) 442 movq PCPU(curthread),%rcx 443 movq TD_PCB(%rcx), %rcx 444 movq $fusufault,PCB_ONFAULT(%rcx) 445 movq %rsp,PCB_ONFAULT_SP(%rcx) 446 447 movq $VM_MAX_USER_ADDRESS-8,%rax 448 cmpq %rax,%rdi /* verify address is valid */ 449 ja fusufault 450 451 movq (%rdi),%rax 452 movq $0,PCB_ONFAULT(%rcx) 453 ret 454END(std_fuword64) 455 456ENTRY(std_fuword32) 457 movq PCPU(curthread),%rcx 458 movq TD_PCB(%rcx), %rcx 459 movq $fusufault,PCB_ONFAULT(%rcx) 460 movq %rsp,PCB_ONFAULT_SP(%rcx) 461 462 movq $VM_MAX_USER_ADDRESS-4,%rax 463 cmpq %rax,%rdi /* verify address is valid */ 464 ja fusufault 465 466 movl (%rdi),%eax 467 movq $0,PCB_ONFAULT(%rcx) 468 ret 469END(std_fuword32) 470 471ENTRY(std_fubyte) 472 movq PCPU(curthread),%rcx 473 movq TD_PCB(%rcx), %rcx 474 movq $fusufault,PCB_ONFAULT(%rcx) 475 movq %rsp,PCB_ONFAULT_SP(%rcx) 476 477 movq $VM_MAX_USER_ADDRESS-1,%rax 478 cmpq %rax,%rdi 479 ja fusufault 480 481 movzbl (%rdi),%eax 482 movq $0,PCB_ONFAULT(%rcx) 483 ret 484 485 ALIGN_TEXT 486fusufault: 487 movq PCPU(curthread),%rcx 488 xorl %eax,%eax 489 movq TD_PCB(%rcx), %rcx 490 movq %rax,PCB_ONFAULT(%rcx) 491 decq %rax 492 ret 493END(std_fubyte) 494 495/* 496 * Store a 64-bit word, a 32-bit word, a 16-bit word, or an 8-bit byte to 497 * user memory. All these functions are MPSAFE. 498 * 499 * addr = %rdi, value = %rsi 500 * 501 * Write a long 502 */ 503ENTRY(std_suword64) 504 movq PCPU(curthread),%rcx 505 movq TD_PCB(%rcx), %rcx 506 movq $fusufault,PCB_ONFAULT(%rcx) 507 movq %rsp,PCB_ONFAULT_SP(%rcx) 508 509 movq $VM_MAX_USER_ADDRESS-8,%rax 510 cmpq %rax,%rdi /* verify address validity */ 511 ja fusufault 512 513 movq %rsi,(%rdi) 514 xorl %eax,%eax 515 movq PCPU(curthread),%rcx 516 movq TD_PCB(%rcx), %rcx 517 movq %rax,PCB_ONFAULT(%rcx) 518 ret 519END(std_suword64) 520 521/* 522 * Write an int 523 */ 524ENTRY(std_suword32) 525 movq PCPU(curthread),%rcx 526 movq TD_PCB(%rcx), %rcx 527 movq $fusufault,PCB_ONFAULT(%rcx) 528 movq %rsp,PCB_ONFAULT_SP(%rcx) 529 530 movq $VM_MAX_USER_ADDRESS-4,%rax 531 cmpq %rax,%rdi /* verify address validity */ 532 ja fusufault 533 534 movl %esi,(%rdi) 535 xorl %eax,%eax 536 movq PCPU(curthread),%rcx 537 movq TD_PCB(%rcx), %rcx 538 movq %rax,PCB_ONFAULT(%rcx) 539 ret 540END(std_suword32) 541 542ENTRY(std_subyte) 543 movq PCPU(curthread),%rcx 544 movq TD_PCB(%rcx), %rcx 545 movq $fusufault,PCB_ONFAULT(%rcx) 546 movq %rsp,PCB_ONFAULT_SP(%rcx) 547 548 movq $VM_MAX_USER_ADDRESS-1,%rax 549 cmpq %rax,%rdi /* verify address validity */ 550 ja fusufault 551 552 movl %esi,%eax 553 movb %al,(%rdi) 554 xorl %eax,%eax 555 movq PCPU(curthread),%rcx /* restore trashed register */ 556 movq TD_PCB(%rcx), %rcx 557 movq %rax,PCB_ONFAULT(%rcx) 558 ret 559END(std_subyte) 560 561/* 562 * std_copyinstr(from, to, maxlen, int *lencopied) - MP SAFE 563 * %rdi, %rsi, %rdx, %rcx 564 * 565 * copy a string from from to to, stop when a 0 character is reached. 566 * return ENAMETOOLONG if string is longer than maxlen, and 567 * EFAULT on protection violations. If lencopied is non-zero, 568 * return the actual length in *lencopied. 569 */ 570ENTRY(std_copyinstr) 571 movq %rdx,%r8 /* %r8 = maxlen */ 572 movq %rcx,%r9 /* %r9 = *len */ 573 xchgq %rdi,%rsi /* %rdi = from, %rsi = to */ 574 movq PCPU(curthread),%rcx 575 movq TD_PCB(%rcx), %rcx 576 movq $cpystrflt,PCB_ONFAULT(%rcx) 577 movq %rsp,PCB_ONFAULT_SP(%rcx) 578 579 movq $VM_MAX_USER_ADDRESS,%rax 580 581 /* make sure 'from' is within bounds */ 582 subq %rsi,%rax 583 jbe cpystrflt 584 585 /* restrict maxlen to <= VM_MAX_USER_ADDRESS-from */ 586 cmpq %rdx,%rax 587 jae 1f 588 movq %rax,%rdx 589 movq %rax,%r8 5901: 591 incq %rdx 592 cld 593 5942: 595 decq %rdx 596 jz 3f 597 598 lodsb 599 stosb 600 orb %al,%al 601 jnz 2b 602 603 /* Success -- 0 byte reached */ 604 decq %rdx 605 xorl %eax,%eax 606 jmp cpystrflt_x 6073: 608 /* rdx is zero - return ENAMETOOLONG or EFAULT */ 609 movq $VM_MAX_USER_ADDRESS,%rax 610 cmpq %rax,%rsi 611 jae cpystrflt 6124: 613 movq $ENAMETOOLONG,%rax 614 jmp cpystrflt_x 615 616cpystrflt: 617 movq $EFAULT,%rax 618 619cpystrflt_x: 620 /* set *lencopied and return %eax */ 621 movq PCPU(curthread),%rcx 622 movq TD_PCB(%rcx), %rcx 623 movq $0,PCB_ONFAULT(%rcx) 624 625 testq %r9,%r9 626 jz 1f 627 subq %rdx,%r8 628 movq %r8,(%r9) 6291: 630 ret 631END(std_copyinstr) 632 633/* 634 * copystr(from, to, maxlen, int *lencopied) - MP SAFE 635 * %rdi, %rsi, %rdx, %rcx 636 */ 637ENTRY(copystr) 638 movq %rdx,%r8 /* %r8 = maxlen */ 639 640 xchgq %rdi,%rsi 641 incq %rdx 642 cld 6431: 644 decq %rdx 645 jz 4f 646 lodsb 647 stosb 648 orb %al,%al 649 jnz 1b 650 651 /* Success -- 0 byte reached */ 652 decq %rdx 653 xorl %eax,%eax 654 jmp 6f 6554: 656 /* rdx is zero -- return ENAMETOOLONG */ 657 movq $ENAMETOOLONG,%rax 658 6596: 660 661 testq %rcx,%rcx 662 jz 7f 663 /* set *lencopied and return %rax */ 664 subq %rdx,%r8 665 movq %r8,(%rcx) 6667: 667 ret 668END(copystr) 669 670/* 671 * Handling of special x86_64 registers and descriptor tables etc 672 * %rdi 673 */ 674/* void lgdt(struct region_descriptor *rdp); */ 675ENTRY(lgdt) 676 /* reload the descriptor table */ 677 lgdt (%rdi) 678 679 /* flush the prefetch q */ 680 jmp 1f 681 nop 6821: 683 movl $KDSEL,%eax 684 movl %eax,%ds 685 movl %eax,%es 686 movl %eax,%fs /* Beware, use wrmsr to set 64 bit base */ 687 movl %eax,%gs /* Beware, use wrmsr to set 64 bit base */ 688 movl %eax,%ss 689 690 /* reload code selector by turning return into intersegmental return */ 691 popq %rax 692 pushq $KCSEL 693 pushq %rax 694 MEXITCOUNT 695 lretq 696END(lgdt) 697 698/*****************************************************************************/ 699/* setjmp, longjmp */ 700/*****************************************************************************/ 701 702ENTRY(setjmp) 703 movq %rbx,0(%rdi) /* save rbx */ 704 movq %rsp,8(%rdi) /* save rsp */ 705 movq %rbp,16(%rdi) /* save rbp */ 706 movq %r12,24(%rdi) /* save r12 */ 707 movq %r13,32(%rdi) /* save r13 */ 708 movq %r14,40(%rdi) /* save r14 */ 709 movq %r15,48(%rdi) /* save r15 */ 710 movq 0(%rsp),%rdx /* get rta */ 711 movq %rdx,56(%rdi) /* save rip */ 712 xorl %eax,%eax /* return(0); */ 713 ret 714END(setjmp) 715 716ENTRY(longjmp) 717 movq 0(%rdi),%rbx /* restore rbx */ 718 movq 8(%rdi),%rsp /* restore rsp */ 719 movq 16(%rdi),%rbp /* restore rbp */ 720 movq 24(%rdi),%r12 /* restore r12 */ 721 movq 32(%rdi),%r13 /* restore r13 */ 722 movq 40(%rdi),%r14 /* restore r14 */ 723 movq 48(%rdi),%r15 /* restore r15 */ 724 movq 56(%rdi),%rdx /* get rta */ 725 movq %rdx,0(%rsp) /* put in return frame */ 726 xorl %eax,%eax /* return(1); */ 727 incl %eax 728 ret 729END(longjmp) 730 731/* 732 * Support for reading MSRs in the safe manner. 733 */ 734ENTRY(rdmsr_safe) 735/* int rdmsr_safe(u_int msr, uint64_t *data) */ 736 movq PCPU(curthread),%r8 737 movq TD_PCB(%r8), %r8 738 movq $msr_onfault,PCB_ONFAULT(%r8) 739 movq %rsp,PCB_ONFAULT_SP(%r8) 740 movl %edi,%ecx 741 rdmsr /* Read MSR pointed by %ecx. Returns 742 hi byte in edx, lo in %eax */ 743 salq $32,%rdx /* sign-shift %rdx left */ 744 movl %eax,%eax /* zero-extend %eax -> %rax */ 745 orq %rdx,%rax 746 movq %rax,(%rsi) 747 xorq %rax,%rax 748 movq %rax,PCB_ONFAULT(%r8) 749 ret 750END(rdmsr_safe) 751 752/* 753 * Support for writing MSRs in the safe manner. 754 */ 755ENTRY(wrmsr_safe) 756/* int wrmsr_safe(u_int msr, uint64_t data) */ 757 movq PCPU(curthread),%r8 758 movq TD_PCB(%r8), %r8 759 movq $msr_onfault,PCB_ONFAULT(%r8) 760 movq %rsp,PCB_ONFAULT_SP(%r8) 761 movl %edi,%ecx 762 movl %esi,%eax 763 sarq $32,%rsi 764 movl %esi,%edx 765 wrmsr /* Write MSR pointed by %ecx. Accepts 766 hi byte in edx, lo in %eax. */ 767 xorq %rax,%rax 768 movq %rax,PCB_ONFAULT(%r8) 769 ret 770END(wrmsr_safe) 771 772/* 773 * MSR operations fault handler 774 */ 775 ALIGN_TEXT 776msr_onfault: 777 movq PCPU(curthread),%r8 778 movq TD_PCB(%r8), %r8 779 movq $0,PCB_ONFAULT(%r8) 780 movl $EFAULT,%eax 781 ret 782