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 * 4. 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 * bcopy family 45 * void bzero(void *buf, size_t len) 46 */ 47 48/* done */ 49ENTRY(bzero) 50 movq %rsi,%rcx 51 xorl %eax,%eax 52 shrq $3,%rcx 53 cld 54 rep 55 stosq 56 movq %rsi,%rcx 57 andq $7,%rcx 58 rep 59 stosb 60 ret 61 62/* Address: %rdi */ 63ENTRY(pagezero) 64 movq $-PAGE_SIZE,%rdx 65 subq %rdx,%rdi 66 xorl %eax,%eax 671: 68 movq %rax,(%rdi,%rdx) /* movnti */ 69 movq %rax,8(%rdi,%rdx) /* movnti */ 70 movq %rax,16(%rdi,%rdx) /* movnti */ 71 movq %rax,24(%rdi,%rdx) /* movnti */ 72 addq $32,%rdx 73 jne 1b 74 /*sfence*/ 75 ret 76 77ENTRY(bcmp) 78 movq %rdx,%rcx 79 shrq $3,%rcx 80 cld /* compare forwards */ 81 repe 82 cmpsq 83 jne 1f 84 85 movq %rdx,%rcx 86 andq $7,%rcx 87 repe 88 cmpsb 891: 90 setne %al 91 movsbl %al,%eax 92 ret 93 94/* 95 * bcopy(src, dst, cnt) 96 * rdi, rsi, rdx 97 * ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800 98 */ 99ENTRY(generic_bcopy) /* generic_bcopy is bcopy without FPU */ 100ENTRY(ovbcopy) /* our bcopy doesn't use the FPU, so ovbcopy is the same */ 101ENTRY(bcopy) 102 xchgq %rsi,%rdi 103 movq %rdx,%rcx 104 105 movq %rdi,%rax 106 subq %rsi,%rax 107 cmpq %rcx,%rax /* overlapping && src < dst? */ 108 jb 1f 109 110 shrq $3,%rcx /* copy by 64-bit words */ 111 cld /* nope, copy forwards */ 112 rep 113 movsq 114 movq %rdx,%rcx 115 andq $7,%rcx /* any bytes left? */ 116 rep 117 movsb 118 ret 119 120 /* ALIGN_TEXT */ 1211: 122 addq %rcx,%rdi /* copy backwards */ 123 addq %rcx,%rsi 124 decq %rdi 125 decq %rsi 126 andq $7,%rcx /* any fractional bytes? */ 127 std 128 rep 129 movsb 130 movq %rdx,%rcx /* copy remainder by 32-bit words */ 131 shrq $3,%rcx 132 subq $7,%rsi 133 subq $7,%rdi 134 rep 135 movsq 136 cld 137 ret 138ENTRY(reset_dbregs) 139 movq $0x200,%rax /* the manual says that bit 10 must be set to 1 */ 140 movq %rax,%dr7 /* disable all breapoints first */ 141 movq $0,%rax 142 movq %rax,%dr0 143 movq %rax,%dr1 144 movq %rax,%dr2 145 movq %rax,%dr3 146 movq %rax,%dr6 147 ret 148 149/* 150 * Note: memcpy does not support overlapping copies 151 */ 152ENTRY(memcpy) 153 movq %rdx,%rcx 154 shrq $3,%rcx /* copy by 64-bit words */ 155 cld /* copy forwards */ 156 rep 157 movsq 158 movq %rdx,%rcx 159 andq $7,%rcx /* any bytes left? */ 160 rep 161 movsb 162 ret 163 164/* 165 * pagecopy(%rdi=from, %rsi=to) 166 */ 167ENTRY(pagecopy) 168 movq $-PAGE_SIZE,%rax 169 movq %rax,%rdx 170 subq %rax,%rdi 171 subq %rax,%rsi 1721: 173 /*prefetchnta (%rdi,%rax)*/ 174 /*addq $64,%rax*/ 175 /*jne 1b*/ 1762: 177 movq (%rdi,%rdx),%rax 178 movq %rax,(%rsi,%rdx) /* movnti */ 179 movq 8(%rdi,%rdx),%rax 180 movq %rax,8(%rsi,%rdx) /* movnti */ 181 movq 16(%rdi,%rdx),%rax 182 movq %rax,16(%rsi,%rdx) /* movnti */ 183 movq 24(%rdi,%rdx),%rax 184 movq %rax,24(%rsi,%rdx) /* movnti */ 185 addq $32,%rdx 186 jne 2b 187 /*sfence*/ 188 ret 189 190/* fillw(pat, base, cnt) */ 191/* %rdi,%rsi, %rdx */ 192ENTRY(fillw) 193 movq %rdi,%rax 194 movq %rsi,%rdi 195 movq %rdx,%rcx 196 cld 197 rep 198 stosw 199 ret 200 201/*****************************************************************************/ 202/* copyout and fubyte family */ 203/*****************************************************************************/ 204/* 205 * Access user memory from inside the kernel. These routines should be 206 * the only places that do this. 207 * 208 * These routines set curpcb->onfault for the time they execute. When a 209 * protection violation occurs inside the functions, the trap handler 210 * returns to *curpcb->onfault instead of the function. 211 */ 212 213/* 214 * copyout(from_kernel, to_user, len) - MP SAFE 215 * %rdi, %rsi, %rdx 216 */ 217ENTRY(copyout) 218 movq PCPU(curthread),%rax 219 movq TD_PCB(%rax), %rax 220 movq $copyout_fault,PCB_ONFAULT(%rax) 221 movq %rsp,PCB_ONFAULT_SP(%rax) 222 testq %rdx,%rdx /* anything to do? */ 223 jz done_copyout 224 225 /* 226 * Check explicitly for non-user addresses. If 486 write protection 227 * is being used, this check is essential because we are in kernel 228 * mode so the h/w does not provide any protection against writing 229 * kernel addresses. 230 */ 231 232 /* 233 * First, prevent address wrapping. 234 */ 235 movq %rsi,%rax 236 addq %rdx,%rax 237 jc copyout_fault 238/* 239 * XXX STOP USING VM_MAX_USER_ADDRESS. 240 * It is an end address, not a max, so every time it is used correctly it 241 * looks like there is an off by one error, and of course it caused an off 242 * by one error in several places. 243 */ 244 movq $VM_MAX_USER_ADDRESS,%rcx 245 cmpq %rcx,%rax 246 ja copyout_fault 247 248 xchgq %rdi,%rsi 249 /* bcopy(%rsi, %rdi, %rdx) */ 250 movq %rdx,%rcx 251 252 shrq $3,%rcx 253 cld 254 rep 255 movsq 256 movb %dl,%cl 257 andb $7,%cl 258 rep 259 movsb 260 261done_copyout: 262 xorl %eax,%eax 263 movq PCPU(curthread),%rdx 264 movq TD_PCB(%rdx), %rdx 265 movq %rax,PCB_ONFAULT(%rdx) 266 ret 267 268 ALIGN_TEXT 269copyout_fault: 270 movq PCPU(curthread),%rdx 271 movq TD_PCB(%rdx), %rdx 272 movq $0,PCB_ONFAULT(%rdx) 273 movq $EFAULT,%rax 274 ret 275 276/* 277 * copyin(from_user, to_kernel, len) - MP SAFE 278 * %rdi, %rsi, %rdx 279 */ 280ENTRY(copyin) 281 movq PCPU(curthread),%rax 282 movq TD_PCB(%rax), %rax 283 movq $copyin_fault,PCB_ONFAULT(%rax) 284 movq %rsp,PCB_ONFAULT_SP(%rax) 285 testq %rdx,%rdx /* anything to do? */ 286 jz done_copyin 287 288 /* 289 * make sure address is valid 290 */ 291 movq %rdi,%rax 292 addq %rdx,%rax 293 jc copyin_fault 294 movq $VM_MAX_USER_ADDRESS,%rcx 295 cmpq %rcx,%rax 296 ja copyin_fault 297 298 xchgq %rdi,%rsi 299 movq %rdx,%rcx 300 movb %cl,%al 301 shrq $3,%rcx /* copy longword-wise */ 302 cld 303 rep 304 movsq 305 movb %al,%cl 306 andb $7,%cl /* copy remaining bytes */ 307 rep 308 movsb 309 310done_copyin: 311 xorl %eax,%eax 312 movq PCPU(curthread),%rdx 313 movq TD_PCB(%rdx), %rdx 314 movq %rax,PCB_ONFAULT(%rdx) 315 ret 316 317 ALIGN_TEXT 318copyin_fault: 319 movq PCPU(curthread),%rdx 320 movq TD_PCB(%rdx), %rdx 321 movq $0,PCB_ONFAULT(%rdx) 322 movq $EFAULT,%rax 323 ret 324 325/* 326 * casuword32. Compare and set user integer. Returns -1 or the current value. 327 * dst = %rdi, old = %rsi, new = %rdx 328 */ 329ENTRY(casuword32) 330 movq PCPU(curthread),%rcx 331 movq TD_PCB(%rcx), %rcx 332 movq $fusufault,PCB_ONFAULT(%rcx) 333 movq %rsp,PCB_ONFAULT_SP(%rcx) 334 335 movq $VM_MAX_USER_ADDRESS-4,%rax 336 cmpq %rax,%rdi /* verify address is valid */ 337 ja fusufault 338 339 movl %esi,%eax /* old */ 340#ifdef SMP 341 lock 342#endif 343 cmpxchgl %edx,(%rdi) /* new = %edx */ 344 345 /* 346 * The old value is in %eax. If the store succeeded it will be the 347 * value we expected (old) from before the store, otherwise it will 348 * be the current value. 349 */ 350 351 movq PCPU(curthread),%rcx 352 movq TD_PCB(%rcx), %rcx 353 movq $0,PCB_ONFAULT(%rcx) 354 ret 355 356/* 357 * casuword. Compare and set user word. Returns -1 or the current value. 358 * dst = %rdi, old = %rsi, new = %rdx 359 */ 360ENTRY(casuword) 361 movq PCPU(curthread),%rcx 362 movq TD_PCB(%rcx), %rcx 363 movq $fusufault,PCB_ONFAULT(%rcx) 364 movq %rsp,PCB_ONFAULT_SP(%rcx) 365 366 movq $VM_MAX_USER_ADDRESS-4,%rax 367 cmpq %rax,%rdi /* verify address is valid */ 368 ja fusufault 369 370 movq %rsi,%rax /* old */ 371#ifdef SMP 372 lock 373#endif 374 cmpxchgq %rdx,(%rdi) /* new = %rdx */ 375 376 /* 377 * The old value is in %eax. If the store succeeded it will be the 378 * value we expected (old) from before the store, otherwise it will 379 * be the current value. 380 */ 381 382 movq PCPU(curthread),%rcx 383 movq TD_PCB(%rcx), %rcx 384 movq $0,PCB_ONFAULT(%rcx) 385 ret 386 387/* 388 * Fetch (load) a 64-bit word, a 32-bit word, a 16-bit word, or an 8-bit 389 * byte from user memory. All these functions are MPSAFE. 390 * addr = %rdi 391 */ 392 393ALTENTRY(fuword64) 394ENTRY(fuword) 395 movq PCPU(curthread),%rcx 396 movq TD_PCB(%rcx), %rcx 397 movq $fusufault,PCB_ONFAULT(%rcx) 398 movq %rsp,PCB_ONFAULT_SP(%rcx) 399 400 movq $VM_MAX_USER_ADDRESS-8,%rax 401 cmpq %rax,%rdi /* verify address is valid */ 402 ja fusufault 403 404 movq (%rdi),%rax 405 movq $0,PCB_ONFAULT(%rcx) 406 ret 407 408ENTRY(fuword32) 409 movq PCPU(curthread),%rcx 410 movq TD_PCB(%rcx), %rcx 411 movq $fusufault,PCB_ONFAULT(%rcx) 412 movq %rsp,PCB_ONFAULT_SP(%rcx) 413 414 movq $VM_MAX_USER_ADDRESS-4,%rax 415 cmpq %rax,%rdi /* verify address is valid */ 416 ja fusufault 417 418 movl (%rdi),%eax 419 movq $0,PCB_ONFAULT(%rcx) 420 ret 421 422/* 423 * fuswintr() and suswintr() are specialized variants of fuword16() and 424 * suword16(), respectively. They are called from the profiling code, 425 * potentially at interrupt time. If they fail, that's okay; good things 426 * will happen later. They always fail for now, until the trap code is 427 * able to deal with this. 428 */ 429ALTENTRY(suswintr) 430ENTRY(fuswintr) 431 movq $-1,%rax 432 ret 433 434ENTRY(fuword16) 435 movq PCPU(curthread),%rcx 436 movq TD_PCB(%rcx), %rcx 437 movq $fusufault,PCB_ONFAULT(%rcx) 438 movq %rsp,PCB_ONFAULT_SP(%rcx) 439 440 movq $VM_MAX_USER_ADDRESS-2,%rax 441 cmpq %rax,%rdi 442 ja fusufault 443 444 movzwl (%rdi),%eax 445 movq $0,PCB_ONFAULT(%rcx) 446 ret 447 448ENTRY(fubyte) 449 movq PCPU(curthread),%rcx 450 movq TD_PCB(%rcx), %rcx 451 movq $fusufault,PCB_ONFAULT(%rcx) 452 movq %rsp,PCB_ONFAULT_SP(%rcx) 453 454 movq $VM_MAX_USER_ADDRESS-1,%rax 455 cmpq %rax,%rdi 456 ja fusufault 457 458 movzbl (%rdi),%eax 459 movq $0,PCB_ONFAULT(%rcx) 460 ret 461 462 ALIGN_TEXT 463fusufault: 464 movq PCPU(curthread),%rcx 465 xorl %eax,%eax 466 movq TD_PCB(%rcx), %rcx 467 movq %rax,PCB_ONFAULT(%rcx) 468 decq %rax 469 ret 470 471/* 472 * Store a 64-bit word, a 32-bit word, a 16-bit word, or an 8-bit byte to 473 * user memory. All these functions are MPSAFE. 474 * 475 * addr = %rdi, value = %rsi 476 * 477 * Write a long 478 */ 479ALTENTRY(suword64) 480ENTRY(suword) 481 movq PCPU(curthread),%rcx 482 movq TD_PCB(%rcx), %rcx 483 movq $fusufault,PCB_ONFAULT(%rcx) 484 movq %rsp,PCB_ONFAULT_SP(%rcx) 485 486 movq $VM_MAX_USER_ADDRESS-8,%rax 487 cmpq %rax,%rdi /* verify address validity */ 488 ja fusufault 489 490 movq %rsi,(%rdi) 491 xorl %eax,%eax 492 movq PCPU(curthread),%rcx 493 movq TD_PCB(%rcx), %rcx 494 movq %rax,PCB_ONFAULT(%rcx) 495 ret 496 497/* 498 * Write an int 499 */ 500ENTRY(suword32) 501 movq PCPU(curthread),%rcx 502 movq TD_PCB(%rcx), %rcx 503 movq $fusufault,PCB_ONFAULT(%rcx) 504 movq %rsp,PCB_ONFAULT_SP(%rcx) 505 506 movq $VM_MAX_USER_ADDRESS-4,%rax 507 cmpq %rax,%rdi /* verify address validity */ 508 ja fusufault 509 510 movl %esi,(%rdi) 511 xorl %eax,%eax 512 movq PCPU(curthread),%rcx 513 movq TD_PCB(%rcx), %rcx 514 movq %rax,PCB_ONFAULT(%rcx) 515 ret 516 517ENTRY(suword16) 518 movq PCPU(curthread),%rcx 519 movq TD_PCB(%rcx), %rcx 520 movq $fusufault,PCB_ONFAULT(%rcx) 521 movq %rsp,PCB_ONFAULT_SP(%rcx) 522 523 movq $VM_MAX_USER_ADDRESS-2,%rax 524 cmpq %rax,%rdi /* verify address validity */ 525 ja fusufault 526 527 movw %si,(%rdi) 528 xorl %eax,%eax 529 movq PCPU(curthread),%rcx /* restore trashed register */ 530 movq TD_PCB(%rcx), %rcx 531 movq %rax,PCB_ONFAULT(%rcx) 532 ret 533 534ENTRY(subyte) 535 movq PCPU(curthread),%rcx 536 movq TD_PCB(%rcx), %rcx 537 movq $fusufault,PCB_ONFAULT(%rcx) 538 movq %rsp,PCB_ONFAULT_SP(%rcx) 539 540 movq $VM_MAX_USER_ADDRESS-1,%rax 541 cmpq %rax,%rdi /* verify address validity */ 542 ja fusufault 543 544 movl %esi,%eax 545 movb %al,(%rdi) 546 xorl %eax,%eax 547 movq PCPU(curthread),%rcx /* restore trashed register */ 548 movq TD_PCB(%rcx), %rcx 549 movq %rax,PCB_ONFAULT(%rcx) 550 ret 551 552/* 553 * copyinstr(from, to, maxlen, int *lencopied) - MP SAFE 554 * %rdi, %rsi, %rdx, %rcx 555 * 556 * copy a string from from to to, stop when a 0 character is reached. 557 * return ENAMETOOLONG if string is longer than maxlen, and 558 * EFAULT on protection violations. If lencopied is non-zero, 559 * return the actual length in *lencopied. 560 */ 561ENTRY(copyinstr) 562 movq %rdx,%r8 /* %r8 = maxlen */ 563 movq %rcx,%r9 /* %r9 = *len */ 564 xchgq %rdi,%rsi /* %rdi = from, %rsi = to */ 565 movq PCPU(curthread),%rcx 566 movq TD_PCB(%rcx), %rcx 567 movq $cpystrflt,PCB_ONFAULT(%rcx) 568 movq %rsp,PCB_ONFAULT_SP(%rcx) 569 570 movq $VM_MAX_USER_ADDRESS,%rax 571 572 /* make sure 'from' is within bounds */ 573 subq %rsi,%rax 574 jbe cpystrflt 575 576 /* restrict maxlen to <= VM_MAX_USER_ADDRESS-from */ 577 cmpq %rdx,%rax 578 jae 1f 579 movq %rax,%rdx 580 movq %rax,%r8 5811: 582 incq %rdx 583 cld 584 5852: 586 decq %rdx 587 jz 3f 588 589 lodsb 590 stosb 591 orb %al,%al 592 jnz 2b 593 594 /* Success -- 0 byte reached */ 595 decq %rdx 596 xorl %eax,%eax 597 jmp cpystrflt_x 5983: 599 /* rdx is zero - return ENAMETOOLONG or EFAULT */ 600 movq $VM_MAX_USER_ADDRESS,%rax 601 cmpq %rax,%rsi 602 jae cpystrflt 6034: 604 movq $ENAMETOOLONG,%rax 605 jmp cpystrflt_x 606 607cpystrflt: 608 movq $EFAULT,%rax 609 610cpystrflt_x: 611 /* set *lencopied and return %eax */ 612 movq PCPU(curthread),%rcx 613 movq TD_PCB(%rcx), %rcx 614 movq $0,PCB_ONFAULT(%rcx) 615 616 testq %r9,%r9 617 jz 1f 618 subq %rdx,%r8 619 movq %r8,(%r9) 6201: 621 ret 622 623 624/* 625 * copystr(from, to, maxlen, int *lencopied) - MP SAFE 626 * %rdi, %rsi, %rdx, %rcx 627 */ 628ENTRY(copystr) 629 movq %rdx,%r8 /* %r8 = maxlen */ 630 631 xchgq %rdi,%rsi 632 incq %rdx 633 cld 6341: 635 decq %rdx 636 jz 4f 637 lodsb 638 stosb 639 orb %al,%al 640 jnz 1b 641 642 /* Success -- 0 byte reached */ 643 decq %rdx 644 xorl %eax,%eax 645 jmp 6f 6464: 647 /* rdx is zero -- return ENAMETOOLONG */ 648 movq $ENAMETOOLONG,%rax 649 6506: 651 652 testq %rcx,%rcx 653 jz 7f 654 /* set *lencopied and return %rax */ 655 subq %rdx,%r8 656 movq %r8,(%rcx) 6577: 658 ret 659 660/* 661 * Handling of special x86_64 registers and descriptor tables etc 662 * %rdi 663 */ 664/* void lgdt(struct region_descriptor *rdp); */ 665ENTRY(lgdt) 666 /* reload the descriptor table */ 667 lgdt (%rdi) 668 669 /* flush the prefetch q */ 670 jmp 1f 671 nop 6721: 673 movl $KDSEL,%eax 674 movl %eax,%ds 675 movl %eax,%es 676 movl %eax,%fs /* Beware, use wrmsr to set 64 bit base */ 677 movl %eax,%gs /* Beware, use wrmsr to set 64 bit base */ 678 movl %eax,%ss 679 680 /* reload code selector by turning return into intersegmental return */ 681 popq %rax 682 pushq $KCSEL 683 pushq %rax 684 MEXITCOUNT 685 lretq 686 687/*****************************************************************************/ 688/* setjump, longjump */ 689/*****************************************************************************/ 690 691ENTRY(setjmp) 692 movq %rbx,0(%rdi) /* save rbx */ 693 movq %rsp,8(%rdi) /* save rsp */ 694 movq %rbp,16(%rdi) /* save rbp */ 695 movq %r12,24(%rdi) /* save r12 */ 696 movq %r13,32(%rdi) /* save r13 */ 697 movq %r14,40(%rdi) /* save r14 */ 698 movq %r15,48(%rdi) /* save r15 */ 699 movq 0(%rsp),%rdx /* get rta */ 700 movq %rdx,56(%rdi) /* save rip */ 701 xorl %eax,%eax /* return(0); */ 702 ret 703 704ENTRY(longjmp) 705 movq 0(%rdi),%rbx /* restore rbx */ 706 movq 8(%rdi),%rsp /* restore rsp */ 707 movq 16(%rdi),%rbp /* restore rbp */ 708 movq 24(%rdi),%r12 /* restore r12 */ 709 movq 32(%rdi),%r13 /* restore r13 */ 710 movq 40(%rdi),%r14 /* restore r14 */ 711 movq 48(%rdi),%r15 /* restore r15 */ 712 movq 56(%rdi),%rdx /* get rta */ 713 movq %rdx,0(%rsp) /* put in return frame */ 714 xorl %eax,%eax /* return(1); */ 715 incl %eax 716 ret 717 718/* 719 * Support for reading MSRs in the safe manner. 720 */ 721ENTRY(rdmsr_safe) 722/* int rdmsr_safe(u_int msr, uint64_t *data) */ 723 movq PCPU(curthread),%r8 724 movq TD_PCB(%r8), %r8 725 movq $msr_onfault,PCB_ONFAULT(%r8) 726 movq %rsp,PCB_ONFAULT_SP(%r8) 727 movl %edi,%ecx 728 rdmsr /* Read MSR pointed by %ecx. Returns 729 hi byte in edx, lo in %eax */ 730 salq $32,%rdx /* sign-shift %rdx left */ 731 movl %eax,%eax /* zero-extend %eax -> %rax */ 732 orq %rdx,%rax 733 movq %rax,(%rsi) 734 xorq %rax,%rax 735 movq %rax,PCB_ONFAULT(%r8) 736 ret 737 738/* 739 * MSR operations fault handler 740 */ 741 ALIGN_TEXT 742msr_onfault: 743 movq PCPU(curthread),%r8 744 movq TD_PCB(%r8), %r8 745 movq $0,PCB_ONFAULT(%r8) 746 movl $EFAULT,%eax 747 ret 748 749/* 750 * Support for BB-profiling (gcc -a). The kernbb program will extract 751 * the data from the kernel. 752 */ 753 754 .data 755 ALIGN_DATA 756 .globl bbhead 757bbhead: 758 .quad 0 759 760 .text 761NON_GPROF_ENTRY(__bb_init_func) 762 movq $1,(%rdi) 763 movq bbhead,%rax 764 movq %rax,32(%rdi) 765 movq %rdi,bbhead 766 NON_GPROF_RET 767