1 /*-
2 * Copyright (c) 2003 Peter Wemm.
3 * Copyright (c) 1993 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 4. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD: releng/9.1/sys/amd64/amd64/support.S 224187 2011-07-18 15:19:40Z attilio $
31 */
32
33 #include "opt_ddb.h"
34
35 #include <machine/asmacros.h>
36 #include <machine/intr_machdep.h>
37 #include <machine/pmap.h>
38
39 #include "assym.s"
40
41 .text
42
43 /*
44 * bcopy family
45 * void bzero(void *buf, u_int len)
46 */
47
48 /* done */
49 ENTRY(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 END(bzero)
62
63 /* Address: %rdi */
64 ENTRY(pagezero)
65 movq $-PAGE_SIZE,%rdx
66 subq %rdx,%rdi
67 xorl %eax,%eax
68 1:
69 movnti %rax,(%rdi,%rdx)
70 movnti %rax,8(%rdi,%rdx)
71 movnti %rax,16(%rdi,%rdx)
72 movnti %rax,24(%rdi,%rdx)
73 addq $32,%rdx
74 jne 1b
75 sfence
76 ret
77 END(pagezero)
78
79 ENTRY(bcmp)
80 movq %rdx,%rcx
81 shrq $3,%rcx
82 cld /* compare forwards */
83 repe
84 cmpsq
85 jne 1f
86
87 movq %rdx,%rcx
88 andq $7,%rcx
89 repe
90 cmpsb
91 1:
92 setne %al
93 movsbl %al,%eax
94 ret
95 END(bcmp)
96
97 /*
98 * bcopy(src, dst, cnt)
99 * rdi, rsi, rdx
100 * ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
101 */
102 ENTRY(bcopy)
103 xchgq %rsi,%rdi
104 movq %rdx,%rcx
105
106 movq %rdi,%rax
107 subq %rsi,%rax
108 cmpq %rcx,%rax /* overlapping && src < dst? */
109 jb 1f
110
111 shrq $3,%rcx /* copy by 64-bit words */
112 cld /* nope, copy forwards */
113 rep
114 movsq
115 movq %rdx,%rcx
116 andq $7,%rcx /* any bytes left? */
117 rep
118 movsb
119 ret
120
121 /* ALIGN_TEXT */
122 1:
123 addq %rcx,%rdi /* copy backwards */
124 addq %rcx,%rsi
125 decq %rdi
126 decq %rsi
127 andq $7,%rcx /* any fractional bytes? */
128 std
129 rep
130 movsb
131 movq %rdx,%rcx /* copy remainder by 32-bit words */
132 shrq $3,%rcx
133 subq $7,%rsi
134 subq $7,%rdi
135 rep
136 movsq
137 cld
138 ret
139 END(bcopy)
140
141 /*
142 * Note: memcpy does not support overlapping copies
143 */
144 ENTRY(memcpy)
145 movq %rdx,%rcx
146 shrq $3,%rcx /* copy by 64-bit words */
147 cld /* copy forwards */
148 rep
149 movsq
150 movq %rdx,%rcx
151 andq $7,%rcx /* any bytes left? */
152 rep
153 movsb
154 ret
155 END(memcpy)
156
157 /*
158 * pagecopy(%rdi=from, %rsi=to)
159 */
160 ENTRY(pagecopy)
161 movq $-PAGE_SIZE,%rax
162 movq %rax,%rdx
163 subq %rax,%rdi
164 subq %rax,%rsi
165 1:
166 prefetchnta (%rdi,%rax)
167 addq $64,%rax
168 jne 1b
169 2:
170 movq (%rdi,%rdx),%rax
171 movnti %rax,(%rsi,%rdx)
172 movq 8(%rdi,%rdx),%rax
173 movnti %rax,8(%rsi,%rdx)
174 movq 16(%rdi,%rdx),%rax
175 movnti %rax,16(%rsi,%rdx)
176 movq 24(%rdi,%rdx),%rax
177 movnti %rax,24(%rsi,%rdx)
178 addq $32,%rdx
179 jne 2b
180 sfence
181 ret
182 END(pagecopy)
183
184 /* fillw(pat, base, cnt) */
185 /* %rdi,%rsi, %rdx */
186 ENTRY(fillw)
187 movq %rdi,%rax
188 movq %rsi,%rdi
189 movq %rdx,%rcx
190 cld
191 rep
192 stosw
193 ret
194 END(fillw)
195
196 /*****************************************************************************/
197 /* copyout and fubyte family */
198 /*****************************************************************************/
199 /*
200 * Access user memory from inside the kernel. These routines should be
201 * the only places that do this.
202 *
203 * These routines set curpcb->onfault for the time they execute. When a
204 * protection violation occurs inside the functions, the trap handler
205 * returns to *curpcb->onfault instead of the function.
206 */
207
208 /*
209 * copyout(from_kernel, to_user, len) - MP SAFE
210 * %rdi, %rsi, %rdx
211 */
212 ENTRY(copyout)
213 movq PCPU(CURPCB),%rax
214 movq $copyout_fault,PCB_ONFAULT(%rax)
215 testq %rdx,%rdx /* anything to do? */
216 jz done_copyout
217
218 /*
219 * Check explicitly for non-user addresses. If 486 write protection
220 * is being used, this check is essential because we are in kernel
221 * mode so the h/w does not provide any protection against writing
222 * kernel addresses.
223 */
224
225 /*
226 * First, prevent address wrapping.
227 */
228 movq %rsi,%rax
229 addq %rdx,%rax
230 jc copyout_fault
231 /*
232 * XXX STOP USING VM_MAXUSER_ADDRESS.
233 * It is an end address, not a max, so every time it is used correctly it
234 * looks like there is an off by one error, and of course it caused an off
235 * by one error in several places.
236 */
237 movq $VM_MAXUSER_ADDRESS,%rcx
238 cmpq %rcx,%rax
239 ja copyout_fault
240
241 xchgq %rdi,%rsi
242 /* bcopy(%rsi, %rdi, %rdx) */
243 movq %rdx,%rcx
244
245 shrq $3,%rcx
246 cld
247 rep
248 movsq
249 movb %dl,%cl
250 andb $7,%cl
251 rep
252 movsb
253
254 done_copyout:
255 xorl %eax,%eax
256 movq PCPU(CURPCB),%rdx
257 movq %rax,PCB_ONFAULT(%rdx)
258 ret
259
260 ALIGN_TEXT
261 copyout_fault:
262 movq PCPU(CURPCB),%rdx
263 movq $0,PCB_ONFAULT(%rdx)
264 movq $EFAULT,%rax
265 ret
266 END(copyout)
267
268 /*
269 * copyin(from_user, to_kernel, len) - MP SAFE
270 * %rdi, %rsi, %rdx
271 */
272 ENTRY(copyin)
273 movq PCPU(CURPCB),%rax
274 movq $copyin_fault,PCB_ONFAULT(%rax)
275 testq %rdx,%rdx /* anything to do? */
276 jz done_copyin
277
278 /*
279 * make sure address is valid
280 */
281 movq %rdi,%rax
282 addq %rdx,%rax
283 jc copyin_fault
284 movq $VM_MAXUSER_ADDRESS,%rcx
285 cmpq %rcx,%rax
286 ja copyin_fault
287
288 xchgq %rdi,%rsi
289 movq %rdx,%rcx
290 movb %cl,%al
291 shrq $3,%rcx /* copy longword-wise */
292 cld
293 rep
294 movsq
295 movb %al,%cl
296 andb $7,%cl /* copy remaining bytes */
297 rep
298 movsb
299
300 done_copyin:
301 xorl %eax,%eax
302 movq PCPU(CURPCB),%rdx
303 movq %rax,PCB_ONFAULT(%rdx)
304 ret
305
306 ALIGN_TEXT
307 copyin_fault:
308 movq PCPU(CURPCB),%rdx
309 movq $0,PCB_ONFAULT(%rdx)
310 movq $EFAULT,%rax
311 ret
312 END(copyin)
313
314 /*
315 * casuword32. Compare and set user integer. Returns -1 or the current value.
316 * dst = %rdi, old = %rsi, new = %rdx
317 */
318 ENTRY(casuword32)
319 movq PCPU(CURPCB),%rcx
320 movq $fusufault,PCB_ONFAULT(%rcx)
321
322 movq $VM_MAXUSER_ADDRESS-4,%rax
323 cmpq %rax,%rdi /* verify address is valid */
324 ja fusufault
325
326 movl %esi,%eax /* old */
327 #ifdef SMP
328 lock
329 #endif
330 cmpxchgl %edx,(%rdi) /* new = %edx */
331
332 /*
333 * The old value is in %eax. If the store succeeded it will be the
334 * value we expected (old) from before the store, otherwise it will
335 * be the current value.
336 */
337
338 movq PCPU(CURPCB),%rcx
339 movq $0,PCB_ONFAULT(%rcx)
340 ret
341 END(casuword32)
342
343 /*
344 * casuword. Compare and set user word. Returns -1 or the current value.
345 * dst = %rdi, old = %rsi, new = %rdx
346 */
347 ENTRY(casuword)
348 movq PCPU(CURPCB),%rcx
349 movq $fusufault,PCB_ONFAULT(%rcx)
350
351 movq $VM_MAXUSER_ADDRESS-4,%rax
352 cmpq %rax,%rdi /* verify address is valid */
353 ja fusufault
354
355 movq %rsi,%rax /* old */
356 #ifdef SMP
357 lock
358 #endif
359 cmpxchgq %rdx,(%rdi) /* new = %rdx */
360
361 /*
362 * The old value is in %eax. If the store succeeded it will be the
363 * value we expected (old) from before the store, otherwise it will
364 * be the current value.
365 */
366
367 movq PCPU(CURPCB),%rcx
368 movq $fusufault,PCB_ONFAULT(%rcx)
369 movq $0,PCB_ONFAULT(%rcx)
370 ret
371 END(casuword)
372
373 /*
374 * Fetch (load) a 64-bit word, a 32-bit word, a 16-bit word, or an 8-bit
375 * byte from user memory. All these functions are MPSAFE.
376 * addr = %rdi
377 */
378
379 ALTENTRY(fuword64)
380 ENTRY(fuword)
381 movq PCPU(CURPCB),%rcx
382 movq $fusufault,PCB_ONFAULT(%rcx)
383
384 movq $VM_MAXUSER_ADDRESS-8,%rax
385 cmpq %rax,%rdi /* verify address is valid */
386 ja fusufault
387
388 movq (%rdi),%rax
389 movq $0,PCB_ONFAULT(%rcx)
390 ret
391 END(fuword64)
392 END(fuword)
393
394 ENTRY(fuword32)
395 movq PCPU(CURPCB),%rcx
396 movq $fusufault,PCB_ONFAULT(%rcx)
397
398 movq $VM_MAXUSER_ADDRESS-4,%rax
399 cmpq %rax,%rdi /* verify address is valid */
400 ja fusufault
401
402 movl (%rdi),%eax
403 movq $0,PCB_ONFAULT(%rcx)
404 ret
405 END(fuword32)
406
407 /*
408 * fuswintr() and suswintr() are specialized variants of fuword16() and
409 * suword16(), respectively. They are called from the profiling code,
410 * potentially at interrupt time. If they fail, that's okay; good things
411 * will happen later. They always fail for now, until the trap code is
412 * able to deal with this.
413 */
414 ALTENTRY(suswintr)
415 ENTRY(fuswintr)
416 movq $-1,%rax
417 ret
418 END(suswintr)
419 END(fuswintr)
420
421 ENTRY(fuword16)
422 movq PCPU(CURPCB),%rcx
423 movq $fusufault,PCB_ONFAULT(%rcx)
424
425 movq $VM_MAXUSER_ADDRESS-2,%rax
426 cmpq %rax,%rdi
427 ja fusufault
428
429 movzwl (%rdi),%eax
430 movq $0,PCB_ONFAULT(%rcx)
431 ret
432 END(fuword16)
433
434 ENTRY(fubyte)
435 movq PCPU(CURPCB),%rcx
436 movq $fusufault,PCB_ONFAULT(%rcx)
437
438 movq $VM_MAXUSER_ADDRESS-1,%rax
439 cmpq %rax,%rdi
440 ja fusufault
441
442 movzbl (%rdi),%eax
443 movq $0,PCB_ONFAULT(%rcx)
444 ret
445 END(fubyte)
446
447 ALIGN_TEXT
448 fusufault:
449 movq PCPU(CURPCB),%rcx
450 xorl %eax,%eax
451 movq %rax,PCB_ONFAULT(%rcx)
452 decq %rax
453 ret
454
455 /*
456 * Store a 64-bit word, a 32-bit word, a 16-bit word, or an 8-bit byte to
457 * user memory. All these functions are MPSAFE.
458 * addr = %rdi, value = %rsi
459 */
460 ALTENTRY(suword64)
461 ENTRY(suword)
462 movq PCPU(CURPCB),%rcx
463 movq $fusufault,PCB_ONFAULT(%rcx)
464
465 movq $VM_MAXUSER_ADDRESS-8,%rax
466 cmpq %rax,%rdi /* verify address validity */
467 ja fusufault
468
469 movq %rsi,(%rdi)
470 xorl %eax,%eax
471 movq PCPU(CURPCB),%rcx
472 movq %rax,PCB_ONFAULT(%rcx)
473 ret
474 END(suword64)
475 END(suword)
476
477 ENTRY(suword32)
478 movq PCPU(CURPCB),%rcx
479 movq $fusufault,PCB_ONFAULT(%rcx)
480
481 movq $VM_MAXUSER_ADDRESS-4,%rax
482 cmpq %rax,%rdi /* verify address validity */
483 ja fusufault
484
485 movl %esi,(%rdi)
486 xorl %eax,%eax
487 movq PCPU(CURPCB),%rcx
488 movq %rax,PCB_ONFAULT(%rcx)
489 ret
490 END(suword32)
491
492 ENTRY(suword16)
493 movq PCPU(CURPCB),%rcx
494 movq $fusufault,PCB_ONFAULT(%rcx)
495
496 movq $VM_MAXUSER_ADDRESS-2,%rax
497 cmpq %rax,%rdi /* verify address validity */
498 ja fusufault
499
500 movw %si,(%rdi)
501 xorl %eax,%eax
502 movq PCPU(CURPCB),%rcx /* restore trashed register */
503 movq %rax,PCB_ONFAULT(%rcx)
504 ret
505 END(suword16)
506
507 ENTRY(subyte)
508 movq PCPU(CURPCB),%rcx
509 movq $fusufault,PCB_ONFAULT(%rcx)
510
511 movq $VM_MAXUSER_ADDRESS-1,%rax
512 cmpq %rax,%rdi /* verify address validity */
513 ja fusufault
514
515 movl %esi,%eax
516 movb %al,(%rdi)
517 xorl %eax,%eax
518 movq PCPU(CURPCB),%rcx /* restore trashed register */
519 movq %rax,PCB_ONFAULT(%rcx)
520 ret
521 END(subyte)
522
523 /*
524 * copyinstr(from, to, maxlen, int *lencopied) - MP SAFE
525 * %rdi, %rsi, %rdx, %rcx
526 *
527 * copy a string from from to to, stop when a 0 character is reached.
528 * return ENAMETOOLONG if string is longer than maxlen, and
529 * EFAULT on protection violations. If lencopied is non-zero,
530 * return the actual length in *lencopied.
531 */
532 ENTRY(copyinstr)
533 movq %rdx,%r8 /* %r8 = maxlen */
534 movq %rcx,%r9 /* %r9 = *len */
535 xchgq %rdi,%rsi /* %rdi = from, %rsi = to */
536 movq PCPU(CURPCB),%rcx
537 movq $cpystrflt,PCB_ONFAULT(%rcx)
538
539 movq $VM_MAXUSER_ADDRESS,%rax
540
541 /* make sure 'from' is within bounds */
542 subq %rsi,%rax
543 jbe cpystrflt
544
545 /* restrict maxlen to <= VM_MAXUSER_ADDRESS-from */
546 cmpq %rdx,%rax
547 jae 1f
548 movq %rax,%rdx
549 movq %rax,%r8
550 1:
551 incq %rdx
552 cld
553
554 2:
555 decq %rdx
556 jz 3f
557
558 lodsb
559 stosb
560 orb %al,%al
561 jnz 2b
562
563 /* Success -- 0 byte reached */
564 decq %rdx
565 xorl %eax,%eax
566 jmp cpystrflt_x
567 3:
568 /* rdx is zero - return ENAMETOOLONG or EFAULT */
569 movq $VM_MAXUSER_ADDRESS,%rax
570 cmpq %rax,%rsi
571 jae cpystrflt
572 4:
573 movq $ENAMETOOLONG,%rax
574 jmp cpystrflt_x
575
576 cpystrflt:
577 movq $EFAULT,%rax
578
579 cpystrflt_x:
580 /* set *lencopied and return %eax */
581 movq PCPU(CURPCB),%rcx
582 movq $0,PCB_ONFAULT(%rcx)
583
584 testq %r9,%r9
585 jz 1f
586 subq %rdx,%r8
587 movq %r8,(%r9)
588 1:
589 ret
590 END(copyinstr)
591
592 /*
593 * copystr(from, to, maxlen, int *lencopied) - MP SAFE
594 * %rdi, %rsi, %rdx, %rcx
595 */
596 ENTRY(copystr)
597 movq %rdx,%r8 /* %r8 = maxlen */
598
599 xchgq %rdi,%rsi
600 incq %rdx
601 cld
602 1:
603 decq %rdx
604 jz 4f
605 lodsb
606 stosb
607 orb %al,%al
608 jnz 1b
609
610 /* Success -- 0 byte reached */
611 decq %rdx
612 xorl %eax,%eax
613 jmp 6f
614 4:
615 /* rdx is zero -- return ENAMETOOLONG */
616 movq $ENAMETOOLONG,%rax
617
618 6:
619
620 testq %rcx,%rcx
621 jz 7f
622 /* set *lencopied and return %rax */
623 subq %rdx,%r8
624 movq %r8,(%rcx)
625 7:
626 ret
627 END(copystr)
628
629 /*
630 * Handling of special amd64 registers and descriptor tables etc
631 * %rdi
632 */
633 /* void lgdt(struct region_descriptor *rdp); */
634 ENTRY(lgdt)
635 /* reload the descriptor table */
636 lgdt (%rdi)
637
638 /* flush the prefetch q */
639 jmp 1f
640 nop
641 1:
642 movl $KDSEL,%eax
643 movl %eax,%ds
644 movl %eax,%es
645 movl %eax,%fs /* Beware, use wrmsr to set 64 bit base */
646 movl %eax,%gs
647 movl %eax,%ss
648
649 /* reload code selector by turning return into intersegmental return */
650 popq %rax
651 pushq $KCSEL
652 pushq %rax
653 MEXITCOUNT
654 lretq
655 END(lgdt)
656
657 /*****************************************************************************/
658 /* setjump, longjump */
659 /*****************************************************************************/
660
661 ENTRY(setjmp)
662 movq %rbx,0(%rdi) /* save rbx */
663 movq %rsp,8(%rdi) /* save rsp */
664 movq %rbp,16(%rdi) /* save rbp */
665 movq %r12,24(%rdi) /* save r12 */
666 movq %r13,32(%rdi) /* save r13 */
667 movq %r14,40(%rdi) /* save r14 */
668 movq %r15,48(%rdi) /* save r15 */
669 movq 0(%rsp),%rdx /* get rta */
670 movq %rdx,56(%rdi) /* save rip */
671 xorl %eax,%eax /* return(0); */
672 ret
673 END(setjmp)
674
675 ENTRY(longjmp)
676 movq 0(%rdi),%rbx /* restore rbx */
677 movq 8(%rdi),%rsp /* restore rsp */
678 movq 16(%rdi),%rbp /* restore rbp */
679 movq 24(%rdi),%r12 /* restore r12 */
680 movq 32(%rdi),%r13 /* restore r13 */
681 movq 40(%rdi),%r14 /* restore r14 */
682 movq 48(%rdi),%r15 /* restore r15 */
683 movq 56(%rdi),%rdx /* get rta */
684 movq %rdx,0(%rsp) /* put in return frame */
685 xorl %eax,%eax /* return(1); */
686 incl %eax
687 ret
688 END(longjmp)
689
690 /*
691 * Support for reading MSRs in the safe manner.
692 */
693 ENTRY(rdmsr_safe)
694 /* int rdmsr_safe(u_int msr, uint64_t *data) */
695 movq PCPU(CURPCB),%r8
696 movq $msr_onfault,PCB_ONFAULT(%r8)
697 movl %edi,%ecx
698 rdmsr /* Read MSR pointed by %ecx. Returns
699 hi byte in edx, lo in %eax */
700 salq $32,%rdx /* sign-shift %rdx left */
701 movl %eax,%eax /* zero-extend %eax -> %rax */
702 orq %rdx,%rax
703 movq %rax,(%rsi)
704 xorq %rax,%rax
705 movq %rax,PCB_ONFAULT(%r8)
706 ret
707
708 /*
709 * Support for writing MSRs in the safe manner.
710 */
711 ENTRY(wrmsr_safe)
712 /* int wrmsr_safe(u_int msr, uint64_t data) */
713 movq PCPU(CURPCB),%r8
714 movq $msr_onfault,PCB_ONFAULT(%r8)
715 movl %edi,%ecx
716 movl %esi,%eax
717 sarq $32,%rsi
718 movl %esi,%edx
719 wrmsr /* Write MSR pointed by %ecx. Accepts
720 hi byte in edx, lo in %eax. */
721 xorq %rax,%rax
722 movq %rax,PCB_ONFAULT(%r8)
723 ret
724
725 /*
726 * MSR operations fault handler
727 */
728 ALIGN_TEXT
729 msr_onfault:
730 movq $0,PCB_ONFAULT(%r8)
731 movl $EFAULT,%eax
732 ret
Cache object: 07a757134f205710db2012bf0fec30b9
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