xref: /netbsd-src/sys/uvm/uvm_mmap.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /*	$NetBSD: uvm_mmap.c,v 1.169 2017/12/19 18:34:47 kamil Exp $	*/
2 
3 /*
4  * Copyright (c) 1997 Charles D. Cranor and Washington University.
5  * Copyright (c) 1991, 1993 The Regents of the University of California.
6  * Copyright (c) 1988 University of Utah.
7  *
8  * All rights reserved.
9  *
10  * This code is derived from software contributed to Berkeley by
11  * the Systems Programming Group of the University of Utah Computer
12  * Science Department.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  * 3. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  * from: Utah $Hdr: vm_mmap.c 1.6 91/10/21$
39  *      @(#)vm_mmap.c   8.5 (Berkeley) 5/19/94
40  * from: Id: uvm_mmap.c,v 1.1.2.14 1998/01/05 21:04:26 chuck Exp
41  */
42 
43 /*
44  * uvm_mmap.c: system call interface into VM system, plus kernel vm_mmap
45  * function.
46  */
47 
48 #include <sys/cdefs.h>
49 __KERNEL_RCSID(0, "$NetBSD: uvm_mmap.c,v 1.169 2017/12/19 18:34:47 kamil Exp $");
50 
51 #include "opt_compat_netbsd.h"
52 #include "opt_pax.h"
53 
54 #include <sys/types.h>
55 #include <sys/file.h>
56 #include <sys/filedesc.h>
57 #include <sys/resourcevar.h>
58 #include <sys/mman.h>
59 #include <sys/pax.h>
60 
61 #include <sys/syscallargs.h>
62 
63 #include <uvm/uvm.h>
64 #include <uvm/uvm_device.h>
65 
66 static int uvm_mmap(struct vm_map *, vaddr_t *, vsize_t, vm_prot_t, vm_prot_t,
67     int, int, struct uvm_object *, voff_t, vsize_t);
68 
69 static int
70 range_test(struct vm_map *map, vaddr_t addr, vsize_t size, bool ismmap)
71 {
72 	vaddr_t vm_min_address = vm_map_min(map);
73 	vaddr_t vm_max_address = vm_map_max(map);
74 	vaddr_t eaddr = addr + size;
75 	int res = 0;
76 
77 	if (addr < vm_min_address)
78 		return EINVAL;
79 	if (eaddr > vm_max_address)
80 		return ismmap ? EFBIG : EINVAL;
81 	if (addr > eaddr) /* no wrapping! */
82 		return ismmap ? EOVERFLOW : EINVAL;
83 
84 #ifdef MD_MMAP_RANGE_TEST
85 	res = MD_MMAP_RANGE_TEST(addr, eaddr);
86 #endif
87 
88 	return res;
89 }
90 
91 /*
92  * sys_mincore: determine if pages are in core or not.
93  */
94 
95 /* ARGSUSED */
96 int
97 sys_mincore(struct lwp *l, const struct sys_mincore_args *uap,
98     register_t *retval)
99 {
100 	/* {
101 		syscallarg(void *) addr;
102 		syscallarg(size_t) len;
103 		syscallarg(char *) vec;
104 	} */
105 	struct proc *p = l->l_proc;
106 	struct vm_page *pg;
107 	char *vec, pgi;
108 	struct uvm_object *uobj;
109 	struct vm_amap *amap;
110 	struct vm_anon *anon;
111 	struct vm_map_entry *entry;
112 	vaddr_t start, end, lim;
113 	struct vm_map *map;
114 	vsize_t len;
115 	int error = 0, npgs;
116 
117 	map = &p->p_vmspace->vm_map;
118 
119 	start = (vaddr_t)SCARG(uap, addr);
120 	len = SCARG(uap, len);
121 	vec = SCARG(uap, vec);
122 
123 	if (start & PAGE_MASK)
124 		return EINVAL;
125 	len = round_page(len);
126 	end = start + len;
127 	if (end <= start)
128 		return EINVAL;
129 
130 	/*
131 	 * Lock down vec, so our returned status isn't outdated by
132 	 * storing the status byte for a page.
133 	 */
134 
135 	npgs = len >> PAGE_SHIFT;
136 	error = uvm_vslock(p->p_vmspace, vec, npgs, VM_PROT_WRITE);
137 	if (error) {
138 		return error;
139 	}
140 	vm_map_lock_read(map);
141 
142 	if (uvm_map_lookup_entry(map, start, &entry) == false) {
143 		error = ENOMEM;
144 		goto out;
145 	}
146 
147 	for (/* nothing */;
148 	     entry != &map->header && entry->start < end;
149 	     entry = entry->next) {
150 		KASSERT(!UVM_ET_ISSUBMAP(entry));
151 		KASSERT(start >= entry->start);
152 
153 		/* Make sure there are no holes. */
154 		if (entry->end < end &&
155 		     (entry->next == &map->header ||
156 		      entry->next->start > entry->end)) {
157 			error = ENOMEM;
158 			goto out;
159 		}
160 
161 		lim = end < entry->end ? end : entry->end;
162 
163 		/*
164 		 * Special case for objects with no "real" pages.  Those
165 		 * are always considered resident (mapped devices).
166 		 */
167 
168 		if (UVM_ET_ISOBJ(entry)) {
169 			KASSERT(!UVM_OBJ_IS_KERN_OBJECT(entry->object.uvm_obj));
170 			if (UVM_OBJ_IS_DEVICE(entry->object.uvm_obj)) {
171 				for (/* nothing */; start < lim;
172 				     start += PAGE_SIZE, vec++)
173 					subyte(vec, 1);
174 				continue;
175 			}
176 		}
177 
178 		amap = entry->aref.ar_amap;	/* upper layer */
179 		uobj = entry->object.uvm_obj;	/* lower layer */
180 
181 		if (amap != NULL)
182 			amap_lock(amap);
183 		if (uobj != NULL)
184 			mutex_enter(uobj->vmobjlock);
185 
186 		for (/* nothing */; start < lim; start += PAGE_SIZE, vec++) {
187 			pgi = 0;
188 			if (amap != NULL) {
189 				/* Check the upper layer first. */
190 				anon = amap_lookup(&entry->aref,
191 				    start - entry->start);
192 				/* Don't need to lock anon here. */
193 				if (anon != NULL && anon->an_page != NULL) {
194 
195 					/*
196 					 * Anon has the page for this entry
197 					 * offset.
198 					 */
199 
200 					pgi = 1;
201 				}
202 			}
203 			if (uobj != NULL && pgi == 0) {
204 				/* Check the lower layer. */
205 				pg = uvm_pagelookup(uobj,
206 				    entry->offset + (start - entry->start));
207 				if (pg != NULL) {
208 
209 					/*
210 					 * Object has the page for this entry
211 					 * offset.
212 					 */
213 
214 					pgi = 1;
215 				}
216 			}
217 			(void) subyte(vec, pgi);
218 		}
219 		if (uobj != NULL)
220 			mutex_exit(uobj->vmobjlock);
221 		if (amap != NULL)
222 			amap_unlock(amap);
223 	}
224 
225  out:
226 	vm_map_unlock_read(map);
227 	uvm_vsunlock(p->p_vmspace, SCARG(uap, vec), npgs);
228 	return error;
229 }
230 
231 /*
232  * sys_mmap: mmap system call.
233  *
234  * => file offset and address may not be page aligned
235  *    - if MAP_FIXED, offset and address must have remainder mod PAGE_SIZE
236  *    - if address isn't page aligned the mapping starts at trunc_page(addr)
237  *      and the return value is adjusted up by the page offset.
238  */
239 
240 int
241 sys_mmap(struct lwp *l, const struct sys_mmap_args *uap, register_t *retval)
242 {
243 	/* {
244 		syscallarg(void *) addr;
245 		syscallarg(size_t) len;
246 		syscallarg(int) prot;
247 		syscallarg(int) flags;
248 		syscallarg(int) fd;
249 		syscallarg(long) pad;
250 		syscallarg(off_t) pos;
251 	} */
252 	struct proc *p = l->l_proc;
253 	vaddr_t addr;
254 	off_t pos;
255 	vsize_t size, pageoff, newsize;
256 	vm_prot_t prot, maxprot, extraprot;
257 	int flags, fd, advice;
258 	vaddr_t defaddr;
259 	struct file *fp = NULL;
260 	struct uvm_object *uobj;
261 	int error;
262 #ifdef PAX_ASLR
263 	vaddr_t orig_addr;
264 #endif /* PAX_ASLR */
265 
266 	/*
267 	 * first, extract syscall args from the uap.
268 	 */
269 
270 	addr = (vaddr_t)SCARG(uap, addr);
271 	size = (vsize_t)SCARG(uap, len);
272 	prot = SCARG(uap, prot) & VM_PROT_ALL;
273 	extraprot = PROT_MPROTECT_EXTRACT(SCARG(uap, prot));
274 	flags = SCARG(uap, flags);
275 	fd = SCARG(uap, fd);
276 	pos = SCARG(uap, pos);
277 
278 #ifdef PAX_ASLR
279 	orig_addr = addr;
280 #endif /* PAX_ASLR */
281 
282 	if ((flags & (MAP_SHARED|MAP_PRIVATE)) == (MAP_SHARED|MAP_PRIVATE))
283 		return EINVAL;
284 
285 	/*
286 	 * align file position and save offset.  adjust size.
287 	 */
288 
289 	pageoff = (pos & PAGE_MASK);
290 	pos    -= pageoff;
291 	newsize = size + pageoff;		/* add offset */
292 	newsize = (vsize_t)round_page(newsize);	/* round up */
293 
294 	if (newsize < size)
295 		return ENOMEM;
296 	size = newsize;
297 
298 	/*
299 	 * now check (MAP_FIXED) or get (!MAP_FIXED) the "addr"
300 	 */
301 	if (flags & MAP_FIXED) {
302 		/* ensure address and file offset are aligned properly */
303 		addr -= pageoff;
304 		if (addr & PAGE_MASK)
305 			return EINVAL;
306 
307 		error = range_test(&p->p_vmspace->vm_map, addr, size, true);
308 		if (error) {
309 			return error;
310 		}
311 	} else if (addr == 0 || !(flags & MAP_TRYFIXED)) {
312 		/*
313 		 * not fixed: make sure we skip over the largest
314 		 * possible heap for non-topdown mapping arrangements.
315 		 * we will refine our guess later (e.g. to account for
316 		 * VAC, etc)
317 		 */
318 
319 		defaddr = p->p_emul->e_vm_default_addr(p,
320 		    (vaddr_t)p->p_vmspace->vm_daddr, size,
321 		    p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN);
322 
323 		if (addr == 0 || !(p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN))
324 			addr = MAX(addr, defaddr);
325 		else
326 			addr = MIN(addr, defaddr);
327 	}
328 
329 	/*
330 	 * check for file mappings (i.e. not anonymous) and verify file.
331 	 */
332 
333 	advice = UVM_ADV_NORMAL;
334 	if ((flags & MAP_ANON) == 0) {
335 		if ((fp = fd_getfile(fd)) == NULL)
336 			return EBADF;
337 
338 		if (fp->f_ops->fo_mmap == NULL) {
339 			error = ENODEV;
340 			goto out;
341 		}
342 		error = (*fp->f_ops->fo_mmap)(fp, &pos, size, prot, &flags,
343 		    &advice, &uobj, &maxprot);
344 		if (error) {
345 			goto out;
346 		}
347 		if (uobj == NULL) {
348 			flags |= MAP_ANON;
349 			fd_putfile(fd);
350 			fp = NULL;
351 			goto is_anon;
352 		}
353 	} else {		/* MAP_ANON case */
354 		/*
355 		 * XXX What do we do about (MAP_SHARED|MAP_PRIVATE) == 0?
356 		 */
357 		if (fd != -1)
358 			return EINVAL;
359 
360  is_anon:		/* label for SunOS style /dev/zero */
361 		uobj = NULL;
362 		maxprot = VM_PROT_ALL;
363 		pos = 0;
364 	}
365 
366 	maxprot = PAX_MPROTECT_MAXPROTECT(l, prot, extraprot, maxprot);
367 	if (((prot | extraprot) & maxprot) != (prot | extraprot)) {
368 		error = EACCES;
369 		goto out;
370 	}
371 	if ((error = PAX_MPROTECT_VALIDATE(l, prot)))
372 		goto out;
373 
374 	pax_aslr_mmap(l, &addr, orig_addr, flags);
375 
376 	/*
377 	 * now let kernel internal function uvm_mmap do the work.
378 	 */
379 
380 	error = uvm_mmap(&p->p_vmspace->vm_map, &addr, size, prot, maxprot,
381 	    flags, advice, uobj, pos, p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
382 
383 	/* remember to add offset */
384 	*retval = (register_t)(addr + pageoff);
385 
386  out:
387 	if (fp != NULL)
388 		fd_putfile(fd);
389 
390 	return error;
391 }
392 
393 /*
394  * sys___msync13: the msync system call (a front-end for flush)
395  */
396 
397 int
398 sys___msync13(struct lwp *l, const struct sys___msync13_args *uap,
399     register_t *retval)
400 {
401 	/* {
402 		syscallarg(void *) addr;
403 		syscallarg(size_t) len;
404 		syscallarg(int) flags;
405 	} */
406 	struct proc *p = l->l_proc;
407 	vaddr_t addr;
408 	vsize_t size, pageoff;
409 	struct vm_map *map;
410 	int error, flags, uvmflags;
411 	bool rv;
412 
413 	/*
414 	 * extract syscall args from the uap
415 	 */
416 
417 	addr = (vaddr_t)SCARG(uap, addr);
418 	size = (vsize_t)SCARG(uap, len);
419 	flags = SCARG(uap, flags);
420 
421 	/* sanity check flags */
422 	if ((flags & ~(MS_ASYNC | MS_SYNC | MS_INVALIDATE)) != 0 ||
423 	    (flags & (MS_ASYNC | MS_SYNC | MS_INVALIDATE)) == 0 ||
424 	    (flags & (MS_ASYNC | MS_SYNC)) == (MS_ASYNC | MS_SYNC))
425 		return EINVAL;
426 	if ((flags & (MS_ASYNC | MS_SYNC)) == 0)
427 		flags |= MS_SYNC;
428 
429 	/*
430 	 * align the address to a page boundary and adjust the size accordingly.
431 	 */
432 
433 	pageoff = (addr & PAGE_MASK);
434 	addr -= pageoff;
435 	size += pageoff;
436 	size = (vsize_t)round_page(size);
437 
438 
439 	/*
440 	 * get map
441 	 */
442 	map = &p->p_vmspace->vm_map;
443 
444 	error = range_test(map, addr, size, false);
445 	if (error)
446 		return ENOMEM;
447 
448 	/*
449 	 * XXXCDC: do we really need this semantic?
450 	 *
451 	 * XXX Gak!  If size is zero we are supposed to sync "all modified
452 	 * pages with the region containing addr".  Unfortunately, we
453 	 * don't really keep track of individual mmaps so we approximate
454 	 * by flushing the range of the map entry containing addr.
455 	 * This can be incorrect if the region splits or is coalesced
456 	 * with a neighbor.
457 	 */
458 
459 	if (size == 0) {
460 		struct vm_map_entry *entry;
461 
462 		vm_map_lock_read(map);
463 		rv = uvm_map_lookup_entry(map, addr, &entry);
464 		if (rv == true) {
465 			addr = entry->start;
466 			size = entry->end - entry->start;
467 		}
468 		vm_map_unlock_read(map);
469 		if (rv == false)
470 			return EINVAL;
471 	}
472 
473 	/*
474 	 * translate MS_ flags into PGO_ flags
475 	 */
476 
477 	uvmflags = PGO_CLEANIT;
478 	if (flags & MS_INVALIDATE)
479 		uvmflags |= PGO_FREE;
480 	if (flags & MS_SYNC)
481 		uvmflags |= PGO_SYNCIO;
482 
483 	error = uvm_map_clean(map, addr, addr+size, uvmflags);
484 	return error;
485 }
486 
487 /*
488  * sys_munmap: unmap a users memory
489  */
490 
491 int
492 sys_munmap(struct lwp *l, const struct sys_munmap_args *uap, register_t *retval)
493 {
494 	/* {
495 		syscallarg(void *) addr;
496 		syscallarg(size_t) len;
497 	} */
498 	struct proc *p = l->l_proc;
499 	vaddr_t addr;
500 	vsize_t size, pageoff;
501 	struct vm_map *map;
502 	struct vm_map_entry *dead_entries;
503 	int error;
504 
505 	/*
506 	 * get syscall args.
507 	 */
508 
509 	addr = (vaddr_t)SCARG(uap, addr);
510 	size = (vsize_t)SCARG(uap, len);
511 
512 	/*
513 	 * align the address to a page boundary and adjust the size accordingly.
514 	 */
515 
516 	pageoff = (addr & PAGE_MASK);
517 	addr -= pageoff;
518 	size += pageoff;
519 	size = (vsize_t)round_page(size);
520 
521 	if (size == 0)
522 		return 0;
523 
524 	map = &p->p_vmspace->vm_map;
525 
526 	error = range_test(map, addr, size, false);
527 	if (error)
528 		return EINVAL;
529 
530 	vm_map_lock(map);
531 #if 0
532 	/*
533 	 * interesting system call semantic: make sure entire range is
534 	 * allocated before allowing an unmap.
535 	 */
536 	if (!uvm_map_checkprot(map, addr, addr + size, VM_PROT_NONE)) {
537 		vm_map_unlock(map);
538 		return EINVAL;
539 	}
540 #endif
541 	uvm_unmap_remove(map, addr, addr + size, &dead_entries, 0);
542 	vm_map_unlock(map);
543 	if (dead_entries != NULL)
544 		uvm_unmap_detach(dead_entries, 0);
545 	return 0;
546 }
547 
548 /*
549  * sys_mprotect: the mprotect system call
550  */
551 
552 int
553 sys_mprotect(struct lwp *l, const struct sys_mprotect_args *uap,
554     register_t *retval)
555 {
556 	/* {
557 		syscallarg(void *) addr;
558 		syscallarg(size_t) len;
559 		syscallarg(int) prot;
560 	} */
561 	struct proc *p = l->l_proc;
562 	vaddr_t addr;
563 	vsize_t size, pageoff;
564 	vm_prot_t prot;
565 	int error;
566 
567 	/*
568 	 * extract syscall args from uap
569 	 */
570 
571 	addr = (vaddr_t)SCARG(uap, addr);
572 	size = (vsize_t)SCARG(uap, len);
573 	prot = SCARG(uap, prot) & VM_PROT_ALL;
574 
575 	/*
576 	 * align the address to a page boundary and adjust the size accordingly.
577 	 */
578 
579 	pageoff = (addr & PAGE_MASK);
580 	addr -= pageoff;
581 	size += pageoff;
582 	size = round_page(size);
583 
584 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
585 	if (error)
586 		return EINVAL;
587 
588 	error = uvm_map_protect_user(l, addr, addr + size, prot);
589 	return error;
590 }
591 
592 /*
593  * sys_minherit: the minherit system call
594  */
595 
596 int
597 sys_minherit(struct lwp *l, const struct sys_minherit_args *uap,
598    register_t *retval)
599 {
600 	/* {
601 		syscallarg(void *) addr;
602 		syscallarg(int) len;
603 		syscallarg(int) inherit;
604 	} */
605 	struct proc *p = l->l_proc;
606 	vaddr_t addr;
607 	vsize_t size, pageoff;
608 	vm_inherit_t inherit;
609 	int error;
610 
611 	addr = (vaddr_t)SCARG(uap, addr);
612 	size = (vsize_t)SCARG(uap, len);
613 	inherit = SCARG(uap, inherit);
614 
615 	/*
616 	 * align the address to a page boundary and adjust the size accordingly.
617 	 */
618 
619 	pageoff = (addr & PAGE_MASK);
620 	addr -= pageoff;
621 	size += pageoff;
622 	size = (vsize_t)round_page(size);
623 
624 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
625 	if (error)
626 		return EINVAL;
627 
628 	error = uvm_map_inherit(&p->p_vmspace->vm_map, addr, addr + size,
629 	    inherit);
630 	return error;
631 }
632 
633 /*
634  * sys_madvise: give advice about memory usage.
635  */
636 
637 /* ARGSUSED */
638 int
639 sys_madvise(struct lwp *l, const struct sys_madvise_args *uap,
640    register_t *retval)
641 {
642 	/* {
643 		syscallarg(void *) addr;
644 		syscallarg(size_t) len;
645 		syscallarg(int) behav;
646 	} */
647 	struct proc *p = l->l_proc;
648 	vaddr_t addr;
649 	vsize_t size, pageoff;
650 	int advice, error;
651 
652 	addr = (vaddr_t)SCARG(uap, addr);
653 	size = (vsize_t)SCARG(uap, len);
654 	advice = SCARG(uap, behav);
655 
656 	/*
657 	 * align the address to a page boundary, and adjust the size accordingly
658 	 */
659 
660 	pageoff = (addr & PAGE_MASK);
661 	addr -= pageoff;
662 	size += pageoff;
663 	size = (vsize_t)round_page(size);
664 
665 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
666 	if (error)
667 		return EINVAL;
668 
669 	switch (advice) {
670 	case MADV_NORMAL:
671 	case MADV_RANDOM:
672 	case MADV_SEQUENTIAL:
673 		error = uvm_map_advice(&p->p_vmspace->vm_map, addr, addr + size,
674 		    advice);
675 		break;
676 
677 	case MADV_WILLNEED:
678 
679 		/*
680 		 * Activate all these pages, pre-faulting them in if
681 		 * necessary.
682 		 */
683 		error = uvm_map_willneed(&p->p_vmspace->vm_map,
684 		    addr, addr + size);
685 		break;
686 
687 	case MADV_DONTNEED:
688 
689 		/*
690 		 * Deactivate all these pages.  We don't need them
691 		 * any more.  We don't, however, toss the data in
692 		 * the pages.
693 		 */
694 
695 		error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size,
696 		    PGO_DEACTIVATE);
697 		break;
698 
699 	case MADV_FREE:
700 
701 		/*
702 		 * These pages contain no valid data, and may be
703 		 * garbage-collected.  Toss all resources, including
704 		 * any swap space in use.
705 		 */
706 
707 		error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size,
708 		    PGO_FREE);
709 		break;
710 
711 	case MADV_SPACEAVAIL:
712 
713 		/*
714 		 * XXXMRG What is this?  I think it's:
715 		 *
716 		 *	Ensure that we have allocated backing-store
717 		 *	for these pages.
718 		 *
719 		 * This is going to require changes to the page daemon,
720 		 * as it will free swap space allocated to pages in core.
721 		 * There's also what to do for device/file/anonymous memory.
722 		 */
723 
724 		return EINVAL;
725 
726 	default:
727 		return EINVAL;
728 	}
729 
730 	return error;
731 }
732 
733 /*
734  * sys_mlock: memory lock
735  */
736 
737 int
738 sys_mlock(struct lwp *l, const struct sys_mlock_args *uap, register_t *retval)
739 {
740 	/* {
741 		syscallarg(const void *) addr;
742 		syscallarg(size_t) len;
743 	} */
744 	struct proc *p = l->l_proc;
745 	vaddr_t addr;
746 	vsize_t size, pageoff;
747 	int error;
748 
749 	/*
750 	 * extract syscall args from uap
751 	 */
752 
753 	addr = (vaddr_t)SCARG(uap, addr);
754 	size = (vsize_t)SCARG(uap, len);
755 
756 	/*
757 	 * align the address to a page boundary and adjust the size accordingly
758 	 */
759 
760 	pageoff = (addr & PAGE_MASK);
761 	addr -= pageoff;
762 	size += pageoff;
763 	size = (vsize_t)round_page(size);
764 
765 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
766 	if (error)
767 		return ENOMEM;
768 
769 	if (atop(size) + uvmexp.wired > uvmexp.wiredmax)
770 		return EAGAIN;
771 
772 	if (size + ptoa(pmap_wired_count(vm_map_pmap(&p->p_vmspace->vm_map))) >
773 	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur)
774 		return EAGAIN;
775 
776 	error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, false,
777 	    0);
778 	if (error == EFAULT)
779 		error = ENOMEM;
780 	return error;
781 }
782 
783 /*
784  * sys_munlock: unlock wired pages
785  */
786 
787 int
788 sys_munlock(struct lwp *l, const struct sys_munlock_args *uap,
789     register_t *retval)
790 {
791 	/* {
792 		syscallarg(const void *) addr;
793 		syscallarg(size_t) len;
794 	} */
795 	struct proc *p = l->l_proc;
796 	vaddr_t addr;
797 	vsize_t size, pageoff;
798 	int error;
799 
800 	/*
801 	 * extract syscall args from uap
802 	 */
803 
804 	addr = (vaddr_t)SCARG(uap, addr);
805 	size = (vsize_t)SCARG(uap, len);
806 
807 	/*
808 	 * align the address to a page boundary, and adjust the size accordingly
809 	 */
810 
811 	pageoff = (addr & PAGE_MASK);
812 	addr -= pageoff;
813 	size += pageoff;
814 	size = (vsize_t)round_page(size);
815 
816 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
817 	if (error)
818 		return ENOMEM;
819 
820 	error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, true,
821 	    0);
822 	if (error)
823 		return ENOMEM;
824 
825 	return 0;
826 }
827 
828 /*
829  * sys_mlockall: lock all pages mapped into an address space.
830  */
831 
832 int
833 sys_mlockall(struct lwp *l, const struct sys_mlockall_args *uap,
834     register_t *retval)
835 {
836 	/* {
837 		syscallarg(int) flags;
838 	} */
839 	struct proc *p = l->l_proc;
840 	int error, flags;
841 
842 	flags = SCARG(uap, flags);
843 
844 	if (flags == 0 || (flags & ~(MCL_CURRENT|MCL_FUTURE)) != 0)
845 		return EINVAL;
846 
847 	error = uvm_map_pageable_all(&p->p_vmspace->vm_map, flags,
848 	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
849 	return error;
850 }
851 
852 /*
853  * sys_munlockall: unlock all pages mapped into an address space.
854  */
855 
856 int
857 sys_munlockall(struct lwp *l, const void *v, register_t *retval)
858 {
859 	struct proc *p = l->l_proc;
860 
861 	(void) uvm_map_pageable_all(&p->p_vmspace->vm_map, 0, 0);
862 	return 0;
863 }
864 
865 /*
866  * uvm_mmap: internal version of mmap
867  *
868  * - used by sys_mmap and various framebuffers
869  * - uobj is a struct uvm_object pointer or NULL for MAP_ANON
870  * - caller must page-align the file offset
871  */
872 
873 int
874 uvm_mmap(struct vm_map *map, vaddr_t *addr, vsize_t size, vm_prot_t prot,
875     vm_prot_t maxprot, int flags, int advice, struct uvm_object *uobj,
876     voff_t foff, vsize_t locklimit)
877 {
878 	vaddr_t align = 0;
879 	int error;
880 	uvm_flag_t uvmflag = 0;
881 
882 	/*
883 	 * check params
884 	 */
885 
886 	if (size == 0)
887 		return 0;
888 	if (foff & PAGE_MASK)
889 		return EINVAL;
890 	if ((prot & maxprot) != prot)
891 		return EINVAL;
892 
893 	/*
894 	 * for non-fixed mappings, round off the suggested address.
895 	 * for fixed mappings, check alignment.
896 	 */
897 
898 	if ((flags & MAP_FIXED) == 0) {
899 		*addr = round_page(*addr);
900 	} else {
901 		if (*addr & PAGE_MASK)
902 			return EINVAL;
903 		uvmflag |= UVM_FLAG_FIXED | UVM_FLAG_UNMAP;
904 	}
905 
906 	/*
907 	 * Try to see if any requested alignment can even be attemped.
908 	 * Make sure we can express the alignment (asking for a >= 4GB
909 	 * alignment on an ILP32 architecure make no sense) and the
910 	 * alignment is at least for a page sized quanitiy.  If the
911 	 * request was for a fixed mapping, make sure supplied address
912 	 * adheres to the request alignment.
913 	 */
914 	align = (flags & MAP_ALIGNMENT_MASK) >> MAP_ALIGNMENT_SHIFT;
915 	if (align) {
916 		if (align >= sizeof(vaddr_t) * NBBY)
917 			return EINVAL;
918 		align = 1L << align;
919 		if (align < PAGE_SIZE)
920 			return EINVAL;
921 		if (align >= vm_map_max(map))
922 			return ENOMEM;
923 		if (flags & MAP_FIXED) {
924 			if ((*addr & (align-1)) != 0)
925 				return EINVAL;
926 			align = 0;
927 		}
928 	}
929 
930 	/*
931 	 * check resource limits
932 	 */
933 
934 	if (!VM_MAP_IS_KERNEL(map) &&
935 	    (((rlim_t)curproc->p_vmspace->vm_map.size + (rlim_t)size) >
936 	    curproc->p_rlimit[RLIMIT_AS].rlim_cur))
937 		return ENOMEM;
938 
939 	/*
940 	 * handle anon vs. non-anon mappings.   for non-anon mappings attach
941 	 * to underlying vm object.
942 	 */
943 
944 	if (flags & MAP_ANON) {
945 		KASSERT(uobj == NULL);
946 		foff = UVM_UNKNOWN_OFFSET;
947 		if ((flags & MAP_SHARED) == 0)
948 			/* XXX: defer amap create */
949 			uvmflag |= UVM_FLAG_COPYONW;
950 		else
951 			/* shared: create amap now */
952 			uvmflag |= UVM_FLAG_OVERLAY;
953 
954 	} else {
955 		KASSERT(uobj != NULL);
956 		if ((flags & MAP_SHARED) == 0) {
957 			uvmflag |= UVM_FLAG_COPYONW;
958 		}
959 	}
960 
961 	uvmflag = UVM_MAPFLAG(prot, maxprot,
962 	    (flags & MAP_SHARED) ? UVM_INH_SHARE : UVM_INH_COPY, advice,
963 	    uvmflag);
964 	error = uvm_map(map, addr, size, uobj, foff, align, uvmflag);
965 	if (error) {
966 		if (uobj)
967 			uobj->pgops->pgo_detach(uobj);
968 		return error;
969 	}
970 
971 	/*
972 	 * POSIX 1003.1b -- if our address space was configured
973 	 * to lock all future mappings, wire the one we just made.
974 	 *
975 	 * Also handle the MAP_WIRED flag here.
976 	 */
977 
978 	if (prot == VM_PROT_NONE) {
979 
980 		/*
981 		 * No more work to do in this case.
982 		 */
983 
984 		return 0;
985 	}
986 	if ((flags & MAP_WIRED) != 0 || (map->flags & VM_MAP_WIREFUTURE) != 0) {
987 		vm_map_lock(map);
988 		if (atop(size) + uvmexp.wired > uvmexp.wiredmax ||
989 		    (locklimit != 0 &&
990 		     size + ptoa(pmap_wired_count(vm_map_pmap(map))) >
991 		     locklimit)) {
992 			vm_map_unlock(map);
993 			uvm_unmap(map, *addr, *addr + size);
994 			return ENOMEM;
995 		}
996 
997 		/*
998 		 * uvm_map_pageable() always returns the map unlocked.
999 		 */
1000 
1001 		error = uvm_map_pageable(map, *addr, *addr + size,
1002 		    false, UVM_LK_ENTER);
1003 		if (error) {
1004 			uvm_unmap(map, *addr, *addr + size);
1005 			return error;
1006 		}
1007 		return 0;
1008 	}
1009 	return 0;
1010 }
1011 
1012 vaddr_t
1013 uvm_default_mapaddr(struct proc *p, vaddr_t base, vsize_t sz, int topdown)
1014 {
1015 
1016 	if (topdown)
1017 		return VM_DEFAULT_ADDRESS_TOPDOWN(base, sz);
1018 	else
1019 		return VM_DEFAULT_ADDRESS_BOTTOMUP(base, sz);
1020 }
1021 
1022 int
1023 uvm_mmap_dev(struct proc *p, void **addrp, size_t len, dev_t dev,
1024     off_t off)
1025 {
1026 	struct uvm_object *uobj;
1027 	int error, flags, prot;
1028 
1029 	flags = MAP_SHARED;
1030 	prot = VM_PROT_READ | VM_PROT_WRITE;
1031 	if (*addrp)
1032 		flags |= MAP_FIXED;
1033 	else
1034 		*addrp = (void *)p->p_emul->e_vm_default_addr(p,
1035 		    (vaddr_t)p->p_vmspace->vm_daddr, len,
1036 		    p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN);
1037 
1038 	uobj = udv_attach(dev, prot, off, len);
1039 	if (uobj == NULL)
1040 		return EINVAL;
1041 
1042 	error = uvm_mmap(&p->p_vmspace->vm_map, (vaddr_t *)addrp,
1043 	    (vsize_t)len, prot, prot, flags, UVM_ADV_RANDOM, uobj, off,
1044 	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
1045 	return error;
1046 }
1047 
1048 int
1049 uvm_mmap_anon(struct proc *p, void **addrp, size_t len)
1050 {
1051 	int error, flags, prot;
1052 
1053 	flags = MAP_PRIVATE | MAP_ANON;
1054 	prot = VM_PROT_READ | VM_PROT_WRITE;
1055 	if (*addrp)
1056 		flags |= MAP_FIXED;
1057 	else
1058 		*addrp = (void *)p->p_emul->e_vm_default_addr(p,
1059 		    (vaddr_t)p->p_vmspace->vm_daddr, len,
1060 		    p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN);
1061 
1062 	error = uvm_mmap(&p->p_vmspace->vm_map, (vaddr_t *)addrp,
1063 	    (vsize_t)len, prot, prot, flags, UVM_ADV_NORMAL, NULL, 0,
1064 	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
1065 	return error;
1066 }
1067