xref: /netbsd-src/sys/uvm/uvm_mmap.c (revision d909946ca08dceb44d7d0f22ec9488679695d976)
1 /*	$NetBSD: uvm_mmap.c,v 1.162 2016/08/09 12:17:04 kre 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 1.162 2016/08/09 12:17:04 kre 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  * unimplemented VM system calls:
93  */
94 
95 /*
96  * sys_sbrk: sbrk system call.
97  */
98 
99 /* ARGSUSED */
100 int
101 sys_sbrk(struct lwp *l, const struct sys_sbrk_args *uap, register_t *retval)
102 {
103 	/* {
104 		syscallarg(intptr_t) incr;
105 	} */
106 
107 	return ENOSYS;
108 }
109 
110 /*
111  * sys_sstk: sstk system call.
112  */
113 
114 /* ARGSUSED */
115 int
116 sys_sstk(struct lwp *l, const struct sys_sstk_args *uap, register_t *retval)
117 {
118 	/* {
119 		syscallarg(int) incr;
120 	} */
121 
122 	return ENOSYS;
123 }
124 
125 /*
126  * sys_mincore: determine if pages are in core or not.
127  */
128 
129 /* ARGSUSED */
130 int
131 sys_mincore(struct lwp *l, const struct sys_mincore_args *uap,
132     register_t *retval)
133 {
134 	/* {
135 		syscallarg(void *) addr;
136 		syscallarg(size_t) len;
137 		syscallarg(char *) vec;
138 	} */
139 	struct proc *p = l->l_proc;
140 	struct vm_page *pg;
141 	char *vec, pgi;
142 	struct uvm_object *uobj;
143 	struct vm_amap *amap;
144 	struct vm_anon *anon;
145 	struct vm_map_entry *entry;
146 	vaddr_t start, end, lim;
147 	struct vm_map *map;
148 	vsize_t len;
149 	int error = 0, npgs;
150 
151 	map = &p->p_vmspace->vm_map;
152 
153 	start = (vaddr_t)SCARG(uap, addr);
154 	len = SCARG(uap, len);
155 	vec = SCARG(uap, vec);
156 
157 	if (start & PAGE_MASK)
158 		return EINVAL;
159 	len = round_page(len);
160 	end = start + len;
161 	if (end <= start)
162 		return EINVAL;
163 
164 	/*
165 	 * Lock down vec, so our returned status isn't outdated by
166 	 * storing the status byte for a page.
167 	 */
168 
169 	npgs = len >> PAGE_SHIFT;
170 	error = uvm_vslock(p->p_vmspace, vec, npgs, VM_PROT_WRITE);
171 	if (error) {
172 		return error;
173 	}
174 	vm_map_lock_read(map);
175 
176 	if (uvm_map_lookup_entry(map, start, &entry) == false) {
177 		error = ENOMEM;
178 		goto out;
179 	}
180 
181 	for (/* nothing */;
182 	     entry != &map->header && entry->start < end;
183 	     entry = entry->next) {
184 		KASSERT(!UVM_ET_ISSUBMAP(entry));
185 		KASSERT(start >= entry->start);
186 
187 		/* Make sure there are no holes. */
188 		if (entry->end < end &&
189 		     (entry->next == &map->header ||
190 		      entry->next->start > entry->end)) {
191 			error = ENOMEM;
192 			goto out;
193 		}
194 
195 		lim = end < entry->end ? end : entry->end;
196 
197 		/*
198 		 * Special case for objects with no "real" pages.  Those
199 		 * are always considered resident (mapped devices).
200 		 */
201 
202 		if (UVM_ET_ISOBJ(entry)) {
203 			KASSERT(!UVM_OBJ_IS_KERN_OBJECT(entry->object.uvm_obj));
204 			if (UVM_OBJ_IS_DEVICE(entry->object.uvm_obj)) {
205 				for (/* nothing */; start < lim;
206 				     start += PAGE_SIZE, vec++)
207 					subyte(vec, 1);
208 				continue;
209 			}
210 		}
211 
212 		amap = entry->aref.ar_amap;	/* upper layer */
213 		uobj = entry->object.uvm_obj;	/* lower layer */
214 
215 		if (amap != NULL)
216 			amap_lock(amap);
217 		if (uobj != NULL)
218 			mutex_enter(uobj->vmobjlock);
219 
220 		for (/* nothing */; start < lim; start += PAGE_SIZE, vec++) {
221 			pgi = 0;
222 			if (amap != NULL) {
223 				/* Check the upper layer first. */
224 				anon = amap_lookup(&entry->aref,
225 				    start - entry->start);
226 				/* Don't need to lock anon here. */
227 				if (anon != NULL && anon->an_page != NULL) {
228 
229 					/*
230 					 * Anon has the page for this entry
231 					 * offset.
232 					 */
233 
234 					pgi = 1;
235 				}
236 			}
237 			if (uobj != NULL && pgi == 0) {
238 				/* Check the lower layer. */
239 				pg = uvm_pagelookup(uobj,
240 				    entry->offset + (start - entry->start));
241 				if (pg != NULL) {
242 
243 					/*
244 					 * Object has the page for this entry
245 					 * offset.
246 					 */
247 
248 					pgi = 1;
249 				}
250 			}
251 			(void) subyte(vec, pgi);
252 		}
253 		if (uobj != NULL)
254 			mutex_exit(uobj->vmobjlock);
255 		if (amap != NULL)
256 			amap_unlock(amap);
257 	}
258 
259  out:
260 	vm_map_unlock_read(map);
261 	uvm_vsunlock(p->p_vmspace, SCARG(uap, vec), npgs);
262 	return error;
263 }
264 
265 /*
266  * sys_mmap: mmap system call.
267  *
268  * => file offset and address may not be page aligned
269  *    - if MAP_FIXED, offset and address must have remainder mod PAGE_SIZE
270  *    - if address isn't page aligned the mapping starts at trunc_page(addr)
271  *      and the return value is adjusted up by the page offset.
272  */
273 
274 int
275 sys_mmap(struct lwp *l, const struct sys_mmap_args *uap, register_t *retval)
276 {
277 	/* {
278 		syscallarg(void *) addr;
279 		syscallarg(size_t) len;
280 		syscallarg(int) prot;
281 		syscallarg(int) flags;
282 		syscallarg(int) fd;
283 		syscallarg(long) pad;
284 		syscallarg(off_t) pos;
285 	} */
286 	struct proc *p = l->l_proc;
287 	vaddr_t addr;
288 	off_t pos;
289 	vsize_t size, pageoff, newsize;
290 	vm_prot_t prot, maxprot;
291 	int flags, fd, advice;
292 	vaddr_t defaddr;
293 	struct file *fp = NULL;
294 	struct uvm_object *uobj;
295 	int error;
296 #ifdef PAX_ASLR
297 	vaddr_t orig_addr;
298 #endif /* PAX_ASLR */
299 
300 	/*
301 	 * first, extract syscall args from the uap.
302 	 */
303 
304 	addr = (vaddr_t)SCARG(uap, addr);
305 	size = (vsize_t)SCARG(uap, len);
306 	prot = SCARG(uap, prot) & VM_PROT_ALL;
307 	flags = SCARG(uap, flags);
308 	fd = SCARG(uap, fd);
309 	pos = SCARG(uap, pos);
310 
311 #ifdef PAX_ASLR
312 	orig_addr = addr;
313 #endif /* PAX_ASLR */
314 
315 	/*
316 	 * Fixup the old deprecated MAP_COPY into MAP_PRIVATE, and
317 	 * validate the flags.
318 	 */
319 	if (flags & MAP_COPY) {
320 		flags = (flags & ~MAP_COPY) | MAP_PRIVATE;
321 #if defined(COMPAT_10) && defined(__i386__)
322 		/*
323 		 * Ancient kernel on x86 did not obey PROT_EXEC on i386 at least
324 		 * and ld.so did not turn it on. We take care of this on amd64
325 		 * in compat32.
326 		 */
327 		prot |= PROT_EXEC;
328 #endif
329 	}
330 	if ((flags & (MAP_SHARED|MAP_PRIVATE)) == (MAP_SHARED|MAP_PRIVATE))
331 		return EINVAL;
332 
333 	/*
334 	 * align file position and save offset.  adjust size.
335 	 */
336 
337 	pageoff = (pos & PAGE_MASK);
338 	pos    -= pageoff;
339 	newsize = size + pageoff;		/* add offset */
340 	newsize = (vsize_t)round_page(newsize);	/* round up */
341 
342 	if (newsize < size)
343 		return ENOMEM;
344 	size = newsize;
345 
346 	/*
347 	 * now check (MAP_FIXED) or get (!MAP_FIXED) the "addr"
348 	 */
349 	if (flags & MAP_FIXED) {
350 		/* ensure address and file offset are aligned properly */
351 		addr -= pageoff;
352 		if (addr & PAGE_MASK)
353 			return EINVAL;
354 
355 		error = range_test(&p->p_vmspace->vm_map, addr, size, true);
356 		if (error) {
357 			return error;
358 		}
359 	} else if (addr == 0 || !(flags & MAP_TRYFIXED)) {
360 		/*
361 		 * not fixed: make sure we skip over the largest
362 		 * possible heap for non-topdown mapping arrangements.
363 		 * we will refine our guess later (e.g. to account for
364 		 * VAC, etc)
365 		 */
366 
367 		defaddr = p->p_emul->e_vm_default_addr(p,
368 		    (vaddr_t)p->p_vmspace->vm_daddr, size,
369 		    p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN);
370 
371 		if (addr == 0 || !(p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN))
372 			addr = MAX(addr, defaddr);
373 		else
374 			addr = MIN(addr, defaddr);
375 	}
376 
377 	/*
378 	 * check for file mappings (i.e. not anonymous) and verify file.
379 	 */
380 
381 	advice = UVM_ADV_NORMAL;
382 	if ((flags & MAP_ANON) == 0) {
383 		if ((fp = fd_getfile(fd)) == NULL)
384 			return EBADF;
385 
386 		if (fp->f_ops->fo_mmap == NULL) {
387 			error = ENODEV;
388 			goto out;
389 		}
390 		error = (*fp->f_ops->fo_mmap)(fp, &pos, size, prot, &flags,
391 		    &advice, &uobj, &maxprot);
392 		if (error) {
393 			goto out;
394 		}
395 		if (uobj == NULL) {
396 			flags |= MAP_ANON;
397 			fd_putfile(fd);
398 			fp = NULL;
399 			goto is_anon;
400 		}
401 	} else {		/* MAP_ANON case */
402 		/*
403 		 * XXX What do we do about (MAP_SHARED|MAP_PRIVATE) == 0?
404 		 */
405 		if (fd != -1)
406 			return EINVAL;
407 
408  is_anon:		/* label for SunOS style /dev/zero */
409 		uobj = NULL;
410 		maxprot = VM_PROT_ALL;
411 		pos = 0;
412 	}
413 
414 	PAX_MPROTECT_ADJUST(l, &prot, &maxprot);
415 
416 	pax_aslr_mmap(l, &addr, orig_addr, flags);
417 
418 	/*
419 	 * now let kernel internal function uvm_mmap do the work.
420 	 */
421 
422 	error = uvm_mmap(&p->p_vmspace->vm_map, &addr, size, prot, maxprot,
423 	    flags, advice, uobj, pos, p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
424 
425 	/* remember to add offset */
426 	*retval = (register_t)(addr + pageoff);
427 
428  out:
429 	if (fp != NULL)
430 		fd_putfile(fd);
431 
432 	return error;
433 }
434 
435 /*
436  * sys___msync13: the msync system call (a front-end for flush)
437  */
438 
439 int
440 sys___msync13(struct lwp *l, const struct sys___msync13_args *uap,
441     register_t *retval)
442 {
443 	/* {
444 		syscallarg(void *) addr;
445 		syscallarg(size_t) len;
446 		syscallarg(int) flags;
447 	} */
448 	struct proc *p = l->l_proc;
449 	vaddr_t addr;
450 	vsize_t size, pageoff;
451 	struct vm_map *map;
452 	int error, flags, uvmflags;
453 	bool rv;
454 
455 	/*
456 	 * extract syscall args from the uap
457 	 */
458 
459 	addr = (vaddr_t)SCARG(uap, addr);
460 	size = (vsize_t)SCARG(uap, len);
461 	flags = SCARG(uap, flags);
462 
463 	/* sanity check flags */
464 	if ((flags & ~(MS_ASYNC | MS_SYNC | MS_INVALIDATE)) != 0 ||
465 	    (flags & (MS_ASYNC | MS_SYNC | MS_INVALIDATE)) == 0 ||
466 	    (flags & (MS_ASYNC | MS_SYNC)) == (MS_ASYNC | MS_SYNC))
467 		return EINVAL;
468 	if ((flags & (MS_ASYNC | MS_SYNC)) == 0)
469 		flags |= MS_SYNC;
470 
471 	/*
472 	 * align the address to a page boundary and adjust the size accordingly.
473 	 */
474 
475 	pageoff = (addr & PAGE_MASK);
476 	addr -= pageoff;
477 	size += pageoff;
478 	size = (vsize_t)round_page(size);
479 
480 
481 	/*
482 	 * get map
483 	 */
484 	map = &p->p_vmspace->vm_map;
485 
486 	error = range_test(map, addr, size, false);
487 	if (error)
488 		return ENOMEM;
489 
490 	/*
491 	 * XXXCDC: do we really need this semantic?
492 	 *
493 	 * XXX Gak!  If size is zero we are supposed to sync "all modified
494 	 * pages with the region containing addr".  Unfortunately, we
495 	 * don't really keep track of individual mmaps so we approximate
496 	 * by flushing the range of the map entry containing addr.
497 	 * This can be incorrect if the region splits or is coalesced
498 	 * with a neighbor.
499 	 */
500 
501 	if (size == 0) {
502 		struct vm_map_entry *entry;
503 
504 		vm_map_lock_read(map);
505 		rv = uvm_map_lookup_entry(map, addr, &entry);
506 		if (rv == true) {
507 			addr = entry->start;
508 			size = entry->end - entry->start;
509 		}
510 		vm_map_unlock_read(map);
511 		if (rv == false)
512 			return EINVAL;
513 	}
514 
515 	/*
516 	 * translate MS_ flags into PGO_ flags
517 	 */
518 
519 	uvmflags = PGO_CLEANIT;
520 	if (flags & MS_INVALIDATE)
521 		uvmflags |= PGO_FREE;
522 	if (flags & MS_SYNC)
523 		uvmflags |= PGO_SYNCIO;
524 
525 	error = uvm_map_clean(map, addr, addr+size, uvmflags);
526 	return error;
527 }
528 
529 /*
530  * sys_munmap: unmap a users memory
531  */
532 
533 int
534 sys_munmap(struct lwp *l, const struct sys_munmap_args *uap, register_t *retval)
535 {
536 	/* {
537 		syscallarg(void *) addr;
538 		syscallarg(size_t) len;
539 	} */
540 	struct proc *p = l->l_proc;
541 	vaddr_t addr;
542 	vsize_t size, pageoff;
543 	struct vm_map *map;
544 	struct vm_map_entry *dead_entries;
545 	int error;
546 
547 	/*
548 	 * get syscall args.
549 	 */
550 
551 	addr = (vaddr_t)SCARG(uap, addr);
552 	size = (vsize_t)SCARG(uap, len);
553 
554 	/*
555 	 * align the address to a page boundary and adjust the size accordingly.
556 	 */
557 
558 	pageoff = (addr & PAGE_MASK);
559 	addr -= pageoff;
560 	size += pageoff;
561 	size = (vsize_t)round_page(size);
562 
563 	if (size == 0)
564 		return 0;
565 
566 	map = &p->p_vmspace->vm_map;
567 
568 	error = range_test(map, addr, size, false);
569 	if (error)
570 		return EINVAL;
571 
572 	vm_map_lock(map);
573 #if 0
574 	/*
575 	 * interesting system call semantic: make sure entire range is
576 	 * allocated before allowing an unmap.
577 	 */
578 	if (!uvm_map_checkprot(map, addr, addr + size, VM_PROT_NONE)) {
579 		vm_map_unlock(map);
580 		return EINVAL;
581 	}
582 #endif
583 	uvm_unmap_remove(map, addr, addr + size, &dead_entries, 0);
584 	vm_map_unlock(map);
585 	if (dead_entries != NULL)
586 		uvm_unmap_detach(dead_entries, 0);
587 	return 0;
588 }
589 
590 /*
591  * sys_mprotect: the mprotect system call
592  */
593 
594 int
595 sys_mprotect(struct lwp *l, const struct sys_mprotect_args *uap,
596     register_t *retval)
597 {
598 	/* {
599 		syscallarg(void *) addr;
600 		syscallarg(size_t) len;
601 		syscallarg(int) prot;
602 	} */
603 	struct proc *p = l->l_proc;
604 	vaddr_t addr;
605 	vsize_t size, pageoff;
606 	vm_prot_t prot;
607 	int error;
608 
609 	/*
610 	 * extract syscall args from uap
611 	 */
612 
613 	addr = (vaddr_t)SCARG(uap, addr);
614 	size = (vsize_t)SCARG(uap, len);
615 	prot = SCARG(uap, prot) & VM_PROT_ALL;
616 
617 	/*
618 	 * align the address to a page boundary and adjust the size accordingly.
619 	 */
620 
621 	pageoff = (addr & PAGE_MASK);
622 	addr -= pageoff;
623 	size += pageoff;
624 	size = round_page(size);
625 
626 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
627 	if (error)
628 		return EINVAL;
629 
630 	error = uvm_map_protect(&p->p_vmspace->vm_map, addr, addr + size, prot,
631 				false);
632 	return error;
633 }
634 
635 /*
636  * sys_minherit: the minherit system call
637  */
638 
639 int
640 sys_minherit(struct lwp *l, const struct sys_minherit_args *uap,
641    register_t *retval)
642 {
643 	/* {
644 		syscallarg(void *) addr;
645 		syscallarg(int) len;
646 		syscallarg(int) inherit;
647 	} */
648 	struct proc *p = l->l_proc;
649 	vaddr_t addr;
650 	vsize_t size, pageoff;
651 	vm_inherit_t inherit;
652 	int error;
653 
654 	addr = (vaddr_t)SCARG(uap, addr);
655 	size = (vsize_t)SCARG(uap, len);
656 	inherit = SCARG(uap, inherit);
657 
658 	/*
659 	 * align the address to a page boundary and adjust the size accordingly.
660 	 */
661 
662 	pageoff = (addr & PAGE_MASK);
663 	addr -= pageoff;
664 	size += pageoff;
665 	size = (vsize_t)round_page(size);
666 
667 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
668 	if (error)
669 		return EINVAL;
670 
671 	error = uvm_map_inherit(&p->p_vmspace->vm_map, addr, addr + size,
672 	    inherit);
673 	return error;
674 }
675 
676 /*
677  * sys_madvise: give advice about memory usage.
678  */
679 
680 /* ARGSUSED */
681 int
682 sys_madvise(struct lwp *l, const struct sys_madvise_args *uap,
683    register_t *retval)
684 {
685 	/* {
686 		syscallarg(void *) addr;
687 		syscallarg(size_t) len;
688 		syscallarg(int) behav;
689 	} */
690 	struct proc *p = l->l_proc;
691 	vaddr_t addr;
692 	vsize_t size, pageoff;
693 	int advice, error;
694 
695 	addr = (vaddr_t)SCARG(uap, addr);
696 	size = (vsize_t)SCARG(uap, len);
697 	advice = SCARG(uap, behav);
698 
699 	/*
700 	 * align the address to a page boundary, and adjust the size accordingly
701 	 */
702 
703 	pageoff = (addr & PAGE_MASK);
704 	addr -= pageoff;
705 	size += pageoff;
706 	size = (vsize_t)round_page(size);
707 
708 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
709 	if (error)
710 		return EINVAL;
711 
712 	switch (advice) {
713 	case MADV_NORMAL:
714 	case MADV_RANDOM:
715 	case MADV_SEQUENTIAL:
716 		error = uvm_map_advice(&p->p_vmspace->vm_map, addr, addr + size,
717 		    advice);
718 		break;
719 
720 	case MADV_WILLNEED:
721 
722 		/*
723 		 * Activate all these pages, pre-faulting them in if
724 		 * necessary.
725 		 */
726 		error = uvm_map_willneed(&p->p_vmspace->vm_map,
727 		    addr, addr + size);
728 		break;
729 
730 	case MADV_DONTNEED:
731 
732 		/*
733 		 * Deactivate all these pages.  We don't need them
734 		 * any more.  We don't, however, toss the data in
735 		 * the pages.
736 		 */
737 
738 		error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size,
739 		    PGO_DEACTIVATE);
740 		break;
741 
742 	case MADV_FREE:
743 
744 		/*
745 		 * These pages contain no valid data, and may be
746 		 * garbage-collected.  Toss all resources, including
747 		 * any swap space in use.
748 		 */
749 
750 		error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size,
751 		    PGO_FREE);
752 		break;
753 
754 	case MADV_SPACEAVAIL:
755 
756 		/*
757 		 * XXXMRG What is this?  I think it's:
758 		 *
759 		 *	Ensure that we have allocated backing-store
760 		 *	for these pages.
761 		 *
762 		 * This is going to require changes to the page daemon,
763 		 * as it will free swap space allocated to pages in core.
764 		 * There's also what to do for device/file/anonymous memory.
765 		 */
766 
767 		return EINVAL;
768 
769 	default:
770 		return EINVAL;
771 	}
772 
773 	return error;
774 }
775 
776 /*
777  * sys_mlock: memory lock
778  */
779 
780 int
781 sys_mlock(struct lwp *l, const struct sys_mlock_args *uap, register_t *retval)
782 {
783 	/* {
784 		syscallarg(const void *) addr;
785 		syscallarg(size_t) len;
786 	} */
787 	struct proc *p = l->l_proc;
788 	vaddr_t addr;
789 	vsize_t size, pageoff;
790 	int error;
791 
792 	/*
793 	 * extract syscall args from uap
794 	 */
795 
796 	addr = (vaddr_t)SCARG(uap, addr);
797 	size = (vsize_t)SCARG(uap, len);
798 
799 	/*
800 	 * align the address to a page boundary and adjust the size accordingly
801 	 */
802 
803 	pageoff = (addr & PAGE_MASK);
804 	addr -= pageoff;
805 	size += pageoff;
806 	size = (vsize_t)round_page(size);
807 
808 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
809 	if (error)
810 		return ENOMEM;
811 
812 	if (atop(size) + uvmexp.wired > uvmexp.wiredmax)
813 		return EAGAIN;
814 
815 	if (size + ptoa(pmap_wired_count(vm_map_pmap(&p->p_vmspace->vm_map))) >
816 	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur)
817 		return EAGAIN;
818 
819 	error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, false,
820 	    0);
821 	if (error == EFAULT)
822 		error = ENOMEM;
823 	return error;
824 }
825 
826 /*
827  * sys_munlock: unlock wired pages
828  */
829 
830 int
831 sys_munlock(struct lwp *l, const struct sys_munlock_args *uap,
832     register_t *retval)
833 {
834 	/* {
835 		syscallarg(const void *) addr;
836 		syscallarg(size_t) len;
837 	} */
838 	struct proc *p = l->l_proc;
839 	vaddr_t addr;
840 	vsize_t size, pageoff;
841 	int error;
842 
843 	/*
844 	 * extract syscall args from uap
845 	 */
846 
847 	addr = (vaddr_t)SCARG(uap, addr);
848 	size = (vsize_t)SCARG(uap, len);
849 
850 	/*
851 	 * align the address to a page boundary, and adjust the size accordingly
852 	 */
853 
854 	pageoff = (addr & PAGE_MASK);
855 	addr -= pageoff;
856 	size += pageoff;
857 	size = (vsize_t)round_page(size);
858 
859 	error = range_test(&p->p_vmspace->vm_map, addr, size, false);
860 	if (error)
861 		return ENOMEM;
862 
863 	error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, true,
864 	    0);
865 	if (error)
866 		return ENOMEM;
867 
868 	return 0;
869 }
870 
871 /*
872  * sys_mlockall: lock all pages mapped into an address space.
873  */
874 
875 int
876 sys_mlockall(struct lwp *l, const struct sys_mlockall_args *uap,
877     register_t *retval)
878 {
879 	/* {
880 		syscallarg(int) flags;
881 	} */
882 	struct proc *p = l->l_proc;
883 	int error, flags;
884 
885 	flags = SCARG(uap, flags);
886 
887 	if (flags == 0 || (flags & ~(MCL_CURRENT|MCL_FUTURE)) != 0)
888 		return EINVAL;
889 
890 	error = uvm_map_pageable_all(&p->p_vmspace->vm_map, flags,
891 	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
892 	return error;
893 }
894 
895 /*
896  * sys_munlockall: unlock all pages mapped into an address space.
897  */
898 
899 int
900 sys_munlockall(struct lwp *l, const void *v, register_t *retval)
901 {
902 	struct proc *p = l->l_proc;
903 
904 	(void) uvm_map_pageable_all(&p->p_vmspace->vm_map, 0, 0);
905 	return 0;
906 }
907 
908 /*
909  * uvm_mmap: internal version of mmap
910  *
911  * - used by sys_mmap and various framebuffers
912  * - uobj is a struct uvm_object pointer or NULL for MAP_ANON
913  * - caller must page-align the file offset
914  */
915 
916 int
917 uvm_mmap(struct vm_map *map, vaddr_t *addr, vsize_t size, vm_prot_t prot,
918     vm_prot_t maxprot, int flags, int advice, struct uvm_object *uobj,
919     voff_t foff, vsize_t locklimit)
920 {
921 	vaddr_t align = 0;
922 	int error;
923 	uvm_flag_t uvmflag = 0;
924 
925 	/*
926 	 * check params
927 	 */
928 
929 	if (size == 0)
930 		return 0;
931 	if (foff & PAGE_MASK)
932 		return EINVAL;
933 	if ((prot & maxprot) != prot)
934 		return EINVAL;
935 
936 	/*
937 	 * for non-fixed mappings, round off the suggested address.
938 	 * for fixed mappings, check alignment and zap old mappings.
939 	 */
940 
941 	if ((flags & MAP_FIXED) == 0) {
942 		*addr = round_page(*addr);
943 	} else {
944 		if (*addr & PAGE_MASK)
945 			return EINVAL;
946 		uvmflag |= UVM_FLAG_FIXED;
947 		(void) uvm_unmap(map, *addr, *addr + size);
948 	}
949 
950 	/*
951 	 * Try to see if any requested alignment can even be attemped.
952 	 * Make sure we can express the alignment (asking for a >= 4GB
953 	 * alignment on an ILP32 architecure make no sense) and the
954 	 * alignment is at least for a page sized quanitiy.  If the
955 	 * request was for a fixed mapping, make sure supplied address
956 	 * adheres to the request alignment.
957 	 */
958 	align = (flags & MAP_ALIGNMENT_MASK) >> MAP_ALIGNMENT_SHIFT;
959 	if (align) {
960 		if (align >= sizeof(vaddr_t) * NBBY)
961 			return EINVAL;
962 		align = 1L << align;
963 		if (align < PAGE_SIZE)
964 			return EINVAL;
965 		if (align >= vm_map_max(map))
966 			return ENOMEM;
967 		if (flags & MAP_FIXED) {
968 			if ((*addr & (align-1)) != 0)
969 				return EINVAL;
970 			align = 0;
971 		}
972 	}
973 
974 	/*
975 	 * check resource limits
976 	 */
977 
978 	if (!VM_MAP_IS_KERNEL(map) &&
979 	    (((rlim_t)curproc->p_vmspace->vm_map.size + (rlim_t)size) >
980 	    curproc->p_rlimit[RLIMIT_AS].rlim_cur))
981 		return ENOMEM;
982 
983 	/*
984 	 * handle anon vs. non-anon mappings.   for non-anon mappings attach
985 	 * to underlying vm object.
986 	 */
987 
988 	if (flags & MAP_ANON) {
989 		KASSERT(uobj == NULL);
990 		foff = UVM_UNKNOWN_OFFSET;
991 		if ((flags & MAP_SHARED) == 0)
992 			/* XXX: defer amap create */
993 			uvmflag |= UVM_FLAG_COPYONW;
994 		else
995 			/* shared: create amap now */
996 			uvmflag |= UVM_FLAG_OVERLAY;
997 
998 	} else {
999 		KASSERT(uobj != NULL);
1000 		if ((flags & MAP_SHARED) == 0) {
1001 			uvmflag |= UVM_FLAG_COPYONW;
1002 		}
1003 	}
1004 
1005 	uvmflag = UVM_MAPFLAG(prot, maxprot,
1006 	    (flags & MAP_SHARED) ? UVM_INH_SHARE : UVM_INH_COPY, advice,
1007 	    uvmflag);
1008 	error = uvm_map(map, addr, size, uobj, foff, align, uvmflag);
1009 	if (error) {
1010 		if (uobj)
1011 			uobj->pgops->pgo_detach(uobj);
1012 		return error;
1013 	}
1014 
1015 	/*
1016 	 * POSIX 1003.1b -- if our address space was configured
1017 	 * to lock all future mappings, wire the one we just made.
1018 	 *
1019 	 * Also handle the MAP_WIRED flag here.
1020 	 */
1021 
1022 	if (prot == VM_PROT_NONE) {
1023 
1024 		/*
1025 		 * No more work to do in this case.
1026 		 */
1027 
1028 		return 0;
1029 	}
1030 	if ((flags & MAP_WIRED) != 0 || (map->flags & VM_MAP_WIREFUTURE) != 0) {
1031 		vm_map_lock(map);
1032 		if (atop(size) + uvmexp.wired > uvmexp.wiredmax ||
1033 		    (locklimit != 0 &&
1034 		     size + ptoa(pmap_wired_count(vm_map_pmap(map))) >
1035 		     locklimit)) {
1036 			vm_map_unlock(map);
1037 			uvm_unmap(map, *addr, *addr + size);
1038 			return ENOMEM;
1039 		}
1040 
1041 		/*
1042 		 * uvm_map_pageable() always returns the map unlocked.
1043 		 */
1044 
1045 		error = uvm_map_pageable(map, *addr, *addr + size,
1046 		    false, UVM_LK_ENTER);
1047 		if (error) {
1048 			uvm_unmap(map, *addr, *addr + size);
1049 			return error;
1050 		}
1051 		return 0;
1052 	}
1053 	return 0;
1054 }
1055 
1056 vaddr_t
1057 uvm_default_mapaddr(struct proc *p, vaddr_t base, vsize_t sz, int topdown)
1058 {
1059 
1060 	if (topdown)
1061 		return VM_DEFAULT_ADDRESS_TOPDOWN(base, sz);
1062 	else
1063 		return VM_DEFAULT_ADDRESS_BOTTOMUP(base, sz);
1064 }
1065 
1066 int
1067 uvm_mmap_dev(struct proc *p, void **addrp, size_t len, dev_t dev,
1068     off_t off)
1069 {
1070 	struct uvm_object *uobj;
1071 	int error, flags, prot;
1072 
1073 	flags = MAP_SHARED;
1074 	prot = VM_PROT_READ | VM_PROT_WRITE;
1075 	if (*addrp)
1076 		flags |= MAP_FIXED;
1077 	else
1078 		*addrp = (void *)p->p_emul->e_vm_default_addr(p,
1079 		    (vaddr_t)p->p_vmspace->vm_daddr, len,
1080 		    p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN);
1081 
1082 	uobj = udv_attach(dev, prot, off, len);
1083 	if (uobj == NULL)
1084 		return EINVAL;
1085 
1086 	error = uvm_mmap(&p->p_vmspace->vm_map, (vaddr_t *)addrp,
1087 	    (vsize_t)len, prot, prot, flags, UVM_ADV_RANDOM, uobj, off,
1088 	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
1089 	return error;
1090 }
1091 
1092 int
1093 uvm_mmap_anon(struct proc *p, void **addrp, size_t len)
1094 {
1095 	int error, flags, prot;
1096 
1097 	flags = MAP_PRIVATE | MAP_ANON;
1098 	prot = VM_PROT_READ | VM_PROT_WRITE;
1099 	if (*addrp)
1100 		flags |= MAP_FIXED;
1101 	else
1102 		*addrp = (void *)p->p_emul->e_vm_default_addr(p,
1103 		    (vaddr_t)p->p_vmspace->vm_daddr, len,
1104 		    p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN);
1105 
1106 	error = uvm_mmap(&p->p_vmspace->vm_map, (vaddr_t *)addrp,
1107 	    (vsize_t)len, prot, prot, flags, UVM_ADV_NORMAL, NULL, 0,
1108 	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
1109 	return error;
1110 }
1111