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vm.c revision 1.35 
      1 /*	$NetBSD: vm.c,v 1.35 2008/08/04 15:02:16 pooka Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2007 Antti Kantee.  All Rights Reserved.
      5  *
      6  * Development of this software was supported by Google Summer of Code.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     18  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     23  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     27  * SUCH DAMAGE.
     28  */
     29 
     30 /*
     31  * Virtual memory emulation routines.  Contents:
     32  *  + UBC
     33  *  + anon objects & pager
     34  *  + vnode objects & pager
     35  *  + misc support routines
     36  *  + kmem
     37  */
     38 
     39 /*
     40  * XXX: we abuse pg->uanon for the virtual address of the storage
     41  * for each page.  phys_addr would fit the job description better,
     42  * except that it will create unnecessary lossage on some platforms
     43  * due to not being a pointer type.
     44  */
     45 
     46 #include <sys/param.h>
     47 #include <sys/null.h>
     48 #include <sys/vnode.h>
     49 #include <sys/buf.h>
     50 #include <sys/kmem.h>
     51 
     52 #include <machine/pmap.h>
     53 
     54 #include <rump/rumpuser.h>
     55 
     56 #include <uvm/uvm.h>
     57 #include <uvm/uvm_prot.h>
     58 #include <uvm/uvm_readahead.h>
     59 
     60 #include "rump_private.h"
     61 
     62 /* dumdidumdum */
     63 #define len2npages(off, len)						\
     64   (((((len) + PAGE_MASK) & ~(PAGE_MASK)) >> PAGE_SHIFT)			\
     65     + (((off & PAGE_MASK) + (len & PAGE_MASK)) > PAGE_SIZE))
     66 
     67 static int vn_get(struct uvm_object *, voff_t, struct vm_page **,
     68 	int *, int, vm_prot_t, int, int);
     69 static int vn_put(struct uvm_object *, voff_t, voff_t, int);
     70 static int ao_get(struct uvm_object *, voff_t, struct vm_page **,
     71 	int *, int, vm_prot_t, int, int);
     72 static int ao_put(struct uvm_object *, voff_t, voff_t, int);
     73 
     74 const struct uvm_pagerops uvm_vnodeops = {
     75 	.pgo_get = vn_get,
     76 	.pgo_put = vn_put,
     77 };
     78 const struct uvm_pagerops aobj_pager = {
     79 	.pgo_get = ao_get,
     80 	.pgo_put = ao_put,
     81 };
     82 
     83 kmutex_t uvm_pageqlock;
     84 
     85 struct uvmexp uvmexp;
     86 struct uvm uvm;
     87 
     88 struct vmspace rump_vmspace;
     89 struct vm_map rump_vmmap;
     90 const struct rb_tree_ops uvm_page_tree_ops;
     91 
     92 static struct vm_map_kernel kernel_map_store;
     93 struct vm_map *kernel_map = &kernel_map_store.vmk_map;
     94 
     95 /*
     96  * vm pages
     97  */
     98 
     99 /* called with the object locked */
    100 struct vm_page *
    101 rumpvm_makepage(struct uvm_object *uobj, voff_t off)
    102 {
    103 	struct vm_page *pg;
    104 
    105 	pg = kmem_zalloc(sizeof(struct vm_page), KM_SLEEP);
    106 	pg->offset = off;
    107 	pg->uobject = uobj;
    108 
    109 	pg->uanon = (void *)kmem_zalloc(PAGE_SIZE, KM_SLEEP);
    110 	pg->flags = PG_CLEAN|PG_BUSY|PG_FAKE;
    111 
    112 	TAILQ_INSERT_TAIL(&uobj->memq, pg, listq.queue);
    113 
    114 	return pg;
    115 }
    116 
    117 /*
    118  * Release a page.
    119  *
    120  * Called with the vm object locked.
    121  */
    122 void
    123 uvm_pagefree(struct vm_page *pg)
    124 {
    125 	struct uvm_object *uobj = pg->uobject;
    126 
    127 	if (pg->flags & PG_WANTED)
    128 		wakeup(pg);
    129 
    130 	TAILQ_REMOVE(&uobj->memq, pg, listq.queue);
    131 	kmem_free((void *)pg->uanon, PAGE_SIZE);
    132 	kmem_free(pg, sizeof(*pg));
    133 }
    134 
    135 struct rumpva {
    136 	vaddr_t addr;
    137 	struct vm_page *pg;
    138 
    139 	LIST_ENTRY(rumpva) entries;
    140 };
    141 static LIST_HEAD(, rumpva) rvahead = LIST_HEAD_INITIALIZER(rvahead);
    142 static kmutex_t rvamtx;
    143 
    144 void
    145 rumpvm_enterva(vaddr_t addr, struct vm_page *pg)
    146 {
    147 	struct rumpva *rva;
    148 
    149 	rva = kmem_alloc(sizeof(struct rumpva), KM_SLEEP);
    150 	rva->addr = addr;
    151 	rva->pg = pg;
    152 	mutex_enter(&rvamtx);
    153 	LIST_INSERT_HEAD(&rvahead, rva, entries);
    154 	mutex_exit(&rvamtx);
    155 }
    156 
    157 void
    158 rumpvm_flushva()
    159 {
    160 	struct rumpva *rva;
    161 
    162 	mutex_enter(&rvamtx);
    163 	while ((rva = LIST_FIRST(&rvahead)) != NULL) {
    164 		LIST_REMOVE(rva, entries);
    165 		kmem_free(rva, sizeof(*rva));
    166 	}
    167 	mutex_exit(&rvamtx);
    168 }
    169 
    170 /*
    171  * vnode pager
    172  */
    173 
    174 static int
    175 vn_get(struct uvm_object *uobj, voff_t off, struct vm_page **pgs,
    176 	int *npages, int centeridx, vm_prot_t access_type,
    177 	int advice, int flags)
    178 {
    179 	struct vnode *vp = (struct vnode *)uobj;
    180 
    181 	return VOP_GETPAGES(vp, off, pgs, npages, centeridx, access_type,
    182 	    advice, flags);
    183 }
    184 
    185 static int
    186 vn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags)
    187 {
    188 	struct vnode *vp = (struct vnode *)uobj;
    189 
    190 	return VOP_PUTPAGES(vp, offlo, offhi, flags);
    191 }
    192 
    193 /*
    194  * Anon object stuff
    195  */
    196 
    197 static int
    198 ao_get(struct uvm_object *uobj, voff_t off, struct vm_page **pgs,
    199 	int *npages, int centeridx, vm_prot_t access_type,
    200 	int advice, int flags)
    201 {
    202 	struct vm_page *pg;
    203 	int i;
    204 
    205 	if (centeridx)
    206 		panic("%s: centeridx != 0 not supported", __func__);
    207 
    208 	/* loop over pages */
    209 	off = trunc_page(off);
    210 	for (i = 0; i < *npages; i++) {
    211  retrylookup:
    212 		pg = uvm_pagelookup(uobj, off + (i << PAGE_SHIFT));
    213 		if (pg) {
    214 			if (pg->flags & PG_BUSY) {
    215 				pg->flags |= PG_WANTED;
    216 				UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0,
    217 				    "aogetpg", 0);
    218 				goto retrylookup;
    219 			}
    220 			pg->flags |= PG_BUSY;
    221 			pgs[i] = pg;
    222 		} else {
    223 			pg = rumpvm_makepage(uobj, off + (i << PAGE_SHIFT));
    224 			pgs[i] = pg;
    225 		}
    226 	}
    227 	mutex_exit(&uobj->vmobjlock);
    228 
    229 	return 0;
    230 
    231 }
    232 
    233 static int
    234 ao_put(struct uvm_object *uobj, voff_t start, voff_t stop, int flags)
    235 {
    236 	struct vm_page *pg;
    237 
    238 	/* we only free all pages for now */
    239 	if ((flags & PGO_FREE) == 0 || (flags & PGO_ALLPAGES) == 0) {
    240 		mutex_exit(&uobj->vmobjlock);
    241 		return 0;
    242 	}
    243 
    244 	while ((pg = TAILQ_FIRST(&uobj->memq)) != NULL)
    245 		uvm_pagefree(pg);
    246 	mutex_exit(&uobj->vmobjlock);
    247 
    248 	return 0;
    249 }
    250 
    251 struct uvm_object *
    252 uao_create(vsize_t size, int flags)
    253 {
    254 	struct uvm_object *uobj;
    255 
    256 	uobj = kmem_zalloc(sizeof(struct uvm_object), KM_SLEEP);
    257 	uobj->pgops = &aobj_pager;
    258 	TAILQ_INIT(&uobj->memq);
    259 	mutex_init(&uobj->vmobjlock, MUTEX_DEFAULT, IPL_NONE);
    260 
    261 	return uobj;
    262 }
    263 
    264 void
    265 uao_detach(struct uvm_object *uobj)
    266 {
    267 
    268 	mutex_enter(&uobj->vmobjlock);
    269 	ao_put(uobj, 0, 0, PGO_ALLPAGES | PGO_FREE);
    270 	kmem_free(uobj, sizeof(*uobj));
    271 }
    272 
    273 /*
    274  * UBC
    275  */
    276 
    277 struct ubc_window {
    278 	struct uvm_object	*uwin_obj;
    279 	voff_t			uwin_off;
    280 	uint8_t			*uwin_mem;
    281 	size_t			uwin_mapsize;
    282 
    283 	LIST_ENTRY(ubc_window)	uwin_entries;
    284 };
    285 
    286 static LIST_HEAD(, ubc_window) uwinlst = LIST_HEAD_INITIALIZER(uwinlst);
    287 static kmutex_t uwinmtx;
    288 
    289 int
    290 rump_ubc_magic_uiomove(void *va, size_t n, struct uio *uio, int *rvp,
    291 	struct ubc_window *uwinp)
    292 {
    293 	struct vm_page **pgs;
    294 	int npages = len2npages(uio->uio_offset, n);
    295 	size_t allocsize;
    296 	int i, rv;
    297 
    298 	if (uwinp == NULL) {
    299 		mutex_enter(&uwinmtx);
    300 		LIST_FOREACH(uwinp, &uwinlst, uwin_entries)
    301 			if ((uint8_t *)va >= uwinp->uwin_mem
    302 			    && (uint8_t *)va
    303 			      < (uwinp->uwin_mem + uwinp->uwin_mapsize))
    304 				break;
    305 		mutex_exit(&uwinmtx);
    306 		if (uwinp == NULL) {
    307 			KASSERT(rvp != NULL);
    308 			return 0;
    309 		}
    310 	}
    311 
    312 	allocsize = npages * sizeof(pgs);
    313 	pgs = kmem_zalloc(allocsize, KM_SLEEP);
    314 	mutex_enter(&uwinp->uwin_obj->vmobjlock);
    315 	rv = uwinp->uwin_obj->pgops->pgo_get(uwinp->uwin_obj,
    316 	    uwinp->uwin_off + ((uint8_t *)va - uwinp->uwin_mem),
    317 	    pgs, &npages, 0, 0, 0, 0);
    318 	if (rv)
    319 		goto out;
    320 
    321 	for (i = 0; i < npages; i++) {
    322 		size_t xfersize;
    323 		off_t pageoff;
    324 
    325 		pageoff = uio->uio_offset & PAGE_MASK;
    326 		xfersize = MIN(MIN(n, PAGE_SIZE), PAGE_SIZE-pageoff);
    327 		uiomove((uint8_t *)pgs[i]->uanon + pageoff, xfersize, uio);
    328 		if (uio->uio_rw == UIO_WRITE)
    329 			pgs[i]->flags &= ~PG_CLEAN;
    330 		n -= xfersize;
    331 	}
    332 	uvm_page_unbusy(pgs, npages);
    333 
    334  out:
    335 	kmem_free(pgs, allocsize);
    336 	if (rvp)
    337 		*rvp = rv;
    338 	return 1;
    339 }
    340 
    341 static struct ubc_window *
    342 uwin_alloc(struct uvm_object *uobj, voff_t off, vsize_t len)
    343 {
    344 	struct ubc_window *uwinp; /* pronounced: you wimp! */
    345 
    346 	uwinp = kmem_alloc(sizeof(struct ubc_window), KM_SLEEP);
    347 	uwinp->uwin_obj = uobj;
    348 	uwinp->uwin_off = off;
    349 	uwinp->uwin_mapsize = len;
    350 	uwinp->uwin_mem = kmem_alloc(len, KM_SLEEP);
    351 
    352 	return uwinp;
    353 }
    354 
    355 static void
    356 uwin_free(struct ubc_window *uwinp)
    357 {
    358 
    359 	kmem_free(uwinp->uwin_mem, uwinp->uwin_mapsize);
    360 	kmem_free(uwinp, sizeof(struct ubc_window));
    361 }
    362 
    363 void *
    364 ubc_alloc(struct uvm_object *uobj, voff_t offset, vsize_t *lenp, int advice,
    365 	int flags)
    366 {
    367 	struct ubc_window *uwinp;
    368 
    369 	uwinp = uwin_alloc(uobj, offset, *lenp);
    370 	mutex_enter(&uwinmtx);
    371 	LIST_INSERT_HEAD(&uwinlst, uwinp, uwin_entries);
    372 	mutex_exit(&uwinmtx);
    373 
    374 	DPRINTF(("UBC_ALLOC offset 0x%llx, uwin %p, mem %p\n",
    375 	    (unsigned long long)offset, uwinp, uwinp->uwin_mem));
    376 
    377 	return uwinp->uwin_mem;
    378 }
    379 
    380 void
    381 ubc_release(void *va, int flags)
    382 {
    383 	struct ubc_window *uwinp;
    384 
    385 	mutex_enter(&uwinmtx);
    386 	LIST_FOREACH(uwinp, &uwinlst, uwin_entries)
    387 		if ((uint8_t *)va >= uwinp->uwin_mem
    388 		    && (uint8_t *)va < (uwinp->uwin_mem + uwinp->uwin_mapsize))
    389 			break;
    390 	mutex_exit(&uwinmtx);
    391 	if (uwinp == NULL)
    392 		panic("%s: releasing invalid window at %p", __func__, va);
    393 
    394 	LIST_REMOVE(uwinp, uwin_entries);
    395 	uwin_free(uwinp);
    396 }
    397 
    398 int
    399 ubc_uiomove(struct uvm_object *uobj, struct uio *uio, vsize_t todo,
    400 	int advice, int flags)
    401 {
    402 	struct ubc_window *uwinp;
    403 	vsize_t len;
    404 
    405 	while (todo > 0) {
    406 		len = todo;
    407 
    408 		uwinp = uwin_alloc(uobj, uio->uio_offset, len);
    409 		rump_ubc_magic_uiomove(uwinp->uwin_mem, len, uio, NULL, uwinp);
    410 		uwin_free(uwinp);
    411 
    412 		todo -= len;
    413 	}
    414 	return 0;
    415 }
    416 
    417 
    418 /*
    419  * Misc routines
    420  */
    421 
    422 void
    423 rumpvm_init()
    424 {
    425 
    426 	uvmexp.free = 1024*1024; /* XXX */
    427 	uvm.pagedaemon_lwp = NULL; /* doesn't match curlwp */
    428 
    429 	mutex_init(&rvamtx, MUTEX_DEFAULT, 0);
    430 	mutex_init(&uwinmtx, MUTEX_DEFAULT, 0);
    431 	mutex_init(&uvm_pageqlock, MUTEX_DEFAULT, 0);
    432 
    433 	callback_head_init(&kernel_map_store.vmk_reclaim_callback, IPL_VM);
    434 }
    435 
    436 void
    437 uvm_pageactivate(struct vm_page *pg)
    438 {
    439 
    440 	/* nada */
    441 }
    442 
    443 void
    444 uvm_pagewire(struct vm_page *pg)
    445 {
    446 
    447 	/* nada */
    448 }
    449 
    450 void
    451 uvm_pageunwire(struct vm_page *pg)
    452 {
    453 
    454 	/* nada */
    455 }
    456 
    457 vaddr_t
    458 uvm_pagermapin(struct vm_page **pps, int npages, int flags)
    459 {
    460 
    461 	panic("%s: unimplemented", __func__);
    462 }
    463 
    464 /* Called with the vm object locked */
    465 struct vm_page *
    466 uvm_pagelookup(struct uvm_object *uobj, voff_t off)
    467 {
    468 	struct vm_page *pg;
    469 
    470 	TAILQ_FOREACH(pg, &uobj->memq, listq.queue) {
    471 		if (pg->offset == off) {
    472 			return pg;
    473 		}
    474 	}
    475 
    476 	return NULL;
    477 }
    478 
    479 struct vm_page *
    480 uvm_pageratop(vaddr_t va)
    481 {
    482 	struct rumpva *rva;
    483 
    484 	mutex_enter(&rvamtx);
    485 	LIST_FOREACH(rva, &rvahead, entries)
    486 		if (rva->addr == va)
    487 			break;
    488 	mutex_exit(&rvamtx);
    489 
    490 	if (rva == NULL)
    491 		panic("%s: va %llu", __func__, (unsigned long long)va);
    492 
    493 	return rva->pg;
    494 }
    495 
    496 void
    497 uvm_page_unbusy(struct vm_page **pgs, int npgs)
    498 {
    499 	struct vm_page *pg;
    500 	int i;
    501 
    502 	for (i = 0; i < npgs; i++) {
    503 		pg = pgs[i];
    504 		if (pg == NULL)
    505 			continue;
    506 
    507 		KASSERT(pg->flags & PG_BUSY);
    508 		if (pg->flags & PG_WANTED)
    509 			wakeup(pg);
    510 		pg->flags &= ~(PG_WANTED|PG_BUSY);
    511 	}
    512 }
    513 
    514 void
    515 uvm_estimatepageable(int *active, int *inactive)
    516 {
    517 
    518 	/* XXX: guessing game */
    519 	*active = 1024;
    520 	*inactive = 1024;
    521 }
    522 
    523 void
    524 uvm_aio_biodone1(struct buf *bp)
    525 {
    526 
    527 	panic("%s: unimplemented", __func__);
    528 }
    529 
    530 void
    531 uvm_aio_biodone(struct buf *bp)
    532 {
    533 
    534 	uvm_aio_aiodone(bp);
    535 }
    536 
    537 void
    538 uvm_aio_aiodone(struct buf *bp)
    539 {
    540 
    541 	if (((bp->b_flags | bp->b_cflags) & (B_READ | BC_NOCACHE)) == 0 && bioopsp)
    542 		bioopsp->io_pageiodone(bp);
    543 }
    544 
    545 void
    546 uvm_vnp_setsize(struct vnode *vp, voff_t newsize)
    547 {
    548 
    549 	mutex_enter(&vp->v_interlock);
    550 	vp->v_size = vp->v_writesize = newsize;
    551 	mutex_exit(&vp->v_interlock);
    552 }
    553 
    554 void
    555 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize)
    556 {
    557 
    558 	mutex_enter(&vp->v_interlock);
    559 	vp->v_writesize = newsize;
    560 	mutex_exit(&vp->v_interlock);
    561 }
    562 
    563 void
    564 uvm_vnp_zerorange(struct vnode *vp, off_t off, size_t len)
    565 {
    566 	struct uvm_object *uobj = &vp->v_uobj;
    567 	struct vm_page **pgs;
    568 	int maxpages = MIN(32, round_page(len) >> PAGE_SHIFT);
    569 	int rv, npages, i;
    570 
    571 	pgs = kmem_zalloc(maxpages * sizeof(pgs), KM_SLEEP);
    572 	while (len) {
    573 		npages = MIN(maxpages, round_page(len) >> PAGE_SHIFT);
    574 		memset(pgs, 0, npages * sizeof(struct vm_page *));
    575 		mutex_enter(&uobj->vmobjlock);
    576 		rv = uobj->pgops->pgo_get(uobj, off, pgs, &npages, 0, 0, 0, 0);
    577 		KASSERT(npages > 0);
    578 
    579 		for (i = 0; i < npages; i++) {
    580 			uint8_t *start;
    581 			size_t chunkoff, chunklen;
    582 
    583 			chunkoff = off & PAGE_MASK;
    584 			chunklen = MIN(PAGE_SIZE - chunkoff, len);
    585 			start = (uint8_t *)pgs[i]->uanon + chunkoff;
    586 
    587 			memset(start, 0, chunklen);
    588 			pgs[i]->flags &= PG_CLEAN;
    589 
    590 			off += chunklen;
    591 			len -= chunklen;
    592 		}
    593 		uvm_page_unbusy(pgs, npages);
    594 	}
    595 	kmem_free(pgs, maxpages * sizeof(pgs));
    596 
    597 	return;
    598 }
    599 
    600 struct uvm_ractx *
    601 uvm_ra_allocctx()
    602 {
    603 
    604 	return NULL;
    605 }
    606 
    607 void
    608 uvm_ra_freectx(struct uvm_ractx *ra)
    609 {
    610 
    611 	return;
    612 }
    613 
    614 bool
    615 uvn_clean_p(struct uvm_object *uobj)
    616 {
    617 	struct vnode *vp = (void *)uobj;
    618 
    619 	return (vp->v_iflag & VI_ONWORKLST) == 0;
    620 }
    621 
    622 #ifndef RUMP_USE_REAL_KMEM
    623 /*
    624  * Kmem
    625  */
    626 
    627 void *
    628 kmem_alloc(size_t size, km_flag_t kmflag)
    629 {
    630 
    631 	return rumpuser_malloc(size, kmflag == KM_NOSLEEP);
    632 }
    633 
    634 void *
    635 kmem_zalloc(size_t size, km_flag_t kmflag)
    636 {
    637 	void *rv;
    638 
    639 	rv = kmem_alloc(size, kmflag);
    640 	if (rv)
    641 		memset(rv, 0, size);
    642 
    643 	return rv;
    644 }
    645 
    646 void
    647 kmem_free(void *p, size_t size)
    648 {
    649 
    650 	rumpuser_free(p);
    651 }
    652 #endif /* RUMP_USE_REAL_KMEM */
    653 
    654 /*
    655  * UVM km
    656  */
    657 
    658 vaddr_t
    659 uvm_km_alloc(struct vm_map *map, vsize_t size, vsize_t align, uvm_flag_t flags)
    660 {
    661 	void *rv;
    662 
    663 	rv = rumpuser_malloc(size, flags & (UVM_KMF_CANFAIL | UVM_KMF_NOWAIT));
    664 	if (rv && flags & UVM_KMF_ZERO)
    665 		memset(rv, 0, size);
    666 
    667 	return (vaddr_t)rv;
    668 }
    669 
    670 void
    671 uvm_km_free(struct vm_map *map, vaddr_t vaddr, vsize_t size, uvm_flag_t flags)
    672 {
    673 
    674 	rumpuser_free((void *)vaddr);
    675 }
    676 
    677 struct vm_map *
    678 uvm_km_suballoc(struct vm_map *map, vaddr_t *minaddr, vaddr_t *maxaddr,
    679 	vsize_t size, int pageable, bool fixed, struct vm_map_kernel *submap)
    680 {
    681 
    682 	return (struct vm_map *)417416;
    683 }
    684 
    685 void
    686 uvm_pageout_start(int npages)
    687 {
    688 
    689 	uvmexp.paging += npages;
    690 }
    691 
    692 void
    693 uvm_pageout_done(int npages)
    694 {
    695 
    696 	uvmexp.paging -= npages;
    697 
    698 	/*
    699 	 * wake up either of pagedaemon or LWPs waiting for it.
    700 	 */
    701 
    702 	if (uvmexp.free <= uvmexp.reserve_kernel) {
    703 		wakeup(&uvm.pagedaemon);
    704 	} else {
    705 		wakeup(&uvmexp.free);
    706 	}
    707 }
    708 
    709 /*
    710  * Misc
    711  */
    712 struct vm_map_kernel *
    713 vm_map_to_kernel(struct vm_map *map)
    714 {
    715 
    716 	return (struct vm_map_kernel *)map;
    717 }
    718