Annotation of src/sys/uvm/uvm_fault.c, Revision 1.112.2.2
1.112.2.2! yamt 1: /* $NetBSD: uvm_fault.c,v 1.112.2.1 2006/10/22 06:07:52 yamt Exp $ */
1.1 mrg 2:
3: /*
4: *
5: * Copyright (c) 1997 Charles D. Cranor and Washington University.
6: * All rights reserved.
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: * 3. All advertising materials mentioning features or use of this software
17: * must display the following acknowledgement:
18: * This product includes software developed by Charles D. Cranor and
19: * Washington University.
20: * 4. The name of the author may not be used to endorse or promote products
21: * derived from this software without specific prior written permission.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.4 mrg 33: *
34: * from: Id: uvm_fault.c,v 1.1.2.23 1998/02/06 05:29:05 chs Exp
1.1 mrg 35: */
36:
37: /*
38: * uvm_fault.c: fault handler
39: */
1.71 lukem 40:
41: #include <sys/cdefs.h>
1.112.2.2! yamt 42: __KERNEL_RCSID(0, "$NetBSD: uvm_fault.c,v 1.112.2.1 2006/10/22 06:07:52 yamt Exp $");
1.71 lukem 43:
44: #include "opt_uvmhist.h"
1.1 mrg 45:
46: #include <sys/param.h>
47: #include <sys/systm.h>
48: #include <sys/kernel.h>
49: #include <sys/proc.h>
50: #include <sys/malloc.h>
51: #include <sys/mman.h>
1.9 chuck 52: #include <sys/user.h>
1.1 mrg 53:
54: #include <uvm/uvm.h>
55:
56: /*
57: *
58: * a word on page faults:
59: *
60: * types of page faults we handle:
61: *
62: * CASE 1: upper layer faults CASE 2: lower layer faults
63: *
64: * CASE 1A CASE 1B CASE 2A CASE 2B
65: * read/write1 write>1 read/write +-cow_write/zero
1.63 chs 66: * | | | |
1.1 mrg 67: * +--|--+ +--|--+ +-----+ + | + | +-----+
68: * amap | V | | ----------->new| | | | ^ |
69: * +-----+ +-----+ +-----+ + | + | +--|--+
70: * | | |
71: * +-----+ +-----+ +--|--+ | +--|--+
72: * uobj | d/c | | d/c | | V | +----| |
73: * +-----+ +-----+ +-----+ +-----+
74: *
75: * d/c = don't care
1.63 chs 76: *
1.1 mrg 77: * case [0]: layerless fault
78: * no amap or uobj is present. this is an error.
79: *
80: * case [1]: upper layer fault [anon active]
81: * 1A: [read] or [write with anon->an_ref == 1]
82: * I/O takes place in top level anon and uobj is not touched.
83: * 1B: [write with anon->an_ref > 1]
84: * new anon is alloc'd and data is copied off ["COW"]
85: *
86: * case [2]: lower layer fault [uobj]
87: * 2A: [read on non-NULL uobj] or [write to non-copy_on_write area]
88: * I/O takes place directly in object.
89: * 2B: [write to copy_on_write] or [read on NULL uobj]
1.63 chs 90: * data is "promoted" from uobj to a new anon.
1.1 mrg 91: * if uobj is null, then we zero fill.
92: *
93: * we follow the standard UVM locking protocol ordering:
94: *
1.63 chs 95: * MAPS => AMAP => UOBJ => ANON => PAGE QUEUES (PQ)
1.1 mrg 96: * we hold a PG_BUSY page if we unlock for I/O
97: *
98: *
99: * the code is structured as follows:
1.63 chs 100: *
1.1 mrg 101: * - init the "IN" params in the ufi structure
102: * ReFault:
103: * - do lookups [locks maps], check protection, handle needs_copy
104: * - check for case 0 fault (error)
105: * - establish "range" of fault
106: * - if we have an amap lock it and extract the anons
107: * - if sequential advice deactivate pages behind us
108: * - at the same time check pmap for unmapped areas and anon for pages
109: * that we could map in (and do map it if found)
110: * - check object for resident pages that we could map in
111: * - if (case 2) goto Case2
112: * - >>> handle case 1
113: * - ensure source anon is resident in RAM
114: * - if case 1B alloc new anon and copy from source
115: * - map the correct page in
116: * Case2:
117: * - >>> handle case 2
118: * - ensure source page is resident (if uobj)
119: * - if case 2B alloc new anon and copy from source (could be zero
120: * fill if uobj == NULL)
121: * - map the correct page in
122: * - done!
123: *
124: * note on paging:
125: * if we have to do I/O we place a PG_BUSY page in the correct object,
126: * unlock everything, and do the I/O. when I/O is done we must reverify
127: * the state of the world before assuming that our data structures are
128: * valid. [because mappings could change while the map is unlocked]
129: *
130: * alternative 1: unbusy the page in question and restart the page fault
131: * from the top (ReFault). this is easy but does not take advantage
1.63 chs 132: * of the information that we already have from our previous lookup,
1.1 mrg 133: * although it is possible that the "hints" in the vm_map will help here.
134: *
135: * alternative 2: the system already keeps track of a "version" number of
136: * a map. [i.e. every time you write-lock a map (e.g. to change a
137: * mapping) you bump the version number up by one...] so, we can save
138: * the version number of the map before we release the lock and start I/O.
139: * then when I/O is done we can relock and check the version numbers
140: * to see if anything changed. this might save us some over 1 because
141: * we don't have to unbusy the page and may be less compares(?).
142: *
143: * alternative 3: put in backpointers or a way to "hold" part of a map
144: * in place while I/O is in progress. this could be complex to
145: * implement (especially with structures like amap that can be referenced
146: * by multiple map entries, and figuring out what should wait could be
147: * complex as well...).
148: *
149: * given that we are not currently multiprocessor or multithreaded we might
150: * as well choose alternative 2 now. maybe alternative 3 would be useful
151: * in the future. XXX keep in mind for future consideration//rechecking.
152: */
153:
154: /*
155: * local data structures
156: */
157:
158: struct uvm_advice {
1.7 mrg 159: int advice;
160: int nback;
161: int nforw;
1.1 mrg 162: };
163:
164: /*
165: * page range array:
1.63 chs 166: * note: index in array must match "advice" value
1.1 mrg 167: * XXX: borrowed numbers from freebsd. do they work well for us?
168: */
169:
1.95 thorpej 170: static const struct uvm_advice uvmadvice[] = {
1.7 mrg 171: { MADV_NORMAL, 3, 4 },
172: { MADV_RANDOM, 0, 0 },
173: { MADV_SEQUENTIAL, 8, 7},
1.1 mrg 174: };
175:
1.69 chs 176: #define UVM_MAXRANGE 16 /* must be MAX() of nback+nforw+1 */
1.1 mrg 177:
178: /*
179: * private prototypes
180: */
181:
182: /*
183: * inline functions
184: */
185:
186: /*
187: * uvmfault_anonflush: try and deactivate pages in specified anons
188: *
189: * => does not have to deactivate page if it is busy
190: */
191:
1.103 perry 192: static inline void
1.95 thorpej 193: uvmfault_anonflush(struct vm_anon **anons, int n)
1.1 mrg 194: {
1.7 mrg 195: int lcv;
196: struct vm_page *pg;
1.63 chs 197:
1.7 mrg 198: for (lcv = 0 ; lcv < n ; lcv++) {
199: if (anons[lcv] == NULL)
200: continue;
201: simple_lock(&anons[lcv]->an_lock);
1.94 yamt 202: pg = anons[lcv]->an_page;
1.7 mrg 203: if (pg && (pg->flags & PG_BUSY) == 0 && pg->loan_count == 0) {
204: uvm_lock_pageq();
205: if (pg->wire_count == 0) {
1.55 thorpej 206: pmap_clear_reference(pg);
1.7 mrg 207: uvm_pagedeactivate(pg);
208: }
209: uvm_unlock_pageq();
210: }
211: simple_unlock(&anons[lcv]->an_lock);
212: }
1.1 mrg 213: }
214:
215: /*
216: * normal functions
217: */
218:
219: /*
220: * uvmfault_amapcopy: clear "needs_copy" in a map.
221: *
222: * => called with VM data structures unlocked (usually, see below)
223: * => we get a write lock on the maps and clear needs_copy for a VA
224: * => if we are out of RAM we sleep (waiting for more)
225: */
226:
1.7 mrg 227: static void
1.95 thorpej 228: uvmfault_amapcopy(struct uvm_faultinfo *ufi)
1.1 mrg 229: {
1.69 chs 230: for (;;) {
1.1 mrg 231:
1.7 mrg 232: /*
233: * no mapping? give up.
234: */
1.1 mrg 235:
1.7 mrg 236: if (uvmfault_lookup(ufi, TRUE) == FALSE)
237: return;
1.1 mrg 238:
1.7 mrg 239: /*
240: * copy if needed.
241: */
1.1 mrg 242:
1.7 mrg 243: if (UVM_ET_ISNEEDSCOPY(ufi->entry))
1.108 yamt 244: amap_copy(ufi->map, ufi->entry, AMAP_COPY_NOWAIT,
1.13 chuck 245: ufi->orig_rvaddr, ufi->orig_rvaddr + 1);
1.1 mrg 246:
1.7 mrg 247: /*
248: * didn't work? must be out of RAM. unlock and sleep.
249: */
250:
251: if (UVM_ET_ISNEEDSCOPY(ufi->entry)) {
252: uvmfault_unlockmaps(ufi, TRUE);
253: uvm_wait("fltamapcopy");
254: continue;
255: }
256:
257: /*
258: * got it! unlock and return.
259: */
1.63 chs 260:
1.7 mrg 261: uvmfault_unlockmaps(ufi, TRUE);
262: return;
263: }
264: /*NOTREACHED*/
1.1 mrg 265: }
266:
267: /*
268: * uvmfault_anonget: get data in an anon into a non-busy, non-released
269: * page in that anon.
270: *
271: * => maps, amap, and anon locked by caller.
1.57 chs 272: * => if we fail (result != 0) we unlock everything.
1.1 mrg 273: * => if we are successful, we return with everything still locked.
274: * => we don't move the page on the queues [gets moved later]
275: * => if we allocate a new page [we_own], it gets put on the queues.
276: * either way, the result is that the page is on the queues at return time
277: * => for pages which are on loan from a uvm_object (and thus are not
278: * owned by the anon): if successful, we return with the owning object
279: * locked. the caller must unlock this object when it unlocks everything
280: * else.
281: */
282:
1.47 chs 283: int
1.95 thorpej 284: uvmfault_anonget(struct uvm_faultinfo *ufi, struct vm_amap *amap,
285: struct vm_anon *anon)
1.7 mrg 286: {
287: boolean_t we_own; /* we own anon's page? */
288: boolean_t locked; /* did we relock? */
289: struct vm_page *pg;
1.58 chs 290: int error;
1.7 mrg 291: UVMHIST_FUNC("uvmfault_anonget"); UVMHIST_CALLED(maphist);
292:
1.53 thorpej 293: LOCK_ASSERT(simple_lock_held(&anon->an_lock));
294:
1.58 chs 295: error = 0;
1.9 chuck 296: uvmexp.fltanget++;
297: /* bump rusage counters */
1.94 yamt 298: if (anon->an_page)
1.80 thorpej 299: curproc->p_stats->p_ru.ru_minflt++;
1.9 chuck 300: else
1.80 thorpej 301: curproc->p_stats->p_ru.ru_majflt++;
1.7 mrg 302:
1.63 chs 303: /*
1.7 mrg 304: * loop until we get it, or fail.
305: */
306:
1.69 chs 307: for (;;) {
1.7 mrg 308: we_own = FALSE; /* TRUE if we set PG_BUSY on a page */
1.94 yamt 309: pg = anon->an_page;
1.1 mrg 310:
1.7 mrg 311: /*
312: * if there is a resident page and it is loaned, then anon
313: * may not own it. call out to uvm_anon_lockpage() to ensure
314: * the real owner of the page has been identified and locked.
315: */
316:
317: if (pg && pg->loan_count)
1.13 chuck 318: pg = uvm_anon_lockloanpg(anon);
1.7 mrg 319:
320: /*
321: * page there? make sure it is not busy/released.
322: */
323:
324: if (pg) {
325:
326: /*
327: * at this point, if the page has a uobject [meaning
328: * we have it on loan], then that uobject is locked
329: * by us! if the page is busy, we drop all the
330: * locks (including uobject) and try again.
331: */
332:
1.69 chs 333: if ((pg->flags & PG_BUSY) == 0) {
1.7 mrg 334: UVMHIST_LOG(maphist, "<- OK",0,0,0,0);
1.57 chs 335: return (0);
1.7 mrg 336: }
337: pg->flags |= PG_WANTED;
338: uvmexp.fltpgwait++;
339:
340: /*
341: * the last unlock must be an atomic unlock+wait on
342: * the owner of page
343: */
1.69 chs 344:
1.7 mrg 345: if (pg->uobject) { /* owner is uobject ? */
346: uvmfault_unlockall(ufi, amap, NULL, anon);
347: UVMHIST_LOG(maphist, " unlock+wait on uobj",0,
348: 0,0,0);
349: UVM_UNLOCK_AND_WAIT(pg,
350: &pg->uobject->vmobjlock,
351: FALSE, "anonget1",0);
352: } else {
353: /* anon owns page */
354: uvmfault_unlockall(ufi, amap, NULL, NULL);
355: UVMHIST_LOG(maphist, " unlock+wait on anon",0,
356: 0,0,0);
357: UVM_UNLOCK_AND_WAIT(pg,&anon->an_lock,0,
358: "anonget2",0);
359: }
360: } else {
1.101 yamt 361: #if defined(VMSWAP)
1.63 chs 362:
1.7 mrg 363: /*
364: * no page, we must try and bring it in.
365: */
1.69 chs 366:
1.28 chs 367: pg = uvm_pagealloc(NULL, 0, anon, 0);
1.7 mrg 368: if (pg == NULL) { /* out of RAM. */
369: uvmfault_unlockall(ufi, amap, NULL, anon);
370: uvmexp.fltnoram++;
371: UVMHIST_LOG(maphist, " noram -- UVM_WAIT",0,
372: 0,0,0);
1.93 yamt 373: if (!uvm_reclaimable()) {
374: return ENOMEM;
375: }
1.7 mrg 376: uvm_wait("flt_noram1");
377: } else {
378: /* we set the PG_BUSY bit */
1.63 chs 379: we_own = TRUE;
1.7 mrg 380: uvmfault_unlockall(ufi, amap, NULL, anon);
381:
382: /*
383: * we are passing a PG_BUSY+PG_FAKE+PG_CLEAN
384: * page into the uvm_swap_get function with
1.18 chuck 385: * all data structures unlocked. note that
386: * it is ok to read an_swslot here because
387: * we hold PG_BUSY on the page.
1.7 mrg 388: */
389: uvmexp.pageins++;
1.58 chs 390: error = uvm_swap_get(pg, anon->an_swslot,
1.7 mrg 391: PGO_SYNCIO);
392:
393: /*
394: * we clean up after the i/o below in the
395: * "we_own" case
396: */
397: }
1.101 yamt 398: #else /* defined(VMSWAP) */
399: panic("%s: no page", __func__);
400: #endif /* defined(VMSWAP) */
1.7 mrg 401: }
402:
403: /*
404: * now relock and try again
405: */
406:
407: locked = uvmfault_relock(ufi);
1.47 chs 408: if (locked && amap != NULL) {
1.19 chuck 409: amap_lock(amap);
1.7 mrg 410: }
411: if (locked || we_own)
412: simple_lock(&anon->an_lock);
413:
414: /*
415: * if we own the page (i.e. we set PG_BUSY), then we need
416: * to clean up after the I/O. there are three cases to
417: * consider:
418: * [1] page released during I/O: free anon and ReFault.
1.63 chs 419: * [2] I/O not OK. free the page and cause the fault
1.7 mrg 420: * to fail.
421: * [3] I/O OK! activate the page and sync with the
422: * non-we_own case (i.e. drop anon lock if not locked).
423: */
1.63 chs 424:
1.7 mrg 425: if (we_own) {
1.101 yamt 426: #if defined(VMSWAP)
1.7 mrg 427: if (pg->flags & PG_WANTED) {
1.63 chs 428: wakeup(pg);
1.7 mrg 429: }
1.58 chs 430: if (error) {
1.1 mrg 431:
1.47 chs 432: /*
433: * remove the swap slot from the anon
434: * and mark the anon as having no real slot.
435: * don't free the swap slot, thus preventing
436: * it from being used again.
437: */
1.69 chs 438:
1.84 pk 439: if (anon->an_swslot > 0)
440: uvm_swap_markbad(anon->an_swslot, 1);
1.47 chs 441: anon->an_swslot = SWSLOT_BAD;
442:
1.88 yamt 443: if ((pg->flags & PG_RELEASED) != 0)
444: goto released;
445:
1.47 chs 446: /*
1.7 mrg 447: * note: page was never !PG_BUSY, so it
448: * can't be mapped and thus no need to
449: * pmap_page_protect it...
450: */
1.69 chs 451:
1.7 mrg 452: uvm_lock_pageq();
453: uvm_pagefree(pg);
454: uvm_unlock_pageq();
455:
456: if (locked)
457: uvmfault_unlockall(ufi, amap, NULL,
458: anon);
459: else
460: simple_unlock(&anon->an_lock);
461: UVMHIST_LOG(maphist, "<- ERROR", 0,0,0,0);
1.58 chs 462: return error;
1.7 mrg 463: }
1.63 chs 464:
1.88 yamt 465: if ((pg->flags & PG_RELEASED) != 0) {
466: released:
467: KASSERT(anon->an_ref == 0);
468:
469: /*
470: * released while we unlocked amap.
471: */
472:
473: if (locked)
474: uvmfault_unlockall(ufi, amap, NULL,
475: NULL);
476:
477: uvm_anon_release(anon);
478:
479: if (error) {
480: UVMHIST_LOG(maphist,
481: "<- ERROR/RELEASED", 0,0,0,0);
482: return error;
483: }
484:
485: UVMHIST_LOG(maphist, "<- RELEASED", 0,0,0,0);
486: return ERESTART;
487: }
488:
1.7 mrg 489: /*
1.69 chs 490: * we've successfully read the page, activate it.
1.7 mrg 491: */
1.69 chs 492:
1.7 mrg 493: uvm_lock_pageq();
494: uvm_pageactivate(pg);
495: uvm_unlock_pageq();
1.69 chs 496: pg->flags &= ~(PG_WANTED|PG_BUSY|PG_FAKE);
497: UVM_PAGE_OWN(pg, NULL);
1.7 mrg 498: if (!locked)
499: simple_unlock(&anon->an_lock);
1.101 yamt 500: #else /* defined(VMSWAP) */
501: panic("%s: we_own", __func__);
502: #endif /* defined(VMSWAP) */
1.7 mrg 503: }
504:
505: /*
506: * we were not able to relock. restart fault.
507: */
508:
509: if (!locked) {
510: UVMHIST_LOG(maphist, "<- REFAULT", 0,0,0,0);
1.57 chs 511: return (ERESTART);
1.7 mrg 512: }
513:
514: /*
515: * verify no one has touched the amap and moved the anon on us.
516: */
1.1 mrg 517:
1.47 chs 518: if (ufi != NULL &&
1.63 chs 519: amap_lookup(&ufi->entry->aref,
1.47 chs 520: ufi->orig_rvaddr - ufi->entry->start) != anon) {
1.63 chs 521:
1.7 mrg 522: uvmfault_unlockall(ufi, amap, NULL, anon);
523: UVMHIST_LOG(maphist, "<- REFAULT", 0,0,0,0);
1.57 chs 524: return (ERESTART);
1.7 mrg 525: }
1.63 chs 526:
1.7 mrg 527: /*
1.63 chs 528: * try it again!
1.7 mrg 529: */
1.1 mrg 530:
1.7 mrg 531: uvmexp.fltanretry++;
532: continue;
1.69 chs 533: }
1.7 mrg 534: /*NOTREACHED*/
1.1 mrg 535: }
536:
537: /*
1.106 yamt 538: * uvmfault_promote: promote data to a new anon. used for 1B and 2B.
539: *
540: * 1. allocate an anon and a page.
541: * 2. fill its contents.
542: * 3. put it into amap.
543: *
544: * => if we fail (result != 0) we unlock everything.
545: * => on success, return a new locked anon via 'nanon'.
546: * (*nanon)->an_page will be a resident, locked, dirty page.
547: */
548:
549: static int
550: uvmfault_promote(struct uvm_faultinfo *ufi,
551: struct vm_anon *oanon,
552: struct vm_page *uobjpage,
553: struct vm_anon **nanon, /* OUT: allocated anon */
554: struct vm_anon **spare)
555: {
556: struct vm_amap *amap = ufi->entry->aref.ar_amap;
557: struct uvm_object *uobj;
558: struct vm_anon *anon;
559: struct vm_page *pg;
560: struct vm_page *opg;
561: int error;
562: UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
563:
564: if (oanon) {
565: /* anon COW */
566: opg = oanon->an_page;
567: KASSERT(opg != NULL);
568: KASSERT(opg->uobject == NULL || opg->loan_count > 0);
569: } else if (uobjpage != PGO_DONTCARE) {
570: /* object-backed COW */
571: opg = uobjpage;
572: } else {
573: /* ZFOD */
574: opg = NULL;
575: }
576: if (opg != NULL) {
577: uobj = opg->uobject;
578: } else {
579: uobj = NULL;
580: }
581:
582: KASSERT(amap != NULL);
583: KASSERT(uobjpage != NULL);
584: KASSERT(uobjpage == PGO_DONTCARE || (uobjpage->flags & PG_BUSY) != 0);
585: LOCK_ASSERT(simple_lock_held(&amap->am_l));
586: LOCK_ASSERT(oanon == NULL || simple_lock_held(&oanon->an_lock));
587: LOCK_ASSERT(uobj == NULL || simple_lock_held(&uobj->vmobjlock));
588: LOCK_ASSERT(*spare == NULL || !simple_lock_held(&(*spare)->an_lock));
589:
590: if (*spare != NULL) {
591: anon = *spare;
592: *spare = NULL;
593: simple_lock(&anon->an_lock);
594: } else if (ufi->map != kernel_map) {
595: anon = uvm_analloc();
596: } else {
597: UVMHIST_LOG(maphist, "kernel_map, unlock and retry", 0,0,0,0);
598:
599: /*
600: * we can't allocate anons with kernel_map locked.
601: */
602:
603: uvm_page_unbusy(&uobjpage, 1);
604: uvmfault_unlockall(ufi, amap, uobj, oanon);
605:
606: *spare = uvm_analloc();
607: if (*spare == NULL) {
608: goto nomem;
609: }
610: simple_unlock(&(*spare)->an_lock);
611: error = ERESTART;
612: goto done;
613: }
614: if (anon) {
615:
616: /*
617: * The new anon is locked.
618: *
619: * if opg == NULL, we want a zero'd, dirty page,
620: * so have uvm_pagealloc() do that for us.
621: */
622:
623: pg = uvm_pagealloc(NULL, 0, anon,
624: (opg == NULL) ? UVM_PGA_ZERO : 0);
625: } else {
626: pg = NULL;
627: }
628:
629: /*
630: * out of memory resources?
631: */
632:
633: if (pg == NULL) {
634: /* save anon for the next try. */
635: if (anon != NULL) {
636: simple_unlock(&anon->an_lock);
637: *spare = anon;
638: }
639:
640: /* unlock and fail ... */
641: uvm_page_unbusy(&uobjpage, 1);
642: uvmfault_unlockall(ufi, amap, uobj, oanon);
643: nomem:
644: if (!uvm_reclaimable()) {
645: UVMHIST_LOG(maphist, "out of VM", 0,0,0,0);
646: uvmexp.fltnoanon++;
647: error = ENOMEM;
648: goto done;
649: }
650:
651: UVMHIST_LOG(maphist, "out of RAM, waiting for more", 0,0,0,0);
652: uvmexp.fltnoram++;
653: uvm_wait("flt_noram5");
654: error = ERESTART;
655: goto done;
656: }
657:
658: /* copy page [pg now dirty] */
659: if (opg) {
660: uvm_pagecopy(opg, pg);
661: }
662:
663: amap_add(&ufi->entry->aref, ufi->orig_rvaddr - ufi->entry->start, anon,
664: oanon != NULL);
665:
666: *nanon = anon;
667: error = 0;
668: done:
669: return error;
670: }
671:
672:
673: /*
1.1 mrg 674: * F A U L T - m a i n e n t r y p o i n t
675: */
676:
677: /*
678: * uvm_fault: page fault handler
679: *
680: * => called from MD code to resolve a page fault
1.63 chs 681: * => VM data structures usually should be unlocked. however, it is
1.1 mrg 682: * possible to call here with the main map locked if the caller
683: * gets a write lock, sets it recusive, and then calls us (c.f.
684: * uvm_map_pageable). this should be avoided because it keeps
685: * the map locked off during I/O.
1.66 thorpej 686: * => MUST NEVER BE CALLED IN INTERRUPT CONTEXT
1.1 mrg 687: */
688:
1.24 mycroft 689: #define MASK(entry) (UVM_ET_ISCOPYONWRITE(entry) ? \
690: ~VM_PROT_WRITE : VM_PROT_ALL)
691:
1.110 drochner 692: /* fault_flag values passed from uvm_fault_wire to uvm_fault_internal */
693: #define UVM_FAULT_WIRE 1
694: #define UVM_FAULT_WIREMAX 2
695:
1.7 mrg 696: int
1.110 drochner 697: uvm_fault_internal(struct vm_map *orig_map, vaddr_t vaddr,
698: vm_prot_t access_type, int fault_flag)
1.1 mrg 699: {
1.7 mrg 700: struct uvm_faultinfo ufi;
1.72 chs 701: vm_prot_t enter_prot, check_prot;
1.73 chs 702: boolean_t wired, narrow, promote, locked, shadowed, wire_fault, cow_now;
1.58 chs 703: int npages, nback, nforw, centeridx, error, lcv, gotpages;
1.90 yamt 704: vaddr_t startva, currva;
1.79 yamt 705: voff_t uoff;
1.7 mrg 706: struct vm_amap *amap;
707: struct uvm_object *uobj;
708: struct vm_anon *anons_store[UVM_MAXRANGE], **anons, *anon, *oanon;
1.106 yamt 709: struct vm_anon *anon_spare;
1.7 mrg 710: struct vm_page *pages[UVM_MAXRANGE], *pg, *uobjpage;
711: UVMHIST_FUNC("uvm_fault"); UVMHIST_CALLED(maphist);
1.1 mrg 712:
1.110 drochner 713: UVMHIST_LOG(maphist, "(map=0x%x, vaddr=0x%x, at=%d, ff=%d)",
714: orig_map, vaddr, access_type, fault_flag);
1.1 mrg 715:
1.106 yamt 716: anon = anon_spare = NULL;
1.52 chs 717: pg = NULL;
1.1 mrg 718:
1.7 mrg 719: uvmexp.faults++; /* XXX: locking? */
720:
721: /*
722: * init the IN parameters in the ufi
723: */
1.1 mrg 724:
1.7 mrg 725: ufi.orig_map = orig_map;
726: ufi.orig_rvaddr = trunc_page(vaddr);
727: ufi.orig_size = PAGE_SIZE; /* can't get any smaller than this */
1.110 drochner 728: wire_fault = (fault_flag > 0);
1.72 chs 729: if (wire_fault)
1.7 mrg 730: narrow = TRUE; /* don't look for neighborhood
731: * pages on wire */
732: else
733: narrow = FALSE; /* normal fault */
734:
735: /*
736: * "goto ReFault" means restart the page fault from ground zero.
737: */
1.1 mrg 738: ReFault:
739:
1.7 mrg 740: /*
741: * lookup and lock the maps
742: */
743:
744: if (uvmfault_lookup(&ufi, FALSE) == FALSE) {
745: UVMHIST_LOG(maphist, "<- no mapping @ 0x%x", vaddr, 0,0,0);
1.106 yamt 746: error = EFAULT;
747: goto done;
1.7 mrg 748: }
749: /* locked: maps(read) */
750:
1.61 thorpej 751: #ifdef DIAGNOSTIC
752: if ((ufi.map->flags & VM_MAP_PAGEABLE) == 0) {
753: printf("Page fault on non-pageable map:\n");
754: printf("ufi.map = %p\n", ufi.map);
755: printf("ufi.orig_map = %p\n", ufi.orig_map);
756: printf("ufi.orig_rvaddr = 0x%lx\n", (u_long) ufi.orig_rvaddr);
757: panic("uvm_fault: (ufi.map->flags & VM_MAP_PAGEABLE) == 0");
758: }
759: #endif
1.58 chs 760:
1.7 mrg 761: /*
762: * check protection
763: */
764:
1.110 drochner 765: check_prot = fault_flag == UVM_FAULT_WIREMAX ?
1.72 chs 766: ufi.entry->max_protection : ufi.entry->protection;
767: if ((check_prot & access_type) != access_type) {
1.7 mrg 768: UVMHIST_LOG(maphist,
769: "<- protection failure (prot=0x%x, access=0x%x)",
770: ufi.entry->protection, access_type, 0, 0);
771: uvmfault_unlockmaps(&ufi, FALSE);
1.106 yamt 772: error = EACCES;
773: goto done;
1.7 mrg 774: }
775:
776: /*
777: * "enter_prot" is the protection we want to enter the page in at.
778: * for certain pages (e.g. copy-on-write pages) this protection can
779: * be more strict than ufi.entry->protection. "wired" means either
780: * the entry is wired or we are fault-wiring the pg.
781: */
782:
783: enter_prot = ufi.entry->protection;
1.72 chs 784: wired = VM_MAPENT_ISWIRED(ufi.entry) || wire_fault;
1.73 chs 785: if (wired) {
1.7 mrg 786: access_type = enter_prot; /* full access for wired */
1.73 chs 787: cow_now = (check_prot & VM_PROT_WRITE) != 0;
788: } else {
789: cow_now = (access_type & VM_PROT_WRITE) != 0;
790: }
1.7 mrg 791:
792: /*
793: * handle "needs_copy" case. if we need to copy the amap we will
794: * have to drop our readlock and relock it with a write lock. (we
795: * need a write lock to change anything in a map entry [e.g.
796: * needs_copy]).
797: */
798:
799: if (UVM_ET_ISNEEDSCOPY(ufi.entry)) {
1.73 chs 800: if (cow_now || (ufi.entry->object.uvm_obj == NULL)) {
1.112.2.2! yamt 801: KASSERT(fault_flag != UVM_FAULT_WIREMAX);
1.7 mrg 802: /* need to clear */
803: UVMHIST_LOG(maphist,
804: " need to clear needs_copy and refault",0,0,0,0);
805: uvmfault_unlockmaps(&ufi, FALSE);
806: uvmfault_amapcopy(&ufi);
807: uvmexp.fltamcopy++;
808: goto ReFault;
809:
810: } else {
811:
812: /*
813: * ensure that we pmap_enter page R/O since
814: * needs_copy is still true
815: */
1.72 chs 816:
1.63 chs 817: enter_prot &= ~VM_PROT_WRITE;
1.7 mrg 818: }
819: }
820:
821: /*
822: * identify the players
823: */
824:
1.46 thorpej 825: amap = ufi.entry->aref.ar_amap; /* top layer */
1.7 mrg 826: uobj = ufi.entry->object.uvm_obj; /* bottom layer */
827:
828: /*
829: * check for a case 0 fault. if nothing backing the entry then
830: * error now.
831: */
832:
833: if (amap == NULL && uobj == NULL) {
834: uvmfault_unlockmaps(&ufi, FALSE);
835: UVMHIST_LOG(maphist,"<- no backing store, no overlay",0,0,0,0);
1.106 yamt 836: error = EFAULT;
837: goto done;
1.7 mrg 838: }
1.1 mrg 839:
1.7 mrg 840: /*
841: * establish range of interest based on advice from mapper
842: * and then clip to fit map entry. note that we only want
1.63 chs 843: * to do this the first time through the fault. if we
1.7 mrg 844: * ReFault we will disable this by setting "narrow" to true.
845: */
1.1 mrg 846:
1.7 mrg 847: if (narrow == FALSE) {
848:
849: /* wide fault (!narrow) */
1.52 chs 850: KASSERT(uvmadvice[ufi.entry->advice].advice ==
851: ufi.entry->advice);
1.69 chs 852: nback = MIN(uvmadvice[ufi.entry->advice].nback,
1.15 chs 853: (ufi.orig_rvaddr - ufi.entry->start) >> PAGE_SHIFT);
854: startva = ufi.orig_rvaddr - (nback << PAGE_SHIFT);
1.69 chs 855: nforw = MIN(uvmadvice[ufi.entry->advice].nforw,
1.15 chs 856: ((ufi.entry->end - ufi.orig_rvaddr) >>
857: PAGE_SHIFT) - 1);
1.7 mrg 858: /*
859: * note: "-1" because we don't want to count the
860: * faulting page as forw
861: */
862: npages = nback + nforw + 1;
863: centeridx = nback;
864:
1.43 cgd 865: narrow = TRUE; /* ensure only once per-fault */
1.7 mrg 866:
867: } else {
1.63 chs 868:
1.7 mrg 869: /* narrow fault! */
870: nback = nforw = 0;
1.13 chuck 871: startva = ufi.orig_rvaddr;
1.7 mrg 872: npages = 1;
873: centeridx = 0;
1.1 mrg 874:
1.7 mrg 875: }
1.1 mrg 876:
1.7 mrg 877: /* locked: maps(read) */
1.13 chuck 878: UVMHIST_LOG(maphist, " narrow=%d, back=%d, forw=%d, startva=0x%x",
1.16 chs 879: narrow, nback, nforw, startva);
1.7 mrg 880: UVMHIST_LOG(maphist, " entry=0x%x, amap=0x%x, obj=0x%x", ufi.entry,
1.16 chs 881: amap, uobj, 0);
1.1 mrg 882:
1.7 mrg 883: /*
884: * if we've got an amap, lock it and extract current anons.
885: */
886:
887: if (amap) {
1.19 chuck 888: amap_lock(amap);
1.7 mrg 889: anons = anons_store;
890: amap_lookups(&ufi.entry->aref, startva - ufi.entry->start,
891: anons, npages);
892: } else {
893: anons = NULL; /* to be safe */
894: }
895:
896: /* locked: maps(read), amap(if there) */
1.111 yamt 897: LOCK_ASSERT(amap == NULL || simple_lock_held(&amap->am_l));
1.7 mrg 898:
899: /*
900: * for MADV_SEQUENTIAL mappings we want to deactivate the back pages
901: * now and then forget about them (for the rest of the fault).
902: */
903:
1.70 chs 904: if (ufi.entry->advice == MADV_SEQUENTIAL && nback != 0) {
1.7 mrg 905:
906: UVMHIST_LOG(maphist, " MADV_SEQUENTIAL: flushing backpages",
907: 0,0,0,0);
908: /* flush back-page anons? */
1.63 chs 909: if (amap)
1.7 mrg 910: uvmfault_anonflush(anons, nback);
911:
912: /* flush object? */
913: if (uobj) {
1.90 yamt 914: uoff = (startva - ufi.entry->start) + ufi.entry->offset;
1.7 mrg 915: simple_lock(&uobj->vmobjlock);
1.90 yamt 916: (void) (uobj->pgops->pgo_put)(uobj, uoff, uoff +
1.15 chs 917: (nback << PAGE_SHIFT), PGO_DEACTIVATE);
1.7 mrg 918: }
919:
920: /* now forget about the backpages */
921: if (amap)
922: anons += nback;
1.52 chs 923: startva += (nback << PAGE_SHIFT);
1.7 mrg 924: npages -= nback;
925: nback = centeridx = 0;
926: }
927:
928: /* locked: maps(read), amap(if there) */
1.111 yamt 929: LOCK_ASSERT(amap == NULL || simple_lock_held(&amap->am_l));
1.1 mrg 930:
1.7 mrg 931: /*
932: * map in the backpages and frontpages we found in the amap in hopes
933: * of preventing future faults. we also init the pages[] array as
934: * we go.
935: */
936:
1.13 chuck 937: currva = startva;
1.7 mrg 938: shadowed = FALSE;
939: for (lcv = 0 ; lcv < npages ; lcv++, currva += PAGE_SIZE) {
940:
941: /*
942: * dont play with VAs that are already mapped
1.13 chuck 943: * except for center)
1.7 mrg 944: */
1.52 chs 945: if (lcv != centeridx &&
1.89 yamt 946: pmap_extract(ufi.orig_map->pmap, currva, NULL)) {
1.52 chs 947: pages[lcv] = PGO_DONTCARE;
948: continue;
1.7 mrg 949: }
950:
951: /*
952: * unmapped or center page. check if any anon at this level.
953: */
954: if (amap == NULL || anons[lcv] == NULL) {
955: pages[lcv] = NULL;
956: continue;
957: }
958:
959: /*
960: * check for present page and map if possible. re-activate it.
961: */
962:
963: pages[lcv] = PGO_DONTCARE;
964: if (lcv == centeridx) { /* save center for later! */
965: shadowed = TRUE;
966: continue;
967: }
968: anon = anons[lcv];
969: simple_lock(&anon->an_lock);
970: /* ignore loaned pages */
1.94 yamt 971: if (anon->an_page && anon->an_page->loan_count == 0 &&
972: (anon->an_page->flags & PG_BUSY) == 0) {
1.7 mrg 973: uvm_lock_pageq();
1.112 yamt 974: uvm_pageenqueue(anon->an_page);
1.7 mrg 975: uvm_unlock_pageq();
976: UVMHIST_LOG(maphist,
977: " MAPPING: n anon: pm=0x%x, va=0x%x, pg=0x%x",
1.94 yamt 978: ufi.orig_map->pmap, currva, anon->an_page, 0);
1.7 mrg 979: uvmexp.fltnamap++;
1.52 chs 980:
1.46 thorpej 981: /*
982: * Since this isn't the page that's actually faulting,
983: * ignore pmap_enter() failures; it's not critical
984: * that we enter these right now.
985: */
1.52 chs 986:
1.46 thorpej 987: (void) pmap_enter(ufi.orig_map->pmap, currva,
1.94 yamt 988: VM_PAGE_TO_PHYS(anon->an_page),
1.25 mycroft 989: (anon->an_ref > 1) ? (enter_prot & ~VM_PROT_WRITE) :
1.46 thorpej 990: enter_prot,
991: PMAP_CANFAIL |
992: (VM_MAPENT_ISWIRED(ufi.entry) ? PMAP_WIRED : 0));
1.7 mrg 993: }
994: simple_unlock(&anon->an_lock);
1.68 chris 995: pmap_update(ufi.orig_map->pmap);
1.7 mrg 996: }
997:
998: /* locked: maps(read), amap(if there) */
1.111 yamt 999: LOCK_ASSERT(amap == NULL || simple_lock_held(&amap->am_l));
1.7 mrg 1000: /* (shadowed == TRUE) if there is an anon at the faulting address */
1.63 chs 1001: UVMHIST_LOG(maphist, " shadowed=%d, will_get=%d", shadowed,
1.17 mrg 1002: (uobj && shadowed == FALSE),0,0);
1.1 mrg 1003:
1.7 mrg 1004: /*
1005: * note that if we are really short of RAM we could sleep in the above
1006: * call to pmap_enter with everything locked. bad?
1.46 thorpej 1007: *
1008: * XXX Actually, that is bad; pmap_enter() should just fail in that
1009: * XXX case. --thorpej
1.7 mrg 1010: */
1.63 chs 1011:
1.7 mrg 1012: /*
1013: * if the desired page is not shadowed by the amap and we have a
1014: * backing object, then we check to see if the backing object would
1015: * prefer to handle the fault itself (rather than letting us do it
1016: * with the usual pgo_get hook). the backing object signals this by
1017: * providing a pgo_fault routine.
1018: */
1.1 mrg 1019:
1.7 mrg 1020: if (uobj && shadowed == FALSE && uobj->pgops->pgo_fault != NULL) {
1021: simple_lock(&uobj->vmobjlock);
1.1 mrg 1022:
1.7 mrg 1023: /* locked: maps(read), amap (if there), uobj */
1.58 chs 1024: error = uobj->pgops->pgo_fault(&ufi, startva, pages, npages,
1.109 drochner 1025: centeridx, access_type, PGO_LOCKED|PGO_SYNCIO);
1.52 chs 1026:
1.7 mrg 1027: /* locked: nothing, pgo_fault has unlocked everything */
1028:
1.59 chs 1029: if (error == ERESTART)
1.7 mrg 1030: goto ReFault; /* try again! */
1.61 thorpej 1031: /*
1032: * object fault routine responsible for pmap_update().
1033: */
1.106 yamt 1034: goto done;
1.7 mrg 1035: }
1036:
1037: /*
1038: * now, if the desired page is not shadowed by the amap and we have
1039: * a backing object that does not have a special fault routine, then
1040: * we ask (with pgo_get) the object for resident pages that we care
1041: * about and attempt to map them in. we do not let pgo_get block
1042: * (PGO_LOCKED).
1043: */
1044:
1045: if (uobj && shadowed == FALSE) {
1046: simple_lock(&uobj->vmobjlock);
1.1 mrg 1047:
1.7 mrg 1048: /* locked (!shadowed): maps(read), amap (if there), uobj */
1049: /*
1050: * the following call to pgo_get does _not_ change locking state
1051: */
1052:
1053: uvmexp.fltlget++;
1054: gotpages = npages;
1.52 chs 1055: (void) uobj->pgops->pgo_get(uobj, ufi.entry->offset +
1.1 mrg 1056: (startva - ufi.entry->start),
1057: pages, &gotpages, centeridx,
1.24 mycroft 1058: access_type & MASK(ufi.entry),
1.1 mrg 1059: ufi.entry->advice, PGO_LOCKED);
1060:
1.7 mrg 1061: /*
1062: * check for pages to map, if we got any
1063: */
1064:
1065: uobjpage = NULL;
1066:
1067: if (gotpages) {
1.13 chuck 1068: currva = startva;
1.69 chs 1069: for (lcv = 0; lcv < npages;
1070: lcv++, currva += PAGE_SIZE) {
1.86 yamt 1071: struct vm_page *curpg;
1072: boolean_t readonly;
1073:
1074: curpg = pages[lcv];
1075: if (curpg == NULL || curpg == PGO_DONTCARE) {
1.7 mrg 1076: continue;
1.69 chs 1077: }
1.107 yamt 1078: KASSERT(curpg->uobject == uobj);
1.1 mrg 1079:
1.52 chs 1080: /*
1081: * if center page is resident and not
1082: * PG_BUSY|PG_RELEASED then pgo_get
1083: * made it PG_BUSY for us and gave
1084: * us a handle to it. remember this
1085: * page as "uobjpage." (for later use).
1086: */
1.63 chs 1087:
1.52 chs 1088: if (lcv == centeridx) {
1.86 yamt 1089: uobjpage = curpg;
1.52 chs 1090: UVMHIST_LOG(maphist, " got uobjpage "
1.63 chs 1091: "(0x%x) with locked get",
1.7 mrg 1092: uobjpage, 0,0,0);
1.52 chs 1093: continue;
1.7 mrg 1094: }
1.63 chs 1095:
1096: /*
1.69 chs 1097: * calling pgo_get with PGO_LOCKED returns us
1098: * pages which are neither busy nor released,
1099: * so we don't need to check for this.
1100: * we can just directly enter the pages.
1.7 mrg 1101: */
1102:
1103: uvm_lock_pageq();
1.112 yamt 1104: uvm_pageenqueue(curpg);
1.7 mrg 1105: uvm_unlock_pageq();
1106: UVMHIST_LOG(maphist,
1107: " MAPPING: n obj: pm=0x%x, va=0x%x, pg=0x%x",
1.86 yamt 1108: ufi.orig_map->pmap, currva, curpg, 0);
1.7 mrg 1109: uvmexp.fltnomap++;
1.52 chs 1110:
1.46 thorpej 1111: /*
1112: * Since this page isn't the page that's
1.85 dbj 1113: * actually faulting, ignore pmap_enter()
1.46 thorpej 1114: * failures; it's not critical that we
1115: * enter these right now.
1116: */
1.86 yamt 1117: KASSERT((curpg->flags & PG_PAGEOUT) == 0);
1118: KASSERT((curpg->flags & PG_RELEASED) == 0);
1.97 yamt 1119: KASSERT(!UVM_OBJ_IS_CLEAN(curpg->uobject) ||
1.96 yamt 1120: (curpg->flags & PG_CLEAN) != 0);
1.86 yamt 1121: readonly = (curpg->flags & PG_RDONLY)
1.96 yamt 1122: || (curpg->loan_count > 0)
1.98 yamt 1123: || UVM_OBJ_NEEDS_WRITEFAULT(curpg->uobject);
1.52 chs 1124:
1.46 thorpej 1125: (void) pmap_enter(ufi.orig_map->pmap, currva,
1.86 yamt 1126: VM_PAGE_TO_PHYS(curpg),
1127: readonly ?
1.76 chs 1128: enter_prot & ~VM_PROT_WRITE :
1129: enter_prot & MASK(ufi.entry),
1.46 thorpej 1130: PMAP_CANFAIL |
1131: (wired ? PMAP_WIRED : 0));
1.7 mrg 1132:
1.63 chs 1133: /*
1.7 mrg 1134: * NOTE: page can't be PG_WANTED or PG_RELEASED
1135: * because we've held the lock the whole time
1136: * we've had the handle.
1137: */
1.111 yamt 1138: KASSERT((curpg->flags & PG_WANTED) == 0);
1139: KASSERT((curpg->flags & PG_RELEASED) == 0);
1.52 chs 1140:
1.86 yamt 1141: curpg->flags &= ~(PG_BUSY);
1142: UVM_PAGE_OWN(curpg, NULL);
1.69 chs 1143: }
1.68 chris 1144: pmap_update(ufi.orig_map->pmap);
1.69 chs 1145: }
1.7 mrg 1146: } else {
1147: uobjpage = NULL;
1148: }
1149:
1150: /* locked (shadowed): maps(read), amap */
1.63 chs 1151: /* locked (!shadowed): maps(read), amap(if there),
1.7 mrg 1152: uobj(if !null), uobjpage(if !null) */
1.111 yamt 1153: if (shadowed) {
1154: LOCK_ASSERT(simple_lock_held(&amap->am_l));
1155: } else {
1156: LOCK_ASSERT(amap == NULL || simple_lock_held(&amap->am_l));
1157: LOCK_ASSERT(uobj == NULL || simple_lock_held(&uobj->vmobjlock));
1158: KASSERT(uobjpage == NULL || (uobjpage->flags & PG_BUSY) != 0);
1159: }
1.7 mrg 1160:
1161: /*
1162: * note that at this point we are done with any front or back pages.
1163: * we are now going to focus on the center page (i.e. the one we've
1164: * faulted on). if we have faulted on the top (anon) layer
1165: * [i.e. case 1], then the anon we want is anons[centeridx] (we have
1166: * not touched it yet). if we have faulted on the bottom (uobj)
1167: * layer [i.e. case 2] and the page was both present and available,
1168: * then we've got a pointer to it as "uobjpage" and we've already
1.8 chuck 1169: * made it BUSY.
1.7 mrg 1170: */
1171:
1172: /*
1173: * there are four possible cases we must address: 1A, 1B, 2A, and 2B
1174: */
1175:
1176: /*
1177: * redirect case 2: if we are not shadowed, go to case 2.
1178: */
1179:
1.63 chs 1180: if (shadowed == FALSE)
1.7 mrg 1181: goto Case2;
1182:
1183: /* locked: maps(read), amap */
1184:
1185: /*
1186: * handle case 1: fault on an anon in our amap
1187: */
1188:
1189: anon = anons[centeridx];
1190: UVMHIST_LOG(maphist, " case 1 fault: anon=0x%x", anon, 0,0,0);
1191: simple_lock(&anon->an_lock);
1192:
1193: /* locked: maps(read), amap, anon */
1.111 yamt 1194: LOCK_ASSERT(simple_lock_held(&amap->am_l));
1195: LOCK_ASSERT(simple_lock_held(&anon->an_lock));
1.7 mrg 1196:
1197: /*
1198: * no matter if we have case 1A or case 1B we are going to need to
1199: * have the anon's memory resident. ensure that now.
1200: */
1201:
1202: /*
1.47 chs 1203: * let uvmfault_anonget do the dirty work.
1.51 thorpej 1204: * if it fails (!OK) it will unlock everything for us.
1.47 chs 1205: * if it succeeds, locks are still valid and locked.
1.7 mrg 1206: * also, if it is OK, then the anon's page is on the queues.
1207: * if the page is on loan from a uvm_object, then anonget will
1208: * lock that object for us if it does not fail.
1209: */
1210:
1.58 chs 1211: error = uvmfault_anonget(&ufi, amap, anon);
1212: switch (error) {
1.57 chs 1213: case 0:
1.63 chs 1214: break;
1.7 mrg 1215:
1.57 chs 1216: case ERESTART:
1.7 mrg 1217: goto ReFault;
1218:
1.57 chs 1219: case EAGAIN:
1.52 chs 1220: tsleep(&lbolt, PVM, "fltagain1", 0);
1221: goto ReFault;
1.51 thorpej 1222:
1223: default:
1.106 yamt 1224: goto done;
1.1 mrg 1225: }
1.7 mrg 1226:
1227: /*
1228: * uobj is non null if the page is on loan from an object (i.e. uobj)
1229: */
1230:
1.94 yamt 1231: uobj = anon->an_page->uobject; /* locked by anonget if !NULL */
1.7 mrg 1232:
1233: /* locked: maps(read), amap, anon, uobj(if one) */
1.111 yamt 1234: LOCK_ASSERT(simple_lock_held(&amap->am_l));
1235: LOCK_ASSERT(simple_lock_held(&anon->an_lock));
1236: LOCK_ASSERT(uobj == NULL || simple_lock_held(&uobj->vmobjlock));
1.7 mrg 1237:
1238: /*
1.63 chs 1239: * special handling for loaned pages
1.7 mrg 1240: */
1.52 chs 1241:
1.94 yamt 1242: if (anon->an_page->loan_count) {
1.7 mrg 1243:
1.73 chs 1244: if (!cow_now) {
1.63 chs 1245:
1.7 mrg 1246: /*
1247: * for read faults on loaned pages we just cap the
1248: * protection at read-only.
1249: */
1250:
1251: enter_prot = enter_prot & ~VM_PROT_WRITE;
1252:
1253: } else {
1254: /*
1255: * note that we can't allow writes into a loaned page!
1256: *
1257: * if we have a write fault on a loaned page in an
1258: * anon then we need to look at the anon's ref count.
1259: * if it is greater than one then we are going to do
1260: * a normal copy-on-write fault into a new anon (this
1261: * is not a problem). however, if the reference count
1262: * is one (a case where we would normally allow a
1263: * write directly to the page) then we need to kill
1264: * the loan before we continue.
1265: */
1266:
1267: /* >1 case is already ok */
1268: if (anon->an_ref == 1) {
1269:
1270: /* get new un-owned replacement page */
1.28 chs 1271: pg = uvm_pagealloc(NULL, 0, NULL, 0);
1.7 mrg 1272: if (pg == NULL) {
1273: uvmfault_unlockall(&ufi, amap, uobj,
1274: anon);
1275: uvm_wait("flt_noram2");
1276: goto ReFault;
1277: }
1278:
1279: /*
1280: * copy data, kill loan, and drop uobj lock
1281: * (if any)
1282: */
1283: /* copy old -> new */
1.94 yamt 1284: uvm_pagecopy(anon->an_page, pg);
1.7 mrg 1285:
1286: /* force reload */
1.112.2.2! yamt 1287: pmap_page_protect(anon->an_page, VM_PROT_NONE);
1.7 mrg 1288: uvm_lock_pageq(); /* KILL loan */
1.78 thorpej 1289:
1.94 yamt 1290: anon->an_page->uanon = NULL;
1.7 mrg 1291: /* in case we owned */
1.94 yamt 1292: anon->an_page->pqflags &= ~PQ_ANON;
1.78 thorpej 1293:
1294: if (uobj) {
1295: /* if we were receiver of loan */
1.94 yamt 1296: anon->an_page->loan_count--;
1.78 thorpej 1297: } else {
1298: /*
1299: * we were the lender (A->K); need
1300: * to remove the page from pageq's.
1301: */
1.94 yamt 1302: uvm_pagedequeue(anon->an_page);
1.78 thorpej 1303: }
1304:
1.7 mrg 1305: if (uobj) {
1306: simple_unlock(&uobj->vmobjlock);
1307: uobj = NULL;
1308: }
1309:
1310: /* install new page in anon */
1.94 yamt 1311: anon->an_page = pg;
1.7 mrg 1312: pg->uanon = anon;
1313: pg->pqflags |= PQ_ANON;
1.112 yamt 1314:
1315: uvm_pageactivate(pg);
1316: uvm_unlock_pageq();
1317:
1.7 mrg 1318: pg->flags &= ~(PG_BUSY|PG_FAKE);
1319: UVM_PAGE_OWN(pg, NULL);
1320:
1321: /* done! */
1322: } /* ref == 1 */
1323: } /* write fault */
1324: } /* loan count */
1325:
1326: /*
1327: * if we are case 1B then we will need to allocate a new blank
1328: * anon to transfer the data into. note that we have a lock
1329: * on anon, so no one can busy or release the page until we are done.
1330: * also note that the ref count can't drop to zero here because
1331: * it is > 1 and we are only dropping one ref.
1332: *
1.63 chs 1333: * in the (hopefully very rare) case that we are out of RAM we
1334: * will unlock, wait for more RAM, and refault.
1.7 mrg 1335: *
1336: * if we are out of anon VM we kill the process (XXX: could wait?).
1337: */
1338:
1.73 chs 1339: if (cow_now && anon->an_ref > 1) {
1.7 mrg 1340:
1341: UVMHIST_LOG(maphist, " case 1B: COW fault",0,0,0,0);
1342: uvmexp.flt_acow++;
1343: oanon = anon; /* oanon = old, locked anon */
1.22 chs 1344:
1.106 yamt 1345: error = uvmfault_promote(&ufi, oanon, PGO_DONTCARE,
1346: &anon, &anon_spare);
1347: switch (error) {
1348: case 0:
1349: break;
1350: case ERESTART:
1.7 mrg 1351: goto ReFault;
1.106 yamt 1352: default:
1353: goto done;
1.7 mrg 1354: }
1355:
1.106 yamt 1356: pg = anon->an_page;
1.81 pk 1357: uvm_lock_pageq();
1.69 chs 1358: uvm_pageactivate(pg);
1.106 yamt 1359: uvm_unlock_pageq();
1.105 yamt 1360: pg->flags &= ~(PG_BUSY|PG_FAKE);
1.7 mrg 1361: UVM_PAGE_OWN(pg, NULL);
1362:
1363: /* deref: can not drop to zero here by defn! */
1364: oanon->an_ref--;
1.53 thorpej 1365:
1.7 mrg 1366: /*
1.53 thorpej 1367: * note: oanon is still locked, as is the new anon. we
1368: * need to check for this later when we unlock oanon; if
1369: * oanon != anon, we'll have to unlock anon, too.
1.7 mrg 1370: */
1371:
1372: } else {
1.52 chs 1373:
1.7 mrg 1374: uvmexp.flt_anon++;
1375: oanon = anon; /* old, locked anon is same as anon */
1.94 yamt 1376: pg = anon->an_page;
1.7 mrg 1377: if (anon->an_ref > 1) /* disallow writes to ref > 1 anons */
1378: enter_prot = enter_prot & ~VM_PROT_WRITE;
1379:
1380: }
1381:
1.53 thorpej 1382: /* locked: maps(read), amap, oanon, anon (if different from oanon) */
1.111 yamt 1383: LOCK_ASSERT(simple_lock_held(&amap->am_l));
1384: LOCK_ASSERT(simple_lock_held(&anon->an_lock));
1385: LOCK_ASSERT(simple_lock_held(&oanon->an_lock));
1.7 mrg 1386:
1387: /*
1.69 chs 1388: * now map the page in.
1.7 mrg 1389: */
1390:
1391: UVMHIST_LOG(maphist, " MAPPING: anon: pm=0x%x, va=0x%x, pg=0x%x",
1392: ufi.orig_map->pmap, ufi.orig_rvaddr, pg, 0);
1.46 thorpej 1393: if (pmap_enter(ufi.orig_map->pmap, ufi.orig_rvaddr, VM_PAGE_TO_PHYS(pg),
1394: enter_prot, access_type | PMAP_CANFAIL | (wired ? PMAP_WIRED : 0))
1.58 chs 1395: != 0) {
1.69 chs 1396:
1.46 thorpej 1397: /*
1398: * No need to undo what we did; we can simply think of
1399: * this as the pmap throwing away the mapping information.
1400: *
1401: * We do, however, have to go through the ReFault path,
1402: * as the map may change while we're asleep.
1403: */
1.69 chs 1404:
1.53 thorpej 1405: if (anon != oanon)
1406: simple_unlock(&anon->an_lock);
1.46 thorpej 1407: uvmfault_unlockall(&ufi, amap, uobj, oanon);
1.92 yamt 1408: if (!uvm_reclaimable()) {
1.46 thorpej 1409: UVMHIST_LOG(maphist,
1410: "<- failed. out of VM",0,0,0,0);
1411: /* XXX instrumentation */
1.106 yamt 1412: error = ENOMEM;
1413: goto done;
1.46 thorpej 1414: }
1415: /* XXX instrumentation */
1416: uvm_wait("flt_pmfail1");
1417: goto ReFault;
1418: }
1.7 mrg 1419:
1420: /*
1.46 thorpej 1421: * ... update the page queues.
1.7 mrg 1422: */
1423:
1424: uvm_lock_pageq();
1.72 chs 1425: if (wire_fault) {
1.8 chuck 1426: uvm_pagewire(pg);
1.29 chs 1427:
1428: /*
1429: * since the now-wired page cannot be paged out,
1430: * release its swap resources for others to use.
1431: * since an anon with no swap cannot be PG_CLEAN,
1432: * clear its clean flag now.
1433: */
1434:
1435: pg->flags &= ~(PG_CLEAN);
1.22 chs 1436: uvm_anon_dropswap(anon);
1.7 mrg 1437: } else {
1438: uvm_pageactivate(pg);
1439: }
1440: uvm_unlock_pageq();
1441:
1442: /*
1443: * done case 1! finish up by unlocking everything and returning success
1444: */
1.1 mrg 1445:
1.53 thorpej 1446: if (anon != oanon)
1447: simple_unlock(&anon->an_lock);
1.7 mrg 1448: uvmfault_unlockall(&ufi, amap, uobj, oanon);
1.68 chris 1449: pmap_update(ufi.orig_map->pmap);
1.106 yamt 1450: error = 0;
1451: goto done;
1.1 mrg 1452:
1453: Case2:
1.7 mrg 1454: /*
1455: * handle case 2: faulting on backing object or zero fill
1456: */
1457:
1458: /*
1459: * locked:
1460: * maps(read), amap(if there), uobj(if !null), uobjpage(if !null)
1461: */
1.111 yamt 1462: LOCK_ASSERT(amap == NULL || simple_lock_held(&amap->am_l));
1463: LOCK_ASSERT(uobj == NULL || simple_lock_held(&uobj->vmobjlock));
1464: LOCK_ASSERT(uobjpage == NULL || (uobjpage->flags & PG_BUSY) != 0);
1.7 mrg 1465:
1466: /*
1467: * note that uobjpage can not be PGO_DONTCARE at this point. we now
1468: * set uobjpage to PGO_DONTCARE if we are doing a zero fill. if we
1469: * have a backing object, check and see if we are going to promote
1470: * the data up to an anon during the fault.
1471: */
1472:
1473: if (uobj == NULL) {
1.63 chs 1474: uobjpage = PGO_DONTCARE;
1.7 mrg 1475: promote = TRUE; /* always need anon here */
1476: } else {
1.52 chs 1477: KASSERT(uobjpage != PGO_DONTCARE);
1.73 chs 1478: promote = cow_now && UVM_ET_ISCOPYONWRITE(ufi.entry);
1.7 mrg 1479: }
1480: UVMHIST_LOG(maphist, " case 2 fault: promote=%d, zfill=%d",
1.46 thorpej 1481: promote, (uobj == NULL), 0,0);
1.1 mrg 1482:
1.7 mrg 1483: /*
1.9 chuck 1484: * if uobjpage is not null then we do not need to do I/O to get the
1485: * uobjpage.
1486: *
1.63 chs 1487: * if uobjpage is null, then we need to unlock and ask the pager to
1.7 mrg 1488: * get the data for us. once we have the data, we need to reverify
1489: * the state the world. we are currently not holding any resources.
1490: */
1.1 mrg 1491:
1.9 chuck 1492: if (uobjpage) {
1493: /* update rusage counters */
1.80 thorpej 1494: curproc->p_stats->p_ru.ru_minflt++;
1.9 chuck 1495: } else {
1496: /* update rusage counters */
1.80 thorpej 1497: curproc->p_stats->p_ru.ru_majflt++;
1.63 chs 1498:
1.7 mrg 1499: /* locked: maps(read), amap(if there), uobj */
1500: uvmfault_unlockall(&ufi, amap, NULL, NULL);
1501: /* locked: uobj */
1502:
1503: uvmexp.fltget++;
1504: gotpages = 1;
1.52 chs 1505: uoff = (ufi.orig_rvaddr - ufi.entry->start) + ufi.entry->offset;
1.58 chs 1506: error = uobj->pgops->pgo_get(uobj, uoff, &uobjpage, &gotpages,
1.52 chs 1507: 0, access_type & MASK(ufi.entry), ufi.entry->advice,
1508: PGO_SYNCIO);
1.58 chs 1509: /* locked: uobjpage(if no error) */
1.111 yamt 1510: LOCK_ASSERT(error != 0 || (uobjpage->flags & PG_BUSY) != 0);
1.52 chs 1511:
1.7 mrg 1512: /*
1513: * recover from I/O
1514: */
1.1 mrg 1515:
1.58 chs 1516: if (error) {
1517: if (error == EAGAIN) {
1.46 thorpej 1518: UVMHIST_LOG(maphist,
1519: " pgo_get says TRY AGAIN!",0,0,0,0);
1.57 chs 1520: tsleep(&lbolt, PVM, "fltagain2", 0);
1.46 thorpej 1521: goto ReFault;
1.7 mrg 1522: }
1.1 mrg 1523:
1.7 mrg 1524: UVMHIST_LOG(maphist, "<- pgo_get failed (code %d)",
1.58 chs 1525: error, 0,0,0);
1.106 yamt 1526: goto done;
1.7 mrg 1527: }
1528:
1529: /* locked: uobjpage */
1530:
1.69 chs 1531: uvm_lock_pageq();
1532: uvm_pageactivate(uobjpage);
1533: uvm_unlock_pageq();
1534:
1.7 mrg 1535: /*
1536: * re-verify the state of the world by first trying to relock
1537: * the maps. always relock the object.
1538: */
1539:
1540: locked = uvmfault_relock(&ufi);
1541: if (locked && amap)
1.19 chuck 1542: amap_lock(amap);
1.107 yamt 1543: uobj = uobjpage->uobject;
1.7 mrg 1544: simple_lock(&uobj->vmobjlock);
1.63 chs 1545:
1.7 mrg 1546: /* locked(locked): maps(read), amap(if !null), uobj, uobjpage */
1547: /* locked(!locked): uobj, uobjpage */
1548:
1549: /*
1550: * verify that the page has not be released and re-verify
1551: * that amap slot is still free. if there is a problem,
1552: * we unlock and clean up.
1553: */
1554:
1555: if ((uobjpage->flags & PG_RELEASED) != 0 ||
1.63 chs 1556: (locked && amap &&
1.7 mrg 1557: amap_lookup(&ufi.entry->aref,
1.13 chuck 1558: ufi.orig_rvaddr - ufi.entry->start))) {
1.63 chs 1559: if (locked)
1.7 mrg 1560: uvmfault_unlockall(&ufi, amap, NULL, NULL);
1561: locked = FALSE;
1562: }
1563:
1564: /*
1565: * didn't get the lock? release the page and retry.
1566: */
1567:
1568: if (locked == FALSE) {
1569: UVMHIST_LOG(maphist,
1.63 chs 1570: " wasn't able to relock after fault: retry",
1.7 mrg 1571: 0,0,0,0);
1572: if (uobjpage->flags & PG_WANTED)
1.44 thorpej 1573: wakeup(uobjpage);
1.7 mrg 1574: if (uobjpage->flags & PG_RELEASED) {
1575: uvmexp.fltpgrele++;
1.69 chs 1576: uvm_pagefree(uobjpage);
1.7 mrg 1577: goto ReFault;
1578: }
1579: uobjpage->flags &= ~(PG_BUSY|PG_WANTED);
1580: UVM_PAGE_OWN(uobjpage, NULL);
1581: simple_unlock(&uobj->vmobjlock);
1582: goto ReFault;
1583: }
1584:
1585: /*
1.69 chs 1586: * we have the data in uobjpage which is busy and
1587: * not released. we are holding object lock (so the page
1.7 mrg 1588: * can't be released on us).
1589: */
1590:
1591: /* locked: maps(read), amap(if !null), uobj, uobjpage */
1592: }
1.1 mrg 1593:
1594: /*
1.7 mrg 1595: * locked:
1596: * maps(read), amap(if !null), uobj(if !null), uobjpage(if uobj)
1.1 mrg 1597: */
1.111 yamt 1598: LOCK_ASSERT(amap == NULL || simple_lock_held(&amap->am_l));
1599: LOCK_ASSERT(uobj == NULL || simple_lock_held(&uobj->vmobjlock));
1600: LOCK_ASSERT(uobj == NULL || (uobjpage->flags & PG_BUSY) != 0);
1.1 mrg 1601:
1.7 mrg 1602: /*
1603: * notes:
1604: * - at this point uobjpage can not be NULL
1605: * - at this point uobjpage can not be PG_RELEASED (since we checked
1606: * for it above)
1607: * - at this point uobjpage could be PG_WANTED (handle later)
1608: */
1.63 chs 1609:
1.107 yamt 1610: KASSERT(uobj == NULL || uobj == uobjpage->uobject);
1.97 yamt 1611: KASSERT(uobj == NULL || !UVM_OBJ_IS_CLEAN(uobjpage->uobject) ||
1.96 yamt 1612: (uobjpage->flags & PG_CLEAN) != 0);
1.7 mrg 1613: if (promote == FALSE) {
1.1 mrg 1614:
1.7 mrg 1615: /*
1616: * we are not promoting. if the mapping is COW ensure that we
1617: * don't give more access than we should (e.g. when doing a read
1618: * fault on a COPYONWRITE mapping we want to map the COW page in
1619: * R/O even though the entry protection could be R/W).
1620: *
1621: * set "pg" to the page we want to map in (uobjpage, usually)
1622: */
1623:
1.53 thorpej 1624: /* no anon in this case. */
1625: anon = NULL;
1626:
1.7 mrg 1627: uvmexp.flt_obj++;
1.96 yamt 1628: if (UVM_ET_ISCOPYONWRITE(ufi.entry) ||
1.98 yamt 1629: UVM_OBJ_NEEDS_WRITEFAULT(uobjpage->uobject))
1.24 mycroft 1630: enter_prot &= ~VM_PROT_WRITE;
1.7 mrg 1631: pg = uobjpage; /* map in the actual object */
1632:
1.111 yamt 1633: KASSERT(uobjpage != PGO_DONTCARE);
1.7 mrg 1634:
1635: /*
1636: * we are faulting directly on the page. be careful
1637: * about writing to loaned pages...
1638: */
1.69 chs 1639:
1.7 mrg 1640: if (uobjpage->loan_count) {
1.73 chs 1641: if (!cow_now) {
1.7 mrg 1642: /* read fault: cap the protection at readonly */
1643: /* cap! */
1644: enter_prot = enter_prot & ~VM_PROT_WRITE;
1645: } else {
1646: /* write fault: must break the loan here */
1647:
1.82 yamt 1648: pg = uvm_loanbreak(uobjpage);
1.7 mrg 1649: if (pg == NULL) {
1.69 chs 1650:
1.7 mrg 1651: /*
1652: * drop ownership of page, it can't
1653: * be released
1.46 thorpej 1654: */
1.69 chs 1655:
1.7 mrg 1656: if (uobjpage->flags & PG_WANTED)
1.44 thorpej 1657: wakeup(uobjpage);
1.7 mrg 1658: uobjpage->flags &= ~(PG_BUSY|PG_WANTED);
1659: UVM_PAGE_OWN(uobjpage, NULL);
1660:
1661: uvmfault_unlockall(&ufi, amap, uobj,
1662: NULL);
1663: UVMHIST_LOG(maphist,
1.20 mrg 1664: " out of RAM breaking loan, waiting",
1665: 0,0,0,0);
1.7 mrg 1666: uvmexp.fltnoram++;
1667: uvm_wait("flt_noram4");
1668: goto ReFault;
1669: }
1670: uobjpage = pg;
1.69 chs 1671: }
1672: }
1.7 mrg 1673: } else {
1.63 chs 1674:
1.7 mrg 1675: /*
1676: * if we are going to promote the data to an anon we
1677: * allocate a blank anon here and plug it into our amap.
1678: */
1.1 mrg 1679: #if DIAGNOSTIC
1.7 mrg 1680: if (amap == NULL)
1681: panic("uvm_fault: want to promote data, but no anon");
1.1 mrg 1682: #endif
1.106 yamt 1683: error = uvmfault_promote(&ufi, NULL, uobjpage,
1684: &anon, &anon_spare);
1685: switch (error) {
1686: case 0:
1687: break;
1688: case ERESTART:
1689: goto ReFault;
1690: default:
1691: goto done;
1.105 yamt 1692: }
1693:
1.106 yamt 1694: pg = anon->an_page;
1.1 mrg 1695:
1.7 mrg 1696: /*
1697: * fill in the data
1698: */
1699:
1700: if (uobjpage != PGO_DONTCARE) {
1701: uvmexp.flt_prcopy++;
1702:
1703: /*
1704: * promote to shared amap? make sure all sharing
1705: * procs see it
1706: */
1.69 chs 1707:
1.19 chuck 1708: if ((amap_flags(amap) & AMAP_SHARED) != 0) {
1.45 chs 1709: pmap_page_protect(uobjpage, VM_PROT_NONE);
1.62 thorpej 1710: /*
1711: * XXX: PAGE MIGHT BE WIRED!
1712: */
1.7 mrg 1713: }
1.63 chs 1714:
1.7 mrg 1715: /*
1716: * dispose of uobjpage. it can't be PG_RELEASED
1.52 chs 1717: * since we still hold the object lock.
1718: * drop handle to uobj as well.
1.7 mrg 1719: */
1720:
1721: if (uobjpage->flags & PG_WANTED)
1722: /* still have the obj lock */
1.44 thorpej 1723: wakeup(uobjpage);
1.7 mrg 1724: uobjpage->flags &= ~(PG_BUSY|PG_WANTED);
1725: UVM_PAGE_OWN(uobjpage, NULL);
1726: simple_unlock(&uobj->vmobjlock);
1727: uobj = NULL;
1.52 chs 1728:
1.7 mrg 1729: UVMHIST_LOG(maphist,
1730: " promote uobjpage 0x%x to anon/page 0x%x/0x%x",
1731: uobjpage, anon, pg, 0);
1732:
1733: } else {
1734: uvmexp.flt_przero++;
1.69 chs 1735:
1.48 thorpej 1736: /*
1.106 yamt 1737: * Page is zero'd and marked dirty by
1738: * uvmfault_promote().
1.48 thorpej 1739: */
1.69 chs 1740:
1.7 mrg 1741: UVMHIST_LOG(maphist," zero fill anon/page 0x%x/0%x",
1742: anon, pg, 0, 0);
1743: }
1744: }
1745:
1746: /*
1747: * locked:
1.53 thorpej 1748: * maps(read), amap(if !null), uobj(if !null), uobjpage(if uobj),
1749: * anon(if !null), pg(if anon)
1.7 mrg 1750: *
1751: * note: pg is either the uobjpage or the new page in the new anon
1752: */
1.111 yamt 1753: LOCK_ASSERT(amap == NULL || simple_lock_held(&amap->am_l));
1754: LOCK_ASSERT(uobj == NULL || simple_lock_held(&uobj->vmobjlock));
1755: LOCK_ASSERT(uobj == NULL || (uobjpage->flags & PG_BUSY) != 0);
1756: LOCK_ASSERT(anon == NULL || simple_lock_held(&anon->an_lock));
1757: LOCK_ASSERT((pg->flags & PG_BUSY) != 0);
1.7 mrg 1758:
1759: /*
1760: * all resources are present. we can now map it in and free our
1761: * resources.
1762: */
1763:
1764: UVMHIST_LOG(maphist,
1765: " MAPPING: case2: pm=0x%x, va=0x%x, pg=0x%x, promote=%d",
1766: ufi.orig_map->pmap, ufi.orig_rvaddr, pg, promote);
1.75 chs 1767: KASSERT((access_type & VM_PROT_WRITE) == 0 ||
1768: (pg->flags & PG_RDONLY) == 0);
1.46 thorpej 1769: if (pmap_enter(ufi.orig_map->pmap, ufi.orig_rvaddr, VM_PAGE_TO_PHYS(pg),
1.76 chs 1770: pg->flags & PG_RDONLY ? enter_prot & ~VM_PROT_WRITE : enter_prot,
1.58 chs 1771: access_type | PMAP_CANFAIL | (wired ? PMAP_WIRED : 0)) != 0) {
1.52 chs 1772:
1.46 thorpej 1773: /*
1774: * No need to undo what we did; we can simply think of
1775: * this as the pmap throwing away the mapping information.
1776: *
1777: * We do, however, have to go through the ReFault path,
1778: * as the map may change while we're asleep.
1779: */
1.52 chs 1780:
1.46 thorpej 1781: if (pg->flags & PG_WANTED)
1.69 chs 1782: wakeup(pg);
1.46 thorpej 1783:
1.63 chs 1784: /*
1.46 thorpej 1785: * note that pg can't be PG_RELEASED since we did not drop
1786: * the object lock since the last time we checked.
1787: */
1.111 yamt 1788: KASSERT((pg->flags & PG_RELEASED) == 0);
1.63 chs 1789:
1.46 thorpej 1790: pg->flags &= ~(PG_BUSY|PG_FAKE|PG_WANTED);
1791: UVM_PAGE_OWN(pg, NULL);
1.53 thorpej 1792: uvmfault_unlockall(&ufi, amap, uobj, anon);
1.92 yamt 1793: if (!uvm_reclaimable()) {
1.46 thorpej 1794: UVMHIST_LOG(maphist,
1795: "<- failed. out of VM",0,0,0,0);
1796: /* XXX instrumentation */
1.106 yamt 1797: error = ENOMEM;
1798: goto done;
1.46 thorpej 1799: }
1800: /* XXX instrumentation */
1801: uvm_wait("flt_pmfail2");
1802: goto ReFault;
1803: }
1.1 mrg 1804:
1805: uvm_lock_pageq();
1.72 chs 1806: if (wire_fault) {
1.8 chuck 1807: uvm_pagewire(pg);
1.22 chs 1808: if (pg->pqflags & PQ_AOBJ) {
1.29 chs 1809:
1810: /*
1811: * since the now-wired page cannot be paged out,
1812: * release its swap resources for others to use.
1813: * since an aobj page with no swap cannot be PG_CLEAN,
1814: * clear its clean flag now.
1815: */
1816:
1.112.2.1 yamt 1817: KASSERT(uobj != NULL);
1.29 chs 1818: pg->flags &= ~(PG_CLEAN);
1.22 chs 1819: uao_dropswap(uobj, pg->offset >> PAGE_SHIFT);
1820: }
1.7 mrg 1821: } else {
1822: uvm_pageactivate(pg);
1823: }
1.1 mrg 1824: uvm_unlock_pageq();
1.7 mrg 1825: if (pg->flags & PG_WANTED)
1.69 chs 1826: wakeup(pg);
1.7 mrg 1827:
1.63 chs 1828: /*
1829: * note that pg can't be PG_RELEASED since we did not drop the object
1.7 mrg 1830: * lock since the last time we checked.
1831: */
1.111 yamt 1832: KASSERT((pg->flags & PG_RELEASED) == 0);
1.63 chs 1833:
1.7 mrg 1834: pg->flags &= ~(PG_BUSY|PG_FAKE|PG_WANTED);
1835: UVM_PAGE_OWN(pg, NULL);
1.53 thorpej 1836: uvmfault_unlockall(&ufi, amap, uobj, anon);
1.68 chris 1837: pmap_update(ufi.orig_map->pmap);
1.7 mrg 1838: UVMHIST_LOG(maphist, "<- done (SUCCESS!)",0,0,0,0);
1.106 yamt 1839: error = 0;
1840: done:
1841: if (anon_spare != NULL) {
1842: anon_spare->an_ref--;
1843: uvm_anfree(anon_spare);
1844: }
1845: return error;
1.1 mrg 1846: }
1847:
1.110 drochner 1848:
1.1 mrg 1849: /*
1850: * uvm_fault_wire: wire down a range of virtual addresses in a map.
1851: *
1.36 thorpej 1852: * => map may be read-locked by caller, but MUST NOT be write-locked.
1853: * => if map is read-locked, any operations which may cause map to
1854: * be write-locked in uvm_fault() must be taken care of by
1855: * the caller. See uvm_map_pageable().
1.1 mrg 1856: */
1857:
1.7 mrg 1858: int
1.95 thorpej 1859: uvm_fault_wire(struct vm_map *map, vaddr_t start, vaddr_t end,
1.110 drochner 1860: vm_prot_t access_type, int wiremax)
1.7 mrg 1861: {
1.12 eeh 1862: vaddr_t va;
1.58 chs 1863: int error;
1.7 mrg 1864:
1865: /*
1.47 chs 1866: * now fault it in a page at a time. if the fault fails then we have
1.63 chs 1867: * to undo what we have done. note that in uvm_fault VM_PROT_NONE
1.47 chs 1868: * is replaced with the max protection if fault_type is VM_FAULT_WIRE.
1.7 mrg 1869: */
1.1 mrg 1870:
1.65 chs 1871: /*
1872: * XXX work around overflowing a vaddr_t. this prevents us from
1873: * wiring the last page in the address space, though.
1874: */
1875: if (start > end) {
1876: return EFAULT;
1877: }
1878:
1.7 mrg 1879: for (va = start ; va < end ; va += PAGE_SIZE) {
1.110 drochner 1880: error = uvm_fault_internal(map, va, access_type,
1881: wiremax ? UVM_FAULT_WIREMAX : UVM_FAULT_WIRE);
1.58 chs 1882: if (error) {
1.7 mrg 1883: if (va != start) {
1.31 thorpej 1884: uvm_fault_unwire(map, start, va);
1.7 mrg 1885: }
1.58 chs 1886: return error;
1.7 mrg 1887: }
1888: }
1.58 chs 1889: return 0;
1.1 mrg 1890: }
1891:
1892: /*
1893: * uvm_fault_unwire(): unwire range of virtual space.
1894: */
1895:
1.7 mrg 1896: void
1.95 thorpej 1897: uvm_fault_unwire(struct vm_map *map, vaddr_t start, vaddr_t end)
1.36 thorpej 1898: {
1899: vm_map_lock_read(map);
1900: uvm_fault_unwire_locked(map, start, end);
1901: vm_map_unlock_read(map);
1902: }
1903:
1904: /*
1905: * uvm_fault_unwire_locked(): the guts of uvm_fault_unwire().
1906: *
1907: * => map must be at least read-locked.
1908: */
1909:
1910: void
1.95 thorpej 1911: uvm_fault_unwire_locked(struct vm_map *map, vaddr_t start, vaddr_t end)
1.7 mrg 1912: {
1.64 chs 1913: struct vm_map_entry *entry;
1.31 thorpej 1914: pmap_t pmap = vm_map_pmap(map);
1.42 thorpej 1915: vaddr_t va;
1.12 eeh 1916: paddr_t pa;
1.42 thorpej 1917: struct vm_page *pg;
1.31 thorpej 1918:
1.52 chs 1919: KASSERT((map->flags & VM_MAP_INTRSAFE) == 0);
1.7 mrg 1920:
1921: /*
1922: * we assume that the area we are unwiring has actually been wired
1923: * in the first place. this means that we should be able to extract
1924: * the PAs from the pmap. we also lock out the page daemon so that
1925: * we can call uvm_pageunwire.
1926: */
1.37 thorpej 1927:
1.7 mrg 1928: uvm_lock_pageq();
1929:
1.37 thorpej 1930: /*
1931: * find the beginning map entry for the region.
1932: */
1.74 chs 1933:
1.56 chs 1934: KASSERT(start >= vm_map_min(map) && end <= vm_map_max(map));
1.37 thorpej 1935: if (uvm_map_lookup_entry(map, start, &entry) == FALSE)
1936: panic("uvm_fault_unwire_locked: address not in map");
1937:
1.69 chs 1938: for (va = start; va < end; va += PAGE_SIZE) {
1.42 thorpej 1939: if (pmap_extract(pmap, va, &pa) == FALSE)
1.74 chs 1940: continue;
1.42 thorpej 1941:
1942: /*
1.74 chs 1943: * find the map entry for the current address.
1.42 thorpej 1944: */
1.56 chs 1945:
1946: KASSERT(va >= entry->start);
1.74 chs 1947: while (va >= entry->end) {
1.56 chs 1948: KASSERT(entry->next != &map->header &&
1949: entry->next->start <= entry->end);
1.42 thorpej 1950: entry = entry->next;
1951: }
1.37 thorpej 1952:
1.42 thorpej 1953: /*
1954: * if the entry is no longer wired, tell the pmap.
1955: */
1.74 chs 1956:
1.42 thorpej 1957: if (VM_MAPENT_ISWIRED(entry) == 0)
1958: pmap_unwire(pmap, va);
1959:
1960: pg = PHYS_TO_VM_PAGE(pa);
1961: if (pg)
1962: uvm_pageunwire(pg);
1.7 mrg 1963: }
1.1 mrg 1964:
1.7 mrg 1965: uvm_unlock_pageq();
1.1 mrg 1966: }
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