xref: /titanic_41/usr/src/uts/common/vm/seg_spt.c (revision c73e9863820a560b7fbb4fb258aa450a88315a39)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <sys/param.h>
29 #include <sys/user.h>
30 #include <sys/mman.h>
31 #include <sys/kmem.h>
32 #include <sys/sysmacros.h>
33 #include <sys/cmn_err.h>
34 #include <sys/systm.h>
35 #include <sys/tuneable.h>
36 #include <vm/hat.h>
37 #include <vm/seg.h>
38 #include <vm/as.h>
39 #include <vm/anon.h>
40 #include <vm/page.h>
41 #include <sys/buf.h>
42 #include <sys/swap.h>
43 #include <sys/atomic.h>
44 #include <vm/seg_spt.h>
45 #include <sys/debug.h>
46 #include <sys/vtrace.h>
47 #include <sys/shm.h>
48 #include <sys/shm_impl.h>
49 #include <sys/lgrp.h>
50 #include <sys/vmsystm.h>
51 #include <sys/policy.h>
52 #include <sys/project.h>
53 #include <sys/tnf_probe.h>
54 #include <sys/zone.h>
55 
56 #define	SEGSPTADDR	(caddr_t)0x0
57 
58 /*
59  * # pages used for spt
60  */
61 size_t	spt_used;
62 
63 /*
64  * segspt_minfree is the memory left for system after ISM
65  * locked its pages; it is set up to 5% of availrmem in
66  * sptcreate when ISM is created.  ISM should not use more
67  * than ~90% of availrmem; if it does, then the performance
68  * of the system may decrease. Machines with large memories may
69  * be able to use up more memory for ISM so we set the default
70  * segspt_minfree to 5% (which gives ISM max 95% of availrmem.
71  * If somebody wants even more memory for ISM (risking hanging
72  * the system) they can patch the segspt_minfree to smaller number.
73  */
74 pgcnt_t segspt_minfree = 0;
75 
76 static int segspt_create(struct seg *seg, caddr_t argsp);
77 static int segspt_unmap(struct seg *seg, caddr_t raddr, size_t ssize);
78 static void segspt_free(struct seg *seg);
79 static void segspt_free_pages(struct seg *seg, caddr_t addr, size_t len);
80 static lgrp_mem_policy_info_t *segspt_getpolicy(struct seg *seg, caddr_t addr);
81 
82 static void
83 segspt_badop()
84 {
85 	panic("segspt_badop called");
86 	/*NOTREACHED*/
87 }
88 
89 #define	SEGSPT_BADOP(t)	(t(*)())segspt_badop
90 
91 struct seg_ops segspt_ops = {
92 	SEGSPT_BADOP(int),		/* dup */
93 	segspt_unmap,
94 	segspt_free,
95 	SEGSPT_BADOP(int),		/* fault */
96 	SEGSPT_BADOP(faultcode_t),	/* faulta */
97 	SEGSPT_BADOP(int),		/* setprot */
98 	SEGSPT_BADOP(int),		/* checkprot */
99 	SEGSPT_BADOP(int),		/* kluster */
100 	SEGSPT_BADOP(size_t),		/* swapout */
101 	SEGSPT_BADOP(int),		/* sync */
102 	SEGSPT_BADOP(size_t),		/* incore */
103 	SEGSPT_BADOP(int),		/* lockop */
104 	SEGSPT_BADOP(int),		/* getprot */
105 	SEGSPT_BADOP(u_offset_t), 	/* getoffset */
106 	SEGSPT_BADOP(int),		/* gettype */
107 	SEGSPT_BADOP(int),		/* getvp */
108 	SEGSPT_BADOP(int),		/* advise */
109 	SEGSPT_BADOP(void),		/* dump */
110 	SEGSPT_BADOP(int),		/* pagelock */
111 	SEGSPT_BADOP(int),		/* setpgsz */
112 	SEGSPT_BADOP(int),		/* getmemid */
113 	segspt_getpolicy,		/* getpolicy */
114 	SEGSPT_BADOP(int),		/* capable */
115 };
116 
117 static int segspt_shmdup(struct seg *seg, struct seg *newseg);
118 static int segspt_shmunmap(struct seg *seg, caddr_t raddr, size_t ssize);
119 static void segspt_shmfree(struct seg *seg);
120 static faultcode_t segspt_shmfault(struct hat *hat, struct seg *seg,
121 		caddr_t addr, size_t len, enum fault_type type, enum seg_rw rw);
122 static faultcode_t segspt_shmfaulta(struct seg *seg, caddr_t addr);
123 static int segspt_shmsetprot(register struct seg *seg, register caddr_t addr,
124 			register size_t len, register uint_t prot);
125 static int segspt_shmcheckprot(struct seg *seg, caddr_t addr, size_t size,
126 			uint_t prot);
127 static int	segspt_shmkluster(struct seg *seg, caddr_t addr, ssize_t delta);
128 static size_t	segspt_shmswapout(struct seg *seg);
129 static size_t segspt_shmincore(struct seg *seg, caddr_t addr, size_t len,
130 			register char *vec);
131 static int segspt_shmsync(struct seg *seg, register caddr_t addr, size_t len,
132 			int attr, uint_t flags);
133 static int segspt_shmlockop(struct seg *seg, caddr_t addr, size_t len,
134 			int attr, int op, ulong_t *lockmap, size_t pos);
135 static int segspt_shmgetprot(struct seg *seg, caddr_t addr, size_t len,
136 			uint_t *protv);
137 static u_offset_t segspt_shmgetoffset(struct seg *seg, caddr_t addr);
138 static int segspt_shmgettype(struct seg *seg, caddr_t addr);
139 static int segspt_shmgetvp(struct seg *seg, caddr_t addr, struct vnode **vpp);
140 static int segspt_shmadvise(struct seg *seg, caddr_t addr, size_t len,
141 			uint_t behav);
142 static void segspt_shmdump(struct seg *seg);
143 static int segspt_shmpagelock(struct seg *, caddr_t, size_t,
144 			struct page ***, enum lock_type, enum seg_rw);
145 static int segspt_shmsetpgsz(struct seg *, caddr_t, size_t, uint_t);
146 static int segspt_shmgetmemid(struct seg *, caddr_t, memid_t *);
147 static lgrp_mem_policy_info_t *segspt_shmgetpolicy(struct seg *, caddr_t);
148 static int segspt_shmcapable(struct seg *, segcapability_t);
149 
150 struct seg_ops segspt_shmops = {
151 	segspt_shmdup,
152 	segspt_shmunmap,
153 	segspt_shmfree,
154 	segspt_shmfault,
155 	segspt_shmfaulta,
156 	segspt_shmsetprot,
157 	segspt_shmcheckprot,
158 	segspt_shmkluster,
159 	segspt_shmswapout,
160 	segspt_shmsync,
161 	segspt_shmincore,
162 	segspt_shmlockop,
163 	segspt_shmgetprot,
164 	segspt_shmgetoffset,
165 	segspt_shmgettype,
166 	segspt_shmgetvp,
167 	segspt_shmadvise,	/* advise */
168 	segspt_shmdump,
169 	segspt_shmpagelock,
170 	segspt_shmsetpgsz,
171 	segspt_shmgetmemid,
172 	segspt_shmgetpolicy,
173 	segspt_shmcapable,
174 };
175 
176 static void segspt_purge(struct seg *seg);
177 static int segspt_reclaim(struct seg *, caddr_t, size_t, struct page **,
178 		enum seg_rw);
179 static int spt_anon_getpages(struct seg *seg, caddr_t addr, size_t len,
180 		page_t **ppa);
181 
182 
183 
184 /*ARGSUSED*/
185 int
186 sptcreate(size_t size, struct seg **sptseg, struct anon_map *amp,
187 	uint_t prot, uint_t flags, uint_t share_szc)
188 {
189 	int 	err;
190 	struct  as	*newas;
191 	struct	segspt_crargs sptcargs;
192 
193 #ifdef DEBUG
194 	TNF_PROBE_1(sptcreate, "spt", /* CSTYLED */,
195 			tnf_ulong, size, size );
196 #endif
197 	if (segspt_minfree == 0)	/* leave min 5% of availrmem for */
198 		segspt_minfree = availrmem/20;	/* for the system */
199 
200 	if (!hat_supported(HAT_SHARED_PT, (void *)0))
201 		return (EINVAL);
202 
203 	/*
204 	 * get a new as for this shared memory segment
205 	 */
206 	newas = as_alloc();
207 	newas->a_proc = NULL;
208 	sptcargs.amp = amp;
209 	sptcargs.prot = prot;
210 	sptcargs.flags = flags;
211 	sptcargs.szc = share_szc;
212 	/*
213 	 * create a shared page table (spt) segment
214 	 */
215 
216 	if (err = as_map(newas, SEGSPTADDR, size, segspt_create, &sptcargs)) {
217 		as_free(newas);
218 		return (err);
219 	}
220 	*sptseg = sptcargs.seg_spt;
221 	return (0);
222 }
223 
224 void
225 sptdestroy(struct as *as, struct anon_map *amp)
226 {
227 
228 #ifdef DEBUG
229 	TNF_PROBE_0(sptdestroy, "spt", /* CSTYLED */);
230 #endif
231 	(void) as_unmap(as, SEGSPTADDR, amp->size);
232 	as_free(as);
233 }
234 
235 /*
236  * called from seg_free().
237  * free (i.e., unlock, unmap, return to free list)
238  *  all the pages in the given seg.
239  */
240 void
241 segspt_free(struct seg	*seg)
242 {
243 	struct spt_data *sptd = (struct spt_data *)seg->s_data;
244 
245 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
246 
247 	if (sptd != NULL) {
248 		if (sptd->spt_realsize)
249 			segspt_free_pages(seg, seg->s_base, sptd->spt_realsize);
250 
251 	if (sptd->spt_ppa_lckcnt)
252 		kmem_free(sptd->spt_ppa_lckcnt,
253 		    sizeof (*sptd->spt_ppa_lckcnt)
254 		    * btopr(sptd->spt_amp->size));
255 		kmem_free(sptd->spt_vp, sizeof (*sptd->spt_vp));
256 		cv_destroy(&sptd->spt_cv);
257 		mutex_destroy(&sptd->spt_lock);
258 		kmem_free(sptd, sizeof (*sptd));
259 	}
260 }
261 
262 /*ARGSUSED*/
263 static int
264 segspt_shmsync(struct seg *seg, caddr_t addr, size_t len, int attr,
265 	uint_t flags)
266 {
267 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
268 
269 	return (0);
270 }
271 
272 /*ARGSUSED*/
273 static size_t
274 segspt_shmincore(struct seg *seg, caddr_t addr, size_t len, char *vec)
275 {
276 	caddr_t	eo_seg;
277 	pgcnt_t	npages;
278 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
279 	struct seg	*sptseg;
280 	struct spt_data *sptd;
281 
282 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
283 #ifdef lint
284 	seg = seg;
285 #endif
286 	sptseg = shmd->shm_sptseg;
287 	sptd = sptseg->s_data;
288 
289 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
290 		eo_seg = addr + len;
291 		while (addr < eo_seg) {
292 			/* page exists, and it's locked. */
293 			*vec++ = SEG_PAGE_INCORE | SEG_PAGE_LOCKED |
294 			    SEG_PAGE_ANON;
295 			addr += PAGESIZE;
296 		}
297 		return (len);
298 	} else {
299 		struct  anon_map *amp = shmd->shm_amp;
300 		struct  anon	*ap;
301 		page_t		*pp;
302 		pgcnt_t 	anon_index;
303 		struct vnode 	*vp;
304 		u_offset_t 	off;
305 		ulong_t		i;
306 		int		ret;
307 		anon_sync_obj_t	cookie;
308 
309 		addr = (caddr_t)((uintptr_t)addr & (uintptr_t)PAGEMASK);
310 		anon_index = seg_page(seg, addr);
311 		npages = btopr(len);
312 		if (anon_index + npages > btopr(shmd->shm_amp->size)) {
313 			return (EINVAL);
314 		}
315 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
316 		for (i = 0; i < npages; i++, anon_index++) {
317 			ret = 0;
318 			anon_array_enter(amp, anon_index, &cookie);
319 			ap = anon_get_ptr(amp->ahp, anon_index);
320 			if (ap != NULL) {
321 				swap_xlate(ap, &vp, &off);
322 				anon_array_exit(&cookie);
323 				pp = page_lookup_nowait(vp, off, SE_SHARED);
324 				if (pp != NULL) {
325 					ret |= SEG_PAGE_INCORE | SEG_PAGE_ANON;
326 					page_unlock(pp);
327 				}
328 			} else {
329 				anon_array_exit(&cookie);
330 			}
331 			if (shmd->shm_vpage[anon_index] & DISM_PG_LOCKED) {
332 				ret |= SEG_PAGE_LOCKED;
333 			}
334 			*vec++ = (char)ret;
335 		}
336 		ANON_LOCK_EXIT(&amp->a_rwlock);
337 		return (len);
338 	}
339 }
340 
341 static int
342 segspt_unmap(struct seg *seg, caddr_t raddr, size_t ssize)
343 {
344 	size_t share_size;
345 
346 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
347 
348 	/*
349 	 * seg.s_size may have been rounded up to the largest page size
350 	 * in shmat().
351 	 * XXX This should be cleanedup. sptdestroy should take a length
352 	 * argument which should be the same as sptcreate. Then
353 	 * this rounding would not be needed (or is done in shm.c)
354 	 * Only the check for full segment will be needed.
355 	 *
356 	 * XXX -- shouldn't raddr == 0 always? These tests don't seem
357 	 * to be useful at all.
358 	 */
359 	share_size = page_get_pagesize(seg->s_szc);
360 	ssize = P2ROUNDUP(ssize, share_size);
361 
362 	if (raddr == seg->s_base && ssize == seg->s_size) {
363 		seg_free(seg);
364 		return (0);
365 	} else
366 		return (EINVAL);
367 }
368 
369 int
370 segspt_create(struct seg *seg, caddr_t argsp)
371 {
372 	int		err;
373 	caddr_t		addr = seg->s_base;
374 	struct spt_data *sptd;
375 	struct 	segspt_crargs *sptcargs = (struct segspt_crargs *)argsp;
376 	struct anon_map *amp = sptcargs->amp;
377 	struct kshmid	*sp = amp->a_sp;
378 	struct	cred	*cred = CRED();
379 	ulong_t		i, j, anon_index = 0;
380 	pgcnt_t		npages = btopr(amp->size);
381 	struct vnode	*vp;
382 	page_t		**ppa;
383 	uint_t		hat_flags;
384 	size_t		pgsz;
385 	pgcnt_t		pgcnt;
386 	caddr_t		a;
387 	pgcnt_t		pidx;
388 	size_t		sz;
389 	proc_t		*procp = curproc;
390 	rctl_qty_t	lockedbytes = 0;
391 	kproject_t	*proj;
392 
393 	/*
394 	 * We are holding the a_lock on the underlying dummy as,
395 	 * so we can make calls to the HAT layer.
396 	 */
397 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
398 	ASSERT(sp != NULL);
399 
400 #ifdef DEBUG
401 	TNF_PROBE_2(segspt_create, "spt", /* CSTYLED */,
402 	    tnf_opaque, addr, addr, tnf_ulong, len, seg->s_size);
403 #endif
404 	if ((sptcargs->flags & SHM_PAGEABLE) == 0) {
405 		if (err = anon_swap_adjust(npages))
406 			return (err);
407 	}
408 	err = ENOMEM;
409 
410 	if ((sptd = kmem_zalloc(sizeof (*sptd), KM_NOSLEEP)) == NULL)
411 		goto out1;
412 
413 	if ((sptcargs->flags & SHM_PAGEABLE) == 0) {
414 		if ((ppa = kmem_zalloc(((sizeof (page_t *)) * npages),
415 		    KM_NOSLEEP)) == NULL)
416 			goto out2;
417 	}
418 
419 	mutex_init(&sptd->spt_lock, NULL, MUTEX_DEFAULT, NULL);
420 
421 	if ((vp = kmem_zalloc(sizeof (*vp), KM_NOSLEEP)) == NULL)
422 		goto out3;
423 
424 	seg->s_ops = &segspt_ops;
425 	sptd->spt_vp = vp;
426 	sptd->spt_amp = amp;
427 	sptd->spt_prot = sptcargs->prot;
428 	sptd->spt_flags = sptcargs->flags;
429 	seg->s_data = (caddr_t)sptd;
430 	sptd->spt_ppa = NULL;
431 	sptd->spt_ppa_lckcnt = NULL;
432 	seg->s_szc = sptcargs->szc;
433 	cv_init(&sptd->spt_cv, NULL, CV_DEFAULT, NULL);
434 	sptd->spt_gen = 0;
435 
436 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
437 	if (seg->s_szc > amp->a_szc) {
438 		amp->a_szc = seg->s_szc;
439 	}
440 	ANON_LOCK_EXIT(&amp->a_rwlock);
441 
442 	/*
443 	 * Set policy to affect initial allocation of pages in
444 	 * anon_map_createpages()
445 	 */
446 	(void) lgrp_shm_policy_set(LGRP_MEM_POLICY_DEFAULT, amp, anon_index,
447 	    NULL, 0, ptob(npages));
448 
449 	if (sptcargs->flags & SHM_PAGEABLE) {
450 		size_t  share_sz;
451 		pgcnt_t new_npgs, more_pgs;
452 		struct anon_hdr *nahp;
453 		zone_t *zone;
454 
455 		share_sz = page_get_pagesize(seg->s_szc);
456 		if (!IS_P2ALIGNED(amp->size, share_sz)) {
457 			/*
458 			 * We are rounding up the size of the anon array
459 			 * on 4 M boundary because we always create 4 M
460 			 * of page(s) when locking, faulting pages and we
461 			 * don't have to check for all corner cases e.g.
462 			 * if there is enough space to allocate 4 M
463 			 * page.
464 			 */
465 			new_npgs = btop(P2ROUNDUP(amp->size, share_sz));
466 			more_pgs = new_npgs - npages;
467 
468 			/*
469 			 * The zone will never be NULL, as a fully created
470 			 * shm always has an owning zone.
471 			 */
472 			zone = sp->shm_perm.ipc_zone;
473 			ASSERT(zone != NULL);
474 			if (anon_resv_zone(ptob(more_pgs), zone) == 0) {
475 				err = ENOMEM;
476 				goto out4;
477 			}
478 
479 			nahp = anon_create(new_npgs, ANON_SLEEP);
480 			ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
481 			(void) anon_copy_ptr(amp->ahp, 0, nahp, 0, npages,
482 			    ANON_SLEEP);
483 			anon_release(amp->ahp, npages);
484 			amp->ahp = nahp;
485 			ASSERT(amp->swresv == ptob(npages));
486 			amp->swresv = amp->size = ptob(new_npgs);
487 			ANON_LOCK_EXIT(&amp->a_rwlock);
488 			npages = new_npgs;
489 		}
490 
491 		sptd->spt_ppa_lckcnt = kmem_zalloc(npages *
492 		    sizeof (*sptd->spt_ppa_lckcnt), KM_SLEEP);
493 		sptd->spt_pcachecnt = 0;
494 		sptd->spt_realsize = ptob(npages);
495 		sptcargs->seg_spt = seg;
496 		return (0);
497 	}
498 
499 	/*
500 	 * get array of pages for each anon slot in amp
501 	 */
502 	if ((err = anon_map_createpages(amp, anon_index, ptob(npages), ppa,
503 	    seg, addr, S_CREATE, cred)) != 0)
504 		goto out4;
505 
506 	mutex_enter(&sp->shm_mlock);
507 
508 	/* May be partially locked, so, count bytes to charge for locking */
509 	for (i = 0; i < npages; i++)
510 		if (ppa[i]->p_lckcnt == 0)
511 			lockedbytes += PAGESIZE;
512 
513 	proj = sp->shm_perm.ipc_proj;
514 
515 	if (lockedbytes > 0) {
516 		mutex_enter(&procp->p_lock);
517 		if (rctl_incr_locked_mem(procp, proj, lockedbytes, 0)) {
518 			mutex_exit(&procp->p_lock);
519 			mutex_exit(&sp->shm_mlock);
520 			for (i = 0; i < npages; i++)
521 				page_unlock(ppa[i]);
522 			err = ENOMEM;
523 			goto out4;
524 		}
525 		mutex_exit(&procp->p_lock);
526 	}
527 
528 	/*
529 	 * addr is initial address corresponding to the first page on ppa list
530 	 */
531 	for (i = 0; i < npages; i++) {
532 		/* attempt to lock all pages */
533 		if (page_pp_lock(ppa[i], 0, 1) == 0) {
534 			/*
535 			 * if unable to lock any page, unlock all
536 			 * of them and return error
537 			 */
538 			for (j = 0; j < i; j++)
539 				page_pp_unlock(ppa[j], 0, 1);
540 			for (i = 0; i < npages; i++)
541 				page_unlock(ppa[i]);
542 			rctl_decr_locked_mem(NULL, proj, lockedbytes, 0);
543 			mutex_exit(&sp->shm_mlock);
544 			err = ENOMEM;
545 			goto out4;
546 		}
547 	}
548 	mutex_exit(&sp->shm_mlock);
549 
550 	/*
551 	 * Some platforms assume that ISM mappings are HAT_LOAD_LOCK
552 	 * for the entire life of the segment. For example platforms
553 	 * that do not support Dynamic Reconfiguration.
554 	 */
555 	hat_flags = HAT_LOAD_SHARE;
556 	if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, NULL))
557 		hat_flags |= HAT_LOAD_LOCK;
558 
559 	/*
560 	 * Load translations one lare page at a time
561 	 * to make sure we don't create mappings bigger than
562 	 * segment's size code in case underlying pages
563 	 * are shared with segvn's segment that uses bigger
564 	 * size code than we do.
565 	 */
566 	pgsz = page_get_pagesize(seg->s_szc);
567 	pgcnt = page_get_pagecnt(seg->s_szc);
568 	for (a = addr, pidx = 0; pidx < npages; a += pgsz, pidx += pgcnt) {
569 		sz = MIN(pgsz, ptob(npages - pidx));
570 		hat_memload_array(seg->s_as->a_hat, a, sz,
571 		    &ppa[pidx], sptd->spt_prot, hat_flags);
572 	}
573 
574 	/*
575 	 * On platforms that do not support HAT_DYNAMIC_ISM_UNMAP,
576 	 * we will leave the pages locked SE_SHARED for the life
577 	 * of the ISM segment. This will prevent any calls to
578 	 * hat_pageunload() on this ISM segment for those platforms.
579 	 */
580 	if (!(hat_flags & HAT_LOAD_LOCK)) {
581 		/*
582 		 * On platforms that support HAT_DYNAMIC_ISM_UNMAP,
583 		 * we no longer need to hold the SE_SHARED lock on the pages,
584 		 * since L_PAGELOCK and F_SOFTLOCK calls will grab the
585 		 * SE_SHARED lock on the pages as necessary.
586 		 */
587 		for (i = 0; i < npages; i++)
588 			page_unlock(ppa[i]);
589 	}
590 	sptd->spt_pcachecnt = 0;
591 	kmem_free(ppa, ((sizeof (page_t *)) * npages));
592 	sptd->spt_realsize = ptob(npages);
593 	atomic_add_long(&spt_used, npages);
594 	sptcargs->seg_spt = seg;
595 	return (0);
596 
597 out4:
598 	seg->s_data = NULL;
599 	kmem_free(vp, sizeof (*vp));
600 	cv_destroy(&sptd->spt_cv);
601 out3:
602 	mutex_destroy(&sptd->spt_lock);
603 	if ((sptcargs->flags & SHM_PAGEABLE) == 0)
604 		kmem_free(ppa, (sizeof (*ppa) * npages));
605 out2:
606 	kmem_free(sptd, sizeof (*sptd));
607 out1:
608 	if ((sptcargs->flags & SHM_PAGEABLE) == 0)
609 		anon_swap_restore(npages);
610 	return (err);
611 }
612 
613 /*ARGSUSED*/
614 void
615 segspt_free_pages(struct seg *seg, caddr_t addr, size_t len)
616 {
617 	struct page 	*pp;
618 	struct spt_data *sptd = (struct spt_data *)seg->s_data;
619 	pgcnt_t		npages;
620 	ulong_t		anon_idx;
621 	struct anon_map *amp;
622 	struct anon 	*ap;
623 	struct vnode 	*vp;
624 	u_offset_t 	off;
625 	uint_t		hat_flags;
626 	int		root = 0;
627 	pgcnt_t		pgs, curnpgs = 0;
628 	page_t		*rootpp;
629 	rctl_qty_t	unlocked_bytes = 0;
630 	kproject_t	*proj;
631 	kshmid_t	*sp;
632 
633 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
634 
635 	len = P2ROUNDUP(len, PAGESIZE);
636 
637 	npages = btop(len);
638 
639 	hat_flags = HAT_UNLOAD_UNLOCK | HAT_UNLOAD_UNMAP;
640 	if ((hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) ||
641 	    (sptd->spt_flags & SHM_PAGEABLE)) {
642 		hat_flags = HAT_UNLOAD_UNMAP;
643 	}
644 
645 	hat_unload(seg->s_as->a_hat, addr, len, hat_flags);
646 
647 	amp = sptd->spt_amp;
648 	if (sptd->spt_flags & SHM_PAGEABLE)
649 		npages = btop(amp->size);
650 
651 	ASSERT(amp != NULL);
652 
653 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
654 		sp = amp->a_sp;
655 		proj = sp->shm_perm.ipc_proj;
656 		mutex_enter(&sp->shm_mlock);
657 	}
658 	for (anon_idx = 0; anon_idx < npages; anon_idx++) {
659 		if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
660 			if ((ap = anon_get_ptr(amp->ahp, anon_idx)) == NULL) {
661 				panic("segspt_free_pages: null app");
662 				/*NOTREACHED*/
663 			}
664 		} else {
665 			if ((ap = anon_get_next_ptr(amp->ahp, &anon_idx))
666 			    == NULL)
667 				continue;
668 		}
669 		ASSERT(ANON_ISBUSY(anon_get_slot(amp->ahp, anon_idx)) == 0);
670 		swap_xlate(ap, &vp, &off);
671 
672 		/*
673 		 * If this platform supports HAT_DYNAMIC_ISM_UNMAP,
674 		 * the pages won't be having SE_SHARED lock at this
675 		 * point.
676 		 *
677 		 * On platforms that do not support HAT_DYNAMIC_ISM_UNMAP,
678 		 * the pages are still held SE_SHARED locked from the
679 		 * original segspt_create()
680 		 *
681 		 * Our goal is to get SE_EXCL lock on each page, remove
682 		 * permanent lock on it and invalidate the page.
683 		 */
684 		if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
685 			if (hat_flags == HAT_UNLOAD_UNMAP)
686 				pp = page_lookup(vp, off, SE_EXCL);
687 			else {
688 				if ((pp = page_find(vp, off)) == NULL) {
689 					panic("segspt_free_pages: "
690 					    "page not locked");
691 					/*NOTREACHED*/
692 				}
693 				if (!page_tryupgrade(pp)) {
694 					page_unlock(pp);
695 					pp = page_lookup(vp, off, SE_EXCL);
696 				}
697 			}
698 			if (pp == NULL) {
699 				panic("segspt_free_pages: "
700 				    "page not in the system");
701 				/*NOTREACHED*/
702 			}
703 			ASSERT(pp->p_lckcnt > 0);
704 			page_pp_unlock(pp, 0, 1);
705 			if (pp->p_lckcnt == 0)
706 				unlocked_bytes += PAGESIZE;
707 		} else {
708 			if ((pp = page_lookup(vp, off, SE_EXCL)) == NULL)
709 				continue;
710 		}
711 		/*
712 		 * It's logical to invalidate the pages here as in most cases
713 		 * these were created by segspt.
714 		 */
715 		if (pp->p_szc != 0) {
716 			if (root == 0) {
717 				ASSERT(curnpgs == 0);
718 				root = 1;
719 				rootpp = pp;
720 				pgs = curnpgs = page_get_pagecnt(pp->p_szc);
721 				ASSERT(pgs > 1);
722 				ASSERT(IS_P2ALIGNED(pgs, pgs));
723 				ASSERT(!(page_pptonum(pp) & (pgs - 1)));
724 				curnpgs--;
725 			} else if ((page_pptonum(pp) & (pgs - 1)) == pgs - 1) {
726 				ASSERT(curnpgs == 1);
727 				ASSERT(page_pptonum(pp) ==
728 				    page_pptonum(rootpp) + (pgs - 1));
729 				page_destroy_pages(rootpp);
730 				root = 0;
731 				curnpgs = 0;
732 			} else {
733 				ASSERT(curnpgs > 1);
734 				ASSERT(page_pptonum(pp) ==
735 				    page_pptonum(rootpp) + (pgs - curnpgs));
736 				curnpgs--;
737 			}
738 		} else {
739 			if (root != 0 || curnpgs != 0) {
740 				panic("segspt_free_pages: bad large page");
741 				/*NOTREACHED*/
742 			}
743 			/*LINTED: constant in conditional context */
744 			VN_DISPOSE(pp, B_INVAL, 0, kcred);
745 		}
746 	}
747 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
748 		if (unlocked_bytes > 0)
749 			rctl_decr_locked_mem(NULL, proj, unlocked_bytes, 0);
750 		mutex_exit(&sp->shm_mlock);
751 	}
752 	if (root != 0 || curnpgs != 0) {
753 		panic("segspt_free_pages: bad large page");
754 		/*NOTREACHED*/
755 	}
756 
757 	/*
758 	 * mark that pages have been released
759 	 */
760 	sptd->spt_realsize = 0;
761 
762 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
763 		atomic_add_long(&spt_used, -npages);
764 		anon_swap_restore(npages);
765 	}
766 }
767 
768 /*
769  * Get memory allocation policy info for specified address in given segment
770  */
771 static lgrp_mem_policy_info_t *
772 segspt_getpolicy(struct seg *seg, caddr_t addr)
773 {
774 	struct anon_map		*amp;
775 	ulong_t			anon_index;
776 	lgrp_mem_policy_info_t	*policy_info;
777 	struct spt_data		*spt_data;
778 
779 	ASSERT(seg != NULL);
780 
781 	/*
782 	 * Get anon_map from segspt
783 	 *
784 	 * Assume that no lock needs to be held on anon_map, since
785 	 * it should be protected by its reference count which must be
786 	 * nonzero for an existing segment
787 	 * Need to grab readers lock on policy tree though
788 	 */
789 	spt_data = (struct spt_data *)seg->s_data;
790 	if (spt_data == NULL)
791 		return (NULL);
792 	amp = spt_data->spt_amp;
793 	ASSERT(amp->refcnt != 0);
794 
795 	/*
796 	 * Get policy info
797 	 *
798 	 * Assume starting anon index of 0
799 	 */
800 	anon_index = seg_page(seg, addr);
801 	policy_info = lgrp_shm_policy_get(amp, anon_index, NULL, 0);
802 
803 	return (policy_info);
804 }
805 
806 /*
807  * DISM only.
808  * Return locked pages over a given range.
809  *
810  * We will cache all DISM locked pages and save the pplist for the
811  * entire segment in the ppa field of the underlying DISM segment structure.
812  * Later, during a call to segspt_reclaim() we will use this ppa array
813  * to page_unlock() all of the pages and then we will free this ppa list.
814  */
815 /*ARGSUSED*/
816 static int
817 segspt_dismpagelock(struct seg *seg, caddr_t addr, size_t len,
818     struct page ***ppp, enum lock_type type, enum seg_rw rw)
819 {
820 	struct  shm_data *shmd = (struct shm_data *)seg->s_data;
821 	struct  seg	*sptseg = shmd->shm_sptseg;
822 	struct  spt_data *sptd = sptseg->s_data;
823 	pgcnt_t pg_idx, npages, tot_npages, npgs;
824 	struct  page **pplist, **pl, **ppa, *pp;
825 	struct  anon_map *amp;
826 	spgcnt_t	an_idx;
827 	int 	ret = ENOTSUP;
828 	uint_t	pl_built = 0;
829 	struct  anon *ap;
830 	struct  vnode *vp;
831 	u_offset_t off;
832 	pgcnt_t claim_availrmem = 0;
833 	uint_t	szc;
834 
835 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
836 
837 	/*
838 	 * We want to lock/unlock the entire ISM segment. Therefore,
839 	 * we will be using the underlying sptseg and it's base address
840 	 * and length for the caching arguments.
841 	 */
842 	ASSERT(sptseg);
843 	ASSERT(sptd);
844 
845 	pg_idx = seg_page(seg, addr);
846 	npages = btopr(len);
847 
848 	/*
849 	 * check if the request is larger than number of pages covered
850 	 * by amp
851 	 */
852 	if (pg_idx + npages > btopr(sptd->spt_amp->size)) {
853 		*ppp = NULL;
854 		return (ENOTSUP);
855 	}
856 
857 	if (type == L_PAGEUNLOCK) {
858 		ASSERT(sptd->spt_ppa != NULL);
859 
860 		seg_pinactive(seg, seg->s_base, sptd->spt_amp->size,
861 		    sptd->spt_ppa, sptd->spt_prot, segspt_reclaim);
862 
863 		/*
864 		 * If someone is blocked while unmapping, we purge
865 		 * segment page cache and thus reclaim pplist synchronously
866 		 * without waiting for seg_pasync_thread. This speeds up
867 		 * unmapping in cases where munmap(2) is called, while
868 		 * raw async i/o is still in progress or where a thread
869 		 * exits on data fault in a multithreaded application.
870 		 */
871 		if (AS_ISUNMAPWAIT(seg->s_as) && (shmd->shm_softlockcnt > 0)) {
872 			segspt_purge(seg);
873 		}
874 		return (0);
875 	} else if (type == L_PAGERECLAIM) {
876 		ASSERT(sptd->spt_ppa != NULL);
877 		(void) segspt_reclaim(seg, seg->s_base, sptd->spt_amp->size,
878 		    sptd->spt_ppa, sptd->spt_prot);
879 		return (0);
880 	}
881 
882 	if (sptd->spt_flags & DISM_PPA_CHANGED) {
883 		segspt_purge(seg);
884 		/*
885 		 * for DISM ppa needs to be rebuild since
886 		 * number of locked pages could be changed
887 		 */
888 		*ppp = NULL;
889 		return (ENOTSUP);
890 	}
891 
892 	/*
893 	 * First try to find pages in segment page cache, without
894 	 * holding the segment lock.
895 	 */
896 	pplist = seg_plookup(seg, seg->s_base, sptd->spt_amp->size,
897 	    sptd->spt_prot);
898 	if (pplist != NULL) {
899 		ASSERT(sptd->spt_ppa != NULL);
900 		ASSERT(sptd->spt_ppa == pplist);
901 		ppa = sptd->spt_ppa;
902 		for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
903 			if (ppa[an_idx] == NULL) {
904 				seg_pinactive(seg, seg->s_base,
905 				    sptd->spt_amp->size, ppa,
906 				    sptd->spt_prot, segspt_reclaim);
907 				*ppp = NULL;
908 				return (ENOTSUP);
909 			}
910 			if ((szc = ppa[an_idx]->p_szc) != 0) {
911 				npgs = page_get_pagecnt(szc);
912 				an_idx = P2ROUNDUP(an_idx + 1, npgs);
913 			} else {
914 				an_idx++;
915 			}
916 		}
917 		/*
918 		 * Since we cache the entire DISM segment, we want to
919 		 * set ppp to point to the first slot that corresponds
920 		 * to the requested addr, i.e. pg_idx.
921 		 */
922 		*ppp = &(sptd->spt_ppa[pg_idx]);
923 		return (0);
924 	}
925 
926 	/* The L_PAGELOCK case... */
927 	mutex_enter(&sptd->spt_lock);
928 	/*
929 	 * try to find pages in segment page cache with mutex
930 	 */
931 	pplist = seg_plookup(seg, seg->s_base, sptd->spt_amp->size,
932 	    sptd->spt_prot);
933 	if (pplist != NULL) {
934 		ASSERT(sptd->spt_ppa != NULL);
935 		ASSERT(sptd->spt_ppa == pplist);
936 		ppa = sptd->spt_ppa;
937 		for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
938 			if (ppa[an_idx] == NULL) {
939 				mutex_exit(&sptd->spt_lock);
940 				seg_pinactive(seg, seg->s_base,
941 				    sptd->spt_amp->size, ppa,
942 				    sptd->spt_prot, segspt_reclaim);
943 				*ppp = NULL;
944 				return (ENOTSUP);
945 			}
946 			if ((szc = ppa[an_idx]->p_szc) != 0) {
947 				npgs = page_get_pagecnt(szc);
948 				an_idx = P2ROUNDUP(an_idx + 1, npgs);
949 			} else {
950 				an_idx++;
951 			}
952 		}
953 		/*
954 		 * Since we cache the entire DISM segment, we want to
955 		 * set ppp to point to the first slot that corresponds
956 		 * to the requested addr, i.e. pg_idx.
957 		 */
958 		mutex_exit(&sptd->spt_lock);
959 		*ppp = &(sptd->spt_ppa[pg_idx]);
960 		return (0);
961 	}
962 	if (seg_pinsert_check(seg, sptd->spt_amp->size, SEGP_FORCE_WIRED) ==
963 	    SEGP_FAIL) {
964 		mutex_exit(&sptd->spt_lock);
965 		*ppp = NULL;
966 		return (ENOTSUP);
967 	}
968 
969 	/*
970 	 * No need to worry about protections because DISM pages are always rw.
971 	 */
972 	pl = pplist = NULL;
973 	amp = sptd->spt_amp;
974 
975 	/*
976 	 * Do we need to build the ppa array?
977 	 */
978 	if (sptd->spt_ppa == NULL) {
979 		pgcnt_t lpg_cnt = 0;
980 
981 		pl_built = 1;
982 		tot_npages = btopr(sptd->spt_amp->size);
983 
984 		ASSERT(sptd->spt_pcachecnt == 0);
985 		pplist = kmem_zalloc(sizeof (page_t *) * tot_npages, KM_SLEEP);
986 		pl = pplist;
987 
988 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
989 		for (an_idx = 0; an_idx < tot_npages; ) {
990 			ap = anon_get_ptr(amp->ahp, an_idx);
991 			/*
992 			 * Cache only mlocked pages. For large pages
993 			 * if one (constituent) page is mlocked
994 			 * all pages for that large page
995 			 * are cached also. This is for quick
996 			 * lookups of ppa array;
997 			 */
998 			if ((ap != NULL) && (lpg_cnt != 0 ||
999 			    (sptd->spt_ppa_lckcnt[an_idx] != 0))) {
1000 
1001 				swap_xlate(ap, &vp, &off);
1002 				pp = page_lookup(vp, off, SE_SHARED);
1003 				ASSERT(pp != NULL);
1004 				if (lpg_cnt == 0) {
1005 					lpg_cnt++;
1006 					/*
1007 					 * For a small page, we are done --
1008 					 * lpg_count is reset to 0 below.
1009 					 *
1010 					 * For a large page, we are guaranteed
1011 					 * to find the anon structures of all
1012 					 * constituent pages and a non-zero
1013 					 * lpg_cnt ensures that we don't test
1014 					 * for mlock for these. We are done
1015 					 * when lpg_count reaches (npgs + 1).
1016 					 * If we are not the first constituent
1017 					 * page, restart at the first one.
1018 					 */
1019 					npgs = page_get_pagecnt(pp->p_szc);
1020 					if (!IS_P2ALIGNED(an_idx, npgs)) {
1021 						an_idx = P2ALIGN(an_idx, npgs);
1022 						page_unlock(pp);
1023 						continue;
1024 					}
1025 				}
1026 				if (++lpg_cnt > npgs)
1027 					lpg_cnt = 0;
1028 
1029 				/*
1030 				 * availrmem is decremented only
1031 				 * for unlocked pages
1032 				 */
1033 				if (sptd->spt_ppa_lckcnt[an_idx] == 0)
1034 					claim_availrmem++;
1035 				pplist[an_idx] = pp;
1036 			}
1037 			an_idx++;
1038 		}
1039 		ANON_LOCK_EXIT(&amp->a_rwlock);
1040 
1041 		mutex_enter(&freemem_lock);
1042 		if (availrmem < tune.t_minarmem + claim_availrmem) {
1043 			mutex_exit(&freemem_lock);
1044 			ret = FC_MAKE_ERR(ENOMEM);
1045 			claim_availrmem = 0;
1046 			goto insert_fail;
1047 		} else {
1048 			availrmem -= claim_availrmem;
1049 		}
1050 		mutex_exit(&freemem_lock);
1051 
1052 		sptd->spt_ppa = pl;
1053 	} else {
1054 		/*
1055 		 * We already have a valid ppa[].
1056 		 */
1057 		pl = sptd->spt_ppa;
1058 	}
1059 
1060 	ASSERT(pl != NULL);
1061 
1062 	ret = seg_pinsert(seg, seg->s_base, sptd->spt_amp->size,
1063 	    pl, sptd->spt_prot, SEGP_FORCE_WIRED | SEGP_ASYNC_FLUSH,
1064 	    segspt_reclaim);
1065 	if (ret == SEGP_FAIL) {
1066 		/*
1067 		 * seg_pinsert failed. We return
1068 		 * ENOTSUP, so that the as_pagelock() code will
1069 		 * then try the slower F_SOFTLOCK path.
1070 		 */
1071 		if (pl_built) {
1072 			/*
1073 			 * No one else has referenced the ppa[].
1074 			 * We created it and we need to destroy it.
1075 			 */
1076 			sptd->spt_ppa = NULL;
1077 		}
1078 		ret = ENOTSUP;
1079 		goto insert_fail;
1080 	}
1081 
1082 	/*
1083 	 * In either case, we increment softlockcnt on the 'real' segment.
1084 	 */
1085 	sptd->spt_pcachecnt++;
1086 	atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), 1);
1087 
1088 	ppa = sptd->spt_ppa;
1089 	for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
1090 		if (ppa[an_idx] == NULL) {
1091 			mutex_exit(&sptd->spt_lock);
1092 			seg_pinactive(seg, seg->s_base, sptd->spt_amp->size,
1093 			    pl, sptd->spt_prot, segspt_reclaim);
1094 			*ppp = NULL;
1095 			return (ENOTSUP);
1096 		}
1097 		if ((szc = ppa[an_idx]->p_szc) != 0) {
1098 			npgs = page_get_pagecnt(szc);
1099 			an_idx = P2ROUNDUP(an_idx + 1, npgs);
1100 		} else {
1101 			an_idx++;
1102 		}
1103 	}
1104 	/*
1105 	 * We can now drop the sptd->spt_lock since the ppa[]
1106 	 * exists and he have incremented pacachecnt.
1107 	 */
1108 	mutex_exit(&sptd->spt_lock);
1109 
1110 	/*
1111 	 * Since we cache the entire segment, we want to
1112 	 * set ppp to point to the first slot that corresponds
1113 	 * to the requested addr, i.e. pg_idx.
1114 	 */
1115 	*ppp = &(sptd->spt_ppa[pg_idx]);
1116 	return (ret);
1117 
1118 insert_fail:
1119 	/*
1120 	 * We will only reach this code if we tried and failed.
1121 	 *
1122 	 * And we can drop the lock on the dummy seg, once we've failed
1123 	 * to set up a new ppa[].
1124 	 */
1125 	mutex_exit(&sptd->spt_lock);
1126 
1127 	if (pl_built) {
1128 		mutex_enter(&freemem_lock);
1129 		availrmem += claim_availrmem;
1130 		mutex_exit(&freemem_lock);
1131 
1132 		/*
1133 		 * We created pl and we need to destroy it.
1134 		 */
1135 		pplist = pl;
1136 		for (an_idx = 0; an_idx < tot_npages; an_idx++) {
1137 			if (pplist[an_idx] != NULL)
1138 				page_unlock(pplist[an_idx]);
1139 		}
1140 		kmem_free(pl, sizeof (page_t *) * tot_npages);
1141 	}
1142 
1143 	if (shmd->shm_softlockcnt <= 0) {
1144 		if (AS_ISUNMAPWAIT(seg->s_as)) {
1145 			mutex_enter(&seg->s_as->a_contents);
1146 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1147 				AS_CLRUNMAPWAIT(seg->s_as);
1148 				cv_broadcast(&seg->s_as->a_cv);
1149 			}
1150 			mutex_exit(&seg->s_as->a_contents);
1151 		}
1152 	}
1153 	*ppp = NULL;
1154 	return (ret);
1155 }
1156 
1157 
1158 
1159 /*
1160  * return locked pages over a given range.
1161  *
1162  * We will cache the entire ISM segment and save the pplist for the
1163  * entire segment in the ppa field of the underlying ISM segment structure.
1164  * Later, during a call to segspt_reclaim() we will use this ppa array
1165  * to page_unlock() all of the pages and then we will free this ppa list.
1166  */
1167 /*ARGSUSED*/
1168 static int
1169 segspt_shmpagelock(struct seg *seg, caddr_t addr, size_t len,
1170     struct page ***ppp, enum lock_type type, enum seg_rw rw)
1171 {
1172 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
1173 	struct seg	*sptseg = shmd->shm_sptseg;
1174 	struct spt_data *sptd = sptseg->s_data;
1175 	pgcnt_t np, page_index, npages;
1176 	caddr_t a, spt_base;
1177 	struct page **pplist, **pl, *pp;
1178 	struct anon_map *amp;
1179 	ulong_t anon_index;
1180 	int ret = ENOTSUP;
1181 	uint_t	pl_built = 0;
1182 	struct anon *ap;
1183 	struct vnode *vp;
1184 	u_offset_t off;
1185 
1186 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1187 
1188 	/*
1189 	 * We want to lock/unlock the entire ISM segment. Therefore,
1190 	 * we will be using the underlying sptseg and it's base address
1191 	 * and length for the caching arguments.
1192 	 */
1193 	ASSERT(sptseg);
1194 	ASSERT(sptd);
1195 
1196 	if (sptd->spt_flags & SHM_PAGEABLE) {
1197 		return (segspt_dismpagelock(seg, addr, len, ppp, type, rw));
1198 	}
1199 
1200 	page_index = seg_page(seg, addr);
1201 	npages = btopr(len);
1202 
1203 	/*
1204 	 * check if the request is larger than number of pages covered
1205 	 * by amp
1206 	 */
1207 	if (page_index + npages > btopr(sptd->spt_amp->size)) {
1208 		*ppp = NULL;
1209 		return (ENOTSUP);
1210 	}
1211 
1212 	if (type == L_PAGEUNLOCK) {
1213 
1214 		ASSERT(sptd->spt_ppa != NULL);
1215 
1216 		seg_pinactive(seg, seg->s_base, sptd->spt_amp->size,
1217 		    sptd->spt_ppa, sptd->spt_prot, segspt_reclaim);
1218 
1219 		/*
1220 		 * If someone is blocked while unmapping, we purge
1221 		 * segment page cache and thus reclaim pplist synchronously
1222 		 * without waiting for seg_pasync_thread. This speeds up
1223 		 * unmapping in cases where munmap(2) is called, while
1224 		 * raw async i/o is still in progress or where a thread
1225 		 * exits on data fault in a multithreaded application.
1226 		 */
1227 		if (AS_ISUNMAPWAIT(seg->s_as) && (shmd->shm_softlockcnt > 0)) {
1228 			segspt_purge(seg);
1229 		}
1230 		return (0);
1231 	} else if (type == L_PAGERECLAIM) {
1232 		ASSERT(sptd->spt_ppa != NULL);
1233 
1234 		(void) segspt_reclaim(seg, seg->s_base, sptd->spt_amp->size,
1235 		    sptd->spt_ppa, sptd->spt_prot);
1236 		return (0);
1237 	}
1238 
1239 	/*
1240 	 * First try to find pages in segment page cache, without
1241 	 * holding the segment lock.
1242 	 */
1243 	pplist = seg_plookup(seg, seg->s_base, sptd->spt_amp->size,
1244 	    sptd->spt_prot);
1245 	if (pplist != NULL) {
1246 		ASSERT(sptd->spt_ppa == pplist);
1247 		ASSERT(sptd->spt_ppa[page_index]);
1248 		/*
1249 		 * Since we cache the entire ISM segment, we want to
1250 		 * set ppp to point to the first slot that corresponds
1251 		 * to the requested addr, i.e. page_index.
1252 		 */
1253 		*ppp = &(sptd->spt_ppa[page_index]);
1254 		return (0);
1255 	}
1256 
1257 	/* The L_PAGELOCK case... */
1258 	mutex_enter(&sptd->spt_lock);
1259 
1260 	/*
1261 	 * try to find pages in segment page cache
1262 	 */
1263 	pplist = seg_plookup(seg, seg->s_base, sptd->spt_amp->size,
1264 	    sptd->spt_prot);
1265 	if (pplist != NULL) {
1266 		ASSERT(sptd->spt_ppa == pplist);
1267 		/*
1268 		 * Since we cache the entire segment, we want to
1269 		 * set ppp to point to the first slot that corresponds
1270 		 * to the requested addr, i.e. page_index.
1271 		 */
1272 		mutex_exit(&sptd->spt_lock);
1273 		*ppp = &(sptd->spt_ppa[page_index]);
1274 		return (0);
1275 	}
1276 
1277 	if (seg_pinsert_check(seg, sptd->spt_amp->size, SEGP_FORCE_WIRED) ==
1278 	    SEGP_FAIL) {
1279 		mutex_exit(&sptd->spt_lock);
1280 		*ppp = NULL;
1281 		return (ENOTSUP);
1282 	}
1283 
1284 	/*
1285 	 * No need to worry about protections because ISM pages
1286 	 * are always rw.
1287 	 */
1288 	pl = pplist = NULL;
1289 
1290 	/*
1291 	 * Do we need to build the ppa array?
1292 	 */
1293 	if (sptd->spt_ppa == NULL) {
1294 		ASSERT(sptd->spt_ppa == pplist);
1295 
1296 		spt_base = sptseg->s_base;
1297 		pl_built = 1;
1298 
1299 		/*
1300 		 * availrmem is decremented once during anon_swap_adjust()
1301 		 * and is incremented during the anon_unresv(), which is
1302 		 * called from shm_rm_amp() when the segment is destroyed.
1303 		 */
1304 		amp = sptd->spt_amp;
1305 		ASSERT(amp != NULL);
1306 
1307 		/* pcachecnt is protected by sptd->spt_lock */
1308 		ASSERT(sptd->spt_pcachecnt == 0);
1309 		pplist = kmem_zalloc(sizeof (page_t *)
1310 		    * btopr(sptd->spt_amp->size), KM_SLEEP);
1311 		pl = pplist;
1312 
1313 		anon_index = seg_page(sptseg, spt_base);
1314 
1315 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
1316 		for (a = spt_base; a < (spt_base + sptd->spt_amp->size);
1317 		    a += PAGESIZE, anon_index++, pplist++) {
1318 			ap = anon_get_ptr(amp->ahp, anon_index);
1319 			ASSERT(ap != NULL);
1320 			swap_xlate(ap, &vp, &off);
1321 			pp = page_lookup(vp, off, SE_SHARED);
1322 			ASSERT(pp != NULL);
1323 			*pplist = pp;
1324 		}
1325 		ANON_LOCK_EXIT(&amp->a_rwlock);
1326 
1327 		if (a < (spt_base + sptd->spt_amp->size)) {
1328 			ret = ENOTSUP;
1329 			goto insert_fail;
1330 		}
1331 		sptd->spt_ppa = pl;
1332 	} else {
1333 		/*
1334 		 * We already have a valid ppa[].
1335 		 */
1336 		pl = sptd->spt_ppa;
1337 	}
1338 
1339 	ASSERT(pl != NULL);
1340 
1341 	ret = seg_pinsert(seg, seg->s_base, sptd->spt_amp->size,
1342 	    pl, sptd->spt_prot, SEGP_FORCE_WIRED, segspt_reclaim);
1343 	if (ret == SEGP_FAIL) {
1344 		/*
1345 		 * seg_pinsert failed. We return
1346 		 * ENOTSUP, so that the as_pagelock() code will
1347 		 * then try the slower F_SOFTLOCK path.
1348 		 */
1349 		if (pl_built) {
1350 			/*
1351 			 * No one else has referenced the ppa[].
1352 			 * We created it and we need to destroy it.
1353 			 */
1354 			sptd->spt_ppa = NULL;
1355 		}
1356 		ret = ENOTSUP;
1357 		goto insert_fail;
1358 	}
1359 
1360 	/*
1361 	 * In either case, we increment softlockcnt on the 'real' segment.
1362 	 */
1363 	sptd->spt_pcachecnt++;
1364 	atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), 1);
1365 
1366 	/*
1367 	 * We can now drop the sptd->spt_lock since the ppa[]
1368 	 * exists and he have incremented pacachecnt.
1369 	 */
1370 	mutex_exit(&sptd->spt_lock);
1371 
1372 	/*
1373 	 * Since we cache the entire segment, we want to
1374 	 * set ppp to point to the first slot that corresponds
1375 	 * to the requested addr, i.e. page_index.
1376 	 */
1377 	*ppp = &(sptd->spt_ppa[page_index]);
1378 	return (ret);
1379 
1380 insert_fail:
1381 	/*
1382 	 * We will only reach this code if we tried and failed.
1383 	 *
1384 	 * And we can drop the lock on the dummy seg, once we've failed
1385 	 * to set up a new ppa[].
1386 	 */
1387 	mutex_exit(&sptd->spt_lock);
1388 
1389 	if (pl_built) {
1390 		/*
1391 		 * We created pl and we need to destroy it.
1392 		 */
1393 		pplist = pl;
1394 		np = (((uintptr_t)(a - spt_base)) >> PAGESHIFT);
1395 		while (np) {
1396 			page_unlock(*pplist);
1397 			np--;
1398 			pplist++;
1399 		}
1400 		kmem_free(pl, sizeof (page_t *) * btopr(sptd->spt_amp->size));
1401 	}
1402 	if (shmd->shm_softlockcnt <= 0) {
1403 		if (AS_ISUNMAPWAIT(seg->s_as)) {
1404 			mutex_enter(&seg->s_as->a_contents);
1405 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1406 				AS_CLRUNMAPWAIT(seg->s_as);
1407 				cv_broadcast(&seg->s_as->a_cv);
1408 			}
1409 			mutex_exit(&seg->s_as->a_contents);
1410 		}
1411 	}
1412 	*ppp = NULL;
1413 	return (ret);
1414 }
1415 
1416 /*
1417  * purge any cached pages in the I/O page cache
1418  */
1419 static void
1420 segspt_purge(struct seg *seg)
1421 {
1422 	seg_ppurge(seg);
1423 }
1424 
1425 static int
1426 segspt_reclaim(struct seg *seg, caddr_t addr, size_t len, struct page **pplist,
1427 	enum seg_rw rw)
1428 {
1429 	struct	shm_data *shmd = (struct shm_data *)seg->s_data;
1430 	struct	seg	*sptseg;
1431 	struct	spt_data *sptd;
1432 	pgcnt_t npages, i, free_availrmem = 0;
1433 	int	done = 0;
1434 
1435 #ifdef lint
1436 	addr = addr;
1437 #endif
1438 	sptseg = shmd->shm_sptseg;
1439 	sptd = sptseg->s_data;
1440 	npages = (len >> PAGESHIFT);
1441 	ASSERT(npages);
1442 	ASSERT(sptd->spt_pcachecnt != 0);
1443 	ASSERT(sptd->spt_ppa == pplist);
1444 	ASSERT(npages == btopr(sptd->spt_amp->size));
1445 	/*
1446 	 * Acquire the lock on the dummy seg and destroy the
1447 	 * ppa array IF this is the last pcachecnt.
1448 	 */
1449 	mutex_enter(&sptd->spt_lock);
1450 	if (--sptd->spt_pcachecnt == 0) {
1451 		for (i = 0; i < npages; i++) {
1452 			if (pplist[i] == NULL) {
1453 				continue;
1454 			}
1455 			if (rw == S_WRITE) {
1456 				hat_setrefmod(pplist[i]);
1457 			} else {
1458 				hat_setref(pplist[i]);
1459 			}
1460 			if ((sptd->spt_flags & SHM_PAGEABLE) &&
1461 			    (sptd->spt_ppa_lckcnt[i] == 0))
1462 				free_availrmem++;
1463 			page_unlock(pplist[i]);
1464 		}
1465 		if (sptd->spt_flags & SHM_PAGEABLE) {
1466 			mutex_enter(&freemem_lock);
1467 			availrmem += free_availrmem;
1468 			mutex_exit(&freemem_lock);
1469 		}
1470 		/*
1471 		 * Since we want to cach/uncache the entire ISM segment,
1472 		 * we will track the pplist in a segspt specific field
1473 		 * ppa, that is initialized at the time we add an entry to
1474 		 * the cache.
1475 		 */
1476 		ASSERT(sptd->spt_pcachecnt == 0);
1477 		kmem_free(pplist, sizeof (page_t *) * npages);
1478 		sptd->spt_ppa = NULL;
1479 		sptd->spt_flags &= ~DISM_PPA_CHANGED;
1480 		sptd->spt_gen++;
1481 		cv_broadcast(&sptd->spt_cv);
1482 		done = 1;
1483 	}
1484 	mutex_exit(&sptd->spt_lock);
1485 	/*
1486 	 * Now decrement softlockcnt.
1487 	 */
1488 	atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), -1);
1489 
1490 	if (shmd->shm_softlockcnt <= 0) {
1491 		if (AS_ISUNMAPWAIT(seg->s_as)) {
1492 			mutex_enter(&seg->s_as->a_contents);
1493 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1494 				AS_CLRUNMAPWAIT(seg->s_as);
1495 				cv_broadcast(&seg->s_as->a_cv);
1496 			}
1497 			mutex_exit(&seg->s_as->a_contents);
1498 		}
1499 	}
1500 	return (done);
1501 }
1502 
1503 /*
1504  * Do a F_SOFTUNLOCK call over the range requested.
1505  * The range must have already been F_SOFTLOCK'ed.
1506  *
1507  * The calls to acquire and release the anon map lock mutex were
1508  * removed in order to avoid a deadly embrace during a DR
1509  * memory delete operation.  (Eg. DR blocks while waiting for a
1510  * exclusive lock on a page that is being used for kaio; the
1511  * thread that will complete the kaio and call segspt_softunlock
1512  * blocks on the anon map lock; another thread holding the anon
1513  * map lock blocks on another page lock via the segspt_shmfault
1514  * -> page_lookup -> page_lookup_create -> page_lock_es code flow.)
1515  *
1516  * The appropriateness of the removal is based upon the following:
1517  * 1. If we are holding a segment's reader lock and the page is held
1518  * shared, then the corresponding element in anonmap which points to
1519  * anon struct cannot change and there is no need to acquire the
1520  * anonymous map lock.
1521  * 2. Threads in segspt_softunlock have a reader lock on the segment
1522  * and already have the shared page lock, so we are guaranteed that
1523  * the anon map slot cannot change and therefore can call anon_get_ptr()
1524  * without grabbing the anonymous map lock.
1525  * 3. Threads that softlock a shared page break copy-on-write, even if
1526  * its a read.  Thus cow faults can be ignored with respect to soft
1527  * unlocking, since the breaking of cow means that the anon slot(s) will
1528  * not be shared.
1529  */
1530 static void
1531 segspt_softunlock(struct seg *seg, caddr_t sptseg_addr,
1532 	size_t len, enum seg_rw rw)
1533 {
1534 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
1535 	struct seg	*sptseg;
1536 	struct spt_data *sptd;
1537 	page_t *pp;
1538 	caddr_t adr;
1539 	struct vnode *vp;
1540 	u_offset_t offset;
1541 	ulong_t anon_index;
1542 	struct anon_map *amp;		/* XXX - for locknest */
1543 	struct anon *ap = NULL;
1544 	pgcnt_t npages;
1545 
1546 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1547 
1548 	sptseg = shmd->shm_sptseg;
1549 	sptd = sptseg->s_data;
1550 
1551 	/*
1552 	 * Some platforms assume that ISM mappings are HAT_LOAD_LOCK
1553 	 * and therefore their pages are SE_SHARED locked
1554 	 * for the entire life of the segment.
1555 	 */
1556 	if ((!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) &&
1557 	    ((sptd->spt_flags & SHM_PAGEABLE) == 0)) {
1558 		goto softlock_decrement;
1559 	}
1560 
1561 	/*
1562 	 * Any thread is free to do a page_find and
1563 	 * page_unlock() on the pages within this seg.
1564 	 *
1565 	 * We are already holding the as->a_lock on the user's
1566 	 * real segment, but we need to hold the a_lock on the
1567 	 * underlying dummy as. This is mostly to satisfy the
1568 	 * underlying HAT layer.
1569 	 */
1570 	AS_LOCK_ENTER(sptseg->s_as, &sptseg->s_as->a_lock, RW_READER);
1571 	hat_unlock(sptseg->s_as->a_hat, sptseg_addr, len);
1572 	AS_LOCK_EXIT(sptseg->s_as, &sptseg->s_as->a_lock);
1573 
1574 	amp = sptd->spt_amp;
1575 	ASSERT(amp != NULL);
1576 	anon_index = seg_page(sptseg, sptseg_addr);
1577 
1578 	for (adr = sptseg_addr; adr < sptseg_addr + len; adr += PAGESIZE) {
1579 		ap = anon_get_ptr(amp->ahp, anon_index++);
1580 		ASSERT(ap != NULL);
1581 		swap_xlate(ap, &vp, &offset);
1582 
1583 		/*
1584 		 * Use page_find() instead of page_lookup() to
1585 		 * find the page since we know that it has a
1586 		 * "shared" lock.
1587 		 */
1588 		pp = page_find(vp, offset);
1589 		ASSERT(ap == anon_get_ptr(amp->ahp, anon_index - 1));
1590 		if (pp == NULL) {
1591 			panic("segspt_softunlock: "
1592 			    "addr %p, ap %p, vp %p, off %llx",
1593 			    (void *)adr, (void *)ap, (void *)vp, offset);
1594 			/*NOTREACHED*/
1595 		}
1596 
1597 		if (rw == S_WRITE) {
1598 			hat_setrefmod(pp);
1599 		} else if (rw != S_OTHER) {
1600 			hat_setref(pp);
1601 		}
1602 		page_unlock(pp);
1603 	}
1604 
1605 softlock_decrement:
1606 	npages = btopr(len);
1607 	atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), -npages);
1608 	if (shmd->shm_softlockcnt == 0) {
1609 		/*
1610 		 * All SOFTLOCKS are gone. Wakeup any waiting
1611 		 * unmappers so they can try again to unmap.
1612 		 * Check for waiters first without the mutex
1613 		 * held so we don't always grab the mutex on
1614 		 * softunlocks.
1615 		 */
1616 		if (AS_ISUNMAPWAIT(seg->s_as)) {
1617 			mutex_enter(&seg->s_as->a_contents);
1618 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1619 				AS_CLRUNMAPWAIT(seg->s_as);
1620 				cv_broadcast(&seg->s_as->a_cv);
1621 			}
1622 			mutex_exit(&seg->s_as->a_contents);
1623 		}
1624 	}
1625 }
1626 
1627 int
1628 segspt_shmattach(struct seg *seg, caddr_t *argsp)
1629 {
1630 	struct shm_data *shmd_arg = (struct shm_data *)argsp;
1631 	struct shm_data *shmd;
1632 	struct anon_map *shm_amp = shmd_arg->shm_amp;
1633 	struct spt_data *sptd;
1634 	int error = 0;
1635 
1636 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
1637 
1638 	shmd = kmem_zalloc((sizeof (*shmd)), KM_NOSLEEP);
1639 	if (shmd == NULL)
1640 		return (ENOMEM);
1641 
1642 	shmd->shm_sptas = shmd_arg->shm_sptas;
1643 	shmd->shm_amp = shm_amp;
1644 	shmd->shm_sptseg = shmd_arg->shm_sptseg;
1645 
1646 	(void) lgrp_shm_policy_set(LGRP_MEM_POLICY_DEFAULT, shm_amp, 0,
1647 	    NULL, 0, seg->s_size);
1648 
1649 	seg->s_data = (void *)shmd;
1650 	seg->s_ops = &segspt_shmops;
1651 	seg->s_szc = shmd->shm_sptseg->s_szc;
1652 	sptd = shmd->shm_sptseg->s_data;
1653 
1654 	if (sptd->spt_flags & SHM_PAGEABLE) {
1655 		if ((shmd->shm_vpage = kmem_zalloc(btopr(shm_amp->size),
1656 		    KM_NOSLEEP)) == NULL) {
1657 			seg->s_data = (void *)NULL;
1658 			kmem_free(shmd, (sizeof (*shmd)));
1659 			return (ENOMEM);
1660 		}
1661 		shmd->shm_lckpgs = 0;
1662 		if (hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
1663 			if ((error = hat_share(seg->s_as->a_hat, seg->s_base,
1664 			    shmd_arg->shm_sptas->a_hat, SEGSPTADDR,
1665 			    seg->s_size, seg->s_szc)) != 0) {
1666 				kmem_free(shmd->shm_vpage,
1667 				    btopr(shm_amp->size));
1668 			}
1669 		}
1670 	} else {
1671 		error = hat_share(seg->s_as->a_hat, seg->s_base,
1672 		    shmd_arg->shm_sptas->a_hat, SEGSPTADDR,
1673 		    seg->s_size, seg->s_szc);
1674 	}
1675 	if (error) {
1676 		seg->s_szc = 0;
1677 		seg->s_data = (void *)NULL;
1678 		kmem_free(shmd, (sizeof (*shmd)));
1679 	} else {
1680 		ANON_LOCK_ENTER(&shm_amp->a_rwlock, RW_WRITER);
1681 		shm_amp->refcnt++;
1682 		ANON_LOCK_EXIT(&shm_amp->a_rwlock);
1683 	}
1684 	return (error);
1685 }
1686 
1687 int
1688 segspt_shmunmap(struct seg *seg, caddr_t raddr, size_t ssize)
1689 {
1690 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
1691 	int reclaim = 1;
1692 
1693 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
1694 retry:
1695 	if (shmd->shm_softlockcnt > 0) {
1696 		if (reclaim == 1) {
1697 			segspt_purge(seg);
1698 			reclaim = 0;
1699 			goto retry;
1700 		}
1701 		return (EAGAIN);
1702 	}
1703 
1704 	if (ssize != seg->s_size) {
1705 #ifdef DEBUG
1706 		cmn_err(CE_WARN, "Incompatible ssize %lx s_size %lx\n",
1707 		    ssize, seg->s_size);
1708 #endif
1709 		return (EINVAL);
1710 	}
1711 
1712 	(void) segspt_shmlockop(seg, raddr, shmd->shm_amp->size, 0, MC_UNLOCK,
1713 	    NULL, 0);
1714 	hat_unshare(seg->s_as->a_hat, raddr, ssize, seg->s_szc);
1715 
1716 	seg_free(seg);
1717 
1718 	return (0);
1719 }
1720 
1721 void
1722 segspt_shmfree(struct seg *seg)
1723 {
1724 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
1725 	struct anon_map *shm_amp = shmd->shm_amp;
1726 
1727 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
1728 
1729 	(void) segspt_shmlockop(seg, seg->s_base, shm_amp->size, 0,
1730 	    MC_UNLOCK, NULL, 0);
1731 
1732 	/*
1733 	 * Need to increment refcnt when attaching
1734 	 * and decrement when detaching because of dup().
1735 	 */
1736 	ANON_LOCK_ENTER(&shm_amp->a_rwlock, RW_WRITER);
1737 	shm_amp->refcnt--;
1738 	ANON_LOCK_EXIT(&shm_amp->a_rwlock);
1739 
1740 	if (shmd->shm_vpage) {	/* only for DISM */
1741 		kmem_free(shmd->shm_vpage, btopr(shm_amp->size));
1742 		shmd->shm_vpage = NULL;
1743 	}
1744 	kmem_free(shmd, sizeof (*shmd));
1745 }
1746 
1747 /*ARGSUSED*/
1748 int
1749 segspt_shmsetprot(struct seg *seg, caddr_t addr, size_t len, uint_t prot)
1750 {
1751 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1752 
1753 	/*
1754 	 * Shared page table is more than shared mapping.
1755 	 *  Individual process sharing page tables can't change prot
1756 	 *  because there is only one set of page tables.
1757 	 *  This will be allowed after private page table is
1758 	 *  supported.
1759 	 */
1760 /* need to return correct status error? */
1761 	return (0);
1762 }
1763 
1764 
1765 faultcode_t
1766 segspt_dismfault(struct hat *hat, struct seg *seg, caddr_t addr,
1767     size_t len, enum fault_type type, enum seg_rw rw)
1768 {
1769 	struct  shm_data 	*shmd = (struct shm_data *)seg->s_data;
1770 	struct  seg		*sptseg = shmd->shm_sptseg;
1771 	struct  as		*curspt = shmd->shm_sptas;
1772 	struct  spt_data 	*sptd = sptseg->s_data;
1773 	pgcnt_t npages;
1774 	size_t  size;
1775 	caddr_t segspt_addr, shm_addr;
1776 	page_t  **ppa;
1777 	int	i;
1778 	ulong_t an_idx = 0;
1779 	int	err = 0;
1780 	int	dyn_ism_unmap = hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0);
1781 	size_t	pgsz;
1782 	pgcnt_t	pgcnt;
1783 	caddr_t	a;
1784 	pgcnt_t	pidx;
1785 
1786 #ifdef lint
1787 	hat = hat;
1788 #endif
1789 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1790 
1791 	/*
1792 	 * Because of the way spt is implemented
1793 	 * the realsize of the segment does not have to be
1794 	 * equal to the segment size itself. The segment size is
1795 	 * often in multiples of a page size larger than PAGESIZE.
1796 	 * The realsize is rounded up to the nearest PAGESIZE
1797 	 * based on what the user requested. This is a bit of
1798 	 * ungliness that is historical but not easily fixed
1799 	 * without re-designing the higher levels of ISM.
1800 	 */
1801 	ASSERT(addr >= seg->s_base);
1802 	if (((addr + len) - seg->s_base) > sptd->spt_realsize)
1803 		return (FC_NOMAP);
1804 	/*
1805 	 * For all of the following cases except F_PROT, we need to
1806 	 * make any necessary adjustments to addr and len
1807 	 * and get all of the necessary page_t's into an array called ppa[].
1808 	 *
1809 	 * The code in shmat() forces base addr and len of ISM segment
1810 	 * to be aligned to largest page size supported. Therefore,
1811 	 * we are able to handle F_SOFTLOCK and F_INVAL calls in "large
1812 	 * pagesize" chunks. We want to make sure that we HAT_LOAD_LOCK
1813 	 * in large pagesize chunks, or else we will screw up the HAT
1814 	 * layer by calling hat_memload_array() with differing page sizes
1815 	 * over a given virtual range.
1816 	 */
1817 	pgsz = page_get_pagesize(sptseg->s_szc);
1818 	pgcnt = page_get_pagecnt(sptseg->s_szc);
1819 	shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), pgsz);
1820 	size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)), pgsz);
1821 	npages = btopr(size);
1822 
1823 	/*
1824 	 * Now we need to convert from addr in segshm to addr in segspt.
1825 	 */
1826 	an_idx = seg_page(seg, shm_addr);
1827 	segspt_addr = sptseg->s_base + ptob(an_idx);
1828 
1829 	ASSERT((segspt_addr + ptob(npages)) <=
1830 	    (sptseg->s_base + sptd->spt_realsize));
1831 	ASSERT(segspt_addr < (sptseg->s_base + sptseg->s_size));
1832 
1833 	switch (type) {
1834 
1835 	case F_SOFTLOCK:
1836 
1837 		mutex_enter(&freemem_lock);
1838 		if (availrmem < tune.t_minarmem + npages) {
1839 			mutex_exit(&freemem_lock);
1840 			return (FC_MAKE_ERR(ENOMEM));
1841 		} else {
1842 			availrmem -= npages;
1843 		}
1844 		mutex_exit(&freemem_lock);
1845 		atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), npages);
1846 		/*
1847 		 * Fall through to the F_INVAL case to load up the hat layer
1848 		 * entries with the HAT_LOAD_LOCK flag.
1849 		 */
1850 		/* FALLTHRU */
1851 	case F_INVAL:
1852 
1853 		if ((rw == S_EXEC) && !(sptd->spt_prot & PROT_EXEC))
1854 			return (FC_NOMAP);
1855 
1856 		ppa = kmem_zalloc(npages * sizeof (page_t *), KM_SLEEP);
1857 
1858 		err = spt_anon_getpages(sptseg, segspt_addr, size, ppa);
1859 		if (err != 0) {
1860 			if (type == F_SOFTLOCK) {
1861 				mutex_enter(&freemem_lock);
1862 				availrmem += npages;
1863 				mutex_exit(&freemem_lock);
1864 				atomic_add_long((ulong_t *)(
1865 				    &(shmd->shm_softlockcnt)), -npages);
1866 			}
1867 			goto dism_err;
1868 		}
1869 		AS_LOCK_ENTER(sptseg->s_as, &sptseg->s_as->a_lock, RW_READER);
1870 		a = segspt_addr;
1871 		pidx = 0;
1872 		if (type == F_SOFTLOCK) {
1873 
1874 			/*
1875 			 * Load up the translation keeping it
1876 			 * locked and don't unlock the page.
1877 			 */
1878 			for (; pidx < npages; a += pgsz, pidx += pgcnt) {
1879 				hat_memload_array(sptseg->s_as->a_hat,
1880 				    a, pgsz, &ppa[pidx], sptd->spt_prot,
1881 				    HAT_LOAD_LOCK | HAT_LOAD_SHARE);
1882 			}
1883 		} else {
1884 			if (hat == seg->s_as->a_hat) {
1885 
1886 				/*
1887 				 * Migrate pages marked for migration
1888 				 */
1889 				if (lgrp_optimizations())
1890 					page_migrate(seg, shm_addr, ppa,
1891 					    npages);
1892 
1893 				/* CPU HAT */
1894 				for (; pidx < npages;
1895 				    a += pgsz, pidx += pgcnt) {
1896 					hat_memload_array(sptseg->s_as->a_hat,
1897 					    a, pgsz, &ppa[pidx],
1898 					    sptd->spt_prot,
1899 					    HAT_LOAD_SHARE);
1900 				}
1901 			} else {
1902 				/* XHAT. Pass real address */
1903 				hat_memload_array(hat, shm_addr,
1904 				    size, ppa, sptd->spt_prot, HAT_LOAD_SHARE);
1905 			}
1906 
1907 			/*
1908 			 * And now drop the SE_SHARED lock(s).
1909 			 */
1910 			if (dyn_ism_unmap) {
1911 				for (i = 0; i < npages; i++) {
1912 					page_unlock(ppa[i]);
1913 				}
1914 			}
1915 		}
1916 
1917 		if (!dyn_ism_unmap) {
1918 			if (hat_share(seg->s_as->a_hat, shm_addr,
1919 			    curspt->a_hat, segspt_addr, ptob(npages),
1920 			    seg->s_szc) != 0) {
1921 				panic("hat_share err in DISM fault");
1922 				/* NOTREACHED */
1923 			}
1924 			if (type == F_INVAL) {
1925 				for (i = 0; i < npages; i++) {
1926 					page_unlock(ppa[i]);
1927 				}
1928 			}
1929 		}
1930 		AS_LOCK_EXIT(sptseg->s_as, &sptseg->s_as->a_lock);
1931 dism_err:
1932 		kmem_free(ppa, npages * sizeof (page_t *));
1933 		return (err);
1934 
1935 	case F_SOFTUNLOCK:
1936 
1937 		mutex_enter(&freemem_lock);
1938 		availrmem += npages;
1939 		mutex_exit(&freemem_lock);
1940 
1941 		/*
1942 		 * This is a bit ugly, we pass in the real seg pointer,
1943 		 * but the segspt_addr is the virtual address within the
1944 		 * dummy seg.
1945 		 */
1946 		segspt_softunlock(seg, segspt_addr, size, rw);
1947 		return (0);
1948 
1949 	case F_PROT:
1950 
1951 		/*
1952 		 * This takes care of the unusual case where a user
1953 		 * allocates a stack in shared memory and a register
1954 		 * window overflow is written to that stack page before
1955 		 * it is otherwise modified.
1956 		 *
1957 		 * We can get away with this because ISM segments are
1958 		 * always rw. Other than this unusual case, there
1959 		 * should be no instances of protection violations.
1960 		 */
1961 		return (0);
1962 
1963 	default:
1964 #ifdef DEBUG
1965 		panic("segspt_dismfault default type?");
1966 #else
1967 		return (FC_NOMAP);
1968 #endif
1969 	}
1970 }
1971 
1972 
1973 faultcode_t
1974 segspt_shmfault(struct hat *hat, struct seg *seg, caddr_t addr,
1975     size_t len, enum fault_type type, enum seg_rw rw)
1976 {
1977 	struct shm_data 	*shmd = (struct shm_data *)seg->s_data;
1978 	struct seg		*sptseg = shmd->shm_sptseg;
1979 	struct as		*curspt = shmd->shm_sptas;
1980 	struct spt_data 	*sptd   = sptseg->s_data;
1981 	pgcnt_t npages;
1982 	size_t size;
1983 	caddr_t sptseg_addr, shm_addr;
1984 	page_t *pp, **ppa;
1985 	int	i;
1986 	u_offset_t offset;
1987 	ulong_t anon_index = 0;
1988 	struct vnode *vp;
1989 	struct anon_map *amp;		/* XXX - for locknest */
1990 	struct anon *ap = NULL;
1991 	size_t		pgsz;
1992 	pgcnt_t		pgcnt;
1993 	caddr_t		a;
1994 	pgcnt_t		pidx;
1995 	size_t		sz;
1996 
1997 #ifdef lint
1998 	hat = hat;
1999 #endif
2000 
2001 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2002 
2003 	if (sptd->spt_flags & SHM_PAGEABLE) {
2004 		return (segspt_dismfault(hat, seg, addr, len, type, rw));
2005 	}
2006 
2007 	/*
2008 	 * Because of the way spt is implemented
2009 	 * the realsize of the segment does not have to be
2010 	 * equal to the segment size itself. The segment size is
2011 	 * often in multiples of a page size larger than PAGESIZE.
2012 	 * The realsize is rounded up to the nearest PAGESIZE
2013 	 * based on what the user requested. This is a bit of
2014 	 * ungliness that is historical but not easily fixed
2015 	 * without re-designing the higher levels of ISM.
2016 	 */
2017 	ASSERT(addr >= seg->s_base);
2018 	if (((addr + len) - seg->s_base) > sptd->spt_realsize)
2019 		return (FC_NOMAP);
2020 	/*
2021 	 * For all of the following cases except F_PROT, we need to
2022 	 * make any necessary adjustments to addr and len
2023 	 * and get all of the necessary page_t's into an array called ppa[].
2024 	 *
2025 	 * The code in shmat() forces base addr and len of ISM segment
2026 	 * to be aligned to largest page size supported. Therefore,
2027 	 * we are able to handle F_SOFTLOCK and F_INVAL calls in "large
2028 	 * pagesize" chunks. We want to make sure that we HAT_LOAD_LOCK
2029 	 * in large pagesize chunks, or else we will screw up the HAT
2030 	 * layer by calling hat_memload_array() with differing page sizes
2031 	 * over a given virtual range.
2032 	 */
2033 	pgsz = page_get_pagesize(sptseg->s_szc);
2034 	pgcnt = page_get_pagecnt(sptseg->s_szc);
2035 	shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), pgsz);
2036 	size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)), pgsz);
2037 	npages = btopr(size);
2038 
2039 	/*
2040 	 * Now we need to convert from addr in segshm to addr in segspt.
2041 	 */
2042 	anon_index = seg_page(seg, shm_addr);
2043 	sptseg_addr = sptseg->s_base + ptob(anon_index);
2044 
2045 	/*
2046 	 * And now we may have to adjust npages downward if we have
2047 	 * exceeded the realsize of the segment or initial anon
2048 	 * allocations.
2049 	 */
2050 	if ((sptseg_addr + ptob(npages)) >
2051 	    (sptseg->s_base + sptd->spt_realsize))
2052 		size = (sptseg->s_base + sptd->spt_realsize) - sptseg_addr;
2053 
2054 	npages = btopr(size);
2055 
2056 	ASSERT(sptseg_addr < (sptseg->s_base + sptseg->s_size));
2057 	ASSERT((sptd->spt_flags & SHM_PAGEABLE) == 0);
2058 
2059 	switch (type) {
2060 
2061 	case F_SOFTLOCK:
2062 
2063 		/*
2064 		 * availrmem is decremented once during anon_swap_adjust()
2065 		 * and is incremented during the anon_unresv(), which is
2066 		 * called from shm_rm_amp() when the segment is destroyed.
2067 		 */
2068 		atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), npages);
2069 		/*
2070 		 * Some platforms assume that ISM pages are SE_SHARED
2071 		 * locked for the entire life of the segment.
2072 		 */
2073 		if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0))
2074 			return (0);
2075 		/*
2076 		 * Fall through to the F_INVAL case to load up the hat layer
2077 		 * entries with the HAT_LOAD_LOCK flag.
2078 		 */
2079 
2080 		/* FALLTHRU */
2081 	case F_INVAL:
2082 
2083 		if ((rw == S_EXEC) && !(sptd->spt_prot & PROT_EXEC))
2084 			return (FC_NOMAP);
2085 
2086 		/*
2087 		 * Some platforms that do NOT support DYNAMIC_ISM_UNMAP
2088 		 * may still rely on this call to hat_share(). That
2089 		 * would imply that those hat's can fault on a
2090 		 * HAT_LOAD_LOCK translation, which would seem
2091 		 * contradictory.
2092 		 */
2093 		if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
2094 			if (hat_share(seg->s_as->a_hat, seg->s_base,
2095 			    curspt->a_hat, sptseg->s_base,
2096 			    sptseg->s_size, sptseg->s_szc) != 0) {
2097 				panic("hat_share error in ISM fault");
2098 				/*NOTREACHED*/
2099 			}
2100 			return (0);
2101 		}
2102 		ppa = kmem_zalloc(sizeof (page_t *) * npages, KM_SLEEP);
2103 
2104 		/*
2105 		 * I see no need to lock the real seg,
2106 		 * here, because all of our work will be on the underlying
2107 		 * dummy seg.
2108 		 *
2109 		 * sptseg_addr and npages now account for large pages.
2110 		 */
2111 		amp = sptd->spt_amp;
2112 		ASSERT(amp != NULL);
2113 		anon_index = seg_page(sptseg, sptseg_addr);
2114 
2115 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2116 		for (i = 0; i < npages; i++) {
2117 			ap = anon_get_ptr(amp->ahp, anon_index++);
2118 			ASSERT(ap != NULL);
2119 			swap_xlate(ap, &vp, &offset);
2120 			pp = page_lookup(vp, offset, SE_SHARED);
2121 			ASSERT(pp != NULL);
2122 			ppa[i] = pp;
2123 		}
2124 		ANON_LOCK_EXIT(&amp->a_rwlock);
2125 		ASSERT(i == npages);
2126 
2127 		/*
2128 		 * We are already holding the as->a_lock on the user's
2129 		 * real segment, but we need to hold the a_lock on the
2130 		 * underlying dummy as. This is mostly to satisfy the
2131 		 * underlying HAT layer.
2132 		 */
2133 		AS_LOCK_ENTER(sptseg->s_as, &sptseg->s_as->a_lock, RW_READER);
2134 		a = sptseg_addr;
2135 		pidx = 0;
2136 		if (type == F_SOFTLOCK) {
2137 			/*
2138 			 * Load up the translation keeping it
2139 			 * locked and don't unlock the page.
2140 			 */
2141 			for (; pidx < npages; a += pgsz, pidx += pgcnt) {
2142 				sz = MIN(pgsz, ptob(npages - pidx));
2143 				hat_memload_array(sptseg->s_as->a_hat, a,
2144 				    sz, &ppa[pidx], sptd->spt_prot,
2145 				    HAT_LOAD_LOCK | HAT_LOAD_SHARE);
2146 			}
2147 		} else {
2148 			if (hat == seg->s_as->a_hat) {
2149 
2150 				/*
2151 				 * Migrate pages marked for migration.
2152 				 */
2153 				if (lgrp_optimizations())
2154 					page_migrate(seg, shm_addr, ppa,
2155 					    npages);
2156 
2157 				/* CPU HAT */
2158 				for (; pidx < npages;
2159 				    a += pgsz, pidx += pgcnt) {
2160 					sz = MIN(pgsz, ptob(npages - pidx));
2161 					hat_memload_array(sptseg->s_as->a_hat,
2162 					    a, sz, &ppa[pidx],
2163 					    sptd->spt_prot, HAT_LOAD_SHARE);
2164 				}
2165 			} else {
2166 				/* XHAT. Pass real address */
2167 				hat_memload_array(hat, shm_addr,
2168 				    ptob(npages), ppa, sptd->spt_prot,
2169 				    HAT_LOAD_SHARE);
2170 			}
2171 
2172 			/*
2173 			 * And now drop the SE_SHARED lock(s).
2174 			 */
2175 			for (i = 0; i < npages; i++)
2176 				page_unlock(ppa[i]);
2177 		}
2178 		AS_LOCK_EXIT(sptseg->s_as, &sptseg->s_as->a_lock);
2179 
2180 		kmem_free(ppa, sizeof (page_t *) * npages);
2181 		return (0);
2182 	case F_SOFTUNLOCK:
2183 
2184 		/*
2185 		 * This is a bit ugly, we pass in the real seg pointer,
2186 		 * but the sptseg_addr is the virtual address within the
2187 		 * dummy seg.
2188 		 */
2189 		segspt_softunlock(seg, sptseg_addr, ptob(npages), rw);
2190 		return (0);
2191 
2192 	case F_PROT:
2193 
2194 		/*
2195 		 * This takes care of the unusual case where a user
2196 		 * allocates a stack in shared memory and a register
2197 		 * window overflow is written to that stack page before
2198 		 * it is otherwise modified.
2199 		 *
2200 		 * We can get away with this because ISM segments are
2201 		 * always rw. Other than this unusual case, there
2202 		 * should be no instances of protection violations.
2203 		 */
2204 		return (0);
2205 
2206 	default:
2207 #ifdef DEBUG
2208 		cmn_err(CE_WARN, "segspt_shmfault default type?");
2209 #endif
2210 		return (FC_NOMAP);
2211 	}
2212 }
2213 
2214 /*ARGSUSED*/
2215 static faultcode_t
2216 segspt_shmfaulta(struct seg *seg, caddr_t addr)
2217 {
2218 	return (0);
2219 }
2220 
2221 /*ARGSUSED*/
2222 static int
2223 segspt_shmkluster(struct seg *seg, caddr_t addr, ssize_t delta)
2224 {
2225 	return (0);
2226 }
2227 
2228 /*ARGSUSED*/
2229 static size_t
2230 segspt_shmswapout(struct seg *seg)
2231 {
2232 	return (0);
2233 }
2234 
2235 /*
2236  * duplicate the shared page tables
2237  */
2238 int
2239 segspt_shmdup(struct seg *seg, struct seg *newseg)
2240 {
2241 	struct shm_data		*shmd = (struct shm_data *)seg->s_data;
2242 	struct anon_map 	*amp = shmd->shm_amp;
2243 	struct shm_data 	*shmd_new;
2244 	struct seg		*spt_seg = shmd->shm_sptseg;
2245 	struct spt_data		*sptd = spt_seg->s_data;
2246 	int			error = 0;
2247 
2248 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
2249 
2250 	shmd_new = kmem_zalloc((sizeof (*shmd_new)), KM_SLEEP);
2251 	newseg->s_data = (void *)shmd_new;
2252 	shmd_new->shm_sptas = shmd->shm_sptas;
2253 	shmd_new->shm_amp = amp;
2254 	shmd_new->shm_sptseg = shmd->shm_sptseg;
2255 	newseg->s_ops = &segspt_shmops;
2256 	newseg->s_szc = seg->s_szc;
2257 	ASSERT(seg->s_szc == shmd->shm_sptseg->s_szc);
2258 
2259 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
2260 	amp->refcnt++;
2261 	ANON_LOCK_EXIT(&amp->a_rwlock);
2262 
2263 	if (sptd->spt_flags & SHM_PAGEABLE) {
2264 		shmd_new->shm_vpage = kmem_zalloc(btopr(amp->size), KM_SLEEP);
2265 		shmd_new->shm_lckpgs = 0;
2266 		if (hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
2267 			if ((error = hat_share(newseg->s_as->a_hat,
2268 			    newseg->s_base, shmd->shm_sptas->a_hat, SEGSPTADDR,
2269 			    seg->s_size, seg->s_szc)) != 0) {
2270 				kmem_free(shmd_new->shm_vpage,
2271 				    btopr(amp->size));
2272 			}
2273 		}
2274 		return (error);
2275 	} else {
2276 		return (hat_share(newseg->s_as->a_hat, newseg->s_base,
2277 		    shmd->shm_sptas->a_hat, SEGSPTADDR, seg->s_size,
2278 		    seg->s_szc));
2279 
2280 	}
2281 }
2282 
2283 /*ARGSUSED*/
2284 int
2285 segspt_shmcheckprot(struct seg *seg, caddr_t addr, size_t size, uint_t prot)
2286 {
2287 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2288 	struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2289 
2290 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2291 
2292 	/*
2293 	 * ISM segment is always rw.
2294 	 */
2295 	return (((sptd->spt_prot & prot) != prot) ? EACCES : 0);
2296 }
2297 
2298 /*
2299  * Return an array of locked large pages, for empty slots allocate
2300  * private zero-filled anon pages.
2301  */
2302 static int
2303 spt_anon_getpages(
2304 	struct seg *sptseg,
2305 	caddr_t sptaddr,
2306 	size_t len,
2307 	page_t *ppa[])
2308 {
2309 	struct  spt_data *sptd = sptseg->s_data;
2310 	struct  anon_map *amp = sptd->spt_amp;
2311 	enum 	seg_rw rw = sptd->spt_prot;
2312 	uint_t	szc = sptseg->s_szc;
2313 	size_t	pg_sz, share_sz = page_get_pagesize(szc);
2314 	pgcnt_t	lp_npgs;
2315 	caddr_t	lp_addr, e_sptaddr;
2316 	uint_t	vpprot, ppa_szc = 0;
2317 	struct  vpage *vpage = NULL;
2318 	ulong_t	j, ppa_idx;
2319 	int	err, ierr = 0;
2320 	pgcnt_t	an_idx;
2321 	anon_sync_obj_t cookie;
2322 	int anon_locked = 0;
2323 	pgcnt_t amp_pgs;
2324 
2325 
2326 	ASSERT(IS_P2ALIGNED(sptaddr, share_sz) && IS_P2ALIGNED(len, share_sz));
2327 	ASSERT(len != 0);
2328 
2329 	pg_sz = share_sz;
2330 	lp_npgs = btop(pg_sz);
2331 	lp_addr = sptaddr;
2332 	e_sptaddr = sptaddr + len;
2333 	an_idx = seg_page(sptseg, sptaddr);
2334 	ppa_idx = 0;
2335 
2336 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2337 
2338 	amp_pgs = page_get_pagecnt(amp->a_szc);
2339 
2340 	/*CONSTCOND*/
2341 	while (1) {
2342 		for (; lp_addr < e_sptaddr;
2343 		    an_idx += lp_npgs, lp_addr += pg_sz, ppa_idx += lp_npgs) {
2344 
2345 			/*
2346 			 * If we're currently locked, and we get to a new
2347 			 * page, unlock our current anon chunk.
2348 			 */
2349 			if (anon_locked && P2PHASE(an_idx, amp_pgs) == 0) {
2350 				anon_array_exit(&cookie);
2351 				anon_locked = 0;
2352 			}
2353 			if (!anon_locked) {
2354 				anon_array_enter(amp, an_idx, &cookie);
2355 				anon_locked = 1;
2356 			}
2357 			ppa_szc = (uint_t)-1;
2358 			ierr = anon_map_getpages(amp, an_idx, szc, sptseg,
2359 			    lp_addr, sptd->spt_prot, &vpprot, &ppa[ppa_idx],
2360 			    &ppa_szc, vpage, rw, 0, segvn_anypgsz, 0, kcred);
2361 
2362 			if (ierr != 0) {
2363 				if (ierr > 0) {
2364 					err = FC_MAKE_ERR(ierr);
2365 					goto lpgs_err;
2366 				}
2367 				break;
2368 			}
2369 		}
2370 		if (lp_addr == e_sptaddr) {
2371 			break;
2372 		}
2373 		ASSERT(lp_addr < e_sptaddr);
2374 
2375 		/*
2376 		 * ierr == -1 means we failed to allocate a large page.
2377 		 * so do a size down operation.
2378 		 *
2379 		 * ierr == -2 means some other process that privately shares
2380 		 * pages with this process has allocated a larger page and we
2381 		 * need to retry with larger pages. So do a size up
2382 		 * operation. This relies on the fact that large pages are
2383 		 * never partially shared i.e. if we share any constituent
2384 		 * page of a large page with another process we must share the
2385 		 * entire large page. Note this cannot happen for SOFTLOCK
2386 		 * case, unless current address (lpaddr) is at the beginning
2387 		 * of the next page size boundary because the other process
2388 		 * couldn't have relocated locked pages.
2389 		 */
2390 		ASSERT(ierr == -1 || ierr == -2);
2391 		if (segvn_anypgsz) {
2392 			ASSERT(ierr == -2 || szc != 0);
2393 			ASSERT(ierr == -1 || szc < sptseg->s_szc);
2394 			szc = (ierr == -1) ? szc - 1 : szc + 1;
2395 		} else {
2396 			/*
2397 			 * For faults and segvn_anypgsz == 0
2398 			 * we need to be careful not to loop forever
2399 			 * if existing page is found with szc other
2400 			 * than 0 or seg->s_szc. This could be due
2401 			 * to page relocations on behalf of DR or
2402 			 * more likely large page creation. For this
2403 			 * case simply re-size to existing page's szc
2404 			 * if returned by anon_map_getpages().
2405 			 */
2406 			if (ppa_szc == (uint_t)-1) {
2407 				szc = (ierr == -1) ? 0 : sptseg->s_szc;
2408 			} else {
2409 				ASSERT(ppa_szc <= sptseg->s_szc);
2410 				ASSERT(ierr == -2 || ppa_szc < szc);
2411 				ASSERT(ierr == -1 || ppa_szc > szc);
2412 				szc = ppa_szc;
2413 			}
2414 		}
2415 		pg_sz = page_get_pagesize(szc);
2416 		lp_npgs = btop(pg_sz);
2417 		ASSERT(IS_P2ALIGNED(lp_addr, pg_sz));
2418 	}
2419 	if (anon_locked) {
2420 		anon_array_exit(&cookie);
2421 	}
2422 	ANON_LOCK_EXIT(&amp->a_rwlock);
2423 	return (0);
2424 
2425 lpgs_err:
2426 	if (anon_locked) {
2427 		anon_array_exit(&cookie);
2428 	}
2429 	ANON_LOCK_EXIT(&amp->a_rwlock);
2430 	for (j = 0; j < ppa_idx; j++)
2431 		page_unlock(ppa[j]);
2432 	return (err);
2433 }
2434 
2435 /*
2436  * count the number of bytes in a set of spt pages that are currently not
2437  * locked
2438  */
2439 static rctl_qty_t
2440 spt_unlockedbytes(pgcnt_t npages, page_t **ppa)
2441 {
2442 	ulong_t	i;
2443 	rctl_qty_t unlocked = 0;
2444 
2445 	for (i = 0; i < npages; i++) {
2446 		if (ppa[i]->p_lckcnt == 0)
2447 			unlocked += PAGESIZE;
2448 	}
2449 	return (unlocked);
2450 }
2451 
2452 int
2453 spt_lockpages(struct seg *seg, pgcnt_t anon_index, pgcnt_t npages,
2454     page_t **ppa, ulong_t *lockmap, size_t pos,
2455     rctl_qty_t *locked)
2456 {
2457 	struct shm_data *shmd = seg->s_data;
2458 	struct spt_data *sptd = shmd->shm_sptseg->s_data;
2459 	ulong_t	i;
2460 	int	kernel;
2461 
2462 	/* return the number of bytes actually locked */
2463 	*locked = 0;
2464 	for (i = 0; i < npages; anon_index++, pos++, i++) {
2465 		if (!(shmd->shm_vpage[anon_index] & DISM_PG_LOCKED)) {
2466 			if (sptd->spt_ppa_lckcnt[anon_index] <
2467 			    (ushort_t)DISM_LOCK_MAX) {
2468 				if (++sptd->spt_ppa_lckcnt[anon_index] ==
2469 				    (ushort_t)DISM_LOCK_MAX) {
2470 					cmn_err(CE_WARN,
2471 					    "DISM page lock limit "
2472 					    "reached on DISM offset 0x%lx\n",
2473 					    anon_index << PAGESHIFT);
2474 				}
2475 				kernel = (sptd->spt_ppa &&
2476 				    sptd->spt_ppa[anon_index]) ? 1 : 0;
2477 				if (!page_pp_lock(ppa[i], 0, kernel)) {
2478 					sptd->spt_ppa_lckcnt[anon_index]--;
2479 					return (EAGAIN);
2480 				}
2481 				/* if this is a newly locked page, count it */
2482 				if (ppa[i]->p_lckcnt == 1) {
2483 					*locked += PAGESIZE;
2484 				}
2485 				shmd->shm_lckpgs++;
2486 				shmd->shm_vpage[anon_index] |= DISM_PG_LOCKED;
2487 				if (lockmap != NULL)
2488 					BT_SET(lockmap, pos);
2489 			}
2490 		}
2491 	}
2492 	return (0);
2493 }
2494 
2495 /*ARGSUSED*/
2496 static int
2497 segspt_shmlockop(struct seg *seg, caddr_t addr, size_t len,
2498     int attr, int op, ulong_t *lockmap, size_t pos)
2499 {
2500 	struct shm_data *shmd = seg->s_data;
2501 	struct seg	*sptseg = shmd->shm_sptseg;
2502 	struct spt_data *sptd = sptseg->s_data;
2503 	struct kshmid	*sp = sptd->spt_amp->a_sp;
2504 	pgcnt_t		npages, a_npages;
2505 	page_t		**ppa;
2506 	pgcnt_t 	an_idx, a_an_idx, ppa_idx;
2507 	caddr_t		spt_addr, a_addr;	/* spt and aligned address */
2508 	size_t		a_len;			/* aligned len */
2509 	size_t		share_sz;
2510 	ulong_t		i;
2511 	int		sts = 0;
2512 	rctl_qty_t	unlocked = 0;
2513 	rctl_qty_t	locked = 0;
2514 	struct proc	*p = curproc;
2515 	kproject_t	*proj;
2516 
2517 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2518 	ASSERT(sp != NULL);
2519 
2520 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
2521 		return (0);
2522 	}
2523 
2524 	addr = (caddr_t)((uintptr_t)addr & (uintptr_t)PAGEMASK);
2525 	an_idx = seg_page(seg, addr);
2526 	npages = btopr(len);
2527 
2528 	if (an_idx + npages > btopr(shmd->shm_amp->size)) {
2529 		return (ENOMEM);
2530 	}
2531 
2532 	/*
2533 	 * A shm's project never changes, so no lock needed.
2534 	 * The shm has a hold on the project, so it will not go away.
2535 	 * Since we have a mapping to shm within this zone, we know
2536 	 * that the zone will not go away.
2537 	 */
2538 	proj = sp->shm_perm.ipc_proj;
2539 
2540 	if (op == MC_LOCK) {
2541 
2542 		/*
2543 		 * Need to align addr and size request if they are not
2544 		 * aligned so we can always allocate large page(s) however
2545 		 * we only lock what was requested in initial request.
2546 		 */
2547 		share_sz = page_get_pagesize(sptseg->s_szc);
2548 		a_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), share_sz);
2549 		a_len = P2ROUNDUP((uintptr_t)(((addr + len) - a_addr)),
2550 		    share_sz);
2551 		a_npages = btop(a_len);
2552 		a_an_idx = seg_page(seg, a_addr);
2553 		spt_addr = sptseg->s_base + ptob(a_an_idx);
2554 		ppa_idx = an_idx - a_an_idx;
2555 
2556 		if ((ppa = kmem_zalloc(((sizeof (page_t *)) * a_npages),
2557 		    KM_NOSLEEP)) == NULL) {
2558 			return (ENOMEM);
2559 		}
2560 
2561 		/*
2562 		 * Don't cache any new pages for IO and
2563 		 * flush any cached pages.
2564 		 */
2565 		mutex_enter(&sptd->spt_lock);
2566 		if (sptd->spt_ppa != NULL)
2567 			sptd->spt_flags |= DISM_PPA_CHANGED;
2568 
2569 		sts = spt_anon_getpages(sptseg, spt_addr, a_len, ppa);
2570 		if (sts != 0) {
2571 			mutex_exit(&sptd->spt_lock);
2572 			kmem_free(ppa, ((sizeof (page_t *)) * a_npages));
2573 			return (sts);
2574 		}
2575 
2576 		mutex_enter(&sp->shm_mlock);
2577 		/* enforce locked memory rctl */
2578 		unlocked = spt_unlockedbytes(npages, &ppa[ppa_idx]);
2579 
2580 		mutex_enter(&p->p_lock);
2581 		if (rctl_incr_locked_mem(p, proj, unlocked, 0)) {
2582 			mutex_exit(&p->p_lock);
2583 			sts = EAGAIN;
2584 		} else {
2585 			mutex_exit(&p->p_lock);
2586 			sts = spt_lockpages(seg, an_idx, npages,
2587 			    &ppa[ppa_idx], lockmap, pos, &locked);
2588 
2589 			/*
2590 			 * correct locked count if not all pages could be
2591 			 * locked
2592 			 */
2593 			if ((unlocked - locked) > 0) {
2594 				rctl_decr_locked_mem(NULL, proj,
2595 				    (unlocked - locked), 0);
2596 			}
2597 		}
2598 		/*
2599 		 * unlock pages
2600 		 */
2601 		for (i = 0; i < a_npages; i++)
2602 			page_unlock(ppa[i]);
2603 		if (sptd->spt_ppa != NULL)
2604 			sptd->spt_flags |= DISM_PPA_CHANGED;
2605 		mutex_exit(&sp->shm_mlock);
2606 		mutex_exit(&sptd->spt_lock);
2607 
2608 		kmem_free(ppa, ((sizeof (page_t *)) * a_npages));
2609 
2610 	} else if (op == MC_UNLOCK) { /* unlock */
2611 		struct anon_map *amp;
2612 		struct anon 	*ap;
2613 		struct vnode 	*vp;
2614 		u_offset_t 	off;
2615 		struct page	*pp;
2616 		int		kernel;
2617 		anon_sync_obj_t cookie;
2618 		rctl_qty_t	unlocked = 0;
2619 
2620 		amp = sptd->spt_amp;
2621 		mutex_enter(&sptd->spt_lock);
2622 		if (shmd->shm_lckpgs == 0) {
2623 			mutex_exit(&sptd->spt_lock);
2624 			return (0);
2625 		}
2626 		/*
2627 		 * Don't cache new IO pages.
2628 		 */
2629 		if (sptd->spt_ppa != NULL)
2630 			sptd->spt_flags |= DISM_PPA_CHANGED;
2631 
2632 		mutex_enter(&sp->shm_mlock);
2633 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2634 		for (i = 0; i < npages; i++, an_idx++) {
2635 			if (shmd->shm_vpage[an_idx] & DISM_PG_LOCKED) {
2636 				anon_array_enter(amp, an_idx, &cookie);
2637 				ap = anon_get_ptr(amp->ahp, an_idx);
2638 				ASSERT(ap);
2639 
2640 				swap_xlate(ap, &vp, &off);
2641 				anon_array_exit(&cookie);
2642 				pp = page_lookup(vp, off, SE_SHARED);
2643 				ASSERT(pp);
2644 				/*
2645 				 * the availrmem is decremented only for
2646 				 * pages which are not in seg pcache,
2647 				 * for pages in seg pcache availrmem was
2648 				 * decremented in _dismpagelock() (if
2649 				 * they were not locked here)
2650 				 */
2651 				kernel = (sptd->spt_ppa &&
2652 				    sptd->spt_ppa[an_idx]) ? 1 : 0;
2653 				ASSERT(pp->p_lckcnt > 0);
2654 				page_pp_unlock(pp, 0, kernel);
2655 				if (pp->p_lckcnt == 0)
2656 					unlocked += PAGESIZE;
2657 				page_unlock(pp);
2658 				shmd->shm_vpage[an_idx] &= ~DISM_PG_LOCKED;
2659 				sptd->spt_ppa_lckcnt[an_idx]--;
2660 				shmd->shm_lckpgs--;
2661 			}
2662 		}
2663 		ANON_LOCK_EXIT(&amp->a_rwlock);
2664 		if (sptd->spt_ppa != NULL)
2665 			sptd->spt_flags |= DISM_PPA_CHANGED;
2666 		mutex_exit(&sptd->spt_lock);
2667 
2668 		rctl_decr_locked_mem(NULL, proj, unlocked, 0);
2669 		mutex_exit(&sp->shm_mlock);
2670 	}
2671 	return (sts);
2672 }
2673 
2674 /*ARGSUSED*/
2675 int
2676 segspt_shmgetprot(struct seg *seg, caddr_t addr, size_t len, uint_t *protv)
2677 {
2678 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2679 	struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2680 	spgcnt_t pgno = seg_page(seg, addr+len) - seg_page(seg, addr) + 1;
2681 
2682 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2683 
2684 	/*
2685 	 * ISM segment is always rw.
2686 	 */
2687 	while (--pgno >= 0)
2688 		*protv++ = sptd->spt_prot;
2689 	return (0);
2690 }
2691 
2692 /*ARGSUSED*/
2693 u_offset_t
2694 segspt_shmgetoffset(struct seg *seg, caddr_t addr)
2695 {
2696 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2697 
2698 	/* Offset does not matter in ISM memory */
2699 
2700 	return ((u_offset_t)0);
2701 }
2702 
2703 /* ARGSUSED */
2704 int
2705 segspt_shmgettype(struct seg *seg, caddr_t addr)
2706 {
2707 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2708 	struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2709 
2710 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2711 
2712 	/*
2713 	 * The shared memory mapping is always MAP_SHARED, SWAP is only
2714 	 * reserved for DISM
2715 	 */
2716 	return (MAP_SHARED |
2717 	    ((sptd->spt_flags & SHM_PAGEABLE) ? 0 : MAP_NORESERVE));
2718 }
2719 
2720 /*ARGSUSED*/
2721 int
2722 segspt_shmgetvp(struct seg *seg, caddr_t addr, struct vnode **vpp)
2723 {
2724 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2725 	struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2726 
2727 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2728 
2729 	*vpp = sptd->spt_vp;
2730 	return (0);
2731 }
2732 
2733 /*
2734  * We need to wait for pending IO to complete to a DISM segment in order for
2735  * pages to get kicked out of the seg_pcache.  120 seconds should be more
2736  * than enough time to wait.
2737  */
2738 static clock_t spt_pcache_wait = 120;
2739 
2740 /*ARGSUSED*/
2741 static int
2742 segspt_shmadvise(struct seg *seg, caddr_t addr, size_t len, uint_t behav)
2743 {
2744 	struct shm_data	*shmd = (struct shm_data *)seg->s_data;
2745 	struct spt_data	*sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2746 	struct anon_map	*amp;
2747 	pgcnt_t pg_idx;
2748 	ushort_t gen;
2749 	clock_t	end_lbolt;
2750 	int writer;
2751 
2752 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2753 
2754 	if (behav == MADV_FREE) {
2755 		if ((sptd->spt_flags & SHM_PAGEABLE) == 0)
2756 			return (0);
2757 
2758 		amp = sptd->spt_amp;
2759 		pg_idx = seg_page(seg, addr);
2760 
2761 		mutex_enter(&sptd->spt_lock);
2762 		if (sptd->spt_ppa == NULL) {
2763 			mutex_exit(&sptd->spt_lock);
2764 			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2765 			anon_disclaim(amp, pg_idx, len);
2766 			ANON_LOCK_EXIT(&amp->a_rwlock);
2767 			return (0);
2768 		}
2769 
2770 		sptd->spt_flags |= DISM_PPA_CHANGED;
2771 		gen = sptd->spt_gen;
2772 
2773 		mutex_exit(&sptd->spt_lock);
2774 
2775 		/*
2776 		 * Purge all DISM cached pages
2777 		 */
2778 		seg_ppurge_seg(segspt_reclaim);
2779 
2780 		/*
2781 		 * Drop the AS_LOCK so that other threads can grab it
2782 		 * in the as_pageunlock path and hopefully get the segment
2783 		 * kicked out of the seg_pcache.  We bump the shm_softlockcnt
2784 		 * to keep this segment resident.
2785 		 */
2786 		writer = AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock);
2787 		atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), 1);
2788 		AS_LOCK_EXIT(seg->s_as, &seg->s_as->a_lock);
2789 
2790 		mutex_enter(&sptd->spt_lock);
2791 
2792 		end_lbolt = lbolt + (hz * spt_pcache_wait);
2793 
2794 		/*
2795 		 * Try to wait for pages to get kicked out of the seg_pcache.
2796 		 */
2797 		while (sptd->spt_gen == gen &&
2798 		    (sptd->spt_flags & DISM_PPA_CHANGED) &&
2799 		    lbolt < end_lbolt) {
2800 			if (!cv_timedwait_sig(&sptd->spt_cv,
2801 			    &sptd->spt_lock, end_lbolt)) {
2802 				break;
2803 			}
2804 		}
2805 
2806 		mutex_exit(&sptd->spt_lock);
2807 
2808 		/* Regrab the AS_LOCK and release our hold on the segment */
2809 		AS_LOCK_ENTER(seg->s_as, &seg->s_as->a_lock,
2810 		    writer ? RW_WRITER : RW_READER);
2811 		atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), -1);
2812 		if (shmd->shm_softlockcnt <= 0) {
2813 			if (AS_ISUNMAPWAIT(seg->s_as)) {
2814 				mutex_enter(&seg->s_as->a_contents);
2815 				if (AS_ISUNMAPWAIT(seg->s_as)) {
2816 					AS_CLRUNMAPWAIT(seg->s_as);
2817 					cv_broadcast(&seg->s_as->a_cv);
2818 				}
2819 				mutex_exit(&seg->s_as->a_contents);
2820 			}
2821 		}
2822 
2823 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2824 		anon_disclaim(amp, pg_idx, len);
2825 		ANON_LOCK_EXIT(&amp->a_rwlock);
2826 	} else if (lgrp_optimizations() && (behav == MADV_ACCESS_LWP ||
2827 	    behav == MADV_ACCESS_MANY || behav == MADV_ACCESS_DEFAULT)) {
2828 		int			already_set;
2829 		ulong_t			anon_index;
2830 		lgrp_mem_policy_t	policy;
2831 		caddr_t			shm_addr;
2832 		size_t			share_size;
2833 		size_t			size;
2834 		struct seg		*sptseg = shmd->shm_sptseg;
2835 		caddr_t			sptseg_addr;
2836 
2837 		/*
2838 		 * Align address and length to page size of underlying segment
2839 		 */
2840 		share_size = page_get_pagesize(shmd->shm_sptseg->s_szc);
2841 		shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), share_size);
2842 		size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)),
2843 		    share_size);
2844 
2845 		amp = shmd->shm_amp;
2846 		anon_index = seg_page(seg, shm_addr);
2847 
2848 		/*
2849 		 * And now we may have to adjust size downward if we have
2850 		 * exceeded the realsize of the segment or initial anon
2851 		 * allocations.
2852 		 */
2853 		sptseg_addr = sptseg->s_base + ptob(anon_index);
2854 		if ((sptseg_addr + size) >
2855 		    (sptseg->s_base + sptd->spt_realsize))
2856 			size = (sptseg->s_base + sptd->spt_realsize) -
2857 			    sptseg_addr;
2858 
2859 		/*
2860 		 * Set memory allocation policy for this segment
2861 		 */
2862 		policy = lgrp_madv_to_policy(behav, len, MAP_SHARED);
2863 		already_set = lgrp_shm_policy_set(policy, amp, anon_index,
2864 		    NULL, 0, len);
2865 
2866 		/*
2867 		 * If random memory allocation policy set already,
2868 		 * don't bother reapplying it.
2869 		 */
2870 		if (already_set && !LGRP_MEM_POLICY_REAPPLICABLE(policy))
2871 			return (0);
2872 
2873 		/*
2874 		 * Mark any existing pages in the given range for
2875 		 * migration, flushing the I/O page cache, and using
2876 		 * underlying segment to calculate anon index and get
2877 		 * anonmap and vnode pointer from
2878 		 */
2879 		if (shmd->shm_softlockcnt > 0)
2880 			segspt_purge(seg);
2881 
2882 		page_mark_migrate(seg, shm_addr, size, amp, 0, NULL, 0, 0);
2883 	}
2884 
2885 	return (0);
2886 }
2887 
2888 /*ARGSUSED*/
2889 void
2890 segspt_shmdump(struct seg *seg)
2891 {
2892 	/* no-op for ISM segment */
2893 }
2894 
2895 /*ARGSUSED*/
2896 static faultcode_t
2897 segspt_shmsetpgsz(struct seg *seg, caddr_t addr, size_t len, uint_t szc)
2898 {
2899 	return (ENOTSUP);
2900 }
2901 
2902 /*
2903  * get a memory ID for an addr in a given segment
2904  */
2905 static int
2906 segspt_shmgetmemid(struct seg *seg, caddr_t addr, memid_t *memidp)
2907 {
2908 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2909 	struct anon 	*ap;
2910 	size_t		anon_index;
2911 	struct anon_map	*amp = shmd->shm_amp;
2912 	struct spt_data	*sptd = shmd->shm_sptseg->s_data;
2913 	struct seg	*sptseg = shmd->shm_sptseg;
2914 	anon_sync_obj_t	cookie;
2915 
2916 	anon_index = seg_page(seg, addr);
2917 
2918 	if (addr > (seg->s_base + sptd->spt_realsize)) {
2919 		return (EFAULT);
2920 	}
2921 
2922 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2923 	anon_array_enter(amp, anon_index, &cookie);
2924 	ap = anon_get_ptr(amp->ahp, anon_index);
2925 	if (ap == NULL) {
2926 		struct page *pp;
2927 		caddr_t spt_addr = sptseg->s_base + ptob(anon_index);
2928 
2929 		pp = anon_zero(sptseg, spt_addr, &ap, kcred);
2930 		if (pp == NULL) {
2931 			anon_array_exit(&cookie);
2932 			ANON_LOCK_EXIT(&amp->a_rwlock);
2933 			return (ENOMEM);
2934 		}
2935 		(void) anon_set_ptr(amp->ahp, anon_index, ap, ANON_SLEEP);
2936 		page_unlock(pp);
2937 	}
2938 	anon_array_exit(&cookie);
2939 	ANON_LOCK_EXIT(&amp->a_rwlock);
2940 	memidp->val[0] = (uintptr_t)ap;
2941 	memidp->val[1] = (uintptr_t)addr & PAGEOFFSET;
2942 	return (0);
2943 }
2944 
2945 /*
2946  * Get memory allocation policy info for specified address in given segment
2947  */
2948 static lgrp_mem_policy_info_t *
2949 segspt_shmgetpolicy(struct seg *seg, caddr_t addr)
2950 {
2951 	struct anon_map		*amp;
2952 	ulong_t			anon_index;
2953 	lgrp_mem_policy_info_t	*policy_info;
2954 	struct shm_data		*shm_data;
2955 
2956 	ASSERT(seg != NULL);
2957 
2958 	/*
2959 	 * Get anon_map from segshm
2960 	 *
2961 	 * Assume that no lock needs to be held on anon_map, since
2962 	 * it should be protected by its reference count which must be
2963 	 * nonzero for an existing segment
2964 	 * Need to grab readers lock on policy tree though
2965 	 */
2966 	shm_data = (struct shm_data *)seg->s_data;
2967 	if (shm_data == NULL)
2968 		return (NULL);
2969 	amp = shm_data->shm_amp;
2970 	ASSERT(amp->refcnt != 0);
2971 
2972 	/*
2973 	 * Get policy info
2974 	 *
2975 	 * Assume starting anon index of 0
2976 	 */
2977 	anon_index = seg_page(seg, addr);
2978 	policy_info = lgrp_shm_policy_get(amp, anon_index, NULL, 0);
2979 
2980 	return (policy_info);
2981 }
2982 
2983 /*ARGSUSED*/
2984 static int
2985 segspt_shmcapable(struct seg *seg, segcapability_t capability)
2986 {
2987 	return (0);
2988 }
2989