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 (c) 1993, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright (c) 2015, Joyent, Inc. All rights reserved.
  24  * Copyright (c) 2016 by Delphix. All rights reserved.
  25  */
  26 
  27 #include <sys/param.h>
  28 #include <sys/user.h>
  29 #include <sys/mman.h>
  30 #include <sys/kmem.h>
  31 #include <sys/sysmacros.h>
  32 #include <sys/cmn_err.h>
  33 #include <sys/systm.h>
  34 #include <sys/tuneable.h>
  35 #include <vm/hat.h>
  36 #include <vm/seg.h>
  37 #include <vm/as.h>
  38 #include <vm/anon.h>
  39 #include <vm/page.h>
  40 #include <sys/buf.h>
  41 #include <sys/swap.h>
  42 #include <sys/atomic.h>
  43 #include <vm/seg_spt.h>
  44 #include <sys/debug.h>
  45 #include <sys/vtrace.h>
  46 #include <sys/shm.h>
  47 #include <sys/shm_impl.h>
  48 #include <sys/lgrp.h>
  49 #include <sys/vmsystm.h>
  50 #include <sys/policy.h>
  51 #include <sys/project.h>
  52 #include <sys/tnf_probe.h>
  53 #include <sys/zone.h>
  54 
  55 #define SEGSPTADDR      (caddr_t)0x0
  56 
  57 /*
  58  * # pages used for spt
  59  */
  60 size_t  spt_used;
  61 
  62 /*
  63  * segspt_minfree is the memory left for system after ISM
  64  * locked its pages; it is set up to 5% of availrmem in
  65  * sptcreate when ISM is created.  ISM should not use more
  66  * than ~90% of availrmem; if it does, then the performance
  67  * of the system may decrease. Machines with large memories may
  68  * be able to use up more memory for ISM so we set the default
  69  * segspt_minfree to 5% (which gives ISM max 95% of availrmem.
  70  * If somebody wants even more memory for ISM (risking hanging
  71  * the system) they can patch the segspt_minfree to smaller number.
  72  */
  73 pgcnt_t segspt_minfree = 0;
  74 
  75 static int segspt_create(struct seg *seg, caddr_t argsp);
  76 static int segspt_unmap(struct seg *seg, caddr_t raddr, size_t ssize);
  77 static void segspt_free(struct seg *seg);
  78 static void segspt_free_pages(struct seg *seg, caddr_t addr, size_t len);
  79 static lgrp_mem_policy_info_t *segspt_getpolicy(struct seg *seg, caddr_t addr);
  80 
  81 static void
  82 segspt_badop()
  83 {
  84         panic("segspt_badop called");
  85         /*NOTREACHED*/
  86 }
  87 
  88 #define SEGSPT_BADOP(t) (t(*)())segspt_badop
  89 
  90 struct seg_ops segspt_ops = {
  91         SEGSPT_BADOP(int),              /* dup */
  92         segspt_unmap,
  93         segspt_free,
  94         SEGSPT_BADOP(int),              /* fault */
  95         SEGSPT_BADOP(faultcode_t),      /* faulta */
  96         SEGSPT_BADOP(int),              /* setprot */
  97         SEGSPT_BADOP(int),              /* checkprot */
  98         SEGSPT_BADOP(int),              /* kluster */
  99         SEGSPT_BADOP(size_t),           /* swapout */
 100         SEGSPT_BADOP(int),              /* sync */
 101         SEGSPT_BADOP(size_t),           /* incore */
 102         SEGSPT_BADOP(int),              /* lockop */
 103         SEGSPT_BADOP(int),              /* getprot */
 104         SEGSPT_BADOP(u_offset_t),       /* getoffset */
 105         SEGSPT_BADOP(int),              /* gettype */
 106         SEGSPT_BADOP(int),              /* getvp */
 107         SEGSPT_BADOP(int),              /* advise */
 108         SEGSPT_BADOP(void),             /* dump */
 109         SEGSPT_BADOP(int),              /* pagelock */
 110         SEGSPT_BADOP(int),              /* setpgsz */
 111         SEGSPT_BADOP(int),              /* getmemid */
 112         segspt_getpolicy,               /* getpolicy */
 113         SEGSPT_BADOP(int),              /* capable */
 114         seg_inherit_notsup              /* inherit */
 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         seg_inherit_notsup
 175 };
 176 
 177 static void segspt_purge(struct seg *seg);
 178 static int segspt_reclaim(void *, caddr_t, size_t, struct page **,
 179                 enum seg_rw, int);
 180 static int spt_anon_getpages(struct seg *seg, caddr_t addr, size_t len,
 181                 page_t **ppa);
 182 
 183 
 184 
 185 /*ARGSUSED*/
 186 int
 187 sptcreate(size_t size, struct seg **sptseg, struct anon_map *amp,
 188     uint_t prot, uint_t flags, uint_t share_szc)
 189 {
 190         int     err;
 191         struct  as      *newas;
 192         struct  segspt_crargs sptcargs;
 193 
 194 #ifdef DEBUG
 195         TNF_PROBE_1(sptcreate, "spt", /* CSTYLED */,
 196                         tnf_ulong, size, size );
 197 #endif
 198         if (segspt_minfree == 0)        /* leave min 5% of availrmem for */
 199                 segspt_minfree = availrmem/20;  /* for the system */
 200 
 201         if (!hat_supported(HAT_SHARED_PT, (void *)0))
 202                 return (EINVAL);
 203 
 204         /*
 205          * get a new as for this shared memory segment
 206          */
 207         newas = as_alloc();
 208         newas->a_proc = NULL;
 209         sptcargs.amp = amp;
 210         sptcargs.prot = prot;
 211         sptcargs.flags = flags;
 212         sptcargs.szc = share_szc;
 213         /*
 214          * create a shared page table (spt) segment
 215          */
 216 
 217         if (err = as_map(newas, SEGSPTADDR, size, segspt_create, &sptcargs)) {
 218                 as_free(newas);
 219                 return (err);
 220         }
 221         *sptseg = sptcargs.seg_spt;
 222         return (0);
 223 }
 224 
 225 void
 226 sptdestroy(struct as *as, struct anon_map *amp)
 227 {
 228 
 229 #ifdef DEBUG
 230         TNF_PROBE_0(sptdestroy, "spt", /* CSTYLED */);
 231 #endif
 232         (void) as_unmap(as, SEGSPTADDR, amp->size);
 233         as_free(as);
 234 }
 235 
 236 /*
 237  * called from seg_free().
 238  * free (i.e., unlock, unmap, return to free list)
 239  *  all the pages in the given seg.
 240  */
 241 void
 242 segspt_free(struct seg  *seg)
 243 {
 244         struct spt_data *sptd = (struct spt_data *)seg->s_data;
 245 
 246         ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as));
 247 
 248         if (sptd != NULL) {
 249                 if (sptd->spt_realsize)
 250                         segspt_free_pages(seg, seg->s_base, sptd->spt_realsize);
 251 
 252                 if (sptd->spt_ppa_lckcnt) {
 253                         kmem_free(sptd->spt_ppa_lckcnt,
 254                             sizeof (*sptd->spt_ppa_lckcnt)
 255                             * btopr(sptd->spt_amp->size));
 256                 }
 257                 kmem_free(sptd->spt_vp, sizeof (*sptd->spt_vp));
 258                 cv_destroy(&sptd->spt_cv);
 259                 mutex_destroy(&sptd->spt_lock);
 260                 kmem_free(sptd, sizeof (*sptd));
 261         }
 262 }
 263 
 264 /*ARGSUSED*/
 265 static int
 266 segspt_shmsync(struct seg *seg, caddr_t addr, size_t len, int attr,
 267     uint_t flags)
 268 {
 269         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
 270 
 271         return (0);
 272 }
 273 
 274 /*ARGSUSED*/
 275 static size_t
 276 segspt_shmincore(struct seg *seg, caddr_t addr, size_t len, char *vec)
 277 {
 278         caddr_t eo_seg;
 279         pgcnt_t npages;
 280         struct shm_data *shmd = (struct shm_data *)seg->s_data;
 281         struct seg      *sptseg;
 282         struct spt_data *sptd;
 283 
 284         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
 285 #ifdef lint
 286         seg = seg;
 287 #endif
 288         sptseg = shmd->shm_sptseg;
 289         sptd = sptseg->s_data;
 290 
 291         if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
 292                 eo_seg = addr + len;
 293                 while (addr < eo_seg) {
 294                         /* page exists, and it's locked. */
 295                         *vec++ = SEG_PAGE_INCORE | SEG_PAGE_LOCKED |
 296                             SEG_PAGE_ANON;
 297                         addr += PAGESIZE;
 298                 }
 299                 return (len);
 300         } else {
 301                 struct  anon_map *amp = shmd->shm_amp;
 302                 struct  anon    *ap;
 303                 page_t          *pp;
 304                 pgcnt_t         anon_index;
 305                 struct vnode    *vp;
 306                 u_offset_t      off;
 307                 ulong_t         i;
 308                 int             ret;
 309                 anon_sync_obj_t cookie;
 310 
 311                 addr = (caddr_t)((uintptr_t)addr & (uintptr_t)PAGEMASK);
 312                 anon_index = seg_page(seg, addr);
 313                 npages = btopr(len);
 314                 if (anon_index + npages > btopr(shmd->shm_amp->size)) {
 315                         return (EINVAL);
 316                 }
 317                 ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
 318                 for (i = 0; i < npages; i++, anon_index++) {
 319                         ret = 0;
 320                         anon_array_enter(amp, anon_index, &cookie);
 321                         ap = anon_get_ptr(amp->ahp, anon_index);
 322                         if (ap != NULL) {
 323                                 swap_xlate(ap, &vp, &off);
 324                                 anon_array_exit(&cookie);
 325                                 pp = page_lookup_nowait(vp, off, SE_SHARED);
 326                                 if (pp != NULL) {
 327                                         ret |= SEG_PAGE_INCORE | SEG_PAGE_ANON;
 328                                         page_unlock(pp);
 329                                 }
 330                         } else {
 331                                 anon_array_exit(&cookie);
 332                         }
 333                         if (shmd->shm_vpage[anon_index] & DISM_PG_LOCKED) {
 334                                 ret |= SEG_PAGE_LOCKED;
 335                         }
 336                         *vec++ = (char)ret;
 337                 }
 338                 ANON_LOCK_EXIT(&amp->a_rwlock);
 339                 return (len);
 340         }
 341 }
 342 
 343 static int
 344 segspt_unmap(struct seg *seg, caddr_t raddr, size_t ssize)
 345 {
 346         size_t share_size;
 347 
 348         ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as));
 349 
 350         /*
 351          * seg.s_size may have been rounded up to the largest page size
 352          * in shmat().
 353          * XXX This should be cleanedup. sptdestroy should take a length
 354          * argument which should be the same as sptcreate. Then
 355          * this rounding would not be needed (or is done in shm.c)
 356          * Only the check for full segment will be needed.
 357          *
 358          * XXX -- shouldn't raddr == 0 always? These tests don't seem
 359          * to be useful at all.
 360          */
 361         share_size = page_get_pagesize(seg->s_szc);
 362         ssize = P2ROUNDUP(ssize, share_size);
 363 
 364         if (raddr == seg->s_base && ssize == seg->s_size) {
 365                 seg_free(seg);
 366                 return (0);
 367         } else
 368                 return (EINVAL);
 369 }
 370 
 371 int
 372 segspt_create(struct seg *seg, caddr_t argsp)
 373 {
 374         int             err;
 375         caddr_t         addr = seg->s_base;
 376         struct spt_data *sptd;
 377         struct  segspt_crargs *sptcargs = (struct segspt_crargs *)argsp;
 378         struct anon_map *amp = sptcargs->amp;
 379         struct kshmid   *sp = amp->a_sp;
 380         struct  cred    *cred = CRED();
 381         ulong_t         i, j, anon_index = 0;
 382         pgcnt_t         npages = btopr(amp->size);
 383         struct vnode    *vp;
 384         page_t          **ppa;
 385         uint_t          hat_flags;
 386         size_t          pgsz;
 387         pgcnt_t         pgcnt;
 388         caddr_t         a;
 389         pgcnt_t         pidx;
 390         size_t          sz;
 391         proc_t          *procp = curproc;
 392         rctl_qty_t      lockedbytes = 0;
 393         kproject_t      *proj;
 394 
 395         /*
 396          * We are holding the a_lock on the underlying dummy as,
 397          * so we can make calls to the HAT layer.
 398          */
 399         ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as));
 400         ASSERT(sp != NULL);
 401 
 402 #ifdef DEBUG
 403         TNF_PROBE_2(segspt_create, "spt", /* CSTYLED */,
 404             tnf_opaque, addr, addr, tnf_ulong, len, seg->s_size);
 405 #endif
 406         if ((sptcargs->flags & SHM_PAGEABLE) == 0) {
 407                 if (err = anon_swap_adjust(npages))
 408                         return (err);
 409         }
 410         err = ENOMEM;
 411 
 412         if ((sptd = kmem_zalloc(sizeof (*sptd), KM_NOSLEEP)) == NULL)
 413                 goto out1;
 414 
 415         if ((sptcargs->flags & SHM_PAGEABLE) == 0) {
 416                 if ((ppa = kmem_zalloc(((sizeof (page_t *)) * npages),
 417                     KM_NOSLEEP)) == NULL)
 418                         goto out2;
 419         }
 420 
 421         mutex_init(&sptd->spt_lock, NULL, MUTEX_DEFAULT, NULL);
 422 
 423         if ((vp = kmem_zalloc(sizeof (*vp), KM_NOSLEEP)) == NULL)
 424                 goto out3;
 425 
 426         seg->s_ops = &segspt_ops;
 427         sptd->spt_vp = vp;
 428         sptd->spt_amp = amp;
 429         sptd->spt_prot = sptcargs->prot;
 430         sptd->spt_flags = sptcargs->flags;
 431         seg->s_data = (caddr_t)sptd;
 432         sptd->spt_ppa = NULL;
 433         sptd->spt_ppa_lckcnt = NULL;
 434         seg->s_szc = sptcargs->szc;
 435         cv_init(&sptd->spt_cv, NULL, CV_DEFAULT, NULL);
 436         sptd->spt_gen = 0;
 437 
 438         ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
 439         if (seg->s_szc > amp->a_szc) {
 440                 amp->a_szc = seg->s_szc;
 441         }
 442         ANON_LOCK_EXIT(&amp->a_rwlock);
 443 
 444         /*
 445          * Set policy to affect initial allocation of pages in
 446          * anon_map_createpages()
 447          */
 448         (void) lgrp_shm_policy_set(LGRP_MEM_POLICY_DEFAULT, amp, anon_index,
 449             NULL, 0, ptob(npages));
 450 
 451         if (sptcargs->flags & SHM_PAGEABLE) {
 452                 size_t  share_sz;
 453                 pgcnt_t new_npgs, more_pgs;
 454                 struct anon_hdr *nahp;
 455                 zone_t *zone;
 456 
 457                 share_sz = page_get_pagesize(seg->s_szc);
 458                 if (!IS_P2ALIGNED(amp->size, share_sz)) {
 459                         /*
 460                          * We are rounding up the size of the anon array
 461                          * on 4 M boundary because we always create 4 M
 462                          * of page(s) when locking, faulting pages and we
 463                          * don't have to check for all corner cases e.g.
 464                          * if there is enough space to allocate 4 M
 465                          * page.
 466                          */
 467                         new_npgs = btop(P2ROUNDUP(amp->size, share_sz));
 468                         more_pgs = new_npgs - npages;
 469 
 470                         /*
 471                          * The zone will never be NULL, as a fully created
 472                          * shm always has an owning zone.
 473                          */
 474                         zone = sp->shm_perm.ipc_zone_ref.zref_zone;
 475                         ASSERT(zone != NULL);
 476                         if (anon_resv_zone(ptob(more_pgs), zone) == 0) {
 477                                 err = ENOMEM;
 478                                 goto out4;
 479                         }
 480 
 481                         nahp = anon_create(new_npgs, ANON_SLEEP);
 482                         ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
 483                         (void) anon_copy_ptr(amp->ahp, 0, nahp, 0, npages,
 484                             ANON_SLEEP);
 485                         anon_release(amp->ahp, npages);
 486                         amp->ahp = nahp;
 487                         ASSERT(amp->swresv == ptob(npages));
 488                         amp->swresv = amp->size = ptob(new_npgs);
 489                         ANON_LOCK_EXIT(&amp->a_rwlock);
 490                         npages = new_npgs;
 491                 }
 492 
 493                 sptd->spt_ppa_lckcnt = kmem_zalloc(npages *
 494                     sizeof (*sptd->spt_ppa_lckcnt), KM_SLEEP);
 495                 sptd->spt_pcachecnt = 0;
 496                 sptd->spt_realsize = ptob(npages);
 497                 sptcargs->seg_spt = seg;
 498                 return (0);
 499         }
 500 
 501         /*
 502          * get array of pages for each anon slot in amp
 503          */
 504         if ((err = anon_map_createpages(amp, anon_index, ptob(npages), ppa,
 505             seg, addr, S_CREATE, cred)) != 0)
 506                 goto out4;
 507 
 508         mutex_enter(&sp->shm_mlock);
 509 
 510         /* May be partially locked, so, count bytes to charge for locking */
 511         for (i = 0; i < npages; i++)
 512                 if (ppa[i]->p_lckcnt == 0)
 513                         lockedbytes += PAGESIZE;
 514 
 515         proj = sp->shm_perm.ipc_proj;
 516 
 517         if (lockedbytes > 0) {
 518                 mutex_enter(&procp->p_lock);
 519                 if (rctl_incr_locked_mem(procp, proj, lockedbytes, 0)) {
 520                         mutex_exit(&procp->p_lock);
 521                         mutex_exit(&sp->shm_mlock);
 522                         for (i = 0; i < npages; i++)
 523                                 page_unlock(ppa[i]);
 524                         err = ENOMEM;
 525                         goto out4;
 526                 }
 527                 mutex_exit(&procp->p_lock);
 528         }
 529 
 530         /*
 531          * addr is initial address corresponding to the first page on ppa list
 532          */
 533         for (i = 0; i < npages; i++) {
 534                 /* attempt to lock all pages */
 535                 if (page_pp_lock(ppa[i], 0, 1) == 0) {
 536                         /*
 537                          * if unable to lock any page, unlock all
 538                          * of them and return error
 539                          */
 540                         for (j = 0; j < i; j++)
 541                                 page_pp_unlock(ppa[j], 0, 1);
 542                         for (i = 0; i < npages; i++)
 543                                 page_unlock(ppa[i]);
 544                         rctl_decr_locked_mem(NULL, proj, lockedbytes, 0);
 545                         mutex_exit(&sp->shm_mlock);
 546                         err = ENOMEM;
 547                         goto out4;
 548                 }
 549         }
 550         mutex_exit(&sp->shm_mlock);
 551 
 552         /*
 553          * Some platforms assume that ISM mappings are HAT_LOAD_LOCK
 554          * for the entire life of the segment. For example platforms
 555          * that do not support Dynamic Reconfiguration.
 556          */
 557         hat_flags = HAT_LOAD_SHARE;
 558         if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, NULL))
 559                 hat_flags |= HAT_LOAD_LOCK;
 560 
 561         /*
 562          * Load translations one lare page at a time
 563          * to make sure we don't create mappings bigger than
 564          * segment's size code in case underlying pages
 565          * are shared with segvn's segment that uses bigger
 566          * size code than we do.
 567          */
 568         pgsz = page_get_pagesize(seg->s_szc);
 569         pgcnt = page_get_pagecnt(seg->s_szc);
 570         for (a = addr, pidx = 0; pidx < npages; a += pgsz, pidx += pgcnt) {
 571                 sz = MIN(pgsz, ptob(npages - pidx));
 572                 hat_memload_array(seg->s_as->a_hat, a, sz,
 573                     &ppa[pidx], sptd->spt_prot, hat_flags);
 574         }
 575 
 576         /*
 577          * On platforms that do not support HAT_DYNAMIC_ISM_UNMAP,
 578          * we will leave the pages locked SE_SHARED for the life
 579          * of the ISM segment. This will prevent any calls to
 580          * hat_pageunload() on this ISM segment for those platforms.
 581          */
 582         if (!(hat_flags & HAT_LOAD_LOCK)) {
 583                 /*
 584                  * On platforms that support HAT_DYNAMIC_ISM_UNMAP,
 585                  * we no longer need to hold the SE_SHARED lock on the pages,
 586                  * since L_PAGELOCK and F_SOFTLOCK calls will grab the
 587                  * SE_SHARED lock on the pages as necessary.
 588                  */
 589                 for (i = 0; i < npages; i++)
 590                         page_unlock(ppa[i]);
 591         }
 592         sptd->spt_pcachecnt = 0;
 593         kmem_free(ppa, ((sizeof (page_t *)) * npages));
 594         sptd->spt_realsize = ptob(npages);
 595         atomic_add_long(&spt_used, npages);
 596         sptcargs->seg_spt = seg;
 597         return (0);
 598 
 599 out4:
 600         seg->s_data = NULL;
 601         kmem_free(vp, sizeof (*vp));
 602         cv_destroy(&sptd->spt_cv);
 603 out3:
 604         mutex_destroy(&sptd->spt_lock);
 605         if ((sptcargs->flags & SHM_PAGEABLE) == 0)
 606                 kmem_free(ppa, (sizeof (*ppa) * npages));
 607 out2:
 608         kmem_free(sptd, sizeof (*sptd));
 609 out1:
 610         if ((sptcargs->flags & SHM_PAGEABLE) == 0)
 611                 anon_swap_restore(npages);
 612         return (err);
 613 }
 614 
 615 /*ARGSUSED*/
 616 void
 617 segspt_free_pages(struct seg *seg, caddr_t addr, size_t len)
 618 {
 619         struct page     *pp;
 620         struct spt_data *sptd = (struct spt_data *)seg->s_data;
 621         pgcnt_t         npages;
 622         ulong_t         anon_idx;
 623         struct anon_map *amp;
 624         struct anon     *ap;
 625         struct vnode    *vp;
 626         u_offset_t      off;
 627         uint_t          hat_flags;
 628         int             root = 0;
 629         pgcnt_t         pgs, curnpgs = 0;
 630         page_t          *rootpp;
 631         rctl_qty_t      unlocked_bytes = 0;
 632         kproject_t      *proj;
 633         kshmid_t        *sp;
 634 
 635         ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as));
 636 
 637         len = P2ROUNDUP(len, PAGESIZE);
 638 
 639         npages = btop(len);
 640 
 641         hat_flags = HAT_UNLOAD_UNLOCK | HAT_UNLOAD_UNMAP;
 642         if ((hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) ||
 643             (sptd->spt_flags & SHM_PAGEABLE)) {
 644                 hat_flags = HAT_UNLOAD_UNMAP;
 645         }
 646 
 647         hat_unload(seg->s_as->a_hat, addr, len, hat_flags);
 648 
 649         amp = sptd->spt_amp;
 650         if (sptd->spt_flags & SHM_PAGEABLE)
 651                 npages = btop(amp->size);
 652 
 653         ASSERT(amp != NULL);
 654 
 655         if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
 656                 sp = amp->a_sp;
 657                 proj = sp->shm_perm.ipc_proj;
 658                 mutex_enter(&sp->shm_mlock);
 659         }
 660         for (anon_idx = 0; anon_idx < npages; anon_idx++) {
 661                 if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
 662                         if ((ap = anon_get_ptr(amp->ahp, anon_idx)) == NULL) {
 663                                 panic("segspt_free_pages: null app");
 664                                 /*NOTREACHED*/
 665                         }
 666                 } else {
 667                         if ((ap = anon_get_next_ptr(amp->ahp, &anon_idx))
 668                             == NULL)
 669                                 continue;
 670                 }
 671                 ASSERT(ANON_ISBUSY(anon_get_slot(amp->ahp, anon_idx)) == 0);
 672                 swap_xlate(ap, &vp, &off);
 673 
 674                 /*
 675                  * If this platform supports HAT_DYNAMIC_ISM_UNMAP,
 676                  * the pages won't be having SE_SHARED lock at this
 677                  * point.
 678                  *
 679                  * On platforms that do not support HAT_DYNAMIC_ISM_UNMAP,
 680                  * the pages are still held SE_SHARED locked from the
 681                  * original segspt_create()
 682                  *
 683                  * Our goal is to get SE_EXCL lock on each page, remove
 684                  * permanent lock on it and invalidate the page.
 685                  */
 686                 if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
 687                         if (hat_flags == HAT_UNLOAD_UNMAP)
 688                                 pp = page_lookup(vp, off, SE_EXCL);
 689                         else {
 690                                 if ((pp = page_find(vp, off)) == NULL) {
 691                                         panic("segspt_free_pages: "
 692                                             "page not locked");
 693                                         /*NOTREACHED*/
 694                                 }
 695                                 if (!page_tryupgrade(pp)) {
 696                                         page_unlock(pp);
 697                                         pp = page_lookup(vp, off, SE_EXCL);
 698                                 }
 699                         }
 700                         if (pp == NULL) {
 701                                 panic("segspt_free_pages: "
 702                                     "page not in the system");
 703                                 /*NOTREACHED*/
 704                         }
 705                         ASSERT(pp->p_lckcnt > 0);
 706                         page_pp_unlock(pp, 0, 1);
 707                         if (pp->p_lckcnt == 0)
 708                                 unlocked_bytes += PAGESIZE;
 709                 } else {
 710                         if ((pp = page_lookup(vp, off, SE_EXCL)) == NULL)
 711                                 continue;
 712                 }
 713                 /*
 714                  * It's logical to invalidate the pages here as in most cases
 715                  * these were created by segspt.
 716                  */
 717                 if (pp->p_szc != 0) {
 718                         if (root == 0) {
 719                                 ASSERT(curnpgs == 0);
 720                                 root = 1;
 721                                 rootpp = pp;
 722                                 pgs = curnpgs = page_get_pagecnt(pp->p_szc);
 723                                 ASSERT(pgs > 1);
 724                                 ASSERT(IS_P2ALIGNED(pgs, pgs));
 725                                 ASSERT(!(page_pptonum(pp) & (pgs - 1)));
 726                                 curnpgs--;
 727                         } else if ((page_pptonum(pp) & (pgs - 1)) == pgs - 1) {
 728                                 ASSERT(curnpgs == 1);
 729                                 ASSERT(page_pptonum(pp) ==
 730                                     page_pptonum(rootpp) + (pgs - 1));
 731                                 page_destroy_pages(rootpp);
 732                                 root = 0;
 733                                 curnpgs = 0;
 734                         } else {
 735                                 ASSERT(curnpgs > 1);
 736                                 ASSERT(page_pptonum(pp) ==
 737                                     page_pptonum(rootpp) + (pgs - curnpgs));
 738                                 curnpgs--;
 739                         }
 740                 } else {
 741                         if (root != 0 || curnpgs != 0) {
 742                                 panic("segspt_free_pages: bad large page");
 743                                 /*NOTREACHED*/
 744                         }
 745                         /*
 746                          * Before destroying the pages, we need to take care
 747                          * of the rctl locked memory accounting. For that
 748                          * we need to calculte the unlocked_bytes.
 749                          */
 750                         if (pp->p_lckcnt > 0)
 751                                 unlocked_bytes += PAGESIZE;
 752                         /*LINTED: constant in conditional context */
 753                         VN_DISPOSE(pp, B_INVAL, 0, kcred);
 754                 }
 755         }
 756         if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
 757                 if (unlocked_bytes > 0)
 758                         rctl_decr_locked_mem(NULL, proj, unlocked_bytes, 0);
 759                 mutex_exit(&sp->shm_mlock);
 760         }
 761         if (root != 0 || curnpgs != 0) {
 762                 panic("segspt_free_pages: bad large page");
 763                 /*NOTREACHED*/
 764         }
 765 
 766         /*
 767          * mark that pages have been released
 768          */
 769         sptd->spt_realsize = 0;
 770 
 771         if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
 772                 atomic_add_long(&spt_used, -npages);
 773                 anon_swap_restore(npages);
 774         }
 775 }
 776 
 777 /*
 778  * Get memory allocation policy info for specified address in given segment
 779  */
 780 static lgrp_mem_policy_info_t *
 781 segspt_getpolicy(struct seg *seg, caddr_t addr)
 782 {
 783         struct anon_map         *amp;
 784         ulong_t                 anon_index;
 785         lgrp_mem_policy_info_t  *policy_info;
 786         struct spt_data         *spt_data;
 787 
 788         ASSERT(seg != NULL);
 789 
 790         /*
 791          * Get anon_map from segspt
 792          *
 793          * Assume that no lock needs to be held on anon_map, since
 794          * it should be protected by its reference count which must be
 795          * nonzero for an existing segment
 796          * Need to grab readers lock on policy tree though
 797          */
 798         spt_data = (struct spt_data *)seg->s_data;
 799         if (spt_data == NULL)
 800                 return (NULL);
 801         amp = spt_data->spt_amp;
 802         ASSERT(amp->refcnt != 0);
 803 
 804         /*
 805          * Get policy info
 806          *
 807          * Assume starting anon index of 0
 808          */
 809         anon_index = seg_page(seg, addr);
 810         policy_info = lgrp_shm_policy_get(amp, anon_index, NULL, 0);
 811 
 812         return (policy_info);
 813 }
 814 
 815 /*
 816  * DISM only.
 817  * Return locked pages over a given range.
 818  *
 819  * We will cache all DISM locked pages and save the pplist for the
 820  * entire segment in the ppa field of the underlying DISM segment structure.
 821  * Later, during a call to segspt_reclaim() we will use this ppa array
 822  * to page_unlock() all of the pages and then we will free this ppa list.
 823  */
 824 /*ARGSUSED*/
 825 static int
 826 segspt_dismpagelock(struct seg *seg, caddr_t addr, size_t len,
 827     struct page ***ppp, enum lock_type type, enum seg_rw rw)
 828 {
 829         struct  shm_data *shmd = (struct shm_data *)seg->s_data;
 830         struct  seg     *sptseg = shmd->shm_sptseg;
 831         struct  spt_data *sptd = sptseg->s_data;
 832         pgcnt_t pg_idx, npages, tot_npages, npgs;
 833         struct  page **pplist, **pl, **ppa, *pp;
 834         struct  anon_map *amp;
 835         spgcnt_t        an_idx;
 836         int     ret = ENOTSUP;
 837         uint_t  pl_built = 0;
 838         struct  anon *ap;
 839         struct  vnode *vp;
 840         u_offset_t off;
 841         pgcnt_t claim_availrmem = 0;
 842         uint_t  szc;
 843 
 844         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
 845         ASSERT(type == L_PAGELOCK || type == L_PAGEUNLOCK);
 846 
 847         /*
 848          * We want to lock/unlock the entire ISM segment. Therefore,
 849          * we will be using the underlying sptseg and it's base address
 850          * and length for the caching arguments.
 851          */
 852         ASSERT(sptseg);
 853         ASSERT(sptd);
 854 
 855         pg_idx = seg_page(seg, addr);
 856         npages = btopr(len);
 857 
 858         /*
 859          * check if the request is larger than number of pages covered
 860          * by amp
 861          */
 862         if (pg_idx + npages > btopr(sptd->spt_amp->size)) {
 863                 *ppp = NULL;
 864                 return (ENOTSUP);
 865         }
 866 
 867         if (type == L_PAGEUNLOCK) {
 868                 ASSERT(sptd->spt_ppa != NULL);
 869 
 870                 seg_pinactive(seg, NULL, seg->s_base, sptd->spt_amp->size,
 871                     sptd->spt_ppa, S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
 872 
 873                 /*
 874                  * If someone is blocked while unmapping, we purge
 875                  * segment page cache and thus reclaim pplist synchronously
 876                  * without waiting for seg_pasync_thread. This speeds up
 877                  * unmapping in cases where munmap(2) is called, while
 878                  * raw async i/o is still in progress or where a thread
 879                  * exits on data fault in a multithreaded application.
 880                  */
 881                 if ((sptd->spt_flags & DISM_PPA_CHANGED) ||
 882                     (AS_ISUNMAPWAIT(seg->s_as) &&
 883                     shmd->shm_softlockcnt > 0)) {
 884                         segspt_purge(seg);
 885                 }
 886                 return (0);
 887         }
 888 
 889         /* The L_PAGELOCK case ... */
 890 
 891         if (sptd->spt_flags & DISM_PPA_CHANGED) {
 892                 segspt_purge(seg);
 893                 /*
 894                  * for DISM ppa needs to be rebuild since
 895                  * number of locked pages could be changed
 896                  */
 897                 *ppp = NULL;
 898                 return (ENOTSUP);
 899         }
 900 
 901         /*
 902          * First try to find pages in segment page cache, without
 903          * holding the segment lock.
 904          */
 905         pplist = seg_plookup(seg, NULL, seg->s_base, sptd->spt_amp->size,
 906             S_WRITE, SEGP_FORCE_WIRED);
 907         if (pplist != NULL) {
 908                 ASSERT(sptd->spt_ppa != NULL);
 909                 ASSERT(sptd->spt_ppa == pplist);
 910                 ppa = sptd->spt_ppa;
 911                 for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
 912                         if (ppa[an_idx] == NULL) {
 913                                 seg_pinactive(seg, NULL, seg->s_base,
 914                                     sptd->spt_amp->size, ppa,
 915                                     S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
 916                                 *ppp = NULL;
 917                                 return (ENOTSUP);
 918                         }
 919                         if ((szc = ppa[an_idx]->p_szc) != 0) {
 920                                 npgs = page_get_pagecnt(szc);
 921                                 an_idx = P2ROUNDUP(an_idx + 1, npgs);
 922                         } else {
 923                                 an_idx++;
 924                         }
 925                 }
 926                 /*
 927                  * Since we cache the entire DISM segment, we want to
 928                  * set ppp to point to the first slot that corresponds
 929                  * to the requested addr, i.e. pg_idx.
 930                  */
 931                 *ppp = &(sptd->spt_ppa[pg_idx]);
 932                 return (0);
 933         }
 934 
 935         mutex_enter(&sptd->spt_lock);
 936         /*
 937          * try to find pages in segment page cache with mutex
 938          */
 939         pplist = seg_plookup(seg, NULL, seg->s_base, sptd->spt_amp->size,
 940             S_WRITE, SEGP_FORCE_WIRED);
 941         if (pplist != NULL) {
 942                 ASSERT(sptd->spt_ppa != NULL);
 943                 ASSERT(sptd->spt_ppa == pplist);
 944                 ppa = sptd->spt_ppa;
 945                 for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
 946                         if (ppa[an_idx] == NULL) {
 947                                 mutex_exit(&sptd->spt_lock);
 948                                 seg_pinactive(seg, NULL, seg->s_base,
 949                                     sptd->spt_amp->size, ppa,
 950                                     S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
 951                                 *ppp = NULL;
 952                                 return (ENOTSUP);
 953                         }
 954                         if ((szc = ppa[an_idx]->p_szc) != 0) {
 955                                 npgs = page_get_pagecnt(szc);
 956                                 an_idx = P2ROUNDUP(an_idx + 1, npgs);
 957                         } else {
 958                                 an_idx++;
 959                         }
 960                 }
 961                 /*
 962                  * Since we cache the entire DISM segment, we want to
 963                  * set ppp to point to the first slot that corresponds
 964                  * to the requested addr, i.e. pg_idx.
 965                  */
 966                 mutex_exit(&sptd->spt_lock);
 967                 *ppp = &(sptd->spt_ppa[pg_idx]);
 968                 return (0);
 969         }
 970         if (seg_pinsert_check(seg, NULL, seg->s_base, sptd->spt_amp->size,
 971             SEGP_FORCE_WIRED) == SEGP_FAIL) {
 972                 mutex_exit(&sptd->spt_lock);
 973                 *ppp = NULL;
 974                 return (ENOTSUP);
 975         }
 976 
 977         /*
 978          * No need to worry about protections because DISM pages are always rw.
 979          */
 980         pl = pplist = NULL;
 981         amp = sptd->spt_amp;
 982 
 983         /*
 984          * Do we need to build the ppa array?
 985          */
 986         if (sptd->spt_ppa == NULL) {
 987                 pgcnt_t lpg_cnt = 0;
 988 
 989                 pl_built = 1;
 990                 tot_npages = btopr(sptd->spt_amp->size);
 991 
 992                 ASSERT(sptd->spt_pcachecnt == 0);
 993                 pplist = kmem_zalloc(sizeof (page_t *) * tot_npages, KM_SLEEP);
 994                 pl = pplist;
 995 
 996                 ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
 997                 for (an_idx = 0; an_idx < tot_npages; ) {
 998                         ap = anon_get_ptr(amp->ahp, an_idx);
 999                         /*
1000                          * Cache only mlocked pages. For large pages
1001                          * if one (constituent) page is mlocked
1002                          * all pages for that large page
1003                          * are cached also. This is for quick
1004                          * lookups of ppa array;
1005                          */
1006                         if ((ap != NULL) && (lpg_cnt != 0 ||
1007                             (sptd->spt_ppa_lckcnt[an_idx] != 0))) {
1008 
1009                                 swap_xlate(ap, &vp, &off);
1010                                 pp = page_lookup(vp, off, SE_SHARED);
1011                                 ASSERT(pp != NULL);
1012                                 if (lpg_cnt == 0) {
1013                                         lpg_cnt++;
1014                                         /*
1015                                          * For a small page, we are done --
1016                                          * lpg_count is reset to 0 below.
1017                                          *
1018                                          * For a large page, we are guaranteed
1019                                          * to find the anon structures of all
1020                                          * constituent pages and a non-zero
1021                                          * lpg_cnt ensures that we don't test
1022                                          * for mlock for these. We are done
1023                                          * when lpg_count reaches (npgs + 1).
1024                                          * If we are not the first constituent
1025                                          * page, restart at the first one.
1026                                          */
1027                                         npgs = page_get_pagecnt(pp->p_szc);
1028                                         if (!IS_P2ALIGNED(an_idx, npgs)) {
1029                                                 an_idx = P2ALIGN(an_idx, npgs);
1030                                                 page_unlock(pp);
1031                                                 continue;
1032                                         }
1033                                 }
1034                                 if (++lpg_cnt > npgs)
1035                                         lpg_cnt = 0;
1036 
1037                                 /*
1038                                  * availrmem is decremented only
1039                                  * for unlocked pages
1040                                  */
1041                                 if (sptd->spt_ppa_lckcnt[an_idx] == 0)
1042                                         claim_availrmem++;
1043                                 pplist[an_idx] = pp;
1044                         }
1045                         an_idx++;
1046                 }
1047                 ANON_LOCK_EXIT(&amp->a_rwlock);
1048 
1049                 if (claim_availrmem) {
1050                         mutex_enter(&freemem_lock);
1051                         if (availrmem < tune.t_minarmem + claim_availrmem) {
1052                                 mutex_exit(&freemem_lock);
1053                                 ret = ENOTSUP;
1054                                 claim_availrmem = 0;
1055                                 goto insert_fail;
1056                         } else {
1057                                 availrmem -= claim_availrmem;
1058                         }
1059                         mutex_exit(&freemem_lock);
1060                 }
1061 
1062                 sptd->spt_ppa = pl;
1063         } else {
1064                 /*
1065                  * We already have a valid ppa[].
1066                  */
1067                 pl = sptd->spt_ppa;
1068         }
1069 
1070         ASSERT(pl != NULL);
1071 
1072         ret = seg_pinsert(seg, NULL, seg->s_base, sptd->spt_amp->size,
1073             sptd->spt_amp->size, pl, S_WRITE, SEGP_FORCE_WIRED,
1074             segspt_reclaim);
1075         if (ret == SEGP_FAIL) {
1076                 /*
1077                  * seg_pinsert failed. We return
1078                  * ENOTSUP, so that the as_pagelock() code will
1079                  * then try the slower F_SOFTLOCK path.
1080                  */
1081                 if (pl_built) {
1082                         /*
1083                          * No one else has referenced the ppa[].
1084                          * We created it and we need to destroy it.
1085                          */
1086                         sptd->spt_ppa = NULL;
1087                 }
1088                 ret = ENOTSUP;
1089                 goto insert_fail;
1090         }
1091 
1092         /*
1093          * In either case, we increment softlockcnt on the 'real' segment.
1094          */
1095         sptd->spt_pcachecnt++;
1096         atomic_inc_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
1097 
1098         ppa = sptd->spt_ppa;
1099         for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
1100                 if (ppa[an_idx] == NULL) {
1101                         mutex_exit(&sptd->spt_lock);
1102                         seg_pinactive(seg, NULL, seg->s_base,
1103                             sptd->spt_amp->size,
1104                             pl, S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
1105                         *ppp = NULL;
1106                         return (ENOTSUP);
1107                 }
1108                 if ((szc = ppa[an_idx]->p_szc) != 0) {
1109                         npgs = page_get_pagecnt(szc);
1110                         an_idx = P2ROUNDUP(an_idx + 1, npgs);
1111                 } else {
1112                         an_idx++;
1113                 }
1114         }
1115         /*
1116          * We can now drop the sptd->spt_lock since the ppa[]
1117          * exists and we have incremented pacachecnt.
1118          */
1119         mutex_exit(&sptd->spt_lock);
1120 
1121         /*
1122          * Since we cache the entire segment, we want to
1123          * set ppp to point to the first slot that corresponds
1124          * to the requested addr, i.e. pg_idx.
1125          */
1126         *ppp = &(sptd->spt_ppa[pg_idx]);
1127         return (0);
1128 
1129 insert_fail:
1130         /*
1131          * We will only reach this code if we tried and failed.
1132          *
1133          * And we can drop the lock on the dummy seg, once we've failed
1134          * to set up a new ppa[].
1135          */
1136         mutex_exit(&sptd->spt_lock);
1137 
1138         if (pl_built) {
1139                 if (claim_availrmem) {
1140                         mutex_enter(&freemem_lock);
1141                         availrmem += claim_availrmem;
1142                         mutex_exit(&freemem_lock);
1143                 }
1144 
1145                 /*
1146                  * We created pl and we need to destroy it.
1147                  */
1148                 pplist = pl;
1149                 for (an_idx = 0; an_idx < tot_npages; an_idx++) {
1150                         if (pplist[an_idx] != NULL)
1151                                 page_unlock(pplist[an_idx]);
1152                 }
1153                 kmem_free(pl, sizeof (page_t *) * tot_npages);
1154         }
1155 
1156         if (shmd->shm_softlockcnt <= 0) {
1157                 if (AS_ISUNMAPWAIT(seg->s_as)) {
1158                         mutex_enter(&seg->s_as->a_contents);
1159                         if (AS_ISUNMAPWAIT(seg->s_as)) {
1160                                 AS_CLRUNMAPWAIT(seg->s_as);
1161                                 cv_broadcast(&seg->s_as->a_cv);
1162                         }
1163                         mutex_exit(&seg->s_as->a_contents);
1164                 }
1165         }
1166         *ppp = NULL;
1167         return (ret);
1168 }
1169 
1170 
1171 
1172 /*
1173  * return locked pages over a given range.
1174  *
1175  * We will cache the entire ISM segment and save the pplist for the
1176  * entire segment in the ppa field of the underlying ISM segment structure.
1177  * Later, during a call to segspt_reclaim() we will use this ppa array
1178  * to page_unlock() all of the pages and then we will free this ppa list.
1179  */
1180 /*ARGSUSED*/
1181 static int
1182 segspt_shmpagelock(struct seg *seg, caddr_t addr, size_t len,
1183     struct page ***ppp, enum lock_type type, enum seg_rw rw)
1184 {
1185         struct shm_data *shmd = (struct shm_data *)seg->s_data;
1186         struct seg      *sptseg = shmd->shm_sptseg;
1187         struct spt_data *sptd = sptseg->s_data;
1188         pgcnt_t np, page_index, npages;
1189         caddr_t a, spt_base;
1190         struct page **pplist, **pl, *pp;
1191         struct anon_map *amp;
1192         ulong_t anon_index;
1193         int ret = ENOTSUP;
1194         uint_t  pl_built = 0;
1195         struct anon *ap;
1196         struct vnode *vp;
1197         u_offset_t off;
1198 
1199         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
1200         ASSERT(type == L_PAGELOCK || type == L_PAGEUNLOCK);
1201 
1202 
1203         /*
1204          * We want to lock/unlock the entire ISM segment. Therefore,
1205          * we will be using the underlying sptseg and it's base address
1206          * and length for the caching arguments.
1207          */
1208         ASSERT(sptseg);
1209         ASSERT(sptd);
1210 
1211         if (sptd->spt_flags & SHM_PAGEABLE) {
1212                 return (segspt_dismpagelock(seg, addr, len, ppp, type, rw));
1213         }
1214 
1215         page_index = seg_page(seg, addr);
1216         npages = btopr(len);
1217 
1218         /*
1219          * check if the request is larger than number of pages covered
1220          * by amp
1221          */
1222         if (page_index + npages > btopr(sptd->spt_amp->size)) {
1223                 *ppp = NULL;
1224                 return (ENOTSUP);
1225         }
1226 
1227         if (type == L_PAGEUNLOCK) {
1228 
1229                 ASSERT(sptd->spt_ppa != NULL);
1230 
1231                 seg_pinactive(seg, NULL, seg->s_base, sptd->spt_amp->size,
1232                     sptd->spt_ppa, S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
1233 
1234                 /*
1235                  * If someone is blocked while unmapping, we purge
1236                  * segment page cache and thus reclaim pplist synchronously
1237                  * without waiting for seg_pasync_thread. This speeds up
1238                  * unmapping in cases where munmap(2) is called, while
1239                  * raw async i/o is still in progress or where a thread
1240                  * exits on data fault in a multithreaded application.
1241                  */
1242                 if (AS_ISUNMAPWAIT(seg->s_as) && (shmd->shm_softlockcnt > 0)) {
1243                         segspt_purge(seg);
1244                 }
1245                 return (0);
1246         }
1247 
1248         /* The L_PAGELOCK case... */
1249 
1250         /*
1251          * First try to find pages in segment page cache, without
1252          * holding the segment lock.
1253          */
1254         pplist = seg_plookup(seg, NULL, seg->s_base, sptd->spt_amp->size,
1255             S_WRITE, SEGP_FORCE_WIRED);
1256         if (pplist != NULL) {
1257                 ASSERT(sptd->spt_ppa == pplist);
1258                 ASSERT(sptd->spt_ppa[page_index]);
1259                 /*
1260                  * Since we cache the entire ISM segment, we want to
1261                  * set ppp to point to the first slot that corresponds
1262                  * to the requested addr, i.e. page_index.
1263                  */
1264                 *ppp = &(sptd->spt_ppa[page_index]);
1265                 return (0);
1266         }
1267 
1268         mutex_enter(&sptd->spt_lock);
1269 
1270         /*
1271          * try to find pages in segment page cache
1272          */
1273         pplist = seg_plookup(seg, NULL, seg->s_base, sptd->spt_amp->size,
1274             S_WRITE, SEGP_FORCE_WIRED);
1275         if (pplist != NULL) {
1276                 ASSERT(sptd->spt_ppa == pplist);
1277                 /*
1278                  * Since we cache the entire segment, we want to
1279                  * set ppp to point to the first slot that corresponds
1280                  * to the requested addr, i.e. page_index.
1281                  */
1282                 mutex_exit(&sptd->spt_lock);
1283                 *ppp = &(sptd->spt_ppa[page_index]);
1284                 return (0);
1285         }
1286 
1287         if (seg_pinsert_check(seg, NULL, seg->s_base, sptd->spt_amp->size,
1288             SEGP_FORCE_WIRED) == SEGP_FAIL) {
1289                 mutex_exit(&sptd->spt_lock);
1290                 *ppp = NULL;
1291                 return (ENOTSUP);
1292         }
1293 
1294         /*
1295          * No need to worry about protections because ISM pages
1296          * are always rw.
1297          */
1298         pl = pplist = NULL;
1299 
1300         /*
1301          * Do we need to build the ppa array?
1302          */
1303         if (sptd->spt_ppa == NULL) {
1304                 ASSERT(sptd->spt_ppa == pplist);
1305 
1306                 spt_base = sptseg->s_base;
1307                 pl_built = 1;
1308 
1309                 /*
1310                  * availrmem is decremented once during anon_swap_adjust()
1311                  * and is incremented during the anon_unresv(), which is
1312                  * called from shm_rm_amp() when the segment is destroyed.
1313                  */
1314                 amp = sptd->spt_amp;
1315                 ASSERT(amp != NULL);
1316 
1317                 /* pcachecnt is protected by sptd->spt_lock */
1318                 ASSERT(sptd->spt_pcachecnt == 0);
1319                 pplist = kmem_zalloc(sizeof (page_t *)
1320                     * btopr(sptd->spt_amp->size), KM_SLEEP);
1321                 pl = pplist;
1322 
1323                 anon_index = seg_page(sptseg, spt_base);
1324 
1325                 ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
1326                 for (a = spt_base; a < (spt_base + sptd->spt_amp->size);
1327                     a += PAGESIZE, anon_index++, pplist++) {
1328                         ap = anon_get_ptr(amp->ahp, anon_index);
1329                         ASSERT(ap != NULL);
1330                         swap_xlate(ap, &vp, &off);
1331                         pp = page_lookup(vp, off, SE_SHARED);
1332                         ASSERT(pp != NULL);
1333                         *pplist = pp;
1334                 }
1335                 ANON_LOCK_EXIT(&amp->a_rwlock);
1336 
1337                 if (a < (spt_base + sptd->spt_amp->size)) {
1338                         ret = ENOTSUP;
1339                         goto insert_fail;
1340                 }
1341                 sptd->spt_ppa = pl;
1342         } else {
1343                 /*
1344                  * We already have a valid ppa[].
1345                  */
1346                 pl = sptd->spt_ppa;
1347         }
1348 
1349         ASSERT(pl != NULL);
1350 
1351         ret = seg_pinsert(seg, NULL, seg->s_base, sptd->spt_amp->size,
1352             sptd->spt_amp->size, pl, S_WRITE, SEGP_FORCE_WIRED,
1353             segspt_reclaim);
1354         if (ret == SEGP_FAIL) {
1355                 /*
1356                  * seg_pinsert failed. We return
1357                  * ENOTSUP, so that the as_pagelock() code will
1358                  * then try the slower F_SOFTLOCK path.
1359                  */
1360                 if (pl_built) {
1361                         /*
1362                          * No one else has referenced the ppa[].
1363                          * We created it and we need to destroy it.
1364                          */
1365                         sptd->spt_ppa = NULL;
1366                 }
1367                 ret = ENOTSUP;
1368                 goto insert_fail;
1369         }
1370 
1371         /*
1372          * In either case, we increment softlockcnt on the 'real' segment.
1373          */
1374         sptd->spt_pcachecnt++;
1375         atomic_inc_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
1376 
1377         /*
1378          * We can now drop the sptd->spt_lock since the ppa[]
1379          * exists and we have incremented pacachecnt.
1380          */
1381         mutex_exit(&sptd->spt_lock);
1382 
1383         /*
1384          * Since we cache the entire segment, we want to
1385          * set ppp to point to the first slot that corresponds
1386          * to the requested addr, i.e. page_index.
1387          */
1388         *ppp = &(sptd->spt_ppa[page_index]);
1389         return (0);
1390 
1391 insert_fail:
1392         /*
1393          * We will only reach this code if we tried and failed.
1394          *
1395          * And we can drop the lock on the dummy seg, once we've failed
1396          * to set up a new ppa[].
1397          */
1398         mutex_exit(&sptd->spt_lock);
1399 
1400         if (pl_built) {
1401                 /*
1402                  * We created pl and we need to destroy it.
1403                  */
1404                 pplist = pl;
1405                 np = (((uintptr_t)(a - spt_base)) >> PAGESHIFT);
1406                 while (np) {
1407                         page_unlock(*pplist);
1408                         np--;
1409                         pplist++;
1410                 }
1411                 kmem_free(pl, sizeof (page_t *) * btopr(sptd->spt_amp->size));
1412         }
1413         if (shmd->shm_softlockcnt <= 0) {
1414                 if (AS_ISUNMAPWAIT(seg->s_as)) {
1415                         mutex_enter(&seg->s_as->a_contents);
1416                         if (AS_ISUNMAPWAIT(seg->s_as)) {
1417                                 AS_CLRUNMAPWAIT(seg->s_as);
1418                                 cv_broadcast(&seg->s_as->a_cv);
1419                         }
1420                         mutex_exit(&seg->s_as->a_contents);
1421                 }
1422         }
1423         *ppp = NULL;
1424         return (ret);
1425 }
1426 
1427 /*
1428  * purge any cached pages in the I/O page cache
1429  */
1430 static void
1431 segspt_purge(struct seg *seg)
1432 {
1433         seg_ppurge(seg, NULL, SEGP_FORCE_WIRED);
1434 }
1435 
1436 static int
1437 segspt_reclaim(void *ptag, caddr_t addr, size_t len, struct page **pplist,
1438     enum seg_rw rw, int async)
1439 {
1440         struct seg *seg = (struct seg *)ptag;
1441         struct  shm_data *shmd = (struct shm_data *)seg->s_data;
1442         struct  seg     *sptseg;
1443         struct  spt_data *sptd;
1444         pgcnt_t npages, i, free_availrmem = 0;
1445         int     done = 0;
1446 
1447 #ifdef lint
1448         addr = addr;
1449 #endif
1450         sptseg = shmd->shm_sptseg;
1451         sptd = sptseg->s_data;
1452         npages = (len >> PAGESHIFT);
1453         ASSERT(npages);
1454         ASSERT(sptd->spt_pcachecnt != 0);
1455         ASSERT(sptd->spt_ppa == pplist);
1456         ASSERT(npages == btopr(sptd->spt_amp->size));
1457         ASSERT(async || AS_LOCK_HELD(seg->s_as));
1458 
1459         /*
1460          * Acquire the lock on the dummy seg and destroy the
1461          * ppa array IF this is the last pcachecnt.
1462          */
1463         mutex_enter(&sptd->spt_lock);
1464         if (--sptd->spt_pcachecnt == 0) {
1465                 for (i = 0; i < npages; i++) {
1466                         if (pplist[i] == NULL) {
1467                                 continue;
1468                         }
1469                         if (rw == S_WRITE) {
1470                                 hat_setrefmod(pplist[i]);
1471                         } else {
1472                                 hat_setref(pplist[i]);
1473                         }
1474                         if ((sptd->spt_flags & SHM_PAGEABLE) &&
1475                             (sptd->spt_ppa_lckcnt[i] == 0))
1476                                 free_availrmem++;
1477                         page_unlock(pplist[i]);
1478                 }
1479                 if ((sptd->spt_flags & SHM_PAGEABLE) && free_availrmem) {
1480                         mutex_enter(&freemem_lock);
1481                         availrmem += free_availrmem;
1482                         mutex_exit(&freemem_lock);
1483                 }
1484                 /*
1485                  * Since we want to cach/uncache the entire ISM segment,
1486                  * we will track the pplist in a segspt specific field
1487                  * ppa, that is initialized at the time we add an entry to
1488                  * the cache.
1489                  */
1490                 ASSERT(sptd->spt_pcachecnt == 0);
1491                 kmem_free(pplist, sizeof (page_t *) * npages);
1492                 sptd->spt_ppa = NULL;
1493                 sptd->spt_flags &= ~DISM_PPA_CHANGED;
1494                 sptd->spt_gen++;
1495                 cv_broadcast(&sptd->spt_cv);
1496                 done = 1;
1497         }
1498         mutex_exit(&sptd->spt_lock);
1499 
1500         /*
1501          * If we are pcache async thread or called via seg_ppurge_wiredpp() we
1502          * may not hold AS lock (in this case async argument is not 0). This
1503          * means if softlockcnt drops to 0 after the decrement below address
1504          * space may get freed. We can't allow it since after softlock
1505          * derement to 0 we still need to access as structure for possible
1506          * wakeup of unmap waiters. To prevent the disappearance of as we take
1507          * this segment's shm_segfree_syncmtx. segspt_shmfree() also takes
1508          * this mutex as a barrier to make sure this routine completes before
1509          * segment is freed.
1510          *
1511          * The second complication we have to deal with in async case is a
1512          * possibility of missed wake up of unmap wait thread. When we don't
1513          * hold as lock here we may take a_contents lock before unmap wait
1514          * thread that was first to see softlockcnt was still not 0. As a
1515          * result we'll fail to wake up an unmap wait thread. To avoid this
1516          * race we set nounmapwait flag in as structure if we drop softlockcnt
1517          * to 0 if async is not 0.  unmapwait thread
1518          * will not block if this flag is set.
1519          */
1520         if (async)
1521                 mutex_enter(&shmd->shm_segfree_syncmtx);
1522 
1523         /*
1524          * Now decrement softlockcnt.
1525          */
1526         ASSERT(shmd->shm_softlockcnt > 0);
1527         atomic_dec_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
1528 
1529         if (shmd->shm_softlockcnt <= 0) {
1530                 if (async || AS_ISUNMAPWAIT(seg->s_as)) {
1531                         mutex_enter(&seg->s_as->a_contents);
1532                         if (async)
1533                                 AS_SETNOUNMAPWAIT(seg->s_as);
1534                         if (AS_ISUNMAPWAIT(seg->s_as)) {
1535                                 AS_CLRUNMAPWAIT(seg->s_as);
1536                                 cv_broadcast(&seg->s_as->a_cv);
1537                         }
1538                         mutex_exit(&seg->s_as->a_contents);
1539                 }
1540         }
1541 
1542         if (async)
1543                 mutex_exit(&shmd->shm_segfree_syncmtx);
1544 
1545         return (done);
1546 }
1547 
1548 /*
1549  * Do a F_SOFTUNLOCK call over the range requested.
1550  * The range must have already been F_SOFTLOCK'ed.
1551  *
1552  * The calls to acquire and release the anon map lock mutex were
1553  * removed in order to avoid a deadly embrace during a DR
1554  * memory delete operation.  (Eg. DR blocks while waiting for a
1555  * exclusive lock on a page that is being used for kaio; the
1556  * thread that will complete the kaio and call segspt_softunlock
1557  * blocks on the anon map lock; another thread holding the anon
1558  * map lock blocks on another page lock via the segspt_shmfault
1559  * -> page_lookup -> page_lookup_create -> page_lock_es code flow.)
1560  *
1561  * The appropriateness of the removal is based upon the following:
1562  * 1. If we are holding a segment's reader lock and the page is held
1563  * shared, then the corresponding element in anonmap which points to
1564  * anon struct cannot change and there is no need to acquire the
1565  * anonymous map lock.
1566  * 2. Threads in segspt_softunlock have a reader lock on the segment
1567  * and already have the shared page lock, so we are guaranteed that
1568  * the anon map slot cannot change and therefore can call anon_get_ptr()
1569  * without grabbing the anonymous map lock.
1570  * 3. Threads that softlock a shared page break copy-on-write, even if
1571  * its a read.  Thus cow faults can be ignored with respect to soft
1572  * unlocking, since the breaking of cow means that the anon slot(s) will
1573  * not be shared.
1574  */
1575 static void
1576 segspt_softunlock(struct seg *seg, caddr_t sptseg_addr,
1577     size_t len, enum seg_rw rw)
1578 {
1579         struct shm_data *shmd = (struct shm_data *)seg->s_data;
1580         struct seg      *sptseg;
1581         struct spt_data *sptd;
1582         page_t *pp;
1583         caddr_t adr;
1584         struct vnode *vp;
1585         u_offset_t offset;
1586         ulong_t anon_index;
1587         struct anon_map *amp;           /* XXX - for locknest */
1588         struct anon *ap = NULL;
1589         pgcnt_t npages;
1590 
1591         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
1592 
1593         sptseg = shmd->shm_sptseg;
1594         sptd = sptseg->s_data;
1595 
1596         /*
1597          * Some platforms assume that ISM mappings are HAT_LOAD_LOCK
1598          * and therefore their pages are SE_SHARED locked
1599          * for the entire life of the segment.
1600          */
1601         if ((!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) &&
1602             ((sptd->spt_flags & SHM_PAGEABLE) == 0)) {
1603                 goto softlock_decrement;
1604         }
1605 
1606         /*
1607          * Any thread is free to do a page_find and
1608          * page_unlock() on the pages within this seg.
1609          *
1610          * We are already holding the as->a_lock on the user's
1611          * real segment, but we need to hold the a_lock on the
1612          * underlying dummy as. This is mostly to satisfy the
1613          * underlying HAT layer.
1614          */
1615         AS_LOCK_ENTER(sptseg->s_as, RW_READER);
1616         hat_unlock(sptseg->s_as->a_hat, sptseg_addr, len);
1617         AS_LOCK_EXIT(sptseg->s_as);
1618 
1619         amp = sptd->spt_amp;
1620         ASSERT(amp != NULL);
1621         anon_index = seg_page(sptseg, sptseg_addr);
1622 
1623         for (adr = sptseg_addr; adr < sptseg_addr + len; adr += PAGESIZE) {
1624                 ap = anon_get_ptr(amp->ahp, anon_index++);
1625                 ASSERT(ap != NULL);
1626                 swap_xlate(ap, &vp, &offset);
1627 
1628                 /*
1629                  * Use page_find() instead of page_lookup() to
1630                  * find the page since we know that it has a
1631                  * "shared" lock.
1632                  */
1633                 pp = page_find(vp, offset);
1634                 ASSERT(ap == anon_get_ptr(amp->ahp, anon_index - 1));
1635                 if (pp == NULL) {
1636                         panic("segspt_softunlock: "
1637                             "addr %p, ap %p, vp %p, off %llx",
1638                             (void *)adr, (void *)ap, (void *)vp, offset);
1639                         /*NOTREACHED*/
1640                 }
1641 
1642                 if (rw == S_WRITE) {
1643                         hat_setrefmod(pp);
1644                 } else if (rw != S_OTHER) {
1645                         hat_setref(pp);
1646                 }
1647                 page_unlock(pp);
1648         }
1649 
1650 softlock_decrement:
1651         npages = btopr(len);
1652         ASSERT(shmd->shm_softlockcnt >= npages);
1653         atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), -npages);
1654         if (shmd->shm_softlockcnt == 0) {
1655                 /*
1656                  * All SOFTLOCKS are gone. Wakeup any waiting
1657                  * unmappers so they can try again to unmap.
1658                  * Check for waiters first without the mutex
1659                  * held so we don't always grab the mutex on
1660                  * softunlocks.
1661                  */
1662                 if (AS_ISUNMAPWAIT(seg->s_as)) {
1663                         mutex_enter(&seg->s_as->a_contents);
1664                         if (AS_ISUNMAPWAIT(seg->s_as)) {
1665                                 AS_CLRUNMAPWAIT(seg->s_as);
1666                                 cv_broadcast(&seg->s_as->a_cv);
1667                         }
1668                         mutex_exit(&seg->s_as->a_contents);
1669                 }
1670         }
1671 }
1672 
1673 int
1674 segspt_shmattach(struct seg *seg, caddr_t *argsp)
1675 {
1676         struct shm_data *shmd_arg = (struct shm_data *)argsp;
1677         struct shm_data *shmd;
1678         struct anon_map *shm_amp = shmd_arg->shm_amp;
1679         struct spt_data *sptd;
1680         int error = 0;
1681 
1682         ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as));
1683 
1684         shmd = kmem_zalloc((sizeof (*shmd)), KM_NOSLEEP);
1685         if (shmd == NULL)
1686                 return (ENOMEM);
1687 
1688         shmd->shm_sptas = shmd_arg->shm_sptas;
1689         shmd->shm_amp = shm_amp;
1690         shmd->shm_sptseg = shmd_arg->shm_sptseg;
1691 
1692         (void) lgrp_shm_policy_set(LGRP_MEM_POLICY_DEFAULT, shm_amp, 0,
1693             NULL, 0, seg->s_size);
1694 
1695         mutex_init(&shmd->shm_segfree_syncmtx, NULL, MUTEX_DEFAULT, NULL);
1696 
1697         seg->s_data = (void *)shmd;
1698         seg->s_ops = &segspt_shmops;
1699         seg->s_szc = shmd->shm_sptseg->s_szc;
1700         sptd = shmd->shm_sptseg->s_data;
1701 
1702         if (sptd->spt_flags & SHM_PAGEABLE) {
1703                 if ((shmd->shm_vpage = kmem_zalloc(btopr(shm_amp->size),
1704                     KM_NOSLEEP)) == NULL) {
1705                         seg->s_data = (void *)NULL;
1706                         kmem_free(shmd, (sizeof (*shmd)));
1707                         return (ENOMEM);
1708                 }
1709                 shmd->shm_lckpgs = 0;
1710                 if (hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
1711                         if ((error = hat_share(seg->s_as->a_hat, seg->s_base,
1712                             shmd_arg->shm_sptas->a_hat, SEGSPTADDR,
1713                             seg->s_size, seg->s_szc)) != 0) {
1714                                 kmem_free(shmd->shm_vpage,
1715                                     btopr(shm_amp->size));
1716                         }
1717                 }
1718         } else {
1719                 error = hat_share(seg->s_as->a_hat, seg->s_base,
1720                     shmd_arg->shm_sptas->a_hat, SEGSPTADDR,
1721                     seg->s_size, seg->s_szc);
1722         }
1723         if (error) {
1724                 seg->s_szc = 0;
1725                 seg->s_data = (void *)NULL;
1726                 kmem_free(shmd, (sizeof (*shmd)));
1727         } else {
1728                 ANON_LOCK_ENTER(&shm_amp->a_rwlock, RW_WRITER);
1729                 shm_amp->refcnt++;
1730                 ANON_LOCK_EXIT(&shm_amp->a_rwlock);
1731         }
1732         return (error);
1733 }
1734 
1735 int
1736 segspt_shmunmap(struct seg *seg, caddr_t raddr, size_t ssize)
1737 {
1738         struct shm_data *shmd = (struct shm_data *)seg->s_data;
1739         int reclaim = 1;
1740 
1741         ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as));
1742 retry:
1743         if (shmd->shm_softlockcnt > 0) {
1744                 if (reclaim == 1) {
1745                         segspt_purge(seg);
1746                         reclaim = 0;
1747                         goto retry;
1748                 }
1749                 return (EAGAIN);
1750         }
1751 
1752         if (ssize != seg->s_size) {
1753 #ifdef DEBUG
1754                 cmn_err(CE_WARN, "Incompatible ssize %lx s_size %lx\n",
1755                     ssize, seg->s_size);
1756 #endif
1757                 return (EINVAL);
1758         }
1759 
1760         (void) segspt_shmlockop(seg, raddr, shmd->shm_amp->size, 0, MC_UNLOCK,
1761             NULL, 0);
1762         hat_unshare(seg->s_as->a_hat, raddr, ssize, seg->s_szc);
1763 
1764         seg_free(seg);
1765 
1766         return (0);
1767 }
1768 
1769 void
1770 segspt_shmfree(struct seg *seg)
1771 {
1772         struct shm_data *shmd = (struct shm_data *)seg->s_data;
1773         struct anon_map *shm_amp = shmd->shm_amp;
1774 
1775         ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as));
1776 
1777         (void) segspt_shmlockop(seg, seg->s_base, shm_amp->size, 0,
1778             MC_UNLOCK, NULL, 0);
1779 
1780         /*
1781          * Need to increment refcnt when attaching
1782          * and decrement when detaching because of dup().
1783          */
1784         ANON_LOCK_ENTER(&shm_amp->a_rwlock, RW_WRITER);
1785         shm_amp->refcnt--;
1786         ANON_LOCK_EXIT(&shm_amp->a_rwlock);
1787 
1788         if (shmd->shm_vpage) {       /* only for DISM */
1789                 kmem_free(shmd->shm_vpage, btopr(shm_amp->size));
1790                 shmd->shm_vpage = NULL;
1791         }
1792 
1793         /*
1794          * Take shm_segfree_syncmtx lock to let segspt_reclaim() finish if it's
1795          * still working with this segment without holding as lock.
1796          */
1797         ASSERT(shmd->shm_softlockcnt == 0);
1798         mutex_enter(&shmd->shm_segfree_syncmtx);
1799         mutex_destroy(&shmd->shm_segfree_syncmtx);
1800 
1801         kmem_free(shmd, sizeof (*shmd));
1802 }
1803 
1804 /*ARGSUSED*/
1805 int
1806 segspt_shmsetprot(struct seg *seg, caddr_t addr, size_t len, uint_t prot)
1807 {
1808         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
1809 
1810         /*
1811          * Shared page table is more than shared mapping.
1812          *  Individual process sharing page tables can't change prot
1813          *  because there is only one set of page tables.
1814          *  This will be allowed after private page table is
1815          *  supported.
1816          */
1817 /* need to return correct status error? */
1818         return (0);
1819 }
1820 
1821 
1822 faultcode_t
1823 segspt_dismfault(struct hat *hat, struct seg *seg, caddr_t addr,
1824     size_t len, enum fault_type type, enum seg_rw rw)
1825 {
1826         struct  shm_data        *shmd = (struct shm_data *)seg->s_data;
1827         struct  seg             *sptseg = shmd->shm_sptseg;
1828         struct  as              *curspt = shmd->shm_sptas;
1829         struct  spt_data        *sptd = sptseg->s_data;
1830         pgcnt_t npages;
1831         size_t  size;
1832         caddr_t segspt_addr, shm_addr;
1833         page_t  **ppa;
1834         int     i;
1835         ulong_t an_idx = 0;
1836         int     err = 0;
1837         int     dyn_ism_unmap = hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0);
1838         size_t  pgsz;
1839         pgcnt_t pgcnt;
1840         caddr_t a;
1841         pgcnt_t pidx;
1842 
1843 #ifdef lint
1844         hat = hat;
1845 #endif
1846         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
1847 
1848         /*
1849          * Because of the way spt is implemented
1850          * the realsize of the segment does not have to be
1851          * equal to the segment size itself. The segment size is
1852          * often in multiples of a page size larger than PAGESIZE.
1853          * The realsize is rounded up to the nearest PAGESIZE
1854          * based on what the user requested. This is a bit of
1855          * ungliness that is historical but not easily fixed
1856          * without re-designing the higher levels of ISM.
1857          */
1858         ASSERT(addr >= seg->s_base);
1859         if (((addr + len) - seg->s_base) > sptd->spt_realsize)
1860                 return (FC_NOMAP);
1861         /*
1862          * For all of the following cases except F_PROT, we need to
1863          * make any necessary adjustments to addr and len
1864          * and get all of the necessary page_t's into an array called ppa[].
1865          *
1866          * The code in shmat() forces base addr and len of ISM segment
1867          * to be aligned to largest page size supported. Therefore,
1868          * we are able to handle F_SOFTLOCK and F_INVAL calls in "large
1869          * pagesize" chunks. We want to make sure that we HAT_LOAD_LOCK
1870          * in large pagesize chunks, or else we will screw up the HAT
1871          * layer by calling hat_memload_array() with differing page sizes
1872          * over a given virtual range.
1873          */
1874         pgsz = page_get_pagesize(sptseg->s_szc);
1875         pgcnt = page_get_pagecnt(sptseg->s_szc);
1876         shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), pgsz);
1877         size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)), pgsz);
1878         npages = btopr(size);
1879 
1880         /*
1881          * Now we need to convert from addr in segshm to addr in segspt.
1882          */
1883         an_idx = seg_page(seg, shm_addr);
1884         segspt_addr = sptseg->s_base + ptob(an_idx);
1885 
1886         ASSERT((segspt_addr + ptob(npages)) <=
1887             (sptseg->s_base + sptd->spt_realsize));
1888         ASSERT(segspt_addr < (sptseg->s_base + sptseg->s_size));
1889 
1890         switch (type) {
1891 
1892         case F_SOFTLOCK:
1893 
1894                 atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), npages);
1895                 /*
1896                  * Fall through to the F_INVAL case to load up the hat layer
1897                  * entries with the HAT_LOAD_LOCK flag.
1898                  */
1899                 /* FALLTHRU */
1900         case F_INVAL:
1901 
1902                 if ((rw == S_EXEC) && !(sptd->spt_prot & PROT_EXEC))
1903                         return (FC_NOMAP);
1904 
1905                 ppa = kmem_zalloc(npages * sizeof (page_t *), KM_SLEEP);
1906 
1907                 err = spt_anon_getpages(sptseg, segspt_addr, size, ppa);
1908                 if (err != 0) {
1909                         if (type == F_SOFTLOCK) {
1910                                 atomic_add_long((ulong_t *)(
1911                                     &(shmd->shm_softlockcnt)), -npages);
1912                         }
1913                         goto dism_err;
1914                 }
1915                 AS_LOCK_ENTER(sptseg->s_as, RW_READER);
1916                 a = segspt_addr;
1917                 pidx = 0;
1918                 if (type == F_SOFTLOCK) {
1919 
1920                         /*
1921                          * Load up the translation keeping it
1922                          * locked and don't unlock the page.
1923                          */
1924                         for (; pidx < npages; a += pgsz, pidx += pgcnt) {
1925                                 hat_memload_array(sptseg->s_as->a_hat,
1926                                     a, pgsz, &ppa[pidx], sptd->spt_prot,
1927                                     HAT_LOAD_LOCK | HAT_LOAD_SHARE);
1928                         }
1929                 } else {
1930                         /*
1931                          * Migrate pages marked for migration
1932                          */
1933                         if (lgrp_optimizations())
1934                                 page_migrate(seg, shm_addr, ppa, npages);
1935 
1936                         for (; pidx < npages; a += pgsz, pidx += pgcnt) {
1937                                 hat_memload_array(sptseg->s_as->a_hat,
1938                                     a, pgsz, &ppa[pidx],
1939                                     sptd->spt_prot,
1940                                     HAT_LOAD_SHARE);
1941                         }
1942 
1943                         /*
1944                          * And now drop the SE_SHARED lock(s).
1945                          */
1946                         if (dyn_ism_unmap) {
1947                                 for (i = 0; i < npages; i++) {
1948                                         page_unlock(ppa[i]);
1949                                 }
1950                         }
1951                 }
1952 
1953                 if (!dyn_ism_unmap) {
1954                         if (hat_share(seg->s_as->a_hat, shm_addr,
1955                             curspt->a_hat, segspt_addr, ptob(npages),
1956                             seg->s_szc) != 0) {
1957                                 panic("hat_share err in DISM fault");
1958                                 /* NOTREACHED */
1959                         }
1960                         if (type == F_INVAL) {
1961                                 for (i = 0; i < npages; i++) {
1962                                         page_unlock(ppa[i]);
1963                                 }
1964                         }
1965                 }
1966                 AS_LOCK_EXIT(sptseg->s_as);
1967 dism_err:
1968                 kmem_free(ppa, npages * sizeof (page_t *));
1969                 return (err);
1970 
1971         case F_SOFTUNLOCK:
1972 
1973                 /*
1974                  * This is a bit ugly, we pass in the real seg pointer,
1975                  * but the segspt_addr is the virtual address within the
1976                  * dummy seg.
1977                  */
1978                 segspt_softunlock(seg, segspt_addr, size, rw);
1979                 return (0);
1980 
1981         case F_PROT:
1982 
1983                 /*
1984                  * This takes care of the unusual case where a user
1985                  * allocates a stack in shared memory and a register
1986                  * window overflow is written to that stack page before
1987                  * it is otherwise modified.
1988                  *
1989                  * We can get away with this because ISM segments are
1990                  * always rw. Other than this unusual case, there
1991                  * should be no instances of protection violations.
1992                  */
1993                 return (0);
1994 
1995         default:
1996 #ifdef DEBUG
1997                 panic("segspt_dismfault default type?");
1998 #else
1999                 return (FC_NOMAP);
2000 #endif
2001         }
2002 }
2003 
2004 
2005 faultcode_t
2006 segspt_shmfault(struct hat *hat, struct seg *seg, caddr_t addr,
2007     size_t len, enum fault_type type, enum seg_rw rw)
2008 {
2009         struct shm_data         *shmd = (struct shm_data *)seg->s_data;
2010         struct seg              *sptseg = shmd->shm_sptseg;
2011         struct as               *curspt = shmd->shm_sptas;
2012         struct spt_data         *sptd   = sptseg->s_data;
2013         pgcnt_t npages;
2014         size_t size;
2015         caddr_t sptseg_addr, shm_addr;
2016         page_t *pp, **ppa;
2017         int     i;
2018         u_offset_t offset;
2019         ulong_t anon_index = 0;
2020         struct vnode *vp;
2021         struct anon_map *amp;           /* XXX - for locknest */
2022         struct anon *ap = NULL;
2023         size_t          pgsz;
2024         pgcnt_t         pgcnt;
2025         caddr_t         a;
2026         pgcnt_t         pidx;
2027         size_t          sz;
2028 
2029 #ifdef lint
2030         hat = hat;
2031 #endif
2032 
2033         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
2034 
2035         if (sptd->spt_flags & SHM_PAGEABLE) {
2036                 return (segspt_dismfault(hat, seg, addr, len, type, rw));
2037         }
2038 
2039         /*
2040          * Because of the way spt is implemented
2041          * the realsize of the segment does not have to be
2042          * equal to the segment size itself. The segment size is
2043          * often in multiples of a page size larger than PAGESIZE.
2044          * The realsize is rounded up to the nearest PAGESIZE
2045          * based on what the user requested. This is a bit of
2046          * ungliness that is historical but not easily fixed
2047          * without re-designing the higher levels of ISM.
2048          */
2049         ASSERT(addr >= seg->s_base);
2050         if (((addr + len) - seg->s_base) > sptd->spt_realsize)
2051                 return (FC_NOMAP);
2052         /*
2053          * For all of the following cases except F_PROT, we need to
2054          * make any necessary adjustments to addr and len
2055          * and get all of the necessary page_t's into an array called ppa[].
2056          *
2057          * The code in shmat() forces base addr and len of ISM segment
2058          * to be aligned to largest page size supported. Therefore,
2059          * we are able to handle F_SOFTLOCK and F_INVAL calls in "large
2060          * pagesize" chunks. We want to make sure that we HAT_LOAD_LOCK
2061          * in large pagesize chunks, or else we will screw up the HAT
2062          * layer by calling hat_memload_array() with differing page sizes
2063          * over a given virtual range.
2064          */
2065         pgsz = page_get_pagesize(sptseg->s_szc);
2066         pgcnt = page_get_pagecnt(sptseg->s_szc);
2067         shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), pgsz);
2068         size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)), pgsz);
2069         npages = btopr(size);
2070 
2071         /*
2072          * Now we need to convert from addr in segshm to addr in segspt.
2073          */
2074         anon_index = seg_page(seg, shm_addr);
2075         sptseg_addr = sptseg->s_base + ptob(anon_index);
2076 
2077         /*
2078          * And now we may have to adjust npages downward if we have
2079          * exceeded the realsize of the segment or initial anon
2080          * allocations.
2081          */
2082         if ((sptseg_addr + ptob(npages)) >
2083             (sptseg->s_base + sptd->spt_realsize))
2084                 size = (sptseg->s_base + sptd->spt_realsize) - sptseg_addr;
2085 
2086         npages = btopr(size);
2087 
2088         ASSERT(sptseg_addr < (sptseg->s_base + sptseg->s_size));
2089         ASSERT((sptd->spt_flags & SHM_PAGEABLE) == 0);
2090 
2091         switch (type) {
2092 
2093         case F_SOFTLOCK:
2094 
2095                 /*
2096                  * availrmem is decremented once during anon_swap_adjust()
2097                  * and is incremented during the anon_unresv(), which is
2098                  * called from shm_rm_amp() when the segment is destroyed.
2099                  */
2100                 atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), npages);
2101                 /*
2102                  * Some platforms assume that ISM pages are SE_SHARED
2103                  * locked for the entire life of the segment.
2104                  */
2105                 if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0))
2106                         return (0);
2107                 /*
2108                  * Fall through to the F_INVAL case to load up the hat layer
2109                  * entries with the HAT_LOAD_LOCK flag.
2110                  */
2111 
2112                 /* FALLTHRU */
2113         case F_INVAL:
2114 
2115                 if ((rw == S_EXEC) && !(sptd->spt_prot & PROT_EXEC))
2116                         return (FC_NOMAP);
2117 
2118                 /*
2119                  * Some platforms that do NOT support DYNAMIC_ISM_UNMAP
2120                  * may still rely on this call to hat_share(). That
2121                  * would imply that those hat's can fault on a
2122                  * HAT_LOAD_LOCK translation, which would seem
2123                  * contradictory.
2124                  */
2125                 if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
2126                         if (hat_share(seg->s_as->a_hat, seg->s_base,
2127                             curspt->a_hat, sptseg->s_base,
2128                             sptseg->s_size, sptseg->s_szc) != 0) {
2129                                 panic("hat_share error in ISM fault");
2130                                 /*NOTREACHED*/
2131                         }
2132                         return (0);
2133                 }
2134                 ppa = kmem_zalloc(sizeof (page_t *) * npages, KM_SLEEP);
2135 
2136                 /*
2137                  * I see no need to lock the real seg,
2138                  * here, because all of our work will be on the underlying
2139                  * dummy seg.
2140                  *
2141                  * sptseg_addr and npages now account for large pages.
2142                  */
2143                 amp = sptd->spt_amp;
2144                 ASSERT(amp != NULL);
2145                 anon_index = seg_page(sptseg, sptseg_addr);
2146 
2147                 ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2148                 for (i = 0; i < npages; i++) {
2149                         ap = anon_get_ptr(amp->ahp, anon_index++);
2150                         ASSERT(ap != NULL);
2151                         swap_xlate(ap, &vp, &offset);
2152                         pp = page_lookup(vp, offset, SE_SHARED);
2153                         ASSERT(pp != NULL);
2154                         ppa[i] = pp;
2155                 }
2156                 ANON_LOCK_EXIT(&amp->a_rwlock);
2157                 ASSERT(i == npages);
2158 
2159                 /*
2160                  * We are already holding the as->a_lock on the user's
2161                  * real segment, but we need to hold the a_lock on the
2162                  * underlying dummy as. This is mostly to satisfy the
2163                  * underlying HAT layer.
2164                  */
2165                 AS_LOCK_ENTER(sptseg->s_as, RW_READER);
2166                 a = sptseg_addr;
2167                 pidx = 0;
2168                 if (type == F_SOFTLOCK) {
2169                         /*
2170                          * Load up the translation keeping it
2171                          * locked and don't unlock the page.
2172                          */
2173                         for (; pidx < npages; a += pgsz, pidx += pgcnt) {
2174                                 sz = MIN(pgsz, ptob(npages - pidx));
2175                                 hat_memload_array(sptseg->s_as->a_hat, a,
2176                                     sz, &ppa[pidx], sptd->spt_prot,
2177                                     HAT_LOAD_LOCK | HAT_LOAD_SHARE);
2178                         }
2179                 } else {
2180                         /*
2181                          * Migrate pages marked for migration.
2182                          */
2183                         if (lgrp_optimizations())
2184                                 page_migrate(seg, shm_addr, ppa, npages);
2185 
2186                         for (; pidx < npages; a += pgsz, pidx += pgcnt) {
2187                                 sz = MIN(pgsz, ptob(npages - pidx));
2188                                 hat_memload_array(sptseg->s_as->a_hat,
2189                                     a, sz, &ppa[pidx],
2190                                     sptd->spt_prot, HAT_LOAD_SHARE);
2191                         }
2192 
2193                         /*
2194                          * And now drop the SE_SHARED lock(s).
2195                          */
2196                         for (i = 0; i < npages; i++)
2197                                 page_unlock(ppa[i]);
2198                 }
2199                 AS_LOCK_EXIT(sptseg->s_as);
2200 
2201                 kmem_free(ppa, sizeof (page_t *) * npages);
2202                 return (0);
2203         case F_SOFTUNLOCK:
2204 
2205                 /*
2206                  * This is a bit ugly, we pass in the real seg pointer,
2207                  * but the sptseg_addr is the virtual address within the
2208                  * dummy seg.
2209                  */
2210                 segspt_softunlock(seg, sptseg_addr, ptob(npages), rw);
2211                 return (0);
2212 
2213         case F_PROT:
2214 
2215                 /*
2216                  * This takes care of the unusual case where a user
2217                  * allocates a stack in shared memory and a register
2218                  * window overflow is written to that stack page before
2219                  * it is otherwise modified.
2220                  *
2221                  * We can get away with this because ISM segments are
2222                  * always rw. Other than this unusual case, there
2223                  * should be no instances of protection violations.
2224                  */
2225                 return (0);
2226 
2227         default:
2228 #ifdef DEBUG
2229                 cmn_err(CE_WARN, "segspt_shmfault default type?");
2230 #endif
2231                 return (FC_NOMAP);
2232         }
2233 }
2234 
2235 /*ARGSUSED*/
2236 static faultcode_t
2237 segspt_shmfaulta(struct seg *seg, caddr_t addr)
2238 {
2239         return (0);
2240 }
2241 
2242 /*ARGSUSED*/
2243 static int
2244 segspt_shmkluster(struct seg *seg, caddr_t addr, ssize_t delta)
2245 {
2246         return (0);
2247 }
2248 
2249 /*ARGSUSED*/
2250 static size_t
2251 segspt_shmswapout(struct seg *seg)
2252 {
2253         return (0);
2254 }
2255 
2256 /*
2257  * duplicate the shared page tables
2258  */
2259 int
2260 segspt_shmdup(struct seg *seg, struct seg *newseg)
2261 {
2262         struct shm_data         *shmd = (struct shm_data *)seg->s_data;
2263         struct anon_map         *amp = shmd->shm_amp;
2264         struct shm_data         *shmd_new;
2265         struct seg              *spt_seg = shmd->shm_sptseg;
2266         struct spt_data         *sptd = spt_seg->s_data;
2267         int                     error = 0;
2268 
2269         ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as));
2270 
2271         shmd_new = kmem_zalloc((sizeof (*shmd_new)), KM_SLEEP);
2272         newseg->s_data = (void *)shmd_new;
2273         shmd_new->shm_sptas = shmd->shm_sptas;
2274         shmd_new->shm_amp = amp;
2275         shmd_new->shm_sptseg = shmd->shm_sptseg;
2276         newseg->s_ops = &segspt_shmops;
2277         newseg->s_szc = seg->s_szc;
2278         ASSERT(seg->s_szc == shmd->shm_sptseg->s_szc);
2279 
2280         ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
2281         amp->refcnt++;
2282         ANON_LOCK_EXIT(&amp->a_rwlock);
2283 
2284         if (sptd->spt_flags & SHM_PAGEABLE) {
2285                 shmd_new->shm_vpage = kmem_zalloc(btopr(amp->size), KM_SLEEP);
2286                 shmd_new->shm_lckpgs = 0;
2287                 if (hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
2288                         if ((error = hat_share(newseg->s_as->a_hat,
2289                             newseg->s_base, shmd->shm_sptas->a_hat, SEGSPTADDR,
2290                             seg->s_size, seg->s_szc)) != 0) {
2291                                 kmem_free(shmd_new->shm_vpage,
2292                                     btopr(amp->size));
2293                         }
2294                 }
2295                 return (error);
2296         } else {
2297                 return (hat_share(newseg->s_as->a_hat, newseg->s_base,
2298                     shmd->shm_sptas->a_hat, SEGSPTADDR, seg->s_size,
2299                     seg->s_szc));
2300 
2301         }
2302 }
2303 
2304 /*ARGSUSED*/
2305 int
2306 segspt_shmcheckprot(struct seg *seg, caddr_t addr, size_t size, uint_t prot)
2307 {
2308         struct shm_data *shmd = (struct shm_data *)seg->s_data;
2309         struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2310 
2311         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
2312 
2313         /*
2314          * ISM segment is always rw.
2315          */
2316         return (((sptd->spt_prot & prot) != prot) ? EACCES : 0);
2317 }
2318 
2319 /*
2320  * Return an array of locked large pages, for empty slots allocate
2321  * private zero-filled anon pages.
2322  */
2323 static int
2324 spt_anon_getpages(
2325         struct seg *sptseg,
2326         caddr_t sptaddr,
2327         size_t len,
2328         page_t *ppa[])
2329 {
2330         struct  spt_data *sptd = sptseg->s_data;
2331         struct  anon_map *amp = sptd->spt_amp;
2332         enum    seg_rw rw = sptd->spt_prot;
2333         uint_t  szc = sptseg->s_szc;
2334         size_t  pg_sz, share_sz = page_get_pagesize(szc);
2335         pgcnt_t lp_npgs;
2336         caddr_t lp_addr, e_sptaddr;
2337         uint_t  vpprot, ppa_szc = 0;
2338         struct  vpage *vpage = NULL;
2339         ulong_t j, ppa_idx;
2340         int     err, ierr = 0;
2341         pgcnt_t an_idx;
2342         anon_sync_obj_t cookie;
2343         int anon_locked = 0;
2344         pgcnt_t amp_pgs;
2345 
2346 
2347         ASSERT(IS_P2ALIGNED(sptaddr, share_sz) && IS_P2ALIGNED(len, share_sz));
2348         ASSERT(len != 0);
2349 
2350         pg_sz = share_sz;
2351         lp_npgs = btop(pg_sz);
2352         lp_addr = sptaddr;
2353         e_sptaddr = sptaddr + len;
2354         an_idx = seg_page(sptseg, sptaddr);
2355         ppa_idx = 0;
2356 
2357         ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2358 
2359         amp_pgs = page_get_pagecnt(amp->a_szc);
2360 
2361         /*CONSTCOND*/
2362         while (1) {
2363                 for (; lp_addr < e_sptaddr;
2364                     an_idx += lp_npgs, lp_addr += pg_sz, ppa_idx += lp_npgs) {
2365 
2366                         /*
2367                          * If we're currently locked, and we get to a new
2368                          * page, unlock our current anon chunk.
2369                          */
2370                         if (anon_locked && P2PHASE(an_idx, amp_pgs) == 0) {
2371                                 anon_array_exit(&cookie);
2372                                 anon_locked = 0;
2373                         }
2374                         if (!anon_locked) {
2375                                 anon_array_enter(amp, an_idx, &cookie);
2376                                 anon_locked = 1;
2377                         }
2378                         ppa_szc = (uint_t)-1;
2379                         ierr = anon_map_getpages(amp, an_idx, szc, sptseg,
2380                             lp_addr, sptd->spt_prot, &vpprot, &ppa[ppa_idx],
2381                             &ppa_szc, vpage, rw, 0, segvn_anypgsz, 0, kcred);
2382 
2383                         if (ierr != 0) {
2384                                 if (ierr > 0) {
2385                                         err = FC_MAKE_ERR(ierr);
2386                                         goto lpgs_err;
2387                                 }
2388                                 break;
2389                         }
2390                 }
2391                 if (lp_addr == e_sptaddr) {
2392                         break;
2393                 }
2394                 ASSERT(lp_addr < e_sptaddr);
2395 
2396                 /*
2397                  * ierr == -1 means we failed to allocate a large page.
2398                  * so do a size down operation.
2399                  *
2400                  * ierr == -2 means some other process that privately shares
2401                  * pages with this process has allocated a larger page and we
2402                  * need to retry with larger pages. So do a size up
2403                  * operation. This relies on the fact that large pages are
2404                  * never partially shared i.e. if we share any constituent
2405                  * page of a large page with another process we must share the
2406                  * entire large page. Note this cannot happen for SOFTLOCK
2407                  * case, unless current address (lpaddr) is at the beginning
2408                  * of the next page size boundary because the other process
2409                  * couldn't have relocated locked pages.
2410                  */
2411                 ASSERT(ierr == -1 || ierr == -2);
2412                 if (segvn_anypgsz) {
2413                         ASSERT(ierr == -2 || szc != 0);
2414                         ASSERT(ierr == -1 || szc < sptseg->s_szc);
2415                         szc = (ierr == -1) ? szc - 1 : szc + 1;
2416                 } else {
2417                         /*
2418                          * For faults and segvn_anypgsz == 0
2419                          * we need to be careful not to loop forever
2420                          * if existing page is found with szc other
2421                          * than 0 or seg->s_szc. This could be due
2422                          * to page relocations on behalf of DR or
2423                          * more likely large page creation. For this
2424                          * case simply re-size to existing page's szc
2425                          * if returned by anon_map_getpages().
2426                          */
2427                         if (ppa_szc == (uint_t)-1) {
2428                                 szc = (ierr == -1) ? 0 : sptseg->s_szc;
2429                         } else {
2430                                 ASSERT(ppa_szc <= sptseg->s_szc);
2431                                 ASSERT(ierr == -2 || ppa_szc < szc);
2432                                 ASSERT(ierr == -1 || ppa_szc > szc);
2433                                 szc = ppa_szc;
2434                         }
2435                 }
2436                 pg_sz = page_get_pagesize(szc);
2437                 lp_npgs = btop(pg_sz);
2438                 ASSERT(IS_P2ALIGNED(lp_addr, pg_sz));
2439         }
2440         if (anon_locked) {
2441                 anon_array_exit(&cookie);
2442         }
2443         ANON_LOCK_EXIT(&amp->a_rwlock);
2444         return (0);
2445 
2446 lpgs_err:
2447         if (anon_locked) {
2448                 anon_array_exit(&cookie);
2449         }
2450         ANON_LOCK_EXIT(&amp->a_rwlock);
2451         for (j = 0; j < ppa_idx; j++)
2452                 page_unlock(ppa[j]);
2453         return (err);
2454 }
2455 
2456 /*
2457  * count the number of bytes in a set of spt pages that are currently not
2458  * locked
2459  */
2460 static rctl_qty_t
2461 spt_unlockedbytes(pgcnt_t npages, page_t **ppa)
2462 {
2463         ulong_t i;
2464         rctl_qty_t unlocked = 0;
2465 
2466         for (i = 0; i < npages; i++) {
2467                 if (ppa[i]->p_lckcnt == 0)
2468                         unlocked += PAGESIZE;
2469         }
2470         return (unlocked);
2471 }
2472 
2473 extern  u_longlong_t randtick(void);
2474 /* number of locks to reserve/skip by spt_lockpages() and spt_unlockpages() */
2475 #define NLCK    (NCPU_P2)
2476 /* Random number with a range [0, n-1], n must be power of two */
2477 #define RAND_P2(n)      \
2478         ((((long)curthread >> PTR24_LSB) ^ (long)randtick()) & ((n) - 1))
2479 
2480 int
2481 spt_lockpages(struct seg *seg, pgcnt_t anon_index, pgcnt_t npages,
2482     page_t **ppa, ulong_t *lockmap, size_t pos,
2483     rctl_qty_t *locked)
2484 {
2485         struct  shm_data *shmd = seg->s_data;
2486         struct  spt_data *sptd = shmd->shm_sptseg->s_data;
2487         ulong_t i;
2488         int     kernel;
2489         pgcnt_t nlck = 0;
2490         int     rv = 0;
2491         int     use_reserved = 1;
2492 
2493         /* return the number of bytes actually locked */
2494         *locked = 0;
2495 
2496         /*
2497          * To avoid contention on freemem_lock, availrmem and pages_locked
2498          * global counters are updated only every nlck locked pages instead of
2499          * every time.  Reserve nlck locks up front and deduct from this
2500          * reservation for each page that requires a lock.  When the reservation
2501          * is consumed, reserve again.  nlck is randomized, so the competing
2502          * threads do not fall into a cyclic lock contention pattern. When
2503          * memory is low, the lock ahead is disabled, and instead page_pp_lock()
2504          * is used to lock pages.
2505          */
2506         for (i = 0; i < npages; anon_index++, pos++, i++) {
2507                 if (nlck == 0 && use_reserved == 1) {
2508                         nlck = NLCK + RAND_P2(NLCK);
2509                         /* if fewer loops left, decrease nlck */
2510                         nlck = MIN(nlck, npages - i);
2511                         /*
2512                          * Reserve nlck locks up front and deduct from this
2513                          * reservation for each page that requires a lock.  When
2514                          * the reservation is consumed, reserve again.
2515                          */
2516                         mutex_enter(&freemem_lock);
2517                         if ((availrmem - nlck) < pages_pp_maximum) {
2518                                 /* Do not do advance memory reserves */
2519                                 use_reserved = 0;
2520                         } else {
2521                                 availrmem       -= nlck;
2522                                 pages_locked    += nlck;
2523                         }
2524                         mutex_exit(&freemem_lock);
2525                 }
2526                 if (!(shmd->shm_vpage[anon_index] & DISM_PG_LOCKED)) {
2527                         if (sptd->spt_ppa_lckcnt[anon_index] <
2528                             (ushort_t)DISM_LOCK_MAX) {
2529                                 if (++sptd->spt_ppa_lckcnt[anon_index] ==
2530                                     (ushort_t)DISM_LOCK_MAX) {
2531                                         cmn_err(CE_WARN,
2532                                             "DISM page lock limit "
2533                                             "reached on DISM offset 0x%lx\n",
2534                                             anon_index << PAGESHIFT);
2535                                 }
2536                                 kernel = (sptd->spt_ppa &&
2537                                     sptd->spt_ppa[anon_index]);
2538                                 if (!page_pp_lock(ppa[i], 0, kernel ||
2539                                     use_reserved)) {
2540                                         sptd->spt_ppa_lckcnt[anon_index]--;
2541                                         rv = EAGAIN;
2542                                         break;
2543                                 }
2544                                 /* if this is a newly locked page, count it */
2545                                 if (ppa[i]->p_lckcnt == 1) {
2546                                         if (kernel == 0 && use_reserved == 1)
2547                                                 nlck--;
2548                                         *locked += PAGESIZE;
2549                                 }
2550                                 shmd->shm_lckpgs++;
2551                                 shmd->shm_vpage[anon_index] |= DISM_PG_LOCKED;
2552                                 if (lockmap != NULL)
2553                                         BT_SET(lockmap, pos);
2554                         }
2555                 }
2556         }
2557         /* Return unused lock reservation */
2558         if (nlck != 0 && use_reserved == 1) {
2559                 mutex_enter(&freemem_lock);
2560                 availrmem       += nlck;
2561                 pages_locked    -= nlck;
2562                 mutex_exit(&freemem_lock);
2563         }
2564 
2565         return (rv);
2566 }
2567 
2568 int
2569 spt_unlockpages(struct seg *seg, pgcnt_t anon_index, pgcnt_t npages,
2570     rctl_qty_t *unlocked)
2571 {
2572         struct shm_data *shmd = seg->s_data;
2573         struct spt_data *sptd = shmd->shm_sptseg->s_data;
2574         struct anon_map *amp = sptd->spt_amp;
2575         struct anon     *ap;
2576         struct vnode    *vp;
2577         u_offset_t      off;
2578         struct page     *pp;
2579         int             kernel;
2580         anon_sync_obj_t cookie;
2581         ulong_t         i;
2582         pgcnt_t         nlck = 0;
2583         pgcnt_t         nlck_limit = NLCK;
2584 
2585         ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2586         for (i = 0; i < npages; i++, anon_index++) {
2587                 if (shmd->shm_vpage[anon_index] & DISM_PG_LOCKED) {
2588                         anon_array_enter(amp, anon_index, &cookie);
2589                         ap = anon_get_ptr(amp->ahp, anon_index);
2590                         ASSERT(ap);
2591 
2592                         swap_xlate(ap, &vp, &off);
2593                         anon_array_exit(&cookie);
2594                         pp = page_lookup(vp, off, SE_SHARED);
2595                         ASSERT(pp);
2596                         /*
2597                          * availrmem is decremented only for pages which are not
2598                          * in seg pcache, for pages in seg pcache availrmem was
2599                          * decremented in _dismpagelock()
2600                          */
2601                         kernel = (sptd->spt_ppa && sptd->spt_ppa[anon_index]);
2602                         ASSERT(pp->p_lckcnt > 0);
2603 
2604                         /*
2605                          * lock page but do not change availrmem, we do it
2606                          * ourselves every nlck loops.
2607                          */
2608                         page_pp_unlock(pp, 0, 1);
2609                         if (pp->p_lckcnt == 0) {
2610                                 if (kernel == 0)
2611                                         nlck++;
2612                                 *unlocked += PAGESIZE;
2613                         }
2614                         page_unlock(pp);
2615                         shmd->shm_vpage[anon_index] &= ~DISM_PG_LOCKED;
2616                         sptd->spt_ppa_lckcnt[anon_index]--;
2617                         shmd->shm_lckpgs--;
2618                 }
2619 
2620                 /*
2621                  * To reduce freemem_lock contention, do not update availrmem
2622                  * until at least NLCK pages have been unlocked.
2623                  * 1. No need to update if nlck is zero
2624                  * 2. Always update if the last iteration
2625                  */
2626                 if (nlck > 0 && (nlck == nlck_limit || i == npages - 1)) {
2627                         mutex_enter(&freemem_lock);
2628                         availrmem       += nlck;
2629                         pages_locked    -= nlck;
2630                         mutex_exit(&freemem_lock);
2631                         nlck = 0;
2632                         nlck_limit = NLCK + RAND_P2(NLCK);
2633                 }
2634         }
2635         ANON_LOCK_EXIT(&amp->a_rwlock);
2636 
2637         return (0);
2638 }
2639 
2640 /*ARGSUSED*/
2641 static int
2642 segspt_shmlockop(struct seg *seg, caddr_t addr, size_t len,
2643     int attr, int op, ulong_t *lockmap, size_t pos)
2644 {
2645         struct shm_data *shmd = seg->s_data;
2646         struct seg      *sptseg = shmd->shm_sptseg;
2647         struct spt_data *sptd = sptseg->s_data;
2648         struct kshmid   *sp = sptd->spt_amp->a_sp;
2649         pgcnt_t         npages, a_npages;
2650         page_t          **ppa;
2651         pgcnt_t         an_idx, a_an_idx, ppa_idx;
2652         caddr_t         spt_addr, a_addr;       /* spt and aligned address */
2653         size_t          a_len;                  /* aligned len */
2654         size_t          share_sz;
2655         ulong_t         i;
2656         int             sts = 0;
2657         rctl_qty_t      unlocked = 0;
2658         rctl_qty_t      locked = 0;
2659         struct proc     *p = curproc;
2660         kproject_t      *proj;
2661 
2662         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
2663         ASSERT(sp != NULL);
2664 
2665         if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
2666                 return (0);
2667         }
2668 
2669         addr = (caddr_t)((uintptr_t)addr & (uintptr_t)PAGEMASK);
2670         an_idx = seg_page(seg, addr);
2671         npages = btopr(len);
2672 
2673         if (an_idx + npages > btopr(shmd->shm_amp->size)) {
2674                 return (ENOMEM);
2675         }
2676 
2677         /*
2678          * A shm's project never changes, so no lock needed.
2679          * The shm has a hold on the project, so it will not go away.
2680          * Since we have a mapping to shm within this zone, we know
2681          * that the zone will not go away.
2682          */
2683         proj = sp->shm_perm.ipc_proj;
2684 
2685         if (op == MC_LOCK) {
2686 
2687                 /*
2688                  * Need to align addr and size request if they are not
2689                  * aligned so we can always allocate large page(s) however
2690                  * we only lock what was requested in initial request.
2691                  */
2692                 share_sz = page_get_pagesize(sptseg->s_szc);
2693                 a_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), share_sz);
2694                 a_len = P2ROUNDUP((uintptr_t)(((addr + len) - a_addr)),
2695                     share_sz);
2696                 a_npages = btop(a_len);
2697                 a_an_idx = seg_page(seg, a_addr);
2698                 spt_addr = sptseg->s_base + ptob(a_an_idx);
2699                 ppa_idx = an_idx - a_an_idx;
2700 
2701                 if ((ppa = kmem_zalloc(((sizeof (page_t *)) * a_npages),
2702                     KM_NOSLEEP)) == NULL) {
2703                         return (ENOMEM);
2704                 }
2705 
2706                 /*
2707                  * Don't cache any new pages for IO and
2708                  * flush any cached pages.
2709                  */
2710                 mutex_enter(&sptd->spt_lock);
2711                 if (sptd->spt_ppa != NULL)
2712                         sptd->spt_flags |= DISM_PPA_CHANGED;
2713 
2714                 sts = spt_anon_getpages(sptseg, spt_addr, a_len, ppa);
2715                 if (sts != 0) {
2716                         mutex_exit(&sptd->spt_lock);
2717                         kmem_free(ppa, ((sizeof (page_t *)) * a_npages));
2718                         return (sts);
2719                 }
2720 
2721                 mutex_enter(&sp->shm_mlock);
2722                 /* enforce locked memory rctl */
2723                 unlocked = spt_unlockedbytes(npages, &ppa[ppa_idx]);
2724 
2725                 mutex_enter(&p->p_lock);
2726                 if (rctl_incr_locked_mem(p, proj, unlocked, 0)) {
2727                         mutex_exit(&p->p_lock);
2728                         sts = EAGAIN;
2729                 } else {
2730                         mutex_exit(&p->p_lock);
2731                         sts = spt_lockpages(seg, an_idx, npages,
2732                             &ppa[ppa_idx], lockmap, pos, &locked);
2733 
2734                         /*
2735                          * correct locked count if not all pages could be
2736                          * locked
2737                          */
2738                         if ((unlocked - locked) > 0) {
2739                                 rctl_decr_locked_mem(NULL, proj,
2740                                     (unlocked - locked), 0);
2741                         }
2742                 }
2743                 /*
2744                  * unlock pages
2745                  */
2746                 for (i = 0; i < a_npages; i++)
2747                         page_unlock(ppa[i]);
2748                 if (sptd->spt_ppa != NULL)
2749                         sptd->spt_flags |= DISM_PPA_CHANGED;
2750                 mutex_exit(&sp->shm_mlock);
2751                 mutex_exit(&sptd->spt_lock);
2752 
2753                 kmem_free(ppa, ((sizeof (page_t *)) * a_npages));
2754 
2755         } else if (op == MC_UNLOCK) { /* unlock */
2756                 page_t          **ppa;
2757 
2758                 mutex_enter(&sptd->spt_lock);
2759                 if (shmd->shm_lckpgs == 0) {
2760                         mutex_exit(&sptd->spt_lock);
2761                         return (0);
2762                 }
2763                 /*
2764                  * Don't cache new IO pages.
2765                  */
2766                 if (sptd->spt_ppa != NULL)
2767                         sptd->spt_flags |= DISM_PPA_CHANGED;
2768 
2769                 mutex_enter(&sp->shm_mlock);
2770                 sts = spt_unlockpages(seg, an_idx, npages, &unlocked);
2771                 if ((ppa = sptd->spt_ppa) != NULL)
2772                         sptd->spt_flags |= DISM_PPA_CHANGED;
2773                 mutex_exit(&sptd->spt_lock);
2774 
2775                 rctl_decr_locked_mem(NULL, proj, unlocked, 0);
2776                 mutex_exit(&sp->shm_mlock);
2777 
2778                 if (ppa != NULL)
2779                         seg_ppurge_wiredpp(ppa);
2780         }
2781         return (sts);
2782 }
2783 
2784 /*ARGSUSED*/
2785 int
2786 segspt_shmgetprot(struct seg *seg, caddr_t addr, size_t len, uint_t *protv)
2787 {
2788         struct shm_data *shmd = (struct shm_data *)seg->s_data;
2789         struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2790         spgcnt_t pgno = seg_page(seg, addr+len) - seg_page(seg, addr) + 1;
2791 
2792         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
2793 
2794         /*
2795          * ISM segment is always rw.
2796          */
2797         while (--pgno >= 0)
2798                 *protv++ = sptd->spt_prot;
2799         return (0);
2800 }
2801 
2802 /*ARGSUSED*/
2803 u_offset_t
2804 segspt_shmgetoffset(struct seg *seg, caddr_t addr)
2805 {
2806         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
2807 
2808         /* Offset does not matter in ISM memory */
2809 
2810         return ((u_offset_t)0);
2811 }
2812 
2813 /* ARGSUSED */
2814 int
2815 segspt_shmgettype(struct seg *seg, caddr_t addr)
2816 {
2817         struct shm_data *shmd = (struct shm_data *)seg->s_data;
2818         struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2819 
2820         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
2821 
2822         /*
2823          * The shared memory mapping is always MAP_SHARED, SWAP is only
2824          * reserved for DISM
2825          */
2826         return (MAP_SHARED |
2827             ((sptd->spt_flags & SHM_PAGEABLE) ? 0 : MAP_NORESERVE));
2828 }
2829 
2830 /*ARGSUSED*/
2831 int
2832 segspt_shmgetvp(struct seg *seg, caddr_t addr, struct vnode **vpp)
2833 {
2834         struct shm_data *shmd = (struct shm_data *)seg->s_data;
2835         struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2836 
2837         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
2838 
2839         *vpp = sptd->spt_vp;
2840         return (0);
2841 }
2842 
2843 /*
2844  * We need to wait for pending IO to complete to a DISM segment in order for
2845  * pages to get kicked out of the seg_pcache.  120 seconds should be more
2846  * than enough time to wait.
2847  */
2848 static clock_t spt_pcache_wait = 120;
2849 
2850 /*ARGSUSED*/
2851 static int
2852 segspt_shmadvise(struct seg *seg, caddr_t addr, size_t len, uint_t behav)
2853 {
2854         struct shm_data *shmd = (struct shm_data *)seg->s_data;
2855         struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2856         struct anon_map *amp;
2857         pgcnt_t pg_idx;
2858         ushort_t gen;
2859         clock_t end_lbolt;
2860         int writer;
2861         page_t **ppa;
2862 
2863         ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
2864 
2865         if (behav == MADV_FREE || behav == MADV_PURGE) {
2866                 if ((sptd->spt_flags & SHM_PAGEABLE) == 0)
2867                         return (0);
2868 
2869                 amp = sptd->spt_amp;
2870                 pg_idx = seg_page(seg, addr);
2871 
2872                 mutex_enter(&sptd->spt_lock);
2873                 if ((ppa = sptd->spt_ppa) == NULL) {
2874                         mutex_exit(&sptd->spt_lock);
2875                         ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2876                         (void) anon_disclaim(amp, pg_idx, len, behav, NULL);
2877                         ANON_LOCK_EXIT(&amp->a_rwlock);
2878                         return (0);
2879                 }
2880 
2881                 sptd->spt_flags |= DISM_PPA_CHANGED;
2882                 gen = sptd->spt_gen;
2883 
2884                 mutex_exit(&sptd->spt_lock);
2885 
2886                 /*
2887                  * Purge all DISM cached pages
2888                  */
2889                 seg_ppurge_wiredpp(ppa);
2890 
2891                 /*
2892                  * Drop the AS_LOCK so that other threads can grab it
2893                  * in the as_pageunlock path and hopefully get the segment
2894                  * kicked out of the seg_pcache.  We bump the shm_softlockcnt
2895                  * to keep this segment resident.
2896                  */
2897                 writer = AS_WRITE_HELD(seg->s_as);
2898                 atomic_inc_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
2899                 AS_LOCK_EXIT(seg->s_as);
2900 
2901                 mutex_enter(&sptd->spt_lock);
2902 
2903                 end_lbolt = ddi_get_lbolt() + (hz * spt_pcache_wait);
2904 
2905                 /*
2906                  * Try to wait for pages to get kicked out of the seg_pcache.
2907                  */
2908                 while (sptd->spt_gen == gen &&
2909                     (sptd->spt_flags & DISM_PPA_CHANGED) &&
2910                     ddi_get_lbolt() < end_lbolt) {
2911                         if (!cv_timedwait_sig(&sptd->spt_cv,
2912                             &sptd->spt_lock, end_lbolt)) {
2913                                 break;
2914                         }
2915                 }
2916 
2917                 mutex_exit(&sptd->spt_lock);
2918 
2919                 /* Regrab the AS_LOCK and release our hold on the segment */
2920                 AS_LOCK_ENTER(seg->s_as, writer ? RW_WRITER : RW_READER);
2921                 atomic_dec_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
2922                 if (shmd->shm_softlockcnt <= 0) {
2923                         if (AS_ISUNMAPWAIT(seg->s_as)) {
2924                                 mutex_enter(&seg->s_as->a_contents);
2925                                 if (AS_ISUNMAPWAIT(seg->s_as)) {
2926                                         AS_CLRUNMAPWAIT(seg->s_as);
2927                                         cv_broadcast(&seg->s_as->a_cv);
2928                                 }
2929                                 mutex_exit(&seg->s_as->a_contents);
2930                         }
2931                 }
2932 
2933                 ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2934                 (void) anon_disclaim(amp, pg_idx, len, behav, NULL);
2935                 ANON_LOCK_EXIT(&amp->a_rwlock);
2936         } else if (lgrp_optimizations() && (behav == MADV_ACCESS_LWP ||
2937             behav == MADV_ACCESS_MANY || behav == MADV_ACCESS_DEFAULT)) {
2938                 int                     already_set;
2939                 ulong_t                 anon_index;
2940                 lgrp_mem_policy_t       policy;
2941                 caddr_t                 shm_addr;
2942                 size_t                  share_size;
2943                 size_t                  size;
2944                 struct seg              *sptseg = shmd->shm_sptseg;
2945                 caddr_t                 sptseg_addr;
2946 
2947                 /*
2948                  * Align address and length to page size of underlying segment
2949                  */
2950                 share_size = page_get_pagesize(shmd->shm_sptseg->s_szc);
2951                 shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), share_size);
2952                 size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)),
2953                     share_size);
2954 
2955                 amp = shmd->shm_amp;
2956                 anon_index = seg_page(seg, shm_addr);
2957 
2958                 /*
2959                  * And now we may have to adjust size downward if we have
2960                  * exceeded the realsize of the segment or initial anon
2961                  * allocations.
2962                  */
2963                 sptseg_addr = sptseg->s_base + ptob(anon_index);
2964                 if ((sptseg_addr + size) >
2965                     (sptseg->s_base + sptd->spt_realsize))
2966                         size = (sptseg->s_base + sptd->spt_realsize) -
2967                             sptseg_addr;
2968 
2969                 /*
2970                  * Set memory allocation policy for this segment
2971                  */
2972                 policy = lgrp_madv_to_policy(behav, len, MAP_SHARED);
2973                 already_set = lgrp_shm_policy_set(policy, amp, anon_index,
2974                     NULL, 0, len);
2975 
2976                 /*
2977                  * If random memory allocation policy set already,
2978                  * don't bother reapplying it.
2979                  */
2980                 if (already_set && !LGRP_MEM_POLICY_REAPPLICABLE(policy))
2981                         return (0);
2982 
2983                 /*
2984                  * Mark any existing pages in the given range for
2985                  * migration, flushing the I/O page cache, and using
2986                  * underlying segment to calculate anon index and get
2987                  * anonmap and vnode pointer from
2988                  */
2989                 if (shmd->shm_softlockcnt > 0)
2990                         segspt_purge(seg);
2991 
2992                 page_mark_migrate(seg, shm_addr, size, amp, 0, NULL, 0, 0);
2993         }
2994 
2995         return (0);
2996 }
2997 
2998 /*ARGSUSED*/
2999 void
3000 segspt_shmdump(struct seg *seg)
3001 {
3002         /* no-op for ISM segment */
3003 }
3004 
3005 /*ARGSUSED*/
3006 static faultcode_t
3007 segspt_shmsetpgsz(struct seg *seg, caddr_t addr, size_t len, uint_t szc)
3008 {
3009         return (ENOTSUP);
3010 }
3011 
3012 /*
3013  * get a memory ID for an addr in a given segment
3014  */
3015 static int
3016 segspt_shmgetmemid(struct seg *seg, caddr_t addr, memid_t *memidp)
3017 {
3018         struct shm_data *shmd = (struct shm_data *)seg->s_data;
3019         struct anon     *ap;
3020         size_t          anon_index;
3021         struct anon_map *amp = shmd->shm_amp;
3022         struct spt_data *sptd = shmd->shm_sptseg->s_data;
3023         struct seg      *sptseg = shmd->shm_sptseg;
3024         anon_sync_obj_t cookie;
3025 
3026         anon_index = seg_page(seg, addr);
3027 
3028         if (addr > (seg->s_base + sptd->spt_realsize)) {
3029                 return (EFAULT);
3030         }
3031 
3032         ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
3033         anon_array_enter(amp, anon_index, &cookie);
3034         ap = anon_get_ptr(amp->ahp, anon_index);
3035         if (ap == NULL) {
3036                 struct page *pp;
3037                 caddr_t spt_addr = sptseg->s_base + ptob(anon_index);
3038 
3039                 pp = anon_zero(sptseg, spt_addr, &ap, kcred);
3040                 if (pp == NULL) {
3041                         anon_array_exit(&cookie);
3042                         ANON_LOCK_EXIT(&amp->a_rwlock);
3043                         return (ENOMEM);
3044                 }
3045                 (void) anon_set_ptr(amp->ahp, anon_index, ap, ANON_SLEEP);
3046                 page_unlock(pp);
3047         }
3048         anon_array_exit(&cookie);
3049         ANON_LOCK_EXIT(&amp->a_rwlock);
3050         memidp->val[0] = (uintptr_t)ap;
3051         memidp->val[1] = (uintptr_t)addr & PAGEOFFSET;
3052         return (0);
3053 }
3054 
3055 /*
3056  * Get memory allocation policy info for specified address in given segment
3057  */
3058 static lgrp_mem_policy_info_t *
3059 segspt_shmgetpolicy(struct seg *seg, caddr_t addr)
3060 {
3061         struct anon_map         *amp;
3062         ulong_t                 anon_index;
3063         lgrp_mem_policy_info_t  *policy_info;
3064         struct shm_data         *shm_data;
3065 
3066         ASSERT(seg != NULL);
3067 
3068         /*
3069          * Get anon_map from segshm
3070          *
3071          * Assume that no lock needs to be held on anon_map, since
3072          * it should be protected by its reference count which must be
3073          * nonzero for an existing segment
3074          * Need to grab readers lock on policy tree though
3075          */
3076         shm_data = (struct shm_data *)seg->s_data;
3077         if (shm_data == NULL)
3078                 return (NULL);
3079         amp = shm_data->shm_amp;
3080         ASSERT(amp->refcnt != 0);
3081 
3082         /*
3083          * Get policy info
3084          *
3085          * Assume starting anon index of 0
3086          */
3087         anon_index = seg_page(seg, addr);
3088         policy_info = lgrp_shm_policy_get(amp, anon_index, NULL, 0);
3089 
3090         return (policy_info);
3091 }
3092 
3093 /*ARGSUSED*/
3094 static int
3095 segspt_shmcapable(struct seg *seg, segcapability_t capability)
3096 {
3097         return (0);
3098 }