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 /*
23 * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26 #include <sys/types.h>
27 #include <sys/sysmacros.h>
28 #include <sys/kmem.h>
29 #include <sys/atomic.h>
30 #include <sys/bitmap.h>
31 #include <sys/machparam.h>
32 #include <sys/machsystm.h>
33 #include <sys/mman.h>
34 #include <sys/systm.h>
35 #include <sys/cpuvar.h>
36 #include <sys/thread.h>
37 #include <sys/proc.h>
38 #include <sys/cpu.h>
39 #include <sys/kmem.h>
40 #include <sys/disp.h>
41 #include <sys/vmem.h>
42 #include <sys/vmsystm.h>
43 #include <sys/promif.h>
44 #include <sys/var.h>
45 #include <sys/x86_archext.h>
46 #include <sys/archsystm.h>
47 #include <sys/bootconf.h>
48 #include <sys/dumphdr.h>
49 #include <vm/seg_kmem.h>
50 #include <vm/seg_kpm.h>
51 #include <vm/hat.h>
52 #include <vm/hat_i86.h>
53 #include <sys/cmn_err.h>
54 #include <sys/panic.h>
55
56 #ifdef __xpv
57 #include <sys/hypervisor.h>
58 #include <sys/xpv_panic.h>
59 #endif
60
61 #include <sys/bootinfo.h>
62 #include <vm/kboot_mmu.h>
63
64 static void x86pte_zero(htable_t *dest, uint_t entry, uint_t count);
65
66 kmem_cache_t *htable_cache;
67
68 /*
69 * The variable htable_reserve_amount, rather than HTABLE_RESERVE_AMOUNT,
70 * is used in order to facilitate testing of the htable_steal() code.
71 * By resetting htable_reserve_amount to a lower value, we can force
72 * stealing to occur. The reserve amount is a guess to get us through boot.
73 */
74 #define HTABLE_RESERVE_AMOUNT (200)
75 uint_t htable_reserve_amount = HTABLE_RESERVE_AMOUNT;
76 kmutex_t htable_reserve_mutex;
77 uint_t htable_reserve_cnt;
78 htable_t *htable_reserve_pool;
79
80 /*
81 * Used to hand test htable_steal().
82 */
83 #ifdef DEBUG
84 ulong_t force_steal = 0;
85 ulong_t ptable_cnt = 0;
86 #endif
87
88 /*
89 * This variable is so that we can tune this via /etc/system
90 * Any value works, but a power of two <= mmu.ptes_per_table is best.
91 */
92 uint_t htable_steal_passes = 8;
93
94 /*
95 * mutex stuff for access to htable hash
96 */
97 #define NUM_HTABLE_MUTEX 128
98 kmutex_t htable_mutex[NUM_HTABLE_MUTEX];
99 #define HTABLE_MUTEX_HASH(h) ((h) & (NUM_HTABLE_MUTEX - 1))
100
101 #define HTABLE_ENTER(h) mutex_enter(&htable_mutex[HTABLE_MUTEX_HASH(h)]);
102 #define HTABLE_EXIT(h) mutex_exit(&htable_mutex[HTABLE_MUTEX_HASH(h)]);
103
104 /*
105 * forward declarations
106 */
107 static void link_ptp(htable_t *higher, htable_t *new, uintptr_t vaddr);
108 static void unlink_ptp(htable_t *higher, htable_t *old, uintptr_t vaddr);
109 static void htable_free(htable_t *ht);
110 static x86pte_t *x86pte_access_pagetable(htable_t *ht, uint_t index);
111 static void x86pte_release_pagetable(htable_t *ht);
112 static x86pte_t x86pte_cas(htable_t *ht, uint_t entry, x86pte_t old,
113 x86pte_t new);
114
115 /*
116 * A counter to track if we are stealing or reaping htables. When non-zero
117 * htable_free() will directly free htables (either to the reserve or kmem)
118 * instead of putting them in a hat's htable cache.
119 */
120 uint32_t htable_dont_cache = 0;
121
122 /*
123 * Track the number of active pagetables, so we can know how many to reap
124 */
125 static uint32_t active_ptables = 0;
126
127 #ifdef __xpv
128 /*
129 * Deal with hypervisor complications.
130 */
131 void
132 xen_flush_va(caddr_t va)
133 {
134 struct mmuext_op t;
135 uint_t count;
136
137 if (IN_XPV_PANIC()) {
138 mmu_tlbflush_entry((caddr_t)va);
139 } else {
140 t.cmd = MMUEXT_INVLPG_LOCAL;
141 t.arg1.linear_addr = (uintptr_t)va;
142 if (HYPERVISOR_mmuext_op(&t, 1, &count, DOMID_SELF) < 0)
143 panic("HYPERVISOR_mmuext_op() failed");
144 ASSERT(count == 1);
145 }
146 }
147
148 void
149 xen_gflush_va(caddr_t va, cpuset_t cpus)
150 {
151 struct mmuext_op t;
152 uint_t count;
153
154 if (IN_XPV_PANIC()) {
155 mmu_tlbflush_entry((caddr_t)va);
156 return;
157 }
158
159 t.cmd = MMUEXT_INVLPG_MULTI;
160 t.arg1.linear_addr = (uintptr_t)va;
161 /*LINTED: constant in conditional context*/
162 set_xen_guest_handle(t.arg2.vcpumask, &cpus);
163 if (HYPERVISOR_mmuext_op(&t, 1, &count, DOMID_SELF) < 0)
164 panic("HYPERVISOR_mmuext_op() failed");
165 ASSERT(count == 1);
166 }
167
168 void
169 xen_flush_tlb()
170 {
171 struct mmuext_op t;
172 uint_t count;
173
174 if (IN_XPV_PANIC()) {
175 xpv_panic_reload_cr3();
176 } else {
177 t.cmd = MMUEXT_TLB_FLUSH_LOCAL;
178 if (HYPERVISOR_mmuext_op(&t, 1, &count, DOMID_SELF) < 0)
179 panic("HYPERVISOR_mmuext_op() failed");
180 ASSERT(count == 1);
181 }
182 }
183
184 void
185 xen_gflush_tlb(cpuset_t cpus)
186 {
187 struct mmuext_op t;
188 uint_t count;
189
190 ASSERT(!IN_XPV_PANIC());
191 t.cmd = MMUEXT_TLB_FLUSH_MULTI;
192 /*LINTED: constant in conditional context*/
193 set_xen_guest_handle(t.arg2.vcpumask, &cpus);
194 if (HYPERVISOR_mmuext_op(&t, 1, &count, DOMID_SELF) < 0)
195 panic("HYPERVISOR_mmuext_op() failed");
196 ASSERT(count == 1);
197 }
198
199 /*
200 * Install/Adjust a kpm mapping under the hypervisor.
201 * Value of "how" should be:
202 * PT_WRITABLE | PT_VALID - regular kpm mapping
203 * PT_VALID - make mapping read-only
204 * 0 - remove mapping
205 *
206 * returns 0 on success. non-zero for failure.
207 */
208 int
209 xen_kpm_page(pfn_t pfn, uint_t how)
210 {
211 paddr_t pa = mmu_ptob((paddr_t)pfn);
212 x86pte_t pte = PT_NOCONSIST | PT_REF | PT_MOD;
213
214 if (kpm_vbase == NULL)
215 return (0);
216
217 if (how)
218 pte |= pa_to_ma(pa) | how;
219 else
220 pte = 0;
221 return (HYPERVISOR_update_va_mapping((uintptr_t)kpm_vbase + pa,
222 pte, UVMF_INVLPG | UVMF_ALL));
223 }
224
225 void
226 xen_pin(pfn_t pfn, level_t lvl)
227 {
228 struct mmuext_op t;
229 uint_t count;
230
231 t.cmd = MMUEXT_PIN_L1_TABLE + lvl;
232 t.arg1.mfn = pfn_to_mfn(pfn);
233 if (HYPERVISOR_mmuext_op(&t, 1, &count, DOMID_SELF) < 0)
234 panic("HYPERVISOR_mmuext_op() failed");
235 ASSERT(count == 1);
236 }
237
238 void
239 xen_unpin(pfn_t pfn)
240 {
241 struct mmuext_op t;
242 uint_t count;
243
244 t.cmd = MMUEXT_UNPIN_TABLE;
245 t.arg1.mfn = pfn_to_mfn(pfn);
246 if (HYPERVISOR_mmuext_op(&t, 1, &count, DOMID_SELF) < 0)
247 panic("HYPERVISOR_mmuext_op() failed");
248 ASSERT(count == 1);
249 }
250
251 static void
252 xen_map(uint64_t pte, caddr_t va)
253 {
254 if (HYPERVISOR_update_va_mapping((uintptr_t)va, pte,
255 UVMF_INVLPG | UVMF_LOCAL))
256 panic("HYPERVISOR_update_va_mapping() failed");
257 }
258 #endif /* __xpv */
259
260 /*
261 * Allocate a memory page for a hardware page table.
262 *
263 * A wrapper around page_get_physical(), with some extra checks.
264 */
265 static pfn_t
266 ptable_alloc(uintptr_t seed)
267 {
268 pfn_t pfn;
269 page_t *pp;
270
271 pfn = PFN_INVALID;
272
273 /*
274 * The first check is to see if there is memory in the system. If we
275 * drop to throttlefree, then fail the ptable_alloc() and let the
276 * stealing code kick in. Note that we have to do this test here,
277 * since the test in page_create_throttle() would let the NOSLEEP
278 * allocation go through and deplete the page reserves.
279 *
280 * The !NOMEMWAIT() lets pageout, fsflush, etc. skip this check.
281 */
282 if (!NOMEMWAIT() && freemem <= throttlefree + 1)
283 return (PFN_INVALID);
284
285 #ifdef DEBUG
286 /*
287 * This code makes htable_steal() easier to test. By setting
288 * force_steal we force pagetable allocations to fall
289 * into the stealing code. Roughly 1 in ever "force_steal"
290 * page table allocations will fail.
291 */
292 if (proc_pageout != NULL && force_steal > 1 &&
293 ++ptable_cnt > force_steal) {
294 ptable_cnt = 0;
295 return (PFN_INVALID);
296 }
297 #endif /* DEBUG */
298
299 pp = page_get_physical(seed);
300 if (pp == NULL)
301 return (PFN_INVALID);
302 ASSERT(PAGE_SHARED(pp));
303 pfn = pp->p_pagenum;
304 if (pfn == PFN_INVALID)
305 panic("ptable_alloc(): Invalid PFN!!");
306 atomic_add_32(&active_ptables, 1);
307 HATSTAT_INC(hs_ptable_allocs);
308 return (pfn);
309 }
310
311 /*
312 * Free an htable's associated page table page. See the comments
313 * for ptable_alloc().
314 */
315 static void
316 ptable_free(pfn_t pfn)
317 {
318 page_t *pp = page_numtopp_nolock(pfn);
319
320 /*
321 * need to destroy the page used for the pagetable
322 */
323 ASSERT(pfn != PFN_INVALID);
324 HATSTAT_INC(hs_ptable_frees);
325 atomic_add_32(&active_ptables, -1);
326 if (pp == NULL)
327 panic("ptable_free(): no page for pfn!");
328 ASSERT(PAGE_SHARED(pp));
329 ASSERT(pfn == pp->p_pagenum);
330 ASSERT(!IN_XPV_PANIC());
331
332 /*
333 * Get an exclusive lock, might have to wait for a kmem reader.
334 */
335 if (!page_tryupgrade(pp)) {
336 u_offset_t off = pp->p_offset;
337 page_unlock(pp);
338 pp = page_lookup(&kvp, off, SE_EXCL);
339 if (pp == NULL)
340 panic("page not found");
341 }
342 #ifdef __xpv
343 if (kpm_vbase && xen_kpm_page(pfn, PT_VALID | PT_WRITABLE) < 0)
344 panic("failure making kpm r/w pfn=0x%lx", pfn);
345 #endif
346 page_hashout(pp, NULL);
347 page_free(pp, 1);
348 page_unresv(1);
349 }
350
351 /*
352 * Put one htable on the reserve list.
353 */
354 static void
355 htable_put_reserve(htable_t *ht)
356 {
357 ht->ht_hat = NULL; /* no longer tied to a hat */
358 ASSERT(ht->ht_pfn == PFN_INVALID);
359 HATSTAT_INC(hs_htable_rputs);
360 mutex_enter(&htable_reserve_mutex);
361 ht->ht_next = htable_reserve_pool;
362 htable_reserve_pool = ht;
363 ++htable_reserve_cnt;
364 mutex_exit(&htable_reserve_mutex);
365 }
366
367 /*
368 * Take one htable from the reserve.
369 */
370 static htable_t *
371 htable_get_reserve(void)
372 {
373 htable_t *ht = NULL;
374
375 mutex_enter(&htable_reserve_mutex);
376 if (htable_reserve_cnt != 0) {
377 ht = htable_reserve_pool;
378 ASSERT(ht != NULL);
379 ASSERT(ht->ht_pfn == PFN_INVALID);
380 htable_reserve_pool = ht->ht_next;
381 --htable_reserve_cnt;
382 HATSTAT_INC(hs_htable_rgets);
383 }
384 mutex_exit(&htable_reserve_mutex);
385 return (ht);
386 }
387
388 /*
389 * Allocate initial htables and put them on the reserve list
390 */
391 void
392 htable_initial_reserve(uint_t count)
393 {
394 htable_t *ht;
395
396 count += HTABLE_RESERVE_AMOUNT;
397 while (count > 0) {
398 ht = kmem_cache_alloc(htable_cache, KM_NOSLEEP);
399 ASSERT(ht != NULL);
400
401 ASSERT(use_boot_reserve);
402 ht->ht_pfn = PFN_INVALID;
403 htable_put_reserve(ht);
404 --count;
405 }
406 }
407
408 /*
409 * Readjust the reserves after a thread finishes using them.
410 */
411 void
412 htable_adjust_reserve()
413 {
414 htable_t *ht;
415
416 /*
417 * Free any excess htables in the reserve list
418 */
419 while (htable_reserve_cnt > htable_reserve_amount &&
420 !USE_HAT_RESERVES()) {
421 ht = htable_get_reserve();
422 if (ht == NULL)
423 return;
424 ASSERT(ht->ht_pfn == PFN_INVALID);
425 kmem_cache_free(htable_cache, ht);
426 }
427 }
428
429
430 /*
431 * This routine steals htables from user processes for htable_alloc() or
432 * for htable_reap().
433 */
434 static htable_t *
435 htable_steal(uint_t cnt)
436 {
437 hat_t *hat = kas.a_hat; /* list starts with khat */
438 htable_t *list = NULL;
439 htable_t *ht;
440 htable_t *higher;
441 uint_t h;
442 uint_t h_start;
443 static uint_t h_seed = 0;
444 uint_t e;
445 uintptr_t va;
446 x86pte_t pte;
447 uint_t stolen = 0;
448 uint_t pass;
449 uint_t threshold;
450
451 /*
452 * Limit htable_steal_passes to something reasonable
453 */
454 if (htable_steal_passes == 0)
455 htable_steal_passes = 1;
456 if (htable_steal_passes > mmu.ptes_per_table)
457 htable_steal_passes = mmu.ptes_per_table;
458
459 /*
460 * Loop through all user hats. The 1st pass takes cached htables that
461 * aren't in use. The later passes steal by removing mappings, too.
462 */
463 atomic_add_32(&htable_dont_cache, 1);
464 for (pass = 0; pass <= htable_steal_passes && stolen < cnt; ++pass) {
465 threshold = pass * mmu.ptes_per_table / htable_steal_passes;
466 hat = kas.a_hat;
467 for (;;) {
468
469 /*
470 * Clear the victim flag and move to next hat
471 */
472 mutex_enter(&hat_list_lock);
473 if (hat != kas.a_hat) {
474 hat->hat_flags &= ~HAT_VICTIM;
475 cv_broadcast(&hat_list_cv);
476 }
477 hat = hat->hat_next;
478
479 /*
480 * Skip any hat that is already being stolen from.
481 *
482 * We skip SHARED hats, as these are dummy
483 * hats that host ISM shared page tables.
484 *
485 * We also skip if HAT_FREEING because hat_pte_unmap()
486 * won't zero out the PTE's. That would lead to hitting
487 * stale PTEs either here or under hat_unload() when we
488 * steal and unload the same page table in competing
489 * threads.
490 */
491 while (hat != NULL &&
492 (hat->hat_flags &
493 (HAT_VICTIM | HAT_SHARED | HAT_FREEING)) != 0)
494 hat = hat->hat_next;
495
496 if (hat == NULL) {
497 mutex_exit(&hat_list_lock);
498 break;
499 }
500
501 /*
502 * Are we finished?
503 */
504 if (stolen == cnt) {
505 /*
506 * Try to spread the pain of stealing,
507 * move victim HAT to the end of the HAT list.
508 */
509 if (pass >= 1 && cnt == 1 &&
510 kas.a_hat->hat_prev != hat) {
511
512 /* unlink victim hat */
513 if (hat->hat_prev)
514 hat->hat_prev->hat_next =
515 hat->hat_next;
516 else
517 kas.a_hat->hat_next =
518 hat->hat_next;
519 if (hat->hat_next)
520 hat->hat_next->hat_prev =
521 hat->hat_prev;
522 else
523 kas.a_hat->hat_prev =
524 hat->hat_prev;
525
526
527 /* relink at end of hat list */
528 hat->hat_next = NULL;
529 hat->hat_prev = kas.a_hat->hat_prev;
530 if (hat->hat_prev)
531 hat->hat_prev->hat_next = hat;
532 else
533 kas.a_hat->hat_next = hat;
534 kas.a_hat->hat_prev = hat;
535
536 }
537
538 mutex_exit(&hat_list_lock);
539 break;
540 }
541
542 /*
543 * Mark the HAT as a stealing victim.
544 */
545 hat->hat_flags |= HAT_VICTIM;
546 mutex_exit(&hat_list_lock);
547
548 /*
549 * Take any htables from the hat's cached "free" list.
550 */
551 hat_enter(hat);
552 while ((ht = hat->hat_ht_cached) != NULL &&
553 stolen < cnt) {
554 hat->hat_ht_cached = ht->ht_next;
555 ht->ht_next = list;
556 list = ht;
557 ++stolen;
558 }
559 hat_exit(hat);
560
561 /*
562 * Don't steal on first pass.
563 */
564 if (pass == 0 || stolen == cnt)
565 continue;
566
567 /*
568 * Search the active htables for one to steal.
569 * Start at a different hash bucket every time to
570 * help spread the pain of stealing.
571 */
572 h = h_start = h_seed++ % hat->hat_num_hash;
573 do {
574 higher = NULL;
575 HTABLE_ENTER(h);
576 for (ht = hat->hat_ht_hash[h]; ht;
577 ht = ht->ht_next) {
578
579 /*
580 * Can we rule out reaping?
581 */
582 if (ht->ht_busy != 0 ||
583 (ht->ht_flags & HTABLE_SHARED_PFN)||
584 ht->ht_level > 0 ||
585 ht->ht_valid_cnt > threshold ||
586 ht->ht_lock_cnt != 0)
587 continue;
588
589 /*
590 * Increment busy so the htable can't
591 * disappear. We drop the htable mutex
592 * to avoid deadlocks with
593 * hat_pageunload() and the hment mutex
594 * while we call hat_pte_unmap()
595 */
596 ++ht->ht_busy;
597 HTABLE_EXIT(h);
598
599 /*
600 * Try stealing.
601 * - unload and invalidate all PTEs
602 */
603 for (e = 0, va = ht->ht_vaddr;
604 e < HTABLE_NUM_PTES(ht) &&
605 ht->ht_valid_cnt > 0 &&
606 ht->ht_busy == 1 &&
607 ht->ht_lock_cnt == 0;
608 ++e, va += MMU_PAGESIZE) {
609 pte = x86pte_get(ht, e);
610 if (!PTE_ISVALID(pte))
611 continue;
612 hat_pte_unmap(ht, e,
613 HAT_UNLOAD, pte, NULL);
614 }
615
616 /*
617 * Reacquire htable lock. If we didn't
618 * remove all mappings in the table,
619 * or another thread added a new mapping
620 * behind us, give up on this table.
621 */
622 HTABLE_ENTER(h);
623 if (ht->ht_busy != 1 ||
624 ht->ht_valid_cnt != 0 ||
625 ht->ht_lock_cnt != 0) {
626 --ht->ht_busy;
627 continue;
628 }
629
630 /*
631 * Steal it and unlink the page table.
632 */
633 higher = ht->ht_parent;
634 unlink_ptp(higher, ht, ht->ht_vaddr);
635
636 /*
637 * remove from the hash list
638 */
639 if (ht->ht_next)
640 ht->ht_next->ht_prev =
641 ht->ht_prev;
642
643 if (ht->ht_prev) {
644 ht->ht_prev->ht_next =
645 ht->ht_next;
646 } else {
647 ASSERT(hat->hat_ht_hash[h] ==
648 ht);
649 hat->hat_ht_hash[h] =
650 ht->ht_next;
651 }
652
653 /*
654 * Break to outer loop to release the
655 * higher (ht_parent) pagetable. This
656 * spreads out the pain caused by
657 * pagefaults.
658 */
659 ht->ht_next = list;
660 list = ht;
661 ++stolen;
662 break;
663 }
664 HTABLE_EXIT(h);
665 if (higher != NULL)
666 htable_release(higher);
667 if (++h == hat->hat_num_hash)
668 h = 0;
669 } while (stolen < cnt && h != h_start);
670 }
671 }
672 atomic_add_32(&htable_dont_cache, -1);
673 return (list);
674 }
675
676 /*
677 * This is invoked from kmem when the system is low on memory. We try
678 * to free hments, htables, and ptables to improve the memory situation.
679 */
680 /*ARGSUSED*/
681 static void
682 htable_reap(void *handle)
683 {
684 uint_t reap_cnt;
685 htable_t *list;
686 htable_t *ht;
687
688 HATSTAT_INC(hs_reap_attempts);
689 if (!can_steal_post_boot)
690 return;
691
692 /*
693 * Try to reap 5% of the page tables bounded by a maximum of
694 * 5% of physmem and a minimum of 10.
695 */
696 reap_cnt = MAX(MIN(physmem / 20, active_ptables / 20), 10);
697
698 /*
699 * Let htable_steal() do the work, we just call htable_free()
700 */
701 XPV_DISALLOW_MIGRATE();
702 list = htable_steal(reap_cnt);
703 XPV_ALLOW_MIGRATE();
704 while ((ht = list) != NULL) {
705 list = ht->ht_next;
706 HATSTAT_INC(hs_reaped);
707 htable_free(ht);
708 }
709
710 /*
711 * Free up excess reserves
712 */
713 htable_adjust_reserve();
714 hment_adjust_reserve();
715 }
716
717 /*
718 * Allocate an htable, stealing one or using the reserve if necessary
719 */
720 static htable_t *
721 htable_alloc(
722 hat_t *hat,
723 uintptr_t vaddr,
724 level_t level,
725 htable_t *shared)
726 {
727 htable_t *ht = NULL;
728 uint_t is_vlp;
729 uint_t is_bare = 0;
730 uint_t need_to_zero = 1;
731 int kmflags = (can_steal_post_boot ? KM_NOSLEEP : KM_SLEEP);
732
733 if (level < 0 || level > TOP_LEVEL(hat))
734 panic("htable_alloc(): level %d out of range\n", level);
735
736 is_vlp = (hat->hat_flags & HAT_VLP) && level == VLP_LEVEL;
737 if (is_vlp || shared != NULL)
738 is_bare = 1;
739
740 /*
741 * First reuse a cached htable from the hat_ht_cached field, this
742 * avoids unnecessary trips through kmem/page allocators.
743 */
744 if (hat->hat_ht_cached != NULL && !is_bare) {
745 hat_enter(hat);
746 ht = hat->hat_ht_cached;
747 if (ht != NULL) {
748 hat->hat_ht_cached = ht->ht_next;
749 need_to_zero = 0;
750 /* XX64 ASSERT() they're all zero somehow */
751 ASSERT(ht->ht_pfn != PFN_INVALID);
752 }
753 hat_exit(hat);
754 }
755
756 if (ht == NULL) {
757 /*
758 * Allocate an htable, possibly refilling the reserves.
759 */
760 if (USE_HAT_RESERVES()) {
761 ht = htable_get_reserve();
762 } else {
763 /*
764 * Donate successful htable allocations to the reserve.
765 */
766 for (;;) {
767 ht = kmem_cache_alloc(htable_cache, kmflags);
768 if (ht == NULL)
769 break;
770 ht->ht_pfn = PFN_INVALID;
771 if (USE_HAT_RESERVES() ||
772 htable_reserve_cnt >= htable_reserve_amount)
773 break;
774 htable_put_reserve(ht);
775 }
776 }
777
778 /*
779 * allocate a page for the hardware page table if needed
780 */
781 if (ht != NULL && !is_bare) {
782 ht->ht_hat = hat;
783 ht->ht_pfn = ptable_alloc((uintptr_t)ht);
784 if (ht->ht_pfn == PFN_INVALID) {
785 if (USE_HAT_RESERVES())
786 htable_put_reserve(ht);
787 else
788 kmem_cache_free(htable_cache, ht);
789 ht = NULL;
790 }
791 }
792 }
793
794 /*
795 * If allocations failed, kick off a kmem_reap() and resort to
796 * htable steal(). We may spin here if the system is very low on
797 * memory. If the kernel itself has consumed all memory and kmem_reap()
798 * can't free up anything, then we'll really get stuck here.
799 * That should only happen in a system where the administrator has
800 * misconfigured VM parameters via /etc/system.
801 */
802 while (ht == NULL && can_steal_post_boot) {
803 kmem_reap();
804 ht = htable_steal(1);
805 HATSTAT_INC(hs_steals);
806
807 /*
808 * If we stole for a bare htable, release the pagetable page.
809 */
810 if (ht != NULL) {
811 if (is_bare) {
812 ptable_free(ht->ht_pfn);
813 ht->ht_pfn = PFN_INVALID;
814 #if defined(__xpv) && defined(__amd64)
815 /*
816 * make stolen page table writable again in kpm
817 */
818 } else if (kpm_vbase && xen_kpm_page(ht->ht_pfn,
819 PT_VALID | PT_WRITABLE) < 0) {
820 panic("failure making kpm r/w pfn=0x%lx",
821 ht->ht_pfn);
822 #endif
823 }
824 }
825 }
826
827 /*
828 * All attempts to allocate or steal failed. This should only happen
829 * if we run out of memory during boot, due perhaps to a huge
830 * boot_archive. At this point there's no way to continue.
831 */
832 if (ht == NULL)
833 panic("htable_alloc(): couldn't steal\n");
834
835 #if defined(__amd64) && defined(__xpv)
836 /*
837 * Under the 64-bit hypervisor, we have 2 top level page tables.
838 * If this allocation fails, we'll resort to stealing.
839 * We use the stolen page indirectly, by freeing the
840 * stolen htable first.
841 */
842 if (level == mmu.max_level) {
843 for (;;) {
844 htable_t *stolen;
845
846 hat->hat_user_ptable = ptable_alloc((uintptr_t)ht + 1);
847 if (hat->hat_user_ptable != PFN_INVALID)
848 break;
849 stolen = htable_steal(1);
850 if (stolen == NULL)
851 panic("2nd steal ptable failed\n");
852 htable_free(stolen);
853 }
854 block_zero_no_xmm(kpm_vbase + pfn_to_pa(hat->hat_user_ptable),
855 MMU_PAGESIZE);
856 }
857 #endif
858
859 /*
860 * Shared page tables have all entries locked and entries may not
861 * be added or deleted.
862 */
863 ht->ht_flags = 0;
864 if (shared != NULL) {
865 ASSERT(shared->ht_valid_cnt > 0);
866 ht->ht_flags |= HTABLE_SHARED_PFN;
867 ht->ht_pfn = shared->ht_pfn;
868 ht->ht_lock_cnt = 0;
869 ht->ht_valid_cnt = 0; /* updated in hat_share() */
870 ht->ht_shares = shared;
871 need_to_zero = 0;
872 } else {
873 ht->ht_shares = NULL;
874 ht->ht_lock_cnt = 0;
875 ht->ht_valid_cnt = 0;
876 }
877
878 /*
879 * setup flags, etc. for VLP htables
880 */
881 if (is_vlp) {
882 ht->ht_flags |= HTABLE_VLP;
883 ASSERT(ht->ht_pfn == PFN_INVALID);
884 need_to_zero = 0;
885 }
886
887 /*
888 * fill in the htable
889 */
890 ht->ht_hat = hat;
891 ht->ht_parent = NULL;
892 ht->ht_vaddr = vaddr;
893 ht->ht_level = level;
894 ht->ht_busy = 1;
895 ht->ht_next = NULL;
896 ht->ht_prev = NULL;
897
898 /*
899 * Zero out any freshly allocated page table
900 */
901 if (need_to_zero)
902 x86pte_zero(ht, 0, mmu.ptes_per_table);
903
904 #if defined(__amd64) && defined(__xpv)
905 if (!is_bare && kpm_vbase) {
906 (void) xen_kpm_page(ht->ht_pfn, PT_VALID);
907 if (level == mmu.max_level)
908 (void) xen_kpm_page(hat->hat_user_ptable, PT_VALID);
909 }
910 #endif
911
912 return (ht);
913 }
914
915 /*
916 * Free up an htable, either to a hat's cached list, the reserves or
917 * back to kmem.
918 */
919 static void
920 htable_free(htable_t *ht)
921 {
922 hat_t *hat = ht->ht_hat;
923
924 /*
925 * If the process isn't exiting, cache the free htable in the hat
926 * structure. We always do this for the boot time reserve. We don't
927 * do this if the hat is exiting or we are stealing/reaping htables.
928 */
929 if (hat != NULL &&
930 !(ht->ht_flags & HTABLE_SHARED_PFN) &&
931 (use_boot_reserve ||
932 (!(hat->hat_flags & HAT_FREEING) && !htable_dont_cache))) {
933 ASSERT((ht->ht_flags & HTABLE_VLP) == 0);
934 ASSERT(ht->ht_pfn != PFN_INVALID);
935 hat_enter(hat);
936 ht->ht_next = hat->hat_ht_cached;
937 hat->hat_ht_cached = ht;
938 hat_exit(hat);
939 return;
940 }
941
942 /*
943 * If we have a hardware page table, free it.
944 * We don't free page tables that are accessed by sharing.
945 */
946 if (ht->ht_flags & HTABLE_SHARED_PFN) {
947 ASSERT(ht->ht_pfn != PFN_INVALID);
948 } else if (!(ht->ht_flags & HTABLE_VLP)) {
949 ptable_free(ht->ht_pfn);
950 #if defined(__amd64) && defined(__xpv)
951 if (ht->ht_level == mmu.max_level) {
952 ptable_free(hat->hat_user_ptable);
953 hat->hat_user_ptable = PFN_INVALID;
954 }
955 #endif
956 }
957 ht->ht_pfn = PFN_INVALID;
958
959 /*
960 * Free it or put into reserves.
961 */
962 if (USE_HAT_RESERVES() || htable_reserve_cnt < htable_reserve_amount) {
963 htable_put_reserve(ht);
964 } else {
965 kmem_cache_free(htable_cache, ht);
966 htable_adjust_reserve();
967 }
968 }
969
970
971 /*
972 * This is called when a hat is being destroyed or swapped out. We reap all
973 * the remaining htables in the hat cache. If destroying all left over
974 * htables are also destroyed.
975 *
976 * We also don't need to invalidate any of the PTPs nor do any demapping.
977 */
978 void
979 htable_purge_hat(hat_t *hat)
980 {
981 htable_t *ht;
982 int h;
983
984 /*
985 * Purge the htable cache if just reaping.
986 */
987 if (!(hat->hat_flags & HAT_FREEING)) {
988 atomic_add_32(&htable_dont_cache, 1);
989 for (;;) {
990 hat_enter(hat);
991 ht = hat->hat_ht_cached;
992 if (ht == NULL) {
993 hat_exit(hat);
994 break;
995 }
996 hat->hat_ht_cached = ht->ht_next;
997 hat_exit(hat);
998 htable_free(ht);
999 }
1000 atomic_add_32(&htable_dont_cache, -1);
1001 return;
1002 }
1003
1004 /*
1005 * if freeing, no locking is needed
1006 */
1007 while ((ht = hat->hat_ht_cached) != NULL) {
1008 hat->hat_ht_cached = ht->ht_next;
1009 htable_free(ht);
1010 }
1011
1012 /*
1013 * walk thru the htable hash table and free all the htables in it.
1014 */
1015 for (h = 0; h < hat->hat_num_hash; ++h) {
1016 while ((ht = hat->hat_ht_hash[h]) != NULL) {
1017 if (ht->ht_next)
1018 ht->ht_next->ht_prev = ht->ht_prev;
1019
1020 if (ht->ht_prev) {
1021 ht->ht_prev->ht_next = ht->ht_next;
1022 } else {
1023 ASSERT(hat->hat_ht_hash[h] == ht);
1024 hat->hat_ht_hash[h] = ht->ht_next;
1025 }
1026 htable_free(ht);
1027 }
1028 }
1029 }
1030
1031 /*
1032 * Unlink an entry for a table at vaddr and level out of the existing table
1033 * one level higher. We are always holding the HASH_ENTER() when doing this.
1034 */
1035 static void
1036 unlink_ptp(htable_t *higher, htable_t *old, uintptr_t vaddr)
1037 {
1038 uint_t entry = htable_va2entry(vaddr, higher);
1039 x86pte_t expect = MAKEPTP(old->ht_pfn, old->ht_level);
1040 x86pte_t found;
1041 hat_t *hat = old->ht_hat;
1042
1043 ASSERT(higher->ht_busy > 0);
1044 ASSERT(higher->ht_valid_cnt > 0);
1045 ASSERT(old->ht_valid_cnt == 0);
1046 found = x86pte_cas(higher, entry, expect, 0);
1047 #ifdef __xpv
1048 /*
1049 * This is weird, but Xen apparently automatically unlinks empty
1050 * pagetables from the upper page table. So allow PTP to be 0 already.
1051 */
1052 if (found != expect && found != 0)
1053 #else
1054 if (found != expect)
1055 #endif
1056 panic("Bad PTP found=" FMT_PTE ", expected=" FMT_PTE,
1057 found, expect);
1058
1059 /*
1060 * When a top level VLP page table entry changes, we must issue
1061 * a reload of cr3 on all processors.
1062 *
1063 * If we don't need do do that, then we still have to INVLPG against
1064 * an address covered by the inner page table, as the latest processors
1065 * have TLB-like caches for non-leaf page table entries.
1066 */
1067 if (!(hat->hat_flags & HAT_FREEING)) {
1068 hat_tlb_inval(hat, (higher->ht_flags & HTABLE_VLP) ?
1069 DEMAP_ALL_ADDR : old->ht_vaddr);
1070 }
1071
1072 HTABLE_DEC(higher->ht_valid_cnt);
1073 }
1074
1075 /*
1076 * Link an entry for a new table at vaddr and level into the existing table
1077 * one level higher. We are always holding the HASH_ENTER() when doing this.
1078 */
1079 static void
1080 link_ptp(htable_t *higher, htable_t *new, uintptr_t vaddr)
1081 {
1082 uint_t entry = htable_va2entry(vaddr, higher);
1083 x86pte_t newptp = MAKEPTP(new->ht_pfn, new->ht_level);
1084 x86pte_t found;
1085
1086 ASSERT(higher->ht_busy > 0);
1087
1088 ASSERT(new->ht_level != mmu.max_level);
1089
1090 HTABLE_INC(higher->ht_valid_cnt);
1091
1092 found = x86pte_cas(higher, entry, 0, newptp);
1093 if ((found & ~PT_REF) != 0)
1094 panic("HAT: ptp not 0, found=" FMT_PTE, found);
1095
1096 /*
1097 * When any top level VLP page table entry changes, we must issue
1098 * a reload of cr3 on all processors using it.
1099 * We also need to do this for the kernel hat on PAE 32 bit kernel.
1100 */
1101 if (
1102 #ifdef __i386
1103 (higher->ht_hat == kas.a_hat && higher->ht_level == VLP_LEVEL) ||
1104 #endif
1105 (higher->ht_flags & HTABLE_VLP))
1106 hat_tlb_inval(higher->ht_hat, DEMAP_ALL_ADDR);
1107 }
1108
1109 /*
1110 * Release of hold on an htable. If this is the last use and the pagetable
1111 * is empty we may want to free it, then recursively look at the pagetable
1112 * above it. The recursion is handled by the outer while() loop.
1113 *
1114 * On the metal, during process exit, we don't bother unlinking the tables from
1115 * upper level pagetables. They are instead handled in bulk by hat_free_end().
1116 * We can't do this on the hypervisor as we need the page table to be
1117 * implicitly unpinnned before it goes to the free page lists. This can't
1118 * happen unless we fully unlink it from the page table hierarchy.
1119 */
1120 void
1121 htable_release(htable_t *ht)
1122 {
1123 uint_t hashval;
1124 htable_t *shared;
1125 htable_t *higher;
1126 hat_t *hat;
1127 uintptr_t va;
1128 level_t level;
1129
1130 while (ht != NULL) {
1131 shared = NULL;
1132 for (;;) {
1133 hat = ht->ht_hat;
1134 va = ht->ht_vaddr;
1135 level = ht->ht_level;
1136 hashval = HTABLE_HASH(hat, va, level);
1137
1138 /*
1139 * The common case is that this isn't the last use of
1140 * an htable so we don't want to free the htable.
1141 */
1142 HTABLE_ENTER(hashval);
1143 ASSERT(ht->ht_valid_cnt >= 0);
1144 ASSERT(ht->ht_busy > 0);
1145 if (ht->ht_valid_cnt > 0)
1146 break;
1147 if (ht->ht_busy > 1)
1148 break;
1149 ASSERT(ht->ht_lock_cnt == 0);
1150
1151 #if !defined(__xpv)
1152 /*
1153 * we always release empty shared htables
1154 */
1155 if (!(ht->ht_flags & HTABLE_SHARED_PFN)) {
1156
1157 /*
1158 * don't release if in address space tear down
1159 */
1160 if (hat->hat_flags & HAT_FREEING)
1161 break;
1162
1163 /*
1164 * At and above max_page_level, free if it's for
1165 * a boot-time kernel mapping below kernelbase.
1166 */
1167 if (level >= mmu.max_page_level &&
1168 (hat != kas.a_hat || va >= kernelbase))
1169 break;
1170 }
1171 #endif /* __xpv */
1172
1173 /*
1174 * Remember if we destroy an htable that shares its PFN
1175 * from elsewhere.
1176 */
1177 if (ht->ht_flags & HTABLE_SHARED_PFN) {
1178 ASSERT(shared == NULL);
1179 shared = ht->ht_shares;
1180 HATSTAT_INC(hs_htable_unshared);
1181 }
1182
1183 /*
1184 * Handle release of a table and freeing the htable_t.
1185 * Unlink it from the table higher (ie. ht_parent).
1186 */
1187 higher = ht->ht_parent;
1188 ASSERT(higher != NULL);
1189
1190 /*
1191 * Unlink the pagetable.
1192 */
1193 unlink_ptp(higher, ht, va);
1194
1195 /*
1196 * remove this htable from its hash list
1197 */
1198 if (ht->ht_next)
1199 ht->ht_next->ht_prev = ht->ht_prev;
1200
1201 if (ht->ht_prev) {
1202 ht->ht_prev->ht_next = ht->ht_next;
1203 } else {
1204 ASSERT(hat->hat_ht_hash[hashval] == ht);
1205 hat->hat_ht_hash[hashval] = ht->ht_next;
1206 }
1207 HTABLE_EXIT(hashval);
1208 htable_free(ht);
1209 ht = higher;
1210 }
1211
1212 ASSERT(ht->ht_busy >= 1);
1213 --ht->ht_busy;
1214 HTABLE_EXIT(hashval);
1215
1216 /*
1217 * If we released a shared htable, do a release on the htable
1218 * from which it shared
1219 */
1220 ht = shared;
1221 }
1222 }
1223
1224 /*
1225 * Find the htable for the pagetable at the given level for the given address.
1226 * If found acquires a hold that eventually needs to be htable_release()d
1227 */
1228 htable_t *
1229 htable_lookup(hat_t *hat, uintptr_t vaddr, level_t level)
1230 {
1231 uintptr_t base;
1232 uint_t hashval;
1233 htable_t *ht = NULL;
1234
1235 ASSERT(level >= 0);
1236 ASSERT(level <= TOP_LEVEL(hat));
1237
1238 if (level == TOP_LEVEL(hat)) {
1239 #if defined(__amd64)
1240 /*
1241 * 32 bit address spaces on 64 bit kernels need to check
1242 * for overflow of the 32 bit address space
1243 */
1244 if ((hat->hat_flags & HAT_VLP) && vaddr >= ((uint64_t)1 << 32))
1245 return (NULL);
1246 #endif
1247 base = 0;
1248 } else {
1249 base = vaddr & LEVEL_MASK(level + 1);
1250 }
1251
1252 hashval = HTABLE_HASH(hat, base, level);
1253 HTABLE_ENTER(hashval);
1254 for (ht = hat->hat_ht_hash[hashval]; ht; ht = ht->ht_next) {
1255 if (ht->ht_hat == hat &&
1256 ht->ht_vaddr == base &&
1257 ht->ht_level == level)
1258 break;
1259 }
1260 if (ht)
1261 ++ht->ht_busy;
1262
1263 HTABLE_EXIT(hashval);
1264 return (ht);
1265 }
1266
1267 /*
1268 * Acquires a hold on a known htable (from a locked hment entry).
1269 */
1270 void
1271 htable_acquire(htable_t *ht)
1272 {
1273 hat_t *hat = ht->ht_hat;
1274 level_t level = ht->ht_level;
1275 uintptr_t base = ht->ht_vaddr;
1276 uint_t hashval = HTABLE_HASH(hat, base, level);
1277
1278 HTABLE_ENTER(hashval);
1279 #ifdef DEBUG
1280 /*
1281 * make sure the htable is there
1282 */
1283 {
1284 htable_t *h;
1285
1286 for (h = hat->hat_ht_hash[hashval];
1287 h && h != ht;
1288 h = h->ht_next)
1289 ;
1290 ASSERT(h == ht);
1291 }
1292 #endif /* DEBUG */
1293 ++ht->ht_busy;
1294 HTABLE_EXIT(hashval);
1295 }
1296
1297 /*
1298 * Find the htable for the pagetable at the given level for the given address.
1299 * If found acquires a hold that eventually needs to be htable_release()d
1300 * If not found the table is created.
1301 *
1302 * Since we can't hold a hash table mutex during allocation, we have to
1303 * drop it and redo the search on a create. Then we may have to free the newly
1304 * allocated htable if another thread raced in and created it ahead of us.
1305 */
1306 htable_t *
1307 htable_create(
1308 hat_t *hat,
1309 uintptr_t vaddr,
1310 level_t level,
1311 htable_t *shared)
1312 {
1313 uint_t h;
1314 level_t l;
1315 uintptr_t base;
1316 htable_t *ht;
1317 htable_t *higher = NULL;
1318 htable_t *new = NULL;
1319
1320 if (level < 0 || level > TOP_LEVEL(hat))
1321 panic("htable_create(): level %d out of range\n", level);
1322
1323 /*
1324 * Create the page tables in top down order.
1325 */
1326 for (l = TOP_LEVEL(hat); l >= level; --l) {
1327 new = NULL;
1328 if (l == TOP_LEVEL(hat))
1329 base = 0;
1330 else
1331 base = vaddr & LEVEL_MASK(l + 1);
1332
1333 h = HTABLE_HASH(hat, base, l);
1334 try_again:
1335 /*
1336 * look up the htable at this level
1337 */
1338 HTABLE_ENTER(h);
1339 if (l == TOP_LEVEL(hat)) {
1340 ht = hat->hat_htable;
1341 } else {
1342 for (ht = hat->hat_ht_hash[h]; ht; ht = ht->ht_next) {
1343 ASSERT(ht->ht_hat == hat);
1344 if (ht->ht_vaddr == base &&
1345 ht->ht_level == l)
1346 break;
1347 }
1348 }
1349
1350 /*
1351 * if we found the htable, increment its busy cnt
1352 * and if we had allocated a new htable, free it.
1353 */
1354 if (ht != NULL) {
1355 /*
1356 * If we find a pre-existing shared table, it must
1357 * share from the same place.
1358 */
1359 if (l == level && shared && ht->ht_shares &&
1360 ht->ht_shares != shared) {
1361 panic("htable shared from wrong place "
1362 "found htable=%p shared=%p",
1363 (void *)ht, (void *)shared);
1364 }
1365 ++ht->ht_busy;
1366 HTABLE_EXIT(h);
1367 if (new)
1368 htable_free(new);
1369 if (higher != NULL)
1370 htable_release(higher);
1371 higher = ht;
1372
1373 /*
1374 * if we didn't find it on the first search
1375 * allocate a new one and search again
1376 */
1377 } else if (new == NULL) {
1378 HTABLE_EXIT(h);
1379 new = htable_alloc(hat, base, l,
1380 l == level ? shared : NULL);
1381 goto try_again;
1382
1383 /*
1384 * 2nd search and still not there, use "new" table
1385 * Link new table into higher, when not at top level.
1386 */
1387 } else {
1388 ht = new;
1389 if (higher != NULL) {
1390 link_ptp(higher, ht, base);
1391 ht->ht_parent = higher;
1392 }
1393 ht->ht_next = hat->hat_ht_hash[h];
1394 ASSERT(ht->ht_prev == NULL);
1395 if (hat->hat_ht_hash[h])
1396 hat->hat_ht_hash[h]->ht_prev = ht;
1397 hat->hat_ht_hash[h] = ht;
1398 HTABLE_EXIT(h);
1399
1400 /*
1401 * Note we don't do htable_release(higher).
1402 * That happens recursively when "new" is removed by
1403 * htable_release() or htable_steal().
1404 */
1405 higher = ht;
1406
1407 /*
1408 * If we just created a new shared page table we
1409 * increment the shared htable's busy count, so that
1410 * it can't be the victim of a steal even if it's empty.
1411 */
1412 if (l == level && shared) {
1413 (void) htable_lookup(shared->ht_hat,
1414 shared->ht_vaddr, shared->ht_level);
1415 HATSTAT_INC(hs_htable_shared);
1416 }
1417 }
1418 }
1419
1420 return (ht);
1421 }
1422
1423 /*
1424 * Inherit initial pagetables from the boot program. On the 64-bit
1425 * hypervisor we also temporarily mark the p_index field of page table
1426 * pages, so we know not to try making them writable in seg_kpm.
1427 */
1428 void
1429 htable_attach(
1430 hat_t *hat,
1431 uintptr_t base,
1432 level_t level,
1433 htable_t *parent,
1434 pfn_t pfn)
1435 {
1436 htable_t *ht;
1437 uint_t h;
1438 uint_t i;
1439 x86pte_t pte;
1440 x86pte_t *ptep;
1441 page_t *pp;
1442 extern page_t *boot_claim_page(pfn_t);
1443
1444 ht = htable_get_reserve();
1445 if (level == mmu.max_level)
1446 kas.a_hat->hat_htable = ht;
1447 ht->ht_hat = hat;
1448 ht->ht_parent = parent;
1449 ht->ht_vaddr = base;
1450 ht->ht_level = level;
1451 ht->ht_busy = 1;
1452 ht->ht_next = NULL;
1453 ht->ht_prev = NULL;
1454 ht->ht_flags = 0;
1455 ht->ht_pfn = pfn;
1456 ht->ht_lock_cnt = 0;
1457 ht->ht_valid_cnt = 0;
1458 if (parent != NULL)
1459 ++parent->ht_busy;
1460
1461 h = HTABLE_HASH(hat, base, level);
1462 HTABLE_ENTER(h);
1463 ht->ht_next = hat->hat_ht_hash[h];
1464 ASSERT(ht->ht_prev == NULL);
1465 if (hat->hat_ht_hash[h])
1466 hat->hat_ht_hash[h]->ht_prev = ht;
1467 hat->hat_ht_hash[h] = ht;
1468 HTABLE_EXIT(h);
1469
1470 /*
1471 * make sure the page table physical page is not FREE
1472 */
1473 if (page_resv(1, KM_NOSLEEP) == 0)
1474 panic("page_resv() failed in ptable alloc");
1475
1476 pp = boot_claim_page(pfn);
1477 ASSERT(pp != NULL);
1478
1479 /*
1480 * Page table pages that were allocated by dboot or
1481 * in very early startup didn't go through boot_mapin()
1482 * and so won't have vnode/offsets. Fix that here.
1483 */
1484 if (pp->p_vnode == NULL) {
1485 /* match offset calculation in page_get_physical() */
1486 u_offset_t offset = (uintptr_t)ht;
1487 if (offset > kernelbase)
1488 offset -= kernelbase;
1489 offset <<= MMU_PAGESHIFT;
1490 #if defined(__amd64)
1491 offset += mmu.hole_start; /* something in VA hole */
1492 #else
1493 offset += 1ULL << 40; /* something > 4 Gig */
1494 #endif
1495 ASSERT(page_exists(&kvp, offset) == NULL);
1496 (void) page_hashin(pp, &kvp, offset, NULL);
1497 }
1498 page_downgrade(pp);
1499 #if defined(__xpv) && defined(__amd64)
1500 /*
1501 * Record in the page_t that is a pagetable for segkpm setup.
1502 */
1503 if (kpm_vbase)
1504 pp->p_index = 1;
1505 #endif
1506
1507 /*
1508 * Count valid mappings and recursively attach lower level pagetables.
1509 */
1510 ptep = kbm_remap_window(pfn_to_pa(pfn), 0);
1511 for (i = 0; i < HTABLE_NUM_PTES(ht); ++i) {
1512 if (mmu.pae_hat)
1513 pte = ptep[i];
1514 else
1515 pte = ((x86pte32_t *)ptep)[i];
1516 if (!IN_HYPERVISOR_VA(base) && PTE_ISVALID(pte)) {
1517 ++ht->ht_valid_cnt;
1518 if (!PTE_ISPAGE(pte, level)) {
1519 htable_attach(hat, base, level - 1,
1520 ht, PTE2PFN(pte, level));
1521 ptep = kbm_remap_window(pfn_to_pa(pfn), 0);
1522 }
1523 }
1524 base += LEVEL_SIZE(level);
1525 if (base == mmu.hole_start)
1526 base = (mmu.hole_end + MMU_PAGEOFFSET) & MMU_PAGEMASK;
1527 }
1528
1529 /*
1530 * As long as all the mappings we had were below kernel base
1531 * we can release the htable.
1532 */
1533 if (base < kernelbase)
1534 htable_release(ht);
1535 }
1536
1537 /*
1538 * Walk through a given htable looking for the first valid entry. This
1539 * routine takes both a starting and ending address. The starting address
1540 * is required to be within the htable provided by the caller, but there is
1541 * no such restriction on the ending address.
1542 *
1543 * If the routine finds a valid entry in the htable (at or beyond the
1544 * starting address), the PTE (and its address) will be returned.
1545 * This PTE may correspond to either a page or a pagetable - it is the
1546 * caller's responsibility to determine which. If no valid entry is
1547 * found, 0 (and invalid PTE) and the next unexamined address will be
1548 * returned.
1549 *
1550 * The loop has been carefully coded for optimization.
1551 */
1552 static x86pte_t
1553 htable_scan(htable_t *ht, uintptr_t *vap, uintptr_t eaddr)
1554 {
1555 uint_t e;
1556 x86pte_t found_pte = (x86pte_t)0;
1557 caddr_t pte_ptr;
1558 caddr_t end_pte_ptr;
1559 int l = ht->ht_level;
1560 uintptr_t va = *vap & LEVEL_MASK(l);
1561 size_t pgsize = LEVEL_SIZE(l);
1562
1563 ASSERT(va >= ht->ht_vaddr);
1564 ASSERT(va <= HTABLE_LAST_PAGE(ht));
1565
1566 /*
1567 * Compute the starting index and ending virtual address
1568 */
1569 e = htable_va2entry(va, ht);
1570
1571 /*
1572 * The following page table scan code knows that the valid
1573 * bit of a PTE is in the lowest byte AND that x86 is little endian!!
1574 */
1575 pte_ptr = (caddr_t)x86pte_access_pagetable(ht, 0);
1576 end_pte_ptr = (caddr_t)PT_INDEX_PTR(pte_ptr, HTABLE_NUM_PTES(ht));
1577 pte_ptr = (caddr_t)PT_INDEX_PTR((x86pte_t *)pte_ptr, e);
1578 while (!PTE_ISVALID(*pte_ptr)) {
1579 va += pgsize;
1580 if (va >= eaddr)
1581 break;
1582 pte_ptr += mmu.pte_size;
1583 ASSERT(pte_ptr <= end_pte_ptr);
1584 if (pte_ptr == end_pte_ptr)
1585 break;
1586 }
1587
1588 /*
1589 * if we found a valid PTE, load the entire PTE
1590 */
1591 if (va < eaddr && pte_ptr != end_pte_ptr)
1592 found_pte = GET_PTE((x86pte_t *)pte_ptr);
1593 x86pte_release_pagetable(ht);
1594
1595 #if defined(__amd64)
1596 /*
1597 * deal with VA hole on amd64
1598 */
1599 if (l == mmu.max_level && va >= mmu.hole_start && va <= mmu.hole_end)
1600 va = mmu.hole_end + va - mmu.hole_start;
1601 #endif /* __amd64 */
1602
1603 *vap = va;
1604 return (found_pte);
1605 }
1606
1607 /*
1608 * Find the address and htable for the first populated translation at or
1609 * above the given virtual address. The caller may also specify an upper
1610 * limit to the address range to search. Uses level information to quickly
1611 * skip unpopulated sections of virtual address spaces.
1612 *
1613 * If not found returns NULL. When found, returns the htable and virt addr
1614 * and has a hold on the htable.
1615 */
1616 x86pte_t
1617 htable_walk(
1618 struct hat *hat,
1619 htable_t **htp,
1620 uintptr_t *vaddr,
1621 uintptr_t eaddr)
1622 {
1623 uintptr_t va = *vaddr;
1624 htable_t *ht;
1625 htable_t *prev = *htp;
1626 level_t l;
1627 level_t max_mapped_level;
1628 x86pte_t pte;
1629
1630 ASSERT(eaddr > va);
1631
1632 /*
1633 * If this is a user address, then we know we need not look beyond
1634 * kernelbase.
1635 */
1636 ASSERT(hat == kas.a_hat || eaddr <= kernelbase ||
1637 eaddr == HTABLE_WALK_TO_END);
1638 if (hat != kas.a_hat && eaddr == HTABLE_WALK_TO_END)
1639 eaddr = kernelbase;
1640
1641 /*
1642 * If we're coming in with a previous page table, search it first
1643 * without doing an htable_lookup(), this should be frequent.
1644 */
1645 if (prev) {
1646 ASSERT(prev->ht_busy > 0);
1647 ASSERT(prev->ht_vaddr <= va);
1648 l = prev->ht_level;
1649 if (va <= HTABLE_LAST_PAGE(prev)) {
1650 pte = htable_scan(prev, &va, eaddr);
1651
1652 if (PTE_ISPAGE(pte, l)) {
1653 *vaddr = va;
1654 *htp = prev;
1655 return (pte);
1656 }
1657 }
1658
1659 /*
1660 * We found nothing in the htable provided by the caller,
1661 * so fall through and do the full search
1662 */
1663 htable_release(prev);
1664 }
1665
1666 /*
1667 * Find the level of the largest pagesize used by this HAT.
1668 */
1669 if (hat->hat_ism_pgcnt > 0) {
1670 max_mapped_level = mmu.umax_page_level;
1671 } else {
1672 max_mapped_level = 0;
1673 for (l = 1; l <= mmu.max_page_level; ++l)
1674 if (hat->hat_pages_mapped[l] != 0)
1675 max_mapped_level = l;
1676 }
1677
1678 while (va < eaddr && va >= *vaddr) {
1679 ASSERT(!IN_VA_HOLE(va));
1680
1681 /*
1682 * Find lowest table with any entry for given address.
1683 */
1684 for (l = 0; l <= TOP_LEVEL(hat); ++l) {
1685 ht = htable_lookup(hat, va, l);
1686 if (ht != NULL) {
1687 pte = htable_scan(ht, &va, eaddr);
1688 if (PTE_ISPAGE(pte, l)) {
1689 *vaddr = va;
1690 *htp = ht;
1691 return (pte);
1692 }
1693 htable_release(ht);
1694 break;
1695 }
1696
1697 /*
1698 * No htable at this level for the address. If there
1699 * is no larger page size that could cover it, we can
1700 * skip right to the start of the next page table.
1701 */
1702 ASSERT(l < TOP_LEVEL(hat));
1703 if (l >= max_mapped_level) {
1704 va = NEXT_ENTRY_VA(va, l + 1);
1705 if (va >= eaddr)
1706 break;
1707 }
1708 }
1709 }
1710
1711 *vaddr = 0;
1712 *htp = NULL;
1713 return (0);
1714 }
1715
1716 /*
1717 * Find the htable and page table entry index of the given virtual address
1718 * with pagesize at or below given level.
1719 * If not found returns NULL. When found, returns the htable, sets
1720 * entry, and has a hold on the htable.
1721 */
1722 htable_t *
1723 htable_getpte(
1724 struct hat *hat,
1725 uintptr_t vaddr,
1726 uint_t *entry,
1727 x86pte_t *pte,
1728 level_t level)
1729 {
1730 htable_t *ht;
1731 level_t l;
1732 uint_t e;
1733
1734 ASSERT(level <= mmu.max_page_level);
1735
1736 for (l = 0; l <= level; ++l) {
1737 ht = htable_lookup(hat, vaddr, l);
1738 if (ht == NULL)
1739 continue;
1740 e = htable_va2entry(vaddr, ht);
1741 if (entry != NULL)
1742 *entry = e;
1743 if (pte != NULL)
1744 *pte = x86pte_get(ht, e);
1745 return (ht);
1746 }
1747 return (NULL);
1748 }
1749
1750 /*
1751 * Find the htable and page table entry index of the given virtual address.
1752 * There must be a valid page mapped at the given address.
1753 * If not found returns NULL. When found, returns the htable, sets
1754 * entry, and has a hold on the htable.
1755 */
1756 htable_t *
1757 htable_getpage(struct hat *hat, uintptr_t vaddr, uint_t *entry)
1758 {
1759 htable_t *ht;
1760 uint_t e;
1761 x86pte_t pte;
1762
1763 ht = htable_getpte(hat, vaddr, &e, &pte, mmu.max_page_level);
1764 if (ht == NULL)
1765 return (NULL);
1766
1767 if (entry)
1768 *entry = e;
1769
1770 if (PTE_ISPAGE(pte, ht->ht_level))
1771 return (ht);
1772 htable_release(ht);
1773 return (NULL);
1774 }
1775
1776
1777 void
1778 htable_init()
1779 {
1780 /*
1781 * To save on kernel VA usage, we avoid debug information in 32 bit
1782 * kernels.
1783 */
1784 #if defined(__amd64)
1785 int kmem_flags = KMC_NOHASH;
1786 #elif defined(__i386)
1787 int kmem_flags = KMC_NOHASH | KMC_NODEBUG;
1788 #endif
1789
1790 /*
1791 * initialize kmem caches
1792 */
1793 htable_cache = kmem_cache_create("htable_t",
1794 sizeof (htable_t), 0, NULL, NULL,
1795 htable_reap, NULL, hat_memload_arena, kmem_flags);
1796 }
1797
1798 /*
1799 * get the pte index for the virtual address in the given htable's pagetable
1800 */
1801 uint_t
1802 htable_va2entry(uintptr_t va, htable_t *ht)
1803 {
1804 level_t l = ht->ht_level;
1805
1806 ASSERT(va >= ht->ht_vaddr);
1807 ASSERT(va <= HTABLE_LAST_PAGE(ht));
1808 return ((va >> LEVEL_SHIFT(l)) & (HTABLE_NUM_PTES(ht) - 1));
1809 }
1810
1811 /*
1812 * Given an htable and the index of a pte in it, return the virtual address
1813 * of the page.
1814 */
1815 uintptr_t
1816 htable_e2va(htable_t *ht, uint_t entry)
1817 {
1818 level_t l = ht->ht_level;
1819 uintptr_t va;
1820
1821 ASSERT(entry < HTABLE_NUM_PTES(ht));
1822 va = ht->ht_vaddr + ((uintptr_t)entry << LEVEL_SHIFT(l));
1823
1824 /*
1825 * Need to skip over any VA hole in top level table
1826 */
1827 #if defined(__amd64)
1828 if (ht->ht_level == mmu.max_level && va >= mmu.hole_start)
1829 va += ((mmu.hole_end - mmu.hole_start) + 1);
1830 #endif
1831
1832 return (va);
1833 }
1834
1835 /*
1836 * The code uses compare and swap instructions to read/write PTE's to
1837 * avoid atomicity problems, since PTEs can be 8 bytes on 32 bit systems.
1838 * will naturally be atomic.
1839 *
1840 * The combination of using kpreempt_disable()/_enable() and the hci_mutex
1841 * are used to ensure that an interrupt won't overwrite a temporary mapping
1842 * while it's in use. If an interrupt thread tries to access a PTE, it will
1843 * yield briefly back to the pinned thread which holds the cpu's hci_mutex.
1844 */
1845 void
1846 x86pte_cpu_init(cpu_t *cpu)
1847 {
1848 struct hat_cpu_info *hci;
1849
1850 hci = kmem_zalloc(sizeof (*hci), KM_SLEEP);
1851 mutex_init(&hci->hci_mutex, NULL, MUTEX_DEFAULT, NULL);
1852 cpu->cpu_hat_info = hci;
1853 }
1854
1855 void
1856 x86pte_cpu_fini(cpu_t *cpu)
1857 {
1858 struct hat_cpu_info *hci = cpu->cpu_hat_info;
1859
1860 kmem_free(hci, sizeof (*hci));
1861 cpu->cpu_hat_info = NULL;
1862 }
1863
1864 #ifdef __i386
1865 /*
1866 * On 32 bit kernels, loading a 64 bit PTE is a little tricky
1867 */
1868 x86pte_t
1869 get_pte64(x86pte_t *ptr)
1870 {
1871 volatile uint32_t *p = (uint32_t *)ptr;
1872 x86pte_t t;
1873
1874 ASSERT(mmu.pae_hat != 0);
1875 for (;;) {
1876 t = p[0];
1877 t |= (uint64_t)p[1] << 32;
1878 if ((t & 0xffffffff) == p[0])
1879 return (t);
1880 }
1881 }
1882 #endif /* __i386 */
1883
1884 /*
1885 * Disable preemption and establish a mapping to the pagetable with the
1886 * given pfn. This is optimized for there case where it's the same
1887 * pfn as we last used referenced from this CPU.
1888 */
1889 static x86pte_t *
1890 x86pte_access_pagetable(htable_t *ht, uint_t index)
1891 {
1892 /*
1893 * VLP pagetables are contained in the hat_t
1894 */
1895 if (ht->ht_flags & HTABLE_VLP)
1896 return (PT_INDEX_PTR(ht->ht_hat->hat_vlp_ptes, index));
1897 return (x86pte_mapin(ht->ht_pfn, index, ht));
1898 }
1899
1900 /*
1901 * map the given pfn into the page table window.
1902 */
1903 /*ARGSUSED*/
1904 x86pte_t *
1905 x86pte_mapin(pfn_t pfn, uint_t index, htable_t *ht)
1906 {
1907 x86pte_t *pteptr;
1908 x86pte_t pte = 0;
1909 x86pte_t newpte;
1910 int x;
1911
1912 ASSERT(pfn != PFN_INVALID);
1913
1914 if (!khat_running) {
1915 caddr_t va = kbm_remap_window(pfn_to_pa(pfn), 1);
1916 return (PT_INDEX_PTR(va, index));
1917 }
1918
1919 /*
1920 * If kpm is available, use it.
1921 */
1922 if (kpm_vbase)
1923 return (PT_INDEX_PTR(hat_kpm_pfn2va(pfn), index));
1924
1925 /*
1926 * Disable preemption and grab the CPU's hci_mutex
1927 */
1928 kpreempt_disable();
1929 ASSERT(CPU->cpu_hat_info != NULL);
1930 mutex_enter(&CPU->cpu_hat_info->hci_mutex);
1931 x = PWIN_TABLE(CPU->cpu_id);
1932 pteptr = (x86pte_t *)PWIN_PTE_VA(x);
1933 #ifndef __xpv
1934 if (mmu.pae_hat)
1935 pte = *pteptr;
1936 else
1937 pte = *(x86pte32_t *)pteptr;
1938 #endif
1939
1940 newpte = MAKEPTE(pfn, 0) | mmu.pt_global | mmu.pt_nx;
1941
1942 /*
1943 * For hardware we can use a writable mapping.
1944 */
1945 #ifdef __xpv
1946 if (IN_XPV_PANIC())
1947 #endif
1948 newpte |= PT_WRITABLE;
1949
1950 if (!PTE_EQUIV(newpte, pte)) {
1951
1952 #ifdef __xpv
1953 if (!IN_XPV_PANIC()) {
1954 xen_map(newpte, PWIN_VA(x));
1955 } else
1956 #endif
1957 {
1958 XPV_ALLOW_PAGETABLE_UPDATES();
1959 if (mmu.pae_hat)
1960 *pteptr = newpte;
1961 else
1962 *(x86pte32_t *)pteptr = newpte;
1963 XPV_DISALLOW_PAGETABLE_UPDATES();
1964 mmu_tlbflush_entry((caddr_t)(PWIN_VA(x)));
1965 }
1966 }
1967 return (PT_INDEX_PTR(PWIN_VA(x), index));
1968 }
1969
1970 /*
1971 * Release access to a page table.
1972 */
1973 static void
1974 x86pte_release_pagetable(htable_t *ht)
1975 {
1976 /*
1977 * nothing to do for VLP htables
1978 */
1979 if (ht->ht_flags & HTABLE_VLP)
1980 return;
1981
1982 x86pte_mapout();
1983 }
1984
1985 void
1986 x86pte_mapout(void)
1987 {
1988 if (kpm_vbase != NULL || !khat_running)
1989 return;
1990
1991 /*
1992 * Drop the CPU's hci_mutex and restore preemption.
1993 */
1994 #ifdef __xpv
1995 if (!IN_XPV_PANIC()) {
1996 uintptr_t va;
1997
1998 /*
1999 * We need to always clear the mapping in case a page
2000 * that was once a page table page is ballooned out.
2001 */
2002 va = (uintptr_t)PWIN_VA(PWIN_TABLE(CPU->cpu_id));
2003 (void) HYPERVISOR_update_va_mapping(va, 0,
2004 UVMF_INVLPG | UVMF_LOCAL);
2005 }
2006 #endif
2007 mutex_exit(&CPU->cpu_hat_info->hci_mutex);
2008 kpreempt_enable();
2009 }
2010
2011 /*
2012 * Atomic retrieval of a pagetable entry
2013 */
2014 x86pte_t
2015 x86pte_get(htable_t *ht, uint_t entry)
2016 {
2017 x86pte_t pte;
2018 x86pte_t *ptep;
2019
2020 /*
2021 * Be careful that loading PAE entries in 32 bit kernel is atomic.
2022 */
2023 ASSERT(entry < mmu.ptes_per_table);
2024 ptep = x86pte_access_pagetable(ht, entry);
2025 pte = GET_PTE(ptep);
2026 x86pte_release_pagetable(ht);
2027 return (pte);
2028 }
2029
2030 /*
2031 * Atomic unconditional set of a page table entry, it returns the previous
2032 * value. For pre-existing mappings if the PFN changes, then we don't care
2033 * about the old pte's REF / MOD bits. If the PFN remains the same, we leave
2034 * the MOD/REF bits unchanged.
2035 *
2036 * If asked to overwrite a link to a lower page table with a large page
2037 * mapping, this routine returns the special value of LPAGE_ERROR. This
2038 * allows the upper HAT layers to retry with a smaller mapping size.
2039 */
2040 x86pte_t
2041 x86pte_set(htable_t *ht, uint_t entry, x86pte_t new, void *ptr)
2042 {
2043 x86pte_t old;
2044 x86pte_t prev;
2045 x86pte_t *ptep;
2046 level_t l = ht->ht_level;
2047 x86pte_t pfn_mask = (l != 0) ? PT_PADDR_LGPG : PT_PADDR;
2048 x86pte_t n;
2049 uintptr_t addr = htable_e2va(ht, entry);
2050 hat_t *hat = ht->ht_hat;
2051
2052 ASSERT(new != 0); /* don't use to invalidate a PTE, see x86pte_update */
2053 ASSERT(!(ht->ht_flags & HTABLE_SHARED_PFN));
2054 if (ptr == NULL)
2055 ptep = x86pte_access_pagetable(ht, entry);
2056 else
2057 ptep = ptr;
2058
2059 /*
2060 * Install the new PTE. If remapping the same PFN, then
2061 * copy existing REF/MOD bits to new mapping.
2062 */
2063 do {
2064 prev = GET_PTE(ptep);
2065 n = new;
2066 if (PTE_ISVALID(n) && (prev & pfn_mask) == (new & pfn_mask))
2067 n |= prev & (PT_REF | PT_MOD);
2068
2069 /*
2070 * Another thread may have installed this mapping already,
2071 * flush the local TLB and be done.
2072 */
2073 if (prev == n) {
2074 old = new;
2075 #ifdef __xpv
2076 if (!IN_XPV_PANIC())
2077 xen_flush_va((caddr_t)addr);
2078 else
2079 #endif
2080 mmu_tlbflush_entry((caddr_t)addr);
2081 goto done;
2082 }
2083
2084 /*
2085 * Detect if we have a collision of installing a large
2086 * page mapping where there already is a lower page table.
2087 */
2088 if (l > 0 && (prev & PT_VALID) && !(prev & PT_PAGESIZE)) {
2089 old = LPAGE_ERROR;
2090 goto done;
2091 }
2092
2093 XPV_ALLOW_PAGETABLE_UPDATES();
2094 old = CAS_PTE(ptep, prev, n);
2095 XPV_DISALLOW_PAGETABLE_UPDATES();
2096 } while (old != prev);
2097
2098 /*
2099 * Do a TLB demap if needed, ie. the old pte was valid.
2100 *
2101 * Note that a stale TLB writeback to the PTE here either can't happen
2102 * or doesn't matter. The PFN can only change for NOSYNC|NOCONSIST
2103 * mappings, but they were created with REF and MOD already set, so
2104 * no stale writeback will happen.
2105 *
2106 * Segmap is the only place where remaps happen on the same pfn and for
2107 * that we want to preserve the stale REF/MOD bits.
2108 */
2109 if (old & PT_REF)
2110 hat_tlb_inval(hat, addr);
2111
2112 done:
2113 if (ptr == NULL)
2114 x86pte_release_pagetable(ht);
2115 return (old);
2116 }
2117
2118 /*
2119 * Atomic compare and swap of a page table entry. No TLB invalidates are done.
2120 * This is used for links between pagetables of different levels.
2121 * Note we always create these links with dirty/access set, so they should
2122 * never change.
2123 */
2124 x86pte_t
2125 x86pte_cas(htable_t *ht, uint_t entry, x86pte_t old, x86pte_t new)
2126 {
2127 x86pte_t pte;
2128 x86pte_t *ptep;
2129 #ifdef __xpv
2130 /*
2131 * We can't use writable pagetables for upper level tables, so fake it.
2132 */
2133 mmu_update_t t[2];
2134 int cnt = 1;
2135 int count;
2136 maddr_t ma;
2137
2138 if (!IN_XPV_PANIC()) {
2139 ASSERT(!(ht->ht_flags & HTABLE_VLP)); /* no VLP yet */
2140 ma = pa_to_ma(PT_INDEX_PHYSADDR(pfn_to_pa(ht->ht_pfn), entry));
2141 t[0].ptr = ma | MMU_NORMAL_PT_UPDATE;
2142 t[0].val = new;
2143
2144 #if defined(__amd64)
2145 /*
2146 * On the 64-bit hypervisor we need to maintain the user mode
2147 * top page table too.
2148 */
2149 if (ht->ht_level == mmu.max_level && ht->ht_hat != kas.a_hat) {
2150 ma = pa_to_ma(PT_INDEX_PHYSADDR(pfn_to_pa(
2151 ht->ht_hat->hat_user_ptable), entry));
2152 t[1].ptr = ma | MMU_NORMAL_PT_UPDATE;
2153 t[1].val = new;
2154 ++cnt;
2155 }
2156 #endif /* __amd64 */
2157
2158 if (HYPERVISOR_mmu_update(t, cnt, &count, DOMID_SELF))
2159 panic("HYPERVISOR_mmu_update() failed");
2160 ASSERT(count == cnt);
2161 return (old);
2162 }
2163 #endif
2164 ptep = x86pte_access_pagetable(ht, entry);
2165 XPV_ALLOW_PAGETABLE_UPDATES();
2166 pte = CAS_PTE(ptep, old, new);
2167 XPV_DISALLOW_PAGETABLE_UPDATES();
2168 x86pte_release_pagetable(ht);
2169 return (pte);
2170 }
2171
2172 /*
2173 * Invalidate a page table entry as long as it currently maps something that
2174 * matches the value determined by expect.
2175 *
2176 * Also invalidates any TLB entries and returns the previous value of the PTE.
2177 */
2178 x86pte_t
2179 x86pte_inval(
2180 htable_t *ht,
2181 uint_t entry,
2182 x86pte_t expect,
2183 x86pte_t *pte_ptr)
2184 {
2185 x86pte_t *ptep;
2186 x86pte_t oldpte;
2187 x86pte_t found;
2188
2189 ASSERT(!(ht->ht_flags & HTABLE_SHARED_PFN));
2190 ASSERT(ht->ht_level <= mmu.max_page_level);
2191
2192 if (pte_ptr != NULL)
2193 ptep = pte_ptr;
2194 else
2195 ptep = x86pte_access_pagetable(ht, entry);
2196
2197 #if defined(__xpv)
2198 /*
2199 * If exit()ing just use HYPERVISOR_mmu_update(), as we can't be racing
2200 * with anything else.
2201 */
2202 if ((ht->ht_hat->hat_flags & HAT_FREEING) && !IN_XPV_PANIC()) {
2203 int count;
2204 mmu_update_t t[1];
2205 maddr_t ma;
2206
2207 oldpte = GET_PTE(ptep);
2208 if (expect != 0 && (oldpte & PT_PADDR) != (expect & PT_PADDR))
2209 goto done;
2210 ma = pa_to_ma(PT_INDEX_PHYSADDR(pfn_to_pa(ht->ht_pfn), entry));
2211 t[0].ptr = ma | MMU_NORMAL_PT_UPDATE;
2212 t[0].val = 0;
2213 if (HYPERVISOR_mmu_update(t, 1, &count, DOMID_SELF))
2214 panic("HYPERVISOR_mmu_update() failed");
2215 ASSERT(count == 1);
2216 goto done;
2217 }
2218 #endif /* __xpv */
2219
2220 /*
2221 * Note that the loop is needed to handle changes due to h/w updating
2222 * of PT_MOD/PT_REF.
2223 */
2224 do {
2225 oldpte = GET_PTE(ptep);
2226 if (expect != 0 && (oldpte & PT_PADDR) != (expect & PT_PADDR))
2227 goto done;
2228 XPV_ALLOW_PAGETABLE_UPDATES();
2229 found = CAS_PTE(ptep, oldpte, 0);
2230 XPV_DISALLOW_PAGETABLE_UPDATES();
2231 } while (found != oldpte);
2232 if (oldpte & (PT_REF | PT_MOD))
2233 hat_tlb_inval(ht->ht_hat, htable_e2va(ht, entry));
2234
2235 done:
2236 if (pte_ptr == NULL)
2237 x86pte_release_pagetable(ht);
2238 return (oldpte);
2239 }
2240
2241 /*
2242 * Change a page table entry af it currently matches the value in expect.
2243 */
2244 x86pte_t
2245 x86pte_update(
2246 htable_t *ht,
2247 uint_t entry,
2248 x86pte_t expect,
2249 x86pte_t new)
2250 {
2251 x86pte_t *ptep;
2252 x86pte_t found;
2253
2254 ASSERT(new != 0);
2255 ASSERT(!(ht->ht_flags & HTABLE_SHARED_PFN));
2256 ASSERT(ht->ht_level <= mmu.max_page_level);
2257
2258 ptep = x86pte_access_pagetable(ht, entry);
2259 XPV_ALLOW_PAGETABLE_UPDATES();
2260 found = CAS_PTE(ptep, expect, new);
2261 XPV_DISALLOW_PAGETABLE_UPDATES();
2262 if (found == expect) {
2263 hat_tlb_inval(ht->ht_hat, htable_e2va(ht, entry));
2264
2265 /*
2266 * When removing write permission *and* clearing the
2267 * MOD bit, check if a write happened via a stale
2268 * TLB entry before the TLB shootdown finished.
2269 *
2270 * If it did happen, simply re-enable write permission and
2271 * act like the original CAS failed.
2272 */
2273 if ((expect & (PT_WRITABLE | PT_MOD)) == PT_WRITABLE &&
2274 (new & (PT_WRITABLE | PT_MOD)) == 0 &&
2275 (GET_PTE(ptep) & PT_MOD) != 0) {
2276 do {
2277 found = GET_PTE(ptep);
2278 XPV_ALLOW_PAGETABLE_UPDATES();
2279 found =
2280 CAS_PTE(ptep, found, found | PT_WRITABLE);
2281 XPV_DISALLOW_PAGETABLE_UPDATES();
2282 } while ((found & PT_WRITABLE) == 0);
2283 }
2284 }
2285 x86pte_release_pagetable(ht);
2286 return (found);
2287 }
2288
2289 #ifndef __xpv
2290 /*
2291 * Copy page tables - this is just a little more complicated than the
2292 * previous routines. Note that it's also not atomic! It also is never
2293 * used for VLP pagetables.
2294 */
2295 void
2296 x86pte_copy(htable_t *src, htable_t *dest, uint_t entry, uint_t count)
2297 {
2298 caddr_t src_va;
2299 caddr_t dst_va;
2300 size_t size;
2301 x86pte_t *pteptr;
2302 x86pte_t pte;
2303
2304 ASSERT(khat_running);
2305 ASSERT(!(dest->ht_flags & HTABLE_VLP));
2306 ASSERT(!(src->ht_flags & HTABLE_VLP));
2307 ASSERT(!(src->ht_flags & HTABLE_SHARED_PFN));
2308 ASSERT(!(dest->ht_flags & HTABLE_SHARED_PFN));
2309
2310 /*
2311 * Acquire access to the CPU pagetable windows for the dest and source.
2312 */
2313 dst_va = (caddr_t)x86pte_access_pagetable(dest, entry);
2314 if (kpm_vbase) {
2315 src_va = (caddr_t)
2316 PT_INDEX_PTR(hat_kpm_pfn2va(src->ht_pfn), entry);
2317 } else {
2318 uint_t x = PWIN_SRC(CPU->cpu_id);
2319
2320 /*
2321 * Finish defining the src pagetable mapping
2322 */
2323 src_va = (caddr_t)PT_INDEX_PTR(PWIN_VA(x), entry);
2324 pte = MAKEPTE(src->ht_pfn, 0) | mmu.pt_global | mmu.pt_nx;
2325 pteptr = (x86pte_t *)PWIN_PTE_VA(x);
2326 if (mmu.pae_hat)
2327 *pteptr = pte;
2328 else
2329 *(x86pte32_t *)pteptr = pte;
2330 mmu_tlbflush_entry((caddr_t)(PWIN_VA(x)));
2331 }
2332
2333 /*
2334 * now do the copy
2335 */
2336 size = count << mmu.pte_size_shift;
2337 bcopy(src_va, dst_va, size);
2338
2339 x86pte_release_pagetable(dest);
2340 }
2341
2342 #else /* __xpv */
2343
2344 /*
2345 * The hypervisor only supports writable pagetables at level 0, so we have
2346 * to install these 1 by 1 the slow way.
2347 */
2348 void
2349 x86pte_copy(htable_t *src, htable_t *dest, uint_t entry, uint_t count)
2350 {
2351 caddr_t src_va;
2352 x86pte_t pte;
2353
2354 ASSERT(!IN_XPV_PANIC());
2355 src_va = (caddr_t)x86pte_access_pagetable(src, entry);
2356 while (count) {
2357 if (mmu.pae_hat)
2358 pte = *(x86pte_t *)src_va;
2359 else
2360 pte = *(x86pte32_t *)src_va;
2361 if (pte != 0) {
2362 set_pteval(pfn_to_pa(dest->ht_pfn), entry,
2363 dest->ht_level, pte);
2364 #ifdef __amd64
2365 if (dest->ht_level == mmu.max_level &&
2366 htable_e2va(dest, entry) < HYPERVISOR_VIRT_END)
2367 set_pteval(
2368 pfn_to_pa(dest->ht_hat->hat_user_ptable),
2369 entry, dest->ht_level, pte);
2370 #endif
2371 }
2372 --count;
2373 ++entry;
2374 src_va += mmu.pte_size;
2375 }
2376 x86pte_release_pagetable(src);
2377 }
2378 #endif /* __xpv */
2379
2380 /*
2381 * Zero page table entries - Note this doesn't use atomic stores!
2382 */
2383 static void
2384 x86pte_zero(htable_t *dest, uint_t entry, uint_t count)
2385 {
2386 caddr_t dst_va;
2387 size_t size;
2388 #ifdef __xpv
2389 int x;
2390 x86pte_t newpte;
2391 #endif
2392
2393 /*
2394 * Map in the page table to be zeroed.
2395 */
2396 ASSERT(!(dest->ht_flags & HTABLE_SHARED_PFN));
2397 ASSERT(!(dest->ht_flags & HTABLE_VLP));
2398
2399 /*
2400 * On the hypervisor we don't use x86pte_access_pagetable() since
2401 * in this case the page is not pinned yet.
2402 */
2403 #ifdef __xpv
2404 if (kpm_vbase == NULL) {
2405 kpreempt_disable();
2406 ASSERT(CPU->cpu_hat_info != NULL);
2407 mutex_enter(&CPU->cpu_hat_info->hci_mutex);
2408 x = PWIN_TABLE(CPU->cpu_id);
2409 newpte = MAKEPTE(dest->ht_pfn, 0) | PT_WRITABLE;
2410 xen_map(newpte, PWIN_VA(x));
2411 dst_va = (caddr_t)PT_INDEX_PTR(PWIN_VA(x), entry);
2412 } else
2413 #endif
2414 dst_va = (caddr_t)x86pte_access_pagetable(dest, entry);
2415
2416 size = count << mmu.pte_size_shift;
2417 ASSERT(size > BLOCKZEROALIGN);
2418 #ifdef __i386
2419 if (!is_x86_feature(x86_featureset, X86FSET_SSE2))
2420 bzero(dst_va, size);
2421 else
2422 #endif
2423 block_zero_no_xmm(dst_va, size);
2424
2425 #ifdef __xpv
2426 if (kpm_vbase == NULL) {
2427 xen_map(0, PWIN_VA(x));
2428 mutex_exit(&CPU->cpu_hat_info->hci_mutex);
2429 kpreempt_enable();
2430 } else
2431 #endif
2432 x86pte_release_pagetable(dest);
2433 }
2434
2435 /*
2436 * Called to ensure that all pagetables are in the system dump
2437 */
2438 void
2439 hat_dump(void)
2440 {
2441 hat_t *hat;
2442 uint_t h;
2443 htable_t *ht;
2444
2445 /*
2446 * Dump all page tables
2447 */
2448 for (hat = kas.a_hat; hat != NULL; hat = hat->hat_next) {
2449 for (h = 0; h < hat->hat_num_hash; ++h) {
2450 for (ht = hat->hat_ht_hash[h]; ht; ht = ht->ht_next) {
2451 if ((ht->ht_flags & HTABLE_VLP) == 0)
2452 dump_page(ht->ht_pfn);
2453 }
2454 }
2455 }
2456 }