xref: /titanic_41/usr/src/uts/common/vm/page.h (revision cfb7311ca709ca6f4d930977c7498455556b5312)
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) 1986, 2010, Oracle and/or its affiliates. All rights reserved.
23  */
24 
25 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
26 /*	  All Rights Reserved  	*/
27 
28 /*
29  * University Copyright- Copyright (c) 1982, 1986, 1988
30  * The Regents of the University of California
31  * All Rights Reserved
32  *
33  * University Acknowledgment- Portions of this document are derived from
34  * software developed by the University of California, Berkeley, and its
35  * contributors.
36  */
37 
38 #ifndef	_VM_PAGE_H
39 #define	_VM_PAGE_H
40 
41 #include <vm/seg.h>
42 
43 #ifdef	__cplusplus
44 extern "C" {
45 #endif
46 
47 #if defined(_KERNEL) || defined(_KMEMUSER)
48 
49 /*
50  * Shared/Exclusive lock.
51  */
52 
53 /*
54  * Types of page locking supported by page_lock & friends.
55  */
56 typedef enum {
57 	SE_SHARED,
58 	SE_EXCL			/* exclusive lock (value == -1) */
59 } se_t;
60 
61 /*
62  * For requesting that page_lock reclaim the page from the free list.
63  */
64 typedef enum {
65 	P_RECLAIM,		/* reclaim page from free list */
66 	P_NO_RECLAIM		/* DON`T reclaim the page	*/
67 } reclaim_t;
68 
69 /*
70  * Callers of page_try_reclaim_lock and page_lock_es can use this flag
71  * to get SE_EXCL access before reader/writers are given access.
72  */
73 #define	SE_EXCL_WANTED	0x02
74 
75 /*
76  * All page_*lock() requests will be denied unless this flag is set in
77  * the 'es' parameter.
78  */
79 #define	SE_RETIRED	0x04
80 
81 #endif	/* _KERNEL | _KMEMUSER */
82 
83 typedef int	selock_t;
84 
85 /*
86  * Define VM_STATS to turn on all sorts of statistic gathering about
87  * the VM layer.  By default, it is only turned on when DEBUG is
88  * also defined.
89  */
90 #ifdef DEBUG
91 #define	VM_STATS
92 #endif	/* DEBUG */
93 
94 #ifdef VM_STATS
95 #define	VM_STAT_ADD(stat)			(stat)++
96 #define	VM_STAT_COND_ADD(cond, stat)		((void) (!(cond) || (stat)++))
97 #else
98 #define	VM_STAT_ADD(stat)
99 #define	VM_STAT_COND_ADD(cond, stat)
100 #endif	/* VM_STATS */
101 
102 #ifdef _KERNEL
103 
104 /*
105  * Macros to acquire and release the page logical lock.
106  */
107 #define	page_struct_lock(pp)	mutex_enter(&page_llock)
108 #define	page_struct_unlock(pp)	mutex_exit(&page_llock)
109 
110 #endif	/* _KERNEL */
111 
112 #include <sys/t_lock.h>
113 
114 struct as;
115 
116 /*
117  * Each physical page has a page structure, which is used to maintain
118  * these pages as a cache.  A page can be found via a hashed lookup
119  * based on the [vp, offset].  If a page has an [vp, offset] identity,
120  * then it is entered on a doubly linked circular list off the
121  * vnode using the vpnext/vpprev pointers.   If the p_free bit
122  * is on, then the page is also on a doubly linked circular free
123  * list using next/prev pointers.  If the "p_selock" and "p_iolock"
124  * are held, then the page is currently being read in (exclusive p_selock)
125  * or written back (shared p_selock).  In this case, the next/prev pointers
126  * are used to link the pages together for a consecutive i/o request.  If
127  * the page is being brought in from its backing store, then other processes
128  * will wait for the i/o to complete before attaching to the page since it
129  * will have an "exclusive" lock.
130  *
131  * Each page structure has the locks described below along with
132  * the fields they protect:
133  *
134  *	p_selock	This is a per-page shared/exclusive lock that is
135  *			used to implement the logical shared/exclusive
136  *			lock for each page.  The "shared" lock is normally
137  *			used in most cases while the "exclusive" lock is
138  *			required to destroy or retain exclusive access to
139  *			a page (e.g., while reading in pages).  The appropriate
140  *			lock is always held whenever there is any reference
141  *			to a page structure (e.g., during i/o).
142  *			(Note that with the addition of the "writer-lock-wanted"
143  *			semantics (via SE_EWANTED), threads must not acquire
144  *			multiple reader locks or else a deadly embrace will
145  *			occur in the following situation: thread 1 obtains a
146  *			reader lock; next thread 2 fails to get a writer lock
147  *			but specified SE_EWANTED so it will wait by either
148  *			blocking (when using page_lock_es) or spinning while
149  *			retrying (when using page_try_reclaim_lock) until the
150  *			reader lock is released; then thread 1 attempts to
151  *			get another reader lock but is denied due to
152  *			SE_EWANTED being set, and now both threads are in a
153  *			deadly embrace.)
154  *
155  *				p_hash
156  *				p_vnode
157  *				p_offset
158  *
159  *				p_free
160  *				p_age
161  *
162  *	p_iolock	This is a binary semaphore lock that provides
163  *			exclusive access to the i/o list links in each
164  *			page structure.  It is always held while the page
165  *			is on an i/o list (i.e., involved in i/o).  That is,
166  *			even though a page may be only `shared' locked
167  *			while it is doing a write, the following fields may
168  *			change anyway.  Normally, the page must be
169  *			`exclusively' locked to change anything in it.
170  *
171  *				p_next
172  *				p_prev
173  *
174  * The following fields are protected by the global page_llock:
175  *
176  *				p_lckcnt
177  *				p_cowcnt
178  *
179  * The following lists are protected by the global page_freelock:
180  *
181  *				page_cachelist
182  *				page_freelist
183  *
184  * The following, for our purposes, are protected by
185  * the global freemem_lock:
186  *
187  *				freemem
188  *				freemem_wait
189  *				freemem_cv
190  *
191  * The following fields are protected by hat layer lock(s).  When a page
192  * structure is not mapped and is not associated with a vnode (after a call
193  * to page_hashout() for example) the p_nrm field may be modified with out
194  * holding the hat layer lock:
195  *
196  *				p_nrm
197  *				p_mapping
198  *				p_share
199  *
200  * The following field is file system dependent.  How it is used and
201  * the locking strategies applied are up to the individual file system
202  * implementation.
203  *
204  *				p_fsdata
205  *
206  * The page structure is used to represent and control the system's
207  * physical pages.  There is one instance of the structure for each
208  * page that is not permenately allocated.  For example, the pages that
209  * hold the page structures are permanently held by the kernel
210  * and hence do not need page structures to track them.  The array
211  * of page structures is allocated early on in the kernel's life and
212  * is based on the amount of available physical memory.
213  *
214  * Each page structure may simultaneously appear on several linked lists.
215  * The lists are:  hash list, free or in i/o list, and a vnode's page list.
216  * Each type of list is protected by a different group of mutexes as described
217  * below:
218  *
219  * The hash list is used to quickly find a page when the page's vnode and
220  * offset within the vnode are known.  Each page that is hashed is
221  * connected via the `p_hash' field.  The anchor for each hash is in the
222  * array `page_hash'.  An array of mutexes, `ph_mutex', protects the
223  * lists anchored by page_hash[].  To either search or modify a given hash
224  * list, the appropriate mutex in the ph_mutex array must be held.
225  *
226  * The free list contains pages that are `free to be given away'.  For
227  * efficiency reasons, pages on this list are placed in two catagories:
228  * pages that are still associated with a vnode, and pages that are not
229  * associated with a vnode.  Free pages always have their `p_free' bit set,
230  * free pages that are still associated with a vnode also have their
231  * `p_age' bit set.  Pages on the free list are connected via their
232  * `p_next' and `p_prev' fields.  When a page is involved in some sort
233  * of i/o, it is not free and these fields may be used to link associated
234  * pages together.  At the moment, the free list is protected by a
235  * single mutex `page_freelock'.  The list of free pages still associated
236  * with a vnode is anchored by `page_cachelist' while other free pages
237  * are anchored in architecture dependent ways (to handle page coloring etc.).
238  *
239  * Pages associated with a given vnode appear on a list anchored in the
240  * vnode by the `v_pages' field.  They are linked together with
241  * `p_vpnext' and `p_vpprev'.  The field `p_offset' contains a page's
242  * offset within the vnode.  The pages on this list are not kept in
243  * offset order.  These lists, in a manner similar to the hash lists,
244  * are protected by an array of mutexes called `vph_hash'.  Before
245  * searching or modifying this chain the appropriate mutex in the
246  * vph_hash[] array must be held.
247  *
248  * Again, each of the lists that a page can appear on is protected by a
249  * mutex.  Before reading or writing any of the fields comprising the
250  * list, the appropriate lock must be held.  These list locks should only
251  * be held for very short intervals.
252  *
253  * In addition to the list locks, each page structure contains a
254  * shared/exclusive lock that protects various fields within it.
255  * To modify one of these fields, the `p_selock' must be exclusively held.
256  * To read a field with a degree of certainty, the lock must be at least
257  * held shared.
258  *
259  * Removing a page structure from one of the lists requires holding
260  * the appropriate list lock and the page's p_selock.  A page may be
261  * prevented from changing identity, being freed, or otherwise modified
262  * by acquiring p_selock shared.
263  *
264  * To avoid deadlocks, a strict locking protocol must be followed.  Basically
265  * there are two cases:  In the first case, the page structure in question
266  * is known ahead of time (e.g., when the page is to be added or removed
267  * from a list).  In the second case, the page structure is not known and
268  * must be found by searching one of the lists.
269  *
270  * When adding or removing a known page to one of the lists, first the
271  * page must be exclusively locked (since at least one of its fields
272  * will be modified), second the lock protecting the list must be acquired,
273  * third the page inserted or deleted, and finally the list lock dropped.
274  *
275  * The more interesting case occures when the particular page structure
276  * is not known ahead of time.  For example, when a call is made to
277  * page_lookup(), it is not known if a page with the desired (vnode and
278  * offset pair) identity exists.  So the appropriate mutex in ph_mutex is
279  * acquired, the hash list searched, and if the desired page is found
280  * an attempt is made to lock it.  The attempt to acquire p_selock must
281  * not block while the hash list lock is held.  A deadlock could occure
282  * if some other process was trying to remove the page from the list.
283  * The removing process (following the above protocol) would have exclusively
284  * locked the page, and be spinning waiting to acquire the lock protecting
285  * the hash list.  Since the searching process holds the hash list lock
286  * and is waiting to acquire the page lock, a deadlock occurs.
287  *
288  * The proper scheme to follow is: first, lock the appropriate list,
289  * search the list, and if the desired page is found either use
290  * page_trylock() (which will not block) or pass the address of the
291  * list lock to page_lock().  If page_lock() can not acquire the page's
292  * lock, it will drop the list lock before going to sleep.  page_lock()
293  * returns a value to indicate if the list lock was dropped allowing the
294  * calling program to react appropriately (i.e., retry the operation).
295  *
296  * If the list lock was dropped before the attempt at locking the page
297  * was made, checks would have to be made to ensure that the page had
298  * not changed identity before its lock was obtained.  This is because
299  * the interval between dropping the list lock and acquiring the page
300  * lock is indeterminate.
301  *
302  * In addition, when both a hash list lock (ph_mutex[]) and a vnode list
303  * lock (vph_mutex[]) are needed, the hash list lock must be acquired first.
304  * The routine page_hashin() is a good example of this sequence.
305  * This sequence is ASSERTed by checking that the vph_mutex[] is not held
306  * just before each acquisition of one of the mutexs in ph_mutex[].
307  *
308  * So, as a quick summary:
309  *
310  * 	pse_mutex[]'s protect the p_selock and p_cv fields.
311  *
312  * 	p_selock protects the p_free, p_age, p_vnode, p_offset and p_hash,
313  *
314  * 	ph_mutex[]'s protect the page_hash[] array and its chains.
315  *
316  * 	vph_mutex[]'s protect the v_pages field and the vp page chains.
317  *
318  *	First lock the page, then the hash chain, then the vnode chain.  When
319  *	this is not possible `trylocks' must be used.  Sleeping while holding
320  *	any of these mutexes (p_selock is not a mutex) is not allowed.
321  *
322  *
323  *	field		reading		writing		    ordering
324  *	======================================================================
325  *	p_vnode		p_selock(E,S)	p_selock(E)
326  *	p_offset
327  *	p_free
328  *	p_age
329  *	=====================================================================
330  *	p_hash		p_selock(E,S)	p_selock(E) &&	    p_selock, ph_mutex
331  *					ph_mutex[]
332  *	=====================================================================
333  *	p_vpnext	p_selock(E,S)	p_selock(E) &&	    p_selock, vph_mutex
334  *	p_vpprev			vph_mutex[]
335  *	=====================================================================
336  *	When the p_free bit is set:
337  *
338  *	p_next		p_selock(E,S)	p_selock(E) &&	    p_selock,
339  *	p_prev				page_freelock	    page_freelock
340  *
341  *	When the p_free bit is not set:
342  *
343  *	p_next		p_selock(E,S)	p_selock(E) &&	    p_selock, p_iolock
344  *	p_prev				p_iolock
345  *	=====================================================================
346  *	p_selock	pse_mutex[]	pse_mutex[]	    can`t acquire any
347  *	p_cv						    other mutexes or
348  *							    sleep while holding
349  *							    this lock.
350  *	=====================================================================
351  *	p_lckcnt	p_selock(E,S)	p_selock(E) &&
352  *	p_cowcnt			page_llock
353  *	=====================================================================
354  *	p_nrm		hat layer lock	hat layer lock
355  *	p_mapping
356  *	p_pagenum
357  *	=====================================================================
358  *
359  *	where:
360  *		E----> exclusive version of p_selock.
361  *		S----> shared version of p_selock.
362  *
363  *
364  *	Global data structures and variable:
365  *
366  *	field		reading		writing		    ordering
367  *	=====================================================================
368  *	page_hash[]	ph_mutex[]	ph_mutex[]	    can hold this lock
369  *							    before acquiring
370  *							    a vph_mutex or
371  *							    pse_mutex.
372  *	=====================================================================
373  *	vp->v_pages	vph_mutex[]	vph_mutex[]	    can only acquire
374  *							    a pse_mutex while
375  *							    holding this lock.
376  *	=====================================================================
377  *	page_cachelist	page_freelock	page_freelock	    can't acquire any
378  *	page_freelist	page_freelock	page_freelock
379  *	=====================================================================
380  *	freemem		freemem_lock	freemem_lock	    can't acquire any
381  *	freemem_wait					    other mutexes while
382  *	freemem_cv					    holding this mutex.
383  *	=====================================================================
384  *
385  * Page relocation, PG_NORELOC and P_NORELOC.
386  *
387  * Pages may be relocated using the page_relocate() interface. Relocation
388  * involves moving the contents and identity of a page to another, free page.
389  * To relocate a page, the SE_EXCL lock must be obtained. The way to prevent
390  * a page from being relocated is to hold the SE_SHARED lock (the SE_EXCL
391  * lock must not be held indefinitely). If the page is going to be held
392  * SE_SHARED indefinitely, then the PG_NORELOC hint should be passed
393  * to page_create_va so that pages that are prevented from being relocated
394  * can be managed differently by the platform specific layer.
395  *
396  * Pages locked in memory using page_pp_lock (p_lckcnt/p_cowcnt != 0)
397  * are guaranteed to be held in memory, but can still be relocated
398  * providing the SE_EXCL lock can be obtained.
399  *
400  * The P_NORELOC bit in the page_t.p_state field is provided for use by
401  * the platform specific code in managing pages when the PG_NORELOC
402  * hint is used.
403  *
404  * Memory delete and page locking.
405  *
406  * The set of all usable pages is managed using the global page list as
407  * implemented by the memseg structure defined below. When memory is added
408  * or deleted this list changes. Additions to this list guarantee that the
409  * list is never corrupt.  In order to avoid the necessity of an additional
410  * lock to protect against failed accesses to the memseg being deleted and,
411  * more importantly, the page_ts, the memseg structure is never freed and the
412  * page_t virtual address space is remapped to a page (or pages) of
413  * zeros.  If a page_t is manipulated while it is p_selock'd, or if it is
414  * locked indirectly via a hash or freelist lock, it is not possible for
415  * memory delete to collect the page and so that part of the page list is
416  * prevented from being deleted. If the page is referenced outside of one
417  * of these locks, it is possible for the page_t being referenced to be
418  * deleted.  Examples of this are page_t pointers returned by
419  * page_numtopp_nolock, page_first and page_next.  Providing the page_t
420  * is re-checked after taking the p_selock (for p_vnode != NULL), the
421  * remapping to the zero pages will be detected.
422  *
423  *
424  * Page size (p_szc field) and page locking.
425  *
426  * p_szc field of free pages is changed by free list manager under freelist
427  * locks and is of no concern to the rest of VM subsystem.
428  *
429  * p_szc changes of allocated anonymous (swapfs) can only be done only after
430  * exclusively locking all constituent pages and calling hat_pageunload() on
431  * each of them. To prevent p_szc changes of non free anonymous (swapfs) large
432  * pages it's enough to either lock SHARED any of constituent pages or prevent
433  * hat_pageunload() by holding hat level lock that protects mapping lists (this
434  * method is for hat code only)
435  *
436  * To increase (promote) p_szc of allocated non anonymous file system pages
437  * one has to first lock exclusively all involved constituent pages and call
438  * hat_pageunload() on each of them. To prevent p_szc promote it's enough to
439  * either lock SHARED any of constituent pages that will be needed to make a
440  * large page or prevent hat_pageunload() by holding hat level lock that
441  * protects mapping lists (this method is for hat code only).
442  *
443  * To decrease (demote) p_szc of an allocated non anonymous file system large
444  * page one can either use the same method as used for changeing p_szc of
445  * anonymous large pages or if it's not possible to lock all constituent pages
446  * exclusively a different method can be used. In the second method one only
447  * has to exclusively lock one of constituent pages but then one has to
448  * acquire further locks by calling page_szc_lock() and
449  * hat_page_demote(). hat_page_demote() acquires hat level locks and then
450  * demotes the page. This mechanism relies on the fact that any code that
451  * needs to prevent p_szc of a file system large page from changeing either
452  * locks all constituent large pages at least SHARED or locks some pages at
453  * least SHARED and calls page_szc_lock() or uses hat level page locks.
454  * Demotion using this method is implemented by page_demote_vp_pages().
455  * Please see comments in front of page_demote_vp_pages(), hat_page_demote()
456  * and page_szc_lock() for more details.
457  *
458  * Lock order: p_selock, page_szc_lock, ph_mutex/vph_mutex/freelist,
459  * hat level locks.
460  */
461 
462 typedef struct page {
463 	u_offset_t	p_offset;	/* offset into vnode for this page */
464 	struct vnode	*p_vnode;	/* vnode that this page is named by */
465 	selock_t	p_selock;	/* shared/exclusive lock on the page */
466 #if defined(_LP64)
467 	uint_t		p_vpmref;	/* vpm ref - index of the vpmap_t */
468 #endif
469 	struct page	*p_hash;	/* hash by [vnode, offset] */
470 	struct page	*p_vpnext;	/* next page in vnode list */
471 	struct page	*p_vpprev;	/* prev page in vnode list */
472 	struct page	*p_next;	/* next page in free/intrans lists */
473 	struct page	*p_prev;	/* prev page in free/intrans lists */
474 	ushort_t	p_lckcnt;	/* number of locks on page data */
475 	ushort_t	p_cowcnt;	/* number of copy on write lock */
476 	kcondvar_t	p_cv;		/* page struct's condition var */
477 	kcondvar_t	p_io_cv;	/* for iolock */
478 	uchar_t		p_iolock_state;	/* replaces p_iolock */
479 	volatile uchar_t p_szc;		/* page size code */
480 	uchar_t		p_fsdata;	/* file system dependent byte */
481 	uchar_t		p_state;	/* p_free, p_noreloc */
482 	uchar_t		p_nrm;		/* non-cache, ref, mod readonly bits */
483 #if defined(__sparc)
484 	uchar_t		p_vcolor;	/* virtual color */
485 #else
486 	uchar_t		p_embed;	/* x86 - changes p_mapping & p_index */
487 #endif
488 	uchar_t		p_index;	/* MPSS mapping info. Not used on x86 */
489 	uchar_t		p_toxic;	/* page has an unrecoverable error */
490 	void		*p_mapping;	/* hat specific translation info */
491 	pfn_t		p_pagenum;	/* physical page number */
492 
493 	uint_t		p_share;	/* number of translations */
494 #if defined(_LP64)
495 	uint_t		p_sharepad;	/* pad for growing p_share */
496 #endif
497 	uint_t		p_slckcnt;	/* number of softlocks */
498 #if defined(__sparc)
499 	uint_t		p_kpmref;	/* number of kpm mapping sharers */
500 	struct kpme	*p_kpmelist;	/* kpm specific mapping info */
501 #else
502 	/* index of entry in p_map when p_embed is set */
503 	uint_t		p_mlentry;
504 #endif
505 #if defined(_LP64)
506 	kmutex_t	p_ilock;	/* protects p_vpmref */
507 #else
508 	uint64_t	p_msresv_2;	/* page allocation debugging */
509 #endif
510 } page_t;
511 
512 
513 typedef	page_t	devpage_t;
514 #define	devpage	page
515 
516 #define	PAGE_LOCK_MAXIMUM \
517 	((1 << (sizeof (((page_t *)0)->p_lckcnt) * NBBY)) - 1)
518 
519 #define	PAGE_SLOCK_MAXIMUM UINT_MAX
520 
521 /*
522  * Page hash table is a power-of-two in size, externally chained
523  * through the hash field.  PAGE_HASHAVELEN is the average length
524  * desired for this chain, from which the size of the page_hash
525  * table is derived at boot time and stored in the kernel variable
526  * page_hashsz.  In the hash function it is given by PAGE_HASHSZ.
527  *
528  * PAGE_HASH_FUNC returns an index into the page_hash[] array.  This
529  * index is also used to derive the mutex that protects the chain.
530  *
531  * In constructing the hash function, first we dispose of unimportant bits
532  * (page offset from "off" and the low 3 bits of "vp" which are zero for
533  * struct alignment). Then shift and sum the remaining bits a couple times
534  * in order to get as many source bits from the two source values into the
535  * resulting hashed value.  Note that this will perform quickly, since the
536  * shifting/summing are fast register to register operations with no additional
537  * memory references).
538  */
539 #if defined(_LP64)
540 
541 #if NCPU < 4
542 #define	PH_TABLE_SIZE	128
543 #define	VP_SHIFT	7
544 #else
545 #define	PH_TABLE_SIZE	1024
546 #define	VP_SHIFT	9
547 #endif
548 
549 #else	/* 32 bits */
550 
551 #if NCPU < 4
552 #define	PH_TABLE_SIZE	16
553 #define	VP_SHIFT	7
554 #else
555 #define	PH_TABLE_SIZE	128
556 #define	VP_SHIFT	9
557 #endif
558 
559 #endif	/* _LP64 */
560 
561 /*
562  * The amount to use for the successive shifts in the hash function below.
563  * The actual value is LOG2(PH_TABLE_SIZE), so that as many bits as
564  * possible will filter thru PAGE_HASH_FUNC() and PAGE_HASH_MUTEX().
565  */
566 #define	PH_SHIFT_SIZE   (7)
567 
568 #define	PAGE_HASHSZ	page_hashsz
569 #define	PAGE_HASHAVELEN		4
570 #define	PAGE_HASH_FUNC(vp, off) \
571 	((((uintptr_t)(off) >> PAGESHIFT) + \
572 		((uintptr_t)(off) >> (PAGESHIFT + PH_SHIFT_SIZE)) + \
573 		((uintptr_t)(vp) >> 3) + \
574 		((uintptr_t)(vp) >> (3 + PH_SHIFT_SIZE)) + \
575 		((uintptr_t)(vp) >> (3 + 2 * PH_SHIFT_SIZE))) & \
576 		(PAGE_HASHSZ - 1))
577 #ifdef _KERNEL
578 
579 /*
580  * The page hash value is re-hashed to an index for the ph_mutex array.
581  *
582  * For 64 bit kernels, the mutex array is padded out to prevent false
583  * sharing of cache sub-blocks (64 bytes) of adjacent mutexes.
584  *
585  * For 32 bit kernels, we don't want to waste kernel address space with
586  * padding, so instead we rely on the hash function to introduce skew of
587  * adjacent vnode/offset indexes (the left shift part of the hash function).
588  * Since sizeof (kmutex_t) is 8, we shift an additional 3 to skew to a different
589  * 64 byte sub-block.
590  */
591 typedef struct pad_mutex {
592 	kmutex_t	pad_mutex;
593 #ifdef _LP64
594 	char		pad_pad[64 - sizeof (kmutex_t)];
595 #endif
596 } pad_mutex_t;
597 extern pad_mutex_t ph_mutex[];
598 
599 #define	PAGE_HASH_MUTEX(x) \
600 	&(ph_mutex[((x) + ((x) >> VP_SHIFT) + ((x) << 3)) & \
601 		(PH_TABLE_SIZE - 1)].pad_mutex)
602 
603 /*
604  * Flags used while creating pages.
605  */
606 #define	PG_EXCL		0x0001
607 #define	PG_WAIT		0x0002
608 #define	PG_PHYSCONTIG	0x0004		/* NOT SUPPORTED */
609 #define	PG_MATCH_COLOR	0x0008		/* SUPPORTED by free list routines */
610 #define	PG_NORELOC	0x0010		/* Non-relocatable alloc hint. */
611 					/* Page must be PP_ISNORELOC */
612 #define	PG_PANIC	0x0020		/* system will panic if alloc fails */
613 #define	PG_PUSHPAGE	0x0040		/* alloc may use reserve */
614 #define	PG_LOCAL	0x0080		/* alloc from given lgrp only */
615 
616 /*
617  * When p_selock has the SE_EWANTED bit set, threads waiting for SE_EXCL
618  * access are given priority over all other waiting threads.
619  */
620 #define	SE_EWANTED	0x40000000
621 #define	PAGE_LOCKED(pp)		(((pp)->p_selock & ~SE_EWANTED) != 0)
622 #define	PAGE_SHARED(pp)		(((pp)->p_selock & ~SE_EWANTED) > 0)
623 #define	PAGE_EXCL(pp)		((pp)->p_selock < 0)
624 #define	PAGE_LOCKED_SE(pp, se)	\
625 	((se) == SE_EXCL ? PAGE_EXCL(pp) : PAGE_SHARED(pp))
626 
627 extern	long page_hashsz;
628 extern	page_t **page_hash;
629 
630 extern	kmutex_t page_llock;		/* page logical lock mutex */
631 extern	kmutex_t freemem_lock;		/* freemem lock */
632 
633 extern	pgcnt_t	total_pages;		/* total pages in the system */
634 
635 /*
636  * Variables controlling locking of physical memory.
637  */
638 extern	pgcnt_t	pages_pp_maximum;	/* tuning: lock + claim <= max */
639 extern	void init_pages_pp_maximum(void);
640 
641 struct lgrp;
642 
643 /* page_list_{add,sub} flags */
644 
645 /* which list */
646 #define	PG_FREE_LIST	0x0001
647 #define	PG_CACHE_LIST	0x0002
648 
649 /* where on list */
650 #define	PG_LIST_TAIL	0x0010
651 #define	PG_LIST_HEAD	0x0020
652 
653 /* called from */
654 #define	PG_LIST_ISINIT	0x1000
655 
656 /*
657  * Page frame operations.
658  */
659 page_t	*page_lookup(struct vnode *, u_offset_t, se_t);
660 page_t	*page_lookup_create(struct vnode *, u_offset_t, se_t, page_t *,
661 	spgcnt_t *, int);
662 page_t	*page_lookup_nowait(struct vnode *, u_offset_t, se_t);
663 page_t	*page_find(struct vnode *, u_offset_t);
664 page_t	*page_exists(struct vnode *, u_offset_t);
665 int	page_exists_physcontig(vnode_t *, u_offset_t, uint_t, page_t *[]);
666 int	page_exists_forreal(struct vnode *, u_offset_t, uint_t *);
667 void	page_needfree(spgcnt_t);
668 page_t	*page_create(struct vnode *, u_offset_t, size_t, uint_t);
669 int	page_alloc_pages(struct vnode *, struct seg *, caddr_t, page_t **,
670 	page_t **, uint_t, int, int);
671 page_t  *page_create_va_large(vnode_t *vp, u_offset_t off, size_t bytes,
672 	uint_t flags, struct seg *seg, caddr_t vaddr, void *arg);
673 page_t	*page_create_va(struct vnode *, u_offset_t, size_t, uint_t,
674 	struct seg *, caddr_t);
675 int	page_create_wait(pgcnt_t npages, uint_t flags);
676 void    page_create_putback(spgcnt_t npages);
677 void	page_free(page_t *, int);
678 void	page_free_at_startup(page_t *);
679 void	page_free_pages(page_t *);
680 void	free_vp_pages(struct vnode *, u_offset_t, size_t);
681 int	page_reclaim(page_t *, kmutex_t *);
682 int	page_reclaim_pages(page_t *, kmutex_t *, uint_t);
683 void	page_destroy(page_t *, int);
684 void	page_destroy_pages(page_t *);
685 void	page_destroy_free(page_t *);
686 void	page_rename(page_t *, struct vnode *, u_offset_t);
687 int	page_hashin(page_t *, struct vnode *, u_offset_t, kmutex_t *);
688 void	page_hashout(page_t *, kmutex_t *);
689 int	page_num_hashin(pfn_t, struct vnode *, u_offset_t);
690 void	page_add(page_t **, page_t *);
691 void	page_add_common(page_t **, page_t *);
692 void	page_sub(page_t **, page_t *);
693 void	page_sub_common(page_t **, page_t *);
694 page_t	*page_get_freelist(struct vnode *, u_offset_t, struct seg *,
695 		caddr_t, size_t, uint_t, struct lgrp *);
696 
697 page_t	*page_get_cachelist(struct vnode *, u_offset_t, struct seg *,
698 		caddr_t, uint_t, struct lgrp *);
699 #if defined(__i386) || defined(__amd64)
700 int	page_chk_freelist(uint_t);
701 #endif
702 void	page_list_add(page_t *, int);
703 void	page_boot_demote(page_t *);
704 void	page_promote_size(page_t *, uint_t);
705 void	page_list_add_pages(page_t *, int);
706 void	page_list_sub(page_t *, int);
707 void	page_list_sub_pages(page_t *, uint_t);
708 void	page_list_xfer(page_t *, int, int);
709 void	page_list_break(page_t **, page_t **, size_t);
710 void	page_list_concat(page_t **, page_t **);
711 void	page_vpadd(page_t **, page_t *);
712 void	page_vpsub(page_t **, page_t *);
713 int	page_lock(page_t *, se_t, kmutex_t *, reclaim_t);
714 int	page_lock_es(page_t *, se_t, kmutex_t *, reclaim_t, int);
715 void page_lock_clr_exclwanted(page_t *);
716 int	page_trylock(page_t *, se_t);
717 int	page_try_reclaim_lock(page_t *, se_t, int);
718 int	page_tryupgrade(page_t *);
719 void	page_downgrade(page_t *);
720 void	page_unlock(page_t *);
721 void	page_unlock_nocapture(page_t *);
722 void	page_lock_delete(page_t *);
723 int	page_deleted(page_t *);
724 int	page_pp_lock(page_t *, int, int);
725 void	page_pp_unlock(page_t *, int, int);
726 int	page_resv(pgcnt_t, uint_t);
727 void	page_unresv(pgcnt_t);
728 void	page_pp_useclaim(page_t *, page_t *, uint_t);
729 int	page_addclaim(page_t *);
730 int	page_subclaim(page_t *);
731 int	page_addclaim_pages(page_t **);
732 int	page_subclaim_pages(page_t **);
733 pfn_t	page_pptonum(page_t *);
734 page_t	*page_numtopp(pfn_t, se_t);
735 page_t	*page_numtopp_noreclaim(pfn_t, se_t);
736 page_t	*page_numtopp_nolock(pfn_t);
737 page_t	*page_numtopp_nowait(pfn_t, se_t);
738 page_t  *page_first();
739 page_t  *page_next(page_t *);
740 page_t  *page_list_next(page_t *);
741 page_t	*page_nextn(page_t *, ulong_t);
742 page_t	*page_next_scan_init(void **);
743 page_t	*page_next_scan_large(page_t *, ulong_t *, void **);
744 void    prefetch_page_r(void *);
745 int	ppcopy(page_t *, page_t *);
746 void	page_relocate_hash(page_t *, page_t *);
747 void	pagezero(page_t *, uint_t, uint_t);
748 void	pagescrub(page_t *, uint_t, uint_t);
749 void	page_io_lock(page_t *);
750 void	page_io_unlock(page_t *);
751 int	page_io_trylock(page_t *);
752 int	page_iolock_assert(page_t *);
753 void	page_iolock_init(page_t *);
754 void	page_io_wait(page_t *);
755 int	page_io_locked(page_t *);
756 pgcnt_t	page_busy(int);
757 void	page_lock_init(void);
758 ulong_t	page_share_cnt(page_t *);
759 int	page_isshared(page_t *);
760 int	page_isfree(page_t *);
761 int	page_isref(page_t *);
762 int	page_ismod(page_t *);
763 int	page_release(page_t *, int);
764 void	page_retire_init(void);
765 int	page_retire(uint64_t, uchar_t);
766 int	page_retire_check(uint64_t, uint64_t *);
767 int	page_unretire(uint64_t);
768 int	page_unretire_pp(page_t *, int);
769 void	page_tryretire(page_t *);
770 void	page_retire_mdboot();
771 uint64_t	page_retire_pend_count(void);
772 uint64_t	page_retire_pend_kas_count(void);
773 void	page_retire_incr_pend_count(void *);
774 void	page_retire_decr_pend_count(void *);
775 void	page_clrtoxic(page_t *, uchar_t);
776 void	page_settoxic(page_t *, uchar_t);
777 
778 int	page_mem_avail(pgcnt_t);
779 int	page_reclaim_mem(pgcnt_t, pgcnt_t, int);
780 
781 void page_set_props(page_t *, uint_t);
782 void page_clr_all_props(page_t *);
783 int page_clear_lck_cow(page_t *, int);
784 
785 kmutex_t	*page_vnode_mutex(struct vnode *);
786 kmutex_t	*page_se_mutex(struct page *);
787 kmutex_t	*page_szc_lock(struct page *);
788 int		page_szc_lock_assert(struct page *pp);
789 
790 /*
791  * Page relocation interfaces. page_relocate() is generic.
792  * page_get_replacement_page() is provided by the PSM.
793  * page_free_replacement_page() is generic.
794  */
795 int group_page_trylock(page_t *, se_t);
796 void group_page_unlock(page_t *);
797 int page_relocate(page_t **, page_t **, int, int, spgcnt_t *, struct lgrp *);
798 int do_page_relocate(page_t **, page_t **, int, spgcnt_t *, struct lgrp *);
799 page_t *page_get_replacement_page(page_t *, struct lgrp *, uint_t);
800 void page_free_replacement_page(page_t *);
801 int page_relocate_cage(page_t **, page_t **);
802 
803 int page_try_demote_pages(page_t *);
804 int page_try_demote_free_pages(page_t *);
805 void page_demote_free_pages(page_t *);
806 
807 struct anon_map;
808 
809 void page_mark_migrate(struct seg *, caddr_t, size_t, struct anon_map *,
810     ulong_t, vnode_t *, u_offset_t, int);
811 void page_migrate(struct seg *, caddr_t, page_t **, pgcnt_t);
812 
813 /*
814  * Tell the PIM we are adding physical memory
815  */
816 void add_physmem(page_t *, size_t, pfn_t);
817 void add_physmem_cb(page_t *, pfn_t);	/* callback for page_t part */
818 
819 /*
820  * hw_page_array[] is configured with hardware supported page sizes by
821  * platform specific code.
822  */
823 typedef struct {
824 	size_t	hp_size;
825 	uint_t	hp_shift;
826 	uint_t  hp_colors;
827 	pgcnt_t	hp_pgcnt;	/* base pagesize cnt */
828 } hw_pagesize_t;
829 
830 extern hw_pagesize_t	hw_page_array[];
831 extern uint_t		page_coloring_shift;
832 extern uint_t		page_colors_mask;
833 extern int		cpu_page_colors;
834 extern uint_t		colorequiv;
835 extern uchar_t		colorequivszc[];
836 
837 uint_t	page_num_pagesizes(void);
838 uint_t	page_num_user_pagesizes(int);
839 size_t	page_get_pagesize(uint_t);
840 size_t	page_get_user_pagesize(uint_t n);
841 pgcnt_t	page_get_pagecnt(uint_t);
842 uint_t	page_get_shift(uint_t);
843 int	page_szc(size_t);
844 int	page_szc_user_filtered(size_t);
845 
846 /* page_get_replacement page flags */
847 #define	PGR_SAMESZC	0x1	/* only look for page size same as orig */
848 #define	PGR_NORELOC	0x2	/* allocate a P_NORELOC page */
849 
850 /*
851  * macros for "masked arithmetic"
852  * The purpose is to step through all combinations of a set of bits while
853  * keeping some other bits fixed. Fixed bits need not be contiguous. The
854  * variable bits need not be contiguous either, or even right aligned. The
855  * trick is to set all fixed bits to 1, then increment, then restore the
856  * fixed bits. If incrementing causes a carry from a low bit position, the
857  * carry propagates thru the fixed bits, because they are temporarily set to 1.
858  *	v is the value
859  *	i is the increment
860  *	eq_mask defines the fixed bits
861  *	mask limits the size of the result
862  */
863 #define	ADD_MASKED(v, i, eq_mask, mask) \
864 	(((((v) | (eq_mask)) + (i)) & (mask) & ~(eq_mask)) | ((v) & (eq_mask)))
865 
866 /*
867  * convenience macro which increments by 1
868  */
869 #define	INC_MASKED(v, eq_mask, mask) ADD_MASKED(v, 1, eq_mask, mask)
870 
871 #endif	/* _KERNEL */
872 
873 /*
874  * Constants used for the p_iolock_state
875  */
876 #define	PAGE_IO_INUSE	0x1
877 #define	PAGE_IO_WANTED	0x2
878 
879 /*
880  * Constants used for page_release status
881  */
882 #define	PGREL_NOTREL    0x1
883 #define	PGREL_CLEAN	0x2
884 #define	PGREL_MOD	0x3
885 
886 /*
887  * The p_state field holds what used to be the p_age and p_free
888  * bits.  These fields are protected by p_selock (see above).
889  */
890 #define	P_FREE		0x80		/* Page on free list */
891 #define	P_NORELOC	0x40		/* Page is non-relocatable */
892 #define	P_MIGRATE	0x20		/* Migrate page on next touch */
893 #define	P_SWAP		0x10		/* belongs to vnode that is V_ISSWAP */
894 #define	P_BOOTPAGES	0x08		/* member of bootpages list */
895 #define	P_RAF		0x04		/* page retired at free */
896 
897 #define	PP_ISFREE(pp)		((pp)->p_state & P_FREE)
898 #define	PP_ISAGED(pp)		(((pp)->p_state & P_FREE) && \
899 					((pp)->p_vnode == NULL))
900 #define	PP_ISNORELOC(pp)	((pp)->p_state & P_NORELOC)
901 #define	PP_ISKAS(pp)		(VN_ISKAS((pp)->p_vnode))
902 #define	PP_ISNORELOCKERNEL(pp)	(PP_ISNORELOC(pp) && PP_ISKAS(pp))
903 #define	PP_ISMIGRATE(pp)	((pp)->p_state & P_MIGRATE)
904 #define	PP_ISSWAP(pp)		((pp)->p_state & P_SWAP)
905 #define	PP_ISBOOTPAGES(pp)	((pp)->p_state & P_BOOTPAGES)
906 #define	PP_ISRAF(pp)		((pp)->p_state & P_RAF)
907 
908 #define	PP_SETFREE(pp)		((pp)->p_state = ((pp)->p_state & ~P_MIGRATE) \
909 				| P_FREE)
910 #define	PP_SETAGED(pp)		ASSERT(PP_ISAGED(pp))
911 #define	PP_SETNORELOC(pp)	((pp)->p_state |= P_NORELOC)
912 #define	PP_SETMIGRATE(pp)	((pp)->p_state |= P_MIGRATE)
913 #define	PP_SETSWAP(pp)		((pp)->p_state |= P_SWAP)
914 #define	PP_SETBOOTPAGES(pp)	((pp)->p_state |= P_BOOTPAGES)
915 #define	PP_SETRAF(pp)		((pp)->p_state |= P_RAF)
916 
917 #define	PP_CLRFREE(pp)		((pp)->p_state &= ~P_FREE)
918 #define	PP_CLRAGED(pp)		ASSERT(!PP_ISAGED(pp))
919 #define	PP_CLRNORELOC(pp)	((pp)->p_state &= ~P_NORELOC)
920 #define	PP_CLRMIGRATE(pp)	((pp)->p_state &= ~P_MIGRATE)
921 #define	PP_CLRSWAP(pp)		((pp)->p_state &= ~P_SWAP)
922 #define	PP_CLRBOOTPAGES(pp)	((pp)->p_state &= ~P_BOOTPAGES)
923 #define	PP_CLRRAF(pp)		((pp)->p_state &= ~P_RAF)
924 
925 /*
926  * Flags for page_t p_toxic, for tracking memory hardware errors.
927  *
928  * These flags are OR'ed into p_toxic with page_settoxic() to track which
929  * error(s) have occurred on a given page. The flags are cleared with
930  * page_clrtoxic(). Both page_settoxic() and page_cleartoxic use atomic
931  * primitives to manipulate the p_toxic field so no other locking is needed.
932  *
933  * When an error occurs on a page, p_toxic is set to record the error. The
934  * error could be a memory error or something else (i.e. a datapath). The Page
935  * Retire mechanism does not try to determine the exact cause of the error;
936  * Page Retire rightly leaves that sort of determination to FMA's Diagnostic
937  * Engine (DE).
938  *
939  * Note that, while p_toxic bits can be set without holding any locks, they
940  * should only be cleared while holding the page exclusively locked.
941  * There is one exception to this, the PR_CAPTURE bit is protected by a mutex
942  * within the page capture logic and thus to set or clear the bit, that mutex
943  * needs to be held.  The page does not need to be locked but the page_clrtoxic
944  * function must be used as we need an atomic operation.
945  * Also note that there is what amounts to a hack to prevent recursion with
946  * large pages such that if we are unlocking a page and the PR_CAPTURE bit is
947  * set, we will only try to capture the page if the current threads T_CAPTURING
948  * flag is not set.  If the flag is set, the unlock will not try to capture
949  * the page even though the PR_CAPTURE bit is set.
950  *
951  * Pages with PR_UE or PR_FMA flags are retired unconditionally, while pages
952  * with PR_MCE are retired if the system has not retired too many of them.
953  *
954  * A page must be exclusively locked to be retired. Pages can be retired if
955  * they are mapped, modified, or both, as long as they are not marked PR_UE,
956  * since pages with uncorrectable errors cannot be relocated in memory.
957  * Once a page has been successfully retired it is zeroed, attached to the
958  * retired_pages vnode and, finally, PR_RETIRED is set in p_toxic. The other
959  * p_toxic bits are NOT cleared. Pages are not left locked after retiring them
960  * to avoid special case code throughout the kernel; rather, page_*lock() will
961  * fail to lock the page, unless SE_RETIRED is passed as an argument.
962  *
963  * While we have your attention, go take a look at the comments at the
964  * beginning of page_retire.c too.
965  */
966 #define	PR_OK		0x00	/* no problem */
967 #define	PR_MCE		0x01	/* page has seen two or more CEs */
968 #define	PR_UE		0x02	/* page has an unhandled UE */
969 #define	PR_UE_SCRUBBED	0x04	/* page has seen a UE but was cleaned */
970 #define	PR_FMA		0x08	/* A DE wants this page retired */
971 #define	PR_CAPTURE	0x10	/* Generic page capture flag */
972 #define	PR_RESV		0x20	/* Reserved for future use */
973 #define	PR_MSG		0x40	/* message(s) already printed for this page */
974 #define	PR_RETIRED	0x80	/* This page has been retired */
975 
976 #define	PR_REASONS	(PR_UE | PR_MCE | PR_FMA)
977 #define	PR_TOXIC	(PR_UE)
978 #define	PR_ERRMASK	(PR_UE | PR_UE_SCRUBBED | PR_MCE | PR_FMA)
979 #define	PR_TOXICFLAGS	(0xCF)
980 
981 #define	PP_RETIRED(pp)	((pp)->p_toxic & PR_RETIRED)
982 #define	PP_TOXIC(pp)	((pp)->p_toxic & PR_TOXIC)
983 #define	PP_PR_REQ(pp)	(((pp)->p_toxic & PR_REASONS) && !PP_RETIRED(pp))
984 #define	PP_PR_NOSHARE(pp)						\
985 	((((pp)->p_toxic & (PR_RETIRED | PR_FMA | PR_UE)) == PR_FMA) &&	\
986 	!PP_ISKAS(pp))
987 
988 /*
989  * Flags for page_unretire_pp
990  */
991 #define	PR_UNR_FREE	0x1
992 #define	PR_UNR_CLEAN	0x2
993 #define	PR_UNR_TEMP	0x4
994 
995 /*
996  * kpm large page description.
997  * The virtual address range of segkpm is divided into chunks of
998  * kpm_pgsz. Each chunk is controlled by a kpm_page_t. The ushort
999  * is sufficient for 2^^15 * PAGESIZE, so e.g. the maximum kpm_pgsz
1000  * for 8K is 256M and 2G for 64K pages. It it kept as small as
1001  * possible to save physical memory space.
1002  *
1003  * There are 2 segkpm mapping windows within in the virtual address
1004  * space when we have to prevent VAC alias conflicts. The so called
1005  * Alias window (mappings are always by PAGESIZE) is controlled by
1006  * kp_refcnta. The regular window is controlled by kp_refcnt for the
1007  * normal operation, which is to use the largest available pagesize.
1008  * When VAC alias conflicts are present within a chunk in the regular
1009  * window the large page mapping is broken up into smaller PAGESIZE
1010  * mappings. kp_refcntc is used to control the pages that are invoked
1011  * in the conflict and kp_refcnts holds the active mappings done
1012  * with the small page size. In non vac conflict mode kp_refcntc is
1013  * also used as "go" indication (-1) for the trap level tsbmiss
1014  * handler.
1015  */
1016 typedef struct kpm_page {
1017 	short kp_refcnt;	/* pages mapped large */
1018 	short kp_refcnta;	/* pages mapped in Alias window */
1019 	short kp_refcntc;	/* TL-tsbmiss flag; #vac alias conflict pages */
1020 	short kp_refcnts;	/* vac alias: pages mapped small */
1021 } kpm_page_t;
1022 
1023 /*
1024  * Note: khl_lock offset changes must be reflected in sfmmu_asm.s
1025  */
1026 typedef struct kpm_hlk {
1027 	kmutex_t khl_mutex;	/* kpm_page mutex */
1028 	uint_t   khl_lock;	/* trap level tsbmiss handling */
1029 } kpm_hlk_t;
1030 
1031 /*
1032  * kpm small page description.
1033  * When kpm_pgsz is equal to PAGESIZE a smaller representation is used
1034  * to save memory space. Alias range mappings and regular segkpm
1035  * mappings are done in units of PAGESIZE and can share the mapping
1036  * information and the mappings are always distinguishable by their
1037  * virtual address. Other information needed for VAC conflict prevention
1038  * is already available on a per page basis.
1039  *
1040  * The state about how a kpm page is mapped and whether it is ready to go
1041  * is indicated by the following 1 byte kpm_spage structure. This byte is
1042  * split into two 4-bit parts - kp_mapped and kp_mapped_go.
1043  * 	- kp_mapped == 1	the page is mapped cacheable
1044  *	- kp_mapped == 2	the page is mapped non-cacheable
1045  *	- kp_mapped_go == 1	the mapping is ready to be dropped in
1046  *	- kp_mapped_go == 0	the mapping is not ready to be dropped in.
1047  * When kp_mapped_go == 0, we will have C handler resolve the VAC conflict.
1048  * Otherwise, the assembly tsb miss handler can simply drop in the mapping
1049  * when a tsb miss occurs.
1050  */
1051 typedef union kpm_spage {
1052 	struct {
1053 #ifdef  _BIG_ENDIAN
1054 		uchar_t mapped_go: 4;	/* go or nogo flag */
1055 		uchar_t mapped: 4;	/* page mapped small */
1056 #else
1057 		uchar_t mapped: 4;	/* page mapped small */
1058 		uchar_t mapped_go: 4;	/* go or nogo flag */
1059 #endif
1060 	} kpm_spage_un;
1061 	uchar_t kp_mapped_flag;
1062 } kpm_spage_t;
1063 
1064 #define	kp_mapped	kpm_spage_un.mapped
1065 #define	kp_mapped_go	kpm_spage_un.mapped_go
1066 
1067 /*
1068  * Note: kshl_lock offset changes must be reflected in sfmmu_asm.s
1069  */
1070 typedef struct kpm_shlk {
1071 	uint_t   kshl_lock;	/* trap level tsbmiss handling */
1072 } kpm_shlk_t;
1073 
1074 /*
1075  * Each segment of physical memory is described by a memseg struct.
1076  * Within a segment, memory is considered contiguous. The members
1077  * can be categorized as follows:
1078  * . Platform independent:
1079  *         pages, epages, pages_base, pages_end, next, lnext.
1080  * . 64bit only but platform independent:
1081  *         kpm_pbase, kpm_nkpmpgs, kpm_pages, kpm_spages.
1082  * . Really platform or mmu specific:
1083  *         pagespa, epagespa, nextpa, kpm_pagespa.
1084  * . Mixed:
1085  *         msegflags.
1086  */
1087 struct memseg {
1088 	page_t *pages, *epages;		/* [from, to] in page array */
1089 	pfn_t pages_base, pages_end;	/* [from, to] in page numbers */
1090 	struct memseg *next;		/* next segment in list */
1091 	struct memseg *lnext;		/* next segment in deleted list */
1092 #if defined(__sparc)
1093 	uint64_t pagespa, epagespa;	/* [from, to] page array physical */
1094 	uint64_t nextpa;		/* physical next pointer */
1095 	pfn_t	kpm_pbase;		/* start of kpm range */
1096 	pgcnt_t kpm_nkpmpgs;		/* # of kpm_pgsz pages */
1097 	union _mseg_un {
1098 		kpm_page_t  *kpm_lpgs;	/* ptr to kpm_page array */
1099 		kpm_spage_t *kpm_spgs;	/* ptr to kpm_spage array */
1100 	} mseg_un;
1101 	uint64_t kpm_pagespa;		/* physical ptr to kpm (s)pages array */
1102 #endif /* __sparc */
1103 	uint_t msegflags;		/* memseg flags */
1104 };
1105 
1106 /* memseg union aliases */
1107 #define	kpm_pages	mseg_un.kpm_lpgs
1108 #define	kpm_spages	mseg_un.kpm_spgs
1109 
1110 /* msegflags */
1111 #define	MEMSEG_DYNAMIC		0x1	/* DR: memory was added dynamically */
1112 #define	MEMSEG_META_INCL	0x2	/* DR: memseg includes it's metadata */
1113 #define	MEMSEG_META_ALLOC	0x4	/* DR: memseg allocated it's metadata */
1114 
1115 /* memseg support macros */
1116 #define	MSEG_NPAGES(SEG)	((SEG)->pages_end - (SEG)->pages_base)
1117 
1118 /* memseg hash */
1119 #define	MEM_HASH_SHIFT		0x9
1120 #define	N_MEM_SLOTS		0x200		/* must be a power of 2 */
1121 #define	MEMSEG_PFN_HASH(pfn)	(((pfn)/mhash_per_slot) & (N_MEM_SLOTS - 1))
1122 
1123 /* memseg  externals */
1124 extern struct memseg *memsegs;		/* list of memory segments */
1125 extern ulong_t mhash_per_slot;
1126 extern uint64_t memsegspa;		/* memsegs as physical address */
1127 
1128 void build_pfn_hash();
1129 extern struct memseg *page_numtomemseg_nolock(pfn_t pfnum);
1130 
1131 /*
1132  * page capture related info:
1133  * The page capture routines allow us to asynchronously capture given pages
1134  * for the explicit use of the requestor.  New requestors can be added by
1135  * explicitly adding themselves to the PC_* flags below and incrementing
1136  * PC_NUM_CALLBACKS as necessary.
1137  *
1138  * Subsystems using page capture must register a callback before attempting
1139  * to capture a page.  A duration of -1 will indicate that we will never give
1140  * up while trying to capture a page and will only stop trying to capture the
1141  * given page once we have successfully captured it.  Thus the user needs to be
1142  * aware of the behavior of all callers who have a duration of -1.
1143  *
1144  * For now, only /dev/physmem and page retire use the page capture interface
1145  * and only a single request can be outstanding for a given page.  Thus, if
1146  * /dev/phsymem wants a page and page retire also wants the same page, only
1147  * the page retire request will be honored until the point in time that the
1148  * page is actually retired, at which point in time, subsequent requests by
1149  * /dev/physmem will succeed if the CAPTURE_GET_RETIRED flag was set.
1150  */
1151 
1152 #define	PC_RETIRE		(0)
1153 #define	PC_PHYSMEM		(1)
1154 #define	PC_NUM_CALLBACKS	(2)
1155 #define	PC_MASK			((1 << PC_NUM_CALLBACKS) - 1)
1156 
1157 #define	CAPTURE_RETIRE		(1 << PC_RETIRE)
1158 #define	CAPTURE_PHYSMEM		(1 << PC_PHYSMEM)
1159 
1160 #define	CAPTURE_ASYNC		(0x0200)
1161 
1162 #define	CAPTURE_GET_RETIRED	(0x1000)
1163 #define	CAPTURE_GET_CAGE	(0x2000)
1164 
1165 struct page_capture_callback {
1166 	int cb_active;		/* 1 means active, 0 means inactive */
1167 	clock_t duration;	/* the length in time that we'll attempt to */
1168 				/* capture this page asynchronously. (in HZ) */
1169 	krwlock_t cb_rwlock;
1170 	int (*cb_func)(page_t *, void *, uint_t); /* callback function */
1171 };
1172 
1173 extern kcondvar_t pc_cv;
1174 
1175 void page_capture_register_callback(uint_t index, clock_t duration,
1176     int (*cb_func)(page_t *, void *, uint_t));
1177 void page_capture_unregister_callback(uint_t index);
1178 int page_trycapture(page_t *pp, uint_t szc, uint_t flags, void *datap);
1179 void page_unlock_capture(page_t *pp);
1180 int page_capture_unretire_pp(page_t *);
1181 
1182 extern int memsegs_trylock(int);
1183 extern void memsegs_lock(int);
1184 extern void memsegs_unlock(int);
1185 extern int memsegs_lock_held(void);
1186 extern void memlist_read_lock(void);
1187 extern void memlist_read_unlock(void);
1188 extern void memlist_write_lock(void);
1189 extern void memlist_write_unlock(void);
1190 
1191 #ifdef	__cplusplus
1192 }
1193 #endif
1194 
1195 #endif	/* _VM_PAGE_H */
1196