xref: /illumos-gate/usr/src/uts/common/vm/page.h (revision a3114836)
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 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved  	*/
28 
29 /*
30  * University Copyright- Copyright (c) 1982, 1986, 1988
31  * The Regents of the University of California
32  * All Rights Reserved
33  *
34  * University Acknowledgment- Portions of this document are derived from
35  * software developed by the University of California, Berkeley, and its
36  * contributors.
37  */
38 
39 #ifndef	_VM_PAGE_H
40 #define	_VM_PAGE_H
41 
42 #include <vm/seg.h>
43 
44 #ifdef	__cplusplus
45 extern "C" {
46 #endif
47 
48 #if defined(_KERNEL) || defined(_KMEMUSER)
49 
50 /*
51  * Shared/Exclusive lock.
52  */
53 
54 /*
55  * Types of page locking supported by page_lock & friends.
56  */
57 typedef enum {
58 	SE_SHARED,
59 	SE_EXCL			/* exclusive lock (value == -1) */
60 } se_t;
61 
62 /*
63  * For requesting that page_lock reclaim the page from the free list.
64  */
65 typedef enum {
66 	P_RECLAIM,		/* reclaim page from free list */
67 	P_NO_RECLAIM		/* DON`T reclaim the page	*/
68 } reclaim_t;
69 
70 /*
71  * Callers of page_try_reclaim_lock and page_lock_es can use this flag
72  * to get SE_EXCL access before reader/writers are given access.
73  */
74 #define	SE_EXCL_WANTED	0x02
75 
76 /*
77  * All page_*lock() requests will be denied unless this flag is set in
78  * the 'es' parameter.
79  */
80 #define	SE_RETIRED	0x04
81 
82 #endif	/* _KERNEL | _KMEMUSER */
83 
84 typedef int	selock_t;
85 
86 /*
87  * Define VM_STATS to turn on all sorts of statistic gathering about
88  * the VM layer.  By default, it is only turned on when DEBUG is
89  * also defined.
90  */
91 #ifdef DEBUG
92 #define	VM_STATS
93 #endif	/* DEBUG */
94 
95 #ifdef VM_STATS
96 #define	VM_STAT_ADD(stat)			(stat)++
97 #define	VM_STAT_COND_ADD(cond, stat)		((void) (!(cond) || (stat)++))
98 #else
99 #define	VM_STAT_ADD(stat)
100 #define	VM_STAT_COND_ADD(cond, stat)
101 #endif	/* VM_STATS */
102 
103 #ifdef _KERNEL
104 
105 /*
106  * Macros to acquire and release the page logical lock.
107  */
108 #define	page_struct_lock(pp)	mutex_enter(&page_llock)
109 #define	page_struct_unlock(pp)	mutex_exit(&page_llock)
110 
111 #endif	/* _KERNEL */
112 
113 #include <sys/t_lock.h>
114 
115 struct as;
116 
117 /*
118  * Each physical page has a page structure, which is used to maintain
119  * these pages as a cache.  A page can be found via a hashed lookup
120  * based on the [vp, offset].  If a page has an [vp, offset] identity,
121  * then it is entered on a doubly linked circular list off the
122  * vnode using the vpnext/vpprev pointers.   If the p_free bit
123  * is on, then the page is also on a doubly linked circular free
124  * list using next/prev pointers.  If the "p_selock" and "p_iolock"
125  * are held, then the page is currently being read in (exclusive p_selock)
126  * or written back (shared p_selock).  In this case, the next/prev pointers
127  * are used to link the pages together for a consecutive i/o request.  If
128  * the page is being brought in from its backing store, then other processes
129  * will wait for the i/o to complete before attaching to the page since it
130  * will have an "exclusive" lock.
131  *
132  * Each page structure has the locks described below along with
133  * the fields they protect:
134  *
135  *	p_selock	This is a per-page shared/exclusive lock that is
136  *			used to implement the logical shared/exclusive
137  *			lock for each page.  The "shared" lock is normally
138  *			used in most cases while the "exclusive" lock is
139  *			required to destroy or retain exclusive access to
140  *			a page (e.g., while reading in pages).  The appropriate
141  *			lock is always held whenever there is any reference
142  *			to a page structure (e.g., during i/o).
143  *			(Note that with the addition of the "writer-lock-wanted"
144  *			semantics (via SE_EWANTED), threads must not acquire
145  *			multiple reader locks or else a deadly embrace will
146  *			occur in the following situation: thread 1 obtains a
147  *			reader lock; next thread 2 fails to get a writer lock
148  *			but specified SE_EWANTED so it will wait by either
149  *			blocking (when using page_lock_es) or spinning while
150  *			retrying (when using page_try_reclaim_lock) until the
151  *			reader lock is released; then thread 1 attempts to
152  *			get another reader lock but is denied due to
153  *			SE_EWANTED being set, and now both threads are in a
154  *			deadly embrace.)
155  *
156  *				p_hash
157  *				p_vnode
158  *				p_offset
159  *
160  *				p_free
161  *				p_age
162  *
163  *	p_iolock	This is a binary semaphore lock that provides
164  *			exclusive access to the i/o list links in each
165  *			page structure.  It is always held while the page
166  *			is on an i/o list (i.e., involved in i/o).  That is,
167  *			even though a page may be only `shared' locked
168  *			while it is doing a write, the following fields may
169  *			change anyway.  Normally, the page must be
170  *			`exclusively' locked to change anything in it.
171  *
172  *				p_next
173  *				p_prev
174  *
175  * The following fields are protected by the global page_llock:
176  *
177  *				p_lckcnt
178  *				p_cowcnt
179  *
180  * The following lists are protected by the global page_freelock:
181  *
182  *				page_cachelist
183  *				page_freelist
184  *
185  * The following, for our purposes, are protected by
186  * the global freemem_lock:
187  *
188  *				freemem
189  *				freemem_wait
190  *				freemem_cv
191  *
192  * The following fields are protected by hat layer lock(s).  When a page
193  * structure is not mapped and is not associated with a vnode (after a call
194  * to page_hashout() for example) the p_nrm field may be modified with out
195  * holding the hat layer lock:
196  *
197  *				p_nrm
198  *				p_mapping
199  *				p_share
200  *
201  * The following field is file system dependent.  How it is used and
202  * the locking strategies applied are up to the individual file system
203  * implementation.
204  *
205  *				p_fsdata
206  *
207  * The page structure is used to represent and control the system's
208  * physical pages.  There is one instance of the structure for each
209  * page that is not permenately allocated.  For example, the pages that
210  * hold the page structures are permanently held by the kernel
211  * and hence do not need page structures to track them.  The array
212  * of page structures is allocated early on in the kernel's life and
213  * is based on the amount of available physical memory.
214  *
215  * Each page structure may simultaneously appear on several linked lists.
216  * The lists are:  hash list, free or in i/o list, and a vnode's page list.
217  * Each type of list is protected by a different group of mutexes as described
218  * below:
219  *
220  * The hash list is used to quickly find a page when the page's vnode and
221  * offset within the vnode are known.  Each page that is hashed is
222  * connected via the `p_hash' field.  The anchor for each hash is in the
223  * array `page_hash'.  An array of mutexes, `ph_mutex', protects the
224  * lists anchored by page_hash[].  To either search or modify a given hash
225  * list, the appropriate mutex in the ph_mutex array must be held.
226  *
227  * The free list contains pages that are `free to be given away'.  For
228  * efficiency reasons, pages on this list are placed in two catagories:
229  * pages that are still associated with a vnode, and pages that are not
230  * associated with a vnode.  Free pages always have their `p_free' bit set,
231  * free pages that are still associated with a vnode also have their
232  * `p_age' bit set.  Pages on the free list are connected via their
233  * `p_next' and `p_prev' fields.  When a page is involved in some sort
234  * of i/o, it is not free and these fields may be used to link associated
235  * pages together.  At the moment, the free list is protected by a
236  * single mutex `page_freelock'.  The list of free pages still associated
237  * with a vnode is anchored by `page_cachelist' while other free pages
238  * are anchored in architecture dependent ways (to handle page coloring etc.).
239  *
240  * Pages associated with a given vnode appear on a list anchored in the
241  * vnode by the `v_pages' field.  They are linked together with
242  * `p_vpnext' and `p_vpprev'.  The field `p_offset' contains a page's
243  * offset within the vnode.  The pages on this list are not kept in
244  * offset order.  These lists, in a manner similar to the hash lists,
245  * are protected by an array of mutexes called `vph_hash'.  Before
246  * searching or modifying this chain the appropriate mutex in the
247  * vph_hash[] array must be held.
248  *
249  * Again, each of the lists that a page can appear on is protected by a
250  * mutex.  Before reading or writing any of the fields comprising the
251  * list, the appropriate lock must be held.  These list locks should only
252  * be held for very short intervals.
253  *
254  * In addition to the list locks, each page structure contains a
255  * shared/exclusive lock that protects various fields within it.
256  * To modify one of these fields, the `p_selock' must be exclusively held.
257  * To read a field with a degree of certainty, the lock must be at least
258  * held shared.
259  *
260  * Removing a page structure from one of the lists requires holding
261  * the appropriate list lock and the page's p_selock.  A page may be
262  * prevented from changing identity, being freed, or otherwise modified
263  * by acquiring p_selock shared.
264  *
265  * To avoid deadlocks, a strict locking protocol must be followed.  Basically
266  * there are two cases:  In the first case, the page structure in question
267  * is known ahead of time (e.g., when the page is to be added or removed
268  * from a list).  In the second case, the page structure is not known and
269  * must be found by searching one of the lists.
270  *
271  * When adding or removing a known page to one of the lists, first the
272  * page must be exclusively locked (since at least one of its fields
273  * will be modified), second the lock protecting the list must be acquired,
274  * third the page inserted or deleted, and finally the list lock dropped.
275  *
276  * The more interesting case occures when the particular page structure
277  * is not known ahead of time.  For example, when a call is made to
278  * page_lookup(), it is not known if a page with the desired (vnode and
279  * offset pair) identity exists.  So the appropriate mutex in ph_mutex is
280  * acquired, the hash list searched, and if the desired page is found
281  * an attempt is made to lock it.  The attempt to acquire p_selock must
282  * not block while the hash list lock is held.  A deadlock could occure
283  * if some other process was trying to remove the page from the list.
284  * The removing process (following the above protocol) would have exclusively
285  * locked the page, and be spinning waiting to acquire the lock protecting
286  * the hash list.  Since the searching process holds the hash list lock
287  * and is waiting to acquire the page lock, a deadlock occurs.
288  *
289  * The proper scheme to follow is: first, lock the appropriate list,
290  * search the list, and if the desired page is found either use
291  * page_trylock() (which will not block) or pass the address of the
292  * list lock to page_lock().  If page_lock() can not acquire the page's
293  * lock, it will drop the list lock before going to sleep.  page_lock()
294  * returns a value to indicate if the list lock was dropped allowing the
295  * calling program to react appropriately (i.e., retry the operation).
296  *
297  * If the list lock was dropped before the attempt at locking the page
298  * was made, checks would have to be made to ensure that the page had
299  * not changed identity before its lock was obtained.  This is because
300  * the interval between dropping the list lock and acquiring the page
301  * lock is indeterminate.
302  *
303  * In addition, when both a hash list lock (ph_mutex[]) and a vnode list
304  * lock (vph_mutex[]) are needed, the hash list lock must be acquired first.
305  * The routine page_hashin() is a good example of this sequence.
306  * This sequence is ASSERTed by checking that the vph_mutex[] is not held
307  * just before each acquisition of one of the mutexs in ph_mutex[].
308  *
309  * So, as a quick summary:
310  *
311  * 	pse_mutex[]'s protect the p_selock and p_cv fields.
312  *
313  * 	p_selock protects the p_free, p_age, p_vnode, p_offset and p_hash,
314  *
315  * 	ph_mutex[]'s protect the page_hash[] array and its chains.
316  *
317  * 	vph_mutex[]'s protect the v_pages field and the vp page chains.
318  *
319  *	First lock the page, then the hash chain, then the vnode chain.  When
320  *	this is not possible `trylocks' must be used.  Sleeping while holding
321  *	any of these mutexes (p_selock is not a mutex) is not allowed.
322  *
323  *
324  *	field		reading		writing		    ordering
325  *	======================================================================
326  *	p_vnode		p_selock(E,S)	p_selock(E)
327  *	p_offset
328  *	p_free
329  *	p_age
330  *	=====================================================================
331  *	p_hash		p_selock(E,S)	p_selock(E) &&	    p_selock, ph_mutex
332  *					ph_mutex[]
333  *	=====================================================================
334  *	p_vpnext	p_selock(E,S)	p_selock(E) &&	    p_selock, vph_mutex
335  *	p_vpprev			vph_mutex[]
336  *	=====================================================================
337  *	When the p_free bit is set:
338  *
339  *	p_next		p_selock(E,S)	p_selock(E) &&	    p_selock,
340  *	p_prev				page_freelock	    page_freelock
341  *
342  *	When the p_free bit is not set:
343  *
344  *	p_next		p_selock(E,S)	p_selock(E) &&	    p_selock, p_iolock
345  *	p_prev				p_iolock
346  *	=====================================================================
347  *	p_selock	pse_mutex[]	pse_mutex[]	    can`t acquire any
348  *	p_cv						    other mutexes or
349  *							    sleep while holding
350  *							    this lock.
351  *	=====================================================================
352  *	p_lckcnt	p_selock(E,S)	p_selock(E) &&
353  *	p_cowcnt			page_llock
354  *	=====================================================================
355  *	p_nrm		hat layer lock	hat layer lock
356  *	p_mapping
357  *	p_pagenum
358  *	=====================================================================
359  *
360  *	where:
361  *		E----> exclusive version of p_selock.
362  *		S----> shared version of p_selock.
363  *
364  *
365  *	Global data structures and variable:
366  *
367  *	field		reading		writing		    ordering
368  *	=====================================================================
369  *	page_hash[]	ph_mutex[]	ph_mutex[]	    can hold this lock
370  *							    before acquiring
371  *							    a vph_mutex or
372  *							    pse_mutex.
373  *	=====================================================================
374  *	vp->v_pages	vph_mutex[]	vph_mutex[]	    can only acquire
375  *							    a pse_mutex while
376  *							    holding this lock.
377  *	=====================================================================
378  *	page_cachelist	page_freelock	page_freelock	    can't acquire any
379  *	page_freelist	page_freelock	page_freelock
380  *	=====================================================================
381  *	freemem		freemem_lock	freemem_lock	    can't acquire any
382  *	freemem_wait					    other mutexes while
383  *	freemem_cv					    holding this mutex.
384  *	=====================================================================
385  *
386  * Page relocation, PG_NORELOC and P_NORELOC.
387  *
388  * Pages may be relocated using the page_relocate() interface. Relocation
389  * involves moving the contents and identity of a page to another, free page.
390  * To relocate a page, the SE_EXCL lock must be obtained. The way to prevent
391  * a page from being relocated is to hold the SE_SHARED lock (the SE_EXCL
392  * lock must not be held indefinitely). If the page is going to be held
393  * SE_SHARED indefinitely, then the PG_NORELOC hint should be passed
394  * to page_create_va so that pages that are prevented from being relocated
395  * can be managed differently by the platform specific layer.
396  *
397  * Pages locked in memory using page_pp_lock (p_lckcnt/p_cowcnt != 0)
398  * are guaranteed to be held in memory, but can still be relocated
399  * providing the SE_EXCL lock can be obtained.
400  *
401  * The P_NORELOC bit in the page_t.p_state field is provided for use by
402  * the platform specific code in managing pages when the PG_NORELOC
403  * hint is used.
404  *
405  * Memory delete and page locking.
406  *
407  * The set of all usable pages is managed using the global page list as
408  * implemented by the memseg structure defined below. When memory is added
409  * or deleted this list changes. Additions to this list guarantee that the
410  * list is never corrupt.  In order to avoid the necessity of an additional
411  * lock to protect against failed accesses to the memseg being deleted and,
412  * more importantly, the page_ts, the memseg structure is never freed and the
413  * page_t virtual address space is remapped to a page (or pages) of
414  * zeros.  If a page_t is manipulated while it is p_selock'd, or if it is
415  * locked indirectly via a hash or freelist lock, it is not possible for
416  * memory delete to collect the page and so that part of the page list is
417  * prevented from being deleted. If the page is referenced outside of one
418  * of these locks, it is possible for the page_t being referenced to be
419  * deleted.  Examples of this are page_t pointers returned by
420  * page_numtopp_nolock, page_first and page_next.  Providing the page_t
421  * is re-checked after taking the p_selock (for p_vnode != NULL), the
422  * remapping to the zero pages will be detected.
423  *
424  *
425  * Page size (p_szc field) and page locking.
426  *
427  * p_szc field of free pages is changed by free list manager under freelist
428  * locks and is of no concern to the rest of VM subsystem.
429  *
430  * p_szc changes of allocated anonymous (swapfs) can only be done only after
431  * exclusively locking all constituent pages and calling hat_pageunload() on
432  * each of them. To prevent p_szc changes of non free anonymous (swapfs) large
433  * pages it's enough to either lock SHARED any of constituent pages or prevent
434  * hat_pageunload() by holding hat level lock that protects mapping lists (this
435  * method is for hat code only)
436  *
437  * To increase (promote) p_szc of allocated non anonymous file system pages
438  * one has to first lock exclusively all involved constituent pages and call
439  * hat_pageunload() on each of them. To prevent p_szc promote it's enough to
440  * either lock SHARED any of constituent pages that will be needed to make a
441  * large page or prevent hat_pageunload() by holding hat level lock that
442  * protects mapping lists (this method is for hat code only).
443  *
444  * To decrease (demote) p_szc of an allocated non anonymous file system large
445  * page one can either use the same method as used for changeing p_szc of
446  * anonymous large pages or if it's not possible to lock all constituent pages
447  * exclusively a different method can be used. In the second method one only
448  * has to exclusively lock one of constituent pages but then one has to
449  * acquire further locks by calling page_szc_lock() and
450  * hat_page_demote(). hat_page_demote() acquires hat level locks and then
451  * demotes the page. This mechanism relies on the fact that any code that
452  * needs to prevent p_szc of a file system large page from changeing either
453  * locks all constituent large pages at least SHARED or locks some pages at
454  * least SHARED and calls page_szc_lock() or uses hat level page locks.
455  * Demotion using this method is implemented by page_demote_vp_pages().
456  * Please see comments in front of page_demote_vp_pages(), hat_page_demote()
457  * and page_szc_lock() for more details.
458  *
459  * Lock order: p_selock, page_szc_lock, ph_mutex/vph_mutex/freelist,
460  * hat level locks.
461  */
462 
463 typedef struct page {
464 	u_offset_t	p_offset;	/* offset into vnode for this page */
465 	struct vnode	*p_vnode;	/* vnode that this page is named by */
466 	selock_t	p_selock;	/* shared/exclusive lock on the page */
467 #if defined(_LP64)
468 	uint_t		p_vpmref;	/* vpm ref - index of the vpmap_t */
469 #endif
470 	struct page	*p_hash;	/* hash by [vnode, offset] */
471 	struct page	*p_vpnext;	/* next page in vnode list */
472 	struct page	*p_vpprev;	/* prev page in vnode list */
473 	struct page	*p_next;	/* next page in free/intrans lists */
474 	struct page	*p_prev;	/* prev page in free/intrans lists */
475 	ushort_t	p_lckcnt;	/* number of locks on page data */
476 	ushort_t	p_cowcnt;	/* number of copy on write lock */
477 	kcondvar_t	p_cv;		/* page struct's condition var */
478 	kcondvar_t	p_io_cv;	/* for iolock */
479 	uchar_t		p_iolock_state;	/* replaces p_iolock */
480 	volatile uchar_t p_szc;		/* page size code */
481 	uchar_t		p_fsdata;	/* file system dependent byte */
482 	uchar_t		p_state;	/* p_free, p_noreloc */
483 	uchar_t		p_nrm;		/* non-cache, ref, mod readonly bits */
484 #if defined(__sparc)
485 	uchar_t		p_vcolor;	/* virtual color */
486 #else
487 	uchar_t		p_embed;	/* x86 - changes p_mapping & p_index */
488 #endif
489 	uchar_t		p_index;	/* MPSS mapping info. Not used on x86 */
490 	uchar_t		p_toxic;	/* page has an unrecoverable error */
491 	void		*p_mapping;	/* hat specific translation info */
492 	pfn_t		p_pagenum;	/* physical page number */
493 
494 	uint_t		p_share;	/* number of translations */
495 #if defined(_LP64)
496 	uint_t		p_sharepad;	/* pad for growing p_share */
497 #endif
498 	uint_t		p_slckcnt;	/* number of softlocks */
499 #if defined(__sparc)
500 	uint_t		p_kpmref;	/* number of kpm mapping sharers */
501 	struct kpme	*p_kpmelist;	/* kpm specific mapping info */
502 #else
503 	/* index of entry in p_map when p_embed is set */
504 	uint_t		p_mlentry;
505 #endif
506 #if defined(_LP64)
507 	kmutex_t	p_ilock;	/* protects p_vpmref */
508 #else
509 	uint64_t	p_msresv_2;	/* page allocation debugging */
510 #endif
511 } page_t;
512 
513 
514 typedef	page_t	devpage_t;
515 #define	devpage	page
516 
517 #define	PAGE_LOCK_MAXIMUM \
518 	((1 << (sizeof (((page_t *)0)->p_lckcnt) * NBBY)) - 1)
519 
520 #define	PAGE_SLOCK_MAXIMUM UINT_MAX
521 
522 /*
523  * Page hash table is a power-of-two in size, externally chained
524  * through the hash field.  PAGE_HASHAVELEN is the average length
525  * desired for this chain, from which the size of the page_hash
526  * table is derived at boot time and stored in the kernel variable
527  * page_hashsz.  In the hash function it is given by PAGE_HASHSZ.
528  *
529  * PAGE_HASH_FUNC returns an index into the page_hash[] array.  This
530  * index is also used to derive the mutex that protects the chain.
531  *
532  * In constructing the hash function, first we dispose of unimportant bits
533  * (page offset from "off" and the low 3 bits of "vp" which are zero for
534  * struct alignment). Then shift and sum the remaining bits a couple times
535  * in order to get as many source bits from the two source values into the
536  * resulting hashed value.  Note that this will perform quickly, since the
537  * shifting/summing are fast register to register operations with no additional
538  * memory references).
539  */
540 #if defined(_LP64)
541 
542 #if NCPU < 4
543 #define	PH_TABLE_SIZE	128
544 #define	VP_SHIFT	7
545 #else
546 #define	PH_TABLE_SIZE	1024
547 #define	VP_SHIFT	9
548 #endif
549 
550 #else	/* 32 bits */
551 
552 #if NCPU < 4
553 #define	PH_TABLE_SIZE	16
554 #define	VP_SHIFT	7
555 #else
556 #define	PH_TABLE_SIZE	128
557 #define	VP_SHIFT	9
558 #endif
559 
560 #endif	/* _LP64 */
561 
562 /*
563  * The amount to use for the successive shifts in the hash function below.
564  * The actual value is LOG2(PH_TABLE_SIZE), so that as many bits as
565  * possible will filter thru PAGE_HASH_FUNC() and PAGE_HASH_MUTEX().
566  */
567 #define	PH_SHIFT_SIZE   (7)
568 
569 #define	PAGE_HASHSZ	page_hashsz
570 #define	PAGE_HASHAVELEN		4
571 #define	PAGE_HASH_FUNC(vp, off) \
572 	((((uintptr_t)(off) >> PAGESHIFT) + \
573 		((uintptr_t)(off) >> (PAGESHIFT + PH_SHIFT_SIZE)) + \
574 		((uintptr_t)(vp) >> 3) + \
575 		((uintptr_t)(vp) >> (3 + PH_SHIFT_SIZE)) + \
576 		((uintptr_t)(vp) >> (3 + 2 * PH_SHIFT_SIZE))) & \
577 		(PAGE_HASHSZ - 1))
578 #ifdef _KERNEL
579 
580 /*
581  * The page hash value is re-hashed to an index for the ph_mutex array.
582  *
583  * For 64 bit kernels, the mutex array is padded out to prevent false
584  * sharing of cache sub-blocks (64 bytes) of adjacent mutexes.
585  *
586  * For 32 bit kernels, we don't want to waste kernel address space with
587  * padding, so instead we rely on the hash function to introduce skew of
588  * adjacent vnode/offset indexes (the left shift part of the hash function).
589  * Since sizeof (kmutex_t) is 8, we shift an additional 3 to skew to a different
590  * 64 byte sub-block.
591  */
592 typedef struct pad_mutex {
593 	kmutex_t	pad_mutex;
594 #ifdef _LP64
595 	char		pad_pad[64 - sizeof (kmutex_t)];
596 #endif
597 } pad_mutex_t;
598 extern pad_mutex_t ph_mutex[];
599 
600 #define	PAGE_HASH_MUTEX(x) \
601 	&(ph_mutex[((x) + ((x) >> VP_SHIFT) + ((x) << 3)) & \
602 		(PH_TABLE_SIZE - 1)].pad_mutex)
603 
604 /*
605  * Flags used while creating pages.
606  */
607 #define	PG_EXCL		0x0001
608 #define	PG_WAIT		0x0002
609 #define	PG_PHYSCONTIG	0x0004		/* NOT SUPPORTED */
610 #define	PG_MATCH_COLOR	0x0008		/* SUPPORTED by free list routines */
611 #define	PG_NORELOC	0x0010		/* Non-relocatable alloc hint. */
612 					/* Page must be PP_ISNORELOC */
613 #define	PG_PANIC	0x0020		/* system will panic if alloc fails */
614 #define	PG_PUSHPAGE	0x0040		/* alloc may use reserve */
615 #define	PG_LOCAL	0x0080		/* alloc from given lgrp only */
616 
617 /*
618  * When p_selock has the SE_EWANTED bit set, threads waiting for SE_EXCL
619  * access are given priority over all other waiting threads.
620  */
621 #define	SE_EWANTED	0x40000000
622 #define	PAGE_LOCKED(pp)		(((pp)->p_selock & ~SE_EWANTED) != 0)
623 #define	PAGE_SHARED(pp)		(((pp)->p_selock & ~SE_EWANTED) > 0)
624 #define	PAGE_EXCL(pp)		((pp)->p_selock < 0)
625 #define	PAGE_LOCKED_SE(pp, se)	\
626 	((se) == SE_EXCL ? PAGE_EXCL(pp) : PAGE_SHARED(pp))
627 
628 extern	long page_hashsz;
629 extern	page_t **page_hash;
630 
631 extern	kmutex_t page_llock;		/* page logical lock mutex */
632 extern	kmutex_t freemem_lock;		/* freemem lock */
633 
634 extern	pgcnt_t	total_pages;		/* total pages in the system */
635 
636 /*
637  * Variables controlling locking of physical memory.
638  */
639 extern	pgcnt_t	pages_pp_maximum;	/* tuning: lock + claim <= max */
640 extern	void init_pages_pp_maximum(void);
641 
642 struct lgrp;
643 
644 /* page_list_{add,sub} flags */
645 
646 /* which list */
647 #define	PG_FREE_LIST	0x0001
648 #define	PG_CACHE_LIST	0x0002
649 
650 /* where on list */
651 #define	PG_LIST_TAIL	0x0010
652 #define	PG_LIST_HEAD	0x0020
653 
654 /* called from */
655 #define	PG_LIST_ISINIT	0x1000
656 
657 /*
658  * Page frame operations.
659  */
660 page_t	*page_lookup(struct vnode *, u_offset_t, se_t);
661 page_t	*page_lookup_create(struct vnode *, u_offset_t, se_t, page_t *,
662 	spgcnt_t *, int);
663 page_t	*page_lookup_nowait(struct vnode *, u_offset_t, se_t);
664 page_t	*page_find(struct vnode *, u_offset_t);
665 page_t	*page_exists(struct vnode *, u_offset_t);
666 int	page_exists_physcontig(vnode_t *, u_offset_t, uint_t, page_t *[]);
667 int	page_exists_forreal(struct vnode *, u_offset_t, uint_t *);
668 void	page_needfree(spgcnt_t);
669 page_t	*page_create(struct vnode *, u_offset_t, size_t, uint_t);
670 int	page_alloc_pages(struct vnode *, struct seg *, caddr_t, page_t **,
671 	page_t **, uint_t, int, int);
672 page_t  *page_create_va_large(vnode_t *vp, u_offset_t off, size_t bytes,
673 	uint_t flags, struct seg *seg, caddr_t vaddr, void *arg);
674 page_t	*page_create_va(struct vnode *, u_offset_t, size_t, uint_t,
675 	struct seg *, caddr_t);
676 int	page_create_wait(pgcnt_t npages, uint_t flags);
677 void    page_create_putback(spgcnt_t npages);
678 void	page_free(page_t *, int);
679 void	page_free_at_startup(page_t *);
680 void	page_free_pages(page_t *);
681 void	free_vp_pages(struct vnode *, u_offset_t, size_t);
682 int	page_reclaim(page_t *, kmutex_t *);
683 int	page_reclaim_pages(page_t *, kmutex_t *, uint_t);
684 void	page_destroy(page_t *, int);
685 void	page_destroy_pages(page_t *);
686 void	page_destroy_free(page_t *);
687 void	page_rename(page_t *, struct vnode *, u_offset_t);
688 int	page_hashin(page_t *, struct vnode *, u_offset_t, kmutex_t *);
689 void	page_hashout(page_t *, kmutex_t *);
690 int	page_num_hashin(pfn_t, struct vnode *, u_offset_t);
691 void	page_add(page_t **, page_t *);
692 void	page_add_common(page_t **, page_t *);
693 void	page_sub(page_t **, page_t *);
694 void	page_sub_common(page_t **, page_t *);
695 page_t	*page_get_freelist(struct vnode *, u_offset_t, struct seg *,
696 		caddr_t, size_t, uint_t, struct lgrp *);
697 
698 page_t	*page_get_cachelist(struct vnode *, u_offset_t, struct seg *,
699 		caddr_t, uint_t, struct lgrp *);
700 #if defined(__i386) || defined(__amd64)
701 int	page_chk_freelist(uint_t);
702 #endif
703 void	page_list_add(page_t *, int);
704 void	page_boot_demote(page_t *);
705 void	page_promote_size(page_t *, uint_t);
706 void	page_list_add_pages(page_t *, int);
707 void	page_list_sub(page_t *, int);
708 void	page_list_sub_pages(page_t *, uint_t);
709 void	page_list_xfer(page_t *, int, int);
710 void	page_list_break(page_t **, page_t **, size_t);
711 void	page_list_concat(page_t **, page_t **);
712 void	page_vpadd(page_t **, page_t *);
713 void	page_vpsub(page_t **, page_t *);
714 int	page_lock(page_t *, se_t, kmutex_t *, reclaim_t);
715 int	page_lock_es(page_t *, se_t, kmutex_t *, reclaim_t, int);
716 void page_lock_clr_exclwanted(page_t *);
717 int	page_trylock(page_t *, se_t);
718 int	page_try_reclaim_lock(page_t *, se_t, int);
719 int	page_tryupgrade(page_t *);
720 void	page_downgrade(page_t *);
721 void	page_unlock(page_t *);
722 void	page_unlock_nocapture(page_t *);
723 void	page_lock_delete(page_t *);
724 int	page_deleted(page_t *);
725 int	page_pp_lock(page_t *, int, int);
726 void	page_pp_unlock(page_t *, int, int);
727 int	page_resv(pgcnt_t, uint_t);
728 void	page_unresv(pgcnt_t);
729 void	page_pp_useclaim(page_t *, page_t *, uint_t);
730 int	page_addclaim(page_t *);
731 int	page_subclaim(page_t *);
732 int	page_addclaim_pages(page_t **);
733 int	page_subclaim_pages(page_t **);
734 pfn_t	page_pptonum(page_t *);
735 page_t	*page_numtopp(pfn_t, se_t);
736 page_t	*page_numtopp_noreclaim(pfn_t, se_t);
737 page_t	*page_numtopp_nolock(pfn_t);
738 page_t	*page_numtopp_nowait(pfn_t, se_t);
739 page_t  *page_first();
740 page_t  *page_next(page_t *);
741 page_t  *page_list_next(page_t *);
742 page_t	*page_nextn(page_t *, ulong_t);
743 page_t	*page_next_scan_init(void **);
744 page_t	*page_next_scan_large(page_t *, ulong_t *, void **);
745 void    prefetch_page_r(void *);
746 int	ppcopy(page_t *, page_t *);
747 void	page_relocate_hash(page_t *, page_t *);
748 void	pagezero(page_t *, uint_t, uint_t);
749 void	pagescrub(page_t *, uint_t, uint_t);
750 void	page_io_lock(page_t *);
751 void	page_io_unlock(page_t *);
752 int	page_io_trylock(page_t *);
753 int	page_iolock_assert(page_t *);
754 void	page_iolock_init(page_t *);
755 void	page_io_wait(page_t *);
756 int	page_io_locked(page_t *);
757 pgcnt_t	page_busy(int);
758 void	page_lock_init(void);
759 ulong_t	page_share_cnt(page_t *);
760 int	page_isshared(page_t *);
761 int	page_isfree(page_t *);
762 int	page_isref(page_t *);
763 int	page_ismod(page_t *);
764 int	page_release(page_t *, int);
765 void	page_retire_init(void);
766 int	page_retire(uint64_t, uchar_t);
767 int	page_retire_check(uint64_t, uint64_t *);
768 int	page_unretire(uint64_t);
769 int	page_unretire_pp(page_t *, int);
770 void	page_tryretire(page_t *);
771 void	page_retire_mdboot();
772 uint64_t	page_retire_pend_count(void);
773 uint64_t	page_retire_pend_kas_count(void);
774 void	page_retire_incr_pend_count(void *);
775 void	page_retire_decr_pend_count(void *);
776 void	page_clrtoxic(page_t *, uchar_t);
777 void	page_settoxic(page_t *, uchar_t);
778 
779 int	page_mem_avail(pgcnt_t);
780 int	page_reclaim_mem(pgcnt_t, pgcnt_t, int);
781 
782 void page_set_props(page_t *, uint_t);
783 void page_clr_all_props(page_t *);
784 int page_clear_lck_cow(page_t *, int);
785 
786 kmutex_t	*page_vnode_mutex(struct vnode *);
787 kmutex_t	*page_se_mutex(struct page *);
788 kmutex_t	*page_szc_lock(struct page *);
789 int		page_szc_lock_assert(struct page *pp);
790 
791 /*
792  * Page relocation interfaces. page_relocate() is generic.
793  * page_get_replacement_page() is provided by the PSM.
794  * page_free_replacement_page() is generic.
795  */
796 int group_page_trylock(page_t *, se_t);
797 void group_page_unlock(page_t *);
798 int page_relocate(page_t **, page_t **, int, int, spgcnt_t *, struct lgrp *);
799 int do_page_relocate(page_t **, page_t **, int, spgcnt_t *, struct lgrp *);
800 page_t *page_get_replacement_page(page_t *, struct lgrp *, uint_t);
801 void page_free_replacement_page(page_t *);
802 int page_relocate_cage(page_t **, page_t **);
803 
804 int page_try_demote_pages(page_t *);
805 int page_try_demote_free_pages(page_t *);
806 void page_demote_free_pages(page_t *);
807 
808 struct anon_map;
809 
810 void page_mark_migrate(struct seg *, caddr_t, size_t, struct anon_map *,
811     ulong_t, vnode_t *, u_offset_t, int);
812 void page_migrate(struct seg *, caddr_t, page_t **, pgcnt_t);
813 
814 /*
815  * Tell the PIM we are adding physical memory
816  */
817 void add_physmem(page_t *, size_t, pfn_t);
818 void add_physmem_cb(page_t *, pfn_t);	/* callback for page_t part */
819 
820 /*
821  * hw_page_array[] is configured with hardware supported page sizes by
822  * platform specific code.
823  */
824 typedef struct {
825 	size_t	hp_size;
826 	uint_t	hp_shift;
827 	uint_t  hp_colors;
828 	pgcnt_t	hp_pgcnt;	/* base pagesize cnt */
829 } hw_pagesize_t;
830 
831 extern hw_pagesize_t	hw_page_array[];
832 extern uint_t		page_coloring_shift;
833 extern uint_t		page_colors_mask;
834 extern int		cpu_page_colors;
835 extern uint_t		colorequiv;
836 extern uchar_t		colorequivszc[];
837 
838 uint_t	page_num_pagesizes(void);
839 uint_t	page_num_user_pagesizes(int);
840 size_t	page_get_pagesize(uint_t);
841 size_t	page_get_user_pagesize(uint_t n);
842 pgcnt_t	page_get_pagecnt(uint_t);
843 uint_t	page_get_shift(uint_t);
844 int	page_szc(size_t);
845 int	page_szc_user_filtered(size_t);
846 
847 /* page_get_replacement page flags */
848 #define	PGR_SAMESZC	0x1	/* only look for page size same as orig */
849 #define	PGR_NORELOC	0x2	/* allocate a P_NORELOC page */
850 
851 /*
852  * macros for "masked arithmetic"
853  * The purpose is to step through all combinations of a set of bits while
854  * keeping some other bits fixed. Fixed bits need not be contiguous. The
855  * variable bits need not be contiguous either, or even right aligned. The
856  * trick is to set all fixed bits to 1, then increment, then restore the
857  * fixed bits. If incrementing causes a carry from a low bit position, the
858  * carry propagates thru the fixed bits, because they are temporarily set to 1.
859  *	v is the value
860  *	i is the increment
861  *	eq_mask defines the fixed bits
862  *	mask limits the size of the result
863  */
864 #define	ADD_MASKED(v, i, eq_mask, mask) \
865 	(((((v) | (eq_mask)) + (i)) & (mask) & ~(eq_mask)) | ((v) & (eq_mask)))
866 
867 /*
868  * convenience macro which increments by 1
869  */
870 #define	INC_MASKED(v, eq_mask, mask) ADD_MASKED(v, 1, eq_mask, mask)
871 
872 #endif	/* _KERNEL */
873 
874 /*
875  * Constants used for the p_iolock_state
876  */
877 #define	PAGE_IO_INUSE	0x1
878 #define	PAGE_IO_WANTED	0x2
879 
880 /*
881  * Constants used for page_release status
882  */
883 #define	PGREL_NOTREL    0x1
884 #define	PGREL_CLEAN	0x2
885 #define	PGREL_MOD	0x3
886 
887 /*
888  * The p_state field holds what used to be the p_age and p_free
889  * bits.  These fields are protected by p_selock (see above).
890  */
891 #define	P_FREE		0x80		/* Page on free list */
892 #define	P_NORELOC	0x40		/* Page is non-relocatable */
893 #define	P_MIGRATE	0x20		/* Migrate page on next touch */
894 #define	P_SWAP		0x10		/* belongs to vnode that is V_ISSWAP */
895 #define	P_BOOTPAGES	0x08		/* member of bootpages list */
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 
907 #define	PP_SETFREE(pp)		((pp)->p_state = ((pp)->p_state & ~P_MIGRATE) \
908 				| P_FREE)
909 #define	PP_SETAGED(pp)		ASSERT(PP_ISAGED(pp))
910 #define	PP_SETNORELOC(pp)	((pp)->p_state |= P_NORELOC)
911 #define	PP_SETMIGRATE(pp)	((pp)->p_state |= P_MIGRATE)
912 #define	PP_SETSWAP(pp)		((pp)->p_state |= P_SWAP)
913 #define	PP_SETBOOTPAGES(pp)	((pp)->p_state |= P_BOOTPAGES)
914 
915 #define	PP_CLRFREE(pp)		((pp)->p_state &= ~P_FREE)
916 #define	PP_CLRAGED(pp)		ASSERT(!PP_ISAGED(pp))
917 #define	PP_CLRNORELOC(pp)	((pp)->p_state &= ~P_NORELOC)
918 #define	PP_CLRMIGRATE(pp)	((pp)->p_state &= ~P_MIGRATE)
919 #define	PP_CLRSWAP(pp)		((pp)->p_state &= ~P_SWAP)
920 #define	PP_CLRBOOTPAGES(pp)	((pp)->p_state &= ~P_BOOTPAGES)
921 
922 /*
923  * Flags for page_t p_toxic, for tracking memory hardware errors.
924  *
925  * These flags are OR'ed into p_toxic with page_settoxic() to track which
926  * error(s) have occurred on a given page. The flags are cleared with
927  * page_clrtoxic(). Both page_settoxic() and page_cleartoxic use atomic
928  * primitives to manipulate the p_toxic field so no other locking is needed.
929  *
930  * When an error occurs on a page, p_toxic is set to record the error. The
931  * error could be a memory error or something else (i.e. a datapath). The Page
932  * Retire mechanism does not try to determine the exact cause of the error;
933  * Page Retire rightly leaves that sort of determination to FMA's Diagnostic
934  * Engine (DE).
935  *
936  * Note that, while p_toxic bits can be set without holding any locks, they
937  * should only be cleared while holding the page exclusively locked.
938  * There is one exception to this, the PR_CAPTURE bit is protected by a mutex
939  * within the page capture logic and thus to set or clear the bit, that mutex
940  * needs to be held.  The page does not need to be locked but the page_clrtoxic
941  * function must be used as we need an atomic operation.
942  * Also note that there is what amounts to a hack to prevent recursion with
943  * large pages such that if we are unlocking a page and the PR_CAPTURE bit is
944  * set, we will only try to capture the page if the current threads T_CAPTURING
945  * flag is not set.  If the flag is set, the unlock will not try to capture
946  * the page even though the PR_CAPTURE bit is set.
947  *
948  * Pages with PR_UE or PR_FMA flags are retired unconditionally, while pages
949  * with PR_MCE are retired if the system has not retired too many of them.
950  *
951  * A page must be exclusively locked to be retired. Pages can be retired if
952  * they are mapped, modified, or both, as long as they are not marked PR_UE,
953  * since pages with uncorrectable errors cannot be relocated in memory.
954  * Once a page has been successfully retired it is zeroed, attached to the
955  * retired_pages vnode and, finally, PR_RETIRED is set in p_toxic. The other
956  * p_toxic bits are NOT cleared. Pages are not left locked after retiring them
957  * to avoid special case code throughout the kernel; rather, page_*lock() will
958  * fail to lock the page, unless SE_RETIRED is passed as an argument.
959  *
960  * While we have your attention, go take a look at the comments at the
961  * beginning of page_retire.c too.
962  */
963 #define	PR_OK		0x00	/* no problem */
964 #define	PR_MCE		0x01	/* page has seen two or more CEs */
965 #define	PR_UE		0x02	/* page has an unhandled UE */
966 #define	PR_UE_SCRUBBED	0x04	/* page has seen a UE but was cleaned */
967 #define	PR_FMA		0x08	/* A DE wants this page retired */
968 #define	PR_CAPTURE	0x10	/* Generic page capture flag */
969 #define	PR_RESV		0x20	/* Reserved for future use */
970 #define	PR_MSG		0x40	/* message(s) already printed for this page */
971 #define	PR_RETIRED	0x80	/* This page has been retired */
972 
973 #define	PR_REASONS	(PR_UE | PR_MCE | PR_FMA)
974 #define	PR_TOXIC	(PR_UE)
975 #define	PR_ERRMASK	(PR_UE | PR_UE_SCRUBBED | PR_MCE | PR_FMA)
976 #define	PR_TOXICFLAGS	(0xCF)
977 
978 #define	PP_RETIRED(pp)	((pp)->p_toxic & PR_RETIRED)
979 #define	PP_TOXIC(pp)	((pp)->p_toxic & PR_TOXIC)
980 #define	PP_PR_REQ(pp)	(((pp)->p_toxic & PR_REASONS) && !PP_RETIRED(pp))
981 #define	PP_PR_NOSHARE(pp)						\
982 	((((pp)->p_toxic & (PR_RETIRED | PR_FMA | PR_UE)) == PR_FMA) &&	\
983 	!PP_ISKAS(pp))
984 
985 /*
986  * Flags for page_unretire_pp
987  */
988 #define	PR_UNR_FREE	0x1
989 #define	PR_UNR_CLEAN	0x2
990 #define	PR_UNR_TEMP	0x4
991 
992 /*
993  * kpm large page description.
994  * The virtual address range of segkpm is divided into chunks of
995  * kpm_pgsz. Each chunk is controlled by a kpm_page_t. The ushort
996  * is sufficient for 2^^15 * PAGESIZE, so e.g. the maximum kpm_pgsz
997  * for 8K is 256M and 2G for 64K pages. It it kept as small as
998  * possible to save physical memory space.
999  *
1000  * There are 2 segkpm mapping windows within in the virtual address
1001  * space when we have to prevent VAC alias conflicts. The so called
1002  * Alias window (mappings are always by PAGESIZE) is controlled by
1003  * kp_refcnta. The regular window is controlled by kp_refcnt for the
1004  * normal operation, which is to use the largest available pagesize.
1005  * When VAC alias conflicts are present within a chunk in the regular
1006  * window the large page mapping is broken up into smaller PAGESIZE
1007  * mappings. kp_refcntc is used to control the pages that are invoked
1008  * in the conflict and kp_refcnts holds the active mappings done
1009  * with the small page size. In non vac conflict mode kp_refcntc is
1010  * also used as "go" indication (-1) for the trap level tsbmiss
1011  * handler.
1012  */
1013 typedef struct kpm_page {
1014 	short kp_refcnt;	/* pages mapped large */
1015 	short kp_refcnta;	/* pages mapped in Alias window */
1016 	short kp_refcntc;	/* TL-tsbmiss flag; #vac alias conflict pages */
1017 	short kp_refcnts;	/* vac alias: pages mapped small */
1018 } kpm_page_t;
1019 
1020 /*
1021  * Note: khl_lock offset changes must be reflected in sfmmu_asm.s
1022  */
1023 typedef struct kpm_hlk {
1024 	kmutex_t khl_mutex;	/* kpm_page mutex */
1025 	uint_t   khl_lock;	/* trap level tsbmiss handling */
1026 } kpm_hlk_t;
1027 
1028 /*
1029  * kpm small page description.
1030  * When kpm_pgsz is equal to PAGESIZE a smaller representation is used
1031  * to save memory space. Alias range mappings and regular segkpm
1032  * mappings are done in units of PAGESIZE and can share the mapping
1033  * information and the mappings are always distinguishable by their
1034  * virtual address. Other information needed for VAC conflict prevention
1035  * is already available on a per page basis.
1036  *
1037  * The state about how a kpm page is mapped and whether it is ready to go
1038  * is indicated by the following 1 byte kpm_spage structure. This byte is
1039  * split into two 4-bit parts - kp_mapped and kp_mapped_go.
1040  * 	- kp_mapped == 1	the page is mapped cacheable
1041  *	- kp_mapped == 2	the page is mapped non-cacheable
1042  *	- kp_mapped_go == 1	the mapping is ready to be dropped in
1043  *	- kp_mapped_go == 0	the mapping is not ready to be dropped in.
1044  * When kp_mapped_go == 0, we will have C handler resolve the VAC conflict.
1045  * Otherwise, the assembly tsb miss handler can simply drop in the mapping
1046  * when a tsb miss occurs.
1047  */
1048 typedef union kpm_spage {
1049 	struct {
1050 #ifdef  _BIG_ENDIAN
1051 		uchar_t mapped_go: 4;	/* go or nogo flag */
1052 		uchar_t mapped: 4;	/* page mapped small */
1053 #else
1054 		uchar_t mapped: 4;	/* page mapped small */
1055 		uchar_t mapped_go: 4;	/* go or nogo flag */
1056 #endif
1057 	} kpm_spage_un;
1058 	uchar_t kp_mapped_flag;
1059 } kpm_spage_t;
1060 
1061 #define	kp_mapped	kpm_spage_un.mapped
1062 #define	kp_mapped_go	kpm_spage_un.mapped_go
1063 
1064 /*
1065  * Note: kshl_lock offset changes must be reflected in sfmmu_asm.s
1066  */
1067 typedef struct kpm_shlk {
1068 	uint_t   kshl_lock;	/* trap level tsbmiss handling */
1069 } kpm_shlk_t;
1070 
1071 /*
1072  * Each segment of physical memory is described by a memseg struct.
1073  * Within a segment, memory is considered contiguous. The members
1074  * can be categorized as follows:
1075  * . Platform independent:
1076  *         pages, epages, pages_base, pages_end, next, lnext.
1077  * . 64bit only but platform independent:
1078  *         kpm_pbase, kpm_nkpmpgs, kpm_pages, kpm_spages.
1079  * . Really platform or mmu specific:
1080  *         pagespa, epagespa, nextpa, kpm_pagespa.
1081  * . Mixed:
1082  *         msegflags.
1083  */
1084 struct memseg {
1085 	page_t *pages, *epages;		/* [from, to] in page array */
1086 	pfn_t pages_base, pages_end;	/* [from, to] in page numbers */
1087 	struct memseg *next;		/* next segment in list */
1088 	struct memseg *lnext;		/* next segment in deleted list */
1089 #if defined(__sparc)
1090 	uint64_t pagespa, epagespa;	/* [from, to] page array physical */
1091 	uint64_t nextpa;		/* physical next pointer */
1092 	pfn_t	kpm_pbase;		/* start of kpm range */
1093 	pgcnt_t kpm_nkpmpgs;		/* # of kpm_pgsz pages */
1094 	union _mseg_un {
1095 		kpm_page_t  *kpm_lpgs;	/* ptr to kpm_page array */
1096 		kpm_spage_t *kpm_spgs;	/* ptr to kpm_spage array */
1097 	} mseg_un;
1098 	uint64_t kpm_pagespa;		/* physical ptr to kpm (s)pages array */
1099 #endif /* __sparc */
1100 	uint_t msegflags;		/* memseg flags */
1101 };
1102 
1103 /* memseg union aliases */
1104 #define	kpm_pages	mseg_un.kpm_lpgs
1105 #define	kpm_spages	mseg_un.kpm_spgs
1106 
1107 /* msegflags */
1108 #define	MEMSEG_DYNAMIC		0x1	/* DR: memory was added dynamically */
1109 #define	MEMSEG_META_INCL	0x2	/* DR: memseg includes it's metadata */
1110 #define	MEMSEG_META_ALLOC	0x4	/* DR: memseg allocated it's metadata */
1111 
1112 /* memseg support macros */
1113 #define	MSEG_NPAGES(SEG)	((SEG)->pages_end - (SEG)->pages_base)
1114 
1115 /* memseg hash */
1116 #define	MEM_HASH_SHIFT		0x9
1117 #define	N_MEM_SLOTS		0x200		/* must be a power of 2 */
1118 #define	MEMSEG_PFN_HASH(pfn)	(((pfn)/mhash_per_slot) & (N_MEM_SLOTS - 1))
1119 
1120 /* memseg  externals */
1121 extern struct memseg *memsegs;		/* list of memory segments */
1122 extern ulong_t mhash_per_slot;
1123 extern uint64_t memsegspa;		/* memsegs as physical address */
1124 
1125 void build_pfn_hash();
1126 extern struct memseg *page_numtomemseg_nolock(pfn_t pfnum);
1127 
1128 /*
1129  * page capture related info:
1130  * The page capture routines allow us to asynchronously capture given pages
1131  * for the explicit use of the requestor.  New requestors can be added by
1132  * explicitly adding themselves to the PC_* flags below and incrementing
1133  * PC_NUM_CALLBACKS as necessary.
1134  *
1135  * Subsystems using page capture must register a callback before attempting
1136  * to capture a page.  A duration of -1 will indicate that we will never give
1137  * up while trying to capture a page and will only stop trying to capture the
1138  * given page once we have successfully captured it.  Thus the user needs to be
1139  * aware of the behavior of all callers who have a duration of -1.
1140  *
1141  * For now, only /dev/physmem and page retire use the page capture interface
1142  * and only a single request can be outstanding for a given page.  Thus, if
1143  * /dev/phsymem wants a page and page retire also wants the same page, only
1144  * the page retire request will be honored until the point in time that the
1145  * page is actually retired, at which point in time, subsequent requests by
1146  * /dev/physmem will succeed if the CAPTURE_GET_RETIRED flag was set.
1147  */
1148 
1149 #define	PC_RETIRE		(0)
1150 #define	PC_PHYSMEM		(1)
1151 #define	PC_NUM_CALLBACKS	(2)
1152 #define	PC_MASK			((1 << PC_NUM_CALLBACKS) - 1)
1153 
1154 #define	CAPTURE_RETIRE		(1 << PC_RETIRE)
1155 #define	CAPTURE_PHYSMEM		(1 << PC_PHYSMEM)
1156 
1157 #define	CAPTURE_ASYNC		(0x0200)
1158 
1159 #define	CAPTURE_GET_RETIRED	(0x1000)
1160 #define	CAPTURE_GET_CAGE	(0x2000)
1161 
1162 struct page_capture_callback {
1163 	int cb_active;		/* 1 means active, 0 means inactive */
1164 	clock_t duration;	/* the length in time that we'll attempt to */
1165 				/* capture this page asynchronously. (in HZ) */
1166 	krwlock_t cb_rwlock;
1167 	int (*cb_func)(page_t *, void *, uint_t); /* callback function */
1168 };
1169 
1170 extern kcondvar_t pc_cv;
1171 
1172 void page_capture_register_callback(uint_t index, clock_t duration,
1173     int (*cb_func)(page_t *, void *, uint_t));
1174 void page_capture_unregister_callback(uint_t index);
1175 int page_trycapture(page_t *pp, uint_t szc, uint_t flags, void *datap);
1176 void page_unlock_capture(page_t *pp);
1177 int page_capture_unretire_pp(page_t *);
1178 
1179 extern int memsegs_trylock(int);
1180 extern void memsegs_lock(int);
1181 extern void memsegs_unlock(int);
1182 extern int memsegs_lock_held(void);
1183 extern void memlist_read_lock(void);
1184 extern void memlist_read_unlock(void);
1185 extern void memlist_write_lock(void);
1186 extern void memlist_write_unlock(void);
1187 
1188 #ifdef	__cplusplus
1189 }
1190 #endif
1191 
1192 #endif	/* _VM_PAGE_H */
1193