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There are two related changes.

The first one is an mquery(2) syscall. It's for asking the VM system
about where to map things. It will be used by ld.so, read the man page
for details.

The second change is related and is a centralization of uvm_map hint
that all callers of uvm_map calculated. This will allow us to adjust
this hint on architectures that have segments for non-exec mappings.

deraadt@ drahn@ ok.

/*	$OpenBSD: uvm_map.h,v 1.29 2003/04/14 04:53:51 art Exp $	*/
/*	$NetBSD: uvm_map.h,v 1.24 2001/02/18 21:19:08 chs Exp $	*/

/* 
 * Copyright (c) 1997 Charles D. Cranor and Washington University.
 * Copyright (c) 1991, 1993, The Regents of the University of California.  
 *
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * The Mach Operating System project at Carnegie-Mellon University.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Charles D. Cranor,
 *      Washington University, the University of California, Berkeley and 
 *      its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)vm_map.h    8.3 (Berkeley) 3/15/94
 * from: Id: uvm_map.h,v 1.1.2.3 1998/02/07 01:16:55 chs Exp
 *
 *
 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
 * All rights reserved.
 * 
 * Permission to use, copy, modify and distribute this software and
 * its documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

#ifndef _UVM_UVM_MAP_H_
#define _UVM_UVM_MAP_H_

/*
 * uvm_map.h
 */

#ifdef _KERNEL

/*
 * macros
 */

/*
 * UVM_MAP_CLIP_START: ensure that the entry begins at or after
 * the starting address, if it doesn't we split the entry.
 * 
 * => map must be locked by caller
 */

#define UVM_MAP_CLIP_START(MAP,ENTRY,VA) { \
	if ((VA) > (ENTRY)->start) uvm_map_clip_start(MAP,ENTRY,VA); }

/*
 * UVM_MAP_CLIP_END: ensure that the entry ends at or before
 *      the ending address, if it does't we split the entry.
 *
 * => map must be locked by caller
 */

#define UVM_MAP_CLIP_END(MAP,ENTRY,VA) { \
	if ((VA) < (ENTRY)->end) uvm_map_clip_end(MAP,ENTRY,VA); }

/*
 * extract flags
 */
#define UVM_EXTRACT_REMOVE	0x1	/* remove mapping from old map */
#define UVM_EXTRACT_CONTIG	0x2	/* try to keep it contig */
#define UVM_EXTRACT_QREF	0x4	/* use quick refs */
#define UVM_EXTRACT_FIXPROT	0x8	/* set prot to maxprot as we go */

#endif /* _KERNEL */

#include <uvm/uvm_anon.h>

/*
 * types defined:
 *
 *	vm_map_t		the high-level address map data structure.
 *	vm_map_entry_t		an entry in an address map.
 *	vm_map_version_t	a timestamp of a map, for use with vm_map_lookup
 */

/*
 * Objects which live in maps may be either VM objects, or another map
 * (called a "sharing map") which denotes read-write sharing with other maps.
 *
 * XXXCDC: private pager data goes here now
 */

union vm_map_object {
	struct uvm_object	*uvm_obj;	/* UVM OBJECT */
	struct vm_map		*sub_map;	/* belongs to another map */
};

/*
 * Address map entries consist of start and end addresses,
 * a VM object (or sharing map) and offset into that object,
 * and user-exported inheritance and protection information.
 * Also included is control information for virtual copy operations.
 */
struct vm_map_entry {
	RB_ENTRY(vm_map_entry)	rb_entry;	/* tree information */
	vaddr_t			ownspace;	/* free space after */
	vaddr_t			space;		/* space in subtree */
	struct vm_map_entry	*prev;		/* previous entry */
	struct vm_map_entry	*next;		/* next entry */
	vaddr_t			start;		/* start address */
	vaddr_t			end;		/* end address */
	union vm_map_object	object;		/* object I point to */
	voff_t			offset;		/* offset into object */
	int			etype;		/* entry type */
	vm_prot_t		protection;	/* protection code */
	vm_prot_t		max_protection;	/* maximum protection */
	vm_inherit_t		inheritance;	/* inheritance */
	int			wired_count;	/* can be paged if == 0 */
	struct vm_aref		aref;		/* anonymous overlay */
	int			advice;		/* madvise advice */
#define uvm_map_entry_stop_copy flags
	u_int8_t		flags;		/* flags */

#define UVM_MAP_STATIC		0x01		/* static map entry */
#define UVM_MAP_KMEM		0x02		/* from kmem entry pool */

};

#define	VM_MAPENT_ISWIRED(entry)	((entry)->wired_count != 0)

/*
 *	Maps are doubly-linked lists of map entries, kept sorted
 *	by address.  A single hint is provided to start
 *	searches again from the last successful search,
 *	insertion, or removal.
 *
 *	LOCKING PROTOCOL NOTES:
 *	-----------------------
 *
 *	VM map locking is a little complicated.  There are both shared
 *	and exclusive locks on maps.  However, it is sometimes required
 *	to downgrade an exclusive lock to a shared lock, and upgrade to
 *	an exclusive lock again (to perform error recovery).  However,
 *	another thread *must not* queue itself to receive an exclusive
 *	lock while before we upgrade back to exclusive, otherwise the
 *	error recovery becomes extremely difficult, if not impossible.
 *
 *	In order to prevent this scenario, we introduce the notion of
 *	a `busy' map.  A `busy' map is read-locked, but other threads
 *	attempting to write-lock wait for this flag to clear before
 *	entering the lock manager.  A map may only be marked busy
 *	when the map is write-locked (and then the map must be downgraded
 *	to read-locked), and may only be marked unbusy by the thread
 *	which marked it busy (holding *either* a read-lock or a
 *	write-lock, the latter being gained by an upgrade).
 *
 *	Access to the map `flags' member is controlled by the `flags_lock'
 *	simple lock.  Note that some flags are static (set once at map
 *	creation time, and never changed), and thus require no locking
 *	to check those flags.  All flags which are r/w must be set or
 *	cleared while the `flags_lock' is asserted.  Additional locking
 *	requirements are:
 *
 *		VM_MAP_PAGEABLE		r/o static flag; no locking required
 *
 *		VM_MAP_INTRSAFE		r/o static flag; no locking required
 *
 *		VM_MAP_WIREFUTURE	r/w; may only be set or cleared when
 *					map is write-locked.  may be tested
 *					without asserting `flags_lock'.
 *
 *		VM_MAP_BUSY		r/w; may only be set when map is
 *					write-locked, may only be cleared by
 *					thread which set it, map read-locked
 *					or write-locked.  must be tested
 *					while `flags_lock' is asserted.
 *
 *		VM_MAP_WANTLOCK		r/w; may only be set when the map
 *					is busy, and thread is attempting
 *					to write-lock.  must be tested
 *					while `flags_lock' is asserted.
 */
struct vm_map {
	struct pmap *		pmap;		/* Physical map */
	lock_data_t		lock;		/* Lock for map data */
	RB_HEAD(uvm_tree, vm_map_entry) rbhead;	/* Tree for entries */
	struct vm_map_entry	header;		/* List of entries */
	int			nentries;	/* Number of entries */
	vsize_t			size;		/* virtual size */
	int			ref_count;	/* Reference count */
	simple_lock_data_t	ref_lock;	/* Lock for ref_count field */
	vm_map_entry_t		hint;		/* hint for quick lookups */
	simple_lock_data_t	hint_lock;	/* lock for hint storage */
	vm_map_entry_t		first_free;	/* First free space hint */
	int			flags;		/* flags */
	simple_lock_data_t	flags_lock;	/* Lock for flags field */
	unsigned int		timestamp;	/* Version number */
#define	min_offset		header.start
#define max_offset		header.end
};

/* vm_map flags */
#define	VM_MAP_PAGEABLE		0x01		/* ro: entries are pageable */
#define	VM_MAP_INTRSAFE		0x02		/* ro: interrupt safe map */
#define	VM_MAP_WIREFUTURE	0x04		/* rw: wire future mappings */
#define	VM_MAP_BUSY		0x08		/* rw: map is busy */
#define	VM_MAP_WANTLOCK		0x10		/* rw: want to write-lock */

/* XXX: number of kernel maps and entries to statically allocate */

#if !defined(MAX_KMAPENT)
#if (50 + (2 * NPROC) > 1000)
#define MAX_KMAPENT (50 + (2 * NPROC))
#else
#define	MAX_KMAPENT	1000  /* XXXCDC: no crash */
#endif
#endif	/* !defined MAX_KMAPENT */

#ifdef _KERNEL
#define	vm_map_modflags(map, set, clear)				\
do {									\
	simple_lock(&(map)->flags_lock);				\
	(map)->flags = ((map)->flags | (set)) & ~(clear);		\
	simple_unlock(&(map)->flags_lock);				\
} while (0)
#endif /* _KERNEL */

/*
 *	Interrupt-safe maps must also be kept on a special list,
 *	to assist uvm_fault() in avoiding locking problems.
 */
struct vm_map_intrsafe {
	struct vm_map	vmi_map;
	LIST_ENTRY(vm_map_intrsafe) vmi_list;
};

LIST_HEAD(vmi_list, vm_map_intrsafe);
#ifdef _KERNEL
extern simple_lock_data_t vmi_list_slock;
extern struct vmi_list vmi_list;

static __inline int vmi_list_lock(void);
static __inline void vmi_list_unlock(int);

static __inline int
vmi_list_lock()
{
	int s;

	s = splhigh();
	simple_lock(&vmi_list_slock);
	return (s);
}

static __inline void
vmi_list_unlock(s)
	int s;
{

	simple_unlock(&vmi_list_slock);
	splx(s);
}
#endif /* _KERNEL */

/*
 * handle inline options
 */

#ifdef UVM_MAP_INLINE
#define MAP_INLINE static __inline
#else 
#define MAP_INLINE /* nothing */
#endif /* UVM_MAP_INLINE */

/*
 * globals:
 */

#ifdef _KERNEL

#ifdef PMAP_GROWKERNEL
extern vaddr_t	uvm_maxkaddr;
#endif

/*
 * protos: the following prototypes define the interface to vm_map
 */

MAP_INLINE
void		uvm_map_deallocate(vm_map_t);

int		uvm_map_clean(vm_map_t, vaddr_t, vaddr_t, int);
void		uvm_map_clip_start(vm_map_t, vm_map_entry_t, vaddr_t);
void		uvm_map_clip_end(vm_map_t, vm_map_entry_t, vaddr_t);
MAP_INLINE
vm_map_t	uvm_map_create(pmap_t, vaddr_t, vaddr_t, int);
int		uvm_map_extract(vm_map_t, vaddr_t, vsize_t, 
			vm_map_t, vaddr_t *, int);
vm_map_entry_t	uvm_map_findspace(vm_map_t, vaddr_t, vsize_t, vaddr_t *,
			struct uvm_object *, voff_t, vsize_t, int);
vaddr_t		uvm_map_hint(struct proc *, vm_prot_t);
int		uvm_map_inherit(vm_map_t, vaddr_t, vaddr_t, vm_inherit_t);
int		uvm_map_advice(vm_map_t, vaddr_t, vaddr_t, int);
void		uvm_map_init(void);
boolean_t	uvm_map_lookup_entry(vm_map_t, vaddr_t, vm_map_entry_t *);
MAP_INLINE
void		uvm_map_reference(vm_map_t);
int		uvm_map_replace(vm_map_t, vaddr_t, vaddr_t,
			vm_map_entry_t, int);
int		uvm_map_reserve(vm_map_t, vsize_t, vaddr_t, vsize_t,
			vaddr_t *);
void		uvm_map_setup(vm_map_t, vaddr_t, vaddr_t, int);
int		uvm_map_submap(vm_map_t, vaddr_t, vaddr_t, vm_map_t);
MAP_INLINE
void		uvm_unmap(vm_map_t, vaddr_t, vaddr_t);
void		uvm_unmap_detach(vm_map_entry_t,int);
void		uvm_unmap_remove(vm_map_t, vaddr_t, vaddr_t,
				      vm_map_entry_t *);

#endif /* _KERNEL */

/*
 * VM map locking operations:
 *
 *	These operations perform locking on the data portion of the
 *	map.
 *
 *	vm_map_lock_try: try to lock a map, failing if it is already locked.
 *
 *	vm_map_lock: acquire an exclusive (write) lock on a map.
 *
 *	vm_map_lock_read: acquire a shared (read) lock on a map.
 *
 *	vm_map_unlock: release an exclusive lock on a map.
 *
 *	vm_map_unlock_read: release a shared lock on a map.
 *
 *	vm_map_downgrade: downgrade an exclusive lock to a shared lock.
 *
 *	vm_map_upgrade: upgrade a shared lock to an exclusive lock.
 *
 *	vm_map_busy: mark a map as busy.
 *
 *	vm_map_unbusy: clear busy status on a map.
 *
 * Note that "intrsafe" maps use only exclusive, spin locks.  We simply
 * use the sleep lock's interlock for this.
 */

#ifdef _KERNEL
/* XXX: clean up later */
#include <sys/time.h>
#include <sys/proc.h>	/* for tsleep(), wakeup() */
#include <sys/systm.h>	/* for panic() */

static __inline boolean_t vm_map_lock_try(vm_map_t);
static __inline void vm_map_lock(vm_map_t);
extern const char vmmapbsy[];

static __inline boolean_t
vm_map_lock_try(map)
	vm_map_t map;
{
	boolean_t rv;

	if (map->flags & VM_MAP_INTRSAFE)
		rv = simple_lock_try(&map->lock.lk_interlock);
	else {
		simple_lock(&map->flags_lock);
		if (map->flags & VM_MAP_BUSY) {
			simple_unlock(&map->flags_lock);
			return (FALSE);
		}
		rv = (lockmgr(&map->lock, LK_EXCLUSIVE|LK_NOWAIT|LK_INTERLOCK,
		    &map->flags_lock, curproc) == 0);
	}

	if (rv)
		map->timestamp++;

	return (rv);
}

static __inline void
vm_map_lock(map)
	vm_map_t map;
{
	int error;

	if (map->flags & VM_MAP_INTRSAFE) {
		simple_lock(&map->lock.lk_interlock);
		return;
	}

 try_again:
	simple_lock(&map->flags_lock);
	while (map->flags & VM_MAP_BUSY) {
		map->flags |= VM_MAP_WANTLOCK;
		ltsleep(&map->flags, PVM, (char *)vmmapbsy, 0, &map->flags_lock);
	}

	error = lockmgr(&map->lock, LK_EXCLUSIVE|LK_SLEEPFAIL|LK_INTERLOCK,
	    &map->flags_lock, curproc);

	if (error) {
		goto try_again;
	}

	(map)->timestamp++;
}

#ifdef DIAGNOSTIC
#define	vm_map_lock_read(map)						\
do {									\
	if (map->flags & VM_MAP_INTRSAFE)				\
		panic("vm_map_lock_read: intrsafe map");		\
	(void) lockmgr(&(map)->lock, LK_SHARED, NULL, curproc);		\
} while (0)
#else
#define	vm_map_lock_read(map)						\
	(void) lockmgr(&(map)->lock, LK_SHARED, NULL, curproc)
#endif

#define	vm_map_unlock(map)						\
do {									\
	if ((map)->flags & VM_MAP_INTRSAFE)				\
		simple_unlock(&(map)->lock.lk_interlock);		\
	else								\
		(void) lockmgr(&(map)->lock, LK_RELEASE, NULL, curproc);\
} while (0)

#define	vm_map_unlock_read(map)						\
	(void) lockmgr(&(map)->lock, LK_RELEASE, NULL, curproc)

#define	vm_map_downgrade(map)						\
	(void) lockmgr(&(map)->lock, LK_DOWNGRADE, NULL, curproc)

#ifdef DIAGNOSTIC
#define	vm_map_upgrade(map)						\
do {									\
	if (lockmgr(&(map)->lock, LK_UPGRADE, NULL, curproc) != 0)	\
		panic("vm_map_upgrade: failed to upgrade lock");	\
} while (0)
#else
#define	vm_map_upgrade(map)						\
	(void) lockmgr(&(map)->lock, LK_UPGRADE, NULL, curproc)
#endif

#define	vm_map_busy(map)						\
do {									\
	simple_lock(&(map)->flags_lock);				\
	(map)->flags |= VM_MAP_BUSY;					\
	simple_unlock(&(map)->flags_lock);				\
} while (0)

#define	vm_map_unbusy(map)						\
do {									\
	int oflags;							\
									\
	simple_lock(&(map)->flags_lock);				\
	oflags = (map)->flags;						\
	(map)->flags &= ~(VM_MAP_BUSY|VM_MAP_WANTLOCK);			\
	simple_unlock(&(map)->flags_lock);				\
	if (oflags & VM_MAP_WANTLOCK)					\
		wakeup(&(map)->flags);					\
} while (0)
#endif /* _KERNEL */

/*
 *	Functions implemented as macros
 */
#define		vm_map_min(map)		((map)->min_offset)
#define		vm_map_max(map)		((map)->max_offset)
#define		vm_map_pmap(map)	((map)->pmap)

#endif /* _UVM_UVM_MAP_H_ */