uvm_map.c

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/*	$NetBSD: uvm_map.c,v 1.86 2000/11/27 08:40:03 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.c    8.3 (Berkeley) 1/12/94
 * from: Id: uvm_map.c,v 1.1.2.27 1998/02/07 01:16:54 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  [e-mail]
 *  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.
 */

#include "opt_ddb.h"
#include "opt_uvmhist.h"
#include "opt_sysv.h"

/*
 * uvm_map.c: uvm map operations
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mman.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/pool.h>

#ifdef SYSVSHM
#include <sys/shm.h>
#endif

#define UVM_MAP
#include <uvm/uvm.h>

#ifdef DDB
#include <uvm/uvm_ddb.h>
#endif

struct uvm_cnt uvm_map_call, map_backmerge, map_forwmerge;
struct uvm_cnt uvm_mlk_call, uvm_mlk_hint;

/*
 * pool for vmspace structures.
 */

struct pool uvm_vmspace_pool;

/*
 * pool for dynamically-allocated map entries.
 */

struct pool uvm_map_entry_pool;

#ifdef PMAP_GROWKERNEL
/*
 * This global represents the end of the kernel virtual address
 * space.  If we want to exceed this, we must grow the kernel
 * virtual address space dynamically.
 *
 * Note, this variable is locked by kernel_map's lock.
 */
vaddr_t uvm_maxkaddr;
#endif

/*
 * macros
 */

/*
 * uvm_map_entry_link: insert entry into a map
 *
 * => map must be locked
 */
#define uvm_map_entry_link(map, after_where, entry) do { \
	(map)->nentries++; \
	(entry)->prev = (after_where); \
	(entry)->next = (after_where)->next; \
	(entry)->prev->next = (entry); \
	(entry)->next->prev = (entry); \
} while (0)

/*
 * uvm_map_entry_unlink: remove entry from a map
 *
 * => map must be locked
 */
#define uvm_map_entry_unlink(map, entry) do { \
	(map)->nentries--; \
	(entry)->next->prev = (entry)->prev; \
	(entry)->prev->next = (entry)->next; \
} while (0)

/*
 * SAVE_HINT: saves the specified entry as the hint for future lookups.
 *
 * => map need not be locked (protected by hint_lock).
 */
#define SAVE_HINT(map,check,value) do { \
	simple_lock(&(map)->hint_lock); \
	if ((map)->hint == (check)) \
		(map)->hint = (value); \
	simple_unlock(&(map)->hint_lock); \
} while (0)

/*
 * VM_MAP_RANGE_CHECK: check and correct range
 *
 * => map must at least be read locked
 */

#define VM_MAP_RANGE_CHECK(map, start, end) do { \
	if (start < vm_map_min(map)) 		\
		start = vm_map_min(map);        \
	if (end > vm_map_max(map))              \
		end = vm_map_max(map);          \
	if (start > end)                        \
		start = end;                    \
} while (0)

/*
 * local prototypes
 */

static vm_map_entry_t	uvm_mapent_alloc __P((vm_map_t));
static void		uvm_mapent_copy __P((vm_map_entry_t,vm_map_entry_t));
static void		uvm_mapent_free __P((vm_map_entry_t));
static void		uvm_map_entry_unwire __P((vm_map_t, vm_map_entry_t));
static void		uvm_map_reference_amap __P((vm_map_entry_t, int));
static void		uvm_map_unreference_amap __P((vm_map_entry_t, int));

/*
 * local inlines
 */

/*
 * uvm_mapent_alloc: allocate a map entry
 *
 * => XXX: static pool for kernel map?
 */

static __inline vm_map_entry_t
uvm_mapent_alloc(map)
	vm_map_t map;
{
	vm_map_entry_t me;
	int s;
	UVMHIST_FUNC("uvm_mapent_alloc");
	UVMHIST_CALLED(maphist);

	if ((map->flags & VM_MAP_INTRSAFE) == 0 &&
	    map != kernel_map && kernel_map != NULL /* XXX */) {
		me = pool_get(&uvm_map_entry_pool, PR_WAITOK);
		me->flags = 0;
		/* me can't be null, wait ok */
	} else {
		s = splimp();	/* protect kentry_free list with splimp */
		simple_lock(&uvm.kentry_lock);
		me = uvm.kentry_free;
		if (me) uvm.kentry_free = me->next;
		simple_unlock(&uvm.kentry_lock);
		splx(s);
		if (!me)
	panic("mapent_alloc: out of static map entries, check MAX_KMAPENT");
		me->flags = UVM_MAP_STATIC;
	}

	UVMHIST_LOG(maphist, "<- new entry=0x%x [kentry=%d]", 
		me, ((map->flags & VM_MAP_INTRSAFE) != 0 || map == kernel_map)
		? TRUE : FALSE, 0, 0);
	return(me);
}

/*
 * uvm_mapent_free: free map entry
 *
 * => XXX: static pool for kernel map?
 */

static __inline void
uvm_mapent_free(me)
	vm_map_entry_t me;
{
	int s;
	UVMHIST_FUNC("uvm_mapent_free");
	UVMHIST_CALLED(maphist);
	UVMHIST_LOG(maphist,"<- freeing map entry=0x%x [flags=%d]", 
		me, me->flags, 0, 0);
	if ((me->flags & UVM_MAP_STATIC) == 0) {
		pool_put(&uvm_map_entry_pool, me);
	} else {
		s = splimp();	/* protect kentry_free list with splimp */
		simple_lock(&uvm.kentry_lock);
		me->next = uvm.kentry_free;
		uvm.kentry_free = me;
		simple_unlock(&uvm.kentry_lock);
		splx(s);
	}
}

/*
 * uvm_mapent_copy: copy a map entry, preserving flags
 */

static __inline void
uvm_mapent_copy(src, dst)
	vm_map_entry_t src;
	vm_map_entry_t dst;
{

	memcpy(dst, src, ((char *)&src->uvm_map_entry_stop_copy) - ((char*)src));
}

/*
 * uvm_map_entry_unwire: unwire a map entry
 *
 * => map should be locked by caller
 */

static __inline void
uvm_map_entry_unwire(map, entry)
	vm_map_t map;
	vm_map_entry_t entry;
{

	entry->wired_count = 0;
	uvm_fault_unwire_locked(map, entry->start, entry->end);
}


/*
 * wrapper for calling amap_ref()
 */
static __inline void
uvm_map_reference_amap(entry, flags)
	vm_map_entry_t entry;
	int flags;
{
    amap_ref(entry->aref.ar_amap, entry->aref.ar_pageoff,
	     (entry->end - entry->start) >> PAGE_SHIFT, flags);
}


/*
 * wrapper for calling amap_unref() 
 */
static __inline void
uvm_map_unreference_amap(entry, flags)
	vm_map_entry_t entry;
	int flags;
{
    amap_unref(entry->aref.ar_amap, entry->aref.ar_pageoff,
	     (entry->end - entry->start) >> PAGE_SHIFT, flags);
}


/*
 * uvm_map_init: init mapping system at boot time.   note that we allocate
 * and init the static pool of vm_map_entry_t's for the kernel here.
 */

void
uvm_map_init() 
{
	static struct vm_map_entry kernel_map_entry[MAX_KMAPENT];
#if defined(UVMHIST)
	static struct uvm_history_ent maphistbuf[100];
	static struct uvm_history_ent pdhistbuf[100];
#endif
	int lcv;

	/*
	 * first, init logging system.
	 */

	UVMHIST_FUNC("uvm_map_init");
	UVMHIST_INIT_STATIC(maphist, maphistbuf);
	UVMHIST_INIT_STATIC(pdhist, pdhistbuf);
	UVMHIST_CALLED(maphist);
	UVMHIST_LOG(maphist,"<starting uvm map system>", 0, 0, 0, 0);
	UVMCNT_INIT(uvm_map_call,  UVMCNT_CNT, 0,
	    "# uvm_map() successful calls", 0);
	UVMCNT_INIT(map_backmerge, UVMCNT_CNT, 0, "# uvm_map() back merges", 0);
	UVMCNT_INIT(map_forwmerge, UVMCNT_CNT, 0, "# uvm_map() missed forward",
	    0);
	UVMCNT_INIT(uvm_mlk_call,  UVMCNT_CNT, 0, "# map lookup calls", 0);
	UVMCNT_INIT(uvm_mlk_hint,  UVMCNT_CNT, 0, "# map lookup hint hits", 0);

	/*
	 * now set up static pool of kernel map entrys ...
	 */

	simple_lock_init(&uvm.kentry_lock);
	uvm.kentry_free = NULL;
	for (lcv = 0 ; lcv < MAX_KMAPENT ; lcv++) {
		kernel_map_entry[lcv].next = uvm.kentry_free;
		uvm.kentry_free = &kernel_map_entry[lcv];
	}

	/*
	 * initialize the map-related pools.
	 */
	pool_init(&uvm_vmspace_pool, sizeof(struct vmspace),
	    0, 0, 0, "vmsppl", 0,
	    pool_page_alloc_nointr, pool_page_free_nointr, M_VMMAP);
	pool_init(&uvm_map_entry_pool, sizeof(struct vm_map_entry),
	    0, 0, 0, "vmmpepl", 0,
	    pool_page_alloc_nointr, pool_page_free_nointr, M_VMMAP);
}

/*
 * clippers
 */

/*
 * uvm_map_clip_start: ensure that the entry begins at or after
 *	the starting address, if it doesn't we split the entry.
 * 
 * => caller should use UVM_MAP_CLIP_START macro rather than calling
 *    this directly
 * => map must be locked by caller
 */

void uvm_map_clip_start(map, entry, start)
	vm_map_t       map;
	vm_map_entry_t entry;
	vaddr_t    start;
{
	vm_map_entry_t new_entry;
	vaddr_t new_adj;

	/* uvm_map_simplify_entry(map, entry); */ /* XXX */

	/*
	 * Split off the front portion.  note that we must insert the new
	 * entry BEFORE this one, so that this entry has the specified
	 * starting address.
	 */

	new_entry = uvm_mapent_alloc(map);
	uvm_mapent_copy(entry, new_entry); /* entry -> new_entry */

	new_entry->end = start; 
	new_adj = start - new_entry->start;
	if (entry->object.uvm_obj)
		entry->offset += new_adj;	/* shift start over */
	entry->start = start;

	if (new_entry->aref.ar_amap) {
		amap_splitref(&new_entry->aref, &entry->aref, new_adj);
	}

	uvm_map_entry_link(map, entry->prev, new_entry);

	if (UVM_ET_ISSUBMAP(entry)) {
		/* ... unlikely to happen, but play it safe */
		 uvm_map_reference(new_entry->object.sub_map);
	} else {
		if (UVM_ET_ISOBJ(entry) && 
		    entry->object.uvm_obj->pgops &&
		    entry->object.uvm_obj->pgops->pgo_reference)
			entry->object.uvm_obj->pgops->pgo_reference(
			    entry->object.uvm_obj);
	}
}

/*
 * uvm_map_clip_end: ensure that the entry ends at or before
 *	the ending address, if it does't we split the reference
 * 
 * => caller should use UVM_MAP_CLIP_END macro rather than calling
 *    this directly
 * => map must be locked by caller
 */

void
uvm_map_clip_end(map, entry, end)
	vm_map_t	map;
	vm_map_entry_t	entry;
	vaddr_t	end;
{
	vm_map_entry_t	new_entry;
	vaddr_t new_adj; /* #bytes we move start forward */

	/*
	 *	Create a new entry and insert it
	 *	AFTER the specified entry
	 */

	new_entry = uvm_mapent_alloc(map);
	uvm_mapent_copy(entry, new_entry); /* entry -> new_entry */

	new_entry->start = entry->end = end;
	new_adj = end - entry->start;
	if (new_entry->object.uvm_obj)
		new_entry->offset += new_adj;

	if (entry->aref.ar_amap)
		amap_splitref(&entry->aref, &new_entry->aref, new_adj);

	uvm_map_entry_link(map, entry, new_entry);

	if (UVM_ET_ISSUBMAP(entry)) {
		/* ... unlikely to happen, but play it safe */
	 	uvm_map_reference(new_entry->object.sub_map);
	} else {
		if (UVM_ET_ISOBJ(entry) &&
		    entry->object.uvm_obj->pgops &&
		    entry->object.uvm_obj->pgops->pgo_reference)
			entry->object.uvm_obj->pgops->pgo_reference(
			    entry->object.uvm_obj);
	}
}


/*
 *   M A P   -   m a i n   e n t r y   p o i n t
 */
/*
 * uvm_map: establish a valid mapping in a map
 *
 * => assume startp is page aligned.
 * => assume size is a multiple of PAGE_SIZE.
 * => assume sys_mmap provides enough of a "hint" to have us skip
 *	over text/data/bss area.
 * => map must be unlocked (we will lock it)
 * => <uobj,uoffset> value meanings (4 cases):
 *	 [1] <NULL,uoffset> 		== uoffset is a hint for PMAP_PREFER
 *	 [2] <NULL,UVM_UNKNOWN_OFFSET>	== don't PMAP_PREFER
 *	 [3] <uobj,uoffset>		== normal mapping
 *	 [4] <uobj,UVM_UNKNOWN_OFFSET>	== uvm_map finds offset based on VA
 *	
 *    case [4] is for kernel mappings where we don't know the offset until
 *    we've found a virtual address.   note that kernel object offsets are
 *    always relative to vm_map_min(kernel_map).