LCOM1920-T02G10

/*        $NetBSD: uvm_object.h,v 1.33 2012/09/14 22:20:50 rmind Exp $        */

/*

 * Copyright (c) 1997 Charles D. Cranor and Washington University.

 * All rights reserved.

 *

 * 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.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.

 *

 * from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp

 */

#ifndef _UVM_UVM_OBJECT_H_

#define _UVM_UVM_OBJECT_H_

#include <sys/queue.h>

#include <sys/rbtree.h>

#include <uvm/uvm_pglist.h>

/*

 * The UVM memory object interface.  Notes:

 *

 * A UVM memory object represents a list of pages, which are managed by

 * the object's pager operations (uvm_object::pgops).  All pages belonging

 * to an object are owned by it and thus protected by the object lock.

 *

 * The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects.

 * By default, the lock is allocated dynamically using mutex_obj(9) cache.

 * Lock sharing is normally used when there is an underlying object.  For

 * example, vnode representing a file may have an underlying node, which

 * is the case for tmpfs and layered file systems.  In such case, vnode's

 * UVM object and the underlying UVM object shares the lock (note that the

 * vnode_t::v_interlock points to uvm_object::vmobjlock).

 *

 * The reference count is managed atomically for the anonymous UVM objects.

 * For other objects, it is arbitrary (may use the lock or atomics).

 */

struct uvm_object {

        kmutex_t *                vmobjlock;        /* lock on memq */

        const struct uvm_pagerops *pgops;        /* pager ops */

        struct pglist                memq;                /* pages in this object */

        int                        uo_npages;        /* # of pages in memq */

        unsigned                uo_refs;        /* reference count */

        struct rb_tree                rb_tree;        /* tree of pages */

        LIST_HEAD(,ubc_map)        uo_ubc;                /* ubc mappings */

};

/*

 * UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the

 * object is a kernel memory object rather than a normal one (kernel

 * memory objects don't have reference counts -- they never die).

 *

 * this value is used to detected kernel object mappings at uvm_unmap()

 * time.   normally when an object is unmapped its pages eventaully become

 * deactivated and then paged out and/or freed.    this is not useful

 * for kernel objects... when a kernel object is unmapped we always want

 * to free the resources associated with the mapping.   UVM_OBJ_KERN

 * allows us to decide which type of unmapping we want to do.

 */

#define UVM_OBJ_KERN                (-2)

#define        UVM_OBJ_IS_KERN_OBJECT(uobj)                                        \

        ((uobj)->uo_refs == UVM_OBJ_KERN)

#ifdef _KERNEL

extern const struct uvm_pagerops uvm_vnodeops;

extern const struct uvm_pagerops uvm_deviceops;

extern const struct uvm_pagerops ubc_pager;

extern const struct uvm_pagerops aobj_pager;

#define        UVM_OBJ_IS_VNODE(uobj)                                                \

        ((uobj)->pgops == &uvm_vnodeops)

#define        UVM_OBJ_IS_DEVICE(uobj)                                                \

        ((uobj)->pgops == &uvm_deviceops)

#define        UVM_OBJ_IS_VTEXT(uobj)                                                \

        (UVM_OBJ_IS_VNODE(uobj) && uvn_text_p(uobj))

#define        UVM_OBJ_IS_CLEAN(uobj)                                                \

        (UVM_OBJ_IS_VNODE(uobj) && uvn_clean_p(uobj))

/*

 * UVM_OBJ_NEEDS_WRITEFAULT: true if the uobj needs to detect modification.

 * (ie. wants to avoid writable user mappings.)

 *

 * XXX bad name

 */

#define        UVM_OBJ_NEEDS_WRITEFAULT(uobj)                                        \

        (UVM_OBJ_IS_VNODE(uobj) && uvn_needs_writefault_p(uobj))

#define        UVM_OBJ_IS_AOBJ(uobj)                                                \

        ((uobj)->pgops == &aobj_pager)

extern const rb_tree_ops_t uvm_page_tree_ops;

#endif /* _KERNEL */

#endif /* _UVM_UVM_OBJECT_H_ */