xref: /illumos-gate/usr/src/uts/common/vm/vpage.h (revision 0250c53ad267726f2438e3c6556199a0bbf588a2)
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 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  * Copyright (c) 2015, Joyent, Inc.  All rights reserved.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved	*/
29 
30 /*
31  * University Copyright- Copyright (c) 1982, 1986, 1988
32  * The Regents of the University of California
33  * All Rights Reserved
34  *
35  * University Acknowledgment- Portions of this document are derived from
36  * software developed by the University of California, Berkeley, and its
37  * contributors.
38  */
39 
40 #ifndef	_VM_VPAGE_H
41 #define	_VM_VPAGE_H
42 
43 #ifdef	__cplusplus
44 extern "C" {
45 #endif
46 
47 /*
48  * VM - Information per virtual page.
49  */
50 struct vpage {
51 	uchar_t nvp_prot;	/* see <sys/mman.h> prot flags */
52 	uchar_t nvp_advice;	/* pplock & <sys/mman.h> madvise flags */
53 };
54 
55 /*
56  * This was changed from a bitfield to flags/macros in order
57  * to conserve space (uchar_t bitfields are not ANSI).  This could
58  * have been condensed to a uchar_t, but at the expense of complexity.
59  * We've stolen three bits from the top of nvp_advice: the first to store
60  * pplock, the second to identify pages for which we have reserved
61  * swap space, but have not necessarily allocated anon slots, and the third to
62  * indicate that the page should be zeroed on fork.
63  *
64  * WARNING: VPP_SETADVICE(vpp, x) evaluates vpp twice, and VPP_PLOCK(vpp)
65  * returns a positive integer when the lock is held, not necessarily (1).
66  */
67 #define	VP_ADVICE_MASK	(0x07)
68 #define	VP_PPLOCK_MASK	(0x80)	/* physical page locked by me */
69 #define	VP_PPLOCK_SHIFT	(0x07)	/* offset of lock hiding inside nvp_advice */
70 #define	VP_SWAPRES_MASK	(0x40)	/* Swap space has been reserved, but we */
71 				/* might not have allocated an anon slot */
72 #define	VP_INHZERO_MASK	(0x20)	/* zero page on fork() */
73 
74 #define	VPP_PROT(vpp)	((vpp)->nvp_prot)
75 #define	VPP_ADVICE(vpp)	((vpp)->nvp_advice & VP_ADVICE_MASK)
76 #define	VPP_ISPPLOCK(vpp) \
77 	((uchar_t)((vpp)->nvp_advice & VP_PPLOCK_MASK))
78 #define	VPP_ISSWAPRES(vpp) \
79 	((uchar_t)((vpp)->nvp_advice & VP_SWAPRES_MASK))
80 #define	VPP_ISINHZERO(vpp) \
81 	((uchar_t)((vpp)->nvp_advice & VP_INHZERO_MASK))
82 
83 #define	VPP_SETPROT(vpp, x)	((vpp)->nvp_prot = (x))
84 #define	VPP_SETADVICE(vpp, x) \
85 	((vpp)->nvp_advice = ((vpp)->nvp_advice & ~VP_ADVICE_MASK) | \
86 		((x) & VP_ADVICE_MASK))
87 #define	VPP_SETPPLOCK(vpp)	((vpp)->nvp_advice |= VP_PPLOCK_MASK)
88 #define	VPP_CLRPPLOCK(vpp)	((vpp)->nvp_advice &= ~VP_PPLOCK_MASK)
89 #define	VPP_SETSWAPRES(vpp)	((vpp)->nvp_advice |= VP_SWAPRES_MASK)
90 #define	VPP_CLRSWAPRES(vpp)	((vpp)->nvp_advice &= ~VP_SWAPRES_MASK)
91 #define	VPP_SETINHZERO(vpp)	((vpp)->nvp_advice |= VP_INHZERO_MASK)
92 #define	VPP_CLRINHZERO(vpp)	((vpp)->nvp_advice &= ~VP_INHZERO_MASK)
93 
94 #ifdef	__cplusplus
95 }
96 #endif
97 
98 #endif	/* _VM_VPAGE_H */
99