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28 /*
29  * @OSF_COPYRIGHT@
30  */
31 /*
32  * Mach Operating System
33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
34  * All Rights Reserved.
35  *
36  * Permission to use, copy, modify and distribute this software and its
37  * documentation is hereby granted, provided that both the copyright
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39  * software, derivative works or modified versions, and any portions
40  * thereof, and that both notices appear in supporting documentation.
41  *
42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45  *
46  * Carnegie Mellon requests users of this software to return to
47  *
48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
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51  *  Pittsburgh PA 15213-3890
52  *
53  * any improvements or extensions that they make and grant Carnegie Mellon
54  * the rights to redistribute these changes.
55  */
56 /*
57  */
58 /*
59  *	File:	mach/vm_prot.h
60  *	Author:	Avadis Tevanian, Jr., Michael Wayne Young
61  *
62  *	Virtual memory protection definitions.
63  *
64  */
65 
66 #ifndef _MACH_VM_PROT_H_
67 #define _MACH_VM_PROT_H_
68 
69 /*
70  *	Types defined:
71  *
72  *	vm_prot_t		VM protection values.
73  */
74 
75 typedef int             vm_prot_t;
76 
77 /*
78  *	Protection values, defined as bits within the vm_prot_t type
79  */
80 
81 #define VM_PROT_NONE    ((vm_prot_t) 0x00)
82 
83 #define VM_PROT_READ    ((vm_prot_t) 0x01)      /* read permission */
84 #define VM_PROT_WRITE   ((vm_prot_t) 0x02)      /* write permission */
85 #define VM_PROT_EXECUTE ((vm_prot_t) 0x04)      /* execute permission */
86 
87 /*
88  *	The default protection for newly-created virtual memory
89  */
90 
91 #define VM_PROT_DEFAULT (VM_PROT_READ|VM_PROT_WRITE)
92 
93 /*
94  *	The maximum privileges possible, for parameter checking.
95  */
96 
97 #define VM_PROT_ALL     (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
98 
99 /*
100  *	An invalid protection value.
101  *	Used only by memory_object_lock_request to indicate no change
102  *	to page locks.  Using -1 here is a bad idea because it
103  *	looks like VM_PROT_ALL and then some.
104  */
105 
106 #define VM_PROT_NO_CHANGE       ((vm_prot_t) 0x08)
107 
108 /*
109  *      When a caller finds that he cannot obtain write permission on a
110  *      mapped entry, the following flag can be used.  The entry will
111  *      be made "needs copy" effectively copying the object (using COW),
112  *      and write permission will be added to the maximum protections
113  *      for the associated entry.
114  */
115 
116 #define VM_PROT_COPY            ((vm_prot_t) 0x10)
117 
118 
119 /*
120  *	Another invalid protection value.
121  *	Used only by memory_object_data_request upon an object
122  *	which has specified a copy_call copy strategy. It is used
123  *	when the kernel wants a page belonging to a copy of the
124  *	object, and is only asking the object as a result of
125  *	following a shadow chain. This solves the race between pages
126  *	being pushed up by the memory manager and the kernel
127  *	walking down the shadow chain.
128  */
129 
130 #define VM_PROT_WANTS_COPY      ((vm_prot_t) 0x10)
131 
132 
133 /*
134  *      Another invalid protection value.
135  *	Indicates that the other protection bits are to be applied as a mask
136  *	against the actual protection bits of the map entry.
137  */
138 #define VM_PROT_IS_MASK         ((vm_prot_t) 0x40)
139 
140 /*
141  * Another invalid protection value to support execute-only protection.
142  * VM_PROT_STRIP_READ is a special marker that tells mprotect to not
143  * set VM_PROT_READ. We have to do it this way because existing code
144  * expects the system to set VM_PROT_READ if VM_PROT_EXECUTE is set.
145  * VM_PROT_EXECUTE_ONLY is just a convenience value to indicate that
146  * the memory should be executable and explicitly not readable. It will
147  * be ignored on platforms that do not support this type of protection.
148  */
149 #define VM_PROT_STRIP_READ              ((vm_prot_t) 0x80)
150 #define VM_PROT_EXECUTE_ONLY    (VM_PROT_EXECUTE|VM_PROT_STRIP_READ)
151 
152 #endif  /* _MACH_VM_PROT_H_ */