osfmk/mach/vm_prot.h

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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  25  * Please see the License for the specific language governing rights and
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  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*
  31  * @OSF_COPYRIGHT@
  32  */
  33 /*
  34  * Mach Operating System
  35  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  36  * All Rights Reserved.
  37  *
  38  * Permission to use, copy, modify and distribute this software and its
  39  * documentation is hereby granted, provided that both the copyright
  40  * notice and this permission notice appear in all copies of the
  41  * software, derivative works or modified versions, and any portions
  42  * thereof, and that both notices appear in supporting documentation.
  43  *
  44  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  45  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  46  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  47  *
  48  * Carnegie Mellon requests users of this software to return to
  49  *
  50  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  51  *  School of Computer Science
  52  *  Carnegie Mellon University
  53  *  Pittsburgh PA 15213-3890
  54  *
  55  * any improvements or extensions that they make and grant Carnegie Mellon
  56  * the rights to redistribute these changes.
  57  */
  58 /*
  59  */
  60 /*
  61  *      File:   mach/vm_prot.h
  62  *      Author: Avadis Tevanian, Jr., Michael Wayne Young
  63  *
  64  *      Virtual memory protection definitions.
  65  *
  66  */
  67
  68 #ifndef _MACH_VM_PROT_H_
  69 #define _MACH_VM_PROT_H_
  70
  71 /*
  72  *      Types defined:
  73  *
  74  *      vm_prot_t               VM protection values.
  75  */
  76
  77 typedef int             vm_prot_t;
  78
  79 /*
  80  *      Protection values, defined as bits within the vm_prot_t type
  81  */
  82
  83 #define VM_PROT_NONE    ((vm_prot_t) 0x00)
  84
  85 #define VM_PROT_READ    ((vm_prot_t) 0x01)      /* read permission */
  86 #define VM_PROT_WRITE   ((vm_prot_t) 0x02)      /* write permission */
  87 #define VM_PROT_EXECUTE ((vm_prot_t) 0x04)      /* execute permission */
  88
  89 /*
  90  *      The default protection for newly-created virtual memory
  91  */
  92
  93 #define VM_PROT_DEFAULT (VM_PROT_READ|VM_PROT_WRITE)
  94
  95 /*
  96  *      The maximum privileges possible, for parameter checking.
  97  */
  98
  99 #define VM_PROT_ALL     (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
 100
 101 /*
 102  *      An invalid protection value.
 103  *      Used only by memory_object_lock_request to indicate no change
 104  *      to page locks.  Using -1 here is a bad idea because it
 105  *      looks like VM_PROT_ALL and then some.
 106  */
 107
 108 #define VM_PROT_NO_CHANGE       ((vm_prot_t) 0x08)
 109
 110 /*
 111  *      When a caller finds that he cannot obtain write permission on a
 112  *      mapped entry, the following flag can be used.  The entry will
 113  *      be made "needs copy" effectively copying the object (using COW),
 114  *      and write permission will be added to the maximum protections
 115  *      for the associated entry.
 116  */
 117
 118 #define VM_PROT_COPY            ((vm_prot_t) 0x10)
 119
 120
 121 /*
 122  *      Another invalid protection value.
 123  *      Used only by memory_object_data_request upon an object
 124  *      which has specified a copy_call copy strategy. It is used
 125  *      when the kernel wants a page belonging to a copy of the
 126  *      object, and is only asking the object as a result of
 127  *      following a shadow chain. This solves the race between pages
 128  *      being pushed up by the memory manager and the kernel
 129  *      walking down the shadow chain.
 130  */
 131
 132 #define VM_PROT_WANTS_COPY      ((vm_prot_t) 0x10)
 133
 134 #endif  /* _MACH_VM_PROT_H_ */