osfmk/mach/vm_prot.h

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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  20  * Please see the License for the specific language governing rights and
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  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  */
  28 /*
  29  * Mach Operating System
  30  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  31  * All Rights Reserved.
  32  *
  33  * Permission to use, copy, modify and distribute this software and its
  34  * documentation is hereby granted, provided that both the copyright
  35  * notice and this permission notice appear in all copies of the
  36  * software, derivative works or modified versions, and any portions
  37  * thereof, and that both notices appear in supporting documentation.
  38  *
  39  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  40  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  41  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  42  *
  43  * Carnegie Mellon requests users of this software to return to
  44  *
  45  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  46  *  School of Computer Science
  47  *  Carnegie Mellon University
  48  *  Pittsburgh PA 15213-3890
  49  *
  50  * any improvements or extensions that they make and grant Carnegie Mellon
  51  * the rights to redistribute these changes.
  52  */
  53 /*
  54  */
  55 /*
  56  *      File:   mach/vm_prot.h
  57  *      Author: Avadis Tevanian, Jr., Michael Wayne Young
  58  *
  59  *      Virtual memory protection definitions.
  60  *
  61  */
  62
  63 #ifndef VM_PROT_H_
  64 #define VM_PROT_H_
  65
  66 /*
  67  *      Types defined:
  68  *
  69  *      vm_prot_t               VM protection values.
  70  */
  71
  72 typedef int             vm_prot_t;
  73
  74 /*
  75  *      Protection values, defined as bits within the vm_prot_t type
  76  */
  77
  78 #define VM_PROT_NONE    ((vm_prot_t) 0x00)
  79
  80 #define VM_PROT_READ    ((vm_prot_t) 0x01)      /* read permission */
  81 #define VM_PROT_WRITE   ((vm_prot_t) 0x02)      /* write permission */
  82 #define VM_PROT_EXECUTE ((vm_prot_t) 0x04)      /* execute permission */
  83
  84 /*
  85  *      The default protection for newly-created virtual memory
  86  */
  87
  88 #define VM_PROT_DEFAULT (VM_PROT_READ|VM_PROT_WRITE)
  89
  90 /*
  91  *      The maximum privileges possible, for parameter checking.
  92  */
  93
  94 #define VM_PROT_ALL     (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
  95
  96 /*
  97  *      An invalid protection value.
  98  *      Used only by memory_object_lock_request to indicate no change
  99  *      to page locks.  Using -1 here is a bad idea because it
 100  *      looks like VM_PROT_ALL and then some.
 101  */
 102 #define VM_PROT_NO_CHANGE       ((vm_prot_t) 0x08)
 103
 104 /*
 105  *      When a caller finds that he cannot obtain write permission on a
 106  *      mapped entry, the following flag can be used.  The entry will
 107  *      be made "needs copy" effectively copying the object (using COW),
 108  *      and write permission will be added to the maximum protections
 109  *      for the associated entry.
 110  */
 111 #define VM_PROT_COPY            ((vm_prot_t) 0x10)
 112
 113
 114 /*
 115  *      Another invalid protection value.
 116  *      Used only by memory_object_data_request upon an object
 117  *      which has specified a copy_call copy strategy. It is used
 118  *      when the kernel wants a page belonging to a copy of the
 119  *      object, and is only asking the object as a result of
 120  *      following a shadow chain. This solves the race between pages
 121  *      being pushed up by the memory manager and the kernel
 122  *      walking down the shadow chain.
 123  */
 124 #define VM_PROT_WANTS_COPY      ((vm_prot_t) 0x10)
 125
 126 #endif  /* VM_PROT_H_ */