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  * The contents of this file constitute Original Code as defined in and
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   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
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  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52 /*
  53  *      File:   mach/vm_prot.h
  54  *      Author: Avadis Tevanian, Jr., Michael Wayne Young
  55  *
  56  *      Virtual memory protection definitions.
  57  *
  58  */
  59
  60 #ifndef _MACH_VM_PROT_H_
  61 #define _MACH_VM_PROT_H_
  62
  63 /*
  64  *      Types defined:
  65  *
  66  *      vm_prot_t               VM protection values.
  67  */
  68
  69 typedef int             vm_prot_t;
  70
  71 /*
  72  *      Protection values, defined as bits within the vm_prot_t type
  73  */
  74
  75 #define VM_PROT_NONE    ((vm_prot_t) 0x00)
  76
  77 #define VM_PROT_READ    ((vm_prot_t) 0x01)      /* read permission */
  78 #define VM_PROT_WRITE   ((vm_prot_t) 0x02)      /* write permission */
  79 #define VM_PROT_EXECUTE ((vm_prot_t) 0x04)      /* execute permission */
  80
  81 /*
  82  *      The default protection for newly-created virtual memory
  83  */
  84
  85 #define VM_PROT_DEFAULT (VM_PROT_READ|VM_PROT_WRITE)
  86
  87 /*
  88  *      The maximum privileges possible, for parameter checking.
  89  */
  90
  91 #define VM_PROT_ALL     (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
  92
  93 /*
  94  *      An invalid protection value.
  95  *      Used only by memory_object_lock_request to indicate no change
  96  *      to page locks.  Using -1 here is a bad idea because it
  97  *      looks like VM_PROT_ALL and then some.
  98  */
  99
 100 #define VM_PROT_NO_CHANGE       ((vm_prot_t) 0x08)
 101
 102 /*
 103  *      When a caller finds that he cannot obtain write permission on a
 104  *      mapped entry, the following flag can be used.  The entry will
 105  *      be made "needs copy" effectively copying the object (using COW),
 106  *      and write permission will be added to the maximum protections
 107  *      for the associated entry.
 108  */
 109
 110 #define VM_PROT_COPY            ((vm_prot_t) 0x10)
 111
 112
 113 /*
 114  *      Another invalid protection value.
 115  *      Used only by memory_object_data_request upon an object
 116  *      which has specified a copy_call copy strategy. It is used
 117  *      when the kernel wants a page belonging to a copy of the
 118  *      object, and is only asking the object as a result of
 119  *      following a shadow chain. This solves the race between pages
 120  *      being pushed up by the memory manager and the kernel
 121  *      walking down the shadow chain.
 122  */
 123
 124 #define VM_PROT_WANTS_COPY      ((vm_prot_t) 0x10)
 125
 126 #endif  /* _MACH_VM_PROT_H_ */