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  * 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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * @OSF_COPYRIGHT@
  25  */
  26 /*
  27  * Mach Operating System
  28  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  29  * All Rights Reserved.
  30  *
  31  * Permission to use, copy, modify and distribute this software and its
  32  * documentation is hereby granted, provided that both the copyright
  33  * notice and this permission notice appear in all copies of the
  34  * software, derivative works or modified versions, and any portions
  35  * thereof, and that both notices appear in supporting documentation.
  36  *
  37  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  38  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  39  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  40  *
  41  * Carnegie Mellon requests users of this software to return to
  42  *
  43  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  44  *  School of Computer Science
  45  *  Carnegie Mellon University
  46  *  Pittsburgh PA 15213-3890
  47  *
  48  * any improvements or extensions that they make and grant Carnegie Mellon
  49  * the rights to redistribute these changes.
  50  */
  51 /*
  52  */
  53 /*
  54  *      File:   mach/vm_prot.h
  55  *      Author: Avadis Tevanian, Jr., Michael Wayne Young
  56  *
  57  *      Virtual memory protection definitions.
  58  *
  59  */
  60
  61 #ifndef _MACH_VM_PROT_H_
  62 #define _MACH_VM_PROT_H_
  63
  64 /*
  65  *      Types defined:
  66  *
  67  *      vm_prot_t               VM protection values.
  68  */
  69
  70 typedef int             vm_prot_t;
  71
  72 /*
  73  *      Protection values, defined as bits within the vm_prot_t type
  74  */
  75
  76 #define VM_PROT_NONE    ((vm_prot_t) 0x00)
  77
  78 #define VM_PROT_READ    ((vm_prot_t) 0x01)      /* read permission */
  79 #define VM_PROT_WRITE   ((vm_prot_t) 0x02)      /* write permission */
  80 #define VM_PROT_EXECUTE ((vm_prot_t) 0x04)      /* execute permission */
  81
  82 /*
  83  *      The default protection for newly-created virtual memory
  84  */
  85
  86 #define VM_PROT_DEFAULT (VM_PROT_READ|VM_PROT_WRITE)
  87
  88 /*
  89  *      The maximum privileges possible, for parameter checking.
  90  */
  91
  92 #define VM_PROT_ALL     (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
  93
  94 /*
  95  *      An invalid protection value.
  96  *      Used only by memory_object_lock_request to indicate no change
  97  *      to page locks.  Using -1 here is a bad idea because it
  98  *      looks like VM_PROT_ALL and then some.
  99  */
 100
 101 #define VM_PROT_NO_CHANGE       ((vm_prot_t) 0x08)
 102
 103 /*
 104  *      When a caller finds that he cannot obtain write permission on a
 105  *      mapped entry, the following flag can be used.  The entry will
 106  *      be made "needs copy" effectively copying the object (using COW),
 107  *      and write permission will be added to the maximum protections
 108  *      for the associated entry.
 109  */
 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
 125 #define VM_PROT_WANTS_COPY      ((vm_prot_t) 0x10)
 126
 127 #endif  /* _MACH_VM_PROT_H_ */