1/*
2 * Copyright (c) 1998-2020 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_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. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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23 * Please see the License for the specific language governing rights and
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27 */
28
29#ifndef _IOGUARDPAGEMEMORYDESCRIPTOR_H
30#define _IOGUARDPAGEMEMORYDESCRIPTOR_H
31
32#include <IOKit/IOMemoryDescriptor.h>
33#include <libkern/c++/OSPtr.h>
34
35/*!
36 * @class IOGuardPageMemoryDescriptor
37 * @abstract Provides a memory descriptor that allows for variable size guard regions. Use with
38 * IOMultiMemoryDescriptor to surround other memory descriptors with guard pages.
39 */
40class IOGuardPageMemoryDescriptor : public IOGeneralMemoryDescriptor
41{
42 OSDeclareDefaultStructors(IOGuardPageMemoryDescriptor);
43
44protected:
45 virtual void free() APPLE_KEXT_OVERRIDE;
46
47 vm_offset_t _buffer;
48 vm_size_t _size;
49
50public:
51
52 /* @function withSize
53 * @discussion Create a IOGuardPageMemoryDescriptor with the specified size.
54 * @param Size of the guard region. This will be rounded up to the nearest multiple of page size.
55 * @return IOGuardPageMemoryDescriptor instance to be released by the caller, which will free the allocated
56 * virtual memory region.
57 */
58 static OSPtr<IOGuardPageMemoryDescriptor> withSize(vm_size_t size);
59
60 virtual bool initWithSize(vm_size_t size);
61
62private:
63 virtual IOReturn doMap(vm_map_t addressMap,
64 IOVirtualAddress * atAddress,
65 IOOptionBits options,
66 IOByteCount sourceOffset = 0,
67 IOByteCount length = 0 ) APPLE_KEXT_OVERRIDE;
68};
69
70#endif /* !_IOGUARDPAGEMEMORYDESCRIPTOR_H */
71