Support LTTNG_KERNEL_SESSION_SET_CREATION_NAME of lttng-modules
[lttng-tools.git] / src / common / align.h
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1#ifndef _LTTNG_ALIGN_H
2#define _LTTNG_ALIGN_H
3
4/*
5 * align.h
6 *
7 * (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 */
19
8564ccbd 20#include "bug.h"
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21#include <unistd.h>
22#include <limits.h>
23
d575a7f8 24#ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE. */
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25#define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
26#endif
27
d575a7f8 28#ifndef PAGE_MASK /* macOS defines its own PAGE_MASK. */
953192ba 29#define PAGE_MASK (~(PAGE_SIZE - 1))
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30#endif
31
953192ba 32#define __ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask))
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33
34#ifndef ALIGN /* macOS defines its own ALIGN. */
953192ba 35#define ALIGN(v, align) __ALIGN_MASK(v, (__typeof__(v)) (align) - 1)
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36#endif
37
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38#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
39
40/**
41 * offset_align - Calculate the offset needed to align an object on its natural
42 * alignment towards higher addresses.
43 * @align_drift: object offset from an "alignment"-aligned address.
44 * @alignment: natural object alignment. Must be non-zero, power of 2.
45 *
46 * Returns the offset that must be added to align towards higher
47 * addresses.
48 */
49#define offset_align(align_drift, alignment) \
50 ({ \
51 LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
52 || ((alignment) & ((alignment) - 1))); \
53 (((alignment) - (align_drift)) & ((alignment) - 1)); \
54 })
55
56/**
57 * offset_align_floor - Calculate the offset needed to align an object
58 * on its natural alignment towards lower addresses.
59 * @align_drift: object offset from an "alignment"-aligned address.
60 * @alignment: natural object alignment. Must be non-zero, power of 2.
61 *
62 * Returns the offset that must be substracted to align towards lower addresses.
63 */
64#define offset_align_floor(align_drift, alignment) \
65 ({ \
66 LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
67 || ((alignment) & ((alignment) - 1))); \
d07ceecd 68 (((align_drift) - (alignment)) & ((alignment) - 1)); \
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69 })
70
71#endif /* _LTTNG_ALIGN_H */
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