kerner-ctl: add RING_RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK
[lttng-tools.git] / src / common / align.h
1 /*
2 * Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
3 *
4 * SPDX-License-Identifier: MIT
5 *
6 */
7
8 #ifndef _LTTNG_ALIGN_H
9 #define _LTTNG_ALIGN_H
10
11 #include "bug.h"
12 #include <unistd.h>
13 #include <limits.h>
14
15 #ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE. */
16 #define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
17 #endif
18
19 #ifndef PAGE_MASK /* macOS defines its own PAGE_MASK. */
20 #define PAGE_MASK (~(PAGE_SIZE - 1))
21 #endif
22
23 #define __ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask))
24
25 #ifndef ALIGN /* macOS defines its own ALIGN. */
26 #define ALIGN(v, align) __ALIGN_MASK(v, (__typeof__(v)) (align) - 1)
27 #endif
28
29 #define __ALIGN_FLOOR_MASK(v, mask) ((v) & ~(mask))
30
31 #ifndef ALIGN_FLOOR
32 #define ALIGN_FLOOR(v, align) __ALIGN_FLOOR_MASK(v, (__typeof__(v)) (align) - 1)
33 #endif
34
35 #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
36
37 /**
38 * offset_align - Calculate the offset needed to align an object on its natural
39 * alignment towards higher addresses.
40 * @align_drift: object offset from an "alignment"-aligned address.
41 * @alignment: natural object alignment. Must be non-zero, power of 2.
42 *
43 * Returns the offset that must be added to align towards higher
44 * addresses.
45 */
46 #define offset_align(align_drift, alignment) \
47 ({ \
48 LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
49 || ((alignment) & ((alignment) - 1))); \
50 (((alignment) - (align_drift)) & ((alignment) - 1)); \
51 })
52
53 /**
54 * offset_align_floor - Calculate the offset needed to align an object
55 * on its natural alignment towards lower addresses.
56 * @align_drift: object offset from an "alignment"-aligned address.
57 * @alignment: natural object alignment. Must be non-zero, power of 2.
58 *
59 * Returns the offset that must be substracted to align towards lower addresses.
60 */
61 #define offset_align_floor(align_drift, alignment) \
62 ({ \
63 LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
64 || ((alignment) & ((alignment) - 1))); \
65 (((align_drift) - (alignment)) & ((alignment) - 1)); \
66 })
67
68 #endif /* _LTTNG_ALIGN_H */
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