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1 | #ifndef _LTTNG_ALIGN_H |
2 | #define _LTTNG_ALIGN_H | |
3 | ||
4 | /* | |
5 | * lib/align.h | |
6 | * | |
886d51a3 | 7 | * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
6c29ebe7 | 8 | * |
886d51a3 MD |
9 | * This library is free software; you can redistribute it and/or |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; only | |
12 | * version 2.1 of the License. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
6c29ebe7 MD |
22 | */ |
23 | ||
24 | #ifdef __KERNEL__ | |
25 | ||
26 | #include <linux/types.h> | |
27 | #include "bug.h" | |
28 | ||
29 | #define ALIGN_FLOOR(x, a) __ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1) | |
30 | #define __ALIGN_FLOOR_MASK(x, mask) ((x) & ~(mask)) | |
31 | #define PTR_ALIGN_FLOOR(p, a) \ | |
32 | ((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a)) | |
33 | ||
34 | /* | |
35 | * Align pointer on natural object alignment. | |
36 | */ | |
37 | #define object_align(obj) PTR_ALIGN(obj, __alignof__(*(obj))) | |
38 | #define object_align_floor(obj) PTR_ALIGN_FLOOR(obj, __alignof__(*(obj))) | |
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 | 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 | BUILD_RUNTIME_BUG_ON((alignment) == 0 \ | |
67 | || ((alignment) & ((alignment) - 1))); \ | |
68 | (((align_drift) - (alignment)) & ((alignment) - 1); \ | |
69 | }) | |
70 | ||
71 | #endif /* __KERNEL__ */ | |
72 | ||
73 | #endif |