projects / lttng-ust.git / blame
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1 | #ifndef _UST_ALIGN_H |
| 2 | #define _UST_ALIGN_H | |
| 3 | ||
| 4 | /* | |
| 4318ae1b | 5 | * lttng/align.h |
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6 | * |
| 7 | * (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
| 8 | * | |
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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: | |
| a60d70e6 | 15 | * |
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16 | * The above copyright notice and this permission notice shall be included in |
| 17 | * all copies or substantial portions of the Software. | |
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18 | */ |
| 19 | ||
| 4318ae1b | 20 | #include <lttng/bug.h> |
| 993e8a49 | 21 | #include <unistd.h> |
| 8c4127c5 | 22 | |
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23 | #define PAGE_SIZE sysconf(_SC_PAGE_SIZE) |
| 24 | #define PAGE_MASK (~(PAGE_SIZE - 1)) | |
| 25 | #define __ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask)) | |
| 2e349edd | 26 | #define ALIGN(v, align) __ALIGN_MASK(v, (__typeof__(v)) (align) - 1) |
| 993e8a49 | 27 | #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE) |
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28 | |
| 29 | /** | |
| 30 | * offset_align - Calculate the offset needed to align an object on its natural | |
| 31 | * alignment towards higher addresses. | |
| 32 | * @align_drift: object offset from an "alignment"-aligned address. | |
| 33 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
| 34 | * | |
| 35 | * Returns the offset that must be added to align towards higher | |
| 36 | * addresses. | |
| 37 | */ | |
| 38 | #define offset_align(align_drift, alignment) \ | |
| 39 | ({ \ | |
| 3f12fcef | 40 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ |
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41 | || ((alignment) & ((alignment) - 1))); \ |
| 42 | (((alignment) - (align_drift)) & ((alignment) - 1)); \ | |
| 43 | }) | |
| 44 | ||
| 45 | /** | |
| 46 | * offset_align_floor - Calculate the offset needed to align an object | |
| 47 | * on its natural alignment towards lower addresses. | |
| 48 | * @align_drift: object offset from an "alignment"-aligned address. | |
| 49 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
| 50 | * | |
| 51 | * Returns the offset that must be substracted to align towards lower addresses. | |
| 52 | */ | |
| 53 | #define offset_align_floor(align_drift, alignment) \ | |
| 54 | ({ \ | |
| 3f12fcef | 55 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ |
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56 | || ((alignment) & ((alignment) - 1))); \ |
| 57 | (((align_drift) - (alignment)) & ((alignment) - 1); \ | |
| 58 | }) | |
| 59 | ||
| 60 | #endif /* _UST_ALIGN_H */ |