| 1 |
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| 2 | #ifndef __VDSO_UNALIGNED_H
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| 3 | #define __VDSO_UNALIGNED_H
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| 4 |
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| 5 | #include <linux/compiler_types.h>
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| 6 |
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| 7 | |
| 8 | * __get_unaligned_t - read an unaligned value from memory.
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| 9 | * @type: the type to load from the pointer.
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| 10 | * @ptr: the pointer to load from.
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| 11 | *
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| 12 | * Use memcpy to affect an unaligned type sized load avoiding undefined behavior
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| 13 | * from approaches like type punning that require -fno-strict-aliasing in order
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| 14 | * to be correct. As type may be const, use __unqual_scalar_typeof to map to a
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| 15 | * non-const type - you can't memcpy into a const type. The
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| 16 | * __get_unaligned_ctrl_type gives __unqual_scalar_typeof its required
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| 17 | * expression rather than type, a pointer is used to avoid warnings about mixing
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| 18 | * the use of 0 and NULL. The void* cast silences ubsan warnings.
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| 19 |
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| 20 | #define __get_unaligned_t(type, ptr) ({ \
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| 21 | type *__get_unaligned_ctrl_type __always_unused = NULL; \
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| 22 | __unqual_scalar_typeof(*__get_unaligned_ctrl_type) __get_unaligned_val; \
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| 23 | __builtin_memcpy(&__get_unaligned_val, (void *)(ptr), \
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| 24 | sizeof(__get_unaligned_val)); \
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| 25 | __get_unaligned_val; \
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| 26 | })
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| 27 |
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| 28 | |
| 29 | * __put_unaligned_t - write an unaligned value to memory.
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| 30 | * @type: the type of the value to store.
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| 31 | * @val: the value to store.
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| 32 | * @ptr: the pointer to store to.
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| 33 | *
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| 34 | * Use memcpy to affect an unaligned type sized store avoiding undefined
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| 35 | * behavior from approaches like type punning that require -fno-strict-aliasing
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| 36 | * in order to be correct. The void* cast silences ubsan warnings.
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| 37 |
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| 38 | #define __put_unaligned_t(type, val, ptr) do { \
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| 39 | type __put_unaligned_val = (val); \
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| 40 | __builtin_memcpy((void *)(ptr), &__put_unaligned_val, \
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| 41 | sizeof(__put_unaligned_val)); \
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| 42 | } while (0)
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| 43 |
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| 44 | #endif
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