Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __VDSO_UNALIGNED_H
3#define __VDSO_UNALIGNED_H
4
5#include <linux/compiler_types.h>
6
7/**
8 * __get_unaligned_t - read an unaligned value from memory.
9 * @type: the type to load from the pointer.
10 * @ptr: the pointer to load from.
11 *
12 * Use memcpy to affect an unaligned type sized load avoiding undefined behavior
13 * from approaches like type punning that require -fno-strict-aliasing in order
14 * to be correct. As type may be const, use __unqual_scalar_typeof to map to a
15 * non-const type - you can't memcpy into a const type. The
16 * __get_unaligned_ctrl_type gives __unqual_scalar_typeof its required
17 * expression rather than type, a pointer is used to avoid warnings about mixing
18 * the use of 0 and NULL. The void* cast silences ubsan warnings.
19 */
20#define __get_unaligned_t(type, ptr) ({ \
21 type *__get_unaligned_ctrl_type __always_unused = NULL; \
22 __unqual_scalar_typeof(*__get_unaligned_ctrl_type) __get_unaligned_val; \
23 __builtin_memcpy(&__get_unaligned_val, (void *)(ptr), \
24 sizeof(__get_unaligned_val)); \
25 __get_unaligned_val; \
26})
27
28/**
29 * __put_unaligned_t - write an unaligned value to memory.
30 * @type: the type of the value to store.
31 * @val: the value to store.
32 * @ptr: the pointer to store to.
33 *
34 * Use memcpy to affect an unaligned type sized store avoiding undefined
35 * behavior from approaches like type punning that require -fno-strict-aliasing
36 * in order to be correct. The void* cast silences ubsan warnings.
37 */
38#define __put_unaligned_t(type, val, ptr) do { \
39 type __put_unaligned_val = (val); \
40 __builtin_memcpy((void *)(ptr), &__put_unaligned_val, \
41 sizeof(__put_unaligned_val)); \
42} while (0)
43
44#endif /* __VDSO_UNALIGNED_H */