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 */ 45