Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
4 */
5#ifndef __ASM_VDSO_GETRANDOM_H
6#define __ASM_VDSO_GETRANDOM_H
7
8#ifndef __ASSEMBLER__
9
10#include <asm/unistd.h>
11
12/**
13 * getrandom_syscall - Invoke the getrandom() syscall.
14 * @buffer: Destination buffer to fill with random bytes.
15 * @len: Size of @buffer in bytes.
16 * @flags: Zero or more GRND_* flags.
17 * Returns: The number of random bytes written to @buffer, or a negative value indicating an error.
18 */
19static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
20{
21 long ret;
22
23 asm ("syscall" : "=a" (ret) :
24 "0" (__NR_getrandom), "D" (buffer), "S" (len), "d" (flags) :
25 "rcx", "r11", "memory");
26
27 return ret;
28}
29
30#endif /* !__ASSEMBLER__ */
31
32#endif /* __ASM_VDSO_GETRANDOM_H */