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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2
3#ifndef __ASM_VDSO_GETRANDOM_H
4#define __ASM_VDSO_GETRANDOM_H
5
6#ifndef __ASSEMBLER__
7
8#include <asm/unistd.h>
9#include <asm/vdso/vsyscall.h>
10#include <vdso/datapage.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 register void *buffer asm ("x0") = _buffer;
22 register size_t len asm ("x1") = _len;
23 register unsigned int flags asm ("x2") = _flags;
24 register long ret asm ("x0");
25 register long nr asm ("x8") = __NR_getrandom;
26
27 asm volatile(
28 " svc #0\n"
29 : "=r" (ret)
30 : "r" (buffer), "r" (len), "r" (flags), "r" (nr)
31 : "memory");
32
33 return ret;
34}
35
36#endif /* !__ASSEMBLER__ */
37
38#endif /* __ASM_VDSO_GETRANDOM_H */