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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#ifndef __ASM_VDSO_GETRANDOM_H
#define __ASM_VDSO_GETRANDOM_H
#ifndef __ASSEMBLER__
#include <asm/unistd.h>
/**
* getrandom_syscall - Invoke the getrandom() syscall.
* @buffer: Destination buffer to fill with random bytes.
* @len: Size of @buffer in bytes.
* @flags: Zero or more GRND_* flags.
* Returns: The number of random bytes written to @buffer, or a negative value indicating an error.
*/
static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
{
long ret;
asm ("syscall" : "=a" (ret) :
"0" (__NR_getrandom), "D" (buffer), "S" (len), "d" (flags) :
"rcx", "r11", "memory");
return ret;
}
#endif /* !__ASSEMBLER__ */
#endif /* __ASM_VDSO_GETRANDOM_H */
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