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