| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | /* |
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| 3 | * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. |
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| 4 | */ |
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| 5 | #ifndef __ASM_VDSO_GETRANDOM_H |
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| 6 | #define __ASM_VDSO_GETRANDOM_H |
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| 7 | |
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| 8 | #ifndef __ASSEMBLER__ |
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| 9 | |
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| 10 | #include <asm/unistd.h> |
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| 11 | |
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| 12 | /** |
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| 13 | * getrandom_syscall - Invoke the getrandom() syscall. |
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| 14 | * @buffer: Destination buffer to fill with random bytes. |
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| 15 | * @len: Size of @buffer in bytes. |
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| 16 | * @flags: Zero or more GRND_* flags. |
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| 17 | * Returns: The number of random bytes written to @buffer, or a negative value indicating an error. |
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| 18 | */ |
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| 19 | static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags) |
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| 20 | { |
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| 21 | long ret; |
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| 22 | |
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| 23 | asm ("syscall" : "=a" (ret) : |
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| 24 | "0" (__NR_getrandom), "D" (buffer), "S" (len), "d" (flags) : |
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| 25 | "rcx" , "r11" , "memory" ); |
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| 26 | |
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| 27 | return ret; |
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| 28 | } |
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| 29 | |
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| 30 | #endif /* !__ASSEMBLER__ */ |
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| 31 | |
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| 32 | #endif /* __ASM_VDSO_GETRANDOM_H */ |
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| 33 | |
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