Files
linux-stable-mirror/arch/x86/include/asm/vdso/getrandom.h
Jason A. Donenfeld 6fd13b282f random: vDSO: move prototype of arch chacha function to vdso/getrandom.h
Having the prototype for __arch_chacha20_blocks_nostack in
arch/x86/include/asm/vdso/getrandom.h meant that the prototype and large
doc comment were cloned by every architecture, which has been causing
unnecessary churn. Instead move it into include/vdso/getrandom.h, where
it can be shared by all archs implementing it.

As a side bonus, this then lets us use that prototype in the
vdso_test_chacha self test, to ensure that it matches the source, and
indeed doing so turned up some inconsistencies, which are rectified
here.

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2024-09-13 17:28:35 +02:00

43 lines
1.2 KiB
C

/* 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 __ASSEMBLY__
#include <asm/unistd.h>
#include <asm/vvar.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;
}
#define __vdso_rng_data (VVAR(_vdso_rng_data))
static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
{
if (IS_ENABLED(CONFIG_TIME_NS) && __vdso_data->clock_mode == VDSO_CLOCKMODE_TIMENS)
return (void *)&__vdso_rng_data + ((void *)&__timens_vdso_data - (void *)&__vdso_data);
return &__vdso_rng_data;
}
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_VDSO_GETRANDOM_H */