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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_VDSO_GETRANDOM_H
#define __ASM_VDSO_GETRANDOM_H
#ifndef __ASSEMBLY__
#include <asm/unistd.h>
#include <asm/vdso/vsyscall.h>
#include <vdso/datapage.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)
{
register void *buffer asm ("x0") = _buffer;
register size_t len asm ("x1") = _len;
register unsigned int flags asm ("x2") = _flags;
register long ret asm ("x0");
register long nr asm ("x8") = __NR_getrandom;
asm volatile(
" svc #0\n"
: "=r" (ret)
: "r" (buffer), "r" (len), "r" (flags), "r" (nr)
: "memory");
return ret;
}
static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
{
/*
* The RNG data is in the real VVAR data page, but if a task belongs to a time namespace
* then VVAR_DATA_PAGE_OFFSET points to the namespace-specific VVAR page and VVAR_TIMENS_
* PAGE_OFFSET points to the real VVAR page.
*/
if (IS_ENABLED(CONFIG_TIME_NS) && _vdso_data->clock_mode == VDSO_CLOCKMODE_TIMENS)
return (void *)&_vdso_rng_data + VVAR_TIMENS_PAGE_OFFSET * (1UL << CONFIG_PAGE_SHIFT);
return &_vdso_rng_data;
}
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_VDSO_GETRANDOM_H */
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