1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #ifndef __ASM_VDSO_GETRANDOM_H
4 #define __ASM_VDSO_GETRANDOM_H
5
6 #ifndef __ASSEMBLY__
7
8 #include <vdso/datapage.h>
9 #include <asm/vdso/vsyscall.h>
10 #include <asm/syscall.h>
11 #include <asm/unistd.h>
12 #include <asm/page.h>
13
14 /**
15 * getrandom_syscall - Invoke the getrandom() syscall.
16 * @buffer: Destination buffer to fill with random bytes.
17 * @len: Size of @buffer in bytes.
18 * @flags: Zero or more GRND_* flags.
19 * Returns: The number of random bytes written to @buffer, or a negative value indicating an error.
20 */
21 static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
22 {
23 return syscall3(__NR_getrandom, (long)buffer, (long)len, (long)flags);
24 }
25
26 static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
27 {
28 /*
29 * The RNG data is in the real VVAR data page, but if a task belongs to a time namespace
30 * then VVAR_DATA_PAGE_OFFSET points to the namespace-specific VVAR page and VVAR_TIMENS_
31 * PAGE_OFFSET points to the real VVAR page.
32 */
33 if (IS_ENABLED(CONFIG_TIME_NS) && _vdso_data->clock_mode == VDSO_CLOCKMODE_TIMENS)
34 return (void *)&_vdso_rng_data + VVAR_TIMENS_PAGE_OFFSET * PAGE_SIZE;
35 return &_vdso_rng_data;
36 }
37
38 #endif /* !__ASSEMBLY__ */
39
40 #endif /* __ASM_VDSO_GETRANDOM_H */
41
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