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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Kernel interface for the s390 arch_random_* functions
4 *
5 * Copyright IBM Corp. 2017
6 *
7 * Author: Harald Freudenberger <freude@de.ibm.com>
8 *
9 */
10
11#ifndef _ASM_S390_ARCHRANDOM_H
12#define _ASM_S390_ARCHRANDOM_H
13
14#ifdef CONFIG_ARCH_RANDOM
15
16#include <linux/static_key.h>
17#include <linux/atomic.h>
18#include <asm/cpacf.h>
19
20DECLARE_STATIC_KEY_FALSE(s390_arch_random_available);
21extern atomic64_t s390_arch_random_counter;
22
23static void s390_arch_random_generate(u8 *buf, unsigned int nbytes)
24{
25 cpacf_trng(NULL, 0, buf, nbytes);
26 atomic64_add(nbytes, &s390_arch_random_counter);
27}
28
29static inline bool arch_has_random(void)
30{
31 return false;
32}
33
34static inline bool arch_has_random_seed(void)
35{
36 if (static_branch_likely(&s390_arch_random_available))
37 return true;
38 return false;
39}
40
41static inline bool arch_get_random_long(unsigned long *v)
42{
43 return false;
44}
45
46static inline bool arch_get_random_int(unsigned int *v)
47{
48 return false;
49}
50
51static inline bool arch_get_random_seed_long(unsigned long *v)
52{
53 if (static_branch_likely(&s390_arch_random_available)) {
54 s390_arch_random_generate((u8 *)v, sizeof(*v));
55 return true;
56 }
57 return false;
58}
59
60static inline bool arch_get_random_seed_int(unsigned int *v)
61{
62 if (static_branch_likely(&s390_arch_random_available)) {
63 s390_arch_random_generate((u8 *)v, sizeof(*v));
64 return true;
65 }
66 return false;
67}
68
69#endif /* CONFIG_ARCH_RANDOM */
70#endif /* _ASM_S390_ARCHRANDOM_H */