1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Kernel interface for the s390 arch_random_* functions
4 *
5 * Copyright IBM Corp. 2017, 2022
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/preempt.h>
18#include <linux/atomic.h>
19#include <asm/cpacf.h>
20
21DECLARE_STATIC_KEY_FALSE(s390_arch_random_available);
22extern atomic64_t s390_arch_random_counter;
23
24static inline bool __must_check arch_get_random_long(unsigned long *v)
25{
26	return false;
27}
28
29static inline bool __must_check arch_get_random_int(unsigned int *v)
30{
31	return false;
32}
33
34static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
35{
36	if (static_branch_likely(&s390_arch_random_available) &&
37	    in_task()) {
38		cpacf_trng(NULL, 0, (u8 *)v, sizeof(*v));
39		atomic64_add(sizeof(*v), &s390_arch_random_counter);
40		return true;
41	}
42	return false;
43}
44
45static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
46{
47	if (static_branch_likely(&s390_arch_random_available) &&
48	    in_task()) {
49		cpacf_trng(NULL, 0, (u8 *)v, sizeof(*v));
50		atomic64_add(sizeof(*v), &s390_arch_random_counter);
51		return true;
52	}
53	return false;
54}
55
56#endif /* CONFIG_ARCH_RANDOM */
57#endif /* _ASM_S390_ARCHRANDOM_H */
58