archrandom.h

 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#include <linux/static_key.h>
15#include <linux/preempt.h>
16#include <linux/atomic.h>
17#include <asm/cpacf.h>
18
19DECLARE_STATIC_KEY_FALSE(s390_arch_random_available);
20extern atomic64_t s390_arch_random_counter;
21
22static inline size_t __must_check arch_get_random_longs(unsigned long *v, size_t max_longs)
23{
24	return 0;
25}
26
27static inline size_t __must_check arch_get_random_seed_longs(unsigned long *v, size_t max_longs)
28{
29	if (static_branch_likely(&s390_arch_random_available) &&
30	    in_task()) {
31		cpacf_trng(NULL, 0, (u8 *)v, max_longs * sizeof(*v));
32		atomic64_add(max_longs * sizeof(*v), &s390_arch_random_counter);
33		return max_longs;
34	}
35	return 0;
36}
37
38#endif /* _ASM_S390_ARCHRANDOM_H */