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// SPDX-License-Identifier: GPL-2.0
/*
* s390 arch random implementation.
*
* Copyright IBM Corp. 2017
* Author(s): Harald Freudenberger <freude@de.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (version 2 only)
* as published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/atomic.h>
#include <linux/random.h>
#include <linux/static_key.h>
#include <asm/cpacf.h>
DEFINE_STATIC_KEY_FALSE(s390_arch_random_available);
atomic64_t s390_arch_random_counter = ATOMIC64_INIT(0);
EXPORT_SYMBOL(s390_arch_random_counter);
static int __init s390_arch_random_init(void)
{
/* check if subfunction CPACF_PRNO_TRNG is available */
if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG))
static_branch_enable(&s390_arch_random_available);
return 0;
}
arch_initcall(s390_arch_random_init);
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