linux/arch/x86/kernel/cpu/rdrand.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * This file is part of the Linux kernel.
 *
 * Copyright (c) 2011, Intel Corporation
 * Authors: Fenghua Yu <[email protected]>,
 *          H. Peter Anvin <[email protected]>
 */
#include <linux/printk.h>

#include <asm/processor.h>
#include <asm/archrandom.h>
#include <asm/sections.h>

/*
 * RDRAND has Built-In-Self-Test (BIST) that runs on every invocation.
 * Run the instruction a few times as a sanity check. Also make sure
 * it's not outputting the same value over and over, which has happened
 * as a result of past CPU bugs.
 *
 * If it fails, it is simple to disable RDRAND and RDSEED here.
 */

void x86_init_rdrand(struct cpuinfo_x86 *c)
{ … }