freebsd-nq/sys/dev/random/probe.c
Konstantin Belousov ef9461ba0e Add support for new Intel on-CPU Bull Mountain random number
generator, found on IvyBridge and supposedly later CPUs, accessible
with RDRAND instruction.

From the Intel whitepapers and articles about Bull Mountain, it seems
that we do not need to perform post-processing of RDRAND results, like
AES-encryption of the data with random IV and keys, which was done for
Padlock. Intel claims that sanitization is performed in hardware.

Make both Padlock and Bull Mountain random generators support code
covered by kernel config options, for the benefit of people who prefer
minimal kernels. Also add the tunables to disable hardware generator
even if detected.

Reviewed by:	markm, secteam (simon)
Tested by:	bapt, Michael Moll <kvedulv@kvedulv.de>
MFC after:	3 weeks
2012-09-05 13:18:51 +00:00

94 lines
2.7 KiB
C

/*-
* Copyright (c) 2004 Mark R V Murray
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
#include "opt_cpu.h"
#endif
#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/random.h>
#include <sys/selinfo.h>
#include <sys/sysctl.h>
#if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
#include <machine/cpufunc.h>
#include <machine/cputypes.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>
#endif
#include <dev/random/randomdev.h>
#include <dev/random/randomdev_soft.h>
#if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
#ifdef PADLOCK_RNG
extern struct random_systat random_nehemiah;
#endif
#ifdef IVY_RNG
extern struct random_systat random_ivy;
#endif
#endif
void
random_ident_hardware(struct random_systat *systat)
{
/* Set default to software */
*systat = random_yarrow;
/* Then go looking for hardware */
#if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
#ifdef PADLOCK_RNG
if (via_feature_rng & VIA_HAS_RNG) {
int enable;
enable = 1;
TUNABLE_INT_FETCH("hw.nehemiah_rng_enable", &enable);
if (enable)
*systat = random_nehemiah;
}
#endif
#ifdef IVY_RNG
if (cpu_feature2 & CPUID2_RDRAND) {
int enable;
enable = 1;
TUNABLE_INT_FETCH("hw.ivy_rng_enable", &enable);
if (enable)
*systat = random_ivy;
}
#endif
#endif
}