probe.c revision 146797 
1/*-
2 * Copyright (c) 2004 Mark R V Murray
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/sys/dev/random/probe.c 146797 2005-05-30 05:01:44Z scottl $");
30
31#include <sys/types.h>
32#include <sys/param.h>
33#include <sys/malloc.h>
34#include <sys/random.h>
35#include <sys/selinfo.h>
36#include <sys/stdint.h>
37#include <sys/sysctl.h>
38
39#if defined(__i386__) && !defined(PC98)
40#include <machine/cpufunc.h>
41#include <machine/cputypes.h>
42#endif
43
44#include <dev/random/randomdev.h>
45#include <dev/random/randomdev_soft.h>
46#include <dev/random/nehemiah.h>
47
48void
49random_ident_hardware(struct random_systat *systat)
50{
51#if defined(__i386__) && !defined(PC98)
52	u_int regs[4];
53#endif
54
55	/* Set default to software */
56	*systat = random_yarrow;
57
58	/* Then go looking for hardware */
59#if defined(__i386__) && !defined(PC98)
60	if (cpu_class < CPUCLASS_586)
61		return;
62	do_cpuid(1, regs);
63	if ((regs[0] & 0xf) >= 3) {
64		do_cpuid(0xc0000000, regs);
65		if (regs[0] == 0xc0000001) {
66			do_cpuid(0xc0000001, regs);
67			if ((regs[3] & 0x0c) == 0x0c)
68				*systat = random_nehemiah;
69		}
70	}
71#endif
72}
73