FreeBSD/Linux Kernel Cross Reference
sys/dev/random/probe.c
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: releng/8.4/sys/dev/random/probe.c 260647 2014-01-14 19:42:28Z delphij $");
30
31 #if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
32 #include "opt_cpu.h"
33 #endif
34
35 #include <sys/types.h>
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
39 #include <sys/malloc.h>
40 #include <sys/random.h>
41 #include <sys/selinfo.h>
42 #include <sys/sysctl.h>
43
44 #if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
45 #include <machine/cpufunc.h>
46 #include <machine/cputypes.h>
47 #include <machine/md_var.h>
48 #include <machine/specialreg.h>
49 #endif
50
51 #include <dev/random/randomdev.h>
52 #include <dev/random/randomdev_soft.h>
53
54 #if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
55 #ifdef PADLOCK_RNG
56 extern struct random_systat random_nehemiah;
57 #endif
58 #ifdef RDRAND_RNG
59 extern struct random_systat random_ivy;
60 #endif
61 #endif
62
63 void
64 random_ident_hardware(struct random_systat *systat)
65 {
66
67 /* Set default to software */
68 *systat = random_yarrow;
69
70 /* Then go looking for hardware */
71 #if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
72 #ifdef PADLOCK_RNG
73 if (via_feature_rng & VIA_HAS_RNG) {
74 int enable;
75
76 enable = 0;
77 TUNABLE_INT_FETCH("hw.nehemiah_rng_enable", &enable);
78 if (enable)
79 *systat = random_nehemiah;
80 }
81 #endif
82 #ifdef RDRAND_RNG
83 if (cpu_feature2 & CPUID2_RDRAND) {
84 int enable;
85
86 enable = 0;
87 TUNABLE_INT_FETCH("hw.ivy_rng_enable", &enable);
88 if (enable)
89 *systat = random_ivy;
90 }
91 #endif
92 #endif
93 }
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