2 * Copyright (c) 2013 The FreeBSD Foundation
3 * Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
4 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
7 * Portions of this software were developed by Konstantin Belousov
8 * under sponsorship from the FreeBSD Foundation.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer
15 * in this position and unchanged.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
36 #include <sys/param.h>
37 #include <sys/kernel.h>
39 #include <sys/malloc.h>
40 #include <sys/module.h>
41 #include <sys/random.h>
42 #include <sys/selinfo.h>
43 #include <sys/systm.h>
45 #include <machine/md_var.h>
46 #include <machine/specialreg.h>
48 #include <dev/random/randomdev.h>
49 #include <dev/random/randomdev_soft.h>
50 #include <dev/random/random_harvestq.h>
51 #include <dev/random/live_entropy_sources.h>
52 #include <dev/random/random_adaptors.h>
54 #define RETRY_COUNT 10
56 static int random_ivy_read(void *, int);
58 static struct random_hardware_source random_ivy = {
59 .ident = "Hardware, Intel Secure Key RNG",
60 .source = RANDOM_PURE_RDRAND,
61 .read = random_ivy_read
65 ivy_rng_store(long *buf)
74 "rdrand %2\n\t" /* read randomness into tmp */
75 "jb 2f\n\t" /* CF is set on success, exit retry loop */
76 "dec %0\n\t" /* otherwise, retry-- */
77 "jne 1b\n\t" /* and loop if retries are not exhausted */
78 "jmp 3f\n" /* failure, retry is 0, used as return value */
80 "mov %2,%1\n\t" /* *buf = tmp */
82 : "+q" (retry), "=m" (*buf), "=q" (tmp) : : "cc");
84 #else /* __GNUCLIKE_ASM */
90 random_ivy_read(void *buf, int c)
95 KASSERT(c % sizeof(long) == 0, ("partial read %d", c));
96 for (b = buf, count = c; count > 0; count -= sizeof(long), b++) {
97 if (ivy_rng_store(b) == 0)
104 rdrand_modevent(module_t mod, int type, void *unused)
110 if (cpu_feature2 & CPUID2_RDRAND)
111 live_entropy_source_register(&random_ivy);
116 printf("%s: RDRAND is not present\n",
121 if (cpu_feature2 & CPUID2_RDRAND)
122 live_entropy_source_deregister(&random_ivy);
137 LIVE_ENTROPY_SRC_MODULE(random_rdrand, rdrand_modevent, 1);