xref: /dflybsd-src/sys/dev/crypto/padlock/padlock_rng.c (revision 4190f1a0ae387f9adb9b122c1b4f1b746c26978d)
1*4190f1a0SAlex Hornung /*
2*4190f1a0SAlex Hornung  * Copyright (c) 2011 Alex Hornung <alex@alexhornung.com>.
3*4190f1a0SAlex Hornung  * All rights reserved.
4*4190f1a0SAlex Hornung  *
5*4190f1a0SAlex Hornung  * Redistribution and use in source and binary forms, with or without
6*4190f1a0SAlex Hornung  * modification, are permitted provided that the following conditions
7*4190f1a0SAlex Hornung  * are met:
8*4190f1a0SAlex Hornung  *
9*4190f1a0SAlex Hornung  * 1. Redistributions of source code must retain the above copyright
10*4190f1a0SAlex Hornung  *    notice, this list of conditions and the following disclaimer.
11*4190f1a0SAlex Hornung  * 2. Redistributions in binary form must reproduce the above copyright
12*4190f1a0SAlex Hornung  *    notice, this list of conditions and the following disclaimer in
13*4190f1a0SAlex Hornung  *    the documentation and/or other materials provided with the
14*4190f1a0SAlex Hornung  *    distribution.
15*4190f1a0SAlex Hornung  *
16*4190f1a0SAlex Hornung  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17*4190f1a0SAlex Hornung  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18*4190f1a0SAlex Hornung  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
19*4190f1a0SAlex Hornung  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
20*4190f1a0SAlex Hornung  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
21*4190f1a0SAlex Hornung  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
22*4190f1a0SAlex Hornung  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23*4190f1a0SAlex Hornung  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
24*4190f1a0SAlex Hornung  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25*4190f1a0SAlex Hornung  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
26*4190f1a0SAlex Hornung  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27*4190f1a0SAlex Hornung  * SUCH DAMAGE.
28*4190f1a0SAlex Hornung  */
29*4190f1a0SAlex Hornung #include <sys/param.h>
30*4190f1a0SAlex Hornung #include <sys/systm.h>
31*4190f1a0SAlex Hornung #include <sys/kernel.h>
32*4190f1a0SAlex Hornung #include <sys/module.h>
33*4190f1a0SAlex Hornung #include <sys/malloc.h>
34*4190f1a0SAlex Hornung #include <sys/libkern.h>
35*4190f1a0SAlex Hornung #include <sys/random.h>
36*4190f1a0SAlex Hornung 
37*4190f1a0SAlex Hornung #include <dev/crypto/padlock/padlock.h>
38*4190f1a0SAlex Hornung 
39*4190f1a0SAlex Hornung static int random_count = 16;
40*4190f1a0SAlex Hornung 
41*4190f1a0SAlex Hornung static __inline void
42*4190f1a0SAlex Hornung padlock_rng(int *out, size_t count)
43*4190f1a0SAlex Hornung {
44*4190f1a0SAlex Hornung 	unsigned int status;
45*4190f1a0SAlex Hornung 
46*4190f1a0SAlex Hornung 	/*
47*4190f1a0SAlex Hornung 	 * xstore-rng:
48*4190f1a0SAlex Hornung 	 * eax: (output) RNG status word
49*4190f1a0SAlex Hornung 	 * ecx: (input)  rep. count
50*4190f1a0SAlex Hornung 	 * edx: (input)  quality factor (0-3)
51*4190f1a0SAlex Hornung 	 * edi: (input)  buffer for random data
52*4190f1a0SAlex Hornung 	 */
53*4190f1a0SAlex Hornung 	__asm __volatile(
54*4190f1a0SAlex Hornung 		"pushf			\n\t"
55*4190f1a0SAlex Hornung 		"popf			\n\t"
56*4190f1a0SAlex Hornung 		"rep			\n\t"
57*4190f1a0SAlex Hornung 		".byte  0x0f, 0xa7, 0xc0"
58*4190f1a0SAlex Hornung 			: "=a" (status)
59*4190f1a0SAlex Hornung 			: "d" (2), "D" (out), "c" (count*sizeof(*out))
60*4190f1a0SAlex Hornung 			: "cc", "memory"
61*4190f1a0SAlex Hornung 	);
62*4190f1a0SAlex Hornung }
63*4190f1a0SAlex Hornung 
64*4190f1a0SAlex Hornung static void
65*4190f1a0SAlex Hornung padlock_rng_harvest(void *arg)
66*4190f1a0SAlex Hornung {
67*4190f1a0SAlex Hornung 	struct padlock_softc *sc = arg;
68*4190f1a0SAlex Hornung 	int randomness[128];
69*4190f1a0SAlex Hornung 	int *arandomness; /* randomness aligned */
70*4190f1a0SAlex Hornung 	int i;
71*4190f1a0SAlex Hornung 
72*4190f1a0SAlex Hornung 	arandomness = PADLOCK_ALIGN(randomness);
73*4190f1a0SAlex Hornung 	padlock_rng(arandomness, random_count);
74*4190f1a0SAlex Hornung 
75*4190f1a0SAlex Hornung 	for (i = 0; i < random_count; i++)
76*4190f1a0SAlex Hornung 		add_true_randomness(arandomness[i]);
77*4190f1a0SAlex Hornung 
78*4190f1a0SAlex Hornung 	callout_reset(&sc->sc_rng_co, sc->sc_rng_ticks,
79*4190f1a0SAlex Hornung 	    padlock_rng_harvest, sc);
80*4190f1a0SAlex Hornung }
81*4190f1a0SAlex Hornung 
82*4190f1a0SAlex Hornung void
83*4190f1a0SAlex Hornung padlock_rng_init(struct padlock_softc *sc)
84*4190f1a0SAlex Hornung {
85*4190f1a0SAlex Hornung 	if (hz > 100)
86*4190f1a0SAlex Hornung 		sc->sc_rng_ticks = hz/100;
87*4190f1a0SAlex Hornung 	else
88*4190f1a0SAlex Hornung 		sc->sc_rng_ticks = 1;
89*4190f1a0SAlex Hornung 
90*4190f1a0SAlex Hornung 	callout_init_mp(&sc->sc_rng_co);
91*4190f1a0SAlex Hornung 	callout_reset(&sc->sc_rng_co, sc->sc_rng_ticks,
92*4190f1a0SAlex Hornung 	    padlock_rng_harvest, sc);
93*4190f1a0SAlex Hornung }
94*4190f1a0SAlex Hornung 
95*4190f1a0SAlex Hornung void
96*4190f1a0SAlex Hornung padlock_rng_uninit(struct padlock_softc *sc)
97*4190f1a0SAlex Hornung {
98*4190f1a0SAlex Hornung 	callout_stop(&sc->sc_rng_co);
99*4190f1a0SAlex Hornung }
100*4190f1a0SAlex Hornung 
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