184615Snyan/*-
284615Snyan * Copyright (c) 2013 The FreeBSD Foundation
384615Snyan * Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
484615Snyan * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
584615Snyan * All rights reserved.
684615Snyan *
784615Snyan * Portions of this software were developed by Konstantin Belousov
884615Snyan * under sponsorship from the FreeBSD Foundation.
984615Snyan *
1084615Snyan * Redistribution and use in source and binary forms, with or without
1184615Snyan * modification, are permitted provided that the following conditions
1284615Snyan * are met:
1384615Snyan * 1. Redistributions of source code must retain the above copyright
1484615Snyan *    notice, this list of conditions and the following disclaimer
1584615Snyan *    in this position and unchanged.
1684615Snyan * 2. Redistributions in binary form must reproduce the above copyright
1784615Snyan *    notice, this list of conditions and the following disclaimer in the
1884615Snyan *    documentation and/or other materials provided with the distribution.
1984615Snyan *
2084615Snyan * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
2184615Snyan * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
2284615Snyan * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
2384615Snyan * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
2484615Snyan * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
2584615Snyan * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
2684615Snyan * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
2784615Snyan * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
2884615Snyan * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
2984615Snyan * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
3084615Snyan *
3184615Snyan */
3284615Snyan
3384615Snyan#include <sys/cdefs.h>
3484615Snyan__FBSDID("$FreeBSD$");
3584615Snyan
3684615Snyan#include <sys/param.h>
3784615Snyan#include <sys/kernel.h>
3884615Snyan#include <sys/lock.h>
3984615Snyan#include <sys/malloc.h>
4084615Snyan#include <sys/module.h>
4184615Snyan#include <sys/random.h>
4284615Snyan#include <sys/selinfo.h>
4384615Snyan#include <sys/systm.h>
4484615Snyan
4584615Snyan#include <machine/md_var.h>
4690762Snyan#include <machine/specialreg.h>
4784615Snyan
4884615Snyan#include <dev/random/randomdev.h>
4990762Snyan#include <dev/random/randomdev_soft.h>
5090762Snyan#include <dev/random/random_harvestq.h>
5184615Snyan#include <dev/random/live_entropy_sources.h>
5284615Snyan#include <dev/random/random_adaptors.h>
5384615Snyan
5484615Snyan#define	RETRY_COUNT	10
5584615Snyan
5684615Snyanstatic int random_ivy_read(void *, int);
5784615Snyan
5884615Snyanstatic struct random_hardware_source random_ivy = {
5984615Snyan	.ident = "Hardware, Intel Secure Key RNG",
6084615Snyan	.source = RANDOM_PURE_RDRAND,
6184615Snyan	.read = random_ivy_read
6284615Snyan};
6384615Snyan
6484615Snyanstatic inline int
6584615Snyanivy_rng_store(long *buf)
6684615Snyan{
6784615Snyan#ifdef __GNUCLIKE_ASM
6884615Snyan	long tmp;
6984615Snyan	int retry;
7084615Snyan
7184615Snyan	retry = RETRY_COUNT;
7284615Snyan	__asm __volatile(
7384615Snyan	    "1:\n\t"
7484615Snyan	    "rdrand	%2\n\t"	/* read randomness into tmp */
7584615Snyan	    "jb		2f\n\t" /* CF is set on success, exit retry loop */
7684615Snyan	    "dec	%0\n\t" /* otherwise, retry-- */
7784615Snyan	    "jne	1b\n\t" /* and loop if retries are not exhausted */
7884615Snyan	    "jmp	3f\n"	/* failure, retry is 0, used as return value */
7984615Snyan	    "2:\n\t"
8084615Snyan	    "mov	%2,%1\n\t" /* *buf = tmp */
8184615Snyan	    "3:"
8284615Snyan	    : "+q" (retry), "=m" (*buf), "=q" (tmp) : : "cc");
8384615Snyan	return (retry);
8484615Snyan#else /* __GNUCLIKE_ASM */
8584615Snyan	return (0);
8684615Snyan#endif
8784615Snyan}
8884615Snyan
8984615Snyanstatic int
9084615Snyanrandom_ivy_read(void *buf, int c)
9184615Snyan{
9284615Snyan	long *b;
9384615Snyan	int count;
9484615Snyan
9584615Snyan	KASSERT(c % sizeof(long) == 0, ("partial read %d", c));
9684615Snyan	for (b = buf, count = c; count > 0; count -= sizeof(long), b++) {
9784615Snyan		if (ivy_rng_store(b) == 0)
9884615Snyan			break;
9984615Snyan	}
10084615Snyan	return (c - count);
10184615Snyan}
10284615Snyan
10384615Snyanstatic int
10484615Snyanrdrand_modevent(module_t mod, int type, void *unused)
10584615Snyan{
10684615Snyan	int error = 0;
10784615Snyan
10884615Snyan	switch (type) {
10984615Snyan	case MOD_LOAD:
11084615Snyan		if (cpu_feature2 & CPUID2_RDRAND)
11184615Snyan			live_entropy_source_register(&random_ivy);
11284615Snyan		else
11384615Snyan#ifndef KLD_MODULE
11484615Snyan			if (bootverbose)
11584615Snyan#endif
11684615Snyan				printf("%s: RDRAND is not present\n",
11784615Snyan				    random_ivy.ident);
11884615Snyan		break;
11984615Snyan
12084615Snyan	case MOD_UNLOAD:
12184615Snyan		if (cpu_feature2 & CPUID2_RDRAND)
12284615Snyan			live_entropy_source_deregister(&random_ivy);
12384615Snyan		break;
12484615Snyan
12584615Snyan	case MOD_SHUTDOWN:
12684615Snyan		break;
12784615Snyan
12884615Snyan	default:
12984615Snyan		error = EOPNOTSUPP;
13084615Snyan		break;
13184615Snyan
13284615Snyan	}
13384615Snyan
13484615Snyan	return (error);
13584615Snyan}
13684615Snyan
13784615SnyanLIVE_ENTROPY_SRC_MODULE(random_rdrand, rdrand_modevent, 1);
13884615Snyan