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/*-
* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/selinfo.h>
#include <sys/systm.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>
#include <dev/random/random_adaptors.h>
#include <dev/random/randomdev.h>
#define RETRY_COUNT 10
static void random_ivy_init(void);
static void random_ivy_deinit(void);
static int random_ivy_read(void *, int);
struct random_adaptor random_ivy = {
.ident = "Hardware, Intel IvyBridge+ RNG",
.init = random_ivy_init,
.deinit = random_ivy_deinit,
.read = random_ivy_read,
.write = (random_write_func_t *)random_null_func,
.reseed = (random_reseed_func_t *)random_null_func,
.seeded = 1,
};
static inline int
ivy_rng_store(long *tmp)
{
#ifdef __GNUCLIKE_ASM
uint32_t count;
__asm __volatile(
#ifdef __amd64__
".byte\t0x48,0x0f,0xc7,0xf0\n\t" /* rdrand %rax */
"jnc\t1f\n\t"
"movq\t%%rax,%1\n\t"
"movl\t$8,%%eax\n"
#else /* i386 */
".byte\t0x0f,0xc7,0xf0\n\t" /* rdrand %eax */
"jnc\t1f\n\t"
"movl\t%%eax,%1\n\t"
"movl\t$4,%%eax\n"
#endif
"1:\n" /* %eax is cleared by processor on failure */
: "=a" (count), "=g" (*tmp) : "a" (0) : "cc");
return (count);
#else /* __GNUCLIKE_ASM */
return (0);
#endif
}
static void
random_ivy_init(void)
{
}
void
random_ivy_deinit(void)
{
}
static int
random_ivy_read(void *buf, int c)
{
char *b;
long tmp;
int count, res, retry;
for (count = c, b = buf; count > 0; count -= res, b += res) {
for (retry = 0; retry < RETRY_COUNT; retry++) {
res = ivy_rng_store(&tmp);
if (res != 0)
break;
}
if (res == 0)
break;
if (res > count)
res = count;
memcpy(b, &tmp, res);
}
return (c - count);
}
static int
rdrand_modevent(module_t mod, int type, void *unused)
{
switch (type) {
case MOD_LOAD:
if (cpu_feature2 & CPUID2_RDRAND) {
random_adaptor_register("rdrand", &random_ivy);
EVENTHANDLER_INVOKE(random_adaptor_attach, &random_ivy);
return (0);
} else {
#ifndef KLD_MODULE
if (bootverbose)
#endif
printf(
"%s: RDRAND feature is not present on this CPU\n",
random_ivy.ident);
#ifdef KLD_MODULE
return (ENXIO);
#else
return (0);
#endif
}
}
return (EINVAL);
}
RANDOM_ADAPTOR_MODULE(random_rdrand, rdrand_modevent, 1);
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