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