ivy.c

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    1 /*-
    2  * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer
   10  *    in this position and unchanged.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   25  *
   26  */
   27 
   28 #include <sys/cdefs.h>
   29 __FBSDID("$FreeBSD: releng/8.4/sys/dev/random/ivy.c 240994 2012-09-27 10:56:25Z kib $");
   30 
   31 #include "opt_cpu.h"
   32 
   33 #ifdef RDRAND_RNG
   34 
   35 #include <sys/param.h>
   36 #include <sys/time.h>
   37 #include <sys/lock.h>
   38 #include <sys/mutex.h>
   39 #include <sys/selinfo.h>
   40 #include <sys/systm.h>
   41 #include <dev/random/randomdev.h>
   42 
   43 #define RETRY_COUNT     10
   44 
   45 static void random_ivy_init(void);
   46 static void random_ivy_deinit(void);
   47 static int random_ivy_read(void *, int);
   48 
   49 struct random_systat random_ivy = {
   50         .ident = "Hardware, Intel IvyBridge+ RNG",
   51         .init = random_ivy_init,
   52         .deinit = random_ivy_deinit,
   53         .read = random_ivy_read,
   54         .write = (random_write_func_t *)random_null_func,
   55         .reseed = (random_reseed_func_t *)random_null_func,
   56         .seeded = 1,
   57 };
   58 
   59 static inline int
   60 ivy_rng_store(long *tmp)
   61 {
   62 #ifdef __GNUCLIKE_ASM
   63         uint32_t count;
   64 
   65         __asm __volatile(
   66 #ifdef __amd64__
   67             ".byte\t0x48,0x0f,0xc7,0xf0\n\t" /* rdrand %rax */
   68             "jnc\t1f\n\t"
   69             "movq\t%%rax,%1\n\t"
   70             "movl\t$8,%%eax\n"
   71 #else /* i386 */
   72             ".byte\t0x0f,0xc7,0xf0\n\t" /* rdrand %eax */
   73             "jnc\t1f\n\t"
   74             "movl\t%%eax,%1\n\t"
   75             "movl\t$4,%%eax\n"
   76 #endif
   77             "1:\n"      /* %eax is cleared by processor on failure */
   78             : "=a" (count), "=g" (*tmp) : "a" (0) : "cc");
   79         return (count);
   80 #else /* __GNUCLIKE_ASM */
   81         return (0);
   82 #endif
   83 }
   84 
   85 static void
   86 random_ivy_init(void)
   87 {
   88 }
   89 
   90 void
   91 random_ivy_deinit(void)
   92 {
   93 }
   94 
   95 static int
   96 random_ivy_read(void *buf, int c)
   97 {
   98         char *b;
   99         long tmp;
  100         int count, res, retry;
  101 
  102         for (count = c, b = buf; count > 0; count -= res, b += res) {
  103                 for (retry = 0; retry < RETRY_COUNT; retry++) {
  104                         res = ivy_rng_store(&tmp);
  105                         if (res != 0)
  106                                 break;
  107                 }
  108                 if (res == 0)
  109                         break;
  110                 if (res > count)
  111                         res = count;
  112                 memcpy(b, &tmp, res);
  113         }
  114         return (c - count);
  115 }
  116 
  117 #endif

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FreeBSD/Linux Kernel Cross Reference sys/dev/random/ivy.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/random/ivy.c