diff --git a/sys/dev/random/ivy.c b/sys/dev/random/ivy.c
index 7784e8be3fc2..9b4001692ada 100644
--- a/sys/dev/random/ivy.c
+++ b/sys/dev/random/ivy.c
@@ -1,144 +1,137 @@
 /*-
+ * Copyright (c) 2013 The FreeBSD Foundation
  * Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
  * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
  * All rights reserved.
  *
+ * Portions of this software were developed by Konstantin Belousov
+ * under sponsorship from the FreeBSD Foundation.
+ *
  * 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/kernel.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
 #include <sys/module.h>
 #include <sys/random.h>
 #include <sys/selinfo.h>
 #include <sys/systm.h>
 
 #include <machine/md_var.h>
 #include <machine/specialreg.h>
 
 #include <dev/random/randomdev.h>
 #include <dev/random/randomdev_soft.h>
 #include <dev/random/random_harvestq.h>
 #include <dev/random/live_entropy_sources.h>
 #include <dev/random/random_adaptors.h>
 
 #define	RETRY_COUNT	10
 
 static int random_ivy_read(void *, int);
 
 static struct random_hardware_source random_ivy = {
 	.ident = "Hardware, Intel IvyBridge+ RNG",
 	.source = RANDOM_PURE_RDRAND,
 	.read = random_ivy_read
 };
 
 static inline int
-ivy_rng_store(uint64_t *tmp)
+ivy_rng_store(long *buf)
 {
 #ifdef __GNUCLIKE_ASM
-	uint32_t count;
+	long tmp;
+	int retry;
 
+	retry = RETRY_COUNT;
 	__asm __volatile(
-#ifdef __amd64__
-	    "rdrand\t%%rax\n\t"
-	    "jnc\t1f\n\t"
-	    "movq\t%%rax,%1\n\t"
-	    "movl\t$8,%%eax\n"
-#else /* i386 */
-	    "rdrand\t%%eax\n\t"
-	    "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);
+	    "1:\n\t"
+	    "rdrand	%2\n\t"	/* read randomness into tmp */
+	    "jb		2f\n\t" /* CF is set on success, exit retry loop */
+	    "dec	%0\n\t" /* otherwise, retry-- */
+	    "jne	1b\n\t" /* and loop if retries are not exhausted */
+	    "jmp	3f\n"	/* failure, retry is 0, used as return value */
+	    "2:\n\t"
+	    "mov	%2,%1\n\t" /* *buf = tmp */
+	    "3:"
+	    : "+q" (retry), "=m" (*buf), "=q" (tmp) : : "cc");
+	return (retry);
 #else /* __GNUCLIKE_ASM */
 	return (0);
 #endif
 }
 
 static int
 random_ivy_read(void *buf, int c)
 {
-	uint8_t *b;
-	int count, ret, retry;
-	uint64_t tmp;
-
-	b = buf;
-	for (count = c; count > 0; count -= ret) {
-		for (retry = 0; retry < RETRY_COUNT; retry++) {
-			ret = ivy_rng_store(&tmp);
-			if (ret != 0)
-				break;
-		}
-		if (ret == 0)
+	long *b;
+	int count;
+
+	KASSERT(c % sizeof(long) == 0, ("partial read %d", c));
+	for (b = buf, count = c; count > 0; count -= sizeof(long), b++) {
+		if (ivy_rng_store(b) == 0)
 			break;
-		if (ret > count)
-			ret = count;
-		memcpy(b, &tmp, ret);
-		b += ret;
 	}
 	return (c - count);
 }
 
 static int
 rdrand_modevent(module_t mod, int type, void *unused)
 {
 	int error = 0;
 
 	switch (type) {
 	case MOD_LOAD:
 		if (cpu_feature2 & CPUID2_RDRAND)
 			live_entropy_source_register(&random_ivy);
 		else
 #ifndef KLD_MODULE
 			if (bootverbose)
 #endif
 				printf("%s: RDRAND is not present\n",
 				    random_ivy.ident);
 		break;
 
 	case MOD_UNLOAD:
 		if (cpu_feature2 & CPUID2_RDRAND)
 			live_entropy_source_deregister(&random_ivy);
 		break;
 
 	case MOD_SHUTDOWN:
 		break;
 
 	default:
 		error = EOPNOTSUPP;
 		break;
 
 	}
 
 	return (error);
 }
 
 LIVE_ENTROPY_SRC_MODULE(random_rdrand, rdrand_modevent, 1);