Add support for new Intel on-CPU Bull Mountain random number

generator, found on IvyBridge and supposedly later CPUs, accessible
with RDRAND instruction.

From the Intel whitepapers and articles about Bull Mountain, it seems
that we do not need to perform post-processing of RDRAND results, like
AES-encryption of the data with random IV and keys, which was done for
Padlock. Intel claims that sanitization is performed in hardware.

Make both Padlock and Bull Mountain random generators support code
covered by kernel config options, for the benefit of people who prefer
minimal kernels. Also add the tunables to disable hardware generator
even if detected.

Reviewed by:	markm, secteam (simon)
Tested by:	bapt, Michael Moll <kvedulv@kvedulv.de>
MFC after:	3 weeks

4 files changed, 156 insertions, 32 deletions

diff --git a/sys/dev/random/ivy.c b/sys/dev/random/ivy.c
new file mode 100644
index 0000000..3f9de2d
--- /dev/null
+++ b/sys/dev/random/ivy.c
@@ -0,0 +1,117 @@
+/*-
+ * 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 "opt_cpu.h"
+
+#ifdef IVY_RNG
+
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/selinfo.h>
+#include <sys/systm.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_systat 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$4,%%eax\n"
+#endif
+	    "1:\n"	/* %eax is cleared by processor on failure */
+	    : "=a" (count), "=g" (*tmp) : "a" (0) : "cc");
+	return (count);
+#else /* __GNUCLIKE_ASM */
+	return (0);
+#endif
+}
+
+static void
+random_ivy_init(void)
+{
+}
+
+void
+random_ivy_deinit(void)
+{
+}
+
+static int
+random_ivy_read(void *buf, int c)
+{
+	char *b;
+	long tmp;
+	int count, res, retry;
+
+	for (count = c, b = buf; count > 0; count -= res, b += res) {
+		for (retry = 0; retry < RETRY_COUNT; retry++) {
+			res = ivy_rng_store(&tmp);
+			if (res != 0)
+				break;
+		}
+		if (res == 0)
+			break;
+		if (res > count)
+			res = count;
+		memcpy(b, &tmp, res);
+	}
+	return (c - count);
+}
+
+#endif
diff --git a/sys/dev/random/nehemiah.c b/sys/dev/random/nehemiah.c
index b9f52e7..f3afa89 100644
--- a/sys/dev/random/nehemiah.c
+++ b/sys/dev/random/nehemiah.c
@@ -28,6 +28,10 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "opt_cpu.h"
+
+#ifdef PADLOCK_RNG
+
 #include <sys/param.h>
 #include <sys/time.h>
 #include <sys/lock.h>
@@ -203,3 +207,5 @@ random_nehemiah_read(void *buf, int c)
 	mtx_unlock(&random_nehemiah_mtx);
 	return (c);
 }
+
+#endif
diff --git a/sys/dev/random/nehemiah.h b/sys/dev/random/nehemiah.h
deleted file mode 100644
index b35fb3f..0000000
--- a/sys/dev/random/nehemiah.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/*-
- * Copyright (c) 2000-2004 Mark R V Murray
- * 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.
- *
- * $FreeBSD$
- */
-
-extern struct random_systat random_nehemiah;
diff --git a/sys/dev/random/probe.c b/sys/dev/random/probe.c
index 0bbfd95..3edfe09 100644
--- a/sys/dev/random/probe.c
+++ b/sys/dev/random/probe.c
@@ -28,12 +28,17 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
+#include "opt_cpu.h"
+#endif
+
 #include <sys/types.h>
 #include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/random.h>
 #include <sys/selinfo.h>
-#include <sys/stdint.h>
 #include <sys/sysctl.h>
 
 #if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
@@ -45,7 +50,15 @@ __FBSDID("$FreeBSD$");
 
 #include <dev/random/randomdev.h>
 #include <dev/random/randomdev_soft.h>
-#include <dev/random/nehemiah.h>
+
+#if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
+#ifdef PADLOCK_RNG
+extern struct random_systat random_nehemiah;
+#endif
+#ifdef IVY_RNG
+extern struct random_systat random_ivy;
+#endif
+#endif
 
 void
 random_ident_hardware(struct random_systat *systat)
@@ -56,8 +69,25 @@ random_ident_hardware(struct random_systat *systat)
 
 	/* Then go looking for hardware */
 #if defined(__amd64__) || (defined(__i386__) && !defined(PC98))
+#ifdef PADLOCK_RNG
 	if (via_feature_rng & VIA_HAS_RNG) {
-		*systat = random_nehemiah;
+		int enable;
+
+		enable = 1;
+		TUNABLE_INT_FETCH("hw.nehemiah_rng_enable", &enable);
+		if (enable)
+			*systat = random_nehemiah;
+	}
+#endif
+#ifdef IVY_RNG
+	if (cpu_feature2 & CPUID2_RDRAND) {
+		int enable;
+
+		enable = 1;
+		TUNABLE_INT_FETCH("hw.ivy_rng_enable", &enable);
+		if (enable)
+			*systat = random_ivy;
 	}
 #endif
+#endif
 }