MFC: 313176, 313177, 313359

Replace the implementation of DTrace's RAND subroutine for generating
low-quality random numbers with a modern implementation (xoroshiro128+)
that is capable of generating better quality randomness without compromising performance.

Submitted by:	Graeme Jenkinson

4 files changed, 157 insertions, 2 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
index 0d9c1e3..64ba08a 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
@@ -124,6 +124,7 @@
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/ptrace.h>
+#include <sys/random.h>
 #include <sys/rwlock.h>
 #include <sys/sx.h>
 #include <sys/sysctl.h>
@@ -136,6 +137,8 @@
 #include "dtrace_debug.c"
 #endif
 
+#include "dtrace_xoroshiro128_plus.h"
+
 /*
  * DTrace Tunable Variables
  *
@@ -298,7 +301,6 @@ static kmutex_t		dtrace_meta_lock;	/* meta-provider state lock */
 #define vuprintf	vprintf
 #define ttoproc(_a)	((_a)->td_proc)
 #define crgetzoneid(_a)	0
-#define	NCPU		MAXCPU
 #define SNOCD		0
 #define CPU_ON_INTR(_a)	0
 
@@ -4119,7 +4121,8 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
 
 	switch (subr) {
 	case DIF_SUBR_RAND:
-		regs[rd] = (dtrace_gethrtime() * 2416 + 374441) % 1771875;
+		regs[rd] = dtrace_xoroshiro128_plus_next(
+		    state->dts_rstate[curcpu]);
 		break;
 
 #ifdef illumos
@@ -14408,6 +14411,7 @@ dtrace_state_create(struct cdev *dev, struct ucred *cred __unused)
 	dtrace_state_t *state;
 	dtrace_optval_t *opt;
 	int bufsize = NCPU * sizeof (dtrace_buffer_t), i;
+	int cpu_it;
 
 	ASSERT(MUTEX_HELD(&dtrace_lock));
 	ASSERT(MUTEX_HELD(&cpu_lock));
@@ -14463,6 +14467,21 @@ dtrace_state_create(struct cdev *dev, struct ucred *cred __unused)
 	state->dts_buffer = kmem_zalloc(bufsize, KM_SLEEP);
 	state->dts_aggbuffer = kmem_zalloc(bufsize, KM_SLEEP);
 
+	/*
+         * Allocate and initialise the per-process per-CPU random state.
+	 * SI_SUB_RANDOM < SI_SUB_DTRACE_ANON therefore entropy device is
+         * assumed to be seeded at this point (if from Fortuna seed file).
+	 */
+	(void) read_random(&state->dts_rstate[0], 2 * sizeof(uint64_t));
+	for (cpu_it = 1; cpu_it < NCPU; cpu_it++) {
+		/*
+		 * Each CPU is assigned a 2^64 period, non-overlapping
+		 * subsequence.
+		 */
+		dtrace_xoroshiro128_plus_jump(state->dts_rstate[cpu_it-1],
+		    state->dts_rstate[cpu_it]); 
+	}
+
 #ifdef illumos
 	state->dts_cleaner = CYCLIC_NONE;
 	state->dts_deadman = CYCLIC_NONE;
diff --git a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace_xoroshiro128_plus.c b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace_xoroshiro128_plus.c
new file mode 100644
index 0000000..fbc656a
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace_xoroshiro128_plus.c
@@ -0,0 +1,89 @@
+/*-
+ * Copyright (c) 2016 (Graeme Jenkinson)
+ * All rights reserved.
+ *
+ * This software was developed by BAE Systems, the University of Cambridge
+ * Computer Laboratory, and Memorial University under DARPA/AFRL contract
+ * FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent Computing
+ * (TC) research program.
+ *
+ * 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.
+ * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/types.h>
+
+#include "dtrace_xoroshiro128_plus.h"
+
+static __inline uint64_t
+rotl(const uint64_t x, int k)
+{
+	return (x << k) | (x >> (64 - k));
+}
+
+/*
+ * This is the jump function for the generator. It is equivalent to 2^64 calls
+ * to next(); it can be used to generate 2^64 non-overlapping subsequences for
+ * parallel computations.
+ */
+void
+dtrace_xoroshiro128_plus_jump(uint64_t * const state,
+	uint64_t * const jump_state)
+{
+	static const uint64_t JUMP[] = { 0xbeac0467eba5facb,
+		0xd86b048b86aa9922 };
+
+	uint64_t s0 = 0;
+	uint64_t s1 = 0;
+	int i = 0;
+	int b = 0;
+	for (i = 0; i < sizeof JUMP / sizeof *JUMP; i++) {
+		for (b = 0; b < 64; b++) {
+			if (JUMP[i] & 1ULL << b) {
+				s0 ^= state[0];
+				s1 ^= state[1];
+			}
+			dtrace_xoroshiro128_plus_next(state);
+		}
+	}
+	jump_state[0] = s0;
+	jump_state[1] = s1;
+}
+
+/*
+ * xoroshiro128+ - XOR/rotate/shift/rotate
+ * xorshift.di.unimi.it
+ */
+uint64_t
+dtrace_xoroshiro128_plus_next(uint64_t * const state)
+{
+	const uint64_t s0 = state[0];
+	uint64_t s1 = state[1];
+	uint64_t result;
+	result = s0 + s1;
+
+	s1 ^= s0;
+	state[0] = rotl(s0, 55) ^ s1 ^ (s1 << 14);
+	state[1] = rotl(s1, 36);
+
+	return result;
+}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace_xoroshiro128_plus.h b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace_xoroshiro128_plus.h
new file mode 100644
index 0000000..73b1722
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace_xoroshiro128_plus.h
@@ -0,0 +1,41 @@
+/*-
+ * Copyright (c) 2016 (Graeme Jenkinson)
+ * All rights reserved.
+ *
+ * This software was developed by BAE Systems, the University of Cambridge
+ * Computer Laboratory, and Memorial University under DARPA/AFRL contract
+ * FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent Computing
+ * (TC) research program.
+ *
+ * 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.
+ * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
+ *
+ */
+
+#ifndef _DTRACE_XOROSHIRO128_PLUS_H
+#define _DTRACE_XOROSHIRO128_PLUS_H
+
+#include <sys/types.h>
+
+void dtrace_xoroshiro128_plus_jump(uint64_t * const, uint64_t * const);
+uint64_t dtrace_xoroshiro128_plus_next(uint64_t * const);
+
+#endif
diff --git a/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h b/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h
index 1ec9091..1d9d800 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h
@@ -50,6 +50,7 @@ extern "C" {
  */
 
 #include <sys/dtrace.h>
+
 #ifndef illumos
 #ifdef __sparcv9
 typedef uint32_t		pc_t;
@@ -65,6 +66,10 @@ typedef	u_long			greg_t;
 #define	DTRACE_MAXPROPLEN		128
 #define	DTRACE_DYNVAR_CHUNKSIZE		256
 
+#ifdef __FreeBSD__
+#define	NCPU		MAXCPU
+#endif /* __FreeBSD__ */
+
 struct dtrace_probe;
 struct dtrace_ecb;
 struct dtrace_predicate;
@@ -1168,6 +1173,7 @@ struct dtrace_state {
 	dtrace_cred_t dts_cred;			/* credentials */
 	size_t dts_nretained;			/* number of retained enabs */
 	int dts_getf;				/* number of getf() calls */
+	uint64_t dts_rstate[NCPU][2];		/* per-CPU random state */
 };
 
 struct dtrace_provider {