Make the UMA harvesting go away completely if not wanted. Default to "not wanted".

Provide and document the RANDOM_ENABLE_UMA option.

Change RANDOM_FAST to RANDOM_UMA to clarify the harvesting.

Remove RANDOM_DEBUG option, replace with SDT probes. These will be of
use to folks measuring the harvesting effect when deciding whether to
use RANDOM_ENABLE_UMA.

Requested by:	scottl and others.
Approved by:	so (/dev/random blanket)
Differential Revision:    https://reviews.freebsd.org/D3197

5 files changed, 19 insertions, 29 deletions

diff --git a/sys/dev/random/build.sh b/sys/dev/random/build.sh
index d1351c4..2b4052d 100755
--- a/sys/dev/random/build.sh
+++ b/sys/dev/random/build.sh
@@ -35,7 +35,7 @@
 #              <(sed -e 's/fortuna/wombat/g' \
 #                    -e 's/FORTUNA/WOMBAT/g' fortuna.c) | less
 #
-cc -g -O0 -pthread -DRANDOM_DEBUG \
+cc -g -O0 -pthread \
 	-I../.. -lstdthreads -Wall \
 	unit_test.c \
 	yarrow.c \
@@ -46,7 +46,7 @@ cc -g -O0 -pthread -DRANDOM_DEBUG \
 	../../crypto/sha2/sha256c.c \
 	-lz \
 	-o yunit_test
-cc -g -O0 -pthread -DRANDOM_DEBUG \
+cc -g -O0 -pthread \
 	-I../.. -lstdthreads -Wall \
 	unit_test.c \
 	fortuna.c \
diff --git a/sys/dev/random/fortuna.c b/sys/dev/random/fortuna.c
index 0b03931..4ae006b 100644
--- a/sys/dev/random/fortuna.c
+++ b/sys/dev/random/fortuna.c
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/mutex.h>
 #include <sys/random.h>
+#include <sys/sdt.h>
 #include <sys/sysctl.h>
 #include <sys/systm.h>
 
@@ -94,6 +95,11 @@ CTASSERT(RANDOM_FORTUNA_DEFPOOLSIZE <= RANDOM_FORTUNA_MAXPOOLSIZE);
 CTASSERT(RANDOM_BLOCKSIZE == sizeof(uint128_t));
 CTASSERT(RANDOM_KEYSIZE == 2*RANDOM_BLOCKSIZE);
 
+/* Probes for dtrace(1) */
+SDT_PROVIDER_DECLARE(random);
+SDT_PROVIDER_DEFINE(random);
+SDT_PROBE_DEFINE2(random, fortuna, event_processor, debug, "u_int", "struct fs_pool *");
+
 /*
  * This is the beastie that needs protecting. It contains all of the
  * state that we are excited about. Exactly one is instantiated.
@@ -379,16 +385,7 @@ random_fortuna_pre_read(void)
 			} else
 				break;
 		}
-#ifdef RANDOM_DEBUG
-		{
-			u_int j;
-
-			printf("random: reseedcount [%d]", fortuna_state.fs_reseedcount);
-			for (j = 0; j < RANDOM_FORTUNA_NPOOLS; j++)
-				printf(" %X", fortuna_state.fs_pool[j].fsp_length);
-			printf("\n");
-		}
-#endif
+		SDT_PROBE2(random, fortuna, event_processor, debug, fortuna_state.fs_reseedcount, fortuna_state.fs_pool);
 		/* FS&K */
 		random_fortuna_reseed_internal(s, i < RANDOM_FORTUNA_NPOOLS ? i + 1 : RANDOM_FORTUNA_NPOOLS);
 		/* Clean up and secure */
diff --git a/sys/dev/random/random_harvestq.c b/sys/dev/random/random_harvestq.c
index 255136c..aad6763 100644
--- a/sys/dev/random/random_harvestq.c
+++ b/sys/dev/random/random_harvestq.c
@@ -170,7 +170,7 @@ random_kthread(void)
 		/* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */
 		for (i = 0; i < RANDOM_ACCUM_MAX; i++) {
 			if (harvest_context.hc_entropy_fast_accumulator.buf[i]) {
-				random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), 4, RANDOM_FAST);
+				random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), 4, RANDOM_UMA);
 				harvest_context.hc_entropy_fast_accumulator.buf[i] = 0;
 			}
 		}
@@ -261,7 +261,7 @@ static const char *(random_source_descr[]) = {
 	"INTERRUPT",
 	"SWI",
 	"FS_ATIME",
-	"HIGH_PERFORMANCE", /* ENVIRONMENTAL_END */
+	"UMA", /* ENVIRONMENTAL_END */
 	"PURE_OCTEON",
 	"PURE_SAFE",
 	"PURE_GLXSB",
diff --git a/sys/dev/random/unit_test.c b/sys/dev/random/unit_test.c
index fac4c8d..f682d17 100644
--- a/sys/dev/random/unit_test.c
+++ b/sys/dev/random/unit_test.c
@@ -29,7 +29,7 @@
 /*
  Build this by going:
 
-cc -g -O0 -pthread -DRANDOM_<alg> -DRANDOM_DEBUG -I../.. -lstdthreads -Wall \
+cc -g -O0 -pthread -DRANDOM_<alg> -I../.. -lstdthreads -Wall \
 	unit_test.c \
 	yarrow.c \
 	fortuna.c \
diff --git a/sys/dev/random/yarrow.c b/sys/dev/random/yarrow.c
index 2ef15a4..5cb1bce 100644
--- a/sys/dev/random/yarrow.c
+++ b/sys/dev/random/yarrow.c
@@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/mutex.h>
 #include <sys/random.h>
+#include <sys/sdt.h>
 #include <sys/sysctl.h>
 #include <sys/systm.h>
 
@@ -77,6 +78,11 @@ __FBSDID("$FreeBSD$");
 CTASSERT(RANDOM_BLOCKSIZE == sizeof(uint128_t));
 CTASSERT(RANDOM_KEYSIZE == 2*RANDOM_BLOCKSIZE);
 
+/* Probes for dtrace(1) */
+SDT_PROVIDER_DECLARE(random);
+SDT_PROVIDER_DEFINE(random);
+SDT_PROBE_DEFINE3(random, yarrow, event_processor, debug, "boolean", "u_int", "struct ys_pool *");
+
 /*
  * This is the beastie that needs protecting. It contains all of the
  * state that we are excited about. Exactly one is instantiated.
@@ -261,20 +267,7 @@ random_yarrow_reseed_internal(u_int fastslow)
 	KASSERT(yarrow_state.ys_pool[RANDOM_YARROW_FAST].ysp_thresh > 0, ("random: Yarrow fast threshold = 0"));
 	KASSERT(yarrow_state.ys_pool[RANDOM_YARROW_SLOW].ysp_thresh > 0, ("random: Yarrow slow threshold = 0"));
 	RANDOM_RESEED_ASSERT_LOCK_OWNED();
-#ifdef RANDOM_DEBUG
-	/* WARNING! This is dangerously tedious to do with mutexes held! */
-	printf("random: %s ", __func__);
-	printf("type/pool = %s ", fastslow == RANDOM_YARROW_FAST ? "RANDOM_YARROW_FAST" : "RANDOM_YARROW_SLOW");
-	printf("seeded = %s\n", yarrow_state.ys_seeded ? "true" : "false");
-	printf("random: fast - thresh %d,1 - ", yarrow_state.ys_pool[RANDOM_YARROW_FAST].ysp_thresh);
-	for (i = RANDOM_START; i < ENTROPYSOURCE; i++)
-		printf(" %d", yarrow_state.ys_pool[RANDOM_YARROW_FAST].ysp_source_bits[i]);
-	printf("\n");
-	printf("random: slow - thresh %d,%d - ", yarrow_state.ys_pool[RANDOM_YARROW_SLOW].ysp_thresh, yarrow_state.ys_slowoverthresh);
-	for (i = RANDOM_START; i < ENTROPYSOURCE; i++)
-		printf(" %d", yarrow_state.ys_pool[RANDOM_YARROW_SLOW].ysp_source_bits[i]);
-	printf("\n");
-#endif
+	SDT_PROBE3(random, yarrow, event_processor, debug, yarrow_state.ys_seeded, yarrow_state.ys_slowoverthresh, yarrow_state.ys_pool);
 	/* 1. Hash the accumulated entropy into v[0] */
 	randomdev_hash_init(&context);
 	/* Feed the slow pool hash in if slow */