Hi. This is my first post to FreeBSD-Hackers. It's probably the wrong
place at the wrong time and totaly inappropriate in general, so start
flaming right now.
Anyway, I've writting a small patch to enable the thermal noise random
number generator found in the i82802 (i82810).
It breaks the /dev/random semantics slightly as the bitpool never run
out of fresh bits.
Hopefully somebody finds it usefull :-). I do.
BTW, the patch is against the REL-3.3 kernel and x86-only.
/Bjorn
diff -Nru sys.orig/i386/conf/files.i386 sys/i386/conf/files.i386
--- sys.orig/i386/conf/files.i386 Mon Sep 6 00:35:34 1999
+++ sys/i386/conf/files.i386 Fri Jan 7 00:21:44 2000
@@ -79,6 +79,7 @@
i386/i386/globals.s standard
i386/i386/i386-gdbstub.c optional ddb
i386/i386/i686_mem.c standard
+i386/i386/i82802_rng.c standard
i386/i386/identcpu.c standard
i386/i386/in_cksum.c optional inet
i386/i386/initcpu.c standard
diff -Nru sys.orig/i386/i386/i82802_rng.c sys/i386/i386/i82802_rng.c
--- sys.orig/i386/i386/i82802_rng.c Thu Jan 1 00:00:00 1970
+++ sys/i386/i386/i82802_rng.c Fri Jan 7 09:38:43 2000
@@ -0,0 +1,68 @@
+/* $Id$
+ *
+ * Copyright (c) 2000 Bjorn Ahlqvist.
+ * All rights reserved.
+ *
+ * v1.0 - Initial version.
+ *
+ * TODO: We should make sure we're really receiving something
+ * that look random. The specification suggests FIPS 140-1.
+ *
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/kernel.h>
+#include <sys/proc.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+#include <vm/vm_extern.h>
+
+#include <machine/clock.h>
+#include <machine/random.h>
+
+#define I82802_RNG_NAME "i82802 thermal noise random number generator"
+
+#define I82802_HW_RNG_ENABLE 1 /* hw_status */
+#define I82802_HW_RNG_PRESENT 0x40 /* hw_status */
+#define I82802_RNG_DATA_PRESENT 1 /* rng_status */
+#define I82802_RNG_BASE 0xffbc0000 /* absolute address */
+#define I82802_RNG_DELAY 5 /* about 4.5 ms */
+
+struct i82802_rng {
+ u_char fill[0x015f];
+ u_char hw_status;
+ u_char rng_status;
+ u_char rng_data;
+};
+
+
+static struct i82802_rng *rngp;
+int rng_present;
+
+u_char rng_read(void)
+{
+ while(!(rngp->rng_status&I82802_RNG_DATA_PRESENT)) { /* wait.. */
+ if(!curproc) DELAY(I82802_RNG_DELAY); /* ..for data */
+ else tsleep(&rng_read,PRIBIO,"rngrd",1);
+ }
+
+ return(rngp->rng_data); /* got some */
+}
+
+static void rng_probe(void *dummy)
+{
+ rngp=pmap_mapdev(I82802_RNG_BASE,sizeof(*rngp)); /* wire mem */
+
+ rng_present=rngp->hw_status&I82802_HW_RNG_PRESENT; /* present? */
+ if(!rng_present) return; /* no return */
+ rngp->hw_status|=I82802_HW_RNG_ENABLE; /* yes enable */
+
+ printf(I82802_RNG_NAME" at 0x%08x enabled.\n",I82802_RNG_BASE);
+}
+
+SYSINIT(rng,SI_SUB_DRIVERS,SI_ORDER_ANY,rng_probe,NULL)
+
diff -Nru sys.orig/i386/include/random.h sys/i386/include/random.h
--- sys.orig/i386/include/random.h Sun Aug 29 16:06:47 1999
+++ sys/i386/include/random.h Fri Jan 7 02:34:17 2000
@@ -66,8 +66,13 @@
int sc_intr;
};
+/* Exported variables */
+
+extern int rng_present;
+
/* Exported functions */
+u_char rng_read(void);
void rand_initialize(void);
void add_keyboard_randomness(u_char scancode);
inthand2_t add_interrupt_randomness;
diff -Nru sys.orig/i386/isa/random_machdep.c sys/i386/isa/random_machdep.c
--- sys.orig/i386/isa/random_machdep.c Sun Aug 29 16:07:31 1999
+++ sys/i386/isa/random_machdep.c Fri Jan 7 09:36:37 2000
@@ -325,6 +325,13 @@
u_int
read_random(void *buf, u_int nbytes)
{
+ int i;
+
+ if (rng_present) { /* Hardware RNG */
+ for(i=0;i<nbytes;i++) *((u_char *)buf)++=rng_read();
+ return nbytes;
+ }
+
if ((nbytes * 8) > random_state.entropy_count)
nbytes = random_state.entropy_count / 8;
