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hyperentropy.c revision 1.7.2.3 
      1 /*	$NetBSD: hyperentropy.c,v 1.7.2.3 2017/12/03 11:39:16 jdolecek Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2014 Antti Kantee.  All Rights Reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     16  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     25  * SUCH DAMAGE.
     26  */
     27 
     28 #include <sys/cdefs.h>
     29 __KERNEL_RCSID(0, "$NetBSD: hyperentropy.c,v 1.7.2.3 2017/12/03 11:39:16 jdolecek Exp $");
     30 
     31 #include <sys/param.h>
     32 #include <sys/kmem.h>
     33 #include <sys/mutex.h>
     34 #include <sys/rndpool.h>
     35 #include <sys/rndsource.h>
     36 
     37 #include <rump-sys/kern.h>
     38 
     39 #include <rump/rumpuser.h>
     40 
     41 static kmutex_t rndsrc_lock;
     42 static krndsource_t rndsrc;
     43 
     44 #define MAXGET (RND_POOLBITS/NBBY)
     45 static void
     46 feedrandom(size_t bytes, void *cookie __unused)
     47 {
     48 	uint8_t *rnddata;
     49 	size_t n, nread;
     50 
     51 	rnddata = kmem_intr_alloc(MAXGET, KM_SLEEP);
     52 	n = 0;
     53 	while (n < MIN(MAXGET, bytes)) {
     54 		if (rumpuser_getrandom(rnddata + n, MIN(MAXGET, bytes) - n,
     55 			RUMPUSER_RANDOM_HARD|RUMPUSER_RANDOM_NOWAIT, &nread)
     56 		    != 0)
     57 			break;
     58 		n += MIN(nread, MIN(MAXGET, bytes) - n);
     59 	}
     60 	if (n) {
     61 		mutex_enter(&rndsrc_lock);
     62 		rnd_add_data_sync(&rndsrc, rnddata, n, NBBY*n);
     63 		mutex_exit(&rndsrc_lock);
     64 	}
     65 	kmem_intr_free(rnddata, MAXGET);
     66 }
     67 
     68 void
     69 rump_hyperentropy_init(void)
     70 {
     71 
     72 	mutex_init(&rndsrc_lock, MUTEX_DEFAULT, IPL_VM);
     73 
     74 	rndsource_setcb(&rndsrc, &feedrandom, NULL);
     75 	rnd_attach_source(&rndsrc, "rump_hyperent", RND_TYPE_VM,
     76 	    RND_FLAG_COLLECT_VALUE|RND_FLAG_HASCB);
     77 	feedrandom(MAXGET, NULL);
     78 }
     79