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      1 /*	$NetBSD: hyperentropy.c,v 1.17 2020/04/30 03:41:20 riastradh 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 1.17 2020/04/30 03:41:20 riastradh Exp $");
     30 
     31 #include <sys/param.h>
     32 #include <sys/kmem.h>
     33 #include <sys/rndsource.h>
     34 
     35 #include <rump-sys/kern.h>
     36 
     37 #include <rump/rumpuser.h>
     38 
     39 static krndsource_t rndsrc;
     40 
     41 static void
     42 feedrandom(size_t bytes, void *cookie __unused)
     43 {
     44 	uint8_t *rnddata;
     45 	size_t n, nread;
     46 
     47 	rnddata = kmem_intr_alloc(bytes, KM_SLEEP);
     48 	n = 0;
     49 	while (n < bytes) {
     50 		if (rumpuser_getrandom(rnddata + n, bytes - n,
     51 			RUMPUSER_RANDOM_HARD|RUMPUSER_RANDOM_NOWAIT, &nread)
     52 		    != 0)
     53 			break;
     54 		n += MIN(nread, bytes - n);
     55 	}
     56 	if (n) {
     57 		rnd_add_data_sync(&rndsrc, rnddata, n, NBBY*n);
     58 	}
     59 	kmem_intr_free(rnddata, bytes);
     60 }
     61 
     62 void
     63 rump_hyperentropy_init(void)
     64 {
     65 
     66 	rndsource_setcb(&rndsrc, &feedrandom, NULL);
     67 	rnd_attach_source(&rndsrc, "rump_hyperent", RND_TYPE_VM,
     68 	    RND_FLAG_COLLECT_VALUE|RND_FLAG_HASCB);
     69 }
     70