7384206a94
Move fast entropy source registration to the earlier SI_SUB_RANDOM:SI_ORDER_FOURTH and move random_harvestq_prime after that. Relocate the registration routines out of the much later randomdev module and into random_harvestq. This is necessary for the fast random sources to actually register before we perform random_harvestq_prime() early in the kernel boot. No functional change. Reviewed by: delphij, markjm Approved by: secteam(delphij) Differential Revision: https://reviews.freebsd.org/D21308
149 lines
4.0 KiB
C
149 lines
4.0 KiB
C
/*-
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* Copyright (c) 2018 Justin Hibbits
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* Copyright (c) 2013 The FreeBSD Foundation
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* Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
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* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
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* All rights reserved.
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*
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* Portions of this software were developed by Konstantin Belousov
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* under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/conf.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/random.h>
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#include <sys/systm.h>
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#include <machine/cpu.h>
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#include <machine/md_var.h>
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#include <dev/random/randomdev.h>
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/*
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* Power ISA 3.0 adds a "darn" instruction (Deliver A Random Number). The RNG
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* backing this instruction conforms to NIST SP800-90B and SP800-90C at the
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* point of hardware design, and provides a minimum of 0.5 bits of entropy per
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* bit.
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*/
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#define RETRY_COUNT 10
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static u_int random_darn_read(void *, u_int);
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static struct random_source random_darn = {
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.rs_ident = "PowerISA DARN random number generator",
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.rs_source = RANDOM_PURE_DARN,
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.rs_read = random_darn_read
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};
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static inline int
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darn_rng_store(u_long *buf)
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{
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u_long rndval;
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int retry;
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for (retry = RETRY_COUNT; retry > 0; --retry) {
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/* "DARN %rN, 1" instruction */
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/*
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* Arguments for DARN: rN and "L", where "L" can be one of:
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* 0 - 32-bit conditional random number
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* 1 - Conditional random number (conditioned to remove bias)
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* 2 - Raw random number (unprocessed, may include bias)
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* 3 - Reserved
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*/
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__asm __volatile(".long 0x7c0105e6 | (%0 << 21)" :
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"+r"(rndval));
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if (rndval != ~0)
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break;
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}
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*buf = rndval;
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return (retry);
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}
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/* It is required that buf length is a multiple of sizeof(u_long). */
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static u_int
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random_darn_read(void *buf, u_int c)
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{
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u_long *b, rndval;
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u_int count;
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KASSERT(c % sizeof(*b) == 0, ("partial read %d", c));
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b = buf;
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for (count = c; count > 0; count -= sizeof(*b)) {
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if (darn_rng_store(&rndval) == 0)
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break;
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*b++ = rndval;
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}
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return (c - count);
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}
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static int
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darn_modevent(module_t mod, int type, void *unused)
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{
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int error = 0;
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switch (type) {
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case MOD_LOAD:
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if (cpu_features2 & PPC_FEATURE2_DARN) {
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random_source_register(&random_darn);
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printf("random: fast provider: \"%s\"\n", random_darn.rs_ident);
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}
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break;
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case MOD_UNLOAD:
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if (cpu_features2 & PPC_FEATURE2_DARN)
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random_source_deregister(&random_darn);
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break;
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case MOD_SHUTDOWN:
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break;
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default:
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error = EOPNOTSUPP;
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break;
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}
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return (error);
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}
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static moduledata_t darn_mod = {
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"darn",
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darn_modevent,
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0
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};
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DECLARE_MODULE(darn, darn_mod, SI_SUB_RANDOM, SI_ORDER_FOURTH);
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MODULE_VERSION(darn, 1);
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MODULE_DEPEND(darn, random_harvestq, 1, 1, 1);
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