7c3547bacd
harvester, which now always calls hwrngs with the buffer length multiple of the word size. This allows to remove the excessive memory accesses to temporary buffer when saving the entropy word. Streamline the assembly and unify it between i386 and amd64. Reviewed by: markm, des Approved by: so (des) Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
138 lines
3.7 KiB
C
138 lines
3.7 KiB
C
/*-
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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/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/selinfo.h>
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#include <sys/systm.h>
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#include <machine/md_var.h>
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#include <machine/specialreg.h>
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#include <dev/random/randomdev.h>
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#include <dev/random/randomdev_soft.h>
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#include <dev/random/random_harvestq.h>
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#include <dev/random/live_entropy_sources.h>
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#include <dev/random/random_adaptors.h>
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#define RETRY_COUNT 10
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static int random_ivy_read(void *, int);
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static struct random_hardware_source random_ivy = {
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.ident = "Hardware, Intel IvyBridge+ RNG",
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.source = RANDOM_PURE_RDRAND,
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.read = random_ivy_read
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};
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static inline int
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ivy_rng_store(long *buf)
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{
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#ifdef __GNUCLIKE_ASM
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long tmp;
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int retry;
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retry = RETRY_COUNT;
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__asm __volatile(
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"1:\n\t"
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"rdrand %2\n\t" /* read randomness into tmp */
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"jb 2f\n\t" /* CF is set on success, exit retry loop */
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"dec %0\n\t" /* otherwise, retry-- */
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"jne 1b\n\t" /* and loop if retries are not exhausted */
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"jmp 3f\n" /* failure, retry is 0, used as return value */
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"2:\n\t"
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"mov %2,%1\n\t" /* *buf = tmp */
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"3:"
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: "+q" (retry), "=m" (*buf), "=q" (tmp) : : "cc");
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return (retry);
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#else /* __GNUCLIKE_ASM */
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return (0);
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#endif
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}
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static int
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random_ivy_read(void *buf, int c)
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{
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long *b;
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int count;
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KASSERT(c % sizeof(long) == 0, ("partial read %d", c));
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for (b = buf, count = c; count > 0; count -= sizeof(long), b++) {
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if (ivy_rng_store(b) == 0)
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break;
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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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rdrand_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_feature2 & CPUID2_RDRAND)
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live_entropy_source_register(&random_ivy);
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else
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#ifndef KLD_MODULE
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if (bootverbose)
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#endif
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printf("%s: RDRAND is not present\n",
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random_ivy.ident);
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break;
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case MOD_UNLOAD:
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if (cpu_feature2 & CPUID2_RDRAND)
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live_entropy_source_deregister(&random_ivy);
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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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LIVE_ENTROPY_SRC_MODULE(random_rdrand, rdrand_modevent, 1);
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