155 lines
3.8 KiB
C
155 lines
3.8 KiB
C
/*-
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* Copyright (c) 2013-2015 Mark R V Murray
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* Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
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* All rights reserved.
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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/segments.h>
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#include <machine/pcb.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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static void random_nehemiah_init(void);
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static void random_nehemiah_deinit(void);
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static u_int random_nehemiah_read(void *, u_int);
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static struct random_source random_nehemiah = {
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.rs_ident = "VIA Nehemiah Padlock RNG",
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.rs_source = RANDOM_PURE_NEHEMIAH,
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.rs_read = random_nehemiah_read
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};
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static struct fpu_kern_ctx *fpu_ctx_save;
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/* This H/W source never stores more than 8 bytes in one go */
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/* ARGSUSED */
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static __inline size_t
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VIA_RNG_store(void *buf)
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{
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uint32_t retval = 0;
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uint32_t rate = 0;
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#ifdef __GNUCLIKE_ASM
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__asm __volatile(
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"movl $0,%%edx\n\t"
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"xstore"
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: "=a" (retval), "+d" (rate), "+D" (buf)
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:
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: "memory"
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);
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#endif
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if (rate == 0)
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return (retval&0x1f);
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return (0);
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}
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static void
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random_nehemiah_init(void)
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{
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fpu_ctx_save = fpu_kern_alloc_ctx(FPU_KERN_NORMAL);
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}
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static void
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random_nehemiah_deinit(void)
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{
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fpu_kern_free_ctx(fpu_ctx_save);
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}
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/* It is specifically allowed that buf is a multiple of sizeof(long) */
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static u_int
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random_nehemiah_read(void *buf, u_int c)
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{
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uint8_t *b;
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size_t count, ret;
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uint64_t tmp;
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if ((fpu_kern_enter(curthread, fpu_ctx_save, FPU_KERN_NORMAL) == 0)) {
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b = buf;
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for (count = c; count > 0; count -= ret) {
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ret = MIN(VIA_RNG_store(&tmp), count);
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memcpy(b, &tmp, ret);
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b += ret;
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}
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fpu_kern_leave(curthread, fpu_ctx_save);
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}
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else
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c = 0;
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return (c);
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}
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static int
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nehemiah_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 (via_feature_rng & VIA_HAS_RNG) {
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random_source_register(&random_nehemiah);
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printf("random: fast provider: \"%s\"\n", random_nehemiah.rs_ident);
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random_nehemiah_init();
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}
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break;
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case MOD_UNLOAD:
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if (via_feature_rng & VIA_HAS_RNG) {
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random_nehemiah_deinit();
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random_source_deregister(&random_nehemiah);
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}
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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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DEV_MODULE(nehemiah, nehemiah_modevent, NULL);
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MODULE_VERSION(nehemiah, 1);
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MODULE_DEPEND(nehemiah, randomdev, 1, 1, 1);
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