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/*-
* Copyright (c) 2013 Mark R V Murray
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/random.h>
#include <sys/selinfo.h>
#include <sys/systm.h>
#include <machine/segments.h>
#include <machine/pcb.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>
#include <dev/random/randomdev.h>
#include <dev/random/randomdev_soft.h>
#include <dev/random/random_harvestq.h>
#include <dev/random/live_entropy_sources.h>
#include <dev/random/random_adaptors.h>
static void random_nehemiah_init(void);
static void random_nehemiah_deinit(void);
static int random_nehemiah_read(void *, int);
static struct random_hardware_source random_nehemiah = {
.ident = "Hardware, VIA Nehemiah Padlock RNG",
.source = RANDOM_PURE_NEHEMIAH,
.read = random_nehemiah_read
};
/* TODO: now that the Davies-Meyer hash is gone and we only use
* the 'xstore' instruction, do we still need to preserve the
* FPU state with fpu_kern_(enter|leave)() ?
*/
static struct fpu_kern_ctx *fpu_ctx_save;
/* This H/W source never stores more than 8 bytes in one go */
/* ARGSUSED */
static __inline size_t
VIA_RNG_store(void *buf)
{
uint32_t retval = 0;
uint32_t rate = 0;
#ifdef __GNUCLIKE_ASM
__asm __volatile(
"movl $0,%%edx\n\t"
".byte 0x0f, 0xa7, 0xc0" /* xstore */
: "=a" (retval), "+d" (rate), "+D" (buf)
:
: "memory"
);
#endif
if (rate == 0)
return (retval&0x1f);
return (0);
}
static void
random_nehemiah_init(void)
{
fpu_ctx_save = fpu_kern_alloc_ctx(FPU_KERN_NORMAL);
}
static void
random_nehemiah_deinit(void)
{
fpu_kern_free_ctx(fpu_ctx_save);
}
static int
random_nehemiah_read(void *buf, int c)
{
uint8_t *b;
size_t count, ret;
uint64_t tmp;
if ((fpu_kern_enter(curthread, fpu_ctx_save, FPU_KERN_NORMAL) == 0)) {
b = buf;
for (count = c; count > 0; count -= ret) {
ret = MIN(VIA_RNG_store(&tmp), count);
memcpy(b, &tmp, ret);
b += ret;
}
fpu_kern_leave(curthread, fpu_ctx_save);
}
else
c = 0;
return (c);
}
static int
nehemiah_modevent(module_t mod, int type, void *unused)
{
int error = 0;
switch (type) {
case MOD_LOAD:
if (via_feature_rng & VIA_HAS_RNG) {
live_entropy_source_register(&random_nehemiah);
random_nehemiah_init();
} else
#ifndef KLD_MODULE
if (bootverbose)
#endif
printf("%s: VIA Padlock RNG not present\n",
random_nehemiah.ident);
break;
case MOD_UNLOAD:
if (via_feature_rng & VIA_HAS_RNG)
random_nehemiah_deinit();
live_entropy_source_deregister(&random_nehemiah);
break;
case MOD_SHUTDOWN:
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
LIVE_ENTROPY_SRC_MODULE(nehemiah, nehemiah_modevent, 1);
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