freebsd-dev/sys/dev/random/nehemiah.c
Konstantin Belousov 97b9c34fc2 Fix rdrand_rng.ko and padlock_rng.ko dependencies, making modules
loadable when not compiled into the kernel.

Approved by:	so (delphij)
Sponsored by:	The FreeBSD Foundation
2016-04-16 06:10:47 +00:00

155 lines
3.8 KiB
C

/*-
* Copyright (c) 2013-2015 Mark R V Murray
* Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
* 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/conf.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/random.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>
static void random_nehemiah_init(void);
static void random_nehemiah_deinit(void);
static u_int random_nehemiah_read(void *, u_int);
static struct random_source random_nehemiah = {
.rs_ident = "VIA Nehemiah Padlock RNG",
.rs_source = RANDOM_PURE_NEHEMIAH,
.rs_read = random_nehemiah_read
};
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"
"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);
}
/* It is specifically allowed that buf is a multiple of sizeof(long) */
static u_int
random_nehemiah_read(void *buf, u_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) {
random_source_register(&random_nehemiah);
printf("random: fast provider: \"%s\"\n", random_nehemiah.rs_ident);
random_nehemiah_init();
}
break;
case MOD_UNLOAD:
if (via_feature_rng & VIA_HAS_RNG) {
random_nehemiah_deinit();
random_source_deregister(&random_nehemiah);
}
break;
case MOD_SHUTDOWN:
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
DEV_MODULE(nehemiah, nehemiah_modevent, NULL);
MODULE_VERSION(nehemiah, 1);
MODULE_DEPEND(nehemiah, random_device, 1, 1, 1);