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sys/kern/subr_prng.c
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/*- | |||||
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD | |||||
* | |||||
* Copyright 2020 Conrad Meyer <cem@FreeBSD.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. | |||||
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/pcpu.h> | |||||
#include <sys/prng.h> | |||||
#include <sys/smp.h> | |||||
#include <sys/systm.h> | |||||
#if !PCG_HAS_128BIT_OPS | |||||
/* On 32-bit platforms, gang together two 32-bit generators. */ | |||||
rpokala: You're checking for 128bit support, but implementing 64-bit support...? | |||||
Done Inline ActionsThe 64-bit generators use a 128-bit integer state. cem: The 64-bit generators use a 128-bit integer state. | |||||
typedef struct { | |||||
pcg32u_random_t states[2]; | |||||
} pcg64u_random_t; | |||||
static inline void | |||||
pcg64u_srandom_r(pcg64u_random_t *state64, uint64_t seed) | |||||
{ | |||||
pcg32u_srandom_r(&state64->states[0], seed); | |||||
pcg32u_srandom_r(&state64->states[1], seed); | |||||
} | |||||
static inline uint64_t | |||||
pcg64u_random_r(pcg64u_random_t *state64) | |||||
{ | |||||
return ((((uint64_t)pcg32u_random_r(&state64->states[0])) << 32) | | |||||
pcg32u_random_r(&state64->states[1])); | |||||
} | |||||
static inline uint64_t | |||||
pcg64u_boundedrand_r(pcg64u_random_t *state64, uint64_t bound) | |||||
{ | |||||
uint64_t threshold = -bound % bound; | |||||
for (;;) { | |||||
uint64_t r = pcg64u_random_r(state64); | |||||
if (r >= threshold) | |||||
return (r % bound); | |||||
} | |||||
} | |||||
#endif | |||||
DPCPU_DEFINE_STATIC(pcg32u_random_t, pcpu_prng32_state); | |||||
DPCPU_DEFINE_STATIC(pcg64u_random_t, pcpu_prng64_state); | |||||
static void | |||||
prng_init(void *dummy __unused) | |||||
{ | |||||
pcg32u_random_t *state; | |||||
pcg64u_random_t *state64; | |||||
int i; | |||||
CPU_FOREACH(i) { | |||||
state = DPCPU_ID_PTR(i, pcpu_prng32_state); | |||||
pcg32u_srandom_r(state, 1); | |||||
state64 = DPCPU_ID_PTR(i, pcpu_prng64_state); | |||||
pcg64u_srandom_r(state64, 1); | |||||
} | |||||
} | |||||
SYSINIT(prng_init, SI_SUB_CPU, SI_ORDER_ANY, prng_init, NULL); | |||||
uint32_t | |||||
prng32(void) | |||||
{ | |||||
uint32_t r; | |||||
critical_enter(); | |||||
r = pcg32u_random_r(DPCPU_PTR(pcpu_prng32_state)); | |||||
critical_exit(); | |||||
return (r); | |||||
} | |||||
uint32_t | |||||
prng32_bounded(uint32_t bound) | |||||
{ | |||||
uint32_t r; | |||||
critical_enter(); | |||||
r = pcg32u_boundedrand_r(DPCPU_PTR(pcpu_prng32_state), bound); | |||||
critical_exit(); | |||||
return (r); | |||||
} | |||||
uint64_t | |||||
prng64(void) | |||||
{ | |||||
uint64_t r; | |||||
critical_enter(); | |||||
r = pcg64u_random_r(DPCPU_PTR(pcpu_prng64_state)); | |||||
critical_exit(); | |||||
return (r); | |||||
} | |||||
uint64_t | |||||
prng64_bounded(uint64_t bound) | |||||
{ | |||||
uint64_t r; | |||||
critical_enter(); | |||||
r = pcg64u_boundedrand_r(DPCPU_PTR(pcpu_prng64_state), bound); | |||||
critical_exit(); | |||||
return (r); | |||||
} |
You're checking for 128bit support, but implementing 64-bit support...?