1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/*-
* 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. */
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);
}
|
