1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2012 Gleb Smirnoff <glebius@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/param.h>
30#include <sys/systm.h>
31#include <sys/kernel.h>
32#include <sys/lock.h>
33#include <sys/mutex.h>
34#include <sys/proc.h>
35#include <sys/sched.h>
36#include <sys/smp.h>
37#include <sys/sysctl.h>
38#include <vm/uma.h>
39
40#define IN_SUBR_COUNTER_C
41#include <sys/counter.h>
42
43void
44counter_u64_zero(counter_u64_t c)
45{
46
47	counter_u64_zero_inline(c);
48}
49
50uint64_t
51counter_u64_fetch(counter_u64_t c)
52{
53
54	return (counter_u64_fetch_inline(c));
55}
56
57counter_u64_t
58counter_u64_alloc(int flags)
59{
60
61	return (uma_zalloc_pcpu(pcpu_zone_8, flags | M_ZERO));
62}
63
64void
65counter_u64_free(counter_u64_t c)
66{
67
68	uma_zfree_pcpu(pcpu_zone_8, c);
69}
70
71int
72sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS)
73{
74	uint64_t out;
75	int error;
76
77	out = counter_u64_fetch(*(counter_u64_t *)arg1);
78
79	error = SYSCTL_OUT(req, &out, sizeof(uint64_t));
80
81	if (error || !req->newptr)
82		return (error);
83
84	/*
85	 * Any write attempt to a counter zeroes it.
86	 */
87	counter_u64_zero(*(counter_u64_t *)arg1);
88
89	return (0);
90}
91
92int
93sysctl_handle_counter_u64_array(SYSCTL_HANDLER_ARGS)
94{
95	uint64_t *out;
96	int error;
97
98	out = malloc(arg2 * sizeof(uint64_t), M_TEMP, M_WAITOK);
99	for (int i = 0; i < arg2; i++)
100		out[i] = counter_u64_fetch(((counter_u64_t *)arg1)[i]);
101
102	error = SYSCTL_OUT(req, out, arg2 * sizeof(uint64_t));
103	free(out, M_TEMP);
104
105	if (error || !req->newptr)
106		return (error);
107
108	/*
109	 * Any write attempt to a counter zeroes it.
110	 */
111	for (int i = 0; i < arg2; i++)
112		counter_u64_zero(((counter_u64_t *)arg1)[i]);
113
114	return (0);
115}
116
117/*
118 * MP-friendly version of ppsratecheck().
119 *
120 * Returns non-negative if we are in the rate, negative otherwise.
121 *  0 - rate limit not reached.
122 * -1 - rate limit reached.
123 * >0 - rate limit was reached before, and was just reset. The return value
124 *      is number of events since last reset.
125 */
126int64_t
127counter_ratecheck(struct counter_rate *cr, int64_t limit)
128{
129	int64_t val;
130	int now;
131
132	val = cr->cr_over;
133	now = ticks;
134
135	if ((u_int)(now - cr->cr_ticks) >= hz) {
136		/*
137		 * Time to clear the structure, we are in the next second.
138		 * First try unlocked read, and then proceed with atomic.
139		 */
140		if ((cr->cr_lock == 0) &&
141		    atomic_cmpset_acq_int(&cr->cr_lock, 0, 1)) {
142			/*
143			 * Check if other thread has just went through the
144			 * reset sequence before us.
145			 */
146			if ((u_int)(now - cr->cr_ticks) >= hz) {
147				val = counter_u64_fetch(cr->cr_rate);
148				counter_u64_zero(cr->cr_rate);
149				cr->cr_over = 0;
150				cr->cr_ticks = now;
151				if (val <= limit)
152					val = 0;
153			}
154			atomic_store_rel_int(&cr->cr_lock, 0);
155		} else
156			/*
157			 * We failed to lock, in this case other thread may
158			 * be running counter_u64_zero(), so it is not safe
159			 * to do an update, we skip it.
160			 */
161			return (val);
162	}
163
164	counter_u64_add(cr->cr_rate, 1);
165	if (cr->cr_over != 0)
166		return (-1);
167	if (counter_u64_fetch(cr->cr_rate) > limit)
168		val = cr->cr_over = -1;
169
170	return (val);
171}
172
173void
174counter_u64_sysinit(void *arg)
175{
176	counter_u64_t *cp;
177
178	cp = arg;
179	*cp = counter_u64_alloc(M_WAITOK);
180}
181
182void
183counter_u64_sysuninit(void *arg)
184{
185	counter_u64_t *cp;
186
187	cp = arg;
188	counter_u64_free(*cp);
189}
190