1187692Snwhitehorn/*-
2187692Snwhitehorn * SPDX-License-Identifier: BSD-3-Clause
3187692Snwhitehorn *
4187692Snwhitehorn * Copyright (c) 1982, 1986, 1993
5187692Snwhitehorn *	The Regents of the University of California.  All rights reserved.
6187692Snwhitehorn *
7187692Snwhitehorn * Redistribution and use in source and binary forms, with or without
8187692Snwhitehorn * modification, are permitted provided that the following conditions
9187692Snwhitehorn * are met:
10187692Snwhitehorn * 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 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/sysproto.h>
35#include <sys/kernel.h>
36#include <sys/lock.h>
37#include <sys/mutex.h>
38#include <sys/proc.h>
39#include <sys/resourcevar.h>
40#include <sys/sysctl.h>
41
42#include <machine/cpu.h>
43
44/*
45 * Profiling system call.
46 *
47 * The scale factor is a fixed point number with 16 bits of fraction, so that
48 * 1.0 is represented as 0x10000.  A scale factor of 0 turns off profiling.
49 */
50#ifndef _SYS_SYSPROTO_H_
51struct profil_args {
52	caddr_t	samples;
53	size_t	size;
54	size_t	offset;
55	u_int	scale;
56};
57#endif
58/* ARGSUSED */
59int
60sys_profil(struct thread *td, struct profil_args *uap)
61{
62	struct uprof *upp;
63	struct proc *p;
64
65	if (uap->scale > (1 << 16))
66		return (EINVAL);
67
68	p = td->td_proc;
69	if (uap->scale == 0) {
70		PROC_LOCK(p);
71		stopprofclock(p);
72		PROC_UNLOCK(p);
73		return (0);
74	}
75	PROC_LOCK(p);
76	upp = &td->td_proc->p_stats->p_prof;
77	PROC_PROFLOCK(p);
78	upp->pr_off = uap->offset;
79	upp->pr_scale = uap->scale;
80	upp->pr_base = uap->samples;
81	upp->pr_size = uap->size;
82	PROC_PROFUNLOCK(p);
83	startprofclock(p);
84	PROC_UNLOCK(p);
85
86	return (0);
87}
88
89/*
90 * Scale is a fixed-point number with the binary point 16 bits
91 * into the value, and is <= 1.0.  pc is at most 32 bits, so the
92 * intermediate result is at most 48 bits.
93 */
94#define	PC_TO_INDEX(pc, prof) \
95	((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
96	    (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
97
98/*
99 * Collect user-level profiling statistics; called on a profiling tick,
100 * when a process is running in user-mode.  This routine may be called
101 * from an interrupt context.  We perform the update with an AST
102 * that will vector us to trap() with a context in which copyin and
103 * copyout will work.  Trap will then call addupc_task().
104 *
105 * Note that we may (rarely) not get around to the AST soon enough, and
106 * lose profile ticks when the next tick overwrites this one, but in this
107 * case the system is overloaded and the profile is probably already
108 * inaccurate.
109 */
110void
111addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks)
112{
113	struct uprof *prof;
114
115	if (ticks == 0)
116		return;
117	prof = &td->td_proc->p_stats->p_prof;
118	PROC_PROFLOCK(td->td_proc);
119	if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size) {
120		PROC_PROFUNLOCK(td->td_proc);
121		return;			/* out of range; ignore */
122	}
123
124	PROC_PROFUNLOCK(td->td_proc);
125	td->td_profil_addr = pc;
126	td->td_profil_ticks = ticks;
127	td->td_pflags |= TDP_OWEUPC;
128	ast_sched(td, TDA_OWEUPC);
129}
130
131/*
132 * Actually update the profiling statistics.  If the update fails, we
133 * simply turn off profiling.
134 */
135void
136addupc_task(struct thread *td, uintfptr_t pc, u_int ticks)
137{
138	struct proc *p = td->td_proc;
139	struct uprof *prof;
140	caddr_t addr;
141	u_int i;
142	u_short v;
143	int stop = 0;
144
145	if (ticks == 0)
146		return;
147
148	PROC_LOCK(p);
149	if (!(p->p_flag & P_PROFIL)) {
150		PROC_UNLOCK(p);
151		return;
152	}
153	p->p_profthreads++;
154	prof = &p->p_stats->p_prof;
155	PROC_PROFLOCK(p);
156	if (pc < prof->pr_off ||
157	    (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) {
158		PROC_PROFUNLOCK(p);
159		goto out;
160	}
161
162	addr = prof->pr_base + i;
163	PROC_PROFUNLOCK(p);
164	PROC_UNLOCK(p);
165	if (copyin(addr, &v, sizeof(v)) == 0) {
166		v += ticks;
167		if (copyout(&v, addr, sizeof(v)) == 0) {
168			PROC_LOCK(p);
169			goto out;
170		}
171	}
172	stop = 1;
173	PROC_LOCK(p);
174
175out:
176	if (--p->p_profthreads == 0) {
177		if (p->p_flag & P_STOPPROF) {
178			wakeup(&p->p_profthreads);
179			p->p_flag &= ~P_STOPPROF;
180			stop = 0;
181		}
182	}
183	if (stop)
184		stopprofclock(p);
185	PROC_UNLOCK(p);
186}
187