1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1993
5 * The Regents of the University of California. 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 * 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 * @(#)subr_prof.c 8.3 (Berkeley) 9/23/93
32 */
33
34 #include <sys/cdefs.h>
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/sysproto.h>
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/mutex.h>
41 #include <sys/proc.h>
42 #include <sys/resourcevar.h>
43 #include <sys/sysctl.h>
44
45 #include <machine/cpu.h>
46
47 /*
48 * Profiling system call.
49 *
50 * The scale factor is a fixed point number with 16 bits of fraction, so that
51 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
52 */
53 #ifndef _SYS_SYSPROTO_H_
54 struct profil_args {
55 caddr_t samples;
56 size_t size;
57 size_t offset;
58 u_int scale;
59 };
60 #endif
61 /* ARGSUSED */
62 int
sys_profil(struct thread * td,struct profil_args * uap)63 sys_profil(struct thread *td, struct profil_args *uap)
64 {
65 struct uprof *upp;
66 struct proc *p;
67
68 if (uap->scale > (1 << 16))
69 return (EINVAL);
70
71 p = td->td_proc;
72 if (uap->scale == 0) {
73 PROC_LOCK(p);
74 stopprofclock(p);
75 PROC_UNLOCK(p);
76 return (0);
77 }
78 PROC_LOCK(p);
79 upp = &td->td_proc->p_stats->p_prof;
80 PROC_PROFLOCK(p);
81 upp->pr_off = uap->offset;
82 upp->pr_scale = uap->scale;
83 upp->pr_base = uap->samples;
84 upp->pr_size = uap->size;
85 PROC_PROFUNLOCK(p);
86 startprofclock(p);
87 PROC_UNLOCK(p);
88
89 return (0);
90 }
91
92 /*
93 * Scale is a fixed-point number with the binary point 16 bits
94 * into the value, and is <= 1.0. pc is at most 32 bits, so the
95 * intermediate result is at most 48 bits.
96 */
97 #define PC_TO_INDEX(pc, prof) \
98 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
99 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
100
101 /*
102 * Collect user-level profiling statistics; called on a profiling tick,
103 * when a process is running in user-mode. This routine may be called
104 * from an interrupt context. We perform the update with an AST
105 * that will vector us to trap() with a context in which copyin and
106 * copyout will work. Trap will then call addupc_task().
107 *
108 * Note that we may (rarely) not get around to the AST soon enough, and
109 * lose profile ticks when the next tick overwrites this one, but in this
110 * case the system is overloaded and the profile is probably already
111 * inaccurate.
112 */
113 void
addupc_intr(struct thread * td,uintfptr_t pc,u_int ticks)114 addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks)
115 {
116 struct uprof *prof;
117
118 if (ticks == 0)
119 return;
120 prof = &td->td_proc->p_stats->p_prof;
121 PROC_PROFLOCK(td->td_proc);
122 if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size) {
123 PROC_PROFUNLOCK(td->td_proc);
124 return; /* out of range; ignore */
125 }
126
127 PROC_PROFUNLOCK(td->td_proc);
128 td->td_profil_addr = pc;
129 td->td_profil_ticks = ticks;
130 td->td_pflags |= TDP_OWEUPC;
131 ast_sched(td, TDA_OWEUPC);
132 }
133
134 /*
135 * Actually update the profiling statistics. If the update fails, we
136 * simply turn off profiling.
137 */
138 void
addupc_task(struct thread * td,uintfptr_t pc,u_int ticks)139 addupc_task(struct thread *td, uintfptr_t pc, u_int ticks)
140 {
141 struct proc *p = td->td_proc;
142 struct uprof *prof;
143 caddr_t addr;
144 u_int i;
145 u_short v;
146 int stop = 0;
147
148 if (ticks == 0)
149 return;
150
151 PROC_LOCK(p);
152 if (!(p->p_flag & P_PROFIL)) {
153 PROC_UNLOCK(p);
154 return;
155 }
156 p->p_profthreads++;
157 prof = &p->p_stats->p_prof;
158 PROC_PROFLOCK(p);
159 if (pc < prof->pr_off ||
160 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) {
161 PROC_PROFUNLOCK(p);
162 goto out;
163 }
164
165 addr = prof->pr_base + i;
166 PROC_PROFUNLOCK(p);
167 PROC_UNLOCK(p);
168 if (copyin(addr, &v, sizeof(v)) == 0) {
169 v += ticks;
170 if (copyout(&v, addr, sizeof(v)) == 0) {
171 PROC_LOCK(p);
172 goto out;
173 }
174 }
175 stop = 1;
176 PROC_LOCK(p);
177
178 out:
179 if (--p->p_profthreads == 0) {
180 if (p->p_flag & P_STOPPROF) {
181 wakeup(&p->p_profthreads);
182 p->p_flag &= ~P_STOPPROF;
183 stop = 0;
184 }
185 }
186 if (stop)
187 stopprofclock(p);
188 PROC_UNLOCK(p);
189 }
190