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
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_
51 struct profil_args {
52 caddr_t samples;
53 size_t size;
54 size_t offset;
55 u_int scale;
56 };
57 #endif
58 /* ARGSUSED */
59 int
sys_profil(struct thread * td,struct profil_args * uap)60 sys_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 */
110 void
addupc_intr(struct thread * td,uintfptr_t pc,u_int ticks)111 addupc_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 */
135 void
addupc_task(struct thread * td,uintfptr_t pc,u_int ticks)136 addupc_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
175 out:
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