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1/* $OpenBSD: db_prof.c,v 1.5 2021/09/03 16:45:45 jasper Exp $ */
2
3/*-
4 * Copyright (c) 1983, 1992, 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#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/proc.h>
34#include <sys/queue.h>
35#include <sys/exec_elf.h>
36#include <sys/malloc.h>
37#include <sys/gmon.h>
38
39#include <machine/db_machdep.h>
40#include <ddb/db_extern.h>
41#include <ddb/db_sym.h>
42
43#include "dt.h" /* for NDT */
44
45#if NDT > 0
46#include <dev/dt/dtvar.h>
47#endif
48
49extern int db_profile; /* Allow dynamic profiling */
50int db_prof_on; /* Profiling state On/Off */
51
52void dt_prov_kprobe_patch_all_entry(void);
53void dt_prov_kprobe_depatch_all_entry(void);
54
55vaddr_t db_get_probe_addr(struct trapframe *);
56vaddr_t db_get_pc(struct trapframe *);
57
58int
59db_prof_enable(void)
60{
61#if NDT > 0
62 if (!db_profile)
63 return EPERM;
64
65 dt_prov_kprobe_patch_all_entry();
66 db_prof_on = 1;
67 return 0;
68#else
69 return ENOENT;
70#endif /* NDT > 0 */
71}
72
73void
74db_prof_disable(void)
75{
76#if NDT > 0
77 db_prof_on = 0;
78 dt_prov_kprobe_depatch_all_entry();
79#endif /* NDT > 0 */
80}
81
82/*
83 * Equivalent to mcount(), must be called with interrupt disabled.
84 */
85void
86db_prof_count(struct trapframe *frame)
87{
88 unsigned short *frompcindex;
89 struct tostruct *top, *prevtop;
90 struct gmonparam *p;
91 long toindex;
92 unsigned long frompc, selfpc;
93
94 if ((p = curcpu()->ci_gmon) == NULL)
95 return;
96
97 /*
98 * check that we are profiling
99 * and that we aren't recursively invoked.
100 */
101 if (p->state != GMON_PROF_ON)
102 return;
103
104 frompc = db_get_pc(frame);
105 selfpc = db_get_probe_addr(frame);
106
107 /*
108 * check that frompcindex is a reasonable pc value.
109 * for example: signal catchers get called from the stack,
110 * not from text space. too bad.
111 */
112 frompc -= p->lowpc;
113 if (frompc > p->textsize)
114 return;
115
116#if (HASHFRACTION & (HASHFRACTION - 1)) == 0
117 if (p->hashfraction == HASHFRACTION)
118 frompcindex =
119 &p->froms[frompc / (HASHFRACTION * sizeof(*p->froms))];
120 else
121#endif
122 frompcindex =
123 &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))];
124 toindex = *frompcindex;
125 if (toindex == 0) {
126 /*
127 * first time traversing this arc
128 */
129 toindex = ++p->tos[0].link;
130 if (toindex >= p->tolimit)
131 /* halt further profiling */
132 goto overflow;
133
134 *frompcindex = toindex;
135 top = &p->tos[toindex];
136 top->selfpc = selfpc;
137 top->count = 1;
138 top->link = 0;
139 return;
140 }
141 top = &p->tos[toindex];
142 if (top->selfpc == selfpc) {
143 /*
144 * arc at front of chain; usual case.
145 */
146 top->count++;
147 return;
148 }
149 /*
150 * have to go looking down chain for it.
151 * top points to what we are looking at,
152 * prevtop points to previous top.
153 * we know it is not at the head of the chain.
154 */
155 for (; /* return */; ) {
156 if (top->link == 0) {
157 /*
158 * top is end of the chain and none of the chain
159 * had top->selfpc == selfpc.
160 * so we allocate a new tostruct
161 * and link it to the head of the chain.
162 */
163 toindex = ++p->tos[0].link;
164 if (toindex >= p->tolimit)
165 goto overflow;
166
167 top = &p->tos[toindex];
168 top->selfpc = selfpc;
169 top->count = 1;
170 top->link = *frompcindex;
171 *frompcindex = toindex;
172 return;
173 }
174 /*
175 * otherwise, check the next arc on the chain.
176 */
177 prevtop = top;
178 top = &p->tos[top->link];
179 if (top->selfpc == selfpc) {
180 /*
181 * there it is.
182 * increment its count
183 * move it to the head of the chain.
184 */
185 top->count++;
186 toindex = prevtop->link;
187 prevtop->link = top->link;
188 top->link = *frompcindex;
189 *frompcindex = toindex;
190 return;
191 }
192 }
193
194overflow:
195 p->state = GMON_PROF_ERROR;
196}