1/* $NetBSD: mcount.c,v 1.13 2016/02/28 02:56:39 christos Exp $ */
2
3/*
4 * Copyright (c) 2003, 2004 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Nathan J. Williams for Wasabi Systems, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed for the NetBSD Project by
20 * Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 * or promote products derived from this software without specific prior
23 * written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38/*-
39 * Copyright (c) 1983, 1992, 1993
40 * The Regents of the University of California. All rights reserved.
41 *
42 * Redistribution and use in source and binary forms, with or without
43 * modification, are permitted provided that the following conditions
44 * are met:
45 * 1. Redistributions of source code must retain the above copyright
46 * notice, this list of conditions and the following disclaimer.
47 * 2. Redistributions in binary form must reproduce the above copyright
48 * notice, this list of conditions and the following disclaimer in the
49 * documentation and/or other materials provided with the distribution.
50 * 3. Neither the name of the University nor the names of its contributors
51 * may be used to endorse or promote products derived from this software
52 * without specific prior written permission.
53 *
54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64 * SUCH DAMAGE.
65 */
66
67/* If building a standalone libkern, don't include mcount. */
68#if (!defined(_KERNEL) || defined(GPROF)) && !defined(_STANDALONE)
69
70#ifdef _KERNEL_OPT
71#include "opt_multiprocessor.h"
72#endif
73
74#include <sys/cdefs.h>
75#if !defined(lint) && !defined(_KERNEL) && defined(LIBC_SCCS)
76#if 0
77static char sccsid[] = "@(#)mcount.c 8.1 (Berkeley) 6/4/93";
78#else
79__RCSID("$NetBSD: mcount.c,v 1.13 2016/02/28 02:56:39 christos Exp $");
80#endif
81#endif
82
83#include <sys/param.h>
84#include <sys/gmon.h>
85#include <sys/lock.h>
86
87#ifndef _KERNEL
88#include "reentrant.h"
89#endif
90
91#ifdef _REENTRANT
92extern thread_key_t _gmonkey;
93extern struct gmonparam _gmondummy;
94struct gmonparam *_m_gmon_alloc(void);
95#endif
96
97#if defined(_KERNEL) && !defined(_RUMPKERNEL) && defined(MULTIPROCESSOR)
98__cpu_simple_lock_t __mcount_lock;
99#endif
100
101#ifndef __LINT__
102_MCOUNT_DECL(u_long, u_long)
103#ifdef _KERNEL
104 __attribute__((__no_instrument_function__))
105#endif
106 __used;
107#endif
108
109/* XXX: make these interfaces */
110#ifdef _RUMPKERNEL
111#undef MCOUNT_ENTER
112#define MCOUNT_ENTER
113#undef MCOUNT_EXIT
114#define MCOUNT_EXIT
115#undef MCOUNT
116#define MCOUNT
117#endif
118
119/*
120 * mcount is called on entry to each function compiled with the profiling
121 * switch set. _mcount(), which is declared in a machine-dependent way
122 * with _MCOUNT_DECL, does the actual work and is either inlined into a
123 * C routine or called by an assembly stub. In any case, this magic is
124 * taken care of by the MCOUNT definition in <machine/profile.h>.
125 *
126 * _mcount updates data structures that represent traversals of the
127 * program's call graph edges. frompc and selfpc are the return
128 * address and function address that represents the given call graph edge.
129 *
130 * Note: the original BSD code used the same variable (frompcindex) for
131 * both frompcindex and frompc. Any reasonable, modern compiler will
132 * perform this optimization.
133 */
134#ifndef __LINT__
135/* _mcount; may be static, inline, etc */
136_MCOUNT_DECL(u_long frompc, u_long selfpc)
137{
138 u_short *frompcindex;
139 struct tostruct *top, *prevtop;
140 struct gmonparam *p;
141 long toindex;
142#if defined(_KERNEL) && !defined(_RUMPKERNEL)
143 int s;
144#endif
145
146#if defined(_REENTRANT) && !defined(_KERNEL)
147 if (__isthreaded) {
148 /* prevent re-entry via thr_getspecific */
149 if (_gmonparam.state != GMON_PROF_ON)
150 return;
151 _gmonparam.state = GMON_PROF_BUSY;
152 p = thr_getspecific(_gmonkey);
153 if (p == NULL) {
154 /* Prevent recursive calls while allocating */
155 thr_setspecific(_gmonkey, &_gmondummy);
156 p = _m_gmon_alloc();
157 }
158 _gmonparam.state = GMON_PROF_ON;
159 } else
160#endif
161 p = &_gmonparam;
162 /*
163 * check that we are profiling
164 * and that we aren't recursively invoked.
165 */
166 if (p->state != GMON_PROF_ON)
167 return;
168#if defined(_KERNEL) && !defined(_RUMPKERNEL)
169 MCOUNT_ENTER;
170#ifdef MULTIPROCESSOR
171 __cpu_simple_lock(&__mcount_lock);
172 __insn_barrier();
173#endif
174#endif
175 p->state = GMON_PROF_BUSY;
176 /*
177 * check that frompcindex is a reasonable pc value.
178 * for example: signal catchers get called from the stack,
179 * not from text space. too bad.
180 */
181 frompc -= p->lowpc;
182 if (frompc > p->textsize)
183 goto done;
184
185#if (HASHFRACTION & (HASHFRACTION - 1)) == 0
186 if (p->hashfraction == HASHFRACTION)
187 frompcindex =
188 &p->froms[
189 (size_t)(frompc / (HASHFRACTION * sizeof(*p->froms)))];
190 else
191#endif
192 frompcindex =
193 &p->froms[
194 (size_t)(frompc / (p->hashfraction * sizeof(*p->froms)))];
195 toindex = *frompcindex;
196 if (toindex == 0) {
197 /*
198 * first time traversing this arc
199 */
200 toindex = ++p->tos[0].link;
201 if (toindex >= p->tolimit)
202 /* halt further profiling */
203 goto overflow;
204
205 *frompcindex = (u_short)toindex;
206 top = &p->tos[(size_t)toindex];
207 top->selfpc = selfpc;
208 top->count = 1;
209 top->link = 0;
210 goto done;
211 }
212 top = &p->tos[(size_t)toindex];
213 if (top->selfpc == selfpc) {
214 /*
215 * arc at front of chain; usual case.
216 */
217 top->count++;
218 goto done;
219 }
220 /*
221 * have to go looking down chain for it.
222 * top points to what we are looking at,
223 * prevtop points to previous top.
224 * we know it is not at the head of the chain.
225 */
226 for (; /* goto done */; ) {
227 if (top->link == 0) {
228 /*
229 * top is end of the chain and none of the chain
230 * had top->selfpc == selfpc.
231 * so we allocate a new tostruct
232 * and link it to the head of the chain.
233 */
234 toindex = ++p->tos[0].link;
235 if (toindex >= p->tolimit)
236 goto overflow;
237
238 top = &p->tos[(size_t)toindex];
239 top->selfpc = selfpc;
240 top->count = 1;
241 top->link = *frompcindex;
242 *frompcindex = (u_short)toindex;
243 goto done;
244 }
245 /*
246 * otherwise, check the next arc on the chain.
247 */
248 prevtop = top;
249 top = &p->tos[top->link];
250 if (top->selfpc == selfpc) {
251 /*
252 * there it is.
253 * increment its count
254 * move it to the head of the chain.
255 */
256 top->count++;
257 toindex = prevtop->link;
258 prevtop->link = top->link;
259 top->link = *frompcindex;
260 *frompcindex = (u_short)toindex;
261 goto done;
262 }
263 }
264done:
265 p->state = GMON_PROF_ON;
266#if defined(_KERNEL) && !defined(_RUMPKERNEL)
267#ifdef MULTIPROCESSOR
268 __insn_barrier();
269 __cpu_simple_unlock(&__mcount_lock);
270#endif
271 MCOUNT_EXIT;
272#endif
273 return;
274
275overflow:
276 p->state = GMON_PROF_ERROR;
277#if defined(_KERNEL) && !defined(_RUMPKERNEL)
278#ifdef MULTIPROCESSOR
279 __insn_barrier();
280 __cpu_simple_unlock(&__mcount_lock);
281#endif
282 MCOUNT_EXIT;
283#endif
284 return;
285}
286#endif
287
288#ifdef MCOUNT
289/*
290 * Actual definition of mcount function. Defined in <machine/profile.h>,
291 * which is included by <sys/gmon.h>.
292 */
293MCOUNT
294#endif
295
296#endif /* (!_KERNEL || GPROF) && !_STANDALONE */
297