1/* $NetBSD: subr_prof.c,v 1.47 2014/07/10 21:13:52 christos Exp $ */
2
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 8.4 (Berkeley) 2/14/95
32 */
33
34#include <sys/cdefs.h>
35__KERNEL_RCSID(0, "$NetBSD: subr_prof.c,v 1.47 2014/07/10 21:13:52 christos Exp $");
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/kernel.h>
40#include <sys/proc.h>
41#include <sys/mount.h>
42#include <sys/syscallargs.h>
43#include <sys/sysctl.h>
44
45#include <sys/cpu.h>
46
47#ifdef GPROF
48#include <sys/malloc.h>
49#include <sys/gmon.h>
50
51MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");
52
53/*
54 * Froms is actually a bunch of unsigned shorts indexing tos
55 */
56struct gmonparam _gmonparam = { .state = GMON_PROF_OFF };
57
58/* Actual start of the kernel text segment. */
59extern char kernel_text[];
60
61extern char etext[];
62
63
64void
65kmstartup(void)
66{
67 char *cp;
68 struct gmonparam *p = &_gmonparam;
69 /*
70 * Round lowpc and highpc to multiples of the density we're using
71 * so the rest of the scaling (here and in gprof) stays in ints.
72 */
73 p->lowpc = rounddown(((u_long)kernel_text),
74 HISTFRACTION * sizeof(HISTCOUNTER));
75 p->highpc = roundup((u_long)etext,
76 HISTFRACTION * sizeof(HISTCOUNTER));
77 p->textsize = p->highpc - p->lowpc;
78 printf("Profiling kernel, textsize=%ld [%lx..%lx]\n",
79 p->textsize, p->lowpc, p->highpc);
80 p->kcountsize = p->textsize / HISTFRACTION;
81 p->hashfraction = HASHFRACTION;
82 p->fromssize = p->textsize / HASHFRACTION;
83 p->tolimit = p->textsize * ARCDENSITY / 100;
84 if (p->tolimit < MINARCS)
85 p->tolimit = MINARCS;
86 else if (p->tolimit > MAXARCS)
87 p->tolimit = MAXARCS;
88 p->tossize = p->tolimit * sizeof(struct tostruct);
89 cp = malloc(p->kcountsize + p->fromssize + p->tossize,
90 M_GPROF, M_NOWAIT | M_ZERO);
91 if (cp == 0) {
92 printf("No memory for profiling.\n");
93 return;
94 }
95 p->tos = (struct tostruct *)cp;
96 cp += p->tossize;
97 p->kcount = (u_short *)cp;
98 cp += p->kcountsize;
99 p->froms = (u_short *)cp;
100}
101
102/*
103 * Return kernel profiling information.
104 */
105/*
106 * sysctl helper routine for kern.profiling subtree. enables/disables
107 * kernel profiling and gives out copies of the profiling data.
108 */
109static int
110sysctl_kern_profiling(SYSCTLFN_ARGS)
111{
112 struct gmonparam *gp = &_gmonparam;
113 int error;
114 struct sysctlnode node;
115
116 node = *rnode;
117
118 switch (node.sysctl_num) {
119 case GPROF_STATE:
120 node.sysctl_data = &gp->state;
121 break;
122 case GPROF_COUNT:
123 node.sysctl_data = gp->kcount;
124 node.sysctl_size = gp->kcountsize;
125 break;
126 case GPROF_FROMS:
127 node.sysctl_data = gp->froms;
128 node.sysctl_size = gp->fromssize;
129 break;
130 case GPROF_TOS:
131 node.sysctl_data = gp->tos;
132 node.sysctl_size = gp->tossize;
133 break;
134 case GPROF_GMONPARAM:
135 node.sysctl_data = gp;
136 node.sysctl_size = sizeof(*gp);
137 break;
138 default:
139 return (EOPNOTSUPP);
140 }
141
142 error = sysctl_lookup(SYSCTLFN_CALL(&node));
143 if (error || newp == NULL)
144 return (error);
145
146 if (node.sysctl_num == GPROF_STATE) {
147 mutex_spin_enter(&proc0.p_stmutex);
148 if (gp->state == GMON_PROF_OFF)
149 stopprofclock(&proc0);
150 else
151 startprofclock(&proc0);
152 mutex_spin_exit(&proc0.p_stmutex);
153 }
154
155 return (0);
156}
157
158SYSCTL_SETUP(sysctl_kern_gprof_setup, "sysctl kern.profiling subtree setup")
159{
160
161 sysctl_createv(clog, 0, NULL, NULL,
162 CTLFLAG_PERMANENT,
163 CTLTYPE_NODE, "profiling",
164 SYSCTL_DESCR("Profiling information (available)"),
165 NULL, 0, NULL, 0,
166 CTL_KERN, KERN_PROF, CTL_EOL);
167
168 sysctl_createv(clog, 0, NULL, NULL,
169 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
170 CTLTYPE_INT, "state",
171 SYSCTL_DESCR("Profiling state"),
172 sysctl_kern_profiling, 0, NULL, 0,
173 CTL_KERN, KERN_PROF, GPROF_STATE, CTL_EOL);
174 sysctl_createv(clog, 0, NULL, NULL,
175 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
176 CTLTYPE_STRUCT, "count",
177 SYSCTL_DESCR("Array of statistical program counters"),
178 sysctl_kern_profiling, 0, NULL, 0,
179 CTL_KERN, KERN_PROF, GPROF_COUNT, CTL_EOL);
180 sysctl_createv(clog, 0, NULL, NULL,
181 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
182 CTLTYPE_STRUCT, "froms",
183 SYSCTL_DESCR("Array indexed by program counter of "
184 "call-from points"),
185 sysctl_kern_profiling, 0, NULL, 0,
186 CTL_KERN, KERN_PROF, GPROF_FROMS, CTL_EOL);
187 sysctl_createv(clog, 0, NULL, NULL,
188 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
189 CTLTYPE_STRUCT, "tos",
190 SYSCTL_DESCR("Array of structures describing "
191 "destination of calls and their counts"),
192 sysctl_kern_profiling, 0, NULL, 0,
193 CTL_KERN, KERN_PROF, GPROF_TOS, CTL_EOL);
194 sysctl_createv(clog, 0, NULL, NULL,
195 CTLFLAG_PERMANENT,
196 CTLTYPE_STRUCT, "gmonparam",
197 SYSCTL_DESCR("Structure giving the sizes of the above "
198 "arrays"),
199 sysctl_kern_profiling, 0, NULL, 0,
200 CTL_KERN, KERN_PROF, GPROF_GMONPARAM, CTL_EOL);
201}
202#endif /* GPROF */
203
204/*
205 * Profiling system call.
206 *
207 * The scale factor is a fixed point number with 16 bits of fraction, so that
208 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
209 */
210/* ARGSUSED */
211int
212sys_profil(struct lwp *l, const struct sys_profil_args *uap, register_t *retval)
213{
214 /* {
215 syscallarg(char *) samples;
216 syscallarg(size_t) size;
217 syscallarg(u_long) offset;
218 syscallarg(u_int) scale;
219 } */
220 struct proc *p = l->l_proc;
221 struct uprof *upp;
222
223 if (SCARG(uap, scale) > (1 << 16))
224 return (EINVAL);
225 if (SCARG(uap, scale) == 0) {
226 mutex_spin_enter(&p->p_stmutex);
227 stopprofclock(p);
228 mutex_spin_exit(&p->p_stmutex);
229 return (0);
230 }
231 upp = &p->p_stats->p_prof;
232
233 /* Block profile interrupts while changing state. */
234 mutex_spin_enter(&p->p_stmutex);
235 upp->pr_off = SCARG(uap, offset);
236 upp->pr_scale = SCARG(uap, scale);
237 upp->pr_base = SCARG(uap, samples);
238 upp->pr_size = SCARG(uap, size);
239 startprofclock(p);
240 mutex_spin_exit(&p->p_stmutex);
241
242 return (0);
243}
244
245/*
246 * Scale is a fixed-point number with the binary point 16 bits
247 * into the value, and is <= 1.0. pc is at most 32 bits, so the
248 * intermediate result is at most 48 bits.
249 */
250#define PC_TO_INDEX(pc, prof) \
251 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
252 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
253
254/*
255 * Collect user-level profiling statistics; called on a profiling tick,
256 * when a process is running in user-mode. This routine may be called
257 * from an interrupt context. We try to update the user profiling buffers
258 * cheaply with fuswintr() and suswintr(). If that fails, we revert to
259 * an AST that will vector us to trap() with a context in which copyin
260 * and copyout will work. Trap will then call addupc_task().
261 *
262 * Note that we may (rarely) not get around to the AST soon enough, and
263 * lose profile ticks when the next tick overwrites this one, but in this
264 * case the system is overloaded and the profile is probably already
265 * inaccurate.
266 */
267void
268addupc_intr(struct lwp *l, u_long pc)
269{
270 struct uprof *prof;
271 struct proc *p;
272 void *addr;
273 u_int i;
274 int v;
275
276 p = l->l_proc;
277
278 KASSERT(mutex_owned(&p->p_stmutex));
279
280 prof = &p->p_stats->p_prof;
281 if (pc < prof->pr_off ||
282 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
283 return; /* out of range; ignore */
284
285 addr = prof->pr_base + i;
286 mutex_spin_exit(&p->p_stmutex);
287 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + 1) == -1) {
288 /* XXXSMP */
289 prof->pr_addr = pc;
290 prof->pr_ticks++;
291 cpu_need_proftick(l);
292 }
293 mutex_spin_enter(&p->p_stmutex);
294}
295
296/*
297 * Much like before, but we can afford to take faults here. If the
298 * update fails, we simply turn off profiling.
299 */
300void
301addupc_task(struct lwp *l, u_long pc, u_int ticks)
302{
303 struct uprof *prof;
304 struct proc *p;
305 void *addr;
306 int error;
307 u_int i;
308 u_short v;
309
310 p = l->l_proc;
311
312 if (ticks == 0)
313 return;
314
315 mutex_spin_enter(&p->p_stmutex);
316 prof = &p->p_stats->p_prof;
317
318 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */
319 if ((p->p_stflag & PST_PROFIL) == 0 || pc < prof->pr_off ||
320 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) {
321 mutex_spin_exit(&p->p_stmutex);
322 return;
323 }
324
325 addr = prof->pr_base + i;
326 mutex_spin_exit(&p->p_stmutex);
327 if ((error = copyin(addr, (void *)&v, sizeof(v))) == 0) {
328 v += ticks;
329 error = copyout((void *)&v, addr, sizeof(v));
330 }
331 if (error != 0) {
332 mutex_spin_enter(&p->p_stmutex);
333 stopprofclock(p);
334 mutex_spin_exit(&p->p_stmutex);
335 }
336}
337