xref: /freebsd/sys/kern/kern_ktr.c (revision 70e0bbedef95258a4dadc996d641a9bebd3f107d)
1 /*-
2  * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the author nor the names of any co-contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 /*
31  * This module holds the global variables used by KTR and the ktr_tracepoint()
32  * function that does the actual tracing.
33  */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include "opt_ddb.h"
39 #include "opt_ktr.h"
40 #include "opt_alq.h"
41 
42 #include <sys/param.h>
43 #include <sys/queue.h>
44 #include <sys/alq.h>
45 #include <sys/cons.h>
46 #include <sys/cpuset.h>
47 #include <sys/kernel.h>
48 #include <sys/ktr.h>
49 #include <sys/libkern.h>
50 #include <sys/proc.h>
51 #include <sys/sysctl.h>
52 #include <sys/systm.h>
53 #include <sys/time.h>
54 
55 #include <machine/cpu.h>
56 #ifdef __sparc64__
57 #include <machine/ktr.h>
58 #endif
59 
60 #ifdef DDB
61 #include <ddb/ddb.h>
62 #include <ddb/db_output.h>
63 #endif
64 
65 #ifndef KTR_ENTRIES
66 #define	KTR_ENTRIES	1024
67 #endif
68 
69 #ifndef KTR_MASK
70 #define	KTR_MASK	(0)
71 #endif
72 
73 #ifndef KTR_TIME
74 #define	KTR_TIME	get_cyclecount()
75 #endif
76 
77 #ifndef KTR_CPU
78 #define	KTR_CPU		PCPU_GET(cpuid)
79 #endif
80 
81 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
82 
83 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
84 
85 int	ktr_mask = KTR_MASK;
86 TUNABLE_INT("debug.ktr.mask", &ktr_mask);
87 SYSCTL_INT(_debug_ktr, OID_AUTO, mask, CTLFLAG_RW,
88     &ktr_mask, 0, "Bitmask of KTR event classes for which logging is enabled");
89 
90 int	ktr_compile = KTR_COMPILE;
91 SYSCTL_INT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
92     &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
93 
94 int	ktr_entries = KTR_ENTRIES;
95 SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD,
96     &ktr_entries, 0, "Number of entries in the KTR buffer");
97 
98 int	ktr_version = KTR_VERSION;
99 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
100     &ktr_version, 0, "Version of the KTR interface");
101 
102 cpuset_t ktr_cpumask;
103 static char ktr_cpumask_str[CPUSETBUFSIZ];
104 TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
105 
106 static void
107 ktr_cpumask_initializer(void *dummy __unused)
108 {
109 
110 	CPU_FILL(&ktr_cpumask);
111 #ifdef KTR_CPUMASK
112 	if (cpusetobj_strscan(&ktr_cpumask, KTR_CPUMASK) == -1)
113 		CPU_FILL(&ktr_cpumask);
114 #endif
115 
116 	/*
117 	 * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
118 	 * already set, if necessary.
119 	 */
120 	if (ktr_cpumask_str[0] != '\0' &&
121 	    cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
122 		CPU_FILL(&ktr_cpumask);
123 }
124 SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
125     ktr_cpumask_initializer, NULL);
126 
127 static int
128 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
129 {
130 	char lktr_cpumask_str[CPUSETBUFSIZ];
131 	cpuset_t imask;
132 	int error;
133 
134 	cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
135 	error = sysctl_handle_string(oidp, lktr_cpumask_str,
136 	    sizeof(lktr_cpumask_str), req);
137 	if (error != 0 || req->newptr == NULL)
138 		return (error);
139 	if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
140 		return (EINVAL);
141 	CPU_COPY(&imask, &ktr_cpumask);
142 
143 	return (error);
144 }
145 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
146     CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
147     sysctl_debug_ktr_cpumask, "S",
148     "Bitmask of CPUs on which KTR logging is enabled");
149 
150 volatile int	ktr_idx = 0;
151 struct	ktr_entry ktr_buf[KTR_ENTRIES];
152 
153 static int
154 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
155 {
156 	int clear, error;
157 
158 	clear = 0;
159 	error = sysctl_handle_int(oidp, &clear, 0, req);
160 	if (error || !req->newptr)
161 		return (error);
162 
163 	if (clear) {
164 		bzero(ktr_buf, sizeof(ktr_buf));
165 		ktr_idx = 0;
166 	}
167 
168 	return (error);
169 }
170 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
171     sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
172 
173 #ifdef KTR_VERBOSE
174 int	ktr_verbose = KTR_VERBOSE;
175 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
176 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
177 #endif
178 
179 #ifdef KTR_ALQ
180 struct alq *ktr_alq;
181 char	ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
182 int	ktr_alq_cnt = 0;
183 int	ktr_alq_depth = KTR_ENTRIES;
184 int	ktr_alq_enabled = 0;
185 int	ktr_alq_failed = 0;
186 int	ktr_alq_max = 0;
187 
188 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
189     "Maximum number of entries to write");
190 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
191     "Current number of written entries");
192 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
193     "Number of times we overran the buffer");
194 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
195     "Number of items in the write buffer");
196 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
197     sizeof(ktr_alq_file), "KTR logging file");
198 
199 static int
200 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
201 {
202 	int error;
203 	int enable;
204 
205 	enable = ktr_alq_enabled;
206 
207 	error = sysctl_handle_int(oidp, &enable, 0, req);
208 	if (error || !req->newptr)
209 		return (error);
210 
211 	if (enable) {
212 		if (ktr_alq_enabled)
213 			return (0);
214 		error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
215 		    req->td->td_ucred, ALQ_DEFAULT_CMODE,
216 		    sizeof(struct ktr_entry), ktr_alq_depth);
217 		if (error == 0) {
218 			ktr_alq_cnt = 0;
219 			ktr_alq_failed = 0;
220 			ktr_alq_enabled = 1;
221 		}
222 	} else {
223 		if (ktr_alq_enabled == 0)
224 			return (0);
225 		ktr_alq_enabled = 0;
226 		alq_close(ktr_alq);
227 		ktr_alq = NULL;
228 	}
229 
230 	return (error);
231 }
232 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
233     CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
234     "I", "Enable KTR logging");
235 #endif
236 
237 void
238 ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
239     u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
240     u_long arg6)
241 {
242 	struct ktr_entry *entry;
243 #ifdef KTR_ALQ
244 	struct ale *ale = NULL;
245 #endif
246 	int newindex, saveindex;
247 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
248 	struct thread *td;
249 #endif
250 	int cpu;
251 
252 	if (panicstr)
253 		return;
254 	if ((ktr_mask & mask) == 0)
255 		return;
256 	cpu = KTR_CPU;
257 	if (!CPU_ISSET(cpu, &ktr_cpumask))
258 		return;
259 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
260 	td = curthread;
261 	if (td->td_pflags & TDP_INKTR)
262 		return;
263 	td->td_pflags |= TDP_INKTR;
264 #endif
265 #ifdef KTR_ALQ
266 	if (ktr_alq_enabled) {
267 		if (td->td_critnest == 0 &&
268 		    (td->td_flags & TDF_IDLETD) == 0 &&
269 		    td != ald_thread) {
270 			if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
271 				goto done;
272 			if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
273 				ktr_alq_failed++;
274 				goto done;
275 			}
276 			ktr_alq_cnt++;
277 			entry = (struct ktr_entry *)ale->ae_data;
278 		} else {
279 			goto done;
280 		}
281 	} else
282 #endif
283 	{
284 		do {
285 			saveindex = ktr_idx;
286 			newindex = (saveindex + 1) & (KTR_ENTRIES - 1);
287 		} while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
288 		entry = &ktr_buf[saveindex];
289 	}
290 	entry->ktr_timestamp = KTR_TIME;
291 	entry->ktr_cpu = cpu;
292 	entry->ktr_thread = curthread;
293 	if (file != NULL)
294 		while (strncmp(file, "../", 3) == 0)
295 			file += 3;
296 	entry->ktr_file = file;
297 	entry->ktr_line = line;
298 #ifdef KTR_VERBOSE
299 	if (ktr_verbose) {
300 #ifdef SMP
301 		printf("cpu%d ", cpu);
302 #endif
303 		if (ktr_verbose > 1) {
304 			printf("%s.%d\t", entry->ktr_file,
305 			    entry->ktr_line);
306 		}
307 		printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
308 		printf("\n");
309 	}
310 #endif
311 	entry->ktr_desc = format;
312 	entry->ktr_parms[0] = arg1;
313 	entry->ktr_parms[1] = arg2;
314 	entry->ktr_parms[2] = arg3;
315 	entry->ktr_parms[3] = arg4;
316 	entry->ktr_parms[4] = arg5;
317 	entry->ktr_parms[5] = arg6;
318 #ifdef KTR_ALQ
319 	if (ktr_alq_enabled && ale)
320 		alq_post(ktr_alq, ale);
321 done:
322 #endif
323 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
324 	td->td_pflags &= ~TDP_INKTR;
325 #endif
326 }
327 
328 #ifdef DDB
329 
330 struct tstate {
331 	int	cur;
332 	int	first;
333 };
334 static	struct tstate tstate;
335 static	int db_ktr_verbose;
336 static	int db_mach_vtrace(void);
337 
338 DB_SHOW_COMMAND(ktr, db_ktr_all)
339 {
340 
341 	tstate.cur = (ktr_idx - 1) & (KTR_ENTRIES - 1);
342 	tstate.first = -1;
343 	db_ktr_verbose = 0;
344 	db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
345 	db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
346 	if (strchr(modif, 'a') != NULL) {
347 		db_disable_pager();
348 		while (cncheckc() != -1)
349 			if (db_mach_vtrace() == 0)
350 				break;
351 	} else {
352 		while (!db_pager_quit)
353 			if (db_mach_vtrace() == 0)
354 				break;
355 	}
356 }
357 
358 static int
359 db_mach_vtrace(void)
360 {
361 	struct ktr_entry	*kp;
362 
363 	if (tstate.cur == tstate.first) {
364 		db_printf("--- End of trace buffer ---\n");
365 		return (0);
366 	}
367 	kp = &ktr_buf[tstate.cur];
368 
369 	/* Skip over unused entries. */
370 	if (kp->ktr_desc == NULL) {
371 		db_printf("--- End of trace buffer ---\n");
372 		return (0);
373 	}
374 	db_printf("%d (%p", tstate.cur, kp->ktr_thread);
375 #ifdef SMP
376 	db_printf(":cpu%d", kp->ktr_cpu);
377 #endif
378 	db_printf(")");
379 	if (db_ktr_verbose >= 1) {
380 		db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
381 	}
382 	if (db_ktr_verbose >= 2) {
383 		db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
384 	}
385 	db_printf(": ");
386 	db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
387 	    kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
388 	    kp->ktr_parms[5]);
389 	db_printf("\n");
390 
391 	if (tstate.first == -1)
392 		tstate.first = tstate.cur;
393 
394 	if (--tstate.cur < 0)
395 		tstate.cur = KTR_ENTRIES - 1;
396 
397 	return (1);
398 }
399 
400 #endif	/* DDB */
401