FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_ktr.c
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: releng/10.0/sys/kern/kern_ktr.c 246530 2013-02-08 07:29:07Z avg $");
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/lock.h>
51 #include <sys/malloc.h>
52 #include <sys/mutex.h>
53 #include <sys/proc.h>
54 #include <sys/smp.h>
55 #include <sys/sysctl.h>
56 #include <sys/systm.h>
57 #include <sys/time.h>
58
59 #include <machine/cpu.h>
60 #ifdef __sparc64__
61 #include <machine/ktr.h>
62 #endif
63
64 #ifdef DDB
65 #include <ddb/ddb.h>
66 #include <ddb/db_output.h>
67 #endif
68
69 #ifndef KTR_BOOT_ENTRIES
70 #define KTR_BOOT_ENTRIES 1024
71 #endif
72
73 #ifndef KTR_ENTRIES
74 #define KTR_ENTRIES 1024
75 #endif
76
77 /* Limit the allocations to something manageable. */
78 #define KTR_ENTRIES_MAX (8 * 1024 * 1024)
79
80 #ifndef KTR_MASK
81 #define KTR_MASK (0)
82 #endif
83
84 #ifndef KTR_CPUMASK
85 #define KTR_CPUMASK CPUSET_FSET
86 #endif
87
88 #ifndef KTR_TIME
89 #define KTR_TIME get_cyclecount()
90 #endif
91
92 #ifndef KTR_CPU
93 #define KTR_CPU PCPU_GET(cpuid)
94 #endif
95
96 static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
97
98 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
99
100 volatile int ktr_idx = 0;
101 int ktr_mask = KTR_MASK;
102 int ktr_compile = KTR_COMPILE;
103 int ktr_entries = KTR_BOOT_ENTRIES;
104 int ktr_version = KTR_VERSION;
105 struct ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
106 struct ktr_entry *ktr_buf = ktr_buf_init;
107 cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
108 static char ktr_cpumask_str[CPUSETBUFSIZ];
109
110 TUNABLE_INT("debug.ktr.mask", &ktr_mask);
111
112 TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
113
114 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
115
116 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
117 &ktr_version, 0, "Version of the KTR interface");
118
119 SYSCTL_UINT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
120 &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
121
122 static void
123 ktr_cpumask_initializer(void *dummy __unused)
124 {
125
126 /*
127 * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
128 * already set, if necessary.
129 */
130 if (ktr_cpumask_str[0] != '\0' &&
131 cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
132 CPU_FILL(&ktr_cpumask);
133 }
134 SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
135 ktr_cpumask_initializer, NULL);
136
137 static int
138 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
139 {
140 char lktr_cpumask_str[CPUSETBUFSIZ];
141 cpuset_t imask;
142 int error;
143
144 cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
145 error = sysctl_handle_string(oidp, lktr_cpumask_str,
146 sizeof(lktr_cpumask_str), req);
147 if (error != 0 || req->newptr == NULL)
148 return (error);
149 if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
150 return (EINVAL);
151 CPU_COPY(&imask, &ktr_cpumask);
152
153 return (error);
154 }
155 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
156 CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
157 sysctl_debug_ktr_cpumask, "S",
158 "Bitmask of CPUs on which KTR logging is enabled");
159
160 static int
161 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
162 {
163 int clear, error;
164
165 clear = 0;
166 error = sysctl_handle_int(oidp, &clear, 0, req);
167 if (error || !req->newptr)
168 return (error);
169
170 if (clear) {
171 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
172 ktr_idx = 0;
173 }
174
175 return (error);
176 }
177 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
178 sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
179
180 /*
181 * This is a sysctl proc so that it is serialized as !MPSAFE along with
182 * the other ktr sysctl procs.
183 */
184 static int
185 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
186 {
187 int mask, error;
188
189 mask = ktr_mask;
190 error = sysctl_handle_int(oidp, &mask, 0, req);
191 if (error || !req->newptr)
192 return (error);
193 ktr_mask = mask;
194 return (error);
195 }
196
197 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_UINT|CTLFLAG_RW, 0, 0,
198 sysctl_debug_ktr_mask, "IU",
199 "Bitmask of KTR event classes for which logging is enabled");
200
201 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
202 /*
203 * A simplified version of sysctl_debug_ktr_entries.
204 * No need to care about SMP, scheduling, etc.
205 */
206 static void
207 ktr_entries_initializer(void *dummy __unused)
208 {
209 int mask;
210
211 /* Temporarily disable ktr in case malloc() is being traced. */
212 mask = ktr_mask;
213 ktr_mask = 0;
214 ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
215 M_WAITOK | M_ZERO);
216 memcpy(ktr_buf, ktr_buf_init + ktr_idx,
217 (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
218 if (ktr_idx != 0)
219 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
220 ktr_idx * sizeof(*ktr_buf));
221 ktr_entries = KTR_ENTRIES;
222 ktr_mask = mask;
223 }
224 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
225 ktr_entries_initializer, NULL);
226 #endif
227
228 static int
229 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
230 {
231 int entries, error, mask;
232 struct ktr_entry *buf, *oldbuf;
233
234 entries = ktr_entries;
235 error = sysctl_handle_int(oidp, &entries, 0, req);
236 if (error || !req->newptr)
237 return (error);
238 if (entries > KTR_ENTRIES_MAX)
239 return (ERANGE);
240 /* Disable ktr temporarily. */
241 mask = ktr_mask;
242 atomic_store_rel_int(&ktr_mask, 0);
243 /* Wait for threads to go idle. */
244 if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
245 ktr_mask = mask;
246 return (error);
247 }
248 if (ktr_buf != ktr_buf_init)
249 oldbuf = ktr_buf;
250 else
251 oldbuf = NULL;
252 /* Allocate a new buffer. */
253 buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
254 /* Install the new buffer and restart ktr. */
255 ktr_buf = buf;
256 ktr_entries = entries;
257 ktr_idx = 0;
258 atomic_store_rel_int(&ktr_mask, mask);
259 if (oldbuf != NULL)
260 free(oldbuf, M_KTR);
261
262 return (error);
263 }
264
265 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
266 sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
267
268 #ifdef KTR_VERBOSE
269 int ktr_verbose = KTR_VERBOSE;
270 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
271 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
272 #endif
273
274 #ifdef KTR_ALQ
275 struct alq *ktr_alq;
276 char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
277 int ktr_alq_cnt = 0;
278 int ktr_alq_depth = KTR_ENTRIES;
279 int ktr_alq_enabled = 0;
280 int ktr_alq_failed = 0;
281 int ktr_alq_max = 0;
282
283 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
284 "Maximum number of entries to write");
285 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
286 "Current number of written entries");
287 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
288 "Number of times we overran the buffer");
289 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
290 "Number of items in the write buffer");
291 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
292 sizeof(ktr_alq_file), "KTR logging file");
293
294 static int
295 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
296 {
297 int error;
298 int enable;
299
300 enable = ktr_alq_enabled;
301
302 error = sysctl_handle_int(oidp, &enable, 0, req);
303 if (error || !req->newptr)
304 return (error);
305
306 if (enable) {
307 if (ktr_alq_enabled)
308 return (0);
309 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
310 req->td->td_ucred, ALQ_DEFAULT_CMODE,
311 sizeof(struct ktr_entry), ktr_alq_depth);
312 if (error == 0) {
313 ktr_alq_cnt = 0;
314 ktr_alq_failed = 0;
315 ktr_alq_enabled = 1;
316 }
317 } else {
318 if (ktr_alq_enabled == 0)
319 return (0);
320 ktr_alq_enabled = 0;
321 alq_close(ktr_alq);
322 ktr_alq = NULL;
323 }
324
325 return (error);
326 }
327 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
328 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
329 "I", "Enable KTR logging");
330 #endif
331
332 void
333 ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
334 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
335 u_long arg6)
336 {
337 struct ktr_entry *entry;
338 #ifdef KTR_ALQ
339 struct ale *ale = NULL;
340 #endif
341 int newindex, saveindex;
342 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
343 struct thread *td;
344 #endif
345 int cpu;
346
347 if (panicstr)
348 return;
349 if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
350 return;
351 cpu = KTR_CPU;
352 if (!CPU_ISSET(cpu, &ktr_cpumask))
353 return;
354 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
355 td = curthread;
356 if (td->td_pflags & TDP_INKTR)
357 return;
358 td->td_pflags |= TDP_INKTR;
359 #endif
360 #ifdef KTR_ALQ
361 if (ktr_alq_enabled) {
362 if (td->td_critnest == 0 &&
363 (td->td_flags & TDF_IDLETD) == 0 &&
364 td != ald_thread) {
365 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
366 goto done;
367 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
368 ktr_alq_failed++;
369 goto done;
370 }
371 ktr_alq_cnt++;
372 entry = (struct ktr_entry *)ale->ae_data;
373 } else {
374 goto done;
375 }
376 } else
377 #endif
378 {
379 do {
380 saveindex = ktr_idx;
381 newindex = (saveindex + 1) % ktr_entries;
382 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
383 entry = &ktr_buf[saveindex];
384 }
385 entry->ktr_timestamp = KTR_TIME;
386 entry->ktr_cpu = cpu;
387 entry->ktr_thread = curthread;
388 if (file != NULL)
389 while (strncmp(file, "../", 3) == 0)
390 file += 3;
391 entry->ktr_file = file;
392 entry->ktr_line = line;
393 #ifdef KTR_VERBOSE
394 if (ktr_verbose) {
395 #ifdef SMP
396 printf("cpu%d ", cpu);
397 #endif
398 if (ktr_verbose > 1) {
399 printf("%s.%d\t", entry->ktr_file,
400 entry->ktr_line);
401 }
402 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
403 printf("\n");
404 }
405 #endif
406 entry->ktr_desc = format;
407 entry->ktr_parms[0] = arg1;
408 entry->ktr_parms[1] = arg2;
409 entry->ktr_parms[2] = arg3;
410 entry->ktr_parms[3] = arg4;
411 entry->ktr_parms[4] = arg5;
412 entry->ktr_parms[5] = arg6;
413 #ifdef KTR_ALQ
414 if (ktr_alq_enabled && ale)
415 alq_post(ktr_alq, ale);
416 done:
417 #endif
418 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
419 td->td_pflags &= ~TDP_INKTR;
420 #endif
421 }
422
423 #ifdef DDB
424
425 struct tstate {
426 int cur;
427 int first;
428 };
429 static struct tstate tstate;
430 static int db_ktr_verbose;
431 static int db_mach_vtrace(void);
432
433 DB_SHOW_COMMAND(ktr, db_ktr_all)
434 {
435
436 tstate.cur = (ktr_idx - 1) % ktr_entries;
437 tstate.first = -1;
438 db_ktr_verbose = 0;
439 db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
440 db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
441 if (strchr(modif, 'a') != NULL) {
442 db_disable_pager();
443 while (cncheckc() != -1)
444 if (db_mach_vtrace() == 0)
445 break;
446 } else {
447 while (!db_pager_quit)
448 if (db_mach_vtrace() == 0)
449 break;
450 }
451 }
452
453 static int
454 db_mach_vtrace(void)
455 {
456 struct ktr_entry *kp;
457
458 if (tstate.cur == tstate.first || ktr_buf == NULL) {
459 db_printf("--- End of trace buffer ---\n");
460 return (0);
461 }
462 kp = &ktr_buf[tstate.cur];
463
464 /* Skip over unused entries. */
465 if (kp->ktr_desc == NULL) {
466 db_printf("--- End of trace buffer ---\n");
467 return (0);
468 }
469 db_printf("%d (%p", tstate.cur, kp->ktr_thread);
470 #ifdef SMP
471 db_printf(":cpu%d", kp->ktr_cpu);
472 #endif
473 db_printf(")");
474 if (db_ktr_verbose >= 1) {
475 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
476 }
477 if (db_ktr_verbose >= 2) {
478 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
479 }
480 db_printf(": ");
481 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
482 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
483 kp->ktr_parms[5]);
484 db_printf("\n");
485
486 if (tstate.first == -1)
487 tstate.first = tstate.cur;
488
489 if (--tstate.cur < 0)
490 tstate.cur = ktr_entries - 1;
491
492 return (1);
493 }
494
495 #endif /* DDB */
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