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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 /*
28 * This module holds the global variables used by KTR and the ktr_tracepoint()
29 * function that does the actual tracing.
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34
35 #include "opt_ddb.h"
36 #include "opt_ktr.h"
37 #include "opt_alq.h"
38
39 #include <sys/param.h>
40 #include <sys/queue.h>
41 #include <sys/alq.h>
42 #include <sys/cons.h>
43 #include <sys/cpuset.h>
44 #include <sys/kernel.h>
45 #include <sys/ktr.h>
46 #include <sys/libkern.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/mutex.h>
50 #include <sys/proc.h>
51 #include <sys/smp.h>
52 #include <sys/sysctl.h>
53 #include <sys/systm.h>
54 #include <sys/time.h>
55
56 #include <machine/cpu.h>
57
58 #ifdef DDB
59 #include <ddb/ddb.h>
60 #include <ddb/db_output.h>
61 #endif
62
63 #ifndef KTR_BOOT_ENTRIES
64 #define KTR_BOOT_ENTRIES 1024
65 #endif
66
67 #ifndef KTR_ENTRIES
68 #define KTR_ENTRIES 1024
69 #endif
70
71 /* Limit the allocations to something manageable. */
72 #define KTR_ENTRIES_MAX (8 * 1024 * 1024)
73
74 #ifndef KTR_MASK
75 #define KTR_MASK (0)
76 #endif
77
78 #ifndef KTR_CPUMASK
79 #define KTR_CPUMASK CPUSET_FSET
80 #endif
81
82 #ifndef KTR_TIME
83 #define KTR_TIME get_cyclecount()
84 #endif
85
86 #ifndef KTR_CPU
87 #define KTR_CPU PCPU_GET(cpuid)
88 #endif
89
90 static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
91
92 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
93
94 volatile int ktr_idx = 0;
95 int ktr_mask = KTR_MASK;
96 int ktr_compile = KTR_COMPILE;
97 int ktr_entries = KTR_BOOT_ENTRIES;
98 int ktr_version = KTR_VERSION;
99 struct ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
100 struct ktr_entry *ktr_buf = ktr_buf_init;
101 cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
102 static char ktr_cpumask_str[CPUSETBUFSIZ];
103
104 TUNABLE_INT("debug.ktr.mask", &ktr_mask);
105
106 TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
107
108 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
109
110 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
111 &ktr_version, 0, "Version of the KTR interface");
112
113 SYSCTL_UINT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
114 &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
115
116 static void
117 ktr_cpumask_initializer(void *dummy __unused)
118 {
119
120 /*
121 * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
122 * already set, if necessary.
123 */
124 if (ktr_cpumask_str[0] != '\0' &&
125 cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
126 CPU_FILL(&ktr_cpumask);
127 }
128 SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
129 ktr_cpumask_initializer, NULL);
130
131 static int
132 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
133 {
134 char lktr_cpumask_str[CPUSETBUFSIZ];
135 cpuset_t imask;
136 int error;
137
138 cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
139 error = sysctl_handle_string(oidp, lktr_cpumask_str,
140 sizeof(lktr_cpumask_str), req);
141 if (error != 0 || req->newptr == NULL)
142 return (error);
143 if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
144 return (EINVAL);
145 CPU_COPY(&imask, &ktr_cpumask);
146
147 return (error);
148 }
149 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
150 CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
151 sysctl_debug_ktr_cpumask, "S",
152 "Bitmask of CPUs on which KTR logging is enabled");
153
154 static int
155 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
156 {
157 int clear, error;
158
159 clear = 0;
160 error = sysctl_handle_int(oidp, &clear, 0, req);
161 if (error || !req->newptr)
162 return (error);
163
164 if (clear) {
165 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
166 ktr_idx = 0;
167 }
168
169 return (error);
170 }
171 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
172 sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
173
174 /*
175 * This is a sysctl proc so that it is serialized as !MPSAFE along with
176 * the other ktr sysctl procs.
177 */
178 static int
179 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
180 {
181 int mask, error;
182
183 mask = ktr_mask;
184 error = sysctl_handle_int(oidp, &mask, 0, req);
185 if (error || !req->newptr)
186 return (error);
187 ktr_mask = mask;
188 return (error);
189 }
190
191 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_UINT|CTLFLAG_RW, 0, 0,
192 sysctl_debug_ktr_mask, "IU",
193 "Bitmask of KTR event classes for which logging is enabled");
194
195 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
196 /*
197 * A simplified version of sysctl_debug_ktr_entries.
198 * No need to care about SMP, scheduling, etc.
199 */
200 static void
201 ktr_entries_initializer(void *dummy __unused)
202 {
203 int mask;
204
205 /* Temporarily disable ktr in case malloc() is being traced. */
206 mask = ktr_mask;
207 ktr_mask = 0;
208 ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
209 M_WAITOK | M_ZERO);
210 memcpy(ktr_buf, ktr_buf_init + ktr_idx,
211 (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
212 if (ktr_idx != 0)
213 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
214 ktr_idx * sizeof(*ktr_buf));
215 ktr_entries = KTR_ENTRIES;
216 ktr_mask = mask;
217 }
218 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
219 ktr_entries_initializer, NULL);
220 #endif
221
222 static int
223 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
224 {
225 int entries, error, mask;
226 struct ktr_entry *buf, *oldbuf;
227
228 entries = ktr_entries;
229 error = sysctl_handle_int(oidp, &entries, 0, req);
230 if (error || !req->newptr)
231 return (error);
232 if (entries > KTR_ENTRIES_MAX)
233 return (ERANGE);
234 /* Disable ktr temporarily. */
235 mask = ktr_mask;
236 atomic_store_rel_int(&ktr_mask, 0);
237 /* Wait for threads to go idle. */
238 if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
239 ktr_mask = mask;
240 return (error);
241 }
242 if (ktr_buf != ktr_buf_init)
243 oldbuf = ktr_buf;
244 else
245 oldbuf = NULL;
246 /* Allocate a new buffer. */
247 buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
248 /* Install the new buffer and restart ktr. */
249 ktr_buf = buf;
250 ktr_entries = entries;
251 ktr_idx = 0;
252 atomic_store_rel_int(&ktr_mask, mask);
253 if (oldbuf != NULL)
254 free(oldbuf, M_KTR);
255
256 return (error);
257 }
258
259 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
260 sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
261
262 #ifdef KTR_VERBOSE
263 int ktr_verbose = KTR_VERBOSE;
264 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
265 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
266 #endif
267
268 #ifdef KTR_ALQ
269 struct alq *ktr_alq;
270 char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
271 int ktr_alq_cnt = 0;
272 int ktr_alq_depth = KTR_ENTRIES;
273 int ktr_alq_enabled = 0;
274 int ktr_alq_failed = 0;
275 int ktr_alq_max = 0;
276
277 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
278 "Maximum number of entries to write");
279 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
280 "Current number of written entries");
281 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
282 "Number of times we overran the buffer");
283 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
284 "Number of items in the write buffer");
285 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
286 sizeof(ktr_alq_file), "KTR logging file");
287
288 static int
289 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
290 {
291 int error;
292 int enable;
293
294 enable = ktr_alq_enabled;
295
296 error = sysctl_handle_int(oidp, &enable, 0, req);
297 if (error || !req->newptr)
298 return (error);
299
300 if (enable) {
301 if (ktr_alq_enabled)
302 return (0);
303 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
304 req->td->td_ucred, ALQ_DEFAULT_CMODE,
305 sizeof(struct ktr_entry), ktr_alq_depth);
306 if (error == 0) {
307 ktr_alq_cnt = 0;
308 ktr_alq_failed = 0;
309 ktr_alq_enabled = 1;
310 }
311 } else {
312 if (ktr_alq_enabled == 0)
313 return (0);
314 ktr_alq_enabled = 0;
315 alq_close(ktr_alq);
316 ktr_alq = NULL;
317 }
318
319 return (error);
320 }
321 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
322 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
323 "I", "Enable KTR logging");
324 #endif
325
326 void
327 ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
328 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
329 u_long arg6)
330 {
331 struct ktr_entry *entry;
332 #ifdef KTR_ALQ
333 struct ale *ale = NULL;
334 #endif
335 int newindex, saveindex;
336 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
337 struct thread *td;
338 #endif
339 int cpu;
340
341 if (panicstr)
342 return;
343 if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
344 return;
345 cpu = KTR_CPU;
346 if (!CPU_ISSET(cpu, &ktr_cpumask))
347 return;
348 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
349 td = curthread;
350 if (td->td_pflags & TDP_INKTR)
351 return;
352 td->td_pflags |= TDP_INKTR;
353 #endif
354 #ifdef KTR_ALQ
355 if (ktr_alq_enabled) {
356 if (td->td_critnest == 0 &&
357 (td->td_flags & TDF_IDLETD) == 0 &&
358 td != ald_thread) {
359 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
360 goto done;
361 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
362 ktr_alq_failed++;
363 goto done;
364 }
365 ktr_alq_cnt++;
366 entry = (struct ktr_entry *)ale->ae_data;
367 } else {
368 goto done;
369 }
370 } else
371 #endif
372 {
373 do {
374 saveindex = ktr_idx;
375 newindex = (saveindex + 1) % ktr_entries;
376 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
377 entry = &ktr_buf[saveindex];
378 }
379 entry->ktr_timestamp = KTR_TIME;
380 entry->ktr_cpu = cpu;
381 entry->ktr_thread = curthread;
382 if (file != NULL)
383 while (strncmp(file, "../", 3) == 0)
384 file += 3;
385 entry->ktr_file = file;
386 entry->ktr_line = line;
387 #ifdef KTR_VERBOSE
388 if (ktr_verbose) {
389 #ifdef SMP
390 printf("cpu%d ", cpu);
391 #endif
392 if (ktr_verbose > 1) {
393 printf("%s.%d\t", entry->ktr_file,
394 entry->ktr_line);
395 }
396 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
397 printf("\n");
398 }
399 #endif
400 entry->ktr_desc = format;
401 entry->ktr_parms[0] = arg1;
402 entry->ktr_parms[1] = arg2;
403 entry->ktr_parms[2] = arg3;
404 entry->ktr_parms[3] = arg4;
405 entry->ktr_parms[4] = arg5;
406 entry->ktr_parms[5] = arg6;
407 #ifdef KTR_ALQ
408 if (ktr_alq_enabled && ale)
409 alq_post(ktr_alq, ale);
410 done:
411 #endif
412 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
413 td->td_pflags &= ~TDP_INKTR;
414 #endif
415 }
416
417 #ifdef DDB
418
419 struct tstate {
420 int cur;
421 int first;
422 };
423 static struct tstate tstate;
424 static int db_ktr_verbose;
425 static int db_mach_vtrace(void);
426
427 DB_SHOW_COMMAND(ktr, db_ktr_all)
428 {
429
430 tstate.cur = (ktr_idx - 1) % ktr_entries;
431 tstate.first = -1;
432 db_ktr_verbose = 0;
433 db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
434 db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
435 if (strchr(modif, 'a') != NULL) {
436 db_disable_pager();
437 while (cncheckc() != -1)
438 if (db_mach_vtrace() == 0)
439 break;
440 } else {
441 while (!db_pager_quit)
442 if (db_mach_vtrace() == 0)
443 break;
444 }
445 }
446
447 static int
448 db_mach_vtrace(void)
449 {
450 struct ktr_entry *kp;
451
452 if (tstate.cur == tstate.first || ktr_buf == NULL) {
453 db_printf("--- End of trace buffer ---\n");
454 return (0);
455 }
456 kp = &ktr_buf[tstate.cur];
457
458 /* Skip over unused entries. */
459 if (kp->ktr_desc == NULL) {
460 db_printf("--- End of trace buffer ---\n");
461 return (0);
462 }
463 db_printf("%d (%p", tstate.cur, kp->ktr_thread);
464 #ifdef SMP
465 db_printf(":cpu%d", kp->ktr_cpu);
466 #endif
467 db_printf(")");
468 if (db_ktr_verbose >= 1) {
469 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
470 }
471 if (db_ktr_verbose >= 2) {
472 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
473 }
474 db_printf(": ");
475 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
476 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
477 kp->ktr_parms[5]);
478 db_printf("\n");
479
480 if (tstate.first == -1)
481 tstate.first = tstate.cur;
482
483 if (--tstate.cur < 0)
484 tstate.cur = ktr_entries - 1;
485
486 return (1);
487 }
488
489 #endif /* DDB */
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