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: releng/10.2/sys/kern/kern_ktr.c 262192 2014-02-18 20:27:17Z jhb $");
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 #ifdef __sparc64__
58 #include <machine/ktr.h>
59 #endif
60
61 #ifdef DDB
62 #include <ddb/ddb.h>
63 #include <ddb/db_output.h>
64 #endif
65
66 #ifndef KTR_BOOT_ENTRIES
67 #define KTR_BOOT_ENTRIES 1024
68 #endif
69
70 #ifndef KTR_ENTRIES
71 #define KTR_ENTRIES 1024
72 #endif
73
74 /* Limit the allocations to something manageable. */
75 #define KTR_ENTRIES_MAX (8 * 1024 * 1024)
76
77 #ifndef KTR_MASK
78 #define KTR_MASK (0)
79 #endif
80
81 #ifndef KTR_CPUMASK
82 #define KTR_CPUMASK CPUSET_FSET
83 #endif
84
85 #ifndef KTR_TIME
86 #define KTR_TIME get_cyclecount()
87 #endif
88
89 #ifndef KTR_CPU
90 #define KTR_CPU PCPU_GET(cpuid)
91 #endif
92
93 static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
94
95 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
96
97 volatile int ktr_idx = 0;
98 int ktr_mask = KTR_MASK;
99 int ktr_compile = KTR_COMPILE;
100 int ktr_entries = KTR_BOOT_ENTRIES;
101 int ktr_version = KTR_VERSION;
102 struct ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
103 struct ktr_entry *ktr_buf = ktr_buf_init;
104 cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
105 static char ktr_cpumask_str[CPUSETBUFSIZ];
106
107 TUNABLE_INT("debug.ktr.mask", &ktr_mask);
108
109 TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
110
111 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
112
113 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
114 &ktr_version, 0, "Version of the KTR interface");
115
116 SYSCTL_UINT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
117 &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
118
119 static void
120 ktr_cpumask_initializer(void *dummy __unused)
121 {
122
123 /*
124 * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
125 * already set, if necessary.
126 */
127 if (ktr_cpumask_str[0] != '\0' &&
128 cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
129 CPU_FILL(&ktr_cpumask);
130 }
131 SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
132 ktr_cpumask_initializer, NULL);
133
134 static int
135 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
136 {
137 char lktr_cpumask_str[CPUSETBUFSIZ];
138 cpuset_t imask;
139 int error;
140
141 cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
142 error = sysctl_handle_string(oidp, lktr_cpumask_str,
143 sizeof(lktr_cpumask_str), req);
144 if (error != 0 || req->newptr == NULL)
145 return (error);
146 if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
147 return (EINVAL);
148 CPU_COPY(&imask, &ktr_cpumask);
149
150 return (error);
151 }
152 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
153 CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
154 sysctl_debug_ktr_cpumask, "S",
155 "Bitmask of CPUs on which KTR logging is enabled");
156
157 static int
158 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
159 {
160 int clear, error;
161
162 clear = 0;
163 error = sysctl_handle_int(oidp, &clear, 0, req);
164 if (error || !req->newptr)
165 return (error);
166
167 if (clear) {
168 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
169 ktr_idx = 0;
170 }
171
172 return (error);
173 }
174 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
175 sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
176
177 /*
178 * This is a sysctl proc so that it is serialized as !MPSAFE along with
179 * the other ktr sysctl procs.
180 */
181 static int
182 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
183 {
184 int mask, error;
185
186 mask = ktr_mask;
187 error = sysctl_handle_int(oidp, &mask, 0, req);
188 if (error || !req->newptr)
189 return (error);
190 ktr_mask = mask;
191 return (error);
192 }
193
194 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_UINT|CTLFLAG_RW, 0, 0,
195 sysctl_debug_ktr_mask, "IU",
196 "Bitmask of KTR event classes for which logging is enabled");
197
198 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
199 /*
200 * A simplified version of sysctl_debug_ktr_entries.
201 * No need to care about SMP, scheduling, etc.
202 */
203 static void
204 ktr_entries_initializer(void *dummy __unused)
205 {
206 int mask;
207
208 /* Temporarily disable ktr in case malloc() is being traced. */
209 mask = ktr_mask;
210 ktr_mask = 0;
211 ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
212 M_WAITOK | M_ZERO);
213 memcpy(ktr_buf, ktr_buf_init + ktr_idx,
214 (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
215 if (ktr_idx != 0)
216 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
217 ktr_idx * sizeof(*ktr_buf));
218 ktr_entries = KTR_ENTRIES;
219 ktr_mask = mask;
220 }
221 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
222 ktr_entries_initializer, NULL);
223 #endif
224
225 static int
226 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
227 {
228 int entries, error, mask;
229 struct ktr_entry *buf, *oldbuf;
230
231 entries = ktr_entries;
232 error = sysctl_handle_int(oidp, &entries, 0, req);
233 if (error || !req->newptr)
234 return (error);
235 if (entries > KTR_ENTRIES_MAX)
236 return (ERANGE);
237 /* Disable ktr temporarily. */
238 mask = ktr_mask;
239 atomic_store_rel_int(&ktr_mask, 0);
240 /* Wait for threads to go idle. */
241 if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
242 ktr_mask = mask;
243 return (error);
244 }
245 if (ktr_buf != ktr_buf_init)
246 oldbuf = ktr_buf;
247 else
248 oldbuf = NULL;
249 /* Allocate a new buffer. */
250 buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
251 /* Install the new buffer and restart ktr. */
252 ktr_buf = buf;
253 ktr_entries = entries;
254 ktr_idx = 0;
255 atomic_store_rel_int(&ktr_mask, mask);
256 if (oldbuf != NULL)
257 free(oldbuf, M_KTR);
258
259 return (error);
260 }
261
262 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
263 sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
264
265 #ifdef KTR_VERBOSE
266 int ktr_verbose = KTR_VERBOSE;
267 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
268 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
269 #endif
270
271 #ifdef KTR_ALQ
272 struct alq *ktr_alq;
273 char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
274 int ktr_alq_cnt = 0;
275 int ktr_alq_depth = KTR_ENTRIES;
276 int ktr_alq_enabled = 0;
277 int ktr_alq_failed = 0;
278 int ktr_alq_max = 0;
279
280 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
281 "Maximum number of entries to write");
282 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
283 "Current number of written entries");
284 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
285 "Number of times we overran the buffer");
286 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
287 "Number of items in the write buffer");
288 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
289 sizeof(ktr_alq_file), "KTR logging file");
290
291 static int
292 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
293 {
294 int error;
295 int enable;
296
297 enable = ktr_alq_enabled;
298
299 error = sysctl_handle_int(oidp, &enable, 0, req);
300 if (error || !req->newptr)
301 return (error);
302
303 if (enable) {
304 if (ktr_alq_enabled)
305 return (0);
306 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
307 req->td->td_ucred, ALQ_DEFAULT_CMODE,
308 sizeof(struct ktr_entry), ktr_alq_depth);
309 if (error == 0) {
310 ktr_alq_cnt = 0;
311 ktr_alq_failed = 0;
312 ktr_alq_enabled = 1;
313 }
314 } else {
315 if (ktr_alq_enabled == 0)
316 return (0);
317 ktr_alq_enabled = 0;
318 alq_close(ktr_alq);
319 ktr_alq = NULL;
320 }
321
322 return (error);
323 }
324 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
325 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
326 "I", "Enable KTR logging");
327 #endif
328
329 void
330 ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
331 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
332 u_long arg6)
333 {
334 struct ktr_entry *entry;
335 #ifdef KTR_ALQ
336 struct ale *ale = NULL;
337 #endif
338 int newindex, saveindex;
339 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
340 struct thread *td;
341 #endif
342 int cpu;
343
344 if (panicstr)
345 return;
346 if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
347 return;
348 cpu = KTR_CPU;
349 if (!CPU_ISSET(cpu, &ktr_cpumask))
350 return;
351 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
352 td = curthread;
353 if (td->td_pflags & TDP_INKTR)
354 return;
355 td->td_pflags |= TDP_INKTR;
356 #endif
357 #ifdef KTR_ALQ
358 if (ktr_alq_enabled) {
359 if (td->td_critnest == 0 &&
360 (td->td_flags & TDF_IDLETD) == 0 &&
361 td != ald_thread) {
362 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
363 goto done;
364 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
365 ktr_alq_failed++;
366 goto done;
367 }
368 ktr_alq_cnt++;
369 entry = (struct ktr_entry *)ale->ae_data;
370 } else {
371 goto done;
372 }
373 } else
374 #endif
375 {
376 do {
377 saveindex = ktr_idx;
378 newindex = (saveindex + 1) % ktr_entries;
379 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
380 entry = &ktr_buf[saveindex];
381 }
382 entry->ktr_timestamp = KTR_TIME;
383 entry->ktr_cpu = cpu;
384 entry->ktr_thread = curthread;
385 if (file != NULL)
386 while (strncmp(file, "../", 3) == 0)
387 file += 3;
388 entry->ktr_file = file;
389 entry->ktr_line = line;
390 #ifdef KTR_VERBOSE
391 if (ktr_verbose) {
392 #ifdef SMP
393 printf("cpu%d ", cpu);
394 #endif
395 if (ktr_verbose > 1) {
396 printf("%s.%d\t", entry->ktr_file,
397 entry->ktr_line);
398 }
399 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
400 printf("\n");
401 }
402 #endif
403 entry->ktr_desc = format;
404 entry->ktr_parms[0] = arg1;
405 entry->ktr_parms[1] = arg2;
406 entry->ktr_parms[2] = arg3;
407 entry->ktr_parms[3] = arg4;
408 entry->ktr_parms[4] = arg5;
409 entry->ktr_parms[5] = arg6;
410 #ifdef KTR_ALQ
411 if (ktr_alq_enabled && ale)
412 alq_post(ktr_alq, ale);
413 done:
414 #endif
415 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
416 td->td_pflags &= ~TDP_INKTR;
417 #endif
418 }
419
420 #ifdef DDB
421
422 struct tstate {
423 int cur;
424 int first;
425 };
426 static struct tstate tstate;
427 static int db_ktr_verbose;
428 static int db_mach_vtrace(void);
429
430 DB_SHOW_COMMAND(ktr, db_ktr_all)
431 {
432
433 tstate.cur = (ktr_idx - 1) % ktr_entries;
434 tstate.first = -1;
435 db_ktr_verbose = 0;
436 db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
437 db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
438 if (strchr(modif, 'a') != NULL) {
439 db_disable_pager();
440 while (cncheckc() != -1)
441 if (db_mach_vtrace() == 0)
442 break;
443 } else {
444 while (!db_pager_quit)
445 if (db_mach_vtrace() == 0)
446 break;
447 }
448 }
449
450 static int
451 db_mach_vtrace(void)
452 {
453 struct ktr_entry *kp;
454
455 if (tstate.cur == tstate.first || ktr_buf == NULL) {
456 db_printf("--- End of trace buffer ---\n");
457 return (0);
458 }
459 kp = &ktr_buf[tstate.cur];
460
461 /* Skip over unused entries. */
462 if (kp->ktr_desc == NULL) {
463 db_printf("--- End of trace buffer ---\n");
464 return (0);
465 }
466 db_printf("%d (%p", tstate.cur, kp->ktr_thread);
467 #ifdef SMP
468 db_printf(":cpu%d", kp->ktr_cpu);
469 #endif
470 db_printf(")");
471 if (db_ktr_verbose >= 1) {
472 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
473 }
474 if (db_ktr_verbose >= 2) {
475 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
476 }
477 db_printf(": ");
478 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
479 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
480 kp->ktr_parms[5]);
481 db_printf("\n");
482
483 if (tstate.first == -1)
484 tstate.first = tstate.cur;
485
486 if (--tstate.cur < 0)
487 tstate.cur = ktr_entries - 1;
488
489 return (1);
490 }
491
492 #endif /* DDB */
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