FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_ktr.c
1 /*-
2 * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 /*
27 * This module holds the global variables used by KTR and the ktr_tracepoint()
28 * function that does the actual tracing.
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33
34 #include "opt_ddb.h"
35 #include "opt_ktr.h"
36 #include "opt_alq.h"
37
38 #include <sys/param.h>
39 #include <sys/queue.h>
40 #include <sys/alq.h>
41 #include <sys/cons.h>
42 #include <sys/cpuset.h>
43 #include <sys/kdb.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 uint64_t ktr_mask = KTR_MASK;
96 uint64_t 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
103 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
104
105 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
106 &ktr_version, 0, "Version of the KTR interface");
107
108 SYSCTL_UQUAD(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
109 &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
110
111 static int
112 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
113 {
114 char lktr_cpumask_str[CPUSETBUFSIZ];
115 cpuset_t imask;
116 int error;
117
118 cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
119 error = sysctl_handle_string(oidp, lktr_cpumask_str,
120 sizeof(lktr_cpumask_str), req);
121 if (error != 0 || req->newptr == NULL)
122 return (error);
123 if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
124 return (EINVAL);
125 CPU_COPY(&imask, &ktr_cpumask);
126
127 return (error);
128 }
129 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
130 CTLFLAG_RWTUN | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
131 sysctl_debug_ktr_cpumask, "S",
132 "Bitmask of CPUs on which KTR logging is enabled");
133
134 static int
135 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
136 {
137 int clear, error;
138
139 clear = 0;
140 error = sysctl_handle_int(oidp, &clear, 0, req);
141 if (error || !req->newptr)
142 return (error);
143
144 if (clear) {
145 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
146 ktr_idx = 0;
147 }
148
149 return (error);
150 }
151 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
152 sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
153
154 /*
155 * This is a sysctl proc so that it is serialized as !MPSAFE along with
156 * the other ktr sysctl procs.
157 */
158 static int
159 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
160 {
161 uint64_t mask;
162 int error;
163
164 mask = ktr_mask;
165 error = sysctl_handle_64(oidp, &mask, 0, req);
166 if (error || !req->newptr)
167 return (error);
168 ktr_mask = mask;
169 return (error);
170 }
171
172 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_U64 | CTLFLAG_RWTUN, 0, 0,
173 sysctl_debug_ktr_mask, "QU",
174 "Bitmask of KTR event classes for which logging is enabled");
175
176 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
177 /*
178 * A simplified version of sysctl_debug_ktr_entries.
179 * No need to care about SMP, scheduling, etc.
180 */
181 static void
182 ktr_entries_initializer(void *dummy __unused)
183 {
184 uint64_t mask;
185
186 /* Temporarily disable ktr in case malloc() is being traced. */
187 mask = ktr_mask;
188 ktr_mask = 0;
189 ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
190 M_WAITOK | M_ZERO);
191 memcpy(ktr_buf, ktr_buf_init + ktr_idx,
192 (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
193 if (ktr_idx != 0) {
194 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
195 ktr_idx * sizeof(*ktr_buf));
196 ktr_idx = KTR_BOOT_ENTRIES;
197 }
198 ktr_entries = KTR_ENTRIES;
199 ktr_mask = mask;
200 }
201 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
202 ktr_entries_initializer, NULL);
203 #endif
204
205 static int
206 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
207 {
208 uint64_t mask;
209 int entries, error;
210 struct ktr_entry *buf, *oldbuf;
211
212 entries = ktr_entries;
213 error = sysctl_handle_int(oidp, &entries, 0, req);
214 if (error || !req->newptr)
215 return (error);
216 if (entries > KTR_ENTRIES_MAX)
217 return (ERANGE);
218 /* Disable ktr temporarily. */
219 mask = ktr_mask;
220 ktr_mask = 0;
221 /* Wait for threads to go idle. */
222 if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
223 ktr_mask = mask;
224 return (error);
225 }
226 if (ktr_buf != ktr_buf_init)
227 oldbuf = ktr_buf;
228 else
229 oldbuf = NULL;
230 /* Allocate a new buffer. */
231 buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
232 /* Install the new buffer and restart ktr. */
233 ktr_buf = buf;
234 ktr_entries = entries;
235 ktr_idx = 0;
236 ktr_mask = mask;
237 if (oldbuf != NULL)
238 free(oldbuf, M_KTR);
239
240 return (error);
241 }
242
243 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
244 sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
245
246 #ifdef KTR_VERBOSE
247 int ktr_verbose = KTR_VERBOSE;
248 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
249 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
250 #endif
251
252 #ifdef KTR_ALQ
253 struct alq *ktr_alq;
254 char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
255 int ktr_alq_cnt = 0;
256 int ktr_alq_depth = KTR_ENTRIES;
257 int ktr_alq_enabled = 0;
258 int ktr_alq_failed = 0;
259 int ktr_alq_max = 0;
260
261 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
262 "Maximum number of entries to write");
263 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
264 "Current number of written entries");
265 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
266 "Number of times we overran the buffer");
267 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
268 "Number of items in the write buffer");
269 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
270 sizeof(ktr_alq_file), "KTR logging file");
271
272 static int
273 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
274 {
275 int error;
276 int enable;
277
278 enable = ktr_alq_enabled;
279
280 error = sysctl_handle_int(oidp, &enable, 0, req);
281 if (error || !req->newptr)
282 return (error);
283
284 if (enable) {
285 if (ktr_alq_enabled)
286 return (0);
287 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
288 req->td->td_ucred, ALQ_DEFAULT_CMODE,
289 sizeof(struct ktr_entry), ktr_alq_depth);
290 if (error == 0) {
291 ktr_alq_cnt = 0;
292 ktr_alq_failed = 0;
293 ktr_alq_enabled = 1;
294 }
295 } else {
296 if (ktr_alq_enabled == 0)
297 return (0);
298 ktr_alq_enabled = 0;
299 alq_close(ktr_alq);
300 ktr_alq = NULL;
301 }
302
303 return (error);
304 }
305 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
306 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
307 "I", "Enable KTR logging");
308 #endif
309
310 void
311 ktr_tracepoint(uint64_t mask, const char *file, int line, const char *format,
312 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
313 u_long arg6)
314 {
315 struct ktr_entry *entry;
316 #ifdef KTR_ALQ
317 struct ale *ale = NULL;
318 #endif
319 int newindex, saveindex;
320 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
321 struct thread *td;
322 #endif
323 int cpu;
324
325 if (panicstr || kdb_active)
326 return;
327 if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
328 return;
329 cpu = KTR_CPU;
330 if (!CPU_ISSET(cpu, &ktr_cpumask))
331 return;
332 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
333 td = curthread;
334 if (td->td_pflags & TDP_INKTR)
335 return;
336 td->td_pflags |= TDP_INKTR;
337 #endif
338 #ifdef KTR_ALQ
339 if (ktr_alq_enabled) {
340 if (td->td_critnest == 0 &&
341 (TD_IS_IDLETHREAD(td)) == 0 &&
342 td != ald_thread) {
343 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
344 goto done;
345 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
346 ktr_alq_failed++;
347 goto done;
348 }
349 ktr_alq_cnt++;
350 entry = (struct ktr_entry *)ale->ae_data;
351 } else {
352 goto done;
353 }
354 } else
355 #endif
356 {
357 do {
358 saveindex = ktr_idx;
359 newindex = (saveindex + 1) % ktr_entries;
360 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
361 entry = &ktr_buf[saveindex];
362 }
363 entry->ktr_timestamp = KTR_TIME;
364 entry->ktr_cpu = cpu;
365 entry->ktr_thread = curthread;
366 if (file != NULL)
367 while (strncmp(file, "../", 3) == 0)
368 file += 3;
369 entry->ktr_file = file;
370 entry->ktr_line = line;
371 #ifdef KTR_VERBOSE
372 if (ktr_verbose) {
373 #ifdef SMP
374 printf("cpu%d ", cpu);
375 #endif
376 if (ktr_verbose > 1) {
377 printf("%s.%d\t", entry->ktr_file,
378 entry->ktr_line);
379 }
380 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
381 printf("\n");
382 }
383 #endif
384 entry->ktr_desc = format;
385 entry->ktr_parms[0] = arg1;
386 entry->ktr_parms[1] = arg2;
387 entry->ktr_parms[2] = arg3;
388 entry->ktr_parms[3] = arg4;
389 entry->ktr_parms[4] = arg5;
390 entry->ktr_parms[5] = arg6;
391 #ifdef KTR_ALQ
392 if (ktr_alq_enabled && ale)
393 alq_post(ktr_alq, ale);
394 done:
395 #endif
396 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
397 td->td_pflags &= ~TDP_INKTR;
398 #endif
399 }
400
401 #ifdef DDB
402
403 struct tstate {
404 int cur;
405 int first;
406 };
407 static struct tstate tstate;
408 static int db_ktr_verbose;
409 static int db_mach_vtrace(void);
410
411 DB_SHOW_COMMAND(ktr, db_ktr_all)
412 {
413
414 tstate.cur = (ktr_idx - 1) % ktr_entries;
415 tstate.first = -1;
416 db_ktr_verbose = 0;
417 db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
418 db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
419 if (strchr(modif, 'a') != NULL) {
420 db_disable_pager();
421 while (cncheckc() == -1)
422 if (db_mach_vtrace() == 0)
423 break;
424 } else {
425 while (!db_pager_quit)
426 if (db_mach_vtrace() == 0)
427 break;
428 }
429 }
430
431 static int
432 db_mach_vtrace(void)
433 {
434 struct ktr_entry *kp;
435
436 if (tstate.cur == tstate.first || ktr_buf == NULL) {
437 db_printf("--- End of trace buffer ---\n");
438 return (0);
439 }
440 kp = &ktr_buf[tstate.cur];
441
442 /* Skip over unused entries. */
443 if (kp->ktr_desc == NULL) {
444 db_printf("--- End of trace buffer ---\n");
445 return (0);
446 }
447 db_printf("%d (%p", tstate.cur, kp->ktr_thread);
448 #ifdef SMP
449 db_printf(":cpu%d", kp->ktr_cpu);
450 #endif
451 db_printf(")");
452 if (db_ktr_verbose >= 1) {
453 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
454 }
455 if (db_ktr_verbose >= 2) {
456 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
457 }
458 db_printf(": ");
459 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
460 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
461 kp->ktr_parms[5]);
462 db_printf("\n");
463
464 if (tstate.first == -1)
465 tstate.first = tstate.cur;
466
467 if (--tstate.cur < 0)
468 tstate.cur = ktr_entries - 1;
469
470 return (1);
471 }
472
473 #endif /* DDB */
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