FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_ktr.c
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 /*
29 * This module holds the global variables used by KTR and the ktr_tracepoint()
30 * function that does the actual tracing.
31 */
32
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35
36 #include "opt_ddb.h"
37 #include "opt_ktr.h"
38 #include "opt_alq.h"
39
40 #include <sys/param.h>
41 #include <sys/queue.h>
42 #include <sys/alq.h>
43 #include <sys/cons.h>
44 #include <sys/cpuset.h>
45 #include <sys/kdb.h>
46 #include <sys/kernel.h>
47 #include <sys/ktr.h>
48 #include <sys/libkern.h>
49 #include <sys/lock.h>
50 #include <sys/malloc.h>
51 #include <sys/mutex.h>
52 #include <sys/proc.h>
53 #include <sys/smp.h>
54 #include <sys/sysctl.h>
55 #include <sys/systm.h>
56 #include <sys/time.h>
57
58 #include <machine/cpu.h>
59
60 #ifdef DDB
61 #include <ddb/ddb.h>
62 #include <ddb/db_output.h>
63 #endif
64
65 #ifndef KTR_BOOT_ENTRIES
66 #define KTR_BOOT_ENTRIES 1024
67 #endif
68
69 #ifndef KTR_ENTRIES
70 #define KTR_ENTRIES 1024
71 #endif
72
73 /* Limit the allocations to something manageable. */
74 #define KTR_ENTRIES_MAX (8 * 1024 * 1024)
75
76 #ifndef KTR_MASK
77 #define KTR_MASK (0)
78 #endif
79
80 #ifndef KTR_CPUMASK
81 #define KTR_CPUMASK CPUSET_FSET
82 #endif
83
84 #ifndef KTR_TIME
85 #define KTR_TIME get_cyclecount()
86 #endif
87
88 #ifndef KTR_CPU
89 #define KTR_CPU PCPU_GET(cpuid)
90 #endif
91
92 static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
93
94 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
95
96 volatile int ktr_idx = 0;
97 uint64_t ktr_mask = KTR_MASK;
98 uint64_t ktr_compile = KTR_COMPILE;
99 int ktr_entries = KTR_BOOT_ENTRIES;
100 int ktr_version = KTR_VERSION;
101 struct ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
102 struct ktr_entry *ktr_buf = ktr_buf_init;
103 cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
104
105 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
106
107 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
108 &ktr_version, 0, "Version of the KTR interface");
109
110 SYSCTL_UQUAD(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
111 &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
112
113 static int
114 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
115 {
116 char lktr_cpumask_str[CPUSETBUFSIZ];
117 cpuset_t imask;
118 int error;
119
120 cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
121 error = sysctl_handle_string(oidp, lktr_cpumask_str,
122 sizeof(lktr_cpumask_str), req);
123 if (error != 0 || req->newptr == NULL)
124 return (error);
125 if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
126 return (EINVAL);
127 CPU_COPY(&imask, &ktr_cpumask);
128
129 return (error);
130 }
131 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
132 CTLFLAG_RWTUN | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
133 sysctl_debug_ktr_cpumask, "S",
134 "Bitmask of CPUs on which KTR logging is enabled");
135
136 static int
137 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
138 {
139 int clear, error;
140
141 clear = 0;
142 error = sysctl_handle_int(oidp, &clear, 0, req);
143 if (error || !req->newptr)
144 return (error);
145
146 if (clear) {
147 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
148 ktr_idx = 0;
149 }
150
151 return (error);
152 }
153 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
154 sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
155
156 /*
157 * This is a sysctl proc so that it is serialized as !MPSAFE along with
158 * the other ktr sysctl procs.
159 */
160 static int
161 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
162 {
163 uint64_t mask;
164 int error;
165
166 mask = ktr_mask;
167 error = sysctl_handle_64(oidp, &mask, 0, req);
168 if (error || !req->newptr)
169 return (error);
170 ktr_mask = mask;
171 return (error);
172 }
173
174 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_U64 | CTLFLAG_RWTUN, 0, 0,
175 sysctl_debug_ktr_mask, "QU",
176 "Bitmask of KTR event classes for which logging is enabled");
177
178 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
179 /*
180 * A simplified version of sysctl_debug_ktr_entries.
181 * No need to care about SMP, scheduling, etc.
182 */
183 static void
184 ktr_entries_initializer(void *dummy __unused)
185 {
186 uint64_t mask;
187
188 /* Temporarily disable ktr in case malloc() is being traced. */
189 mask = ktr_mask;
190 ktr_mask = 0;
191 ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
192 M_WAITOK | M_ZERO);
193 memcpy(ktr_buf, ktr_buf_init + ktr_idx,
194 (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
195 if (ktr_idx != 0) {
196 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
197 ktr_idx * sizeof(*ktr_buf));
198 ktr_idx = KTR_BOOT_ENTRIES;
199 }
200 ktr_entries = KTR_ENTRIES;
201 ktr_mask = mask;
202 }
203 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
204 ktr_entries_initializer, NULL);
205 #endif
206
207 static int
208 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
209 {
210 uint64_t mask;
211 int entries, error;
212 struct ktr_entry *buf, *oldbuf;
213
214 entries = ktr_entries;
215 error = sysctl_handle_int(oidp, &entries, 0, req);
216 if (error || !req->newptr)
217 return (error);
218 if (entries > KTR_ENTRIES_MAX)
219 return (ERANGE);
220 /* Disable ktr temporarily. */
221 mask = ktr_mask;
222 ktr_mask = 0;
223 /* Wait for threads to go idle. */
224 if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
225 ktr_mask = mask;
226 return (error);
227 }
228 if (ktr_buf != ktr_buf_init)
229 oldbuf = ktr_buf;
230 else
231 oldbuf = NULL;
232 /* Allocate a new buffer. */
233 buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
234 /* Install the new buffer and restart ktr. */
235 ktr_buf = buf;
236 ktr_entries = entries;
237 ktr_idx = 0;
238 ktr_mask = mask;
239 if (oldbuf != NULL)
240 free(oldbuf, M_KTR);
241
242 return (error);
243 }
244
245 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
246 sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
247
248 #ifdef KTR_VERBOSE
249 int ktr_verbose = KTR_VERBOSE;
250 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
251 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
252 #endif
253
254 #ifdef KTR_ALQ
255 struct alq *ktr_alq;
256 char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
257 int ktr_alq_cnt = 0;
258 int ktr_alq_depth = KTR_ENTRIES;
259 int ktr_alq_enabled = 0;
260 int ktr_alq_failed = 0;
261 int ktr_alq_max = 0;
262
263 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
264 "Maximum number of entries to write");
265 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
266 "Current number of written entries");
267 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
268 "Number of times we overran the buffer");
269 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
270 "Number of items in the write buffer");
271 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
272 sizeof(ktr_alq_file), "KTR logging file");
273
274 static int
275 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
276 {
277 int error;
278 int enable;
279
280 enable = ktr_alq_enabled;
281
282 error = sysctl_handle_int(oidp, &enable, 0, req);
283 if (error || !req->newptr)
284 return (error);
285
286 if (enable) {
287 if (ktr_alq_enabled)
288 return (0);
289 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
290 req->td->td_ucred, ALQ_DEFAULT_CMODE,
291 sizeof(struct ktr_entry), ktr_alq_depth);
292 if (error == 0) {
293 ktr_alq_cnt = 0;
294 ktr_alq_failed = 0;
295 ktr_alq_enabled = 1;
296 }
297 } else {
298 if (ktr_alq_enabled == 0)
299 return (0);
300 ktr_alq_enabled = 0;
301 alq_close(ktr_alq);
302 ktr_alq = NULL;
303 }
304
305 return (error);
306 }
307 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
308 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
309 "I", "Enable KTR logging");
310 #endif
311
312 void
313 ktr_tracepoint(uint64_t mask, const char *file, int line, const char *format,
314 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
315 u_long arg6)
316 {
317 struct ktr_entry *entry;
318 #ifdef KTR_ALQ
319 struct ale *ale = NULL;
320 #endif
321 int newindex, saveindex;
322 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
323 struct thread *td;
324 #endif
325 int cpu;
326
327 if (panicstr || kdb_active)
328 return;
329 if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
330 return;
331 cpu = KTR_CPU;
332 if (!CPU_ISSET(cpu, &ktr_cpumask))
333 return;
334 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
335 td = curthread;
336 if (td->td_pflags & TDP_INKTR)
337 return;
338 td->td_pflags |= TDP_INKTR;
339 #endif
340 #ifdef KTR_ALQ
341 if (ktr_alq_enabled) {
342 if (td->td_critnest == 0 &&
343 (TD_IS_IDLETHREAD(td)) == 0 &&
344 td != ald_thread) {
345 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
346 goto done;
347 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
348 ktr_alq_failed++;
349 goto done;
350 }
351 ktr_alq_cnt++;
352 entry = (struct ktr_entry *)ale->ae_data;
353 } else {
354 goto done;
355 }
356 } else
357 #endif
358 {
359 do {
360 saveindex = ktr_idx;
361 newindex = (saveindex + 1) % ktr_entries;
362 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
363 entry = &ktr_buf[saveindex];
364 }
365 entry->ktr_timestamp = KTR_TIME;
366 entry->ktr_cpu = cpu;
367 entry->ktr_thread = curthread;
368 if (file != NULL)
369 while (strncmp(file, "../", 3) == 0)
370 file += 3;
371 entry->ktr_file = file;
372 entry->ktr_line = line;
373 #ifdef KTR_VERBOSE
374 if (ktr_verbose) {
375 #ifdef SMP
376 printf("cpu%d ", cpu);
377 #endif
378 if (ktr_verbose > 1) {
379 printf("%s.%d\t", entry->ktr_file,
380 entry->ktr_line);
381 }
382 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
383 printf("\n");
384 }
385 #endif
386 entry->ktr_desc = format;
387 entry->ktr_parms[0] = arg1;
388 entry->ktr_parms[1] = arg2;
389 entry->ktr_parms[2] = arg3;
390 entry->ktr_parms[3] = arg4;
391 entry->ktr_parms[4] = arg5;
392 entry->ktr_parms[5] = arg6;
393 #ifdef KTR_ALQ
394 if (ktr_alq_enabled && ale)
395 alq_post(ktr_alq, ale);
396 done:
397 #endif
398 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
399 td->td_pflags &= ~TDP_INKTR;
400 #endif
401 }
402
403 #ifdef DDB
404
405 struct tstate {
406 int cur;
407 int first;
408 };
409 static struct tstate tstate;
410 static int db_ktr_verbose;
411 static int db_mach_vtrace(void);
412
413 DB_SHOW_COMMAND(ktr, db_ktr_all)
414 {
415
416 tstate.cur = (ktr_idx - 1) % ktr_entries;
417 tstate.first = -1;
418 db_ktr_verbose = 0;
419 db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
420 db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestamp please */
421 if (strchr(modif, 'a') != NULL) {
422 db_disable_pager();
423 while (cncheckc() == -1)
424 if (db_mach_vtrace() == 0)
425 break;
426 } else {
427 while (!db_pager_quit)
428 if (db_mach_vtrace() == 0)
429 break;
430 }
431 }
432
433 static int
434 db_mach_vtrace(void)
435 {
436 struct ktr_entry *kp;
437
438 if (tstate.cur == tstate.first || ktr_buf == NULL) {
439 db_printf("--- End of trace buffer ---\n");
440 return (0);
441 }
442 kp = &ktr_buf[tstate.cur];
443
444 /* Skip over unused entries. */
445 if (kp->ktr_desc == NULL) {
446 db_printf("--- End of trace buffer ---\n");
447 return (0);
448 }
449 db_printf("%d (%p", tstate.cur, kp->ktr_thread);
450 #ifdef SMP
451 db_printf(":cpu%d", kp->ktr_cpu);
452 #endif
453 db_printf(")");
454 if (db_ktr_verbose >= 1) {
455 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
456 }
457 if (db_ktr_verbose >= 2) {
458 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
459 }
460 db_printf(": ");
461 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
462 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
463 kp->ktr_parms[5]);
464 db_printf("\n");
465
466 if (tstate.first == -1)
467 tstate.first = tstate.cur;
468
469 if (--tstate.cur < 0)
470 tstate.cur = ktr_entries - 1;
471
472 return (1);
473 }
474
475 #endif /* DDB */
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