1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 #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 | CTLFLAG_MPSAFE, 0,
104 "KTR options");
105
106 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
107 &ktr_version, 0, "Version of the KTR interface");
108
109 SYSCTL_UQUAD(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
110 &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
111
112 static int
sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)113 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
114 {
115 char lktr_cpumask_str[CPUSETBUFSIZ];
116 cpuset_t imask;
117 int error;
118
119 cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
120 error = sysctl_handle_string(oidp, lktr_cpumask_str,
121 sizeof(lktr_cpumask_str), req);
122 if (error != 0 || req->newptr == NULL)
123 return (error);
124 if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
125 return (EINVAL);
126 CPU_COPY(&imask, &ktr_cpumask);
127
128 return (error);
129 }
130 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
131 CTLFLAG_RWTUN | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
132 sysctl_debug_ktr_cpumask, "S",
133 "Bitmask of CPUs on which KTR logging is enabled");
134
135 static int
sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)136 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
137 {
138 int clear, error;
139
140 clear = 0;
141 error = sysctl_handle_int(oidp, &clear, 0, req);
142 if (error || !req->newptr)
143 return (error);
144
145 if (clear) {
146 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
147 ktr_idx = 0;
148 }
149
150 return (error);
151 }
152 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear,
153 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, 0,
154 sysctl_debug_ktr_clear, "I",
155 "Clear KTR Buffer");
156
157 /*
158 * This is a sysctl proc so that it is serialized as !MPSAFE along with
159 * the other ktr sysctl procs.
160 */
161 static int
sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)162 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
163 {
164 uint64_t mask;
165 int error;
166
167 mask = ktr_mask;
168 error = sysctl_handle_64(oidp, &mask, 0, req);
169 if (error || !req->newptr)
170 return (error);
171 ktr_mask = mask;
172 return (error);
173 }
174
175 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask,
176 CTLTYPE_U64 | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT,
177 0, 0, sysctl_debug_ktr_mask, "QU",
178 "Bitmask of KTR event classes for which logging is enabled");
179
180 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
181 /*
182 * A simplified version of sysctl_debug_ktr_entries.
183 * No need to care about SMP, scheduling, etc.
184 */
185 static void
ktr_entries_initializer(void * dummy __unused)186 ktr_entries_initializer(void *dummy __unused)
187 {
188 uint64_t mask;
189
190 /* Temporarily disable ktr in case malloc() is being traced. */
191 mask = ktr_mask;
192 ktr_mask = 0;
193 ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
194 M_WAITOK | M_ZERO);
195 memcpy(ktr_buf, ktr_buf_init + ktr_idx,
196 (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
197 if (ktr_idx != 0) {
198 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
199 ktr_idx * sizeof(*ktr_buf));
200 ktr_idx = KTR_BOOT_ENTRIES;
201 }
202 ktr_entries = KTR_ENTRIES;
203 ktr_mask = mask;
204 }
205 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
206 ktr_entries_initializer, NULL);
207 #endif
208
209 static int
sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)210 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
211 {
212 uint64_t mask;
213 int entries, error;
214 struct ktr_entry *buf, *oldbuf;
215
216 entries = ktr_entries;
217 error = sysctl_handle_int(oidp, &entries, 0, req);
218 if (error || !req->newptr)
219 return (error);
220 if (entries > KTR_ENTRIES_MAX)
221 return (ERANGE);
222 /* Disable ktr temporarily. */
223 mask = ktr_mask;
224 ktr_mask = 0;
225 /* Wait for threads to go idle. */
226 if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
227 ktr_mask = mask;
228 return (error);
229 }
230 if (ktr_buf != ktr_buf_init)
231 oldbuf = ktr_buf;
232 else
233 oldbuf = NULL;
234 /* Allocate a new buffer. */
235 buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
236 /* Install the new buffer and restart ktr. */
237 ktr_buf = buf;
238 ktr_entries = entries;
239 ktr_idx = 0;
240 ktr_mask = mask;
241 if (oldbuf != NULL)
242 free(oldbuf, M_KTR);
243
244 return (error);
245 }
246
247 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries,
248 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
249 0, 0, sysctl_debug_ktr_entries, "I",
250 "Number of entries in the KTR buffer");
251
252 #ifdef KTR_VERBOSE
253 int ktr_verbose = KTR_VERBOSE;
254 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
255 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
256 #endif
257
258 #ifdef KTR_ALQ
259 struct alq *ktr_alq;
260 char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
261 int ktr_alq_cnt = 0;
262 int ktr_alq_depth = KTR_ENTRIES;
263 int ktr_alq_enabled = 0;
264 int ktr_alq_failed = 0;
265 int ktr_alq_max = 0;
266
267 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
268 "Maximum number of entries to write");
269 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
270 "Current number of written entries");
271 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
272 "Number of times we overran the buffer");
273 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
274 "Number of items in the write buffer");
275 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
276 sizeof(ktr_alq_file), "KTR logging file");
277
278 static int
sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)279 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
280 {
281 int error;
282 int enable;
283
284 enable = ktr_alq_enabled;
285
286 error = sysctl_handle_int(oidp, &enable, 0, req);
287 if (error || !req->newptr)
288 return (error);
289
290 if (enable) {
291 if (ktr_alq_enabled)
292 return (0);
293 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
294 req->td->td_ucred, ALQ_DEFAULT_CMODE,
295 sizeof(struct ktr_entry), ktr_alq_depth);
296 if (error == 0) {
297 ktr_alq_cnt = 0;
298 ktr_alq_failed = 0;
299 ktr_alq_enabled = 1;
300 }
301 } else {
302 if (ktr_alq_enabled == 0)
303 return (0);
304 ktr_alq_enabled = 0;
305 alq_close(ktr_alq);
306 ktr_alq = NULL;
307 }
308
309 return (error);
310 }
311 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
312 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, 0,
313 sysctl_debug_ktr_alq_enable, "I",
314 "Enable KTR logging");
315 #endif
316
317 void
ktr_tracepoint(uint64_t mask,const char * file,int line,const char * format,u_long arg1,u_long arg2,u_long arg3,u_long arg4,u_long arg5,u_long arg6)318 ktr_tracepoint(uint64_t mask, const char *file, int line, const char *format,
319 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
320 u_long arg6)
321 {
322 struct ktr_entry *entry;
323 #ifdef KTR_ALQ
324 struct ale *ale = NULL;
325 #endif
326 int newindex, saveindex;
327 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
328 struct thread *td;
329 #endif
330 int cpu;
331
332 if (KERNEL_PANICKED() || kdb_active)
333 return;
334 if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
335 return;
336 cpu = KTR_CPU;
337 if (!CPU_ISSET(cpu, &ktr_cpumask))
338 return;
339 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
340 td = curthread;
341 if (td->td_pflags & TDP_INKTR)
342 return;
343 td->td_pflags |= TDP_INKTR;
344 #endif
345 #ifdef KTR_ALQ
346 if (ktr_alq_enabled) {
347 if (td->td_critnest == 0 &&
348 (TD_IS_IDLETHREAD(td)) == 0 &&
349 td != ald_thread) {
350 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
351 goto done;
352 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
353 ktr_alq_failed++;
354 goto done;
355 }
356 ktr_alq_cnt++;
357 entry = (struct ktr_entry *)ale->ae_data;
358 } else {
359 goto done;
360 }
361 } else
362 #endif
363 {
364 do {
365 saveindex = ktr_idx;
366 newindex = (saveindex + 1) % ktr_entries;
367 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
368 entry = &ktr_buf[saveindex];
369 }
370 entry->ktr_timestamp = KTR_TIME;
371 entry->ktr_cpu = cpu;
372 entry->ktr_thread = curthread;
373 if (file != NULL)
374 while (strncmp(file, "../", 3) == 0)
375 file += 3;
376 entry->ktr_file = file;
377 entry->ktr_line = line;
378 #ifdef KTR_VERBOSE
379 if (ktr_verbose) {
380 #ifdef SMP
381 printf("cpu%d ", cpu);
382 #endif
383 if (ktr_verbose > 1) {
384 printf("%s.%d\t", entry->ktr_file,
385 entry->ktr_line);
386 }
387 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
388 printf("\n");
389 }
390 #endif
391 entry->ktr_desc = format;
392 entry->ktr_parms[0] = arg1;
393 entry->ktr_parms[1] = arg2;
394 entry->ktr_parms[2] = arg3;
395 entry->ktr_parms[3] = arg4;
396 entry->ktr_parms[4] = arg5;
397 entry->ktr_parms[5] = arg6;
398 #ifdef KTR_ALQ
399 if (ktr_alq_enabled && ale)
400 alq_post(ktr_alq, ale);
401 done:
402 #endif
403 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
404 td->td_pflags &= ~TDP_INKTR;
405 #endif
406 }
407
408 #ifdef DDB
409
410 struct tstate {
411 int cur;
412 int first;
413 };
414 static struct tstate tstate;
415 static int db_ktr_verbose;
416 static int db_mach_vtrace(void);
417
DB_SHOW_COMMAND_FLAGS(ktr,db_ktr_all,DB_CMD_MEMSAFE)418 DB_SHOW_COMMAND_FLAGS(ktr, db_ktr_all, DB_CMD_MEMSAFE)
419 {
420
421 tstate.cur = (ktr_idx - 1) % ktr_entries;
422 tstate.first = -1;
423 db_ktr_verbose = 0;
424 db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
425 db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestamp please */
426 if (strchr(modif, 'a') != NULL) {
427 db_disable_pager();
428 while (cncheckc() == -1)
429 if (db_mach_vtrace() == 0)
430 break;
431 } else {
432 while (!db_pager_quit)
433 if (db_mach_vtrace() == 0)
434 break;
435 }
436 }
437
438 static int
db_mach_vtrace(void)439 db_mach_vtrace(void)
440 {
441 struct ktr_entry *kp;
442
443 if (tstate.cur == tstate.first || ktr_buf == NULL) {
444 db_printf("--- End of trace buffer ---\n");
445 return (0);
446 }
447 kp = &ktr_buf[tstate.cur];
448
449 /* Skip over unused entries. */
450 if (kp->ktr_desc == NULL) {
451 db_printf("--- End of trace buffer ---\n");
452 return (0);
453 }
454 db_printf("%d (%p", tstate.cur, kp->ktr_thread);
455 #ifdef SMP
456 db_printf(":cpu%d", kp->ktr_cpu);
457 #endif
458 db_printf(")");
459 if (db_ktr_verbose >= 1) {
460 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
461 }
462 if (db_ktr_verbose >= 2) {
463 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
464 }
465 db_printf(": ");
466 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
467 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
468 kp->ktr_parms[5]);
469 db_printf("\n");
470
471 if (tstate.first == -1)
472 tstate.first = tstate.cur;
473
474 if (--tstate.cur < 0)
475 tstate.cur = ktr_entries - 1;
476
477 return (1);
478 }
479
480 #endif /* DDB */
481