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 #else
255 int ktr_verbose = 0;
256 #endif
257 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
258 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RWTUN, &ktr_verbose, 0,
259 "Print extra info when logging to the console");
260
261 #ifdef KTR_ALQ
262 struct alq *ktr_alq;
263 char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
264 int ktr_alq_cnt = 0;
265 int ktr_alq_depth = KTR_ENTRIES;
266 int ktr_alq_enabled = 0;
267 int ktr_alq_failed = 0;
268 int ktr_alq_max = 0;
269
270 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
271 "Maximum number of entries to write");
272 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
273 "Current number of written entries");
274 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
275 "Number of times we overran the buffer");
276 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
277 "Number of items in the write buffer");
278 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
279 sizeof(ktr_alq_file), "KTR logging file");
280
281 static int
sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)282 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
283 {
284 int error;
285 int enable;
286
287 enable = ktr_alq_enabled;
288
289 error = sysctl_handle_int(oidp, &enable, 0, req);
290 if (error || !req->newptr)
291 return (error);
292
293 if (enable) {
294 if (ktr_alq_enabled)
295 return (0);
296 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
297 req->td->td_ucred, ALQ_DEFAULT_CMODE,
298 sizeof(struct ktr_entry), ktr_alq_depth);
299 if (error == 0) {
300 ktr_alq_cnt = 0;
301 ktr_alq_failed = 0;
302 ktr_alq_enabled = 1;
303 }
304 } else {
305 if (ktr_alq_enabled == 0)
306 return (0);
307 ktr_alq_enabled = 0;
308 alq_close(ktr_alq);
309 ktr_alq = NULL;
310 }
311
312 return (error);
313 }
314 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
315 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, 0,
316 sysctl_debug_ktr_alq_enable, "I",
317 "Enable KTR logging");
318 #endif
319
320 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)321 ktr_tracepoint(uint64_t mask, const char *file, int line, const char *format,
322 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
323 u_long arg6)
324 {
325 struct ktr_entry *entry;
326 #ifdef KTR_ALQ
327 struct ale *ale = NULL;
328 #endif
329 int newindex, saveindex;
330 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
331 struct thread *td;
332 #endif
333 int cpu;
334
335 if (KERNEL_PANICKED() || kdb_active)
336 return;
337 if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
338 return;
339 cpu = KTR_CPU;
340 if (!CPU_ISSET(cpu, &ktr_cpumask))
341 return;
342 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
343 td = curthread;
344 if (td->td_pflags & TDP_INKTR)
345 return;
346 td->td_pflags |= TDP_INKTR;
347 #endif
348 #ifdef KTR_ALQ
349 if (ktr_alq_enabled) {
350 if (td->td_critnest == 0 &&
351 (TD_IS_IDLETHREAD(td)) == 0 &&
352 td != ald_thread) {
353 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
354 goto done;
355 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
356 ktr_alq_failed++;
357 goto done;
358 }
359 ktr_alq_cnt++;
360 entry = (struct ktr_entry *)ale->ae_data;
361 } else {
362 goto done;
363 }
364 } else
365 #endif
366 {
367 do {
368 saveindex = ktr_idx;
369 newindex = (saveindex + 1) % ktr_entries;
370 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
371 entry = &ktr_buf[saveindex];
372 }
373 entry->ktr_timestamp = KTR_TIME;
374 entry->ktr_cpu = cpu;
375 entry->ktr_thread = curthread;
376 if (file != NULL)
377 while (strncmp(file, "../", 3) == 0)
378 file += 3;
379 entry->ktr_file = file;
380 entry->ktr_line = line;
381 if (ktr_verbose) {
382 #ifdef SMP
383 printf("cpu%d ", cpu);
384 #endif
385 if (ktr_verbose > 1) {
386 printf("%s.%d\t", entry->ktr_file,
387 entry->ktr_line);
388 }
389 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
390 printf("\n");
391 }
392 entry->ktr_desc = format;
393 entry->ktr_parms[0] = arg1;
394 entry->ktr_parms[1] = arg2;
395 entry->ktr_parms[2] = arg3;
396 entry->ktr_parms[3] = arg4;
397 entry->ktr_parms[4] = arg5;
398 entry->ktr_parms[5] = arg6;
399 #ifdef KTR_ALQ
400 if (ktr_alq_enabled && ale)
401 alq_post(ktr_alq, ale);
402 done:
403 #endif
404 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
405 td->td_pflags &= ~TDP_INKTR;
406 #endif
407 }
408
409 #ifdef DDB
410
411 struct tstate {
412 int cur;
413 int first;
414 };
415 static struct tstate tstate;
416 static int db_ktr_verbose;
417 static int db_mach_vtrace(void);
418
DB_SHOW_COMMAND_FLAGS(ktr,db_ktr_all,DB_CMD_MEMSAFE)419 DB_SHOW_COMMAND_FLAGS(ktr, db_ktr_all, DB_CMD_MEMSAFE)
420 {
421
422 tstate.cur = (ktr_idx - 1) % ktr_entries;
423 tstate.first = -1;
424 db_ktr_verbose = 0;
425 db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
426 db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestamp please */
427 if (strchr(modif, 'a') != NULL) {
428 db_disable_pager();
429 while (cncheckc() == -1)
430 if (db_mach_vtrace() == 0)
431 break;
432 } else {
433 while (!db_pager_quit)
434 if (db_mach_vtrace() == 0)
435 break;
436 }
437 }
438
439 static int
db_mach_vtrace(void)440 db_mach_vtrace(void)
441 {
442 struct ktr_entry *kp;
443
444 if (tstate.cur == tstate.first || ktr_buf == NULL) {
445 db_printf("--- End of trace buffer ---\n");
446 return (0);
447 }
448 kp = &ktr_buf[tstate.cur];
449
450 /* Skip over unused entries. */
451 if (kp->ktr_desc == NULL) {
452 db_printf("--- End of trace buffer ---\n");
453 return (0);
454 }
455 db_printf("%d (%p", tstate.cur, kp->ktr_thread);
456 #ifdef SMP
457 db_printf(":cpu%d", kp->ktr_cpu);
458 #endif
459 db_printf(")");
460 if (db_ktr_verbose >= 1) {
461 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
462 }
463 if (db_ktr_verbose >= 2) {
464 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
465 }
466 db_printf(": ");
467 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
468 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
469 kp->ktr_parms[5]);
470 db_printf("\n");
471
472 if (tstate.first == -1)
473 tstate.first = tstate.cur;
474
475 if (--tstate.cur < 0)
476 tstate.cur = ktr_entries - 1;
477
478 return (1);
479 }
480
481 #endif /* DDB */
482