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