kern_ktr.c revision 262192 
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: stable/10/sys/kern/kern_ktr.c 262192 2014-02-18 20:27:17Z jhb $");
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#ifdef __sparc64__
58#include <machine/ktr.h>
59#endif
60
61#ifdef DDB
62#include <ddb/ddb.h>
63#include <ddb/db_output.h>
64#endif
65
66#ifndef KTR_BOOT_ENTRIES
67#define	KTR_BOOT_ENTRIES	1024
68#endif
69
70#ifndef KTR_ENTRIES
71#define	KTR_ENTRIES	1024
72#endif
73
74/* Limit the allocations to something manageable. */
75#define	KTR_ENTRIES_MAX	(8 * 1024 * 1024)
76
77#ifndef KTR_MASK
78#define	KTR_MASK	(0)
79#endif
80
81#ifndef KTR_CPUMASK
82#define	KTR_CPUMASK	CPUSET_FSET
83#endif
84
85#ifndef KTR_TIME
86#define	KTR_TIME	get_cyclecount()
87#endif
88
89#ifndef KTR_CPU
90#define	KTR_CPU		PCPU_GET(cpuid)
91#endif
92
93static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
94
95FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
96
97volatile int	ktr_idx = 0;
98int	ktr_mask = KTR_MASK;
99int	ktr_compile = KTR_COMPILE;
100int	ktr_entries = KTR_BOOT_ENTRIES;
101int	ktr_version = KTR_VERSION;
102struct	ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
103struct	ktr_entry *ktr_buf = ktr_buf_init;
104cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
105static char ktr_cpumask_str[CPUSETBUFSIZ];
106
107TUNABLE_INT("debug.ktr.mask", &ktr_mask);
108
109TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
110
111static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
112
113SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
114    &ktr_version, 0, "Version of the KTR interface");
115
116SYSCTL_UINT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
117    &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
118
119static void
120ktr_cpumask_initializer(void *dummy __unused)
121{
122
123	/*
124	 * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
125	 * already set, if necessary.
126	 */
127	if (ktr_cpumask_str[0] != '\0' &&
128	    cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
129		CPU_FILL(&ktr_cpumask);
130}
131SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
132    ktr_cpumask_initializer, NULL);
133
134static int
135sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
136{
137	char lktr_cpumask_str[CPUSETBUFSIZ];
138	cpuset_t imask;
139	int error;
140
141	cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
142	error = sysctl_handle_string(oidp, lktr_cpumask_str,
143	    sizeof(lktr_cpumask_str), req);
144	if (error != 0 || req->newptr == NULL)
145		return (error);
146	if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
147		return (EINVAL);
148	CPU_COPY(&imask, &ktr_cpumask);
149
150	return (error);
151}
152SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
153    CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
154    sysctl_debug_ktr_cpumask, "S",
155    "Bitmask of CPUs on which KTR logging is enabled");
156
157static int
158sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
159{
160	int clear, error;
161
162	clear = 0;
163	error = sysctl_handle_int(oidp, &clear, 0, req);
164	if (error || !req->newptr)
165		return (error);
166
167	if (clear) {
168		bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
169		ktr_idx = 0;
170	}
171
172	return (error);
173}
174SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
175    sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
176
177/*
178 * This is a sysctl proc so that it is serialized as !MPSAFE along with
179 * the other ktr sysctl procs.
180 */
181static int
182sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
183{
184	int mask, error;
185
186	mask = ktr_mask;
187	error = sysctl_handle_int(oidp, &mask, 0, req);
188	if (error || !req->newptr)
189		return (error);
190	ktr_mask = mask;
191	return (error);
192}
193
194SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_UINT|CTLFLAG_RW, 0, 0,
195    sysctl_debug_ktr_mask, "IU",
196    "Bitmask of KTR event classes for which logging is enabled");
197
198#if KTR_ENTRIES > KTR_BOOT_ENTRIES
199/*
200 * A simplified version of sysctl_debug_ktr_entries.
201 * No need to care about SMP, scheduling, etc.
202 */
203static void
204ktr_entries_initializer(void *dummy __unused)
205{
206	int mask;
207
208	/* Temporarily disable ktr in case malloc() is being traced. */
209	mask = ktr_mask;
210	ktr_mask = 0;
211	ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
212	    M_WAITOK | M_ZERO);
213	memcpy(ktr_buf, ktr_buf_init + ktr_idx,
214	    (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
215	if (ktr_idx != 0)
216		memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
217		    ktr_idx * sizeof(*ktr_buf));
218	ktr_entries = KTR_ENTRIES;
219	ktr_mask = mask;
220}
221SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
222    ktr_entries_initializer, NULL);
223#endif
224
225static int
226sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
227{
228	int entries, error, mask;
229	struct ktr_entry *buf, *oldbuf;
230
231	entries = ktr_entries;
232	error = sysctl_handle_int(oidp, &entries, 0, req);
233	if (error || !req->newptr)
234		return (error);
235	if (entries > KTR_ENTRIES_MAX)
236		return (ERANGE);
237	/* Disable ktr temporarily. */
238	mask = ktr_mask;
239	atomic_store_rel_int(&ktr_mask, 0);
240	/* Wait for threads to go idle. */
241	if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
242		ktr_mask = mask;
243		return (error);
244	}
245	if (ktr_buf != ktr_buf_init)
246		oldbuf = ktr_buf;
247	else
248		oldbuf = NULL;
249	/* Allocate a new buffer. */
250	buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
251	/* Install the new buffer and restart ktr. */
252	ktr_buf = buf;
253	ktr_entries = entries;
254	ktr_idx = 0;
255	atomic_store_rel_int(&ktr_mask, mask);
256	if (oldbuf != NULL)
257		free(oldbuf, M_KTR);
258
259	return (error);
260}
261
262SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
263    sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
264
265#ifdef KTR_VERBOSE
266int	ktr_verbose = KTR_VERBOSE;
267TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
268SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
269#endif
270
271#ifdef KTR_ALQ
272struct alq *ktr_alq;
273char	ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
274int	ktr_alq_cnt = 0;
275int	ktr_alq_depth = KTR_ENTRIES;
276int	ktr_alq_enabled = 0;
277int	ktr_alq_failed = 0;
278int	ktr_alq_max = 0;
279
280SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
281    "Maximum number of entries to write");
282SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
283    "Current number of written entries");
284SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
285    "Number of times we overran the buffer");
286SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
287    "Number of items in the write buffer");
288SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
289    sizeof(ktr_alq_file), "KTR logging file");
290
291static int
292sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
293{
294	int error;
295	int enable;
296
297	enable = ktr_alq_enabled;
298
299	error = sysctl_handle_int(oidp, &enable, 0, req);
300	if (error || !req->newptr)
301		return (error);
302
303	if (enable) {
304		if (ktr_alq_enabled)
305			return (0);
306		error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
307		    req->td->td_ucred, ALQ_DEFAULT_CMODE,
308		    sizeof(struct ktr_entry), ktr_alq_depth);
309		if (error == 0) {
310			ktr_alq_cnt = 0;
311			ktr_alq_failed = 0;
312			ktr_alq_enabled = 1;
313		}
314	} else {
315		if (ktr_alq_enabled == 0)
316			return (0);
317		ktr_alq_enabled = 0;
318		alq_close(ktr_alq);
319		ktr_alq = NULL;
320	}
321
322	return (error);
323}
324SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
325    CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
326    "I", "Enable KTR logging");
327#endif
328
329void
330ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
331    u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
332    u_long arg6)
333{
334	struct ktr_entry *entry;
335#ifdef KTR_ALQ
336	struct ale *ale = NULL;
337#endif
338	int newindex, saveindex;
339#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
340	struct thread *td;
341#endif
342	int cpu;
343
344	if (panicstr)
345		return;
346	if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
347		return;
348	cpu = KTR_CPU;
349	if (!CPU_ISSET(cpu, &ktr_cpumask))
350		return;
351#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
352	td = curthread;
353	if (td->td_pflags & TDP_INKTR)
354		return;
355	td->td_pflags |= TDP_INKTR;
356#endif
357#ifdef KTR_ALQ
358	if (ktr_alq_enabled) {
359		if (td->td_critnest == 0 &&
360		    (td->td_flags & TDF_IDLETD) == 0 &&
361		    td != ald_thread) {
362			if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
363				goto done;
364			if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
365				ktr_alq_failed++;
366				goto done;
367			}
368			ktr_alq_cnt++;
369			entry = (struct ktr_entry *)ale->ae_data;
370		} else {
371			goto done;
372		}
373	} else
374#endif
375	{
376		do {
377			saveindex = ktr_idx;
378			newindex = (saveindex + 1) % ktr_entries;
379		} while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
380		entry = &ktr_buf[saveindex];
381	}
382	entry->ktr_timestamp = KTR_TIME;
383	entry->ktr_cpu = cpu;
384	entry->ktr_thread = curthread;
385	if (file != NULL)
386		while (strncmp(file, "../", 3) == 0)
387			file += 3;
388	entry->ktr_file = file;
389	entry->ktr_line = line;
390#ifdef KTR_VERBOSE
391	if (ktr_verbose) {
392#ifdef SMP
393		printf("cpu%d ", cpu);
394#endif
395		if (ktr_verbose > 1) {
396			printf("%s.%d\t", entry->ktr_file,
397			    entry->ktr_line);
398		}
399		printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
400		printf("\n");
401	}
402#endif
403	entry->ktr_desc = format;
404	entry->ktr_parms[0] = arg1;
405	entry->ktr_parms[1] = arg2;
406	entry->ktr_parms[2] = arg3;
407	entry->ktr_parms[3] = arg4;
408	entry->ktr_parms[4] = arg5;
409	entry->ktr_parms[5] = arg6;
410#ifdef KTR_ALQ
411	if (ktr_alq_enabled && ale)
412		alq_post(ktr_alq, ale);
413done:
414#endif
415#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
416	td->td_pflags &= ~TDP_INKTR;
417#endif
418}
419
420#ifdef DDB
421
422struct tstate {
423	int	cur;
424	int	first;
425};
426static	struct tstate tstate;
427static	int db_ktr_verbose;
428static	int db_mach_vtrace(void);
429
430DB_SHOW_COMMAND(ktr, db_ktr_all)
431{
432
433	tstate.cur = (ktr_idx - 1) % ktr_entries;
434	tstate.first = -1;
435	db_ktr_verbose = 0;
436	db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
437	db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
438	if (strchr(modif, 'a') != NULL) {
439		db_disable_pager();
440		while (cncheckc() != -1)
441			if (db_mach_vtrace() == 0)
442				break;
443	} else {
444		while (!db_pager_quit)
445			if (db_mach_vtrace() == 0)
446				break;
447	}
448}
449
450static int
451db_mach_vtrace(void)
452{
453	struct ktr_entry	*kp;
454
455	if (tstate.cur == tstate.first || ktr_buf == NULL) {
456		db_printf("--- End of trace buffer ---\n");
457		return (0);
458	}
459	kp = &ktr_buf[tstate.cur];
460
461	/* Skip over unused entries. */
462	if (kp->ktr_desc == NULL) {
463		db_printf("--- End of trace buffer ---\n");
464		return (0);
465	}
466	db_printf("%d (%p", tstate.cur, kp->ktr_thread);
467#ifdef SMP
468	db_printf(":cpu%d", kp->ktr_cpu);
469#endif
470	db_printf(")");
471	if (db_ktr_verbose >= 1) {
472		db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
473	}
474	if (db_ktr_verbose >= 2) {
475		db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
476	}
477	db_printf(": ");
478	db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
479	    kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
480	    kp->ktr_parms[5]);
481	db_printf("\n");
482
483	if (tstate.first == -1)
484		tstate.first = tstate.cur;
485
486	if (--tstate.cur < 0)
487		tstate.cur = ktr_entries - 1;
488
489	return (1);
490}
491
492#endif	/* DDB */
493