kern_ktr.c revision 205017 
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 * 3. Neither the name of the author nor the names of any co-contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30/*
31 * This module holds the global variables used by KTR and the ktr_tracepoint()
32 * function that does the actual tracing.
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: head/sys/kern/kern_ktr.c 205017 2010-03-11 15:13:55Z jhb $");
37
38#include "opt_ddb.h"
39#include "opt_ktr.h"
40#include "opt_alq.h"
41
42#include <sys/param.h>
43#include <sys/alq.h>
44#include <sys/cons.h>
45#include <sys/kernel.h>
46#include <sys/ktr.h>
47#include <sys/libkern.h>
48#include <sys/proc.h>
49#include <sys/sysctl.h>
50#include <sys/systm.h>
51#include <sys/time.h>
52
53#include <machine/cpu.h>
54#ifdef __sparc64__
55#include <machine/ktr.h>
56#endif
57
58#ifdef DDB
59#include <ddb/ddb.h>
60#include <ddb/db_output.h>
61#endif
62
63#ifndef KTR_ENTRIES
64#define	KTR_ENTRIES	1024
65#endif
66
67#ifndef KTR_MASK
68#define	KTR_MASK	(KTR_GEN)
69#endif
70
71#ifndef KTR_CPUMASK
72#define	KTR_CPUMASK	(~0)
73#endif
74
75#ifndef KTR_TIME
76#define	KTR_TIME	get_cyclecount()
77#endif
78
79#ifndef KTR_CPU
80#define	KTR_CPU		PCPU_GET(cpuid)
81#endif
82
83SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
84
85int	ktr_cpumask = KTR_CPUMASK;
86TUNABLE_INT("debug.ktr.cpumask", &ktr_cpumask);
87SYSCTL_INT(_debug_ktr, OID_AUTO, cpumask, CTLFLAG_RW,
88    &ktr_cpumask, 0, "Bitmask of CPUs on which KTR logging is enabled");
89
90int	ktr_mask = KTR_MASK;
91TUNABLE_INT("debug.ktr.mask", &ktr_mask);
92SYSCTL_INT(_debug_ktr, OID_AUTO, mask, CTLFLAG_RW,
93    &ktr_mask, 0, "Bitmask of KTR event classes for which logging is enabled");
94
95int	ktr_compile = KTR_COMPILE;
96SYSCTL_INT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
97    &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
98
99int	ktr_entries = KTR_ENTRIES;
100SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD,
101    &ktr_entries, 0, "Number of entries in the KTR buffer");
102
103int	ktr_version = KTR_VERSION;
104SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
105    &ktr_version, 0, "Version of the KTR interface");
106
107volatile int	ktr_idx = 0;
108struct	ktr_entry ktr_buf[KTR_ENTRIES];
109
110static int
111sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
112{
113	int clear, error;
114
115	clear = 0;
116	error = sysctl_handle_int(oidp, &clear, 0, req);
117	if (error || !req->newptr)
118		return (error);
119
120	if (clear) {
121		bzero(ktr_buf, sizeof(ktr_buf));
122		ktr_idx = 0;
123	}
124
125	return (error);
126}
127SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
128    sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
129
130#ifdef KTR_VERBOSE
131int	ktr_verbose = KTR_VERBOSE;
132TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
133SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
134#endif
135
136#ifdef KTR_ALQ
137struct alq *ktr_alq;
138char	ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
139int	ktr_alq_cnt = 0;
140int	ktr_alq_depth = KTR_ENTRIES;
141int	ktr_alq_enabled = 0;
142int	ktr_alq_failed = 0;
143int	ktr_alq_max = 0;
144
145SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
146    "Maximum number of entries to write");
147SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
148    "Current number of written entries");
149SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
150    "Number of times we overran the buffer");
151SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
152    "Number of items in the write buffer");
153SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
154    sizeof(ktr_alq_file), "KTR logging file");
155
156static int
157sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
158{
159	int error;
160	int enable;
161
162	enable = ktr_alq_enabled;
163
164	error = sysctl_handle_int(oidp, &enable, 0, req);
165	if (error || !req->newptr)
166		return (error);
167
168	if (enable) {
169		if (ktr_alq_enabled)
170			return (0);
171		error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
172		    req->td->td_ucred, ALQ_DEFAULT_CMODE,
173		    sizeof(struct ktr_entry), ktr_alq_depth);
174		if (error == 0) {
175			ktr_alq_cnt = 0;
176			ktr_alq_failed = 0;
177			ktr_alq_enabled = 1;
178		}
179	} else {
180		if (ktr_alq_enabled == 0)
181			return (0);
182		ktr_alq_enabled = 0;
183		alq_close(ktr_alq);
184		ktr_alq = NULL;
185	}
186
187	return (error);
188}
189SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
190    CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
191    "I", "Enable KTR logging");
192#endif
193
194void
195ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
196    u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
197    u_long arg6)
198{
199	struct ktr_entry *entry;
200#ifdef KTR_ALQ
201	struct ale *ale = NULL;
202#else
203	int newindex, saveindex;
204#endif
205#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
206	struct thread *td;
207#endif
208	int cpu;
209
210	if (panicstr)
211		return;
212	if ((ktr_mask & mask) == 0)
213		return;
214	cpu = KTR_CPU;
215	if (((1 << cpu) & ktr_cpumask) == 0)
216		return;
217#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
218	td = curthread;
219	if (td->td_pflags & TDP_INKTR)
220		return;
221	td->td_pflags |= TDP_INKTR;
222#endif
223#ifdef KTR_ALQ
224	if (ktr_alq_enabled &&
225	    td->td_critnest == 0 &&
226	    (td->td_flags & TDF_IDLETD) == 0 &&
227	    td != ald_thread) {
228		if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
229			goto done;
230		if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
231			ktr_alq_failed++;
232			goto done;
233		}
234		ktr_alq_cnt++;
235		entry = (struct ktr_entry *)ale->ae_data;
236	} else
237		goto done;
238#else
239	do {
240		saveindex = ktr_idx;
241		newindex = (saveindex + 1) & (KTR_ENTRIES - 1);
242	} while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
243	entry = &ktr_buf[saveindex];
244#endif
245	entry->ktr_timestamp = KTR_TIME;
246	entry->ktr_cpu = cpu;
247	entry->ktr_thread = curthread;
248	if (file != NULL)
249		while (strncmp(file, "../", 3) == 0)
250			file += 3;
251	entry->ktr_file = file;
252	entry->ktr_line = line;
253#ifdef KTR_VERBOSE
254	if (ktr_verbose) {
255#ifdef SMP
256		printf("cpu%d ", cpu);
257#endif
258		if (ktr_verbose > 1) {
259			printf("%s.%d\t", entry->ktr_file,
260			    entry->ktr_line);
261		}
262		printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
263		printf("\n");
264	}
265#endif
266	entry->ktr_desc = format;
267	entry->ktr_parms[0] = arg1;
268	entry->ktr_parms[1] = arg2;
269	entry->ktr_parms[2] = arg3;
270	entry->ktr_parms[3] = arg4;
271	entry->ktr_parms[4] = arg5;
272	entry->ktr_parms[5] = arg6;
273#ifdef KTR_ALQ
274	if (ale)
275		alq_post(ktr_alq, ale);
276done:
277#endif
278#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
279	td->td_pflags &= ~TDP_INKTR;
280#endif
281}
282
283#ifdef DDB
284
285struct tstate {
286	int	cur;
287	int	first;
288};
289static	struct tstate tstate;
290static	int db_ktr_verbose;
291static	int db_mach_vtrace(void);
292
293DB_SHOW_COMMAND(ktr, db_ktr_all)
294{
295
296	tstate.cur = (ktr_idx - 1) & (KTR_ENTRIES - 1);
297	tstate.first = -1;
298	db_ktr_verbose = index(modif, 'v') != NULL;
299	if (index(modif, 'a') != NULL) {
300		db_disable_pager();
301		while (cncheckc() != -1)
302			if (db_mach_vtrace() == 0)
303				break;
304	} else {
305		while (!db_pager_quit)
306			if (db_mach_vtrace() == 0)
307				break;
308	}
309}
310
311static int
312db_mach_vtrace(void)
313{
314	struct ktr_entry	*kp;
315
316	if (tstate.cur == tstate.first) {
317		db_printf("--- End of trace buffer ---\n");
318		return (0);
319	}
320	kp = &ktr_buf[tstate.cur];
321
322	/* Skip over unused entries. */
323	if (kp->ktr_desc == NULL) {
324		db_printf("--- End of trace buffer ---\n");
325		return (0);
326	}
327	db_printf("%d (%p", tstate.cur, kp->ktr_thread);
328#ifdef SMP
329	db_printf(":cpu%d", kp->ktr_cpu);
330#endif
331	db_printf(")");
332	if (db_ktr_verbose) {
333		db_printf(" %10.10lld %s.%d", (long long)kp->ktr_timestamp,
334		    kp->ktr_file, kp->ktr_line);
335	}
336	db_printf(": ");
337	db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
338	    kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
339	    kp->ktr_parms[5]);
340	db_printf("\n");
341
342	if (tstate.first == -1)
343		tstate.first = tstate.cur;
344
345	if (--tstate.cur < 0)
346		tstate.cur = KTR_ENTRIES - 1;
347
348	return (1);
349}
350
351#endif	/* DDB */
352