kern_ktr.c revision 243971 
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 243971 2012-12-07 05:55:48Z alfred $");
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/queue.h>
44#include <sys/alq.h>
45#include <sys/cons.h>
46#include <sys/cpuset.h>
47#include <sys/kernel.h>
48#include <sys/ktr.h>
49#include <sys/libkern.h>
50#include <sys/lock.h>
51#include <sys/malloc.h>
52#include <sys/mutex.h>
53#include <sys/proc.h>
54#include <sys/smp.h>
55#include <sys/sysctl.h>
56#include <sys/systm.h>
57#include <sys/time.h>
58
59#include <machine/cpu.h>
60#ifdef __sparc64__
61#include <machine/ktr.h>
62#endif
63
64#ifdef DDB
65#include <ddb/ddb.h>
66#include <ddb/db_output.h>
67#endif
68
69#ifndef KTR_ENTRIES
70#define	KTR_ENTRIES	1024
71#endif
72
73/* Limit the allocations to something manageable. */
74#define	KTR_ENTRIES_MAX	(8 * 1024 * 1024)
75
76#ifndef KTR_MASK
77#define	KTR_MASK	(0)
78#endif
79
80#ifndef KTR_CPUMASK
81#define	KTR_CPUMASK	CPUSET_FSET
82#endif
83
84#ifndef KTR_TIME
85#define	KTR_TIME	get_cyclecount()
86#endif
87
88#ifndef KTR_CPU
89#define	KTR_CPU		PCPU_GET(cpuid)
90#endif
91
92static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
93
94FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
95
96volatile int	ktr_idx = 0;
97int	ktr_mask = KTR_MASK;
98int	ktr_compile = KTR_COMPILE;
99int	ktr_entries = KTR_ENTRIES;
100int	ktr_version = KTR_VERSION;
101struct	ktr_entry ktr_buf_init[KTR_ENTRIES];
102struct	ktr_entry *ktr_buf = ktr_buf_init;
103cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
104static char ktr_cpumask_str[CPUSETBUFSIZ];
105
106TUNABLE_INT("debug.ktr.mask", &ktr_mask);
107
108TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
109
110static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
111
112SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
113    &ktr_version, 0, "Version of the KTR interface");
114
115SYSCTL_UINT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
116    &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
117
118static void
119ktr_cpumask_initializer(void *dummy __unused)
120{
121
122	/*
123	 * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
124	 * already set, if necessary.
125	 */
126	if (ktr_cpumask_str[0] != '\0' &&
127	    cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
128		CPU_FILL(&ktr_cpumask);
129}
130SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
131    ktr_cpumask_initializer, NULL);
132
133static int
134sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
135{
136	char lktr_cpumask_str[CPUSETBUFSIZ];
137	cpuset_t imask;
138	int error;
139
140	cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
141	error = sysctl_handle_string(oidp, lktr_cpumask_str,
142	    sizeof(lktr_cpumask_str), req);
143	if (error != 0 || req->newptr == NULL)
144		return (error);
145	if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
146		return (EINVAL);
147	CPU_COPY(&imask, &ktr_cpumask);
148
149	return (error);
150}
151SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
152    CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
153    sysctl_debug_ktr_cpumask, "S",
154    "Bitmask of CPUs on which KTR logging is enabled");
155
156static int
157sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
158{
159	int clear, error;
160
161	clear = 0;
162	error = sysctl_handle_int(oidp, &clear, 0, req);
163	if (error || !req->newptr)
164		return (error);
165
166	if (clear) {
167		bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
168		ktr_idx = 0;
169	}
170
171	return (error);
172}
173SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
174    sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
175
176/*
177 * This is a sysctl proc so that it is serialized as !MPSAFE along with
178 * the other ktr sysctl procs.
179 */
180static int
181sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
182{
183	int mask, error;
184
185	mask = ktr_mask;
186	error = sysctl_handle_int(oidp, &mask, 0, req);
187	if (error || !req->newptr)
188		return (error);
189	ktr_mask = mask;
190	return (error);
191}
192
193SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_UINT|CTLFLAG_RW, 0, 0,
194    sysctl_debug_ktr_mask, "IU",
195    "Bitmask of KTR event classes for which logging is enabled");
196
197static int
198sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
199{
200	int entries, error, mask;
201	struct ktr_entry *buf, *oldbuf;
202
203	entries = ktr_entries;
204	error = sysctl_handle_int(oidp, &entries, 0, req);
205	if (error || !req->newptr)
206		return (error);
207	if (entries > KTR_ENTRIES_MAX)
208		return (ERANGE);
209	/* Disable ktr temporarily. */
210	mask = ktr_mask;
211	atomic_store_rel_int(&ktr_mask, 0);
212	/* Wait for threads to go idle. */
213	if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
214		ktr_mask = mask;
215		return (error);
216	}
217	if (ktr_buf != ktr_buf_init)
218		oldbuf = ktr_buf;
219	else
220		oldbuf = NULL;
221	/* Allocate a new buffer. */
222	buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
223	/* Install the new buffer and restart ktr. */
224	ktr_buf = buf;
225	ktr_entries = entries;
226	ktr_idx = 0;
227	atomic_store_rel_int(&ktr_mask, mask);
228	if (oldbuf != NULL)
229		free(oldbuf, M_KTR);
230
231	return (error);
232}
233
234SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
235    sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
236
237#ifdef KTR_VERBOSE
238int	ktr_verbose = KTR_VERBOSE;
239TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
240SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
241#endif
242
243#ifdef KTR_ALQ
244struct alq *ktr_alq;
245char	ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
246int	ktr_alq_cnt = 0;
247int	ktr_alq_depth = KTR_ENTRIES;
248int	ktr_alq_enabled = 0;
249int	ktr_alq_failed = 0;
250int	ktr_alq_max = 0;
251
252SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
253    "Maximum number of entries to write");
254SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
255    "Current number of written entries");
256SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
257    "Number of times we overran the buffer");
258SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
259    "Number of items in the write buffer");
260SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
261    sizeof(ktr_alq_file), "KTR logging file");
262
263static int
264sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
265{
266	int error;
267	int enable;
268
269	enable = ktr_alq_enabled;
270
271	error = sysctl_handle_int(oidp, &enable, 0, req);
272	if (error || !req->newptr)
273		return (error);
274
275	if (enable) {
276		if (ktr_alq_enabled)
277			return (0);
278		error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
279		    req->td->td_ucred, ALQ_DEFAULT_CMODE,
280		    sizeof(struct ktr_entry), ktr_alq_depth);
281		if (error == 0) {
282			ktr_alq_cnt = 0;
283			ktr_alq_failed = 0;
284			ktr_alq_enabled = 1;
285		}
286	} else {
287		if (ktr_alq_enabled == 0)
288			return (0);
289		ktr_alq_enabled = 0;
290		alq_close(ktr_alq);
291		ktr_alq = NULL;
292	}
293
294	return (error);
295}
296SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
297    CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
298    "I", "Enable KTR logging");
299#endif
300
301void
302ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
303    u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
304    u_long arg6)
305{
306	struct ktr_entry *entry;
307#ifdef KTR_ALQ
308	struct ale *ale = NULL;
309#endif
310	int newindex, saveindex;
311#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
312	struct thread *td;
313#endif
314	int cpu;
315
316	if (panicstr)
317		return;
318	if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
319		return;
320	cpu = KTR_CPU;
321	if (!CPU_ISSET(cpu, &ktr_cpumask))
322		return;
323#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
324	td = curthread;
325	if (td->td_pflags & TDP_INKTR)
326		return;
327	td->td_pflags |= TDP_INKTR;
328#endif
329#ifdef KTR_ALQ
330	if (ktr_alq_enabled) {
331		if (td->td_critnest == 0 &&
332		    (td->td_flags & TDF_IDLETD) == 0 &&
333		    td != ald_thread) {
334			if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
335				goto done;
336			if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
337				ktr_alq_failed++;
338				goto done;
339			}
340			ktr_alq_cnt++;
341			entry = (struct ktr_entry *)ale->ae_data;
342		} else {
343			goto done;
344		}
345	} else
346#endif
347	{
348		do {
349			saveindex = ktr_idx;
350			newindex = (saveindex + 1) % ktr_entries;
351		} while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
352		entry = &ktr_buf[saveindex];
353	}
354	entry->ktr_timestamp = KTR_TIME;
355	entry->ktr_cpu = cpu;
356	entry->ktr_thread = curthread;
357	if (file != NULL)
358		while (strncmp(file, "../", 3) == 0)
359			file += 3;
360	entry->ktr_file = file;
361	entry->ktr_line = line;
362#ifdef KTR_VERBOSE
363	if (ktr_verbose) {
364#ifdef SMP
365		printf("cpu%d ", cpu);
366#endif
367		if (ktr_verbose > 1) {
368			printf("%s.%d\t", entry->ktr_file,
369			    entry->ktr_line);
370		}
371		printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
372		printf("\n");
373	}
374#endif
375	entry->ktr_desc = format;
376	entry->ktr_parms[0] = arg1;
377	entry->ktr_parms[1] = arg2;
378	entry->ktr_parms[2] = arg3;
379	entry->ktr_parms[3] = arg4;
380	entry->ktr_parms[4] = arg5;
381	entry->ktr_parms[5] = arg6;
382#ifdef KTR_ALQ
383	if (ktr_alq_enabled && ale)
384		alq_post(ktr_alq, ale);
385done:
386#endif
387#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
388	td->td_pflags &= ~TDP_INKTR;
389#endif
390}
391
392#ifdef DDB
393
394struct tstate {
395	int	cur;
396	int	first;
397};
398static	struct tstate tstate;
399static	int db_ktr_verbose;
400static	int db_mach_vtrace(void);
401
402DB_SHOW_COMMAND(ktr, db_ktr_all)
403{
404
405	tstate.cur = (ktr_idx - 1) % ktr_entries;
406	tstate.first = -1;
407	db_ktr_verbose = 0;
408	db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
409	db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
410	if (strchr(modif, 'a') != NULL) {
411		db_disable_pager();
412		while (cncheckc() != -1)
413			if (db_mach_vtrace() == 0)
414				break;
415	} else {
416		while (!db_pager_quit)
417			if (db_mach_vtrace() == 0)
418				break;
419	}
420}
421
422static int
423db_mach_vtrace(void)
424{
425	struct ktr_entry	*kp;
426
427	if (tstate.cur == tstate.first || ktr_buf == NULL) {
428		db_printf("--- End of trace buffer ---\n");
429		return (0);
430	}
431	kp = &ktr_buf[tstate.cur];
432
433	/* Skip over unused entries. */
434	if (kp->ktr_desc == NULL) {
435		db_printf("--- End of trace buffer ---\n");
436		return (0);
437	}
438	db_printf("%d (%p", tstate.cur, kp->ktr_thread);
439#ifdef SMP
440	db_printf(":cpu%d", kp->ktr_cpu);
441#endif
442	db_printf(")");
443	if (db_ktr_verbose >= 1) {
444		db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
445	}
446	if (db_ktr_verbose >= 2) {
447		db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
448	}
449	db_printf(": ");
450	db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
451	    kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
452	    kp->ktr_parms[5]);
453	db_printf("\n");
454
455	if (tstate.first == -1)
456		tstate.first = tstate.cur;
457
458	if (--tstate.cur < 0)
459		tstate.cur = ktr_entries - 1;
460
461	return (1);
462}
463
464#endif	/* DDB */
465