xref: /freebsd/sys/kern/kern_ktr.c (revision b2db760808f74bb53c232900091c9da801ebbfcc)
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("$FreeBSD$");
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	(0)
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 
83 SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
84 
85 int	ktr_cpumask = KTR_CPUMASK;
86 TUNABLE_INT("debug.ktr.cpumask", &ktr_cpumask);
87 SYSCTL_INT(_debug_ktr, OID_AUTO, cpumask, CTLFLAG_RW,
88     &ktr_cpumask, 0, "Bitmask of CPUs on which KTR logging is enabled");
89 
90 int	ktr_mask = KTR_MASK;
91 TUNABLE_INT("debug.ktr.mask", &ktr_mask);
92 SYSCTL_INT(_debug_ktr, OID_AUTO, mask, CTLFLAG_RW,
93     &ktr_mask, 0, "Bitmask of KTR event classes for which logging is enabled");
94 
95 int	ktr_compile = KTR_COMPILE;
96 SYSCTL_INT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
97     &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
98 
99 int	ktr_entries = KTR_ENTRIES;
100 SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD,
101     &ktr_entries, 0, "Number of entries in the KTR buffer");
102 
103 int	ktr_version = KTR_VERSION;
104 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
105     &ktr_version, 0, "Version of the KTR interface");
106 
107 volatile int	ktr_idx = 0;
108 struct	ktr_entry ktr_buf[KTR_ENTRIES];
109 
110 static int
111 sysctl_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 }
127 SYSCTL_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
131 int	ktr_verbose = KTR_VERBOSE;
132 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
133 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
134 #endif
135 
136 #ifdef KTR_ALQ
137 struct alq *ktr_alq;
138 char	ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
139 int	ktr_alq_cnt = 0;
140 int	ktr_alq_depth = KTR_ENTRIES;
141 int	ktr_alq_enabled = 0;
142 int	ktr_alq_failed = 0;
143 int	ktr_alq_max = 0;
144 
145 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
146     "Maximum number of entries to write");
147 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
148     "Current number of written entries");
149 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
150     "Number of times we overran the buffer");
151 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
152     "Number of items in the write buffer");
153 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
154     sizeof(ktr_alq_file), "KTR logging file");
155 
156 static int
157 sysctl_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 }
189 SYSCTL_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 
194 void
195 ktr_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 #endif
203 	int newindex, saveindex;
204 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
205 	struct thread *td;
206 #endif
207 	int cpu;
208 
209 	if (panicstr)
210 		return;
211 	if ((ktr_mask & mask) == 0)
212 		return;
213 	cpu = KTR_CPU;
214 	if (((1 << cpu) & ktr_cpumask) == 0)
215 		return;
216 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
217 	td = curthread;
218 	if (td->td_pflags & TDP_INKTR)
219 		return;
220 	td->td_pflags |= TDP_INKTR;
221 #endif
222 #ifdef KTR_ALQ
223 	if (ktr_alq_enabled) {
224 		if (td->td_critnest == 0 &&
225 		    (td->td_flags & TDF_IDLETD) == 0 &&
226 		    td != ald_thread) {
227 			if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
228 				goto done;
229 			if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
230 				ktr_alq_failed++;
231 				goto done;
232 			}
233 			ktr_alq_cnt++;
234 			entry = (struct ktr_entry *)ale->ae_data;
235 		} else {
236 			goto done;
237 		}
238 	} else
239 #endif
240 	{
241 		do {
242 			saveindex = ktr_idx;
243 			newindex = (saveindex + 1) & (KTR_ENTRIES - 1);
244 		} while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
245 		entry = &ktr_buf[saveindex];
246 	}
247 	entry->ktr_timestamp = KTR_TIME;
248 	entry->ktr_cpu = cpu;
249 	entry->ktr_thread = curthread;
250 	if (file != NULL)
251 		while (strncmp(file, "../", 3) == 0)
252 			file += 3;
253 	entry->ktr_file = file;
254 	entry->ktr_line = line;
255 #ifdef KTR_VERBOSE
256 	if (ktr_verbose) {
257 #ifdef SMP
258 		printf("cpu%d ", cpu);
259 #endif
260 		if (ktr_verbose > 1) {
261 			printf("%s.%d\t", entry->ktr_file,
262 			    entry->ktr_line);
263 		}
264 		printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
265 		printf("\n");
266 	}
267 #endif
268 	entry->ktr_desc = format;
269 	entry->ktr_parms[0] = arg1;
270 	entry->ktr_parms[1] = arg2;
271 	entry->ktr_parms[2] = arg3;
272 	entry->ktr_parms[3] = arg4;
273 	entry->ktr_parms[4] = arg5;
274 	entry->ktr_parms[5] = arg6;
275 #ifdef KTR_ALQ
276 	if (ktr_alq_enabled && ale)
277 		alq_post(ktr_alq, ale);
278 done:
279 #endif
280 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
281 	td->td_pflags &= ~TDP_INKTR;
282 #endif
283 }
284 
285 #ifdef DDB
286 
287 struct tstate {
288 	int	cur;
289 	int	first;
290 };
291 static	struct tstate tstate;
292 static	int db_ktr_verbose;
293 static	int db_mach_vtrace(void);
294 
295 DB_SHOW_COMMAND(ktr, db_ktr_all)
296 {
297 
298 	tstate.cur = (ktr_idx - 1) & (KTR_ENTRIES - 1);
299 	tstate.first = -1;
300 	db_ktr_verbose = 0;
301 	db_ktr_verbose |= (index(modif, 'v') != NULL) ? 2 : 0;
302 	db_ktr_verbose |= (index(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
303 	if (index(modif, 'a') != NULL) {
304 		db_disable_pager();
305 		while (cncheckc() != -1)
306 			if (db_mach_vtrace() == 0)
307 				break;
308 	} else {
309 		while (!db_pager_quit)
310 			if (db_mach_vtrace() == 0)
311 				break;
312 	}
313 }
314 
315 static int
316 db_mach_vtrace(void)
317 {
318 	struct ktr_entry	*kp;
319 
320 	if (tstate.cur == tstate.first) {
321 		db_printf("--- End of trace buffer ---\n");
322 		return (0);
323 	}
324 	kp = &ktr_buf[tstate.cur];
325 
326 	/* Skip over unused entries. */
327 	if (kp->ktr_desc == NULL) {
328 		db_printf("--- End of trace buffer ---\n");
329 		return (0);
330 	}
331 	db_printf("%d (%p", tstate.cur, kp->ktr_thread);
332 #ifdef SMP
333 	db_printf(":cpu%d", kp->ktr_cpu);
334 #endif
335 	db_printf(")");
336 	if (db_ktr_verbose >= 1) {
337 		db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
338 	}
339 	if (db_ktr_verbose >= 2) {
340 		db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
341 	}
342 	db_printf(": ");
343 	db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
344 	    kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
345 	    kp->ktr_parms[5]);
346 	db_printf("\n");
347 
348 	if (tstate.first == -1)
349 		tstate.first = tstate.cur;
350 
351 	if (--tstate.cur < 0)
352 		tstate.cur = KTR_ENTRIES - 1;
353 
354 	return (1);
355 }
356 
357 #endif	/* DDB */
358