1/*
2 * Copyright (c) 2000
3 * John Baldwin <jhb@FreeBSD.org>. 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 * 4. 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 JOHN BALDWIN 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 JOHN BALDWIN OR THE VOICES IN HIS HEAD
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
27 * THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: head/sys/kern/kern_ktr.c 111270 2003-02-22 23:30:37Z jake $
30 */
31
32/*
33 * This module holds the global variables used by KTR and the ktr_tracepoint()
34 * function that does the actual tracing.
35 */
36
37#include "opt_ddb.h"
38#include "opt_ktr.h"
39#include "opt_alq.h"
40
41#include <sys/param.h>
42#include <sys/alq.h>
43#include <sys/cons.h>
44#include <sys/kernel.h>
45#include <sys/ktr.h>
46#include <sys/libkern.h>
47#include <sys/proc.h>
48#include <sys/sysctl.h>
49#include <sys/systm.h>
50#include <sys/time.h>
51
52#include <machine/cpu.h>
53#ifdef __sparc64__
54#include <machine/ktr.h>
55#endif
56
57
58#include <ddb/ddb.h>
59
60#ifndef KTR_ENTRIES
61#define KTR_ENTRIES 1024
62#endif
63
64#ifndef KTR_MASK
65#define KTR_MASK (KTR_GEN)
66#endif
67
68#ifndef KTR_CPUMASK
69#define KTR_CPUMASK (~0)
70#endif
71
72#ifndef KTR_TIME
73#define KTR_TIME get_cyclecount()
74#endif
75
76#ifndef KTR_CPU
77#define KTR_CPU PCPU_GET(cpuid)
78#endif
79
80SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
81
82int ktr_cpumask = KTR_CPUMASK;
83TUNABLE_INT("debug.ktr.cpumask", &ktr_cpumask);
84SYSCTL_INT(_debug_ktr, OID_AUTO, cpumask, CTLFLAG_RW, &ktr_cpumask, 0, "");
85
86int ktr_mask = KTR_MASK;
87TUNABLE_INT("debug.ktr.mask", &ktr_mask);
88SYSCTL_INT(_debug_ktr, OID_AUTO, mask, CTLFLAG_RW, &ktr_mask, 0, "");
89
90int ktr_entries = KTR_ENTRIES;
91SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD, &ktr_entries, 0, "");
92
93int ktr_version = KTR_VERSION;
94SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD, &ktr_version, 0, "");
95
96volatile int ktr_idx = 0;
97struct ktr_entry ktr_buf[KTR_ENTRIES];
98
99#ifdef KTR_VERBOSE
100int ktr_verbose = KTR_VERBOSE;
101TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
102SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
103#endif
104
105#ifdef KTR_ALQ
106struct alq *ktr_alq;
107char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
108int ktr_alq_cnt = 0;
109int ktr_alq_depth = KTR_ENTRIES;
110int ktr_alq_enabled = 0;
111int ktr_alq_failed = 0;
112int ktr_alq_max = 0;
113
114SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
115 "Maximum number of entries to write");
116SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
117 "Current number of written entries");
118SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
119 "Number of times we overran the buffer");
120SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
121 "Number of items in the write buffer");
122SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
123 sizeof(ktr_alq_file), "KTR logging file");
124
125static int
126sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
127{
128 int error;
129 int enable;
130
131 enable = ktr_alq_enabled;
132
133 error = sysctl_handle_int(oidp, &enable, 0, req);
134 if (error || !req->newptr)
135 return (error);
136
137 if (enable) {
138 if (ktr_alq_enabled)
139 return (0);
140 error = suser(curthread);
141 if (error)
142 return (error);
143 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
144 sizeof(struct ktr_entry), ktr_alq_depth);
145 if (error == 0) {
146 ktr_mask &= ~KTR_ALQ_MASK;
147 ktr_alq_cnt = 0;
148 ktr_alq_failed = 0;
149 ktr_alq_enabled = 1;
150 }
151 } else {
152 if (ktr_alq_enabled == 0)
153 return (0);
154 ktr_alq_enabled = 0;
155 alq_close(ktr_alq);
156 ktr_alq = NULL;
157 }
158
159 return (error);
160}
161SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
162 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
163 "I", "Enable KTR logging");
164#endif
165
166void
167ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
168 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
169 u_long arg6)
170{
171 struct ktr_entry *entry;
172#ifdef KTR_ALQ
173 struct ale *ale = NULL;
174#else
175 int newindex, saveindex;
176#endif
177#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
178 struct thread *td;
179#endif
180 int cpu;
181
182 if (panicstr)
183 return;
184 if ((ktr_mask & mask) == 0)
185 return;
186 cpu = KTR_CPU;
187 if (((1 << cpu) & ktr_cpumask) == 0)
188 return;
189#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
190 td = curthread;
191 if (td->td_inktr)
192 return;
193 td->td_inktr++;
194#endif
195#ifdef KTR_ALQ
196 if (ktr_alq_enabled &&
197 td->td_critnest == 0 &&
198 (td->td_kse->ke_flags & KEF_IDLEKSE) == 0 &&
199 td != ald_thread) {
200 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
201 goto done;
202 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
203 ktr_alq_failed++;
204 goto done;
205 }
206 ktr_alq_cnt++;
207 entry = (struct ktr_entry *)ale->ae_data;
208 } else
209 goto done;
210#else
211 do {
212 saveindex = ktr_idx;
213 newindex = (saveindex + 1) & (KTR_ENTRIES - 1);
214 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
215 entry = &ktr_buf[saveindex];
216#endif
217 entry->ktr_timestamp = KTR_TIME;
218 entry->ktr_cpu = cpu;
219 entry->ktr_file = file;
220 entry->ktr_line = line;
221#ifdef KTR_VERBOSE
222 if (ktr_verbose) {
223#ifdef SMP
224 printf("cpu%d ", cpu);
225#endif
226 if (ktr_verbose > 1) {
227 printf("%s.%d\t", entry->ktr_file,
228 entry->ktr_line);
229 }
230 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
231 printf("\n");
232 }
233#endif
234 entry->ktr_desc = format;
235 entry->ktr_parms[0] = arg1;
236 entry->ktr_parms[1] = arg2;
237 entry->ktr_parms[2] = arg3;
238 entry->ktr_parms[3] = arg4;
239 entry->ktr_parms[4] = arg5;
240 entry->ktr_parms[5] = arg6;
241#ifdef KTR_ALQ
242 if (ale)
243 alq_post(ktr_alq, ale);
244done:
245#endif
246#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
247 td->td_inktr--;
248#endif
249}
250
251#ifdef DDB
252
253struct tstate {
254 int cur;
255 int first;
256};
257static struct tstate tstate;
258static int db_ktr_verbose;
259static int db_mach_vtrace(void);
260
261#define NUM_LINES_PER_PAGE 18
262
263DB_SHOW_COMMAND(ktr, db_ktr_all)
264{
265 int c, lines;
266 int all = 0;
267
268 lines = NUM_LINES_PER_PAGE;
269 tstate.cur = (ktr_idx - 1) & (KTR_ENTRIES - 1);
270 tstate.first = -1;
271 if (strcmp(modif, "v") == 0)
272 db_ktr_verbose = 1;
273 else
274 db_ktr_verbose = 0;
275 if (strcmp(modif, "a") == 0)
276 all = 1;
277 while (db_mach_vtrace())
278 if (all) {
279 if (cncheckc() != -1)
280 return;
281 } else if (--lines == 0) {
282 db_printf("--More--");
283 c = cngetc();
284 db_printf("\r");
285 switch (c) {
286 case '\n': /* one more line */
287 lines = 1;
288 break;
289 case ' ': /* one more page */
290 lines = NUM_LINES_PER_PAGE;
291 break;
292 default:
293 db_printf("\n");
294 return;
295 }
296 }
297}
298
299static int
300db_mach_vtrace(void)
301{
302 struct ktr_entry *kp;
303
304 if (tstate.cur == tstate.first) {
305 db_printf("--- End of trace buffer ---\n");
306 return (0);
307 }
308 kp = &ktr_buf[tstate.cur];
309
310 /* Skip over unused entries. */
311 if (kp->ktr_desc == NULL) {
312 db_printf("--- End of trace buffer ---\n");
313 return (0);
314 }
315 db_printf("%d: ", tstate.cur);
316#ifdef SMP
317 db_printf("cpu%d ", kp->ktr_cpu);
318#endif
319 if (db_ktr_verbose) {
320 db_printf("%10.10lld %s.%d\t", (long long)kp->ktr_timestamp,
321 kp->ktr_file, kp->ktr_line);
322 }
323 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
324 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
325 kp->ktr_parms[5]);
326 db_printf("\n");
327
328 if (tstate.first == -1)
329 tstate.first = tstate.cur;
330
331 if (--tstate.cur < 0)
332 tstate.cur = KTR_ENTRIES - 1;
333
334 return (1);
335}
336
337#endif /* DDB */
2 * Copyright (c) 2000
3 * John Baldwin <jhb@FreeBSD.org>. 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 * 4. 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 JOHN BALDWIN 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 JOHN BALDWIN OR THE VOICES IN HIS HEAD
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
27 * THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: head/sys/kern/kern_ktr.c 111270 2003-02-22 23:30:37Z jake $
30 */
31
32/*
33 * This module holds the global variables used by KTR and the ktr_tracepoint()
34 * function that does the actual tracing.
35 */
36
37#include "opt_ddb.h"
38#include "opt_ktr.h"
39#include "opt_alq.h"
40
41#include <sys/param.h>
42#include <sys/alq.h>
43#include <sys/cons.h>
44#include <sys/kernel.h>
45#include <sys/ktr.h>
46#include <sys/libkern.h>
47#include <sys/proc.h>
48#include <sys/sysctl.h>
49#include <sys/systm.h>
50#include <sys/time.h>
51
52#include <machine/cpu.h>
53#ifdef __sparc64__
54#include <machine/ktr.h>
55#endif
56
57
58#include <ddb/ddb.h>
59
60#ifndef KTR_ENTRIES
61#define KTR_ENTRIES 1024
62#endif
63
64#ifndef KTR_MASK
65#define KTR_MASK (KTR_GEN)
66#endif
67
68#ifndef KTR_CPUMASK
69#define KTR_CPUMASK (~0)
70#endif
71
72#ifndef KTR_TIME
73#define KTR_TIME get_cyclecount()
74#endif
75
76#ifndef KTR_CPU
77#define KTR_CPU PCPU_GET(cpuid)
78#endif
79
80SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
81
82int ktr_cpumask = KTR_CPUMASK;
83TUNABLE_INT("debug.ktr.cpumask", &ktr_cpumask);
84SYSCTL_INT(_debug_ktr, OID_AUTO, cpumask, CTLFLAG_RW, &ktr_cpumask, 0, "");
85
86int ktr_mask = KTR_MASK;
87TUNABLE_INT("debug.ktr.mask", &ktr_mask);
88SYSCTL_INT(_debug_ktr, OID_AUTO, mask, CTLFLAG_RW, &ktr_mask, 0, "");
89
90int ktr_entries = KTR_ENTRIES;
91SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD, &ktr_entries, 0, "");
92
93int ktr_version = KTR_VERSION;
94SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD, &ktr_version, 0, "");
95
96volatile int ktr_idx = 0;
97struct ktr_entry ktr_buf[KTR_ENTRIES];
98
99#ifdef KTR_VERBOSE
100int ktr_verbose = KTR_VERBOSE;
101TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
102SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
103#endif
104
105#ifdef KTR_ALQ
106struct alq *ktr_alq;
107char ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
108int ktr_alq_cnt = 0;
109int ktr_alq_depth = KTR_ENTRIES;
110int ktr_alq_enabled = 0;
111int ktr_alq_failed = 0;
112int ktr_alq_max = 0;
113
114SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
115 "Maximum number of entries to write");
116SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
117 "Current number of written entries");
118SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
119 "Number of times we overran the buffer");
120SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
121 "Number of items in the write buffer");
122SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
123 sizeof(ktr_alq_file), "KTR logging file");
124
125static int
126sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
127{
128 int error;
129 int enable;
130
131 enable = ktr_alq_enabled;
132
133 error = sysctl_handle_int(oidp, &enable, 0, req);
134 if (error || !req->newptr)
135 return (error);
136
137 if (enable) {
138 if (ktr_alq_enabled)
139 return (0);
140 error = suser(curthread);
141 if (error)
142 return (error);
143 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
144 sizeof(struct ktr_entry), ktr_alq_depth);
145 if (error == 0) {
146 ktr_mask &= ~KTR_ALQ_MASK;
147 ktr_alq_cnt = 0;
148 ktr_alq_failed = 0;
149 ktr_alq_enabled = 1;
150 }
151 } else {
152 if (ktr_alq_enabled == 0)
153 return (0);
154 ktr_alq_enabled = 0;
155 alq_close(ktr_alq);
156 ktr_alq = NULL;
157 }
158
159 return (error);
160}
161SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
162 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
163 "I", "Enable KTR logging");
164#endif
165
166void
167ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
168 u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
169 u_long arg6)
170{
171 struct ktr_entry *entry;
172#ifdef KTR_ALQ
173 struct ale *ale = NULL;
174#else
175 int newindex, saveindex;
176#endif
177#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
178 struct thread *td;
179#endif
180 int cpu;
181
182 if (panicstr)
183 return;
184 if ((ktr_mask & mask) == 0)
185 return;
186 cpu = KTR_CPU;
187 if (((1 << cpu) & ktr_cpumask) == 0)
188 return;
189#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
190 td = curthread;
191 if (td->td_inktr)
192 return;
193 td->td_inktr++;
194#endif
195#ifdef KTR_ALQ
196 if (ktr_alq_enabled &&
197 td->td_critnest == 0 &&
198 (td->td_kse->ke_flags & KEF_IDLEKSE) == 0 &&
199 td != ald_thread) {
200 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
201 goto done;
202 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
203 ktr_alq_failed++;
204 goto done;
205 }
206 ktr_alq_cnt++;
207 entry = (struct ktr_entry *)ale->ae_data;
208 } else
209 goto done;
210#else
211 do {
212 saveindex = ktr_idx;
213 newindex = (saveindex + 1) & (KTR_ENTRIES - 1);
214 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
215 entry = &ktr_buf[saveindex];
216#endif
217 entry->ktr_timestamp = KTR_TIME;
218 entry->ktr_cpu = cpu;
219 entry->ktr_file = file;
220 entry->ktr_line = line;
221#ifdef KTR_VERBOSE
222 if (ktr_verbose) {
223#ifdef SMP
224 printf("cpu%d ", cpu);
225#endif
226 if (ktr_verbose > 1) {
227 printf("%s.%d\t", entry->ktr_file,
228 entry->ktr_line);
229 }
230 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
231 printf("\n");
232 }
233#endif
234 entry->ktr_desc = format;
235 entry->ktr_parms[0] = arg1;
236 entry->ktr_parms[1] = arg2;
237 entry->ktr_parms[2] = arg3;
238 entry->ktr_parms[3] = arg4;
239 entry->ktr_parms[4] = arg5;
240 entry->ktr_parms[5] = arg6;
241#ifdef KTR_ALQ
242 if (ale)
243 alq_post(ktr_alq, ale);
244done:
245#endif
246#if defined(KTR_VERBOSE) || defined(KTR_ALQ)
247 td->td_inktr--;
248#endif
249}
250
251#ifdef DDB
252
253struct tstate {
254 int cur;
255 int first;
256};
257static struct tstate tstate;
258static int db_ktr_verbose;
259static int db_mach_vtrace(void);
260
261#define NUM_LINES_PER_PAGE 18
262
263DB_SHOW_COMMAND(ktr, db_ktr_all)
264{
265 int c, lines;
266 int all = 0;
267
268 lines = NUM_LINES_PER_PAGE;
269 tstate.cur = (ktr_idx - 1) & (KTR_ENTRIES - 1);
270 tstate.first = -1;
271 if (strcmp(modif, "v") == 0)
272 db_ktr_verbose = 1;
273 else
274 db_ktr_verbose = 0;
275 if (strcmp(modif, "a") == 0)
276 all = 1;
277 while (db_mach_vtrace())
278 if (all) {
279 if (cncheckc() != -1)
280 return;
281 } else if (--lines == 0) {
282 db_printf("--More--");
283 c = cngetc();
284 db_printf("\r");
285 switch (c) {
286 case '\n': /* one more line */
287 lines = 1;
288 break;
289 case ' ': /* one more page */
290 lines = NUM_LINES_PER_PAGE;
291 break;
292 default:
293 db_printf("\n");
294 return;
295 }
296 }
297}
298
299static int
300db_mach_vtrace(void)
301{
302 struct ktr_entry *kp;
303
304 if (tstate.cur == tstate.first) {
305 db_printf("--- End of trace buffer ---\n");
306 return (0);
307 }
308 kp = &ktr_buf[tstate.cur];
309
310 /* Skip over unused entries. */
311 if (kp->ktr_desc == NULL) {
312 db_printf("--- End of trace buffer ---\n");
313 return (0);
314 }
315 db_printf("%d: ", tstate.cur);
316#ifdef SMP
317 db_printf("cpu%d ", kp->ktr_cpu);
318#endif
319 if (db_ktr_verbose) {
320 db_printf("%10.10lld %s.%d\t", (long long)kp->ktr_timestamp,
321 kp->ktr_file, kp->ktr_line);
322 }
323 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
324 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
325 kp->ktr_parms[5]);
326 db_printf("\n");
327
328 if (tstate.first == -1)
329 tstate.first = tstate.cur;
330
331 if (--tstate.cur < 0)
332 tstate.cur = KTR_ENTRIES - 1;
333
334 return (1);
335}
336
337#endif /* DDB */