1246586Sdelphij/*- 2246586Sdelphij * SPDX-License-Identifier: BSD-2-Clause 3246586Sdelphij * 4246586Sdelphij * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org> 5246586Sdelphij * 6246586Sdelphij * Redistribution and use in source and binary forms, with or without 7246586Sdelphij * modification, are permitted provided that the following conditions 8246586Sdelphij * are met: 9246586Sdelphij * 1. Redistributions of source code must retain the above copyright 10246586Sdelphij * notice, this list of conditions and the following disclaimer. 11246586Sdelphij * 2. Redistributions in binary form must reproduce the above copyright 12246586Sdelphij * notice, this list of conditions and the following disclaimer in the 13246586Sdelphij * documentation and/or other materials provided with the distribution. 14246586Sdelphij * 15246586Sdelphij * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16246586Sdelphij * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17246586Sdelphij * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18246586Sdelphij * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19246586Sdelphij * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20246586Sdelphij * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21246586Sdelphij * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22246586Sdelphij * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23246586Sdelphij * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24246586Sdelphij * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25246586Sdelphij * SUCH DAMAGE. 26246586Sdelphij */ 27246586Sdelphij 28246586Sdelphij/* 29246586Sdelphij * This module holds the global variables used by KTR and the ktr_tracepoint() 30246586Sdelphij * function that does the actual tracing. 31246586Sdelphij */ 32246586Sdelphij 33246586Sdelphij#include <sys/cdefs.h> 34246586Sdelphij#include "opt_ddb.h" 35246586Sdelphij#include "opt_ktr.h" 36246586Sdelphij#include "opt_alq.h" 37301608Sngie 38301608Sngie#include <sys/param.h> 39246586Sdelphij#include <sys/queue.h> 40246586Sdelphij#include <sys/alq.h> 41246586Sdelphij#include <sys/cons.h> 42246586Sdelphij#include <sys/cpuset.h> 43246586Sdelphij#include <sys/kdb.h> 44246586Sdelphij#include <sys/kernel.h> 45246586Sdelphij#include <sys/ktr.h> 46246586Sdelphij#include <sys/libkern.h> 47246586Sdelphij#include <sys/lock.h> 48246586Sdelphij#include <sys/malloc.h> 49246586Sdelphij#include <sys/mutex.h> 50246586Sdelphij#include <sys/proc.h> 51246586Sdelphij#include <sys/smp.h> 52246586Sdelphij#include <sys/sysctl.h> 53246586Sdelphij#include <sys/systm.h> 54246586Sdelphij#include <sys/time.h> 55246586Sdelphij 56246586Sdelphij#include <machine/cpu.h> 57294718Ssmh 58246586Sdelphij#ifdef DDB 59246586Sdelphij#include <ddb/ddb.h> 60246586Sdelphij#include <ddb/db_output.h> 61246586Sdelphij#endif 62246586Sdelphij 63246586Sdelphij#ifndef KTR_BOOT_ENTRIES 64246586Sdelphij#define KTR_BOOT_ENTRIES 1024 65246586Sdelphij#endif 66246586Sdelphij 67246586Sdelphij#ifndef KTR_ENTRIES 68246586Sdelphij#define KTR_ENTRIES 1024 69246586Sdelphij#endif 70246586Sdelphij 71246586Sdelphij/* Limit the allocations to something manageable. */ 72246586Sdelphij#define KTR_ENTRIES_MAX (8 * 1024 * 1024) 73246586Sdelphij 74246586Sdelphij#ifndef KTR_MASK 75246586Sdelphij#define KTR_MASK (0) 76246586Sdelphij#endif 77246586Sdelphij 78246586Sdelphij#ifndef KTR_CPUMASK 79246586Sdelphij#define KTR_CPUMASK CPUSET_FSET 80246586Sdelphij#endif 81246586Sdelphij 82246586Sdelphij#ifndef KTR_TIME 83246586Sdelphij#define KTR_TIME get_cyclecount() 84246586Sdelphij#endif 85246586Sdelphij 86246586Sdelphij#ifndef KTR_CPU 87246586Sdelphij#define KTR_CPU PCPU_GET(cpuid) 88272425Sdelphij#endif 89272425Sdelphij 90272425Sdelphijstatic MALLOC_DEFINE(M_KTR, "KTR", "KTR"); 91272425Sdelphij 92272425SdelphijFEATURE(ktr, "Kernel support for KTR kernel tracing facility"); 93272425Sdelphij 94272425Sdelphijvolatile int ktr_idx = 0; 95272425Sdelphijuint64_t ktr_mask = KTR_MASK; 96272425Sdelphijuint64_t ktr_compile = KTR_COMPILE; 97272425Sdelphijint ktr_entries = KTR_BOOT_ENTRIES; 98272425Sdelphijint ktr_version = KTR_VERSION; 99246586Sdelphijstruct ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES]; 100246586Sdelphijstruct ktr_entry *ktr_buf = ktr_buf_init; 101246586Sdelphijcpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK); 102246586Sdelphij 103246586Sdelphijstatic SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 104246586Sdelphij "KTR options"); 105246586Sdelphij 106246586SdelphijSYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD, 107246586Sdelphij &ktr_version, 0, "Version of the KTR interface"); 108246586Sdelphij 109246586SdelphijSYSCTL_UQUAD(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD, 110246586Sdelphij &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel"); 111246586Sdelphij 112246586Sdelphijstatic int 113246586Sdelphijsysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS) 114246586Sdelphij{ 115246586Sdelphij char lktr_cpumask_str[CPUSETBUFSIZ]; 116246586Sdelphij cpuset_t imask; 117246586Sdelphij int error; 118246586Sdelphij 119246586Sdelphij cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask); 120246586Sdelphij error = sysctl_handle_string(oidp, lktr_cpumask_str, 121246586Sdelphij sizeof(lktr_cpumask_str), req); 122246586Sdelphij if (error != 0 || req->newptr == NULL) 123246586Sdelphij return (error); 124246586Sdelphij if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1) 125246586Sdelphij return (EINVAL); 126246586Sdelphij CPU_COPY(&imask, &ktr_cpumask); 127246586Sdelphij 128246586Sdelphij return (error); 129272425Sdelphij} 130272425SdelphijSYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask, 131272425Sdelphij CTLFLAG_RWTUN | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0, 132272425Sdelphij sysctl_debug_ktr_cpumask, "S", 133246586Sdelphij "Bitmask of CPUs on which KTR logging is enabled"); 134246586Sdelphij 135246586Sdelphijstatic int 136246586Sdelphijsysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS) 137246586Sdelphij{ 138246586Sdelphij int clear, error; 139246586Sdelphij 140246586Sdelphij clear = 0; 141246586Sdelphij error = sysctl_handle_int(oidp, &clear, 0, req); 142246586Sdelphij if (error || !req->newptr) 143272425Sdelphij return (error); 144272425Sdelphij 145272425Sdelphij if (clear) { 146272425Sdelphij bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries); 147246586Sdelphij ktr_idx = 0; 148246586Sdelphij } 149246586Sdelphij 150246586Sdelphij return (error); 151246586Sdelphij} 152246586SdelphijSYSCTL_PROC(_debug_ktr, OID_AUTO, clear, 153246586Sdelphij CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, 0, 154246586Sdelphij sysctl_debug_ktr_clear, "I", 155246586Sdelphij "Clear KTR Buffer"); 156246586Sdelphij 157246586Sdelphij/* 158246586Sdelphij * This is a sysctl proc so that it is serialized as !MPSAFE along with 159246586Sdelphij * the other ktr sysctl procs. 160246586Sdelphij */ 161246586Sdelphijstatic int 162246586Sdelphijsysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS) 163246586Sdelphij{ 164246586Sdelphij uint64_t mask; 165246586Sdelphij int error; 166246586Sdelphij 167246586Sdelphij mask = ktr_mask; 168246586Sdelphij error = sysctl_handle_64(oidp, &mask, 0, req); 169246586Sdelphij if (error || !req->newptr) 170246586Sdelphij return (error); 171246586Sdelphij ktr_mask = mask; 172246586Sdelphij return (error); 173246586Sdelphij} 174246586Sdelphij 175246586SdelphijSYSCTL_PROC(_debug_ktr, OID_AUTO, mask, 176246586Sdelphij CTLTYPE_U64 | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 177246586Sdelphij 0, 0, sysctl_debug_ktr_mask, "QU", 178246586Sdelphij "Bitmask of KTR event classes for which logging is enabled"); 179246586Sdelphij 180246586Sdelphij#if KTR_ENTRIES > KTR_BOOT_ENTRIES 181246586Sdelphij/* 182246586Sdelphij * A simplified version of sysctl_debug_ktr_entries. 183246586Sdelphij * No need to care about SMP, scheduling, etc. 184246586Sdelphij */ 185246586Sdelphijstatic void 186246586Sdelphijktr_entries_initializer(void *dummy __unused) 187246586Sdelphij{ 188246586Sdelphij uint64_t mask; 189246586Sdelphij 190246586Sdelphij /* Temporarily disable ktr in case malloc() is being traced. */ 191246586Sdelphij mask = ktr_mask; 192246586Sdelphij ktr_mask = 0; 193246586Sdelphij ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR, 194246586Sdelphij M_WAITOK | M_ZERO); 195246586Sdelphij memcpy(ktr_buf, ktr_buf_init + ktr_idx, 196246586Sdelphij (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf)); 197246586Sdelphij if (ktr_idx != 0) { 198246586Sdelphij memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init, 199246586Sdelphij ktr_idx * sizeof(*ktr_buf)); 200246586Sdelphij ktr_idx = KTR_BOOT_ENTRIES; 201246586Sdelphij } 202246586Sdelphij ktr_entries = KTR_ENTRIES; 203246586Sdelphij ktr_mask = mask; 204246586Sdelphij} 205246586SdelphijSYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY, 206246586Sdelphij ktr_entries_initializer, NULL); 207246586Sdelphij#endif 208246586Sdelphij 209246586Sdelphijstatic int 210246586Sdelphijsysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS) 211246586Sdelphij{ 212246586Sdelphij uint64_t mask; 213246586Sdelphij int entries, error; 214246586Sdelphij struct ktr_entry *buf, *oldbuf; 215246586Sdelphij 216246586Sdelphij entries = ktr_entries; 217246586Sdelphij error = sysctl_handle_int(oidp, &entries, 0, req); 218246586Sdelphij if (error || !req->newptr) 219246586Sdelphij return (error); 220246586Sdelphij if (entries > KTR_ENTRIES_MAX) 221246586Sdelphij return (ERANGE); 222246586Sdelphij /* Disable ktr temporarily. */ 223246586Sdelphij mask = ktr_mask; 224246586Sdelphij ktr_mask = 0; 225246586Sdelphij /* Wait for threads to go idle. */ 226246586Sdelphij if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) { 227246586Sdelphij ktr_mask = mask; 228246586Sdelphij return (error); 229246586Sdelphij } 230246586Sdelphij if (ktr_buf != ktr_buf_init) 231246586Sdelphij oldbuf = ktr_buf; 232246586Sdelphij else 233246586Sdelphij oldbuf = NULL; 234246586Sdelphij /* Allocate a new buffer. */ 235246586Sdelphij buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO); 236246586Sdelphij /* Install the new buffer and restart ktr. */ 237246586Sdelphij ktr_buf = buf; 238246586Sdelphij ktr_entries = entries; 239246586Sdelphij ktr_idx = 0; 240246586Sdelphij ktr_mask = mask; 241246586Sdelphij if (oldbuf != NULL) 242246586Sdelphij free(oldbuf, M_KTR); 243246586Sdelphij 244246586Sdelphij return (error); 245246586Sdelphij} 246246586Sdelphij 247246586SdelphijSYSCTL_PROC(_debug_ktr, OID_AUTO, entries, 248246586Sdelphij CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 249246586Sdelphij 0, 0, sysctl_debug_ktr_entries, "I", 250246586Sdelphij "Number of entries in the KTR buffer"); 251246586Sdelphij 252246586Sdelphij#ifdef KTR_VERBOSE 253246586Sdelphijint ktr_verbose = KTR_VERBOSE; 254246586SdelphijTUNABLE_INT("debug.ktr.verbose", &ktr_verbose); 255246586SdelphijSYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, ""); 256246586Sdelphij#endif 257246586Sdelphij 258246586Sdelphij#ifdef KTR_ALQ 259246586Sdelphijstruct alq *ktr_alq; 260246586Sdelphijchar ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out"; 261246586Sdelphijint ktr_alq_cnt = 0; 262246586Sdelphijint ktr_alq_depth = KTR_ENTRIES; 263246586Sdelphijint ktr_alq_enabled = 0; 264246586Sdelphijint ktr_alq_failed = 0; 265246586Sdelphijint ktr_alq_max = 0; 266246586Sdelphij 267246586SdelphijSYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0, 268246586Sdelphij "Maximum number of entries to write"); 269246586SdelphijSYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0, 270246586Sdelphij "Current number of written entries"); 271246586SdelphijSYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0, 272246586Sdelphij "Number of times we overran the buffer"); 273246586SdelphijSYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0, 274246586Sdelphij "Number of items in the write buffer"); 275246586SdelphijSYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file, 276246586Sdelphij sizeof(ktr_alq_file), "KTR logging file"); 277246586Sdelphij 278246586Sdelphijstatic int 279246586Sdelphijsysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS) 280246586Sdelphij{ 281246586Sdelphij int error; 282246586Sdelphij int enable; 283246586Sdelphij 284246586Sdelphij enable = ktr_alq_enabled; 285246586Sdelphij 286246586Sdelphij error = sysctl_handle_int(oidp, &enable, 0, req); 287246586Sdelphij if (error || !req->newptr) 288246586Sdelphij return (error); 289246586Sdelphij 290246586Sdelphij if (enable) { 291246586Sdelphij if (ktr_alq_enabled) 292246586Sdelphij return (0); 293246586Sdelphij error = alq_open(&ktr_alq, (const char *)ktr_alq_file, 294246586Sdelphij req->td->td_ucred, ALQ_DEFAULT_CMODE, 295246586Sdelphij sizeof(struct ktr_entry), ktr_alq_depth); 296246586Sdelphij if (error == 0) { 297246586Sdelphij ktr_alq_cnt = 0; 298246586Sdelphij ktr_alq_failed = 0; 299246586Sdelphij ktr_alq_enabled = 1; 300246586Sdelphij } 301246586Sdelphij } else { 302246586Sdelphij if (ktr_alq_enabled == 0) 303246586Sdelphij return (0); 304246586Sdelphij ktr_alq_enabled = 0; 305246586Sdelphij alq_close(ktr_alq); 306246586Sdelphij ktr_alq = NULL; 307246586Sdelphij } 308246586Sdelphij 309246586Sdelphij return (error); 310246586Sdelphij} 311246586SdelphijSYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable, 312246586Sdelphij CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, 0, 313246586Sdelphij sysctl_debug_ktr_alq_enable, "I", 314246586Sdelphij "Enable KTR logging"); 315246586Sdelphij#endif 316246586Sdelphij 317246586Sdelphijvoid 318246586Sdelphijktr_tracepoint(uint64_t mask, const char *file, int line, const char *format, 319246586Sdelphij u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5, 320246586Sdelphij u_long arg6) 321246586Sdelphij{ 322246586Sdelphij struct ktr_entry *entry; 323246586Sdelphij#ifdef KTR_ALQ 324246586Sdelphij struct ale *ale = NULL; 325246586Sdelphij#endif 326246586Sdelphij int newindex, saveindex; 327246586Sdelphij#if defined(KTR_VERBOSE) || defined(KTR_ALQ) 328246586Sdelphij struct thread *td; 329246586Sdelphij#endif 330 int cpu; 331 332 if (KERNEL_PANICKED() || kdb_active) 333 return; 334 if ((ktr_mask & mask) == 0 || ktr_buf == NULL) 335 return; 336 cpu = KTR_CPU; 337 if (!CPU_ISSET(cpu, &ktr_cpumask)) 338 return; 339#if defined(KTR_VERBOSE) || defined(KTR_ALQ) 340 td = curthread; 341 if (td->td_pflags & TDP_INKTR) 342 return; 343 td->td_pflags |= TDP_INKTR; 344#endif 345#ifdef KTR_ALQ 346 if (ktr_alq_enabled) { 347 if (td->td_critnest == 0 && 348 (TD_IS_IDLETHREAD(td)) == 0 && 349 td != ald_thread) { 350 if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max) 351 goto done; 352 if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) { 353 ktr_alq_failed++; 354 goto done; 355 } 356 ktr_alq_cnt++; 357 entry = (struct ktr_entry *)ale->ae_data; 358 } else { 359 goto done; 360 } 361 } else 362#endif 363 { 364 do { 365 saveindex = ktr_idx; 366 newindex = (saveindex + 1) % ktr_entries; 367 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0); 368 entry = &ktr_buf[saveindex]; 369 } 370 entry->ktr_timestamp = KTR_TIME; 371 entry->ktr_cpu = cpu; 372 entry->ktr_thread = curthread; 373 if (file != NULL) 374 while (strncmp(file, "../", 3) == 0) 375 file += 3; 376 entry->ktr_file = file; 377 entry->ktr_line = line; 378#ifdef KTR_VERBOSE 379 if (ktr_verbose) { 380#ifdef SMP 381 printf("cpu%d ", cpu); 382#endif 383 if (ktr_verbose > 1) { 384 printf("%s.%d\t", entry->ktr_file, 385 entry->ktr_line); 386 } 387 printf(format, arg1, arg2, arg3, arg4, arg5, arg6); 388 printf("\n"); 389 } 390#endif 391 entry->ktr_desc = format; 392 entry->ktr_parms[0] = arg1; 393 entry->ktr_parms[1] = arg2; 394 entry->ktr_parms[2] = arg3; 395 entry->ktr_parms[3] = arg4; 396 entry->ktr_parms[4] = arg5; 397 entry->ktr_parms[5] = arg6; 398#ifdef KTR_ALQ 399 if (ktr_alq_enabled && ale) 400 alq_post(ktr_alq, ale); 401done: 402#endif 403#if defined(KTR_VERBOSE) || defined(KTR_ALQ) 404 td->td_pflags &= ~TDP_INKTR; 405#endif 406} 407 408#ifdef DDB 409 410struct tstate { 411 int cur; 412 int first; 413}; 414static struct tstate tstate; 415static int db_ktr_verbose; 416static int db_mach_vtrace(void); 417 418DB_SHOW_COMMAND_FLAGS(ktr, db_ktr_all, DB_CMD_MEMSAFE) 419{ 420 421 tstate.cur = (ktr_idx - 1) % ktr_entries; 422 tstate.first = -1; 423 db_ktr_verbose = 0; 424 db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0; 425 db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestamp please */ 426 if (strchr(modif, 'a') != NULL) { 427 db_disable_pager(); 428 while (cncheckc() == -1) 429 if (db_mach_vtrace() == 0) 430 break; 431 } else { 432 while (!db_pager_quit) 433 if (db_mach_vtrace() == 0) 434 break; 435 } 436} 437 438static int 439db_mach_vtrace(void) 440{ 441 struct ktr_entry *kp; 442 443 if (tstate.cur == tstate.first || ktr_buf == NULL) { 444 db_printf("--- End of trace buffer ---\n"); 445 return (0); 446 } 447 kp = &ktr_buf[tstate.cur]; 448 449 /* Skip over unused entries. */ 450 if (kp->ktr_desc == NULL) { 451 db_printf("--- End of trace buffer ---\n"); 452 return (0); 453 } 454 db_printf("%d (%p", tstate.cur, kp->ktr_thread); 455#ifdef SMP 456 db_printf(":cpu%d", kp->ktr_cpu); 457#endif 458 db_printf(")"); 459 if (db_ktr_verbose >= 1) { 460 db_printf(" %10.10lld", (long long)kp->ktr_timestamp); 461 } 462 if (db_ktr_verbose >= 2) { 463 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line); 464 } 465 db_printf(": "); 466 db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1], 467 kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4], 468 kp->ktr_parms[5]); 469 db_printf("\n"); 470 471 if (tstate.first == -1) 472 tstate.first = tstate.cur; 473 474 if (--tstate.cur < 0) 475 tstate.cur = ktr_entries - 1; 476 477 return (1); 478} 479 480#endif /* DDB */ 481