sys/kern/kern_ktr.c

   1 /*
   2  * Copyright (c) 2005 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34 /*
  35  * The following copyright applies to the DDB command code:
  36  *
  37  * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org>
  38  * All rights reserved.
  39  *
  40  * Redistribution and use in source and binary forms, with or without
  41  * modification, are permitted provided that the following conditions
  42  * are met:
  43  * 1. Redistributions of source code must retain the above copyright
  44  *    notice, this list of conditions and the following disclaimer.
  45  * 2. Redistributions in binary form must reproduce the above copyright
  46  *    notice, this list of conditions and the following disclaimer in the
  47  *    documentation and/or other materials provided with the distribution.
  48  * 3. Neither the name of the author nor the names of any co-contributors
  49  *    may be used to endorse or promote products derived from this software
  50  *    without specific prior written permission.
  51  *
  52  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  62  * SUCH DAMAGE.
  63  */
  64 /*
  65  * $DragonFly: src/sys/kern/kern_ktr.c,v 1.23 2008/02/12 23:33:23 corecode Exp $
  66  */
  67 /*
  68  * Kernel tracepoint facility.
  69  */
  70
  71 #include "opt_ddb.h"
  72 #include "opt_ktr.h"
  73
  74 #include <sys/param.h>
  75 #include <sys/cons.h>
  76 #include <sys/kernel.h>
  77 #include <sys/libkern.h>
  78 #include <sys/proc.h>
  79 #include <sys/sysctl.h>
  80 #include <sys/ktr.h>
  81 #include <sys/systm.h>
  82 #include <sys/time.h>
  83 #include <sys/malloc.h>
  84 #include <sys/spinlock.h>
  85 #include <sys/thread2.h>
  86 #include <sys/spinlock2.h>
  87 #include <sys/ctype.h>
  88
  89 #include <machine/cpu.h>
  90 #include <machine/cpufunc.h>
  91 #include <machine/specialreg.h>
  92 #include <machine/md_var.h>
  93
  94 #include <ddb/ddb.h>
  95
  96 #ifndef KTR_ENTRIES
  97 #define KTR_ENTRIES             2048
  98 #endif
  99 #define KTR_ENTRIES_MASK        (KTR_ENTRIES - 1)
 100
 101 /*
 102  * test logging support.  When ktr_testlogcnt is non-zero each synchronization
 103  * interrupt will issue six back-to-back ktr logging messages on cpu 0
 104  * so the user can determine KTR logging overheads.
 105  */
 106 #if !defined(KTR_TESTLOG)
 107 #define KTR_TESTLOG     KTR_ALL
 108 #endif
 109 KTR_INFO_MASTER(testlog);
 110 #if KTR_TESTLOG
 111 KTR_INFO(KTR_TESTLOG, testlog, test1, 0, "test1", sizeof(void *) * 4);
 112 KTR_INFO(KTR_TESTLOG, testlog, test2, 1, "test2", sizeof(void *) * 4);
 113 KTR_INFO(KTR_TESTLOG, testlog, test3, 2, "test3", sizeof(void *) * 4);
 114 KTR_INFO(KTR_TESTLOG, testlog, test4, 3, "test4", 0);
 115 KTR_INFO(KTR_TESTLOG, testlog, test5, 4, "test5", 0);
 116 KTR_INFO(KTR_TESTLOG, testlog, test6, 5, "test6", 0);
 117 #ifdef SMP
 118 KTR_INFO(KTR_TESTLOG, testlog, pingpong, 6, "pingpong", 0);
 119 KTR_INFO(KTR_TESTLOG, testlog, pipeline, 7, "pipeline", 0);
 120 #endif
 121 KTR_INFO(KTR_TESTLOG, testlog, crit_beg, 8, "crit_beg", 0);
 122 KTR_INFO(KTR_TESTLOG, testlog, crit_end, 9, "crit_end", 0);
 123 KTR_INFO(KTR_TESTLOG, testlog, spin_beg, 10, "spin_beg", 0);
 124 KTR_INFO(KTR_TESTLOG, testlog, spin_end, 11, "spin_end", 0);
 125 #define logtest(name)   KTR_LOG(testlog_ ## name, 0, 0, 0, 0)
 126 #define logtest_noargs(name)    KTR_LOG(testlog_ ## name)
 127 #endif
 128
 129 MALLOC_DEFINE(M_KTR, "ktr", "ktr buffers");
 130
 131 SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RW, 0, "ktr");
 132
 133 int             ktr_entries = KTR_ENTRIES;
 134 SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD, &ktr_entries, 0, "");
 135
 136 int             ktr_version = KTR_VERSION;
 137 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD, &ktr_version, 0, "");
 138
 139 static int      ktr_stacktrace = 1;
 140 SYSCTL_INT(_debug_ktr, OID_AUTO, stacktrace, CTLFLAG_RD, &ktr_stacktrace, 0, "");
 141
 142 static int      ktr_resynchronize = 0;
 143 SYSCTL_INT(_debug_ktr, OID_AUTO, resynchronize, CTLFLAG_RW, &ktr_resynchronize, 0, "");
 144
 145 #if KTR_TESTLOG
 146 static int      ktr_testlogcnt = 0;
 147 SYSCTL_INT(_debug_ktr, OID_AUTO, testlogcnt, CTLFLAG_RW, &ktr_testlogcnt, 0, "");
 148 static int      ktr_testipicnt = 0;
 149 static int      ktr_testipicnt_remainder;
 150 SYSCTL_INT(_debug_ktr, OID_AUTO, testipicnt, CTLFLAG_RW, &ktr_testipicnt, 0, "");
 151 static int      ktr_testcritcnt = 0;
 152 SYSCTL_INT(_debug_ktr, OID_AUTO, testcritcnt, CTLFLAG_RW, &ktr_testcritcnt, 0, "");
 153 static int      ktr_testspincnt = 0;
 154 SYSCTL_INT(_debug_ktr, OID_AUTO, testspincnt, CTLFLAG_RW, &ktr_testspincnt, 0, "");
 155 #endif
 156
 157 /*
 158  * Give cpu0 a static buffer so the tracepoint facility can be used during
 159  * early boot (note however that we still use a critical section, XXX).
 160  */
 161 static struct   ktr_entry ktr_buf0[KTR_ENTRIES];
 162 struct          ktr_entry *ktr_buf[MAXCPU] = { &ktr_buf0[0] };
 163 int             ktr_idx[MAXCPU];
 164 #ifdef SMP
 165 static int      ktr_sync_state = 0;
 166 static int      ktr_sync_count;
 167 static int64_t  ktr_sync_tsc;
 168 #endif
 169 struct callout  ktr_resync_callout;
 170
 171 #ifdef KTR_VERBOSE
 172 int     ktr_verbose = KTR_VERBOSE;
 173 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
 174 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
 175 #endif
 176
 177 static void ktr_resync_callback(void *dummy __unused);
 178
 179 extern int64_t tsc_offsets[];
 180
 181 static void
 182 ktr_sysinit(void *dummy)
 183 {
 184         int i;
 185
 186         for(i = 1; i < ncpus; ++i) {
 187                 ktr_buf[i] = kmalloc(KTR_ENTRIES * sizeof(struct ktr_entry),
 188                                     M_KTR, M_WAITOK | M_ZERO);
 189         }
 190         callout_init(&ktr_resync_callout);
 191         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 192 }
 193 SYSINIT(ktr_sysinit, SI_BOOT2_KLD, SI_ORDER_ANY, ktr_sysinit, NULL);
 194
 195 /*
 196  * Try to resynchronize the TSC's for all cpus.  This is really, really nasty.
 197  * We have to send an IPIQ message to all remote cpus, wait until they
 198  * get into their IPIQ processing code loop, then do an even stricter hard
 199  * loop to get the cpus as close to synchronized as we can to get the most
 200  * accurate reading.
 201  *
 202  * This callback occurs on cpu0.
 203  */
 204 #if KTR_TESTLOG
 205 static void ktr_pingpong_remote(void *dummy);
 206 static void ktr_pipeline_remote(void *dummy);
 207 #endif
 208
 209 #if defined(SMP) && defined(_RDTSC_SUPPORTED_)
 210
 211 static void ktr_resync_remote(void *dummy);
 212 extern cpumask_t smp_active_mask;
 213
 214 /*
 215  * We use a callout callback instead of a systimer because we cannot afford
 216  * to preempt anyone to do this, or we might deadlock a spin-lock or
 217  * serializer between two cpus.
 218  */
 219 static
 220 void
 221 ktr_resync_callback(void *dummy __unused)
 222 {
 223         int count;
 224
 225         KKASSERT(mycpu->gd_cpuid == 0);
 226
 227 #if KTR_TESTLOG
 228         /*
 229          * Test logging
 230          */
 231         if (ktr_testlogcnt) {
 232                 --ktr_testlogcnt;
 233                 cpu_disable_intr();
 234                 logtest(test1);
 235                 logtest(test2);
 236                 logtest(test3);
 237                 logtest_noargs(test4);
 238                 logtest_noargs(test5);
 239                 logtest_noargs(test6);
 240                 cpu_enable_intr();
 241         }
 242
 243         /*
 244          * Test IPI messaging
 245          */
 246         if (ktr_testipicnt && ktr_testipicnt_remainder == 0 && ncpus > 1) {
 247                 ktr_testipicnt_remainder = ktr_testipicnt;
 248                 ktr_testipicnt = 0;
 249                 lwkt_send_ipiq_bycpu(1, ktr_pingpong_remote, NULL);
 250         }
 251
 252         /*
 253          * Test critical sections
 254          */
 255         if (ktr_testcritcnt) {
 256                 crit_enter();
 257                 crit_exit();
 258                 logtest_noargs(crit_beg);
 259                 for (count = ktr_testcritcnt; count; --count) {
 260                         crit_enter();
 261                         crit_exit();
 262                 }
 263                 logtest_noargs(crit_end);
 264                 ktr_testcritcnt = 0;
 265         }
 266
 267         /*
 268          * Test spinlock sections
 269          */
 270         if (ktr_testspincnt) {
 271                 struct spinlock spin;
 272
 273                 spin_init(&spin);
 274                 spin_lock_wr(&spin);
 275                 spin_unlock_wr(&spin);
 276                 logtest_noargs(spin_beg);
 277                 for (count = ktr_testspincnt; count; --count) {
 278                         spin_lock_wr(&spin);
 279                         spin_unlock_wr(&spin);
 280                 }
 281                 logtest_noargs(spin_end);
 282                 logtest_noargs(spin_beg);
 283                 for (count = ktr_testspincnt; count; --count) {
 284                         spin_lock_rd(&spin);
 285                         spin_unlock_rd(&spin);
 286                 }
 287                 logtest_noargs(spin_end);
 288                 ktr_testspincnt = 0;
 289         }
 290 #endif
 291
 292         /*
 293          * Resynchronize the TSC
 294          */
 295         if (ktr_resynchronize == 0)
 296                 goto done;
 297         if ((cpu_feature & CPUID_TSC) == 0)
 298                 return;
 299
 300         /*
 301          * Send the synchronizing IPI and wait for all cpus to get into
 302          * their spin loop.  We must process incoming IPIs while waiting
 303          * to avoid a deadlock.
 304          */
 305         crit_enter();
 306         ktr_sync_count = 0;
 307         ktr_sync_state = 1;
 308         ktr_sync_tsc = rdtsc();
 309         count = lwkt_send_ipiq_mask(mycpu->gd_other_cpus & smp_active_mask,
 310                                     (ipifunc1_t)ktr_resync_remote, NULL);
 311         while (ktr_sync_count != count)
 312                 lwkt_process_ipiq();
 313
 314         /*
 315          * Continuously update the TSC for cpu 0 while waiting for all other
 316          * cpus to finish stage 2.
 317          */
 318         cpu_disable_intr();
 319         ktr_sync_tsc = rdtsc();
 320         cpu_sfence();
 321         ktr_sync_state = 2;
 322         cpu_sfence();
 323         while (ktr_sync_count != 0) {
 324                 ktr_sync_tsc = rdtsc();
 325                 cpu_lfence();
 326                 cpu_nop();
 327         }
 328         cpu_enable_intr();
 329         crit_exit();
 330         ktr_sync_state = 0;
 331 done:
 332         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 333 }
 334
 335 /*
 336  * The remote-end of the KTR synchronization protocol runs on all cpus except
 337  * cpu 0.  Since this is an IPI function, it is entered with the current
 338  * thread in a critical section.
 339  */
 340 static void
 341 ktr_resync_remote(void *dummy __unused)
 342 {
 343         volatile int64_t tsc1 = ktr_sync_tsc;
 344         volatile int64_t tsc2;
 345
 346         /*
 347          * Inform the master that we have entered our hard loop.
 348          */
 349         KKASSERT(ktr_sync_state == 1);
 350         atomic_add_int(&ktr_sync_count, 1);
 351         while (ktr_sync_state == 1) {
 352                 lwkt_process_ipiq();
 353         }
 354
 355         /*
 356          * Now the master is in a hard loop, synchronize the TSC and
 357          * we are done.
 358          */
 359         cpu_disable_intr();
 360         KKASSERT(ktr_sync_state == 2);
 361         tsc2 = ktr_sync_tsc;
 362         if (tsc2 > tsc1)
 363                 tsc_offsets[mycpu->gd_cpuid] = rdtsc() - tsc2;
 364         atomic_subtract_int(&ktr_sync_count, 1);
 365         cpu_enable_intr();
 366 }
 367
 368 #if KTR_TESTLOG
 369
 370 static
 371 void
 372 ktr_pingpong_remote(void *dummy __unused)
 373 {
 374         int other_cpu;
 375
 376         logtest_noargs(pingpong);
 377         other_cpu = 1 - mycpu->gd_cpuid;
 378         if (ktr_testipicnt_remainder) {
 379                 --ktr_testipicnt_remainder;
 380                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pingpong_remote, NULL);
 381         } else {
 382                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 383                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 384                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 385                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 386                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 387         }
 388 }
 389
 390 static
 391 void
 392 ktr_pipeline_remote(void *dummy __unused)
 393 {
 394         logtest_noargs(pipeline);
 395 }
 396
 397 #endif
 398
 399 #else   /* !SMP */
 400
 401 /*
 402  * The resync callback for UP doesn't do anything other then run the test
 403  * log messages.  If test logging is not enabled, don't bother resetting
 404  * the callout.
 405  */
 406 static
 407 void
 408 ktr_resync_callback(void *dummy __unused)
 409 {
 410 #if KTR_TESTLOG
 411         /*
 412          * Test logging
 413          */
 414         if (ktr_testlogcnt) {
 415                 --ktr_testlogcnt;
 416                 cpu_disable_intr();
 417                 logtest(test1);
 418                 logtest(test2);
 419                 logtest(test3);
 420                 logtest_noargs(test4);
 421                 logtest_noargs(test5);
 422                 logtest_noargs(test6);
 423                 cpu_enable_intr();
 424         }
 425         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 426 #endif
 427 }
 428
 429 #endif
 430
 431 /*
 432  * KTR_WRITE_ENTRY - Primary entry point for kernel trace logging
 433  */
 434 static __inline
 435 void
 436 ktr_write_entry(struct ktr_info *info, const char *file, int line,
 437                 const void *ptr)
 438 {
 439         struct ktr_entry *entry;
 440         int cpu;
 441
 442         cpu = mycpu->gd_cpuid;
 443         if (!ktr_buf[cpu])
 444                 return;
 445
 446         crit_enter();
 447         entry = ktr_buf[cpu] + (ktr_idx[cpu] & KTR_ENTRIES_MASK);
 448         ++ktr_idx[cpu];
 449 #ifdef _RDTSC_SUPPORTED_
 450         if (cpu_feature & CPUID_TSC) {
 451 #ifdef SMP
 452                 entry->ktr_timestamp = rdtsc() - tsc_offsets[cpu];
 453 #else
 454                 entry->ktr_timestamp = rdtsc();
 455 #endif
 456         } else
 457 #endif
 458         {
 459                 entry->ktr_timestamp = get_approximate_time_t();
 460         }
 461         entry->ktr_info = info;
 462         entry->ktr_file = file;
 463         entry->ktr_line = line;
 464         crit_exit();
 465         if (info->kf_data_size > KTR_BUFSIZE)
 466                 bcopyi(ptr, entry->ktr_data, KTR_BUFSIZE);
 467         else if (info->kf_data_size)
 468                 bcopyi(ptr, entry->ktr_data, info->kf_data_size);
 469         if (ktr_stacktrace)
 470                 cpu_ktr_caller(entry);
 471 #ifdef KTR_VERBOSE
 472         if (ktr_verbose && info->kf_format) {
 473 #ifdef SMP
 474                 kprintf("cpu%d ", cpu);
 475 #endif
 476                 if (ktr_verbose > 1) {
 477                         kprintf("%s.%d\t", entry->ktr_file, entry->ktr_line);
 478                 }
 479                 kvprintf(info->kf_format, ptr);
 480                 kprintf("\n");
 481         }
 482 #endif
 483 }
 484
 485 void
 486 ktr_log(struct ktr_info *info, const char *file, int line, ...)
 487 {
 488         __va_list va;
 489
 490         if (panicstr == NULL) {
 491                 __va_start(va, line);
 492                 ktr_write_entry(info, file, line, va);
 493                 __va_end(va);
 494         }
 495 }
 496
 497 void
 498 ktr_log_ptr(struct ktr_info *info, const char *file, int line, const void *ptr)
 499 {
 500         if (panicstr == NULL) {
 501                 ktr_write_entry(info, file, line, ptr);
 502         }
 503 }
 504
 505 #ifdef DDB
 506
 507 #define NUM_LINES_PER_PAGE      19
 508
 509 struct tstate {
 510         int     cur;
 511         int     first;
 512 };
 513
 514 static  int db_ktr_verbose;
 515 static  int db_mach_vtrace(int cpu, struct ktr_entry *kp, int idx);
 516
 517 DB_SHOW_COMMAND(ktr, db_ktr_all)
 518 {
 519         int a_flag = 0;
 520         int c;
 521         int nl = 0;
 522         int i;
 523         struct tstate tstate[MAXCPU];
 524         int printcpu = -1;
 525
 526         for(i = 0; i < ncpus; i++) {
 527                 tstate[i].first = -1;
 528                 tstate[i].cur = ktr_idx[i] & KTR_ENTRIES_MASK;
 529         }
 530         db_ktr_verbose = 0;
 531         while ((c = *(modif++)) != '\0') {
 532                 if (c == 'v') {
 533                         db_ktr_verbose = 1;
 534                 }
 535                 else if (c == 'a') {
 536                         a_flag = 1;
 537                 }
 538                 else if (c == 'c') {
 539                         printcpu = 0;
 540                         while ((c = *(modif++)) != '\0') {
 541                                 if (isdigit(c)) {
 542                                         printcpu *= 10;
 543                                         printcpu += c - '0';
 544                                 }
 545                                 else {
 546                                         modif++;
 547                                         break;
 548                                 }
 549                         }
 550                         modif--;
 551                 }
 552         }
 553         if (printcpu > ncpus - 1) {
 554                 db_printf("Invalid cpu number\n");
 555                 return;
 556         }
 557         /*
 558          * Lopp throug all the buffers and print the content of them, sorted
 559          * by the timestamp.
 560          */
 561         while (1) {
 562                 int counter;
 563                 u_int64_t highest_ts;
 564                 int highest_cpu;
 565                 struct ktr_entry *kp;
 566
 567                 if (a_flag == 1 && cncheckc() != -1)
 568                         return;
 569                 highest_ts = 0;
 570                 highest_cpu = -1;
 571                 /*
 572                  * Find the lowest timestamp
 573                  */
 574                 for (i = 0, counter = 0; i < ncpus; i++) {
 575                         if (ktr_buf[i] == NULL)
 576                                 continue;
 577                         if (printcpu != -1 && printcpu != i)
 578                                 continue;
 579                         if (tstate[i].cur == -1) {
 580                                 counter++;
 581                                 if (counter == ncpus) {
 582                                         db_printf("--- End of trace buffer ---\n");
 583                                         return;
 584                                 }
 585                                 continue;
 586                         }
 587                         if (ktr_buf[i][tstate[i].cur].ktr_timestamp > highest_ts) {
 588                                 highest_ts = ktr_buf[i][tstate[i].cur].ktr_timestamp;
 589                                 highest_cpu = i;
 590                         }
 591                 }
 592                 i = highest_cpu;
 593                 KKASSERT(i != -1);
 594                 kp = &ktr_buf[i][tstate[i].cur];
 595                 if (tstate[i].first == -1)
 596                         tstate[i].first = tstate[i].cur;
 597                 if (--tstate[i].cur < 0)
 598                         tstate[i].cur = KTR_ENTRIES - 1;
 599                 if (tstate[i].first == tstate[i].cur) {
 600                         db_mach_vtrace(i, kp, tstate[i].cur + 1);
 601                         tstate[i].cur = -1;
 602                         continue;
 603                 }
 604                 if (ktr_buf[i][tstate[i].cur].ktr_info == NULL)
 605                         tstate[i].cur = -1;
 606                 if (db_more(&nl) == -1)
 607                         break;
 608                 if (db_mach_vtrace(i, kp, tstate[i].cur + 1) == 0)
 609                         tstate[i].cur = -1;
 610         }
 611 }
 612
 613 static int
 614 db_mach_vtrace(int cpu, struct ktr_entry *kp, int idx)
 615 {
 616         if (kp->ktr_info == NULL)
 617                 return(0);
 618 #ifdef SMP
 619         db_printf("cpu%d ", cpu);
 620 #endif
 621         db_printf("%d: ", idx);
 622         if (db_ktr_verbose) {
 623                 db_printf("%10.10lld %s.%d\t", (long long)kp->ktr_timestamp,
 624                     kp->ktr_file, kp->ktr_line);
 625         }
 626         db_printf("%s\t", kp->ktr_info->kf_name);
 627         db_printf("from(%p,%p) ", kp->ktr_caller1, kp->ktr_caller2);
 628         if (kp->ktr_info->kf_format) {
 629                 int32_t *args = kp->ktr_data;
 630                 db_printf(kp->ktr_info->kf_format,
 631                           args[0], args[1], args[2], args[3],
 632                           args[4], args[5], args[6], args[7],
 633                           args[8], args[9], args[10], args[11]);
 634
 635         }
 636         db_printf("\n");
 637
 638         return(1);
 639 }
 640
 641 #endif  /* DDB */