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 1.21 2007/04/30 07:18:53 dillon 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 static int32_t  ktr_cpumask = -1;
 134 TUNABLE_INT("debug.ktr.cpumask", &ktr_cpumask);
 135 SYSCTL_INT(_debug_ktr, OID_AUTO, cpumask, CTLFLAG_RW, &ktr_cpumask, 0, "");
 136
 137 static int      ktr_entries = KTR_ENTRIES;
 138 SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD, &ktr_entries, 0, "");
 139
 140 static int      ktr_version = KTR_VERSION;
 141 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD, &ktr_version, 0, "");
 142
 143 static int      ktr_stacktrace = 1;
 144 SYSCTL_INT(_debug_ktr, OID_AUTO, stacktrace, CTLFLAG_RD, &ktr_stacktrace, 0, "");
 145
 146 static int      ktr_resynchronize = 0;
 147 SYSCTL_INT(_debug_ktr, OID_AUTO, resynchronize, CTLFLAG_RW, &ktr_resynchronize, 0, "");
 148
 149 #if KTR_TESTLOG
 150 static int      ktr_testlogcnt = 0;
 151 SYSCTL_INT(_debug_ktr, OID_AUTO, testlogcnt, CTLFLAG_RW, &ktr_testlogcnt, 0, "");
 152 static int      ktr_testipicnt = 0;
 153 static int      ktr_testipicnt_remainder;
 154 SYSCTL_INT(_debug_ktr, OID_AUTO, testipicnt, CTLFLAG_RW, &ktr_testipicnt, 0, "");
 155 static int      ktr_testcritcnt = 0;
 156 SYSCTL_INT(_debug_ktr, OID_AUTO, testcritcnt, CTLFLAG_RW, &ktr_testcritcnt, 0, "");
 157 static int      ktr_testspincnt = 0;
 158 SYSCTL_INT(_debug_ktr, OID_AUTO, testspincnt, CTLFLAG_RW, &ktr_testspincnt, 0, "");
 159 #endif
 160
 161 /*
 162  * Give cpu0 a static buffer so the tracepoint facility can be used during
 163  * early boot (note however that we still use a critical section, XXX).
 164  */
 165 static struct   ktr_entry ktr_buf0[KTR_ENTRIES];
 166 static struct   ktr_entry *ktr_buf[MAXCPU] = { &ktr_buf0[0] };
 167 static int      ktr_idx[MAXCPU];
 168 #ifdef SMP
 169 static int      ktr_sync_state = 0;
 170 static int      ktr_sync_count;
 171 static int64_t  ktr_sync_tsc;
 172 #endif
 173 struct callout  ktr_resync_callout;
 174
 175 #ifdef KTR_VERBOSE
 176 int     ktr_verbose = KTR_VERBOSE;
 177 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
 178 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
 179 #endif
 180
 181 static void ktr_resync_callback(void *dummy __unused);
 182
 183 extern int64_t tsc_offsets[];
 184
 185 static void
 186 ktr_sysinit(void *dummy)
 187 {
 188         int i;
 189
 190         for(i = 1; i < ncpus; ++i) {
 191                 ktr_buf[i] = kmalloc(KTR_ENTRIES * sizeof(struct ktr_entry),
 192                                     M_KTR, M_WAITOK | M_ZERO);
 193         }
 194         callout_init(&ktr_resync_callout);
 195         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 196 }
 197 SYSINIT(ktr_sysinit, SI_BOOT2_KLD, SI_ORDER_ANY, ktr_sysinit, NULL);
 198
 199 /*
 200  * Try to resynchronize the TSC's for all cpus.  This is really, really nasty.
 201  * We have to send an IPIQ message to all remote cpus, wait until they
 202  * get into their IPIQ processing code loop, then do an even stricter hard
 203  * loop to get the cpus as close to synchronized as we can to get the most
 204  * accurate reading.
 205  *
 206  * This callback occurs on cpu0.
 207  */
 208 #if KTR_TESTLOG
 209 static void ktr_pingpong_remote(void *dummy);
 210 static void ktr_pipeline_remote(void *dummy);
 211 #endif
 212
 213 #if defined(SMP) && defined(_RDTSC_SUPPORTED_)
 214
 215 static void ktr_resync_remote(void *dummy);
 216 extern cpumask_t smp_active_mask;
 217
 218 /*
 219  * We use a callout callback instead of a systimer because we cannot afford
 220  * to preempt anyone to do this, or we might deadlock a spin-lock or
 221  * serializer between two cpus.
 222  */
 223 static
 224 void
 225 ktr_resync_callback(void *dummy __unused)
 226 {
 227         int count;
 228
 229         KKASSERT(mycpu->gd_cpuid == 0);
 230
 231 #if KTR_TESTLOG
 232         /*
 233          * Test logging
 234          */
 235         if (ktr_testlogcnt) {
 236                 --ktr_testlogcnt;
 237                 cpu_disable_intr();
 238                 logtest(test1);
 239                 logtest(test2);
 240                 logtest(test3);
 241                 logtest_noargs(test4);
 242                 logtest_noargs(test5);
 243                 logtest_noargs(test6);
 244                 cpu_enable_intr();
 245         }
 246
 247         /*
 248          * Test IPI messaging
 249          */
 250         if (ktr_testipicnt && ktr_testipicnt_remainder == 0 && ncpus > 1) {
 251                 ktr_testipicnt_remainder = ktr_testipicnt;
 252                 ktr_testipicnt = 0;
 253                 lwkt_send_ipiq_bycpu(1, ktr_pingpong_remote, NULL);
 254         }
 255
 256         /*
 257          * Test critical sections
 258          */
 259         if (ktr_testcritcnt) {
 260                 crit_enter();
 261                 crit_exit();
 262                 logtest_noargs(crit_beg);
 263                 for (count = ktr_testcritcnt; count; --count) {
 264                         crit_enter();
 265                         crit_exit();
 266                 }
 267                 logtest_noargs(crit_end);
 268                 ktr_testcritcnt = 0;
 269         }
 270
 271         /*
 272          * Test spinlock sections
 273          */
 274         if (ktr_testspincnt) {
 275                 struct spinlock spin;
 276
 277                 spin_init(&spin);
 278                 spin_lock_wr(&spin);
 279                 spin_unlock_wr(&spin);
 280                 logtest_noargs(spin_beg);
 281                 for (count = ktr_testspincnt; count; --count) {
 282                         spin_lock_wr(&spin);
 283                         spin_unlock_wr(&spin);
 284                 }
 285                 logtest_noargs(spin_end);
 286                 logtest_noargs(spin_beg);
 287                 for (count = ktr_testspincnt; count; --count) {
 288                         spin_lock_rd(&spin);
 289                         spin_unlock_rd(&spin);
 290                 }
 291                 logtest_noargs(spin_end);
 292                 ktr_testspincnt = 0;
 293         }
 294 #endif
 295
 296         /*
 297          * Resynchronize the TSC
 298          */
 299         if (ktr_resynchronize == 0)
 300                 goto done;
 301         if ((cpu_feature & CPUID_TSC) == 0)
 302                 return;
 303
 304         /*
 305          * Send the synchronizing IPI and wait for all cpus to get into
 306          * their spin loop.  We must process incoming IPIs while waiting
 307          * to avoid a deadlock.
 308          */
 309         crit_enter();
 310         ktr_sync_count = 0;
 311         ktr_sync_state = 1;
 312         ktr_sync_tsc = rdtsc();
 313         count = lwkt_send_ipiq_mask(mycpu->gd_other_cpus & smp_active_mask,
 314                                     (ipifunc1_t)ktr_resync_remote, NULL);
 315         while (ktr_sync_count != count)
 316                 lwkt_process_ipiq();
 317
 318         /*
 319          * Continuously update the TSC for cpu 0 while waiting for all other
 320          * cpus to finish stage 2.
 321          */
 322         cpu_disable_intr();
 323         ktr_sync_tsc = rdtsc();
 324         cpu_sfence();
 325         ktr_sync_state = 2;
 326         cpu_sfence();
 327         while (ktr_sync_count != 0) {
 328                 ktr_sync_tsc = rdtsc();
 329                 cpu_lfence();
 330                 cpu_nop();
 331         }
 332         cpu_enable_intr();
 333         crit_exit();
 334         ktr_sync_state = 0;
 335 done:
 336         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 337 }
 338
 339 /*
 340  * The remote-end of the KTR synchronization protocol runs on all cpus except
 341  * cpu 0.  Since this is an IPI function, it is entered with the current
 342  * thread in a critical section.
 343  */
 344 static void
 345 ktr_resync_remote(void *dummy __unused)
 346 {
 347         volatile int64_t tsc1 = ktr_sync_tsc;
 348         volatile int64_t tsc2;
 349
 350         /*
 351          * Inform the master that we have entered our hard loop.
 352          */
 353         KKASSERT(ktr_sync_state == 1);
 354         atomic_add_int(&ktr_sync_count, 1);
 355         while (ktr_sync_state == 1) {
 356                 lwkt_process_ipiq();
 357         }
 358
 359         /*
 360          * Now the master is in a hard loop, synchronize the TSC and
 361          * we are done.
 362          */
 363         cpu_disable_intr();
 364         KKASSERT(ktr_sync_state == 2);
 365         tsc2 = ktr_sync_tsc;
 366         if (tsc2 > tsc1)
 367                 tsc_offsets[mycpu->gd_cpuid] = rdtsc() - tsc2;
 368         atomic_subtract_int(&ktr_sync_count, 1);
 369         cpu_enable_intr();
 370 }
 371
 372 #if KTR_TESTLOG
 373
 374 static
 375 void
 376 ktr_pingpong_remote(void *dummy __unused)
 377 {
 378         int other_cpu;
 379
 380         logtest_noargs(pingpong);
 381         other_cpu = 1 - mycpu->gd_cpuid;
 382         if (ktr_testipicnt_remainder) {
 383                 --ktr_testipicnt_remainder;
 384                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pingpong_remote, NULL);
 385         } else {
 386                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 387                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 388                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 389                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 390                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 391         }
 392 }
 393
 394 static
 395 void
 396 ktr_pipeline_remote(void *dummy __unused)
 397 {
 398         logtest_noargs(pipeline);
 399 }
 400
 401 #endif
 402
 403 #else   /* !SMP */
 404
 405 /*
 406  * The resync callback for UP doesn't do anything other then run the test
 407  * log messages.  If test logging is not enabled, don't bother resetting
 408  * the callout.
 409  */
 410 static
 411 void
 412 ktr_resync_callback(void *dummy __unused)
 413 {
 414 #if KTR_TESTLOG
 415         /*
 416          * Test logging
 417          */
 418         if (ktr_testlogcnt) {
 419                 --ktr_testlogcnt;
 420                 cpu_disable_intr();
 421                 logtest(test1);
 422                 logtest(test2);
 423                 logtest(test3);
 424                 logtest_noargs(test4);
 425                 logtest_noargs(test5);
 426                 logtest_noargs(test6);
 427                 cpu_enable_intr();
 428         }
 429         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 430 #endif
 431 }
 432
 433 #endif
 434
 435 /*
 436  * KTR_WRITE_ENTRY - Primary entry point for kernel trace logging
 437  */
 438 static __inline
 439 void
 440 ktr_write_entry(struct ktr_info *info, const char *file, int line,
 441                 const void *ptr)
 442 {
 443         struct ktr_entry *entry;
 444         int cpu;
 445
 446         cpu = mycpu->gd_cpuid;
 447         if (!ktr_buf[cpu])
 448                 return;
 449
 450         crit_enter();
 451         entry = ktr_buf[cpu] + (ktr_idx[cpu] & KTR_ENTRIES_MASK);
 452         ++ktr_idx[cpu];
 453 #ifdef _RDTSC_SUPPORTED_
 454         if (cpu_feature & CPUID_TSC) {
 455 #ifdef SMP
 456                 entry->ktr_timestamp = rdtsc() - tsc_offsets[cpu];
 457 #else
 458                 entry->ktr_timestamp = rdtsc();
 459 #endif
 460         } else
 461 #endif
 462         {
 463                 entry->ktr_timestamp = get_approximate_time_t();
 464         }
 465         entry->ktr_info = info;
 466         entry->ktr_file = file;
 467         entry->ktr_line = line;
 468         crit_exit();
 469         if (info->kf_data_size > KTR_BUFSIZE)
 470                 bcopyi(ptr, entry->ktr_data, KTR_BUFSIZE);
 471         else if (info->kf_data_size)
 472                 bcopyi(ptr, entry->ktr_data, info->kf_data_size);
 473         if (ktr_stacktrace)
 474                 cpu_ktr_caller(entry);
 475 #ifdef KTR_VERBOSE
 476         if (ktr_verbose && info->kf_format) {
 477 #ifdef SMP
 478                 kprintf("cpu%d ", cpu);
 479 #endif
 480                 if (ktr_verbose > 1) {
 481                         kprintf("%s.%d\t", entry->ktr_file, entry->ktr_line);
 482                 }
 483                 kvprintf(info->kf_format, ptr);
 484                 kprintf("\n");
 485         }
 486 #endif
 487 }
 488
 489 void
 490 ktr_log(struct ktr_info *info, const char *file, int line, ...)
 491 {
 492         __va_list va;
 493
 494         if (panicstr == NULL) {
 495                 __va_start(va, line);
 496                 ktr_write_entry(info, file, line, va);
 497                 __va_end(va);
 498         }
 499 }
 500
 501 void
 502 ktr_log_ptr(struct ktr_info *info, const char *file, int line, const void *ptr)
 503 {
 504         if (panicstr == NULL) {
 505                 ktr_write_entry(info, file, line, ptr);
 506         }
 507 }
 508
 509 #ifdef DDB
 510
 511 #define NUM_LINES_PER_PAGE      19
 512
 513 struct tstate {
 514         int     cur;
 515         int     first;
 516 };
 517
 518 static  int db_ktr_verbose;
 519 static  int db_mach_vtrace(int cpu, struct ktr_entry *kp, int idx);
 520
 521 DB_SHOW_COMMAND(ktr, db_ktr_all)
 522 {
 523         int a_flag = 0;
 524         int c;
 525         int nl = 0;
 526         int i;
 527         struct tstate tstate[MAXCPU];
 528         int printcpu = -1;
 529
 530         for(i = 0; i < ncpus; i++) {
 531                 tstate[i].first = -1;
 532                 tstate[i].cur = ktr_idx[i] & KTR_ENTRIES_MASK;
 533         }
 534         db_ktr_verbose = 0;
 535         while ((c = *(modif++)) != '\0') {
 536                 if (c == 'v') {
 537                         db_ktr_verbose = 1;
 538                 }
 539                 else if (c == 'a') {
 540                         a_flag = 1;
 541                 }
 542                 else if (c == 'c') {
 543                         printcpu = 0;
 544                         while ((c = *(modif++)) != '\0') {
 545                                 if (isdigit(c)) {
 546                                         printcpu *= 10;
 547                                         printcpu += c - '0';
 548                                 }
 549                                 else {
 550                                         modif++;
 551                                         break;
 552                                 }
 553                         }
 554                         modif--;
 555                 }
 556         }
 557         if (printcpu > ncpus - 1) {
 558                 db_printf("Invalid cpu number\n");
 559                 return;
 560         }
 561         /*
 562          * Lopp throug all the buffers and print the content of them, sorted
 563          * by the timestamp.
 564          */
 565         while (1) {
 566                 int counter;
 567                 u_int64_t highest_ts;
 568                 int highest_cpu;
 569                 struct ktr_entry *kp;
 570
 571                 if (a_flag == 1 && cncheckc() != -1)
 572                         return;
 573                 highest_ts = 0;
 574                 highest_cpu = -1;
 575                 /*
 576                  * Find the lowest timestamp
 577                  */
 578                 for (i = 0, counter = 0; i < ncpus; i++) {
 579                         if (ktr_buf[i] == NULL)
 580                                 continue;
 581                         if (printcpu != -1 && printcpu != i)
 582                                 continue;
 583                         if (tstate[i].cur == -1) {
 584                                 counter++;
 585                                 if (counter == ncpus) {
 586                                         db_printf("--- End of trace buffer ---\n");
 587                                         return;
 588                                 }
 589                                 continue;
 590                         }
 591                         if (ktr_buf[i][tstate[i].cur].ktr_timestamp > highest_ts) {
 592                                 highest_ts = ktr_buf[i][tstate[i].cur].ktr_timestamp;
 593                                 highest_cpu = i;
 594                         }
 595                 }
 596                 i = highest_cpu;
 597                 KKASSERT(i != -1);
 598                 kp = &ktr_buf[i][tstate[i].cur];
 599                 if (tstate[i].first == -1)
 600                         tstate[i].first = tstate[i].cur;
 601                 if (--tstate[i].cur < 0)
 602                         tstate[i].cur = KTR_ENTRIES - 1;
 603                 if (tstate[i].first == tstate[i].cur) {
 604                         db_mach_vtrace(i, kp, tstate[i].cur + 1);
 605                         tstate[i].cur = -1;
 606                         continue;
 607                 }
 608                 if (ktr_buf[i][tstate[i].cur].ktr_info == NULL)
 609                         tstate[i].cur = -1;
 610                 if (db_more(&nl) == -1)
 611                         break;
 612                 if (db_mach_vtrace(i, kp, tstate[i].cur + 1) == 0)
 613                         tstate[i].cur = -1;
 614         }
 615 }
 616
 617 static int
 618 db_mach_vtrace(int cpu, struct ktr_entry *kp, int idx)
 619 {
 620         if (kp->ktr_info == NULL)
 621                 return(0);
 622 #ifdef SMP
 623         db_printf("cpu%d ", cpu);
 624 #endif
 625         db_printf("%d: ", idx);
 626         if (db_ktr_verbose) {
 627                 db_printf("%10.10lld %s.%d\t", (long long)kp->ktr_timestamp,
 628                     kp->ktr_file, kp->ktr_line);
 629         }
 630         db_printf("%s\t", kp->ktr_info->kf_name);
 631         db_printf("from(%p,%p) ", kp->ktr_caller1, kp->ktr_caller2);
 632         if (kp->ktr_info->kf_format) {
 633                 int32_t *args = kp->ktr_data;
 634                 db_printf(kp->ktr_info->kf_format,
 635                           args[0], args[1], args[2], args[3],
 636                           args[4], args[5], args[6], args[7],
 637                           args[8], args[9], args[10], args[11]);
 638
 639         }
 640         db_printf("\n");
 641
 642         return(1);
 643 }
 644
 645 #endif  /* DDB */