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 /*
  66  * Kernel tracepoint facility.
  67  */
  68
  69 #include "opt_ddb.h"
  70 #include "opt_ktr.h"
  71
  72 #include <sys/param.h>
  73 #include <sys/cons.h>
  74 #include <sys/kernel.h>
  75 #include <sys/libkern.h>
  76 #include <sys/proc.h>
  77 #include <sys/sysctl.h>
  78 #include <sys/ktr.h>
  79 #include <sys/systm.h>
  80 #include <sys/time.h>
  81 #include <sys/malloc.h>
  82 #include <sys/spinlock.h>
  83 #include <sys/kbio.h>
  84 #include <sys/ctype.h>
  85 #include <sys/limits.h>
  86
  87 #include <sys/thread2.h>
  88 #include <sys/spinlock2.h>
  89
  90 #include <machine/cpu.h>
  91 #include <machine/cpufunc.h>
  92 #include <machine/specialreg.h>
  93 #include <machine/md_var.h>
  94
  95 #include <ddb/ddb.h>
  96
  97 #ifndef KTR_ENTRIES
  98 #define KTR_ENTRIES             2048
  99 #elif (KTR_ENTRIES & KTR_ENTRIES - 1)
 100 #error KTR_ENTRIES must be a power of two
 101 #endif
 102 #define KTR_ENTRIES_MASK        (KTR_ENTRIES - 1)
 103
 104 /*
 105  * Used by earlier boot; default value consumes ~64K BSS.
 106  *
 107  * NOTE:
 108  * We use a small value here; this prevents kernel or module loading
 109  * failure due to excessive BSS usage if KTR_ENTRIES is large.
 110  */
 111 #if (KTR_ENTRIES < 256)
 112 #define KTR_ENTRIES_BOOT0       KTR_ENTRIES
 113 #else
 114 #define KTR_ENTRIES_BOOT0       256
 115 #endif
 116 #define KTR_ENTRIES_BOOT0_MASK  (KTR_ENTRIES_BOOT0 - 1)
 117
 118 /*
 119  * test logging support.  When ktr_testlogcnt is non-zero each synchronization
 120  * interrupt will issue six back-to-back ktr logging messages on cpu 0
 121  * so the user can determine KTR logging overheads.
 122  */
 123 #if !defined(KTR_TESTLOG)
 124 #define KTR_TESTLOG     KTR_ALL
 125 #endif
 126 KTR_INFO_MASTER(testlog);
 127 #if KTR_TESTLOG
 128 KTR_INFO(KTR_TESTLOG, testlog, charfmt, 0,
 129     "charfmt %hhd %hhi %#hho %hhu %#hhx %#hhX\n",
 130     signed char d1, signed char d2,
 131     unsigned char d3, unsigned char d4,
 132     unsigned char d5, unsigned char d6);
 133 KTR_INFO(KTR_TESTLOG, testlog, shortfmt, 1,
 134     "shortfmt %hd %hi %#ho %hu %#hx %#hX\n",
 135     short d1, short d2,
 136     unsigned short d3, unsigned short d4,
 137     unsigned short d5, unsigned short d6);
 138 KTR_INFO(KTR_TESTLOG, testlog, longfmt, 2,
 139     "longfmt %ld %li %#lo %lu %#lx %#lX\n",
 140     long d1, long d2,
 141     unsigned long d3, unsigned long d4,
 142     unsigned long d5, unsigned long d6);
 143 KTR_INFO(KTR_TESTLOG, testlog, longlongfmt, 3,
 144     "longlongfmt %lld %lli %#llo %llu %#llx %#llX\n",
 145     long long d1, long long d2,
 146     unsigned long long d3, unsigned long long d4,
 147     unsigned long long d5, unsigned long long d6);
 148 KTR_INFO(KTR_TESTLOG, testlog, intmaxfmt, 4,
 149     "intmaxfmt %jd %ji %#jo %ju %#jx %#jX\n",
 150     intmax_t d1, intmax_t d2,
 151     uintmax_t d3, uintmax_t d4,
 152     uintmax_t d5, uintmax_t d6);
 153 KTR_INFO(KTR_TESTLOG, testlog, ptrdifffmt, 5,
 154     "ptrdifffmt %td %ti\n",
 155     ptrdiff_t d1, ptrdiff_t d2);
 156 KTR_INFO(KTR_TESTLOG, testlog, sizefmt, 6,
 157     "sizefmt %zd %zi %#zo %zu %#zx %#zX\n",
 158     ssize_t d1, ssize_t d2,
 159     size_t d3, size_t d4,
 160     size_t d5, size_t d6);
 161 KTR_INFO(KTR_TESTLOG, testlog, pingpong, 17, "pingpong");
 162 KTR_INFO(KTR_TESTLOG, testlog, pipeline, 18, "pipeline");
 163 KTR_INFO(KTR_TESTLOG, testlog, crit_beg, 19, "crit_beg");
 164 KTR_INFO(KTR_TESTLOG, testlog, crit_end, 20, "crit_end");
 165 KTR_INFO(KTR_TESTLOG, testlog, spin_beg, 21, "spin_beg");
 166 KTR_INFO(KTR_TESTLOG, testlog, spin_end, 22, "spin_end");
 167 #define logtest_noargs(name)    KTR_LOG(testlog_ ## name)
 168 #endif
 169
 170 MALLOC_DEFINE(M_KTR, "ktr", "ktr buffers");
 171
 172 SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RW, 0, "ktr");
 173
 174 static int      ktr_entries = KTR_ENTRIES_BOOT0;
 175 SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD, &ktr_entries, 0,
 176     "Size of the event buffer");
 177 static int      ktr_entries_mask = KTR_ENTRIES_BOOT0_MASK;
 178
 179 static int      ktr_version = KTR_VERSION;
 180 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD, &ktr_version, 0, "");
 181
 182 static int      ktr_stacktrace = 1;
 183 SYSCTL_INT(_debug_ktr, OID_AUTO, stacktrace, CTLFLAG_RD, &ktr_stacktrace, 0, "");
 184
 185 static int      ktr_resynchronize = 0;
 186 SYSCTL_INT(_debug_ktr, OID_AUTO, resynchronize, CTLFLAG_RW,
 187     &ktr_resynchronize, 0, "Resynchronize TSC 10 times a second");
 188
 189 #if KTR_TESTLOG
 190 static int      ktr_testlogcnt = 0;
 191 SYSCTL_INT(_debug_ktr, OID_AUTO, testlogcnt, CTLFLAG_RW, &ktr_testlogcnt, 0, "");
 192 static int      ktr_testipicnt = 0;
 193 static int      ktr_testipicnt_remainder;
 194 SYSCTL_INT(_debug_ktr, OID_AUTO, testipicnt, CTLFLAG_RW, &ktr_testipicnt, 0, "");
 195 static int      ktr_testcritcnt = 0;
 196 SYSCTL_INT(_debug_ktr, OID_AUTO, testcritcnt, CTLFLAG_RW, &ktr_testcritcnt, 0, "");
 197 static int      ktr_testspincnt = 0;
 198 SYSCTL_INT(_debug_ktr, OID_AUTO, testspincnt, CTLFLAG_RW, &ktr_testspincnt, 0, "");
 199 #endif
 200
 201 /*
 202  * Give cpu0 a static buffer so the tracepoint facility can be used during
 203  * early boot (note however that we still use a critical section, XXX).
 204  */
 205 static struct   ktr_entry ktr_buf0[KTR_ENTRIES_BOOT0];
 206
 207 struct ktr_cpu ktr_cpu[MAXCPU] = {
 208         { .core.ktr_buf = &ktr_buf0[0] }
 209 };
 210
 211 static int64_t  ktr_sync_tsc;
 212 struct callout  ktr_resync_callout;
 213
 214 #ifdef KTR_VERBOSE
 215 int     ktr_verbose = KTR_VERBOSE;
 216 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
 217 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0,
 218     "Log events to the console as well");
 219 #endif
 220
 221 static void ktr_resync_callback(void *dummy __unused);
 222
 223 extern int64_t tsc_offsets[];
 224
 225 static void
 226 ktr_sysinit(void *dummy)
 227 {
 228         struct ktr_cpu_core *kcpu;
 229         int i;
 230
 231         for (i = 0; i < ncpus; ++i) {
 232                 kcpu = &ktr_cpu[i].core;
 233                 kcpu->ktr_buf = kmalloc(KTR_ENTRIES * sizeof(struct ktr_entry),
 234                                         M_KTR, M_WAITOK | M_ZERO);
 235                 if (i == 0) {
 236                         /* Migrate ktrs on CPU0 to the new location */
 237                         memcpy(kcpu->ktr_buf, ktr_buf0, sizeof(ktr_buf0));
 238                 }
 239         }
 240         cpu_sfence();
 241         ktr_entries = KTR_ENTRIES;
 242         ktr_entries_mask = KTR_ENTRIES_MASK;
 243
 244         callout_init_mp(&ktr_resync_callout);
 245         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 246 }
 247 SYSINIT(ktr_sysinit, SI_BOOT2_KLD, SI_ORDER_ANY, ktr_sysinit, NULL);
 248
 249 /*
 250  * Try to resynchronize the TSC's for all cpus.  This is really, really nasty.
 251  * We have to send an IPIQ message to all remote cpus, wait until they
 252  * get into their IPIQ processing code loop, then do an even stricter hard
 253  * loop to get the cpus as close to synchronized as we can to get the most
 254  * accurate reading.
 255  *
 256  * This callback occurs on cpu0.
 257  */
 258 #if KTR_TESTLOG
 259 static void ktr_pingpong_remote(void *dummy);
 260 static void ktr_pipeline_remote(void *dummy);
 261 #endif
 262
 263 #ifdef _RDTSC_SUPPORTED_
 264
 265 static void ktr_resync_remote(void *dummy);
 266
 267 /*
 268  * We use a callout callback instead of a systimer because we cannot afford
 269  * to preempt anyone to do this, or we might deadlock a spin-lock or
 270  * serializer between two cpus.
 271  */
 272 static
 273 void
 274 ktr_resync_callback(void *dummy __unused)
 275 {
 276         struct lwkt_cpusync cs;
 277 #if KTR_TESTLOG
 278         int count;
 279 #endif
 280
 281         KKASSERT(mycpu->gd_cpuid == 0);
 282
 283 #if KTR_TESTLOG
 284         /*
 285          * Test logging
 286          */
 287         if (ktr_testlogcnt) {
 288                 --ktr_testlogcnt;
 289                 cpu_disable_intr();
 290                 KTR_LOG(testlog_charfmt,
 291                     (signed char)UCHAR_MAX, (signed char)UCHAR_MAX,
 292                     (unsigned char)-1, (unsigned char)-1,
 293                     (unsigned char)-1, (unsigned char)-1);
 294                 KTR_LOG(testlog_shortfmt,
 295                     (short)USHRT_MAX, (short)USHRT_MAX,
 296                     (unsigned short)-1, (unsigned short)-1,
 297                     (unsigned short)-1, (unsigned short)-1);
 298                 KTR_LOG(testlog_longfmt,
 299                     (long)ULONG_MAX, (long)ULONG_MAX,
 300                     (unsigned long)-1, (unsigned long)-1,
 301                     (unsigned long)-1, (unsigned long)-1);
 302                 KTR_LOG(testlog_longlongfmt,
 303                     (long long)ULLONG_MAX, (long long)ULLONG_MAX,
 304                     (unsigned long long)-1, (unsigned long long)-1,
 305                     (unsigned long long)-1, (unsigned long long)-1);
 306                 KTR_LOG(testlog_intmaxfmt,
 307                     (intmax_t)UINTMAX_MAX, (intmax_t)UINTMAX_MAX,
 308                     (uintmax_t)-1, (uintmax_t)-1,
 309                     (uintmax_t)-1, (uintmax_t)-1);
 310                 KTR_LOG(testlog_ptrdifffmt,
 311                     (ptrdiff_t)PTRDIFF_MAX, (ptrdiff_t)PTRDIFF_MAX);
 312                 KTR_LOG(testlog_sizefmt,
 313                     (ssize_t)SIZE_T_MAX, (ssize_t)SIZE_T_MAX,
 314                     (size_t)-1, (size_t)-1,
 315                     (size_t)-1, (size_t)-1);
 316                 cpu_enable_intr();
 317         }
 318
 319         /*
 320          * Test IPI messaging
 321          */
 322         if (ktr_testipicnt && ktr_testipicnt_remainder == 0 && ncpus > 1) {
 323                 ktr_testipicnt_remainder = ktr_testipicnt;
 324                 ktr_testipicnt = 0;
 325                 lwkt_send_ipiq_bycpu(1, ktr_pingpong_remote, NULL);
 326         }
 327
 328         /*
 329          * Test critical sections
 330          */
 331         if (ktr_testcritcnt) {
 332                 crit_enter();
 333                 crit_exit();
 334                 logtest_noargs(crit_beg);
 335                 for (count = ktr_testcritcnt; count; --count) {
 336                         crit_enter();
 337                         crit_exit();
 338                 }
 339                 logtest_noargs(crit_end);
 340                 ktr_testcritcnt = 0;
 341         }
 342
 343         /*
 344          * Test spinlock sections
 345          */
 346         if (ktr_testspincnt) {
 347                 struct spinlock spin;
 348
 349                 spin_init(&spin, "ktrresync");
 350                 spin_lock(&spin);
 351                 spin_unlock(&spin);
 352                 logtest_noargs(spin_beg);
 353                 for (count = ktr_testspincnt; count; --count) {
 354                         spin_lock(&spin);
 355                         spin_unlock(&spin);
 356                 }
 357                 logtest_noargs(spin_end);
 358                 ktr_testspincnt = 0;
 359         }
 360 #endif
 361
 362         /*
 363          * Resynchronize the TSC
 364          */
 365         if (ktr_resynchronize == 0)
 366                 goto done;
 367         if ((cpu_feature & CPUID_TSC) == 0)
 368                 return;
 369
 370         crit_enter();
 371         lwkt_cpusync_init(&cs, smp_active_mask, ktr_resync_remote,
 372                           (void *)(intptr_t)mycpu->gd_cpuid);
 373         lwkt_cpusync_interlock(&cs);
 374         ktr_sync_tsc = rdtsc();
 375         lwkt_cpusync_deinterlock(&cs);
 376         crit_exit();
 377 done:
 378         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 379 }
 380
 381 /*
 382  * The remote-end of the KTR synchronization protocol runs on all cpus.
 383  * The one we run on the controlling cpu updates its tsc continuously
 384  * until the others have finished syncing (theoretically), but we don't
 385  * loop forever.
 386  *
 387  * This is a bit ad-hoc but we need to avoid livelocking inside an IPI
 388  * callback.  rdtsc() is a synchronizing instruction (I think).
 389  */
 390 static void
 391 ktr_resync_remote(void *arg)
 392 {
 393         globaldata_t gd = mycpu;
 394         int64_t delta;
 395         int i;
 396
 397         if (gd->gd_cpuid == (int)(intptr_t)arg) {
 398                 for (i = 0; i < 2000; ++i)
 399                         ktr_sync_tsc = rdtsc();
 400         } else {
 401                 delta = rdtsc() - ktr_sync_tsc;
 402                 if (tsc_offsets[gd->gd_cpuid] == 0)
 403                         tsc_offsets[gd->gd_cpuid] = delta;
 404                 tsc_offsets[gd->gd_cpuid] =
 405                         (tsc_offsets[gd->gd_cpuid] * 7 + delta) / 8;
 406         }
 407 }
 408
 409 #if KTR_TESTLOG
 410
 411 static
 412 void
 413 ktr_pingpong_remote(void *dummy __unused)
 414 {
 415         int other_cpu;
 416
 417         logtest_noargs(pingpong);
 418         other_cpu = 1 - mycpu->gd_cpuid;
 419         if (ktr_testipicnt_remainder) {
 420                 --ktr_testipicnt_remainder;
 421                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pingpong_remote, NULL);
 422         } else {
 423                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 424                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 425                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 426                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 427                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 428         }
 429 }
 430
 431 static
 432 void
 433 ktr_pipeline_remote(void *dummy __unused)
 434 {
 435         logtest_noargs(pipeline);
 436 }
 437
 438 #endif
 439
 440 #else   /* !_RDTSC_SUPPORTED_ */
 441
 442 /*
 443  * The resync callback for UP doesn't do anything other then run the test
 444  * log messages.  If test logging is not enabled, don't bother resetting
 445  * the callout.
 446  */
 447 static
 448 void
 449 ktr_resync_callback(void *dummy __unused)
 450 {
 451 #if KTR_TESTLOG
 452         /*
 453          * Test logging
 454          */
 455         if (ktr_testlogcnt) {
 456                 --ktr_testlogcnt;
 457                 cpu_disable_intr();
 458                 KTR_LOG(testlog_charfmt,
 459                     (signed char)UCHAR_MAX, (signed char)UCHAR_MAX,
 460                     (unsigned char)-1, (unsigned char)-1,
 461                     (unsigned char)-1, (unsigned char)-1);
 462                 KTR_LOG(testlog_shortfmt,
 463                     (short)USHRT_MAX, (short)USHRT_MAX,
 464                     (unsigned short)-1, (unsigned short)-1,
 465                     (unsigned short)-1, (unsigned short)-1);
 466                 KTR_LOG(testlog_longfmt,
 467                     (long)ULONG_MAX, (long)ULONG_MAX,
 468                     (unsigned long)-1, (unsigned long)-1,
 469                     (unsigned long)-1, (unsigned long)-1);
 470                 KTR_LOG(testlog_longlongfmt,
 471                     (long long)ULLONG_MAX, (long long)ULLONG_MAX,
 472                     (unsigned long long)-1, (unsigned long long)-1,
 473                     (unsigned long long)-1, (unsigned long long)-1);
 474                 KTR_LOG(testlog_intmaxfmt,
 475                     (intmax_t)UINTMAX_MAX, (intmax_t)UINTMAX_MAX,
 476                     (uintmax_t)-1, (uintmax_t)-1,
 477                     (uintmax_t)-1, (uintmax_t)-1);
 478                 KTR_LOG(testlog_ptrdifffmt,
 479                     (ptrdiff_t)PTRDIFF_MAX, (ptrdiff_t)PTRDIFF_MAX);
 480                 KTR_LOG(testlog_sizefmt,
 481                     (ssize_t)SIZE_T_MAX, (ssize_t)SIZE_T_MAX,
 482                     (size_t)-1, (size_t)-1,
 483                     (size_t)-1, (size_t)-1);
 484                 cpu_enable_intr();
 485         }
 486         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 487 #endif
 488 }
 489
 490 #endif
 491
 492 /*
 493  * Setup the next empty slot and return it to the caller to store the data
 494  * directly.
 495  */
 496 struct ktr_entry *
 497 ktr_begin_write_entry(struct ktr_info *info, const char *file, int line)
 498 {
 499         struct ktr_cpu_core *kcpu;
 500         struct ktr_entry *entry;
 501         int cpu;
 502
 503         cpu = mycpu->gd_cpuid;
 504         kcpu = &ktr_cpu[cpu].core;
 505         if (panicstr)                   /* stop logging during panic */
 506                 return NULL;
 507         if (kcpu->ktr_buf == NULL)      /* too early in boot */
 508                 return NULL;
 509
 510         crit_enter();
 511         entry = kcpu->ktr_buf + (kcpu->ktr_idx & ktr_entries_mask);
 512         ++kcpu->ktr_idx;
 513 #ifdef _RDTSC_SUPPORTED_
 514         if (cpu_feature & CPUID_TSC) {
 515                 entry->ktr_timestamp = rdtsc() - tsc_offsets[cpu];
 516         } else
 517 #endif
 518         {
 519                 entry->ktr_timestamp = get_approximate_time_t();
 520         }
 521         entry->ktr_info = info;
 522         entry->ktr_file = file;
 523         entry->ktr_line = line;
 524         crit_exit();
 525         return entry;
 526 }
 527
 528 int
 529 ktr_finish_write_entry(struct ktr_info *info, struct ktr_entry *entry)
 530 {
 531         if (ktr_stacktrace)
 532                 cpu_ktr_caller(entry);
 533 #ifdef KTR_VERBOSE
 534         if (ktr_verbose && info->kf_format) {
 535                 kprintf("cpu%d ", mycpu->gd_cpuid);
 536                 if (ktr_verbose > 1) {
 537                         kprintf("%s.%d\t", entry->ktr_file, entry->ktr_line);
 538                 }
 539                 return !0;
 540         }
 541 #endif
 542         return 0;
 543 }
 544
 545 #ifdef DDB
 546
 547 #define NUM_LINES_PER_PAGE      19
 548
 549 struct tstate {
 550         int     cur;
 551         int     first;
 552 };
 553
 554 static  int db_ktr_verbose;
 555 static  int db_mach_vtrace(int cpu, struct ktr_entry *kp, int idx);
 556
 557 DB_SHOW_COMMAND(ktr, db_ktr_all)
 558 {
 559         struct ktr_cpu_core *kcpu;
 560         int a_flag = 0;
 561         int c;
 562         int nl = 0;
 563         int i;
 564         struct tstate tstate[MAXCPU];
 565         int printcpu = -1;
 566
 567         for(i = 0; i < ncpus; i++) {
 568                 kcpu = &ktr_cpu[i].core;
 569                 tstate[i].first = -1;
 570                 tstate[i].cur = (kcpu->ktr_idx - 1) & ktr_entries_mask;
 571         }
 572         db_ktr_verbose = 0;
 573         while ((c = *(modif++)) != '\0') {
 574                 if (c == 'v') {
 575                         db_ktr_verbose = 1;
 576                 }
 577                 else if (c == 'a') {
 578                         a_flag = 1;
 579                 }
 580                 else if (c == 'c') {
 581                         printcpu = 0;
 582                         while ((c = *(modif++)) != '\0') {
 583                                 if (isdigit(c)) {
 584                                         printcpu *= 10;
 585                                         printcpu += c - '0';
 586                                 }
 587                                 else {
 588                                         modif++;
 589                                         break;
 590                                 }
 591                         }
 592                         modif--;
 593                 }
 594         }
 595         if (printcpu > ncpus - 1) {
 596                 db_printf("Invalid cpu number\n");
 597                 return;
 598         }
 599         /*
 600          * Loop throug all the buffers and print the content of them, sorted
 601          * by the timestamp.
 602          */
 603         while (1) {
 604                 int counter;
 605                 u_int64_t highest_ts;
 606                 struct ktr_entry *kp;
 607                 int highest_cpu;
 608                 int c;
 609
 610                 if (a_flag == 1) {
 611                         c = cncheckc();
 612                         if (c != -1 && c != NOKEY)
 613                                 return;
 614                 }
 615                 highest_ts = 0;
 616                 highest_cpu = -1;
 617                 /*
 618                  * Find the lowest timestamp
 619                  */
 620                 for (i = 0, counter = 0; i < ncpus; i++) {
 621                         kcpu = &ktr_cpu[i].core;
 622                         if (kcpu->ktr_buf == NULL)
 623                                 continue;
 624                         if (printcpu != -1 && printcpu != i)
 625                                 continue;
 626                         if (tstate[i].cur == -1) {
 627                                 counter++;
 628                                 if (counter == ncpus) {
 629                                         db_printf("--- End of trace buffer ---\n");
 630                                         return;
 631                                 }
 632                                 continue;
 633                         }
 634                         if (kcpu->ktr_buf[tstate[i].cur].ktr_timestamp > highest_ts) {
 635                                 highest_ts = kcpu->ktr_buf[tstate[i].cur].ktr_timestamp;
 636                                 highest_cpu = i;
 637                         }
 638                 }
 639                 if (highest_cpu < 0) {
 640                         db_printf("no KTR data available\n");
 641                         break;
 642                 }
 643                 i = highest_cpu;
 644                 kcpu = &ktr_cpu[i].core;
 645                 kp = &kcpu->ktr_buf[tstate[i].cur];
 646                 if (tstate[i].first == -1)
 647                         tstate[i].first = tstate[i].cur;
 648                 if (--tstate[i].cur < 0)
 649                         tstate[i].cur = ktr_entries - 1;
 650                 if (tstate[i].first == tstate[i].cur) {
 651                         db_mach_vtrace(i, kp, tstate[i].cur + 1);
 652                         tstate[i].cur = -1;
 653                         continue;
 654                 }
 655                 if (kcpu->ktr_buf[tstate[i].cur].ktr_info == NULL)
 656                         tstate[i].cur = -1;
 657                 if (db_more(&nl) == -1)
 658                         break;
 659                 if (db_mach_vtrace(i, kp, tstate[i].cur + 1) == 0)
 660                         tstate[i].cur = -1;
 661         }
 662 }
 663
 664 static int
 665 db_mach_vtrace(int cpu, struct ktr_entry *kp, int idx)
 666 {
 667         if (kp->ktr_info == NULL)
 668                 return(0);
 669         db_printf("cpu%d ", cpu);
 670         db_printf("%d: ", idx);
 671         if (db_ktr_verbose) {
 672                 db_printf("%10.10lld %s.%d\t", (long long)kp->ktr_timestamp,
 673                     kp->ktr_file, kp->ktr_line);
 674         }
 675         db_printf("%s\t", kp->ktr_info->kf_name);
 676         db_printf("from(%p,%p) ", kp->ktr_caller1, kp->ktr_caller2);
 677         db_printf("\n");
 678
 679         return(1);
 680 }
 681
 682 #endif  /* DDB */