kern_ktr.c

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    1 /*-
    2  * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 /*
   28  * This module holds the global variables used by KTR and the ktr_tracepoint()
   29  * function that does the actual tracing.
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/10.1/sys/kern/kern_ktr.c 262192 2014-02-18 20:27:17Z jhb $");
   34 
   35 #include "opt_ddb.h"
   36 #include "opt_ktr.h"
   37 #include "opt_alq.h"
   38 
   39 #include <sys/param.h>
   40 #include <sys/queue.h>
   41 #include <sys/alq.h>
   42 #include <sys/cons.h>
   43 #include <sys/cpuset.h>
   44 #include <sys/kernel.h>
   45 #include <sys/ktr.h>
   46 #include <sys/libkern.h>
   47 #include <sys/lock.h>
   48 #include <sys/malloc.h>
   49 #include <sys/mutex.h>
   50 #include <sys/proc.h>
   51 #include <sys/smp.h>
   52 #include <sys/sysctl.h>
   53 #include <sys/systm.h>
   54 #include <sys/time.h>
   55 
   56 #include <machine/cpu.h>
   57 #ifdef __sparc64__
   58 #include <machine/ktr.h>
   59 #endif
   60 
   61 #ifdef DDB
   62 #include <ddb/ddb.h>
   63 #include <ddb/db_output.h>
   64 #endif
   65 
   66 #ifndef KTR_BOOT_ENTRIES
   67 #define KTR_BOOT_ENTRIES        1024
   68 #endif
   69 
   70 #ifndef KTR_ENTRIES
   71 #define KTR_ENTRIES     1024
   72 #endif
   73 
   74 /* Limit the allocations to something manageable. */
   75 #define KTR_ENTRIES_MAX (8 * 1024 * 1024)
   76 
   77 #ifndef KTR_MASK
   78 #define KTR_MASK        (0)
   79 #endif
   80 
   81 #ifndef KTR_CPUMASK
   82 #define KTR_CPUMASK     CPUSET_FSET
   83 #endif
   84 
   85 #ifndef KTR_TIME
   86 #define KTR_TIME        get_cyclecount()
   87 #endif
   88 
   89 #ifndef KTR_CPU
   90 #define KTR_CPU         PCPU_GET(cpuid)
   91 #endif
   92 
   93 static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
   94 
   95 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
   96 
   97 volatile int    ktr_idx = 0;
   98 int     ktr_mask = KTR_MASK;
   99 int     ktr_compile = KTR_COMPILE;
  100 int     ktr_entries = KTR_BOOT_ENTRIES;
  101 int     ktr_version = KTR_VERSION;
  102 struct  ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
  103 struct  ktr_entry *ktr_buf = ktr_buf_init;
  104 cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
  105 static char ktr_cpumask_str[CPUSETBUFSIZ];
  106 
  107 TUNABLE_INT("debug.ktr.mask", &ktr_mask);
  108 
  109 TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
  110 
  111 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
  112 
  113 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
  114     &ktr_version, 0, "Version of the KTR interface");
  115 
  116 SYSCTL_UINT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
  117     &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
  118 
  119 static void
  120 ktr_cpumask_initializer(void *dummy __unused)
  121 {
  122 
  123         /*
  124          * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
  125          * already set, if necessary.
  126          */
  127         if (ktr_cpumask_str[0] != '\0' &&
  128             cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
  129                 CPU_FILL(&ktr_cpumask);
  130 }
  131 SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
  132     ktr_cpumask_initializer, NULL);
  133 
  134 static int
  135 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
  136 {
  137         char lktr_cpumask_str[CPUSETBUFSIZ];
  138         cpuset_t imask;
  139         int error;
  140 
  141         cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
  142         error = sysctl_handle_string(oidp, lktr_cpumask_str,
  143             sizeof(lktr_cpumask_str), req);
  144         if (error != 0 || req->newptr == NULL)
  145                 return (error);
  146         if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
  147                 return (EINVAL);
  148         CPU_COPY(&imask, &ktr_cpumask);
  149 
  150         return (error);
  151 }
  152 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
  153     CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
  154     sysctl_debug_ktr_cpumask, "S",
  155     "Bitmask of CPUs on which KTR logging is enabled");
  156 
  157 static int
  158 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
  159 {
  160         int clear, error;
  161 
  162         clear = 0;
  163         error = sysctl_handle_int(oidp, &clear, 0, req);
  164         if (error || !req->newptr)
  165                 return (error);
  166 
  167         if (clear) {
  168                 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
  169                 ktr_idx = 0;
  170         }
  171 
  172         return (error);
  173 }
  174 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
  175     sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
  176 
  177 /*
  178  * This is a sysctl proc so that it is serialized as !MPSAFE along with
  179  * the other ktr sysctl procs.
  180  */
  181 static int
  182 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
  183 {
  184         int mask, error;
  185 
  186         mask = ktr_mask;
  187         error = sysctl_handle_int(oidp, &mask, 0, req);
  188         if (error || !req->newptr)
  189                 return (error);
  190         ktr_mask = mask;
  191         return (error);
  192 }
  193 
  194 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_UINT|CTLFLAG_RW, 0, 0,
  195     sysctl_debug_ktr_mask, "IU",
  196     "Bitmask of KTR event classes for which logging is enabled");
  197 
  198 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
  199 /*
  200  * A simplified version of sysctl_debug_ktr_entries.
  201  * No need to care about SMP, scheduling, etc.
  202  */
  203 static void
  204 ktr_entries_initializer(void *dummy __unused)
  205 {
  206         int mask;
  207 
  208         /* Temporarily disable ktr in case malloc() is being traced. */
  209         mask = ktr_mask;
  210         ktr_mask = 0;
  211         ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
  212             M_WAITOK | M_ZERO);
  213         memcpy(ktr_buf, ktr_buf_init + ktr_idx,
  214             (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
  215         if (ktr_idx != 0)
  216                 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
  217                     ktr_idx * sizeof(*ktr_buf));
  218         ktr_entries = KTR_ENTRIES;
  219         ktr_mask = mask;
  220 }
  221 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
  222     ktr_entries_initializer, NULL);
  223 #endif
  224 
  225 static int
  226 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
  227 {
  228         int entries, error, mask;
  229         struct ktr_entry *buf, *oldbuf;
  230 
  231         entries = ktr_entries;
  232         error = sysctl_handle_int(oidp, &entries, 0, req);
  233         if (error || !req->newptr)
  234                 return (error);
  235         if (entries > KTR_ENTRIES_MAX)
  236                 return (ERANGE);
  237         /* Disable ktr temporarily. */
  238         mask = ktr_mask;
  239         atomic_store_rel_int(&ktr_mask, 0);
  240         /* Wait for threads to go idle. */
  241         if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
  242                 ktr_mask = mask;
  243                 return (error);
  244         }
  245         if (ktr_buf != ktr_buf_init)
  246                 oldbuf = ktr_buf;
  247         else
  248                 oldbuf = NULL;
  249         /* Allocate a new buffer. */
  250         buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
  251         /* Install the new buffer and restart ktr. */
  252         ktr_buf = buf;
  253         ktr_entries = entries;
  254         ktr_idx = 0;
  255         atomic_store_rel_int(&ktr_mask, mask);
  256         if (oldbuf != NULL)
  257                 free(oldbuf, M_KTR);
  258 
  259         return (error);
  260 }
  261 
  262 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
  263     sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
  264 
  265 #ifdef KTR_VERBOSE
  266 int     ktr_verbose = KTR_VERBOSE;
  267 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
  268 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
  269 #endif
  270 
  271 #ifdef KTR_ALQ
  272 struct alq *ktr_alq;
  273 char    ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
  274 int     ktr_alq_cnt = 0;
  275 int     ktr_alq_depth = KTR_ENTRIES;
  276 int     ktr_alq_enabled = 0;
  277 int     ktr_alq_failed = 0;
  278 int     ktr_alq_max = 0;
  279 
  280 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
  281     "Maximum number of entries to write");
  282 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
  283     "Current number of written entries");
  284 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
  285     "Number of times we overran the buffer");
  286 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
  287     "Number of items in the write buffer");
  288 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
  289     sizeof(ktr_alq_file), "KTR logging file");
  290 
  291 static int
  292 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
  293 {
  294         int error;
  295         int enable;
  296 
  297         enable = ktr_alq_enabled;
  298 
  299         error = sysctl_handle_int(oidp, &enable, 0, req);
  300         if (error || !req->newptr)
  301                 return (error);
  302 
  303         if (enable) {
  304                 if (ktr_alq_enabled)
  305                         return (0);
  306                 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
  307                     req->td->td_ucred, ALQ_DEFAULT_CMODE,
  308                     sizeof(struct ktr_entry), ktr_alq_depth);
  309                 if (error == 0) {
  310                         ktr_alq_cnt = 0;
  311                         ktr_alq_failed = 0;
  312                         ktr_alq_enabled = 1;
  313                 }
  314         } else {
  315                 if (ktr_alq_enabled == 0)
  316                         return (0);
  317                 ktr_alq_enabled = 0;
  318                 alq_close(ktr_alq);
  319                 ktr_alq = NULL;
  320         }
  321 
  322         return (error);
  323 }
  324 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
  325     CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
  326     "I", "Enable KTR logging");
  327 #endif
  328 
  329 void
  330 ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
  331     u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
  332     u_long arg6)
  333 {
  334         struct ktr_entry *entry;
  335 #ifdef KTR_ALQ
  336         struct ale *ale = NULL;
  337 #endif
  338         int newindex, saveindex;
  339 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  340         struct thread *td;
  341 #endif
  342         int cpu;
  343 
  344         if (panicstr)
  345                 return;
  346         if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
  347                 return;
  348         cpu = KTR_CPU;
  349         if (!CPU_ISSET(cpu, &ktr_cpumask))
  350                 return;
  351 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  352         td = curthread;
  353         if (td->td_pflags & TDP_INKTR)
  354                 return;
  355         td->td_pflags |= TDP_INKTR;
  356 #endif
  357 #ifdef KTR_ALQ
  358         if (ktr_alq_enabled) {
  359                 if (td->td_critnest == 0 &&
  360                     (td->td_flags & TDF_IDLETD) == 0 &&
  361                     td != ald_thread) {
  362                         if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
  363                                 goto done;
  364                         if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
  365                                 ktr_alq_failed++;
  366                                 goto done;
  367                         }
  368                         ktr_alq_cnt++;
  369                         entry = (struct ktr_entry *)ale->ae_data;
  370                 } else {
  371                         goto done;
  372                 }
  373         } else
  374 #endif
  375         {
  376                 do {
  377                         saveindex = ktr_idx;
  378                         newindex = (saveindex + 1) % ktr_entries;
  379                 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
  380                 entry = &ktr_buf[saveindex];
  381         }
  382         entry->ktr_timestamp = KTR_TIME;
  383         entry->ktr_cpu = cpu;
  384         entry->ktr_thread = curthread;
  385         if (file != NULL)
  386                 while (strncmp(file, "../", 3) == 0)
  387                         file += 3;
  388         entry->ktr_file = file;
  389         entry->ktr_line = line;
  390 #ifdef KTR_VERBOSE
  391         if (ktr_verbose) {
  392 #ifdef SMP
  393                 printf("cpu%d ", cpu);
  394 #endif
  395                 if (ktr_verbose > 1) {
  396                         printf("%s.%d\t", entry->ktr_file,
  397                             entry->ktr_line);
  398                 }
  399                 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
  400                 printf("\n");
  401         }
  402 #endif
  403         entry->ktr_desc = format;
  404         entry->ktr_parms[0] = arg1;
  405         entry->ktr_parms[1] = arg2;
  406         entry->ktr_parms[2] = arg3;
  407         entry->ktr_parms[3] = arg4;
  408         entry->ktr_parms[4] = arg5;
  409         entry->ktr_parms[5] = arg6;
  410 #ifdef KTR_ALQ
  411         if (ktr_alq_enabled && ale)
  412                 alq_post(ktr_alq, ale);
  413 done:
  414 #endif
  415 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  416         td->td_pflags &= ~TDP_INKTR;
  417 #endif
  418 }
  419 
  420 #ifdef DDB
  421 
  422 struct tstate {
  423         int     cur;
  424         int     first;
  425 };
  426 static  struct tstate tstate;
  427 static  int db_ktr_verbose;
  428 static  int db_mach_vtrace(void);
  429 
  430 DB_SHOW_COMMAND(ktr, db_ktr_all)
  431 {
  432         
  433         tstate.cur = (ktr_idx - 1) % ktr_entries;
  434         tstate.first = -1;
  435         db_ktr_verbose = 0;
  436         db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
  437         db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
  438         if (strchr(modif, 'a') != NULL) {
  439                 db_disable_pager();
  440                 while (cncheckc() != -1)
  441                         if (db_mach_vtrace() == 0)
  442                                 break;
  443         } else {
  444                 while (!db_pager_quit)
  445                         if (db_mach_vtrace() == 0)
  446                                 break;
  447         }
  448 }
  449 
  450 static int
  451 db_mach_vtrace(void)
  452 {
  453         struct ktr_entry        *kp;
  454 
  455         if (tstate.cur == tstate.first || ktr_buf == NULL) {
  456                 db_printf("--- End of trace buffer ---\n");
  457                 return (0);
  458         }
  459         kp = &ktr_buf[tstate.cur];
  460 
  461         /* Skip over unused entries. */
  462         if (kp->ktr_desc == NULL) {
  463                 db_printf("--- End of trace buffer ---\n");
  464                 return (0);
  465         }
  466         db_printf("%d (%p", tstate.cur, kp->ktr_thread);
  467 #ifdef SMP
  468         db_printf(":cpu%d", kp->ktr_cpu);
  469 #endif
  470         db_printf(")");
  471         if (db_ktr_verbose >= 1) {
  472                 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
  473         }
  474         if (db_ktr_verbose >= 2) {
  475                 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
  476         }
  477         db_printf(": ");
  478         db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
  479             kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
  480             kp->ktr_parms[5]);
  481         db_printf("\n");
  482 
  483         if (tstate.first == -1)
  484                 tstate.first = tstate.cur;
  485 
  486         if (--tstate.cur < 0)
  487                 tstate.cur = ktr_entries - 1;
  488 
  489         return (1);
  490 }
  491 
  492 #endif  /* DDB */
Cache object: e1244e1e4a192155635abcc1c6f6e712
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_ktr.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_ktr.c
