The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/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  * 3. Neither the name of the author nor the names of any co-contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 
   30 /*
   31  * This module holds the global variables used by KTR and the ktr_tracepoint()
   32  * function that does the actual tracing.
   33  */
   34 
   35 #include <sys/cdefs.h>
   36 __FBSDID("$FreeBSD: releng/9.1/sys/kern/kern_ktr.c 222813 2011-06-07 08:46:13Z attilio $");
   37 
   38 #include "opt_ddb.h"
   39 #include "opt_ktr.h"
   40 #include "opt_alq.h"
   41 
   42 #include <sys/param.h>
   43 #include <sys/queue.h>
   44 #include <sys/alq.h>
   45 #include <sys/cons.h>
   46 #include <sys/cpuset.h>
   47 #include <sys/kernel.h>
   48 #include <sys/ktr.h>
   49 #include <sys/libkern.h>
   50 #include <sys/proc.h>
   51 #include <sys/sysctl.h>
   52 #include <sys/systm.h>
   53 #include <sys/time.h>
   54 
   55 #include <machine/cpu.h>
   56 #ifdef __sparc64__
   57 #include <machine/ktr.h>
   58 #endif
   59 
   60 #ifdef DDB
   61 #include <ddb/ddb.h>
   62 #include <ddb/db_output.h>
   63 #endif
   64 
   65 #ifndef KTR_ENTRIES
   66 #define KTR_ENTRIES     1024
   67 #endif
   68 
   69 #ifndef KTR_MASK
   70 #define KTR_MASK        (0)
   71 #endif
   72 
   73 #ifndef KTR_TIME
   74 #define KTR_TIME        get_cyclecount()
   75 #endif
   76 
   77 #ifndef KTR_CPU
   78 #define KTR_CPU         PCPU_GET(cpuid)
   79 #endif
   80 
   81 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
   82 
   83 SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
   84 
   85 int     ktr_mask = KTR_MASK;
   86 TUNABLE_INT("debug.ktr.mask", &ktr_mask);
   87 SYSCTL_INT(_debug_ktr, OID_AUTO, mask, CTLFLAG_RW,
   88     &ktr_mask, 0, "Bitmask of KTR event classes for which logging is enabled");
   89 
   90 int     ktr_compile = KTR_COMPILE;
   91 SYSCTL_INT(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
   92     &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
   93 
   94 int     ktr_entries = KTR_ENTRIES;
   95 SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD,
   96     &ktr_entries, 0, "Number of entries in the KTR buffer");
   97 
   98 int     ktr_version = KTR_VERSION;
   99 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
  100     &ktr_version, 0, "Version of the KTR interface");
  101 
  102 cpuset_t ktr_cpumask;
  103 static char ktr_cpumask_str[CPUSETBUFSIZ];
  104 TUNABLE_STR("debug.ktr.cpumask", ktr_cpumask_str, sizeof(ktr_cpumask_str));
  105 
  106 static void
  107 ktr_cpumask_initializer(void *dummy __unused)
  108 {
  109 
  110         CPU_FILL(&ktr_cpumask);
  111 #ifdef KTR_CPUMASK
  112         if (cpusetobj_strscan(&ktr_cpumask, KTR_CPUMASK) == -1)
  113                 CPU_FILL(&ktr_cpumask);
  114 #endif
  115 
  116         /*
  117          * TUNABLE_STR() runs with SI_ORDER_MIDDLE priority, thus it must be
  118          * already set, if necessary.
  119          */
  120         if (ktr_cpumask_str[0] != '\0' &&
  121             cpusetobj_strscan(&ktr_cpumask, ktr_cpumask_str) == -1)
  122                 CPU_FILL(&ktr_cpumask);
  123 }
  124 SYSINIT(ktr_cpumask_initializer, SI_SUB_TUNABLES, SI_ORDER_ANY,
  125     ktr_cpumask_initializer, NULL);
  126 
  127 static int
  128 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
  129 {
  130         char lktr_cpumask_str[CPUSETBUFSIZ];
  131         cpuset_t imask;
  132         int error;
  133 
  134         cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
  135         error = sysctl_handle_string(oidp, lktr_cpumask_str,
  136             sizeof(lktr_cpumask_str), req);
  137         if (error != 0 || req->newptr == NULL)
  138                 return (error);
  139         if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
  140                 return (EINVAL);
  141         CPU_COPY(&imask, &ktr_cpumask);
  142 
  143         return (error);
  144 }
  145 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
  146     CTLFLAG_RW | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
  147     sysctl_debug_ktr_cpumask, "S",
  148     "Bitmask of CPUs on which KTR logging is enabled");
  149 
  150 volatile int    ktr_idx = 0;
  151 struct  ktr_entry ktr_buf[KTR_ENTRIES];
  152 
  153 static int
  154 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
  155 {
  156         int clear, error;
  157 
  158         clear = 0;
  159         error = sysctl_handle_int(oidp, &clear, 0, req);
  160         if (error || !req->newptr)
  161                 return (error);
  162 
  163         if (clear) {
  164                 bzero(ktr_buf, sizeof(ktr_buf));
  165                 ktr_idx = 0;
  166         }
  167 
  168         return (error);
  169 }
  170 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
  171     sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
  172 
  173 #ifdef KTR_VERBOSE
  174 int     ktr_verbose = KTR_VERBOSE;
  175 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
  176 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
  177 #endif
  178 
  179 #ifdef KTR_ALQ
  180 struct alq *ktr_alq;
  181 char    ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
  182 int     ktr_alq_cnt = 0;
  183 int     ktr_alq_depth = KTR_ENTRIES;
  184 int     ktr_alq_enabled = 0;
  185 int     ktr_alq_failed = 0;
  186 int     ktr_alq_max = 0;
  187 
  188 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
  189     "Maximum number of entries to write");
  190 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
  191     "Current number of written entries");
  192 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
  193     "Number of times we overran the buffer");
  194 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
  195     "Number of items in the write buffer");
  196 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
  197     sizeof(ktr_alq_file), "KTR logging file");
  198 
  199 static int
  200 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
  201 {
  202         int error;
  203         int enable;
  204 
  205         enable = ktr_alq_enabled;
  206 
  207         error = sysctl_handle_int(oidp, &enable, 0, req);
  208         if (error || !req->newptr)
  209                 return (error);
  210 
  211         if (enable) {
  212                 if (ktr_alq_enabled)
  213                         return (0);
  214                 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
  215                     req->td->td_ucred, ALQ_DEFAULT_CMODE,
  216                     sizeof(struct ktr_entry), ktr_alq_depth);
  217                 if (error == 0) {
  218                         ktr_alq_cnt = 0;
  219                         ktr_alq_failed = 0;
  220                         ktr_alq_enabled = 1;
  221                 }
  222         } else {
  223                 if (ktr_alq_enabled == 0)
  224                         return (0);
  225                 ktr_alq_enabled = 0;
  226                 alq_close(ktr_alq);
  227                 ktr_alq = NULL;
  228         }
  229 
  230         return (error);
  231 }
  232 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
  233     CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
  234     "I", "Enable KTR logging");
  235 #endif
  236 
  237 void
  238 ktr_tracepoint(u_int mask, const char *file, int line, const char *format,
  239     u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
  240     u_long arg6)
  241 {
  242         struct ktr_entry *entry;
  243 #ifdef KTR_ALQ
  244         struct ale *ale = NULL;
  245 #endif
  246         int newindex, saveindex;
  247 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  248         struct thread *td;
  249 #endif
  250         int cpu;
  251 
  252         if (panicstr)
  253                 return;
  254         if ((ktr_mask & mask) == 0)
  255                 return;
  256         cpu = KTR_CPU;
  257         if (!CPU_ISSET(cpu, &ktr_cpumask))
  258                 return;
  259 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  260         td = curthread;
  261         if (td->td_pflags & TDP_INKTR)
  262                 return;
  263         td->td_pflags |= TDP_INKTR;
  264 #endif
  265 #ifdef KTR_ALQ
  266         if (ktr_alq_enabled) {
  267                 if (td->td_critnest == 0 &&
  268                     (td->td_flags & TDF_IDLETD) == 0 &&
  269                     td != ald_thread) {
  270                         if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
  271                                 goto done;
  272                         if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
  273                                 ktr_alq_failed++;
  274                                 goto done;
  275                         }
  276                         ktr_alq_cnt++;
  277                         entry = (struct ktr_entry *)ale->ae_data;
  278                 } else {
  279                         goto done;
  280                 }
  281         } else
  282 #endif
  283         {
  284                 do {
  285                         saveindex = ktr_idx;
  286                         newindex = (saveindex + 1) & (KTR_ENTRIES - 1);
  287                 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
  288                 entry = &ktr_buf[saveindex];
  289         }
  290         entry->ktr_timestamp = KTR_TIME;
  291         entry->ktr_cpu = cpu;
  292         entry->ktr_thread = curthread;
  293         if (file != NULL)
  294                 while (strncmp(file, "../", 3) == 0)
  295                         file += 3;
  296         entry->ktr_file = file;
  297         entry->ktr_line = line;
  298 #ifdef KTR_VERBOSE
  299         if (ktr_verbose) {
  300 #ifdef SMP
  301                 printf("cpu%d ", cpu);
  302 #endif
  303                 if (ktr_verbose > 1) {
  304                         printf("%s.%d\t", entry->ktr_file,
  305                             entry->ktr_line);
  306                 }
  307                 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
  308                 printf("\n");
  309         }
  310 #endif
  311         entry->ktr_desc = format;
  312         entry->ktr_parms[0] = arg1;
  313         entry->ktr_parms[1] = arg2;
  314         entry->ktr_parms[2] = arg3;
  315         entry->ktr_parms[3] = arg4;
  316         entry->ktr_parms[4] = arg5;
  317         entry->ktr_parms[5] = arg6;
  318 #ifdef KTR_ALQ
  319         if (ktr_alq_enabled && ale)
  320                 alq_post(ktr_alq, ale);
  321 done:
  322 #endif
  323 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  324         td->td_pflags &= ~TDP_INKTR;
  325 #endif
  326 }
  327 
  328 #ifdef DDB
  329 
  330 struct tstate {
  331         int     cur;
  332         int     first;
  333 };
  334 static  struct tstate tstate;
  335 static  int db_ktr_verbose;
  336 static  int db_mach_vtrace(void);
  337 
  338 DB_SHOW_COMMAND(ktr, db_ktr_all)
  339 {
  340         
  341         tstate.cur = (ktr_idx - 1) & (KTR_ENTRIES - 1);
  342         tstate.first = -1;
  343         db_ktr_verbose = 0;
  344         db_ktr_verbose |= (index(modif, 'v') != NULL) ? 2 : 0;
  345         db_ktr_verbose |= (index(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
  346         if (index(modif, 'a') != NULL) {
  347                 db_disable_pager();
  348                 while (cncheckc() != -1)
  349                         if (db_mach_vtrace() == 0)
  350                                 break;
  351         } else {
  352                 while (!db_pager_quit)
  353                         if (db_mach_vtrace() == 0)
  354                                 break;
  355         }
  356 }
  357 
  358 static int
  359 db_mach_vtrace(void)
  360 {
  361         struct ktr_entry        *kp;
  362 
  363         if (tstate.cur == tstate.first) {
  364                 db_printf("--- End of trace buffer ---\n");
  365                 return (0);
  366         }
  367         kp = &ktr_buf[tstate.cur];
  368 
  369         /* Skip over unused entries. */
  370         if (kp->ktr_desc == NULL) {
  371                 db_printf("--- End of trace buffer ---\n");
  372                 return (0);
  373         }
  374         db_printf("%d (%p", tstate.cur, kp->ktr_thread);
  375 #ifdef SMP
  376         db_printf(":cpu%d", kp->ktr_cpu);
  377 #endif
  378         db_printf(")");
  379         if (db_ktr_verbose >= 1) {
  380                 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
  381         }
  382         if (db_ktr_verbose >= 2) {
  383                 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
  384         }
  385         db_printf(": ");
  386         db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
  387             kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
  388             kp->ktr_parms[5]);
  389         db_printf("\n");
  390 
  391         if (tstate.first == -1)
  392                 tstate.first = tstate.cur;
  393 
  394         if (--tstate.cur < 0)
  395                 tstate.cur = KTR_ENTRIES - 1;
  396 
  397         return (1);
  398 }
  399 
  400 #endif  /* DDB */

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