kern_ktr.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org>
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   25  * SUCH DAMAGE.
   26  */
   27 
   28 /*
   29  * This module holds the global variables used by KTR and the ktr_tracepoint()
   30  * function that does the actual tracing.
   31  */
   32 
   33 #include <sys/cdefs.h>
   34 __FBSDID("$FreeBSD$");
   35 
   36 #include "opt_ddb.h"
   37 #include "opt_ktr.h"
   38 #include "opt_alq.h"
   39 
   40 #include <sys/param.h>
   41 #include <sys/queue.h>
   42 #include <sys/alq.h>
   43 #include <sys/cons.h>
   44 #include <sys/cpuset.h>
   45 #include <sys/kdb.h>
   46 #include <sys/kernel.h>
   47 #include <sys/ktr.h>
   48 #include <sys/libkern.h>
   49 #include <sys/lock.h>
   50 #include <sys/malloc.h>
   51 #include <sys/mutex.h>
   52 #include <sys/proc.h>
   53 #include <sys/smp.h>
   54 #include <sys/sysctl.h>
   55 #include <sys/systm.h>
   56 #include <sys/time.h>
   57 
   58 #include <machine/cpu.h>
   59 
   60 #ifdef DDB
   61 #include <ddb/ddb.h>
   62 #include <ddb/db_output.h>
   63 #endif
   64 
   65 #ifndef KTR_BOOT_ENTRIES
   66 #define KTR_BOOT_ENTRIES        1024
   67 #endif
   68 
   69 #ifndef KTR_ENTRIES
   70 #define KTR_ENTRIES     1024
   71 #endif
   72 
   73 /* Limit the allocations to something manageable. */
   74 #define KTR_ENTRIES_MAX (8 * 1024 * 1024)
   75 
   76 #ifndef KTR_MASK
   77 #define KTR_MASK        (0)
   78 #endif
   79 
   80 #ifndef KTR_CPUMASK
   81 #define KTR_CPUMASK     CPUSET_FSET
   82 #endif
   83 
   84 #ifndef KTR_TIME
   85 #define KTR_TIME        get_cyclecount()
   86 #endif
   87 
   88 #ifndef KTR_CPU
   89 #define KTR_CPU         PCPU_GET(cpuid)
   90 #endif
   91 
   92 static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
   93 
   94 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
   95 
   96 volatile int    ktr_idx = 0;
   97 uint64_t ktr_mask = KTR_MASK;
   98 uint64_t ktr_compile = KTR_COMPILE;
   99 int     ktr_entries = KTR_BOOT_ENTRIES;
  100 int     ktr_version = KTR_VERSION;
  101 struct  ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
  102 struct  ktr_entry *ktr_buf = ktr_buf_init;
  103 cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
  104 
  105 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
  106 
  107 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
  108     &ktr_version, 0, "Version of the KTR interface");
  109 
  110 SYSCTL_UQUAD(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
  111     &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
  112 
  113 static int
  114 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
  115 {
  116         char lktr_cpumask_str[CPUSETBUFSIZ];
  117         cpuset_t imask;
  118         int error;
  119 
  120         cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
  121         error = sysctl_handle_string(oidp, lktr_cpumask_str,
  122             sizeof(lktr_cpumask_str), req);
  123         if (error != 0 || req->newptr == NULL)
  124                 return (error);
  125         if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
  126                 return (EINVAL);
  127         CPU_COPY(&imask, &ktr_cpumask);
  128 
  129         return (error);
  130 }
  131 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
  132     CTLFLAG_RWTUN | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
  133     sysctl_debug_ktr_cpumask, "S",
  134     "Bitmask of CPUs on which KTR logging is enabled");
  135 
  136 static int
  137 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
  138 {
  139         int clear, error;
  140 
  141         clear = 0;
  142         error = sysctl_handle_int(oidp, &clear, 0, req);
  143         if (error || !req->newptr)
  144                 return (error);
  145 
  146         if (clear) {
  147                 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
  148                 ktr_idx = 0;
  149         }
  150 
  151         return (error);
  152 }
  153 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
  154     sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
  155 
  156 /*
  157  * This is a sysctl proc so that it is serialized as !MPSAFE along with
  158  * the other ktr sysctl procs.
  159  */
  160 static int
  161 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
  162 {
  163         uint64_t mask;
  164         int error;
  165 
  166         mask = ktr_mask;
  167         error = sysctl_handle_64(oidp, &mask, 0, req);
  168         if (error || !req->newptr)
  169                 return (error);
  170         ktr_mask = mask;
  171         return (error);
  172 }
  173 
  174 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_U64 | CTLFLAG_RWTUN, 0, 0,
  175     sysctl_debug_ktr_mask, "QU",
  176     "Bitmask of KTR event classes for which logging is enabled");
  177 
  178 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
  179 /*
  180  * A simplified version of sysctl_debug_ktr_entries.
  181  * No need to care about SMP, scheduling, etc.
  182  */
  183 static void
  184 ktr_entries_initializer(void *dummy __unused)
  185 {
  186         uint64_t mask;
  187 
  188         /* Temporarily disable ktr in case malloc() is being traced. */
  189         mask = ktr_mask;
  190         ktr_mask = 0;
  191         ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
  192             M_WAITOK | M_ZERO);
  193         memcpy(ktr_buf, ktr_buf_init + ktr_idx,
  194             (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
  195         if (ktr_idx != 0) {
  196                 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
  197                     ktr_idx * sizeof(*ktr_buf));
  198                 ktr_idx = KTR_BOOT_ENTRIES;
  199         }
  200         ktr_entries = KTR_ENTRIES;
  201         ktr_mask = mask;
  202 }
  203 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
  204     ktr_entries_initializer, NULL);
  205 #endif
  206 
  207 static int
  208 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
  209 {
  210         uint64_t mask;
  211         int entries, error;
  212         struct ktr_entry *buf, *oldbuf;
  213 
  214         entries = ktr_entries;
  215         error = sysctl_handle_int(oidp, &entries, 0, req);
  216         if (error || !req->newptr)
  217                 return (error);
  218         if (entries > KTR_ENTRIES_MAX)
  219                 return (ERANGE);
  220         /* Disable ktr temporarily. */
  221         mask = ktr_mask;
  222         ktr_mask = 0;
  223         /* Wait for threads to go idle. */
  224         if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
  225                 ktr_mask = mask;
  226                 return (error);
  227         }
  228         if (ktr_buf != ktr_buf_init)
  229                 oldbuf = ktr_buf;
  230         else
  231                 oldbuf = NULL;
  232         /* Allocate a new buffer. */
  233         buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
  234         /* Install the new buffer and restart ktr. */
  235         ktr_buf = buf;
  236         ktr_entries = entries;
  237         ktr_idx = 0;
  238         ktr_mask = mask;
  239         if (oldbuf != NULL)
  240                 free(oldbuf, M_KTR);
  241 
  242         return (error);
  243 }
  244 
  245 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
  246     sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
  247 
  248 #ifdef KTR_VERBOSE
  249 int     ktr_verbose = KTR_VERBOSE;
  250 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
  251 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
  252 #endif
  253 
  254 #ifdef KTR_ALQ
  255 struct alq *ktr_alq;
  256 char    ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
  257 int     ktr_alq_cnt = 0;
  258 int     ktr_alq_depth = KTR_ENTRIES;
  259 int     ktr_alq_enabled = 0;
  260 int     ktr_alq_failed = 0;
  261 int     ktr_alq_max = 0;
  262 
  263 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
  264     "Maximum number of entries to write");
  265 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
  266     "Current number of written entries");
  267 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
  268     "Number of times we overran the buffer");
  269 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
  270     "Number of items in the write buffer");
  271 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
  272     sizeof(ktr_alq_file), "KTR logging file");
  273 
  274 static int
  275 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
  276 {
  277         int error;
  278         int enable;
  279 
  280         enable = ktr_alq_enabled;
  281 
  282         error = sysctl_handle_int(oidp, &enable, 0, req);
  283         if (error || !req->newptr)
  284                 return (error);
  285 
  286         if (enable) {
  287                 if (ktr_alq_enabled)
  288                         return (0);
  289                 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
  290                     req->td->td_ucred, ALQ_DEFAULT_CMODE,
  291                     sizeof(struct ktr_entry), ktr_alq_depth);
  292                 if (error == 0) {
  293                         ktr_alq_cnt = 0;
  294                         ktr_alq_failed = 0;
  295                         ktr_alq_enabled = 1;
  296                 }
  297         } else {
  298                 if (ktr_alq_enabled == 0)
  299                         return (0);
  300                 ktr_alq_enabled = 0;
  301                 alq_close(ktr_alq);
  302                 ktr_alq = NULL;
  303         }
  304 
  305         return (error);
  306 }
  307 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
  308     CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
  309     "I", "Enable KTR logging");
  310 #endif
  311 
  312 void
  313 ktr_tracepoint(uint64_t mask, const char *file, int line, const char *format,
  314     u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
  315     u_long arg6)
  316 {
  317         struct ktr_entry *entry;
  318 #ifdef KTR_ALQ
  319         struct ale *ale = NULL;
  320 #endif
  321         int newindex, saveindex;
  322 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  323         struct thread *td;
  324 #endif
  325         int cpu;
  326 
  327         if (panicstr || kdb_active)
  328                 return;
  329         if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
  330                 return;
  331         cpu = KTR_CPU;
  332         if (!CPU_ISSET(cpu, &ktr_cpumask))
  333                 return;
  334 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  335         td = curthread;
  336         if (td->td_pflags & TDP_INKTR)
  337                 return;
  338         td->td_pflags |= TDP_INKTR;
  339 #endif
  340 #ifdef KTR_ALQ
  341         if (ktr_alq_enabled) {
  342                 if (td->td_critnest == 0 &&
  343                     (TD_IS_IDLETHREAD(td)) == 0 &&
  344                     td != ald_thread) {
  345                         if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
  346                                 goto done;
  347                         if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
  348                                 ktr_alq_failed++;
  349                                 goto done;
  350                         }
  351                         ktr_alq_cnt++;
  352                         entry = (struct ktr_entry *)ale->ae_data;
  353                 } else {
  354                         goto done;
  355                 }
  356         } else
  357 #endif
  358         {
  359                 do {
  360                         saveindex = ktr_idx;
  361                         newindex = (saveindex + 1) % ktr_entries;
  362                 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
  363                 entry = &ktr_buf[saveindex];
  364         }
  365         entry->ktr_timestamp = KTR_TIME;
  366         entry->ktr_cpu = cpu;
  367         entry->ktr_thread = curthread;
  368         if (file != NULL)
  369                 while (strncmp(file, "../", 3) == 0)
  370                         file += 3;
  371         entry->ktr_file = file;
  372         entry->ktr_line = line;
  373 #ifdef KTR_VERBOSE
  374         if (ktr_verbose) {
  375 #ifdef SMP
  376                 printf("cpu%d ", cpu);
  377 #endif
  378                 if (ktr_verbose > 1) {
  379                         printf("%s.%d\t", entry->ktr_file,
  380                             entry->ktr_line);
  381                 }
  382                 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
  383                 printf("\n");
  384         }
  385 #endif
  386         entry->ktr_desc = format;
  387         entry->ktr_parms[0] = arg1;
  388         entry->ktr_parms[1] = arg2;
  389         entry->ktr_parms[2] = arg3;
  390         entry->ktr_parms[3] = arg4;
  391         entry->ktr_parms[4] = arg5;
  392         entry->ktr_parms[5] = arg6;
  393 #ifdef KTR_ALQ
  394         if (ktr_alq_enabled && ale)
  395                 alq_post(ktr_alq, ale);
  396 done:
  397 #endif
  398 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  399         td->td_pflags &= ~TDP_INKTR;
  400 #endif
  401 }
  402 
  403 #ifdef DDB
  404 
  405 struct tstate {
  406         int     cur;
  407         int     first;
  408 };
  409 static  struct tstate tstate;
  410 static  int db_ktr_verbose;
  411 static  int db_mach_vtrace(void);
  412 
  413 DB_SHOW_COMMAND(ktr, db_ktr_all)
  414 {
  415         
  416         tstate.cur = (ktr_idx - 1) % ktr_entries;
  417         tstate.first = -1;
  418         db_ktr_verbose = 0;
  419         db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
  420         db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestamp please */
  421         if (strchr(modif, 'a') != NULL) {
  422                 db_disable_pager();
  423                 while (cncheckc() == -1)
  424                         if (db_mach_vtrace() == 0)
  425                                 break;
  426         } else {
  427                 while (!db_pager_quit)
  428                         if (db_mach_vtrace() == 0)
  429                                 break;
  430         }
  431 }
  432 
  433 static int
  434 db_mach_vtrace(void)
  435 {
  436         struct ktr_entry        *kp;
  437 
  438         if (tstate.cur == tstate.first || ktr_buf == NULL) {
  439                 db_printf("--- End of trace buffer ---\n");
  440                 return (0);
  441         }
  442         kp = &ktr_buf[tstate.cur];
  443 
  444         /* Skip over unused entries. */
  445         if (kp->ktr_desc == NULL) {
  446                 db_printf("--- End of trace buffer ---\n");
  447                 return (0);
  448         }
  449         db_printf("%d (%p", tstate.cur, kp->ktr_thread);
  450 #ifdef SMP
  451         db_printf(":cpu%d", kp->ktr_cpu);
  452 #endif
  453         db_printf(")");
  454         if (db_ktr_verbose >= 1) {
  455                 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
  456         }
  457         if (db_ktr_verbose >= 2) {
  458                 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
  459         }
  460         db_printf(": ");
  461         db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
  462             kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
  463             kp->ktr_parms[5]);
  464         db_printf("\n");
  465 
  466         if (tstate.first == -1)
  467                 tstate.first = tstate.cur;
  468 
  469         if (--tstate.cur < 0)
  470                 tstate.cur = ktr_entries - 1;
  471 
  472         return (1);
  473 }
  474 
  475 #endif  /* DDB */
Cache object: e00bfc4b127f2bf11b5069a6f20472f5
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_ktr.c

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