kern_ktr.c

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    1 /*-
    2  * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org>
    3  *
    4  * Redistribution and use in source and binary forms, with or without
    5  * modification, are permitted provided that the following conditions
    6  * are met:
    7  * 1. Redistributions of source code must retain the above copyright
    8  *    notice, this list of conditions and the following disclaimer.
    9  * 2. Redistributions in binary form must reproduce the above copyright
   10  *    notice, this list of conditions and the following disclaimer in the
   11  *    documentation and/or other materials provided with the distribution.
   12  *
   13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   23  * SUCH DAMAGE.
   24  */
   25 
   26 /*
   27  * This module holds the global variables used by KTR and the ktr_tracepoint()
   28  * function that does the actual tracing.
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD$");
   33 
   34 #include "opt_ddb.h"
   35 #include "opt_ktr.h"
   36 #include "opt_alq.h"
   37 
   38 #include <sys/param.h>
   39 #include <sys/queue.h>
   40 #include <sys/alq.h>
   41 #include <sys/cons.h>
   42 #include <sys/cpuset.h>
   43 #include <sys/kdb.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 
   58 #ifdef DDB
   59 #include <ddb/ddb.h>
   60 #include <ddb/db_output.h>
   61 #endif
   62 
   63 #ifndef KTR_BOOT_ENTRIES
   64 #define KTR_BOOT_ENTRIES        1024
   65 #endif
   66 
   67 #ifndef KTR_ENTRIES
   68 #define KTR_ENTRIES     1024
   69 #endif
   70 
   71 /* Limit the allocations to something manageable. */
   72 #define KTR_ENTRIES_MAX (8 * 1024 * 1024)
   73 
   74 #ifndef KTR_MASK
   75 #define KTR_MASK        (0)
   76 #endif
   77 
   78 #ifndef KTR_CPUMASK
   79 #define KTR_CPUMASK     CPUSET_FSET
   80 #endif
   81 
   82 #ifndef KTR_TIME
   83 #define KTR_TIME        get_cyclecount()
   84 #endif
   85 
   86 #ifndef KTR_CPU
   87 #define KTR_CPU         PCPU_GET(cpuid)
   88 #endif
   89 
   90 static MALLOC_DEFINE(M_KTR, "KTR", "KTR");
   91 
   92 FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
   93 
   94 volatile int    ktr_idx = 0;
   95 uint64_t ktr_mask = KTR_MASK;
   96 uint64_t ktr_compile = KTR_COMPILE;
   97 int     ktr_entries = KTR_BOOT_ENTRIES;
   98 int     ktr_version = KTR_VERSION;
   99 struct  ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
  100 struct  ktr_entry *ktr_buf = ktr_buf_init;
  101 cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
  102 
  103 static SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RD, 0, "KTR options");
  104 
  105 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD,
  106     &ktr_version, 0, "Version of the KTR interface");
  107 
  108 SYSCTL_UQUAD(_debug_ktr, OID_AUTO, compile, CTLFLAG_RD,
  109     &ktr_compile, 0, "Bitmask of KTR event classes compiled into the kernel");
  110 
  111 static int
  112 sysctl_debug_ktr_cpumask(SYSCTL_HANDLER_ARGS)
  113 {
  114         char lktr_cpumask_str[CPUSETBUFSIZ];
  115         cpuset_t imask;
  116         int error;
  117 
  118         cpusetobj_strprint(lktr_cpumask_str, &ktr_cpumask);
  119         error = sysctl_handle_string(oidp, lktr_cpumask_str,
  120             sizeof(lktr_cpumask_str), req);
  121         if (error != 0 || req->newptr == NULL)
  122                 return (error);
  123         if (cpusetobj_strscan(&imask, lktr_cpumask_str) == -1)
  124                 return (EINVAL);
  125         CPU_COPY(&imask, &ktr_cpumask);
  126 
  127         return (error);
  128 }
  129 SYSCTL_PROC(_debug_ktr, OID_AUTO, cpumask,
  130     CTLFLAG_RWTUN | CTLFLAG_MPSAFE | CTLTYPE_STRING, NULL, 0,
  131     sysctl_debug_ktr_cpumask, "S",
  132     "Bitmask of CPUs on which KTR logging is enabled");
  133 
  134 static int
  135 sysctl_debug_ktr_clear(SYSCTL_HANDLER_ARGS)
  136 {
  137         int clear, error;
  138 
  139         clear = 0;
  140         error = sysctl_handle_int(oidp, &clear, 0, req);
  141         if (error || !req->newptr)
  142                 return (error);
  143 
  144         if (clear) {
  145                 bzero(ktr_buf, sizeof(*ktr_buf) * ktr_entries);
  146                 ktr_idx = 0;
  147         }
  148 
  149         return (error);
  150 }
  151 SYSCTL_PROC(_debug_ktr, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
  152     sysctl_debug_ktr_clear, "I", "Clear KTR Buffer");
  153 
  154 /*
  155  * This is a sysctl proc so that it is serialized as !MPSAFE along with
  156  * the other ktr sysctl procs.
  157  */
  158 static int
  159 sysctl_debug_ktr_mask(SYSCTL_HANDLER_ARGS)
  160 {
  161         uint64_t mask;
  162         int error;
  163 
  164         mask = ktr_mask;
  165         error = sysctl_handle_64(oidp, &mask, 0, req);
  166         if (error || !req->newptr)
  167                 return (error);
  168         ktr_mask = mask;
  169         return (error);
  170 }
  171 
  172 SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_U64 | CTLFLAG_RWTUN, 0, 0,
  173     sysctl_debug_ktr_mask, "QU",
  174     "Bitmask of KTR event classes for which logging is enabled");
  175 
  176 #if KTR_ENTRIES > KTR_BOOT_ENTRIES
  177 /*
  178  * A simplified version of sysctl_debug_ktr_entries.
  179  * No need to care about SMP, scheduling, etc.
  180  */
  181 static void
  182 ktr_entries_initializer(void *dummy __unused)
  183 {
  184         uint64_t mask;
  185 
  186         /* Temporarily disable ktr in case malloc() is being traced. */
  187         mask = ktr_mask;
  188         ktr_mask = 0;
  189         ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
  190             M_WAITOK | M_ZERO);
  191         memcpy(ktr_buf, ktr_buf_init + ktr_idx,
  192             (KTR_BOOT_ENTRIES - ktr_idx) * sizeof(*ktr_buf));
  193         if (ktr_idx != 0) {
  194                 memcpy(ktr_buf + KTR_BOOT_ENTRIES - ktr_idx, ktr_buf_init,
  195                     ktr_idx * sizeof(*ktr_buf));
  196                 ktr_idx = KTR_BOOT_ENTRIES;
  197         }
  198         ktr_entries = KTR_ENTRIES;
  199         ktr_mask = mask;
  200 }
  201 SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
  202     ktr_entries_initializer, NULL);
  203 #endif
  204 
  205 static int
  206 sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
  207 {
  208         uint64_t mask;
  209         int entries, error;
  210         struct ktr_entry *buf, *oldbuf;
  211 
  212         entries = ktr_entries;
  213         error = sysctl_handle_int(oidp, &entries, 0, req);
  214         if (error || !req->newptr)
  215                 return (error);
  216         if (entries > KTR_ENTRIES_MAX)
  217                 return (ERANGE);
  218         /* Disable ktr temporarily. */
  219         mask = ktr_mask;
  220         ktr_mask = 0;
  221         /* Wait for threads to go idle. */
  222         if ((error = quiesce_all_cpus("ktrent", PCATCH)) != 0) {
  223                 ktr_mask = mask;
  224                 return (error);
  225         }
  226         if (ktr_buf != ktr_buf_init)
  227                 oldbuf = ktr_buf;
  228         else
  229                 oldbuf = NULL;
  230         /* Allocate a new buffer. */
  231         buf = malloc(sizeof(*buf) * entries, M_KTR, M_WAITOK | M_ZERO);
  232         /* Install the new buffer and restart ktr. */
  233         ktr_buf = buf;
  234         ktr_entries = entries;
  235         ktr_idx = 0;
  236         ktr_mask = mask;
  237         if (oldbuf != NULL)
  238                 free(oldbuf, M_KTR);
  239 
  240         return (error);
  241 }
  242 
  243 SYSCTL_PROC(_debug_ktr, OID_AUTO, entries, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
  244     sysctl_debug_ktr_entries, "I", "Number of entries in the KTR buffer");
  245 
  246 #ifdef KTR_VERBOSE
  247 int     ktr_verbose = KTR_VERBOSE;
  248 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
  249 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
  250 #endif
  251 
  252 #ifdef KTR_ALQ
  253 struct alq *ktr_alq;
  254 char    ktr_alq_file[MAXPATHLEN] = "/tmp/ktr.out";
  255 int     ktr_alq_cnt = 0;
  256 int     ktr_alq_depth = KTR_ENTRIES;
  257 int     ktr_alq_enabled = 0;
  258 int     ktr_alq_failed = 0;
  259 int     ktr_alq_max = 0;
  260 
  261 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_max, CTLFLAG_RW, &ktr_alq_max, 0,
  262     "Maximum number of entries to write");
  263 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_cnt, CTLFLAG_RD, &ktr_alq_cnt, 0,
  264     "Current number of written entries");
  265 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_failed, CTLFLAG_RD, &ktr_alq_failed, 0,
  266     "Number of times we overran the buffer");
  267 SYSCTL_INT(_debug_ktr, OID_AUTO, alq_depth, CTLFLAG_RW, &ktr_alq_depth, 0,
  268     "Number of items in the write buffer");
  269 SYSCTL_STRING(_debug_ktr, OID_AUTO, alq_file, CTLFLAG_RW, ktr_alq_file,
  270     sizeof(ktr_alq_file), "KTR logging file");
  271 
  272 static int
  273 sysctl_debug_ktr_alq_enable(SYSCTL_HANDLER_ARGS)
  274 {
  275         int error;
  276         int enable;
  277 
  278         enable = ktr_alq_enabled;
  279 
  280         error = sysctl_handle_int(oidp, &enable, 0, req);
  281         if (error || !req->newptr)
  282                 return (error);
  283 
  284         if (enable) {
  285                 if (ktr_alq_enabled)
  286                         return (0);
  287                 error = alq_open(&ktr_alq, (const char *)ktr_alq_file,
  288                     req->td->td_ucred, ALQ_DEFAULT_CMODE,
  289                     sizeof(struct ktr_entry), ktr_alq_depth);
  290                 if (error == 0) {
  291                         ktr_alq_cnt = 0;
  292                         ktr_alq_failed = 0;
  293                         ktr_alq_enabled = 1;
  294                 }
  295         } else {
  296                 if (ktr_alq_enabled == 0)
  297                         return (0);
  298                 ktr_alq_enabled = 0;
  299                 alq_close(ktr_alq);
  300                 ktr_alq = NULL;
  301         }
  302 
  303         return (error);
  304 }
  305 SYSCTL_PROC(_debug_ktr, OID_AUTO, alq_enable,
  306     CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_debug_ktr_alq_enable,
  307     "I", "Enable KTR logging");
  308 #endif
  309 
  310 void
  311 ktr_tracepoint(uint64_t mask, const char *file, int line, const char *format,
  312     u_long arg1, u_long arg2, u_long arg3, u_long arg4, u_long arg5,
  313     u_long arg6)
  314 {
  315         struct ktr_entry *entry;
  316 #ifdef KTR_ALQ
  317         struct ale *ale = NULL;
  318 #endif
  319         int newindex, saveindex;
  320 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  321         struct thread *td;
  322 #endif
  323         int cpu;
  324 
  325         if (panicstr || kdb_active)
  326                 return;
  327         if ((ktr_mask & mask) == 0 || ktr_buf == NULL)
  328                 return;
  329         cpu = KTR_CPU;
  330         if (!CPU_ISSET(cpu, &ktr_cpumask))
  331                 return;
  332 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  333         td = curthread;
  334         if (td->td_pflags & TDP_INKTR)
  335                 return;
  336         td->td_pflags |= TDP_INKTR;
  337 #endif
  338 #ifdef KTR_ALQ
  339         if (ktr_alq_enabled) {
  340                 if (td->td_critnest == 0 &&
  341                     (TD_IS_IDLETHREAD(td)) == 0 &&
  342                     td != ald_thread) {
  343                         if (ktr_alq_max && ktr_alq_cnt > ktr_alq_max)
  344                                 goto done;
  345                         if ((ale = alq_get(ktr_alq, ALQ_NOWAIT)) == NULL) {
  346                                 ktr_alq_failed++;
  347                                 goto done;
  348                         }
  349                         ktr_alq_cnt++;
  350                         entry = (struct ktr_entry *)ale->ae_data;
  351                 } else {
  352                         goto done;
  353                 }
  354         } else
  355 #endif
  356         {
  357                 do {
  358                         saveindex = ktr_idx;
  359                         newindex = (saveindex + 1) % ktr_entries;
  360                 } while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
  361                 entry = &ktr_buf[saveindex];
  362         }
  363         entry->ktr_timestamp = KTR_TIME;
  364         entry->ktr_cpu = cpu;
  365         entry->ktr_thread = curthread;
  366         if (file != NULL)
  367                 while (strncmp(file, "../", 3) == 0)
  368                         file += 3;
  369         entry->ktr_file = file;
  370         entry->ktr_line = line;
  371 #ifdef KTR_VERBOSE
  372         if (ktr_verbose) {
  373 #ifdef SMP
  374                 printf("cpu%d ", cpu);
  375 #endif
  376                 if (ktr_verbose > 1) {
  377                         printf("%s.%d\t", entry->ktr_file,
  378                             entry->ktr_line);
  379                 }
  380                 printf(format, arg1, arg2, arg3, arg4, arg5, arg6);
  381                 printf("\n");
  382         }
  383 #endif
  384         entry->ktr_desc = format;
  385         entry->ktr_parms[0] = arg1;
  386         entry->ktr_parms[1] = arg2;
  387         entry->ktr_parms[2] = arg3;
  388         entry->ktr_parms[3] = arg4;
  389         entry->ktr_parms[4] = arg5;
  390         entry->ktr_parms[5] = arg6;
  391 #ifdef KTR_ALQ
  392         if (ktr_alq_enabled && ale)
  393                 alq_post(ktr_alq, ale);
  394 done:
  395 #endif
  396 #if defined(KTR_VERBOSE) || defined(KTR_ALQ)
  397         td->td_pflags &= ~TDP_INKTR;
  398 #endif
  399 }
  400 
  401 #ifdef DDB
  402 
  403 struct tstate {
  404         int     cur;
  405         int     first;
  406 };
  407 static  struct tstate tstate;
  408 static  int db_ktr_verbose;
  409 static  int db_mach_vtrace(void);
  410 
  411 DB_SHOW_COMMAND(ktr, db_ktr_all)
  412 {
  413         
  414         tstate.cur = (ktr_idx - 1) % ktr_entries;
  415         tstate.first = -1;
  416         db_ktr_verbose = 0;
  417         db_ktr_verbose |= (strchr(modif, 'v') != NULL) ? 2 : 0;
  418         db_ktr_verbose |= (strchr(modif, 'V') != NULL) ? 1 : 0; /* just timestap please */
  419         if (strchr(modif, 'a') != NULL) {
  420                 db_disable_pager();
  421                 while (cncheckc() == -1)
  422                         if (db_mach_vtrace() == 0)
  423                                 break;
  424         } else {
  425                 while (!db_pager_quit)
  426                         if (db_mach_vtrace() == 0)
  427                                 break;
  428         }
  429 }
  430 
  431 static int
  432 db_mach_vtrace(void)
  433 {
  434         struct ktr_entry        *kp;
  435 
  436         if (tstate.cur == tstate.first || ktr_buf == NULL) {
  437                 db_printf("--- End of trace buffer ---\n");
  438                 return (0);
  439         }
  440         kp = &ktr_buf[tstate.cur];
  441 
  442         /* Skip over unused entries. */
  443         if (kp->ktr_desc == NULL) {
  444                 db_printf("--- End of trace buffer ---\n");
  445                 return (0);
  446         }
  447         db_printf("%d (%p", tstate.cur, kp->ktr_thread);
  448 #ifdef SMP
  449         db_printf(":cpu%d", kp->ktr_cpu);
  450 #endif
  451         db_printf(")");
  452         if (db_ktr_verbose >= 1) {
  453                 db_printf(" %10.10lld", (long long)kp->ktr_timestamp);
  454         }
  455         if (db_ktr_verbose >= 2) {
  456                 db_printf(" %s.%d", kp->ktr_file, kp->ktr_line);
  457         }
  458         db_printf(": ");
  459         db_printf(kp->ktr_desc, kp->ktr_parms[0], kp->ktr_parms[1],
  460             kp->ktr_parms[2], kp->ktr_parms[3], kp->ktr_parms[4],
  461             kp->ktr_parms[5]);
  462         db_printf("\n");
  463 
  464         if (tstate.first == -1)
  465                 tstate.first = tstate.cur;
  466 
  467         if (--tstate.cur < 0)
  468                 tstate.cur = ktr_entries - 1;
  469 
  470         return (1);
  471 }
  472 
  473 #endif  /* DDB */
Cache object: 7259a306de42ddde7154d0427730571c
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_ktr.c

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