bsd/dev/dtrace/sdt.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /* #pragma ident        "@(#)sdt.c      1.9     08/07/01 SMI" */
  27
  28 #ifdef KERNEL
  29 #ifndef _KERNEL
  30 #define _KERNEL /* Solaris vs. Darwin */
  31 #endif
  32 #endif
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/errno.h>
  37 #include <sys/stat.h>
  38 #include <sys/ioctl.h>
  39 #include <sys/conf.h>
  40 #include <sys/fcntl.h>
  41 #include <miscfs/devfs/devfs.h>
  42
  43 #if CONFIG_EMBEDDED
  44 #include <arm/caches_internal.h>
  45 #endif
  46
  47 #include <sys/dtrace.h>
  48 #include <sys/dtrace_impl.h>
  49
  50 #include <sys/dtrace_glue.h>
  51
  52 #include <sys/sdt_impl.h>
  53 extern int dtrace_kernel_symbol_mode;
  54
  55 /* #include <machine/trap.h */
  56 struct savearea_t; /* Used anonymously */
  57
  58 #if defined(__arm__)
  59 typedef kern_return_t (*perfCallback)(int, struct savearea_t *, __unused int, __unused int);
  60 extern perfCallback tempDTraceTrapHook;
  61 extern kern_return_t fbt_perfCallback(int, struct savearea_t *, __unused int, __unused int);
  62 #define SDT_PATCHVAL    0xdefc
  63 #define SDT_AFRAMES             7
  64 #elif defined(__arm64__)
  65 typedef kern_return_t (*perfCallback)(int, struct savearea_t *, __unused int, __unused int);
  66 extern perfCallback tempDTraceTrapHook;
  67 extern kern_return_t fbt_perfCallback(int, struct savearea_t *, __unused int, __unused int);
  68 #define SDT_PATCHVAL    0xe7eeee7e
  69 #define SDT_AFRAMES             7
  70 #elif defined(__x86_64__)
  71 typedef kern_return_t (*perfCallback)(int, struct savearea_t *, uintptr_t *, int);
  72 extern perfCallback tempDTraceTrapHook;
  73 extern kern_return_t fbt_perfCallback(int, struct savearea_t *, uintptr_t *, int);
  74 #define SDT_PATCHVAL    0xf0
  75 #define SDT_AFRAMES             6
  76 #else
  77 #error Unknown architecture
  78 #endif
  79
  80 #define SDT_PROBETAB_SIZE       0x1000          /* 4k entries -- 16K total */
  81
  82 #define DTRACE_PROBE_PREFIX "_dtrace_probe$"
  83
  84 static int                      sdt_verbose = 0;
  85 sdt_probe_t             **sdt_probetab;
  86 int                     sdt_probetab_size;
  87 int                     sdt_probetab_mask;
  88
  89 /*ARGSUSED*/
  90 static void
  91 __sdt_provide_module(void *arg, struct modctl *ctl)
  92 {
  93 #pragma unused(arg)
  94         struct module *mp = (struct module *)ctl->mod_address;
  95         char *modname = ctl->mod_modname;
  96         sdt_probedesc_t *sdpd;
  97         sdt_probe_t *sdp, *old;
  98         sdt_provider_t *prov;
  99         int len;
 100
 101         /*
 102          * One for all, and all for one:  if we haven't yet registered all of
 103          * our providers, we'll refuse to provide anything.
 104          */
 105         for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
 106                 if (prov->sdtp_id == DTRACE_PROVNONE) {
 107                         return;
 108                 }
 109         }
 110
 111         if (!mp || mp->sdt_nprobes != 0 || (sdpd = mp->sdt_probes) == NULL) {
 112                 return;
 113         }
 114
 115         for (sdpd = mp->sdt_probes; sdpd != NULL; sdpd = sdpd->sdpd_next) {
 116                 const char *name = sdpd->sdpd_name, *func;
 117                 char *nname;
 118                 int i, j;
 119                 dtrace_id_t id;
 120
 121                 for (prov = sdt_providers; prov->sdtp_prefix != NULL; prov++) {
 122                         const char *prefpart, *prefix = prov->sdtp_prefix;
 123
 124                         if ((prefpart = strstr(name, prefix))) {
 125                                 name = prefpart + strlen(prefix);
 126                                 break;
 127                         }
 128                 }
 129
 130                 nname = kmem_alloc(len = strlen(name) + 1, KM_SLEEP);
 131
 132                 for (i = 0, j = 0; name[j] != '\0'; i++) {
 133                         if (name[j] == '_' && name[j + 1] == '_') {
 134                                 nname[i] = '-';
 135                                 j += 2;
 136                         } else {
 137                                 nname[i] = name[j++];
 138                         }
 139                 }
 140
 141                 nname[i] = '\0';
 142
 143                 sdp = kmem_zalloc(sizeof(sdt_probe_t), KM_SLEEP);
 144                 sdp->sdp_loadcnt = ctl->mod_loadcnt;
 145                 sdp->sdp_ctl = ctl;
 146                 sdp->sdp_name = nname;
 147                 sdp->sdp_namelen = len;
 148                 sdp->sdp_provider = prov;
 149
 150                 func = sdpd->sdpd_func;
 151
 152                 if (func == NULL) {
 153                         func = "<unknown>";
 154                 }
 155
 156                 /*
 157                  * We have our provider.  Now create the probe.
 158                  */
 159                 if ((id = dtrace_probe_lookup(prov->sdtp_id, modname,
 160                     func, nname)) != DTRACE_IDNONE) {
 161                         old = dtrace_probe_arg(prov->sdtp_id, id);
 162                         ASSERT(old != NULL);
 163
 164                         sdp->sdp_next = old->sdp_next;
 165                         sdp->sdp_id = id;
 166                         old->sdp_next = sdp;
 167                 } else {
 168                         sdp->sdp_id = dtrace_probe_create(prov->sdtp_id,
 169                             modname, func, nname, SDT_AFRAMES, sdp);
 170
 171                         mp->sdt_nprobes++;
 172                 }
 173
 174 #if 0
 175                 printf("__sdt_provide_module:  sdpd=0x%p  sdp=0x%p  name=%s, id=%d\n", sdpd, sdp, nname, sdp->sdp_id);
 176 #endif
 177
 178                 sdp->sdp_hashnext =
 179                     sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)];
 180                 sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)] = sdp;
 181
 182                 sdp->sdp_patchval = SDT_PATCHVAL;
 183                 sdp->sdp_patchpoint = (sdt_instr_t *)sdpd->sdpd_offset;
 184                 sdp->sdp_savedval = *sdp->sdp_patchpoint;
 185         }
 186 }
 187
 188 /*ARGSUSED*/
 189 static void
 190 sdt_destroy(void *arg, dtrace_id_t id, void *parg)
 191 {
 192 #pragma unused(arg,id)
 193         sdt_probe_t *sdp = parg, *old, *last, *hash;
 194         int ndx;
 195
 196 #if !defined(__APPLE__)
 197         /*
 198          * APPLE NOTE:  sdt probes for kexts not yet implemented
 199          */
 200         struct modctl *ctl = sdp->sdp_ctl;
 201
 202         if (ctl != NULL && ctl->mod_loadcnt == sdp->sdp_loadcnt) {
 203                 if ((ctl->mod_loadcnt == sdp->sdp_loadcnt &&
 204                     ctl->mod_loaded)) {
 205                         ((struct module *)(ctl->mod_mp))->sdt_nprobes--;
 206                 }
 207         }
 208 #endif /* __APPLE__ */
 209
 210         while (sdp != NULL) {
 211                 old = sdp;
 212
 213                 /*
 214                  * Now we need to remove this probe from the sdt_probetab.
 215                  */
 216                 ndx = SDT_ADDR2NDX(sdp->sdp_patchpoint);
 217                 last = NULL;
 218                 hash = sdt_probetab[ndx];
 219
 220                 while (hash != sdp) {
 221                         ASSERT(hash != NULL);
 222                         last = hash;
 223                         hash = hash->sdp_hashnext;
 224                 }
 225
 226                 if (last != NULL) {
 227                         last->sdp_hashnext = sdp->sdp_hashnext;
 228                 } else {
 229                         sdt_probetab[ndx] = sdp->sdp_hashnext;
 230                 }
 231
 232                 kmem_free(sdp->sdp_name, sdp->sdp_namelen);
 233                 sdp = sdp->sdp_next;
 234                 kmem_free(old, sizeof(sdt_probe_t));
 235         }
 236 }
 237
 238 /*ARGSUSED*/
 239 static int
 240 sdt_enable(void *arg, dtrace_id_t id, void *parg)
 241 {
 242 #pragma unused(arg,id)
 243         sdt_probe_t *sdp = parg;
 244         struct modctl *ctl = sdp->sdp_ctl;
 245
 246         ctl->mod_nenabled++;
 247
 248         /*
 249          * If this module has disappeared since we discovered its probes,
 250          * refuse to enable it.
 251          */
 252         if (!ctl->mod_loaded) {
 253                 if (sdt_verbose) {
 254                         cmn_err(CE_NOTE, "sdt is failing for probe %s "
 255                             "(module %s unloaded)",
 256                             sdp->sdp_name, ctl->mod_modname);
 257                 }
 258                 goto err;
 259         }
 260
 261         /*
 262          * Now check that our modctl has the expected load count.  If it
 263          * doesn't, this module must have been unloaded and reloaded -- and
 264          * we're not going to touch it.
 265          */
 266         if (ctl->mod_loadcnt != sdp->sdp_loadcnt) {
 267                 if (sdt_verbose) {
 268                         cmn_err(CE_NOTE, "sdt is failing for probe %s "
 269                             "(module %s reloaded)",
 270                             sdp->sdp_name, ctl->mod_modname);
 271                 }
 272                 goto err;
 273         }
 274
 275         dtrace_casptr(&tempDTraceTrapHook, NULL, fbt_perfCallback);
 276         if (tempDTraceTrapHook != (perfCallback)fbt_perfCallback) {
 277                 if (sdt_verbose) {
 278                         cmn_err(CE_NOTE, "sdt_enable is failing for probe %s "
 279                             "in module %s: tempDTraceTrapHook already occupied.",
 280                             sdp->sdp_name, ctl->mod_modname);
 281                 }
 282                 return 0;
 283         }
 284
 285         while (sdp != NULL) {
 286                 (void)ml_nofault_copy((vm_offset_t)&sdp->sdp_patchval, (vm_offset_t)sdp->sdp_patchpoint,
 287                     (vm_size_t)sizeof(sdp->sdp_patchval));
 288
 289                 /*
 290                  * Make the patched instruction visible via a data + instruction
 291                  * cache fush on platforms that need it
 292                  */
 293                 flush_dcache((vm_offset_t)sdp->sdp_patchpoint, (vm_size_t)sizeof(sdp->sdp_patchval), 0);
 294                 invalidate_icache((vm_offset_t)sdp->sdp_patchpoint, (vm_size_t)sizeof(sdp->sdp_patchval), 0);
 295
 296                 sdp = sdp->sdp_next;
 297         }
 298
 299 err:
 300         return 0;
 301 }
 302
 303 /*ARGSUSED*/
 304 static void
 305 sdt_disable(void *arg, dtrace_id_t id, void *parg)
 306 {
 307 #pragma unused(arg,id)
 308         sdt_probe_t *sdp = parg;
 309         struct modctl *ctl = sdp->sdp_ctl;
 310
 311         ctl->mod_nenabled--;
 312
 313         if (!ctl->mod_loaded || ctl->mod_loadcnt != sdp->sdp_loadcnt) {
 314                 goto err;
 315         }
 316
 317         while (sdp != NULL) {
 318                 (void)ml_nofault_copy((vm_offset_t)&sdp->sdp_savedval, (vm_offset_t)sdp->sdp_patchpoint,
 319                     (vm_size_t)sizeof(sdp->sdp_savedval));
 320                 /*
 321                  * Make the patched instruction visible via a data + instruction
 322                  * cache flush on platforms that need it
 323                  */
 324                 flush_dcache((vm_offset_t)sdp->sdp_patchpoint, (vm_size_t)sizeof(sdp->sdp_savedval), 0);
 325                 invalidate_icache((vm_offset_t)sdp->sdp_patchpoint, (vm_size_t)sizeof(sdp->sdp_savedval), 0);
 326                 sdp = sdp->sdp_next;
 327         }
 328
 329 err:
 330         ;
 331 }
 332
 333 static dtrace_pops_t sdt_pops = {
 334         .dtps_provide =         NULL,
 335         .dtps_provide_module =  sdt_provide_module,
 336         .dtps_enable =          sdt_enable,
 337         .dtps_disable =         sdt_disable,
 338         .dtps_suspend =         NULL,
 339         .dtps_resume =          NULL,
 340         .dtps_getargdesc =      sdt_getargdesc,
 341         .dtps_getargval =       sdt_getarg,
 342         .dtps_usermode =        NULL,
 343         .dtps_destroy =         sdt_destroy,
 344 };
 345
 346 /*ARGSUSED*/
 347 static int
 348 sdt_attach(dev_info_t *devi)
 349 {
 350         sdt_provider_t *prov;
 351
 352         if (ddi_create_minor_node(devi, "sdt", S_IFCHR,
 353             0, DDI_PSEUDO, 0) == DDI_FAILURE) {
 354                 cmn_err(CE_NOTE, "/dev/sdt couldn't create minor node");
 355                 ddi_remove_minor_node(devi, NULL);
 356                 return DDI_FAILURE;
 357         }
 358
 359         if (sdt_probetab_size == 0) {
 360                 sdt_probetab_size = SDT_PROBETAB_SIZE;
 361         }
 362
 363         sdt_probetab_mask = sdt_probetab_size - 1;
 364         sdt_probetab =
 365             kmem_zalloc(sdt_probetab_size * sizeof(sdt_probe_t *), KM_SLEEP);
 366         dtrace_invop_add(sdt_invop);
 367
 368         for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
 369                 if (dtrace_register(prov->sdtp_name, prov->sdtp_attr,
 370                     DTRACE_PRIV_KERNEL, NULL,
 371                     &sdt_pops, prov, &prov->sdtp_id) != 0) {
 372                         cmn_err(CE_WARN, "failed to register sdt provider %s",
 373                             prov->sdtp_name);
 374                 }
 375         }
 376
 377         return DDI_SUCCESS;
 378 }
 379
 380 /*
 381  * APPLE NOTE:  sdt_detach not implemented
 382  */
 383 #if !defined(__APPLE__)
 384 /*ARGSUSED*/
 385 static int
 386 sdt_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
 387 {
 388         sdt_provider_t *prov;
 389
 390         switch (cmd) {
 391         case DDI_DETACH:
 392                 break;
 393
 394         case DDI_SUSPEND:
 395                 return DDI_SUCCESS;
 396
 397         default:
 398                 return DDI_FAILURE;
 399         }
 400
 401         for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
 402                 if (prov->sdtp_id != DTRACE_PROVNONE) {
 403                         if (dtrace_unregister(prov->sdtp_id) != 0) {
 404                                 return DDI_FAILURE;
 405                         }
 406
 407                         prov->sdtp_id = DTRACE_PROVNONE;
 408                 }
 409         }
 410
 411         dtrace_invop_remove(sdt_invop);
 412         kmem_free(sdt_probetab, sdt_probetab_size * sizeof(sdt_probe_t *));
 413
 414         return DDI_SUCCESS;
 415 }
 416 #endif /* __APPLE__ */
 417
 418 d_open_t _sdt_open;
 419
 420 int
 421 _sdt_open(dev_t dev, int flags, int devtype, struct proc *p)
 422 {
 423 #pragma unused(dev,flags,devtype,p)
 424         return 0;
 425 }
 426
 427 #define SDT_MAJOR  -24 /* let the kernel pick the device number */
 428
 429 /*
 430  * A struct describing which functions will get invoked for certain
 431  * actions.
 432  */
 433 static struct cdevsw sdt_cdevsw =
 434 {
 435         _sdt_open,              /* open */
 436         eno_opcl,                       /* close */
 437         eno_rdwrt,                      /* read */
 438         eno_rdwrt,                      /* write */
 439         eno_ioctl,                      /* ioctl */
 440         (stop_fcn_t *)nulldev, /* stop */
 441         (reset_fcn_t *)nulldev, /* reset */
 442         NULL,                           /* tty's */
 443         eno_select,                     /* select */
 444         eno_mmap,                       /* mmap */
 445         eno_strat,                      /* strategy */
 446         eno_getc,                       /* getc */
 447         eno_putc,                       /* putc */
 448         0                                       /* type */
 449 };
 450
 451 static struct modctl g_sdt_kernctl;
 452 static struct module g_sdt_mach_module;
 453
 454 #include <mach-o/nlist.h>
 455 #include <libkern/kernel_mach_header.h>
 456
 457 void
 458 sdt_early_init( void )
 459 {
 460         if (dtrace_sdt_probes_restricted()) {
 461                 return;
 462         }
 463         if (MH_MAGIC_KERNEL != _mh_execute_header.magic) {
 464                 g_sdt_kernctl.mod_address = (vm_address_t)NULL;
 465                 g_sdt_kernctl.mod_size = 0;
 466         } else {
 467                 kernel_mach_header_t        *mh;
 468                 struct load_command         *cmd;
 469                 kernel_segment_command_t    *orig_ts = NULL, *orig_le = NULL;
 470                 struct symtab_command       *orig_st = NULL;
 471                 kernel_nlist_t              *sym = NULL;
 472                 char                        *strings;
 473                 unsigned int                i;
 474
 475                 g_sdt_mach_module.sdt_nprobes = 0;
 476                 g_sdt_mach_module.sdt_probes = NULL;
 477
 478                 g_sdt_kernctl.mod_address = (vm_address_t)&g_sdt_mach_module;
 479                 g_sdt_kernctl.mod_size = 0;
 480                 strncpy((char *)&(g_sdt_kernctl.mod_modname), "mach_kernel", KMOD_MAX_NAME);
 481
 482                 g_sdt_kernctl.mod_next = NULL;
 483                 g_sdt_kernctl.mod_stale = NULL;
 484                 g_sdt_kernctl.mod_id = 0;
 485                 g_sdt_kernctl.mod_loadcnt = 1;
 486                 g_sdt_kernctl.mod_loaded = 1;
 487                 g_sdt_kernctl.mod_flags = 0;
 488                 g_sdt_kernctl.mod_nenabled = 0;
 489
 490                 mh = &_mh_execute_header;
 491                 cmd = (struct load_command*) &mh[1];
 492                 for (i = 0; i < mh->ncmds; i++) {
 493                         if (cmd->cmd == LC_SEGMENT_KERNEL) {
 494                                 kernel_segment_command_t *orig_sg = (kernel_segment_command_t *) cmd;
 495
 496                                 if (LIT_STRNEQL(orig_sg->segname, SEG_TEXT)) {
 497                                         orig_ts = orig_sg;
 498                                 } else if (LIT_STRNEQL(orig_sg->segname, SEG_LINKEDIT)) {
 499                                         orig_le = orig_sg;
 500                                 } else if (LIT_STRNEQL(orig_sg->segname, "")) {
 501                                         orig_ts = orig_sg; /* kexts have a single unnamed segment */
 502                                 }
 503                         } else if (cmd->cmd == LC_SYMTAB) {
 504                                 orig_st = (struct symtab_command *) cmd;
 505                         }
 506
 507                         cmd = (struct load_command *) ((uintptr_t) cmd + cmd->cmdsize);
 508                 }
 509
 510                 if ((orig_ts == NULL) || (orig_st == NULL) || (orig_le == NULL)) {
 511                         return;
 512                 }
 513
 514                 sym = (kernel_nlist_t *)(orig_le->vmaddr + orig_st->symoff - orig_le->fileoff);
 515                 strings = (char *)(orig_le->vmaddr + orig_st->stroff - orig_le->fileoff);
 516
 517                 for (i = 0; i < orig_st->nsyms; i++) {
 518                         uint8_t n_type = sym[i].n_type & (N_TYPE | N_EXT);
 519                         char *name = strings + sym[i].n_un.n_strx;
 520                         const char *prev_name;
 521                         unsigned long best;
 522                         unsigned int j;
 523
 524                         /* Check that the symbol is a global and that it has a name. */
 525                         if (((N_SECT | N_EXT) != n_type && (N_ABS | N_EXT) != n_type)) {
 526                                 continue;
 527                         }
 528
 529                         if (0 == sym[i].n_un.n_strx) { /* iff a null, "", name. */
 530                                 continue;
 531                         }
 532
 533                         /* Lop off omnipresent leading underscore. */
 534                         if (*name == '_') {
 535                                 name += 1;
 536                         }
 537
 538                         if (strncmp(name, DTRACE_PROBE_PREFIX, sizeof(DTRACE_PROBE_PREFIX) - 1) == 0) {
 539                                 sdt_probedesc_t *sdpd = kmem_alloc(sizeof(sdt_probedesc_t), KM_SLEEP);
 540                                 int len = strlen(name) + 1;
 541
 542                                 sdpd->sdpd_name = kmem_alloc(len, KM_SLEEP);
 543                                 strncpy(sdpd->sdpd_name, name, len); /* NUL termination is ensured. */
 544
 545                                 prev_name = "<unknown>";
 546                                 best = 0;
 547
 548                                 /*
 549                                  * Find the symbol immediately preceding the sdt probe site just discovered,
 550                                  * that symbol names the function containing the sdt probe.
 551                                  */
 552                                 for (j = 0; j < orig_st->nsyms; j++) {
 553                                         uint8_t jn_type = sym[j].n_type & N_TYPE;
 554                                         char *jname = strings + sym[j].n_un.n_strx;
 555
 556                                         if ((N_SECT != jn_type && N_ABS != jn_type)) {
 557                                                 continue;
 558                                         }
 559
 560                                         if (0 == sym[j].n_un.n_strx) { /* iff a null, "", name. */
 561                                                 continue;
 562                                         }
 563
 564                                         if (*jname == '_') {
 565                                                 jname += 1;
 566                                         }
 567
 568                                         if (*(unsigned long *)sym[i].n_value <= (unsigned long)sym[j].n_value) {
 569                                                 continue;
 570                                         }
 571
 572                                         if ((unsigned long)sym[j].n_value > best) {
 573                                                 best = (unsigned long)sym[j].n_value;
 574                                                 prev_name = jname;
 575                                         }
 576                                 }
 577
 578                                 sdpd->sdpd_func = kmem_alloc((len = strlen(prev_name) + 1), KM_SLEEP);
 579                                 strncpy(sdpd->sdpd_func, prev_name, len); /* NUL termination is ensured. */
 580
 581                                 sdpd->sdpd_offset = *(unsigned long *)sym[i].n_value;
 582 #if defined(__arm__)
 583                                 /* PR8353094 - mask off thumb-bit */
 584                                 sdpd->sdpd_offset &= ~0x1U;
 585 #elif defined(__arm64__)
 586                                 sdpd->sdpd_offset &= ~0x1LU;
 587 #endif  /* __arm__ */
 588
 589 #if 0
 590                                 printf("sdt_init: sdpd_offset=0x%lx, n_value=0x%lx, name=%s\n",
 591                                     sdpd->sdpd_offset, *(unsigned long *)sym[i].n_value, name);
 592 #endif
 593
 594                                 sdpd->sdpd_next = g_sdt_mach_module.sdt_probes;
 595                                 g_sdt_mach_module.sdt_probes = sdpd;
 596                         } else {
 597                                 prev_name = name;
 598                         }
 599                 }
 600         }
 601 }
 602
 603 void
 604 sdt_init( void )
 605 {
 606         int majdevno = cdevsw_add(SDT_MAJOR, &sdt_cdevsw);
 607
 608         if (majdevno < 0) {
 609                 printf("sdt_init: failed to allocate a major number!\n");
 610                 return;
 611         }
 612
 613         if (dtrace_sdt_probes_restricted()) {
 614                 return;
 615         }
 616
 617         sdt_attach((dev_info_t*)(uintptr_t)majdevno);
 618 }
 619
 620 #undef SDT_MAJOR
 621
 622 /*ARGSUSED*/
 623 void
 624 sdt_provide_module(void *arg, struct modctl *ctl)
 625 {
 626 #pragma unused(arg)
 627         ASSERT(ctl != NULL);
 628         ASSERT(dtrace_kernel_symbol_mode != DTRACE_KERNEL_SYMBOLS_NEVER);
 629         LCK_MTX_ASSERT(&mod_lock, LCK_MTX_ASSERT_OWNED);
 630
 631         if (MOD_SDT_DONE(ctl)) {
 632                 return;
 633         }
 634
 635         if (MOD_IS_MACH_KERNEL(ctl)) {
 636                 __sdt_provide_module(arg, &g_sdt_kernctl);
 637
 638                 sdt_probedesc_t *sdpd = g_sdt_mach_module.sdt_probes;
 639                 while (sdpd) {
 640                         sdt_probedesc_t *this_sdpd = sdpd;
 641                         kmem_free((void *)sdpd->sdpd_name, strlen(sdpd->sdpd_name) + 1);
 642                         kmem_free((void *)sdpd->sdpd_func, strlen(sdpd->sdpd_func) + 1);
 643                         sdpd = sdpd->sdpd_next;
 644                         kmem_free((void *)this_sdpd, sizeof(sdt_probedesc_t));
 645                 }
 646                 g_sdt_mach_module.sdt_probes = NULL;
 647         } else {
 648                 /*
 649                  * APPLE NOTE:  sdt probes for kexts not yet implemented
 650                  */
 651         }
 652
 653         /* Need to mark this module as completed */
 654         ctl->mod_flags |= MODCTL_SDT_PROBES_PROVIDED;
 655 }