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#include <sys/dtrace.h> 44#include <sys/dtrace_impl.h> 45 46#include <sys/dtrace_glue.h> 47 48#include <sys/sdt_impl.h> 49extern int dtrace_kernel_symbol_mode; 50 51struct savearea_t; /* Used anonymously */ 52typedef kern_return_t (*perfCallback)(int, struct savearea_t *, uintptr_t *, int); 53 54#if defined(__i386__) || defined(__x86_64__) 55extern perfCallback tempDTraceTrapHook; 56extern kern_return_t fbt_perfCallback(int, struct savearea_t *, int, int); 57 58#define SDT_PATCHVAL 0xf0 59#define SDT_AFRAMES 6 60#else 61#error Unknown architecture 62#endif 63 64#define SDT_PROBETAB_SIZE 0x1000 /* 4k entries -- 16K total */ 65 66#define DTRACE_PROBE_PREFIX "_dtrace_probe$" 67 68static dev_info_t *sdt_devi; 69static int sdt_verbose = 0; 70sdt_probe_t **sdt_probetab; 71int sdt_probetab_size; 72int sdt_probetab_mask; 73 74/*ARGSUSED*/ 75static void 76__sdt_provide_module(void *arg, struct modctl *ctl) 77{ 78#pragma unused(arg) 79 struct module *mp = (struct module *)ctl->mod_address; 80 char *modname = ctl->mod_modname; 81 sdt_probedesc_t *sdpd; 82 sdt_probe_t *sdp, *old; 83 sdt_provider_t *prov; 84 int len; 85 86 /* 87 * One for all, and all for one: if we haven't yet registered all of 88 * our providers, we'll refuse to provide anything. 89 */ 90 for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) { 91 if (prov->sdtp_id == DTRACE_PROVNONE) 92 return; 93 } 94 95 if (!mp || mp->sdt_nprobes != 0 || (sdpd = mp->sdt_probes) == NULL) 96 return; 97 98 for (sdpd = mp->sdt_probes; sdpd != NULL; sdpd = sdpd->sdpd_next) { 99 const char *name = sdpd->sdpd_name, *func; 100 char *nname; 101 int i, j; 102 dtrace_id_t id; 103 104 for (prov = sdt_providers; prov->sdtp_prefix != NULL; prov++) { 105 const char *prefpart, *prefix = prov->sdtp_prefix; 106 107 if ((prefpart = strstr(name, prefix))) { 108 name = prefpart + strlen(prefix); 109 break; 110 } 111 } 112 113 nname = kmem_alloc(len = strlen(name) + 1, KM_SLEEP); 114 115 for (i = 0, j = 0; name[j] != '\0'; i++) { 116 if (name[j] == '_' && name[j + 1] == '_') { 117 nname[i] = '-'; 118 j += 2; 119 } else { 120 nname[i] = name[j++]; 121 } 122 } 123 124 nname[i] = '\0'; 125 126 sdp = kmem_zalloc(sizeof (sdt_probe_t), KM_SLEEP); 127 sdp->sdp_loadcnt = ctl->mod_loadcnt; 128 sdp->sdp_ctl = ctl; 129 sdp->sdp_name = nname; 130 sdp->sdp_namelen = len; 131 sdp->sdp_provider = prov; 132 133 func = sdpd->sdpd_func; 134 135 if (func == NULL) 136 func = "<unknown>"; 137 138 /* 139 * We have our provider. Now create the probe. 140 */ 141 if ((id = dtrace_probe_lookup(prov->sdtp_id, modname, 142 func, nname)) != DTRACE_IDNONE) { 143 old = dtrace_probe_arg(prov->sdtp_id, id); 144 ASSERT(old != NULL); 145 146 sdp->sdp_next = old->sdp_next; 147 sdp->sdp_id = id; 148 old->sdp_next = sdp; 149 } else { 150 sdp->sdp_id = dtrace_probe_create(prov->sdtp_id, 151 modname, func, nname, SDT_AFRAMES, sdp); 152 153 mp->sdt_nprobes++; 154 } 155 156 sdp->sdp_hashnext = 157 sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)]; 158 sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)] = sdp; 159 160 sdp->sdp_patchval = SDT_PATCHVAL; 161 sdp->sdp_patchpoint = (sdt_instr_t *)sdpd->sdpd_offset; 162 sdp->sdp_savedval = *sdp->sdp_patchpoint; 163 } 164} 165 166/*ARGSUSED*/ 167static void 168sdt_destroy(void *arg, dtrace_id_t id, void *parg) 169{ 170#pragma unused(arg,id) 171 sdt_probe_t *sdp = parg, *old, *last, *hash; 172 int ndx; 173#if !defined(__APPLE__) 174 struct modctl *ctl = sdp->sdp_ctl; 175 176 if (ctl != NULL && ctl->mod_loadcnt == sdp->sdp_loadcnt) { 177 if ((ctl->mod_loadcnt == sdp->sdp_loadcnt && 178 ctl->mod_loaded)) { 179 ((struct module *)(ctl->mod_mp))->sdt_nprobes--; 180 } 181 } 182#endif /* __APPLE__ */ 183 184 while (sdp != NULL) { 185 old = sdp; 186 187 /* 188 * Now we need to remove this probe from the sdt_probetab. 189 */ 190 ndx = SDT_ADDR2NDX(sdp->sdp_patchpoint); 191 last = NULL; 192 hash = sdt_probetab[ndx]; 193 194 while (hash != sdp) { 195 ASSERT(hash != NULL); 196 last = hash; 197 hash = hash->sdp_hashnext; 198 } 199 200 if (last != NULL) { 201 last->sdp_hashnext = sdp->sdp_hashnext; 202 } else { 203 sdt_probetab[ndx] = sdp->sdp_hashnext; 204 } 205 206 kmem_free(sdp->sdp_name, sdp->sdp_namelen); 207 sdp = sdp->sdp_next; 208 kmem_free(old, sizeof (sdt_probe_t)); 209 } 210} 211 212/*ARGSUSED*/ 213static int 214sdt_enable(void *arg, dtrace_id_t id, void *parg) 215{ 216#pragma unused(arg,id) 217 sdt_probe_t *sdp = parg; 218 struct modctl *ctl = sdp->sdp_ctl; 219 220 ctl->mod_nenabled++; 221 222 /* 223 * If this module has disappeared since we discovered its probes, 224 * refuse to enable it. 225 */ 226 if (!ctl->mod_loaded) { 227 if (sdt_verbose) { 228 cmn_err(CE_NOTE, "sdt is failing for probe %s " 229 "(module %s unloaded)", 230 sdp->sdp_name, ctl->mod_modname); 231 } 232 goto err; 233 } 234 235 /* 236 * Now check that our modctl has the expected load count. If it 237 * doesn't, this module must have been unloaded and reloaded -- and 238 * we're not going to touch it. 239 */ 240 if (ctl->mod_loadcnt != sdp->sdp_loadcnt) { 241 if (sdt_verbose) { 242 cmn_err(CE_NOTE, "sdt is failing for probe %s " 243 "(module %s reloaded)", 244 sdp->sdp_name, ctl->mod_modname); 245 } 246 goto err; 247 } 248 249 dtrace_casptr(&tempDTraceTrapHook, NULL, fbt_perfCallback); 250 if (tempDTraceTrapHook != (perfCallback)fbt_perfCallback) { 251 if (sdt_verbose) { 252 cmn_err(CE_NOTE, "sdt_enable is failing for probe %s " 253 "in module %s: tempDTraceTrapHook already occupied.", 254 sdp->sdp_name, ctl->mod_modname); 255 } 256 return (0); 257 } 258 259 while (sdp != NULL) { 260 (void)ml_nofault_copy( (vm_offset_t)&sdp->sdp_patchval, (vm_offset_t)sdp->sdp_patchpoint, 261 (vm_size_t)sizeof(sdp->sdp_patchval)); 262 sdp = sdp->sdp_next; 263 } 264 265err: 266 return (0); 267} 268 269/*ARGSUSED*/ 270static void 271sdt_disable(void *arg, dtrace_id_t id, void *parg) 272{ 273#pragma unused(arg,id) 274 sdt_probe_t *sdp = parg; 275 struct modctl *ctl = sdp->sdp_ctl; 276 277 ctl->mod_nenabled--; 278 279 if (!ctl->mod_loaded || ctl->mod_loadcnt != sdp->sdp_loadcnt) 280 goto err; 281 282 while (sdp != NULL) { 283 (void)ml_nofault_copy( (vm_offset_t)&sdp->sdp_savedval, (vm_offset_t)sdp->sdp_patchpoint, 284 (vm_size_t)sizeof(sdp->sdp_savedval)); 285 sdp = sdp->sdp_next; 286 } 287 288err: 289 ; 290} 291 292static dtrace_pops_t sdt_pops = { 293 NULL, 294 sdt_provide_module, 295 sdt_enable, 296 sdt_disable, 297 NULL, 298 NULL, 299 sdt_getargdesc, 300 sdt_getarg, 301 NULL, 302 sdt_destroy 303}; 304 305/*ARGSUSED*/ 306static int 307sdt_attach(dev_info_t *devi, ddi_attach_cmd_t cmd) 308{ 309#pragma unused(cmd) 310 sdt_provider_t *prov; 311 312 if (ddi_create_minor_node(devi, "sdt", S_IFCHR, 313 0, DDI_PSEUDO, 0) == DDI_FAILURE) { 314 cmn_err(CE_NOTE, "/dev/sdt couldn't create minor node"); 315 ddi_remove_minor_node(devi, NULL); 316 return (DDI_FAILURE); 317 } 318 319 ddi_report_dev(devi); 320 sdt_devi = devi; 321 322 if (sdt_probetab_size == 0) 323 sdt_probetab_size = SDT_PROBETAB_SIZE; 324 325 sdt_probetab_mask = sdt_probetab_size - 1; 326 sdt_probetab = 327 kmem_zalloc(sdt_probetab_size * sizeof (sdt_probe_t *), KM_SLEEP); 328 dtrace_invop_add(sdt_invop); 329 330 for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) { 331 if (dtrace_register(prov->sdtp_name, prov->sdtp_attr, 332 DTRACE_PRIV_KERNEL, NULL, 333 &sdt_pops, prov, &prov->sdtp_id) != 0) { 334 cmn_err(CE_WARN, "failed to register sdt provider %s", 335 prov->sdtp_name); 336 } 337 } 338 339 return (DDI_SUCCESS); 340} 341 342#if !defined(__APPLE__) 343/*ARGSUSED*/ 344static int 345sdt_detach(dev_info_t *dip, ddi_detach_cmd_t cmd) 346{ 347 sdt_provider_t *prov; 348 349 switch (cmd) { 350 case DDI_DETACH: 351 break; 352 353 case DDI_SUSPEND: 354 return (DDI_SUCCESS); 355 356 default: 357 return (DDI_FAILURE); 358 } 359 360 for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) { 361 if (prov->sdtp_id != DTRACE_PROVNONE) { 362 if (dtrace_unregister(prov->sdtp_id) != 0) 363 return (DDI_FAILURE); 364 365 prov->sdtp_id = DTRACE_PROVNONE; 366 } 367 } 368 369 dtrace_invop_remove(sdt_invop); 370 kmem_free(sdt_probetab, sdt_probetab_size * sizeof (sdt_probe_t *)); 371 372 return (DDI_SUCCESS); 373} 374 375/*ARGSUSED*/ 376static int 377sdt_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) 378{ 379 int error; 380 381 switch (infocmd) { 382 case DDI_INFO_DEVT2DEVINFO: 383 *result = (void *)sdt_devi; 384 error = DDI_SUCCESS; 385 break; 386 case DDI_INFO_DEVT2INSTANCE: 387 *result = (void *)0; 388 error = DDI_SUCCESS; 389 break; 390 default: 391 error = DDI_FAILURE; 392 } 393 return (error); 394} 395 396/*ARGSUSED*/ 397static int 398sdt_open(dev_t *devp, int flag, int otyp, cred_t *cred_p) 399{ 400 return (0); 401} 402 403static struct cb_ops sdt_cb_ops = { 404 sdt_open, /* open */ 405 nodev, /* close */ 406 nulldev, /* strategy */ 407 nulldev, /* print */ 408 nodev, /* dump */ 409 nodev, /* read */ 410 nodev, /* write */ 411 nodev, /* ioctl */ 412 nodev, /* devmap */ 413 nodev, /* mmap */ 414 nodev, /* segmap */ 415 nochpoll, /* poll */ 416 ddi_prop_op, /* cb_prop_op */ 417 0, /* streamtab */ 418 D_NEW | D_MP /* Driver compatibility flag */ 419}; 420 421static struct dev_ops sdt_ops = { 422 DEVO_REV, /* devo_rev, */ 423 0, /* refcnt */ 424 sdt_info, /* get_dev_info */ 425 nulldev, /* identify */ 426 nulldev, /* probe */ 427 sdt_attach, /* attach */ 428 sdt_detach, /* detach */ 429 nodev, /* reset */ 430 &sdt_cb_ops, /* driver operations */ 431 NULL, /* bus operations */ 432 nodev /* dev power */ 433}; 434 435/* 436 * Module linkage information for the kernel. 437 */ 438static struct modldrv modldrv = { 439 &mod_driverops, /* module type (this is a pseudo driver) */ 440 "Statically Defined Tracing", /* name of module */ 441 &sdt_ops, /* driver ops */ 442}; 443 444static struct modlinkage modlinkage = { 445 MODREV_1, 446 (void *)&modldrv, 447 NULL 448}; 449 450int 451_init(void) 452{ 453 return (mod_install(&modlinkage)); 454} 455 456int 457_info(struct modinfo *modinfop) 458{ 459 return (mod_info(&modlinkage, modinfop)); 460} 461 462int 463_fini(void) 464{ 465 return (mod_remove(&modlinkage)); 466} 467#else 468d_open_t _sdt_open; 469 470int _sdt_open(dev_t dev, int flags, int devtype, struct proc *p) 471{ 472#pragma unused(dev,flags,devtype,p) 473 return 0; 474} 475 476#define SDT_MAJOR -24 /* let the kernel pick the device number */ 477 478/* 479 * A struct describing which functions will get invoked for certain 480 * actions. 481 */ 482static struct cdevsw sdt_cdevsw = 483{ 484 _sdt_open, /* open */ 485 eno_opcl, /* close */ 486 eno_rdwrt, /* read */ 487 eno_rdwrt, /* write */ 488 eno_ioctl, /* ioctl */ 489 (stop_fcn_t *)nulldev, /* stop */ 490 (reset_fcn_t *)nulldev, /* reset */ 491 NULL, /* tty's */ 492 eno_select, /* select */ 493 eno_mmap, /* mmap */ 494 eno_strat, /* strategy */ 495 eno_getc, /* getc */ 496 eno_putc, /* putc */ 497 0 /* type */ 498}; 499 500static int gSDTInited = 0; 501static struct modctl g_sdt_kernctl; 502static struct module g_sdt_mach_module; 503 504#include <mach-o/nlist.h> 505#include <libkern/kernel_mach_header.h> 506 507void sdt_init( void ) 508{ 509 if (0 == gSDTInited) 510 { 511 int majdevno = cdevsw_add(SDT_MAJOR, &sdt_cdevsw); 512 513 if (majdevno < 0) { 514 printf("sdt_init: failed to allocate a major number!\n"); 515 gSDTInited = 0; 516 return; 517 } 518 519 if (MH_MAGIC_KERNEL != _mh_execute_header.magic) { 520 g_sdt_kernctl.mod_address = (vm_address_t)NULL; 521 g_sdt_kernctl.mod_size = 0; 522 } else { 523 kernel_mach_header_t *mh; 524 struct load_command *cmd; 525 kernel_segment_command_t *orig_ts = NULL, *orig_le = NULL; 526 struct symtab_command *orig_st = NULL; 527 kernel_nlist_t *sym = NULL; 528 char *strings; 529 unsigned int i; 530 531 g_sdt_mach_module.sdt_nprobes = 0; 532 g_sdt_mach_module.sdt_probes = NULL; 533 534 g_sdt_kernctl.mod_address = (vm_address_t)&g_sdt_mach_module; 535 g_sdt_kernctl.mod_size = 0; 536 strncpy((char *)&(g_sdt_kernctl.mod_modname), "mach_kernel", KMOD_MAX_NAME); 537 538 g_sdt_kernctl.mod_next = NULL; 539 g_sdt_kernctl.mod_stale = NULL; 540 g_sdt_kernctl.mod_id = 0; 541 g_sdt_kernctl.mod_loadcnt = 1; 542 g_sdt_kernctl.mod_loaded = 1; 543 g_sdt_kernctl.mod_flags = 0; 544 g_sdt_kernctl.mod_nenabled = 0; 545 546 mh = &_mh_execute_header; 547 cmd = (struct load_command*) &mh[1]; 548 for (i = 0; i < mh->ncmds; i++) { 549 if (cmd->cmd == LC_SEGMENT_KERNEL) { 550 kernel_segment_command_t *orig_sg = (kernel_segment_command_t *) cmd; 551 552 if (LIT_STRNEQL(orig_sg->segname, SEG_TEXT)) 553 orig_ts = orig_sg; 554 else if (LIT_STRNEQL(orig_sg->segname, SEG_LINKEDIT)) 555 orig_le = orig_sg; 556 else if (LIT_STRNEQL(orig_sg->segname, "")) 557 orig_ts = orig_sg; /* kexts have a single unnamed segment */ 558 } 559 else if (cmd->cmd == LC_SYMTAB) 560 orig_st = (struct symtab_command *) cmd; 561 562 cmd = (struct load_command *) ((uintptr_t) cmd + cmd->cmdsize); 563 } 564 565 if ((orig_ts == NULL) || (orig_st == NULL) || (orig_le == NULL)) 566 return; 567 568 sym = (kernel_nlist_t *)(orig_le->vmaddr + orig_st->symoff - orig_le->fileoff); 569 strings = (char *)(orig_le->vmaddr + orig_st->stroff - orig_le->fileoff); 570 571 for (i = 0; i < orig_st->nsyms; i++) { 572 uint8_t n_type = sym[i].n_type & (N_TYPE | N_EXT); 573 char *name = strings + sym[i].n_un.n_strx; 574 const char *prev_name; 575 unsigned long best; 576 unsigned int j; 577 578 /* Check that the symbol is a global and that it has a name. */ 579 if (((N_SECT | N_EXT) != n_type && (N_ABS | N_EXT) != n_type)) 580 continue; 581 582 if (0 == sym[i].n_un.n_strx) /* iff a null, "", name. */ 583 continue; 584 585 /* Lop off omnipresent leading underscore. */ 586 if (*name == '_') 587 name += 1; 588 589 if (strncmp(name, DTRACE_PROBE_PREFIX, sizeof(DTRACE_PROBE_PREFIX) - 1) == 0) { 590 sdt_probedesc_t *sdpd = kmem_alloc(sizeof(sdt_probedesc_t), KM_SLEEP); 591 int len = strlen(name) + 1; 592 593 sdpd->sdpd_name = kmem_alloc(len, KM_SLEEP); 594 strncpy(sdpd->sdpd_name, name, len); /* NUL termination is ensured. */ 595 596 prev_name = "<unknown>"; 597 best = 0; 598 599 /* 600 * Find the symbol immediately preceding the sdt probe site just discovered, 601 * that symbol names the function containing the sdt probe. 602 */ 603 for (j = 0; j < orig_st->nsyms; j++) { 604 uint8_t jn_type = sym[j].n_type & (N_TYPE | N_EXT); 605 char *jname = strings + sym[j].n_un.n_strx; 606 607 if (((N_SECT | N_EXT) != jn_type && (N_ABS | N_EXT) != jn_type)) 608 continue; 609 610 if (0 == sym[j].n_un.n_strx) /* iff a null, "", name. */ 611 continue; 612 613 if (*jname == '_') 614 jname += 1; 615 616 if (*(unsigned long *)sym[i].n_value <= (unsigned long)sym[j].n_value) 617 continue; 618 619 if ((unsigned long)sym[j].n_value > best) { 620 best = (unsigned long)sym[j].n_value; 621 prev_name = jname; 622 } 623 } 624 625 sdpd->sdpd_func = kmem_alloc((len = strlen(prev_name) + 1), KM_SLEEP); 626 strncpy(sdpd->sdpd_func, prev_name, len); /* NUL termination is ensured. */ 627 628 sdpd->sdpd_offset = *(unsigned long *)sym[i].n_value; 629 630 sdpd->sdpd_next = g_sdt_mach_module.sdt_probes; 631 g_sdt_mach_module.sdt_probes = sdpd; 632 } else { 633 prev_name = name; 634 } 635 } 636 } 637 638 sdt_attach( (dev_info_t *)(uintptr_t)majdevno, DDI_ATTACH ); 639 640 gSDTInited = 1; 641 } else 642 panic("sdt_init: called twice!\n"); 643} 644 645#undef SDT_MAJOR 646 647/*ARGSUSED*/ 648void 649sdt_provide_module(void *arg, struct modctl *ctl) 650{ 651#pragma unused(arg) 652 ASSERT(ctl != NULL); 653 ASSERT(dtrace_kernel_symbol_mode != DTRACE_KERNEL_SYMBOLS_NEVER); 654 lck_mtx_assert(&mod_lock, LCK_MTX_ASSERT_OWNED); 655 656 if (MOD_SDT_DONE(ctl)) 657 return; 658 659 if (MOD_IS_MACH_KERNEL(ctl)) { 660 __sdt_provide_module(arg, &g_sdt_kernctl); 661 662 sdt_probedesc_t *sdpd = g_sdt_mach_module.sdt_probes; 663 while (sdpd) { 664 sdt_probedesc_t *this_sdpd = sdpd; 665 kmem_free((void *)sdpd->sdpd_name, strlen(sdpd->sdpd_name) + 1); 666 kmem_free((void *)sdpd->sdpd_func, strlen(sdpd->sdpd_func) + 1); 667 sdpd = sdpd->sdpd_next; 668 kmem_free((void *)this_sdpd, sizeof(sdt_probedesc_t)); 669 } 670 g_sdt_mach_module.sdt_probes = NULL; 671 } else { 672 /* FIXME -- sdt in kext not yet supported */ 673 } 674 675 /* Need to mark this module as completed */ 676 ctl->mod_flags |= MODCTL_SDT_PROBES_PROVIDED; 677} 678 679#endif /* __APPLE__ */ 680