fasttrap.c revision 287642
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 * Portions Copyright 2010 The FreeBSD Foundation 22 * 23 * $FreeBSD: head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c 287642 2015-09-11 03:06:34Z markj $ 24 */ 25 26/* 27 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 28 * Use is subject to license terms. 29 */ 30 31/* 32 * Copyright (c) 2015, Joyent, Inc. All rights reserved. 33 */ 34 35#include <sys/atomic.h> 36#include <sys/errno.h> 37#include <sys/stat.h> 38#include <sys/modctl.h> 39#include <sys/conf.h> 40#include <sys/systm.h> 41#ifdef illumos 42#include <sys/ddi.h> 43#endif 44#include <sys/sunddi.h> 45#include <sys/cpuvar.h> 46#include <sys/kmem.h> 47#ifdef illumos 48#include <sys/strsubr.h> 49#endif 50#include <sys/fasttrap.h> 51#include <sys/fasttrap_impl.h> 52#include <sys/fasttrap_isa.h> 53#include <sys/dtrace.h> 54#include <sys/dtrace_impl.h> 55#include <sys/sysmacros.h> 56#include <sys/proc.h> 57#include <sys/policy.h> 58#ifdef illumos 59#include <util/qsort.h> 60#endif 61#include <sys/mutex.h> 62#include <sys/kernel.h> 63#ifndef illumos 64#include <sys/dtrace_bsd.h> 65#include <sys/eventhandler.h> 66#include <sys/u8_textprep.h> 67#include <sys/user.h> 68#include <vm/vm.h> 69#include <vm/pmap.h> 70#include <vm/vm_map.h> 71#include <vm/vm_param.h> 72#include <cddl/dev/dtrace/dtrace_cddl.h> 73#endif 74 75/* 76 * User-Land Trap-Based Tracing 77 * ---------------------------- 78 * 79 * The fasttrap provider allows DTrace consumers to instrument any user-level 80 * instruction to gather data; this includes probes with semantic 81 * signifigance like entry and return as well as simple offsets into the 82 * function. While the specific techniques used are very ISA specific, the 83 * methodology is generalizable to any architecture. 84 * 85 * 86 * The General Methodology 87 * ----------------------- 88 * 89 * With the primary goal of tracing every user-land instruction and the 90 * limitation that we can't trust user space so don't want to rely on much 91 * information there, we begin by replacing the instructions we want to trace 92 * with trap instructions. Each instruction we overwrite is saved into a hash 93 * table keyed by process ID and pc address. When we enter the kernel due to 94 * this trap instruction, we need the effects of the replaced instruction to 95 * appear to have occurred before we proceed with the user thread's 96 * execution. 97 * 98 * Each user level thread is represented by a ulwp_t structure which is 99 * always easily accessible through a register. The most basic way to produce 100 * the effects of the instruction we replaced is to copy that instruction out 101 * to a bit of scratch space reserved in the user thread's ulwp_t structure 102 * (a sort of kernel-private thread local storage), set the PC to that 103 * scratch space and single step. When we reenter the kernel after single 104 * stepping the instruction we must then adjust the PC to point to what would 105 * normally be the next instruction. Of course, special care must be taken 106 * for branches and jumps, but these represent such a small fraction of any 107 * instruction set that writing the code to emulate these in the kernel is 108 * not too difficult. 109 * 110 * Return probes may require several tracepoints to trace every return site, 111 * and, conversely, each tracepoint may activate several probes (the entry 112 * and offset 0 probes, for example). To solve this muliplexing problem, 113 * tracepoints contain lists of probes to activate and probes contain lists 114 * of tracepoints to enable. If a probe is activated, it adds its ID to 115 * existing tracepoints or creates new ones as necessary. 116 * 117 * Most probes are activated _before_ the instruction is executed, but return 118 * probes are activated _after_ the effects of the last instruction of the 119 * function are visible. Return probes must be fired _after_ we have 120 * single-stepped the instruction whereas all other probes are fired 121 * beforehand. 122 * 123 * 124 * Lock Ordering 125 * ------------- 126 * 127 * The lock ordering below -- both internally and with respect to the DTrace 128 * framework -- is a little tricky and bears some explanation. Each provider 129 * has a lock (ftp_mtx) that protects its members including reference counts 130 * for enabled probes (ftp_rcount), consumers actively creating probes 131 * (ftp_ccount) and USDT consumers (ftp_mcount); all three prevent a provider 132 * from being freed. A provider is looked up by taking the bucket lock for the 133 * provider hash table, and is returned with its lock held. The provider lock 134 * may be taken in functions invoked by the DTrace framework, but may not be 135 * held while calling functions in the DTrace framework. 136 * 137 * To ensure consistency over multiple calls to the DTrace framework, the 138 * creation lock (ftp_cmtx) should be held. Naturally, the creation lock may 139 * not be taken when holding the provider lock as that would create a cyclic 140 * lock ordering. In situations where one would naturally take the provider 141 * lock and then the creation lock, we instead up a reference count to prevent 142 * the provider from disappearing, drop the provider lock, and acquire the 143 * creation lock. 144 * 145 * Briefly: 146 * bucket lock before provider lock 147 * DTrace before provider lock 148 * creation lock before DTrace 149 * never hold the provider lock and creation lock simultaneously 150 */ 151 152static d_open_t fasttrap_open; 153static d_ioctl_t fasttrap_ioctl; 154 155static struct cdevsw fasttrap_cdevsw = { 156 .d_version = D_VERSION, 157 .d_open = fasttrap_open, 158 .d_ioctl = fasttrap_ioctl, 159 .d_name = "fasttrap", 160}; 161static struct cdev *fasttrap_cdev; 162static dtrace_meta_provider_id_t fasttrap_meta_id; 163 164static struct proc *fasttrap_cleanup_proc; 165static struct mtx fasttrap_cleanup_mtx; 166static uint_t fasttrap_cleanup_work, fasttrap_cleanup_drain, fasttrap_cleanup_cv; 167 168/* 169 * Generation count on modifications to the global tracepoint lookup table. 170 */ 171static volatile uint64_t fasttrap_mod_gen; 172 173/* 174 * When the fasttrap provider is loaded, fasttrap_max is set to either 175 * FASTTRAP_MAX_DEFAULT or the value for fasttrap-max-probes in the 176 * fasttrap.conf file. Each time a probe is created, fasttrap_total is 177 * incremented by the number of tracepoints that may be associated with that 178 * probe; fasttrap_total is capped at fasttrap_max. 179 */ 180#define FASTTRAP_MAX_DEFAULT 250000 181static uint32_t fasttrap_max; 182static uint32_t fasttrap_total; 183 184/* 185 * Copyright (c) 2011, Joyent, Inc. All rights reserved. 186 */ 187 188#define FASTTRAP_TPOINTS_DEFAULT_SIZE 0x4000 189#define FASTTRAP_PROVIDERS_DEFAULT_SIZE 0x100 190#define FASTTRAP_PROCS_DEFAULT_SIZE 0x100 191 192#define FASTTRAP_PID_NAME "pid" 193 194fasttrap_hash_t fasttrap_tpoints; 195static fasttrap_hash_t fasttrap_provs; 196static fasttrap_hash_t fasttrap_procs; 197 198static uint64_t fasttrap_pid_count; /* pid ref count */ 199static kmutex_t fasttrap_count_mtx; /* lock on ref count */ 200 201#define FASTTRAP_ENABLE_FAIL 1 202#define FASTTRAP_ENABLE_PARTIAL 2 203 204static int fasttrap_tracepoint_enable(proc_t *, fasttrap_probe_t *, uint_t); 205static void fasttrap_tracepoint_disable(proc_t *, fasttrap_probe_t *, uint_t); 206 207static fasttrap_provider_t *fasttrap_provider_lookup(pid_t, const char *, 208 const dtrace_pattr_t *); 209static void fasttrap_provider_retire(pid_t, const char *, int); 210static void fasttrap_provider_free(fasttrap_provider_t *); 211 212static fasttrap_proc_t *fasttrap_proc_lookup(pid_t); 213static void fasttrap_proc_release(fasttrap_proc_t *); 214 215#ifndef illumos 216static void fasttrap_thread_dtor(void *, struct thread *); 217#endif 218 219#define FASTTRAP_PROVS_INDEX(pid, name) \ 220 ((fasttrap_hash_str(name) + (pid)) & fasttrap_provs.fth_mask) 221 222#define FASTTRAP_PROCS_INDEX(pid) ((pid) & fasttrap_procs.fth_mask) 223 224#ifndef illumos 225static kmutex_t fasttrap_cpuc_pid_lock[MAXCPU]; 226static eventhandler_tag fasttrap_thread_dtor_tag; 227#endif 228 229static int 230fasttrap_highbit(ulong_t i) 231{ 232 int h = 1; 233 234 if (i == 0) 235 return (0); 236#ifdef _LP64 237 if (i & 0xffffffff00000000ul) { 238 h += 32; i >>= 32; 239 } 240#endif 241 if (i & 0xffff0000) { 242 h += 16; i >>= 16; 243 } 244 if (i & 0xff00) { 245 h += 8; i >>= 8; 246 } 247 if (i & 0xf0) { 248 h += 4; i >>= 4; 249 } 250 if (i & 0xc) { 251 h += 2; i >>= 2; 252 } 253 if (i & 0x2) { 254 h += 1; 255 } 256 return (h); 257} 258 259static uint_t 260fasttrap_hash_str(const char *p) 261{ 262 unsigned int g; 263 uint_t hval = 0; 264 265 while (*p) { 266 hval = (hval << 4) + *p++; 267 if ((g = (hval & 0xf0000000)) != 0) 268 hval ^= g >> 24; 269 hval &= ~g; 270 } 271 return (hval); 272} 273 274void 275fasttrap_sigtrap(proc_t *p, kthread_t *t, uintptr_t pc) 276{ 277#ifdef illumos 278 sigqueue_t *sqp = kmem_zalloc(sizeof (sigqueue_t), KM_SLEEP); 279 280 sqp->sq_info.si_signo = SIGTRAP; 281 sqp->sq_info.si_code = TRAP_DTRACE; 282 sqp->sq_info.si_addr = (caddr_t)pc; 283 284 mutex_enter(&p->p_lock); 285 sigaddqa(p, t, sqp); 286 mutex_exit(&p->p_lock); 287 288 if (t != NULL) 289 aston(t); 290#else 291 ksiginfo_t *ksi = kmem_zalloc(sizeof (ksiginfo_t), KM_SLEEP); 292 293 ksiginfo_init(ksi); 294 ksi->ksi_signo = SIGTRAP; 295 ksi->ksi_code = TRAP_DTRACE; 296 ksi->ksi_addr = (caddr_t)pc; 297 PROC_LOCK(p); 298 (void) tdsendsignal(p, t, SIGTRAP, ksi); 299 PROC_UNLOCK(p); 300#endif 301} 302 303#ifndef illumos 304/* 305 * Obtain a chunk of scratch space in the address space of the target process. 306 */ 307fasttrap_scrspace_t * 308fasttrap_scraddr(struct thread *td, fasttrap_proc_t *fprc) 309{ 310 fasttrap_scrblock_t *scrblk; 311 fasttrap_scrspace_t *scrspc; 312 struct proc *p; 313 vm_offset_t addr; 314 int error, i; 315 316 scrspc = NULL; 317 if (td->t_dtrace_sscr != NULL) { 318 /* If the thread already has scratch space, we're done. */ 319 scrspc = (fasttrap_scrspace_t *)td->t_dtrace_sscr; 320 return (scrspc); 321 } 322 323 p = td->td_proc; 324 325 mutex_enter(&fprc->ftpc_mtx); 326 if (LIST_EMPTY(&fprc->ftpc_fscr)) { 327 /* 328 * No scratch space is available, so we'll map a new scratch 329 * space block into the traced process' address space. 330 */ 331 addr = 0; 332 error = vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr, 333 FASTTRAP_SCRBLOCK_SIZE, 0, VMFS_ANY_SPACE, VM_PROT_ALL, 334 VM_PROT_ALL, 0); 335 if (error != KERN_SUCCESS) 336 goto done; 337 338 scrblk = malloc(sizeof(*scrblk), M_SOLARIS, M_WAITOK); 339 scrblk->ftsb_addr = addr; 340 LIST_INSERT_HEAD(&fprc->ftpc_scrblks, scrblk, ftsb_next); 341 342 /* 343 * Carve the block up into chunks and put them on the free list. 344 */ 345 for (i = 0; 346 i < FASTTRAP_SCRBLOCK_SIZE / FASTTRAP_SCRSPACE_SIZE; i++) { 347 scrspc = malloc(sizeof(*scrspc), M_SOLARIS, M_WAITOK); 348 scrspc->ftss_addr = addr + 349 i * FASTTRAP_SCRSPACE_SIZE; 350 LIST_INSERT_HEAD(&fprc->ftpc_fscr, scrspc, 351 ftss_next); 352 } 353 } 354 355 /* 356 * Take the first scratch chunk off the free list, put it on the 357 * allocated list, and return its address. 358 */ 359 scrspc = LIST_FIRST(&fprc->ftpc_fscr); 360 LIST_REMOVE(scrspc, ftss_next); 361 LIST_INSERT_HEAD(&fprc->ftpc_ascr, scrspc, ftss_next); 362 363 /* 364 * This scratch space is reserved for use by td until the thread exits. 365 */ 366 td->t_dtrace_sscr = scrspc; 367 368done: 369 mutex_exit(&fprc->ftpc_mtx); 370 371 return (scrspc); 372} 373 374/* 375 * Return any allocated per-thread scratch space chunks back to the process' 376 * free list. 377 */ 378static void 379fasttrap_thread_dtor(void *arg __unused, struct thread *td) 380{ 381 fasttrap_bucket_t *bucket; 382 fasttrap_proc_t *fprc; 383 fasttrap_scrspace_t *scrspc; 384 pid_t pid; 385 386 if (td->t_dtrace_sscr == NULL) 387 return; 388 389 pid = td->td_proc->p_pid; 390 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)]; 391 fprc = NULL; 392 393 /* Look up the fasttrap process handle for this process. */ 394 mutex_enter(&bucket->ftb_mtx); 395 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) { 396 if (fprc->ftpc_pid == pid) { 397 mutex_enter(&fprc->ftpc_mtx); 398 mutex_exit(&bucket->ftb_mtx); 399 break; 400 } 401 } 402 if (fprc == NULL) { 403 mutex_exit(&bucket->ftb_mtx); 404 return; 405 } 406 407 scrspc = (fasttrap_scrspace_t *)td->t_dtrace_sscr; 408 LIST_REMOVE(scrspc, ftss_next); 409 LIST_INSERT_HEAD(&fprc->ftpc_fscr, scrspc, ftss_next); 410 411 mutex_exit(&fprc->ftpc_mtx); 412} 413#endif 414 415/* 416 * This function ensures that no threads are actively using the memory 417 * associated with probes that were formerly live. 418 */ 419static void 420fasttrap_mod_barrier(uint64_t gen) 421{ 422 int i; 423 424 if (gen < fasttrap_mod_gen) 425 return; 426 427 fasttrap_mod_gen++; 428 429 CPU_FOREACH(i) { 430 mutex_enter(&fasttrap_cpuc_pid_lock[i]); 431 mutex_exit(&fasttrap_cpuc_pid_lock[i]); 432 } 433} 434 435/* 436 * This function performs asynchronous cleanup of fasttrap providers. The 437 * Solaris implementation of this mechanism use a timeout that's activated in 438 * fasttrap_pid_cleanup(), but this doesn't work in FreeBSD: one may sleep while 439 * holding the DTrace mutexes, but it is unsafe to sleep in a callout handler. 440 * Thus we use a dedicated process to perform the cleanup when requested. 441 */ 442/*ARGSUSED*/ 443static void 444fasttrap_pid_cleanup_cb(void *data) 445{ 446 fasttrap_provider_t **fpp, *fp; 447 fasttrap_bucket_t *bucket; 448 dtrace_provider_id_t provid; 449 int i, later = 0, rval; 450 451 mtx_lock(&fasttrap_cleanup_mtx); 452 while (!fasttrap_cleanup_drain || later > 0) { 453 fasttrap_cleanup_work = 0; 454 mtx_unlock(&fasttrap_cleanup_mtx); 455 456 later = 0; 457 458 /* 459 * Iterate over all the providers trying to remove the marked 460 * ones. If a provider is marked but not retired, we just 461 * have to take a crack at removing it -- it's no big deal if 462 * we can't. 463 */ 464 for (i = 0; i < fasttrap_provs.fth_nent; i++) { 465 bucket = &fasttrap_provs.fth_table[i]; 466 mutex_enter(&bucket->ftb_mtx); 467 fpp = (fasttrap_provider_t **)&bucket->ftb_data; 468 469 while ((fp = *fpp) != NULL) { 470 if (!fp->ftp_marked) { 471 fpp = &fp->ftp_next; 472 continue; 473 } 474 475 mutex_enter(&fp->ftp_mtx); 476 477 /* 478 * If this provider has consumers actively 479 * creating probes (ftp_ccount) or is a USDT 480 * provider (ftp_mcount), we can't unregister 481 * or even condense. 482 */ 483 if (fp->ftp_ccount != 0 || 484 fp->ftp_mcount != 0) { 485 mutex_exit(&fp->ftp_mtx); 486 fp->ftp_marked = 0; 487 continue; 488 } 489 490 if (!fp->ftp_retired || fp->ftp_rcount != 0) 491 fp->ftp_marked = 0; 492 493 mutex_exit(&fp->ftp_mtx); 494 495 /* 496 * If we successfully unregister this 497 * provider we can remove it from the hash 498 * chain and free the memory. If our attempt 499 * to unregister fails and this is a retired 500 * provider, increment our flag to try again 501 * pretty soon. If we've consumed more than 502 * half of our total permitted number of 503 * probes call dtrace_condense() to try to 504 * clean out the unenabled probes. 505 */ 506 provid = fp->ftp_provid; 507 if ((rval = dtrace_unregister(provid)) != 0) { 508 if (fasttrap_total > fasttrap_max / 2) 509 (void) dtrace_condense(provid); 510 511 if (rval == EAGAIN) 512 fp->ftp_marked = 1; 513 514 later += fp->ftp_marked; 515 fpp = &fp->ftp_next; 516 } else { 517 *fpp = fp->ftp_next; 518 fasttrap_provider_free(fp); 519 } 520 } 521 mutex_exit(&bucket->ftb_mtx); 522 } 523 mtx_lock(&fasttrap_cleanup_mtx); 524 525 /* 526 * If we were unable to retire a provider, try again after a 527 * second. This situation can occur in certain circumstances 528 * where providers cannot be unregistered even though they have 529 * no probes enabled because of an execution of dtrace -l or 530 * something similar. 531 */ 532 if (later > 0 || fasttrap_cleanup_work || 533 fasttrap_cleanup_drain) { 534 mtx_unlock(&fasttrap_cleanup_mtx); 535 pause("ftclean", hz); 536 mtx_lock(&fasttrap_cleanup_mtx); 537 } else 538 mtx_sleep(&fasttrap_cleanup_cv, &fasttrap_cleanup_mtx, 539 0, "ftcl", 0); 540 } 541 542 /* 543 * Wake up the thread in fasttrap_unload() now that we're done. 544 */ 545 wakeup(&fasttrap_cleanup_drain); 546 mtx_unlock(&fasttrap_cleanup_mtx); 547 548 kthread_exit(); 549} 550 551/* 552 * Activates the asynchronous cleanup mechanism. 553 */ 554static void 555fasttrap_pid_cleanup(void) 556{ 557 558 mtx_lock(&fasttrap_cleanup_mtx); 559 if (!fasttrap_cleanup_work) { 560 fasttrap_cleanup_work = 1; 561 wakeup(&fasttrap_cleanup_cv); 562 } 563 mtx_unlock(&fasttrap_cleanup_mtx); 564} 565 566/* 567 * This is called from cfork() via dtrace_fasttrap_fork(). The child 568 * process's address space is (roughly) a copy of the parent process's so 569 * we have to remove all the instrumentation we had previously enabled in the 570 * parent. 571 */ 572static void 573fasttrap_fork(proc_t *p, proc_t *cp) 574{ 575#ifndef illumos 576 fasttrap_scrblock_t *scrblk; 577 fasttrap_proc_t *fprc = NULL; 578#endif 579 pid_t ppid = p->p_pid; 580 int i; 581 582#ifdef illumos 583 ASSERT(curproc == p); 584 ASSERT(p->p_proc_flag & P_PR_LOCK); 585#else 586 PROC_LOCK_ASSERT(p, MA_OWNED); 587#endif 588#ifdef illumos 589 ASSERT(p->p_dtrace_count > 0); 590#else 591 if (p->p_dtrace_helpers) { 592 /* 593 * dtrace_helpers_duplicate() allocates memory. 594 */ 595 _PHOLD(cp); 596 PROC_UNLOCK(p); 597 PROC_UNLOCK(cp); 598 dtrace_helpers_duplicate(p, cp); 599 PROC_LOCK(cp); 600 PROC_LOCK(p); 601 _PRELE(cp); 602 } 603 /* 604 * This check is purposely here instead of in kern_fork.c because, 605 * for legal resons, we cannot include the dtrace_cddl.h header 606 * inside kern_fork.c and insert if-clause there. 607 */ 608 if (p->p_dtrace_count == 0) 609 return; 610#endif 611 ASSERT(cp->p_dtrace_count == 0); 612 613 /* 614 * This would be simpler and faster if we maintained per-process 615 * hash tables of enabled tracepoints. It could, however, potentially 616 * slow down execution of a tracepoint since we'd need to go 617 * through two levels of indirection. In the future, we should 618 * consider either maintaining per-process ancillary lists of 619 * enabled tracepoints or hanging a pointer to a per-process hash 620 * table of enabled tracepoints off the proc structure. 621 */ 622 623 /* 624 * We don't have to worry about the child process disappearing 625 * because we're in fork(). 626 */ 627#ifdef illumos 628 mtx_lock_spin(&cp->p_slock); 629 sprlock_proc(cp); 630 mtx_unlock_spin(&cp->p_slock); 631#else 632 /* 633 * fasttrap_tracepoint_remove() expects the child process to be 634 * unlocked and the VM then expects curproc to be unlocked. 635 */ 636 _PHOLD(cp); 637 PROC_UNLOCK(cp); 638 PROC_UNLOCK(p); 639#endif 640 641 /* 642 * Iterate over every tracepoint looking for ones that belong to the 643 * parent process, and remove each from the child process. 644 */ 645 for (i = 0; i < fasttrap_tpoints.fth_nent; i++) { 646 fasttrap_tracepoint_t *tp; 647 fasttrap_bucket_t *bucket = &fasttrap_tpoints.fth_table[i]; 648 649 mutex_enter(&bucket->ftb_mtx); 650 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) { 651 if (tp->ftt_pid == ppid && 652 tp->ftt_proc->ftpc_acount != 0) { 653 int ret = fasttrap_tracepoint_remove(cp, tp); 654 ASSERT(ret == 0); 655 656 /* 657 * The count of active providers can only be 658 * decremented (i.e. to zero) during exec, 659 * exit, and removal of a meta provider so it 660 * should be impossible to drop the count 661 * mid-fork. 662 */ 663 ASSERT(tp->ftt_proc->ftpc_acount != 0); 664#ifndef illumos 665 fprc = tp->ftt_proc; 666#endif 667 } 668 } 669 mutex_exit(&bucket->ftb_mtx); 670 671#ifndef illumos 672 /* 673 * Unmap any scratch space inherited from the parent's address 674 * space. 675 */ 676 if (fprc != NULL) { 677 mutex_enter(&fprc->ftpc_mtx); 678 LIST_FOREACH(scrblk, &fprc->ftpc_scrblks, ftsb_next) { 679 vm_map_remove(&cp->p_vmspace->vm_map, 680 scrblk->ftsb_addr, 681 scrblk->ftsb_addr + FASTTRAP_SCRBLOCK_SIZE); 682 } 683 mutex_exit(&fprc->ftpc_mtx); 684 } 685#endif 686 } 687 688#ifdef illumos 689 mutex_enter(&cp->p_lock); 690 sprunlock(cp); 691#else 692 PROC_LOCK(p); 693 PROC_LOCK(cp); 694 _PRELE(cp); 695#endif 696} 697 698/* 699 * This is called from proc_exit() or from exec_common() if p_dtrace_probes 700 * is set on the proc structure to indicate that there is a pid provider 701 * associated with this process. 702 */ 703static void 704fasttrap_exec_exit(proc_t *p) 705{ 706#ifndef illumos 707 struct thread *td; 708#endif 709 710#ifdef illumos 711 ASSERT(p == curproc); 712#else 713 PROC_LOCK_ASSERT(p, MA_OWNED); 714 _PHOLD(p); 715 /* 716 * Since struct threads may be recycled, we cannot rely on t_dtrace_sscr 717 * fields to be zeroed by kdtrace_thread_ctor. Thus we must zero it 718 * ourselves when a process exits. 719 */ 720 FOREACH_THREAD_IN_PROC(p, td) 721 td->t_dtrace_sscr = NULL; 722 PROC_UNLOCK(p); 723#endif 724 725 /* 726 * We clean up the pid provider for this process here; user-land 727 * static probes are handled by the meta-provider remove entry point. 728 */ 729 fasttrap_provider_retire(p->p_pid, FASTTRAP_PID_NAME, 0); 730#ifndef illumos 731 if (p->p_dtrace_helpers) 732 dtrace_helpers_destroy(p); 733 PROC_LOCK(p); 734 _PRELE(p); 735#endif 736} 737 738 739/*ARGSUSED*/ 740static void 741fasttrap_pid_provide(void *arg, dtrace_probedesc_t *desc) 742{ 743 /* 744 * There are no "default" pid probes. 745 */ 746} 747 748static int 749fasttrap_tracepoint_enable(proc_t *p, fasttrap_probe_t *probe, uint_t index) 750{ 751 fasttrap_tracepoint_t *tp, *new_tp = NULL; 752 fasttrap_bucket_t *bucket; 753 fasttrap_id_t *id; 754 pid_t pid; 755 uintptr_t pc; 756 757 ASSERT(index < probe->ftp_ntps); 758 759 pid = probe->ftp_pid; 760 pc = probe->ftp_tps[index].fit_tp->ftt_pc; 761 id = &probe->ftp_tps[index].fit_id; 762 763 ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid); 764 765#ifdef illumos 766 ASSERT(!(p->p_flag & SVFORK)); 767#endif 768 769 /* 770 * Before we make any modifications, make sure we've imposed a barrier 771 * on the generation in which this probe was last modified. 772 */ 773 fasttrap_mod_barrier(probe->ftp_gen); 774 775 bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; 776 777 /* 778 * If the tracepoint has already been enabled, just add our id to the 779 * list of interested probes. This may be our second time through 780 * this path in which case we'll have constructed the tracepoint we'd 781 * like to install. If we can't find a match, and have an allocated 782 * tracepoint ready to go, enable that one now. 783 * 784 * A tracepoint whose process is defunct is also considered defunct. 785 */ 786again: 787 mutex_enter(&bucket->ftb_mtx); 788 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) { 789 /* 790 * Note that it's safe to access the active count on the 791 * associated proc structure because we know that at least one 792 * provider (this one) will still be around throughout this 793 * operation. 794 */ 795 if (tp->ftt_pid != pid || tp->ftt_pc != pc || 796 tp->ftt_proc->ftpc_acount == 0) 797 continue; 798 799 /* 800 * Now that we've found a matching tracepoint, it would be 801 * a decent idea to confirm that the tracepoint is still 802 * enabled and the trap instruction hasn't been overwritten. 803 * Since this is a little hairy, we'll punt for now. 804 */ 805 806 /* 807 * This can't be the first interested probe. We don't have 808 * to worry about another thread being in the midst of 809 * deleting this tracepoint (which would be the only valid 810 * reason for a tracepoint to have no interested probes) 811 * since we're holding P_PR_LOCK for this process. 812 */ 813 ASSERT(tp->ftt_ids != NULL || tp->ftt_retids != NULL); 814 815 switch (id->fti_ptype) { 816 case DTFTP_ENTRY: 817 case DTFTP_OFFSETS: 818 case DTFTP_IS_ENABLED: 819 id->fti_next = tp->ftt_ids; 820 membar_producer(); 821 tp->ftt_ids = id; 822 membar_producer(); 823 break; 824 825 case DTFTP_RETURN: 826 case DTFTP_POST_OFFSETS: 827 id->fti_next = tp->ftt_retids; 828 membar_producer(); 829 tp->ftt_retids = id; 830 membar_producer(); 831 break; 832 833 default: 834 ASSERT(0); 835 } 836 837 mutex_exit(&bucket->ftb_mtx); 838 839 if (new_tp != NULL) { 840 new_tp->ftt_ids = NULL; 841 new_tp->ftt_retids = NULL; 842 } 843 844 return (0); 845 } 846 847 /* 848 * If we have a good tracepoint ready to go, install it now while 849 * we have the lock held and no one can screw with us. 850 */ 851 if (new_tp != NULL) { 852 int rc = 0; 853 854 new_tp->ftt_next = bucket->ftb_data; 855 membar_producer(); 856 bucket->ftb_data = new_tp; 857 membar_producer(); 858 mutex_exit(&bucket->ftb_mtx); 859 860 /* 861 * Activate the tracepoint in the ISA-specific manner. 862 * If this fails, we need to report the failure, but 863 * indicate that this tracepoint must still be disabled 864 * by calling fasttrap_tracepoint_disable(). 865 */ 866 if (fasttrap_tracepoint_install(p, new_tp) != 0) 867 rc = FASTTRAP_ENABLE_PARTIAL; 868 869 /* 870 * Increment the count of the number of tracepoints active in 871 * the victim process. 872 */ 873#ifdef illumos 874 ASSERT(p->p_proc_flag & P_PR_LOCK); 875#endif 876 p->p_dtrace_count++; 877 878 return (rc); 879 } 880 881 mutex_exit(&bucket->ftb_mtx); 882 883 /* 884 * Initialize the tracepoint that's been preallocated with the probe. 885 */ 886 new_tp = probe->ftp_tps[index].fit_tp; 887 888 ASSERT(new_tp->ftt_pid == pid); 889 ASSERT(new_tp->ftt_pc == pc); 890 ASSERT(new_tp->ftt_proc == probe->ftp_prov->ftp_proc); 891 ASSERT(new_tp->ftt_ids == NULL); 892 ASSERT(new_tp->ftt_retids == NULL); 893 894 switch (id->fti_ptype) { 895 case DTFTP_ENTRY: 896 case DTFTP_OFFSETS: 897 case DTFTP_IS_ENABLED: 898 id->fti_next = NULL; 899 new_tp->ftt_ids = id; 900 break; 901 902 case DTFTP_RETURN: 903 case DTFTP_POST_OFFSETS: 904 id->fti_next = NULL; 905 new_tp->ftt_retids = id; 906 break; 907 908 default: 909 ASSERT(0); 910 } 911 912 /* 913 * If the ISA-dependent initialization goes to plan, go back to the 914 * beginning and try to install this freshly made tracepoint. 915 */ 916 if (fasttrap_tracepoint_init(p, new_tp, pc, id->fti_ptype) == 0) 917 goto again; 918 919 new_tp->ftt_ids = NULL; 920 new_tp->ftt_retids = NULL; 921 922 return (FASTTRAP_ENABLE_FAIL); 923} 924 925static void 926fasttrap_tracepoint_disable(proc_t *p, fasttrap_probe_t *probe, uint_t index) 927{ 928 fasttrap_bucket_t *bucket; 929 fasttrap_provider_t *provider = probe->ftp_prov; 930 fasttrap_tracepoint_t **pp, *tp; 931 fasttrap_id_t *id, **idp = NULL; 932 pid_t pid; 933 uintptr_t pc; 934 935 ASSERT(index < probe->ftp_ntps); 936 937 pid = probe->ftp_pid; 938 pc = probe->ftp_tps[index].fit_tp->ftt_pc; 939 id = &probe->ftp_tps[index].fit_id; 940 941 ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid); 942 943 /* 944 * Find the tracepoint and make sure that our id is one of the 945 * ones registered with it. 946 */ 947 bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; 948 mutex_enter(&bucket->ftb_mtx); 949 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) { 950 if (tp->ftt_pid == pid && tp->ftt_pc == pc && 951 tp->ftt_proc == provider->ftp_proc) 952 break; 953 } 954 955 /* 956 * If we somehow lost this tracepoint, we're in a world of hurt. 957 */ 958 ASSERT(tp != NULL); 959 960 switch (id->fti_ptype) { 961 case DTFTP_ENTRY: 962 case DTFTP_OFFSETS: 963 case DTFTP_IS_ENABLED: 964 ASSERT(tp->ftt_ids != NULL); 965 idp = &tp->ftt_ids; 966 break; 967 968 case DTFTP_RETURN: 969 case DTFTP_POST_OFFSETS: 970 ASSERT(tp->ftt_retids != NULL); 971 idp = &tp->ftt_retids; 972 break; 973 974 default: 975 ASSERT(0); 976 } 977 978 while ((*idp)->fti_probe != probe) { 979 idp = &(*idp)->fti_next; 980 ASSERT(*idp != NULL); 981 } 982 983 id = *idp; 984 *idp = id->fti_next; 985 membar_producer(); 986 987 ASSERT(id->fti_probe == probe); 988 989 /* 990 * If there are other registered enablings of this tracepoint, we're 991 * all done, but if this was the last probe assocated with this 992 * this tracepoint, we need to remove and free it. 993 */ 994 if (tp->ftt_ids != NULL || tp->ftt_retids != NULL) { 995 996 /* 997 * If the current probe's tracepoint is in use, swap it 998 * for an unused tracepoint. 999 */ 1000 if (tp == probe->ftp_tps[index].fit_tp) { 1001 fasttrap_probe_t *tmp_probe; 1002 fasttrap_tracepoint_t **tmp_tp; 1003 uint_t tmp_index; 1004 1005 if (tp->ftt_ids != NULL) { 1006 tmp_probe = tp->ftt_ids->fti_probe; 1007 /* LINTED - alignment */ 1008 tmp_index = FASTTRAP_ID_INDEX(tp->ftt_ids); 1009 tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp; 1010 } else { 1011 tmp_probe = tp->ftt_retids->fti_probe; 1012 /* LINTED - alignment */ 1013 tmp_index = FASTTRAP_ID_INDEX(tp->ftt_retids); 1014 tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp; 1015 } 1016 1017 ASSERT(*tmp_tp != NULL); 1018 ASSERT(*tmp_tp != probe->ftp_tps[index].fit_tp); 1019 ASSERT((*tmp_tp)->ftt_ids == NULL); 1020 ASSERT((*tmp_tp)->ftt_retids == NULL); 1021 1022 probe->ftp_tps[index].fit_tp = *tmp_tp; 1023 *tmp_tp = tp; 1024 } 1025 1026 mutex_exit(&bucket->ftb_mtx); 1027 1028 /* 1029 * Tag the modified probe with the generation in which it was 1030 * changed. 1031 */ 1032 probe->ftp_gen = fasttrap_mod_gen; 1033 return; 1034 } 1035 1036 mutex_exit(&bucket->ftb_mtx); 1037 1038 /* 1039 * We can't safely remove the tracepoint from the set of active 1040 * tracepoints until we've actually removed the fasttrap instruction 1041 * from the process's text. We can, however, operate on this 1042 * tracepoint secure in the knowledge that no other thread is going to 1043 * be looking at it since we hold P_PR_LOCK on the process if it's 1044 * live or we hold the provider lock on the process if it's dead and 1045 * gone. 1046 */ 1047 1048 /* 1049 * We only need to remove the actual instruction if we're looking 1050 * at an existing process 1051 */ 1052 if (p != NULL) { 1053 /* 1054 * If we fail to restore the instruction we need to kill 1055 * this process since it's in a completely unrecoverable 1056 * state. 1057 */ 1058 if (fasttrap_tracepoint_remove(p, tp) != 0) 1059 fasttrap_sigtrap(p, NULL, pc); 1060 1061 /* 1062 * Decrement the count of the number of tracepoints active 1063 * in the victim process. 1064 */ 1065#ifdef illumos 1066 ASSERT(p->p_proc_flag & P_PR_LOCK); 1067#endif 1068 p->p_dtrace_count--; 1069 } 1070 1071 /* 1072 * Remove the probe from the hash table of active tracepoints. 1073 */ 1074 mutex_enter(&bucket->ftb_mtx); 1075 pp = (fasttrap_tracepoint_t **)&bucket->ftb_data; 1076 ASSERT(*pp != NULL); 1077 while (*pp != tp) { 1078 pp = &(*pp)->ftt_next; 1079 ASSERT(*pp != NULL); 1080 } 1081 1082 *pp = tp->ftt_next; 1083 membar_producer(); 1084 1085 mutex_exit(&bucket->ftb_mtx); 1086 1087 /* 1088 * Tag the modified probe with the generation in which it was changed. 1089 */ 1090 probe->ftp_gen = fasttrap_mod_gen; 1091} 1092 1093static void 1094fasttrap_enable_callbacks(void) 1095{ 1096 /* 1097 * We don't have to play the rw lock game here because we're 1098 * providing something rather than taking something away -- 1099 * we can be sure that no threads have tried to follow this 1100 * function pointer yet. 1101 */ 1102 mutex_enter(&fasttrap_count_mtx); 1103 if (fasttrap_pid_count == 0) { 1104 ASSERT(dtrace_pid_probe_ptr == NULL); 1105 ASSERT(dtrace_return_probe_ptr == NULL); 1106 dtrace_pid_probe_ptr = &fasttrap_pid_probe; 1107 dtrace_return_probe_ptr = &fasttrap_return_probe; 1108 } 1109 ASSERT(dtrace_pid_probe_ptr == &fasttrap_pid_probe); 1110 ASSERT(dtrace_return_probe_ptr == &fasttrap_return_probe); 1111 fasttrap_pid_count++; 1112 mutex_exit(&fasttrap_count_mtx); 1113} 1114 1115static void 1116fasttrap_disable_callbacks(void) 1117{ 1118#ifdef illumos 1119 ASSERT(MUTEX_HELD(&cpu_lock)); 1120#endif 1121 1122 1123 mutex_enter(&fasttrap_count_mtx); 1124 ASSERT(fasttrap_pid_count > 0); 1125 fasttrap_pid_count--; 1126 if (fasttrap_pid_count == 0) { 1127#ifdef illumos 1128 cpu_t *cur, *cpu = CPU; 1129 1130 for (cur = cpu->cpu_next_onln; cur != cpu; 1131 cur = cur->cpu_next_onln) { 1132 rw_enter(&cur->cpu_ft_lock, RW_WRITER); 1133 } 1134#endif 1135 dtrace_pid_probe_ptr = NULL; 1136 dtrace_return_probe_ptr = NULL; 1137#ifdef illumos 1138 for (cur = cpu->cpu_next_onln; cur != cpu; 1139 cur = cur->cpu_next_onln) { 1140 rw_exit(&cur->cpu_ft_lock); 1141 } 1142#endif 1143 } 1144 mutex_exit(&fasttrap_count_mtx); 1145} 1146 1147/*ARGSUSED*/ 1148static void 1149fasttrap_pid_enable(void *arg, dtrace_id_t id, void *parg) 1150{ 1151 fasttrap_probe_t *probe = parg; 1152 proc_t *p = NULL; 1153 int i, rc; 1154 1155 ASSERT(probe != NULL); 1156 ASSERT(!probe->ftp_enabled); 1157 ASSERT(id == probe->ftp_id); 1158#ifdef illumos 1159 ASSERT(MUTEX_HELD(&cpu_lock)); 1160#endif 1161 1162 /* 1163 * Increment the count of enabled probes on this probe's provider; 1164 * the provider can't go away while the probe still exists. We 1165 * must increment this even if we aren't able to properly enable 1166 * this probe. 1167 */ 1168 mutex_enter(&probe->ftp_prov->ftp_mtx); 1169 probe->ftp_prov->ftp_rcount++; 1170 mutex_exit(&probe->ftp_prov->ftp_mtx); 1171 1172 /* 1173 * If this probe's provider is retired (meaning it was valid in a 1174 * previously exec'ed incarnation of this address space), bail out. The 1175 * provider can't go away while we're in this code path. 1176 */ 1177 if (probe->ftp_prov->ftp_retired) 1178 return; 1179 1180 /* 1181 * If we can't find the process, it may be that we're in the context of 1182 * a fork in which the traced process is being born and we're copying 1183 * USDT probes. Otherwise, the process is gone so bail. 1184 */ 1185#ifdef illumos 1186 if ((p = sprlock(probe->ftp_pid)) == NULL) { 1187 if ((curproc->p_flag & SFORKING) == 0) 1188 return; 1189 1190 mutex_enter(&pidlock); 1191 p = prfind(probe->ftp_pid); 1192 1193 if (p == NULL) { 1194 /* 1195 * So it's not that the target process is being born, 1196 * it's that it isn't there at all (and we simply 1197 * happen to be forking). Anyway, we know that the 1198 * target is definitely gone, so bail out. 1199 */ 1200 mutex_exit(&pidlock); 1201 return (0); 1202 } 1203 1204 /* 1205 * Confirm that curproc is indeed forking the process in which 1206 * we're trying to enable probes. 1207 */ 1208 ASSERT(p->p_parent == curproc); 1209 ASSERT(p->p_stat == SIDL); 1210 1211 mutex_enter(&p->p_lock); 1212 mutex_exit(&pidlock); 1213 1214 sprlock_proc(p); 1215 } 1216 1217 ASSERT(!(p->p_flag & SVFORK)); 1218 mutex_exit(&p->p_lock); 1219#else 1220 if ((p = pfind(probe->ftp_pid)) == NULL) 1221 return; 1222#endif 1223 1224 /* 1225 * We have to enable the trap entry point before any user threads have 1226 * the chance to execute the trap instruction we're about to place 1227 * in their process's text. 1228 */ 1229#ifdef __FreeBSD__ 1230 /* 1231 * pfind() returns a locked process. 1232 */ 1233 _PHOLD(p); 1234 PROC_UNLOCK(p); 1235#endif 1236 fasttrap_enable_callbacks(); 1237 1238 /* 1239 * Enable all the tracepoints and add this probe's id to each 1240 * tracepoint's list of active probes. 1241 */ 1242 for (i = 0; i < probe->ftp_ntps; i++) { 1243 if ((rc = fasttrap_tracepoint_enable(p, probe, i)) != 0) { 1244 /* 1245 * If enabling the tracepoint failed completely, 1246 * we don't have to disable it; if the failure 1247 * was only partial we must disable it. 1248 */ 1249 if (rc == FASTTRAP_ENABLE_FAIL) 1250 i--; 1251 else 1252 ASSERT(rc == FASTTRAP_ENABLE_PARTIAL); 1253 1254 /* 1255 * Back up and pull out all the tracepoints we've 1256 * created so far for this probe. 1257 */ 1258 while (i >= 0) { 1259 fasttrap_tracepoint_disable(p, probe, i); 1260 i--; 1261 } 1262 1263#ifdef illumos 1264 mutex_enter(&p->p_lock); 1265 sprunlock(p); 1266#else 1267 PRELE(p); 1268#endif 1269 1270 /* 1271 * Since we're not actually enabling this probe, 1272 * drop our reference on the trap table entry. 1273 */ 1274 fasttrap_disable_callbacks(); 1275 return; 1276 } 1277 } 1278#ifdef illumos 1279 mutex_enter(&p->p_lock); 1280 sprunlock(p); 1281#else 1282 PRELE(p); 1283#endif 1284 1285 probe->ftp_enabled = 1; 1286} 1287 1288/*ARGSUSED*/ 1289static void 1290fasttrap_pid_disable(void *arg, dtrace_id_t id, void *parg) 1291{ 1292 fasttrap_probe_t *probe = parg; 1293 fasttrap_provider_t *provider = probe->ftp_prov; 1294 proc_t *p; 1295 int i, whack = 0; 1296 1297 ASSERT(id == probe->ftp_id); 1298 1299 mutex_enter(&provider->ftp_mtx); 1300 1301 /* 1302 * We won't be able to acquire a /proc-esque lock on the process 1303 * iff the process is dead and gone. In this case, we rely on the 1304 * provider lock as a point of mutual exclusion to prevent other 1305 * DTrace consumers from disabling this probe. 1306 */ 1307 if ((p = pfind(probe->ftp_pid)) != NULL) { 1308#ifdef __FreeBSD__ 1309 if (p->p_flag & P_WEXIT) { 1310 PROC_UNLOCK(p); 1311 p = NULL; 1312 } else { 1313 _PHOLD(p); 1314 PROC_UNLOCK(p); 1315 } 1316#endif 1317 } 1318 1319 /* 1320 * Disable all the associated tracepoints (for fully enabled probes). 1321 */ 1322 if (probe->ftp_enabled) { 1323 for (i = 0; i < probe->ftp_ntps; i++) { 1324 fasttrap_tracepoint_disable(p, probe, i); 1325 } 1326 } 1327 1328 ASSERT(provider->ftp_rcount > 0); 1329 provider->ftp_rcount--; 1330 1331 if (p != NULL) { 1332 /* 1333 * Even though we may not be able to remove it entirely, we 1334 * mark this retired provider to get a chance to remove some 1335 * of the associated probes. 1336 */ 1337 if (provider->ftp_retired && !provider->ftp_marked) 1338 whack = provider->ftp_marked = 1; 1339 mutex_exit(&provider->ftp_mtx); 1340 } else { 1341 /* 1342 * If the process is dead, we're just waiting for the 1343 * last probe to be disabled to be able to free it. 1344 */ 1345 if (provider->ftp_rcount == 0 && !provider->ftp_marked) 1346 whack = provider->ftp_marked = 1; 1347 mutex_exit(&provider->ftp_mtx); 1348 } 1349 1350 if (whack) 1351 fasttrap_pid_cleanup(); 1352 1353#ifdef __FreeBSD__ 1354 if (p != NULL) 1355 PRELE(p); 1356#endif 1357 if (!probe->ftp_enabled) 1358 return; 1359 1360 probe->ftp_enabled = 0; 1361 1362#ifdef illumos 1363 ASSERT(MUTEX_HELD(&cpu_lock)); 1364#endif 1365 fasttrap_disable_callbacks(); 1366} 1367 1368/*ARGSUSED*/ 1369static void 1370fasttrap_pid_getargdesc(void *arg, dtrace_id_t id, void *parg, 1371 dtrace_argdesc_t *desc) 1372{ 1373 fasttrap_probe_t *probe = parg; 1374 char *str; 1375 int i, ndx; 1376 1377 desc->dtargd_native[0] = '\0'; 1378 desc->dtargd_xlate[0] = '\0'; 1379 1380 if (probe->ftp_prov->ftp_retired != 0 || 1381 desc->dtargd_ndx >= probe->ftp_nargs) { 1382 desc->dtargd_ndx = DTRACE_ARGNONE; 1383 return; 1384 } 1385 1386 ndx = (probe->ftp_argmap != NULL) ? 1387 probe->ftp_argmap[desc->dtargd_ndx] : desc->dtargd_ndx; 1388 1389 str = probe->ftp_ntypes; 1390 for (i = 0; i < ndx; i++) { 1391 str += strlen(str) + 1; 1392 } 1393 1394 ASSERT(strlen(str + 1) < sizeof (desc->dtargd_native)); 1395 (void) strcpy(desc->dtargd_native, str); 1396 1397 if (probe->ftp_xtypes == NULL) 1398 return; 1399 1400 str = probe->ftp_xtypes; 1401 for (i = 0; i < desc->dtargd_ndx; i++) { 1402 str += strlen(str) + 1; 1403 } 1404 1405 ASSERT(strlen(str + 1) < sizeof (desc->dtargd_xlate)); 1406 (void) strcpy(desc->dtargd_xlate, str); 1407} 1408 1409/*ARGSUSED*/ 1410static void 1411fasttrap_pid_destroy(void *arg, dtrace_id_t id, void *parg) 1412{ 1413 fasttrap_probe_t *probe = parg; 1414 int i; 1415 size_t size; 1416 1417 ASSERT(probe != NULL); 1418 ASSERT(!probe->ftp_enabled); 1419 ASSERT(fasttrap_total >= probe->ftp_ntps); 1420 1421 atomic_add_32(&fasttrap_total, -probe->ftp_ntps); 1422 size = offsetof(fasttrap_probe_t, ftp_tps[probe->ftp_ntps]); 1423 1424 if (probe->ftp_gen + 1 >= fasttrap_mod_gen) 1425 fasttrap_mod_barrier(probe->ftp_gen); 1426 1427 for (i = 0; i < probe->ftp_ntps; i++) { 1428 kmem_free(probe->ftp_tps[i].fit_tp, 1429 sizeof (fasttrap_tracepoint_t)); 1430 } 1431 1432 kmem_free(probe, size); 1433} 1434 1435 1436static const dtrace_pattr_t pid_attr = { 1437{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA }, 1438{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, 1439{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, 1440{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA }, 1441{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, 1442}; 1443 1444static dtrace_pops_t pid_pops = { 1445 fasttrap_pid_provide, 1446 NULL, 1447 fasttrap_pid_enable, 1448 fasttrap_pid_disable, 1449 NULL, 1450 NULL, 1451 fasttrap_pid_getargdesc, 1452 fasttrap_pid_getarg, 1453 NULL, 1454 fasttrap_pid_destroy 1455}; 1456 1457static dtrace_pops_t usdt_pops = { 1458 fasttrap_pid_provide, 1459 NULL, 1460 fasttrap_pid_enable, 1461 fasttrap_pid_disable, 1462 NULL, 1463 NULL, 1464 fasttrap_pid_getargdesc, 1465 fasttrap_usdt_getarg, 1466 NULL, 1467 fasttrap_pid_destroy 1468}; 1469 1470static fasttrap_proc_t * 1471fasttrap_proc_lookup(pid_t pid) 1472{ 1473 fasttrap_bucket_t *bucket; 1474 fasttrap_proc_t *fprc, *new_fprc; 1475 1476 1477 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)]; 1478 mutex_enter(&bucket->ftb_mtx); 1479 1480 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) { 1481 if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) { 1482 mutex_enter(&fprc->ftpc_mtx); 1483 mutex_exit(&bucket->ftb_mtx); 1484 fprc->ftpc_rcount++; 1485 atomic_inc_64(&fprc->ftpc_acount); 1486 ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount); 1487 mutex_exit(&fprc->ftpc_mtx); 1488 1489 return (fprc); 1490 } 1491 } 1492 1493 /* 1494 * Drop the bucket lock so we don't try to perform a sleeping 1495 * allocation under it. 1496 */ 1497 mutex_exit(&bucket->ftb_mtx); 1498 1499 new_fprc = kmem_zalloc(sizeof (fasttrap_proc_t), KM_SLEEP); 1500 new_fprc->ftpc_pid = pid; 1501 new_fprc->ftpc_rcount = 1; 1502 new_fprc->ftpc_acount = 1; 1503#ifndef illumos 1504 mutex_init(&new_fprc->ftpc_mtx, "fasttrap proc mtx", MUTEX_DEFAULT, 1505 NULL); 1506#endif 1507 1508 mutex_enter(&bucket->ftb_mtx); 1509 1510 /* 1511 * Take another lap through the list to make sure a proc hasn't 1512 * been created for this pid while we weren't under the bucket lock. 1513 */ 1514 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) { 1515 if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) { 1516 mutex_enter(&fprc->ftpc_mtx); 1517 mutex_exit(&bucket->ftb_mtx); 1518 fprc->ftpc_rcount++; 1519 atomic_inc_64(&fprc->ftpc_acount); 1520 ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount); 1521 mutex_exit(&fprc->ftpc_mtx); 1522 1523 kmem_free(new_fprc, sizeof (fasttrap_proc_t)); 1524 1525 return (fprc); 1526 } 1527 } 1528 1529 new_fprc->ftpc_next = bucket->ftb_data; 1530 bucket->ftb_data = new_fprc; 1531 1532 mutex_exit(&bucket->ftb_mtx); 1533 1534 return (new_fprc); 1535} 1536 1537static void 1538fasttrap_proc_release(fasttrap_proc_t *proc) 1539{ 1540 fasttrap_bucket_t *bucket; 1541 fasttrap_proc_t *fprc, **fprcp; 1542 pid_t pid = proc->ftpc_pid; 1543#ifndef illumos 1544 fasttrap_scrblock_t *scrblk, *scrblktmp; 1545 fasttrap_scrspace_t *scrspc, *scrspctmp; 1546 struct proc *p; 1547 struct thread *td; 1548#endif 1549 1550 mutex_enter(&proc->ftpc_mtx); 1551 1552 ASSERT(proc->ftpc_rcount != 0); 1553 ASSERT(proc->ftpc_acount <= proc->ftpc_rcount); 1554 1555 if (--proc->ftpc_rcount != 0) { 1556 mutex_exit(&proc->ftpc_mtx); 1557 return; 1558 } 1559 1560#ifndef illumos 1561 /* 1562 * Free all structures used to manage per-thread scratch space. 1563 */ 1564 LIST_FOREACH_SAFE(scrblk, &proc->ftpc_scrblks, ftsb_next, 1565 scrblktmp) { 1566 LIST_REMOVE(scrblk, ftsb_next); 1567 free(scrblk, M_SOLARIS); 1568 } 1569 LIST_FOREACH_SAFE(scrspc, &proc->ftpc_fscr, ftss_next, scrspctmp) { 1570 LIST_REMOVE(scrspc, ftss_next); 1571 free(scrspc, M_SOLARIS); 1572 } 1573 LIST_FOREACH_SAFE(scrspc, &proc->ftpc_ascr, ftss_next, scrspctmp) { 1574 LIST_REMOVE(scrspc, ftss_next); 1575 free(scrspc, M_SOLARIS); 1576 } 1577 1578 if ((p = pfind(pid)) != NULL) { 1579 FOREACH_THREAD_IN_PROC(p, td) 1580 td->t_dtrace_sscr = NULL; 1581 PROC_UNLOCK(p); 1582 } 1583#endif 1584 1585 mutex_exit(&proc->ftpc_mtx); 1586 1587 /* 1588 * There should definitely be no live providers associated with this 1589 * process at this point. 1590 */ 1591 ASSERT(proc->ftpc_acount == 0); 1592 1593 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)]; 1594 mutex_enter(&bucket->ftb_mtx); 1595 1596 fprcp = (fasttrap_proc_t **)&bucket->ftb_data; 1597 while ((fprc = *fprcp) != NULL) { 1598 if (fprc == proc) 1599 break; 1600 1601 fprcp = &fprc->ftpc_next; 1602 } 1603 1604 /* 1605 * Something strange has happened if we can't find the proc. 1606 */ 1607 ASSERT(fprc != NULL); 1608 1609 *fprcp = fprc->ftpc_next; 1610 1611 mutex_exit(&bucket->ftb_mtx); 1612 1613 kmem_free(fprc, sizeof (fasttrap_proc_t)); 1614} 1615 1616/* 1617 * Lookup a fasttrap-managed provider based on its name and associated pid. 1618 * If the pattr argument is non-NULL, this function instantiates the provider 1619 * if it doesn't exist otherwise it returns NULL. The provider is returned 1620 * with its lock held. 1621 */ 1622static fasttrap_provider_t * 1623fasttrap_provider_lookup(pid_t pid, const char *name, 1624 const dtrace_pattr_t *pattr) 1625{ 1626 fasttrap_provider_t *fp, *new_fp = NULL; 1627 fasttrap_bucket_t *bucket; 1628 char provname[DTRACE_PROVNAMELEN]; 1629 proc_t *p; 1630 cred_t *cred; 1631 1632 ASSERT(strlen(name) < sizeof (fp->ftp_name)); 1633 ASSERT(pattr != NULL); 1634 1635 bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)]; 1636 mutex_enter(&bucket->ftb_mtx); 1637 1638 /* 1639 * Take a lap through the list and return the match if we find it. 1640 */ 1641 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) { 1642 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 && 1643 !fp->ftp_retired) { 1644 mutex_enter(&fp->ftp_mtx); 1645 mutex_exit(&bucket->ftb_mtx); 1646 return (fp); 1647 } 1648 } 1649 1650 /* 1651 * Drop the bucket lock so we don't try to perform a sleeping 1652 * allocation under it. 1653 */ 1654 mutex_exit(&bucket->ftb_mtx); 1655 1656 /* 1657 * Make sure the process exists, isn't a child created as the result 1658 * of a vfork(2), and isn't a zombie (but may be in fork). 1659 */ 1660 if ((p = pfind(pid)) == NULL) 1661 return (NULL); 1662 1663 /* 1664 * Increment p_dtrace_probes so that the process knows to inform us 1665 * when it exits or execs. fasttrap_provider_free() decrements this 1666 * when we're done with this provider. 1667 */ 1668 p->p_dtrace_probes++; 1669 1670 /* 1671 * Grab the credentials for this process so we have 1672 * something to pass to dtrace_register(). 1673 */ 1674 PROC_LOCK_ASSERT(p, MA_OWNED); 1675 crhold(p->p_ucred); 1676 cred = p->p_ucred; 1677 PROC_UNLOCK(p); 1678 1679 new_fp = kmem_zalloc(sizeof (fasttrap_provider_t), KM_SLEEP); 1680 new_fp->ftp_pid = pid; 1681 new_fp->ftp_proc = fasttrap_proc_lookup(pid); 1682#ifndef illumos 1683 mutex_init(&new_fp->ftp_mtx, "provider mtx", MUTEX_DEFAULT, NULL); 1684 mutex_init(&new_fp->ftp_cmtx, "lock on creating", MUTEX_DEFAULT, NULL); 1685#endif 1686 1687 ASSERT(new_fp->ftp_proc != NULL); 1688 1689 mutex_enter(&bucket->ftb_mtx); 1690 1691 /* 1692 * Take another lap through the list to make sure a provider hasn't 1693 * been created for this pid while we weren't under the bucket lock. 1694 */ 1695 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) { 1696 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 && 1697 !fp->ftp_retired) { 1698 mutex_enter(&fp->ftp_mtx); 1699 mutex_exit(&bucket->ftb_mtx); 1700 fasttrap_provider_free(new_fp); 1701 crfree(cred); 1702 return (fp); 1703 } 1704 } 1705 1706 (void) strcpy(new_fp->ftp_name, name); 1707 1708 /* 1709 * Fail and return NULL if either the provider name is too long 1710 * or we fail to register this new provider with the DTrace 1711 * framework. Note that this is the only place we ever construct 1712 * the full provider name -- we keep it in pieces in the provider 1713 * structure. 1714 */ 1715 if (snprintf(provname, sizeof (provname), "%s%u", name, (uint_t)pid) >= 1716 sizeof (provname) || 1717 dtrace_register(provname, pattr, 1718 DTRACE_PRIV_PROC | DTRACE_PRIV_OWNER | DTRACE_PRIV_ZONEOWNER, cred, 1719 pattr == &pid_attr ? &pid_pops : &usdt_pops, new_fp, 1720 &new_fp->ftp_provid) != 0) { 1721 mutex_exit(&bucket->ftb_mtx); 1722 fasttrap_provider_free(new_fp); 1723 crfree(cred); 1724 return (NULL); 1725 } 1726 1727 new_fp->ftp_next = bucket->ftb_data; 1728 bucket->ftb_data = new_fp; 1729 1730 mutex_enter(&new_fp->ftp_mtx); 1731 mutex_exit(&bucket->ftb_mtx); 1732 1733 crfree(cred); 1734 return (new_fp); 1735} 1736 1737static void 1738fasttrap_provider_free(fasttrap_provider_t *provider) 1739{ 1740 pid_t pid = provider->ftp_pid; 1741 proc_t *p; 1742 1743 /* 1744 * There need to be no associated enabled probes, no consumers 1745 * creating probes, and no meta providers referencing this provider. 1746 */ 1747 ASSERT(provider->ftp_rcount == 0); 1748 ASSERT(provider->ftp_ccount == 0); 1749 ASSERT(provider->ftp_mcount == 0); 1750 1751 /* 1752 * If this provider hasn't been retired, we need to explicitly drop the 1753 * count of active providers on the associated process structure. 1754 */ 1755 if (!provider->ftp_retired) { 1756 atomic_dec_64(&provider->ftp_proc->ftpc_acount); 1757 ASSERT(provider->ftp_proc->ftpc_acount < 1758 provider->ftp_proc->ftpc_rcount); 1759 } 1760 1761 fasttrap_proc_release(provider->ftp_proc); 1762 1763#ifndef illumos 1764 mutex_destroy(&provider->ftp_mtx); 1765 mutex_destroy(&provider->ftp_cmtx); 1766#endif 1767 kmem_free(provider, sizeof (fasttrap_provider_t)); 1768 1769 /* 1770 * Decrement p_dtrace_probes on the process whose provider we're 1771 * freeing. We don't have to worry about clobbering somone else's 1772 * modifications to it because we have locked the bucket that 1773 * corresponds to this process's hash chain in the provider hash 1774 * table. Don't sweat it if we can't find the process. 1775 */ 1776 if ((p = pfind(pid)) == NULL) { 1777 return; 1778 } 1779 1780 p->p_dtrace_probes--; 1781#ifndef illumos 1782 PROC_UNLOCK(p); 1783#endif 1784} 1785 1786static void 1787fasttrap_provider_retire(pid_t pid, const char *name, int mprov) 1788{ 1789 fasttrap_provider_t *fp; 1790 fasttrap_bucket_t *bucket; 1791 dtrace_provider_id_t provid; 1792 1793 ASSERT(strlen(name) < sizeof (fp->ftp_name)); 1794 1795 bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)]; 1796 mutex_enter(&bucket->ftb_mtx); 1797 1798 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) { 1799 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 && 1800 !fp->ftp_retired) 1801 break; 1802 } 1803 1804 if (fp == NULL) { 1805 mutex_exit(&bucket->ftb_mtx); 1806 return; 1807 } 1808 1809 mutex_enter(&fp->ftp_mtx); 1810 ASSERT(!mprov || fp->ftp_mcount > 0); 1811 if (mprov && --fp->ftp_mcount != 0) { 1812 mutex_exit(&fp->ftp_mtx); 1813 mutex_exit(&bucket->ftb_mtx); 1814 return; 1815 } 1816 1817 /* 1818 * Mark the provider to be removed in our post-processing step, mark it 1819 * retired, and drop the active count on its proc. Marking it indicates 1820 * that we should try to remove it; setting the retired flag indicates 1821 * that we're done with this provider; dropping the active the proc 1822 * releases our hold, and when this reaches zero (as it will during 1823 * exit or exec) the proc and associated providers become defunct. 1824 * 1825 * We obviously need to take the bucket lock before the provider lock 1826 * to perform the lookup, but we need to drop the provider lock 1827 * before calling into the DTrace framework since we acquire the 1828 * provider lock in callbacks invoked from the DTrace framework. The 1829 * bucket lock therefore protects the integrity of the provider hash 1830 * table. 1831 */ 1832 atomic_dec_64(&fp->ftp_proc->ftpc_acount); 1833 ASSERT(fp->ftp_proc->ftpc_acount < fp->ftp_proc->ftpc_rcount); 1834 1835 fp->ftp_retired = 1; 1836 fp->ftp_marked = 1; 1837 provid = fp->ftp_provid; 1838 mutex_exit(&fp->ftp_mtx); 1839 1840 /* 1841 * We don't have to worry about invalidating the same provider twice 1842 * since fasttrap_provider_lookup() will ignore provider that have 1843 * been marked as retired. 1844 */ 1845 dtrace_invalidate(provid); 1846 1847 mutex_exit(&bucket->ftb_mtx); 1848 1849 fasttrap_pid_cleanup(); 1850} 1851 1852static int 1853fasttrap_uint32_cmp(const void *ap, const void *bp) 1854{ 1855 return (*(const uint32_t *)ap - *(const uint32_t *)bp); 1856} 1857 1858static int 1859fasttrap_uint64_cmp(const void *ap, const void *bp) 1860{ 1861 return (*(const uint64_t *)ap - *(const uint64_t *)bp); 1862} 1863 1864static int 1865fasttrap_add_probe(fasttrap_probe_spec_t *pdata) 1866{ 1867 fasttrap_provider_t *provider; 1868 fasttrap_probe_t *pp; 1869 fasttrap_tracepoint_t *tp; 1870 char *name; 1871 int i, aframes = 0, whack; 1872 1873 /* 1874 * There needs to be at least one desired trace point. 1875 */ 1876 if (pdata->ftps_noffs == 0) 1877 return (EINVAL); 1878 1879 switch (pdata->ftps_type) { 1880 case DTFTP_ENTRY: 1881 name = "entry"; 1882 aframes = FASTTRAP_ENTRY_AFRAMES; 1883 break; 1884 case DTFTP_RETURN: 1885 name = "return"; 1886 aframes = FASTTRAP_RETURN_AFRAMES; 1887 break; 1888 case DTFTP_OFFSETS: 1889 name = NULL; 1890 break; 1891 default: 1892 return (EINVAL); 1893 } 1894 1895 if ((provider = fasttrap_provider_lookup(pdata->ftps_pid, 1896 FASTTRAP_PID_NAME, &pid_attr)) == NULL) 1897 return (ESRCH); 1898 1899 /* 1900 * Increment this reference count to indicate that a consumer is 1901 * actively adding a new probe associated with this provider. This 1902 * prevents the provider from being deleted -- we'll need to check 1903 * for pending deletions when we drop this reference count. 1904 */ 1905 provider->ftp_ccount++; 1906 mutex_exit(&provider->ftp_mtx); 1907 1908 /* 1909 * Grab the creation lock to ensure consistency between calls to 1910 * dtrace_probe_lookup() and dtrace_probe_create() in the face of 1911 * other threads creating probes. We must drop the provider lock 1912 * before taking this lock to avoid a three-way deadlock with the 1913 * DTrace framework. 1914 */ 1915 mutex_enter(&provider->ftp_cmtx); 1916 1917 if (name == NULL) { 1918 for (i = 0; i < pdata->ftps_noffs; i++) { 1919 char name_str[17]; 1920 1921 (void) sprintf(name_str, "%llx", 1922 (unsigned long long)pdata->ftps_offs[i]); 1923 1924 if (dtrace_probe_lookup(provider->ftp_provid, 1925 pdata->ftps_mod, pdata->ftps_func, name_str) != 0) 1926 continue; 1927 1928 atomic_inc_32(&fasttrap_total); 1929 1930 if (fasttrap_total > fasttrap_max) { 1931 atomic_dec_32(&fasttrap_total); 1932 goto no_mem; 1933 } 1934 1935 pp = kmem_zalloc(sizeof (fasttrap_probe_t), KM_SLEEP); 1936 1937 pp->ftp_prov = provider; 1938 pp->ftp_faddr = pdata->ftps_pc; 1939 pp->ftp_fsize = pdata->ftps_size; 1940 pp->ftp_pid = pdata->ftps_pid; 1941 pp->ftp_ntps = 1; 1942 1943 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), 1944 KM_SLEEP); 1945 1946 tp->ftt_proc = provider->ftp_proc; 1947 tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc; 1948 tp->ftt_pid = pdata->ftps_pid; 1949 1950 pp->ftp_tps[0].fit_tp = tp; 1951 pp->ftp_tps[0].fit_id.fti_probe = pp; 1952 pp->ftp_tps[0].fit_id.fti_ptype = pdata->ftps_type; 1953 1954 pp->ftp_id = dtrace_probe_create(provider->ftp_provid, 1955 pdata->ftps_mod, pdata->ftps_func, name_str, 1956 FASTTRAP_OFFSET_AFRAMES, pp); 1957 } 1958 1959 } else if (dtrace_probe_lookup(provider->ftp_provid, pdata->ftps_mod, 1960 pdata->ftps_func, name) == 0) { 1961 atomic_add_32(&fasttrap_total, pdata->ftps_noffs); 1962 1963 if (fasttrap_total > fasttrap_max) { 1964 atomic_add_32(&fasttrap_total, -pdata->ftps_noffs); 1965 goto no_mem; 1966 } 1967 1968 /* 1969 * Make sure all tracepoint program counter values are unique. 1970 * We later assume that each probe has exactly one tracepoint 1971 * for a given pc. 1972 */ 1973 qsort(pdata->ftps_offs, pdata->ftps_noffs, 1974 sizeof (uint64_t), fasttrap_uint64_cmp); 1975 for (i = 1; i < pdata->ftps_noffs; i++) { 1976 if (pdata->ftps_offs[i] > pdata->ftps_offs[i - 1]) 1977 continue; 1978 1979 atomic_add_32(&fasttrap_total, -pdata->ftps_noffs); 1980 goto no_mem; 1981 } 1982 1983 ASSERT(pdata->ftps_noffs > 0); 1984 pp = kmem_zalloc(offsetof(fasttrap_probe_t, 1985 ftp_tps[pdata->ftps_noffs]), KM_SLEEP); 1986 1987 pp->ftp_prov = provider; 1988 pp->ftp_faddr = pdata->ftps_pc; 1989 pp->ftp_fsize = pdata->ftps_size; 1990 pp->ftp_pid = pdata->ftps_pid; 1991 pp->ftp_ntps = pdata->ftps_noffs; 1992 1993 for (i = 0; i < pdata->ftps_noffs; i++) { 1994 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), 1995 KM_SLEEP); 1996 1997 tp->ftt_proc = provider->ftp_proc; 1998 tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc; 1999 tp->ftt_pid = pdata->ftps_pid; 2000 2001 pp->ftp_tps[i].fit_tp = tp; 2002 pp->ftp_tps[i].fit_id.fti_probe = pp; 2003 pp->ftp_tps[i].fit_id.fti_ptype = pdata->ftps_type; 2004 } 2005 2006 pp->ftp_id = dtrace_probe_create(provider->ftp_provid, 2007 pdata->ftps_mod, pdata->ftps_func, name, aframes, pp); 2008 } 2009 2010 mutex_exit(&provider->ftp_cmtx); 2011 2012 /* 2013 * We know that the provider is still valid since we incremented the 2014 * creation reference count. If someone tried to clean up this provider 2015 * while we were using it (e.g. because the process called exec(2) or 2016 * exit(2)), take note of that and try to clean it up now. 2017 */ 2018 mutex_enter(&provider->ftp_mtx); 2019 provider->ftp_ccount--; 2020 whack = provider->ftp_retired; 2021 mutex_exit(&provider->ftp_mtx); 2022 2023 if (whack) 2024 fasttrap_pid_cleanup(); 2025 2026 return (0); 2027 2028no_mem: 2029 /* 2030 * If we've exhausted the allowable resources, we'll try to remove 2031 * this provider to free some up. This is to cover the case where 2032 * the user has accidentally created many more probes than was 2033 * intended (e.g. pid123:::). 2034 */ 2035 mutex_exit(&provider->ftp_cmtx); 2036 mutex_enter(&provider->ftp_mtx); 2037 provider->ftp_ccount--; 2038 provider->ftp_marked = 1; 2039 mutex_exit(&provider->ftp_mtx); 2040 2041 fasttrap_pid_cleanup(); 2042 2043 return (ENOMEM); 2044} 2045 2046/*ARGSUSED*/ 2047static void * 2048fasttrap_meta_provide(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid) 2049{ 2050 fasttrap_provider_t *provider; 2051 2052 /* 2053 * A 32-bit unsigned integer (like a pid for example) can be 2054 * expressed in 10 or fewer decimal digits. Make sure that we'll 2055 * have enough space for the provider name. 2056 */ 2057 if (strlen(dhpv->dthpv_provname) + 10 >= 2058 sizeof (provider->ftp_name)) { 2059 printf("failed to instantiate provider %s: " 2060 "name too long to accomodate pid", dhpv->dthpv_provname); 2061 return (NULL); 2062 } 2063 2064 /* 2065 * Don't let folks spoof the true pid provider. 2066 */ 2067 if (strcmp(dhpv->dthpv_provname, FASTTRAP_PID_NAME) == 0) { 2068 printf("failed to instantiate provider %s: " 2069 "%s is an invalid name", dhpv->dthpv_provname, 2070 FASTTRAP_PID_NAME); 2071 return (NULL); 2072 } 2073 2074 /* 2075 * The highest stability class that fasttrap supports is ISA; cap 2076 * the stability of the new provider accordingly. 2077 */ 2078 if (dhpv->dthpv_pattr.dtpa_provider.dtat_class > DTRACE_CLASS_ISA) 2079 dhpv->dthpv_pattr.dtpa_provider.dtat_class = DTRACE_CLASS_ISA; 2080 if (dhpv->dthpv_pattr.dtpa_mod.dtat_class > DTRACE_CLASS_ISA) 2081 dhpv->dthpv_pattr.dtpa_mod.dtat_class = DTRACE_CLASS_ISA; 2082 if (dhpv->dthpv_pattr.dtpa_func.dtat_class > DTRACE_CLASS_ISA) 2083 dhpv->dthpv_pattr.dtpa_func.dtat_class = DTRACE_CLASS_ISA; 2084 if (dhpv->dthpv_pattr.dtpa_name.dtat_class > DTRACE_CLASS_ISA) 2085 dhpv->dthpv_pattr.dtpa_name.dtat_class = DTRACE_CLASS_ISA; 2086 if (dhpv->dthpv_pattr.dtpa_args.dtat_class > DTRACE_CLASS_ISA) 2087 dhpv->dthpv_pattr.dtpa_args.dtat_class = DTRACE_CLASS_ISA; 2088 2089 if ((provider = fasttrap_provider_lookup(pid, dhpv->dthpv_provname, 2090 &dhpv->dthpv_pattr)) == NULL) { 2091 printf("failed to instantiate provider %s for " 2092 "process %u", dhpv->dthpv_provname, (uint_t)pid); 2093 return (NULL); 2094 } 2095 2096 /* 2097 * Up the meta provider count so this provider isn't removed until 2098 * the meta provider has been told to remove it. 2099 */ 2100 provider->ftp_mcount++; 2101 2102 mutex_exit(&provider->ftp_mtx); 2103 2104 return (provider); 2105} 2106 2107/*ARGSUSED*/ 2108static void 2109fasttrap_meta_create_probe(void *arg, void *parg, 2110 dtrace_helper_probedesc_t *dhpb) 2111{ 2112 fasttrap_provider_t *provider = parg; 2113 fasttrap_probe_t *pp; 2114 fasttrap_tracepoint_t *tp; 2115 int i, j; 2116 uint32_t ntps; 2117 2118 /* 2119 * Since the meta provider count is non-zero we don't have to worry 2120 * about this provider disappearing. 2121 */ 2122 ASSERT(provider->ftp_mcount > 0); 2123 2124 /* 2125 * The offsets must be unique. 2126 */ 2127 qsort(dhpb->dthpb_offs, dhpb->dthpb_noffs, sizeof (uint32_t), 2128 fasttrap_uint32_cmp); 2129 for (i = 1; i < dhpb->dthpb_noffs; i++) { 2130 if (dhpb->dthpb_base + dhpb->dthpb_offs[i] <= 2131 dhpb->dthpb_base + dhpb->dthpb_offs[i - 1]) 2132 return; 2133 } 2134 2135 qsort(dhpb->dthpb_enoffs, dhpb->dthpb_nenoffs, sizeof (uint32_t), 2136 fasttrap_uint32_cmp); 2137 for (i = 1; i < dhpb->dthpb_nenoffs; i++) { 2138 if (dhpb->dthpb_base + dhpb->dthpb_enoffs[i] <= 2139 dhpb->dthpb_base + dhpb->dthpb_enoffs[i - 1]) 2140 return; 2141 } 2142 2143 /* 2144 * Grab the creation lock to ensure consistency between calls to 2145 * dtrace_probe_lookup() and dtrace_probe_create() in the face of 2146 * other threads creating probes. 2147 */ 2148 mutex_enter(&provider->ftp_cmtx); 2149 2150 if (dtrace_probe_lookup(provider->ftp_provid, dhpb->dthpb_mod, 2151 dhpb->dthpb_func, dhpb->dthpb_name) != 0) { 2152 mutex_exit(&provider->ftp_cmtx); 2153 return; 2154 } 2155 2156 ntps = dhpb->dthpb_noffs + dhpb->dthpb_nenoffs; 2157 ASSERT(ntps > 0); 2158 2159 atomic_add_32(&fasttrap_total, ntps); 2160 2161 if (fasttrap_total > fasttrap_max) { 2162 atomic_add_32(&fasttrap_total, -ntps); 2163 mutex_exit(&provider->ftp_cmtx); 2164 return; 2165 } 2166 2167 pp = kmem_zalloc(offsetof(fasttrap_probe_t, ftp_tps[ntps]), KM_SLEEP); 2168 2169 pp->ftp_prov = provider; 2170 pp->ftp_pid = provider->ftp_pid; 2171 pp->ftp_ntps = ntps; 2172 pp->ftp_nargs = dhpb->dthpb_xargc; 2173 pp->ftp_xtypes = dhpb->dthpb_xtypes; 2174 pp->ftp_ntypes = dhpb->dthpb_ntypes; 2175 2176 /* 2177 * First create a tracepoint for each actual point of interest. 2178 */ 2179 for (i = 0; i < dhpb->dthpb_noffs; i++) { 2180 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP); 2181 2182 tp->ftt_proc = provider->ftp_proc; 2183 tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_offs[i]; 2184 tp->ftt_pid = provider->ftp_pid; 2185 2186 pp->ftp_tps[i].fit_tp = tp; 2187 pp->ftp_tps[i].fit_id.fti_probe = pp; 2188#ifdef __sparc 2189 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_POST_OFFSETS; 2190#else 2191 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_OFFSETS; 2192#endif 2193 } 2194 2195 /* 2196 * Then create a tracepoint for each is-enabled point. 2197 */ 2198 for (j = 0; i < ntps; i++, j++) { 2199 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP); 2200 2201 tp->ftt_proc = provider->ftp_proc; 2202 tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_enoffs[j]; 2203 tp->ftt_pid = provider->ftp_pid; 2204 2205 pp->ftp_tps[i].fit_tp = tp; 2206 pp->ftp_tps[i].fit_id.fti_probe = pp; 2207 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_IS_ENABLED; 2208 } 2209 2210 /* 2211 * If the arguments are shuffled around we set the argument remapping 2212 * table. Later, when the probe fires, we only remap the arguments 2213 * if the table is non-NULL. 2214 */ 2215 for (i = 0; i < dhpb->dthpb_xargc; i++) { 2216 if (dhpb->dthpb_args[i] != i) { 2217 pp->ftp_argmap = dhpb->dthpb_args; 2218 break; 2219 } 2220 } 2221 2222 /* 2223 * The probe is fully constructed -- register it with DTrace. 2224 */ 2225 pp->ftp_id = dtrace_probe_create(provider->ftp_provid, dhpb->dthpb_mod, 2226 dhpb->dthpb_func, dhpb->dthpb_name, FASTTRAP_OFFSET_AFRAMES, pp); 2227 2228 mutex_exit(&provider->ftp_cmtx); 2229} 2230 2231/*ARGSUSED*/ 2232static void 2233fasttrap_meta_remove(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid) 2234{ 2235 /* 2236 * Clean up the USDT provider. There may be active consumers of the 2237 * provider busy adding probes, no damage will actually befall the 2238 * provider until that count has dropped to zero. This just puts 2239 * the provider on death row. 2240 */ 2241 fasttrap_provider_retire(pid, dhpv->dthpv_provname, 1); 2242} 2243 2244static dtrace_mops_t fasttrap_mops = { 2245 fasttrap_meta_create_probe, 2246 fasttrap_meta_provide, 2247 fasttrap_meta_remove 2248}; 2249 2250/*ARGSUSED*/ 2251static int 2252fasttrap_open(struct cdev *dev __unused, int oflags __unused, 2253 int devtype __unused, struct thread *td __unused) 2254{ 2255 return (0); 2256} 2257 2258/*ARGSUSED*/ 2259static int 2260fasttrap_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int fflag, 2261 struct thread *td) 2262{ 2263#ifdef notyet 2264 struct kinfo_proc kp; 2265 const cred_t *cr = td->td_ucred; 2266#endif 2267 if (!dtrace_attached()) 2268 return (EAGAIN); 2269 2270 if (cmd == FASTTRAPIOC_MAKEPROBE) { 2271 fasttrap_probe_spec_t *uprobe = *(fasttrap_probe_spec_t **)arg; 2272 fasttrap_probe_spec_t *probe; 2273 uint64_t noffs; 2274 size_t size; 2275 int ret, err; 2276 2277 if (copyin(&uprobe->ftps_noffs, &noffs, 2278 sizeof (uprobe->ftps_noffs))) 2279 return (EFAULT); 2280 2281 /* 2282 * Probes must have at least one tracepoint. 2283 */ 2284 if (noffs == 0) 2285 return (EINVAL); 2286 2287 size = sizeof (fasttrap_probe_spec_t) + 2288 sizeof (probe->ftps_offs[0]) * (noffs - 1); 2289 2290 if (size > 1024 * 1024) 2291 return (ENOMEM); 2292 2293 probe = kmem_alloc(size, KM_SLEEP); 2294 2295 if (copyin(uprobe, probe, size) != 0 || 2296 probe->ftps_noffs != noffs) { 2297 kmem_free(probe, size); 2298 return (EFAULT); 2299 } 2300 2301 /* 2302 * Verify that the function and module strings contain no 2303 * funny characters. 2304 */ 2305 if (u8_validate(probe->ftps_func, strlen(probe->ftps_func), 2306 NULL, U8_VALIDATE_ENTIRE, &err) < 0) { 2307 ret = EINVAL; 2308 goto err; 2309 } 2310 2311 if (u8_validate(probe->ftps_mod, strlen(probe->ftps_mod), 2312 NULL, U8_VALIDATE_ENTIRE, &err) < 0) { 2313 ret = EINVAL; 2314 goto err; 2315 } 2316 2317#ifdef notyet 2318 if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) { 2319 proc_t *p; 2320 pid_t pid = probe->ftps_pid; 2321 2322#ifdef illumos 2323 mutex_enter(&pidlock); 2324#endif 2325 /* 2326 * Report an error if the process doesn't exist 2327 * or is actively being birthed. 2328 */ 2329 sx_slock(&proctree_lock); 2330 p = pfind(pid); 2331 if (p) 2332 fill_kinfo_proc(p, &kp); 2333 sx_sunlock(&proctree_lock); 2334 if (p == NULL || kp.ki_stat == SIDL) { 2335#ifdef illumos 2336 mutex_exit(&pidlock); 2337#endif 2338 return (ESRCH); 2339 } 2340#ifdef illumos 2341 mutex_enter(&p->p_lock); 2342 mutex_exit(&pidlock); 2343#else 2344 PROC_LOCK_ASSERT(p, MA_OWNED); 2345#endif 2346 2347#ifdef notyet 2348 if ((ret = priv_proc_cred_perm(cr, p, NULL, 2349 VREAD | VWRITE)) != 0) { 2350#ifdef illumos 2351 mutex_exit(&p->p_lock); 2352#else 2353 PROC_UNLOCK(p); 2354#endif 2355 return (ret); 2356 } 2357#endif /* notyet */ 2358#ifdef illumos 2359 mutex_exit(&p->p_lock); 2360#else 2361 PROC_UNLOCK(p); 2362#endif 2363 } 2364#endif /* notyet */ 2365 2366 ret = fasttrap_add_probe(probe); 2367err: 2368 kmem_free(probe, size); 2369 2370 return (ret); 2371 2372 } else if (cmd == FASTTRAPIOC_GETINSTR) { 2373 fasttrap_instr_query_t instr; 2374 fasttrap_tracepoint_t *tp; 2375 uint_t index; 2376#ifdef illumos 2377 int ret; 2378#endif 2379 2380#ifdef illumos 2381 if (copyin((void *)arg, &instr, sizeof (instr)) != 0) 2382 return (EFAULT); 2383#endif 2384 2385#ifdef notyet 2386 if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) { 2387 proc_t *p; 2388 pid_t pid = instr.ftiq_pid; 2389 2390#ifdef illumos 2391 mutex_enter(&pidlock); 2392#endif 2393 /* 2394 * Report an error if the process doesn't exist 2395 * or is actively being birthed. 2396 */ 2397 sx_slock(&proctree_lock); 2398 p = pfind(pid); 2399 if (p) 2400 fill_kinfo_proc(p, &kp); 2401 sx_sunlock(&proctree_lock); 2402 if (p == NULL || kp.ki_stat == SIDL) { 2403#ifdef illumos 2404 mutex_exit(&pidlock); 2405#endif 2406 return (ESRCH); 2407 } 2408#ifdef illumos 2409 mutex_enter(&p->p_lock); 2410 mutex_exit(&pidlock); 2411#else 2412 PROC_LOCK_ASSERT(p, MA_OWNED); 2413#endif 2414 2415#ifdef notyet 2416 if ((ret = priv_proc_cred_perm(cr, p, NULL, 2417 VREAD)) != 0) { 2418#ifdef illumos 2419 mutex_exit(&p->p_lock); 2420#else 2421 PROC_UNLOCK(p); 2422#endif 2423 return (ret); 2424 } 2425#endif /* notyet */ 2426 2427#ifdef illumos 2428 mutex_exit(&p->p_lock); 2429#else 2430 PROC_UNLOCK(p); 2431#endif 2432 } 2433#endif /* notyet */ 2434 2435 index = FASTTRAP_TPOINTS_INDEX(instr.ftiq_pid, instr.ftiq_pc); 2436 2437 mutex_enter(&fasttrap_tpoints.fth_table[index].ftb_mtx); 2438 tp = fasttrap_tpoints.fth_table[index].ftb_data; 2439 while (tp != NULL) { 2440 if (instr.ftiq_pid == tp->ftt_pid && 2441 instr.ftiq_pc == tp->ftt_pc && 2442 tp->ftt_proc->ftpc_acount != 0) 2443 break; 2444 2445 tp = tp->ftt_next; 2446 } 2447 2448 if (tp == NULL) { 2449 mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx); 2450 return (ENOENT); 2451 } 2452 2453 bcopy(&tp->ftt_instr, &instr.ftiq_instr, 2454 sizeof (instr.ftiq_instr)); 2455 mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx); 2456 2457 if (copyout(&instr, (void *)arg, sizeof (instr)) != 0) 2458 return (EFAULT); 2459 2460 return (0); 2461 } 2462 2463 return (EINVAL); 2464} 2465 2466static int 2467fasttrap_load(void) 2468{ 2469 ulong_t nent; 2470 int i, ret; 2471 2472 /* Create the /dev/dtrace/fasttrap entry. */ 2473 fasttrap_cdev = make_dev(&fasttrap_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, 2474 "dtrace/fasttrap"); 2475 2476 mtx_init(&fasttrap_cleanup_mtx, "fasttrap clean", "dtrace", MTX_DEF); 2477 mutex_init(&fasttrap_count_mtx, "fasttrap count mtx", MUTEX_DEFAULT, 2478 NULL); 2479 2480#ifdef illumos 2481 fasttrap_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS, 2482 "fasttrap-max-probes", FASTTRAP_MAX_DEFAULT); 2483#else 2484 fasttrap_max = FASTTRAP_MAX_DEFAULT; 2485#endif 2486 fasttrap_total = 0; 2487 2488 /* 2489 * Conjure up the tracepoints hashtable... 2490 */ 2491#ifdef illumos 2492 nent = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS, 2493 "fasttrap-hash-size", FASTTRAP_TPOINTS_DEFAULT_SIZE); 2494#else 2495 nent = FASTTRAP_TPOINTS_DEFAULT_SIZE; 2496#endif 2497 2498 if (nent == 0 || nent > 0x1000000) 2499 nent = FASTTRAP_TPOINTS_DEFAULT_SIZE; 2500 2501 if (ISP2(nent)) 2502 fasttrap_tpoints.fth_nent = nent; 2503 else 2504 fasttrap_tpoints.fth_nent = 1 << fasttrap_highbit(nent); 2505 ASSERT(fasttrap_tpoints.fth_nent > 0); 2506 fasttrap_tpoints.fth_mask = fasttrap_tpoints.fth_nent - 1; 2507 fasttrap_tpoints.fth_table = kmem_zalloc(fasttrap_tpoints.fth_nent * 2508 sizeof (fasttrap_bucket_t), KM_SLEEP); 2509#ifndef illumos 2510 for (i = 0; i < fasttrap_tpoints.fth_nent; i++) 2511 mutex_init(&fasttrap_tpoints.fth_table[i].ftb_mtx, 2512 "tracepoints bucket mtx", MUTEX_DEFAULT, NULL); 2513#endif 2514 2515 /* 2516 * ... and the providers hash table... 2517 */ 2518 nent = FASTTRAP_PROVIDERS_DEFAULT_SIZE; 2519 if (ISP2(nent)) 2520 fasttrap_provs.fth_nent = nent; 2521 else 2522 fasttrap_provs.fth_nent = 1 << fasttrap_highbit(nent); 2523 ASSERT(fasttrap_provs.fth_nent > 0); 2524 fasttrap_provs.fth_mask = fasttrap_provs.fth_nent - 1; 2525 fasttrap_provs.fth_table = kmem_zalloc(fasttrap_provs.fth_nent * 2526 sizeof (fasttrap_bucket_t), KM_SLEEP); 2527#ifndef illumos 2528 for (i = 0; i < fasttrap_provs.fth_nent; i++) 2529 mutex_init(&fasttrap_provs.fth_table[i].ftb_mtx, 2530 "providers bucket mtx", MUTEX_DEFAULT, NULL); 2531#endif 2532 2533 ret = kproc_create(fasttrap_pid_cleanup_cb, NULL, 2534 &fasttrap_cleanup_proc, 0, 0, "ftcleanup"); 2535 if (ret != 0) { 2536 destroy_dev(fasttrap_cdev); 2537#ifndef illumos 2538 for (i = 0; i < fasttrap_provs.fth_nent; i++) 2539 mutex_destroy(&fasttrap_provs.fth_table[i].ftb_mtx); 2540 for (i = 0; i < fasttrap_tpoints.fth_nent; i++) 2541 mutex_destroy(&fasttrap_tpoints.fth_table[i].ftb_mtx); 2542#endif 2543 kmem_free(fasttrap_provs.fth_table, fasttrap_provs.fth_nent * 2544 sizeof (fasttrap_bucket_t)); 2545 mtx_destroy(&fasttrap_cleanup_mtx); 2546 mutex_destroy(&fasttrap_count_mtx); 2547 return (ret); 2548 } 2549 2550 2551 /* 2552 * ... and the procs hash table. 2553 */ 2554 nent = FASTTRAP_PROCS_DEFAULT_SIZE; 2555 if (ISP2(nent)) 2556 fasttrap_procs.fth_nent = nent; 2557 else 2558 fasttrap_procs.fth_nent = 1 << fasttrap_highbit(nent); 2559 ASSERT(fasttrap_procs.fth_nent > 0); 2560 fasttrap_procs.fth_mask = fasttrap_procs.fth_nent - 1; 2561 fasttrap_procs.fth_table = kmem_zalloc(fasttrap_procs.fth_nent * 2562 sizeof (fasttrap_bucket_t), KM_SLEEP); 2563#ifndef illumos 2564 for (i = 0; i < fasttrap_procs.fth_nent; i++) 2565 mutex_init(&fasttrap_procs.fth_table[i].ftb_mtx, 2566 "processes bucket mtx", MUTEX_DEFAULT, NULL); 2567 2568 CPU_FOREACH(i) { 2569 mutex_init(&fasttrap_cpuc_pid_lock[i], "fasttrap barrier", 2570 MUTEX_DEFAULT, NULL); 2571 } 2572 2573 /* 2574 * This event handler must run before kdtrace_thread_dtor() since it 2575 * accesses the thread's struct kdtrace_thread. 2576 */ 2577 fasttrap_thread_dtor_tag = EVENTHANDLER_REGISTER(thread_dtor, 2578 fasttrap_thread_dtor, NULL, EVENTHANDLER_PRI_FIRST); 2579#endif 2580 2581 /* 2582 * Install our hooks into fork(2), exec(2), and exit(2). 2583 */ 2584 dtrace_fasttrap_fork = &fasttrap_fork; 2585 dtrace_fasttrap_exit = &fasttrap_exec_exit; 2586 dtrace_fasttrap_exec = &fasttrap_exec_exit; 2587 2588 (void) dtrace_meta_register("fasttrap", &fasttrap_mops, NULL, 2589 &fasttrap_meta_id); 2590 2591 return (0); 2592} 2593 2594static int 2595fasttrap_unload(void) 2596{ 2597 int i, fail = 0; 2598 2599 /* 2600 * Unregister the meta-provider to make sure no new fasttrap- 2601 * managed providers come along while we're trying to close up 2602 * shop. If we fail to detach, we'll need to re-register as a 2603 * meta-provider. We can fail to unregister as a meta-provider 2604 * if providers we manage still exist. 2605 */ 2606 if (fasttrap_meta_id != DTRACE_METAPROVNONE && 2607 dtrace_meta_unregister(fasttrap_meta_id) != 0) 2608 return (-1); 2609 2610 /* 2611 * Iterate over all of our providers. If there's still a process 2612 * that corresponds to that pid, fail to detach. 2613 */ 2614 for (i = 0; i < fasttrap_provs.fth_nent; i++) { 2615 fasttrap_provider_t **fpp, *fp; 2616 fasttrap_bucket_t *bucket = &fasttrap_provs.fth_table[i]; 2617 2618 mutex_enter(&bucket->ftb_mtx); 2619 fpp = (fasttrap_provider_t **)&bucket->ftb_data; 2620 while ((fp = *fpp) != NULL) { 2621 /* 2622 * Acquire and release the lock as a simple way of 2623 * waiting for any other consumer to finish with 2624 * this provider. A thread must first acquire the 2625 * bucket lock so there's no chance of another thread 2626 * blocking on the provider's lock. 2627 */ 2628 mutex_enter(&fp->ftp_mtx); 2629 mutex_exit(&fp->ftp_mtx); 2630 2631 if (dtrace_unregister(fp->ftp_provid) != 0) { 2632 fail = 1; 2633 fpp = &fp->ftp_next; 2634 } else { 2635 *fpp = fp->ftp_next; 2636 fasttrap_provider_free(fp); 2637 } 2638 } 2639 2640 mutex_exit(&bucket->ftb_mtx); 2641 } 2642 2643 if (fail) { 2644 (void) dtrace_meta_register("fasttrap", &fasttrap_mops, NULL, 2645 &fasttrap_meta_id); 2646 2647 return (-1); 2648 } 2649 2650 /* 2651 * Stop new processes from entering these hooks now, before the 2652 * fasttrap_cleanup thread runs. That way all processes will hopefully 2653 * be out of these hooks before we free fasttrap_provs.fth_table 2654 */ 2655 ASSERT(dtrace_fasttrap_fork == &fasttrap_fork); 2656 dtrace_fasttrap_fork = NULL; 2657 2658 ASSERT(dtrace_fasttrap_exec == &fasttrap_exec_exit); 2659 dtrace_fasttrap_exec = NULL; 2660 2661 ASSERT(dtrace_fasttrap_exit == &fasttrap_exec_exit); 2662 dtrace_fasttrap_exit = NULL; 2663 2664 mtx_lock(&fasttrap_cleanup_mtx); 2665 fasttrap_cleanup_drain = 1; 2666 /* Wait for the cleanup thread to finish up and signal us. */ 2667 wakeup(&fasttrap_cleanup_cv); 2668 mtx_sleep(&fasttrap_cleanup_drain, &fasttrap_cleanup_mtx, 0, "ftcld", 2669 0); 2670 fasttrap_cleanup_proc = NULL; 2671 mtx_destroy(&fasttrap_cleanup_mtx); 2672 2673#ifdef DEBUG 2674 mutex_enter(&fasttrap_count_mtx); 2675 ASSERT(fasttrap_pid_count == 0); 2676 mutex_exit(&fasttrap_count_mtx); 2677#endif 2678 2679#ifndef illumos 2680 EVENTHANDLER_DEREGISTER(thread_dtor, fasttrap_thread_dtor_tag); 2681 2682 for (i = 0; i < fasttrap_tpoints.fth_nent; i++) 2683 mutex_destroy(&fasttrap_tpoints.fth_table[i].ftb_mtx); 2684 for (i = 0; i < fasttrap_provs.fth_nent; i++) 2685 mutex_destroy(&fasttrap_provs.fth_table[i].ftb_mtx); 2686 for (i = 0; i < fasttrap_procs.fth_nent; i++) 2687 mutex_destroy(&fasttrap_procs.fth_table[i].ftb_mtx); 2688#endif 2689 kmem_free(fasttrap_tpoints.fth_table, 2690 fasttrap_tpoints.fth_nent * sizeof (fasttrap_bucket_t)); 2691 fasttrap_tpoints.fth_nent = 0; 2692 2693 kmem_free(fasttrap_provs.fth_table, 2694 fasttrap_provs.fth_nent * sizeof (fasttrap_bucket_t)); 2695 fasttrap_provs.fth_nent = 0; 2696 2697 kmem_free(fasttrap_procs.fth_table, 2698 fasttrap_procs.fth_nent * sizeof (fasttrap_bucket_t)); 2699 fasttrap_procs.fth_nent = 0; 2700 2701#ifndef illumos 2702 destroy_dev(fasttrap_cdev); 2703 mutex_destroy(&fasttrap_count_mtx); 2704 CPU_FOREACH(i) { 2705 mutex_destroy(&fasttrap_cpuc_pid_lock[i]); 2706 } 2707#endif 2708 2709 return (0); 2710} 2711 2712/* ARGSUSED */ 2713static int 2714fasttrap_modevent(module_t mod __unused, int type, void *data __unused) 2715{ 2716 int error = 0; 2717 2718 switch (type) { 2719 case MOD_LOAD: 2720 break; 2721 2722 case MOD_UNLOAD: 2723 break; 2724 2725 case MOD_SHUTDOWN: 2726 break; 2727 2728 default: 2729 error = EOPNOTSUPP; 2730 break; 2731 } 2732 return (error); 2733} 2734 2735SYSINIT(fasttrap_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, fasttrap_load, 2736 NULL); 2737SYSUNINIT(fasttrap_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, 2738 fasttrap_unload, NULL); 2739 2740DEV_MODULE(fasttrap, fasttrap_modevent, NULL); 2741MODULE_VERSION(fasttrap, 1); 2742MODULE_DEPEND(fasttrap, dtrace, 1, 1, 1); 2743MODULE_DEPEND(fasttrap, opensolaris, 1, 1, 1); 2744