1 /* 2 * uprobes-based tracing events 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 16 * 17 * Copyright (C) IBM Corporation, 2010-2012 18 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> 19 */ 20 21 #include <linux/module.h> 22 #include <linux/uaccess.h> 23 #include <linux/uprobes.h> 24 #include <linux/namei.h> 25 #include <linux/string.h> 26 27 #include "trace_probe.h" 28 29 #define UPROBE_EVENT_SYSTEM "uprobes" 30 31 struct uprobe_trace_entry_head { 32 struct trace_entry ent; 33 unsigned long vaddr[]; 34 }; 35 36 #define SIZEOF_TRACE_ENTRY(is_return) \ 37 (sizeof(struct uprobe_trace_entry_head) + \ 38 sizeof(unsigned long) * (is_return ? 2 : 1)) 39 40 #define DATAOF_TRACE_ENTRY(entry, is_return) \ 41 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) 42 43 struct trace_uprobe_filter { 44 rwlock_t rwlock; 45 int nr_systemwide; 46 struct list_head perf_events; 47 }; 48 49 /* 50 * uprobe event core functions 51 */ 52 struct trace_uprobe { 53 struct list_head list; 54 struct ftrace_event_class class; 55 struct ftrace_event_call call; 56 struct trace_uprobe_filter filter; 57 struct uprobe_consumer consumer; 58 struct inode *inode; 59 char *filename; 60 unsigned long offset; 61 unsigned long nhit; 62 unsigned int flags; /* For TP_FLAG_* */ 63 ssize_t size; /* trace entry size */ 64 unsigned int nr_args; 65 struct probe_arg args[]; 66 }; 67 68 #define SIZEOF_TRACE_UPROBE(n) \ 69 (offsetof(struct trace_uprobe, args) + \ 70 (sizeof(struct probe_arg) * (n))) 71 72 static int register_uprobe_event(struct trace_uprobe *tu); 73 static int unregister_uprobe_event(struct trace_uprobe *tu); 74 75 static DEFINE_MUTEX(uprobe_lock); 76 static LIST_HEAD(uprobe_list); 77 78 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); 79 static int uretprobe_dispatcher(struct uprobe_consumer *con, 80 unsigned long func, struct pt_regs *regs); 81 82 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) 83 { 84 rwlock_init(&filter->rwlock); 85 filter->nr_systemwide = 0; 86 INIT_LIST_HEAD(&filter->perf_events); 87 } 88 89 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 90 { 91 return !filter->nr_systemwide && list_empty(&filter->perf_events); 92 } 93 94 static inline bool is_ret_probe(struct trace_uprobe *tu) 95 { 96 return tu->consumer.ret_handler != NULL; 97 } 98 99 /* 100 * Allocate new trace_uprobe and initialize it (including uprobes). 101 */ 102 static struct trace_uprobe * 103 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 104 { 105 struct trace_uprobe *tu; 106 107 if (!event || !is_good_name(event)) 108 return ERR_PTR(-EINVAL); 109 110 if (!group || !is_good_name(group)) 111 return ERR_PTR(-EINVAL); 112 113 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); 114 if (!tu) 115 return ERR_PTR(-ENOMEM); 116 117 tu->call.class = &tu->class; 118 tu->call.name = kstrdup(event, GFP_KERNEL); 119 if (!tu->call.name) 120 goto error; 121 122 tu->class.system = kstrdup(group, GFP_KERNEL); 123 if (!tu->class.system) 124 goto error; 125 126 INIT_LIST_HEAD(&tu->list); 127 tu->consumer.handler = uprobe_dispatcher; 128 if (is_ret) 129 tu->consumer.ret_handler = uretprobe_dispatcher; 130 init_trace_uprobe_filter(&tu->filter); 131 tu->call.flags |= TRACE_EVENT_FL_USE_CALL_FILTER; 132 return tu; 133 134 error: 135 kfree(tu->call.name); 136 kfree(tu); 137 138 return ERR_PTR(-ENOMEM); 139 } 140 141 static void free_trace_uprobe(struct trace_uprobe *tu) 142 { 143 int i; 144 145 for (i = 0; i < tu->nr_args; i++) 146 traceprobe_free_probe_arg(&tu->args[i]); 147 148 iput(tu->inode); 149 kfree(tu->call.class->system); 150 kfree(tu->call.name); 151 kfree(tu->filename); 152 kfree(tu); 153 } 154 155 static struct trace_uprobe *find_probe_event(const char *event, const char *group) 156 { 157 struct trace_uprobe *tu; 158 159 list_for_each_entry(tu, &uprobe_list, list) 160 if (strcmp(tu->call.name, event) == 0 && 161 strcmp(tu->call.class->system, group) == 0) 162 return tu; 163 164 return NULL; 165 } 166 167 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ 168 static int unregister_trace_uprobe(struct trace_uprobe *tu) 169 { 170 int ret; 171 172 ret = unregister_uprobe_event(tu); 173 if (ret) 174 return ret; 175 176 list_del(&tu->list); 177 free_trace_uprobe(tu); 178 return 0; 179 } 180 181 /* Register a trace_uprobe and probe_event */ 182 static int register_trace_uprobe(struct trace_uprobe *tu) 183 { 184 struct trace_uprobe *old_tp; 185 int ret; 186 187 mutex_lock(&uprobe_lock); 188 189 /* register as an event */ 190 old_tp = find_probe_event(tu->call.name, tu->call.class->system); 191 if (old_tp) { 192 /* delete old event */ 193 ret = unregister_trace_uprobe(old_tp); 194 if (ret) 195 goto end; 196 } 197 198 ret = register_uprobe_event(tu); 199 if (ret) { 200 pr_warning("Failed to register probe event(%d)\n", ret); 201 goto end; 202 } 203 204 list_add_tail(&tu->list, &uprobe_list); 205 206 end: 207 mutex_unlock(&uprobe_lock); 208 209 return ret; 210 } 211 212 /* 213 * Argument syntax: 214 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:SYMBOL [FETCHARGS] 215 * 216 * - Remove uprobe: -:[GRP/]EVENT 217 */ 218 static int create_trace_uprobe(int argc, char **argv) 219 { 220 struct trace_uprobe *tu; 221 struct inode *inode; 222 char *arg, *event, *group, *filename; 223 char buf[MAX_EVENT_NAME_LEN]; 224 struct path path; 225 unsigned long offset; 226 bool is_delete, is_return; 227 int i, ret; 228 229 inode = NULL; 230 ret = 0; 231 is_delete = false; 232 is_return = false; 233 event = NULL; 234 group = NULL; 235 236 /* argc must be >= 1 */ 237 if (argv[0][0] == '-') 238 is_delete = true; 239 else if (argv[0][0] == 'r') 240 is_return = true; 241 else if (argv[0][0] != 'p') { 242 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n"); 243 return -EINVAL; 244 } 245 246 if (argv[0][1] == ':') { 247 event = &argv[0][2]; 248 arg = strchr(event, '/'); 249 250 if (arg) { 251 group = event; 252 event = arg + 1; 253 event[-1] = '\0'; 254 255 if (strlen(group) == 0) { 256 pr_info("Group name is not specified\n"); 257 return -EINVAL; 258 } 259 } 260 if (strlen(event) == 0) { 261 pr_info("Event name is not specified\n"); 262 return -EINVAL; 263 } 264 } 265 if (!group) 266 group = UPROBE_EVENT_SYSTEM; 267 268 if (is_delete) { 269 int ret; 270 271 if (!event) { 272 pr_info("Delete command needs an event name.\n"); 273 return -EINVAL; 274 } 275 mutex_lock(&uprobe_lock); 276 tu = find_probe_event(event, group); 277 278 if (!tu) { 279 mutex_unlock(&uprobe_lock); 280 pr_info("Event %s/%s doesn't exist.\n", group, event); 281 return -ENOENT; 282 } 283 /* delete an event */ 284 ret = unregister_trace_uprobe(tu); 285 mutex_unlock(&uprobe_lock); 286 return ret; 287 } 288 289 if (argc < 2) { 290 pr_info("Probe point is not specified.\n"); 291 return -EINVAL; 292 } 293 if (isdigit(argv[1][0])) { 294 pr_info("probe point must be have a filename.\n"); 295 return -EINVAL; 296 } 297 arg = strchr(argv[1], ':'); 298 if (!arg) { 299 ret = -EINVAL; 300 goto fail_address_parse; 301 } 302 303 *arg++ = '\0'; 304 filename = argv[1]; 305 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 306 if (ret) 307 goto fail_address_parse; 308 309 inode = igrab(path.dentry->d_inode); 310 path_put(&path); 311 312 if (!inode || !S_ISREG(inode->i_mode)) { 313 ret = -EINVAL; 314 goto fail_address_parse; 315 } 316 317 ret = kstrtoul(arg, 0, &offset); 318 if (ret) 319 goto fail_address_parse; 320 321 argc -= 2; 322 argv += 2; 323 324 /* setup a probe */ 325 if (!event) { 326 char *tail; 327 char *ptr; 328 329 tail = kstrdup(kbasename(filename), GFP_KERNEL); 330 if (!tail) { 331 ret = -ENOMEM; 332 goto fail_address_parse; 333 } 334 335 ptr = strpbrk(tail, ".-_"); 336 if (ptr) 337 *ptr = '\0'; 338 339 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 340 event = buf; 341 kfree(tail); 342 } 343 344 tu = alloc_trace_uprobe(group, event, argc, is_return); 345 if (IS_ERR(tu)) { 346 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); 347 ret = PTR_ERR(tu); 348 goto fail_address_parse; 349 } 350 tu->offset = offset; 351 tu->inode = inode; 352 tu->filename = kstrdup(filename, GFP_KERNEL); 353 354 if (!tu->filename) { 355 pr_info("Failed to allocate filename.\n"); 356 ret = -ENOMEM; 357 goto error; 358 } 359 360 /* parse arguments */ 361 ret = 0; 362 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 363 /* Increment count for freeing args in error case */ 364 tu->nr_args++; 365 366 /* Parse argument name */ 367 arg = strchr(argv[i], '='); 368 if (arg) { 369 *arg++ = '\0'; 370 tu->args[i].name = kstrdup(argv[i], GFP_KERNEL); 371 } else { 372 arg = argv[i]; 373 /* If argument name is omitted, set "argN" */ 374 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); 375 tu->args[i].name = kstrdup(buf, GFP_KERNEL); 376 } 377 378 if (!tu->args[i].name) { 379 pr_info("Failed to allocate argument[%d] name.\n", i); 380 ret = -ENOMEM; 381 goto error; 382 } 383 384 if (!is_good_name(tu->args[i].name)) { 385 pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name); 386 ret = -EINVAL; 387 goto error; 388 } 389 390 if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) { 391 pr_info("Argument[%d] name '%s' conflicts with " 392 "another field.\n", i, argv[i]); 393 ret = -EINVAL; 394 goto error; 395 } 396 397 /* Parse fetch argument */ 398 ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false); 399 if (ret) { 400 pr_info("Parse error at argument[%d]. (%d)\n", i, ret); 401 goto error; 402 } 403 } 404 405 ret = register_trace_uprobe(tu); 406 if (ret) 407 goto error; 408 return 0; 409 410 error: 411 free_trace_uprobe(tu); 412 return ret; 413 414 fail_address_parse: 415 if (inode) 416 iput(inode); 417 418 pr_info("Failed to parse address or file.\n"); 419 420 return ret; 421 } 422 423 static int cleanup_all_probes(void) 424 { 425 struct trace_uprobe *tu; 426 int ret = 0; 427 428 mutex_lock(&uprobe_lock); 429 while (!list_empty(&uprobe_list)) { 430 tu = list_entry(uprobe_list.next, struct trace_uprobe, list); 431 ret = unregister_trace_uprobe(tu); 432 if (ret) 433 break; 434 } 435 mutex_unlock(&uprobe_lock); 436 return ret; 437 } 438 439 /* Probes listing interfaces */ 440 static void *probes_seq_start(struct seq_file *m, loff_t *pos) 441 { 442 mutex_lock(&uprobe_lock); 443 return seq_list_start(&uprobe_list, *pos); 444 } 445 446 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) 447 { 448 return seq_list_next(v, &uprobe_list, pos); 449 } 450 451 static void probes_seq_stop(struct seq_file *m, void *v) 452 { 453 mutex_unlock(&uprobe_lock); 454 } 455 456 static int probes_seq_show(struct seq_file *m, void *v) 457 { 458 struct trace_uprobe *tu = v; 459 char c = is_ret_probe(tu) ? 'r' : 'p'; 460 int i; 461 462 seq_printf(m, "%c:%s/%s", c, tu->call.class->system, tu->call.name); 463 seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset); 464 465 for (i = 0; i < tu->nr_args; i++) 466 seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm); 467 468 seq_printf(m, "\n"); 469 return 0; 470 } 471 472 static const struct seq_operations probes_seq_op = { 473 .start = probes_seq_start, 474 .next = probes_seq_next, 475 .stop = probes_seq_stop, 476 .show = probes_seq_show 477 }; 478 479 static int probes_open(struct inode *inode, struct file *file) 480 { 481 int ret; 482 483 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 484 ret = cleanup_all_probes(); 485 if (ret) 486 return ret; 487 } 488 489 return seq_open(file, &probes_seq_op); 490 } 491 492 static ssize_t probes_write(struct file *file, const char __user *buffer, 493 size_t count, loff_t *ppos) 494 { 495 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); 496 } 497 498 static const struct file_operations uprobe_events_ops = { 499 .owner = THIS_MODULE, 500 .open = probes_open, 501 .read = seq_read, 502 .llseek = seq_lseek, 503 .release = seq_release, 504 .write = probes_write, 505 }; 506 507 /* Probes profiling interfaces */ 508 static int probes_profile_seq_show(struct seq_file *m, void *v) 509 { 510 struct trace_uprobe *tu = v; 511 512 seq_printf(m, " %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit); 513 return 0; 514 } 515 516 static const struct seq_operations profile_seq_op = { 517 .start = probes_seq_start, 518 .next = probes_seq_next, 519 .stop = probes_seq_stop, 520 .show = probes_profile_seq_show 521 }; 522 523 static int profile_open(struct inode *inode, struct file *file) 524 { 525 return seq_open(file, &profile_seq_op); 526 } 527 528 static const struct file_operations uprobe_profile_ops = { 529 .owner = THIS_MODULE, 530 .open = profile_open, 531 .read = seq_read, 532 .llseek = seq_lseek, 533 .release = seq_release, 534 }; 535 536 static void uprobe_trace_print(struct trace_uprobe *tu, 537 unsigned long func, struct pt_regs *regs) 538 { 539 struct uprobe_trace_entry_head *entry; 540 struct ring_buffer_event *event; 541 struct ring_buffer *buffer; 542 void *data; 543 int size, i; 544 struct ftrace_event_call *call = &tu->call; 545 546 size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 547 event = trace_current_buffer_lock_reserve(&buffer, call->event.type, 548 size + tu->size, 0, 0); 549 if (!event) 550 return; 551 552 entry = ring_buffer_event_data(event); 553 if (is_ret_probe(tu)) { 554 entry->vaddr[0] = func; 555 entry->vaddr[1] = instruction_pointer(regs); 556 data = DATAOF_TRACE_ENTRY(entry, true); 557 } else { 558 entry->vaddr[0] = instruction_pointer(regs); 559 data = DATAOF_TRACE_ENTRY(entry, false); 560 } 561 562 for (i = 0; i < tu->nr_args; i++) 563 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); 564 565 if (!call_filter_check_discard(call, entry, buffer, event)) 566 trace_buffer_unlock_commit(buffer, event, 0, 0); 567 } 568 569 /* uprobe handler */ 570 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) 571 { 572 if (!is_ret_probe(tu)) 573 uprobe_trace_print(tu, 0, regs); 574 return 0; 575 } 576 577 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 578 struct pt_regs *regs) 579 { 580 uprobe_trace_print(tu, func, regs); 581 } 582 583 /* Event entry printers */ 584 static enum print_line_t 585 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 586 { 587 struct uprobe_trace_entry_head *entry; 588 struct trace_seq *s = &iter->seq; 589 struct trace_uprobe *tu; 590 u8 *data; 591 int i; 592 593 entry = (struct uprobe_trace_entry_head *)iter->ent; 594 tu = container_of(event, struct trace_uprobe, call.event); 595 596 if (is_ret_probe(tu)) { 597 if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", tu->call.name, 598 entry->vaddr[1], entry->vaddr[0])) 599 goto partial; 600 data = DATAOF_TRACE_ENTRY(entry, true); 601 } else { 602 if (!trace_seq_printf(s, "%s: (0x%lx)", tu->call.name, 603 entry->vaddr[0])) 604 goto partial; 605 data = DATAOF_TRACE_ENTRY(entry, false); 606 } 607 608 for (i = 0; i < tu->nr_args; i++) { 609 if (!tu->args[i].type->print(s, tu->args[i].name, 610 data + tu->args[i].offset, entry)) 611 goto partial; 612 } 613 614 if (trace_seq_puts(s, "\n")) 615 return TRACE_TYPE_HANDLED; 616 617 partial: 618 return TRACE_TYPE_PARTIAL_LINE; 619 } 620 621 static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu) 622 { 623 return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE); 624 } 625 626 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 627 enum uprobe_filter_ctx ctx, 628 struct mm_struct *mm); 629 630 static int 631 probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter) 632 { 633 int ret = 0; 634 635 if (is_trace_uprobe_enabled(tu)) 636 return -EINTR; 637 638 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 639 640 tu->flags |= flag; 641 tu->consumer.filter = filter; 642 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 643 if (ret) 644 tu->flags &= ~flag; 645 646 return ret; 647 } 648 649 static void probe_event_disable(struct trace_uprobe *tu, int flag) 650 { 651 if (!is_trace_uprobe_enabled(tu)) 652 return; 653 654 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 655 656 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 657 tu->flags &= ~flag; 658 } 659 660 static int uprobe_event_define_fields(struct ftrace_event_call *event_call) 661 { 662 int ret, i, size; 663 struct uprobe_trace_entry_head field; 664 struct trace_uprobe *tu = event_call->data; 665 666 if (is_ret_probe(tu)) { 667 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 668 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 669 size = SIZEOF_TRACE_ENTRY(true); 670 } else { 671 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 672 size = SIZEOF_TRACE_ENTRY(false); 673 } 674 /* Set argument names as fields */ 675 for (i = 0; i < tu->nr_args; i++) { 676 ret = trace_define_field(event_call, tu->args[i].type->fmttype, 677 tu->args[i].name, 678 size + tu->args[i].offset, 679 tu->args[i].type->size, 680 tu->args[i].type->is_signed, 681 FILTER_OTHER); 682 683 if (ret) 684 return ret; 685 } 686 return 0; 687 } 688 689 #define LEN_OR_ZERO (len ? len - pos : 0) 690 static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len) 691 { 692 const char *fmt, *arg; 693 int i; 694 int pos = 0; 695 696 if (is_ret_probe(tu)) { 697 fmt = "(%lx <- %lx)"; 698 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; 699 } else { 700 fmt = "(%lx)"; 701 arg = "REC->" FIELD_STRING_IP; 702 } 703 704 /* When len=0, we just calculate the needed length */ 705 706 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); 707 708 for (i = 0; i < tu->nr_args; i++) { 709 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s", 710 tu->args[i].name, tu->args[i].type->fmt); 711 } 712 713 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); 714 715 for (i = 0; i < tu->nr_args; i++) { 716 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", 717 tu->args[i].name); 718 } 719 720 return pos; /* return the length of print_fmt */ 721 } 722 #undef LEN_OR_ZERO 723 724 static int set_print_fmt(struct trace_uprobe *tu) 725 { 726 char *print_fmt; 727 int len; 728 729 /* First: called with 0 length to calculate the needed length */ 730 len = __set_print_fmt(tu, NULL, 0); 731 print_fmt = kmalloc(len + 1, GFP_KERNEL); 732 if (!print_fmt) 733 return -ENOMEM; 734 735 /* Second: actually write the @print_fmt */ 736 __set_print_fmt(tu, print_fmt, len + 1); 737 tu->call.print_fmt = print_fmt; 738 739 return 0; 740 } 741 742 #ifdef CONFIG_PERF_EVENTS 743 static bool 744 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 745 { 746 struct perf_event *event; 747 748 if (filter->nr_systemwide) 749 return true; 750 751 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 752 if (event->hw.tp_target->mm == mm) 753 return true; 754 } 755 756 return false; 757 } 758 759 static inline bool 760 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 761 { 762 return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm); 763 } 764 765 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 766 { 767 bool done; 768 769 write_lock(&tu->filter.rwlock); 770 if (event->hw.tp_target) { 771 /* 772 * event->parent != NULL means copy_process(), we can avoid 773 * uprobe_apply(). current->mm must be probed and we can rely 774 * on dup_mmap() which preserves the already installed bp's. 775 * 776 * attr.enable_on_exec means that exec/mmap will install the 777 * breakpoints we need. 778 */ 779 done = tu->filter.nr_systemwide || 780 event->parent || event->attr.enable_on_exec || 781 uprobe_filter_event(tu, event); 782 list_add(&event->hw.tp_list, &tu->filter.perf_events); 783 } else { 784 done = tu->filter.nr_systemwide; 785 tu->filter.nr_systemwide++; 786 } 787 write_unlock(&tu->filter.rwlock); 788 789 if (!done) 790 uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 791 792 return 0; 793 } 794 795 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 796 { 797 bool done; 798 799 write_lock(&tu->filter.rwlock); 800 if (event->hw.tp_target) { 801 list_del(&event->hw.tp_list); 802 done = tu->filter.nr_systemwide || 803 (event->hw.tp_target->flags & PF_EXITING) || 804 uprobe_filter_event(tu, event); 805 } else { 806 tu->filter.nr_systemwide--; 807 done = tu->filter.nr_systemwide; 808 } 809 write_unlock(&tu->filter.rwlock); 810 811 if (!done) 812 uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 813 814 return 0; 815 } 816 817 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 818 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 819 { 820 struct trace_uprobe *tu; 821 int ret; 822 823 tu = container_of(uc, struct trace_uprobe, consumer); 824 read_lock(&tu->filter.rwlock); 825 ret = __uprobe_perf_filter(&tu->filter, mm); 826 read_unlock(&tu->filter.rwlock); 827 828 return ret; 829 } 830 831 static void uprobe_perf_print(struct trace_uprobe *tu, 832 unsigned long func, struct pt_regs *regs) 833 { 834 struct ftrace_event_call *call = &tu->call; 835 struct uprobe_trace_entry_head *entry; 836 struct hlist_head *head; 837 void *data; 838 int size, rctx, i; 839 840 size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 841 size = ALIGN(size + tu->size + sizeof(u32), sizeof(u64)) - sizeof(u32); 842 843 preempt_disable(); 844 head = this_cpu_ptr(call->perf_events); 845 if (hlist_empty(head)) 846 goto out; 847 848 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); 849 if (!entry) 850 goto out; 851 852 if (is_ret_probe(tu)) { 853 entry->vaddr[0] = func; 854 entry->vaddr[1] = instruction_pointer(regs); 855 data = DATAOF_TRACE_ENTRY(entry, true); 856 } else { 857 entry->vaddr[0] = instruction_pointer(regs); 858 data = DATAOF_TRACE_ENTRY(entry, false); 859 } 860 861 for (i = 0; i < tu->nr_args; i++) 862 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); 863 864 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL); 865 out: 866 preempt_enable(); 867 } 868 869 /* uprobe profile handler */ 870 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) 871 { 872 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 873 return UPROBE_HANDLER_REMOVE; 874 875 if (!is_ret_probe(tu)) 876 uprobe_perf_print(tu, 0, regs); 877 return 0; 878 } 879 880 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 881 struct pt_regs *regs) 882 { 883 uprobe_perf_print(tu, func, regs); 884 } 885 #endif /* CONFIG_PERF_EVENTS */ 886 887 static 888 int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data) 889 { 890 struct trace_uprobe *tu = event->data; 891 892 switch (type) { 893 case TRACE_REG_REGISTER: 894 return probe_event_enable(tu, TP_FLAG_TRACE, NULL); 895 896 case TRACE_REG_UNREGISTER: 897 probe_event_disable(tu, TP_FLAG_TRACE); 898 return 0; 899 900 #ifdef CONFIG_PERF_EVENTS 901 case TRACE_REG_PERF_REGISTER: 902 return probe_event_enable(tu, TP_FLAG_PROFILE, uprobe_perf_filter); 903 904 case TRACE_REG_PERF_UNREGISTER: 905 probe_event_disable(tu, TP_FLAG_PROFILE); 906 return 0; 907 908 case TRACE_REG_PERF_OPEN: 909 return uprobe_perf_open(tu, data); 910 911 case TRACE_REG_PERF_CLOSE: 912 return uprobe_perf_close(tu, data); 913 914 #endif 915 default: 916 return 0; 917 } 918 return 0; 919 } 920 921 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 922 { 923 struct trace_uprobe *tu; 924 int ret = 0; 925 926 tu = container_of(con, struct trace_uprobe, consumer); 927 tu->nhit++; 928 929 if (tu->flags & TP_FLAG_TRACE) 930 ret |= uprobe_trace_func(tu, regs); 931 932 #ifdef CONFIG_PERF_EVENTS 933 if (tu->flags & TP_FLAG_PROFILE) 934 ret |= uprobe_perf_func(tu, regs); 935 #endif 936 return ret; 937 } 938 939 static int uretprobe_dispatcher(struct uprobe_consumer *con, 940 unsigned long func, struct pt_regs *regs) 941 { 942 struct trace_uprobe *tu; 943 944 tu = container_of(con, struct trace_uprobe, consumer); 945 946 if (tu->flags & TP_FLAG_TRACE) 947 uretprobe_trace_func(tu, func, regs); 948 949 #ifdef CONFIG_PERF_EVENTS 950 if (tu->flags & TP_FLAG_PROFILE) 951 uretprobe_perf_func(tu, func, regs); 952 #endif 953 return 0; 954 } 955 956 static struct trace_event_functions uprobe_funcs = { 957 .trace = print_uprobe_event 958 }; 959 960 static int register_uprobe_event(struct trace_uprobe *tu) 961 { 962 struct ftrace_event_call *call = &tu->call; 963 int ret; 964 965 /* Initialize ftrace_event_call */ 966 INIT_LIST_HEAD(&call->class->fields); 967 call->event.funcs = &uprobe_funcs; 968 call->class->define_fields = uprobe_event_define_fields; 969 970 if (set_print_fmt(tu) < 0) 971 return -ENOMEM; 972 973 ret = register_ftrace_event(&call->event); 974 if (!ret) { 975 kfree(call->print_fmt); 976 return -ENODEV; 977 } 978 call->flags = 0; 979 call->class->reg = trace_uprobe_register; 980 call->data = tu; 981 ret = trace_add_event_call(call); 982 983 if (ret) { 984 pr_info("Failed to register uprobe event: %s\n", call->name); 985 kfree(call->print_fmt); 986 unregister_ftrace_event(&call->event); 987 } 988 989 return ret; 990 } 991 992 static int unregister_uprobe_event(struct trace_uprobe *tu) 993 { 994 int ret; 995 996 /* tu->event is unregistered in trace_remove_event_call() */ 997 ret = trace_remove_event_call(&tu->call); 998 if (ret) 999 return ret; 1000 kfree(tu->call.print_fmt); 1001 tu->call.print_fmt = NULL; 1002 return 0; 1003 } 1004 1005 /* Make a trace interface for controling probe points */ 1006 static __init int init_uprobe_trace(void) 1007 { 1008 struct dentry *d_tracer; 1009 1010 d_tracer = tracing_init_dentry(); 1011 if (!d_tracer) 1012 return 0; 1013 1014 trace_create_file("uprobe_events", 0644, d_tracer, 1015 NULL, &uprobe_events_ops); 1016 /* Profile interface */ 1017 trace_create_file("uprobe_profile", 0444, d_tracer, 1018 NULL, &uprobe_profile_ops); 1019 return 0; 1020 } 1021 1022 fs_initcall(init_uprobe_trace); 1023