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