1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * uprobes-based tracing events 4 * 5 * Copyright (C) IBM Corporation, 2010-2012 6 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> 7 */ 8 #define pr_fmt(fmt) "trace_uprobe: " fmt 9 10 #include <linux/ctype.h> 11 #include <linux/module.h> 12 #include <linux/uaccess.h> 13 #include <linux/uprobes.h> 14 #include <linux/namei.h> 15 #include <linux/string.h> 16 #include <linux/rculist.h> 17 18 #include "trace_dynevent.h" 19 #include "trace_probe.h" 20 #include "trace_probe_tmpl.h" 21 22 #define UPROBE_EVENT_SYSTEM "uprobes" 23 24 struct uprobe_trace_entry_head { 25 struct trace_entry ent; 26 unsigned long vaddr[]; 27 }; 28 29 #define SIZEOF_TRACE_ENTRY(is_return) \ 30 (sizeof(struct uprobe_trace_entry_head) + \ 31 sizeof(unsigned long) * (is_return ? 2 : 1)) 32 33 #define DATAOF_TRACE_ENTRY(entry, is_return) \ 34 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) 35 36 struct trace_uprobe_filter { 37 rwlock_t rwlock; 38 int nr_systemwide; 39 struct list_head perf_events; 40 }; 41 42 static int trace_uprobe_create(int argc, const char **argv); 43 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev); 44 static int trace_uprobe_release(struct dyn_event *ev); 45 static bool trace_uprobe_is_busy(struct dyn_event *ev); 46 static bool trace_uprobe_match(const char *system, const char *event, 47 struct dyn_event *ev); 48 49 static struct dyn_event_operations trace_uprobe_ops = { 50 .create = trace_uprobe_create, 51 .show = trace_uprobe_show, 52 .is_busy = trace_uprobe_is_busy, 53 .free = trace_uprobe_release, 54 .match = trace_uprobe_match, 55 }; 56 57 /* 58 * uprobe event core functions 59 */ 60 struct trace_uprobe { 61 struct dyn_event devent; 62 struct trace_uprobe_filter filter; 63 struct uprobe_consumer consumer; 64 struct path path; 65 struct inode *inode; 66 char *filename; 67 unsigned long offset; 68 unsigned long ref_ctr_offset; 69 unsigned long nhit; 70 struct trace_probe tp; 71 }; 72 73 static bool is_trace_uprobe(struct dyn_event *ev) 74 { 75 return ev->ops == &trace_uprobe_ops; 76 } 77 78 static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev) 79 { 80 return container_of(ev, struct trace_uprobe, devent); 81 } 82 83 /** 84 * for_each_trace_uprobe - iterate over the trace_uprobe list 85 * @pos: the struct trace_uprobe * for each entry 86 * @dpos: the struct dyn_event * to use as a loop cursor 87 */ 88 #define for_each_trace_uprobe(pos, dpos) \ 89 for_each_dyn_event(dpos) \ 90 if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos))) 91 92 #define SIZEOF_TRACE_UPROBE(n) \ 93 (offsetof(struct trace_uprobe, tp.args) + \ 94 (sizeof(struct probe_arg) * (n))) 95 96 static int register_uprobe_event(struct trace_uprobe *tu); 97 static int unregister_uprobe_event(struct trace_uprobe *tu); 98 99 struct uprobe_dispatch_data { 100 struct trace_uprobe *tu; 101 unsigned long bp_addr; 102 }; 103 104 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); 105 static int uretprobe_dispatcher(struct uprobe_consumer *con, 106 unsigned long func, struct pt_regs *regs); 107 108 #ifdef CONFIG_STACK_GROWSUP 109 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 110 { 111 return addr - (n * sizeof(long)); 112 } 113 #else 114 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 115 { 116 return addr + (n * sizeof(long)); 117 } 118 #endif 119 120 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) 121 { 122 unsigned long ret; 123 unsigned long addr = user_stack_pointer(regs); 124 125 addr = adjust_stack_addr(addr, n); 126 127 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) 128 return 0; 129 130 return ret; 131 } 132 133 /* 134 * Uprobes-specific fetch functions 135 */ 136 static nokprobe_inline int 137 probe_mem_read(void *dest, void *src, size_t size) 138 { 139 void __user *vaddr = (void __force __user *)src; 140 141 return copy_from_user(dest, vaddr, size) ? -EFAULT : 0; 142 } 143 144 static nokprobe_inline int 145 probe_mem_read_user(void *dest, void *src, size_t size) 146 { 147 return probe_mem_read(dest, src, size); 148 } 149 150 /* 151 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max 152 * length and relative data location. 153 */ 154 static nokprobe_inline int 155 fetch_store_string(unsigned long addr, void *dest, void *base) 156 { 157 long ret; 158 u32 loc = *(u32 *)dest; 159 int maxlen = get_loc_len(loc); 160 u8 *dst = get_loc_data(dest, base); 161 void __user *src = (void __force __user *) addr; 162 163 if (unlikely(!maxlen)) 164 return -ENOMEM; 165 166 if (addr == FETCH_TOKEN_COMM) 167 ret = strlcpy(dst, current->comm, maxlen); 168 else 169 ret = strncpy_from_user(dst, src, maxlen); 170 if (ret >= 0) { 171 if (ret == maxlen) 172 dst[ret - 1] = '\0'; 173 else 174 /* 175 * Include the terminating null byte. In this case it 176 * was copied by strncpy_from_user but not accounted 177 * for in ret. 178 */ 179 ret++; 180 *(u32 *)dest = make_data_loc(ret, (void *)dst - base); 181 } 182 183 return ret; 184 } 185 186 static nokprobe_inline int 187 fetch_store_string_user(unsigned long addr, void *dest, void *base) 188 { 189 return fetch_store_string(addr, dest, base); 190 } 191 192 /* Return the length of string -- including null terminal byte */ 193 static nokprobe_inline int 194 fetch_store_strlen(unsigned long addr) 195 { 196 int len; 197 void __user *vaddr = (void __force __user *) addr; 198 199 if (addr == FETCH_TOKEN_COMM) 200 len = strlen(current->comm) + 1; 201 else 202 len = strnlen_user(vaddr, MAX_STRING_SIZE); 203 204 return (len > MAX_STRING_SIZE) ? 0 : len; 205 } 206 207 static nokprobe_inline int 208 fetch_store_strlen_user(unsigned long addr) 209 { 210 return fetch_store_strlen(addr); 211 } 212 213 static unsigned long translate_user_vaddr(unsigned long file_offset) 214 { 215 unsigned long base_addr; 216 struct uprobe_dispatch_data *udd; 217 218 udd = (void *) current->utask->vaddr; 219 220 base_addr = udd->bp_addr - udd->tu->offset; 221 return base_addr + file_offset; 222 } 223 224 /* Note that we don't verify it, since the code does not come from user space */ 225 static int 226 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 227 void *base) 228 { 229 unsigned long val; 230 231 /* 1st stage: get value from context */ 232 switch (code->op) { 233 case FETCH_OP_REG: 234 val = regs_get_register(regs, code->param); 235 break; 236 case FETCH_OP_STACK: 237 val = get_user_stack_nth(regs, code->param); 238 break; 239 case FETCH_OP_STACKP: 240 val = user_stack_pointer(regs); 241 break; 242 case FETCH_OP_RETVAL: 243 val = regs_return_value(regs); 244 break; 245 case FETCH_OP_IMM: 246 val = code->immediate; 247 break; 248 case FETCH_OP_COMM: 249 val = FETCH_TOKEN_COMM; 250 break; 251 case FETCH_OP_FOFFS: 252 val = translate_user_vaddr(code->immediate); 253 break; 254 default: 255 return -EILSEQ; 256 } 257 code++; 258 259 return process_fetch_insn_bottom(code, val, dest, base); 260 } 261 NOKPROBE_SYMBOL(process_fetch_insn) 262 263 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) 264 { 265 rwlock_init(&filter->rwlock); 266 filter->nr_systemwide = 0; 267 INIT_LIST_HEAD(&filter->perf_events); 268 } 269 270 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 271 { 272 return !filter->nr_systemwide && list_empty(&filter->perf_events); 273 } 274 275 static inline bool is_ret_probe(struct trace_uprobe *tu) 276 { 277 return tu->consumer.ret_handler != NULL; 278 } 279 280 static bool trace_uprobe_is_busy(struct dyn_event *ev) 281 { 282 struct trace_uprobe *tu = to_trace_uprobe(ev); 283 284 return trace_probe_is_enabled(&tu->tp); 285 } 286 287 static bool trace_uprobe_match(const char *system, const char *event, 288 struct dyn_event *ev) 289 { 290 struct trace_uprobe *tu = to_trace_uprobe(ev); 291 292 return strcmp(trace_probe_name(&tu->tp), event) == 0 && 293 (!system || strcmp(trace_probe_group_name(&tu->tp), system) == 0); 294 } 295 296 /* 297 * Allocate new trace_uprobe and initialize it (including uprobes). 298 */ 299 static struct trace_uprobe * 300 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 301 { 302 struct trace_uprobe *tu; 303 int ret; 304 305 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); 306 if (!tu) 307 return ERR_PTR(-ENOMEM); 308 309 ret = trace_probe_init(&tu->tp, event, group); 310 if (ret < 0) 311 goto error; 312 313 dyn_event_init(&tu->devent, &trace_uprobe_ops); 314 tu->consumer.handler = uprobe_dispatcher; 315 if (is_ret) 316 tu->consumer.ret_handler = uretprobe_dispatcher; 317 init_trace_uprobe_filter(&tu->filter); 318 return tu; 319 320 error: 321 kfree(tu); 322 323 return ERR_PTR(ret); 324 } 325 326 static void free_trace_uprobe(struct trace_uprobe *tu) 327 { 328 if (!tu) 329 return; 330 331 path_put(&tu->path); 332 trace_probe_cleanup(&tu->tp); 333 kfree(tu->filename); 334 kfree(tu); 335 } 336 337 static struct trace_uprobe *find_probe_event(const char *event, const char *group) 338 { 339 struct dyn_event *pos; 340 struct trace_uprobe *tu; 341 342 for_each_trace_uprobe(tu, pos) 343 if (strcmp(trace_probe_name(&tu->tp), event) == 0 && 344 strcmp(trace_probe_group_name(&tu->tp), group) == 0) 345 return tu; 346 347 return NULL; 348 } 349 350 /* Unregister a trace_uprobe and probe_event */ 351 static int unregister_trace_uprobe(struct trace_uprobe *tu) 352 { 353 int ret; 354 355 ret = unregister_uprobe_event(tu); 356 if (ret) 357 return ret; 358 359 dyn_event_remove(&tu->devent); 360 free_trace_uprobe(tu); 361 return 0; 362 } 363 364 /* 365 * Uprobe with multiple reference counter is not allowed. i.e. 366 * If inode and offset matches, reference counter offset *must* 367 * match as well. Though, there is one exception: If user is 368 * replacing old trace_uprobe with new one(same group/event), 369 * then we allow same uprobe with new reference counter as far 370 * as the new one does not conflict with any other existing 371 * ones. 372 */ 373 static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new) 374 { 375 struct dyn_event *pos; 376 struct trace_uprobe *tmp, *old = NULL; 377 struct inode *new_inode = d_real_inode(new->path.dentry); 378 379 old = find_probe_event(trace_probe_name(&new->tp), 380 trace_probe_group_name(&new->tp)); 381 382 for_each_trace_uprobe(tmp, pos) { 383 if ((old ? old != tmp : true) && 384 new_inode == d_real_inode(tmp->path.dentry) && 385 new->offset == tmp->offset && 386 new->ref_ctr_offset != tmp->ref_ctr_offset) { 387 pr_warn("Reference counter offset mismatch."); 388 return ERR_PTR(-EINVAL); 389 } 390 } 391 return old; 392 } 393 394 /* Register a trace_uprobe and probe_event */ 395 static int register_trace_uprobe(struct trace_uprobe *tu) 396 { 397 struct trace_uprobe *old_tu; 398 int ret; 399 400 mutex_lock(&event_mutex); 401 402 /* register as an event */ 403 old_tu = find_old_trace_uprobe(tu); 404 if (IS_ERR(old_tu)) { 405 ret = PTR_ERR(old_tu); 406 goto end; 407 } 408 409 if (old_tu) { 410 /* delete old event */ 411 ret = unregister_trace_uprobe(old_tu); 412 if (ret) 413 goto end; 414 } 415 416 ret = register_uprobe_event(tu); 417 if (ret) { 418 pr_warn("Failed to register probe event(%d)\n", ret); 419 goto end; 420 } 421 422 dyn_event_add(&tu->devent); 423 424 end: 425 mutex_unlock(&event_mutex); 426 427 return ret; 428 } 429 430 /* 431 * Argument syntax: 432 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] 433 */ 434 static int trace_uprobe_create(int argc, const char **argv) 435 { 436 struct trace_uprobe *tu; 437 const char *event = NULL, *group = UPROBE_EVENT_SYSTEM; 438 char *arg, *filename, *rctr, *rctr_end, *tmp; 439 char buf[MAX_EVENT_NAME_LEN]; 440 struct path path; 441 unsigned long offset, ref_ctr_offset; 442 bool is_return = false; 443 int i, ret; 444 445 ret = 0; 446 ref_ctr_offset = 0; 447 448 switch (argv[0][0]) { 449 case 'r': 450 is_return = true; 451 break; 452 case 'p': 453 break; 454 default: 455 return -ECANCELED; 456 } 457 458 if (argc < 2) 459 return -ECANCELED; 460 461 if (argv[0][1] == ':') 462 event = &argv[0][2]; 463 464 if (!strchr(argv[1], '/')) 465 return -ECANCELED; 466 467 filename = kstrdup(argv[1], GFP_KERNEL); 468 if (!filename) 469 return -ENOMEM; 470 471 /* Find the last occurrence, in case the path contains ':' too. */ 472 arg = strrchr(filename, ':'); 473 if (!arg || !isdigit(arg[1])) { 474 kfree(filename); 475 return -ECANCELED; 476 } 477 478 trace_probe_log_init("trace_uprobe", argc, argv); 479 trace_probe_log_set_index(1); /* filename is the 2nd argument */ 480 481 *arg++ = '\0'; 482 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 483 if (ret) { 484 trace_probe_log_err(0, FILE_NOT_FOUND); 485 kfree(filename); 486 trace_probe_log_clear(); 487 return ret; 488 } 489 if (!d_is_reg(path.dentry)) { 490 trace_probe_log_err(0, NO_REGULAR_FILE); 491 ret = -EINVAL; 492 goto fail_address_parse; 493 } 494 495 /* Parse reference counter offset if specified. */ 496 rctr = strchr(arg, '('); 497 if (rctr) { 498 rctr_end = strchr(rctr, ')'); 499 if (!rctr_end) { 500 ret = -EINVAL; 501 rctr_end = rctr + strlen(rctr); 502 trace_probe_log_err(rctr_end - filename, 503 REFCNT_OPEN_BRACE); 504 goto fail_address_parse; 505 } else if (rctr_end[1] != '\0') { 506 ret = -EINVAL; 507 trace_probe_log_err(rctr_end + 1 - filename, 508 BAD_REFCNT_SUFFIX); 509 goto fail_address_parse; 510 } 511 512 *rctr++ = '\0'; 513 *rctr_end = '\0'; 514 ret = kstrtoul(rctr, 0, &ref_ctr_offset); 515 if (ret) { 516 trace_probe_log_err(rctr - filename, BAD_REFCNT); 517 goto fail_address_parse; 518 } 519 } 520 521 /* Parse uprobe offset. */ 522 ret = kstrtoul(arg, 0, &offset); 523 if (ret) { 524 trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS); 525 goto fail_address_parse; 526 } 527 528 /* setup a probe */ 529 trace_probe_log_set_index(0); 530 if (event) { 531 ret = traceprobe_parse_event_name(&event, &group, buf, 532 event - argv[0]); 533 if (ret) 534 goto fail_address_parse; 535 } else { 536 char *tail; 537 char *ptr; 538 539 tail = kstrdup(kbasename(filename), GFP_KERNEL); 540 if (!tail) { 541 ret = -ENOMEM; 542 goto fail_address_parse; 543 } 544 545 ptr = strpbrk(tail, ".-_"); 546 if (ptr) 547 *ptr = '\0'; 548 549 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 550 event = buf; 551 kfree(tail); 552 } 553 554 argc -= 2; 555 argv += 2; 556 557 tu = alloc_trace_uprobe(group, event, argc, is_return); 558 if (IS_ERR(tu)) { 559 ret = PTR_ERR(tu); 560 /* This must return -ENOMEM otherwise there is a bug */ 561 WARN_ON_ONCE(ret != -ENOMEM); 562 goto fail_address_parse; 563 } 564 tu->offset = offset; 565 tu->ref_ctr_offset = ref_ctr_offset; 566 tu->path = path; 567 tu->filename = filename; 568 569 /* parse arguments */ 570 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 571 tmp = kstrdup(argv[i], GFP_KERNEL); 572 if (!tmp) { 573 ret = -ENOMEM; 574 goto error; 575 } 576 577 trace_probe_log_set_index(i + 2); 578 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp, 579 is_return ? TPARG_FL_RETURN : 0); 580 kfree(tmp); 581 if (ret) 582 goto error; 583 } 584 585 ret = traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)); 586 if (ret < 0) 587 goto error; 588 589 ret = register_trace_uprobe(tu); 590 if (!ret) 591 goto out; 592 593 error: 594 free_trace_uprobe(tu); 595 out: 596 trace_probe_log_clear(); 597 return ret; 598 599 fail_address_parse: 600 trace_probe_log_clear(); 601 path_put(&path); 602 kfree(filename); 603 604 return ret; 605 } 606 607 static int create_or_delete_trace_uprobe(int argc, char **argv) 608 { 609 int ret; 610 611 if (argv[0][0] == '-') 612 return dyn_event_release(argc, argv, &trace_uprobe_ops); 613 614 ret = trace_uprobe_create(argc, (const char **)argv); 615 return ret == -ECANCELED ? -EINVAL : ret; 616 } 617 618 static int trace_uprobe_release(struct dyn_event *ev) 619 { 620 struct trace_uprobe *tu = to_trace_uprobe(ev); 621 622 return unregister_trace_uprobe(tu); 623 } 624 625 /* Probes listing interfaces */ 626 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev) 627 { 628 struct trace_uprobe *tu = to_trace_uprobe(ev); 629 char c = is_ret_probe(tu) ? 'r' : 'p'; 630 int i; 631 632 seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, trace_probe_group_name(&tu->tp), 633 trace_probe_name(&tu->tp), tu->filename, 634 (int)(sizeof(void *) * 2), tu->offset); 635 636 if (tu->ref_ctr_offset) 637 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset); 638 639 for (i = 0; i < tu->tp.nr_args; i++) 640 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 641 642 seq_putc(m, '\n'); 643 return 0; 644 } 645 646 static int probes_seq_show(struct seq_file *m, void *v) 647 { 648 struct dyn_event *ev = v; 649 650 if (!is_trace_uprobe(ev)) 651 return 0; 652 653 return trace_uprobe_show(m, ev); 654 } 655 656 static const struct seq_operations probes_seq_op = { 657 .start = dyn_event_seq_start, 658 .next = dyn_event_seq_next, 659 .stop = dyn_event_seq_stop, 660 .show = probes_seq_show 661 }; 662 663 static int probes_open(struct inode *inode, struct file *file) 664 { 665 int ret; 666 667 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 668 ret = dyn_events_release_all(&trace_uprobe_ops); 669 if (ret) 670 return ret; 671 } 672 673 return seq_open(file, &probes_seq_op); 674 } 675 676 static ssize_t probes_write(struct file *file, const char __user *buffer, 677 size_t count, loff_t *ppos) 678 { 679 return trace_parse_run_command(file, buffer, count, ppos, 680 create_or_delete_trace_uprobe); 681 } 682 683 static const struct file_operations uprobe_events_ops = { 684 .owner = THIS_MODULE, 685 .open = probes_open, 686 .read = seq_read, 687 .llseek = seq_lseek, 688 .release = seq_release, 689 .write = probes_write, 690 }; 691 692 /* Probes profiling interfaces */ 693 static int probes_profile_seq_show(struct seq_file *m, void *v) 694 { 695 struct dyn_event *ev = v; 696 struct trace_uprobe *tu; 697 698 if (!is_trace_uprobe(ev)) 699 return 0; 700 701 tu = to_trace_uprobe(ev); 702 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 703 trace_probe_name(&tu->tp), tu->nhit); 704 return 0; 705 } 706 707 static const struct seq_operations profile_seq_op = { 708 .start = dyn_event_seq_start, 709 .next = dyn_event_seq_next, 710 .stop = dyn_event_seq_stop, 711 .show = probes_profile_seq_show 712 }; 713 714 static int profile_open(struct inode *inode, struct file *file) 715 { 716 return seq_open(file, &profile_seq_op); 717 } 718 719 static const struct file_operations uprobe_profile_ops = { 720 .owner = THIS_MODULE, 721 .open = profile_open, 722 .read = seq_read, 723 .llseek = seq_lseek, 724 .release = seq_release, 725 }; 726 727 struct uprobe_cpu_buffer { 728 struct mutex mutex; 729 void *buf; 730 }; 731 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 732 static int uprobe_buffer_refcnt; 733 734 static int uprobe_buffer_init(void) 735 { 736 int cpu, err_cpu; 737 738 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 739 if (uprobe_cpu_buffer == NULL) 740 return -ENOMEM; 741 742 for_each_possible_cpu(cpu) { 743 struct page *p = alloc_pages_node(cpu_to_node(cpu), 744 GFP_KERNEL, 0); 745 if (p == NULL) { 746 err_cpu = cpu; 747 goto err; 748 } 749 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 750 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 751 } 752 753 return 0; 754 755 err: 756 for_each_possible_cpu(cpu) { 757 if (cpu == err_cpu) 758 break; 759 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 760 } 761 762 free_percpu(uprobe_cpu_buffer); 763 return -ENOMEM; 764 } 765 766 static int uprobe_buffer_enable(void) 767 { 768 int ret = 0; 769 770 BUG_ON(!mutex_is_locked(&event_mutex)); 771 772 if (uprobe_buffer_refcnt++ == 0) { 773 ret = uprobe_buffer_init(); 774 if (ret < 0) 775 uprobe_buffer_refcnt--; 776 } 777 778 return ret; 779 } 780 781 static void uprobe_buffer_disable(void) 782 { 783 int cpu; 784 785 BUG_ON(!mutex_is_locked(&event_mutex)); 786 787 if (--uprobe_buffer_refcnt == 0) { 788 for_each_possible_cpu(cpu) 789 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 790 cpu)->buf); 791 792 free_percpu(uprobe_cpu_buffer); 793 uprobe_cpu_buffer = NULL; 794 } 795 } 796 797 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 798 { 799 struct uprobe_cpu_buffer *ucb; 800 int cpu; 801 802 cpu = raw_smp_processor_id(); 803 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 804 805 /* 806 * Use per-cpu buffers for fastest access, but we might migrate 807 * so the mutex makes sure we have sole access to it. 808 */ 809 mutex_lock(&ucb->mutex); 810 811 return ucb; 812 } 813 814 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 815 { 816 mutex_unlock(&ucb->mutex); 817 } 818 819 static void __uprobe_trace_func(struct trace_uprobe *tu, 820 unsigned long func, struct pt_regs *regs, 821 struct uprobe_cpu_buffer *ucb, int dsize, 822 struct trace_event_file *trace_file) 823 { 824 struct uprobe_trace_entry_head *entry; 825 struct ring_buffer_event *event; 826 struct ring_buffer *buffer; 827 void *data; 828 int size, esize; 829 struct trace_event_call *call = trace_probe_event_call(&tu->tp); 830 831 WARN_ON(call != trace_file->event_call); 832 833 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 834 return; 835 836 if (trace_trigger_soft_disabled(trace_file)) 837 return; 838 839 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 840 size = esize + tu->tp.size + dsize; 841 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 842 call->event.type, size, 0, 0); 843 if (!event) 844 return; 845 846 entry = ring_buffer_event_data(event); 847 if (is_ret_probe(tu)) { 848 entry->vaddr[0] = func; 849 entry->vaddr[1] = instruction_pointer(regs); 850 data = DATAOF_TRACE_ENTRY(entry, true); 851 } else { 852 entry->vaddr[0] = instruction_pointer(regs); 853 data = DATAOF_TRACE_ENTRY(entry, false); 854 } 855 856 memcpy(data, ucb->buf, tu->tp.size + dsize); 857 858 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); 859 } 860 861 /* uprobe handler */ 862 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 863 struct uprobe_cpu_buffer *ucb, int dsize) 864 { 865 struct event_file_link *link; 866 867 if (is_ret_probe(tu)) 868 return 0; 869 870 rcu_read_lock(); 871 trace_probe_for_each_link_rcu(link, &tu->tp) 872 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 873 rcu_read_unlock(); 874 875 return 0; 876 } 877 878 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 879 struct pt_regs *regs, 880 struct uprobe_cpu_buffer *ucb, int dsize) 881 { 882 struct event_file_link *link; 883 884 rcu_read_lock(); 885 trace_probe_for_each_link_rcu(link, &tu->tp) 886 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 887 rcu_read_unlock(); 888 } 889 890 /* Event entry printers */ 891 static enum print_line_t 892 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 893 { 894 struct uprobe_trace_entry_head *entry; 895 struct trace_seq *s = &iter->seq; 896 struct trace_uprobe *tu; 897 u8 *data; 898 899 entry = (struct uprobe_trace_entry_head *)iter->ent; 900 tu = container_of(event, struct trace_uprobe, tp.call.event); 901 902 if (is_ret_probe(tu)) { 903 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 904 trace_probe_name(&tu->tp), 905 entry->vaddr[1], entry->vaddr[0]); 906 data = DATAOF_TRACE_ENTRY(entry, true); 907 } else { 908 trace_seq_printf(s, "%s: (0x%lx)", 909 trace_probe_name(&tu->tp), 910 entry->vaddr[0]); 911 data = DATAOF_TRACE_ENTRY(entry, false); 912 } 913 914 if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0) 915 goto out; 916 917 trace_seq_putc(s, '\n'); 918 919 out: 920 return trace_handle_return(s); 921 } 922 923 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 924 enum uprobe_filter_ctx ctx, 925 struct mm_struct *mm); 926 927 static int 928 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, 929 filter_func_t filter) 930 { 931 bool enabled = trace_probe_is_enabled(&tu->tp); 932 int ret; 933 934 if (file) { 935 if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE)) 936 return -EINTR; 937 938 ret = trace_probe_add_file(&tu->tp, file); 939 if (ret < 0) 940 return ret; 941 } else { 942 if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE)) 943 return -EINTR; 944 945 trace_probe_set_flag(&tu->tp, TP_FLAG_PROFILE); 946 } 947 948 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 949 950 if (enabled) 951 return 0; 952 953 ret = uprobe_buffer_enable(); 954 if (ret) 955 goto err_flags; 956 957 tu->consumer.filter = filter; 958 tu->inode = d_real_inode(tu->path.dentry); 959 if (tu->ref_ctr_offset) { 960 ret = uprobe_register_refctr(tu->inode, tu->offset, 961 tu->ref_ctr_offset, &tu->consumer); 962 } else { 963 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 964 } 965 966 if (ret) 967 goto err_buffer; 968 969 return 0; 970 971 err_buffer: 972 uprobe_buffer_disable(); 973 974 err_flags: 975 if (file) 976 trace_probe_remove_file(&tu->tp, file); 977 else 978 trace_probe_clear_flag(&tu->tp, TP_FLAG_PROFILE); 979 980 return ret; 981 } 982 983 static void 984 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) 985 { 986 if (!trace_probe_is_enabled(&tu->tp)) 987 return; 988 989 if (file) { 990 if (trace_probe_remove_file(&tu->tp, file) < 0) 991 return; 992 993 if (trace_probe_is_enabled(&tu->tp)) 994 return; 995 } else 996 trace_probe_clear_flag(&tu->tp, TP_FLAG_PROFILE); 997 998 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 999 1000 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 1001 tu->inode = NULL; 1002 1003 uprobe_buffer_disable(); 1004 } 1005 1006 static int uprobe_event_define_fields(struct trace_event_call *event_call) 1007 { 1008 int ret, size; 1009 struct uprobe_trace_entry_head field; 1010 struct trace_uprobe *tu = event_call->data; 1011 1012 if (is_ret_probe(tu)) { 1013 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 1014 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 1015 size = SIZEOF_TRACE_ENTRY(true); 1016 } else { 1017 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 1018 size = SIZEOF_TRACE_ENTRY(false); 1019 } 1020 1021 return traceprobe_define_arg_fields(event_call, size, &tu->tp); 1022 } 1023 1024 #ifdef CONFIG_PERF_EVENTS 1025 static bool 1026 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1027 { 1028 struct perf_event *event; 1029 1030 if (filter->nr_systemwide) 1031 return true; 1032 1033 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1034 if (event->hw.target->mm == mm) 1035 return true; 1036 } 1037 1038 return false; 1039 } 1040 1041 static inline bool 1042 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1043 { 1044 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1045 } 1046 1047 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1048 { 1049 bool done; 1050 1051 write_lock(&tu->filter.rwlock); 1052 if (event->hw.target) { 1053 list_del(&event->hw.tp_list); 1054 done = tu->filter.nr_systemwide || 1055 (event->hw.target->flags & PF_EXITING) || 1056 uprobe_filter_event(tu, event); 1057 } else { 1058 tu->filter.nr_systemwide--; 1059 done = tu->filter.nr_systemwide; 1060 } 1061 write_unlock(&tu->filter.rwlock); 1062 1063 if (!done) 1064 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1065 1066 return 0; 1067 } 1068 1069 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1070 { 1071 bool done; 1072 int err; 1073 1074 write_lock(&tu->filter.rwlock); 1075 if (event->hw.target) { 1076 /* 1077 * event->parent != NULL means copy_process(), we can avoid 1078 * uprobe_apply(). current->mm must be probed and we can rely 1079 * on dup_mmap() which preserves the already installed bp's. 1080 * 1081 * attr.enable_on_exec means that exec/mmap will install the 1082 * breakpoints we need. 1083 */ 1084 done = tu->filter.nr_systemwide || 1085 event->parent || event->attr.enable_on_exec || 1086 uprobe_filter_event(tu, event); 1087 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1088 } else { 1089 done = tu->filter.nr_systemwide; 1090 tu->filter.nr_systemwide++; 1091 } 1092 write_unlock(&tu->filter.rwlock); 1093 1094 err = 0; 1095 if (!done) { 1096 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1097 if (err) 1098 uprobe_perf_close(tu, event); 1099 } 1100 return err; 1101 } 1102 1103 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1104 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1105 { 1106 struct trace_uprobe *tu; 1107 int ret; 1108 1109 tu = container_of(uc, struct trace_uprobe, consumer); 1110 read_lock(&tu->filter.rwlock); 1111 ret = __uprobe_perf_filter(&tu->filter, mm); 1112 read_unlock(&tu->filter.rwlock); 1113 1114 return ret; 1115 } 1116 1117 static void __uprobe_perf_func(struct trace_uprobe *tu, 1118 unsigned long func, struct pt_regs *regs, 1119 struct uprobe_cpu_buffer *ucb, int dsize) 1120 { 1121 struct trace_event_call *call = trace_probe_event_call(&tu->tp); 1122 struct uprobe_trace_entry_head *entry; 1123 struct hlist_head *head; 1124 void *data; 1125 int size, esize; 1126 int rctx; 1127 1128 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1129 return; 1130 1131 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1132 1133 size = esize + tu->tp.size + dsize; 1134 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1135 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1136 return; 1137 1138 preempt_disable(); 1139 head = this_cpu_ptr(call->perf_events); 1140 if (hlist_empty(head)) 1141 goto out; 1142 1143 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1144 if (!entry) 1145 goto out; 1146 1147 if (is_ret_probe(tu)) { 1148 entry->vaddr[0] = func; 1149 entry->vaddr[1] = instruction_pointer(regs); 1150 data = DATAOF_TRACE_ENTRY(entry, true); 1151 } else { 1152 entry->vaddr[0] = instruction_pointer(regs); 1153 data = DATAOF_TRACE_ENTRY(entry, false); 1154 } 1155 1156 memcpy(data, ucb->buf, tu->tp.size + dsize); 1157 1158 if (size - esize > tu->tp.size + dsize) { 1159 int len = tu->tp.size + dsize; 1160 1161 memset(data + len, 0, size - esize - len); 1162 } 1163 1164 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1165 head, NULL); 1166 out: 1167 preempt_enable(); 1168 } 1169 1170 /* uprobe profile handler */ 1171 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1172 struct uprobe_cpu_buffer *ucb, int dsize) 1173 { 1174 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1175 return UPROBE_HANDLER_REMOVE; 1176 1177 if (!is_ret_probe(tu)) 1178 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1179 return 0; 1180 } 1181 1182 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1183 struct pt_regs *regs, 1184 struct uprobe_cpu_buffer *ucb, int dsize) 1185 { 1186 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1187 } 1188 1189 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type, 1190 const char **filename, u64 *probe_offset, 1191 bool perf_type_tracepoint) 1192 { 1193 const char *pevent = trace_event_name(event->tp_event); 1194 const char *group = event->tp_event->class->system; 1195 struct trace_uprobe *tu; 1196 1197 if (perf_type_tracepoint) 1198 tu = find_probe_event(pevent, group); 1199 else 1200 tu = event->tp_event->data; 1201 if (!tu) 1202 return -EINVAL; 1203 1204 *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE 1205 : BPF_FD_TYPE_UPROBE; 1206 *filename = tu->filename; 1207 *probe_offset = tu->offset; 1208 return 0; 1209 } 1210 #endif /* CONFIG_PERF_EVENTS */ 1211 1212 static int 1213 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, 1214 void *data) 1215 { 1216 struct trace_uprobe *tu = event->data; 1217 struct trace_event_file *file = data; 1218 1219 switch (type) { 1220 case TRACE_REG_REGISTER: 1221 return probe_event_enable(tu, file, NULL); 1222 1223 case TRACE_REG_UNREGISTER: 1224 probe_event_disable(tu, file); 1225 return 0; 1226 1227 #ifdef CONFIG_PERF_EVENTS 1228 case TRACE_REG_PERF_REGISTER: 1229 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1230 1231 case TRACE_REG_PERF_UNREGISTER: 1232 probe_event_disable(tu, NULL); 1233 return 0; 1234 1235 case TRACE_REG_PERF_OPEN: 1236 return uprobe_perf_open(tu, data); 1237 1238 case TRACE_REG_PERF_CLOSE: 1239 return uprobe_perf_close(tu, data); 1240 1241 #endif 1242 default: 1243 return 0; 1244 } 1245 return 0; 1246 } 1247 1248 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1249 { 1250 struct trace_uprobe *tu; 1251 struct uprobe_dispatch_data udd; 1252 struct uprobe_cpu_buffer *ucb; 1253 int dsize, esize; 1254 int ret = 0; 1255 1256 1257 tu = container_of(con, struct trace_uprobe, consumer); 1258 tu->nhit++; 1259 1260 udd.tu = tu; 1261 udd.bp_addr = instruction_pointer(regs); 1262 1263 current->utask->vaddr = (unsigned long) &udd; 1264 1265 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1266 return 0; 1267 1268 dsize = __get_data_size(&tu->tp, regs); 1269 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1270 1271 ucb = uprobe_buffer_get(); 1272 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1273 1274 if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE)) 1275 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1276 1277 #ifdef CONFIG_PERF_EVENTS 1278 if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE)) 1279 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1280 #endif 1281 uprobe_buffer_put(ucb); 1282 return ret; 1283 } 1284 1285 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1286 unsigned long func, struct pt_regs *regs) 1287 { 1288 struct trace_uprobe *tu; 1289 struct uprobe_dispatch_data udd; 1290 struct uprobe_cpu_buffer *ucb; 1291 int dsize, esize; 1292 1293 tu = container_of(con, struct trace_uprobe, consumer); 1294 1295 udd.tu = tu; 1296 udd.bp_addr = func; 1297 1298 current->utask->vaddr = (unsigned long) &udd; 1299 1300 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1301 return 0; 1302 1303 dsize = __get_data_size(&tu->tp, regs); 1304 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1305 1306 ucb = uprobe_buffer_get(); 1307 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1308 1309 if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE)) 1310 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1311 1312 #ifdef CONFIG_PERF_EVENTS 1313 if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE)) 1314 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1315 #endif 1316 uprobe_buffer_put(ucb); 1317 return 0; 1318 } 1319 1320 static struct trace_event_functions uprobe_funcs = { 1321 .trace = print_uprobe_event 1322 }; 1323 1324 static inline void init_trace_event_call(struct trace_uprobe *tu) 1325 { 1326 struct trace_event_call *call = trace_probe_event_call(&tu->tp); 1327 1328 call->event.funcs = &uprobe_funcs; 1329 call->class->define_fields = uprobe_event_define_fields; 1330 1331 call->flags = TRACE_EVENT_FL_UPROBE | TRACE_EVENT_FL_CAP_ANY; 1332 call->class->reg = trace_uprobe_register; 1333 call->data = tu; 1334 } 1335 1336 static int register_uprobe_event(struct trace_uprobe *tu) 1337 { 1338 init_trace_event_call(tu); 1339 1340 return trace_probe_register_event_call(&tu->tp); 1341 } 1342 1343 static int unregister_uprobe_event(struct trace_uprobe *tu) 1344 { 1345 return trace_probe_unregister_event_call(&tu->tp); 1346 } 1347 1348 #ifdef CONFIG_PERF_EVENTS 1349 struct trace_event_call * 1350 create_local_trace_uprobe(char *name, unsigned long offs, 1351 unsigned long ref_ctr_offset, bool is_return) 1352 { 1353 struct trace_uprobe *tu; 1354 struct path path; 1355 int ret; 1356 1357 ret = kern_path(name, LOOKUP_FOLLOW, &path); 1358 if (ret) 1359 return ERR_PTR(ret); 1360 1361 if (!d_is_reg(path.dentry)) { 1362 path_put(&path); 1363 return ERR_PTR(-EINVAL); 1364 } 1365 1366 /* 1367 * local trace_kprobes are not added to dyn_event, so they are never 1368 * searched in find_trace_kprobe(). Therefore, there is no concern of 1369 * duplicated name "DUMMY_EVENT" here. 1370 */ 1371 tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0, 1372 is_return); 1373 1374 if (IS_ERR(tu)) { 1375 pr_info("Failed to allocate trace_uprobe.(%d)\n", 1376 (int)PTR_ERR(tu)); 1377 path_put(&path); 1378 return ERR_CAST(tu); 1379 } 1380 1381 tu->offset = offs; 1382 tu->path = path; 1383 tu->ref_ctr_offset = ref_ctr_offset; 1384 tu->filename = kstrdup(name, GFP_KERNEL); 1385 init_trace_event_call(tu); 1386 1387 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) { 1388 ret = -ENOMEM; 1389 goto error; 1390 } 1391 1392 return trace_probe_event_call(&tu->tp); 1393 error: 1394 free_trace_uprobe(tu); 1395 return ERR_PTR(ret); 1396 } 1397 1398 void destroy_local_trace_uprobe(struct trace_event_call *event_call) 1399 { 1400 struct trace_uprobe *tu; 1401 1402 tu = container_of(event_call, struct trace_uprobe, tp.call); 1403 1404 free_trace_uprobe(tu); 1405 } 1406 #endif /* CONFIG_PERF_EVENTS */ 1407 1408 /* Make a trace interface for controling probe points */ 1409 static __init int init_uprobe_trace(void) 1410 { 1411 struct dentry *d_tracer; 1412 int ret; 1413 1414 ret = dyn_event_register(&trace_uprobe_ops); 1415 if (ret) 1416 return ret; 1417 1418 d_tracer = tracing_init_dentry(); 1419 if (IS_ERR(d_tracer)) 1420 return 0; 1421 1422 trace_create_file("uprobe_events", 0644, d_tracer, 1423 NULL, &uprobe_events_ops); 1424 /* Profile interface */ 1425 trace_create_file("uprobe_profile", 0444, d_tracer, 1426 NULL, &uprobe_profile_ops); 1427 return 0; 1428 } 1429 1430 fs_initcall(init_uprobe_trace); 1431