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 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max 145 * length and relative data location. 146 */ 147 static nokprobe_inline int 148 fetch_store_string(unsigned long addr, void *dest, void *base) 149 { 150 long ret; 151 u32 loc = *(u32 *)dest; 152 int maxlen = get_loc_len(loc); 153 u8 *dst = get_loc_data(dest, base); 154 void __user *src = (void __force __user *) addr; 155 156 if (unlikely(!maxlen)) 157 return -ENOMEM; 158 159 ret = strncpy_from_user(dst, src, maxlen); 160 if (ret >= 0) { 161 if (ret == maxlen) 162 dst[ret - 1] = '\0'; 163 else 164 /* 165 * Include the terminating null byte. In this case it 166 * was copied by strncpy_from_user but not accounted 167 * for in ret. 168 */ 169 ret++; 170 *(u32 *)dest = make_data_loc(ret, (void *)dst - base); 171 } 172 173 return ret; 174 } 175 176 /* Return the length of string -- including null terminal byte */ 177 static nokprobe_inline int 178 fetch_store_strlen(unsigned long addr) 179 { 180 int len; 181 void __user *vaddr = (void __force __user *) addr; 182 183 len = strnlen_user(vaddr, MAX_STRING_SIZE); 184 185 return (len > MAX_STRING_SIZE) ? 0 : len; 186 } 187 188 static unsigned long translate_user_vaddr(unsigned long file_offset) 189 { 190 unsigned long base_addr; 191 struct uprobe_dispatch_data *udd; 192 193 udd = (void *) current->utask->vaddr; 194 195 base_addr = udd->bp_addr - udd->tu->offset; 196 return base_addr + file_offset; 197 } 198 199 /* Note that we don't verify it, since the code does not come from user space */ 200 static int 201 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 202 void *base) 203 { 204 unsigned long val; 205 206 /* 1st stage: get value from context */ 207 switch (code->op) { 208 case FETCH_OP_REG: 209 val = regs_get_register(regs, code->param); 210 break; 211 case FETCH_OP_STACK: 212 val = get_user_stack_nth(regs, code->param); 213 break; 214 case FETCH_OP_STACKP: 215 val = user_stack_pointer(regs); 216 break; 217 case FETCH_OP_RETVAL: 218 val = regs_return_value(regs); 219 break; 220 case FETCH_OP_IMM: 221 val = code->immediate; 222 break; 223 case FETCH_OP_FOFFS: 224 val = translate_user_vaddr(code->immediate); 225 break; 226 default: 227 return -EILSEQ; 228 } 229 code++; 230 231 return process_fetch_insn_bottom(code, val, dest, base); 232 } 233 NOKPROBE_SYMBOL(process_fetch_insn) 234 235 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) 236 { 237 rwlock_init(&filter->rwlock); 238 filter->nr_systemwide = 0; 239 INIT_LIST_HEAD(&filter->perf_events); 240 } 241 242 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 243 { 244 return !filter->nr_systemwide && list_empty(&filter->perf_events); 245 } 246 247 static inline bool is_ret_probe(struct trace_uprobe *tu) 248 { 249 return tu->consumer.ret_handler != NULL; 250 } 251 252 static bool trace_uprobe_is_busy(struct dyn_event *ev) 253 { 254 struct trace_uprobe *tu = to_trace_uprobe(ev); 255 256 return trace_probe_is_enabled(&tu->tp); 257 } 258 259 static bool trace_uprobe_match(const char *system, const char *event, 260 struct dyn_event *ev) 261 { 262 struct trace_uprobe *tu = to_trace_uprobe(ev); 263 264 return strcmp(trace_event_name(&tu->tp.call), event) == 0 && 265 (!system || strcmp(tu->tp.call.class->system, system) == 0); 266 } 267 268 /* 269 * Allocate new trace_uprobe and initialize it (including uprobes). 270 */ 271 static struct trace_uprobe * 272 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 273 { 274 struct trace_uprobe *tu; 275 276 if (!event || !is_good_name(event)) 277 return ERR_PTR(-EINVAL); 278 279 if (!group || !is_good_name(group)) 280 return ERR_PTR(-EINVAL); 281 282 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); 283 if (!tu) 284 return ERR_PTR(-ENOMEM); 285 286 tu->tp.call.class = &tu->tp.class; 287 tu->tp.call.name = kstrdup(event, GFP_KERNEL); 288 if (!tu->tp.call.name) 289 goto error; 290 291 tu->tp.class.system = kstrdup(group, GFP_KERNEL); 292 if (!tu->tp.class.system) 293 goto error; 294 295 dyn_event_init(&tu->devent, &trace_uprobe_ops); 296 INIT_LIST_HEAD(&tu->tp.files); 297 tu->consumer.handler = uprobe_dispatcher; 298 if (is_ret) 299 tu->consumer.ret_handler = uretprobe_dispatcher; 300 init_trace_uprobe_filter(&tu->filter); 301 return tu; 302 303 error: 304 kfree(tu->tp.call.name); 305 kfree(tu); 306 307 return ERR_PTR(-ENOMEM); 308 } 309 310 static void free_trace_uprobe(struct trace_uprobe *tu) 311 { 312 int i; 313 314 if (!tu) 315 return; 316 317 for (i = 0; i < tu->tp.nr_args; i++) 318 traceprobe_free_probe_arg(&tu->tp.args[i]); 319 320 path_put(&tu->path); 321 kfree(tu->tp.call.class->system); 322 kfree(tu->tp.call.name); 323 kfree(tu->filename); 324 kfree(tu); 325 } 326 327 static struct trace_uprobe *find_probe_event(const char *event, const char *group) 328 { 329 struct dyn_event *pos; 330 struct trace_uprobe *tu; 331 332 for_each_trace_uprobe(tu, pos) 333 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 && 334 strcmp(tu->tp.call.class->system, group) == 0) 335 return tu; 336 337 return NULL; 338 } 339 340 /* Unregister a trace_uprobe and probe_event */ 341 static int unregister_trace_uprobe(struct trace_uprobe *tu) 342 { 343 int ret; 344 345 ret = unregister_uprobe_event(tu); 346 if (ret) 347 return ret; 348 349 dyn_event_remove(&tu->devent); 350 free_trace_uprobe(tu); 351 return 0; 352 } 353 354 /* 355 * Uprobe with multiple reference counter is not allowed. i.e. 356 * If inode and offset matches, reference counter offset *must* 357 * match as well. Though, there is one exception: If user is 358 * replacing old trace_uprobe with new one(same group/event), 359 * then we allow same uprobe with new reference counter as far 360 * as the new one does not conflict with any other existing 361 * ones. 362 */ 363 static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new) 364 { 365 struct dyn_event *pos; 366 struct trace_uprobe *tmp, *old = NULL; 367 struct inode *new_inode = d_real_inode(new->path.dentry); 368 369 old = find_probe_event(trace_event_name(&new->tp.call), 370 new->tp.call.class->system); 371 372 for_each_trace_uprobe(tmp, pos) { 373 if ((old ? old != tmp : true) && 374 new_inode == d_real_inode(tmp->path.dentry) && 375 new->offset == tmp->offset && 376 new->ref_ctr_offset != tmp->ref_ctr_offset) { 377 pr_warn("Reference counter offset mismatch."); 378 return ERR_PTR(-EINVAL); 379 } 380 } 381 return old; 382 } 383 384 /* Register a trace_uprobe and probe_event */ 385 static int register_trace_uprobe(struct trace_uprobe *tu) 386 { 387 struct trace_uprobe *old_tu; 388 int ret; 389 390 mutex_lock(&event_mutex); 391 392 /* register as an event */ 393 old_tu = find_old_trace_uprobe(tu); 394 if (IS_ERR(old_tu)) { 395 ret = PTR_ERR(old_tu); 396 goto end; 397 } 398 399 if (old_tu) { 400 /* delete old event */ 401 ret = unregister_trace_uprobe(old_tu); 402 if (ret) 403 goto end; 404 } 405 406 ret = register_uprobe_event(tu); 407 if (ret) { 408 pr_warn("Failed to register probe event(%d)\n", ret); 409 goto end; 410 } 411 412 dyn_event_add(&tu->devent); 413 414 end: 415 mutex_unlock(&event_mutex); 416 417 return ret; 418 } 419 420 /* 421 * Argument syntax: 422 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] 423 * 424 * - Remove uprobe: -:[GRP/]EVENT 425 */ 426 static int trace_uprobe_create(int argc, const char **argv) 427 { 428 struct trace_uprobe *tu; 429 const char *event = NULL, *group = UPROBE_EVENT_SYSTEM; 430 char *arg, *filename, *rctr, *rctr_end, *tmp; 431 char buf[MAX_EVENT_NAME_LEN]; 432 struct path path; 433 unsigned long offset, ref_ctr_offset; 434 bool is_return = false; 435 int i, ret; 436 437 ret = 0; 438 ref_ctr_offset = 0; 439 440 /* argc must be >= 1 */ 441 if (argv[0][0] == 'r') 442 is_return = true; 443 else if (argv[0][0] != 'p' || argc < 2) 444 return -ECANCELED; 445 446 if (argv[0][1] == ':') 447 event = &argv[0][2]; 448 449 if (!strchr(argv[1], '/')) 450 return -ECANCELED; 451 452 filename = kstrdup(argv[1], GFP_KERNEL); 453 if (!filename) 454 return -ENOMEM; 455 456 /* Find the last occurrence, in case the path contains ':' too. */ 457 arg = strrchr(filename, ':'); 458 if (!arg || !isdigit(arg[1])) { 459 kfree(filename); 460 return -ECANCELED; 461 } 462 463 *arg++ = '\0'; 464 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 465 if (ret) { 466 kfree(filename); 467 return ret; 468 } 469 if (!d_is_reg(path.dentry)) { 470 ret = -EINVAL; 471 goto fail_address_parse; 472 } 473 474 /* Parse reference counter offset if specified. */ 475 rctr = strchr(arg, '('); 476 if (rctr) { 477 rctr_end = strchr(rctr, ')'); 478 if (rctr > rctr_end || *(rctr_end + 1) != 0) { 479 ret = -EINVAL; 480 pr_info("Invalid reference counter offset.\n"); 481 goto fail_address_parse; 482 } 483 484 *rctr++ = '\0'; 485 *rctr_end = '\0'; 486 ret = kstrtoul(rctr, 0, &ref_ctr_offset); 487 if (ret) { 488 pr_info("Invalid reference counter offset.\n"); 489 goto fail_address_parse; 490 } 491 } 492 493 /* Parse uprobe offset. */ 494 ret = kstrtoul(arg, 0, &offset); 495 if (ret) 496 goto fail_address_parse; 497 498 argc -= 2; 499 argv += 2; 500 501 /* setup a probe */ 502 if (event) { 503 ret = traceprobe_parse_event_name(&event, &group, buf); 504 if (ret) 505 goto fail_address_parse; 506 } else { 507 char *tail; 508 char *ptr; 509 510 tail = kstrdup(kbasename(filename), GFP_KERNEL); 511 if (!tail) { 512 ret = -ENOMEM; 513 goto fail_address_parse; 514 } 515 516 ptr = strpbrk(tail, ".-_"); 517 if (ptr) 518 *ptr = '\0'; 519 520 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 521 event = buf; 522 kfree(tail); 523 } 524 525 tu = alloc_trace_uprobe(group, event, argc, is_return); 526 if (IS_ERR(tu)) { 527 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); 528 ret = PTR_ERR(tu); 529 goto fail_address_parse; 530 } 531 tu->offset = offset; 532 tu->ref_ctr_offset = ref_ctr_offset; 533 tu->path = path; 534 tu->filename = filename; 535 536 /* parse arguments */ 537 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 538 tmp = kstrdup(argv[i], GFP_KERNEL); 539 if (!tmp) { 540 ret = -ENOMEM; 541 goto error; 542 } 543 544 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp, 545 is_return ? TPARG_FL_RETURN : 0); 546 kfree(tmp); 547 if (ret) 548 goto error; 549 } 550 551 ret = register_trace_uprobe(tu); 552 if (ret) 553 goto error; 554 return 0; 555 556 error: 557 free_trace_uprobe(tu); 558 return ret; 559 560 fail_address_parse: 561 path_put(&path); 562 kfree(filename); 563 564 pr_info("Failed to parse address or file.\n"); 565 566 return ret; 567 } 568 569 static int create_or_delete_trace_uprobe(int argc, char **argv) 570 { 571 int ret; 572 573 if (argv[0][0] == '-') 574 return dyn_event_release(argc, argv, &trace_uprobe_ops); 575 576 ret = trace_uprobe_create(argc, (const char **)argv); 577 return ret == -ECANCELED ? -EINVAL : ret; 578 } 579 580 static int trace_uprobe_release(struct dyn_event *ev) 581 { 582 struct trace_uprobe *tu = to_trace_uprobe(ev); 583 584 return unregister_trace_uprobe(tu); 585 } 586 587 /* Probes listing interfaces */ 588 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev) 589 { 590 struct trace_uprobe *tu = to_trace_uprobe(ev); 591 char c = is_ret_probe(tu) ? 'r' : 'p'; 592 int i; 593 594 seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system, 595 trace_event_name(&tu->tp.call), tu->filename, 596 (int)(sizeof(void *) * 2), tu->offset); 597 598 if (tu->ref_ctr_offset) 599 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset); 600 601 for (i = 0; i < tu->tp.nr_args; i++) 602 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 603 604 seq_putc(m, '\n'); 605 return 0; 606 } 607 608 static int probes_seq_show(struct seq_file *m, void *v) 609 { 610 struct dyn_event *ev = v; 611 612 if (!is_trace_uprobe(ev)) 613 return 0; 614 615 return trace_uprobe_show(m, ev); 616 } 617 618 static const struct seq_operations probes_seq_op = { 619 .start = dyn_event_seq_start, 620 .next = dyn_event_seq_next, 621 .stop = dyn_event_seq_stop, 622 .show = probes_seq_show 623 }; 624 625 static int probes_open(struct inode *inode, struct file *file) 626 { 627 int ret; 628 629 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 630 ret = dyn_events_release_all(&trace_uprobe_ops); 631 if (ret) 632 return ret; 633 } 634 635 return seq_open(file, &probes_seq_op); 636 } 637 638 static ssize_t probes_write(struct file *file, const char __user *buffer, 639 size_t count, loff_t *ppos) 640 { 641 return trace_parse_run_command(file, buffer, count, ppos, 642 create_or_delete_trace_uprobe); 643 } 644 645 static const struct file_operations uprobe_events_ops = { 646 .owner = THIS_MODULE, 647 .open = probes_open, 648 .read = seq_read, 649 .llseek = seq_lseek, 650 .release = seq_release, 651 .write = probes_write, 652 }; 653 654 /* Probes profiling interfaces */ 655 static int probes_profile_seq_show(struct seq_file *m, void *v) 656 { 657 struct dyn_event *ev = v; 658 struct trace_uprobe *tu; 659 660 if (!is_trace_uprobe(ev)) 661 return 0; 662 663 tu = to_trace_uprobe(ev); 664 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 665 trace_event_name(&tu->tp.call), tu->nhit); 666 return 0; 667 } 668 669 static const struct seq_operations profile_seq_op = { 670 .start = dyn_event_seq_start, 671 .next = dyn_event_seq_next, 672 .stop = dyn_event_seq_stop, 673 .show = probes_profile_seq_show 674 }; 675 676 static int profile_open(struct inode *inode, struct file *file) 677 { 678 return seq_open(file, &profile_seq_op); 679 } 680 681 static const struct file_operations uprobe_profile_ops = { 682 .owner = THIS_MODULE, 683 .open = profile_open, 684 .read = seq_read, 685 .llseek = seq_lseek, 686 .release = seq_release, 687 }; 688 689 struct uprobe_cpu_buffer { 690 struct mutex mutex; 691 void *buf; 692 }; 693 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 694 static int uprobe_buffer_refcnt; 695 696 static int uprobe_buffer_init(void) 697 { 698 int cpu, err_cpu; 699 700 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 701 if (uprobe_cpu_buffer == NULL) 702 return -ENOMEM; 703 704 for_each_possible_cpu(cpu) { 705 struct page *p = alloc_pages_node(cpu_to_node(cpu), 706 GFP_KERNEL, 0); 707 if (p == NULL) { 708 err_cpu = cpu; 709 goto err; 710 } 711 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 712 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 713 } 714 715 return 0; 716 717 err: 718 for_each_possible_cpu(cpu) { 719 if (cpu == err_cpu) 720 break; 721 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 722 } 723 724 free_percpu(uprobe_cpu_buffer); 725 return -ENOMEM; 726 } 727 728 static int uprobe_buffer_enable(void) 729 { 730 int ret = 0; 731 732 BUG_ON(!mutex_is_locked(&event_mutex)); 733 734 if (uprobe_buffer_refcnt++ == 0) { 735 ret = uprobe_buffer_init(); 736 if (ret < 0) 737 uprobe_buffer_refcnt--; 738 } 739 740 return ret; 741 } 742 743 static void uprobe_buffer_disable(void) 744 { 745 int cpu; 746 747 BUG_ON(!mutex_is_locked(&event_mutex)); 748 749 if (--uprobe_buffer_refcnt == 0) { 750 for_each_possible_cpu(cpu) 751 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 752 cpu)->buf); 753 754 free_percpu(uprobe_cpu_buffer); 755 uprobe_cpu_buffer = NULL; 756 } 757 } 758 759 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 760 { 761 struct uprobe_cpu_buffer *ucb; 762 int cpu; 763 764 cpu = raw_smp_processor_id(); 765 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 766 767 /* 768 * Use per-cpu buffers for fastest access, but we might migrate 769 * so the mutex makes sure we have sole access to it. 770 */ 771 mutex_lock(&ucb->mutex); 772 773 return ucb; 774 } 775 776 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 777 { 778 mutex_unlock(&ucb->mutex); 779 } 780 781 static void __uprobe_trace_func(struct trace_uprobe *tu, 782 unsigned long func, struct pt_regs *regs, 783 struct uprobe_cpu_buffer *ucb, int dsize, 784 struct trace_event_file *trace_file) 785 { 786 struct uprobe_trace_entry_head *entry; 787 struct ring_buffer_event *event; 788 struct ring_buffer *buffer; 789 void *data; 790 int size, esize; 791 struct trace_event_call *call = &tu->tp.call; 792 793 WARN_ON(call != trace_file->event_call); 794 795 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 796 return; 797 798 if (trace_trigger_soft_disabled(trace_file)) 799 return; 800 801 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 802 size = esize + tu->tp.size + dsize; 803 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 804 call->event.type, size, 0, 0); 805 if (!event) 806 return; 807 808 entry = ring_buffer_event_data(event); 809 if (is_ret_probe(tu)) { 810 entry->vaddr[0] = func; 811 entry->vaddr[1] = instruction_pointer(regs); 812 data = DATAOF_TRACE_ENTRY(entry, true); 813 } else { 814 entry->vaddr[0] = instruction_pointer(regs); 815 data = DATAOF_TRACE_ENTRY(entry, false); 816 } 817 818 memcpy(data, ucb->buf, tu->tp.size + dsize); 819 820 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); 821 } 822 823 /* uprobe handler */ 824 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 825 struct uprobe_cpu_buffer *ucb, int dsize) 826 { 827 struct event_file_link *link; 828 829 if (is_ret_probe(tu)) 830 return 0; 831 832 rcu_read_lock(); 833 list_for_each_entry_rcu(link, &tu->tp.files, list) 834 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 835 rcu_read_unlock(); 836 837 return 0; 838 } 839 840 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 841 struct pt_regs *regs, 842 struct uprobe_cpu_buffer *ucb, int dsize) 843 { 844 struct event_file_link *link; 845 846 rcu_read_lock(); 847 list_for_each_entry_rcu(link, &tu->tp.files, list) 848 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 849 rcu_read_unlock(); 850 } 851 852 /* Event entry printers */ 853 static enum print_line_t 854 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 855 { 856 struct uprobe_trace_entry_head *entry; 857 struct trace_seq *s = &iter->seq; 858 struct trace_uprobe *tu; 859 u8 *data; 860 861 entry = (struct uprobe_trace_entry_head *)iter->ent; 862 tu = container_of(event, struct trace_uprobe, tp.call.event); 863 864 if (is_ret_probe(tu)) { 865 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 866 trace_event_name(&tu->tp.call), 867 entry->vaddr[1], entry->vaddr[0]); 868 data = DATAOF_TRACE_ENTRY(entry, true); 869 } else { 870 trace_seq_printf(s, "%s: (0x%lx)", 871 trace_event_name(&tu->tp.call), 872 entry->vaddr[0]); 873 data = DATAOF_TRACE_ENTRY(entry, false); 874 } 875 876 if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0) 877 goto out; 878 879 trace_seq_putc(s, '\n'); 880 881 out: 882 return trace_handle_return(s); 883 } 884 885 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 886 enum uprobe_filter_ctx ctx, 887 struct mm_struct *mm); 888 889 static int 890 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, 891 filter_func_t filter) 892 { 893 bool enabled = trace_probe_is_enabled(&tu->tp); 894 struct event_file_link *link = NULL; 895 int ret; 896 897 if (file) { 898 if (tu->tp.flags & TP_FLAG_PROFILE) 899 return -EINTR; 900 901 link = kmalloc(sizeof(*link), GFP_KERNEL); 902 if (!link) 903 return -ENOMEM; 904 905 link->file = file; 906 list_add_tail_rcu(&link->list, &tu->tp.files); 907 908 tu->tp.flags |= TP_FLAG_TRACE; 909 } else { 910 if (tu->tp.flags & TP_FLAG_TRACE) 911 return -EINTR; 912 913 tu->tp.flags |= TP_FLAG_PROFILE; 914 } 915 916 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 917 918 if (enabled) 919 return 0; 920 921 ret = uprobe_buffer_enable(); 922 if (ret) 923 goto err_flags; 924 925 tu->consumer.filter = filter; 926 tu->inode = d_real_inode(tu->path.dentry); 927 if (tu->ref_ctr_offset) { 928 ret = uprobe_register_refctr(tu->inode, tu->offset, 929 tu->ref_ctr_offset, &tu->consumer); 930 } else { 931 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 932 } 933 934 if (ret) 935 goto err_buffer; 936 937 return 0; 938 939 err_buffer: 940 uprobe_buffer_disable(); 941 942 err_flags: 943 if (file) { 944 list_del(&link->list); 945 kfree(link); 946 tu->tp.flags &= ~TP_FLAG_TRACE; 947 } else { 948 tu->tp.flags &= ~TP_FLAG_PROFILE; 949 } 950 return ret; 951 } 952 953 static void 954 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) 955 { 956 if (!trace_probe_is_enabled(&tu->tp)) 957 return; 958 959 if (file) { 960 struct event_file_link *link; 961 962 link = find_event_file_link(&tu->tp, file); 963 if (!link) 964 return; 965 966 list_del_rcu(&link->list); 967 /* synchronize with u{,ret}probe_trace_func */ 968 synchronize_rcu(); 969 kfree(link); 970 971 if (!list_empty(&tu->tp.files)) 972 return; 973 } 974 975 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 976 977 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 978 tu->inode = NULL; 979 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 980 981 uprobe_buffer_disable(); 982 } 983 984 static int uprobe_event_define_fields(struct trace_event_call *event_call) 985 { 986 int ret, size; 987 struct uprobe_trace_entry_head field; 988 struct trace_uprobe *tu = event_call->data; 989 990 if (is_ret_probe(tu)) { 991 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 992 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 993 size = SIZEOF_TRACE_ENTRY(true); 994 } else { 995 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 996 size = SIZEOF_TRACE_ENTRY(false); 997 } 998 999 return traceprobe_define_arg_fields(event_call, size, &tu->tp); 1000 } 1001 1002 #ifdef CONFIG_PERF_EVENTS 1003 static bool 1004 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1005 { 1006 struct perf_event *event; 1007 1008 if (filter->nr_systemwide) 1009 return true; 1010 1011 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1012 if (event->hw.target->mm == mm) 1013 return true; 1014 } 1015 1016 return false; 1017 } 1018 1019 static inline bool 1020 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1021 { 1022 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1023 } 1024 1025 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1026 { 1027 bool done; 1028 1029 write_lock(&tu->filter.rwlock); 1030 if (event->hw.target) { 1031 list_del(&event->hw.tp_list); 1032 done = tu->filter.nr_systemwide || 1033 (event->hw.target->flags & PF_EXITING) || 1034 uprobe_filter_event(tu, event); 1035 } else { 1036 tu->filter.nr_systemwide--; 1037 done = tu->filter.nr_systemwide; 1038 } 1039 write_unlock(&tu->filter.rwlock); 1040 1041 if (!done) 1042 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1043 1044 return 0; 1045 } 1046 1047 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1048 { 1049 bool done; 1050 int err; 1051 1052 write_lock(&tu->filter.rwlock); 1053 if (event->hw.target) { 1054 /* 1055 * event->parent != NULL means copy_process(), we can avoid 1056 * uprobe_apply(). current->mm must be probed and we can rely 1057 * on dup_mmap() which preserves the already installed bp's. 1058 * 1059 * attr.enable_on_exec means that exec/mmap will install the 1060 * breakpoints we need. 1061 */ 1062 done = tu->filter.nr_systemwide || 1063 event->parent || event->attr.enable_on_exec || 1064 uprobe_filter_event(tu, event); 1065 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1066 } else { 1067 done = tu->filter.nr_systemwide; 1068 tu->filter.nr_systemwide++; 1069 } 1070 write_unlock(&tu->filter.rwlock); 1071 1072 err = 0; 1073 if (!done) { 1074 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1075 if (err) 1076 uprobe_perf_close(tu, event); 1077 } 1078 return err; 1079 } 1080 1081 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1082 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1083 { 1084 struct trace_uprobe *tu; 1085 int ret; 1086 1087 tu = container_of(uc, struct trace_uprobe, consumer); 1088 read_lock(&tu->filter.rwlock); 1089 ret = __uprobe_perf_filter(&tu->filter, mm); 1090 read_unlock(&tu->filter.rwlock); 1091 1092 return ret; 1093 } 1094 1095 static void __uprobe_perf_func(struct trace_uprobe *tu, 1096 unsigned long func, struct pt_regs *regs, 1097 struct uprobe_cpu_buffer *ucb, int dsize) 1098 { 1099 struct trace_event_call *call = &tu->tp.call; 1100 struct uprobe_trace_entry_head *entry; 1101 struct hlist_head *head; 1102 void *data; 1103 int size, esize; 1104 int rctx; 1105 1106 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1107 return; 1108 1109 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1110 1111 size = esize + tu->tp.size + dsize; 1112 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1113 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1114 return; 1115 1116 preempt_disable(); 1117 head = this_cpu_ptr(call->perf_events); 1118 if (hlist_empty(head)) 1119 goto out; 1120 1121 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1122 if (!entry) 1123 goto out; 1124 1125 if (is_ret_probe(tu)) { 1126 entry->vaddr[0] = func; 1127 entry->vaddr[1] = instruction_pointer(regs); 1128 data = DATAOF_TRACE_ENTRY(entry, true); 1129 } else { 1130 entry->vaddr[0] = instruction_pointer(regs); 1131 data = DATAOF_TRACE_ENTRY(entry, false); 1132 } 1133 1134 memcpy(data, ucb->buf, tu->tp.size + dsize); 1135 1136 if (size - esize > tu->tp.size + dsize) { 1137 int len = tu->tp.size + dsize; 1138 1139 memset(data + len, 0, size - esize - len); 1140 } 1141 1142 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1143 head, NULL); 1144 out: 1145 preempt_enable(); 1146 } 1147 1148 /* uprobe profile handler */ 1149 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1150 struct uprobe_cpu_buffer *ucb, int dsize) 1151 { 1152 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1153 return UPROBE_HANDLER_REMOVE; 1154 1155 if (!is_ret_probe(tu)) 1156 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1157 return 0; 1158 } 1159 1160 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1161 struct pt_regs *regs, 1162 struct uprobe_cpu_buffer *ucb, int dsize) 1163 { 1164 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1165 } 1166 1167 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type, 1168 const char **filename, u64 *probe_offset, 1169 bool perf_type_tracepoint) 1170 { 1171 const char *pevent = trace_event_name(event->tp_event); 1172 const char *group = event->tp_event->class->system; 1173 struct trace_uprobe *tu; 1174 1175 if (perf_type_tracepoint) 1176 tu = find_probe_event(pevent, group); 1177 else 1178 tu = event->tp_event->data; 1179 if (!tu) 1180 return -EINVAL; 1181 1182 *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE 1183 : BPF_FD_TYPE_UPROBE; 1184 *filename = tu->filename; 1185 *probe_offset = tu->offset; 1186 return 0; 1187 } 1188 #endif /* CONFIG_PERF_EVENTS */ 1189 1190 static int 1191 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, 1192 void *data) 1193 { 1194 struct trace_uprobe *tu = event->data; 1195 struct trace_event_file *file = data; 1196 1197 switch (type) { 1198 case TRACE_REG_REGISTER: 1199 return probe_event_enable(tu, file, NULL); 1200 1201 case TRACE_REG_UNREGISTER: 1202 probe_event_disable(tu, file); 1203 return 0; 1204 1205 #ifdef CONFIG_PERF_EVENTS 1206 case TRACE_REG_PERF_REGISTER: 1207 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1208 1209 case TRACE_REG_PERF_UNREGISTER: 1210 probe_event_disable(tu, NULL); 1211 return 0; 1212 1213 case TRACE_REG_PERF_OPEN: 1214 return uprobe_perf_open(tu, data); 1215 1216 case TRACE_REG_PERF_CLOSE: 1217 return uprobe_perf_close(tu, data); 1218 1219 #endif 1220 default: 1221 return 0; 1222 } 1223 return 0; 1224 } 1225 1226 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1227 { 1228 struct trace_uprobe *tu; 1229 struct uprobe_dispatch_data udd; 1230 struct uprobe_cpu_buffer *ucb; 1231 int dsize, esize; 1232 int ret = 0; 1233 1234 1235 tu = container_of(con, struct trace_uprobe, consumer); 1236 tu->nhit++; 1237 1238 udd.tu = tu; 1239 udd.bp_addr = instruction_pointer(regs); 1240 1241 current->utask->vaddr = (unsigned long) &udd; 1242 1243 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1244 return 0; 1245 1246 dsize = __get_data_size(&tu->tp, regs); 1247 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1248 1249 ucb = uprobe_buffer_get(); 1250 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1251 1252 if (tu->tp.flags & TP_FLAG_TRACE) 1253 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1254 1255 #ifdef CONFIG_PERF_EVENTS 1256 if (tu->tp.flags & TP_FLAG_PROFILE) 1257 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1258 #endif 1259 uprobe_buffer_put(ucb); 1260 return ret; 1261 } 1262 1263 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1264 unsigned long func, struct pt_regs *regs) 1265 { 1266 struct trace_uprobe *tu; 1267 struct uprobe_dispatch_data udd; 1268 struct uprobe_cpu_buffer *ucb; 1269 int dsize, esize; 1270 1271 tu = container_of(con, struct trace_uprobe, consumer); 1272 1273 udd.tu = tu; 1274 udd.bp_addr = func; 1275 1276 current->utask->vaddr = (unsigned long) &udd; 1277 1278 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1279 return 0; 1280 1281 dsize = __get_data_size(&tu->tp, regs); 1282 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1283 1284 ucb = uprobe_buffer_get(); 1285 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1286 1287 if (tu->tp.flags & TP_FLAG_TRACE) 1288 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1289 1290 #ifdef CONFIG_PERF_EVENTS 1291 if (tu->tp.flags & TP_FLAG_PROFILE) 1292 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1293 #endif 1294 uprobe_buffer_put(ucb); 1295 return 0; 1296 } 1297 1298 static struct trace_event_functions uprobe_funcs = { 1299 .trace = print_uprobe_event 1300 }; 1301 1302 static inline void init_trace_event_call(struct trace_uprobe *tu, 1303 struct trace_event_call *call) 1304 { 1305 INIT_LIST_HEAD(&call->class->fields); 1306 call->event.funcs = &uprobe_funcs; 1307 call->class->define_fields = uprobe_event_define_fields; 1308 1309 call->flags = TRACE_EVENT_FL_UPROBE; 1310 call->class->reg = trace_uprobe_register; 1311 call->data = tu; 1312 } 1313 1314 static int register_uprobe_event(struct trace_uprobe *tu) 1315 { 1316 struct trace_event_call *call = &tu->tp.call; 1317 int ret = 0; 1318 1319 init_trace_event_call(tu, call); 1320 1321 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1322 return -ENOMEM; 1323 1324 ret = register_trace_event(&call->event); 1325 if (!ret) { 1326 kfree(call->print_fmt); 1327 return -ENODEV; 1328 } 1329 1330 ret = trace_add_event_call(call); 1331 1332 if (ret) { 1333 pr_info("Failed to register uprobe event: %s\n", 1334 trace_event_name(call)); 1335 kfree(call->print_fmt); 1336 unregister_trace_event(&call->event); 1337 } 1338 1339 return ret; 1340 } 1341 1342 static int unregister_uprobe_event(struct trace_uprobe *tu) 1343 { 1344 int ret; 1345 1346 /* tu->event is unregistered in trace_remove_event_call() */ 1347 ret = trace_remove_event_call(&tu->tp.call); 1348 if (ret) 1349 return ret; 1350 kfree(tu->tp.call.print_fmt); 1351 tu->tp.call.print_fmt = NULL; 1352 return 0; 1353 } 1354 1355 #ifdef CONFIG_PERF_EVENTS 1356 struct trace_event_call * 1357 create_local_trace_uprobe(char *name, unsigned long offs, 1358 unsigned long ref_ctr_offset, bool is_return) 1359 { 1360 struct trace_uprobe *tu; 1361 struct path path; 1362 int ret; 1363 1364 ret = kern_path(name, LOOKUP_FOLLOW, &path); 1365 if (ret) 1366 return ERR_PTR(ret); 1367 1368 if (!d_is_reg(path.dentry)) { 1369 path_put(&path); 1370 return ERR_PTR(-EINVAL); 1371 } 1372 1373 /* 1374 * local trace_kprobes are not added to dyn_event, so they are never 1375 * searched in find_trace_kprobe(). Therefore, there is no concern of 1376 * duplicated name "DUMMY_EVENT" here. 1377 */ 1378 tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0, 1379 is_return); 1380 1381 if (IS_ERR(tu)) { 1382 pr_info("Failed to allocate trace_uprobe.(%d)\n", 1383 (int)PTR_ERR(tu)); 1384 path_put(&path); 1385 return ERR_CAST(tu); 1386 } 1387 1388 tu->offset = offs; 1389 tu->path = path; 1390 tu->ref_ctr_offset = ref_ctr_offset; 1391 tu->filename = kstrdup(name, GFP_KERNEL); 1392 init_trace_event_call(tu, &tu->tp.call); 1393 1394 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) { 1395 ret = -ENOMEM; 1396 goto error; 1397 } 1398 1399 return &tu->tp.call; 1400 error: 1401 free_trace_uprobe(tu); 1402 return ERR_PTR(ret); 1403 } 1404 1405 void destroy_local_trace_uprobe(struct trace_event_call *event_call) 1406 { 1407 struct trace_uprobe *tu; 1408 1409 tu = container_of(event_call, struct trace_uprobe, tp.call); 1410 1411 kfree(tu->tp.call.print_fmt); 1412 tu->tp.call.print_fmt = NULL; 1413 1414 free_trace_uprobe(tu); 1415 } 1416 #endif /* CONFIG_PERF_EVENTS */ 1417 1418 /* Make a trace interface for controling probe points */ 1419 static __init int init_uprobe_trace(void) 1420 { 1421 struct dentry *d_tracer; 1422 int ret; 1423 1424 ret = dyn_event_register(&trace_uprobe_ops); 1425 if (ret) 1426 return ret; 1427 1428 d_tracer = tracing_init_dentry(); 1429 if (IS_ERR(d_tracer)) 1430 return 0; 1431 1432 trace_create_file("uprobe_events", 0644, d_tracer, 1433 NULL, &uprobe_events_ops); 1434 /* Profile interface */ 1435 trace_create_file("uprobe_profile", 0444, d_tracer, 1436 NULL, &uprobe_profile_ops); 1437 return 0; 1438 } 1439 1440 fs_initcall(init_uprobe_trace); 1441