1 /* 2 * uprobes-based tracing events 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 16 * 17 * Copyright (C) IBM Corporation, 2010-2012 18 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> 19 */ 20 21 #include <linux/module.h> 22 #include <linux/uaccess.h> 23 #include <linux/uprobes.h> 24 #include <linux/namei.h> 25 #include <linux/string.h> 26 27 #include "trace_probe.h" 28 29 #define UPROBE_EVENT_SYSTEM "uprobes" 30 31 struct uprobe_trace_entry_head { 32 struct trace_entry ent; 33 unsigned long vaddr[]; 34 }; 35 36 #define SIZEOF_TRACE_ENTRY(is_return) \ 37 (sizeof(struct uprobe_trace_entry_head) + \ 38 sizeof(unsigned long) * (is_return ? 2 : 1)) 39 40 #define DATAOF_TRACE_ENTRY(entry, is_return) \ 41 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) 42 43 struct trace_uprobe_filter { 44 rwlock_t rwlock; 45 int nr_systemwide; 46 struct list_head perf_events; 47 }; 48 49 /* 50 * uprobe event core functions 51 */ 52 struct trace_uprobe { 53 struct list_head list; 54 struct trace_uprobe_filter filter; 55 struct uprobe_consumer consumer; 56 struct inode *inode; 57 char *filename; 58 unsigned long offset; 59 unsigned long nhit; 60 struct trace_probe tp; 61 }; 62 63 #define SIZEOF_TRACE_UPROBE(n) \ 64 (offsetof(struct trace_uprobe, tp.args) + \ 65 (sizeof(struct probe_arg) * (n))) 66 67 static int register_uprobe_event(struct trace_uprobe *tu); 68 static int unregister_uprobe_event(struct trace_uprobe *tu); 69 70 static DEFINE_MUTEX(uprobe_lock); 71 static LIST_HEAD(uprobe_list); 72 73 struct uprobe_dispatch_data { 74 struct trace_uprobe *tu; 75 unsigned long bp_addr; 76 }; 77 78 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); 79 static int uretprobe_dispatcher(struct uprobe_consumer *con, 80 unsigned long func, struct pt_regs *regs); 81 82 #ifdef CONFIG_STACK_GROWSUP 83 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 84 { 85 return addr - (n * sizeof(long)); 86 } 87 #else 88 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 89 { 90 return addr + (n * sizeof(long)); 91 } 92 #endif 93 94 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) 95 { 96 unsigned long ret; 97 unsigned long addr = user_stack_pointer(regs); 98 99 addr = adjust_stack_addr(addr, n); 100 101 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) 102 return 0; 103 104 return ret; 105 } 106 107 /* 108 * Uprobes-specific fetch functions 109 */ 110 #define DEFINE_FETCH_stack(type) \ 111 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \ 112 void *offset, void *dest) \ 113 { \ 114 *(type *)dest = (type)get_user_stack_nth(regs, \ 115 ((unsigned long)offset)); \ 116 } 117 DEFINE_BASIC_FETCH_FUNCS(stack) 118 /* No string on the stack entry */ 119 #define fetch_stack_string NULL 120 #define fetch_stack_string_size NULL 121 122 #define DEFINE_FETCH_memory(type) \ 123 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \ 124 void *addr, void *dest) \ 125 { \ 126 type retval; \ 127 void __user *vaddr = (void __force __user *) addr; \ 128 \ 129 if (copy_from_user(&retval, vaddr, sizeof(type))) \ 130 *(type *)dest = 0; \ 131 else \ 132 *(type *) dest = retval; \ 133 } 134 DEFINE_BASIC_FETCH_FUNCS(memory) 135 /* 136 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max 137 * length and relative data location. 138 */ 139 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, 140 void *addr, void *dest) 141 { 142 long ret; 143 u32 rloc = *(u32 *)dest; 144 int maxlen = get_rloc_len(rloc); 145 u8 *dst = get_rloc_data(dest); 146 void __user *src = (void __force __user *) addr; 147 148 if (!maxlen) 149 return; 150 151 ret = strncpy_from_user(dst, src, maxlen); 152 153 if (ret < 0) { /* Failed to fetch string */ 154 ((u8 *)get_rloc_data(dest))[0] = '\0'; 155 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc)); 156 } else { 157 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc)); 158 } 159 } 160 161 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, 162 void *addr, void *dest) 163 { 164 int len; 165 void __user *vaddr = (void __force __user *) addr; 166 167 len = strnlen_user(vaddr, MAX_STRING_SIZE); 168 169 if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */ 170 *(u32 *)dest = 0; 171 else 172 *(u32 *)dest = len; 173 } 174 175 static unsigned long translate_user_vaddr(void *file_offset) 176 { 177 unsigned long base_addr; 178 struct uprobe_dispatch_data *udd; 179 180 udd = (void *) current->utask->vaddr; 181 182 base_addr = udd->bp_addr - udd->tu->offset; 183 return base_addr + (unsigned long)file_offset; 184 } 185 186 #define DEFINE_FETCH_file_offset(type) \ 187 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs, \ 188 void *offset, void *dest)\ 189 { \ 190 void *vaddr = (void *)translate_user_vaddr(offset); \ 191 \ 192 FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \ 193 } 194 DEFINE_BASIC_FETCH_FUNCS(file_offset) 195 DEFINE_FETCH_file_offset(string) 196 DEFINE_FETCH_file_offset(string_size) 197 198 /* Fetch type information table */ 199 static const struct fetch_type uprobes_fetch_type_table[] = { 200 /* Special types */ 201 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string, 202 sizeof(u32), 1, "__data_loc char[]"), 203 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32, 204 string_size, sizeof(u32), 0, "u32"), 205 /* Basic types */ 206 ASSIGN_FETCH_TYPE(u8, u8, 0), 207 ASSIGN_FETCH_TYPE(u16, u16, 0), 208 ASSIGN_FETCH_TYPE(u32, u32, 0), 209 ASSIGN_FETCH_TYPE(u64, u64, 0), 210 ASSIGN_FETCH_TYPE(s8, u8, 1), 211 ASSIGN_FETCH_TYPE(s16, u16, 1), 212 ASSIGN_FETCH_TYPE(s32, u32, 1), 213 ASSIGN_FETCH_TYPE(s64, u64, 1), 214 215 ASSIGN_FETCH_TYPE_END 216 }; 217 218 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) 219 { 220 rwlock_init(&filter->rwlock); 221 filter->nr_systemwide = 0; 222 INIT_LIST_HEAD(&filter->perf_events); 223 } 224 225 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 226 { 227 return !filter->nr_systemwide && list_empty(&filter->perf_events); 228 } 229 230 static inline bool is_ret_probe(struct trace_uprobe *tu) 231 { 232 return tu->consumer.ret_handler != NULL; 233 } 234 235 /* 236 * Allocate new trace_uprobe and initialize it (including uprobes). 237 */ 238 static struct trace_uprobe * 239 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 240 { 241 struct trace_uprobe *tu; 242 243 if (!event || !is_good_name(event)) 244 return ERR_PTR(-EINVAL); 245 246 if (!group || !is_good_name(group)) 247 return ERR_PTR(-EINVAL); 248 249 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); 250 if (!tu) 251 return ERR_PTR(-ENOMEM); 252 253 tu->tp.call.class = &tu->tp.class; 254 tu->tp.call.name = kstrdup(event, GFP_KERNEL); 255 if (!tu->tp.call.name) 256 goto error; 257 258 tu->tp.class.system = kstrdup(group, GFP_KERNEL); 259 if (!tu->tp.class.system) 260 goto error; 261 262 INIT_LIST_HEAD(&tu->list); 263 INIT_LIST_HEAD(&tu->tp.files); 264 tu->consumer.handler = uprobe_dispatcher; 265 if (is_ret) 266 tu->consumer.ret_handler = uretprobe_dispatcher; 267 init_trace_uprobe_filter(&tu->filter); 268 return tu; 269 270 error: 271 kfree(tu->tp.call.name); 272 kfree(tu); 273 274 return ERR_PTR(-ENOMEM); 275 } 276 277 static void free_trace_uprobe(struct trace_uprobe *tu) 278 { 279 int i; 280 281 for (i = 0; i < tu->tp.nr_args; i++) 282 traceprobe_free_probe_arg(&tu->tp.args[i]); 283 284 iput(tu->inode); 285 kfree(tu->tp.call.class->system); 286 kfree(tu->tp.call.name); 287 kfree(tu->filename); 288 kfree(tu); 289 } 290 291 static struct trace_uprobe *find_probe_event(const char *event, const char *group) 292 { 293 struct trace_uprobe *tu; 294 295 list_for_each_entry(tu, &uprobe_list, list) 296 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 && 297 strcmp(tu->tp.call.class->system, group) == 0) 298 return tu; 299 300 return NULL; 301 } 302 303 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ 304 static int unregister_trace_uprobe(struct trace_uprobe *tu) 305 { 306 int ret; 307 308 ret = unregister_uprobe_event(tu); 309 if (ret) 310 return ret; 311 312 list_del(&tu->list); 313 free_trace_uprobe(tu); 314 return 0; 315 } 316 317 /* Register a trace_uprobe and probe_event */ 318 static int register_trace_uprobe(struct trace_uprobe *tu) 319 { 320 struct trace_uprobe *old_tu; 321 int ret; 322 323 mutex_lock(&uprobe_lock); 324 325 /* register as an event */ 326 old_tu = find_probe_event(trace_event_name(&tu->tp.call), 327 tu->tp.call.class->system); 328 if (old_tu) { 329 /* delete old event */ 330 ret = unregister_trace_uprobe(old_tu); 331 if (ret) 332 goto end; 333 } 334 335 ret = register_uprobe_event(tu); 336 if (ret) { 337 pr_warning("Failed to register probe event(%d)\n", ret); 338 goto end; 339 } 340 341 list_add_tail(&tu->list, &uprobe_list); 342 343 end: 344 mutex_unlock(&uprobe_lock); 345 346 return ret; 347 } 348 349 /* 350 * Argument syntax: 351 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] 352 * 353 * - Remove uprobe: -:[GRP/]EVENT 354 */ 355 static int create_trace_uprobe(int argc, char **argv) 356 { 357 struct trace_uprobe *tu; 358 struct inode *inode; 359 char *arg, *event, *group, *filename; 360 char buf[MAX_EVENT_NAME_LEN]; 361 struct path path; 362 unsigned long offset; 363 bool is_delete, is_return; 364 int i, ret; 365 366 inode = NULL; 367 ret = 0; 368 is_delete = false; 369 is_return = false; 370 event = NULL; 371 group = NULL; 372 373 /* argc must be >= 1 */ 374 if (argv[0][0] == '-') 375 is_delete = true; 376 else if (argv[0][0] == 'r') 377 is_return = true; 378 else if (argv[0][0] != 'p') { 379 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n"); 380 return -EINVAL; 381 } 382 383 if (argv[0][1] == ':') { 384 event = &argv[0][2]; 385 arg = strchr(event, '/'); 386 387 if (arg) { 388 group = event; 389 event = arg + 1; 390 event[-1] = '\0'; 391 392 if (strlen(group) == 0) { 393 pr_info("Group name is not specified\n"); 394 return -EINVAL; 395 } 396 } 397 if (strlen(event) == 0) { 398 pr_info("Event name is not specified\n"); 399 return -EINVAL; 400 } 401 } 402 if (!group) 403 group = UPROBE_EVENT_SYSTEM; 404 405 if (is_delete) { 406 int ret; 407 408 if (!event) { 409 pr_info("Delete command needs an event name.\n"); 410 return -EINVAL; 411 } 412 mutex_lock(&uprobe_lock); 413 tu = find_probe_event(event, group); 414 415 if (!tu) { 416 mutex_unlock(&uprobe_lock); 417 pr_info("Event %s/%s doesn't exist.\n", group, event); 418 return -ENOENT; 419 } 420 /* delete an event */ 421 ret = unregister_trace_uprobe(tu); 422 mutex_unlock(&uprobe_lock); 423 return ret; 424 } 425 426 if (argc < 2) { 427 pr_info("Probe point is not specified.\n"); 428 return -EINVAL; 429 } 430 if (isdigit(argv[1][0])) { 431 pr_info("probe point must be have a filename.\n"); 432 return -EINVAL; 433 } 434 arg = strchr(argv[1], ':'); 435 if (!arg) { 436 ret = -EINVAL; 437 goto fail_address_parse; 438 } 439 440 *arg++ = '\0'; 441 filename = argv[1]; 442 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 443 if (ret) 444 goto fail_address_parse; 445 446 inode = igrab(d_inode(path.dentry)); 447 path_put(&path); 448 449 if (!inode || !S_ISREG(inode->i_mode)) { 450 ret = -EINVAL; 451 goto fail_address_parse; 452 } 453 454 ret = kstrtoul(arg, 0, &offset); 455 if (ret) 456 goto fail_address_parse; 457 458 argc -= 2; 459 argv += 2; 460 461 /* setup a probe */ 462 if (!event) { 463 char *tail; 464 char *ptr; 465 466 tail = kstrdup(kbasename(filename), GFP_KERNEL); 467 if (!tail) { 468 ret = -ENOMEM; 469 goto fail_address_parse; 470 } 471 472 ptr = strpbrk(tail, ".-_"); 473 if (ptr) 474 *ptr = '\0'; 475 476 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 477 event = buf; 478 kfree(tail); 479 } 480 481 tu = alloc_trace_uprobe(group, event, argc, is_return); 482 if (IS_ERR(tu)) { 483 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); 484 ret = PTR_ERR(tu); 485 goto fail_address_parse; 486 } 487 tu->offset = offset; 488 tu->inode = inode; 489 tu->filename = kstrdup(filename, GFP_KERNEL); 490 491 if (!tu->filename) { 492 pr_info("Failed to allocate filename.\n"); 493 ret = -ENOMEM; 494 goto error; 495 } 496 497 /* parse arguments */ 498 ret = 0; 499 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 500 struct probe_arg *parg = &tu->tp.args[i]; 501 502 /* Increment count for freeing args in error case */ 503 tu->tp.nr_args++; 504 505 /* Parse argument name */ 506 arg = strchr(argv[i], '='); 507 if (arg) { 508 *arg++ = '\0'; 509 parg->name = kstrdup(argv[i], GFP_KERNEL); 510 } else { 511 arg = argv[i]; 512 /* If argument name is omitted, set "argN" */ 513 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); 514 parg->name = kstrdup(buf, GFP_KERNEL); 515 } 516 517 if (!parg->name) { 518 pr_info("Failed to allocate argument[%d] name.\n", i); 519 ret = -ENOMEM; 520 goto error; 521 } 522 523 if (!is_good_name(parg->name)) { 524 pr_info("Invalid argument[%d] name: %s\n", i, parg->name); 525 ret = -EINVAL; 526 goto error; 527 } 528 529 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) { 530 pr_info("Argument[%d] name '%s' conflicts with " 531 "another field.\n", i, argv[i]); 532 ret = -EINVAL; 533 goto error; 534 } 535 536 /* Parse fetch argument */ 537 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg, 538 is_return, false, 539 uprobes_fetch_type_table); 540 if (ret) { 541 pr_info("Parse error at argument[%d]. (%d)\n", i, ret); 542 goto error; 543 } 544 } 545 546 ret = register_trace_uprobe(tu); 547 if (ret) 548 goto error; 549 return 0; 550 551 error: 552 free_trace_uprobe(tu); 553 return ret; 554 555 fail_address_parse: 556 iput(inode); 557 558 pr_info("Failed to parse address or file.\n"); 559 560 return ret; 561 } 562 563 static int cleanup_all_probes(void) 564 { 565 struct trace_uprobe *tu; 566 int ret = 0; 567 568 mutex_lock(&uprobe_lock); 569 while (!list_empty(&uprobe_list)) { 570 tu = list_entry(uprobe_list.next, struct trace_uprobe, list); 571 ret = unregister_trace_uprobe(tu); 572 if (ret) 573 break; 574 } 575 mutex_unlock(&uprobe_lock); 576 return ret; 577 } 578 579 /* Probes listing interfaces */ 580 static void *probes_seq_start(struct seq_file *m, loff_t *pos) 581 { 582 mutex_lock(&uprobe_lock); 583 return seq_list_start(&uprobe_list, *pos); 584 } 585 586 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) 587 { 588 return seq_list_next(v, &uprobe_list, pos); 589 } 590 591 static void probes_seq_stop(struct seq_file *m, void *v) 592 { 593 mutex_unlock(&uprobe_lock); 594 } 595 596 static int probes_seq_show(struct seq_file *m, void *v) 597 { 598 struct trace_uprobe *tu = v; 599 char c = is_ret_probe(tu) ? 'r' : 'p'; 600 int i; 601 602 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system, 603 trace_event_name(&tu->tp.call)); 604 seq_printf(m, " %s:", tu->filename); 605 606 /* Don't print "0x (null)" when offset is 0 */ 607 if (tu->offset) { 608 seq_printf(m, "0x%p", (void *)tu->offset); 609 } else { 610 switch (sizeof(void *)) { 611 case 4: 612 seq_printf(m, "0x00000000"); 613 break; 614 case 8: 615 default: 616 seq_printf(m, "0x0000000000000000"); 617 break; 618 } 619 } 620 621 for (i = 0; i < tu->tp.nr_args; i++) 622 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 623 624 seq_putc(m, '\n'); 625 return 0; 626 } 627 628 static const struct seq_operations probes_seq_op = { 629 .start = probes_seq_start, 630 .next = probes_seq_next, 631 .stop = probes_seq_stop, 632 .show = probes_seq_show 633 }; 634 635 static int probes_open(struct inode *inode, struct file *file) 636 { 637 int ret; 638 639 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 640 ret = cleanup_all_probes(); 641 if (ret) 642 return ret; 643 } 644 645 return seq_open(file, &probes_seq_op); 646 } 647 648 static ssize_t probes_write(struct file *file, const char __user *buffer, 649 size_t count, loff_t *ppos) 650 { 651 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); 652 } 653 654 static const struct file_operations uprobe_events_ops = { 655 .owner = THIS_MODULE, 656 .open = probes_open, 657 .read = seq_read, 658 .llseek = seq_lseek, 659 .release = seq_release, 660 .write = probes_write, 661 }; 662 663 /* Probes profiling interfaces */ 664 static int probes_profile_seq_show(struct seq_file *m, void *v) 665 { 666 struct trace_uprobe *tu = v; 667 668 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 669 trace_event_name(&tu->tp.call), tu->nhit); 670 return 0; 671 } 672 673 static const struct seq_operations profile_seq_op = { 674 .start = probes_seq_start, 675 .next = probes_seq_next, 676 .stop = probes_seq_stop, 677 .show = probes_profile_seq_show 678 }; 679 680 static int profile_open(struct inode *inode, struct file *file) 681 { 682 return seq_open(file, &profile_seq_op); 683 } 684 685 static const struct file_operations uprobe_profile_ops = { 686 .owner = THIS_MODULE, 687 .open = profile_open, 688 .read = seq_read, 689 .llseek = seq_lseek, 690 .release = seq_release, 691 }; 692 693 struct uprobe_cpu_buffer { 694 struct mutex mutex; 695 void *buf; 696 }; 697 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 698 static int uprobe_buffer_refcnt; 699 700 static int uprobe_buffer_init(void) 701 { 702 int cpu, err_cpu; 703 704 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 705 if (uprobe_cpu_buffer == NULL) 706 return -ENOMEM; 707 708 for_each_possible_cpu(cpu) { 709 struct page *p = alloc_pages_node(cpu_to_node(cpu), 710 GFP_KERNEL, 0); 711 if (p == NULL) { 712 err_cpu = cpu; 713 goto err; 714 } 715 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 716 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 717 } 718 719 return 0; 720 721 err: 722 for_each_possible_cpu(cpu) { 723 if (cpu == err_cpu) 724 break; 725 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 726 } 727 728 free_percpu(uprobe_cpu_buffer); 729 return -ENOMEM; 730 } 731 732 static int uprobe_buffer_enable(void) 733 { 734 int ret = 0; 735 736 BUG_ON(!mutex_is_locked(&event_mutex)); 737 738 if (uprobe_buffer_refcnt++ == 0) { 739 ret = uprobe_buffer_init(); 740 if (ret < 0) 741 uprobe_buffer_refcnt--; 742 } 743 744 return ret; 745 } 746 747 static void uprobe_buffer_disable(void) 748 { 749 int cpu; 750 751 BUG_ON(!mutex_is_locked(&event_mutex)); 752 753 if (--uprobe_buffer_refcnt == 0) { 754 for_each_possible_cpu(cpu) 755 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 756 cpu)->buf); 757 758 free_percpu(uprobe_cpu_buffer); 759 uprobe_cpu_buffer = NULL; 760 } 761 } 762 763 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 764 { 765 struct uprobe_cpu_buffer *ucb; 766 int cpu; 767 768 cpu = raw_smp_processor_id(); 769 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 770 771 /* 772 * Use per-cpu buffers for fastest access, but we might migrate 773 * so the mutex makes sure we have sole access to it. 774 */ 775 mutex_lock(&ucb->mutex); 776 777 return ucb; 778 } 779 780 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 781 { 782 mutex_unlock(&ucb->mutex); 783 } 784 785 static void __uprobe_trace_func(struct trace_uprobe *tu, 786 unsigned long func, struct pt_regs *regs, 787 struct uprobe_cpu_buffer *ucb, int dsize, 788 struct trace_event_file *trace_file) 789 { 790 struct uprobe_trace_entry_head *entry; 791 struct ring_buffer_event *event; 792 struct ring_buffer *buffer; 793 void *data; 794 int size, esize; 795 struct trace_event_call *call = &tu->tp.call; 796 797 WARN_ON(call != trace_file->event_call); 798 799 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 800 return; 801 802 if (trace_trigger_soft_disabled(trace_file)) 803 return; 804 805 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 806 size = esize + tu->tp.size + dsize; 807 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 808 call->event.type, size, 0, 0); 809 if (!event) 810 return; 811 812 entry = ring_buffer_event_data(event); 813 if (is_ret_probe(tu)) { 814 entry->vaddr[0] = func; 815 entry->vaddr[1] = instruction_pointer(regs); 816 data = DATAOF_TRACE_ENTRY(entry, true); 817 } else { 818 entry->vaddr[0] = instruction_pointer(regs); 819 data = DATAOF_TRACE_ENTRY(entry, false); 820 } 821 822 memcpy(data, ucb->buf, tu->tp.size + dsize); 823 824 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); 825 } 826 827 /* uprobe handler */ 828 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 829 struct uprobe_cpu_buffer *ucb, int dsize) 830 { 831 struct event_file_link *link; 832 833 if (is_ret_probe(tu)) 834 return 0; 835 836 rcu_read_lock(); 837 list_for_each_entry_rcu(link, &tu->tp.files, list) 838 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 839 rcu_read_unlock(); 840 841 return 0; 842 } 843 844 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 845 struct pt_regs *regs, 846 struct uprobe_cpu_buffer *ucb, int dsize) 847 { 848 struct event_file_link *link; 849 850 rcu_read_lock(); 851 list_for_each_entry_rcu(link, &tu->tp.files, list) 852 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 853 rcu_read_unlock(); 854 } 855 856 /* Event entry printers */ 857 static enum print_line_t 858 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 859 { 860 struct uprobe_trace_entry_head *entry; 861 struct trace_seq *s = &iter->seq; 862 struct trace_uprobe *tu; 863 u8 *data; 864 int i; 865 866 entry = (struct uprobe_trace_entry_head *)iter->ent; 867 tu = container_of(event, struct trace_uprobe, tp.call.event); 868 869 if (is_ret_probe(tu)) { 870 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 871 trace_event_name(&tu->tp.call), 872 entry->vaddr[1], entry->vaddr[0]); 873 data = DATAOF_TRACE_ENTRY(entry, true); 874 } else { 875 trace_seq_printf(s, "%s: (0x%lx)", 876 trace_event_name(&tu->tp.call), 877 entry->vaddr[0]); 878 data = DATAOF_TRACE_ENTRY(entry, false); 879 } 880 881 for (i = 0; i < tu->tp.nr_args; i++) { 882 struct probe_arg *parg = &tu->tp.args[i]; 883 884 if (!parg->type->print(s, parg->name, data + parg->offset, entry)) 885 goto out; 886 } 887 888 trace_seq_putc(s, '\n'); 889 890 out: 891 return trace_handle_return(s); 892 } 893 894 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 895 enum uprobe_filter_ctx ctx, 896 struct mm_struct *mm); 897 898 static int 899 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, 900 filter_func_t filter) 901 { 902 bool enabled = trace_probe_is_enabled(&tu->tp); 903 struct event_file_link *link = NULL; 904 int ret; 905 906 if (file) { 907 if (tu->tp.flags & TP_FLAG_PROFILE) 908 return -EINTR; 909 910 link = kmalloc(sizeof(*link), GFP_KERNEL); 911 if (!link) 912 return -ENOMEM; 913 914 link->file = file; 915 list_add_tail_rcu(&link->list, &tu->tp.files); 916 917 tu->tp.flags |= TP_FLAG_TRACE; 918 } else { 919 if (tu->tp.flags & TP_FLAG_TRACE) 920 return -EINTR; 921 922 tu->tp.flags |= TP_FLAG_PROFILE; 923 } 924 925 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 926 927 if (enabled) 928 return 0; 929 930 ret = uprobe_buffer_enable(); 931 if (ret) 932 goto err_flags; 933 934 tu->consumer.filter = filter; 935 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 936 if (ret) 937 goto err_buffer; 938 939 return 0; 940 941 err_buffer: 942 uprobe_buffer_disable(); 943 944 err_flags: 945 if (file) { 946 list_del(&link->list); 947 kfree(link); 948 tu->tp.flags &= ~TP_FLAG_TRACE; 949 } else { 950 tu->tp.flags &= ~TP_FLAG_PROFILE; 951 } 952 return ret; 953 } 954 955 static void 956 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) 957 { 958 if (!trace_probe_is_enabled(&tu->tp)) 959 return; 960 961 if (file) { 962 struct event_file_link *link; 963 964 link = find_event_file_link(&tu->tp, file); 965 if (!link) 966 return; 967 968 list_del_rcu(&link->list); 969 /* synchronize with u{,ret}probe_trace_func */ 970 synchronize_sched(); 971 kfree(link); 972 973 if (!list_empty(&tu->tp.files)) 974 return; 975 } 976 977 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 978 979 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 980 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 981 982 uprobe_buffer_disable(); 983 } 984 985 static int uprobe_event_define_fields(struct trace_event_call *event_call) 986 { 987 int ret, i, size; 988 struct uprobe_trace_entry_head field; 989 struct trace_uprobe *tu = event_call->data; 990 991 if (is_ret_probe(tu)) { 992 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 993 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 994 size = SIZEOF_TRACE_ENTRY(true); 995 } else { 996 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 997 size = SIZEOF_TRACE_ENTRY(false); 998 } 999 /* Set argument names as fields */ 1000 for (i = 0; i < tu->tp.nr_args; i++) { 1001 struct probe_arg *parg = &tu->tp.args[i]; 1002 1003 ret = trace_define_field(event_call, parg->type->fmttype, 1004 parg->name, size + parg->offset, 1005 parg->type->size, parg->type->is_signed, 1006 FILTER_OTHER); 1007 1008 if (ret) 1009 return ret; 1010 } 1011 return 0; 1012 } 1013 1014 #ifdef CONFIG_PERF_EVENTS 1015 static bool 1016 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1017 { 1018 struct perf_event *event; 1019 1020 if (filter->nr_systemwide) 1021 return true; 1022 1023 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1024 if (event->hw.target->mm == mm) 1025 return true; 1026 } 1027 1028 return false; 1029 } 1030 1031 static inline bool 1032 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1033 { 1034 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1035 } 1036 1037 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1038 { 1039 bool done; 1040 1041 write_lock(&tu->filter.rwlock); 1042 if (event->hw.target) { 1043 list_del(&event->hw.tp_list); 1044 done = tu->filter.nr_systemwide || 1045 (event->hw.target->flags & PF_EXITING) || 1046 uprobe_filter_event(tu, event); 1047 } else { 1048 tu->filter.nr_systemwide--; 1049 done = tu->filter.nr_systemwide; 1050 } 1051 write_unlock(&tu->filter.rwlock); 1052 1053 if (!done) 1054 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1055 1056 return 0; 1057 } 1058 1059 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1060 { 1061 bool done; 1062 int err; 1063 1064 write_lock(&tu->filter.rwlock); 1065 if (event->hw.target) { 1066 /* 1067 * event->parent != NULL means copy_process(), we can avoid 1068 * uprobe_apply(). current->mm must be probed and we can rely 1069 * on dup_mmap() which preserves the already installed bp's. 1070 * 1071 * attr.enable_on_exec means that exec/mmap will install the 1072 * breakpoints we need. 1073 */ 1074 done = tu->filter.nr_systemwide || 1075 event->parent || event->attr.enable_on_exec || 1076 uprobe_filter_event(tu, event); 1077 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1078 } else { 1079 done = tu->filter.nr_systemwide; 1080 tu->filter.nr_systemwide++; 1081 } 1082 write_unlock(&tu->filter.rwlock); 1083 1084 err = 0; 1085 if (!done) { 1086 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1087 if (err) 1088 uprobe_perf_close(tu, event); 1089 } 1090 return err; 1091 } 1092 1093 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1094 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1095 { 1096 struct trace_uprobe *tu; 1097 int ret; 1098 1099 tu = container_of(uc, struct trace_uprobe, consumer); 1100 read_lock(&tu->filter.rwlock); 1101 ret = __uprobe_perf_filter(&tu->filter, mm); 1102 read_unlock(&tu->filter.rwlock); 1103 1104 return ret; 1105 } 1106 1107 static void __uprobe_perf_func(struct trace_uprobe *tu, 1108 unsigned long func, struct pt_regs *regs, 1109 struct uprobe_cpu_buffer *ucb, int dsize) 1110 { 1111 struct trace_event_call *call = &tu->tp.call; 1112 struct uprobe_trace_entry_head *entry; 1113 struct bpf_prog *prog = call->prog; 1114 struct hlist_head *head; 1115 void *data; 1116 int size, esize; 1117 int rctx; 1118 1119 if (prog && !trace_call_bpf(prog, regs)) 1120 return; 1121 1122 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1123 1124 size = esize + tu->tp.size + dsize; 1125 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1126 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1127 return; 1128 1129 preempt_disable(); 1130 head = this_cpu_ptr(call->perf_events); 1131 if (hlist_empty(head)) 1132 goto out; 1133 1134 entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx); 1135 if (!entry) 1136 goto out; 1137 1138 if (is_ret_probe(tu)) { 1139 entry->vaddr[0] = func; 1140 entry->vaddr[1] = instruction_pointer(regs); 1141 data = DATAOF_TRACE_ENTRY(entry, true); 1142 } else { 1143 entry->vaddr[0] = instruction_pointer(regs); 1144 data = DATAOF_TRACE_ENTRY(entry, false); 1145 } 1146 1147 memcpy(data, ucb->buf, tu->tp.size + dsize); 1148 1149 if (size - esize > tu->tp.size + dsize) { 1150 int len = tu->tp.size + dsize; 1151 1152 memset(data + len, 0, size - esize - len); 1153 } 1154 1155 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL); 1156 out: 1157 preempt_enable(); 1158 } 1159 1160 /* uprobe profile handler */ 1161 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1162 struct uprobe_cpu_buffer *ucb, int dsize) 1163 { 1164 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1165 return UPROBE_HANDLER_REMOVE; 1166 1167 if (!is_ret_probe(tu)) 1168 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1169 return 0; 1170 } 1171 1172 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1173 struct pt_regs *regs, 1174 struct uprobe_cpu_buffer *ucb, int dsize) 1175 { 1176 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1177 } 1178 #endif /* CONFIG_PERF_EVENTS */ 1179 1180 static int 1181 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, 1182 void *data) 1183 { 1184 struct trace_uprobe *tu = event->data; 1185 struct trace_event_file *file = data; 1186 1187 switch (type) { 1188 case TRACE_REG_REGISTER: 1189 return probe_event_enable(tu, file, NULL); 1190 1191 case TRACE_REG_UNREGISTER: 1192 probe_event_disable(tu, file); 1193 return 0; 1194 1195 #ifdef CONFIG_PERF_EVENTS 1196 case TRACE_REG_PERF_REGISTER: 1197 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1198 1199 case TRACE_REG_PERF_UNREGISTER: 1200 probe_event_disable(tu, NULL); 1201 return 0; 1202 1203 case TRACE_REG_PERF_OPEN: 1204 return uprobe_perf_open(tu, data); 1205 1206 case TRACE_REG_PERF_CLOSE: 1207 return uprobe_perf_close(tu, data); 1208 1209 #endif 1210 default: 1211 return 0; 1212 } 1213 return 0; 1214 } 1215 1216 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1217 { 1218 struct trace_uprobe *tu; 1219 struct uprobe_dispatch_data udd; 1220 struct uprobe_cpu_buffer *ucb; 1221 int dsize, esize; 1222 int ret = 0; 1223 1224 1225 tu = container_of(con, struct trace_uprobe, consumer); 1226 tu->nhit++; 1227 1228 udd.tu = tu; 1229 udd.bp_addr = instruction_pointer(regs); 1230 1231 current->utask->vaddr = (unsigned long) &udd; 1232 1233 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1234 return 0; 1235 1236 dsize = __get_data_size(&tu->tp, regs); 1237 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1238 1239 ucb = uprobe_buffer_get(); 1240 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1241 1242 if (tu->tp.flags & TP_FLAG_TRACE) 1243 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1244 1245 #ifdef CONFIG_PERF_EVENTS 1246 if (tu->tp.flags & TP_FLAG_PROFILE) 1247 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1248 #endif 1249 uprobe_buffer_put(ucb); 1250 return ret; 1251 } 1252 1253 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1254 unsigned long func, struct pt_regs *regs) 1255 { 1256 struct trace_uprobe *tu; 1257 struct uprobe_dispatch_data udd; 1258 struct uprobe_cpu_buffer *ucb; 1259 int dsize, esize; 1260 1261 tu = container_of(con, struct trace_uprobe, consumer); 1262 1263 udd.tu = tu; 1264 udd.bp_addr = func; 1265 1266 current->utask->vaddr = (unsigned long) &udd; 1267 1268 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1269 return 0; 1270 1271 dsize = __get_data_size(&tu->tp, regs); 1272 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1273 1274 ucb = uprobe_buffer_get(); 1275 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1276 1277 if (tu->tp.flags & TP_FLAG_TRACE) 1278 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1279 1280 #ifdef CONFIG_PERF_EVENTS 1281 if (tu->tp.flags & TP_FLAG_PROFILE) 1282 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1283 #endif 1284 uprobe_buffer_put(ucb); 1285 return 0; 1286 } 1287 1288 static struct trace_event_functions uprobe_funcs = { 1289 .trace = print_uprobe_event 1290 }; 1291 1292 static int register_uprobe_event(struct trace_uprobe *tu) 1293 { 1294 struct trace_event_call *call = &tu->tp.call; 1295 int ret; 1296 1297 /* Initialize trace_event_call */ 1298 INIT_LIST_HEAD(&call->class->fields); 1299 call->event.funcs = &uprobe_funcs; 1300 call->class->define_fields = uprobe_event_define_fields; 1301 1302 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1303 return -ENOMEM; 1304 1305 ret = register_trace_event(&call->event); 1306 if (!ret) { 1307 kfree(call->print_fmt); 1308 return -ENODEV; 1309 } 1310 1311 call->flags = TRACE_EVENT_FL_UPROBE; 1312 call->class->reg = trace_uprobe_register; 1313 call->data = tu; 1314 ret = trace_add_event_call(call); 1315 1316 if (ret) { 1317 pr_info("Failed to register uprobe event: %s\n", 1318 trace_event_name(call)); 1319 kfree(call->print_fmt); 1320 unregister_trace_event(&call->event); 1321 } 1322 1323 return ret; 1324 } 1325 1326 static int unregister_uprobe_event(struct trace_uprobe *tu) 1327 { 1328 int ret; 1329 1330 /* tu->event is unregistered in trace_remove_event_call() */ 1331 ret = trace_remove_event_call(&tu->tp.call); 1332 if (ret) 1333 return ret; 1334 kfree(tu->tp.call.print_fmt); 1335 tu->tp.call.print_fmt = NULL; 1336 return 0; 1337 } 1338 1339 /* Make a trace interface for controling probe points */ 1340 static __init int init_uprobe_trace(void) 1341 { 1342 struct dentry *d_tracer; 1343 1344 d_tracer = tracing_init_dentry(); 1345 if (IS_ERR(d_tracer)) 1346 return 0; 1347 1348 trace_create_file("uprobe_events", 0644, d_tracer, 1349 NULL, &uprobe_events_ops); 1350 /* Profile interface */ 1351 trace_create_file("uprobe_profile", 0444, d_tracer, 1352 NULL, &uprobe_profile_ops); 1353 return 0; 1354 } 1355 1356 fs_initcall(init_uprobe_trace); 1357