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 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0), 215 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), 216 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), 217 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), 218 219 ASSIGN_FETCH_TYPE_END 220 }; 221 222 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) 223 { 224 rwlock_init(&filter->rwlock); 225 filter->nr_systemwide = 0; 226 INIT_LIST_HEAD(&filter->perf_events); 227 } 228 229 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 230 { 231 return !filter->nr_systemwide && list_empty(&filter->perf_events); 232 } 233 234 static inline bool is_ret_probe(struct trace_uprobe *tu) 235 { 236 return tu->consumer.ret_handler != NULL; 237 } 238 239 /* 240 * Allocate new trace_uprobe and initialize it (including uprobes). 241 */ 242 static struct trace_uprobe * 243 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 244 { 245 struct trace_uprobe *tu; 246 247 if (!event || !is_good_name(event)) 248 return ERR_PTR(-EINVAL); 249 250 if (!group || !is_good_name(group)) 251 return ERR_PTR(-EINVAL); 252 253 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); 254 if (!tu) 255 return ERR_PTR(-ENOMEM); 256 257 tu->tp.call.class = &tu->tp.class; 258 tu->tp.call.name = kstrdup(event, GFP_KERNEL); 259 if (!tu->tp.call.name) 260 goto error; 261 262 tu->tp.class.system = kstrdup(group, GFP_KERNEL); 263 if (!tu->tp.class.system) 264 goto error; 265 266 INIT_LIST_HEAD(&tu->list); 267 INIT_LIST_HEAD(&tu->tp.files); 268 tu->consumer.handler = uprobe_dispatcher; 269 if (is_ret) 270 tu->consumer.ret_handler = uretprobe_dispatcher; 271 init_trace_uprobe_filter(&tu->filter); 272 return tu; 273 274 error: 275 kfree(tu->tp.call.name); 276 kfree(tu); 277 278 return ERR_PTR(-ENOMEM); 279 } 280 281 static void free_trace_uprobe(struct trace_uprobe *tu) 282 { 283 int i; 284 285 for (i = 0; i < tu->tp.nr_args; i++) 286 traceprobe_free_probe_arg(&tu->tp.args[i]); 287 288 iput(tu->inode); 289 kfree(tu->tp.call.class->system); 290 kfree(tu->tp.call.name); 291 kfree(tu->filename); 292 kfree(tu); 293 } 294 295 static struct trace_uprobe *find_probe_event(const char *event, const char *group) 296 { 297 struct trace_uprobe *tu; 298 299 list_for_each_entry(tu, &uprobe_list, list) 300 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 && 301 strcmp(tu->tp.call.class->system, group) == 0) 302 return tu; 303 304 return NULL; 305 } 306 307 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ 308 static int unregister_trace_uprobe(struct trace_uprobe *tu) 309 { 310 int ret; 311 312 ret = unregister_uprobe_event(tu); 313 if (ret) 314 return ret; 315 316 list_del(&tu->list); 317 free_trace_uprobe(tu); 318 return 0; 319 } 320 321 /* Register a trace_uprobe and probe_event */ 322 static int register_trace_uprobe(struct trace_uprobe *tu) 323 { 324 struct trace_uprobe *old_tu; 325 int ret; 326 327 mutex_lock(&uprobe_lock); 328 329 /* register as an event */ 330 old_tu = find_probe_event(trace_event_name(&tu->tp.call), 331 tu->tp.call.class->system); 332 if (old_tu) { 333 /* delete old event */ 334 ret = unregister_trace_uprobe(old_tu); 335 if (ret) 336 goto end; 337 } 338 339 ret = register_uprobe_event(tu); 340 if (ret) { 341 pr_warn("Failed to register probe event(%d)\n", ret); 342 goto end; 343 } 344 345 list_add_tail(&tu->list, &uprobe_list); 346 347 end: 348 mutex_unlock(&uprobe_lock); 349 350 return ret; 351 } 352 353 /* 354 * Argument syntax: 355 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] 356 * 357 * - Remove uprobe: -:[GRP/]EVENT 358 */ 359 static int create_trace_uprobe(int argc, char **argv) 360 { 361 struct trace_uprobe *tu; 362 struct inode *inode; 363 char *arg, *event, *group, *filename; 364 char buf[MAX_EVENT_NAME_LEN]; 365 struct path path; 366 unsigned long offset; 367 bool is_delete, is_return; 368 int i, ret; 369 370 inode = NULL; 371 ret = 0; 372 is_delete = false; 373 is_return = false; 374 event = NULL; 375 group = NULL; 376 377 /* argc must be >= 1 */ 378 if (argv[0][0] == '-') 379 is_delete = true; 380 else if (argv[0][0] == 'r') 381 is_return = true; 382 else if (argv[0][0] != 'p') { 383 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n"); 384 return -EINVAL; 385 } 386 387 if (argv[0][1] == ':') { 388 event = &argv[0][2]; 389 arg = strchr(event, '/'); 390 391 if (arg) { 392 group = event; 393 event = arg + 1; 394 event[-1] = '\0'; 395 396 if (strlen(group) == 0) { 397 pr_info("Group name is not specified\n"); 398 return -EINVAL; 399 } 400 } 401 if (strlen(event) == 0) { 402 pr_info("Event name is not specified\n"); 403 return -EINVAL; 404 } 405 } 406 if (!group) 407 group = UPROBE_EVENT_SYSTEM; 408 409 if (is_delete) { 410 int ret; 411 412 if (!event) { 413 pr_info("Delete command needs an event name.\n"); 414 return -EINVAL; 415 } 416 mutex_lock(&uprobe_lock); 417 tu = find_probe_event(event, group); 418 419 if (!tu) { 420 mutex_unlock(&uprobe_lock); 421 pr_info("Event %s/%s doesn't exist.\n", group, event); 422 return -ENOENT; 423 } 424 /* delete an event */ 425 ret = unregister_trace_uprobe(tu); 426 mutex_unlock(&uprobe_lock); 427 return ret; 428 } 429 430 if (argc < 2) { 431 pr_info("Probe point is not specified.\n"); 432 return -EINVAL; 433 } 434 if (isdigit(argv[1][0])) { 435 pr_info("probe point must be have a filename.\n"); 436 return -EINVAL; 437 } 438 arg = strchr(argv[1], ':'); 439 if (!arg) { 440 ret = -EINVAL; 441 goto fail_address_parse; 442 } 443 444 *arg++ = '\0'; 445 filename = argv[1]; 446 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 447 if (ret) 448 goto fail_address_parse; 449 450 inode = igrab(d_inode(path.dentry)); 451 path_put(&path); 452 453 if (!inode || !S_ISREG(inode->i_mode)) { 454 ret = -EINVAL; 455 goto fail_address_parse; 456 } 457 458 ret = kstrtoul(arg, 0, &offset); 459 if (ret) 460 goto fail_address_parse; 461 462 argc -= 2; 463 argv += 2; 464 465 /* setup a probe */ 466 if (!event) { 467 char *tail; 468 char *ptr; 469 470 tail = kstrdup(kbasename(filename), GFP_KERNEL); 471 if (!tail) { 472 ret = -ENOMEM; 473 goto fail_address_parse; 474 } 475 476 ptr = strpbrk(tail, ".-_"); 477 if (ptr) 478 *ptr = '\0'; 479 480 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 481 event = buf; 482 kfree(tail); 483 } 484 485 tu = alloc_trace_uprobe(group, event, argc, is_return); 486 if (IS_ERR(tu)) { 487 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); 488 ret = PTR_ERR(tu); 489 goto fail_address_parse; 490 } 491 tu->offset = offset; 492 tu->inode = inode; 493 tu->filename = kstrdup(filename, GFP_KERNEL); 494 495 if (!tu->filename) { 496 pr_info("Failed to allocate filename.\n"); 497 ret = -ENOMEM; 498 goto error; 499 } 500 501 /* parse arguments */ 502 ret = 0; 503 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 504 struct probe_arg *parg = &tu->tp.args[i]; 505 506 /* Increment count for freeing args in error case */ 507 tu->tp.nr_args++; 508 509 /* Parse argument name */ 510 arg = strchr(argv[i], '='); 511 if (arg) { 512 *arg++ = '\0'; 513 parg->name = kstrdup(argv[i], GFP_KERNEL); 514 } else { 515 arg = argv[i]; 516 /* If argument name is omitted, set "argN" */ 517 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); 518 parg->name = kstrdup(buf, GFP_KERNEL); 519 } 520 521 if (!parg->name) { 522 pr_info("Failed to allocate argument[%d] name.\n", i); 523 ret = -ENOMEM; 524 goto error; 525 } 526 527 if (!is_good_name(parg->name)) { 528 pr_info("Invalid argument[%d] name: %s\n", i, parg->name); 529 ret = -EINVAL; 530 goto error; 531 } 532 533 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) { 534 pr_info("Argument[%d] name '%s' conflicts with " 535 "another field.\n", i, argv[i]); 536 ret = -EINVAL; 537 goto error; 538 } 539 540 /* Parse fetch argument */ 541 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg, 542 is_return, false, 543 uprobes_fetch_type_table); 544 if (ret) { 545 pr_info("Parse error at argument[%d]. (%d)\n", i, ret); 546 goto error; 547 } 548 } 549 550 ret = register_trace_uprobe(tu); 551 if (ret) 552 goto error; 553 return 0; 554 555 error: 556 free_trace_uprobe(tu); 557 return ret; 558 559 fail_address_parse: 560 iput(inode); 561 562 pr_info("Failed to parse address or file.\n"); 563 564 return ret; 565 } 566 567 static int cleanup_all_probes(void) 568 { 569 struct trace_uprobe *tu; 570 int ret = 0; 571 572 mutex_lock(&uprobe_lock); 573 while (!list_empty(&uprobe_list)) { 574 tu = list_entry(uprobe_list.next, struct trace_uprobe, list); 575 ret = unregister_trace_uprobe(tu); 576 if (ret) 577 break; 578 } 579 mutex_unlock(&uprobe_lock); 580 return ret; 581 } 582 583 /* Probes listing interfaces */ 584 static void *probes_seq_start(struct seq_file *m, loff_t *pos) 585 { 586 mutex_lock(&uprobe_lock); 587 return seq_list_start(&uprobe_list, *pos); 588 } 589 590 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) 591 { 592 return seq_list_next(v, &uprobe_list, pos); 593 } 594 595 static void probes_seq_stop(struct seq_file *m, void *v) 596 { 597 mutex_unlock(&uprobe_lock); 598 } 599 600 static int probes_seq_show(struct seq_file *m, void *v) 601 { 602 struct trace_uprobe *tu = v; 603 char c = is_ret_probe(tu) ? 'r' : 'p'; 604 int i; 605 606 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system, 607 trace_event_name(&tu->tp.call)); 608 seq_printf(m, " %s:", tu->filename); 609 610 /* Don't print "0x (null)" when offset is 0 */ 611 if (tu->offset) { 612 seq_printf(m, "0x%p", (void *)tu->offset); 613 } else { 614 switch (sizeof(void *)) { 615 case 4: 616 seq_printf(m, "0x00000000"); 617 break; 618 case 8: 619 default: 620 seq_printf(m, "0x0000000000000000"); 621 break; 622 } 623 } 624 625 for (i = 0; i < tu->tp.nr_args; i++) 626 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 627 628 seq_putc(m, '\n'); 629 return 0; 630 } 631 632 static const struct seq_operations probes_seq_op = { 633 .start = probes_seq_start, 634 .next = probes_seq_next, 635 .stop = probes_seq_stop, 636 .show = probes_seq_show 637 }; 638 639 static int probes_open(struct inode *inode, struct file *file) 640 { 641 int ret; 642 643 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 644 ret = cleanup_all_probes(); 645 if (ret) 646 return ret; 647 } 648 649 return seq_open(file, &probes_seq_op); 650 } 651 652 static ssize_t probes_write(struct file *file, const char __user *buffer, 653 size_t count, loff_t *ppos) 654 { 655 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); 656 } 657 658 static const struct file_operations uprobe_events_ops = { 659 .owner = THIS_MODULE, 660 .open = probes_open, 661 .read = seq_read, 662 .llseek = seq_lseek, 663 .release = seq_release, 664 .write = probes_write, 665 }; 666 667 /* Probes profiling interfaces */ 668 static int probes_profile_seq_show(struct seq_file *m, void *v) 669 { 670 struct trace_uprobe *tu = v; 671 672 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 673 trace_event_name(&tu->tp.call), tu->nhit); 674 return 0; 675 } 676 677 static const struct seq_operations profile_seq_op = { 678 .start = probes_seq_start, 679 .next = probes_seq_next, 680 .stop = probes_seq_stop, 681 .show = probes_profile_seq_show 682 }; 683 684 static int profile_open(struct inode *inode, struct file *file) 685 { 686 return seq_open(file, &profile_seq_op); 687 } 688 689 static const struct file_operations uprobe_profile_ops = { 690 .owner = THIS_MODULE, 691 .open = profile_open, 692 .read = seq_read, 693 .llseek = seq_lseek, 694 .release = seq_release, 695 }; 696 697 struct uprobe_cpu_buffer { 698 struct mutex mutex; 699 void *buf; 700 }; 701 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 702 static int uprobe_buffer_refcnt; 703 704 static int uprobe_buffer_init(void) 705 { 706 int cpu, err_cpu; 707 708 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 709 if (uprobe_cpu_buffer == NULL) 710 return -ENOMEM; 711 712 for_each_possible_cpu(cpu) { 713 struct page *p = alloc_pages_node(cpu_to_node(cpu), 714 GFP_KERNEL, 0); 715 if (p == NULL) { 716 err_cpu = cpu; 717 goto err; 718 } 719 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 720 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 721 } 722 723 return 0; 724 725 err: 726 for_each_possible_cpu(cpu) { 727 if (cpu == err_cpu) 728 break; 729 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 730 } 731 732 free_percpu(uprobe_cpu_buffer); 733 return -ENOMEM; 734 } 735 736 static int uprobe_buffer_enable(void) 737 { 738 int ret = 0; 739 740 BUG_ON(!mutex_is_locked(&event_mutex)); 741 742 if (uprobe_buffer_refcnt++ == 0) { 743 ret = uprobe_buffer_init(); 744 if (ret < 0) 745 uprobe_buffer_refcnt--; 746 } 747 748 return ret; 749 } 750 751 static void uprobe_buffer_disable(void) 752 { 753 int cpu; 754 755 BUG_ON(!mutex_is_locked(&event_mutex)); 756 757 if (--uprobe_buffer_refcnt == 0) { 758 for_each_possible_cpu(cpu) 759 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 760 cpu)->buf); 761 762 free_percpu(uprobe_cpu_buffer); 763 uprobe_cpu_buffer = NULL; 764 } 765 } 766 767 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 768 { 769 struct uprobe_cpu_buffer *ucb; 770 int cpu; 771 772 cpu = raw_smp_processor_id(); 773 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 774 775 /* 776 * Use per-cpu buffers for fastest access, but we might migrate 777 * so the mutex makes sure we have sole access to it. 778 */ 779 mutex_lock(&ucb->mutex); 780 781 return ucb; 782 } 783 784 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 785 { 786 mutex_unlock(&ucb->mutex); 787 } 788 789 static void __uprobe_trace_func(struct trace_uprobe *tu, 790 unsigned long func, struct pt_regs *regs, 791 struct uprobe_cpu_buffer *ucb, int dsize, 792 struct trace_event_file *trace_file) 793 { 794 struct uprobe_trace_entry_head *entry; 795 struct ring_buffer_event *event; 796 struct ring_buffer *buffer; 797 void *data; 798 int size, esize; 799 struct trace_event_call *call = &tu->tp.call; 800 801 WARN_ON(call != trace_file->event_call); 802 803 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 804 return; 805 806 if (trace_trigger_soft_disabled(trace_file)) 807 return; 808 809 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 810 size = esize + tu->tp.size + dsize; 811 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 812 call->event.type, size, 0, 0); 813 if (!event) 814 return; 815 816 entry = ring_buffer_event_data(event); 817 if (is_ret_probe(tu)) { 818 entry->vaddr[0] = func; 819 entry->vaddr[1] = instruction_pointer(regs); 820 data = DATAOF_TRACE_ENTRY(entry, true); 821 } else { 822 entry->vaddr[0] = instruction_pointer(regs); 823 data = DATAOF_TRACE_ENTRY(entry, false); 824 } 825 826 memcpy(data, ucb->buf, tu->tp.size + dsize); 827 828 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); 829 } 830 831 /* uprobe handler */ 832 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 833 struct uprobe_cpu_buffer *ucb, int dsize) 834 { 835 struct event_file_link *link; 836 837 if (is_ret_probe(tu)) 838 return 0; 839 840 rcu_read_lock(); 841 list_for_each_entry_rcu(link, &tu->tp.files, list) 842 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 843 rcu_read_unlock(); 844 845 return 0; 846 } 847 848 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 849 struct pt_regs *regs, 850 struct uprobe_cpu_buffer *ucb, int dsize) 851 { 852 struct event_file_link *link; 853 854 rcu_read_lock(); 855 list_for_each_entry_rcu(link, &tu->tp.files, list) 856 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 857 rcu_read_unlock(); 858 } 859 860 /* Event entry printers */ 861 static enum print_line_t 862 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 863 { 864 struct uprobe_trace_entry_head *entry; 865 struct trace_seq *s = &iter->seq; 866 struct trace_uprobe *tu; 867 u8 *data; 868 int i; 869 870 entry = (struct uprobe_trace_entry_head *)iter->ent; 871 tu = container_of(event, struct trace_uprobe, tp.call.event); 872 873 if (is_ret_probe(tu)) { 874 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 875 trace_event_name(&tu->tp.call), 876 entry->vaddr[1], entry->vaddr[0]); 877 data = DATAOF_TRACE_ENTRY(entry, true); 878 } else { 879 trace_seq_printf(s, "%s: (0x%lx)", 880 trace_event_name(&tu->tp.call), 881 entry->vaddr[0]); 882 data = DATAOF_TRACE_ENTRY(entry, false); 883 } 884 885 for (i = 0; i < tu->tp.nr_args; i++) { 886 struct probe_arg *parg = &tu->tp.args[i]; 887 888 if (!parg->type->print(s, parg->name, data + parg->offset, entry)) 889 goto out; 890 } 891 892 trace_seq_putc(s, '\n'); 893 894 out: 895 return trace_handle_return(s); 896 } 897 898 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 899 enum uprobe_filter_ctx ctx, 900 struct mm_struct *mm); 901 902 static int 903 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, 904 filter_func_t filter) 905 { 906 bool enabled = trace_probe_is_enabled(&tu->tp); 907 struct event_file_link *link = NULL; 908 int ret; 909 910 if (file) { 911 if (tu->tp.flags & TP_FLAG_PROFILE) 912 return -EINTR; 913 914 link = kmalloc(sizeof(*link), GFP_KERNEL); 915 if (!link) 916 return -ENOMEM; 917 918 link->file = file; 919 list_add_tail_rcu(&link->list, &tu->tp.files); 920 921 tu->tp.flags |= TP_FLAG_TRACE; 922 } else { 923 if (tu->tp.flags & TP_FLAG_TRACE) 924 return -EINTR; 925 926 tu->tp.flags |= TP_FLAG_PROFILE; 927 } 928 929 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 930 931 if (enabled) 932 return 0; 933 934 ret = uprobe_buffer_enable(); 935 if (ret) 936 goto err_flags; 937 938 tu->consumer.filter = filter; 939 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 940 if (ret) 941 goto err_buffer; 942 943 return 0; 944 945 err_buffer: 946 uprobe_buffer_disable(); 947 948 err_flags: 949 if (file) { 950 list_del(&link->list); 951 kfree(link); 952 tu->tp.flags &= ~TP_FLAG_TRACE; 953 } else { 954 tu->tp.flags &= ~TP_FLAG_PROFILE; 955 } 956 return ret; 957 } 958 959 static void 960 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) 961 { 962 if (!trace_probe_is_enabled(&tu->tp)) 963 return; 964 965 if (file) { 966 struct event_file_link *link; 967 968 link = find_event_file_link(&tu->tp, file); 969 if (!link) 970 return; 971 972 list_del_rcu(&link->list); 973 /* synchronize with u{,ret}probe_trace_func */ 974 synchronize_sched(); 975 kfree(link); 976 977 if (!list_empty(&tu->tp.files)) 978 return; 979 } 980 981 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 982 983 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 984 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 985 986 uprobe_buffer_disable(); 987 } 988 989 static int uprobe_event_define_fields(struct trace_event_call *event_call) 990 { 991 int ret, i, size; 992 struct uprobe_trace_entry_head field; 993 struct trace_uprobe *tu = event_call->data; 994 995 if (is_ret_probe(tu)) { 996 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 997 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 998 size = SIZEOF_TRACE_ENTRY(true); 999 } else { 1000 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 1001 size = SIZEOF_TRACE_ENTRY(false); 1002 } 1003 /* Set argument names as fields */ 1004 for (i = 0; i < tu->tp.nr_args; i++) { 1005 struct probe_arg *parg = &tu->tp.args[i]; 1006 1007 ret = trace_define_field(event_call, parg->type->fmttype, 1008 parg->name, size + parg->offset, 1009 parg->type->size, parg->type->is_signed, 1010 FILTER_OTHER); 1011 1012 if (ret) 1013 return ret; 1014 } 1015 return 0; 1016 } 1017 1018 #ifdef CONFIG_PERF_EVENTS 1019 static bool 1020 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1021 { 1022 struct perf_event *event; 1023 1024 if (filter->nr_systemwide) 1025 return true; 1026 1027 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1028 if (event->hw.target->mm == mm) 1029 return true; 1030 } 1031 1032 return false; 1033 } 1034 1035 static inline bool 1036 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1037 { 1038 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1039 } 1040 1041 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1042 { 1043 bool done; 1044 1045 write_lock(&tu->filter.rwlock); 1046 if (event->hw.target) { 1047 list_del(&event->hw.tp_list); 1048 done = tu->filter.nr_systemwide || 1049 (event->hw.target->flags & PF_EXITING) || 1050 uprobe_filter_event(tu, event); 1051 } else { 1052 tu->filter.nr_systemwide--; 1053 done = tu->filter.nr_systemwide; 1054 } 1055 write_unlock(&tu->filter.rwlock); 1056 1057 if (!done) 1058 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1059 1060 return 0; 1061 } 1062 1063 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1064 { 1065 bool done; 1066 int err; 1067 1068 write_lock(&tu->filter.rwlock); 1069 if (event->hw.target) { 1070 /* 1071 * event->parent != NULL means copy_process(), we can avoid 1072 * uprobe_apply(). current->mm must be probed and we can rely 1073 * on dup_mmap() which preserves the already installed bp's. 1074 * 1075 * attr.enable_on_exec means that exec/mmap will install the 1076 * breakpoints we need. 1077 */ 1078 done = tu->filter.nr_systemwide || 1079 event->parent || event->attr.enable_on_exec || 1080 uprobe_filter_event(tu, event); 1081 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1082 } else { 1083 done = tu->filter.nr_systemwide; 1084 tu->filter.nr_systemwide++; 1085 } 1086 write_unlock(&tu->filter.rwlock); 1087 1088 err = 0; 1089 if (!done) { 1090 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1091 if (err) 1092 uprobe_perf_close(tu, event); 1093 } 1094 return err; 1095 } 1096 1097 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1098 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1099 { 1100 struct trace_uprobe *tu; 1101 int ret; 1102 1103 tu = container_of(uc, struct trace_uprobe, consumer); 1104 read_lock(&tu->filter.rwlock); 1105 ret = __uprobe_perf_filter(&tu->filter, mm); 1106 read_unlock(&tu->filter.rwlock); 1107 1108 return ret; 1109 } 1110 1111 static void __uprobe_perf_func(struct trace_uprobe *tu, 1112 unsigned long func, struct pt_regs *regs, 1113 struct uprobe_cpu_buffer *ucb, int dsize) 1114 { 1115 struct trace_event_call *call = &tu->tp.call; 1116 struct uprobe_trace_entry_head *entry; 1117 struct bpf_prog *prog = call->prog; 1118 struct hlist_head *head; 1119 void *data; 1120 int size, esize; 1121 int rctx; 1122 1123 if (prog && !trace_call_bpf(prog, regs)) 1124 return; 1125 1126 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1127 1128 size = esize + tu->tp.size + dsize; 1129 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1130 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1131 return; 1132 1133 preempt_disable(); 1134 head = this_cpu_ptr(call->perf_events); 1135 if (hlist_empty(head)) 1136 goto out; 1137 1138 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1139 if (!entry) 1140 goto out; 1141 1142 if (is_ret_probe(tu)) { 1143 entry->vaddr[0] = func; 1144 entry->vaddr[1] = instruction_pointer(regs); 1145 data = DATAOF_TRACE_ENTRY(entry, true); 1146 } else { 1147 entry->vaddr[0] = instruction_pointer(regs); 1148 data = DATAOF_TRACE_ENTRY(entry, false); 1149 } 1150 1151 memcpy(data, ucb->buf, tu->tp.size + dsize); 1152 1153 if (size - esize > tu->tp.size + dsize) { 1154 int len = tu->tp.size + dsize; 1155 1156 memset(data + len, 0, size - esize - len); 1157 } 1158 1159 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1160 head, NULL); 1161 out: 1162 preempt_enable(); 1163 } 1164 1165 /* uprobe profile handler */ 1166 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1167 struct uprobe_cpu_buffer *ucb, int dsize) 1168 { 1169 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1170 return UPROBE_HANDLER_REMOVE; 1171 1172 if (!is_ret_probe(tu)) 1173 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1174 return 0; 1175 } 1176 1177 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1178 struct pt_regs *regs, 1179 struct uprobe_cpu_buffer *ucb, int dsize) 1180 { 1181 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1182 } 1183 #endif /* CONFIG_PERF_EVENTS */ 1184 1185 static int 1186 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, 1187 void *data) 1188 { 1189 struct trace_uprobe *tu = event->data; 1190 struct trace_event_file *file = data; 1191 1192 switch (type) { 1193 case TRACE_REG_REGISTER: 1194 return probe_event_enable(tu, file, NULL); 1195 1196 case TRACE_REG_UNREGISTER: 1197 probe_event_disable(tu, file); 1198 return 0; 1199 1200 #ifdef CONFIG_PERF_EVENTS 1201 case TRACE_REG_PERF_REGISTER: 1202 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1203 1204 case TRACE_REG_PERF_UNREGISTER: 1205 probe_event_disable(tu, NULL); 1206 return 0; 1207 1208 case TRACE_REG_PERF_OPEN: 1209 return uprobe_perf_open(tu, data); 1210 1211 case TRACE_REG_PERF_CLOSE: 1212 return uprobe_perf_close(tu, data); 1213 1214 #endif 1215 default: 1216 return 0; 1217 } 1218 return 0; 1219 } 1220 1221 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1222 { 1223 struct trace_uprobe *tu; 1224 struct uprobe_dispatch_data udd; 1225 struct uprobe_cpu_buffer *ucb; 1226 int dsize, esize; 1227 int ret = 0; 1228 1229 1230 tu = container_of(con, struct trace_uprobe, consumer); 1231 tu->nhit++; 1232 1233 udd.tu = tu; 1234 udd.bp_addr = instruction_pointer(regs); 1235 1236 current->utask->vaddr = (unsigned long) &udd; 1237 1238 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1239 return 0; 1240 1241 dsize = __get_data_size(&tu->tp, regs); 1242 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1243 1244 ucb = uprobe_buffer_get(); 1245 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1246 1247 if (tu->tp.flags & TP_FLAG_TRACE) 1248 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1249 1250 #ifdef CONFIG_PERF_EVENTS 1251 if (tu->tp.flags & TP_FLAG_PROFILE) 1252 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1253 #endif 1254 uprobe_buffer_put(ucb); 1255 return ret; 1256 } 1257 1258 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1259 unsigned long func, struct pt_regs *regs) 1260 { 1261 struct trace_uprobe *tu; 1262 struct uprobe_dispatch_data udd; 1263 struct uprobe_cpu_buffer *ucb; 1264 int dsize, esize; 1265 1266 tu = container_of(con, struct trace_uprobe, consumer); 1267 1268 udd.tu = tu; 1269 udd.bp_addr = func; 1270 1271 current->utask->vaddr = (unsigned long) &udd; 1272 1273 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1274 return 0; 1275 1276 dsize = __get_data_size(&tu->tp, regs); 1277 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1278 1279 ucb = uprobe_buffer_get(); 1280 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1281 1282 if (tu->tp.flags & TP_FLAG_TRACE) 1283 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1284 1285 #ifdef CONFIG_PERF_EVENTS 1286 if (tu->tp.flags & TP_FLAG_PROFILE) 1287 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1288 #endif 1289 uprobe_buffer_put(ucb); 1290 return 0; 1291 } 1292 1293 static struct trace_event_functions uprobe_funcs = { 1294 .trace = print_uprobe_event 1295 }; 1296 1297 static int register_uprobe_event(struct trace_uprobe *tu) 1298 { 1299 struct trace_event_call *call = &tu->tp.call; 1300 int ret; 1301 1302 /* Initialize trace_event_call */ 1303 INIT_LIST_HEAD(&call->class->fields); 1304 call->event.funcs = &uprobe_funcs; 1305 call->class->define_fields = uprobe_event_define_fields; 1306 1307 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1308 return -ENOMEM; 1309 1310 ret = register_trace_event(&call->event); 1311 if (!ret) { 1312 kfree(call->print_fmt); 1313 return -ENODEV; 1314 } 1315 1316 call->flags = TRACE_EVENT_FL_UPROBE; 1317 call->class->reg = trace_uprobe_register; 1318 call->data = tu; 1319 ret = trace_add_event_call(call); 1320 1321 if (ret) { 1322 pr_info("Failed to register uprobe event: %s\n", 1323 trace_event_name(call)); 1324 kfree(call->print_fmt); 1325 unregister_trace_event(&call->event); 1326 } 1327 1328 return ret; 1329 } 1330 1331 static int unregister_uprobe_event(struct trace_uprobe *tu) 1332 { 1333 int ret; 1334 1335 /* tu->event is unregistered in trace_remove_event_call() */ 1336 ret = trace_remove_event_call(&tu->tp.call); 1337 if (ret) 1338 return ret; 1339 kfree(tu->tp.call.print_fmt); 1340 tu->tp.call.print_fmt = NULL; 1341 return 0; 1342 } 1343 1344 /* Make a trace interface for controling probe points */ 1345 static __init int init_uprobe_trace(void) 1346 { 1347 struct dentry *d_tracer; 1348 1349 d_tracer = tracing_init_dentry(); 1350 if (IS_ERR(d_tracer)) 1351 return 0; 1352 1353 trace_create_file("uprobe_events", 0644, d_tracer, 1354 NULL, &uprobe_events_ops); 1355 /* Profile interface */ 1356 trace_create_file("uprobe_profile", 0444, d_tracer, 1357 NULL, &uprobe_profile_ops); 1358 return 0; 1359 } 1360 1361 fs_initcall(init_uprobe_trace); 1362