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 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(ftrace_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(ftrace_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(path.dentry->d_inode); 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 if (ret) { 540 pr_info("Parse error at argument[%d]. (%d)\n", i, ret); 541 goto error; 542 } 543 } 544 545 ret = register_trace_uprobe(tu); 546 if (ret) 547 goto error; 548 return 0; 549 550 error: 551 free_trace_uprobe(tu); 552 return ret; 553 554 fail_address_parse: 555 iput(inode); 556 557 pr_info("Failed to parse address or file.\n"); 558 559 return ret; 560 } 561 562 static int cleanup_all_probes(void) 563 { 564 struct trace_uprobe *tu; 565 int ret = 0; 566 567 mutex_lock(&uprobe_lock); 568 while (!list_empty(&uprobe_list)) { 569 tu = list_entry(uprobe_list.next, struct trace_uprobe, list); 570 ret = unregister_trace_uprobe(tu); 571 if (ret) 572 break; 573 } 574 mutex_unlock(&uprobe_lock); 575 return ret; 576 } 577 578 /* Probes listing interfaces */ 579 static void *probes_seq_start(struct seq_file *m, loff_t *pos) 580 { 581 mutex_lock(&uprobe_lock); 582 return seq_list_start(&uprobe_list, *pos); 583 } 584 585 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) 586 { 587 return seq_list_next(v, &uprobe_list, pos); 588 } 589 590 static void probes_seq_stop(struct seq_file *m, void *v) 591 { 592 mutex_unlock(&uprobe_lock); 593 } 594 595 static int probes_seq_show(struct seq_file *m, void *v) 596 { 597 struct trace_uprobe *tu = v; 598 char c = is_ret_probe(tu) ? 'r' : 'p'; 599 int i; 600 601 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system, 602 ftrace_event_name(&tu->tp.call)); 603 seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset); 604 605 for (i = 0; i < tu->tp.nr_args; i++) 606 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 607 608 seq_putc(m, '\n'); 609 return 0; 610 } 611 612 static const struct seq_operations probes_seq_op = { 613 .start = probes_seq_start, 614 .next = probes_seq_next, 615 .stop = probes_seq_stop, 616 .show = probes_seq_show 617 }; 618 619 static int probes_open(struct inode *inode, struct file *file) 620 { 621 int ret; 622 623 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 624 ret = cleanup_all_probes(); 625 if (ret) 626 return ret; 627 } 628 629 return seq_open(file, &probes_seq_op); 630 } 631 632 static ssize_t probes_write(struct file *file, const char __user *buffer, 633 size_t count, loff_t *ppos) 634 { 635 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); 636 } 637 638 static const struct file_operations uprobe_events_ops = { 639 .owner = THIS_MODULE, 640 .open = probes_open, 641 .read = seq_read, 642 .llseek = seq_lseek, 643 .release = seq_release, 644 .write = probes_write, 645 }; 646 647 /* Probes profiling interfaces */ 648 static int probes_profile_seq_show(struct seq_file *m, void *v) 649 { 650 struct trace_uprobe *tu = v; 651 652 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 653 ftrace_event_name(&tu->tp.call), tu->nhit); 654 return 0; 655 } 656 657 static const struct seq_operations profile_seq_op = { 658 .start = probes_seq_start, 659 .next = probes_seq_next, 660 .stop = probes_seq_stop, 661 .show = probes_profile_seq_show 662 }; 663 664 static int profile_open(struct inode *inode, struct file *file) 665 { 666 return seq_open(file, &profile_seq_op); 667 } 668 669 static const struct file_operations uprobe_profile_ops = { 670 .owner = THIS_MODULE, 671 .open = profile_open, 672 .read = seq_read, 673 .llseek = seq_lseek, 674 .release = seq_release, 675 }; 676 677 struct uprobe_cpu_buffer { 678 struct mutex mutex; 679 void *buf; 680 }; 681 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 682 static int uprobe_buffer_refcnt; 683 684 static int uprobe_buffer_init(void) 685 { 686 int cpu, err_cpu; 687 688 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 689 if (uprobe_cpu_buffer == NULL) 690 return -ENOMEM; 691 692 for_each_possible_cpu(cpu) { 693 struct page *p = alloc_pages_node(cpu_to_node(cpu), 694 GFP_KERNEL, 0); 695 if (p == NULL) { 696 err_cpu = cpu; 697 goto err; 698 } 699 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 700 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 701 } 702 703 return 0; 704 705 err: 706 for_each_possible_cpu(cpu) { 707 if (cpu == err_cpu) 708 break; 709 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 710 } 711 712 free_percpu(uprobe_cpu_buffer); 713 return -ENOMEM; 714 } 715 716 static int uprobe_buffer_enable(void) 717 { 718 int ret = 0; 719 720 BUG_ON(!mutex_is_locked(&event_mutex)); 721 722 if (uprobe_buffer_refcnt++ == 0) { 723 ret = uprobe_buffer_init(); 724 if (ret < 0) 725 uprobe_buffer_refcnt--; 726 } 727 728 return ret; 729 } 730 731 static void uprobe_buffer_disable(void) 732 { 733 int cpu; 734 735 BUG_ON(!mutex_is_locked(&event_mutex)); 736 737 if (--uprobe_buffer_refcnt == 0) { 738 for_each_possible_cpu(cpu) 739 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 740 cpu)->buf); 741 742 free_percpu(uprobe_cpu_buffer); 743 uprobe_cpu_buffer = NULL; 744 } 745 } 746 747 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 748 { 749 struct uprobe_cpu_buffer *ucb; 750 int cpu; 751 752 cpu = raw_smp_processor_id(); 753 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 754 755 /* 756 * Use per-cpu buffers for fastest access, but we might migrate 757 * so the mutex makes sure we have sole access to it. 758 */ 759 mutex_lock(&ucb->mutex); 760 761 return ucb; 762 } 763 764 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 765 { 766 mutex_unlock(&ucb->mutex); 767 } 768 769 static void __uprobe_trace_func(struct trace_uprobe *tu, 770 unsigned long func, struct pt_regs *regs, 771 struct uprobe_cpu_buffer *ucb, int dsize, 772 struct ftrace_event_file *ftrace_file) 773 { 774 struct uprobe_trace_entry_head *entry; 775 struct ring_buffer_event *event; 776 struct ring_buffer *buffer; 777 void *data; 778 int size, esize; 779 struct ftrace_event_call *call = &tu->tp.call; 780 781 WARN_ON(call != ftrace_file->event_call); 782 783 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 784 return; 785 786 if (ftrace_trigger_soft_disabled(ftrace_file)) 787 return; 788 789 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 790 size = esize + tu->tp.size + dsize; 791 event = trace_event_buffer_lock_reserve(&buffer, ftrace_file, 792 call->event.type, size, 0, 0); 793 if (!event) 794 return; 795 796 entry = ring_buffer_event_data(event); 797 if (is_ret_probe(tu)) { 798 entry->vaddr[0] = func; 799 entry->vaddr[1] = instruction_pointer(regs); 800 data = DATAOF_TRACE_ENTRY(entry, true); 801 } else { 802 entry->vaddr[0] = instruction_pointer(regs); 803 data = DATAOF_TRACE_ENTRY(entry, false); 804 } 805 806 memcpy(data, ucb->buf, tu->tp.size + dsize); 807 808 event_trigger_unlock_commit(ftrace_file, buffer, event, entry, 0, 0); 809 } 810 811 /* uprobe handler */ 812 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 813 struct uprobe_cpu_buffer *ucb, int dsize) 814 { 815 struct event_file_link *link; 816 817 if (is_ret_probe(tu)) 818 return 0; 819 820 rcu_read_lock(); 821 list_for_each_entry_rcu(link, &tu->tp.files, list) 822 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 823 rcu_read_unlock(); 824 825 return 0; 826 } 827 828 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 829 struct pt_regs *regs, 830 struct uprobe_cpu_buffer *ucb, int dsize) 831 { 832 struct event_file_link *link; 833 834 rcu_read_lock(); 835 list_for_each_entry_rcu(link, &tu->tp.files, list) 836 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 837 rcu_read_unlock(); 838 } 839 840 /* Event entry printers */ 841 static enum print_line_t 842 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 843 { 844 struct uprobe_trace_entry_head *entry; 845 struct trace_seq *s = &iter->seq; 846 struct trace_uprobe *tu; 847 u8 *data; 848 int i; 849 850 entry = (struct uprobe_trace_entry_head *)iter->ent; 851 tu = container_of(event, struct trace_uprobe, tp.call.event); 852 853 if (is_ret_probe(tu)) { 854 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 855 ftrace_event_name(&tu->tp.call), 856 entry->vaddr[1], entry->vaddr[0]); 857 data = DATAOF_TRACE_ENTRY(entry, true); 858 } else { 859 trace_seq_printf(s, "%s: (0x%lx)", 860 ftrace_event_name(&tu->tp.call), 861 entry->vaddr[0]); 862 data = DATAOF_TRACE_ENTRY(entry, false); 863 } 864 865 for (i = 0; i < tu->tp.nr_args; i++) { 866 struct probe_arg *parg = &tu->tp.args[i]; 867 868 if (!parg->type->print(s, parg->name, data + parg->offset, entry)) 869 goto out; 870 } 871 872 trace_seq_putc(s, '\n'); 873 874 out: 875 return trace_handle_return(s); 876 } 877 878 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 879 enum uprobe_filter_ctx ctx, 880 struct mm_struct *mm); 881 882 static int 883 probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file, 884 filter_func_t filter) 885 { 886 bool enabled = trace_probe_is_enabled(&tu->tp); 887 struct event_file_link *link = NULL; 888 int ret; 889 890 if (file) { 891 if (tu->tp.flags & TP_FLAG_PROFILE) 892 return -EINTR; 893 894 link = kmalloc(sizeof(*link), GFP_KERNEL); 895 if (!link) 896 return -ENOMEM; 897 898 link->file = file; 899 list_add_tail_rcu(&link->list, &tu->tp.files); 900 901 tu->tp.flags |= TP_FLAG_TRACE; 902 } else { 903 if (tu->tp.flags & TP_FLAG_TRACE) 904 return -EINTR; 905 906 tu->tp.flags |= TP_FLAG_PROFILE; 907 } 908 909 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 910 911 if (enabled) 912 return 0; 913 914 ret = uprobe_buffer_enable(); 915 if (ret) 916 goto err_flags; 917 918 tu->consumer.filter = filter; 919 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 920 if (ret) 921 goto err_buffer; 922 923 return 0; 924 925 err_buffer: 926 uprobe_buffer_disable(); 927 928 err_flags: 929 if (file) { 930 list_del(&link->list); 931 kfree(link); 932 tu->tp.flags &= ~TP_FLAG_TRACE; 933 } else { 934 tu->tp.flags &= ~TP_FLAG_PROFILE; 935 } 936 return ret; 937 } 938 939 static void 940 probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file) 941 { 942 if (!trace_probe_is_enabled(&tu->tp)) 943 return; 944 945 if (file) { 946 struct event_file_link *link; 947 948 link = find_event_file_link(&tu->tp, file); 949 if (!link) 950 return; 951 952 list_del_rcu(&link->list); 953 /* synchronize with u{,ret}probe_trace_func */ 954 synchronize_sched(); 955 kfree(link); 956 957 if (!list_empty(&tu->tp.files)) 958 return; 959 } 960 961 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 962 963 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 964 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 965 966 uprobe_buffer_disable(); 967 } 968 969 static int uprobe_event_define_fields(struct ftrace_event_call *event_call) 970 { 971 int ret, i, size; 972 struct uprobe_trace_entry_head field; 973 struct trace_uprobe *tu = event_call->data; 974 975 if (is_ret_probe(tu)) { 976 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 977 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 978 size = SIZEOF_TRACE_ENTRY(true); 979 } else { 980 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 981 size = SIZEOF_TRACE_ENTRY(false); 982 } 983 /* Set argument names as fields */ 984 for (i = 0; i < tu->tp.nr_args; i++) { 985 struct probe_arg *parg = &tu->tp.args[i]; 986 987 ret = trace_define_field(event_call, parg->type->fmttype, 988 parg->name, size + parg->offset, 989 parg->type->size, parg->type->is_signed, 990 FILTER_OTHER); 991 992 if (ret) 993 return ret; 994 } 995 return 0; 996 } 997 998 #ifdef CONFIG_PERF_EVENTS 999 static bool 1000 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1001 { 1002 struct perf_event *event; 1003 1004 if (filter->nr_systemwide) 1005 return true; 1006 1007 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1008 if (event->hw.tp_target->mm == mm) 1009 return true; 1010 } 1011 1012 return false; 1013 } 1014 1015 static inline bool 1016 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1017 { 1018 return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm); 1019 } 1020 1021 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1022 { 1023 bool done; 1024 1025 write_lock(&tu->filter.rwlock); 1026 if (event->hw.tp_target) { 1027 list_del(&event->hw.tp_list); 1028 done = tu->filter.nr_systemwide || 1029 (event->hw.tp_target->flags & PF_EXITING) || 1030 uprobe_filter_event(tu, event); 1031 } else { 1032 tu->filter.nr_systemwide--; 1033 done = tu->filter.nr_systemwide; 1034 } 1035 write_unlock(&tu->filter.rwlock); 1036 1037 if (!done) 1038 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1039 1040 return 0; 1041 } 1042 1043 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1044 { 1045 bool done; 1046 int err; 1047 1048 write_lock(&tu->filter.rwlock); 1049 if (event->hw.tp_target) { 1050 /* 1051 * event->parent != NULL means copy_process(), we can avoid 1052 * uprobe_apply(). current->mm must be probed and we can rely 1053 * on dup_mmap() which preserves the already installed bp's. 1054 * 1055 * attr.enable_on_exec means that exec/mmap will install the 1056 * breakpoints we need. 1057 */ 1058 done = tu->filter.nr_systemwide || 1059 event->parent || event->attr.enable_on_exec || 1060 uprobe_filter_event(tu, event); 1061 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1062 } else { 1063 done = tu->filter.nr_systemwide; 1064 tu->filter.nr_systemwide++; 1065 } 1066 write_unlock(&tu->filter.rwlock); 1067 1068 err = 0; 1069 if (!done) { 1070 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1071 if (err) 1072 uprobe_perf_close(tu, event); 1073 } 1074 return err; 1075 } 1076 1077 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1078 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1079 { 1080 struct trace_uprobe *tu; 1081 int ret; 1082 1083 tu = container_of(uc, struct trace_uprobe, consumer); 1084 read_lock(&tu->filter.rwlock); 1085 ret = __uprobe_perf_filter(&tu->filter, mm); 1086 read_unlock(&tu->filter.rwlock); 1087 1088 return ret; 1089 } 1090 1091 static void __uprobe_perf_func(struct trace_uprobe *tu, 1092 unsigned long func, struct pt_regs *regs, 1093 struct uprobe_cpu_buffer *ucb, int dsize) 1094 { 1095 struct ftrace_event_call *call = &tu->tp.call; 1096 struct uprobe_trace_entry_head *entry; 1097 struct hlist_head *head; 1098 void *data; 1099 int size, esize; 1100 int rctx; 1101 1102 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1103 1104 size = esize + tu->tp.size + dsize; 1105 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1106 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1107 return; 1108 1109 preempt_disable(); 1110 head = this_cpu_ptr(call->perf_events); 1111 if (hlist_empty(head)) 1112 goto out; 1113 1114 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); 1115 if (!entry) 1116 goto out; 1117 1118 if (is_ret_probe(tu)) { 1119 entry->vaddr[0] = func; 1120 entry->vaddr[1] = instruction_pointer(regs); 1121 data = DATAOF_TRACE_ENTRY(entry, true); 1122 } else { 1123 entry->vaddr[0] = instruction_pointer(regs); 1124 data = DATAOF_TRACE_ENTRY(entry, false); 1125 } 1126 1127 memcpy(data, ucb->buf, tu->tp.size + dsize); 1128 1129 if (size - esize > tu->tp.size + dsize) { 1130 int len = tu->tp.size + dsize; 1131 1132 memset(data + len, 0, size - esize - len); 1133 } 1134 1135 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL); 1136 out: 1137 preempt_enable(); 1138 } 1139 1140 /* uprobe profile handler */ 1141 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1142 struct uprobe_cpu_buffer *ucb, int dsize) 1143 { 1144 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1145 return UPROBE_HANDLER_REMOVE; 1146 1147 if (!is_ret_probe(tu)) 1148 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1149 return 0; 1150 } 1151 1152 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1153 struct pt_regs *regs, 1154 struct uprobe_cpu_buffer *ucb, int dsize) 1155 { 1156 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1157 } 1158 #endif /* CONFIG_PERF_EVENTS */ 1159 1160 static int 1161 trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, 1162 void *data) 1163 { 1164 struct trace_uprobe *tu = event->data; 1165 struct ftrace_event_file *file = data; 1166 1167 switch (type) { 1168 case TRACE_REG_REGISTER: 1169 return probe_event_enable(tu, file, NULL); 1170 1171 case TRACE_REG_UNREGISTER: 1172 probe_event_disable(tu, file); 1173 return 0; 1174 1175 #ifdef CONFIG_PERF_EVENTS 1176 case TRACE_REG_PERF_REGISTER: 1177 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1178 1179 case TRACE_REG_PERF_UNREGISTER: 1180 probe_event_disable(tu, NULL); 1181 return 0; 1182 1183 case TRACE_REG_PERF_OPEN: 1184 return uprobe_perf_open(tu, data); 1185 1186 case TRACE_REG_PERF_CLOSE: 1187 return uprobe_perf_close(tu, data); 1188 1189 #endif 1190 default: 1191 return 0; 1192 } 1193 return 0; 1194 } 1195 1196 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1197 { 1198 struct trace_uprobe *tu; 1199 struct uprobe_dispatch_data udd; 1200 struct uprobe_cpu_buffer *ucb; 1201 int dsize, esize; 1202 int ret = 0; 1203 1204 1205 tu = container_of(con, struct trace_uprobe, consumer); 1206 tu->nhit++; 1207 1208 udd.tu = tu; 1209 udd.bp_addr = instruction_pointer(regs); 1210 1211 current->utask->vaddr = (unsigned long) &udd; 1212 1213 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1214 return 0; 1215 1216 dsize = __get_data_size(&tu->tp, regs); 1217 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1218 1219 ucb = uprobe_buffer_get(); 1220 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1221 1222 if (tu->tp.flags & TP_FLAG_TRACE) 1223 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1224 1225 #ifdef CONFIG_PERF_EVENTS 1226 if (tu->tp.flags & TP_FLAG_PROFILE) 1227 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1228 #endif 1229 uprobe_buffer_put(ucb); 1230 return ret; 1231 } 1232 1233 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1234 unsigned long func, struct pt_regs *regs) 1235 { 1236 struct trace_uprobe *tu; 1237 struct uprobe_dispatch_data udd; 1238 struct uprobe_cpu_buffer *ucb; 1239 int dsize, esize; 1240 1241 tu = container_of(con, struct trace_uprobe, consumer); 1242 1243 udd.tu = tu; 1244 udd.bp_addr = func; 1245 1246 current->utask->vaddr = (unsigned long) &udd; 1247 1248 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1249 return 0; 1250 1251 dsize = __get_data_size(&tu->tp, regs); 1252 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1253 1254 ucb = uprobe_buffer_get(); 1255 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1256 1257 if (tu->tp.flags & TP_FLAG_TRACE) 1258 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1259 1260 #ifdef CONFIG_PERF_EVENTS 1261 if (tu->tp.flags & TP_FLAG_PROFILE) 1262 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1263 #endif 1264 uprobe_buffer_put(ucb); 1265 return 0; 1266 } 1267 1268 static struct trace_event_functions uprobe_funcs = { 1269 .trace = print_uprobe_event 1270 }; 1271 1272 static int register_uprobe_event(struct trace_uprobe *tu) 1273 { 1274 struct ftrace_event_call *call = &tu->tp.call; 1275 int ret; 1276 1277 /* Initialize ftrace_event_call */ 1278 INIT_LIST_HEAD(&call->class->fields); 1279 call->event.funcs = &uprobe_funcs; 1280 call->class->define_fields = uprobe_event_define_fields; 1281 1282 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1283 return -ENOMEM; 1284 1285 ret = register_ftrace_event(&call->event); 1286 if (!ret) { 1287 kfree(call->print_fmt); 1288 return -ENODEV; 1289 } 1290 1291 call->class->reg = trace_uprobe_register; 1292 call->data = tu; 1293 ret = trace_add_event_call(call); 1294 1295 if (ret) { 1296 pr_info("Failed to register uprobe event: %s\n", 1297 ftrace_event_name(call)); 1298 kfree(call->print_fmt); 1299 unregister_ftrace_event(&call->event); 1300 } 1301 1302 return ret; 1303 } 1304 1305 static int unregister_uprobe_event(struct trace_uprobe *tu) 1306 { 1307 int ret; 1308 1309 /* tu->event is unregistered in trace_remove_event_call() */ 1310 ret = trace_remove_event_call(&tu->tp.call); 1311 if (ret) 1312 return ret; 1313 kfree(tu->tp.call.print_fmt); 1314 tu->tp.call.print_fmt = NULL; 1315 return 0; 1316 } 1317 1318 /* Make a trace interface for controling probe points */ 1319 static __init int init_uprobe_trace(void) 1320 { 1321 struct dentry *d_tracer; 1322 1323 d_tracer = tracing_init_dentry(); 1324 if (!d_tracer) 1325 return 0; 1326 1327 trace_create_file("uprobe_events", 0644, d_tracer, 1328 NULL, &uprobe_events_ops); 1329 /* Profile interface */ 1330 trace_create_file("uprobe_profile", 0444, d_tracer, 1331 NULL, &uprobe_profile_ops); 1332 return 0; 1333 } 1334 1335 fs_initcall(init_uprobe_trace); 1336