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 #define pr_fmt(fmt) "trace_kprobe: " fmt 21 22 #include <linux/module.h> 23 #include <linux/uaccess.h> 24 #include <linux/uprobes.h> 25 #include <linux/namei.h> 26 #include <linux/string.h> 27 #include <linux/rculist.h> 28 29 #include "trace_probe.h" 30 31 #define UPROBE_EVENT_SYSTEM "uprobes" 32 33 struct uprobe_trace_entry_head { 34 struct trace_entry ent; 35 unsigned long vaddr[]; 36 }; 37 38 #define SIZEOF_TRACE_ENTRY(is_return) \ 39 (sizeof(struct uprobe_trace_entry_head) + \ 40 sizeof(unsigned long) * (is_return ? 2 : 1)) 41 42 #define DATAOF_TRACE_ENTRY(entry, is_return) \ 43 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) 44 45 struct trace_uprobe_filter { 46 rwlock_t rwlock; 47 int nr_systemwide; 48 struct list_head perf_events; 49 }; 50 51 /* 52 * uprobe event core functions 53 */ 54 struct trace_uprobe { 55 struct list_head list; 56 struct trace_uprobe_filter filter; 57 struct uprobe_consumer consumer; 58 struct inode *inode; 59 char *filename; 60 unsigned long offset; 61 unsigned long nhit; 62 struct trace_probe tp; 63 }; 64 65 #define SIZEOF_TRACE_UPROBE(n) \ 66 (offsetof(struct trace_uprobe, tp.args) + \ 67 (sizeof(struct probe_arg) * (n))) 68 69 static int register_uprobe_event(struct trace_uprobe *tu); 70 static int unregister_uprobe_event(struct trace_uprobe *tu); 71 72 static DEFINE_MUTEX(uprobe_lock); 73 static LIST_HEAD(uprobe_list); 74 75 struct uprobe_dispatch_data { 76 struct trace_uprobe *tu; 77 unsigned long bp_addr; 78 }; 79 80 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); 81 static int uretprobe_dispatcher(struct uprobe_consumer *con, 82 unsigned long func, struct pt_regs *regs); 83 84 #ifdef CONFIG_STACK_GROWSUP 85 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 86 { 87 return addr - (n * sizeof(long)); 88 } 89 #else 90 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 91 { 92 return addr + (n * sizeof(long)); 93 } 94 #endif 95 96 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) 97 { 98 unsigned long ret; 99 unsigned long addr = user_stack_pointer(regs); 100 101 addr = adjust_stack_addr(addr, n); 102 103 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) 104 return 0; 105 106 return ret; 107 } 108 109 /* 110 * Uprobes-specific fetch functions 111 */ 112 #define DEFINE_FETCH_stack(type) \ 113 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \ 114 void *offset, void *dest) \ 115 { \ 116 *(type *)dest = (type)get_user_stack_nth(regs, \ 117 ((unsigned long)offset)); \ 118 } 119 DEFINE_BASIC_FETCH_FUNCS(stack) 120 /* No string on the stack entry */ 121 #define fetch_stack_string NULL 122 #define fetch_stack_string_size NULL 123 124 #define DEFINE_FETCH_memory(type) \ 125 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \ 126 void *addr, void *dest) \ 127 { \ 128 type retval; \ 129 void __user *vaddr = (void __force __user *) addr; \ 130 \ 131 if (copy_from_user(&retval, vaddr, sizeof(type))) \ 132 *(type *)dest = 0; \ 133 else \ 134 *(type *) dest = retval; \ 135 } 136 DEFINE_BASIC_FETCH_FUNCS(memory) 137 /* 138 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max 139 * length and relative data location. 140 */ 141 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, 142 void *addr, void *dest) 143 { 144 long ret; 145 u32 rloc = *(u32 *)dest; 146 int maxlen = get_rloc_len(rloc); 147 u8 *dst = get_rloc_data(dest); 148 void __user *src = (void __force __user *) addr; 149 150 if (!maxlen) 151 return; 152 153 ret = strncpy_from_user(dst, src, maxlen); 154 155 if (ret < 0) { /* Failed to fetch string */ 156 ((u8 *)get_rloc_data(dest))[0] = '\0'; 157 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc)); 158 } else { 159 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc)); 160 } 161 } 162 163 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, 164 void *addr, void *dest) 165 { 166 int len; 167 void __user *vaddr = (void __force __user *) addr; 168 169 len = strnlen_user(vaddr, MAX_STRING_SIZE); 170 171 if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */ 172 *(u32 *)dest = 0; 173 else 174 *(u32 *)dest = len; 175 } 176 177 static unsigned long translate_user_vaddr(void *file_offset) 178 { 179 unsigned long base_addr; 180 struct uprobe_dispatch_data *udd; 181 182 udd = (void *) current->utask->vaddr; 183 184 base_addr = udd->bp_addr - udd->tu->offset; 185 return base_addr + (unsigned long)file_offset; 186 } 187 188 #define DEFINE_FETCH_file_offset(type) \ 189 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs, \ 190 void *offset, void *dest)\ 191 { \ 192 void *vaddr = (void *)translate_user_vaddr(offset); \ 193 \ 194 FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \ 195 } 196 DEFINE_BASIC_FETCH_FUNCS(file_offset) 197 DEFINE_FETCH_file_offset(string) 198 DEFINE_FETCH_file_offset(string_size) 199 200 /* Fetch type information table */ 201 static const struct fetch_type uprobes_fetch_type_table[] = { 202 /* Special types */ 203 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string, 204 sizeof(u32), 1, "__data_loc char[]"), 205 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32, 206 string_size, sizeof(u32), 0, "u32"), 207 /* Basic types */ 208 ASSIGN_FETCH_TYPE(u8, u8, 0), 209 ASSIGN_FETCH_TYPE(u16, u16, 0), 210 ASSIGN_FETCH_TYPE(u32, u32, 0), 211 ASSIGN_FETCH_TYPE(u64, u64, 0), 212 ASSIGN_FETCH_TYPE(s8, u8, 1), 213 ASSIGN_FETCH_TYPE(s16, u16, 1), 214 ASSIGN_FETCH_TYPE(s32, u32, 1), 215 ASSIGN_FETCH_TYPE(s64, u64, 1), 216 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0), 217 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), 218 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), 219 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), 220 221 ASSIGN_FETCH_TYPE_END 222 }; 223 224 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) 225 { 226 rwlock_init(&filter->rwlock); 227 filter->nr_systemwide = 0; 228 INIT_LIST_HEAD(&filter->perf_events); 229 } 230 231 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 232 { 233 return !filter->nr_systemwide && list_empty(&filter->perf_events); 234 } 235 236 static inline bool is_ret_probe(struct trace_uprobe *tu) 237 { 238 return tu->consumer.ret_handler != NULL; 239 } 240 241 /* 242 * Allocate new trace_uprobe and initialize it (including uprobes). 243 */ 244 static struct trace_uprobe * 245 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 246 { 247 struct trace_uprobe *tu; 248 249 if (!event || !is_good_name(event)) 250 return ERR_PTR(-EINVAL); 251 252 if (!group || !is_good_name(group)) 253 return ERR_PTR(-EINVAL); 254 255 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); 256 if (!tu) 257 return ERR_PTR(-ENOMEM); 258 259 tu->tp.call.class = &tu->tp.class; 260 tu->tp.call.name = kstrdup(event, GFP_KERNEL); 261 if (!tu->tp.call.name) 262 goto error; 263 264 tu->tp.class.system = kstrdup(group, GFP_KERNEL); 265 if (!tu->tp.class.system) 266 goto error; 267 268 INIT_LIST_HEAD(&tu->list); 269 INIT_LIST_HEAD(&tu->tp.files); 270 tu->consumer.handler = uprobe_dispatcher; 271 if (is_ret) 272 tu->consumer.ret_handler = uretprobe_dispatcher; 273 init_trace_uprobe_filter(&tu->filter); 274 return tu; 275 276 error: 277 kfree(tu->tp.call.name); 278 kfree(tu); 279 280 return ERR_PTR(-ENOMEM); 281 } 282 283 static void free_trace_uprobe(struct trace_uprobe *tu) 284 { 285 int i; 286 287 for (i = 0; i < tu->tp.nr_args; i++) 288 traceprobe_free_probe_arg(&tu->tp.args[i]); 289 290 iput(tu->inode); 291 kfree(tu->tp.call.class->system); 292 kfree(tu->tp.call.name); 293 kfree(tu->filename); 294 kfree(tu); 295 } 296 297 static struct trace_uprobe *find_probe_event(const char *event, const char *group) 298 { 299 struct trace_uprobe *tu; 300 301 list_for_each_entry(tu, &uprobe_list, list) 302 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 && 303 strcmp(tu->tp.call.class->system, group) == 0) 304 return tu; 305 306 return NULL; 307 } 308 309 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ 310 static int unregister_trace_uprobe(struct trace_uprobe *tu) 311 { 312 int ret; 313 314 ret = unregister_uprobe_event(tu); 315 if (ret) 316 return ret; 317 318 list_del(&tu->list); 319 free_trace_uprobe(tu); 320 return 0; 321 } 322 323 /* Register a trace_uprobe and probe_event */ 324 static int register_trace_uprobe(struct trace_uprobe *tu) 325 { 326 struct trace_uprobe *old_tu; 327 int ret; 328 329 mutex_lock(&uprobe_lock); 330 331 /* register as an event */ 332 old_tu = find_probe_event(trace_event_name(&tu->tp.call), 333 tu->tp.call.class->system); 334 if (old_tu) { 335 /* delete old event */ 336 ret = unregister_trace_uprobe(old_tu); 337 if (ret) 338 goto end; 339 } 340 341 ret = register_uprobe_event(tu); 342 if (ret) { 343 pr_warn("Failed to register probe event(%d)\n", ret); 344 goto end; 345 } 346 347 list_add_tail(&tu->list, &uprobe_list); 348 349 end: 350 mutex_unlock(&uprobe_lock); 351 352 return ret; 353 } 354 355 /* 356 * Argument syntax: 357 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] 358 * 359 * - Remove uprobe: -:[GRP/]EVENT 360 */ 361 static int create_trace_uprobe(int argc, char **argv) 362 { 363 struct trace_uprobe *tu; 364 struct inode *inode; 365 char *arg, *event, *group, *filename; 366 char buf[MAX_EVENT_NAME_LEN]; 367 struct path path; 368 unsigned long offset; 369 bool is_delete, is_return; 370 int i, ret; 371 372 inode = NULL; 373 ret = 0; 374 is_delete = false; 375 is_return = false; 376 event = NULL; 377 group = NULL; 378 379 /* argc must be >= 1 */ 380 if (argv[0][0] == '-') 381 is_delete = true; 382 else if (argv[0][0] == 'r') 383 is_return = true; 384 else if (argv[0][0] != 'p') { 385 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n"); 386 return -EINVAL; 387 } 388 389 if (argv[0][1] == ':') { 390 event = &argv[0][2]; 391 arg = strchr(event, '/'); 392 393 if (arg) { 394 group = event; 395 event = arg + 1; 396 event[-1] = '\0'; 397 398 if (strlen(group) == 0) { 399 pr_info("Group name is not specified\n"); 400 return -EINVAL; 401 } 402 } 403 if (strlen(event) == 0) { 404 pr_info("Event name is not specified\n"); 405 return -EINVAL; 406 } 407 } 408 if (!group) 409 group = UPROBE_EVENT_SYSTEM; 410 411 if (is_delete) { 412 int ret; 413 414 if (!event) { 415 pr_info("Delete command needs an event name.\n"); 416 return -EINVAL; 417 } 418 mutex_lock(&uprobe_lock); 419 tu = find_probe_event(event, group); 420 421 if (!tu) { 422 mutex_unlock(&uprobe_lock); 423 pr_info("Event %s/%s doesn't exist.\n", group, event); 424 return -ENOENT; 425 } 426 /* delete an event */ 427 ret = unregister_trace_uprobe(tu); 428 mutex_unlock(&uprobe_lock); 429 return ret; 430 } 431 432 if (argc < 2) { 433 pr_info("Probe point is not specified.\n"); 434 return -EINVAL; 435 } 436 /* Find the last occurrence, in case the path contains ':' too. */ 437 arg = strrchr(argv[1], ':'); 438 if (!arg) { 439 ret = -EINVAL; 440 goto fail_address_parse; 441 } 442 443 *arg++ = '\0'; 444 filename = argv[1]; 445 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 446 if (ret) 447 goto fail_address_parse; 448 449 inode = igrab(d_inode(path.dentry)); 450 path_put(&path); 451 452 if (!inode || !S_ISREG(inode->i_mode)) { 453 ret = -EINVAL; 454 goto fail_address_parse; 455 } 456 457 ret = kstrtoul(arg, 0, &offset); 458 if (ret) 459 goto fail_address_parse; 460 461 argc -= 2; 462 argv += 2; 463 464 /* setup a probe */ 465 if (!event) { 466 char *tail; 467 char *ptr; 468 469 tail = kstrdup(kbasename(filename), GFP_KERNEL); 470 if (!tail) { 471 ret = -ENOMEM; 472 goto fail_address_parse; 473 } 474 475 ptr = strpbrk(tail, ".-_"); 476 if (ptr) 477 *ptr = '\0'; 478 479 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 480 event = buf; 481 kfree(tail); 482 } 483 484 tu = alloc_trace_uprobe(group, event, argc, is_return); 485 if (IS_ERR(tu)) { 486 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); 487 ret = PTR_ERR(tu); 488 goto fail_address_parse; 489 } 490 tu->offset = offset; 491 tu->inode = inode; 492 tu->filename = kstrdup(filename, GFP_KERNEL); 493 494 if (!tu->filename) { 495 pr_info("Failed to allocate filename.\n"); 496 ret = -ENOMEM; 497 goto error; 498 } 499 500 /* parse arguments */ 501 ret = 0; 502 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 503 struct probe_arg *parg = &tu->tp.args[i]; 504 505 /* Increment count for freeing args in error case */ 506 tu->tp.nr_args++; 507 508 /* Parse argument name */ 509 arg = strchr(argv[i], '='); 510 if (arg) { 511 *arg++ = '\0'; 512 parg->name = kstrdup(argv[i], GFP_KERNEL); 513 } else { 514 arg = argv[i]; 515 /* If argument name is omitted, set "argN" */ 516 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); 517 parg->name = kstrdup(buf, GFP_KERNEL); 518 } 519 520 if (!parg->name) { 521 pr_info("Failed to allocate argument[%d] name.\n", i); 522 ret = -ENOMEM; 523 goto error; 524 } 525 526 if (!is_good_name(parg->name)) { 527 pr_info("Invalid argument[%d] name: %s\n", i, parg->name); 528 ret = -EINVAL; 529 goto error; 530 } 531 532 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) { 533 pr_info("Argument[%d] name '%s' conflicts with " 534 "another field.\n", i, argv[i]); 535 ret = -EINVAL; 536 goto error; 537 } 538 539 /* Parse fetch argument */ 540 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg, 541 is_return, false, 542 uprobes_fetch_type_table); 543 if (ret) { 544 pr_info("Parse error at argument[%d]. (%d)\n", i, ret); 545 goto error; 546 } 547 } 548 549 ret = register_trace_uprobe(tu); 550 if (ret) 551 goto error; 552 return 0; 553 554 error: 555 free_trace_uprobe(tu); 556 return ret; 557 558 fail_address_parse: 559 iput(inode); 560 561 pr_info("Failed to parse address or file.\n"); 562 563 return ret; 564 } 565 566 static int cleanup_all_probes(void) 567 { 568 struct trace_uprobe *tu; 569 int ret = 0; 570 571 mutex_lock(&uprobe_lock); 572 while (!list_empty(&uprobe_list)) { 573 tu = list_entry(uprobe_list.next, struct trace_uprobe, list); 574 ret = unregister_trace_uprobe(tu); 575 if (ret) 576 break; 577 } 578 mutex_unlock(&uprobe_lock); 579 return ret; 580 } 581 582 /* Probes listing interfaces */ 583 static void *probes_seq_start(struct seq_file *m, loff_t *pos) 584 { 585 mutex_lock(&uprobe_lock); 586 return seq_list_start(&uprobe_list, *pos); 587 } 588 589 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) 590 { 591 return seq_list_next(v, &uprobe_list, pos); 592 } 593 594 static void probes_seq_stop(struct seq_file *m, void *v) 595 { 596 mutex_unlock(&uprobe_lock); 597 } 598 599 static int probes_seq_show(struct seq_file *m, void *v) 600 { 601 struct trace_uprobe *tu = v; 602 char c = is_ret_probe(tu) ? 'r' : 'p'; 603 int i; 604 605 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system, 606 trace_event_name(&tu->tp.call)); 607 seq_printf(m, " %s:", tu->filename); 608 609 /* Don't print "0x (null)" when offset is 0 */ 610 if (tu->offset) { 611 seq_printf(m, "0x%px", (void *)tu->offset); 612 } else { 613 switch (sizeof(void *)) { 614 case 4: 615 seq_printf(m, "0x00000000"); 616 break; 617 case 8: 618 default: 619 seq_printf(m, "0x0000000000000000"); 620 break; 621 } 622 } 623 624 for (i = 0; i < tu->tp.nr_args; i++) 625 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 626 627 seq_putc(m, '\n'); 628 return 0; 629 } 630 631 static const struct seq_operations probes_seq_op = { 632 .start = probes_seq_start, 633 .next = probes_seq_next, 634 .stop = probes_seq_stop, 635 .show = probes_seq_show 636 }; 637 638 static int probes_open(struct inode *inode, struct file *file) 639 { 640 int ret; 641 642 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 643 ret = cleanup_all_probes(); 644 if (ret) 645 return ret; 646 } 647 648 return seq_open(file, &probes_seq_op); 649 } 650 651 static ssize_t probes_write(struct file *file, const char __user *buffer, 652 size_t count, loff_t *ppos) 653 { 654 return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe); 655 } 656 657 static const struct file_operations uprobe_events_ops = { 658 .owner = THIS_MODULE, 659 .open = probes_open, 660 .read = seq_read, 661 .llseek = seq_lseek, 662 .release = seq_release, 663 .write = probes_write, 664 }; 665 666 /* Probes profiling interfaces */ 667 static int probes_profile_seq_show(struct seq_file *m, void *v) 668 { 669 struct trace_uprobe *tu = v; 670 671 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 672 trace_event_name(&tu->tp.call), tu->nhit); 673 return 0; 674 } 675 676 static const struct seq_operations profile_seq_op = { 677 .start = probes_seq_start, 678 .next = probes_seq_next, 679 .stop = probes_seq_stop, 680 .show = probes_profile_seq_show 681 }; 682 683 static int profile_open(struct inode *inode, struct file *file) 684 { 685 return seq_open(file, &profile_seq_op); 686 } 687 688 static const struct file_operations uprobe_profile_ops = { 689 .owner = THIS_MODULE, 690 .open = profile_open, 691 .read = seq_read, 692 .llseek = seq_lseek, 693 .release = seq_release, 694 }; 695 696 struct uprobe_cpu_buffer { 697 struct mutex mutex; 698 void *buf; 699 }; 700 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 701 static int uprobe_buffer_refcnt; 702 703 static int uprobe_buffer_init(void) 704 { 705 int cpu, err_cpu; 706 707 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 708 if (uprobe_cpu_buffer == NULL) 709 return -ENOMEM; 710 711 for_each_possible_cpu(cpu) { 712 struct page *p = alloc_pages_node(cpu_to_node(cpu), 713 GFP_KERNEL, 0); 714 if (p == NULL) { 715 err_cpu = cpu; 716 goto err; 717 } 718 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 719 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 720 } 721 722 return 0; 723 724 err: 725 for_each_possible_cpu(cpu) { 726 if (cpu == err_cpu) 727 break; 728 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 729 } 730 731 free_percpu(uprobe_cpu_buffer); 732 return -ENOMEM; 733 } 734 735 static int uprobe_buffer_enable(void) 736 { 737 int ret = 0; 738 739 BUG_ON(!mutex_is_locked(&event_mutex)); 740 741 if (uprobe_buffer_refcnt++ == 0) { 742 ret = uprobe_buffer_init(); 743 if (ret < 0) 744 uprobe_buffer_refcnt--; 745 } 746 747 return ret; 748 } 749 750 static void uprobe_buffer_disable(void) 751 { 752 int cpu; 753 754 BUG_ON(!mutex_is_locked(&event_mutex)); 755 756 if (--uprobe_buffer_refcnt == 0) { 757 for_each_possible_cpu(cpu) 758 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 759 cpu)->buf); 760 761 free_percpu(uprobe_cpu_buffer); 762 uprobe_cpu_buffer = NULL; 763 } 764 } 765 766 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 767 { 768 struct uprobe_cpu_buffer *ucb; 769 int cpu; 770 771 cpu = raw_smp_processor_id(); 772 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 773 774 /* 775 * Use per-cpu buffers for fastest access, but we might migrate 776 * so the mutex makes sure we have sole access to it. 777 */ 778 mutex_lock(&ucb->mutex); 779 780 return ucb; 781 } 782 783 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 784 { 785 mutex_unlock(&ucb->mutex); 786 } 787 788 static void __uprobe_trace_func(struct trace_uprobe *tu, 789 unsigned long func, struct pt_regs *regs, 790 struct uprobe_cpu_buffer *ucb, int dsize, 791 struct trace_event_file *trace_file) 792 { 793 struct uprobe_trace_entry_head *entry; 794 struct ring_buffer_event *event; 795 struct ring_buffer *buffer; 796 void *data; 797 int size, esize; 798 struct trace_event_call *call = &tu->tp.call; 799 800 WARN_ON(call != trace_file->event_call); 801 802 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 803 return; 804 805 if (trace_trigger_soft_disabled(trace_file)) 806 return; 807 808 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 809 size = esize + tu->tp.size + dsize; 810 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 811 call->event.type, size, 0, 0); 812 if (!event) 813 return; 814 815 entry = ring_buffer_event_data(event); 816 if (is_ret_probe(tu)) { 817 entry->vaddr[0] = func; 818 entry->vaddr[1] = instruction_pointer(regs); 819 data = DATAOF_TRACE_ENTRY(entry, true); 820 } else { 821 entry->vaddr[0] = instruction_pointer(regs); 822 data = DATAOF_TRACE_ENTRY(entry, false); 823 } 824 825 memcpy(data, ucb->buf, tu->tp.size + dsize); 826 827 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); 828 } 829 830 /* uprobe handler */ 831 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 832 struct uprobe_cpu_buffer *ucb, int dsize) 833 { 834 struct event_file_link *link; 835 836 if (is_ret_probe(tu)) 837 return 0; 838 839 rcu_read_lock(); 840 list_for_each_entry_rcu(link, &tu->tp.files, list) 841 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 842 rcu_read_unlock(); 843 844 return 0; 845 } 846 847 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 848 struct pt_regs *regs, 849 struct uprobe_cpu_buffer *ucb, int dsize) 850 { 851 struct event_file_link *link; 852 853 rcu_read_lock(); 854 list_for_each_entry_rcu(link, &tu->tp.files, list) 855 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 856 rcu_read_unlock(); 857 } 858 859 /* Event entry printers */ 860 static enum print_line_t 861 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 862 { 863 struct uprobe_trace_entry_head *entry; 864 struct trace_seq *s = &iter->seq; 865 struct trace_uprobe *tu; 866 u8 *data; 867 int i; 868 869 entry = (struct uprobe_trace_entry_head *)iter->ent; 870 tu = container_of(event, struct trace_uprobe, tp.call.event); 871 872 if (is_ret_probe(tu)) { 873 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 874 trace_event_name(&tu->tp.call), 875 entry->vaddr[1], entry->vaddr[0]); 876 data = DATAOF_TRACE_ENTRY(entry, true); 877 } else { 878 trace_seq_printf(s, "%s: (0x%lx)", 879 trace_event_name(&tu->tp.call), 880 entry->vaddr[0]); 881 data = DATAOF_TRACE_ENTRY(entry, false); 882 } 883 884 for (i = 0; i < tu->tp.nr_args; i++) { 885 struct probe_arg *parg = &tu->tp.args[i]; 886 887 if (!parg->type->print(s, parg->name, data + parg->offset, entry)) 888 goto out; 889 } 890 891 trace_seq_putc(s, '\n'); 892 893 out: 894 return trace_handle_return(s); 895 } 896 897 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 898 enum uprobe_filter_ctx ctx, 899 struct mm_struct *mm); 900 901 static int 902 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, 903 filter_func_t filter) 904 { 905 bool enabled = trace_probe_is_enabled(&tu->tp); 906 struct event_file_link *link = NULL; 907 int ret; 908 909 if (file) { 910 if (tu->tp.flags & TP_FLAG_PROFILE) 911 return -EINTR; 912 913 link = kmalloc(sizeof(*link), GFP_KERNEL); 914 if (!link) 915 return -ENOMEM; 916 917 link->file = file; 918 list_add_tail_rcu(&link->list, &tu->tp.files); 919 920 tu->tp.flags |= TP_FLAG_TRACE; 921 } else { 922 if (tu->tp.flags & TP_FLAG_TRACE) 923 return -EINTR; 924 925 tu->tp.flags |= TP_FLAG_PROFILE; 926 } 927 928 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 929 930 if (enabled) 931 return 0; 932 933 ret = uprobe_buffer_enable(); 934 if (ret) 935 goto err_flags; 936 937 tu->consumer.filter = filter; 938 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 939 if (ret) 940 goto err_buffer; 941 942 return 0; 943 944 err_buffer: 945 uprobe_buffer_disable(); 946 947 err_flags: 948 if (file) { 949 list_del(&link->list); 950 kfree(link); 951 tu->tp.flags &= ~TP_FLAG_TRACE; 952 } else { 953 tu->tp.flags &= ~TP_FLAG_PROFILE; 954 } 955 return ret; 956 } 957 958 static void 959 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) 960 { 961 if (!trace_probe_is_enabled(&tu->tp)) 962 return; 963 964 if (file) { 965 struct event_file_link *link; 966 967 link = find_event_file_link(&tu->tp, file); 968 if (!link) 969 return; 970 971 list_del_rcu(&link->list); 972 /* synchronize with u{,ret}probe_trace_func */ 973 synchronize_sched(); 974 kfree(link); 975 976 if (!list_empty(&tu->tp.files)) 977 return; 978 } 979 980 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 981 982 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 983 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 984 985 uprobe_buffer_disable(); 986 } 987 988 static int uprobe_event_define_fields(struct trace_event_call *event_call) 989 { 990 int ret, i, size; 991 struct uprobe_trace_entry_head field; 992 struct trace_uprobe *tu = event_call->data; 993 994 if (is_ret_probe(tu)) { 995 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 996 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 997 size = SIZEOF_TRACE_ENTRY(true); 998 } else { 999 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 1000 size = SIZEOF_TRACE_ENTRY(false); 1001 } 1002 /* Set argument names as fields */ 1003 for (i = 0; i < tu->tp.nr_args; i++) { 1004 struct probe_arg *parg = &tu->tp.args[i]; 1005 1006 ret = trace_define_field(event_call, parg->type->fmttype, 1007 parg->name, size + parg->offset, 1008 parg->type->size, parg->type->is_signed, 1009 FILTER_OTHER); 1010 1011 if (ret) 1012 return ret; 1013 } 1014 return 0; 1015 } 1016 1017 #ifdef CONFIG_PERF_EVENTS 1018 static bool 1019 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1020 { 1021 struct perf_event *event; 1022 1023 if (filter->nr_systemwide) 1024 return true; 1025 1026 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1027 if (event->hw.target->mm == mm) 1028 return true; 1029 } 1030 1031 return false; 1032 } 1033 1034 static inline bool 1035 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1036 { 1037 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1038 } 1039 1040 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1041 { 1042 bool done; 1043 1044 write_lock(&tu->filter.rwlock); 1045 if (event->hw.target) { 1046 list_del(&event->hw.tp_list); 1047 done = tu->filter.nr_systemwide || 1048 (event->hw.target->flags & PF_EXITING) || 1049 uprobe_filter_event(tu, event); 1050 } else { 1051 tu->filter.nr_systemwide--; 1052 done = tu->filter.nr_systemwide; 1053 } 1054 write_unlock(&tu->filter.rwlock); 1055 1056 if (!done) 1057 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1058 1059 return 0; 1060 } 1061 1062 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1063 { 1064 bool done; 1065 int err; 1066 1067 write_lock(&tu->filter.rwlock); 1068 if (event->hw.target) { 1069 /* 1070 * event->parent != NULL means copy_process(), we can avoid 1071 * uprobe_apply(). current->mm must be probed and we can rely 1072 * on dup_mmap() which preserves the already installed bp's. 1073 * 1074 * attr.enable_on_exec means that exec/mmap will install the 1075 * breakpoints we need. 1076 */ 1077 done = tu->filter.nr_systemwide || 1078 event->parent || event->attr.enable_on_exec || 1079 uprobe_filter_event(tu, event); 1080 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1081 } else { 1082 done = tu->filter.nr_systemwide; 1083 tu->filter.nr_systemwide++; 1084 } 1085 write_unlock(&tu->filter.rwlock); 1086 1087 err = 0; 1088 if (!done) { 1089 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1090 if (err) 1091 uprobe_perf_close(tu, event); 1092 } 1093 return err; 1094 } 1095 1096 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1097 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1098 { 1099 struct trace_uprobe *tu; 1100 int ret; 1101 1102 tu = container_of(uc, struct trace_uprobe, consumer); 1103 read_lock(&tu->filter.rwlock); 1104 ret = __uprobe_perf_filter(&tu->filter, mm); 1105 read_unlock(&tu->filter.rwlock); 1106 1107 return ret; 1108 } 1109 1110 static void __uprobe_perf_func(struct trace_uprobe *tu, 1111 unsigned long func, struct pt_regs *regs, 1112 struct uprobe_cpu_buffer *ucb, int dsize) 1113 { 1114 struct trace_event_call *call = &tu->tp.call; 1115 struct uprobe_trace_entry_head *entry; 1116 struct hlist_head *head; 1117 void *data; 1118 int size, esize; 1119 int rctx; 1120 1121 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1122 return; 1123 1124 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1125 1126 size = esize + tu->tp.size + dsize; 1127 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1128 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1129 return; 1130 1131 preempt_disable(); 1132 head = this_cpu_ptr(call->perf_events); 1133 if (hlist_empty(head)) 1134 goto out; 1135 1136 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1137 if (!entry) 1138 goto out; 1139 1140 if (is_ret_probe(tu)) { 1141 entry->vaddr[0] = func; 1142 entry->vaddr[1] = instruction_pointer(regs); 1143 data = DATAOF_TRACE_ENTRY(entry, true); 1144 } else { 1145 entry->vaddr[0] = instruction_pointer(regs); 1146 data = DATAOF_TRACE_ENTRY(entry, false); 1147 } 1148 1149 memcpy(data, ucb->buf, tu->tp.size + dsize); 1150 1151 if (size - esize > tu->tp.size + dsize) { 1152 int len = tu->tp.size + dsize; 1153 1154 memset(data + len, 0, size - esize - len); 1155 } 1156 1157 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1158 head, NULL); 1159 out: 1160 preempt_enable(); 1161 } 1162 1163 /* uprobe profile handler */ 1164 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1165 struct uprobe_cpu_buffer *ucb, int dsize) 1166 { 1167 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1168 return UPROBE_HANDLER_REMOVE; 1169 1170 if (!is_ret_probe(tu)) 1171 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1172 return 0; 1173 } 1174 1175 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1176 struct pt_regs *regs, 1177 struct uprobe_cpu_buffer *ucb, int dsize) 1178 { 1179 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1180 } 1181 #endif /* CONFIG_PERF_EVENTS */ 1182 1183 static int 1184 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, 1185 void *data) 1186 { 1187 struct trace_uprobe *tu = event->data; 1188 struct trace_event_file *file = data; 1189 1190 switch (type) { 1191 case TRACE_REG_REGISTER: 1192 return probe_event_enable(tu, file, NULL); 1193 1194 case TRACE_REG_UNREGISTER: 1195 probe_event_disable(tu, file); 1196 return 0; 1197 1198 #ifdef CONFIG_PERF_EVENTS 1199 case TRACE_REG_PERF_REGISTER: 1200 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1201 1202 case TRACE_REG_PERF_UNREGISTER: 1203 probe_event_disable(tu, NULL); 1204 return 0; 1205 1206 case TRACE_REG_PERF_OPEN: 1207 return uprobe_perf_open(tu, data); 1208 1209 case TRACE_REG_PERF_CLOSE: 1210 return uprobe_perf_close(tu, data); 1211 1212 #endif 1213 default: 1214 return 0; 1215 } 1216 return 0; 1217 } 1218 1219 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1220 { 1221 struct trace_uprobe *tu; 1222 struct uprobe_dispatch_data udd; 1223 struct uprobe_cpu_buffer *ucb; 1224 int dsize, esize; 1225 int ret = 0; 1226 1227 1228 tu = container_of(con, struct trace_uprobe, consumer); 1229 tu->nhit++; 1230 1231 udd.tu = tu; 1232 udd.bp_addr = instruction_pointer(regs); 1233 1234 current->utask->vaddr = (unsigned long) &udd; 1235 1236 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1237 return 0; 1238 1239 dsize = __get_data_size(&tu->tp, regs); 1240 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1241 1242 ucb = uprobe_buffer_get(); 1243 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1244 1245 if (tu->tp.flags & TP_FLAG_TRACE) 1246 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1247 1248 #ifdef CONFIG_PERF_EVENTS 1249 if (tu->tp.flags & TP_FLAG_PROFILE) 1250 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1251 #endif 1252 uprobe_buffer_put(ucb); 1253 return ret; 1254 } 1255 1256 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1257 unsigned long func, struct pt_regs *regs) 1258 { 1259 struct trace_uprobe *tu; 1260 struct uprobe_dispatch_data udd; 1261 struct uprobe_cpu_buffer *ucb; 1262 int dsize, esize; 1263 1264 tu = container_of(con, struct trace_uprobe, consumer); 1265 1266 udd.tu = tu; 1267 udd.bp_addr = func; 1268 1269 current->utask->vaddr = (unsigned long) &udd; 1270 1271 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1272 return 0; 1273 1274 dsize = __get_data_size(&tu->tp, regs); 1275 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1276 1277 ucb = uprobe_buffer_get(); 1278 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1279 1280 if (tu->tp.flags & TP_FLAG_TRACE) 1281 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1282 1283 #ifdef CONFIG_PERF_EVENTS 1284 if (tu->tp.flags & TP_FLAG_PROFILE) 1285 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1286 #endif 1287 uprobe_buffer_put(ucb); 1288 return 0; 1289 } 1290 1291 static struct trace_event_functions uprobe_funcs = { 1292 .trace = print_uprobe_event 1293 }; 1294 1295 static int register_uprobe_event(struct trace_uprobe *tu) 1296 { 1297 struct trace_event_call *call = &tu->tp.call; 1298 int ret; 1299 1300 /* Initialize trace_event_call */ 1301 INIT_LIST_HEAD(&call->class->fields); 1302 call->event.funcs = &uprobe_funcs; 1303 call->class->define_fields = uprobe_event_define_fields; 1304 1305 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1306 return -ENOMEM; 1307 1308 ret = register_trace_event(&call->event); 1309 if (!ret) { 1310 kfree(call->print_fmt); 1311 return -ENODEV; 1312 } 1313 1314 call->flags = TRACE_EVENT_FL_UPROBE; 1315 call->class->reg = trace_uprobe_register; 1316 call->data = tu; 1317 ret = trace_add_event_call(call); 1318 1319 if (ret) { 1320 pr_info("Failed to register uprobe event: %s\n", 1321 trace_event_name(call)); 1322 kfree(call->print_fmt); 1323 unregister_trace_event(&call->event); 1324 } 1325 1326 return ret; 1327 } 1328 1329 static int unregister_uprobe_event(struct trace_uprobe *tu) 1330 { 1331 int ret; 1332 1333 /* tu->event is unregistered in trace_remove_event_call() */ 1334 ret = trace_remove_event_call(&tu->tp.call); 1335 if (ret) 1336 return ret; 1337 kfree(tu->tp.call.print_fmt); 1338 tu->tp.call.print_fmt = NULL; 1339 return 0; 1340 } 1341 1342 /* Make a trace interface for controling probe points */ 1343 static __init int init_uprobe_trace(void) 1344 { 1345 struct dentry *d_tracer; 1346 1347 d_tracer = tracing_init_dentry(); 1348 if (IS_ERR(d_tracer)) 1349 return 0; 1350 1351 trace_create_file("uprobe_events", 0644, d_tracer, 1352 NULL, &uprobe_events_ops); 1353 /* Profile interface */ 1354 trace_create_file("uprobe_profile", 0444, d_tracer, 1355 NULL, &uprobe_profile_ops); 1356 return 0; 1357 } 1358 1359 fs_initcall(init_uprobe_trace); 1360