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 31struct 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 43struct 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 */ 52struct 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 67static int register_uprobe_event(struct trace_uprobe *tu); 68static int unregister_uprobe_event(struct trace_uprobe *tu); 69 70static DEFINE_MUTEX(uprobe_lock); 71static LIST_HEAD(uprobe_list); 72 73struct uprobe_dispatch_data { 74 struct trace_uprobe *tu; 75 unsigned long bp_addr; 76}; 77 78static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); 79static int uretprobe_dispatcher(struct uprobe_consumer *con, 80 unsigned long func, struct pt_regs *regs); 81 82#ifdef CONFIG_STACK_GROWSUP 83static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 84{ 85 return addr - (n * sizeof(long)); 86} 87#else 88static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 89{ 90 return addr + (n * sizeof(long)); 91} 92#endif 93 94static 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) \ 111static 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} 117DEFINE_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) \ 123static 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} 134DEFINE_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 */ 139static 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 161static 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 175static 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) \ 187static 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} 194DEFINE_BASIC_FETCH_FUNCS(file_offset) 195DEFINE_FETCH_file_offset(string) 196DEFINE_FETCH_file_offset(string_size) 197 198/* Fetch type information table */ 199static 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 218static 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 225static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 226{ 227 return !filter->nr_systemwide && list_empty(&filter->perf_events); 228} 229 230static 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 */ 238static struct trace_uprobe * 239alloc_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 270error: 271 kfree(tu->tp.call.name); 272 kfree(tu); 273 274 return ERR_PTR(-ENOMEM); 275} 276 277static 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 291static 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 */ 304static 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 */ 318static 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 343end: 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 */ 355static int create_trace_uprobe(int argc, char **argv) 356{ 357 struct trace_uprobe *tu; 358 struct inode *inode; 359 char *arg, *event, *group, *filename; 360 char buf[MAX_EVENT_NAME_LEN]; 361 struct path path; 362 unsigned long offset; 363 bool is_delete, is_return; 364 int i, ret; 365 366 inode = NULL; 367 ret = 0; 368 is_delete = false; 369 is_return = false; 370 event = NULL; 371 group = NULL; 372 373 /* argc must be >= 1 */ 374 if (argv[0][0] == '-') 375 is_delete = true; 376 else if (argv[0][0] == 'r') 377 is_return = true; 378 else if (argv[0][0] != 'p') { 379 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n"); 380 return -EINVAL; 381 } 382 383 if (argv[0][1] == ':') { 384 event = &argv[0][2]; 385 arg = strchr(event, '/'); 386 387 if (arg) { 388 group = event; 389 event = arg + 1; 390 event[-1] = '\0'; 391 392 if (strlen(group) == 0) { 393 pr_info("Group name is not specified\n"); 394 return -EINVAL; 395 } 396 } 397 if (strlen(event) == 0) { 398 pr_info("Event name is not specified\n"); 399 return -EINVAL; 400 } 401 } 402 if (!group) 403 group = UPROBE_EVENT_SYSTEM; 404 405 if (is_delete) { 406 int ret; 407 408 if (!event) { 409 pr_info("Delete command needs an event name.\n"); 410 return -EINVAL; 411 } 412 mutex_lock(&uprobe_lock); 413 tu = find_probe_event(event, group); 414 415 if (!tu) { 416 mutex_unlock(&uprobe_lock); 417 pr_info("Event %s/%s doesn't exist.\n", group, event); 418 return -ENOENT; 419 } 420 /* delete an event */ 421 ret = unregister_trace_uprobe(tu); 422 mutex_unlock(&uprobe_lock); 423 return ret; 424 } 425 426 if (argc < 2) { 427 pr_info("Probe point is not specified.\n"); 428 return -EINVAL; 429 } 430 if (isdigit(argv[1][0])) { 431 pr_info("probe point must be have a filename.\n"); 432 return -EINVAL; 433 } 434 arg = strchr(argv[1], ':'); 435 if (!arg) { 436 ret = -EINVAL; 437 goto fail_address_parse; 438 } 439 440 *arg++ = '\0'; 441 filename = argv[1]; 442 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 443 if (ret) 444 goto fail_address_parse; 445 446 inode = igrab(d_inode(path.dentry)); 447 path_put(&path); 448 449 if (!inode || !S_ISREG(inode->i_mode)) { 450 ret = -EINVAL; 451 goto fail_address_parse; 452 } 453 454 ret = kstrtoul(arg, 0, &offset); 455 if (ret) 456 goto fail_address_parse; 457 458 argc -= 2; 459 argv += 2; 460 461 /* setup a probe */ 462 if (!event) { 463 char *tail; 464 char *ptr; 465 466 tail = kstrdup(kbasename(filename), GFP_KERNEL); 467 if (!tail) { 468 ret = -ENOMEM; 469 goto fail_address_parse; 470 } 471 472 ptr = strpbrk(tail, ".-_"); 473 if (ptr) 474 *ptr = '\0'; 475 476 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 477 event = buf; 478 kfree(tail); 479 } 480 481 tu = alloc_trace_uprobe(group, event, argc, is_return); 482 if (IS_ERR(tu)) { 483 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); 484 ret = PTR_ERR(tu); 485 goto fail_address_parse; 486 } 487 tu->offset = offset; 488 tu->inode = inode; 489 tu->filename = kstrdup(filename, GFP_KERNEL); 490 491 if (!tu->filename) { 492 pr_info("Failed to allocate filename.\n"); 493 ret = -ENOMEM; 494 goto error; 495 } 496 497 /* parse arguments */ 498 ret = 0; 499 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 500 struct probe_arg *parg = &tu->tp.args[i]; 501 502 /* Increment count for freeing args in error case */ 503 tu->tp.nr_args++; 504 505 /* Parse argument name */ 506 arg = strchr(argv[i], '='); 507 if (arg) { 508 *arg++ = '\0'; 509 parg->name = kstrdup(argv[i], GFP_KERNEL); 510 } else { 511 arg = argv[i]; 512 /* If argument name is omitted, set "argN" */ 513 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); 514 parg->name = kstrdup(buf, GFP_KERNEL); 515 } 516 517 if (!parg->name) { 518 pr_info("Failed to allocate argument[%d] name.\n", i); 519 ret = -ENOMEM; 520 goto error; 521 } 522 523 if (!is_good_name(parg->name)) { 524 pr_info("Invalid argument[%d] name: %s\n", i, parg->name); 525 ret = -EINVAL; 526 goto error; 527 } 528 529 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) { 530 pr_info("Argument[%d] name '%s' conflicts with " 531 "another field.\n", i, argv[i]); 532 ret = -EINVAL; 533 goto error; 534 } 535 536 /* Parse fetch argument */ 537 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg, 538 is_return, false, 539 uprobes_fetch_type_table); 540 if (ret) { 541 pr_info("Parse error at argument[%d]. (%d)\n", i, ret); 542 goto error; 543 } 544 } 545 546 ret = register_trace_uprobe(tu); 547 if (ret) 548 goto error; 549 return 0; 550 551error: 552 free_trace_uprobe(tu); 553 return ret; 554 555fail_address_parse: 556 iput(inode); 557 558 pr_info("Failed to parse address or file.\n"); 559 560 return ret; 561} 562 563static int cleanup_all_probes(void) 564{ 565 struct trace_uprobe *tu; 566 int ret = 0; 567 568 mutex_lock(&uprobe_lock); 569 while (!list_empty(&uprobe_list)) { 570 tu = list_entry(uprobe_list.next, struct trace_uprobe, list); 571 ret = unregister_trace_uprobe(tu); 572 if (ret) 573 break; 574 } 575 mutex_unlock(&uprobe_lock); 576 return ret; 577} 578 579/* Probes listing interfaces */ 580static void *probes_seq_start(struct seq_file *m, loff_t *pos) 581{ 582 mutex_lock(&uprobe_lock); 583 return seq_list_start(&uprobe_list, *pos); 584} 585 586static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) 587{ 588 return seq_list_next(v, &uprobe_list, pos); 589} 590 591static void probes_seq_stop(struct seq_file *m, void *v) 592{ 593 mutex_unlock(&uprobe_lock); 594} 595 596static int probes_seq_show(struct seq_file *m, void *v) 597{ 598 struct trace_uprobe *tu = v; 599 char c = is_ret_probe(tu) ? 'r' : 'p'; 600 int i; 601 602 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system, 603 ftrace_event_name(&tu->tp.call)); 604 seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset); 605 606 for (i = 0; i < tu->tp.nr_args; i++) 607 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 608 609 seq_putc(m, '\n'); 610 return 0; 611} 612 613static const struct seq_operations probes_seq_op = { 614 .start = probes_seq_start, 615 .next = probes_seq_next, 616 .stop = probes_seq_stop, 617 .show = probes_seq_show 618}; 619 620static int probes_open(struct inode *inode, struct file *file) 621{ 622 int ret; 623 624 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 625 ret = cleanup_all_probes(); 626 if (ret) 627 return ret; 628 } 629 630 return seq_open(file, &probes_seq_op); 631} 632 633static ssize_t probes_write(struct file *file, const char __user *buffer, 634 size_t count, loff_t *ppos) 635{ 636 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); 637} 638 639static const struct file_operations uprobe_events_ops = { 640 .owner = THIS_MODULE, 641 .open = probes_open, 642 .read = seq_read, 643 .llseek = seq_lseek, 644 .release = seq_release, 645 .write = probes_write, 646}; 647 648/* Probes profiling interfaces */ 649static int probes_profile_seq_show(struct seq_file *m, void *v) 650{ 651 struct trace_uprobe *tu = v; 652 653 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 654 ftrace_event_name(&tu->tp.call), tu->nhit); 655 return 0; 656} 657 658static const struct seq_operations profile_seq_op = { 659 .start = probes_seq_start, 660 .next = probes_seq_next, 661 .stop = probes_seq_stop, 662 .show = probes_profile_seq_show 663}; 664 665static int profile_open(struct inode *inode, struct file *file) 666{ 667 return seq_open(file, &profile_seq_op); 668} 669 670static const struct file_operations uprobe_profile_ops = { 671 .owner = THIS_MODULE, 672 .open = profile_open, 673 .read = seq_read, 674 .llseek = seq_lseek, 675 .release = seq_release, 676}; 677 678struct uprobe_cpu_buffer { 679 struct mutex mutex; 680 void *buf; 681}; 682static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 683static int uprobe_buffer_refcnt; 684 685static int uprobe_buffer_init(void) 686{ 687 int cpu, err_cpu; 688 689 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 690 if (uprobe_cpu_buffer == NULL) 691 return -ENOMEM; 692 693 for_each_possible_cpu(cpu) { 694 struct page *p = alloc_pages_node(cpu_to_node(cpu), 695 GFP_KERNEL, 0); 696 if (p == NULL) { 697 err_cpu = cpu; 698 goto err; 699 } 700 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 701 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 702 } 703 704 return 0; 705 706err: 707 for_each_possible_cpu(cpu) { 708 if (cpu == err_cpu) 709 break; 710 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 711 } 712 713 free_percpu(uprobe_cpu_buffer); 714 return -ENOMEM; 715} 716 717static int uprobe_buffer_enable(void) 718{ 719 int ret = 0; 720 721 BUG_ON(!mutex_is_locked(&event_mutex)); 722 723 if (uprobe_buffer_refcnt++ == 0) { 724 ret = uprobe_buffer_init(); 725 if (ret < 0) 726 uprobe_buffer_refcnt--; 727 } 728 729 return ret; 730} 731 732static void uprobe_buffer_disable(void) 733{ 734 int cpu; 735 736 BUG_ON(!mutex_is_locked(&event_mutex)); 737 738 if (--uprobe_buffer_refcnt == 0) { 739 for_each_possible_cpu(cpu) 740 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 741 cpu)->buf); 742 743 free_percpu(uprobe_cpu_buffer); 744 uprobe_cpu_buffer = NULL; 745 } 746} 747 748static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 749{ 750 struct uprobe_cpu_buffer *ucb; 751 int cpu; 752 753 cpu = raw_smp_processor_id(); 754 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 755 756 /* 757 * Use per-cpu buffers for fastest access, but we might migrate 758 * so the mutex makes sure we have sole access to it. 759 */ 760 mutex_lock(&ucb->mutex); 761 762 return ucb; 763} 764 765static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 766{ 767 mutex_unlock(&ucb->mutex); 768} 769 770static void __uprobe_trace_func(struct trace_uprobe *tu, 771 unsigned long func, struct pt_regs *regs, 772 struct uprobe_cpu_buffer *ucb, int dsize, 773 struct ftrace_event_file *ftrace_file) 774{ 775 struct uprobe_trace_entry_head *entry; 776 struct ring_buffer_event *event; 777 struct ring_buffer *buffer; 778 void *data; 779 int size, esize; 780 struct ftrace_event_call *call = &tu->tp.call; 781 782 WARN_ON(call != ftrace_file->event_call); 783 784 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 785 return; 786 787 if (ftrace_trigger_soft_disabled(ftrace_file)) 788 return; 789 790 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 791 size = esize + tu->tp.size + dsize; 792 event = trace_event_buffer_lock_reserve(&buffer, ftrace_file, 793 call->event.type, size, 0, 0); 794 if (!event) 795 return; 796 797 entry = ring_buffer_event_data(event); 798 if (is_ret_probe(tu)) { 799 entry->vaddr[0] = func; 800 entry->vaddr[1] = instruction_pointer(regs); 801 data = DATAOF_TRACE_ENTRY(entry, true); 802 } else { 803 entry->vaddr[0] = instruction_pointer(regs); 804 data = DATAOF_TRACE_ENTRY(entry, false); 805 } 806 807 memcpy(data, ucb->buf, tu->tp.size + dsize); 808 809 event_trigger_unlock_commit(ftrace_file, buffer, event, entry, 0, 0); 810} 811 812/* uprobe handler */ 813static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 814 struct uprobe_cpu_buffer *ucb, int dsize) 815{ 816 struct event_file_link *link; 817 818 if (is_ret_probe(tu)) 819 return 0; 820 821 rcu_read_lock(); 822 list_for_each_entry_rcu(link, &tu->tp.files, list) 823 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 824 rcu_read_unlock(); 825 826 return 0; 827} 828 829static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 830 struct pt_regs *regs, 831 struct uprobe_cpu_buffer *ucb, int dsize) 832{ 833 struct event_file_link *link; 834 835 rcu_read_lock(); 836 list_for_each_entry_rcu(link, &tu->tp.files, list) 837 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 838 rcu_read_unlock(); 839} 840 841/* Event entry printers */ 842static enum print_line_t 843print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 844{ 845 struct uprobe_trace_entry_head *entry; 846 struct trace_seq *s = &iter->seq; 847 struct trace_uprobe *tu; 848 u8 *data; 849 int i; 850 851 entry = (struct uprobe_trace_entry_head *)iter->ent; 852 tu = container_of(event, struct trace_uprobe, tp.call.event); 853 854 if (is_ret_probe(tu)) { 855 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 856 ftrace_event_name(&tu->tp.call), 857 entry->vaddr[1], entry->vaddr[0]); 858 data = DATAOF_TRACE_ENTRY(entry, true); 859 } else { 860 trace_seq_printf(s, "%s: (0x%lx)", 861 ftrace_event_name(&tu->tp.call), 862 entry->vaddr[0]); 863 data = DATAOF_TRACE_ENTRY(entry, false); 864 } 865 866 for (i = 0; i < tu->tp.nr_args; i++) { 867 struct probe_arg *parg = &tu->tp.args[i]; 868 869 if (!parg->type->print(s, parg->name, data + parg->offset, entry)) 870 goto out; 871 } 872 873 trace_seq_putc(s, '\n'); 874 875 out: 876 return trace_handle_return(s); 877} 878 879typedef bool (*filter_func_t)(struct uprobe_consumer *self, 880 enum uprobe_filter_ctx ctx, 881 struct mm_struct *mm); 882 883static int 884probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file, 885 filter_func_t filter) 886{ 887 bool enabled = trace_probe_is_enabled(&tu->tp); 888 struct event_file_link *link = NULL; 889 int ret; 890 891 if (file) { 892 if (tu->tp.flags & TP_FLAG_PROFILE) 893 return -EINTR; 894 895 link = kmalloc(sizeof(*link), GFP_KERNEL); 896 if (!link) 897 return -ENOMEM; 898 899 link->file = file; 900 list_add_tail_rcu(&link->list, &tu->tp.files); 901 902 tu->tp.flags |= TP_FLAG_TRACE; 903 } else { 904 if (tu->tp.flags & TP_FLAG_TRACE) 905 return -EINTR; 906 907 tu->tp.flags |= TP_FLAG_PROFILE; 908 } 909 910 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 911 912 if (enabled) 913 return 0; 914 915 ret = uprobe_buffer_enable(); 916 if (ret) 917 goto err_flags; 918 919 tu->consumer.filter = filter; 920 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 921 if (ret) 922 goto err_buffer; 923 924 return 0; 925 926 err_buffer: 927 uprobe_buffer_disable(); 928 929 err_flags: 930 if (file) { 931 list_del(&link->list); 932 kfree(link); 933 tu->tp.flags &= ~TP_FLAG_TRACE; 934 } else { 935 tu->tp.flags &= ~TP_FLAG_PROFILE; 936 } 937 return ret; 938} 939 940static void 941probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file) 942{ 943 if (!trace_probe_is_enabled(&tu->tp)) 944 return; 945 946 if (file) { 947 struct event_file_link *link; 948 949 link = find_event_file_link(&tu->tp, file); 950 if (!link) 951 return; 952 953 list_del_rcu(&link->list); 954 /* synchronize with u{,ret}probe_trace_func */ 955 synchronize_sched(); 956 kfree(link); 957 958 if (!list_empty(&tu->tp.files)) 959 return; 960 } 961 962 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 963 964 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 965 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 966 967 uprobe_buffer_disable(); 968} 969 970static int uprobe_event_define_fields(struct ftrace_event_call *event_call) 971{ 972 int ret, i, size; 973 struct uprobe_trace_entry_head field; 974 struct trace_uprobe *tu = event_call->data; 975 976 if (is_ret_probe(tu)) { 977 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 978 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 979 size = SIZEOF_TRACE_ENTRY(true); 980 } else { 981 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 982 size = SIZEOF_TRACE_ENTRY(false); 983 } 984 /* Set argument names as fields */ 985 for (i = 0; i < tu->tp.nr_args; i++) { 986 struct probe_arg *parg = &tu->tp.args[i]; 987 988 ret = trace_define_field(event_call, parg->type->fmttype, 989 parg->name, size + parg->offset, 990 parg->type->size, parg->type->is_signed, 991 FILTER_OTHER); 992 993 if (ret) 994 return ret; 995 } 996 return 0; 997} 998 999#ifdef CONFIG_PERF_EVENTS 1000static bool 1001__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1002{ 1003 struct perf_event *event; 1004 1005 if (filter->nr_systemwide) 1006 return true; 1007 1008 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1009 if (event->hw.target->mm == mm) 1010 return true; 1011 } 1012 1013 return false; 1014} 1015 1016static inline bool 1017uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1018{ 1019 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1020} 1021 1022static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1023{ 1024 bool done; 1025 1026 write_lock(&tu->filter.rwlock); 1027 if (event->hw.target) { 1028 list_del(&event->hw.tp_list); 1029 done = tu->filter.nr_systemwide || 1030 (event->hw.target->flags & PF_EXITING) || 1031 uprobe_filter_event(tu, event); 1032 } else { 1033 tu->filter.nr_systemwide--; 1034 done = tu->filter.nr_systemwide; 1035 } 1036 write_unlock(&tu->filter.rwlock); 1037 1038 if (!done) 1039 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1040 1041 return 0; 1042} 1043 1044static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1045{ 1046 bool done; 1047 int err; 1048 1049 write_lock(&tu->filter.rwlock); 1050 if (event->hw.target) { 1051 /* 1052 * event->parent != NULL means copy_process(), we can avoid 1053 * uprobe_apply(). current->mm must be probed and we can rely 1054 * on dup_mmap() which preserves the already installed bp's. 1055 * 1056 * attr.enable_on_exec means that exec/mmap will install the 1057 * breakpoints we need. 1058 */ 1059 done = tu->filter.nr_systemwide || 1060 event->parent || event->attr.enable_on_exec || 1061 uprobe_filter_event(tu, event); 1062 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1063 } else { 1064 done = tu->filter.nr_systemwide; 1065 tu->filter.nr_systemwide++; 1066 } 1067 write_unlock(&tu->filter.rwlock); 1068 1069 err = 0; 1070 if (!done) { 1071 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1072 if (err) 1073 uprobe_perf_close(tu, event); 1074 } 1075 return err; 1076} 1077 1078static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1079 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1080{ 1081 struct trace_uprobe *tu; 1082 int ret; 1083 1084 tu = container_of(uc, struct trace_uprobe, consumer); 1085 read_lock(&tu->filter.rwlock); 1086 ret = __uprobe_perf_filter(&tu->filter, mm); 1087 read_unlock(&tu->filter.rwlock); 1088 1089 return ret; 1090} 1091 1092static void __uprobe_perf_func(struct trace_uprobe *tu, 1093 unsigned long func, struct pt_regs *regs, 1094 struct uprobe_cpu_buffer *ucb, int dsize) 1095{ 1096 struct ftrace_event_call *call = &tu->tp.call; 1097 struct uprobe_trace_entry_head *entry; 1098 struct hlist_head *head; 1099 void *data; 1100 int size, esize; 1101 int rctx; 1102 1103 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1104 1105 size = esize + tu->tp.size + dsize; 1106 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1107 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1108 return; 1109 1110 preempt_disable(); 1111 head = this_cpu_ptr(call->perf_events); 1112 if (hlist_empty(head)) 1113 goto out; 1114 1115 entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx); 1116 if (!entry) 1117 goto out; 1118 1119 if (is_ret_probe(tu)) { 1120 entry->vaddr[0] = func; 1121 entry->vaddr[1] = instruction_pointer(regs); 1122 data = DATAOF_TRACE_ENTRY(entry, true); 1123 } else { 1124 entry->vaddr[0] = instruction_pointer(regs); 1125 data = DATAOF_TRACE_ENTRY(entry, false); 1126 } 1127 1128 memcpy(data, ucb->buf, tu->tp.size + dsize); 1129 1130 if (size - esize > tu->tp.size + dsize) { 1131 int len = tu->tp.size + dsize; 1132 1133 memset(data + len, 0, size - esize - len); 1134 } 1135 1136 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL); 1137 out: 1138 preempt_enable(); 1139} 1140 1141/* uprobe profile handler */ 1142static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1143 struct uprobe_cpu_buffer *ucb, int dsize) 1144{ 1145 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1146 return UPROBE_HANDLER_REMOVE; 1147 1148 if (!is_ret_probe(tu)) 1149 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1150 return 0; 1151} 1152 1153static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1154 struct pt_regs *regs, 1155 struct uprobe_cpu_buffer *ucb, int dsize) 1156{ 1157 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1158} 1159#endif /* CONFIG_PERF_EVENTS */ 1160 1161static int 1162trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, 1163 void *data) 1164{ 1165 struct trace_uprobe *tu = event->data; 1166 struct ftrace_event_file *file = data; 1167 1168 switch (type) { 1169 case TRACE_REG_REGISTER: 1170 return probe_event_enable(tu, file, NULL); 1171 1172 case TRACE_REG_UNREGISTER: 1173 probe_event_disable(tu, file); 1174 return 0; 1175 1176#ifdef CONFIG_PERF_EVENTS 1177 case TRACE_REG_PERF_REGISTER: 1178 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1179 1180 case TRACE_REG_PERF_UNREGISTER: 1181 probe_event_disable(tu, NULL); 1182 return 0; 1183 1184 case TRACE_REG_PERF_OPEN: 1185 return uprobe_perf_open(tu, data); 1186 1187 case TRACE_REG_PERF_CLOSE: 1188 return uprobe_perf_close(tu, data); 1189 1190#endif 1191 default: 1192 return 0; 1193 } 1194 return 0; 1195} 1196 1197static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1198{ 1199 struct trace_uprobe *tu; 1200 struct uprobe_dispatch_data udd; 1201 struct uprobe_cpu_buffer *ucb; 1202 int dsize, esize; 1203 int ret = 0; 1204 1205 1206 tu = container_of(con, struct trace_uprobe, consumer); 1207 tu->nhit++; 1208 1209 udd.tu = tu; 1210 udd.bp_addr = instruction_pointer(regs); 1211 1212 current->utask->vaddr = (unsigned long) &udd; 1213 1214 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1215 return 0; 1216 1217 dsize = __get_data_size(&tu->tp, regs); 1218 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1219 1220 ucb = uprobe_buffer_get(); 1221 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1222 1223 if (tu->tp.flags & TP_FLAG_TRACE) 1224 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1225 1226#ifdef CONFIG_PERF_EVENTS 1227 if (tu->tp.flags & TP_FLAG_PROFILE) 1228 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1229#endif 1230 uprobe_buffer_put(ucb); 1231 return ret; 1232} 1233 1234static int uretprobe_dispatcher(struct uprobe_consumer *con, 1235 unsigned long func, struct pt_regs *regs) 1236{ 1237 struct trace_uprobe *tu; 1238 struct uprobe_dispatch_data udd; 1239 struct uprobe_cpu_buffer *ucb; 1240 int dsize, esize; 1241 1242 tu = container_of(con, struct trace_uprobe, consumer); 1243 1244 udd.tu = tu; 1245 udd.bp_addr = func; 1246 1247 current->utask->vaddr = (unsigned long) &udd; 1248 1249 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1250 return 0; 1251 1252 dsize = __get_data_size(&tu->tp, regs); 1253 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1254 1255 ucb = uprobe_buffer_get(); 1256 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); 1257 1258 if (tu->tp.flags & TP_FLAG_TRACE) 1259 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1260 1261#ifdef CONFIG_PERF_EVENTS 1262 if (tu->tp.flags & TP_FLAG_PROFILE) 1263 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1264#endif 1265 uprobe_buffer_put(ucb); 1266 return 0; 1267} 1268 1269static struct trace_event_functions uprobe_funcs = { 1270 .trace = print_uprobe_event 1271}; 1272 1273static int register_uprobe_event(struct trace_uprobe *tu) 1274{ 1275 struct ftrace_event_call *call = &tu->tp.call; 1276 int ret; 1277 1278 /* Initialize ftrace_event_call */ 1279 INIT_LIST_HEAD(&call->class->fields); 1280 call->event.funcs = &uprobe_funcs; 1281 call->class->define_fields = uprobe_event_define_fields; 1282 1283 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1284 return -ENOMEM; 1285 1286 ret = register_ftrace_event(&call->event); 1287 if (!ret) { 1288 kfree(call->print_fmt); 1289 return -ENODEV; 1290 } 1291 1292 call->class->reg = trace_uprobe_register; 1293 call->data = tu; 1294 ret = trace_add_event_call(call); 1295 1296 if (ret) { 1297 pr_info("Failed to register uprobe event: %s\n", 1298 ftrace_event_name(call)); 1299 kfree(call->print_fmt); 1300 unregister_ftrace_event(&call->event); 1301 } 1302 1303 return ret; 1304} 1305 1306static int unregister_uprobe_event(struct trace_uprobe *tu) 1307{ 1308 int ret; 1309 1310 /* tu->event is unregistered in trace_remove_event_call() */ 1311 ret = trace_remove_event_call(&tu->tp.call); 1312 if (ret) 1313 return ret; 1314 kfree(tu->tp.call.print_fmt); 1315 tu->tp.call.print_fmt = NULL; 1316 return 0; 1317} 1318 1319/* Make a trace interface for controling probe points */ 1320static __init int init_uprobe_trace(void) 1321{ 1322 struct dentry *d_tracer; 1323 1324 d_tracer = tracing_init_dentry(); 1325 if (IS_ERR(d_tracer)) 1326 return 0; 1327 1328 trace_create_file("uprobe_events", 0644, d_tracer, 1329 NULL, &uprobe_events_ops); 1330 /* Profile interface */ 1331 trace_create_file("uprobe_profile", 0444, d_tracer, 1332 NULL, &uprobe_profile_ops); 1333 return 0; 1334} 1335 1336fs_initcall(init_uprobe_trace); 1337