kprobes.c revision 4a2bb6fcc80e6330ca2f2393e98605052cc7780b
1/* 2 * Kernel Probes (KProbes) 3 * kernel/kprobes.c 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 18 * 19 * Copyright (C) IBM Corporation, 2002, 2004 20 * 21 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel 22 * Probes initial implementation (includes suggestions from 23 * Rusty Russell). 24 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with 25 * hlists and exceptions notifier as suggested by Andi Kleen. 26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes 27 * interface to access function arguments. 28 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes 29 * exceptions notifier to be first on the priority list. 30 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston 31 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi 32 * <prasanna@in.ibm.com> added function-return probes. 33 */ 34#include <linux/kprobes.h> 35#include <linux/hash.h> 36#include <linux/init.h> 37#include <linux/slab.h> 38#include <linux/stddef.h> 39#include <linux/module.h> 40#include <linux/moduleloader.h> 41#include <linux/kallsyms.h> 42#include <linux/freezer.h> 43#include <linux/seq_file.h> 44#include <linux/debugfs.h> 45#include <linux/kdebug.h> 46#include <linux/memory.h> 47 48#include <asm-generic/sections.h> 49#include <asm/cacheflush.h> 50#include <asm/errno.h> 51#include <asm/uaccess.h> 52 53#define KPROBE_HASH_BITS 6 54#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) 55 56 57/* 58 * Some oddball architectures like 64bit powerpc have function descriptors 59 * so this must be overridable. 60 */ 61#ifndef kprobe_lookup_name 62#define kprobe_lookup_name(name, addr) \ 63 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) 64#endif 65 66static int kprobes_initialized; 67static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; 68static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; 69 70/* NOTE: change this value only with kprobe_mutex held */ 71static bool kprobes_all_disarmed; 72 73static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ 74static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; 75static struct { 76 spinlock_t lock ____cacheline_aligned_in_smp; 77} kretprobe_table_locks[KPROBE_TABLE_SIZE]; 78 79static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) 80{ 81 return &(kretprobe_table_locks[hash].lock); 82} 83 84/* 85 * Normally, functions that we'd want to prohibit kprobes in, are marked 86 * __kprobes. But, there are cases where such functions already belong to 87 * a different section (__sched for preempt_schedule) 88 * 89 * For such cases, we now have a blacklist 90 */ 91static struct kprobe_blackpoint kprobe_blacklist[] = { 92 {"preempt_schedule",}, 93 {NULL} /* Terminator */ 94}; 95 96#ifdef __ARCH_WANT_KPROBES_INSN_SLOT 97/* 98 * kprobe->ainsn.insn points to the copy of the instruction to be 99 * single-stepped. x86_64, POWER4 and above have no-exec support and 100 * stepping on the instruction on a vmalloced/kmalloced/data page 101 * is a recipe for disaster 102 */ 103#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) 104 105struct kprobe_insn_page { 106 struct hlist_node hlist; 107 kprobe_opcode_t *insns; /* Page of instruction slots */ 108 char slot_used[INSNS_PER_PAGE]; 109 int nused; 110 int ngarbage; 111}; 112 113enum kprobe_slot_state { 114 SLOT_CLEAN = 0, 115 SLOT_DIRTY = 1, 116 SLOT_USED = 2, 117}; 118 119static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */ 120static struct hlist_head kprobe_insn_pages; 121static int kprobe_garbage_slots; 122static int collect_garbage_slots(void); 123 124static int __kprobes check_safety(void) 125{ 126 int ret = 0; 127#if defined(CONFIG_PREEMPT) && defined(CONFIG_FREEZER) 128 ret = freeze_processes(); 129 if (ret == 0) { 130 struct task_struct *p, *q; 131 do_each_thread(p, q) { 132 if (p != current && p->state == TASK_RUNNING && 133 p->pid != 0) { 134 printk("Check failed: %s is running\n",p->comm); 135 ret = -1; 136 goto loop_end; 137 } 138 } while_each_thread(p, q); 139 } 140loop_end: 141 thaw_processes(); 142#else 143 synchronize_sched(); 144#endif 145 return ret; 146} 147 148/** 149 * __get_insn_slot() - Find a slot on an executable page for an instruction. 150 * We allocate an executable page if there's no room on existing ones. 151 */ 152static kprobe_opcode_t __kprobes *__get_insn_slot(void) 153{ 154 struct kprobe_insn_page *kip; 155 struct hlist_node *pos; 156 157 retry: 158 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { 159 if (kip->nused < INSNS_PER_PAGE) { 160 int i; 161 for (i = 0; i < INSNS_PER_PAGE; i++) { 162 if (kip->slot_used[i] == SLOT_CLEAN) { 163 kip->slot_used[i] = SLOT_USED; 164 kip->nused++; 165 return kip->insns + (i * MAX_INSN_SIZE); 166 } 167 } 168 /* Surprise! No unused slots. Fix kip->nused. */ 169 kip->nused = INSNS_PER_PAGE; 170 } 171 } 172 173 /* If there are any garbage slots, collect it and try again. */ 174 if (kprobe_garbage_slots && collect_garbage_slots() == 0) { 175 goto retry; 176 } 177 /* All out of space. Need to allocate a new page. Use slot 0. */ 178 kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); 179 if (!kip) 180 return NULL; 181 182 /* 183 * Use module_alloc so this page is within +/- 2GB of where the 184 * kernel image and loaded module images reside. This is required 185 * so x86_64 can correctly handle the %rip-relative fixups. 186 */ 187 kip->insns = module_alloc(PAGE_SIZE); 188 if (!kip->insns) { 189 kfree(kip); 190 return NULL; 191 } 192 INIT_HLIST_NODE(&kip->hlist); 193 hlist_add_head(&kip->hlist, &kprobe_insn_pages); 194 memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE); 195 kip->slot_used[0] = SLOT_USED; 196 kip->nused = 1; 197 kip->ngarbage = 0; 198 return kip->insns; 199} 200 201kprobe_opcode_t __kprobes *get_insn_slot(void) 202{ 203 kprobe_opcode_t *ret; 204 mutex_lock(&kprobe_insn_mutex); 205 ret = __get_insn_slot(); 206 mutex_unlock(&kprobe_insn_mutex); 207 return ret; 208} 209 210/* Return 1 if all garbages are collected, otherwise 0. */ 211static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) 212{ 213 kip->slot_used[idx] = SLOT_CLEAN; 214 kip->nused--; 215 if (kip->nused == 0) { 216 /* 217 * Page is no longer in use. Free it unless 218 * it's the last one. We keep the last one 219 * so as not to have to set it up again the 220 * next time somebody inserts a probe. 221 */ 222 hlist_del(&kip->hlist); 223 if (hlist_empty(&kprobe_insn_pages)) { 224 INIT_HLIST_NODE(&kip->hlist); 225 hlist_add_head(&kip->hlist, 226 &kprobe_insn_pages); 227 } else { 228 module_free(NULL, kip->insns); 229 kfree(kip); 230 } 231 return 1; 232 } 233 return 0; 234} 235 236static int __kprobes collect_garbage_slots(void) 237{ 238 struct kprobe_insn_page *kip; 239 struct hlist_node *pos, *next; 240 241 /* Ensure no-one is preepmted on the garbages */ 242 if (check_safety()) 243 return -EAGAIN; 244 245 hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) { 246 int i; 247 if (kip->ngarbage == 0) 248 continue; 249 kip->ngarbage = 0; /* we will collect all garbages */ 250 for (i = 0; i < INSNS_PER_PAGE; i++) { 251 if (kip->slot_used[i] == SLOT_DIRTY && 252 collect_one_slot(kip, i)) 253 break; 254 } 255 } 256 kprobe_garbage_slots = 0; 257 return 0; 258} 259 260void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) 261{ 262 struct kprobe_insn_page *kip; 263 struct hlist_node *pos; 264 265 mutex_lock(&kprobe_insn_mutex); 266 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { 267 if (kip->insns <= slot && 268 slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { 269 int i = (slot - kip->insns) / MAX_INSN_SIZE; 270 if (dirty) { 271 kip->slot_used[i] = SLOT_DIRTY; 272 kip->ngarbage++; 273 } else { 274 collect_one_slot(kip, i); 275 } 276 break; 277 } 278 } 279 280 if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE) 281 collect_garbage_slots(); 282 283 mutex_unlock(&kprobe_insn_mutex); 284} 285#endif 286 287/* We have preemption disabled.. so it is safe to use __ versions */ 288static inline void set_kprobe_instance(struct kprobe *kp) 289{ 290 __get_cpu_var(kprobe_instance) = kp; 291} 292 293static inline void reset_kprobe_instance(void) 294{ 295 __get_cpu_var(kprobe_instance) = NULL; 296} 297 298/* 299 * This routine is called either: 300 * - under the kprobe_mutex - during kprobe_[un]register() 301 * OR 302 * - with preemption disabled - from arch/xxx/kernel/kprobes.c 303 */ 304struct kprobe __kprobes *get_kprobe(void *addr) 305{ 306 struct hlist_head *head; 307 struct hlist_node *node; 308 struct kprobe *p; 309 310 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; 311 hlist_for_each_entry_rcu(p, node, head, hlist) { 312 if (p->addr == addr) 313 return p; 314 } 315 return NULL; 316} 317 318/* Arm a kprobe with text_mutex */ 319static void __kprobes arm_kprobe(struct kprobe *kp) 320{ 321 mutex_lock(&text_mutex); 322 arch_arm_kprobe(kp); 323 mutex_unlock(&text_mutex); 324} 325 326/* Disarm a kprobe with text_mutex */ 327static void __kprobes disarm_kprobe(struct kprobe *kp) 328{ 329 mutex_lock(&text_mutex); 330 arch_disarm_kprobe(kp); 331 mutex_unlock(&text_mutex); 332} 333 334/* 335 * Aggregate handlers for multiple kprobes support - these handlers 336 * take care of invoking the individual kprobe handlers on p->list 337 */ 338static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) 339{ 340 struct kprobe *kp; 341 342 list_for_each_entry_rcu(kp, &p->list, list) { 343 if (kp->pre_handler && likely(!kprobe_disabled(kp))) { 344 set_kprobe_instance(kp); 345 if (kp->pre_handler(kp, regs)) 346 return 1; 347 } 348 reset_kprobe_instance(); 349 } 350 return 0; 351} 352 353static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, 354 unsigned long flags) 355{ 356 struct kprobe *kp; 357 358 list_for_each_entry_rcu(kp, &p->list, list) { 359 if (kp->post_handler && likely(!kprobe_disabled(kp))) { 360 set_kprobe_instance(kp); 361 kp->post_handler(kp, regs, flags); 362 reset_kprobe_instance(); 363 } 364 } 365} 366 367static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, 368 int trapnr) 369{ 370 struct kprobe *cur = __get_cpu_var(kprobe_instance); 371 372 /* 373 * if we faulted "during" the execution of a user specified 374 * probe handler, invoke just that probe's fault handler 375 */ 376 if (cur && cur->fault_handler) { 377 if (cur->fault_handler(cur, regs, trapnr)) 378 return 1; 379 } 380 return 0; 381} 382 383static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) 384{ 385 struct kprobe *cur = __get_cpu_var(kprobe_instance); 386 int ret = 0; 387 388 if (cur && cur->break_handler) { 389 if (cur->break_handler(cur, regs)) 390 ret = 1; 391 } 392 reset_kprobe_instance(); 393 return ret; 394} 395 396/* Walks the list and increments nmissed count for multiprobe case */ 397void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) 398{ 399 struct kprobe *kp; 400 if (p->pre_handler != aggr_pre_handler) { 401 p->nmissed++; 402 } else { 403 list_for_each_entry_rcu(kp, &p->list, list) 404 kp->nmissed++; 405 } 406 return; 407} 408 409void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, 410 struct hlist_head *head) 411{ 412 struct kretprobe *rp = ri->rp; 413 414 /* remove rp inst off the rprobe_inst_table */ 415 hlist_del(&ri->hlist); 416 INIT_HLIST_NODE(&ri->hlist); 417 if (likely(rp)) { 418 spin_lock(&rp->lock); 419 hlist_add_head(&ri->hlist, &rp->free_instances); 420 spin_unlock(&rp->lock); 421 } else 422 /* Unregistering */ 423 hlist_add_head(&ri->hlist, head); 424} 425 426void __kprobes kretprobe_hash_lock(struct task_struct *tsk, 427 struct hlist_head **head, unsigned long *flags) 428{ 429 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); 430 spinlock_t *hlist_lock; 431 432 *head = &kretprobe_inst_table[hash]; 433 hlist_lock = kretprobe_table_lock_ptr(hash); 434 spin_lock_irqsave(hlist_lock, *flags); 435} 436 437static void __kprobes kretprobe_table_lock(unsigned long hash, 438 unsigned long *flags) 439{ 440 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); 441 spin_lock_irqsave(hlist_lock, *flags); 442} 443 444void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, 445 unsigned long *flags) 446{ 447 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); 448 spinlock_t *hlist_lock; 449 450 hlist_lock = kretprobe_table_lock_ptr(hash); 451 spin_unlock_irqrestore(hlist_lock, *flags); 452} 453 454void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags) 455{ 456 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); 457 spin_unlock_irqrestore(hlist_lock, *flags); 458} 459 460/* 461 * This function is called from finish_task_switch when task tk becomes dead, 462 * so that we can recycle any function-return probe instances associated 463 * with this task. These left over instances represent probed functions 464 * that have been called but will never return. 465 */ 466void __kprobes kprobe_flush_task(struct task_struct *tk) 467{ 468 struct kretprobe_instance *ri; 469 struct hlist_head *head, empty_rp; 470 struct hlist_node *node, *tmp; 471 unsigned long hash, flags = 0; 472 473 if (unlikely(!kprobes_initialized)) 474 /* Early boot. kretprobe_table_locks not yet initialized. */ 475 return; 476 477 hash = hash_ptr(tk, KPROBE_HASH_BITS); 478 head = &kretprobe_inst_table[hash]; 479 kretprobe_table_lock(hash, &flags); 480 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { 481 if (ri->task == tk) 482 recycle_rp_inst(ri, &empty_rp); 483 } 484 kretprobe_table_unlock(hash, &flags); 485 INIT_HLIST_HEAD(&empty_rp); 486 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { 487 hlist_del(&ri->hlist); 488 kfree(ri); 489 } 490} 491 492static inline void free_rp_inst(struct kretprobe *rp) 493{ 494 struct kretprobe_instance *ri; 495 struct hlist_node *pos, *next; 496 497 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { 498 hlist_del(&ri->hlist); 499 kfree(ri); 500 } 501} 502 503static void __kprobes cleanup_rp_inst(struct kretprobe *rp) 504{ 505 unsigned long flags, hash; 506 struct kretprobe_instance *ri; 507 struct hlist_node *pos, *next; 508 struct hlist_head *head; 509 510 /* No race here */ 511 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { 512 kretprobe_table_lock(hash, &flags); 513 head = &kretprobe_inst_table[hash]; 514 hlist_for_each_entry_safe(ri, pos, next, head, hlist) { 515 if (ri->rp == rp) 516 ri->rp = NULL; 517 } 518 kretprobe_table_unlock(hash, &flags); 519 } 520 free_rp_inst(rp); 521} 522 523/* 524 * Keep all fields in the kprobe consistent 525 */ 526static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) 527{ 528 memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); 529 memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); 530} 531 532/* 533* Add the new probe to ap->list. Fail if this is the 534* second jprobe at the address - two jprobes can't coexist 535*/ 536static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) 537{ 538 BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); 539 if (p->break_handler) { 540 if (ap->break_handler) 541 return -EEXIST; 542 list_add_tail_rcu(&p->list, &ap->list); 543 ap->break_handler = aggr_break_handler; 544 } else 545 list_add_rcu(&p->list, &ap->list); 546 if (p->post_handler && !ap->post_handler) 547 ap->post_handler = aggr_post_handler; 548 549 if (kprobe_disabled(ap) && !kprobe_disabled(p)) { 550 ap->flags &= ~KPROBE_FLAG_DISABLED; 551 if (!kprobes_all_disarmed) 552 /* Arm the breakpoint again. */ 553 arm_kprobe(ap); 554 } 555 return 0; 556} 557 558/* 559 * Fill in the required fields of the "manager kprobe". Replace the 560 * earlier kprobe in the hlist with the manager kprobe 561 */ 562static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) 563{ 564 copy_kprobe(p, ap); 565 flush_insn_slot(ap); 566 ap->addr = p->addr; 567 ap->flags = p->flags; 568 ap->pre_handler = aggr_pre_handler; 569 ap->fault_handler = aggr_fault_handler; 570 /* We don't care the kprobe which has gone. */ 571 if (p->post_handler && !kprobe_gone(p)) 572 ap->post_handler = aggr_post_handler; 573 if (p->break_handler && !kprobe_gone(p)) 574 ap->break_handler = aggr_break_handler; 575 576 INIT_LIST_HEAD(&ap->list); 577 list_add_rcu(&p->list, &ap->list); 578 579 hlist_replace_rcu(&p->hlist, &ap->hlist); 580} 581 582/* 583 * This is the second or subsequent kprobe at the address - handle 584 * the intricacies 585 */ 586static int __kprobes register_aggr_kprobe(struct kprobe *old_p, 587 struct kprobe *p) 588{ 589 int ret = 0; 590 struct kprobe *ap = old_p; 591 592 if (old_p->pre_handler != aggr_pre_handler) { 593 /* If old_p is not an aggr_probe, create new aggr_kprobe. */ 594 ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); 595 if (!ap) 596 return -ENOMEM; 597 add_aggr_kprobe(ap, old_p); 598 } 599 600 if (kprobe_gone(ap)) { 601 /* 602 * Attempting to insert new probe at the same location that 603 * had a probe in the module vaddr area which already 604 * freed. So, the instruction slot has already been 605 * released. We need a new slot for the new probe. 606 */ 607 ret = arch_prepare_kprobe(ap); 608 if (ret) 609 /* 610 * Even if fail to allocate new slot, don't need to 611 * free aggr_probe. It will be used next time, or 612 * freed by unregister_kprobe. 613 */ 614 return ret; 615 616 /* 617 * Clear gone flag to prevent allocating new slot again, and 618 * set disabled flag because it is not armed yet. 619 */ 620 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) 621 | KPROBE_FLAG_DISABLED; 622 } 623 624 copy_kprobe(ap, p); 625 return add_new_kprobe(ap, p); 626} 627 628/* Try to disable aggr_kprobe, and return 1 if succeeded.*/ 629static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p) 630{ 631 struct kprobe *kp; 632 633 list_for_each_entry_rcu(kp, &p->list, list) { 634 if (!kprobe_disabled(kp)) 635 /* 636 * There is an active probe on the list. 637 * We can't disable aggr_kprobe. 638 */ 639 return 0; 640 } 641 p->flags |= KPROBE_FLAG_DISABLED; 642 return 1; 643} 644 645static int __kprobes in_kprobes_functions(unsigned long addr) 646{ 647 struct kprobe_blackpoint *kb; 648 649 if (addr >= (unsigned long)__kprobes_text_start && 650 addr < (unsigned long)__kprobes_text_end) 651 return -EINVAL; 652 /* 653 * If there exists a kprobe_blacklist, verify and 654 * fail any probe registration in the prohibited area 655 */ 656 for (kb = kprobe_blacklist; kb->name != NULL; kb++) { 657 if (kb->start_addr) { 658 if (addr >= kb->start_addr && 659 addr < (kb->start_addr + kb->range)) 660 return -EINVAL; 661 } 662 } 663 return 0; 664} 665 666/* 667 * If we have a symbol_name argument, look it up and add the offset field 668 * to it. This way, we can specify a relative address to a symbol. 669 */ 670static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) 671{ 672 kprobe_opcode_t *addr = p->addr; 673 if (p->symbol_name) { 674 if (addr) 675 return NULL; 676 kprobe_lookup_name(p->symbol_name, addr); 677 } 678 679 if (!addr) 680 return NULL; 681 return (kprobe_opcode_t *)(((char *)addr) + p->offset); 682} 683 684int __kprobes register_kprobe(struct kprobe *p) 685{ 686 int ret = 0; 687 struct kprobe *old_p; 688 struct module *probed_mod; 689 kprobe_opcode_t *addr; 690 691 addr = kprobe_addr(p); 692 if (!addr) 693 return -EINVAL; 694 p->addr = addr; 695 696 preempt_disable(); 697 if (!__kernel_text_address((unsigned long) p->addr) || 698 in_kprobes_functions((unsigned long) p->addr)) { 699 preempt_enable(); 700 return -EINVAL; 701 } 702 703 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ 704 p->flags &= KPROBE_FLAG_DISABLED; 705 706 /* 707 * Check if are we probing a module. 708 */ 709 probed_mod = __module_text_address((unsigned long) p->addr); 710 if (probed_mod) { 711 /* 712 * We must hold a refcount of the probed module while updating 713 * its code to prohibit unexpected unloading. 714 */ 715 if (unlikely(!try_module_get(probed_mod))) { 716 preempt_enable(); 717 return -EINVAL; 718 } 719 /* 720 * If the module freed .init.text, we couldn't insert 721 * kprobes in there. 722 */ 723 if (within_module_init((unsigned long)p->addr, probed_mod) && 724 probed_mod->state != MODULE_STATE_COMING) { 725 module_put(probed_mod); 726 preempt_enable(); 727 return -EINVAL; 728 } 729 } 730 preempt_enable(); 731 732 p->nmissed = 0; 733 INIT_LIST_HEAD(&p->list); 734 mutex_lock(&kprobe_mutex); 735 old_p = get_kprobe(p->addr); 736 if (old_p) { 737 ret = register_aggr_kprobe(old_p, p); 738 goto out; 739 } 740 741 mutex_lock(&text_mutex); 742 ret = arch_prepare_kprobe(p); 743 if (ret) 744 goto out_unlock_text; 745 746 INIT_HLIST_NODE(&p->hlist); 747 hlist_add_head_rcu(&p->hlist, 748 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); 749 750 if (!kprobes_all_disarmed && !kprobe_disabled(p)) 751 arch_arm_kprobe(p); 752 753out_unlock_text: 754 mutex_unlock(&text_mutex); 755out: 756 mutex_unlock(&kprobe_mutex); 757 758 if (probed_mod) 759 module_put(probed_mod); 760 761 return ret; 762} 763EXPORT_SYMBOL_GPL(register_kprobe); 764 765/* Check passed kprobe is valid and return kprobe in kprobe_table. */ 766static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) 767{ 768 struct kprobe *old_p, *list_p; 769 770 old_p = get_kprobe(p->addr); 771 if (unlikely(!old_p)) 772 return NULL; 773 774 if (p != old_p) { 775 list_for_each_entry_rcu(list_p, &old_p->list, list) 776 if (list_p == p) 777 /* kprobe p is a valid probe */ 778 goto valid; 779 return NULL; 780 } 781valid: 782 return old_p; 783} 784 785/* 786 * Unregister a kprobe without a scheduler synchronization. 787 */ 788static int __kprobes __unregister_kprobe_top(struct kprobe *p) 789{ 790 struct kprobe *old_p, *list_p; 791 792 old_p = __get_valid_kprobe(p); 793 if (old_p == NULL) 794 return -EINVAL; 795 796 if (old_p == p || 797 (old_p->pre_handler == aggr_pre_handler && 798 list_is_singular(&old_p->list))) { 799 /* 800 * Only probe on the hash list. Disarm only if kprobes are 801 * enabled and not gone - otherwise, the breakpoint would 802 * already have been removed. We save on flushing icache. 803 */ 804 if (!kprobes_all_disarmed && !kprobe_disabled(old_p)) 805 disarm_kprobe(p); 806 hlist_del_rcu(&old_p->hlist); 807 } else { 808 if (p->break_handler && !kprobe_gone(p)) 809 old_p->break_handler = NULL; 810 if (p->post_handler && !kprobe_gone(p)) { 811 list_for_each_entry_rcu(list_p, &old_p->list, list) { 812 if ((list_p != p) && (list_p->post_handler)) 813 goto noclean; 814 } 815 old_p->post_handler = NULL; 816 } 817noclean: 818 list_del_rcu(&p->list); 819 if (!kprobe_disabled(old_p)) { 820 try_to_disable_aggr_kprobe(old_p); 821 if (!kprobes_all_disarmed && kprobe_disabled(old_p)) 822 disarm_kprobe(old_p); 823 } 824 } 825 return 0; 826} 827 828static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) 829{ 830 struct kprobe *old_p; 831 832 if (list_empty(&p->list)) 833 arch_remove_kprobe(p); 834 else if (list_is_singular(&p->list)) { 835 /* "p" is the last child of an aggr_kprobe */ 836 old_p = list_entry(p->list.next, struct kprobe, list); 837 list_del(&p->list); 838 arch_remove_kprobe(old_p); 839 kfree(old_p); 840 } 841} 842 843int __kprobes register_kprobes(struct kprobe **kps, int num) 844{ 845 int i, ret = 0; 846 847 if (num <= 0) 848 return -EINVAL; 849 for (i = 0; i < num; i++) { 850 ret = register_kprobe(kps[i]); 851 if (ret < 0) { 852 if (i > 0) 853 unregister_kprobes(kps, i); 854 break; 855 } 856 } 857 return ret; 858} 859EXPORT_SYMBOL_GPL(register_kprobes); 860 861void __kprobes unregister_kprobe(struct kprobe *p) 862{ 863 unregister_kprobes(&p, 1); 864} 865EXPORT_SYMBOL_GPL(unregister_kprobe); 866 867void __kprobes unregister_kprobes(struct kprobe **kps, int num) 868{ 869 int i; 870 871 if (num <= 0) 872 return; 873 mutex_lock(&kprobe_mutex); 874 for (i = 0; i < num; i++) 875 if (__unregister_kprobe_top(kps[i]) < 0) 876 kps[i]->addr = NULL; 877 mutex_unlock(&kprobe_mutex); 878 879 synchronize_sched(); 880 for (i = 0; i < num; i++) 881 if (kps[i]->addr) 882 __unregister_kprobe_bottom(kps[i]); 883} 884EXPORT_SYMBOL_GPL(unregister_kprobes); 885 886static struct notifier_block kprobe_exceptions_nb = { 887 .notifier_call = kprobe_exceptions_notify, 888 .priority = 0x7fffffff /* we need to be notified first */ 889}; 890 891unsigned long __weak arch_deref_entry_point(void *entry) 892{ 893 return (unsigned long)entry; 894} 895 896int __kprobes register_jprobes(struct jprobe **jps, int num) 897{ 898 struct jprobe *jp; 899 int ret = 0, i; 900 901 if (num <= 0) 902 return -EINVAL; 903 for (i = 0; i < num; i++) { 904 unsigned long addr; 905 jp = jps[i]; 906 addr = arch_deref_entry_point(jp->entry); 907 908 if (!kernel_text_address(addr)) 909 ret = -EINVAL; 910 else { 911 /* Todo: Verify probepoint is a function entry point */ 912 jp->kp.pre_handler = setjmp_pre_handler; 913 jp->kp.break_handler = longjmp_break_handler; 914 ret = register_kprobe(&jp->kp); 915 } 916 if (ret < 0) { 917 if (i > 0) 918 unregister_jprobes(jps, i); 919 break; 920 } 921 } 922 return ret; 923} 924EXPORT_SYMBOL_GPL(register_jprobes); 925 926int __kprobes register_jprobe(struct jprobe *jp) 927{ 928 return register_jprobes(&jp, 1); 929} 930EXPORT_SYMBOL_GPL(register_jprobe); 931 932void __kprobes unregister_jprobe(struct jprobe *jp) 933{ 934 unregister_jprobes(&jp, 1); 935} 936EXPORT_SYMBOL_GPL(unregister_jprobe); 937 938void __kprobes unregister_jprobes(struct jprobe **jps, int num) 939{ 940 int i; 941 942 if (num <= 0) 943 return; 944 mutex_lock(&kprobe_mutex); 945 for (i = 0; i < num; i++) 946 if (__unregister_kprobe_top(&jps[i]->kp) < 0) 947 jps[i]->kp.addr = NULL; 948 mutex_unlock(&kprobe_mutex); 949 950 synchronize_sched(); 951 for (i = 0; i < num; i++) { 952 if (jps[i]->kp.addr) 953 __unregister_kprobe_bottom(&jps[i]->kp); 954 } 955} 956EXPORT_SYMBOL_GPL(unregister_jprobes); 957 958#ifdef CONFIG_KRETPROBES 959/* 960 * This kprobe pre_handler is registered with every kretprobe. When probe 961 * hits it will set up the return probe. 962 */ 963static int __kprobes pre_handler_kretprobe(struct kprobe *p, 964 struct pt_regs *regs) 965{ 966 struct kretprobe *rp = container_of(p, struct kretprobe, kp); 967 unsigned long hash, flags = 0; 968 struct kretprobe_instance *ri; 969 970 /*TODO: consider to only swap the RA after the last pre_handler fired */ 971 hash = hash_ptr(current, KPROBE_HASH_BITS); 972 spin_lock_irqsave(&rp->lock, flags); 973 if (!hlist_empty(&rp->free_instances)) { 974 ri = hlist_entry(rp->free_instances.first, 975 struct kretprobe_instance, hlist); 976 hlist_del(&ri->hlist); 977 spin_unlock_irqrestore(&rp->lock, flags); 978 979 ri->rp = rp; 980 ri->task = current; 981 982 if (rp->entry_handler && rp->entry_handler(ri, regs)) 983 return 0; 984 985 arch_prepare_kretprobe(ri, regs); 986 987 /* XXX(hch): why is there no hlist_move_head? */ 988 INIT_HLIST_NODE(&ri->hlist); 989 kretprobe_table_lock(hash, &flags); 990 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); 991 kretprobe_table_unlock(hash, &flags); 992 } else { 993 rp->nmissed++; 994 spin_unlock_irqrestore(&rp->lock, flags); 995 } 996 return 0; 997} 998 999int __kprobes register_kretprobe(struct kretprobe *rp) 1000{ 1001 int ret = 0; 1002 struct kretprobe_instance *inst; 1003 int i; 1004 void *addr; 1005 1006 if (kretprobe_blacklist_size) { 1007 addr = kprobe_addr(&rp->kp); 1008 if (!addr) 1009 return -EINVAL; 1010 1011 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { 1012 if (kretprobe_blacklist[i].addr == addr) 1013 return -EINVAL; 1014 } 1015 } 1016 1017 rp->kp.pre_handler = pre_handler_kretprobe; 1018 rp->kp.post_handler = NULL; 1019 rp->kp.fault_handler = NULL; 1020 rp->kp.break_handler = NULL; 1021 1022 /* Pre-allocate memory for max kretprobe instances */ 1023 if (rp->maxactive <= 0) { 1024#ifdef CONFIG_PREEMPT 1025 rp->maxactive = max(10, 2 * NR_CPUS); 1026#else 1027 rp->maxactive = NR_CPUS; 1028#endif 1029 } 1030 spin_lock_init(&rp->lock); 1031 INIT_HLIST_HEAD(&rp->free_instances); 1032 for (i = 0; i < rp->maxactive; i++) { 1033 inst = kmalloc(sizeof(struct kretprobe_instance) + 1034 rp->data_size, GFP_KERNEL); 1035 if (inst == NULL) { 1036 free_rp_inst(rp); 1037 return -ENOMEM; 1038 } 1039 INIT_HLIST_NODE(&inst->hlist); 1040 hlist_add_head(&inst->hlist, &rp->free_instances); 1041 } 1042 1043 rp->nmissed = 0; 1044 /* Establish function entry probe point */ 1045 ret = register_kprobe(&rp->kp); 1046 if (ret != 0) 1047 free_rp_inst(rp); 1048 return ret; 1049} 1050EXPORT_SYMBOL_GPL(register_kretprobe); 1051 1052int __kprobes register_kretprobes(struct kretprobe **rps, int num) 1053{ 1054 int ret = 0, i; 1055 1056 if (num <= 0) 1057 return -EINVAL; 1058 for (i = 0; i < num; i++) { 1059 ret = register_kretprobe(rps[i]); 1060 if (ret < 0) { 1061 if (i > 0) 1062 unregister_kretprobes(rps, i); 1063 break; 1064 } 1065 } 1066 return ret; 1067} 1068EXPORT_SYMBOL_GPL(register_kretprobes); 1069 1070void __kprobes unregister_kretprobe(struct kretprobe *rp) 1071{ 1072 unregister_kretprobes(&rp, 1); 1073} 1074EXPORT_SYMBOL_GPL(unregister_kretprobe); 1075 1076void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) 1077{ 1078 int i; 1079 1080 if (num <= 0) 1081 return; 1082 mutex_lock(&kprobe_mutex); 1083 for (i = 0; i < num; i++) 1084 if (__unregister_kprobe_top(&rps[i]->kp) < 0) 1085 rps[i]->kp.addr = NULL; 1086 mutex_unlock(&kprobe_mutex); 1087 1088 synchronize_sched(); 1089 for (i = 0; i < num; i++) { 1090 if (rps[i]->kp.addr) { 1091 __unregister_kprobe_bottom(&rps[i]->kp); 1092 cleanup_rp_inst(rps[i]); 1093 } 1094 } 1095} 1096EXPORT_SYMBOL_GPL(unregister_kretprobes); 1097 1098#else /* CONFIG_KRETPROBES */ 1099int __kprobes register_kretprobe(struct kretprobe *rp) 1100{ 1101 return -ENOSYS; 1102} 1103EXPORT_SYMBOL_GPL(register_kretprobe); 1104 1105int __kprobes register_kretprobes(struct kretprobe **rps, int num) 1106{ 1107 return -ENOSYS; 1108} 1109EXPORT_SYMBOL_GPL(register_kretprobes); 1110 1111void __kprobes unregister_kretprobe(struct kretprobe *rp) 1112{ 1113} 1114EXPORT_SYMBOL_GPL(unregister_kretprobe); 1115 1116void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) 1117{ 1118} 1119EXPORT_SYMBOL_GPL(unregister_kretprobes); 1120 1121static int __kprobes pre_handler_kretprobe(struct kprobe *p, 1122 struct pt_regs *regs) 1123{ 1124 return 0; 1125} 1126 1127#endif /* CONFIG_KRETPROBES */ 1128 1129/* Set the kprobe gone and remove its instruction buffer. */ 1130static void __kprobes kill_kprobe(struct kprobe *p) 1131{ 1132 struct kprobe *kp; 1133 1134 p->flags |= KPROBE_FLAG_GONE; 1135 if (p->pre_handler == aggr_pre_handler) { 1136 /* 1137 * If this is an aggr_kprobe, we have to list all the 1138 * chained probes and mark them GONE. 1139 */ 1140 list_for_each_entry_rcu(kp, &p->list, list) 1141 kp->flags |= KPROBE_FLAG_GONE; 1142 p->post_handler = NULL; 1143 p->break_handler = NULL; 1144 } 1145 /* 1146 * Here, we can remove insn_slot safely, because no thread calls 1147 * the original probed function (which will be freed soon) any more. 1148 */ 1149 arch_remove_kprobe(p); 1150} 1151 1152/* Module notifier call back, checking kprobes on the module */ 1153static int __kprobes kprobes_module_callback(struct notifier_block *nb, 1154 unsigned long val, void *data) 1155{ 1156 struct module *mod = data; 1157 struct hlist_head *head; 1158 struct hlist_node *node; 1159 struct kprobe *p; 1160 unsigned int i; 1161 int checkcore = (val == MODULE_STATE_GOING); 1162 1163 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) 1164 return NOTIFY_DONE; 1165 1166 /* 1167 * When MODULE_STATE_GOING was notified, both of module .text and 1168 * .init.text sections would be freed. When MODULE_STATE_LIVE was 1169 * notified, only .init.text section would be freed. We need to 1170 * disable kprobes which have been inserted in the sections. 1171 */ 1172 mutex_lock(&kprobe_mutex); 1173 for (i = 0; i < KPROBE_TABLE_SIZE; i++) { 1174 head = &kprobe_table[i]; 1175 hlist_for_each_entry_rcu(p, node, head, hlist) 1176 if (within_module_init((unsigned long)p->addr, mod) || 1177 (checkcore && 1178 within_module_core((unsigned long)p->addr, mod))) { 1179 /* 1180 * The vaddr this probe is installed will soon 1181 * be vfreed buy not synced to disk. Hence, 1182 * disarming the breakpoint isn't needed. 1183 */ 1184 kill_kprobe(p); 1185 } 1186 } 1187 mutex_unlock(&kprobe_mutex); 1188 return NOTIFY_DONE; 1189} 1190 1191static struct notifier_block kprobe_module_nb = { 1192 .notifier_call = kprobes_module_callback, 1193 .priority = 0 1194}; 1195 1196static int __init init_kprobes(void) 1197{ 1198 int i, err = 0; 1199 unsigned long offset = 0, size = 0; 1200 char *modname, namebuf[128]; 1201 const char *symbol_name; 1202 void *addr; 1203 struct kprobe_blackpoint *kb; 1204 1205 /* FIXME allocate the probe table, currently defined statically */ 1206 /* initialize all list heads */ 1207 for (i = 0; i < KPROBE_TABLE_SIZE; i++) { 1208 INIT_HLIST_HEAD(&kprobe_table[i]); 1209 INIT_HLIST_HEAD(&kretprobe_inst_table[i]); 1210 spin_lock_init(&(kretprobe_table_locks[i].lock)); 1211 } 1212 1213 /* 1214 * Lookup and populate the kprobe_blacklist. 1215 * 1216 * Unlike the kretprobe blacklist, we'll need to determine 1217 * the range of addresses that belong to the said functions, 1218 * since a kprobe need not necessarily be at the beginning 1219 * of a function. 1220 */ 1221 for (kb = kprobe_blacklist; kb->name != NULL; kb++) { 1222 kprobe_lookup_name(kb->name, addr); 1223 if (!addr) 1224 continue; 1225 1226 kb->start_addr = (unsigned long)addr; 1227 symbol_name = kallsyms_lookup(kb->start_addr, 1228 &size, &offset, &modname, namebuf); 1229 if (!symbol_name) 1230 kb->range = 0; 1231 else 1232 kb->range = size; 1233 } 1234 1235 if (kretprobe_blacklist_size) { 1236 /* lookup the function address from its name */ 1237 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { 1238 kprobe_lookup_name(kretprobe_blacklist[i].name, 1239 kretprobe_blacklist[i].addr); 1240 if (!kretprobe_blacklist[i].addr) 1241 printk("kretprobe: lookup failed: %s\n", 1242 kretprobe_blacklist[i].name); 1243 } 1244 } 1245 1246 /* By default, kprobes are armed */ 1247 kprobes_all_disarmed = false; 1248 1249 err = arch_init_kprobes(); 1250 if (!err) 1251 err = register_die_notifier(&kprobe_exceptions_nb); 1252 if (!err) 1253 err = register_module_notifier(&kprobe_module_nb); 1254 1255 kprobes_initialized = (err == 0); 1256 1257 if (!err) 1258 init_test_probes(); 1259 return err; 1260} 1261 1262#ifdef CONFIG_DEBUG_FS 1263static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, 1264 const char *sym, int offset,char *modname) 1265{ 1266 char *kprobe_type; 1267 1268 if (p->pre_handler == pre_handler_kretprobe) 1269 kprobe_type = "r"; 1270 else if (p->pre_handler == setjmp_pre_handler) 1271 kprobe_type = "j"; 1272 else 1273 kprobe_type = "k"; 1274 if (sym) 1275 seq_printf(pi, "%p %s %s+0x%x %s %s%s\n", 1276 p->addr, kprobe_type, sym, offset, 1277 (modname ? modname : " "), 1278 (kprobe_gone(p) ? "[GONE]" : ""), 1279 ((kprobe_disabled(p) && !kprobe_gone(p)) ? 1280 "[DISABLED]" : "")); 1281 else 1282 seq_printf(pi, "%p %s %p %s%s\n", 1283 p->addr, kprobe_type, p->addr, 1284 (kprobe_gone(p) ? "[GONE]" : ""), 1285 ((kprobe_disabled(p) && !kprobe_gone(p)) ? 1286 "[DISABLED]" : "")); 1287} 1288 1289static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) 1290{ 1291 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; 1292} 1293 1294static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) 1295{ 1296 (*pos)++; 1297 if (*pos >= KPROBE_TABLE_SIZE) 1298 return NULL; 1299 return pos; 1300} 1301 1302static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) 1303{ 1304 /* Nothing to do */ 1305} 1306 1307static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) 1308{ 1309 struct hlist_head *head; 1310 struct hlist_node *node; 1311 struct kprobe *p, *kp; 1312 const char *sym = NULL; 1313 unsigned int i = *(loff_t *) v; 1314 unsigned long offset = 0; 1315 char *modname, namebuf[128]; 1316 1317 head = &kprobe_table[i]; 1318 preempt_disable(); 1319 hlist_for_each_entry_rcu(p, node, head, hlist) { 1320 sym = kallsyms_lookup((unsigned long)p->addr, NULL, 1321 &offset, &modname, namebuf); 1322 if (p->pre_handler == aggr_pre_handler) { 1323 list_for_each_entry_rcu(kp, &p->list, list) 1324 report_probe(pi, kp, sym, offset, modname); 1325 } else 1326 report_probe(pi, p, sym, offset, modname); 1327 } 1328 preempt_enable(); 1329 return 0; 1330} 1331 1332static struct seq_operations kprobes_seq_ops = { 1333 .start = kprobe_seq_start, 1334 .next = kprobe_seq_next, 1335 .stop = kprobe_seq_stop, 1336 .show = show_kprobe_addr 1337}; 1338 1339static int __kprobes kprobes_open(struct inode *inode, struct file *filp) 1340{ 1341 return seq_open(filp, &kprobes_seq_ops); 1342} 1343 1344static struct file_operations debugfs_kprobes_operations = { 1345 .open = kprobes_open, 1346 .read = seq_read, 1347 .llseek = seq_lseek, 1348 .release = seq_release, 1349}; 1350 1351/* Disable one kprobe */ 1352int __kprobes disable_kprobe(struct kprobe *kp) 1353{ 1354 int ret = 0; 1355 struct kprobe *p; 1356 1357 mutex_lock(&kprobe_mutex); 1358 1359 /* Check whether specified probe is valid. */ 1360 p = __get_valid_kprobe(kp); 1361 if (unlikely(p == NULL)) { 1362 ret = -EINVAL; 1363 goto out; 1364 } 1365 1366 /* If the probe is already disabled (or gone), just return */ 1367 if (kprobe_disabled(kp)) 1368 goto out; 1369 1370 kp->flags |= KPROBE_FLAG_DISABLED; 1371 if (p != kp) 1372 /* When kp != p, p is always enabled. */ 1373 try_to_disable_aggr_kprobe(p); 1374 1375 if (!kprobes_all_disarmed && kprobe_disabled(p)) 1376 disarm_kprobe(p); 1377out: 1378 mutex_unlock(&kprobe_mutex); 1379 return ret; 1380} 1381EXPORT_SYMBOL_GPL(disable_kprobe); 1382 1383/* Enable one kprobe */ 1384int __kprobes enable_kprobe(struct kprobe *kp) 1385{ 1386 int ret = 0; 1387 struct kprobe *p; 1388 1389 mutex_lock(&kprobe_mutex); 1390 1391 /* Check whether specified probe is valid. */ 1392 p = __get_valid_kprobe(kp); 1393 if (unlikely(p == NULL)) { 1394 ret = -EINVAL; 1395 goto out; 1396 } 1397 1398 if (kprobe_gone(kp)) { 1399 /* This kprobe has gone, we couldn't enable it. */ 1400 ret = -EINVAL; 1401 goto out; 1402 } 1403 1404 if (!kprobes_all_disarmed && kprobe_disabled(p)) 1405 arm_kprobe(p); 1406 1407 p->flags &= ~KPROBE_FLAG_DISABLED; 1408 if (p != kp) 1409 kp->flags &= ~KPROBE_FLAG_DISABLED; 1410out: 1411 mutex_unlock(&kprobe_mutex); 1412 return ret; 1413} 1414EXPORT_SYMBOL_GPL(enable_kprobe); 1415 1416static void __kprobes arm_all_kprobes(void) 1417{ 1418 struct hlist_head *head; 1419 struct hlist_node *node; 1420 struct kprobe *p; 1421 unsigned int i; 1422 1423 mutex_lock(&kprobe_mutex); 1424 1425 /* If kprobes are armed, just return */ 1426 if (!kprobes_all_disarmed) 1427 goto already_enabled; 1428 1429 mutex_lock(&text_mutex); 1430 for (i = 0; i < KPROBE_TABLE_SIZE; i++) { 1431 head = &kprobe_table[i]; 1432 hlist_for_each_entry_rcu(p, node, head, hlist) 1433 if (!kprobe_disabled(p)) 1434 arch_arm_kprobe(p); 1435 } 1436 mutex_unlock(&text_mutex); 1437 1438 kprobes_all_disarmed = false; 1439 printk(KERN_INFO "Kprobes globally enabled\n"); 1440 1441already_enabled: 1442 mutex_unlock(&kprobe_mutex); 1443 return; 1444} 1445 1446static void __kprobes disarm_all_kprobes(void) 1447{ 1448 struct hlist_head *head; 1449 struct hlist_node *node; 1450 struct kprobe *p; 1451 unsigned int i; 1452 1453 mutex_lock(&kprobe_mutex); 1454 1455 /* If kprobes are already disarmed, just return */ 1456 if (kprobes_all_disarmed) 1457 goto already_disabled; 1458 1459 kprobes_all_disarmed = true; 1460 printk(KERN_INFO "Kprobes globally disabled\n"); 1461 mutex_lock(&text_mutex); 1462 for (i = 0; i < KPROBE_TABLE_SIZE; i++) { 1463 head = &kprobe_table[i]; 1464 hlist_for_each_entry_rcu(p, node, head, hlist) { 1465 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) 1466 arch_disarm_kprobe(p); 1467 } 1468 } 1469 1470 mutex_unlock(&text_mutex); 1471 mutex_unlock(&kprobe_mutex); 1472 /* Allow all currently running kprobes to complete */ 1473 synchronize_sched(); 1474 return; 1475 1476already_disabled: 1477 mutex_unlock(&kprobe_mutex); 1478 return; 1479} 1480 1481/* 1482 * XXX: The debugfs bool file interface doesn't allow for callbacks 1483 * when the bool state is switched. We can reuse that facility when 1484 * available 1485 */ 1486static ssize_t read_enabled_file_bool(struct file *file, 1487 char __user *user_buf, size_t count, loff_t *ppos) 1488{ 1489 char buf[3]; 1490 1491 if (!kprobes_all_disarmed) 1492 buf[0] = '1'; 1493 else 1494 buf[0] = '0'; 1495 buf[1] = '\n'; 1496 buf[2] = 0x00; 1497 return simple_read_from_buffer(user_buf, count, ppos, buf, 2); 1498} 1499 1500static ssize_t write_enabled_file_bool(struct file *file, 1501 const char __user *user_buf, size_t count, loff_t *ppos) 1502{ 1503 char buf[32]; 1504 int buf_size; 1505 1506 buf_size = min(count, (sizeof(buf)-1)); 1507 if (copy_from_user(buf, user_buf, buf_size)) 1508 return -EFAULT; 1509 1510 switch (buf[0]) { 1511 case 'y': 1512 case 'Y': 1513 case '1': 1514 arm_all_kprobes(); 1515 break; 1516 case 'n': 1517 case 'N': 1518 case '0': 1519 disarm_all_kprobes(); 1520 break; 1521 } 1522 1523 return count; 1524} 1525 1526static struct file_operations fops_kp = { 1527 .read = read_enabled_file_bool, 1528 .write = write_enabled_file_bool, 1529}; 1530 1531static int __kprobes debugfs_kprobe_init(void) 1532{ 1533 struct dentry *dir, *file; 1534 unsigned int value = 1; 1535 1536 dir = debugfs_create_dir("kprobes", NULL); 1537 if (!dir) 1538 return -ENOMEM; 1539 1540 file = debugfs_create_file("list", 0444, dir, NULL, 1541 &debugfs_kprobes_operations); 1542 if (!file) { 1543 debugfs_remove(dir); 1544 return -ENOMEM; 1545 } 1546 1547 file = debugfs_create_file("enabled", 0600, dir, 1548 &value, &fops_kp); 1549 if (!file) { 1550 debugfs_remove(dir); 1551 return -ENOMEM; 1552 } 1553 1554 return 0; 1555} 1556 1557late_initcall(debugfs_kprobe_init); 1558#endif /* CONFIG_DEBUG_FS */ 1559 1560module_init(init_kprobes); 1561 1562/* defined in arch/.../kernel/kprobes.c */ 1563EXPORT_SYMBOL_GPL(jprobe_return); 1564